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-rw-r--r--Documentation/device-mapper/cache-policies.txt77
-rw-r--r--Documentation/device-mapper/cache.txt243
-rw-r--r--drivers/md/Kconfig55
-rw-r--r--drivers/md/Makefile6
-rw-r--r--drivers/md/dm-bio-prison.c155
-rw-r--r--drivers/md/dm-bio-prison.h58
-rw-r--r--drivers/md/dm-bufio.c2
-rw-r--r--drivers/md/dm-cache-block-types.h54
-rw-r--r--drivers/md/dm-cache-metadata.c1146
-rw-r--r--drivers/md/dm-cache-metadata.h142
-rw-r--r--drivers/md/dm-cache-policy-cleaner.c464
-rw-r--r--drivers/md/dm-cache-policy-internal.h124
-rw-r--r--drivers/md/dm-cache-policy-mq.c1195
-rw-r--r--drivers/md/dm-cache-policy.c161
-rw-r--r--drivers/md/dm-cache-policy.h228
-rw-r--r--drivers/md/dm-cache-target.c2584
-rw-r--r--drivers/md/dm-crypt.c45
-rw-r--r--drivers/md/dm-delay.c12
-rw-r--r--drivers/md/dm-flakey.c11
-rw-r--r--drivers/md/dm-ioctl.c166
-rw-r--r--drivers/md/dm-kcopyd.c121
-rw-r--r--drivers/md/dm-linear.c13
-rw-r--r--drivers/md/dm-mpath.c12
-rw-r--r--drivers/md/dm-raid.c10
-rw-r--r--drivers/md/dm-raid1.c17
-rw-r--r--drivers/md/dm-snap.c33
-rw-r--r--drivers/md/dm-stripe.c27
-rw-r--r--drivers/md/dm-table.c11
-rw-r--r--drivers/md/dm-target.c2
-rw-r--r--drivers/md/dm-thin-metadata.c12
-rw-r--r--drivers/md/dm-thin.c277
-rw-r--r--drivers/md/dm-verity.c8
-rw-r--r--drivers/md/dm-zero.c2
-rw-r--r--drivers/md/dm.c452
-rw-r--r--drivers/md/persistent-data/Kconfig2
-rw-r--r--drivers/md/persistent-data/Makefile2
-rw-r--r--drivers/md/persistent-data/dm-array.c808
-rw-r--r--drivers/md/persistent-data/dm-array.h166
-rw-r--r--drivers/md/persistent-data/dm-bitset.c163
-rw-r--r--drivers/md/persistent-data/dm-bitset.h165
-rw-r--r--drivers/md/persistent-data/dm-block-manager.c1
-rw-r--r--drivers/md/persistent-data/dm-btree-internal.h1
-rw-r--r--drivers/md/persistent-data/dm-btree-spine.c7
-rw-r--r--drivers/md/persistent-data/dm-btree.c52
-rw-r--r--drivers/md/persistent-data/dm-btree.h15
-rw-r--r--include/linux/device-mapper.h49
-rw-r--r--include/linux/dm-kcopyd.h25
-rw-r--r--include/uapi/linux/dm-ioctl.h11
48 files changed, 8791 insertions, 601 deletions
diff --git a/Documentation/device-mapper/cache-policies.txt b/Documentation/device-mapper/cache-policies.txt
new file mode 100644
index 0000000..d7c440b
--- /dev/null
+++ b/Documentation/device-mapper/cache-policies.txt
@@ -0,0 +1,77 @@
+Guidance for writing policies
+=============================
+
+Try to keep transactionality out of it. The core is careful to
+avoid asking about anything that is migrating. This is a pain, but
+makes it easier to write the policies.
+
+Mappings are loaded into the policy at construction time.
+
+Every bio that is mapped by the target is referred to the policy.
+The policy can return a simple HIT or MISS or issue a migration.
+
+Currently there's no way for the policy to issue background work,
+e.g. to start writing back dirty blocks that are going to be evicte
+soon.
+
+Because we map bios, rather than requests it's easy for the policy
+to get fooled by many small bios. For this reason the core target
+issues periodic ticks to the policy. It's suggested that the policy
+doesn't update states (eg, hit counts) for a block more than once
+for each tick. The core ticks by watching bios complete, and so
+trying to see when the io scheduler has let the ios run.
+
+
+Overview of supplied cache replacement policies
+===============================================
+
+multiqueue
+----------
+
+This policy is the default.
+
+The multiqueue policy has two sets of 16 queues: one set for entries
+waiting for the cache and another one for those in the cache.
+Cache entries in the queues are aged based on logical time. Entry into
+the cache is based on variable thresholds and queue selection is based
+on hit count on entry. The policy aims to take different cache miss
+costs into account and to adjust to varying load patterns automatically.
+
+Message and constructor argument pairs are:
+ 'sequential_threshold <#nr_sequential_ios>' and
+ 'random_threshold <#nr_random_ios>'.
+
+The sequential threshold indicates the number of contiguous I/Os
+required before a stream is treated as sequential. The random threshold
+is the number of intervening non-contiguous I/Os that must be seen
+before the stream is treated as random again.
+
+The sequential and random thresholds default to 512 and 4 respectively.
+
+Large, sequential ios are probably better left on the origin device
+since spindles tend to have good bandwidth. The io_tracker counts
+contiguous I/Os to try to spot when the io is in one of these sequential
+modes.
+
+cleaner
+-------
+
+The cleaner writes back all dirty blocks in a cache to decommission it.
+
+Examples
+========
+
+The syntax for a table is:
+ cache <metadata dev> <cache dev> <origin dev> <block size>
+ <#feature_args> [<feature arg>]*
+ <policy> <#policy_args> [<policy arg>]*
+
+The syntax to send a message using the dmsetup command is:
+ dmsetup message <mapped device> 0 sequential_threshold 1024
+ dmsetup message <mapped device> 0 random_threshold 8
+
+Using dmsetup:
+ dmsetup create blah --table "0 268435456 cache /dev/sdb /dev/sdc \
+ /dev/sdd 512 0 mq 4 sequential_threshold 1024 random_threshold 8"
+ creates a 128GB large mapped device named 'blah' with the
+ sequential threshold set to 1024 and the random_threshold set to 8.
diff --git a/Documentation/device-mapper/cache.txt b/Documentation/device-mapper/cache.txt
new file mode 100644
index 0000000..f50470a
--- /dev/null
+++ b/Documentation/device-mapper/cache.txt
@@ -0,0 +1,243 @@
+Introduction
+============
+
+dm-cache is a device mapper target written by Joe Thornber, Heinz
+Mauelshagen, and Mike Snitzer.
+
+It aims to improve performance of a block device (eg, a spindle) by
+dynamically migrating some of its data to a faster, smaller device
+(eg, an SSD).
+
+This device-mapper solution allows us to insert this caching at
+different levels of the dm stack, for instance above the data device for
+a thin-provisioning pool. Caching solutions that are integrated more
+closely with the virtual memory system should give better performance.
+
+The target reuses the metadata library used in the thin-provisioning
+library.
+
+The decision as to what data to migrate and when is left to a plug-in
+policy module. Several of these have been written as we experiment,
+and we hope other people will contribute others for specific io
+scenarios (eg. a vm image server).
+
+Glossary
+========
+
+ Migration - Movement of the primary copy of a logical block from one
+ device to the other.
+ Promotion - Migration from slow device to fast device.
+ Demotion - Migration from fast device to slow device.
+
+The origin device always contains a copy of the logical block, which
+may be out of date or kept in sync with the copy on the cache device
+(depending on policy).
+
+Design
+======
+
+Sub-devices
+-----------
+
+The target is constructed by passing three devices to it (along with
+other parameters detailed later):
+
+1. An origin device - the big, slow one.
+
+2. A cache device - the small, fast one.
+
+3. A small metadata device - records which blocks are in the cache,
+ which are dirty, and extra hints for use by the policy object.
+ This information could be put on the cache device, but having it
+ separate allows the volume manager to configure it differently,
+ e.g. as a mirror for extra robustness.
+
+Fixed block size
+----------------
+
+The origin is divided up into blocks of a fixed size. This block size
+is configurable when you first create the cache. Typically we've been
+using block sizes of 256k - 1024k.
+
+Having a fixed block size simplifies the target a lot. But it is
+something of a compromise. For instance, a small part of a block may be
+getting hit a lot, yet the whole block will be promoted to the cache.
+So large block sizes are bad because they waste cache space. And small
+block sizes are bad because they increase the amount of metadata (both
+in core and on disk).
+
+Writeback/writethrough
+----------------------
+
+The cache has two modes, writeback and writethrough.
+
+If writeback, the default, is selected then a write to a block that is
+cached will go only to the cache and the block will be marked dirty in
+the metadata.
+
+If writethrough is selected then a write to a cached block will not
+complete until it has hit both the origin and cache devices. Clean
+blocks should remain clean.
+
+A simple cleaner policy is provided, which will clean (write back) all
+dirty blocks in a cache. Useful for decommissioning a cache.
+
+Migration throttling
+--------------------
+
+Migrating data between the origin and cache device uses bandwidth.
+The user can set a throttle to prevent more than a certain amount of
+migration occuring at any one time. Currently we're not taking any
+account of normal io traffic going to the devices. More work needs
+doing here to avoid migrating during those peak io moments.
+
+For the time being, a message "migration_threshold <#sectors>"
+can be used to set the maximum number of sectors being migrated,
+the default being 204800 sectors (or 100MB).
+
+Updating on-disk metadata
+-------------------------
+
+On-disk metadata is committed every time a REQ_SYNC or REQ_FUA bio is
+written. If no such requests are made then commits will occur every
+second. This means the cache behaves like a physical disk that has a
+write cache (the same is true of the thin-provisioning target). If
+power is lost you may lose some recent writes. The metadata should
+always be consistent in spite of any crash.
+
+The 'dirty' state for a cache block changes far too frequently for us
+to keep updating it on the fly. So we treat it as a hint. In normal
+operation it will be written when the dm device is suspended. If the
+system crashes all cache blocks will be assumed dirty when restarted.
+
+Per-block policy hints
+----------------------
+
+Policy plug-ins can store a chunk of data per cache block. It's up to
+the policy how big this chunk is, but it should be kept small. Like the
+dirty flags this data is lost if there's a crash so a safe fallback
+value should always be possible.
+
+For instance, the 'mq' policy, which is currently the default policy,
+uses this facility to store the hit count of the cache blocks. If
+there's a crash this information will be lost, which means the cache
+may be less efficient until those hit counts are regenerated.
+
+Policy hints affect performance, not correctness.
+
+Policy messaging
+----------------
+
+Policies will have different tunables, specific to each one, so we
+need a generic way of getting and setting these. Device-mapper
+messages are used. Refer to cache-policies.txt.
+
+Discard bitset resolution
+-------------------------
+
+We can avoid copying data during migration if we know the block has
+been discarded. A prime example of this is when mkfs discards the
+whole block device. We store a bitset tracking the discard state of
+blocks. However, we allow this bitset to have a different block size
+from the cache blocks. This is because we need to track the discard
+state for all of the origin device (compare with the dirty bitset
+which is just for the smaller cache device).
+
+Target interface
+================
+
+Constructor
+-----------
+
+ cache <metadata dev> <cache dev> <origin dev> <block size>
+ <#feature args> [<feature arg>]*
+ <policy> <#policy args> [policy args]*
+
+ metadata dev : fast device holding the persistent metadata
+ cache dev : fast device holding cached data blocks
+ origin dev : slow device holding original data blocks
+ block size : cache unit size in sectors
+
+ #feature args : number of feature arguments passed
+ feature args : writethrough. (The default is writeback.)
+
+ policy : the replacement policy to use
+ #policy args : an even number of arguments corresponding to
+ key/value pairs passed to the policy
+ policy args : key/value pairs passed to the policy
+ E.g. 'sequential_threshold 1024'
+ See cache-policies.txt for details.
+
+Optional feature arguments are:
+ writethrough : write through caching that prohibits cache block
+ content from being different from origin block content.
+ Without this argument, the default behaviour is to write
+ back cache block contents later for performance reasons,
+ so they may differ from the corresponding origin blocks.
+
+A policy called 'default' is always registered. This is an alias for
+the policy we currently think is giving best all round performance.
+
+As the default policy could vary between kernels, if you are relying on
+the characteristics of a specific policy, always request it by name.
+
+Status
+------
+
+<#used metadata blocks>/<#total metadata blocks> <#read hits> <#read misses>
+<#write hits> <#write misses> <#demotions> <#promotions> <#blocks in cache>
+<#dirty> <#features> <features>* <#core args> <core args>* <#policy args>
+<policy args>*
+
+#used metadata blocks : Number of metadata blocks used
+#total metadata blocks : Total number of metadata blocks
+#read hits : Number of times a READ bio has been mapped
+ to the cache
+#read misses : Number of times a READ bio has been mapped
+ to the origin
+#write hits : Number of times a WRITE bio has been mapped
+ to the cache
+#write misses : Number of times a WRITE bio has been
+ mapped to the origin
+#demotions : Number of times a block has been removed
+ from the cache
+#promotions : Number of times a block has been moved to
+ the cache
+#blocks in cache : Number of blocks resident in the cache
+#dirty : Number of blocks in the cache that differ
+ from the origin
+#feature args : Number of feature args to follow
+feature args : 'writethrough' (optional)
+#core args : Number of core arguments (must be even)
+core args : Key/value pairs for tuning the core
+ e.g. migration_threshold
+#policy args : Number of policy arguments to follow (must be even)
+policy args : Key/value pairs
+ e.g. 'sequential_threshold 1024
+
+Messages
+--------
+
+Policies will have different tunables, specific to each one, so we
+need a generic way of getting and setting these. Device-mapper
+messages are used. (A sysfs interface would also be possible.)
+
+The message format is:
+
+ <key> <value>
+
+E.g.
+ dmsetup message my_cache 0 sequential_threshold 1024
+
+Examples
+========
+
+The test suite can be found here:
+
+https://github.com/jthornber/thinp-test-suite
+
+dmsetup create my_cache --table '0 41943040 cache /dev/mapper/metadata \
+ /dev/mapper/ssd /dev/mapper/origin 512 1 writeback default 0'
+dmsetup create my_cache --table '0 41943040 cache /dev/mapper/metadata \
+ /dev/mapper/ssd /dev/mapper/origin 1024 1 writeback \
+ mq 4 sequential_threshold 1024 random_threshold 8'
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 91a02ee..e30b490 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -210,7 +210,7 @@ config DM_DEBUG
config DM_BUFIO
tristate
- depends on BLK_DEV_DM && EXPERIMENTAL
+ depends on BLK_DEV_DM
---help---
This interface allows you to do buffered I/O on a device and acts
as a cache, holding recently-read blocks in memory and performing
@@ -218,7 +218,7 @@ config DM_BUFIO
config DM_BIO_PRISON
tristate
- depends on BLK_DEV_DM && EXPERIMENTAL
+ depends on BLK_DEV_DM
---help---
Some bio locking schemes used by other device-mapper targets
including thin provisioning.
@@ -251,8 +251,8 @@ config DM_SNAPSHOT
Allow volume managers to take writable snapshots of a device.
config DM_THIN_PROVISIONING
- tristate "Thin provisioning target (EXPERIMENTAL)"
- depends on BLK_DEV_DM && EXPERIMENTAL
+ tristate "Thin provisioning target"
+ depends on BLK_DEV_DM
select DM_PERSISTENT_DATA
select DM_BIO_PRISON
---help---
@@ -268,6 +268,37 @@ config DM_DEBUG_BLOCK_STACK_TRACING
If unsure, say N.
+config DM_CACHE
+ tristate "Cache target (EXPERIMENTAL)"
+ depends on BLK_DEV_DM
+ default n
+ select DM_PERSISTENT_DATA
+ select DM_BIO_PRISON
+ ---help---
+ dm-cache attempts to improve performance of a block device by
+ moving frequently used data to a smaller, higher performance
+ device. Different 'policy' plugins can be used to change the
+ algorithms used to select which blocks are promoted, demoted,
+ cleaned etc. It supports writeback and writethrough modes.
+
+config DM_CACHE_MQ
+ tristate "MQ Cache Policy (EXPERIMENTAL)"
+ depends on DM_CACHE
+ default y
+ ---help---
+ A cache policy that uses a multiqueue ordered by recent hit
+ count to select which blocks should be promoted and demoted.
+ This is meant to be a general purpose policy. It prioritises
+ reads over writes.
+
+config DM_CACHE_CLEANER
+ tristate "Cleaner Cache Policy (EXPERIMENTAL)"
+ depends on DM_CACHE
+ default y
+ ---help---
+ A simple cache policy that writes back all data to the
+ origin. Used when decommissioning a dm-cache.
+
config DM_MIRROR
tristate "Mirror target"
depends on BLK_DEV_DM
@@ -302,8 +333,8 @@ config DM_RAID
in one of the available parity distribution methods.
config DM_LOG_USERSPACE
- tristate "Mirror userspace logging (EXPERIMENTAL)"
- depends on DM_MIRROR && EXPERIMENTAL && NET
+ tristate "Mirror userspace logging"
+ depends on DM_MIRROR && NET
select CONNECTOR
---help---
The userspace logging module provides a mechanism for
@@ -350,8 +381,8 @@ config DM_MULTIPATH_ST
If unsure, say N.
config DM_DELAY
- tristate "I/O delaying target (EXPERIMENTAL)"
- depends on BLK_DEV_DM && EXPERIMENTAL
+ tristate "I/O delaying target"
+ depends on BLK_DEV_DM
---help---
A target that delays reads and/or writes and can send
them to different devices. Useful for testing.
@@ -365,14 +396,14 @@ config DM_UEVENT
Generate udev events for DM events.
config DM_FLAKEY
- tristate "Flakey target (EXPERIMENTAL)"
- depends on BLK_DEV_DM && EXPERIMENTAL
+ tristate "Flakey target"
+ depends on BLK_DEV_DM
---help---
A target that intermittently fails I/O for debugging purposes.
config DM_VERITY
- tristate "Verity target support (EXPERIMENTAL)"
- depends on BLK_DEV_DM && EXPERIMENTAL
+ tristate "Verity target support"
+ depends on BLK_DEV_DM
select CRYPTO
select CRYPTO_HASH
select DM_BUFIO
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 94dce8b..7ceeaef 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -11,6 +11,9 @@ dm-mirror-y += dm-raid1.o
dm-log-userspace-y \
+= dm-log-userspace-base.o dm-log-userspace-transfer.o
dm-thin-pool-y += dm-thin.o dm-thin-metadata.o
+dm-cache-y += dm-cache-target.o dm-cache-metadata.o dm-cache-policy.o
+dm-cache-mq-y += dm-cache-policy-mq.o
+dm-cache-cleaner-y += dm-cache-policy-cleaner.o
md-mod-y += md.o bitmap.o
raid456-y += raid5.o
@@ -44,6 +47,9 @@ obj-$(CONFIG_DM_ZERO) += dm-zero.o
obj-$(CONFIG_DM_RAID) += dm-raid.o
obj-$(CONFIG_DM_THIN_PROVISIONING) += dm-thin-pool.o
obj-$(CONFIG_DM_VERITY) += dm-verity.o
+obj-$(CONFIG_DM_CACHE) += dm-cache.o
+obj-$(CONFIG_DM_CACHE_MQ) += dm-cache-mq.o
+obj-$(CONFIG_DM_CACHE_CLEANER) += dm-cache-cleaner.o
ifeq ($(CONFIG_DM_UEVENT),y)
dm-mod-objs += dm-uevent.o
diff --git a/drivers/md/dm-bio-prison.c b/drivers/md/dm-bio-prison.c
index d9d3f1c..85f0b70 100644
--- a/drivers/md/dm-bio-prison.c
+++ b/drivers/md/dm-bio-prison.c
@@ -14,14 +14,6 @@
/*----------------------------------------------------------------*/
-struct dm_bio_prison_cell {
- struct hlist_node list;
- struct dm_bio_prison *prison;
- struct dm_cell_key key;
- struct bio *holder;
- struct bio_list bios;
-};
-
struct dm_bio_prison {
spinlock_t lock;
mempool_t *cell_pool;
@@ -87,6 +79,19 @@ void dm_bio_prison_destroy(struct dm_bio_prison *prison)
}
EXPORT_SYMBOL_GPL(dm_bio_prison_destroy);
+struct dm_bio_prison_cell *dm_bio_prison_alloc_cell(struct dm_bio_prison *prison, gfp_t gfp)
+{
+ return mempool_alloc(prison->cell_pool, gfp);
+}
+EXPORT_SYMBOL_GPL(dm_bio_prison_alloc_cell);
+
+void dm_bio_prison_free_cell(struct dm_bio_prison *prison,
+ struct dm_bio_prison_cell *cell)
+{
+ mempool_free(cell, prison->cell_pool);
+}
+EXPORT_SYMBOL_GPL(dm_bio_prison_free_cell);
+
static uint32_t hash_key(struct dm_bio_prison *prison, struct dm_cell_key *key)
{
const unsigned long BIG_PRIME = 4294967291UL;
@@ -114,91 +119,95 @@ static struct dm_bio_prison_cell *__search_bucket(struct hlist_head *bucket,
return NULL;
}
-/*
- * This may block if a new cell needs allocating. You must ensure that
- * cells will be unlocked even if the calling thread is blocked.
- *
- * Returns 1 if the cell was already held, 0 if @inmate is the new holder.
- */
-int dm_bio_detain(struct dm_bio_prison *prison, struct dm_cell_key *key,
- struct bio *inmate, struct dm_bio_prison_cell **ref)
+static void __setup_new_cell(struct dm_bio_prison *prison,
+ struct dm_cell_key *key,
+ struct bio *holder,
+ uint32_t hash,
+ struct dm_bio_prison_cell *cell)
{
- int r = 1;
- unsigned long flags;
- uint32_t hash = hash_key(prison, key);
- struct dm_bio_prison_cell *cell, *cell2;
-
- BUG_ON(hash > prison->nr_buckets);
-
- spin_lock_irqsave(&prison->lock, flags);
-
- cell = __search_bucket(prison->cells + hash, key);
- if (cell) {
- bio_list_add(&cell->bios, inmate);
- goto out;
- }
+ memcpy(&cell->key, key, sizeof(cell->key));
+ cell->holder = holder;
+ bio_list_init(&cell->bios);
+ hlist_add_head(&cell->list, prison->cells + hash);
+}
- /*
- * Allocate a new cell
- */
- spin_unlock_irqrestore(&prison->lock, flags);
- cell2 = mempool_alloc(prison->cell_pool, GFP_NOIO);
- spin_lock_irqsave(&prison->lock, flags);
+static int __bio_detain(struct dm_bio_prison *prison,
+ struct dm_cell_key *key,
+ struct bio *inmate,
+ struct dm_bio_prison_cell *cell_prealloc,
+ struct dm_bio_prison_cell **cell_result)
+{
+ uint32_t hash = hash_key(prison, key);
+ struct dm_bio_prison_cell *cell;
- /*
- * We've been unlocked, so we have to double check that
- * nobody else has inserted this cell in the meantime.
- */
cell = __search_bucket(prison->cells + hash, key);
if (cell) {
- mempool_free(cell2, prison->cell_pool);
- bio_list_add(&cell->bios, inmate);
- goto out;
+ if (inmate)
+ bio_list_add(&cell->bios, inmate);
+ *cell_result = cell;
+ return 1;
}
- /*
- * Use new cell.
- */
- cell = cell2;
-
- cell->prison = prison;
- memcpy(&cell->key, key, sizeof(cell->key));
- cell->holder = inmate;
- bio_list_init(&cell->bios);
- hlist_add_head(&cell->list, prison->cells + hash);
+ __setup_new_cell(prison, key, inmate, hash, cell_prealloc);
+ *cell_result = cell_prealloc;
+ return 0;
+}
- r = 0;
+static int bio_detain(struct dm_bio_prison *prison,
+ struct dm_cell_key *key,
+ struct bio *inmate,
+ struct dm_bio_prison_cell *cell_prealloc,
+ struct dm_bio_prison_cell **cell_result)
+{
+ int r;
+ unsigned long flags;
-out:
+ spin_lock_irqsave(&prison->lock, flags);
+ r = __bio_detain(prison, key, inmate, cell_prealloc, cell_result);
spin_unlock_irqrestore(&prison->lock, flags);
- *ref = cell;
-
return r;
}
+
+int dm_bio_detain(struct dm_bio_prison *prison,
+ struct dm_cell_key *key,
+ struct bio *inmate,
+ struct dm_bio_prison_cell *cell_prealloc,
+ struct dm_bio_prison_cell **cell_result)
+{
+ return bio_detain(prison, key, inmate, cell_prealloc, cell_result);
+}
EXPORT_SYMBOL_GPL(dm_bio_detain);
+int dm_get_cell(struct dm_bio_prison *prison,
+ struct dm_cell_key *key,
+ struct dm_bio_prison_cell *cell_prealloc,
+ struct dm_bio_prison_cell **cell_result)
+{
+ return bio_detain(prison, key, NULL, cell_prealloc, cell_result);
+}
+EXPORT_SYMBOL_GPL(dm_get_cell);
+
/*
* @inmates must have been initialised prior to this call
*/
-static void __cell_release(struct dm_bio_prison_cell *cell, struct bio_list *inmates)
+static void __cell_release(struct dm_bio_prison_cell *cell,
+ struct bio_list *inmates)
{
- struct dm_bio_prison *prison = cell->prison;
-
hlist_del(&cell->list);
if (inmates) {
- bio_list_add(inmates, cell->holder);
+ if (cell->holder)
+ bio_list_add(inmates, cell->holder);
bio_list_merge(inmates, &cell->bios);
}
-
- mempool_free(cell, prison->cell_pool);
}
-void dm_cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios)
+void dm_cell_release(struct dm_bio_prison *prison,
+ struct dm_bio_prison_cell *cell,
+ struct bio_list *bios)
{
unsigned long flags;
- struct dm_bio_prison *prison = cell->prison;
spin_lock_irqsave(&prison->lock, flags);
__cell_release(cell, bios);
@@ -209,20 +218,18 @@ EXPORT_SYMBOL_GPL(dm_cell_release);
/*
* Sometimes we don't want the holder, just the additional bios.
*/
-static void __cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates)
+static void __cell_release_no_holder(struct dm_bio_prison_cell *cell,
+ struct bio_list *inmates)
{
- struct dm_bio_prison *prison = cell->prison;
-
hlist_del(&cell->list);
bio_list_merge(inmates, &cell->bios);
-
- mempool_free(cell, prison->cell_pool);
}
-void dm_cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates)
+void dm_cell_release_no_holder(struct dm_bio_prison *prison,
+ struct dm_bio_prison_cell *cell,
+ struct bio_list *inmates)
{
unsigned long flags;
- struct dm_bio_prison *prison = cell->prison;
spin_lock_irqsave(&prison->lock, flags);
__cell_release_no_holder(cell, inmates);
@@ -230,9 +237,9 @@ void dm_cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list
}
EXPORT_SYMBOL_GPL(dm_cell_release_no_holder);
-void dm_cell_error(struct dm_bio_prison_cell *cell)
+void dm_cell_error(struct dm_bio_prison *prison,
+ struct dm_bio_prison_cell *cell)
{
- struct dm_bio_prison *prison = cell->prison;
struct bio_list bios;
struct bio *bio;
unsigned long flags;
diff --git a/drivers/md/dm-bio-prison.h b/drivers/md/dm-bio-prison.h
index 53d1a7a..3f83319 100644
--- a/drivers/md/dm-bio-prison.h
+++ b/drivers/md/dm-bio-prison.h
@@ -22,7 +22,6 @@
* subsequently unlocked the bios become available.
*/
struct dm_bio_prison;
-struct dm_bio_prison_cell;
/* FIXME: this needs to be more abstract */
struct dm_cell_key {
@@ -31,21 +30,62 @@ struct dm_cell_key {
dm_block_t block;
};
+/*
+ * Treat this as opaque, only in header so callers can manage allocation
+ * themselves.
+ */
+struct dm_bio_prison_cell {
+ struct hlist_node list;
+ struct dm_cell_key key;
+ struct bio *holder;
+ struct bio_list bios;
+};
+
struct dm_bio_prison *dm_bio_prison_create(unsigned nr_cells);
void dm_bio_prison_destroy(struct dm_bio_prison *prison);
/*
- * This may block if a new cell needs allocating. You must ensure that
- * cells will be unlocked even if the calling thread is blocked.
+ * These two functions just wrap a mempool. This is a transitory step:
+ * Eventually all bio prison clients should manage their own cell memory.
*
- * Returns 1 if the cell was already held, 0 if @inmate is the new holder.
+ * Like mempool_alloc(), dm_bio_prison_alloc_cell() can only fail if called
+ * in interrupt context or passed GFP_NOWAIT.
*/
-int dm_bio_detain(struct dm_bio_prison *prison, struct dm_cell_key *key,
- struct bio *inmate, struct dm_bio_prison_cell **ref);
+struct dm_bio_prison_cell *dm_bio_prison_alloc_cell(struct dm_bio_prison *prison,
+ gfp_t gfp);
+void dm_bio_prison_free_cell(struct dm_bio_prison *prison,
+ struct dm_bio_prison_cell *cell);
-void dm_cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios);
-void dm_cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates);
-void dm_cell_error(struct dm_bio_prison_cell *cell);
+/*
+ * Creates, or retrieves a cell for the given key.
+ *
+ * Returns 1 if pre-existing cell returned, zero if new cell created using
+ * @cell_prealloc.
+ */
+int dm_get_cell(struct dm_bio_prison *prison,
+ struct dm_cell_key *key,
+ struct dm_bio_prison_cell *cell_prealloc,
+ struct dm_bio_prison_cell **cell_result);
+
+/*
+ * An atomic op that combines retrieving a cell, and adding a bio to it.
+ *
+ * Returns 1 if the cell was already held, 0 if @inmate is the new holder.
+ */
+int dm_bio_detain(struct dm_bio_prison *prison,
+ struct dm_cell_key *key,
+ struct bio *inmate,
+ struct dm_bio_prison_cell *cell_prealloc,
+ struct dm_bio_prison_cell **cell_result);
+
+void dm_cell_release(struct dm_bio_prison *prison,
+ struct dm_bio_prison_cell *cell,
+ struct bio_list *bios);
+void dm_cell_release_no_holder(struct dm_bio_prison *prison,
+ struct dm_bio_prison_cell *cell,
+ struct bio_list *inmates);
+void dm_cell_error(struct dm_bio_prison *prison,
+ struct dm_bio_prison_cell *cell);
/*----------------------------------------------------------------*/
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 93205e3..3c955e1 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -1192,7 +1192,7 @@ EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers);
int dm_bufio_issue_flush(struct dm_bufio_client *c)
{
struct dm_io_request io_req = {
- .bi_rw = REQ_FLUSH,
+ .bi_rw = WRITE_FLUSH,
.mem.type = DM_IO_KMEM,
.mem.ptr.addr = NULL,
.client = c->dm_io,
diff --git a/drivers/md/dm-cache-block-types.h b/drivers/md/dm-cache-block-types.h
new file mode 100644
index 0000000..bed4ad4
--- /dev/null
+++ b/drivers/md/dm-cache-block-types.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef DM_CACHE_BLOCK_TYPES_H
+#define DM_CACHE_BLOCK_TYPES_H
+
+#include "persistent-data/dm-block-manager.h"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * It's helpful to get sparse to differentiate between indexes into the
+ * origin device, indexes into the cache device, and indexes into the
+ * discard bitset.
+ */
+
+typedef dm_block_t __bitwise__ dm_oblock_t;
+typedef uint32_t __bitwise__ dm_cblock_t;
+typedef dm_block_t __bitwise__ dm_dblock_t;
+
+static inline dm_oblock_t to_oblock(dm_block_t b)
+{
+ return (__force dm_oblock_t) b;
+}
+
+static inline dm_block_t from_oblock(dm_oblock_t b)
+{
+ return (__force dm_block_t) b;
+}
+
+static inline dm_cblock_t to_cblock(uint32_t b)
+{
+ return (__force dm_cblock_t) b;
+}
+
+static inline uint32_t from_cblock(dm_cblock_t b)
+{
+ return (__force uint32_t) b;
+}
+
+static inline dm_dblock_t to_dblock(dm_block_t b)
+{
+ return (__force dm_dblock_t) b;
+}
+
+static inline dm_block_t from_dblock(dm_dblock_t b)
+{
+ return (__force dm_block_t) b;
+}
+
+#endif /* DM_CACHE_BLOCK_TYPES_H */
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
new file mode 100644
index 0000000..fbd3625
--- /dev/null
+++ b/drivers/md/dm-cache-metadata.c
@@ -0,0 +1,1146 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-cache-metadata.h"
+
+#include "persistent-data/dm-array.h"
+#include "persistent-data/dm-bitset.h"
+#include "persistent-data/dm-space-map.h"
+#include "persistent-data/dm-space-map-disk.h"
+#include "persistent-data/dm-transaction-manager.h"
+
+#include <linux/device-mapper.h>
+
+/*----------------------------------------------------------------*/
+
+#define DM_MSG_PREFIX "cache metadata"
+
+#define CACHE_SUPERBLOCK_MAGIC 06142003
+#define CACHE_SUPERBLOCK_LOCATION 0
+#define CACHE_VERSION 1
+#define CACHE_METADATA_CACHE_SIZE 64
+
+/*
+ * 3 for btree insert +
+ * 2 for btree lookup used within space map
+ */
+#define CACHE_MAX_CONCURRENT_LOCKS 5
+#define SPACE_MAP_ROOT_SIZE 128
+
+enum superblock_flag_bits {
+ /* for spotting crashes that would invalidate the dirty bitset */
+ CLEAN_SHUTDOWN,
+};
+
+/*
+ * Each mapping from cache block -> origin block carries a set of flags.
+ */
+enum mapping_bits {
+ /*
+ * A valid mapping. Because we're using an array we clear this
+ * flag for an non existant mapping.
+ */
+ M_VALID = 1,
+
+ /*
+ * The data on the cache is different from that on the origin.
+ */
+ M_DIRTY = 2
+};
+
+struct cache_disk_superblock {
+ __le32 csum;
+ __le32 flags;
+ __le64 blocknr;
+
+ __u8 uuid[16];
+ __le64 magic;
+ __le32 version;
+
+ __u8 policy_name[CACHE_POLICY_NAME_SIZE];
+ __le32 policy_hint_size;
+
+ __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
+ __le64 mapping_root;
+ __le64 hint_root;
+
+ __le64 discard_root;
+ __le64 discard_block_size;
+ __le64 discard_nr_blocks;
+
+ __le32 data_block_size;
+ __le32 metadata_block_size;
+ __le32 cache_blocks;
+
+ __le32 compat_flags;
+ __le32 compat_ro_flags;
+ __le32 incompat_flags;
+
+ __le32 read_hits;
+ __le32 read_misses;
+ __le32 write_hits;
+ __le32 write_misses;
+} __packed;
+
+struct dm_cache_metadata {
+ struct block_device *bdev;
+ struct dm_block_manager *bm;
+ struct dm_space_map *metadata_sm;
+ struct dm_transaction_manager *tm;
+
+ struct dm_array_info info;
+ struct dm_array_info hint_info;
+ struct dm_disk_bitset discard_info;
+
+ struct rw_semaphore root_lock;
+ dm_block_t root;
+ dm_block_t hint_root;
+ dm_block_t discard_root;
+
+ sector_t discard_block_size;
+ dm_dblock_t discard_nr_blocks;
+
+ sector_t data_block_size;
+ dm_cblock_t cache_blocks;
+ bool changed:1;
+ bool clean_when_opened:1;
+
+ char policy_name[CACHE_POLICY_NAME_SIZE];
+ size_t policy_hint_size;
+ struct dm_cache_statistics stats;
+};
+
+/*-------------------------------------------------------------------
+ * superblock validator
+ *-----------------------------------------------------------------*/
+
+#define SUPERBLOCK_CSUM_XOR 9031977
+
+static void sb_prepare_for_write(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t sb_block_size)
+{
+ struct cache_disk_superblock *disk_super = dm_block_data(b);
+
+ disk_super->blocknr = cpu_to_le64(dm_block_location(b));
+ disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
+ sb_block_size - sizeof(__le32),
+ SUPERBLOCK_CSUM_XOR));
+}
+
+static int sb_check(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t sb_block_size)
+{
+ struct cache_disk_superblock *disk_super = dm_block_data(b);
+ __le32 csum_le;
+
+ if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
+ DMERR("sb_check failed: blocknr %llu: wanted %llu",
+ le64_to_cpu(disk_super->blocknr),
+ (unsigned long long)dm_block_location(b));
+ return -ENOTBLK;
+ }
+
+ if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
+ DMERR("sb_check failed: magic %llu: wanted %llu",
+ le64_to_cpu(disk_super->magic),
+ (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
+ return -EILSEQ;
+ }
+
+ csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
+ sb_block_size - sizeof(__le32),
+ SUPERBLOCK_CSUM_XOR));
+ if (csum_le != disk_super->csum) {
+ DMERR("sb_check failed: csum %u: wanted %u",
+ le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
+ return -EILSEQ;
+ }
+
+ return 0;
+}
+
+static struct dm_block_validator sb_validator = {
+ .name = "superblock",
+ .prepare_for_write = sb_prepare_for_write,
+ .check = sb_check
+};
+
+/*----------------------------------------------------------------*/
+
+static int superblock_read_lock(struct dm_cache_metadata *cmd,
+ struct dm_block **sblock)
+{
+ return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
+ &sb_validator, sblock);
+}
+
+static int superblock_lock_zero(struct dm_cache_metadata *cmd,
+ struct dm_block **sblock)
+{
+ return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
+ &sb_validator, sblock);
+}
+
+static int superblock_lock(struct dm_cache_metadata *cmd,
+ struct dm_block **sblock)
+{
+ return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
+ &sb_validator, sblock);
+}
+
+/*----------------------------------------------------------------*/
+
+static int __superblock_all_zeroes(struct dm_block_manager *bm, int *result)
+{
+ int r;
+ unsigned i;
+ struct dm_block *b;
+ __le64 *data_le, zero = cpu_to_le64(0);
+ unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
+
+ /*
+ * We can't use a validator here - it may be all zeroes.
+ */
+ r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
+ if (r)
+ return r;
+
+ data_le = dm_block_data(b);
+ *result = 1;
+ for (i = 0; i < sb_block_size; i++) {
+ if (data_le[i] != zero) {
+ *result = 0;
+ break;
+ }
+ }
+
+ return dm_bm_unlock(b);
+}
+
+static void __setup_mapping_info(struct dm_cache_metadata *cmd)
+{
+ struct dm_btree_value_type vt;
+
+ vt.context = NULL;
+ vt.size = sizeof(__le64);
+ vt.inc = NULL;
+ vt.dec = NULL;
+ vt.equal = NULL;
+ dm_array_info_init(&cmd->info, cmd->tm, &vt);
+
+ if (cmd->policy_hint_size) {
+ vt.size = sizeof(__le32);
+ dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
+ }
+}
+
+static int __write_initial_superblock(struct dm_cache_metadata *cmd)
+{
+ int r;
+ struct dm_block *sblock;
+ size_t metadata_len;
+ struct cache_disk_superblock *disk_super;
+ sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
+
+ /* FIXME: see if we can lose the max sectors limit */
+ if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
+ bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
+
+ r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
+ if (r < 0)
+ return r;
+
+ r = dm_tm_pre_commit(cmd->tm);
+ if (r < 0)
+ return r;
+
+ r = superblock_lock_zero(cmd, &sblock);
+ if (r)
+ return r;
+
+ disk_super = dm_block_data(sblock);
+ disk_super->flags = 0;
+ memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
+ disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
+ disk_super->version = cpu_to_le32(CACHE_VERSION);
+ memset(disk_super->policy_name, 0, CACHE_POLICY_NAME_SIZE);
+ disk_super->policy_hint_size = 0;
+
+ r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root,
+ metadata_len);
+ if (r < 0)
+ goto bad_locked;
+
+ disk_super->mapping_root = cpu_to_le64(cmd->root);
+ disk_super->hint_root = cpu_to_le64(cmd->hint_root);
+ disk_super->discard_root = cpu_to_le64(cmd->discard_root);
+ disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
+ disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
+ disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
+ disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
+ disk_super->cache_blocks = cpu_to_le32(0);
+ memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
+
+ disk_super->read_hits = cpu_to_le32(0);
+ disk_super->read_misses = cpu_to_le32(0);
+ disk_super->write_hits = cpu_to_le32(0);
+ disk_super->write_misses = cpu_to_le32(0);
+
+ return dm_tm_commit(cmd->tm, sblock);
+
+bad_locked:
+ dm_bm_unlock(sblock);
+ return r;
+}
+
+static int __format_metadata(struct dm_cache_metadata *cmd)
+{
+ int r;
+
+ r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
+ &cmd->tm, &cmd->metadata_sm);
+ if (r < 0) {
+ DMERR("tm_create_with_sm failed");
+ return r;
+ }
+
+ __setup_mapping_info(cmd);
+
+ r = dm_array_empty(&cmd->info, &cmd->root);
+ if (r < 0)
+ goto bad;
+
+ dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
+
+ r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
+ if (r < 0)
+ goto bad;
+
+ cmd->discard_block_size = 0;
+ cmd->discard_nr_blocks = 0;
+
+ r = __write_initial_superblock(cmd);
+ if (r)
+ goto bad;
+
+ cmd->clean_when_opened = true;
+ return 0;
+
+bad:
+ dm_tm_destroy(cmd->tm);
+ dm_sm_destroy(cmd->metadata_sm);
+
+ return r;
+}
+
+static int __check_incompat_features(struct cache_disk_superblock *disk_super,
+ struct dm_cache_metadata *cmd)
+{
+ uint32_t features;
+
+ features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
+ if (features) {
+ DMERR("could not access metadata due to unsupported optional features (%lx).",
+ (unsigned long)features);
+ return -EINVAL;
+ }
+
+ /*
+ * Check for read-only metadata to skip the following RDWR checks.
+ */
+ if (get_disk_ro(cmd->bdev->bd_disk))
+ return 0;
+
+ features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
+ if (features) {
+ DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
+ (unsigned long)features);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int __open_metadata(struct dm_cache_metadata *cmd)
+{
+ int r;
+ struct dm_block *sblock;
+ struct cache_disk_superblock *disk_super;
+ unsigned long sb_flags;
+
+ r = superblock_read_lock(cmd, &sblock);
+ if (r < 0) {
+ DMERR("couldn't read lock superblock");
+ return r;
+ }
+
+ disk_super = dm_block_data(sblock);
+
+ r = __check_incompat_features(disk_super, cmd);
+ if (r < 0)
+ goto bad;
+
+ r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
+ disk_super->metadata_space_map_root,
+ sizeof(disk_super->metadata_space_map_root),
+ &cmd->tm, &cmd->metadata_sm);
+ if (r < 0) {
+ DMERR("tm_open_with_sm failed");
+ goto bad;
+ }
+
+ __setup_mapping_info(cmd);
+ dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
+ sb_flags = le32_to_cpu(disk_super->flags);
+ cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
+ return dm_bm_unlock(sblock);
+
+bad:
+ dm_bm_unlock(sblock);
+ return r;
+}
+
+static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
+ bool format_device)
+{
+ int r, unformatted;
+
+ r = __superblock_all_zeroes(cmd->bm, &unformatted);
+ if (r)
+ return r;
+
+ if (unformatted)
+ return format_device ? __format_metadata(cmd) : -EPERM;
+
+ return __open_metadata(cmd);
+}
+
+static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
+ bool may_format_device)
+{
+ int r;
+ cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE,
+ CACHE_METADATA_CACHE_SIZE,
+ CACHE_MAX_CONCURRENT_LOCKS);
+ if (IS_ERR(cmd->bm)) {
+ DMERR("could not create block manager");
+ return PTR_ERR(cmd->bm);
+ }
+
+ r = __open_or_format_metadata(cmd, may_format_device);
+ if (r)
+ dm_block_manager_destroy(cmd->bm);
+
+ return r;
+}
+
+static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
+{
+ dm_sm_destroy(cmd->metadata_sm);
+ dm_tm_destroy(cmd->tm);
+ dm_block_manager_destroy(cmd->bm);
+}
+
+typedef unsigned long (*flags_mutator)(unsigned long);
+
+static void update_flags(struct cache_disk_superblock *disk_super,
+ flags_mutator mutator)
+{
+ uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
+ disk_super->flags = cpu_to_le32(sb_flags);
+}
+
+static unsigned long set_clean_shutdown(unsigned long flags)
+{
+ set_bit(CLEAN_SHUTDOWN, &flags);
+ return flags;
+}
+
+static unsigned long clear_clean_shutdown(unsigned long flags)
+{
+ clear_bit(CLEAN_SHUTDOWN, &flags);
+ return flags;
+}
+
+static void read_superblock_fields(struct dm_cache_metadata *cmd,
+ struct cache_disk_superblock *disk_super)
+{
+ cmd->root = le64_to_cpu(disk_super->mapping_root);
+ cmd->hint_root = le64_to_cpu(disk_super->hint_root);
+ cmd->discard_root = le64_to_cpu(disk_super->discard_root);
+ cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
+ cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
+ cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
+ cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
+ strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
+ cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
+
+ cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
+ cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
+ cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
+ cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
+
+ cmd->changed = false;
+}
+
+/*
+ * The mutator updates the superblock flags.
+ */
+static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
+ flags_mutator mutator)
+{
+ int r;
+ struct cache_disk_superblock *disk_super;
+ struct dm_block *sblock;
+
+ r = superblock_lock(cmd, &sblock);
+ if (r)
+ return r;
+
+ disk_super = dm_block_data(sblock);
+ update_flags(disk_super, mutator);
+ read_superblock_fields(cmd, disk_super);
+
+ return dm_bm_flush_and_unlock(cmd->bm, sblock);
+}
+
+static int __begin_transaction(struct dm_cache_metadata *cmd)
+{
+ int r;
+ struct cache_disk_superblock *disk_super;
+ struct dm_block *sblock;
+
+ /*
+ * We re-read the superblock every time. Shouldn't need to do this
+ * really.
+ */
+ r = superblock_read_lock(cmd, &sblock);
+ if (r)
+ return r;
+
+ disk_super = dm_block_data(sblock);
+ read_superblock_fields(cmd, disk_super);
+ dm_bm_unlock(sblock);
+
+ return 0;
+}
+
+static int __commit_transaction(struct dm_cache_metadata *cmd,
+ flags_mutator mutator)
+{
+ int r;
+ size_t metadata_len;
+ struct cache_disk_superblock *disk_super;
+ struct dm_block *sblock;
+
+ /*
+ * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
+ */
+ BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
+
+ r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
+ &cmd->discard_root);
+ if (r)
+ return r;
+
+ r = dm_tm_pre_commit(cmd->tm);
+ if (r < 0)
+ return r;
+
+ r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
+ if (r < 0)
+ return r;
+
+ r = superblock_lock(cmd, &sblock);
+ if (r)
+ return r;
+
+ disk_super = dm_block_data(sblock);
+
+ if (mutator)
+ update_flags(disk_super, mutator);
+
+ disk_super->mapping_root = cpu_to_le64(cmd->root);
+ disk_super->hint_root = cpu_to_le64(cmd->hint_root);
+ disk_super->discard_root = cpu_to_le64(cmd->discard_root);
+ disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
+ disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
+ disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
+ strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
+
+ disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
+ disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
+ disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
+ disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
+
+ r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root,
+ metadata_len);
+ if (r < 0) {
+ dm_bm_unlock(sblock);
+ return r;
+ }
+
+ return dm_tm_commit(cmd->tm, sblock);
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * The mappings are held in a dm-array that has 64-bit values stored in
+ * little-endian format. The index is the cblock, the high 48bits of the
+ * value are the oblock and the low 16 bit the flags.
+ */
+#define FLAGS_MASK ((1 << 16) - 1)
+
+static __le64 pack_value(dm_oblock_t block, unsigned flags)
+{
+ uint64_t value = from_oblock(block);
+ value <<= 16;
+ value = value | (flags & FLAGS_MASK);
+ return cpu_to_le64(value);
+}
+
+static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
+{
+ uint64_t value = le64_to_cpu(value_le);
+ uint64_t b = value >> 16;
+ *block = to_oblock(b);
+ *flags = value & FLAGS_MASK;
+}
+
+/*----------------------------------------------------------------*/
+
+struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
+ sector_t data_block_size,
+ bool may_format_device,
+ size_t policy_hint_size)
+{
+ int r;
+ struct dm_cache_metadata *cmd;
+
+ cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
+ if (!cmd) {
+ DMERR("could not allocate metadata struct");
+ return NULL;
+ }
+
+ init_rwsem(&cmd->root_lock);
+ cmd->bdev = bdev;
+ cmd->data_block_size = data_block_size;
+ cmd->cache_blocks = 0;
+ cmd->policy_hint_size = policy_hint_size;
+ cmd->changed = true;
+
+ r = __create_persistent_data_objects(cmd, may_format_device);
+ if (r) {
+ kfree(cmd);
+ return ERR_PTR(r);
+ }
+
+ r = __begin_transaction_flags(cmd, clear_clean_shutdown);
+ if (r < 0) {
+ dm_cache_metadata_close(cmd);
+ return ERR_PTR(r);
+ }
+
+ return cmd;
+}
+
+void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
+{
+ __destroy_persistent_data_objects(cmd);
+ kfree(cmd);
+}
+
+int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
+{
+ int r;
+ __le64 null_mapping = pack_value(0, 0);
+
+ down_write(&cmd->root_lock);
+ __dm_bless_for_disk(&null_mapping);
+ r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
+ from_cblock(new_cache_size),
+ &null_mapping, &cmd->root);
+ if (!r)
+ cmd->cache_blocks = new_cache_size;
+ cmd->changed = true;
+ up_write(&cmd->root_lock);
+
+ return r;
+}
+
+int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
+ sector_t discard_block_size,
+ dm_dblock_t new_nr_entries)
+{
+ int r;
+
+ down_write(&cmd->root_lock);
+ r = dm_bitset_resize(&cmd->discard_info,
+ cmd->discard_root,
+ from_dblock(cmd->discard_nr_blocks),
+ from_dblock(new_nr_entries),
+ false, &cmd->discard_root);
+ if (!r) {
+ cmd->discard_block_size = discard_block_size;
+ cmd->discard_nr_blocks = new_nr_entries;
+ }
+
+ cmd->changed = true;
+ up_write(&cmd->root_lock);
+
+ return r;
+}
+
+static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
+{
+ return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
+ from_dblock(b), &cmd->discard_root);
+}
+
+static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
+{
+ return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
+ from_dblock(b), &cmd->discard_root);
+}
+
+static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b,
+ bool *is_discarded)
+{
+ return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
+ from_dblock(b), &cmd->discard_root,
+ is_discarded);
+}
+
+static int __discard(struct dm_cache_metadata *cmd,
+ dm_dblock_t dblock, bool discard)
+{
+ int r;
+
+ r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
+ if (r)
+ return r;
+
+ cmd->changed = true;
+ return 0;
+}
+
+int dm_cache_set_discard(struct dm_cache_metadata *cmd,
+ dm_dblock_t dblock, bool discard)
+{
+ int r;
+
+ down_write(&cmd->root_lock);
+ r = __discard(cmd, dblock, discard);
+ up_write(&cmd->root_lock);
+
+ return r;
+}
+
+static int __load_discards(struct dm_cache_metadata *cmd,
+ load_discard_fn fn, void *context)
+{
+ int r = 0;
+ dm_block_t b;
+ bool discard;
+
+ for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
+ dm_dblock_t dblock = to_dblock(b);
+
+ if (cmd->clean_when_opened) {
+ r = __is_discarded(cmd, dblock, &discard);
+ if (r)
+ return r;
+ } else
+ discard = false;
+
+ r = fn(context, cmd->discard_block_size, dblock, discard);
+ if (r)
+ break;
+ }
+
+ return r;
+}
+
+int dm_cache_load_discards(struct dm_cache_metadata *cmd,
+ load_discard_fn fn, void *context)
+{
+ int r;
+
+ down_read(&cmd->root_lock);
+ r = __load_discards(cmd, fn, context);
+ up_read(&cmd->root_lock);
+
+ return r;
+}
+
+dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd)
+{
+ dm_cblock_t r;
+
+ down_read(&cmd->root_lock);
+ r = cmd->cache_blocks;
+ up_read(&cmd->root_lock);
+
+ return r;
+}
+
+static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
+{
+ int r;
+ __le64 value = pack_value(0, 0);
+
+ __dm_bless_for_disk(&value);
+ r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
+ &value, &cmd->root);
+ if (r)
+ return r;
+
+ cmd->changed = true;
+ return 0;
+}
+
+int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
+{
+ int r;
+
+ down_write(&cmd->root_lock);
+ r = __remove(cmd, cblock);
+ up_write(&cmd->root_lock);
+
+ return r;
+}
+
+static int __insert(struct dm_cache_metadata *cmd,
+ dm_cblock_t cblock, dm_oblock_t oblock)
+{
+ int r;
+ __le64 value = pack_value(oblock, M_VALID);
+ __dm_bless_for_disk(&value);
+
+ r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
+ &value, &cmd->root);
+ if (r)
+ return r;
+
+ cmd->changed = true;
+ return 0;
+}
+
+int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
+ dm_cblock_t cblock, dm_oblock_t oblock)
+{
+ int r;
+
+ down_write(&cmd->root_lock);
+ r = __insert(cmd, cblock, oblock);
+ up_write(&cmd->root_lock);
+
+ return r;
+}
+
+struct thunk {
+ load_mapping_fn fn;
+ void *context;
+
+ struct dm_cache_metadata *cmd;
+ bool respect_dirty_flags;
+ bool hints_valid;
+};
+
+static bool hints_array_initialized(struct dm_cache_metadata *cmd)
+{
+ return cmd->hint_root && cmd->policy_hint_size;
+}
+
+static bool hints_array_available(struct dm_cache_metadata *cmd,
+ const char *policy_name)
+{
+ bool policy_names_match = !strncmp(cmd->policy_name, policy_name,
+ sizeof(cmd->policy_name));
+
+ return cmd->clean_when_opened && policy_names_match &&
+ hints_array_initialized(cmd);
+}
+
+static int __load_mapping(void *context, uint64_t cblock, void *leaf)
+{
+ int r = 0;
+ bool dirty;
+ __le64 value;
+ __le32 hint_value = 0;
+ dm_oblock_t oblock;
+ unsigned flags;
+ struct thunk *thunk = context;
+ struct dm_cache_metadata *cmd = thunk->cmd;
+
+ memcpy(&value, leaf, sizeof(value));
+ unpack_value(value, &oblock, &flags);
+
+ if (flags & M_VALID) {
+ if (thunk->hints_valid) {
+ r = dm_array_get_value(&cmd->hint_info, cmd->hint_root,
+ cblock, &hint_value);
+ if (r && r != -ENODATA)
+ return r;
+ }
+
+ dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true;
+ r = thunk->fn(thunk->context, oblock, to_cblock(cblock),
+ dirty, le32_to_cpu(hint_value), thunk->hints_valid);
+ }
+
+ return r;
+}
+
+static int __load_mappings(struct dm_cache_metadata *cmd, const char *policy_name,
+ load_mapping_fn fn, void *context)
+{
+ struct thunk thunk;
+
+ thunk.fn = fn;
+ thunk.context = context;
+
+ thunk.cmd = cmd;
+ thunk.respect_dirty_flags = cmd->clean_when_opened;
+ thunk.hints_valid = hints_array_available(cmd, policy_name);
+
+ return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk);
+}
+
+int dm_cache_load_mappings(struct dm_cache_metadata *cmd, const char *policy_name,
+ load_mapping_fn fn, void *context)
+{
+ int r;
+
+ down_read(&cmd->root_lock);
+ r = __load_mappings(cmd, policy_name, fn, context);
+ up_read(&cmd->root_lock);
+
+ return r;
+}
+
+static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
+{
+ int r = 0;
+ __le64 value;
+ dm_oblock_t oblock;
+ unsigned flags;
+
+ memcpy(&value, leaf, sizeof(value));
+ unpack_value(value, &oblock, &flags);
+
+ return r;
+}
+
+static int __dump_mappings(struct dm_cache_metadata *cmd)
+{
+ return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
+}
+
+void dm_cache_dump(struct dm_cache_metadata *cmd)
+{
+ down_read(&cmd->root_lock);
+ __dump_mappings(cmd);
+ up_read(&cmd->root_lock);
+}
+
+int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
+{
+ int r;
+
+ down_read(&cmd->root_lock);
+ r = cmd->changed;
+ up_read(&cmd->root_lock);
+
+ return r;
+}
+
+static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
+{
+ int r;
+ unsigned flags;
+ dm_oblock_t oblock;
+ __le64 value;
+
+ r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
+ if (r)
+ return r;
+
+ unpack_value(value, &oblock, &flags);
+
+ if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
+ /* nothing to be done */
+ return 0;
+
+ value = pack_value(oblock, flags | (dirty ? M_DIRTY : 0));
+ __dm_bless_for_disk(&value);
+
+ r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
+ &value, &cmd->root);
+ if (r)
+ return r;
+
+ cmd->changed = true;
+ return 0;
+
+}
+
+int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
+ dm_cblock_t cblock, bool dirty)
+{
+ int r;
+
+ down_write(&cmd->root_lock);
+ r = __dirty(cmd, cblock, dirty);
+ up_write(&cmd->root_lock);
+
+ return r;
+}
+
+void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
+ struct dm_cache_statistics *stats)
+{
+ down_read(&cmd->root_lock);
+ memcpy(stats, &cmd->stats, sizeof(*stats));
+ up_read(&cmd->root_lock);
+}
+
+void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
+ struct dm_cache_statistics *stats)
+{
+ down_write(&cmd->root_lock);
+ memcpy(&cmd->stats, stats, sizeof(*stats));
+ up_write(&cmd->root_lock);
+}
+
+int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
+{
+ int r;
+ flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
+ clear_clean_shutdown);
+
+ down_write(&cmd->root_lock);
+ r = __commit_transaction(cmd, mutator);
+ if (r)
+ goto out;
+
+ r = __begin_transaction(cmd);
+
+out:
+ up_write(&cmd->root_lock);
+ return r;
+}
+
+int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
+ dm_block_t *result)
+{
+ int r = -EINVAL;
+
+ down_read(&cmd->root_lock);
+ r = dm_sm_get_nr_free(cmd->metadata_sm, result);
+ up_read(&cmd->root_lock);
+
+ return r;
+}
+
+int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
+ dm_block_t *result)
+{
+ int r = -EINVAL;
+
+ down_read(&cmd->root_lock);
+ r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
+ up_read(&cmd->root_lock);
+
+ return r;
+}
+
+/*----------------------------------------------------------------*/
+
+static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
+{
+ int r;
+ __le32 value;
+ size_t hint_size;
+ const char *policy_name = dm_cache_policy_get_name(policy);
+
+ if (!policy_name[0] ||
+ (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
+ return -EINVAL;
+
+ if (strcmp(cmd->policy_name, policy_name)) {
+ strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
+
+ hint_size = dm_cache_policy_get_hint_size(policy);
+ if (!hint_size)
+ return 0; /* short-circuit hints initialization */
+ cmd->policy_hint_size = hint_size;
+
+ if (cmd->hint_root) {
+ r = dm_array_del(&cmd->hint_info, cmd->hint_root);
+ if (r)
+ return r;
+ }
+
+ r = dm_array_empty(&cmd->hint_info, &cmd->hint_root);
+ if (r)
+ return r;
+
+ value = cpu_to_le32(0);
+ __dm_bless_for_disk(&value);
+ r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0,
+ from_cblock(cmd->cache_blocks),
+ &value, &cmd->hint_root);
+ if (r)
+ return r;
+ }
+
+ return 0;
+}
+
+int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
+{
+ int r;
+
+ down_write(&cmd->root_lock);
+ r = begin_hints(cmd, policy);
+ up_write(&cmd->root_lock);
+
+ return r;
+}
+
+static int save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock,
+ uint32_t hint)
+{
+ int r;
+ __le32 value = cpu_to_le32(hint);
+ __dm_bless_for_disk(&value);
+
+ r = dm_array_set_value(&cmd->hint_info, cmd->hint_root,
+ from_cblock(cblock), &value, &cmd->hint_root);
+ cmd->changed = true;
+
+ return r;
+}
+
+int dm_cache_save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock,
+ uint32_t hint)
+{
+ int r;
+
+ if (!hints_array_initialized(cmd))
+ return 0;
+
+ down_write(&cmd->root_lock);
+ r = save_hint(cmd, cblock, hint);
+ up_write(&cmd->root_lock);
+
+ return r;
+}
diff --git a/drivers/md/dm-cache-metadata.h b/drivers/md/dm-cache-metadata.h
new file mode 100644
index 0000000..135864e
--- /dev/null
+++ b/drivers/md/dm-cache-metadata.h
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef DM_CACHE_METADATA_H
+#define DM_CACHE_METADATA_H
+
+#include "dm-cache-block-types.h"
+#include "dm-cache-policy-internal.h"
+
+/*----------------------------------------------------------------*/
+
+#define DM_CACHE_METADATA_BLOCK_SIZE 4096
+
+/* FIXME: remove this restriction */
+/*
+ * The metadata device is currently limited in size.
+ *
+ * We have one block of index, which can hold 255 index entries. Each
+ * index entry contains allocation info about 16k metadata blocks.
+ */
+#define DM_CACHE_METADATA_MAX_SECTORS (255 * (1 << 14) * (DM_CACHE_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT)))
+
+/*
+ * A metadata device larger than 16GB triggers a warning.
+ */
+#define DM_CACHE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT))
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Ext[234]-style compat feature flags.
+ *
+ * A new feature which old metadata will still be compatible with should
+ * define a DM_CACHE_FEATURE_COMPAT_* flag (rarely useful).
+ *
+ * A new feature that is not compatible with old code should define a
+ * DM_CACHE_FEATURE_INCOMPAT_* flag and guard the relevant code with
+ * that flag.
+ *
+ * A new feature that is not compatible with old code accessing the
+ * metadata RDWR should define a DM_CACHE_FEATURE_RO_COMPAT_* flag and
+ * guard the relevant code with that flag.
+ *
+ * As these various flags are defined they should be added to the
+ * following masks.
+ */
+#define DM_CACHE_FEATURE_COMPAT_SUPP 0UL
+#define DM_CACHE_FEATURE_COMPAT_RO_SUPP 0UL
+#define DM_CACHE_FEATURE_INCOMPAT_SUPP 0UL
+
+/*
+ * Reopens or creates a new, empty metadata volume.
+ * Returns an ERR_PTR on failure.
+ */
+struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
+ sector_t data_block_size,
+ bool may_format_device,
+ size_t policy_hint_size);
+
+void dm_cache_metadata_close(struct dm_cache_metadata *cmd);
+
+/*
+ * The metadata needs to know how many cache blocks there are. We don't
+ * care about the origin, assuming the core target is giving us valid
+ * origin blocks to map to.
+ */
+int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size);
+dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd);
+
+int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
+ sector_t discard_block_size,
+ dm_dblock_t new_nr_entries);
+
+typedef int (*load_discard_fn)(void *context, sector_t discard_block_size,
+ dm_dblock_t dblock, bool discarded);
+int dm_cache_load_discards(struct dm_cache_metadata *cmd,
+ load_discard_fn fn, void *context);
+
+int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_dblock_t dblock, bool discard);
+
+int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock);
+int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock, dm_oblock_t oblock);
+int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd);
+
+typedef int (*load_mapping_fn)(void *context, dm_oblock_t oblock,
+ dm_cblock_t cblock, bool dirty,
+ uint32_t hint, bool hint_valid);
+int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
+ const char *policy_name,
+ load_mapping_fn fn,
+ void *context);
+
+int dm_cache_set_dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty);
+
+struct dm_cache_statistics {
+ uint32_t read_hits;
+ uint32_t read_misses;
+ uint32_t write_hits;
+ uint32_t write_misses;
+};
+
+void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
+ struct dm_cache_statistics *stats);
+void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
+ struct dm_cache_statistics *stats);
+
+int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown);
+
+int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
+ dm_block_t *result);
+
+int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
+ dm_block_t *result);
+
+void dm_cache_dump(struct dm_cache_metadata *cmd);
+
+/*
+ * The policy is invited to save a 32bit hint value for every cblock (eg,
+ * for a hit count). These are stored against the policy name. If
+ * policies are changed, then hints will be lost. If the machine crashes,
+ * hints will be lost.
+ *
+ * The hints are indexed by the cblock, but many policies will not
+ * neccessarily have a fast way of accessing efficiently via cblock. So
+ * rather than querying the policy for each cblock, we let it walk its data
+ * structures and fill in the hints in whatever order it wishes.
+ */
+
+int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *p);
+
+/*
+ * requests hints for every cblock and stores in the metadata device.
+ */
+int dm_cache_save_hint(struct dm_cache_metadata *cmd,
+ dm_cblock_t cblock, uint32_t hint);
+
+/*----------------------------------------------------------------*/
+
+#endif /* DM_CACHE_METADATA_H */
diff --git a/drivers/md/dm-cache-policy-cleaner.c b/drivers/md/dm-cache-policy-cleaner.c
new file mode 100644
index 0000000..cc05d70
--- /dev/null
+++ b/drivers/md/dm-cache-policy-cleaner.c
@@ -0,0 +1,464 @@
+/*
+ * Copyright (C) 2012 Red Hat. All rights reserved.
+ *
+ * writeback cache policy supporting flushing out dirty cache blocks.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-cache-policy.h"
+#include "dm.h"
+
+#include <linux/hash.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+/*----------------------------------------------------------------*/
+
+#define DM_MSG_PREFIX "cache cleaner"
+#define CLEANER_VERSION "1.0.0"
+
+/* Cache entry struct. */
+struct wb_cache_entry {
+ struct list_head list;
+ struct hlist_node hlist;
+
+ dm_oblock_t oblock;
+ dm_cblock_t cblock;
+ bool dirty:1;
+ bool pending:1;
+};
+
+struct hash {
+ struct hlist_head *table;
+ dm_block_t hash_bits;
+ unsigned nr_buckets;
+};
+
+struct policy {
+ struct dm_cache_policy policy;
+ spinlock_t lock;
+
+ struct list_head free;
+ struct list_head clean;
+ struct list_head clean_pending;
+ struct list_head dirty;
+
+ /*
+ * We know exactly how many cblocks will be needed,
+ * so we can allocate them up front.
+ */
+ dm_cblock_t cache_size, nr_cblocks_allocated;
+ struct wb_cache_entry *cblocks;
+ struct hash chash;
+};
+
+/*----------------------------------------------------------------------------*/
+
+/*
+ * Low-level functions.
+ */
+static unsigned next_power(unsigned n, unsigned min)
+{
+ return roundup_pow_of_two(max(n, min));
+}
+
+static struct policy *to_policy(struct dm_cache_policy *p)
+{
+ return container_of(p, struct policy, policy);
+}
+
+static struct list_head *list_pop(struct list_head *q)
+{
+ struct list_head *r = q->next;
+
+ list_del(r);
+
+ return r;
+}
+
+/*----------------------------------------------------------------------------*/
+
+/* Allocate/free various resources. */
+static int alloc_hash(struct hash *hash, unsigned elts)
+{
+ hash->nr_buckets = next_power(elts >> 4, 16);
+ hash->hash_bits = ffs(hash->nr_buckets) - 1;
+ hash->table = vzalloc(sizeof(*hash->table) * hash->nr_buckets);
+
+ return hash->table ? 0 : -ENOMEM;
+}
+
+static void free_hash(struct hash *hash)
+{
+ vfree(hash->table);
+}
+
+static int alloc_cache_blocks_with_hash(struct policy *p, dm_cblock_t cache_size)
+{
+ int r = -ENOMEM;
+
+ p->cblocks = vzalloc(sizeof(*p->cblocks) * from_cblock(cache_size));
+ if (p->cblocks) {
+ unsigned u = from_cblock(cache_size);
+
+ while (u--)
+ list_add(&p->cblocks[u].list, &p->free);
+
+ p->nr_cblocks_allocated = 0;
+
+ /* Cache entries hash. */
+ r = alloc_hash(&p->chash, from_cblock(cache_size));
+ if (r)
+ vfree(p->cblocks);
+ }
+
+ return r;
+}
+
+static void free_cache_blocks_and_hash(struct policy *p)
+{
+ free_hash(&p->chash);
+ vfree(p->cblocks);
+}
+
+static struct wb_cache_entry *alloc_cache_entry(struct policy *p)
+{
+ struct wb_cache_entry *e;
+
+ BUG_ON(from_cblock(p->nr_cblocks_allocated) >= from_cblock(p->cache_size));
+
+ e = list_entry(list_pop(&p->free), struct wb_cache_entry, list);
+ p->nr_cblocks_allocated = to_cblock(from_cblock(p->nr_cblocks_allocated) + 1);
+
+ return e;
+}
+
+/*----------------------------------------------------------------------------*/
+
+/* Hash functions (lookup, insert, remove). */
+static struct wb_cache_entry *lookup_cache_entry(struct policy *p, dm_oblock_t oblock)
+{
+ struct hash *hash = &p->chash;
+ unsigned h = hash_64(from_oblock(oblock), hash->hash_bits);
+ struct wb_cache_entry *cur;
+ struct hlist_head *bucket = &hash->table[h];
+
+ hlist_for_each_entry(cur, bucket, hlist) {
+ if (cur->oblock == oblock) {
+ /* Move upfront bucket for faster access. */
+ hlist_del(&cur->hlist);
+ hlist_add_head(&cur->hlist, bucket);
+ return cur;
+ }
+ }
+
+ return NULL;
+}
+
+static void insert_cache_hash_entry(struct policy *p, struct wb_cache_entry *e)
+{
+ unsigned h = hash_64(from_oblock(e->oblock), p->chash.hash_bits);
+
+ hlist_add_head(&e->hlist, &p->chash.table[h]);
+}
+
+static void remove_cache_hash_entry(struct wb_cache_entry *e)
+{
+ hlist_del(&e->hlist);
+}
+
+/* Public interface (see dm-cache-policy.h */
+static int wb_map(struct dm_cache_policy *pe, dm_oblock_t oblock,
+ bool can_block, bool can_migrate, bool discarded_oblock,
+ struct bio *bio, struct policy_result *result)
+{
+ struct policy *p = to_policy(pe);
+ struct wb_cache_entry *e;
+ unsigned long flags;
+
+ result->op = POLICY_MISS;
+
+ if (can_block)
+ spin_lock_irqsave(&p->lock, flags);
+
+ else if (!spin_trylock_irqsave(&p->lock, flags))
+ return -EWOULDBLOCK;
+
+ e = lookup_cache_entry(p, oblock);
+ if (e) {
+ result->op = POLICY_HIT;
+ result->cblock = e->cblock;
+
+ }
+
+ spin_unlock_irqrestore(&p->lock, flags);
+
+ return 0;
+}
+
+static int wb_lookup(struct dm_cache_policy *pe, dm_oblock_t oblock, dm_cblock_t *cblock)
+{
+ int r;
+ struct policy *p = to_policy(pe);
+ struct wb_cache_entry *e;
+ unsigned long flags;
+
+ if (!spin_trylock_irqsave(&p->lock, flags))
+ return -EWOULDBLOCK;
+
+ e = lookup_cache_entry(p, oblock);
+ if (e) {
+ *cblock = e->cblock;
+ r = 0;
+
+ } else
+ r = -ENOENT;
+
+ spin_unlock_irqrestore(&p->lock, flags);
+
+ return r;
+}
+
+static void __set_clear_dirty(struct dm_cache_policy *pe, dm_oblock_t oblock, bool set)
+{
+ struct policy *p = to_policy(pe);
+ struct wb_cache_entry *e;
+
+ e = lookup_cache_entry(p, oblock);
+ BUG_ON(!e);
+
+ if (set) {
+ if (!e->dirty) {
+ e->dirty = true;
+ list_move(&e->list, &p->dirty);
+ }
+
+ } else {
+ if (e->dirty) {
+ e->pending = false;
+ e->dirty = false;
+ list_move(&e->list, &p->clean);
+ }
+ }
+}
+
+static void wb_set_dirty(struct dm_cache_policy *pe, dm_oblock_t oblock)
+{
+ struct policy *p = to_policy(pe);
+ unsigned long flags;
+
+ spin_lock_irqsave(&p->lock, flags);
+ __set_clear_dirty(pe, oblock, true);
+ spin_unlock_irqrestore(&p->lock, flags);
+}
+
+static void wb_clear_dirty(struct dm_cache_policy *pe, dm_oblock_t oblock)
+{
+ struct policy *p = to_policy(pe);
+ unsigned long flags;
+
+ spin_lock_irqsave(&p->lock, flags);
+ __set_clear_dirty(pe, oblock, false);
+ spin_unlock_irqrestore(&p->lock, flags);
+}
+
+static void add_cache_entry(struct policy *p, struct wb_cache_entry *e)
+{
+ insert_cache_hash_entry(p, e);
+ if (e->dirty)
+ list_add(&e->list, &p->dirty);
+ else
+ list_add(&e->list, &p->clean);
+}
+
+static int wb_load_mapping(struct dm_cache_policy *pe,
+ dm_oblock_t oblock, dm_cblock_t cblock,
+ uint32_t hint, bool hint_valid)
+{
+ int r;
+ struct policy *p = to_policy(pe);
+ struct wb_cache_entry *e = alloc_cache_entry(p);
+
+ if (e) {
+ e->cblock = cblock;
+ e->oblock = oblock;
+ e->dirty = false; /* blocks default to clean */
+ add_cache_entry(p, e);
+ r = 0;
+
+ } else
+ r = -ENOMEM;
+
+ return r;
+}
+
+static void wb_destroy(struct dm_cache_policy *pe)
+{
+ struct policy *p = to_policy(pe);
+
+ free_cache_blocks_and_hash(p);
+ kfree(p);
+}
+
+static struct wb_cache_entry *__wb_force_remove_mapping(struct policy *p, dm_oblock_t oblock)
+{
+ struct wb_cache_entry *r = lookup_cache_entry(p, oblock);
+
+ BUG_ON(!r);
+
+ remove_cache_hash_entry(r);
+ list_del(&r->list);
+
+ return r;
+}
+
+static void wb_remove_mapping(struct dm_cache_policy *pe, dm_oblock_t oblock)
+{
+ struct policy *p = to_policy(pe);
+ struct wb_cache_entry *e;
+ unsigned long flags;
+
+ spin_lock_irqsave(&p->lock, flags);
+ e = __wb_force_remove_mapping(p, oblock);
+ list_add_tail(&e->list, &p->free);
+ BUG_ON(!from_cblock(p->nr_cblocks_allocated));
+ p->nr_cblocks_allocated = to_cblock(from_cblock(p->nr_cblocks_allocated) - 1);
+ spin_unlock_irqrestore(&p->lock, flags);
+}
+
+static void wb_force_mapping(struct dm_cache_policy *pe,
+ dm_oblock_t current_oblock, dm_oblock_t oblock)
+{
+ struct policy *p = to_policy(pe);
+ struct wb_cache_entry *e;
+ unsigned long flags;
+
+ spin_lock_irqsave(&p->lock, flags);
+ e = __wb_force_remove_mapping(p, current_oblock);
+ e->oblock = oblock;
+ add_cache_entry(p, e);
+ spin_unlock_irqrestore(&p->lock, flags);
+}
+
+static struct wb_cache_entry *get_next_dirty_entry(struct policy *p)
+{
+ struct list_head *l;
+ struct wb_cache_entry *r;
+
+ if (list_empty(&p->dirty))
+ return NULL;
+
+ l = list_pop(&p->dirty);
+ r = container_of(l, struct wb_cache_entry, list);
+ list_add(l, &p->clean_pending);
+
+ return r;
+}
+
+static int wb_writeback_work(struct dm_cache_policy *pe,
+ dm_oblock_t *oblock,
+ dm_cblock_t *cblock)
+{
+ int r = -ENOENT;
+ struct policy *p = to_policy(pe);
+ struct wb_cache_entry *e;
+ unsigned long flags;
+
+ spin_lock_irqsave(&p->lock, flags);
+
+ e = get_next_dirty_entry(p);
+ if (e) {
+ *oblock = e->oblock;
+ *cblock = e->cblock;
+ r = 0;
+ }
+
+ spin_unlock_irqrestore(&p->lock, flags);
+
+ return r;
+}
+
+static dm_cblock_t wb_residency(struct dm_cache_policy *pe)
+{
+ return to_policy(pe)->nr_cblocks_allocated;
+}
+
+/* Init the policy plugin interface function pointers. */
+static void init_policy_functions(struct policy *p)
+{
+ p->policy.destroy = wb_destroy;
+ p->policy.map = wb_map;
+ p->policy.lookup = wb_lookup;
+ p->policy.set_dirty = wb_set_dirty;
+ p->policy.clear_dirty = wb_clear_dirty;
+ p->policy.load_mapping = wb_load_mapping;
+ p->policy.walk_mappings = NULL;
+ p->policy.remove_mapping = wb_remove_mapping;
+ p->policy.writeback_work = wb_writeback_work;
+ p->policy.force_mapping = wb_force_mapping;
+ p->policy.residency = wb_residency;
+ p->policy.tick = NULL;
+}
+
+static struct dm_cache_policy *wb_create(dm_cblock_t cache_size,
+ sector_t origin_size,
+ sector_t cache_block_size)
+{
+ int r;
+ struct policy *p = kzalloc(sizeof(*p), GFP_KERNEL);
+
+ if (!p)
+ return NULL;
+
+ init_policy_functions(p);
+ INIT_LIST_HEAD(&p->free);
+ INIT_LIST_HEAD(&p->clean);
+ INIT_LIST_HEAD(&p->clean_pending);
+ INIT_LIST_HEAD(&p->dirty);
+
+ p->cache_size = cache_size;
+ spin_lock_init(&p->lock);
+
+ /* Allocate cache entry structs and add them to free list. */
+ r = alloc_cache_blocks_with_hash(p, cache_size);
+ if (!r)
+ return &p->policy;
+
+ kfree(p);
+
+ return NULL;
+}
+/*----------------------------------------------------------------------------*/
+
+static struct dm_cache_policy_type wb_policy_type = {
+ .name = "cleaner",
+ .hint_size = 0,
+ .owner = THIS_MODULE,
+ .create = wb_create
+};
+
+static int __init wb_init(void)
+{
+ int r = dm_cache_policy_register(&wb_policy_type);
+
+ if (r < 0)
+ DMERR("register failed %d", r);
+ else
+ DMINFO("version " CLEANER_VERSION " loaded");
+
+ return r;
+}
+
+static void __exit wb_exit(void)
+{
+ dm_cache_policy_unregister(&wb_policy_type);
+}
+
+module_init(wb_init);
+module_exit(wb_exit);
+
+MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@redhat.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("cleaner cache policy");
diff --git a/drivers/md/dm-cache-policy-internal.h b/drivers/md/dm-cache-policy-internal.h
new file mode 100644
index 0000000..52a75be
--- /dev/null
+++ b/drivers/md/dm-cache-policy-internal.h
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2012 Red Hat. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef DM_CACHE_POLICY_INTERNAL_H
+#define DM_CACHE_POLICY_INTERNAL_H
+
+#include "dm-cache-policy.h"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Little inline functions that simplify calling the policy methods.
+ */
+static inline int policy_map(struct dm_cache_policy *p, dm_oblock_t oblock,
+ bool can_block, bool can_migrate, bool discarded_oblock,
+ struct bio *bio, struct policy_result *result)
+{
+ return p->map(p, oblock, can_block, can_migrate, discarded_oblock, bio, result);
+}
+
+static inline int policy_lookup(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock)
+{
+ BUG_ON(!p->lookup);
+ return p->lookup(p, oblock, cblock);
+}
+
+static inline void policy_set_dirty(struct dm_cache_policy *p, dm_oblock_t oblock)
+{
+ if (p->set_dirty)
+ p->set_dirty(p, oblock);
+}
+
+static inline void policy_clear_dirty(struct dm_cache_policy *p, dm_oblock_t oblock)
+{
+ if (p->clear_dirty)
+ p->clear_dirty(p, oblock);
+}
+
+static inline int policy_load_mapping(struct dm_cache_policy *p,
+ dm_oblock_t oblock, dm_cblock_t cblock,
+ uint32_t hint, bool hint_valid)
+{
+ return p->load_mapping(p, oblock, cblock, hint, hint_valid);
+}
+
+static inline int policy_walk_mappings(struct dm_cache_policy *p,
+ policy_walk_fn fn, void *context)
+{
+ return p->walk_mappings ? p->walk_mappings(p, fn, context) : 0;
+}
+
+static inline int policy_writeback_work(struct dm_cache_policy *p,
+ dm_oblock_t *oblock,
+ dm_cblock_t *cblock)
+{
+ return p->writeback_work ? p->writeback_work(p, oblock, cblock) : -ENOENT;
+}
+
+static inline void policy_remove_mapping(struct dm_cache_policy *p, dm_oblock_t oblock)
+{
+ return p->remove_mapping(p, oblock);
+}
+
+static inline void policy_force_mapping(struct dm_cache_policy *p,
+ dm_oblock_t current_oblock, dm_oblock_t new_oblock)
+{
+ return p->force_mapping(p, current_oblock, new_oblock);
+}
+
+static inline dm_cblock_t policy_residency(struct dm_cache_policy *p)
+{
+ return p->residency(p);
+}
+
+static inline void policy_tick(struct dm_cache_policy *p)
+{
+ if (p->tick)
+ return p->tick(p);
+}
+
+static inline int policy_emit_config_values(struct dm_cache_policy *p, char *result, unsigned maxlen)
+{
+ ssize_t sz = 0;
+ if (p->emit_config_values)
+ return p->emit_config_values(p, result, maxlen);
+
+ DMEMIT("0");
+ return 0;
+}
+
+static inline int policy_set_config_value(struct dm_cache_policy *p,
+ const char *key, const char *value)
+{
+ return p->set_config_value ? p->set_config_value(p, key, value) : -EINVAL;
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Creates a new cache policy given a policy name, a cache size, an origin size and the block size.
+ */
+struct dm_cache_policy *dm_cache_policy_create(const char *name, dm_cblock_t cache_size,
+ sector_t origin_size, sector_t block_size);
+
+/*
+ * Destroys the policy. This drops references to the policy module as well
+ * as calling it's destroy method. So always use this rather than calling
+ * the policy->destroy method directly.
+ */
+void dm_cache_policy_destroy(struct dm_cache_policy *p);
+
+/*
+ * In case we've forgotten.
+ */
+const char *dm_cache_policy_get_name(struct dm_cache_policy *p);
+
+size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p);
+
+/*----------------------------------------------------------------*/
+
+#endif /* DM_CACHE_POLICY_INTERNAL_H */
diff --git a/drivers/md/dm-cache-policy-mq.c b/drivers/md/dm-cache-policy-mq.c
new file mode 100644
index 0000000..9641532
--- /dev/null
+++ b/drivers/md/dm-cache-policy-mq.c
@@ -0,0 +1,1195 @@
+/*
+ * Copyright (C) 2012 Red Hat. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-cache-policy.h"
+#include "dm.h"
+
+#include <linux/hash.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#define DM_MSG_PREFIX "cache-policy-mq"
+#define MQ_VERSION "1.0.0"
+
+static struct kmem_cache *mq_entry_cache;
+
+/*----------------------------------------------------------------*/
+
+static unsigned next_power(unsigned n, unsigned min)
+{
+ return roundup_pow_of_two(max(n, min));
+}
+
+/*----------------------------------------------------------------*/
+
+static unsigned long *alloc_bitset(unsigned nr_entries)
+{
+ size_t s = sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG);
+ return vzalloc(s);
+}
+
+static void free_bitset(unsigned long *bits)
+{
+ vfree(bits);
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Large, sequential ios are probably better left on the origin device since
+ * spindles tend to have good bandwidth.
+ *
+ * The io_tracker tries to spot when the io is in one of these sequential
+ * modes.
+ *
+ * Two thresholds to switch between random and sequential io mode are defaulting
+ * as follows and can be adjusted via the constructor and message interfaces.
+ */
+#define RANDOM_THRESHOLD_DEFAULT 4
+#define SEQUENTIAL_THRESHOLD_DEFAULT 512
+
+enum io_pattern {
+ PATTERN_SEQUENTIAL,
+ PATTERN_RANDOM
+};
+
+struct io_tracker {
+ enum io_pattern pattern;
+
+ unsigned nr_seq_samples;
+ unsigned nr_rand_samples;
+ unsigned thresholds[2];
+
+ dm_oblock_t last_end_oblock;
+};
+
+static void iot_init(struct io_tracker *t,
+ int sequential_threshold, int random_threshold)
+{
+ t->pattern = PATTERN_RANDOM;
+ t->nr_seq_samples = 0;
+ t->nr_rand_samples = 0;
+ t->last_end_oblock = 0;
+ t->thresholds[PATTERN_RANDOM] = random_threshold;
+ t->thresholds[PATTERN_SEQUENTIAL] = sequential_threshold;
+}
+
+static enum io_pattern iot_pattern(struct io_tracker *t)
+{
+ return t->pattern;
+}
+
+static void iot_update_stats(struct io_tracker *t, struct bio *bio)
+{
+ if (bio->bi_sector == from_oblock(t->last_end_oblock) + 1)
+ t->nr_seq_samples++;
+ else {
+ /*
+ * Just one non-sequential IO is enough to reset the
+ * counters.
+ */
+ if (t->nr_seq_samples) {
+ t->nr_seq_samples = 0;
+ t->nr_rand_samples = 0;
+ }
+
+ t->nr_rand_samples++;
+ }
+
+ t->last_end_oblock = to_oblock(bio->bi_sector + bio_sectors(bio) - 1);
+}
+
+static void iot_check_for_pattern_switch(struct io_tracker *t)
+{
+ switch (t->pattern) {
+ case PATTERN_SEQUENTIAL:
+ if (t->nr_rand_samples >= t->thresholds[PATTERN_RANDOM]) {
+ t->pattern = PATTERN_RANDOM;
+ t->nr_seq_samples = t->nr_rand_samples = 0;
+ }
+ break;
+
+ case PATTERN_RANDOM:
+ if (t->nr_seq_samples >= t->thresholds[PATTERN_SEQUENTIAL]) {
+ t->pattern = PATTERN_SEQUENTIAL;
+ t->nr_seq_samples = t->nr_rand_samples = 0;
+ }
+ break;
+ }
+}
+
+static void iot_examine_bio(struct io_tracker *t, struct bio *bio)
+{
+ iot_update_stats(t, bio);
+ iot_check_for_pattern_switch(t);
+}
+
+/*----------------------------------------------------------------*/
+
+
+/*
+ * This queue is divided up into different levels. Allowing us to push
+ * entries to the back of any of the levels. Think of it as a partially
+ * sorted queue.
+ */
+#define NR_QUEUE_LEVELS 16u
+
+struct queue {
+ struct list_head qs[NR_QUEUE_LEVELS];
+};
+
+static void queue_init(struct queue *q)
+{
+ unsigned i;
+
+ for (i = 0; i < NR_QUEUE_LEVELS; i++)
+ INIT_LIST_HEAD(q->qs + i);
+}
+
+/*
+ * Insert an entry to the back of the given level.
+ */
+static void queue_push(struct queue *q, unsigned level, struct list_head *elt)
+{
+ list_add_tail(elt, q->qs + level);
+}
+
+static void queue_remove(struct list_head *elt)
+{
+ list_del(elt);
+}
+
+/*
+ * Shifts all regions down one level. This has no effect on the order of
+ * the queue.
+ */
+static void queue_shift_down(struct queue *q)
+{
+ unsigned level;
+
+ for (level = 1; level < NR_QUEUE_LEVELS; level++)
+ list_splice_init(q->qs + level, q->qs + level - 1);
+}
+
+/*
+ * Gives us the oldest entry of the lowest popoulated level. If the first
+ * level is emptied then we shift down one level.
+ */
+static struct list_head *queue_pop(struct queue *q)
+{
+ unsigned level;
+ struct list_head *r;
+
+ for (level = 0; level < NR_QUEUE_LEVELS; level++)
+ if (!list_empty(q->qs + level)) {
+ r = q->qs[level].next;
+ list_del(r);
+
+ /* have we just emptied the bottom level? */
+ if (level == 0 && list_empty(q->qs))
+ queue_shift_down(q);
+
+ return r;
+ }
+
+ return NULL;
+}
+
+static struct list_head *list_pop(struct list_head *lh)
+{
+ struct list_head *r = lh->next;
+
+ BUG_ON(!r);
+ list_del_init(r);
+
+ return r;
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Describes a cache entry. Used in both the cache and the pre_cache.
+ */
+struct entry {
+ struct hlist_node hlist;
+ struct list_head list;
+ dm_oblock_t oblock;
+ dm_cblock_t cblock; /* valid iff in_cache */
+
+ /*
+ * FIXME: pack these better
+ */
+ bool in_cache:1;
+ unsigned hit_count;
+ unsigned generation;
+ unsigned tick;
+};
+
+struct mq_policy {
+ struct dm_cache_policy policy;
+
+ /* protects everything */
+ struct mutex lock;
+ dm_cblock_t cache_size;
+ struct io_tracker tracker;
+
+ /*
+ * We maintain two queues of entries. The cache proper contains
+ * the currently active mappings. Whereas the pre_cache tracks
+ * blocks that are being hit frequently and potential candidates
+ * for promotion to the cache.
+ */
+ struct queue pre_cache;
+ struct queue cache;
+
+ /*
+ * Keeps track of time, incremented by the core. We use this to
+ * avoid attributing multiple hits within the same tick.
+ *
+ * Access to tick_protected should be done with the spin lock held.
+ * It's copied to tick at the start of the map function (within the
+ * mutex).
+ */
+ spinlock_t tick_lock;
+ unsigned tick_protected;
+ unsigned tick;
+
+ /*
+ * A count of the number of times the map function has been called
+ * and found an entry in the pre_cache or cache. Currently used to
+ * calculate the generation.
+ */
+ unsigned hit_count;
+
+ /*
+ * A generation is a longish period that is used to trigger some
+ * book keeping effects. eg, decrementing hit counts on entries.
+ * This is needed to allow the cache to evolve as io patterns
+ * change.
+ */
+ unsigned generation;
+ unsigned generation_period; /* in lookups (will probably change) */
+
+ /*
+ * Entries in the pre_cache whose hit count passes the promotion
+ * threshold move to the cache proper. Working out the correct
+ * value for the promotion_threshold is crucial to this policy.
+ */
+ unsigned promote_threshold;
+
+ /*
+ * We need cache_size entries for the cache, and choose to have
+ * cache_size entries for the pre_cache too. One motivation for
+ * using the same size is to make the hit counts directly
+ * comparable between pre_cache and cache.
+ */
+ unsigned nr_entries;
+ unsigned nr_entries_allocated;
+ struct list_head free;
+
+ /*
+ * Cache blocks may be unallocated. We store this info in a
+ * bitset.
+ */
+ unsigned long *allocation_bitset;
+ unsigned nr_cblocks_allocated;
+ unsigned find_free_nr_words;
+ unsigned find_free_last_word;
+
+ /*
+ * The hash table allows us to quickly find an entry by origin
+ * block. Both pre_cache and cache entries are in here.
+ */
+ unsigned nr_buckets;
+ dm_block_t hash_bits;
+ struct hlist_head *table;
+};
+
+/*----------------------------------------------------------------*/
+/* Free/alloc mq cache entry structures. */
+static void takeout_queue(struct list_head *lh, struct queue *q)
+{
+ unsigned level;
+
+ for (level = 0; level < NR_QUEUE_LEVELS; level++)
+ list_splice(q->qs + level, lh);
+}
+
+static void free_entries(struct mq_policy *mq)
+{
+ struct entry *e, *tmp;
+
+ takeout_queue(&mq->free, &mq->pre_cache);
+ takeout_queue(&mq->free, &mq->cache);
+
+ list_for_each_entry_safe(e, tmp, &mq->free, list)
+ kmem_cache_free(mq_entry_cache, e);
+}
+
+static int alloc_entries(struct mq_policy *mq, unsigned elts)
+{
+ unsigned u = mq->nr_entries;
+
+ INIT_LIST_HEAD(&mq->free);
+ mq->nr_entries_allocated = 0;
+
+ while (u--) {
+ struct entry *e = kmem_cache_zalloc(mq_entry_cache, GFP_KERNEL);
+
+ if (!e) {
+ free_entries(mq);
+ return -ENOMEM;
+ }
+
+
+ list_add(&e->list, &mq->free);
+ }
+
+ return 0;
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Simple hash table implementation. Should replace with the standard hash
+ * table that's making its way upstream.
+ */
+static void hash_insert(struct mq_policy *mq, struct entry *e)
+{
+ unsigned h = hash_64(from_oblock(e->oblock), mq->hash_bits);
+
+ hlist_add_head(&e->hlist, mq->table + h);
+}
+
+static struct entry *hash_lookup(struct mq_policy *mq, dm_oblock_t oblock)
+{
+ unsigned h = hash_64(from_oblock(oblock), mq->hash_bits);
+ struct hlist_head *bucket = mq->table + h;
+ struct entry *e;
+
+ hlist_for_each_entry(e, bucket, hlist)
+ if (e->oblock == oblock) {
+ hlist_del(&e->hlist);
+ hlist_add_head(&e->hlist, bucket);
+ return e;
+ }
+
+ return NULL;
+}
+
+static void hash_remove(struct entry *e)
+{
+ hlist_del(&e->hlist);
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Allocates a new entry structure. The memory is allocated in one lump,
+ * so we just handing it out here. Returns NULL if all entries have
+ * already been allocated. Cannot fail otherwise.
+ */
+static struct entry *alloc_entry(struct mq_policy *mq)
+{
+ struct entry *e;
+
+ if (mq->nr_entries_allocated >= mq->nr_entries) {
+ BUG_ON(!list_empty(&mq->free));
+ return NULL;
+ }
+
+ e = list_entry(list_pop(&mq->free), struct entry, list);
+ INIT_LIST_HEAD(&e->list);
+ INIT_HLIST_NODE(&e->hlist);
+
+ mq->nr_entries_allocated++;
+ return e;
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Mark cache blocks allocated or not in the bitset.
+ */
+static void alloc_cblock(struct mq_policy *mq, dm_cblock_t cblock)
+{
+ BUG_ON(from_cblock(cblock) > from_cblock(mq->cache_size));
+ BUG_ON(test_bit(from_cblock(cblock), mq->allocation_bitset));
+
+ set_bit(from_cblock(cblock), mq->allocation_bitset);
+ mq->nr_cblocks_allocated++;
+}
+
+static void free_cblock(struct mq_policy *mq, dm_cblock_t cblock)
+{
+ BUG_ON(from_cblock(cblock) > from_cblock(mq->cache_size));
+ BUG_ON(!test_bit(from_cblock(cblock), mq->allocation_bitset));
+
+ clear_bit(from_cblock(cblock), mq->allocation_bitset);
+ mq->nr_cblocks_allocated--;
+}
+
+static bool any_free_cblocks(struct mq_policy *mq)
+{
+ return mq->nr_cblocks_allocated < from_cblock(mq->cache_size);
+}
+
+/*
+ * Fills result out with a cache block that isn't in use, or return
+ * -ENOSPC. This does _not_ mark the cblock as allocated, the caller is
+ * reponsible for that.
+ */
+static int __find_free_cblock(struct mq_policy *mq, unsigned begin, unsigned end,
+ dm_cblock_t *result, unsigned *last_word)
+{
+ int r = -ENOSPC;
+ unsigned w;
+
+ for (w = begin; w < end; w++) {
+ /*
+ * ffz is undefined if no zero exists
+ */
+ if (mq->allocation_bitset[w] != ~0UL) {
+ *last_word = w;
+ *result = to_cblock((w * BITS_PER_LONG) + ffz(mq->allocation_bitset[w]));
+ if (from_cblock(*result) < from_cblock(mq->cache_size))
+ r = 0;
+
+ break;
+ }
+ }
+
+ return r;
+}
+
+static int find_free_cblock(struct mq_policy *mq, dm_cblock_t *result)
+{
+ int r;
+
+ if (!any_free_cblocks(mq))
+ return -ENOSPC;
+
+ r = __find_free_cblock(mq, mq->find_free_last_word, mq->find_free_nr_words, result, &mq->find_free_last_word);
+ if (r == -ENOSPC && mq->find_free_last_word)
+ r = __find_free_cblock(mq, 0, mq->find_free_last_word, result, &mq->find_free_last_word);
+
+ return r;
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Now we get to the meat of the policy. This section deals with deciding
+ * when to to add entries to the pre_cache and cache, and move between
+ * them.
+ */
+
+/*
+ * The queue level is based on the log2 of the hit count.
+ */
+static unsigned queue_level(struct entry *e)
+{
+ return min((unsigned) ilog2(e->hit_count), NR_QUEUE_LEVELS - 1u);
+}
+
+/*
+ * Inserts the entry into the pre_cache or the cache. Ensures the cache
+ * block is marked as allocated if necc. Inserts into the hash table. Sets the
+ * tick which records when the entry was last moved about.
+ */
+static void push(struct mq_policy *mq, struct entry *e)
+{
+ e->tick = mq->tick;
+ hash_insert(mq, e);
+
+ if (e->in_cache) {
+ alloc_cblock(mq, e->cblock);
+ queue_push(&mq->cache, queue_level(e), &e->list);
+ } else
+ queue_push(&mq->pre_cache, queue_level(e), &e->list);
+}
+
+/*
+ * Removes an entry from pre_cache or cache. Removes from the hash table.
+ * Frees off the cache block if necc.
+ */
+static void del(struct mq_policy *mq, struct entry *e)
+{
+ queue_remove(&e->list);
+ hash_remove(e);
+ if (e->in_cache)
+ free_cblock(mq, e->cblock);
+}
+
+/*
+ * Like del, except it removes the first entry in the queue (ie. the least
+ * recently used).
+ */
+static struct entry *pop(struct mq_policy *mq, struct queue *q)
+{
+ struct entry *e = container_of(queue_pop(q), struct entry, list);
+
+ if (e) {
+ hash_remove(e);
+
+ if (e->in_cache)
+ free_cblock(mq, e->cblock);
+ }
+
+ return e;
+}
+
+/*
+ * Has this entry already been updated?
+ */
+static bool updated_this_tick(struct mq_policy *mq, struct entry *e)
+{
+ return mq->tick == e->tick;
+}
+
+/*
+ * The promotion threshold is adjusted every generation. As are the counts
+ * of the entries.
+ *
+ * At the moment the threshold is taken by averaging the hit counts of some
+ * of the entries in the cache (the first 20 entries of the first level).
+ *
+ * We can be much cleverer than this though. For example, each promotion
+ * could bump up the threshold helping to prevent churn. Much more to do
+ * here.
+ */
+
+#define MAX_TO_AVERAGE 20
+
+static void check_generation(struct mq_policy *mq)
+{
+ unsigned total = 0, nr = 0, count = 0, level;
+ struct list_head *head;
+ struct entry *e;
+
+ if ((mq->hit_count >= mq->generation_period) &&
+ (mq->nr_cblocks_allocated == from_cblock(mq->cache_size))) {
+
+ mq->hit_count = 0;
+ mq->generation++;
+
+ for (level = 0; level < NR_QUEUE_LEVELS && count < MAX_TO_AVERAGE; level++) {
+ head = mq->cache.qs + level;
+ list_for_each_entry(e, head, list) {
+ nr++;
+ total += e->hit_count;
+
+ if (++count >= MAX_TO_AVERAGE)
+ break;
+ }
+ }
+
+ mq->promote_threshold = nr ? total / nr : 1;
+ if (mq->promote_threshold * nr < total)
+ mq->promote_threshold++;
+ }
+}
+
+/*
+ * Whenever we use an entry we bump up it's hit counter, and push it to the
+ * back to it's current level.
+ */
+static void requeue_and_update_tick(struct mq_policy *mq, struct entry *e)
+{
+ if (updated_this_tick(mq, e))
+ return;
+
+ e->hit_count++;
+ mq->hit_count++;
+ check_generation(mq);
+
+ /* generation adjustment, to stop the counts increasing forever. */
+ /* FIXME: divide? */
+ /* e->hit_count -= min(e->hit_count - 1, mq->generation - e->generation); */
+ e->generation = mq->generation;
+
+ del(mq, e);
+ push(mq, e);
+}
+
+/*
+ * Demote the least recently used entry from the cache to the pre_cache.
+ * Returns the new cache entry to use, and the old origin block it was
+ * mapped to.
+ *
+ * We drop the hit count on the demoted entry back to 1 to stop it bouncing
+ * straight back into the cache if it's subsequently hit. There are
+ * various options here, and more experimentation would be good:
+ *
+ * - just forget about the demoted entry completely (ie. don't insert it
+ into the pre_cache).
+ * - divide the hit count rather that setting to some hard coded value.
+ * - set the hit count to a hard coded value other than 1, eg, is it better
+ * if it goes in at level 2?
+ */
+static dm_cblock_t demote_cblock(struct mq_policy *mq, dm_oblock_t *oblock)
+{
+ dm_cblock_t result;
+ struct entry *demoted = pop(mq, &mq->cache);
+
+ BUG_ON(!demoted);
+ result = demoted->cblock;
+ *oblock = demoted->oblock;
+ demoted->in_cache = false;
+ demoted->hit_count = 1;
+ push(mq, demoted);
+
+ return result;
+}
+
+/*
+ * We modify the basic promotion_threshold depending on the specific io.
+ *
+ * If the origin block has been discarded then there's no cost to copy it
+ * to the cache.
+ *
+ * We bias towards reads, since they can be demoted at no cost if they
+ * haven't been dirtied.
+ */
+#define DISCARDED_PROMOTE_THRESHOLD 1
+#define READ_PROMOTE_THRESHOLD 4
+#define WRITE_PROMOTE_THRESHOLD 8
+
+static unsigned adjusted_promote_threshold(struct mq_policy *mq,
+ bool discarded_oblock, int data_dir)
+{
+ if (discarded_oblock && any_free_cblocks(mq) && data_dir == WRITE)
+ /*
+ * We don't need to do any copying at all, so give this a
+ * very low threshold. In practice this only triggers
+ * during initial population after a format.
+ */
+ return DISCARDED_PROMOTE_THRESHOLD;
+
+ return data_dir == READ ?
+ (mq->promote_threshold + READ_PROMOTE_THRESHOLD) :
+ (mq->promote_threshold + WRITE_PROMOTE_THRESHOLD);
+}
+
+static bool should_promote(struct mq_policy *mq, struct entry *e,
+ bool discarded_oblock, int data_dir)
+{
+ return e->hit_count >=
+ adjusted_promote_threshold(mq, discarded_oblock, data_dir);
+}
+
+static int cache_entry_found(struct mq_policy *mq,
+ struct entry *e,
+ struct policy_result *result)
+{
+ requeue_and_update_tick(mq, e);
+
+ if (e->in_cache) {
+ result->op = POLICY_HIT;
+ result->cblock = e->cblock;
+ }
+
+ return 0;
+}
+
+/*
+ * Moves and entry from the pre_cache to the cache. The main work is
+ * finding which cache block to use.
+ */
+static int pre_cache_to_cache(struct mq_policy *mq, struct entry *e,
+ struct policy_result *result)
+{
+ dm_cblock_t cblock;
+
+ if (find_free_cblock(mq, &cblock) == -ENOSPC) {
+ result->op = POLICY_REPLACE;
+ cblock = demote_cblock(mq, &result->old_oblock);
+ } else
+ result->op = POLICY_NEW;
+
+ result->cblock = e->cblock = cblock;
+
+ del(mq, e);
+ e->in_cache = true;
+ push(mq, e);
+
+ return 0;
+}
+
+static int pre_cache_entry_found(struct mq_policy *mq, struct entry *e,
+ bool can_migrate, bool discarded_oblock,
+ int data_dir, struct policy_result *result)
+{
+ int r = 0;
+ bool updated = updated_this_tick(mq, e);
+
+ requeue_and_update_tick(mq, e);
+
+ if ((!discarded_oblock && updated) ||
+ !should_promote(mq, e, discarded_oblock, data_dir))
+ result->op = POLICY_MISS;
+ else if (!can_migrate)
+ r = -EWOULDBLOCK;
+ else
+ r = pre_cache_to_cache(mq, e, result);
+
+ return r;
+}
+
+static void insert_in_pre_cache(struct mq_policy *mq,
+ dm_oblock_t oblock)
+{
+ struct entry *e = alloc_entry(mq);
+
+ if (!e)
+ /*
+ * There's no spare entry structure, so we grab the least
+ * used one from the pre_cache.
+ */
+ e = pop(mq, &mq->pre_cache);
+
+ if (unlikely(!e)) {
+ DMWARN("couldn't pop from pre cache");
+ return;
+ }
+
+ e->in_cache = false;
+ e->oblock = oblock;
+ e->hit_count = 1;
+ e->generation = mq->generation;
+ push(mq, e);
+}
+
+static void insert_in_cache(struct mq_policy *mq, dm_oblock_t oblock,
+ struct policy_result *result)
+{
+ struct entry *e;
+ dm_cblock_t cblock;
+
+ if (find_free_cblock(mq, &cblock) == -ENOSPC) {
+ result->op = POLICY_MISS;
+ insert_in_pre_cache(mq, oblock);
+ return;
+ }
+
+ e = alloc_entry(mq);
+ if (unlikely(!e)) {
+ result->op = POLICY_MISS;
+ return;
+ }
+
+ e->oblock = oblock;
+ e->cblock = cblock;
+ e->in_cache = true;
+ e->hit_count = 1;
+ e->generation = mq->generation;
+ push(mq, e);
+
+ result->op = POLICY_NEW;
+ result->cblock = e->cblock;
+}
+
+static int no_entry_found(struct mq_policy *mq, dm_oblock_t oblock,
+ bool can_migrate, bool discarded_oblock,
+ int data_dir, struct policy_result *result)
+{
+ if (adjusted_promote_threshold(mq, discarded_oblock, data_dir) == 1) {
+ if (can_migrate)
+ insert_in_cache(mq, oblock, result);
+ else
+ return -EWOULDBLOCK;
+ } else {
+ insert_in_pre_cache(mq, oblock);
+ result->op = POLICY_MISS;
+ }
+
+ return 0;
+}
+
+/*
+ * Looks the oblock up in the hash table, then decides whether to put in
+ * pre_cache, or cache etc.
+ */
+static int map(struct mq_policy *mq, dm_oblock_t oblock,
+ bool can_migrate, bool discarded_oblock,
+ int data_dir, struct policy_result *result)
+{
+ int r = 0;
+ struct entry *e = hash_lookup(mq, oblock);
+
+ if (e && e->in_cache)
+ r = cache_entry_found(mq, e, result);
+ else if (iot_pattern(&mq->tracker) == PATTERN_SEQUENTIAL)
+ result->op = POLICY_MISS;
+ else if (e)
+ r = pre_cache_entry_found(mq, e, can_migrate, discarded_oblock,
+ data_dir, result);
+ else
+ r = no_entry_found(mq, oblock, can_migrate, discarded_oblock,
+ data_dir, result);
+
+ if (r == -EWOULDBLOCK)
+ result->op = POLICY_MISS;
+
+ return r;
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Public interface, via the policy struct. See dm-cache-policy.h for a
+ * description of these.
+ */
+
+static struct mq_policy *to_mq_policy(struct dm_cache_policy *p)
+{
+ return container_of(p, struct mq_policy, policy);
+}
+
+static void mq_destroy(struct dm_cache_policy *p)
+{
+ struct mq_policy *mq = to_mq_policy(p);
+
+ free_bitset(mq->allocation_bitset);
+ kfree(mq->table);
+ free_entries(mq);
+ kfree(mq);
+}
+
+static void copy_tick(struct mq_policy *mq)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&mq->tick_lock, flags);
+ mq->tick = mq->tick_protected;
+ spin_unlock_irqrestore(&mq->tick_lock, flags);
+}
+
+static int mq_map(struct dm_cache_policy *p, dm_oblock_t oblock,
+ bool can_block, bool can_migrate, bool discarded_oblock,
+ struct bio *bio, struct policy_result *result)
+{
+ int r;
+ struct mq_policy *mq = to_mq_policy(p);
+
+ result->op = POLICY_MISS;
+
+ if (can_block)
+ mutex_lock(&mq->lock);
+ else if (!mutex_trylock(&mq->lock))
+ return -EWOULDBLOCK;
+
+ copy_tick(mq);
+
+ iot_examine_bio(&mq->tracker, bio);
+ r = map(mq, oblock, can_migrate, discarded_oblock,
+ bio_data_dir(bio), result);
+
+ mutex_unlock(&mq->lock);
+
+ return r;
+}
+
+static int mq_lookup(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock)
+{
+ int r;
+ struct mq_policy *mq = to_mq_policy(p);
+ struct entry *e;
+
+ if (!mutex_trylock(&mq->lock))
+ return -EWOULDBLOCK;
+
+ e = hash_lookup(mq, oblock);
+ if (e && e->in_cache) {
+ *cblock = e->cblock;
+ r = 0;
+ } else
+ r = -ENOENT;
+
+ mutex_unlock(&mq->lock);
+
+ return r;
+}
+
+static int mq_load_mapping(struct dm_cache_policy *p,
+ dm_oblock_t oblock, dm_cblock_t cblock,
+ uint32_t hint, bool hint_valid)
+{
+ struct mq_policy *mq = to_mq_policy(p);
+ struct entry *e;
+
+ e = alloc_entry(mq);
+ if (!e)
+ return -ENOMEM;
+
+ e->cblock = cblock;
+ e->oblock = oblock;
+ e->in_cache = true;
+ e->hit_count = hint_valid ? hint : 1;
+ e->generation = mq->generation;
+ push(mq, e);
+
+ return 0;
+}
+
+static int mq_walk_mappings(struct dm_cache_policy *p, policy_walk_fn fn,
+ void *context)
+{
+ struct mq_policy *mq = to_mq_policy(p);
+ int r = 0;
+ struct entry *e;
+ unsigned level;
+
+ mutex_lock(&mq->lock);
+
+ for (level = 0; level < NR_QUEUE_LEVELS; level++)
+ list_for_each_entry(e, &mq->cache.qs[level], list) {
+ r = fn(context, e->cblock, e->oblock, e->hit_count);
+ if (r)
+ goto out;
+ }
+
+out:
+ mutex_unlock(&mq->lock);
+
+ return r;
+}
+
+static void remove_mapping(struct mq_policy *mq, dm_oblock_t oblock)
+{
+ struct entry *e = hash_lookup(mq, oblock);
+
+ BUG_ON(!e || !e->in_cache);
+
+ del(mq, e);
+ e->in_cache = false;
+ push(mq, e);
+}
+
+static void mq_remove_mapping(struct dm_cache_policy *p, dm_oblock_t oblock)
+{
+ struct mq_policy *mq = to_mq_policy(p);
+
+ mutex_lock(&mq->lock);
+ remove_mapping(mq, oblock);
+ mutex_unlock(&mq->lock);
+}
+
+static void force_mapping(struct mq_policy *mq,
+ dm_oblock_t current_oblock, dm_oblock_t new_oblock)
+{
+ struct entry *e = hash_lookup(mq, current_oblock);
+
+ BUG_ON(!e || !e->in_cache);
+
+ del(mq, e);
+ e->oblock = new_oblock;
+ push(mq, e);
+}
+
+static void mq_force_mapping(struct dm_cache_policy *p,
+ dm_oblock_t current_oblock, dm_oblock_t new_oblock)
+{
+ struct mq_policy *mq = to_mq_policy(p);
+
+ mutex_lock(&mq->lock);
+ force_mapping(mq, current_oblock, new_oblock);
+ mutex_unlock(&mq->lock);
+}
+
+static dm_cblock_t mq_residency(struct dm_cache_policy *p)
+{
+ struct mq_policy *mq = to_mq_policy(p);
+
+ /* FIXME: lock mutex, not sure we can block here */
+ return to_cblock(mq->nr_cblocks_allocated);
+}
+
+static void mq_tick(struct dm_cache_policy *p)
+{
+ struct mq_policy *mq = to_mq_policy(p);
+ unsigned long flags;
+
+ spin_lock_irqsave(&mq->tick_lock, flags);
+ mq->tick_protected++;
+ spin_unlock_irqrestore(&mq->tick_lock, flags);
+}
+
+static int mq_set_config_value(struct dm_cache_policy *p,
+ const char *key, const char *value)
+{
+ struct mq_policy *mq = to_mq_policy(p);
+ enum io_pattern pattern;
+ unsigned long tmp;
+
+ if (!strcasecmp(key, "random_threshold"))
+ pattern = PATTERN_RANDOM;
+ else if (!strcasecmp(key, "sequential_threshold"))
+ pattern = PATTERN_SEQUENTIAL;
+ else
+ return -EINVAL;
+
+ if (kstrtoul(value, 10, &tmp))
+ return -EINVAL;
+
+ mq->tracker.thresholds[pattern] = tmp;
+
+ return 0;
+}
+
+static int mq_emit_config_values(struct dm_cache_policy *p, char *result, unsigned maxlen)
+{
+ ssize_t sz = 0;
+ struct mq_policy *mq = to_mq_policy(p);
+
+ DMEMIT("4 random_threshold %u sequential_threshold %u",
+ mq->tracker.thresholds[PATTERN_RANDOM],
+ mq->tracker.thresholds[PATTERN_SEQUENTIAL]);
+
+ return 0;
+}
+
+/* Init the policy plugin interface function pointers. */
+static void init_policy_functions(struct mq_policy *mq)
+{
+ mq->policy.destroy = mq_destroy;
+ mq->policy.map = mq_map;
+ mq->policy.lookup = mq_lookup;
+ mq->policy.load_mapping = mq_load_mapping;
+ mq->policy.walk_mappings = mq_walk_mappings;
+ mq->policy.remove_mapping = mq_remove_mapping;
+ mq->policy.writeback_work = NULL;
+ mq->policy.force_mapping = mq_force_mapping;
+ mq->policy.residency = mq_residency;
+ mq->policy.tick = mq_tick;
+ mq->policy.emit_config_values = mq_emit_config_values;
+ mq->policy.set_config_value = mq_set_config_value;
+}
+
+static struct dm_cache_policy *mq_create(dm_cblock_t cache_size,
+ sector_t origin_size,
+ sector_t cache_block_size)
+{
+ int r;
+ struct mq_policy *mq = kzalloc(sizeof(*mq), GFP_KERNEL);
+
+ if (!mq)
+ return NULL;
+
+ init_policy_functions(mq);
+ iot_init(&mq->tracker, SEQUENTIAL_THRESHOLD_DEFAULT, RANDOM_THRESHOLD_DEFAULT);
+
+ mq->cache_size = cache_size;
+ mq->tick_protected = 0;
+ mq->tick = 0;
+ mq->hit_count = 0;
+ mq->generation = 0;
+ mq->promote_threshold = 0;
+ mutex_init(&mq->lock);
+ spin_lock_init(&mq->tick_lock);
+ mq->find_free_nr_words = dm_div_up(from_cblock(mq->cache_size), BITS_PER_LONG);
+ mq->find_free_last_word = 0;
+
+ queue_init(&mq->pre_cache);
+ queue_init(&mq->cache);
+ mq->generation_period = max((unsigned) from_cblock(cache_size), 1024U);
+
+ mq->nr_entries = 2 * from_cblock(cache_size);
+ r = alloc_entries(mq, mq->nr_entries);
+ if (r)
+ goto bad_cache_alloc;
+
+ mq->nr_entries_allocated = 0;
+ mq->nr_cblocks_allocated = 0;
+
+ mq->nr_buckets = next_power(from_cblock(cache_size) / 2, 16);
+ mq->hash_bits = ffs(mq->nr_buckets) - 1;
+ mq->table = kzalloc(sizeof(*mq->table) * mq->nr_buckets, GFP_KERNEL);
+ if (!mq->table)
+ goto bad_alloc_table;
+
+ mq->allocation_bitset = alloc_bitset(from_cblock(cache_size));
+ if (!mq->allocation_bitset)
+ goto bad_alloc_bitset;
+
+ return &mq->policy;
+
+bad_alloc_bitset:
+ kfree(mq->table);
+bad_alloc_table:
+ free_entries(mq);
+bad_cache_alloc:
+ kfree(mq);
+
+ return NULL;
+}
+
+/*----------------------------------------------------------------*/
+
+static struct dm_cache_policy_type mq_policy_type = {
+ .name = "mq",
+ .hint_size = 4,
+ .owner = THIS_MODULE,
+ .create = mq_create
+};
+
+static struct dm_cache_policy_type default_policy_type = {
+ .name = "default",
+ .hint_size = 4,
+ .owner = THIS_MODULE,
+ .create = mq_create
+};
+
+static int __init mq_init(void)
+{
+ int r;
+
+ mq_entry_cache = kmem_cache_create("dm_mq_policy_cache_entry",
+ sizeof(struct entry),
+ __alignof__(struct entry),
+ 0, NULL);
+ if (!mq_entry_cache)
+ goto bad;
+
+ r = dm_cache_policy_register(&mq_policy_type);
+ if (r) {
+ DMERR("register failed %d", r);
+ goto bad_register_mq;
+ }
+
+ r = dm_cache_policy_register(&default_policy_type);
+ if (!r) {
+ DMINFO("version " MQ_VERSION " loaded");
+ return 0;
+ }
+
+ DMERR("register failed (as default) %d", r);
+
+ dm_cache_policy_unregister(&mq_policy_type);
+bad_register_mq:
+ kmem_cache_destroy(mq_entry_cache);
+bad:
+ return -ENOMEM;
+}
+
+static void __exit mq_exit(void)
+{
+ dm_cache_policy_unregister(&mq_policy_type);
+ dm_cache_policy_unregister(&default_policy_type);
+
+ kmem_cache_destroy(mq_entry_cache);
+}
+
+module_init(mq_init);
+module_exit(mq_exit);
+
+MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("mq cache policy");
+
+MODULE_ALIAS("dm-cache-default");
diff --git a/drivers/md/dm-cache-policy.c b/drivers/md/dm-cache-policy.c
new file mode 100644
index 0000000..2cbf5fd
--- /dev/null
+++ b/drivers/md/dm-cache-policy.c
@@ -0,0 +1,161 @@
+/*
+ * Copyright (C) 2012 Red Hat. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-cache-policy-internal.h"
+#include "dm.h"
+
+#include <linux/module.h>
+#include <linux/slab.h>
+
+/*----------------------------------------------------------------*/
+
+#define DM_MSG_PREFIX "cache-policy"
+
+static DEFINE_SPINLOCK(register_lock);
+static LIST_HEAD(register_list);
+
+static struct dm_cache_policy_type *__find_policy(const char *name)
+{
+ struct dm_cache_policy_type *t;
+
+ list_for_each_entry(t, &register_list, list)
+ if (!strcmp(t->name, name))
+ return t;
+
+ return NULL;
+}
+
+static struct dm_cache_policy_type *__get_policy_once(const char *name)
+{
+ struct dm_cache_policy_type *t = __find_policy(name);
+
+ if (t && !try_module_get(t->owner)) {
+ DMWARN("couldn't get module %s", name);
+ t = ERR_PTR(-EINVAL);
+ }
+
+ return t;
+}
+
+static struct dm_cache_policy_type *get_policy_once(const char *name)
+{
+ struct dm_cache_policy_type *t;
+
+ spin_lock(&register_lock);
+ t = __get_policy_once(name);
+ spin_unlock(&register_lock);
+
+ return t;
+}
+
+static struct dm_cache_policy_type *get_policy(const char *name)
+{
+ struct dm_cache_policy_type *t;
+
+ t = get_policy_once(name);
+ if (IS_ERR(t))
+ return NULL;
+
+ if (t)
+ return t;
+
+ request_module("dm-cache-%s", name);
+
+ t = get_policy_once(name);
+ if (IS_ERR(t))
+ return NULL;
+
+ return t;
+}
+
+static void put_policy(struct dm_cache_policy_type *t)
+{
+ module_put(t->owner);
+}
+
+int dm_cache_policy_register(struct dm_cache_policy_type *type)
+{
+ int r;
+
+ /* One size fits all for now */
+ if (type->hint_size != 0 && type->hint_size != 4) {
+ DMWARN("hint size must be 0 or 4 but %llu supplied.", (unsigned long long) type->hint_size);
+ return -EINVAL;
+ }
+
+ spin_lock(&register_lock);
+ if (__find_policy(type->name)) {
+ DMWARN("attempt to register policy under duplicate name %s", type->name);
+ r = -EINVAL;
+ } else {
+ list_add(&type->list, &register_list);
+ r = 0;
+ }
+ spin_unlock(&register_lock);
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_cache_policy_register);
+
+void dm_cache_policy_unregister(struct dm_cache_policy_type *type)
+{
+ spin_lock(&register_lock);
+ list_del_init(&type->list);
+ spin_unlock(&register_lock);
+}
+EXPORT_SYMBOL_GPL(dm_cache_policy_unregister);
+
+struct dm_cache_policy *dm_cache_policy_create(const char *name,
+ dm_cblock_t cache_size,
+ sector_t origin_size,
+ sector_t cache_block_size)
+{
+ struct dm_cache_policy *p = NULL;
+ struct dm_cache_policy_type *type;
+
+ type = get_policy(name);
+ if (!type) {
+ DMWARN("unknown policy type");
+ return NULL;
+ }
+
+ p = type->create(cache_size, origin_size, cache_block_size);
+ if (!p) {
+ put_policy(type);
+ return NULL;
+ }
+ p->private = type;
+
+ return p;
+}
+EXPORT_SYMBOL_GPL(dm_cache_policy_create);
+
+void dm_cache_policy_destroy(struct dm_cache_policy *p)
+{
+ struct dm_cache_policy_type *t = p->private;
+
+ p->destroy(p);
+ put_policy(t);
+}
+EXPORT_SYMBOL_GPL(dm_cache_policy_destroy);
+
+const char *dm_cache_policy_get_name(struct dm_cache_policy *p)
+{
+ struct dm_cache_policy_type *t = p->private;
+
+ return t->name;
+}
+EXPORT_SYMBOL_GPL(dm_cache_policy_get_name);
+
+size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p)
+{
+ struct dm_cache_policy_type *t = p->private;
+
+ return t->hint_size;
+}
+EXPORT_SYMBOL_GPL(dm_cache_policy_get_hint_size);
+
+/*----------------------------------------------------------------*/
diff --git a/drivers/md/dm-cache-policy.h b/drivers/md/dm-cache-policy.h
new file mode 100644
index 0000000..f0f51b2
--- /dev/null
+++ b/drivers/md/dm-cache-policy.h
@@ -0,0 +1,228 @@
+/*
+ * Copyright (C) 2012 Red Hat. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef DM_CACHE_POLICY_H
+#define DM_CACHE_POLICY_H
+
+#include "dm-cache-block-types.h"
+
+#include <linux/device-mapper.h>
+
+/*----------------------------------------------------------------*/
+
+/* FIXME: make it clear which methods are optional. Get debug policy to
+ * double check this at start.
+ */
+
+/*
+ * The cache policy makes the important decisions about which blocks get to
+ * live on the faster cache device.
+ *
+ * When the core target has to remap a bio it calls the 'map' method of the
+ * policy. This returns an instruction telling the core target what to do.
+ *
+ * POLICY_HIT:
+ * That block is in the cache. Remap to the cache and carry on.
+ *
+ * POLICY_MISS:
+ * This block is on the origin device. Remap and carry on.
+ *
+ * POLICY_NEW:
+ * This block is currently on the origin device, but the policy wants to
+ * move it. The core should:
+ *
+ * - hold any further io to this origin block
+ * - copy the origin to the given cache block
+ * - release all the held blocks
+ * - remap the original block to the cache
+ *
+ * POLICY_REPLACE:
+ * This block is currently on the origin device. The policy wants to
+ * move it to the cache, with the added complication that the destination
+ * cache block needs a writeback first. The core should:
+ *
+ * - hold any further io to this origin block
+ * - hold any further io to the origin block that's being written back
+ * - writeback
+ * - copy new block to cache
+ * - release held blocks
+ * - remap bio to cache and reissue.
+ *
+ * Should the core run into trouble while processing a POLICY_NEW or
+ * POLICY_REPLACE instruction it will roll back the policies mapping using
+ * remove_mapping() or force_mapping(). These methods must not fail. This
+ * approach avoids having transactional semantics in the policy (ie, the
+ * core informing the policy when a migration is complete), and hence makes
+ * it easier to write new policies.
+ *
+ * In general policy methods should never block, except in the case of the
+ * map function when can_migrate is set. So be careful to implement using
+ * bounded, preallocated memory.
+ */
+enum policy_operation {
+ POLICY_HIT,
+ POLICY_MISS,
+ POLICY_NEW,
+ POLICY_REPLACE
+};
+
+/*
+ * This is the instruction passed back to the core target.
+ */
+struct policy_result {
+ enum policy_operation op;
+ dm_oblock_t old_oblock; /* POLICY_REPLACE */
+ dm_cblock_t cblock; /* POLICY_HIT, POLICY_NEW, POLICY_REPLACE */
+};
+
+typedef int (*policy_walk_fn)(void *context, dm_cblock_t cblock,
+ dm_oblock_t oblock, uint32_t hint);
+
+/*
+ * The cache policy object. Just a bunch of methods. It is envisaged that
+ * this structure will be embedded in a bigger, policy specific structure
+ * (ie. use container_of()).
+ */
+struct dm_cache_policy {
+
+ /*
+ * FIXME: make it clear which methods are optional, and which may
+ * block.
+ */
+
+ /*
+ * Destroys this object.
+ */
+ void (*destroy)(struct dm_cache_policy *p);
+
+ /*
+ * See large comment above.
+ *
+ * oblock - the origin block we're interested in.
+ *
+ * can_block - indicates whether the current thread is allowed to
+ * block. -EWOULDBLOCK returned if it can't and would.
+ *
+ * can_migrate - gives permission for POLICY_NEW or POLICY_REPLACE
+ * instructions. If denied and the policy would have
+ * returned one of these instructions it should
+ * return -EWOULDBLOCK.
+ *
+ * discarded_oblock - indicates whether the whole origin block is
+ * in a discarded state (FIXME: better to tell the
+ * policy about this sooner, so it can recycle that
+ * cache block if it wants.)
+ * bio - the bio that triggered this call.
+ * result - gets filled in with the instruction.
+ *
+ * May only return 0, or -EWOULDBLOCK (if !can_migrate)
+ */
+ int (*map)(struct dm_cache_policy *p, dm_oblock_t oblock,
+ bool can_block, bool can_migrate, bool discarded_oblock,
+ struct bio *bio, struct policy_result *result);
+
+ /*
+ * Sometimes we want to see if a block is in the cache, without
+ * triggering any update of stats. (ie. it's not a real hit).
+ *
+ * Must not block.
+ *
+ * Returns 1 iff in cache, 0 iff not, < 0 on error (-EWOULDBLOCK
+ * would be typical).
+ */
+ int (*lookup)(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock);
+
+ /*
+ * oblock must be a mapped block. Must not block.
+ */
+ void (*set_dirty)(struct dm_cache_policy *p, dm_oblock_t oblock);
+ void (*clear_dirty)(struct dm_cache_policy *p, dm_oblock_t oblock);
+
+ /*
+ * Called when a cache target is first created. Used to load a
+ * mapping from the metadata device into the policy.
+ */
+ int (*load_mapping)(struct dm_cache_policy *p, dm_oblock_t oblock,
+ dm_cblock_t cblock, uint32_t hint, bool hint_valid);
+
+ int (*walk_mappings)(struct dm_cache_policy *p, policy_walk_fn fn,
+ void *context);
+
+ /*
+ * Override functions used on the error paths of the core target.
+ * They must succeed.
+ */
+ void (*remove_mapping)(struct dm_cache_policy *p, dm_oblock_t oblock);
+ void (*force_mapping)(struct dm_cache_policy *p, dm_oblock_t current_oblock,
+ dm_oblock_t new_oblock);
+
+ int (*writeback_work)(struct dm_cache_policy *p, dm_oblock_t *oblock, dm_cblock_t *cblock);
+
+
+ /*
+ * How full is the cache?
+ */
+ dm_cblock_t (*residency)(struct dm_cache_policy *p);
+
+ /*
+ * Because of where we sit in the block layer, we can be asked to
+ * map a lot of little bios that are all in the same block (no
+ * queue merging has occurred). To stop the policy being fooled by
+ * these the core target sends regular tick() calls to the policy.
+ * The policy should only count an entry as hit once per tick.
+ */
+ void (*tick)(struct dm_cache_policy *p);
+
+ /*
+ * Configuration.
+ */
+ int (*emit_config_values)(struct dm_cache_policy *p,
+ char *result, unsigned maxlen);
+ int (*set_config_value)(struct dm_cache_policy *p,
+ const char *key, const char *value);
+
+ /*
+ * Book keeping ptr for the policy register, not for general use.
+ */
+ void *private;
+};
+
+/*----------------------------------------------------------------*/
+
+/*
+ * We maintain a little register of the different policy types.
+ */
+#define CACHE_POLICY_NAME_SIZE 16
+
+struct dm_cache_policy_type {
+ /* For use by the register code only. */
+ struct list_head list;
+
+ /*
+ * Policy writers should fill in these fields. The name field is
+ * what gets passed on the target line to select your policy.
+ */
+ char name[CACHE_POLICY_NAME_SIZE];
+
+ /*
+ * Policies may store a hint for each each cache block.
+ * Currently the size of this hint must be 0 or 4 bytes but we
+ * expect to relax this in future.
+ */
+ size_t hint_size;
+
+ struct module *owner;
+ struct dm_cache_policy *(*create)(dm_cblock_t cache_size,
+ sector_t origin_size,
+ sector_t block_size);
+};
+
+int dm_cache_policy_register(struct dm_cache_policy_type *type);
+void dm_cache_policy_unregister(struct dm_cache_policy_type *type);
+
+/*----------------------------------------------------------------*/
+
+#endif /* DM_CACHE_POLICY_H */
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
new file mode 100644
index 0000000..0f4e84b
--- /dev/null
+++ b/drivers/md/dm-cache-target.c
@@ -0,0 +1,2584 @@
+/*
+ * Copyright (C) 2012 Red Hat. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+#include "dm-bio-prison.h"
+#include "dm-cache-metadata.h"
+
+#include <linux/dm-io.h>
+#include <linux/dm-kcopyd.h>
+#include <linux/init.h>
+#include <linux/mempool.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#define DM_MSG_PREFIX "cache"
+
+DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle,
+ "A percentage of time allocated for copying to and/or from cache");
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Glossary:
+ *
+ * oblock: index of an origin block
+ * cblock: index of a cache block
+ * promotion: movement of a block from origin to cache
+ * demotion: movement of a block from cache to origin
+ * migration: movement of a block between the origin and cache device,
+ * either direction
+ */
+
+/*----------------------------------------------------------------*/
+
+static size_t bitset_size_in_bytes(unsigned nr_entries)
+{
+ return sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG);
+}
+
+static unsigned long *alloc_bitset(unsigned nr_entries)
+{
+ size_t s = bitset_size_in_bytes(nr_entries);
+ return vzalloc(s);
+}
+
+static void clear_bitset(void *bitset, unsigned nr_entries)
+{
+ size_t s = bitset_size_in_bytes(nr_entries);
+ memset(bitset, 0, s);
+}
+
+static void free_bitset(unsigned long *bits)
+{
+ vfree(bits);
+}
+
+/*----------------------------------------------------------------*/
+
+#define PRISON_CELLS 1024
+#define MIGRATION_POOL_SIZE 128
+#define COMMIT_PERIOD HZ
+#define MIGRATION_COUNT_WINDOW 10
+
+/*
+ * The block size of the device holding cache data must be >= 32KB
+ */
+#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT)
+
+/*
+ * FIXME: the cache is read/write for the time being.
+ */
+enum cache_mode {
+ CM_WRITE, /* metadata may be changed */
+ CM_READ_ONLY, /* metadata may not be changed */
+};
+
+struct cache_features {
+ enum cache_mode mode;
+ bool write_through:1;
+};
+
+struct cache_stats {
+ atomic_t read_hit;
+ atomic_t read_miss;
+ atomic_t write_hit;
+ atomic_t write_miss;
+ atomic_t demotion;
+ atomic_t promotion;
+ atomic_t copies_avoided;
+ atomic_t cache_cell_clash;
+ atomic_t commit_count;
+ atomic_t discard_count;
+};
+
+struct cache {
+ struct dm_target *ti;
+ struct dm_target_callbacks callbacks;
+
+ /*
+ * Metadata is written to this device.
+ */
+ struct dm_dev *metadata_dev;
+
+ /*
+ * The slower of the two data devices. Typically a spindle.
+ */
+ struct dm_dev *origin_dev;
+
+ /*
+ * The faster of the two data devices. Typically an SSD.
+ */
+ struct dm_dev *cache_dev;
+
+ /*
+ * Cache features such as write-through.
+ */
+ struct cache_features features;
+
+ /*
+ * Size of the origin device in _complete_ blocks and native sectors.
+ */
+ dm_oblock_t origin_blocks;
+ sector_t origin_sectors;
+
+ /*
+ * Size of the cache device in blocks.
+ */
+ dm_cblock_t cache_size;
+
+ /*
+ * Fields for converting from sectors to blocks.
+ */
+ uint32_t sectors_per_block;
+ int sectors_per_block_shift;
+
+ struct dm_cache_metadata *cmd;
+
+ spinlock_t lock;
+ struct bio_list deferred_bios;
+ struct bio_list deferred_flush_bios;
+ struct list_head quiesced_migrations;
+ struct list_head completed_migrations;
+ struct list_head need_commit_migrations;
+ sector_t migration_threshold;
+ atomic_t nr_migrations;
+ wait_queue_head_t migration_wait;
+
+ /*
+ * cache_size entries, dirty if set
+ */
+ dm_cblock_t nr_dirty;
+ unsigned long *dirty_bitset;
+
+ /*
+ * origin_blocks entries, discarded if set.
+ */
+ sector_t discard_block_size; /* a power of 2 times sectors per block */
+ dm_dblock_t discard_nr_blocks;
+ unsigned long *discard_bitset;
+
+ struct dm_kcopyd_client *copier;
+ struct workqueue_struct *wq;
+ struct work_struct worker;
+
+ struct delayed_work waker;
+ unsigned long last_commit_jiffies;
+
+ struct dm_bio_prison *prison;
+ struct dm_deferred_set *all_io_ds;
+
+ mempool_t *migration_pool;
+ struct dm_cache_migration *next_migration;
+
+ struct dm_cache_policy *policy;
+ unsigned policy_nr_args;
+
+ bool need_tick_bio:1;
+ bool sized:1;
+ bool quiescing:1;
+ bool commit_requested:1;
+ bool loaded_mappings:1;
+ bool loaded_discards:1;
+
+ struct cache_stats stats;
+
+ /*
+ * Rather than reconstructing the table line for the status we just
+ * save it and regurgitate.
+ */
+ unsigned nr_ctr_args;
+ const char **ctr_args;
+};
+
+struct per_bio_data {
+ bool tick:1;
+ unsigned req_nr:2;
+ struct dm_deferred_entry *all_io_entry;
+};
+
+struct dm_cache_migration {
+ struct list_head list;
+ struct cache *cache;
+
+ unsigned long start_jiffies;
+ dm_oblock_t old_oblock;
+ dm_oblock_t new_oblock;
+ dm_cblock_t cblock;
+
+ bool err:1;
+ bool writeback:1;
+ bool demote:1;
+ bool promote:1;
+
+ struct dm_bio_prison_cell *old_ocell;
+ struct dm_bio_prison_cell *new_ocell;
+};
+
+/*
+ * Processing a bio in the worker thread may require these memory
+ * allocations. We prealloc to avoid deadlocks (the same worker thread
+ * frees them back to the mempool).
+ */
+struct prealloc {
+ struct dm_cache_migration *mg;
+ struct dm_bio_prison_cell *cell1;
+ struct dm_bio_prison_cell *cell2;
+};
+
+static void wake_worker(struct cache *cache)
+{
+ queue_work(cache->wq, &cache->worker);
+}
+
+/*----------------------------------------------------------------*/
+
+static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache)
+{
+ /* FIXME: change to use a local slab. */
+ return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT);
+}
+
+static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell)
+{
+ dm_bio_prison_free_cell(cache->prison, cell);
+}
+
+static int prealloc_data_structs(struct cache *cache, struct prealloc *p)
+{
+ if (!p->mg) {
+ p->mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT);
+ if (!p->mg)
+ return -ENOMEM;
+ }
+
+ if (!p->cell1) {
+ p->cell1 = alloc_prison_cell(cache);
+ if (!p->cell1)
+ return -ENOMEM;
+ }
+
+ if (!p->cell2) {
+ p->cell2 = alloc_prison_cell(cache);
+ if (!p->cell2)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void prealloc_free_structs(struct cache *cache, struct prealloc *p)
+{
+ if (p->cell2)
+ free_prison_cell(cache, p->cell2);
+
+ if (p->cell1)
+ free_prison_cell(cache, p->cell1);
+
+ if (p->mg)
+ mempool_free(p->mg, cache->migration_pool);
+}
+
+static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p)
+{
+ struct dm_cache_migration *mg = p->mg;
+
+ BUG_ON(!mg);
+ p->mg = NULL;
+
+ return mg;
+}
+
+/*
+ * You must have a cell within the prealloc struct to return. If not this
+ * function will BUG() rather than returning NULL.
+ */
+static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p)
+{
+ struct dm_bio_prison_cell *r = NULL;
+
+ if (p->cell1) {
+ r = p->cell1;
+ p->cell1 = NULL;
+
+ } else if (p->cell2) {
+ r = p->cell2;
+ p->cell2 = NULL;
+ } else
+ BUG();
+
+ return r;
+}
+
+/*
+ * You can't have more than two cells in a prealloc struct. BUG() will be
+ * called if you try and overfill.
+ */
+static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell)
+{
+ if (!p->cell2)
+ p->cell2 = cell;
+
+ else if (!p->cell1)
+ p->cell1 = cell;
+
+ else
+ BUG();
+}
+
+/*----------------------------------------------------------------*/
+
+static void build_key(dm_oblock_t oblock, struct dm_cell_key *key)
+{
+ key->virtual = 0;
+ key->dev = 0;
+ key->block = from_oblock(oblock);
+}
+
+/*
+ * The caller hands in a preallocated cell, and a free function for it.
+ * The cell will be freed if there's an error, or if it wasn't used because
+ * a cell with that key already exists.
+ */
+typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell);
+
+static int bio_detain(struct cache *cache, dm_oblock_t oblock,
+ struct bio *bio, struct dm_bio_prison_cell *cell_prealloc,
+ cell_free_fn free_fn, void *free_context,
+ struct dm_bio_prison_cell **cell_result)
+{
+ int r;
+ struct dm_cell_key key;
+
+ build_key(oblock, &key);
+ r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result);
+ if (r)
+ free_fn(free_context, cell_prealloc);
+
+ return r;
+}
+
+static int get_cell(struct cache *cache,
+ dm_oblock_t oblock,
+ struct prealloc *structs,
+ struct dm_bio_prison_cell **cell_result)
+{
+ int r;
+ struct dm_cell_key key;
+ struct dm_bio_prison_cell *cell_prealloc;
+
+ cell_prealloc = prealloc_get_cell(structs);
+
+ build_key(oblock, &key);
+ r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result);
+ if (r)
+ prealloc_put_cell(structs, cell_prealloc);
+
+ return r;
+}
+
+ /*----------------------------------------------------------------*/
+
+static bool is_dirty(struct cache *cache, dm_cblock_t b)
+{
+ return test_bit(from_cblock(b), cache->dirty_bitset);
+}
+
+static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock)
+{
+ if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) {
+ cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) + 1);
+ policy_set_dirty(cache->policy, oblock);
+ }
+}
+
+static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock)
+{
+ if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) {
+ policy_clear_dirty(cache->policy, oblock);
+ cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) - 1);
+ if (!from_cblock(cache->nr_dirty))
+ dm_table_event(cache->ti->table);
+ }
+}
+
+/*----------------------------------------------------------------*/
+static bool block_size_is_power_of_two(struct cache *cache)
+{
+ return cache->sectors_per_block_shift >= 0;
+}
+
+static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock)
+{
+ sector_t discard_blocks = cache->discard_block_size;
+ dm_block_t b = from_oblock(oblock);
+
+ if (!block_size_is_power_of_two(cache))
+ (void) sector_div(discard_blocks, cache->sectors_per_block);
+ else
+ discard_blocks >>= cache->sectors_per_block_shift;
+
+ (void) sector_div(b, discard_blocks);
+
+ return to_dblock(b);
+}
+
+static void set_discard(struct cache *cache, dm_dblock_t b)
+{
+ unsigned long flags;
+
+ atomic_inc(&cache->stats.discard_count);
+
+ spin_lock_irqsave(&cache->lock, flags);
+ set_bit(from_dblock(b), cache->discard_bitset);
+ spin_unlock_irqrestore(&cache->lock, flags);
+}
+
+static void clear_discard(struct cache *cache, dm_dblock_t b)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&cache->lock, flags);
+ clear_bit(from_dblock(b), cache->discard_bitset);
+ spin_unlock_irqrestore(&cache->lock, flags);
+}
+
+static bool is_discarded(struct cache *cache, dm_dblock_t b)
+{
+ int r;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cache->lock, flags);
+ r = test_bit(from_dblock(b), cache->discard_bitset);
+ spin_unlock_irqrestore(&cache->lock, flags);
+
+ return r;
+}
+
+static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b)
+{
+ int r;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cache->lock, flags);
+ r = test_bit(from_dblock(oblock_to_dblock(cache, b)),
+ cache->discard_bitset);
+ spin_unlock_irqrestore(&cache->lock, flags);
+
+ return r;
+}
+
+/*----------------------------------------------------------------*/
+
+static void load_stats(struct cache *cache)
+{
+ struct dm_cache_statistics stats;
+
+ dm_cache_metadata_get_stats(cache->cmd, &stats);
+ atomic_set(&cache->stats.read_hit, stats.read_hits);
+ atomic_set(&cache->stats.read_miss, stats.read_misses);
+ atomic_set(&cache->stats.write_hit, stats.write_hits);
+ atomic_set(&cache->stats.write_miss, stats.write_misses);
+}
+
+static void save_stats(struct cache *cache)
+{
+ struct dm_cache_statistics stats;
+
+ stats.read_hits = atomic_read(&cache->stats.read_hit);
+ stats.read_misses = atomic_read(&cache->stats.read_miss);
+ stats.write_hits = atomic_read(&cache->stats.write_hit);
+ stats.write_misses = atomic_read(&cache->stats.write_miss);
+
+ dm_cache_metadata_set_stats(cache->cmd, &stats);
+}
+
+/*----------------------------------------------------------------
+ * Per bio data
+ *--------------------------------------------------------------*/
+static struct per_bio_data *get_per_bio_data(struct bio *bio)
+{
+ struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
+ BUG_ON(!pb);
+ return pb;
+}
+
+static struct per_bio_data *init_per_bio_data(struct bio *bio)
+{
+ struct per_bio_data *pb = get_per_bio_data(bio);
+
+ pb->tick = false;
+ pb->req_nr = dm_bio_get_target_bio_nr(bio);
+ pb->all_io_entry = NULL;
+
+ return pb;
+}
+
+/*----------------------------------------------------------------
+ * Remapping
+ *--------------------------------------------------------------*/
+static void remap_to_origin(struct cache *cache, struct bio *bio)
+{
+ bio->bi_bdev = cache->origin_dev->bdev;
+}
+
+static void remap_to_cache(struct cache *cache, struct bio *bio,
+ dm_cblock_t cblock)
+{
+ sector_t bi_sector = bio->bi_sector;
+
+ bio->bi_bdev = cache->cache_dev->bdev;
+ if (!block_size_is_power_of_two(cache))
+ bio->bi_sector = (from_cblock(cblock) * cache->sectors_per_block) +
+ sector_div(bi_sector, cache->sectors_per_block);
+ else
+ bio->bi_sector = (from_cblock(cblock) << cache->sectors_per_block_shift) |
+ (bi_sector & (cache->sectors_per_block - 1));
+}
+
+static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio)
+{
+ unsigned long flags;
+ struct per_bio_data *pb = get_per_bio_data(bio);
+
+ spin_lock_irqsave(&cache->lock, flags);
+ if (cache->need_tick_bio &&
+ !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) {
+ pb->tick = true;
+ cache->need_tick_bio = false;
+ }
+ spin_unlock_irqrestore(&cache->lock, flags);
+}
+
+static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio,
+ dm_oblock_t oblock)
+{
+ check_if_tick_bio_needed(cache, bio);
+ remap_to_origin(cache, bio);
+ if (bio_data_dir(bio) == WRITE)
+ clear_discard(cache, oblock_to_dblock(cache, oblock));
+}
+
+static void remap_to_cache_dirty(struct cache *cache, struct bio *bio,
+ dm_oblock_t oblock, dm_cblock_t cblock)
+{
+ remap_to_cache(cache, bio, cblock);
+ if (bio_data_dir(bio) == WRITE) {
+ set_dirty(cache, oblock, cblock);
+ clear_discard(cache, oblock_to_dblock(cache, oblock));
+ }
+}
+
+static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio)
+{
+ sector_t block_nr = bio->bi_sector;
+
+ if (!block_size_is_power_of_two(cache))
+ (void) sector_div(block_nr, cache->sectors_per_block);
+ else
+ block_nr >>= cache->sectors_per_block_shift;
+
+ return to_oblock(block_nr);
+}
+
+static int bio_triggers_commit(struct cache *cache, struct bio *bio)
+{
+ return bio->bi_rw & (REQ_FLUSH | REQ_FUA);
+}
+
+static void issue(struct cache *cache, struct bio *bio)
+{
+ unsigned long flags;
+
+ if (!bio_triggers_commit(cache, bio)) {
+ generic_make_request(bio);
+ return;
+ }
+
+ /*
+ * Batch together any bios that trigger commits and then issue a
+ * single commit for them in do_worker().
+ */
+ spin_lock_irqsave(&cache->lock, flags);
+ cache->commit_requested = true;
+ bio_list_add(&cache->deferred_flush_bios, bio);
+ spin_unlock_irqrestore(&cache->lock, flags);
+}
+
+/*----------------------------------------------------------------
+ * Migration processing
+ *
+ * Migration covers moving data from the origin device to the cache, or
+ * vice versa.
+ *--------------------------------------------------------------*/
+static void free_migration(struct dm_cache_migration *mg)
+{
+ mempool_free(mg, mg->cache->migration_pool);
+}
+
+static void inc_nr_migrations(struct cache *cache)
+{
+ atomic_inc(&cache->nr_migrations);
+}
+
+static void dec_nr_migrations(struct cache *cache)
+{
+ atomic_dec(&cache->nr_migrations);
+
+ /*
+ * Wake the worker in case we're suspending the target.
+ */
+ wake_up(&cache->migration_wait);
+}
+
+static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
+ bool holder)
+{
+ (holder ? dm_cell_release : dm_cell_release_no_holder)
+ (cache->prison, cell, &cache->deferred_bios);
+ free_prison_cell(cache, cell);
+}
+
+static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
+ bool holder)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&cache->lock, flags);
+ __cell_defer(cache, cell, holder);
+ spin_unlock_irqrestore(&cache->lock, flags);
+
+ wake_worker(cache);
+}
+
+static void cleanup_migration(struct dm_cache_migration *mg)
+{
+ dec_nr_migrations(mg->cache);
+ free_migration(mg);
+}
+
+static void migration_failure(struct dm_cache_migration *mg)
+{
+ struct cache *cache = mg->cache;
+
+ if (mg->writeback) {
+ DMWARN_LIMIT("writeback failed; couldn't copy block");
+ set_dirty(cache, mg->old_oblock, mg->cblock);
+ cell_defer(cache, mg->old_ocell, false);
+
+ } else if (mg->demote) {
+ DMWARN_LIMIT("demotion failed; couldn't copy block");
+ policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock);
+
+ cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1);
+ if (mg->promote)
+ cell_defer(cache, mg->new_ocell, 1);
+ } else {
+ DMWARN_LIMIT("promotion failed; couldn't copy block");
+ policy_remove_mapping(cache->policy, mg->new_oblock);
+ cell_defer(cache, mg->new_ocell, 1);
+ }
+
+ cleanup_migration(mg);
+}
+
+static void migration_success_pre_commit(struct dm_cache_migration *mg)
+{
+ unsigned long flags;
+ struct cache *cache = mg->cache;
+
+ if (mg->writeback) {
+ cell_defer(cache, mg->old_ocell, false);
+ clear_dirty(cache, mg->old_oblock, mg->cblock);
+ cleanup_migration(mg);
+ return;
+
+ } else if (mg->demote) {
+ if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) {
+ DMWARN_LIMIT("demotion failed; couldn't update on disk metadata");
+ policy_force_mapping(cache->policy, mg->new_oblock,
+ mg->old_oblock);
+ if (mg->promote)
+ cell_defer(cache, mg->new_ocell, true);
+ cleanup_migration(mg);
+ return;
+ }
+ } else {
+ if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) {
+ DMWARN_LIMIT("promotion failed; couldn't update on disk metadata");
+ policy_remove_mapping(cache->policy, mg->new_oblock);
+ cleanup_migration(mg);
+ return;
+ }
+ }
+
+ spin_lock_irqsave(&cache->lock, flags);
+ list_add_tail(&mg->list, &cache->need_commit_migrations);
+ cache->commit_requested = true;
+ spin_unlock_irqrestore(&cache->lock, flags);
+}
+
+static void migration_success_post_commit(struct dm_cache_migration *mg)
+{
+ unsigned long flags;
+ struct cache *cache = mg->cache;
+
+ if (mg->writeback) {
+ DMWARN("writeback unexpectedly triggered commit");
+ return;
+
+ } else if (mg->demote) {
+ cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1);
+
+ if (mg->promote) {
+ mg->demote = false;
+
+ spin_lock_irqsave(&cache->lock, flags);
+ list_add_tail(&mg->list, &cache->quiesced_migrations);
+ spin_unlock_irqrestore(&cache->lock, flags);
+
+ } else
+ cleanup_migration(mg);
+
+ } else {
+ cell_defer(cache, mg->new_ocell, true);
+ clear_dirty(cache, mg->new_oblock, mg->cblock);
+ cleanup_migration(mg);
+ }
+}
+
+static void copy_complete(int read_err, unsigned long write_err, void *context)
+{
+ unsigned long flags;
+ struct dm_cache_migration *mg = (struct dm_cache_migration *) context;
+ struct cache *cache = mg->cache;
+
+ if (read_err || write_err)
+ mg->err = true;
+
+ spin_lock_irqsave(&cache->lock, flags);
+ list_add_tail(&mg->list, &cache->completed_migrations);
+ spin_unlock_irqrestore(&cache->lock, flags);
+
+ wake_worker(cache);
+}
+
+static void issue_copy_real(struct dm_cache_migration *mg)
+{
+ int r;
+ struct dm_io_region o_region, c_region;
+ struct cache *cache = mg->cache;
+
+ o_region.bdev = cache->origin_dev->bdev;
+ o_region.count = cache->sectors_per_block;
+
+ c_region.bdev = cache->cache_dev->bdev;
+ c_region.sector = from_cblock(mg->cblock) * cache->sectors_per_block;
+ c_region.count = cache->sectors_per_block;
+
+ if (mg->writeback || mg->demote) {
+ /* demote */
+ o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block;
+ r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg);
+ } else {
+ /* promote */
+ o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block;
+ r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg);
+ }
+
+ if (r < 0)
+ migration_failure(mg);
+}
+
+static void avoid_copy(struct dm_cache_migration *mg)
+{
+ atomic_inc(&mg->cache->stats.copies_avoided);
+ migration_success_pre_commit(mg);
+}
+
+static void issue_copy(struct dm_cache_migration *mg)
+{
+ bool avoid;
+ struct cache *cache = mg->cache;
+
+ if (mg->writeback || mg->demote)
+ avoid = !is_dirty(cache, mg->cblock) ||
+ is_discarded_oblock(cache, mg->old_oblock);
+ else
+ avoid = is_discarded_oblock(cache, mg->new_oblock);
+
+ avoid ? avoid_copy(mg) : issue_copy_real(mg);
+}
+
+static void complete_migration(struct dm_cache_migration *mg)
+{
+ if (mg->err)
+ migration_failure(mg);
+ else
+ migration_success_pre_commit(mg);
+}
+
+static void process_migrations(struct cache *cache, struct list_head *head,
+ void (*fn)(struct dm_cache_migration *))
+{
+ unsigned long flags;
+ struct list_head list;
+ struct dm_cache_migration *mg, *tmp;
+
+ INIT_LIST_HEAD(&list);
+ spin_lock_irqsave(&cache->lock, flags);
+ list_splice_init(head, &list);
+ spin_unlock_irqrestore(&cache->lock, flags);
+
+ list_for_each_entry_safe(mg, tmp, &list, list)
+ fn(mg);
+}
+
+static void __queue_quiesced_migration(struct dm_cache_migration *mg)
+{
+ list_add_tail(&mg->list, &mg->cache->quiesced_migrations);
+}
+
+static void queue_quiesced_migration(struct dm_cache_migration *mg)
+{
+ unsigned long flags;
+ struct cache *cache = mg->cache;
+
+ spin_lock_irqsave(&cache->lock, flags);
+ __queue_quiesced_migration(mg);
+ spin_unlock_irqrestore(&cache->lock, flags);
+
+ wake_worker(cache);
+}
+
+static void queue_quiesced_migrations(struct cache *cache, struct list_head *work)
+{
+ unsigned long flags;
+ struct dm_cache_migration *mg, *tmp;
+
+ spin_lock_irqsave(&cache->lock, flags);
+ list_for_each_entry_safe(mg, tmp, work, list)
+ __queue_quiesced_migration(mg);
+ spin_unlock_irqrestore(&cache->lock, flags);
+
+ wake_worker(cache);
+}
+
+static void check_for_quiesced_migrations(struct cache *cache,
+ struct per_bio_data *pb)
+{
+ struct list_head work;
+
+ if (!pb->all_io_entry)
+ return;
+
+ INIT_LIST_HEAD(&work);
+ if (pb->all_io_entry)
+ dm_deferred_entry_dec(pb->all_io_entry, &work);
+
+ if (!list_empty(&work))
+ queue_quiesced_migrations(cache, &work);
+}
+
+static void quiesce_migration(struct dm_cache_migration *mg)
+{
+ if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list))
+ queue_quiesced_migration(mg);
+}
+
+static void promote(struct cache *cache, struct prealloc *structs,
+ dm_oblock_t oblock, dm_cblock_t cblock,
+ struct dm_bio_prison_cell *cell)
+{
+ struct dm_cache_migration *mg = prealloc_get_migration(structs);
+
+ mg->err = false;
+ mg->writeback = false;
+ mg->demote = false;
+ mg->promote = true;
+ mg->cache = cache;
+ mg->new_oblock = oblock;
+ mg->cblock = cblock;
+ mg->old_ocell = NULL;
+ mg->new_ocell = cell;
+ mg->start_jiffies = jiffies;
+
+ inc_nr_migrations(cache);
+ quiesce_migration(mg);
+}
+
+static void writeback(struct cache *cache, struct prealloc *structs,
+ dm_oblock_t oblock, dm_cblock_t cblock,
+ struct dm_bio_prison_cell *cell)
+{
+ struct dm_cache_migration *mg = prealloc_get_migration(structs);
+
+ mg->err = false;
+ mg->writeback = true;
+ mg->demote = false;
+ mg->promote = false;
+ mg->cache = cache;
+ mg->old_oblock = oblock;
+ mg->cblock = cblock;
+ mg->old_ocell = cell;
+ mg->new_ocell = NULL;
+ mg->start_jiffies = jiffies;
+
+ inc_nr_migrations(cache);
+ quiesce_migration(mg);
+}
+
+static void demote_then_promote(struct cache *cache, struct prealloc *structs,
+ dm_oblock_t old_oblock, dm_oblock_t new_oblock,
+ dm_cblock_t cblock,
+ struct dm_bio_prison_cell *old_ocell,
+ struct dm_bio_prison_cell *new_ocell)
+{
+ struct dm_cache_migration *mg = prealloc_get_migration(structs);
+
+ mg->err = false;
+ mg->writeback = false;
+ mg->demote = true;
+ mg->promote = true;
+ mg->cache = cache;
+ mg->old_oblock = old_oblock;
+ mg->new_oblock = new_oblock;
+ mg->cblock = cblock;
+ mg->old_ocell = old_ocell;
+ mg->new_ocell = new_ocell;
+ mg->start_jiffies = jiffies;
+
+ inc_nr_migrations(cache);
+ quiesce_migration(mg);
+}
+
+/*----------------------------------------------------------------
+ * bio processing
+ *--------------------------------------------------------------*/
+static void defer_bio(struct cache *cache, struct bio *bio)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&cache->lock, flags);
+ bio_list_add(&cache->deferred_bios, bio);
+ spin_unlock_irqrestore(&cache->lock, flags);
+
+ wake_worker(cache);
+}
+
+static void process_flush_bio(struct cache *cache, struct bio *bio)
+{
+ struct per_bio_data *pb = get_per_bio_data(bio);
+
+ BUG_ON(bio->bi_size);
+ if (!pb->req_nr)
+ remap_to_origin(cache, bio);
+ else
+ remap_to_cache(cache, bio, 0);
+
+ issue(cache, bio);
+}
+
+/*
+ * People generally discard large parts of a device, eg, the whole device
+ * when formatting. Splitting these large discards up into cache block
+ * sized ios and then quiescing (always neccessary for discard) takes too
+ * long.
+ *
+ * We keep it simple, and allow any size of discard to come in, and just
+ * mark off blocks on the discard bitset. No passdown occurs!
+ *
+ * To implement passdown we need to change the bio_prison such that a cell
+ * can have a key that spans many blocks.
+ */
+static void process_discard_bio(struct cache *cache, struct bio *bio)
+{
+ dm_block_t start_block = dm_sector_div_up(bio->bi_sector,
+ cache->discard_block_size);
+ dm_block_t end_block = bio->bi_sector + bio_sectors(bio);
+ dm_block_t b;
+
+ (void) sector_div(end_block, cache->discard_block_size);
+
+ for (b = start_block; b < end_block; b++)
+ set_discard(cache, to_dblock(b));
+
+ bio_endio(bio, 0);
+}
+
+static bool spare_migration_bandwidth(struct cache *cache)
+{
+ sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) *
+ cache->sectors_per_block;
+ return current_volume < cache->migration_threshold;
+}
+
+static bool is_writethrough_io(struct cache *cache, struct bio *bio,
+ dm_cblock_t cblock)
+{
+ return bio_data_dir(bio) == WRITE &&
+ cache->features.write_through && !is_dirty(cache, cblock);
+}
+
+static void inc_hit_counter(struct cache *cache, struct bio *bio)
+{
+ atomic_inc(bio_data_dir(bio) == READ ?
+ &cache->stats.read_hit : &cache->stats.write_hit);
+}
+
+static void inc_miss_counter(struct cache *cache, struct bio *bio)
+{
+ atomic_inc(bio_data_dir(bio) == READ ?
+ &cache->stats.read_miss : &cache->stats.write_miss);
+}
+
+static void process_bio(struct cache *cache, struct prealloc *structs,
+ struct bio *bio)
+{
+ int r;
+ bool release_cell = true;
+ dm_oblock_t block = get_bio_block(cache, bio);
+ struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell;
+ struct policy_result lookup_result;
+ struct per_bio_data *pb = get_per_bio_data(bio);
+ bool discarded_block = is_discarded_oblock(cache, block);
+ bool can_migrate = discarded_block || spare_migration_bandwidth(cache);
+
+ /*
+ * Check to see if that block is currently migrating.
+ */
+ cell_prealloc = prealloc_get_cell(structs);
+ r = bio_detain(cache, block, bio, cell_prealloc,
+ (cell_free_fn) prealloc_put_cell,
+ structs, &new_ocell);
+ if (r > 0)
+ return;
+
+ r = policy_map(cache->policy, block, true, can_migrate, discarded_block,
+ bio, &lookup_result);
+
+ if (r == -EWOULDBLOCK)
+ /* migration has been denied */
+ lookup_result.op = POLICY_MISS;
+
+ switch (lookup_result.op) {
+ case POLICY_HIT:
+ inc_hit_counter(cache, bio);
+ pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
+
+ if (is_writethrough_io(cache, bio, lookup_result.cblock)) {
+ /*
+ * No need to mark anything dirty in write through mode.
+ */
+ pb->req_nr == 0 ?
+ remap_to_cache(cache, bio, lookup_result.cblock) :
+ remap_to_origin_clear_discard(cache, bio, block);
+ } else
+ remap_to_cache_dirty(cache, bio, block, lookup_result.cblock);
+
+ issue(cache, bio);
+ break;
+
+ case POLICY_MISS:
+ inc_miss_counter(cache, bio);
+ pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
+
+ if (pb->req_nr != 0) {
+ /*
+ * This is a duplicate writethrough io that is no
+ * longer needed because the block has been demoted.
+ */
+ bio_endio(bio, 0);
+ } else {
+ remap_to_origin_clear_discard(cache, bio, block);
+ issue(cache, bio);
+ }
+ break;
+
+ case POLICY_NEW:
+ atomic_inc(&cache->stats.promotion);
+ promote(cache, structs, block, lookup_result.cblock, new_ocell);
+ release_cell = false;
+ break;
+
+ case POLICY_REPLACE:
+ cell_prealloc = prealloc_get_cell(structs);
+ r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc,
+ (cell_free_fn) prealloc_put_cell,
+ structs, &old_ocell);
+ if (r > 0) {
+ /*
+ * We have to be careful to avoid lock inversion of
+ * the cells. So we back off, and wait for the
+ * old_ocell to become free.
+ */
+ policy_force_mapping(cache->policy, block,
+ lookup_result.old_oblock);
+ atomic_inc(&cache->stats.cache_cell_clash);
+ break;
+ }
+ atomic_inc(&cache->stats.demotion);
+ atomic_inc(&cache->stats.promotion);
+
+ demote_then_promote(cache, structs, lookup_result.old_oblock,
+ block, lookup_result.cblock,
+ old_ocell, new_ocell);
+ release_cell = false;
+ break;
+
+ default:
+ DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__,
+ (unsigned) lookup_result.op);
+ bio_io_error(bio);
+ }
+
+ if (release_cell)
+ cell_defer(cache, new_ocell, false);
+}
+
+static int need_commit_due_to_time(struct cache *cache)
+{
+ return jiffies < cache->last_commit_jiffies ||
+ jiffies > cache->last_commit_jiffies + COMMIT_PERIOD;
+}
+
+static int commit_if_needed(struct cache *cache)
+{
+ if (dm_cache_changed_this_transaction(cache->cmd) &&
+ (cache->commit_requested || need_commit_due_to_time(cache))) {
+ atomic_inc(&cache->stats.commit_count);
+ cache->last_commit_jiffies = jiffies;
+ cache->commit_requested = false;
+ return dm_cache_commit(cache->cmd, false);
+ }
+
+ return 0;
+}
+
+static void process_deferred_bios(struct cache *cache)
+{
+ unsigned long flags;
+ struct bio_list bios;
+ struct bio *bio;
+ struct prealloc structs;
+
+ memset(&structs, 0, sizeof(structs));
+ bio_list_init(&bios);
+
+ spin_lock_irqsave(&cache->lock, flags);
+ bio_list_merge(&bios, &cache->deferred_bios);
+ bio_list_init(&cache->deferred_bios);
+ spin_unlock_irqrestore(&cache->lock, flags);
+
+ while (!bio_list_empty(&bios)) {
+ /*
+ * If we've got no free migration structs, and processing
+ * this bio might require one, we pause until there are some
+ * prepared mappings to process.
+ */
+ if (prealloc_data_structs(cache, &structs)) {
+ spin_lock_irqsave(&cache->lock, flags);
+ bio_list_merge(&cache->deferred_bios, &bios);
+ spin_unlock_irqrestore(&cache->lock, flags);
+ break;
+ }
+
+ bio = bio_list_pop(&bios);
+
+ if (bio->bi_rw & REQ_FLUSH)
+ process_flush_bio(cache, bio);
+ else if (bio->bi_rw & REQ_DISCARD)
+ process_discard_bio(cache, bio);
+ else
+ process_bio(cache, &structs, bio);
+ }
+
+ prealloc_free_structs(cache, &structs);
+}
+
+static void process_deferred_flush_bios(struct cache *cache, bool submit_bios)
+{
+ unsigned long flags;
+ struct bio_list bios;
+ struct bio *bio;
+
+ bio_list_init(&bios);
+
+ spin_lock_irqsave(&cache->lock, flags);
+ bio_list_merge(&bios, &cache->deferred_flush_bios);
+ bio_list_init(&cache->deferred_flush_bios);
+ spin_unlock_irqrestore(&cache->lock, flags);
+
+ while ((bio = bio_list_pop(&bios)))
+ submit_bios ? generic_make_request(bio) : bio_io_error(bio);
+}
+
+static void writeback_some_dirty_blocks(struct cache *cache)
+{
+ int r = 0;
+ dm_oblock_t oblock;
+ dm_cblock_t cblock;
+ struct prealloc structs;
+ struct dm_bio_prison_cell *old_ocell;
+
+ memset(&structs, 0, sizeof(structs));
+
+ while (spare_migration_bandwidth(cache)) {
+ if (prealloc_data_structs(cache, &structs))
+ break;
+
+ r = policy_writeback_work(cache->policy, &oblock, &cblock);
+ if (r)
+ break;
+
+ r = get_cell(cache, oblock, &structs, &old_ocell);
+ if (r) {
+ policy_set_dirty(cache->policy, oblock);
+ break;
+ }
+
+ writeback(cache, &structs, oblock, cblock, old_ocell);
+ }
+
+ prealloc_free_structs(cache, &structs);
+}
+
+/*----------------------------------------------------------------
+ * Main worker loop
+ *--------------------------------------------------------------*/
+static void start_quiescing(struct cache *cache)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&cache->lock, flags);
+ cache->quiescing = 1;
+ spin_unlock_irqrestore(&cache->lock, flags);
+}
+
+static void stop_quiescing(struct cache *cache)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&cache->lock, flags);
+ cache->quiescing = 0;
+ spin_unlock_irqrestore(&cache->lock, flags);
+}
+
+static bool is_quiescing(struct cache *cache)
+{
+ int r;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cache->lock, flags);
+ r = cache->quiescing;
+ spin_unlock_irqrestore(&cache->lock, flags);
+
+ return r;
+}
+
+static void wait_for_migrations(struct cache *cache)
+{
+ wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations));
+}
+
+static void stop_worker(struct cache *cache)
+{
+ cancel_delayed_work(&cache->waker);
+ flush_workqueue(cache->wq);
+}
+
+static void requeue_deferred_io(struct cache *cache)
+{
+ struct bio *bio;
+ struct bio_list bios;
+
+ bio_list_init(&bios);
+ bio_list_merge(&bios, &cache->deferred_bios);
+ bio_list_init(&cache->deferred_bios);
+
+ while ((bio = bio_list_pop(&bios)))
+ bio_endio(bio, DM_ENDIO_REQUEUE);
+}
+
+static int more_work(struct cache *cache)
+{
+ if (is_quiescing(cache))
+ return !list_empty(&cache->quiesced_migrations) ||
+ !list_empty(&cache->completed_migrations) ||
+ !list_empty(&cache->need_commit_migrations);
+ else
+ return !bio_list_empty(&cache->deferred_bios) ||
+ !bio_list_empty(&cache->deferred_flush_bios) ||
+ !list_empty(&cache->quiesced_migrations) ||
+ !list_empty(&cache->completed_migrations) ||
+ !list_empty(&cache->need_commit_migrations);
+}
+
+static void do_worker(struct work_struct *ws)
+{
+ struct cache *cache = container_of(ws, struct cache, worker);
+
+ do {
+ if (!is_quiescing(cache))
+ process_deferred_bios(cache);
+
+ process_migrations(cache, &cache->quiesced_migrations, issue_copy);
+ process_migrations(cache, &cache->completed_migrations, complete_migration);
+
+ writeback_some_dirty_blocks(cache);
+
+ if (commit_if_needed(cache)) {
+ process_deferred_flush_bios(cache, false);
+
+ /*
+ * FIXME: rollback metadata or just go into a
+ * failure mode and error everything
+ */
+ } else {
+ process_deferred_flush_bios(cache, true);
+ process_migrations(cache, &cache->need_commit_migrations,
+ migration_success_post_commit);
+ }
+ } while (more_work(cache));
+}
+
+/*
+ * We want to commit periodically so that not too much
+ * unwritten metadata builds up.
+ */
+static void do_waker(struct work_struct *ws)
+{
+ struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker);
+ wake_worker(cache);
+ queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD);
+}
+
+/*----------------------------------------------------------------*/
+
+static int is_congested(struct dm_dev *dev, int bdi_bits)
+{
+ struct request_queue *q = bdev_get_queue(dev->bdev);
+ return bdi_congested(&q->backing_dev_info, bdi_bits);
+}
+
+static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
+{
+ struct cache *cache = container_of(cb, struct cache, callbacks);
+
+ return is_congested(cache->origin_dev, bdi_bits) ||
+ is_congested(cache->cache_dev, bdi_bits);
+}
+
+/*----------------------------------------------------------------
+ * Target methods
+ *--------------------------------------------------------------*/
+
+/*
+ * This function gets called on the error paths of the constructor, so we
+ * have to cope with a partially initialised struct.
+ */
+static void destroy(struct cache *cache)
+{
+ unsigned i;
+
+ if (cache->next_migration)
+ mempool_free(cache->next_migration, cache->migration_pool);
+
+ if (cache->migration_pool)
+ mempool_destroy(cache->migration_pool);
+
+ if (cache->all_io_ds)
+ dm_deferred_set_destroy(cache->all_io_ds);
+
+ if (cache->prison)
+ dm_bio_prison_destroy(cache->prison);
+
+ if (cache->wq)
+ destroy_workqueue(cache->wq);
+
+ if (cache->dirty_bitset)
+ free_bitset(cache->dirty_bitset);
+
+ if (cache->discard_bitset)
+ free_bitset(cache->discard_bitset);
+
+ if (cache->copier)
+ dm_kcopyd_client_destroy(cache->copier);
+
+ if (cache->cmd)
+ dm_cache_metadata_close(cache->cmd);
+
+ if (cache->metadata_dev)
+ dm_put_device(cache->ti, cache->metadata_dev);
+
+ if (cache->origin_dev)
+ dm_put_device(cache->ti, cache->origin_dev);
+
+ if (cache->cache_dev)
+ dm_put_device(cache->ti, cache->cache_dev);
+
+ if (cache->policy)
+ dm_cache_policy_destroy(cache->policy);
+
+ for (i = 0; i < cache->nr_ctr_args ; i++)
+ kfree(cache->ctr_args[i]);
+ kfree(cache->ctr_args);
+
+ kfree(cache);
+}
+
+static void cache_dtr(struct dm_target *ti)
+{
+ struct cache *cache = ti->private;
+
+ destroy(cache);
+}
+
+static sector_t get_dev_size(struct dm_dev *dev)
+{
+ return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Construct a cache device mapping.
+ *
+ * cache <metadata dev> <cache dev> <origin dev> <block size>
+ * <#feature args> [<feature arg>]*
+ * <policy> <#policy args> [<policy arg>]*
+ *
+ * metadata dev : fast device holding the persistent metadata
+ * cache dev : fast device holding cached data blocks
+ * origin dev : slow device holding original data blocks
+ * block size : cache unit size in sectors
+ *
+ * #feature args : number of feature arguments passed
+ * feature args : writethrough. (The default is writeback.)
+ *
+ * policy : the replacement policy to use
+ * #policy args : an even number of policy arguments corresponding
+ * to key/value pairs passed to the policy
+ * policy args : key/value pairs passed to the policy
+ * E.g. 'sequential_threshold 1024'
+ * See cache-policies.txt for details.
+ *
+ * Optional feature arguments are:
+ * writethrough : write through caching that prohibits cache block
+ * content from being different from origin block content.
+ * Without this argument, the default behaviour is to write
+ * back cache block contents later for performance reasons,
+ * so they may differ from the corresponding origin blocks.
+ */
+struct cache_args {
+ struct dm_target *ti;
+
+ struct dm_dev *metadata_dev;
+
+ struct dm_dev *cache_dev;
+ sector_t cache_sectors;
+
+ struct dm_dev *origin_dev;
+ sector_t origin_sectors;
+
+ uint32_t block_size;
+
+ const char *policy_name;
+ int policy_argc;
+ const char **policy_argv;
+
+ struct cache_features features;
+};
+
+static void destroy_cache_args(struct cache_args *ca)
+{
+ if (ca->metadata_dev)
+ dm_put_device(ca->ti, ca->metadata_dev);
+
+ if (ca->cache_dev)
+ dm_put_device(ca->ti, ca->cache_dev);
+
+ if (ca->origin_dev)
+ dm_put_device(ca->ti, ca->origin_dev);
+
+ kfree(ca);
+}
+
+static bool at_least_one_arg(struct dm_arg_set *as, char **error)
+{
+ if (!as->argc) {
+ *error = "Insufficient args";
+ return false;
+ }
+
+ return true;
+}
+
+static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as,
+ char **error)
+{
+ int r;
+ sector_t metadata_dev_size;
+ char b[BDEVNAME_SIZE];
+
+ if (!at_least_one_arg(as, error))
+ return -EINVAL;
+
+ r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
+ &ca->metadata_dev);
+ if (r) {
+ *error = "Error opening metadata device";
+ return r;
+ }
+
+ metadata_dev_size = get_dev_size(ca->metadata_dev);
+ if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING)
+ DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
+ bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
+
+ return 0;
+}
+
+static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as,
+ char **error)
+{
+ int r;
+
+ if (!at_least_one_arg(as, error))
+ return -EINVAL;
+
+ r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
+ &ca->cache_dev);
+ if (r) {
+ *error = "Error opening cache device";
+ return r;
+ }
+ ca->cache_sectors = get_dev_size(ca->cache_dev);
+
+ return 0;
+}
+
+static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as,
+ char **error)
+{
+ int r;
+
+ if (!at_least_one_arg(as, error))
+ return -EINVAL;
+
+ r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
+ &ca->origin_dev);
+ if (r) {
+ *error = "Error opening origin device";
+ return r;
+ }
+
+ ca->origin_sectors = get_dev_size(ca->origin_dev);
+ if (ca->ti->len > ca->origin_sectors) {
+ *error = "Device size larger than cached device";
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as,
+ char **error)
+{
+ unsigned long tmp;
+
+ if (!at_least_one_arg(as, error))
+ return -EINVAL;
+
+ if (kstrtoul(dm_shift_arg(as), 10, &tmp) || !tmp ||
+ tmp < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
+ tmp & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
+ *error = "Invalid data block size";
+ return -EINVAL;
+ }
+
+ if (tmp > ca->cache_sectors) {
+ *error = "Data block size is larger than the cache device";
+ return -EINVAL;
+ }
+
+ ca->block_size = tmp;
+
+ return 0;
+}
+
+static void init_features(struct cache_features *cf)
+{
+ cf->mode = CM_WRITE;
+ cf->write_through = false;
+}
+
+static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
+ char **error)
+{
+ static struct dm_arg _args[] = {
+ {0, 1, "Invalid number of cache feature arguments"},
+ };
+
+ int r;
+ unsigned argc;
+ const char *arg;
+ struct cache_features *cf = &ca->features;
+
+ init_features(cf);
+
+ r = dm_read_arg_group(_args, as, &argc, error);
+ if (r)
+ return -EINVAL;
+
+ while (argc--) {
+ arg = dm_shift_arg(as);
+
+ if (!strcasecmp(arg, "writeback"))
+ cf->write_through = false;
+
+ else if (!strcasecmp(arg, "writethrough"))
+ cf->write_through = true;
+
+ else {
+ *error = "Unrecognised cache feature requested";
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static int parse_policy(struct cache_args *ca, struct dm_arg_set *as,
+ char **error)
+{
+ static struct dm_arg _args[] = {
+ {0, 1024, "Invalid number of policy arguments"},
+ };
+
+ int r;
+
+ if (!at_least_one_arg(as, error))
+ return -EINVAL;
+
+ ca->policy_name = dm_shift_arg(as);
+
+ r = dm_read_arg_group(_args, as, &ca->policy_argc, error);
+ if (r)
+ return -EINVAL;
+
+ ca->policy_argv = (const char **)as->argv;
+ dm_consume_args(as, ca->policy_argc);
+
+ return 0;
+}
+
+static int parse_cache_args(struct cache_args *ca, int argc, char **argv,
+ char **error)
+{
+ int r;
+ struct dm_arg_set as;
+
+ as.argc = argc;
+ as.argv = argv;
+
+ r = parse_metadata_dev(ca, &as, error);
+ if (r)
+ return r;
+
+ r = parse_cache_dev(ca, &as, error);
+ if (r)
+ return r;
+
+ r = parse_origin_dev(ca, &as, error);
+ if (r)
+ return r;
+
+ r = parse_block_size(ca, &as, error);
+ if (r)
+ return r;
+
+ r = parse_features(ca, &as, error);
+ if (r)
+ return r;
+
+ r = parse_policy(ca, &as, error);
+ if (r)
+ return r;
+
+ return 0;
+}
+
+/*----------------------------------------------------------------*/
+
+static struct kmem_cache *migration_cache;
+
+static int set_config_values(struct dm_cache_policy *p, int argc, const char **argv)
+{
+ int r = 0;
+
+ if (argc & 1) {
+ DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs.");
+ return -EINVAL;
+ }
+
+ while (argc) {
+ r = policy_set_config_value(p, argv[0], argv[1]);
+ if (r) {
+ DMWARN("policy_set_config_value failed: key = '%s', value = '%s'",
+ argv[0], argv[1]);
+ return r;
+ }
+
+ argc -= 2;
+ argv += 2;
+ }
+
+ return r;
+}
+
+static int create_cache_policy(struct cache *cache, struct cache_args *ca,
+ char **error)
+{
+ int r;
+
+ cache->policy = dm_cache_policy_create(ca->policy_name,
+ cache->cache_size,
+ cache->origin_sectors,
+ cache->sectors_per_block);
+ if (!cache->policy) {
+ *error = "Error creating cache's policy";
+ return -ENOMEM;
+ }
+
+ r = set_config_values(cache->policy, ca->policy_argc, ca->policy_argv);
+ if (r)
+ dm_cache_policy_destroy(cache->policy);
+
+ return r;
+}
+
+/*
+ * We want the discard block size to be a power of two, at least the size
+ * of the cache block size, and have no more than 2^14 discard blocks
+ * across the origin.
+ */
+#define MAX_DISCARD_BLOCKS (1 << 14)
+
+static bool too_many_discard_blocks(sector_t discard_block_size,
+ sector_t origin_size)
+{
+ (void) sector_div(origin_size, discard_block_size);
+
+ return origin_size > MAX_DISCARD_BLOCKS;
+}
+
+static sector_t calculate_discard_block_size(sector_t cache_block_size,
+ sector_t origin_size)
+{
+ sector_t discard_block_size;
+
+ discard_block_size = roundup_pow_of_two(cache_block_size);
+
+ if (origin_size)
+ while (too_many_discard_blocks(discard_block_size, origin_size))
+ discard_block_size *= 2;
+
+ return discard_block_size;
+}
+
+#define DEFAULT_MIGRATION_THRESHOLD (2048 * 100)
+
+static unsigned cache_num_write_bios(struct dm_target *ti, struct bio *bio);
+
+static int cache_create(struct cache_args *ca, struct cache **result)
+{
+ int r = 0;
+ char **error = &ca->ti->error;
+ struct cache *cache;
+ struct dm_target *ti = ca->ti;
+ dm_block_t origin_blocks;
+ struct dm_cache_metadata *cmd;
+ bool may_format = ca->features.mode == CM_WRITE;
+
+ cache = kzalloc(sizeof(*cache), GFP_KERNEL);
+ if (!cache)
+ return -ENOMEM;
+
+ cache->ti = ca->ti;
+ ti->private = cache;
+ ti->per_bio_data_size = sizeof(struct per_bio_data);
+ ti->num_flush_bios = 2;
+ ti->flush_supported = true;
+
+ ti->num_discard_bios = 1;
+ ti->discards_supported = true;
+ ti->discard_zeroes_data_unsupported = true;
+
+ memcpy(&cache->features, &ca->features, sizeof(cache->features));
+
+ if (cache->features.write_through)
+ ti->num_write_bios = cache_num_write_bios;
+
+ cache->callbacks.congested_fn = cache_is_congested;
+ dm_table_add_target_callbacks(ti->table, &cache->callbacks);
+
+ cache->metadata_dev = ca->metadata_dev;
+ cache->origin_dev = ca->origin_dev;
+ cache->cache_dev = ca->cache_dev;
+
+ ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL;
+
+ /* FIXME: factor out this whole section */
+ origin_blocks = cache->origin_sectors = ca->origin_sectors;
+ (void) sector_div(origin_blocks, ca->block_size);
+ cache->origin_blocks = to_oblock(origin_blocks);
+
+ cache->sectors_per_block = ca->block_size;
+ if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) {
+ r = -EINVAL;
+ goto bad;
+ }
+
+ if (ca->block_size & (ca->block_size - 1)) {
+ dm_block_t cache_size = ca->cache_sectors;
+
+ cache->sectors_per_block_shift = -1;
+ (void) sector_div(cache_size, ca->block_size);
+ cache->cache_size = to_cblock(cache_size);
+ } else {
+ cache->sectors_per_block_shift = __ffs(ca->block_size);
+ cache->cache_size = to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift);
+ }
+
+ r = create_cache_policy(cache, ca, error);
+ if (r)
+ goto bad;
+ cache->policy_nr_args = ca->policy_argc;
+
+ cmd = dm_cache_metadata_open(cache->metadata_dev->bdev,
+ ca->block_size, may_format,
+ dm_cache_policy_get_hint_size(cache->policy));
+ if (IS_ERR(cmd)) {
+ *error = "Error creating metadata object";
+ r = PTR_ERR(cmd);
+ goto bad;
+ }
+ cache->cmd = cmd;
+
+ spin_lock_init(&cache->lock);
+ bio_list_init(&cache->deferred_bios);
+ bio_list_init(&cache->deferred_flush_bios);
+ INIT_LIST_HEAD(&cache->quiesced_migrations);
+ INIT_LIST_HEAD(&cache->completed_migrations);
+ INIT_LIST_HEAD(&cache->need_commit_migrations);
+ cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD;
+ atomic_set(&cache->nr_migrations, 0);
+ init_waitqueue_head(&cache->migration_wait);
+
+ cache->nr_dirty = 0;
+ cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size));
+ if (!cache->dirty_bitset) {
+ *error = "could not allocate dirty bitset";
+ goto bad;
+ }
+ clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size));
+
+ cache->discard_block_size =
+ calculate_discard_block_size(cache->sectors_per_block,
+ cache->origin_sectors);
+ cache->discard_nr_blocks = oblock_to_dblock(cache, cache->origin_blocks);
+ cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks));
+ if (!cache->discard_bitset) {
+ *error = "could not allocate discard bitset";
+ goto bad;
+ }
+ clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks));
+
+ cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
+ if (IS_ERR(cache->copier)) {
+ *error = "could not create kcopyd client";
+ r = PTR_ERR(cache->copier);
+ goto bad;
+ }
+
+ cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
+ if (!cache->wq) {
+ *error = "could not create workqueue for metadata object";
+ goto bad;
+ }
+ INIT_WORK(&cache->worker, do_worker);
+ INIT_DELAYED_WORK(&cache->waker, do_waker);
+ cache->last_commit_jiffies = jiffies;
+
+ cache->prison = dm_bio_prison_create(PRISON_CELLS);
+ if (!cache->prison) {
+ *error = "could not create bio prison";
+ goto bad;
+ }
+
+ cache->all_io_ds = dm_deferred_set_create();
+ if (!cache->all_io_ds) {
+ *error = "could not create all_io deferred set";
+ goto bad;
+ }
+
+ cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE,
+ migration_cache);
+ if (!cache->migration_pool) {
+ *error = "Error creating cache's migration mempool";
+ goto bad;
+ }
+
+ cache->next_migration = NULL;
+
+ cache->need_tick_bio = true;
+ cache->sized = false;
+ cache->quiescing = false;
+ cache->commit_requested = false;
+ cache->loaded_mappings = false;
+ cache->loaded_discards = false;
+
+ load_stats(cache);
+
+ atomic_set(&cache->stats.demotion, 0);
+ atomic_set(&cache->stats.promotion, 0);
+ atomic_set(&cache->stats.copies_avoided, 0);
+ atomic_set(&cache->stats.cache_cell_clash, 0);
+ atomic_set(&cache->stats.commit_count, 0);
+ atomic_set(&cache->stats.discard_count, 0);
+
+ *result = cache;
+ return 0;
+
+bad:
+ destroy(cache);
+ return r;
+}
+
+static int copy_ctr_args(struct cache *cache, int argc, const char **argv)
+{
+ unsigned i;
+ const char **copy;
+
+ copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL);
+ if (!copy)
+ return -ENOMEM;
+ for (i = 0; i < argc; i++) {
+ copy[i] = kstrdup(argv[i], GFP_KERNEL);
+ if (!copy[i]) {
+ while (i--)
+ kfree(copy[i]);
+ kfree(copy);
+ return -ENOMEM;
+ }
+ }
+
+ cache->nr_ctr_args = argc;
+ cache->ctr_args = copy;
+
+ return 0;
+}
+
+static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv)
+{
+ int r = -EINVAL;
+ struct cache_args *ca;
+ struct cache *cache = NULL;
+
+ ca = kzalloc(sizeof(*ca), GFP_KERNEL);
+ if (!ca) {
+ ti->error = "Error allocating memory for cache";
+ return -ENOMEM;
+ }
+ ca->ti = ti;
+
+ r = parse_cache_args(ca, argc, argv, &ti->error);
+ if (r)
+ goto out;
+
+ r = cache_create(ca, &cache);
+
+ r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3);
+ if (r) {
+ destroy(cache);
+ goto out;
+ }
+
+ ti->private = cache;
+
+out:
+ destroy_cache_args(ca);
+ return r;
+}
+
+static unsigned cache_num_write_bios(struct dm_target *ti, struct bio *bio)
+{
+ int r;
+ struct cache *cache = ti->private;
+ dm_oblock_t block = get_bio_block(cache, bio);
+ dm_cblock_t cblock;
+
+ r = policy_lookup(cache->policy, block, &cblock);
+ if (r < 0)
+ return 2; /* assume the worst */
+
+ return (!r && !is_dirty(cache, cblock)) ? 2 : 1;
+}
+
+static int cache_map(struct dm_target *ti, struct bio *bio)
+{
+ struct cache *cache = ti->private;
+
+ int r;
+ dm_oblock_t block = get_bio_block(cache, bio);
+ bool can_migrate = false;
+ bool discarded_block;
+ struct dm_bio_prison_cell *cell;
+ struct policy_result lookup_result;
+ struct per_bio_data *pb;
+
+ if (from_oblock(block) > from_oblock(cache->origin_blocks)) {
+ /*
+ * This can only occur if the io goes to a partial block at
+ * the end of the origin device. We don't cache these.
+ * Just remap to the origin and carry on.
+ */
+ remap_to_origin_clear_discard(cache, bio, block);
+ return DM_MAPIO_REMAPPED;
+ }
+
+ pb = init_per_bio_data(bio);
+
+ if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) {
+ defer_bio(cache, bio);
+ return DM_MAPIO_SUBMITTED;
+ }
+
+ /*
+ * Check to see if that block is currently migrating.
+ */
+ cell = alloc_prison_cell(cache);
+ if (!cell) {
+ defer_bio(cache, bio);
+ return DM_MAPIO_SUBMITTED;
+ }
+
+ r = bio_detain(cache, block, bio, cell,
+ (cell_free_fn) free_prison_cell,
+ cache, &cell);
+ if (r) {
+ if (r < 0)
+ defer_bio(cache, bio);
+
+ return DM_MAPIO_SUBMITTED;
+ }
+
+ discarded_block = is_discarded_oblock(cache, block);
+
+ r = policy_map(cache->policy, block, false, can_migrate, discarded_block,
+ bio, &lookup_result);
+ if (r == -EWOULDBLOCK) {
+ cell_defer(cache, cell, true);
+ return DM_MAPIO_SUBMITTED;
+
+ } else if (r) {
+ DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r);
+ bio_io_error(bio);
+ return DM_MAPIO_SUBMITTED;
+ }
+
+ switch (lookup_result.op) {
+ case POLICY_HIT:
+ inc_hit_counter(cache, bio);
+ pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
+
+ if (is_writethrough_io(cache, bio, lookup_result.cblock)) {
+ /*
+ * No need to mark anything dirty in write through mode.
+ */
+ pb->req_nr == 0 ?
+ remap_to_cache(cache, bio, lookup_result.cblock) :
+ remap_to_origin_clear_discard(cache, bio, block);
+ cell_defer(cache, cell, false);
+ } else {
+ remap_to_cache_dirty(cache, bio, block, lookup_result.cblock);
+ cell_defer(cache, cell, false);
+ }
+ break;
+
+ case POLICY_MISS:
+ inc_miss_counter(cache, bio);
+ pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
+
+ if (pb->req_nr != 0) {
+ /*
+ * This is a duplicate writethrough io that is no
+ * longer needed because the block has been demoted.
+ */
+ bio_endio(bio, 0);
+ cell_defer(cache, cell, false);
+ return DM_MAPIO_SUBMITTED;
+ } else {
+ remap_to_origin_clear_discard(cache, bio, block);
+ cell_defer(cache, cell, false);
+ }
+ break;
+
+ default:
+ DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__,
+ (unsigned) lookup_result.op);
+ bio_io_error(bio);
+ return DM_MAPIO_SUBMITTED;
+ }
+
+ return DM_MAPIO_REMAPPED;
+}
+
+static int cache_end_io(struct dm_target *ti, struct bio *bio, int error)
+{
+ struct cache *cache = ti->private;
+ unsigned long flags;
+ struct per_bio_data *pb = get_per_bio_data(bio);
+
+ if (pb->tick) {
+ policy_tick(cache->policy);
+
+ spin_lock_irqsave(&cache->lock, flags);
+ cache->need_tick_bio = true;
+ spin_unlock_irqrestore(&cache->lock, flags);
+ }
+
+ check_for_quiesced_migrations(cache, pb);
+
+ return 0;
+}
+
+static int write_dirty_bitset(struct cache *cache)
+{
+ unsigned i, r;
+
+ for (i = 0; i < from_cblock(cache->cache_size); i++) {
+ r = dm_cache_set_dirty(cache->cmd, to_cblock(i),
+ is_dirty(cache, to_cblock(i)));
+ if (r)
+ return r;
+ }
+
+ return 0;
+}
+
+static int write_discard_bitset(struct cache *cache)
+{
+ unsigned i, r;
+
+ r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size,
+ cache->discard_nr_blocks);
+ if (r) {
+ DMERR("could not resize on-disk discard bitset");
+ return r;
+ }
+
+ for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) {
+ r = dm_cache_set_discard(cache->cmd, to_dblock(i),
+ is_discarded(cache, to_dblock(i)));
+ if (r)
+ return r;
+ }
+
+ return 0;
+}
+
+static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock,
+ uint32_t hint)
+{
+ struct cache *cache = context;
+ return dm_cache_save_hint(cache->cmd, cblock, hint);
+}
+
+static int write_hints(struct cache *cache)
+{
+ int r;
+
+ r = dm_cache_begin_hints(cache->cmd, cache->policy);
+ if (r) {
+ DMERR("dm_cache_begin_hints failed");
+ return r;
+ }
+
+ r = policy_walk_mappings(cache->policy, save_hint, cache);
+ if (r)
+ DMERR("policy_walk_mappings failed");
+
+ return r;
+}
+
+/*
+ * returns true on success
+ */
+static bool sync_metadata(struct cache *cache)
+{
+ int r1, r2, r3, r4;
+
+ r1 = write_dirty_bitset(cache);
+ if (r1)
+ DMERR("could not write dirty bitset");
+
+ r2 = write_discard_bitset(cache);
+ if (r2)
+ DMERR("could not write discard bitset");
+
+ save_stats(cache);
+
+ r3 = write_hints(cache);
+ if (r3)
+ DMERR("could not write hints");
+
+ /*
+ * If writing the above metadata failed, we still commit, but don't
+ * set the clean shutdown flag. This will effectively force every
+ * dirty bit to be set on reload.
+ */
+ r4 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3);
+ if (r4)
+ DMERR("could not write cache metadata. Data loss may occur.");
+
+ return !r1 && !r2 && !r3 && !r4;
+}
+
+static void cache_postsuspend(struct dm_target *ti)
+{
+ struct cache *cache = ti->private;
+
+ start_quiescing(cache);
+ wait_for_migrations(cache);
+ stop_worker(cache);
+ requeue_deferred_io(cache);
+ stop_quiescing(cache);
+
+ (void) sync_metadata(cache);
+}
+
+static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock,
+ bool dirty, uint32_t hint, bool hint_valid)
+{
+ int r;
+ struct cache *cache = context;
+
+ r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid);
+ if (r)
+ return r;
+
+ if (dirty)
+ set_dirty(cache, oblock, cblock);
+ else
+ clear_dirty(cache, oblock, cblock);
+
+ return 0;
+}
+
+static int load_discard(void *context, sector_t discard_block_size,
+ dm_dblock_t dblock, bool discard)
+{
+ struct cache *cache = context;
+
+ /* FIXME: handle mis-matched block size */
+
+ if (discard)
+ set_discard(cache, dblock);
+ else
+ clear_discard(cache, dblock);
+
+ return 0;
+}
+
+static int cache_preresume(struct dm_target *ti)
+{
+ int r = 0;
+ struct cache *cache = ti->private;
+ sector_t actual_cache_size = get_dev_size(cache->cache_dev);
+ (void) sector_div(actual_cache_size, cache->sectors_per_block);
+
+ /*
+ * Check to see if the cache has resized.
+ */
+ if (from_cblock(cache->cache_size) != actual_cache_size || !cache->sized) {
+ cache->cache_size = to_cblock(actual_cache_size);
+
+ r = dm_cache_resize(cache->cmd, cache->cache_size);
+ if (r) {
+ DMERR("could not resize cache metadata");
+ return r;
+ }
+
+ cache->sized = true;
+ }
+
+ if (!cache->loaded_mappings) {
+ r = dm_cache_load_mappings(cache->cmd,
+ dm_cache_policy_get_name(cache->policy),
+ load_mapping, cache);
+ if (r) {
+ DMERR("could not load cache mappings");
+ return r;
+ }
+
+ cache->loaded_mappings = true;
+ }
+
+ if (!cache->loaded_discards) {
+ r = dm_cache_load_discards(cache->cmd, load_discard, cache);
+ if (r) {
+ DMERR("could not load origin discards");
+ return r;
+ }
+
+ cache->loaded_discards = true;
+ }
+
+ return r;
+}
+
+static void cache_resume(struct dm_target *ti)
+{
+ struct cache *cache = ti->private;
+
+ cache->need_tick_bio = true;
+ do_waker(&cache->waker.work);
+}
+
+/*
+ * Status format:
+ *
+ * <#used metadata blocks>/<#total metadata blocks>
+ * <#read hits> <#read misses> <#write hits> <#write misses>
+ * <#demotions> <#promotions> <#blocks in cache> <#dirty>
+ * <#features> <features>*
+ * <#core args> <core args>
+ * <#policy args> <policy args>*
+ */
+static void cache_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
+{
+ int r = 0;
+ unsigned i;
+ ssize_t sz = 0;
+ dm_block_t nr_free_blocks_metadata = 0;
+ dm_block_t nr_blocks_metadata = 0;
+ char buf[BDEVNAME_SIZE];
+ struct cache *cache = ti->private;
+ dm_cblock_t residency;
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ /* Commit to ensure statistics aren't out-of-date */
+ if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) {
+ r = dm_cache_commit(cache->cmd, false);
+ if (r)
+ DMERR("could not commit metadata for accurate status");
+ }
+
+ r = dm_cache_get_free_metadata_block_count(cache->cmd,
+ &nr_free_blocks_metadata);
+ if (r) {
+ DMERR("could not get metadata free block count");
+ goto err;
+ }
+
+ r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata);
+ if (r) {
+ DMERR("could not get metadata device size");
+ goto err;
+ }
+
+ residency = policy_residency(cache->policy);
+
+ DMEMIT("%llu/%llu %u %u %u %u %u %u %llu %u ",
+ (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
+ (unsigned long long)nr_blocks_metadata,
+ (unsigned) atomic_read(&cache->stats.read_hit),
+ (unsigned) atomic_read(&cache->stats.read_miss),
+ (unsigned) atomic_read(&cache->stats.write_hit),
+ (unsigned) atomic_read(&cache->stats.write_miss),
+ (unsigned) atomic_read(&cache->stats.demotion),
+ (unsigned) atomic_read(&cache->stats.promotion),
+ (unsigned long long) from_cblock(residency),
+ cache->nr_dirty);
+
+ if (cache->features.write_through)
+ DMEMIT("1 writethrough ");
+ else
+ DMEMIT("0 ");
+
+ DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold);
+ if (sz < maxlen) {
+ r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz);
+ if (r)
+ DMERR("policy_emit_config_values returned %d", r);
+ }
+
+ break;
+
+ case STATUSTYPE_TABLE:
+ format_dev_t(buf, cache->metadata_dev->bdev->bd_dev);
+ DMEMIT("%s ", buf);
+ format_dev_t(buf, cache->cache_dev->bdev->bd_dev);
+ DMEMIT("%s ", buf);
+ format_dev_t(buf, cache->origin_dev->bdev->bd_dev);
+ DMEMIT("%s", buf);
+
+ for (i = 0; i < cache->nr_ctr_args - 1; i++)
+ DMEMIT(" %s", cache->ctr_args[i]);
+ if (cache->nr_ctr_args)
+ DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]);
+ }
+
+ return;
+
+err:
+ DMEMIT("Error");
+}
+
+#define NOT_CORE_OPTION 1
+
+static int process_config_option(struct cache *cache, char **argv)
+{
+ unsigned long tmp;
+
+ if (!strcasecmp(argv[0], "migration_threshold")) {
+ if (kstrtoul(argv[1], 10, &tmp))
+ return -EINVAL;
+
+ cache->migration_threshold = tmp;
+ return 0;
+ }
+
+ return NOT_CORE_OPTION;
+}
+
+/*
+ * Supports <key> <value>.
+ *
+ * The key migration_threshold is supported by the cache target core.
+ */
+static int cache_message(struct dm_target *ti, unsigned argc, char **argv)
+{
+ int r;
+ struct cache *cache = ti->private;
+
+ if (argc != 2)
+ return -EINVAL;
+
+ r = process_config_option(cache, argv);
+ if (r == NOT_CORE_OPTION)
+ return policy_set_config_value(cache->policy, argv[0], argv[1]);
+
+ return r;
+}
+
+static int cache_iterate_devices(struct dm_target *ti,
+ iterate_devices_callout_fn fn, void *data)
+{
+ int r = 0;
+ struct cache *cache = ti->private;
+
+ r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data);
+ if (!r)
+ r = fn(ti, cache->origin_dev, 0, ti->len, data);
+
+ return r;
+}
+
+/*
+ * We assume I/O is going to the origin (which is the volume
+ * more likely to have restrictions e.g. by being striped).
+ * (Looking up the exact location of the data would be expensive
+ * and could always be out of date by the time the bio is submitted.)
+ */
+static int cache_bvec_merge(struct dm_target *ti,
+ struct bvec_merge_data *bvm,
+ struct bio_vec *biovec, int max_size)
+{
+ struct cache *cache = ti->private;
+ struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev);
+
+ if (!q->merge_bvec_fn)
+ return max_size;
+
+ bvm->bi_bdev = cache->origin_dev->bdev;
+ return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
+}
+
+static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
+{
+ /*
+ * FIXME: these limits may be incompatible with the cache device
+ */
+ limits->max_discard_sectors = cache->discard_block_size * 1024;
+ limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT;
+}
+
+static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
+{
+ struct cache *cache = ti->private;
+
+ blk_limits_io_min(limits, 0);
+ blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT);
+ set_discard_limits(cache, limits);
+}
+
+/*----------------------------------------------------------------*/
+
+static struct target_type cache_target = {
+ .name = "cache",
+ .version = {1, 0, 0},
+ .module = THIS_MODULE,
+ .ctr = cache_ctr,
+ .dtr = cache_dtr,
+ .map = cache_map,
+ .end_io = cache_end_io,
+ .postsuspend = cache_postsuspend,
+ .preresume = cache_preresume,
+ .resume = cache_resume,
+ .status = cache_status,
+ .message = cache_message,
+ .iterate_devices = cache_iterate_devices,
+ .merge = cache_bvec_merge,
+ .io_hints = cache_io_hints,
+};
+
+static int __init dm_cache_init(void)
+{
+ int r;
+
+ r = dm_register_target(&cache_target);
+ if (r) {
+ DMERR("cache target registration failed: %d", r);
+ return r;
+ }
+
+ migration_cache = KMEM_CACHE(dm_cache_migration, 0);
+ if (!migration_cache) {
+ dm_unregister_target(&cache_target);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void __exit dm_cache_exit(void)
+{
+ dm_unregister_target(&cache_target);
+ kmem_cache_destroy(migration_cache);
+}
+
+module_init(dm_cache_init);
+module_exit(dm_cache_exit);
+
+MODULE_DESCRIPTION(DM_NAME " cache target");
+MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index f7369f9..13c1548 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1234,20 +1234,6 @@ static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
return 0;
}
-/*
- * Encode key into its hex representation
- */
-static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
-{
- unsigned int i;
-
- for (i = 0; i < size; i++) {
- sprintf(hex, "%02x", *key);
- hex += 2;
- key++;
- }
-}
-
static void crypt_free_tfms(struct crypt_config *cc)
{
unsigned i;
@@ -1651,7 +1637,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
if (opt_params == 1 && opt_string &&
!strcasecmp(opt_string, "allow_discards"))
- ti->num_discard_requests = 1;
+ ti->num_discard_bios = 1;
else if (opt_params) {
ret = -EINVAL;
ti->error = "Invalid feature arguments";
@@ -1679,7 +1665,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad;
}
- ti->num_flush_requests = 1;
+ ti->num_flush_bios = 1;
ti->discard_zeroes_data_unsupported = true;
return 0;
@@ -1717,11 +1703,11 @@ static int crypt_map(struct dm_target *ti, struct bio *bio)
return DM_MAPIO_SUBMITTED;
}
-static int crypt_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void crypt_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
struct crypt_config *cc = ti->private;
- unsigned int sz = 0;
+ unsigned i, sz = 0;
switch (type) {
case STATUSTYPE_INFO:
@@ -1731,27 +1717,20 @@ static int crypt_status(struct dm_target *ti, status_type_t type,
case STATUSTYPE_TABLE:
DMEMIT("%s ", cc->cipher_string);
- if (cc->key_size > 0) {
- if ((maxlen - sz) < ((cc->key_size << 1) + 1))
- return -ENOMEM;
-
- crypt_encode_key(result + sz, cc->key, cc->key_size);
- sz += cc->key_size << 1;
- } else {
- if (sz >= maxlen)
- return -ENOMEM;
- result[sz++] = '-';
- }
+ if (cc->key_size > 0)
+ for (i = 0; i < cc->key_size; i++)
+ DMEMIT("%02x", cc->key[i]);
+ else
+ DMEMIT("-");
DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
cc->dev->name, (unsigned long long)cc->start);
- if (ti->num_discard_requests)
+ if (ti->num_discard_bios)
DMEMIT(" 1 allow_discards");
break;
}
- return 0;
}
static void crypt_postsuspend(struct dm_target *ti)
@@ -1845,7 +1824,7 @@ static int crypt_iterate_devices(struct dm_target *ti,
static struct target_type crypt_target = {
.name = "crypt",
- .version = {1, 12, 0},
+ .version = {1, 12, 1},
.module = THIS_MODULE,
.ctr = crypt_ctr,
.dtr = crypt_dtr,
diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index cc1bd04..496d5f3 100644
--- a/drivers/md/dm-delay.c
+++ b/drivers/md/dm-delay.c
@@ -198,8 +198,8 @@ out:
mutex_init(&dc->timer_lock);
atomic_set(&dc->may_delay, 1);
- ti->num_flush_requests = 1;
- ti->num_discard_requests = 1;
+ ti->num_flush_bios = 1;
+ ti->num_discard_bios = 1;
ti->private = dc;
return 0;
@@ -293,8 +293,8 @@ static int delay_map(struct dm_target *ti, struct bio *bio)
return delay_bio(dc, dc->read_delay, bio);
}
-static int delay_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void delay_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
struct delay_c *dc = ti->private;
int sz = 0;
@@ -314,8 +314,6 @@ static int delay_status(struct dm_target *ti, status_type_t type,
dc->write_delay);
break;
}
-
- return 0;
}
static int delay_iterate_devices(struct dm_target *ti,
@@ -337,7 +335,7 @@ out:
static struct target_type delay_target = {
.name = "delay",
- .version = {1, 2, 0},
+ .version = {1, 2, 1},
.module = THIS_MODULE,
.ctr = delay_ctr,
.dtr = delay_dtr,
diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index 9721f2f..7fcf21c 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -216,8 +216,8 @@ static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad;
}
- ti->num_flush_requests = 1;
- ti->num_discard_requests = 1;
+ ti->num_flush_bios = 1;
+ ti->num_discard_bios = 1;
ti->per_bio_data_size = sizeof(struct per_bio_data);
ti->private = fc;
return 0;
@@ -337,8 +337,8 @@ static int flakey_end_io(struct dm_target *ti, struct bio *bio, int error)
return error;
}
-static int flakey_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void flakey_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
unsigned sz = 0;
struct flakey_c *fc = ti->private;
@@ -368,7 +368,6 @@ static int flakey_status(struct dm_target *ti, status_type_t type,
break;
}
- return 0;
}
static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long arg)
@@ -411,7 +410,7 @@ static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_
static struct target_type flakey_target = {
.name = "flakey",
- .version = {1, 3, 0},
+ .version = {1, 3, 1},
.module = THIS_MODULE,
.ctr = flakey_ctr,
.dtr = flakey_dtr,
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 0666b5d..aa04f02 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1067,6 +1067,7 @@ static void retrieve_status(struct dm_table *table,
num_targets = dm_table_get_num_targets(table);
for (i = 0; i < num_targets; i++) {
struct dm_target *ti = dm_table_get_target(table, i);
+ size_t l;
remaining = len - (outptr - outbuf);
if (remaining <= sizeof(struct dm_target_spec)) {
@@ -1093,14 +1094,17 @@ static void retrieve_status(struct dm_table *table,
if (ti->type->status) {
if (param->flags & DM_NOFLUSH_FLAG)
status_flags |= DM_STATUS_NOFLUSH_FLAG;
- if (ti->type->status(ti, type, status_flags, outptr, remaining)) {
- param->flags |= DM_BUFFER_FULL_FLAG;
- break;
- }
+ ti->type->status(ti, type, status_flags, outptr, remaining);
} else
outptr[0] = '\0';
- outptr += strlen(outptr) + 1;
+ l = strlen(outptr) + 1;
+ if (l == remaining) {
+ param->flags |= DM_BUFFER_FULL_FLAG;
+ break;
+ }
+
+ outptr += l;
used = param->data_start + (outptr - outbuf);
outptr = align_ptr(outptr);
@@ -1410,6 +1414,22 @@ static int table_status(struct dm_ioctl *param, size_t param_size)
return 0;
}
+static bool buffer_test_overflow(char *result, unsigned maxlen)
+{
+ return !maxlen || strlen(result) + 1 >= maxlen;
+}
+
+/*
+ * Process device-mapper dependent messages.
+ * Returns a number <= 1 if message was processed by device mapper.
+ * Returns 2 if message should be delivered to the target.
+ */
+static int message_for_md(struct mapped_device *md, unsigned argc, char **argv,
+ char *result, unsigned maxlen)
+{
+ return 2;
+}
+
/*
* Pass a message to the target that's at the supplied device offset.
*/
@@ -1421,6 +1441,8 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
struct dm_table *table;
struct dm_target *ti;
struct dm_target_msg *tmsg = (void *) param + param->data_start;
+ size_t maxlen;
+ char *result = get_result_buffer(param, param_size, &maxlen);
md = find_device(param);
if (!md)
@@ -1444,6 +1466,10 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
goto out_argv;
}
+ r = message_for_md(md, argc, argv, result, maxlen);
+ if (r <= 1)
+ goto out_argv;
+
table = dm_get_live_table(md);
if (!table)
goto out_argv;
@@ -1469,44 +1495,68 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
out_argv:
kfree(argv);
out:
- param->data_size = 0;
+ if (r >= 0)
+ __dev_status(md, param);
+
+ if (r == 1) {
+ param->flags |= DM_DATA_OUT_FLAG;
+ if (buffer_test_overflow(result, maxlen))
+ param->flags |= DM_BUFFER_FULL_FLAG;
+ else
+ param->data_size = param->data_start + strlen(result) + 1;
+ r = 0;
+ }
+
dm_put(md);
return r;
}
+/*
+ * The ioctl parameter block consists of two parts, a dm_ioctl struct
+ * followed by a data buffer. This flag is set if the second part,
+ * which has a variable size, is not used by the function processing
+ * the ioctl.
+ */
+#define IOCTL_FLAGS_NO_PARAMS 1
+
/*-----------------------------------------------------------------
* Implementation of open/close/ioctl on the special char
* device.
*---------------------------------------------------------------*/
-static ioctl_fn lookup_ioctl(unsigned int cmd)
+static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags)
{
static struct {
int cmd;
+ int flags;
ioctl_fn fn;
} _ioctls[] = {
- {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
- {DM_REMOVE_ALL_CMD, remove_all},
- {DM_LIST_DEVICES_CMD, list_devices},
-
- {DM_DEV_CREATE_CMD, dev_create},
- {DM_DEV_REMOVE_CMD, dev_remove},
- {DM_DEV_RENAME_CMD, dev_rename},
- {DM_DEV_SUSPEND_CMD, dev_suspend},
- {DM_DEV_STATUS_CMD, dev_status},
- {DM_DEV_WAIT_CMD, dev_wait},
-
- {DM_TABLE_LOAD_CMD, table_load},
- {DM_TABLE_CLEAR_CMD, table_clear},
- {DM_TABLE_DEPS_CMD, table_deps},
- {DM_TABLE_STATUS_CMD, table_status},
-
- {DM_LIST_VERSIONS_CMD, list_versions},
-
- {DM_TARGET_MSG_CMD, target_message},
- {DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry}
+ {DM_VERSION_CMD, 0, NULL}, /* version is dealt with elsewhere */
+ {DM_REMOVE_ALL_CMD, IOCTL_FLAGS_NO_PARAMS, remove_all},
+ {DM_LIST_DEVICES_CMD, 0, list_devices},
+
+ {DM_DEV_CREATE_CMD, IOCTL_FLAGS_NO_PARAMS, dev_create},
+ {DM_DEV_REMOVE_CMD, IOCTL_FLAGS_NO_PARAMS, dev_remove},
+ {DM_DEV_RENAME_CMD, 0, dev_rename},
+ {DM_DEV_SUSPEND_CMD, IOCTL_FLAGS_NO_PARAMS, dev_suspend},
+ {DM_DEV_STATUS_CMD, IOCTL_FLAGS_NO_PARAMS, dev_status},
+ {DM_DEV_WAIT_CMD, 0, dev_wait},
+
+ {DM_TABLE_LOAD_CMD, 0, table_load},
+ {DM_TABLE_CLEAR_CMD, IOCTL_FLAGS_NO_PARAMS, table_clear},
+ {DM_TABLE_DEPS_CMD, 0, table_deps},
+ {DM_TABLE_STATUS_CMD, 0, table_status},
+
+ {DM_LIST_VERSIONS_CMD, 0, list_versions},
+
+ {DM_TARGET_MSG_CMD, 0, target_message},
+ {DM_DEV_SET_GEOMETRY_CMD, 0, dev_set_geometry}
};
- return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
+ if (unlikely(cmd >= ARRAY_SIZE(_ioctls)))
+ return NULL;
+
+ *ioctl_flags = _ioctls[cmd].flags;
+ return _ioctls[cmd].fn;
}
/*
@@ -1543,7 +1593,8 @@ static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
return r;
}
-#define DM_PARAMS_VMALLOC 0x0001 /* Params alloced with vmalloc not kmalloc */
+#define DM_PARAMS_KMALLOC 0x0001 /* Params alloced with kmalloc */
+#define DM_PARAMS_VMALLOC 0x0002 /* Params alloced with vmalloc */
#define DM_WIPE_BUFFER 0x0010 /* Wipe input buffer before returning from ioctl */
static void free_params(struct dm_ioctl *param, size_t param_size, int param_flags)
@@ -1551,66 +1602,80 @@ static void free_params(struct dm_ioctl *param, size_t param_size, int param_fla
if (param_flags & DM_WIPE_BUFFER)
memset(param, 0, param_size);
+ if (param_flags & DM_PARAMS_KMALLOC)
+ kfree(param);
if (param_flags & DM_PARAMS_VMALLOC)
vfree(param);
- else
- kfree(param);
}
-static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param, int *param_flags)
+static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kernel,
+ int ioctl_flags,
+ struct dm_ioctl **param, int *param_flags)
{
- struct dm_ioctl tmp, *dmi;
+ struct dm_ioctl *dmi;
int secure_data;
+ const size_t minimum_data_size = sizeof(*param_kernel) - sizeof(param_kernel->data);
- if (copy_from_user(&tmp, user, sizeof(tmp) - sizeof(tmp.data)))
+ if (copy_from_user(param_kernel, user, minimum_data_size))
return -EFAULT;
- if (tmp.data_size < (sizeof(tmp) - sizeof(tmp.data)))
+ if (param_kernel->data_size < minimum_data_size)
return -EINVAL;
- secure_data = tmp.flags & DM_SECURE_DATA_FLAG;
+ secure_data = param_kernel->flags & DM_SECURE_DATA_FLAG;
*param_flags = secure_data ? DM_WIPE_BUFFER : 0;
+ if (ioctl_flags & IOCTL_FLAGS_NO_PARAMS) {
+ dmi = param_kernel;
+ dmi->data_size = minimum_data_size;
+ goto data_copied;
+ }
+
/*
* Try to avoid low memory issues when a device is suspended.
* Use kmalloc() rather than vmalloc() when we can.
*/
dmi = NULL;
- if (tmp.data_size <= KMALLOC_MAX_SIZE)
- dmi = kmalloc(tmp.data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
+ if (param_kernel->data_size <= KMALLOC_MAX_SIZE) {
+ dmi = kmalloc(param_kernel->data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
+ if (dmi)
+ *param_flags |= DM_PARAMS_KMALLOC;
+ }
if (!dmi) {
- dmi = __vmalloc(tmp.data_size, GFP_NOIO | __GFP_REPEAT | __GFP_HIGH, PAGE_KERNEL);
- *param_flags |= DM_PARAMS_VMALLOC;
+ dmi = __vmalloc(param_kernel->data_size, GFP_NOIO | __GFP_REPEAT | __GFP_HIGH, PAGE_KERNEL);
+ if (dmi)
+ *param_flags |= DM_PARAMS_VMALLOC;
}
if (!dmi) {
- if (secure_data && clear_user(user, tmp.data_size))
+ if (secure_data && clear_user(user, param_kernel->data_size))
return -EFAULT;
return -ENOMEM;
}
- if (copy_from_user(dmi, user, tmp.data_size))
+ if (copy_from_user(dmi, user, param_kernel->data_size))
goto bad;
+data_copied:
/*
* Abort if something changed the ioctl data while it was being copied.
*/
- if (dmi->data_size != tmp.data_size) {
+ if (dmi->data_size != param_kernel->data_size) {
DMERR("rejecting ioctl: data size modified while processing parameters");
goto bad;
}
/* Wipe the user buffer so we do not return it to userspace */
- if (secure_data && clear_user(user, tmp.data_size))
+ if (secure_data && clear_user(user, param_kernel->data_size))
goto bad;
*param = dmi;
return 0;
bad:
- free_params(dmi, tmp.data_size, *param_flags);
+ free_params(dmi, param_kernel->data_size, *param_flags);
return -EFAULT;
}
@@ -1621,6 +1686,7 @@ static int validate_params(uint cmd, struct dm_ioctl *param)
param->flags &= ~DM_BUFFER_FULL_FLAG;
param->flags &= ~DM_UEVENT_GENERATED_FLAG;
param->flags &= ~DM_SECURE_DATA_FLAG;
+ param->flags &= ~DM_DATA_OUT_FLAG;
/* Ignores parameters */
if (cmd == DM_REMOVE_ALL_CMD ||
@@ -1648,11 +1714,13 @@ static int validate_params(uint cmd, struct dm_ioctl *param)
static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
{
int r = 0;
+ int ioctl_flags;
int param_flags;
unsigned int cmd;
struct dm_ioctl *uninitialized_var(param);
ioctl_fn fn = NULL;
size_t input_param_size;
+ struct dm_ioctl param_kernel;
/* only root can play with this */
if (!capable(CAP_SYS_ADMIN))
@@ -1677,7 +1745,7 @@ static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
if (cmd == DM_VERSION_CMD)
return 0;
- fn = lookup_ioctl(cmd);
+ fn = lookup_ioctl(cmd, &ioctl_flags);
if (!fn) {
DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
return -ENOTTY;
@@ -1686,7 +1754,7 @@ static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
/*
* Copy the parameters into kernel space.
*/
- r = copy_params(user, &param, &param_flags);
+ r = copy_params(user, &param_kernel, ioctl_flags, &param, &param_flags);
if (r)
return r;
@@ -1699,6 +1767,10 @@ static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
param->data_size = sizeof(*param);
r = fn(param, input_param_size);
+ if (unlikely(param->flags & DM_BUFFER_FULL_FLAG) &&
+ unlikely(ioctl_flags & IOCTL_FLAGS_NO_PARAMS))
+ DMERR("ioctl %d tried to output some data but has IOCTL_FLAGS_NO_PARAMS set", cmd);
+
/*
* Copy the results back to userland.
*/
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index 68c0267..d581fe5 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -22,6 +22,7 @@
#include <linux/vmalloc.h>
#include <linux/workqueue.h>
#include <linux/mutex.h>
+#include <linux/delay.h>
#include <linux/device-mapper.h>
#include <linux/dm-kcopyd.h>
@@ -51,6 +52,8 @@ struct dm_kcopyd_client {
struct workqueue_struct *kcopyd_wq;
struct work_struct kcopyd_work;
+ struct dm_kcopyd_throttle *throttle;
+
/*
* We maintain three lists of jobs:
*
@@ -68,6 +71,117 @@ struct dm_kcopyd_client {
static struct page_list zero_page_list;
+static DEFINE_SPINLOCK(throttle_spinlock);
+
+/*
+ * IO/IDLE accounting slowly decays after (1 << ACCOUNT_INTERVAL_SHIFT) period.
+ * When total_period >= (1 << ACCOUNT_INTERVAL_SHIFT) the counters are divided
+ * by 2.
+ */
+#define ACCOUNT_INTERVAL_SHIFT SHIFT_HZ
+
+/*
+ * Sleep this number of milliseconds.
+ *
+ * The value was decided experimentally.
+ * Smaller values seem to cause an increased copy rate above the limit.
+ * The reason for this is unknown but possibly due to jiffies rounding errors
+ * or read/write cache inside the disk.
+ */
+#define SLEEP_MSEC 100
+
+/*
+ * Maximum number of sleep events. There is a theoretical livelock if more
+ * kcopyd clients do work simultaneously which this limit avoids.
+ */
+#define MAX_SLEEPS 10
+
+static void io_job_start(struct dm_kcopyd_throttle *t)
+{
+ unsigned throttle, now, difference;
+ int slept = 0, skew;
+
+ if (unlikely(!t))
+ return;
+
+try_again:
+ spin_lock_irq(&throttle_spinlock);
+
+ throttle = ACCESS_ONCE(t->throttle);
+
+ if (likely(throttle >= 100))
+ goto skip_limit;
+
+ now = jiffies;
+ difference = now - t->last_jiffies;
+ t->last_jiffies = now;
+ if (t->num_io_jobs)
+ t->io_period += difference;
+ t->total_period += difference;
+
+ /*
+ * Maintain sane values if we got a temporary overflow.
+ */
+ if (unlikely(t->io_period > t->total_period))
+ t->io_period = t->total_period;
+
+ if (unlikely(t->total_period >= (1 << ACCOUNT_INTERVAL_SHIFT))) {
+ int shift = fls(t->total_period >> ACCOUNT_INTERVAL_SHIFT);
+ t->total_period >>= shift;
+ t->io_period >>= shift;
+ }
+
+ skew = t->io_period - throttle * t->total_period / 100;
+
+ if (unlikely(skew > 0) && slept < MAX_SLEEPS) {
+ slept++;
+ spin_unlock_irq(&throttle_spinlock);
+ msleep(SLEEP_MSEC);
+ goto try_again;
+ }
+
+skip_limit:
+ t->num_io_jobs++;
+
+ spin_unlock_irq(&throttle_spinlock);
+}
+
+static void io_job_finish(struct dm_kcopyd_throttle *t)
+{
+ unsigned long flags;
+
+ if (unlikely(!t))
+ return;
+
+ spin_lock_irqsave(&throttle_spinlock, flags);
+
+ t->num_io_jobs--;
+
+ if (likely(ACCESS_ONCE(t->throttle) >= 100))
+ goto skip_limit;
+
+ if (!t->num_io_jobs) {
+ unsigned now, difference;
+
+ now = jiffies;
+ difference = now - t->last_jiffies;
+ t->last_jiffies = now;
+
+ t->io_period += difference;
+ t->total_period += difference;
+
+ /*
+ * Maintain sane values if we got a temporary overflow.
+ */
+ if (unlikely(t->io_period > t->total_period))
+ t->io_period = t->total_period;
+ }
+
+skip_limit:
+ spin_unlock_irqrestore(&throttle_spinlock, flags);
+}
+
+
static void wake(struct dm_kcopyd_client *kc)
{
queue_work(kc->kcopyd_wq, &kc->kcopyd_work);
@@ -348,6 +462,8 @@ static void complete_io(unsigned long error, void *context)
struct kcopyd_job *job = (struct kcopyd_job *) context;
struct dm_kcopyd_client *kc = job->kc;
+ io_job_finish(kc->throttle);
+
if (error) {
if (job->rw & WRITE)
job->write_err |= error;
@@ -389,6 +505,8 @@ static int run_io_job(struct kcopyd_job *job)
.client = job->kc->io_client,
};
+ io_job_start(job->kc->throttle);
+
if (job->rw == READ)
r = dm_io(&io_req, 1, &job->source, NULL);
else
@@ -695,7 +813,7 @@ int kcopyd_cancel(struct kcopyd_job *job, int block)
/*-----------------------------------------------------------------
* Client setup
*---------------------------------------------------------------*/
-struct dm_kcopyd_client *dm_kcopyd_client_create(void)
+struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle)
{
int r = -ENOMEM;
struct dm_kcopyd_client *kc;
@@ -708,6 +826,7 @@ struct dm_kcopyd_client *dm_kcopyd_client_create(void)
INIT_LIST_HEAD(&kc->complete_jobs);
INIT_LIST_HEAD(&kc->io_jobs);
INIT_LIST_HEAD(&kc->pages_jobs);
+ kc->throttle = throttle;
kc->job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache);
if (!kc->job_pool)
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 328cad5..4f99d26 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -53,9 +53,9 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad;
}
- ti->num_flush_requests = 1;
- ti->num_discard_requests = 1;
- ti->num_write_same_requests = 1;
+ ti->num_flush_bios = 1;
+ ti->num_discard_bios = 1;
+ ti->num_write_same_bios = 1;
ti->private = lc;
return 0;
@@ -95,8 +95,8 @@ static int linear_map(struct dm_target *ti, struct bio *bio)
return DM_MAPIO_REMAPPED;
}
-static int linear_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void linear_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
struct linear_c *lc = (struct linear_c *) ti->private;
@@ -110,7 +110,6 @@ static int linear_status(struct dm_target *ti, status_type_t type,
(unsigned long long)lc->start);
break;
}
- return 0;
}
static int linear_ioctl(struct dm_target *ti, unsigned int cmd,
@@ -155,7 +154,7 @@ static int linear_iterate_devices(struct dm_target *ti,
static struct target_type linear_target = {
.name = "linear",
- .version = {1, 2, 0},
+ .version = {1, 2, 1},
.module = THIS_MODULE,
.ctr = linear_ctr,
.dtr = linear_dtr,
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 573bd04..51bb816 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -905,8 +905,8 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
goto bad;
}
- ti->num_flush_requests = 1;
- ti->num_discard_requests = 1;
+ ti->num_flush_bios = 1;
+ ti->num_discard_bios = 1;
return 0;
@@ -1378,8 +1378,8 @@ static void multipath_resume(struct dm_target *ti)
* [priority selector-name num_ps_args [ps_args]*
* num_paths num_selector_args [path_dev [selector_args]* ]+ ]+
*/
-static int multipath_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void multipath_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
int sz = 0;
unsigned long flags;
@@ -1485,8 +1485,6 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
}
spin_unlock_irqrestore(&m->lock, flags);
-
- return 0;
}
static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
@@ -1695,7 +1693,7 @@ out:
*---------------------------------------------------------------*/
static struct target_type multipath_target = {
.name = "multipath",
- .version = {1, 5, 0},
+ .version = {1, 5, 1},
.module = THIS_MODULE,
.ctr = multipath_ctr,
.dtr = multipath_dtr,
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 9e58dbd..9a01d1e 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -1151,7 +1151,7 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
INIT_WORK(&rs->md.event_work, do_table_event);
ti->private = rs;
- ti->num_flush_requests = 1;
+ ti->num_flush_bios = 1;
mutex_lock(&rs->md.reconfig_mutex);
ret = md_run(&rs->md);
@@ -1201,8 +1201,8 @@ static int raid_map(struct dm_target *ti, struct bio *bio)
return DM_MAPIO_SUBMITTED;
}
-static int raid_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void raid_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
struct raid_set *rs = ti->private;
unsigned raid_param_cnt = 1; /* at least 1 for chunksize */
@@ -1344,8 +1344,6 @@ static int raid_status(struct dm_target *ti, status_type_t type,
DMEMIT(" -");
}
}
-
- return 0;
}
static int raid_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
@@ -1405,7 +1403,7 @@ static void raid_resume(struct dm_target *ti)
static struct target_type raid_target = {
.name = "raid",
- .version = {1, 4, 1},
+ .version = {1, 4, 2},
.module = THIS_MODULE,
.ctr = raid_ctr,
.dtr = raid_dtr,
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index fa51918..d053098 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -82,6 +82,9 @@ struct mirror_set {
struct mirror mirror[0];
};
+DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(raid1_resync_throttle,
+ "A percentage of time allocated for raid resynchronization");
+
static void wakeup_mirrord(void *context)
{
struct mirror_set *ms = context;
@@ -1072,8 +1075,8 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
if (r)
goto err_free_context;
- ti->num_flush_requests = 1;
- ti->num_discard_requests = 1;
+ ti->num_flush_bios = 1;
+ ti->num_discard_bios = 1;
ti->per_bio_data_size = sizeof(struct dm_raid1_bio_record);
ti->discard_zeroes_data_unsupported = true;
@@ -1111,7 +1114,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto err_destroy_wq;
}
- ms->kcopyd_client = dm_kcopyd_client_create();
+ ms->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle);
if (IS_ERR(ms->kcopyd_client)) {
r = PTR_ERR(ms->kcopyd_client);
goto err_destroy_wq;
@@ -1347,8 +1350,8 @@ static char device_status_char(struct mirror *m)
}
-static int mirror_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void mirror_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
unsigned int m, sz = 0;
struct mirror_set *ms = (struct mirror_set *) ti->private;
@@ -1383,8 +1386,6 @@ static int mirror_status(struct dm_target *ti, status_type_t type,
if (ms->features & DM_RAID1_HANDLE_ERRORS)
DMEMIT(" 1 handle_errors");
}
-
- return 0;
}
static int mirror_iterate_devices(struct dm_target *ti,
@@ -1403,7 +1404,7 @@ static int mirror_iterate_devices(struct dm_target *ti,
static struct target_type mirror_target = {
.name = "mirror",
- .version = {1, 13, 1},
+ .version = {1, 13, 2},
.module = THIS_MODULE,
.ctr = mirror_ctr,
.dtr = mirror_dtr,
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 10079e0..c0e0702 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -124,6 +124,9 @@ struct dm_snapshot {
#define RUNNING_MERGE 0
#define SHUTDOWN_MERGE 1
+DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
+ "A percentage of time allocated for copy on write");
+
struct dm_dev *dm_snap_origin(struct dm_snapshot *s)
{
return s->origin;
@@ -1037,7 +1040,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
int i;
int r = -EINVAL;
char *origin_path, *cow_path;
- unsigned args_used, num_flush_requests = 1;
+ unsigned args_used, num_flush_bios = 1;
fmode_t origin_mode = FMODE_READ;
if (argc != 4) {
@@ -1047,7 +1050,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
}
if (dm_target_is_snapshot_merge(ti)) {
- num_flush_requests = 2;
+ num_flush_bios = 2;
origin_mode = FMODE_WRITE;
}
@@ -1108,7 +1111,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad_hash_tables;
}
- s->kcopyd_client = dm_kcopyd_client_create();
+ s->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle);
if (IS_ERR(s->kcopyd_client)) {
r = PTR_ERR(s->kcopyd_client);
ti->error = "Could not create kcopyd client";
@@ -1127,7 +1130,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
spin_lock_init(&s->tracked_chunk_lock);
ti->private = s;
- ti->num_flush_requests = num_flush_requests;
+ ti->num_flush_bios = num_flush_bios;
ti->per_bio_data_size = sizeof(struct dm_snap_tracked_chunk);
/* Add snapshot to the list of snapshots for this origin */
@@ -1691,7 +1694,7 @@ static int snapshot_merge_map(struct dm_target *ti, struct bio *bio)
init_tracked_chunk(bio);
if (bio->bi_rw & REQ_FLUSH) {
- if (!dm_bio_get_target_request_nr(bio))
+ if (!dm_bio_get_target_bio_nr(bio))
bio->bi_bdev = s->origin->bdev;
else
bio->bi_bdev = s->cow->bdev;
@@ -1836,8 +1839,8 @@ static void snapshot_merge_resume(struct dm_target *ti)
start_merge(s);
}
-static int snapshot_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void snapshot_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
unsigned sz = 0;
struct dm_snapshot *snap = ti->private;
@@ -1883,8 +1886,6 @@ static int snapshot_status(struct dm_target *ti, status_type_t type,
maxlen - sz);
break;
}
-
- return 0;
}
static int snapshot_iterate_devices(struct dm_target *ti,
@@ -2104,7 +2105,7 @@ static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv)
}
ti->private = dev;
- ti->num_flush_requests = 1;
+ ti->num_flush_bios = 1;
return 0;
}
@@ -2138,8 +2139,8 @@ static void origin_resume(struct dm_target *ti)
ti->max_io_len = get_origin_minimum_chunksize(dev->bdev);
}
-static int origin_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void origin_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
struct dm_dev *dev = ti->private;
@@ -2152,8 +2153,6 @@ static int origin_status(struct dm_target *ti, status_type_t type,
snprintf(result, maxlen, "%s", dev->name);
break;
}
-
- return 0;
}
static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
@@ -2180,7 +2179,7 @@ static int origin_iterate_devices(struct dm_target *ti,
static struct target_type origin_target = {
.name = "snapshot-origin",
- .version = {1, 8, 0},
+ .version = {1, 8, 1},
.module = THIS_MODULE,
.ctr = origin_ctr,
.dtr = origin_dtr,
@@ -2193,7 +2192,7 @@ static struct target_type origin_target = {
static struct target_type snapshot_target = {
.name = "snapshot",
- .version = {1, 11, 0},
+ .version = {1, 11, 1},
.module = THIS_MODULE,
.ctr = snapshot_ctr,
.dtr = snapshot_dtr,
@@ -2306,3 +2305,5 @@ module_exit(dm_snapshot_exit);
MODULE_DESCRIPTION(DM_NAME " snapshot target");
MODULE_AUTHOR("Joe Thornber");
MODULE_LICENSE("GPL");
+MODULE_ALIAS("dm-snapshot-origin");
+MODULE_ALIAS("dm-snapshot-merge");
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index c89cde8..d8837d3 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -160,9 +160,9 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
if (r)
return r;
- ti->num_flush_requests = stripes;
- ti->num_discard_requests = stripes;
- ti->num_write_same_requests = stripes;
+ ti->num_flush_bios = stripes;
+ ti->num_discard_bios = stripes;
+ ti->num_write_same_bios = stripes;
sc->chunk_size = chunk_size;
if (chunk_size & (chunk_size - 1))
@@ -276,19 +276,19 @@ static int stripe_map(struct dm_target *ti, struct bio *bio)
{
struct stripe_c *sc = ti->private;
uint32_t stripe;
- unsigned target_request_nr;
+ unsigned target_bio_nr;
if (bio->bi_rw & REQ_FLUSH) {
- target_request_nr = dm_bio_get_target_request_nr(bio);
- BUG_ON(target_request_nr >= sc->stripes);
- bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
+ target_bio_nr = dm_bio_get_target_bio_nr(bio);
+ BUG_ON(target_bio_nr >= sc->stripes);
+ bio->bi_bdev = sc->stripe[target_bio_nr].dev->bdev;
return DM_MAPIO_REMAPPED;
}
if (unlikely(bio->bi_rw & REQ_DISCARD) ||
unlikely(bio->bi_rw & REQ_WRITE_SAME)) {
- target_request_nr = dm_bio_get_target_request_nr(bio);
- BUG_ON(target_request_nr >= sc->stripes);
- return stripe_map_range(sc, bio, target_request_nr);
+ target_bio_nr = dm_bio_get_target_bio_nr(bio);
+ BUG_ON(target_bio_nr >= sc->stripes);
+ return stripe_map_range(sc, bio, target_bio_nr);
}
stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
@@ -312,8 +312,8 @@ static int stripe_map(struct dm_target *ti, struct bio *bio)
*
*/
-static int stripe_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void stripe_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
struct stripe_c *sc = (struct stripe_c *) ti->private;
char buffer[sc->stripes + 1];
@@ -340,7 +340,6 @@ static int stripe_status(struct dm_target *ti, status_type_t type,
(unsigned long long)sc->stripe[i].physical_start);
break;
}
- return 0;
}
static int stripe_end_io(struct dm_target *ti, struct bio *bio, int error)
@@ -428,7 +427,7 @@ static int stripe_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
static struct target_type stripe_target = {
.name = "striped",
- .version = {1, 5, 0},
+ .version = {1, 5, 1},
.module = THIS_MODULE,
.ctr = stripe_ctr,
.dtr = stripe_dtr,
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index daf25d0..e50dad0 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -217,7 +217,6 @@ int dm_table_create(struct dm_table **result, fmode_t mode,
if (alloc_targets(t, num_targets)) {
kfree(t);
- t = NULL;
return -ENOMEM;
}
@@ -823,8 +822,8 @@ int dm_table_add_target(struct dm_table *t, const char *type,
t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
- if (!tgt->num_discard_requests && tgt->discards_supported)
- DMWARN("%s: %s: ignoring discards_supported because num_discard_requests is zero.",
+ if (!tgt->num_discard_bios && tgt->discards_supported)
+ DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
dm_device_name(t->md), type);
return 0;
@@ -1360,7 +1359,7 @@ static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
while (i < dm_table_get_num_targets(t)) {
ti = dm_table_get_target(t, i++);
- if (!ti->num_flush_requests)
+ if (!ti->num_flush_bios)
continue;
if (ti->flush_supported)
@@ -1439,7 +1438,7 @@ static bool dm_table_supports_write_same(struct dm_table *t)
while (i < dm_table_get_num_targets(t)) {
ti = dm_table_get_target(t, i++);
- if (!ti->num_write_same_requests)
+ if (!ti->num_write_same_bios)
return false;
if (!ti->type->iterate_devices ||
@@ -1657,7 +1656,7 @@ bool dm_table_supports_discards(struct dm_table *t)
while (i < dm_table_get_num_targets(t)) {
ti = dm_table_get_target(t, i++);
- if (!ti->num_discard_requests)
+ if (!ti->num_discard_bios)
continue;
if (ti->discards_supported)
diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c
index 617d21a..37ba5db 100644
--- a/drivers/md/dm-target.c
+++ b/drivers/md/dm-target.c
@@ -116,7 +116,7 @@ static int io_err_ctr(struct dm_target *tt, unsigned int argc, char **args)
/*
* Return error for discards instead of -EOPNOTSUPP
*/
- tt->num_discard_requests = 1;
+ tt->num_discard_bios = 1;
return 0;
}
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 4d6e853..00cee02 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -280,7 +280,7 @@ static void unpack_block_time(uint64_t v, dm_block_t *b, uint32_t *t)
*t = v & ((1 << 24) - 1);
}
-static void data_block_inc(void *context, void *value_le)
+static void data_block_inc(void *context, const void *value_le)
{
struct dm_space_map *sm = context;
__le64 v_le;
@@ -292,7 +292,7 @@ static void data_block_inc(void *context, void *value_le)
dm_sm_inc_block(sm, b);
}
-static void data_block_dec(void *context, void *value_le)
+static void data_block_dec(void *context, const void *value_le)
{
struct dm_space_map *sm = context;
__le64 v_le;
@@ -304,7 +304,7 @@ static void data_block_dec(void *context, void *value_le)
dm_sm_dec_block(sm, b);
}
-static int data_block_equal(void *context, void *value1_le, void *value2_le)
+static int data_block_equal(void *context, const void *value1_le, const void *value2_le)
{
__le64 v1_le, v2_le;
uint64_t b1, b2;
@@ -318,7 +318,7 @@ static int data_block_equal(void *context, void *value1_le, void *value2_le)
return b1 == b2;
}
-static void subtree_inc(void *context, void *value)
+static void subtree_inc(void *context, const void *value)
{
struct dm_btree_info *info = context;
__le64 root_le;
@@ -329,7 +329,7 @@ static void subtree_inc(void *context, void *value)
dm_tm_inc(info->tm, root);
}
-static void subtree_dec(void *context, void *value)
+static void subtree_dec(void *context, const void *value)
{
struct dm_btree_info *info = context;
__le64 root_le;
@@ -341,7 +341,7 @@ static void subtree_dec(void *context, void *value)
DMERR("btree delete failed\n");
}
-static int subtree_equal(void *context, void *value1_le, void *value2_le)
+static int subtree_equal(void *context, const void *value1_le, const void *value2_le)
{
__le64 v1_le, v2_le;
memcpy(&v1_le, value1_le, sizeof(v1_le));
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 5409607..009339d 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -26,6 +26,9 @@
#define PRISON_CELLS 1024
#define COMMIT_PERIOD HZ
+DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
+ "A percentage of time allocated for copy on write");
+
/*
* The block size of the device holding pool data must be
* between 64KB and 1GB.
@@ -227,6 +230,78 @@ struct thin_c {
/*----------------------------------------------------------------*/
/*
+ * wake_worker() is used when new work is queued and when pool_resume is
+ * ready to continue deferred IO processing.
+ */
+static void wake_worker(struct pool *pool)
+{
+ queue_work(pool->wq, &pool->worker);
+}
+
+/*----------------------------------------------------------------*/
+
+static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
+ struct dm_bio_prison_cell **cell_result)
+{
+ int r;
+ struct dm_bio_prison_cell *cell_prealloc;
+
+ /*
+ * Allocate a cell from the prison's mempool.
+ * This might block but it can't fail.
+ */
+ cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
+
+ r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
+ if (r)
+ /*
+ * We reused an old cell; we can get rid of
+ * the new one.
+ */
+ dm_bio_prison_free_cell(pool->prison, cell_prealloc);
+
+ return r;
+}
+
+static void cell_release(struct pool *pool,
+ struct dm_bio_prison_cell *cell,
+ struct bio_list *bios)
+{
+ dm_cell_release(pool->prison, cell, bios);
+ dm_bio_prison_free_cell(pool->prison, cell);
+}
+
+static void cell_release_no_holder(struct pool *pool,
+ struct dm_bio_prison_cell *cell,
+ struct bio_list *bios)
+{
+ dm_cell_release_no_holder(pool->prison, cell, bios);
+ dm_bio_prison_free_cell(pool->prison, cell);
+}
+
+static void cell_defer_no_holder_no_free(struct thin_c *tc,
+ struct dm_bio_prison_cell *cell)
+{
+ struct pool *pool = tc->pool;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ dm_cell_release_no_holder(pool->prison, cell, &pool->deferred_bios);
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ wake_worker(pool);
+}
+
+static void cell_error(struct pool *pool,
+ struct dm_bio_prison_cell *cell)
+{
+ dm_cell_error(pool->prison, cell);
+ dm_bio_prison_free_cell(pool->prison, cell);
+}
+
+/*----------------------------------------------------------------*/
+
+/*
* A global list of pools that uses a struct mapped_device as a key.
*/
static struct dm_thin_pool_table {
@@ -330,14 +405,20 @@ static void requeue_io(struct thin_c *tc)
* target.
*/
+static bool block_size_is_power_of_two(struct pool *pool)
+{
+ return pool->sectors_per_block_shift >= 0;
+}
+
static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
{
+ struct pool *pool = tc->pool;
sector_t block_nr = bio->bi_sector;
- if (tc->pool->sectors_per_block_shift < 0)
- (void) sector_div(block_nr, tc->pool->sectors_per_block);
+ if (block_size_is_power_of_two(pool))
+ block_nr >>= pool->sectors_per_block_shift;
else
- block_nr >>= tc->pool->sectors_per_block_shift;
+ (void) sector_div(block_nr, pool->sectors_per_block);
return block_nr;
}
@@ -348,12 +429,12 @@ static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
sector_t bi_sector = bio->bi_sector;
bio->bi_bdev = tc->pool_dev->bdev;
- if (tc->pool->sectors_per_block_shift < 0)
- bio->bi_sector = (block * pool->sectors_per_block) +
- sector_div(bi_sector, pool->sectors_per_block);
- else
+ if (block_size_is_power_of_two(pool))
bio->bi_sector = (block << pool->sectors_per_block_shift) |
(bi_sector & (pool->sectors_per_block - 1));
+ else
+ bio->bi_sector = (block * pool->sectors_per_block) +
+ sector_div(bi_sector, pool->sectors_per_block);
}
static void remap_to_origin(struct thin_c *tc, struct bio *bio)
@@ -420,15 +501,6 @@ static void remap_and_issue(struct thin_c *tc, struct bio *bio,
issue(tc, bio);
}
-/*
- * wake_worker() is used when new work is queued and when pool_resume is
- * ready to continue deferred IO processing.
- */
-static void wake_worker(struct pool *pool)
-{
- queue_work(pool->wq, &pool->worker);
-}
-
/*----------------------------------------------------------------*/
/*
@@ -515,14 +587,14 @@ static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell)
unsigned long flags;
spin_lock_irqsave(&pool->lock, flags);
- dm_cell_release(cell, &pool->deferred_bios);
+ cell_release(pool, cell, &pool->deferred_bios);
spin_unlock_irqrestore(&tc->pool->lock, flags);
wake_worker(pool);
}
/*
- * Same as cell_defer except it omits the original holder of the cell.
+ * Same as cell_defer above, except it omits the original holder of the cell.
*/
static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
{
@@ -530,7 +602,7 @@ static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *c
unsigned long flags;
spin_lock_irqsave(&pool->lock, flags);
- dm_cell_release_no_holder(cell, &pool->deferred_bios);
+ cell_release_no_holder(pool, cell, &pool->deferred_bios);
spin_unlock_irqrestore(&pool->lock, flags);
wake_worker(pool);
@@ -540,13 +612,15 @@ static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
{
if (m->bio)
m->bio->bi_end_io = m->saved_bi_end_io;
- dm_cell_error(m->cell);
+ cell_error(m->tc->pool, m->cell);
list_del(&m->list);
mempool_free(m, m->tc->pool->mapping_pool);
}
+
static void process_prepared_mapping(struct dm_thin_new_mapping *m)
{
struct thin_c *tc = m->tc;
+ struct pool *pool = tc->pool;
struct bio *bio;
int r;
@@ -555,7 +629,7 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m)
bio->bi_end_io = m->saved_bi_end_io;
if (m->err) {
- dm_cell_error(m->cell);
+ cell_error(pool, m->cell);
goto out;
}
@@ -567,7 +641,7 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m)
r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
if (r) {
DMERR_LIMIT("dm_thin_insert_block() failed");
- dm_cell_error(m->cell);
+ cell_error(pool, m->cell);
goto out;
}
@@ -585,7 +659,7 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m)
out:
list_del(&m->list);
- mempool_free(m, tc->pool->mapping_pool);
+ mempool_free(m, pool->mapping_pool);
}
static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
@@ -736,7 +810,7 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
if (r < 0) {
mempool_free(m, pool->mapping_pool);
DMERR_LIMIT("dm_kcopyd_copy() failed");
- dm_cell_error(cell);
+ cell_error(pool, cell);
}
}
}
@@ -802,7 +876,7 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
if (r < 0) {
mempool_free(m, pool->mapping_pool);
DMERR_LIMIT("dm_kcopyd_zero() failed");
- dm_cell_error(cell);
+ cell_error(pool, cell);
}
}
}
@@ -908,13 +982,13 @@ static void retry_on_resume(struct bio *bio)
spin_unlock_irqrestore(&pool->lock, flags);
}
-static void no_space(struct dm_bio_prison_cell *cell)
+static void no_space(struct pool *pool, struct dm_bio_prison_cell *cell)
{
struct bio *bio;
struct bio_list bios;
bio_list_init(&bios);
- dm_cell_release(cell, &bios);
+ cell_release(pool, cell, &bios);
while ((bio = bio_list_pop(&bios)))
retry_on_resume(bio);
@@ -932,7 +1006,7 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
struct dm_thin_new_mapping *m;
build_virtual_key(tc->td, block, &key);
- if (dm_bio_detain(tc->pool->prison, &key, bio, &cell))
+ if (bio_detain(tc->pool, &key, bio, &cell))
return;
r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
@@ -944,7 +1018,7 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
* on this block.
*/
build_data_key(tc->td, lookup_result.block, &key2);
- if (dm_bio_detain(tc->pool->prison, &key2, bio, &cell2)) {
+ if (bio_detain(tc->pool, &key2, bio, &cell2)) {
cell_defer_no_holder(tc, cell);
break;
}
@@ -1020,13 +1094,13 @@ static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
break;
case -ENOSPC:
- no_space(cell);
+ no_space(tc->pool, cell);
break;
default:
DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
__func__, r);
- dm_cell_error(cell);
+ cell_error(tc->pool, cell);
break;
}
}
@@ -1044,7 +1118,7 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio,
* of being broken so we have nothing further to do here.
*/
build_data_key(tc->td, lookup_result->block, &key);
- if (dm_bio_detain(pool->prison, &key, bio, &cell))
+ if (bio_detain(pool, &key, bio, &cell))
return;
if (bio_data_dir(bio) == WRITE && bio->bi_size)
@@ -1065,12 +1139,13 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block
{
int r;
dm_block_t data_block;
+ struct pool *pool = tc->pool;
/*
* Remap empty bios (flushes) immediately, without provisioning.
*/
if (!bio->bi_size) {
- inc_all_io_entry(tc->pool, bio);
+ inc_all_io_entry(pool, bio);
cell_defer_no_holder(tc, cell);
remap_and_issue(tc, bio, 0);
@@ -1097,14 +1172,14 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block
break;
case -ENOSPC:
- no_space(cell);
+ no_space(pool, cell);
break;
default:
DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
__func__, r);
- set_pool_mode(tc->pool, PM_READ_ONLY);
- dm_cell_error(cell);
+ set_pool_mode(pool, PM_READ_ONLY);
+ cell_error(pool, cell);
break;
}
}
@@ -1112,6 +1187,7 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block
static void process_bio(struct thin_c *tc, struct bio *bio)
{
int r;
+ struct pool *pool = tc->pool;
dm_block_t block = get_bio_block(tc, bio);
struct dm_bio_prison_cell *cell;
struct dm_cell_key key;
@@ -1122,7 +1198,7 @@ static void process_bio(struct thin_c *tc, struct bio *bio)
* being provisioned so we have nothing further to do here.
*/
build_virtual_key(tc->td, block, &key);
- if (dm_bio_detain(tc->pool->prison, &key, bio, &cell))
+ if (bio_detain(pool, &key, bio, &cell))
return;
r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
@@ -1130,9 +1206,9 @@ static void process_bio(struct thin_c *tc, struct bio *bio)
case 0:
if (lookup_result.shared) {
process_shared_bio(tc, bio, block, &lookup_result);
- cell_defer_no_holder(tc, cell);
+ cell_defer_no_holder(tc, cell); /* FIXME: pass this cell into process_shared? */
} else {
- inc_all_io_entry(tc->pool, bio);
+ inc_all_io_entry(pool, bio);
cell_defer_no_holder(tc, cell);
remap_and_issue(tc, bio, lookup_result.block);
@@ -1141,7 +1217,7 @@ static void process_bio(struct thin_c *tc, struct bio *bio)
case -ENODATA:
if (bio_data_dir(bio) == READ && tc->origin_dev) {
- inc_all_io_entry(tc->pool, bio);
+ inc_all_io_entry(pool, bio);
cell_defer_no_holder(tc, cell);
remap_to_origin_and_issue(tc, bio);
@@ -1378,7 +1454,8 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio)
dm_block_t block = get_bio_block(tc, bio);
struct dm_thin_device *td = tc->td;
struct dm_thin_lookup_result result;
- struct dm_bio_prison_cell *cell1, *cell2;
+ struct dm_bio_prison_cell cell1, cell2;
+ struct dm_bio_prison_cell *cell_result;
struct dm_cell_key key;
thin_hook_bio(tc, bio);
@@ -1420,18 +1497,18 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio)
}
build_virtual_key(tc->td, block, &key);
- if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1))
+ if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
return DM_MAPIO_SUBMITTED;
build_data_key(tc->td, result.block, &key);
- if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2)) {
- cell_defer_no_holder(tc, cell1);
+ if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2, &cell_result)) {
+ cell_defer_no_holder_no_free(tc, &cell1);
return DM_MAPIO_SUBMITTED;
}
inc_all_io_entry(tc->pool, bio);
- cell_defer_no_holder(tc, cell2);
- cell_defer_no_holder(tc, cell1);
+ cell_defer_no_holder_no_free(tc, &cell2);
+ cell_defer_no_holder_no_free(tc, &cell1);
remap(tc, bio, result.block);
return DM_MAPIO_REMAPPED;
@@ -1636,7 +1713,7 @@ static struct pool *pool_create(struct mapped_device *pool_md,
goto bad_prison;
}
- pool->copier = dm_kcopyd_client_create();
+ pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
if (IS_ERR(pool->copier)) {
r = PTR_ERR(pool->copier);
*error = "Error creating pool's kcopyd client";
@@ -1938,7 +2015,7 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
pt->data_dev = data_dev;
pt->low_water_blocks = low_water_blocks;
pt->adjusted_pf = pt->requested_pf = pf;
- ti->num_flush_requests = 1;
+ ti->num_flush_bios = 1;
/*
* Only need to enable discards if the pool should pass
@@ -1946,7 +2023,7 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
* processing will cause mappings to be removed from the btree.
*/
if (pf.discard_enabled && pf.discard_passdown) {
- ti->num_discard_requests = 1;
+ ti->num_discard_bios = 1;
/*
* Setting 'discards_supported' circumvents the normal
@@ -2299,8 +2376,8 @@ static void emit_flags(struct pool_features *pf, char *result,
* <transaction id> <used metadata sectors>/<total metadata sectors>
* <used data sectors>/<total data sectors> <held metadata root>
*/
-static int pool_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void pool_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
int r;
unsigned sz = 0;
@@ -2326,32 +2403,41 @@ static int pool_status(struct dm_target *ti, status_type_t type,
if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
(void) commit_or_fallback(pool);
- r = dm_pool_get_metadata_transaction_id(pool->pmd,
- &transaction_id);
- if (r)
- return r;
+ r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
+ if (r) {
+ DMERR("dm_pool_get_metadata_transaction_id returned %d", r);
+ goto err;
+ }
- r = dm_pool_get_free_metadata_block_count(pool->pmd,
- &nr_free_blocks_metadata);
- if (r)
- return r;
+ r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
+ if (r) {
+ DMERR("dm_pool_get_free_metadata_block_count returned %d", r);
+ goto err;
+ }
r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
- if (r)
- return r;
+ if (r) {
+ DMERR("dm_pool_get_metadata_dev_size returned %d", r);
+ goto err;
+ }
- r = dm_pool_get_free_block_count(pool->pmd,
- &nr_free_blocks_data);
- if (r)
- return r;
+ r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
+ if (r) {
+ DMERR("dm_pool_get_free_block_count returned %d", r);
+ goto err;
+ }
r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
- if (r)
- return r;
+ if (r) {
+ DMERR("dm_pool_get_data_dev_size returned %d", r);
+ goto err;
+ }
r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
- if (r)
- return r;
+ if (r) {
+ DMERR("dm_pool_get_metadata_snap returned %d", r);
+ goto err;
+ }
DMEMIT("%llu %llu/%llu %llu/%llu ",
(unsigned long long)transaction_id,
@@ -2388,8 +2474,10 @@ static int pool_status(struct dm_target *ti, status_type_t type,
emit_flags(&pt->requested_pf, result, sz, maxlen);
break;
}
+ return;
- return 0;
+err:
+ DMEMIT("Error");
}
static int pool_iterate_devices(struct dm_target *ti,
@@ -2414,11 +2502,6 @@ static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
}
-static bool block_size_is_power_of_two(struct pool *pool)
-{
- return pool->sectors_per_block_shift >= 0;
-}
-
static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
{
struct pool *pool = pt->pool;
@@ -2432,15 +2515,8 @@ static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
if (pt->adjusted_pf.discard_passdown) {
data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
limits->discard_granularity = data_limits->discard_granularity;
- } else if (block_size_is_power_of_two(pool))
+ } else
limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
- else
- /*
- * Use largest power of 2 that is a factor of sectors_per_block
- * but at least DATA_DEV_BLOCK_SIZE_MIN_SECTORS.
- */
- limits->discard_granularity = max(1 << (ffs(pool->sectors_per_block) - 1),
- DATA_DEV_BLOCK_SIZE_MIN_SECTORS) << SECTOR_SHIFT;
}
static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
@@ -2468,7 +2544,7 @@ static struct target_type pool_target = {
.name = "thin-pool",
.features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
DM_TARGET_IMMUTABLE,
- .version = {1, 6, 0},
+ .version = {1, 6, 1},
.module = THIS_MODULE,
.ctr = pool_ctr,
.dtr = pool_dtr,
@@ -2588,17 +2664,17 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
if (r)
goto bad_thin_open;
- ti->num_flush_requests = 1;
+ ti->num_flush_bios = 1;
ti->flush_supported = true;
ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
/* In case the pool supports discards, pass them on. */
if (tc->pool->pf.discard_enabled) {
ti->discards_supported = true;
- ti->num_discard_requests = 1;
+ ti->num_discard_bios = 1;
ti->discard_zeroes_data_unsupported = true;
- /* Discard requests must be split on a block boundary */
- ti->split_discard_requests = true;
+ /* Discard bios must be split on a block boundary */
+ ti->split_discard_bios = true;
}
dm_put(pool_md);
@@ -2676,8 +2752,8 @@ static void thin_postsuspend(struct dm_target *ti)
/*
* <nr mapped sectors> <highest mapped sector>
*/
-static int thin_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void thin_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
int r;
ssize_t sz = 0;
@@ -2687,7 +2763,7 @@ static int thin_status(struct dm_target *ti, status_type_t type,
if (get_pool_mode(tc->pool) == PM_FAIL) {
DMEMIT("Fail");
- return 0;
+ return;
}
if (!tc->td)
@@ -2696,12 +2772,16 @@ static int thin_status(struct dm_target *ti, status_type_t type,
switch (type) {
case STATUSTYPE_INFO:
r = dm_thin_get_mapped_count(tc->td, &mapped);
- if (r)
- return r;
+ if (r) {
+ DMERR("dm_thin_get_mapped_count returned %d", r);
+ goto err;
+ }
r = dm_thin_get_highest_mapped_block(tc->td, &highest);
- if (r < 0)
- return r;
+ if (r < 0) {
+ DMERR("dm_thin_get_highest_mapped_block returned %d", r);
+ goto err;
+ }
DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
if (r)
@@ -2721,7 +2801,10 @@ static int thin_status(struct dm_target *ti, status_type_t type,
}
}
- return 0;
+ return;
+
+err:
+ DMEMIT("Error");
}
static int thin_iterate_devices(struct dm_target *ti,
@@ -2748,7 +2831,7 @@ static int thin_iterate_devices(struct dm_target *ti,
static struct target_type thin_target = {
.name = "thin",
- .version = {1, 7, 0},
+ .version = {1, 7, 1},
.module = THIS_MODULE,
.ctr = thin_ctr,
.dtr = thin_dtr,
diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity.c
index 52cde982..6ad5383 100644
--- a/drivers/md/dm-verity.c
+++ b/drivers/md/dm-verity.c
@@ -508,8 +508,8 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
/*
* Status: V (valid) or C (corruption found)
*/
-static int verity_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
+static void verity_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
{
struct dm_verity *v = ti->private;
unsigned sz = 0;
@@ -540,8 +540,6 @@ static int verity_status(struct dm_target *ti, status_type_t type,
DMEMIT("%02x", v->salt[x]);
break;
}
-
- return 0;
}
static int verity_ioctl(struct dm_target *ti, unsigned cmd,
@@ -860,7 +858,7 @@ bad:
static struct target_type verity_target = {
.name = "verity",
- .version = {1, 1, 0},
+ .version = {1, 1, 1},
.module = THIS_MODULE,
.ctr = verity_ctr,
.dtr = verity_dtr,
diff --git a/drivers/md/dm-zero.c b/drivers/md/dm-zero.c
index 69a5c3b..c99003e 100644
--- a/drivers/md/dm-zero.c
+++ b/drivers/md/dm-zero.c
@@ -25,7 +25,7 @@ static int zero_ctr(struct dm_target *ti, unsigned int argc, char **argv)
/*
* Silently drop discards, avoiding -EOPNOTSUPP.
*/
- ti->num_discard_requests = 1;
+ ti->num_discard_bios = 1;
return 0;
}
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index bb2cd3c..7e46926 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -163,7 +163,6 @@ struct mapped_device {
* io objects are allocated from here.
*/
mempool_t *io_pool;
- mempool_t *tio_pool;
struct bio_set *bs;
@@ -197,7 +196,6 @@ struct mapped_device {
*/
struct dm_md_mempools {
mempool_t *io_pool;
- mempool_t *tio_pool;
struct bio_set *bs;
};
@@ -205,12 +203,6 @@ struct dm_md_mempools {
static struct kmem_cache *_io_cache;
static struct kmem_cache *_rq_tio_cache;
-/*
- * Unused now, and needs to be deleted. But since io_pool is overloaded and it's
- * still used for _io_cache, I'm leaving this for a later cleanup
- */
-static struct kmem_cache *_rq_bio_info_cache;
-
static int __init local_init(void)
{
int r = -ENOMEM;
@@ -224,13 +216,9 @@ static int __init local_init(void)
if (!_rq_tio_cache)
goto out_free_io_cache;
- _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0);
- if (!_rq_bio_info_cache)
- goto out_free_rq_tio_cache;
-
r = dm_uevent_init();
if (r)
- goto out_free_rq_bio_info_cache;
+ goto out_free_rq_tio_cache;
_major = major;
r = register_blkdev(_major, _name);
@@ -244,8 +232,6 @@ static int __init local_init(void)
out_uevent_exit:
dm_uevent_exit();
-out_free_rq_bio_info_cache:
- kmem_cache_destroy(_rq_bio_info_cache);
out_free_rq_tio_cache:
kmem_cache_destroy(_rq_tio_cache);
out_free_io_cache:
@@ -256,7 +242,6 @@ out_free_io_cache:
static void local_exit(void)
{
- kmem_cache_destroy(_rq_bio_info_cache);
kmem_cache_destroy(_rq_tio_cache);
kmem_cache_destroy(_io_cache);
unregister_blkdev(_major, _name);
@@ -448,12 +433,12 @@ static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
gfp_t gfp_mask)
{
- return mempool_alloc(md->tio_pool, gfp_mask);
+ return mempool_alloc(md->io_pool, gfp_mask);
}
static void free_rq_tio(struct dm_rq_target_io *tio)
{
- mempool_free(tio, tio->md->tio_pool);
+ mempool_free(tio, tio->md->io_pool);
}
static int md_in_flight(struct mapped_device *md)
@@ -985,12 +970,13 @@ int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
}
EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
-static void __map_bio(struct dm_target *ti, struct dm_target_io *tio)
+static void __map_bio(struct dm_target_io *tio)
{
int r;
sector_t sector;
struct mapped_device *md;
struct bio *clone = &tio->clone;
+ struct dm_target *ti = tio->ti;
clone->bi_end_io = clone_endio;
clone->bi_private = tio;
@@ -1031,32 +1017,54 @@ struct clone_info {
unsigned short idx;
};
+static void bio_setup_sector(struct bio *bio, sector_t sector, sector_t len)
+{
+ bio->bi_sector = sector;
+ bio->bi_size = to_bytes(len);
+}
+
+static void bio_setup_bv(struct bio *bio, unsigned short idx, unsigned short bv_count)
+{
+ bio->bi_idx = idx;
+ bio->bi_vcnt = idx + bv_count;
+ bio->bi_flags &= ~(1 << BIO_SEG_VALID);
+}
+
+static void clone_bio_integrity(struct bio *bio, struct bio *clone,
+ unsigned short idx, unsigned len, unsigned offset,
+ unsigned trim)
+{
+ if (!bio_integrity(bio))
+ return;
+
+ bio_integrity_clone(clone, bio, GFP_NOIO);
+
+ if (trim)
+ bio_integrity_trim(clone, bio_sector_offset(bio, idx, offset), len);
+}
+
/*
* Creates a little bio that just does part of a bvec.
*/
-static void split_bvec(struct dm_target_io *tio, struct bio *bio,
- sector_t sector, unsigned short idx, unsigned int offset,
- unsigned int len, struct bio_set *bs)
+static void clone_split_bio(struct dm_target_io *tio, struct bio *bio,
+ sector_t sector, unsigned short idx,
+ unsigned offset, unsigned len)
{
struct bio *clone = &tio->clone;
struct bio_vec *bv = bio->bi_io_vec + idx;
*clone->bi_io_vec = *bv;
- clone->bi_sector = sector;
+ bio_setup_sector(clone, sector, len);
+
clone->bi_bdev = bio->bi_bdev;
clone->bi_rw = bio->bi_rw;
clone->bi_vcnt = 1;
- clone->bi_size = to_bytes(len);
clone->bi_io_vec->bv_offset = offset;
clone->bi_io_vec->bv_len = clone->bi_size;
clone->bi_flags |= 1 << BIO_CLONED;
- if (bio_integrity(bio)) {
- bio_integrity_clone(clone, bio, GFP_NOIO);
- bio_integrity_trim(clone,
- bio_sector_offset(bio, idx, offset), len);
- }
+ clone_bio_integrity(bio, clone, idx, len, offset, 1);
}
/*
@@ -1064,29 +1072,23 @@ static void split_bvec(struct dm_target_io *tio, struct bio *bio,
*/
static void clone_bio(struct dm_target_io *tio, struct bio *bio,
sector_t sector, unsigned short idx,
- unsigned short bv_count, unsigned int len,
- struct bio_set *bs)
+ unsigned short bv_count, unsigned len)
{
struct bio *clone = &tio->clone;
+ unsigned trim = 0;
__bio_clone(clone, bio);
- clone->bi_sector = sector;
- clone->bi_idx = idx;
- clone->bi_vcnt = idx + bv_count;
- clone->bi_size = to_bytes(len);
- clone->bi_flags &= ~(1 << BIO_SEG_VALID);
-
- if (bio_integrity(bio)) {
- bio_integrity_clone(clone, bio, GFP_NOIO);
-
- if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
- bio_integrity_trim(clone,
- bio_sector_offset(bio, idx, 0), len);
- }
+ bio_setup_sector(clone, sector, len);
+ bio_setup_bv(clone, idx, bv_count);
+
+ if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
+ trim = 1;
+ clone_bio_integrity(bio, clone, idx, len, 0, trim);
}
static struct dm_target_io *alloc_tio(struct clone_info *ci,
- struct dm_target *ti, int nr_iovecs)
+ struct dm_target *ti, int nr_iovecs,
+ unsigned target_bio_nr)
{
struct dm_target_io *tio;
struct bio *clone;
@@ -1097,96 +1099,104 @@ static struct dm_target_io *alloc_tio(struct clone_info *ci,
tio->io = ci->io;
tio->ti = ti;
memset(&tio->info, 0, sizeof(tio->info));
- tio->target_request_nr = 0;
+ tio->target_bio_nr = target_bio_nr;
return tio;
}
-static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
- unsigned request_nr, sector_t len)
+static void __clone_and_map_simple_bio(struct clone_info *ci,
+ struct dm_target *ti,
+ unsigned target_bio_nr, sector_t len)
{
- struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs);
+ struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs, target_bio_nr);
struct bio *clone = &tio->clone;
- tio->target_request_nr = request_nr;
-
/*
* Discard requests require the bio's inline iovecs be initialized.
* ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush
* and discard, so no need for concern about wasted bvec allocations.
*/
-
__bio_clone(clone, ci->bio);
- if (len) {
- clone->bi_sector = ci->sector;
- clone->bi_size = to_bytes(len);
- }
+ if (len)
+ bio_setup_sector(clone, ci->sector, len);
- __map_bio(ti, tio);
+ __map_bio(tio);
}
-static void __issue_target_requests(struct clone_info *ci, struct dm_target *ti,
- unsigned num_requests, sector_t len)
+static void __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
+ unsigned num_bios, sector_t len)
{
- unsigned request_nr;
+ unsigned target_bio_nr;
- for (request_nr = 0; request_nr < num_requests; request_nr++)
- __issue_target_request(ci, ti, request_nr, len);
+ for (target_bio_nr = 0; target_bio_nr < num_bios; target_bio_nr++)
+ __clone_and_map_simple_bio(ci, ti, target_bio_nr, len);
}
-static int __clone_and_map_empty_flush(struct clone_info *ci)
+static int __send_empty_flush(struct clone_info *ci)
{
unsigned target_nr = 0;
struct dm_target *ti;
BUG_ON(bio_has_data(ci->bio));
while ((ti = dm_table_get_target(ci->map, target_nr++)))
- __issue_target_requests(ci, ti, ti->num_flush_requests, 0);
+ __send_duplicate_bios(ci, ti, ti->num_flush_bios, 0);
return 0;
}
-/*
- * Perform all io with a single clone.
- */
-static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti)
+static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti,
+ sector_t sector, int nr_iovecs,
+ unsigned short idx, unsigned short bv_count,
+ unsigned offset, unsigned len,
+ unsigned split_bvec)
{
struct bio *bio = ci->bio;
struct dm_target_io *tio;
+ unsigned target_bio_nr;
+ unsigned num_target_bios = 1;
+
+ /*
+ * Does the target want to receive duplicate copies of the bio?
+ */
+ if (bio_data_dir(bio) == WRITE && ti->num_write_bios)
+ num_target_bios = ti->num_write_bios(ti, bio);
- tio = alloc_tio(ci, ti, bio->bi_max_vecs);
- clone_bio(tio, bio, ci->sector, ci->idx, bio->bi_vcnt - ci->idx,
- ci->sector_count, ci->md->bs);
- __map_bio(ti, tio);
- ci->sector_count = 0;
+ for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) {
+ tio = alloc_tio(ci, ti, nr_iovecs, target_bio_nr);
+ if (split_bvec)
+ clone_split_bio(tio, bio, sector, idx, offset, len);
+ else
+ clone_bio(tio, bio, sector, idx, bv_count, len);
+ __map_bio(tio);
+ }
}
-typedef unsigned (*get_num_requests_fn)(struct dm_target *ti);
+typedef unsigned (*get_num_bios_fn)(struct dm_target *ti);
-static unsigned get_num_discard_requests(struct dm_target *ti)
+static unsigned get_num_discard_bios(struct dm_target *ti)
{
- return ti->num_discard_requests;
+ return ti->num_discard_bios;
}
-static unsigned get_num_write_same_requests(struct dm_target *ti)
+static unsigned get_num_write_same_bios(struct dm_target *ti)
{
- return ti->num_write_same_requests;
+ return ti->num_write_same_bios;
}
typedef bool (*is_split_required_fn)(struct dm_target *ti);
static bool is_split_required_for_discard(struct dm_target *ti)
{
- return ti->split_discard_requests;
+ return ti->split_discard_bios;
}
-static int __clone_and_map_changing_extent_only(struct clone_info *ci,
- get_num_requests_fn get_num_requests,
- is_split_required_fn is_split_required)
+static int __send_changing_extent_only(struct clone_info *ci,
+ get_num_bios_fn get_num_bios,
+ is_split_required_fn is_split_required)
{
struct dm_target *ti;
sector_t len;
- unsigned num_requests;
+ unsigned num_bios;
do {
ti = dm_table_find_target(ci->map, ci->sector);
@@ -1199,8 +1209,8 @@ static int __clone_and_map_changing_extent_only(struct clone_info *ci,
* reconfiguration might also have changed that since the
* check was performed.
*/
- num_requests = get_num_requests ? get_num_requests(ti) : 0;
- if (!num_requests)
+ num_bios = get_num_bios ? get_num_bios(ti) : 0;
+ if (!num_bios)
return -EOPNOTSUPP;
if (is_split_required && !is_split_required(ti))
@@ -1208,7 +1218,7 @@ static int __clone_and_map_changing_extent_only(struct clone_info *ci,
else
len = min(ci->sector_count, max_io_len(ci->sector, ti));
- __issue_target_requests(ci, ti, num_requests, len);
+ __send_duplicate_bios(ci, ti, num_bios, len);
ci->sector += len;
} while (ci->sector_count -= len);
@@ -1216,108 +1226,129 @@ static int __clone_and_map_changing_extent_only(struct clone_info *ci,
return 0;
}
-static int __clone_and_map_discard(struct clone_info *ci)
+static int __send_discard(struct clone_info *ci)
{
- return __clone_and_map_changing_extent_only(ci, get_num_discard_requests,
- is_split_required_for_discard);
+ return __send_changing_extent_only(ci, get_num_discard_bios,
+ is_split_required_for_discard);
}
-static int __clone_and_map_write_same(struct clone_info *ci)
+static int __send_write_same(struct clone_info *ci)
{
- return __clone_and_map_changing_extent_only(ci, get_num_write_same_requests, NULL);
+ return __send_changing_extent_only(ci, get_num_write_same_bios, NULL);
}
-static int __clone_and_map(struct clone_info *ci)
+/*
+ * Find maximum number of sectors / bvecs we can process with a single bio.
+ */
+static sector_t __len_within_target(struct clone_info *ci, sector_t max, int *idx)
{
struct bio *bio = ci->bio;
- struct dm_target *ti;
- sector_t len = 0, max;
- struct dm_target_io *tio;
-
- if (unlikely(bio->bi_rw & REQ_DISCARD))
- return __clone_and_map_discard(ci);
- else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
- return __clone_and_map_write_same(ci);
+ sector_t bv_len, total_len = 0;
- ti = dm_table_find_target(ci->map, ci->sector);
- if (!dm_target_is_valid(ti))
- return -EIO;
+ for (*idx = ci->idx; max && (*idx < bio->bi_vcnt); (*idx)++) {
+ bv_len = to_sector(bio->bi_io_vec[*idx].bv_len);
- max = max_io_len(ci->sector, ti);
+ if (bv_len > max)
+ break;
- if (ci->sector_count <= max) {
- /*
- * Optimise for the simple case where we can do all of
- * the remaining io with a single clone.
- */
- __clone_and_map_simple(ci, ti);
+ max -= bv_len;
+ total_len += bv_len;
+ }
- } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
- /*
- * There are some bvecs that don't span targets.
- * Do as many of these as possible.
- */
- int i;
- sector_t remaining = max;
- sector_t bv_len;
+ return total_len;
+}
- for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) {
- bv_len = to_sector(bio->bi_io_vec[i].bv_len);
+static int __split_bvec_across_targets(struct clone_info *ci,
+ struct dm_target *ti, sector_t max)
+{
+ struct bio *bio = ci->bio;
+ struct bio_vec *bv = bio->bi_io_vec + ci->idx;
+ sector_t remaining = to_sector(bv->bv_len);
+ unsigned offset = 0;
+ sector_t len;
- if (bv_len > remaining)
- break;
+ do {
+ if (offset) {
+ ti = dm_table_find_target(ci->map, ci->sector);
+ if (!dm_target_is_valid(ti))
+ return -EIO;
- remaining -= bv_len;
- len += bv_len;
+ max = max_io_len(ci->sector, ti);
}
- tio = alloc_tio(ci, ti, bio->bi_max_vecs);
- clone_bio(tio, bio, ci->sector, ci->idx, i - ci->idx, len,
- ci->md->bs);
- __map_bio(ti, tio);
+ len = min(remaining, max);
+
+ __clone_and_map_data_bio(ci, ti, ci->sector, 1, ci->idx, 0,
+ bv->bv_offset + offset, len, 1);
ci->sector += len;
ci->sector_count -= len;
- ci->idx = i;
+ offset += to_bytes(len);
+ } while (remaining -= len);
- } else {
- /*
- * Handle a bvec that must be split between two or more targets.
- */
- struct bio_vec *bv = bio->bi_io_vec + ci->idx;
- sector_t remaining = to_sector(bv->bv_len);
- unsigned int offset = 0;
+ ci->idx++;
+
+ return 0;
+}
+
+/*
+ * Select the correct strategy for processing a non-flush bio.
+ */
+static int __split_and_process_non_flush(struct clone_info *ci)
+{
+ struct bio *bio = ci->bio;
+ struct dm_target *ti;
+ sector_t len, max;
+ int idx;
+
+ if (unlikely(bio->bi_rw & REQ_DISCARD))
+ return __send_discard(ci);
+ else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
+ return __send_write_same(ci);
- do {
- if (offset) {
- ti = dm_table_find_target(ci->map, ci->sector);
- if (!dm_target_is_valid(ti))
- return -EIO;
+ ti = dm_table_find_target(ci->map, ci->sector);
+ if (!dm_target_is_valid(ti))
+ return -EIO;
- max = max_io_len(ci->sector, ti);
- }
+ max = max_io_len(ci->sector, ti);
- len = min(remaining, max);
+ /*
+ * Optimise for the simple case where we can do all of
+ * the remaining io with a single clone.
+ */
+ if (ci->sector_count <= max) {
+ __clone_and_map_data_bio(ci, ti, ci->sector, bio->bi_max_vecs,
+ ci->idx, bio->bi_vcnt - ci->idx, 0,
+ ci->sector_count, 0);
+ ci->sector_count = 0;
+ return 0;
+ }
- tio = alloc_tio(ci, ti, 1);
- split_bvec(tio, bio, ci->sector, ci->idx,
- bv->bv_offset + offset, len, ci->md->bs);
+ /*
+ * There are some bvecs that don't span targets.
+ * Do as many of these as possible.
+ */
+ if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
+ len = __len_within_target(ci, max, &idx);
- __map_bio(ti, tio);
+ __clone_and_map_data_bio(ci, ti, ci->sector, bio->bi_max_vecs,
+ ci->idx, idx - ci->idx, 0, len, 0);
- ci->sector += len;
- ci->sector_count -= len;
- offset += to_bytes(len);
- } while (remaining -= len);
+ ci->sector += len;
+ ci->sector_count -= len;
+ ci->idx = idx;
- ci->idx++;
+ return 0;
}
- return 0;
+ /*
+ * Handle a bvec that must be split between two or more targets.
+ */
+ return __split_bvec_across_targets(ci, ti, max);
}
/*
- * Split the bio into several clones and submit it to targets.
+ * Entry point to split a bio into clones and submit them to the targets.
*/
static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
{
@@ -1341,16 +1372,17 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
ci.idx = bio->bi_idx;
start_io_acct(ci.io);
+
if (bio->bi_rw & REQ_FLUSH) {
ci.bio = &ci.md->flush_bio;
ci.sector_count = 0;
- error = __clone_and_map_empty_flush(&ci);
+ error = __send_empty_flush(&ci);
/* dec_pending submits any data associated with flush */
} else {
ci.bio = bio;
ci.sector_count = bio_sectors(bio);
while (ci.sector_count && !error)
- error = __clone_and_map(&ci);
+ error = __split_and_process_non_flush(&ci);
}
/* drop the extra reference count */
@@ -1923,8 +1955,6 @@ static void free_dev(struct mapped_device *md)
unlock_fs(md);
bdput(md->bdev);
destroy_workqueue(md->wq);
- if (md->tio_pool)
- mempool_destroy(md->tio_pool);
if (md->io_pool)
mempool_destroy(md->io_pool);
if (md->bs)
@@ -1947,24 +1977,33 @@ static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
{
struct dm_md_mempools *p = dm_table_get_md_mempools(t);
- if (md->io_pool && (md->tio_pool || dm_table_get_type(t) == DM_TYPE_BIO_BASED) && md->bs) {
- /*
- * The md already has necessary mempools. Reload just the
- * bioset because front_pad may have changed because
- * a different table was loaded.
- */
- bioset_free(md->bs);
- md->bs = p->bs;
- p->bs = NULL;
+ if (md->io_pool && md->bs) {
+ /* The md already has necessary mempools. */
+ if (dm_table_get_type(t) == DM_TYPE_BIO_BASED) {
+ /*
+ * Reload bioset because front_pad may have changed
+ * because a different table was loaded.
+ */
+ bioset_free(md->bs);
+ md->bs = p->bs;
+ p->bs = NULL;
+ } else if (dm_table_get_type(t) == DM_TYPE_REQUEST_BASED) {
+ /*
+ * There's no need to reload with request-based dm
+ * because the size of front_pad doesn't change.
+ * Note for future: If you are to reload bioset,
+ * prep-ed requests in the queue may refer
+ * to bio from the old bioset, so you must walk
+ * through the queue to unprep.
+ */
+ }
goto out;
}
- BUG_ON(!p || md->io_pool || md->tio_pool || md->bs);
+ BUG_ON(!p || md->io_pool || md->bs);
md->io_pool = p->io_pool;
p->io_pool = NULL;
- md->tio_pool = p->tio_pool;
- p->tio_pool = NULL;
md->bs = p->bs;
p->bs = NULL;
@@ -2395,7 +2434,7 @@ static void dm_queue_flush(struct mapped_device *md)
*/
struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
{
- struct dm_table *live_map, *map = ERR_PTR(-EINVAL);
+ struct dm_table *live_map = NULL, *map = ERR_PTR(-EINVAL);
struct queue_limits limits;
int r;
@@ -2418,10 +2457,12 @@ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
dm_table_put(live_map);
}
- r = dm_calculate_queue_limits(table, &limits);
- if (r) {
- map = ERR_PTR(r);
- goto out;
+ if (!live_map) {
+ r = dm_calculate_queue_limits(table, &limits);
+ if (r) {
+ map = ERR_PTR(r);
+ goto out;
+ }
}
map = __bind(md, table, &limits);
@@ -2719,52 +2760,42 @@ EXPORT_SYMBOL_GPL(dm_noflush_suspending);
struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, unsigned per_bio_data_size)
{
- struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL);
- unsigned int pool_size = (type == DM_TYPE_BIO_BASED) ? 16 : MIN_IOS;
+ struct dm_md_mempools *pools = kzalloc(sizeof(*pools), GFP_KERNEL);
+ struct kmem_cache *cachep;
+ unsigned int pool_size;
+ unsigned int front_pad;
if (!pools)
return NULL;
- per_bio_data_size = roundup(per_bio_data_size, __alignof__(struct dm_target_io));
+ if (type == DM_TYPE_BIO_BASED) {
+ cachep = _io_cache;
+ pool_size = 16;
+ front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
+ } else if (type == DM_TYPE_REQUEST_BASED) {
+ cachep = _rq_tio_cache;
+ pool_size = MIN_IOS;
+ front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
+ /* per_bio_data_size is not used. See __bind_mempools(). */
+ WARN_ON(per_bio_data_size != 0);
+ } else
+ goto out;
- pools->io_pool = (type == DM_TYPE_BIO_BASED) ?
- mempool_create_slab_pool(MIN_IOS, _io_cache) :
- mempool_create_slab_pool(MIN_IOS, _rq_bio_info_cache);
+ pools->io_pool = mempool_create_slab_pool(MIN_IOS, cachep);
if (!pools->io_pool)
- goto free_pools_and_out;
-
- pools->tio_pool = NULL;
- if (type == DM_TYPE_REQUEST_BASED) {
- pools->tio_pool = mempool_create_slab_pool(MIN_IOS, _rq_tio_cache);
- if (!pools->tio_pool)
- goto free_io_pool_and_out;
- }
+ goto out;
- pools->bs = (type == DM_TYPE_BIO_BASED) ?
- bioset_create(pool_size,
- per_bio_data_size + offsetof(struct dm_target_io, clone)) :
- bioset_create(pool_size,
- offsetof(struct dm_rq_clone_bio_info, clone));
+ pools->bs = bioset_create(pool_size, front_pad);
if (!pools->bs)
- goto free_tio_pool_and_out;
+ goto out;
if (integrity && bioset_integrity_create(pools->bs, pool_size))
- goto free_bioset_and_out;
+ goto out;
return pools;
-free_bioset_and_out:
- bioset_free(pools->bs);
-
-free_tio_pool_and_out:
- if (pools->tio_pool)
- mempool_destroy(pools->tio_pool);
-
-free_io_pool_and_out:
- mempool_destroy(pools->io_pool);
-
-free_pools_and_out:
- kfree(pools);
+out:
+ dm_free_md_mempools(pools);
return NULL;
}
@@ -2777,9 +2808,6 @@ void dm_free_md_mempools(struct dm_md_mempools *pools)
if (pools->io_pool)
mempool_destroy(pools->io_pool);
- if (pools->tio_pool)
- mempool_destroy(pools->tio_pool);
-
if (pools->bs)
bioset_free(pools->bs);
diff --git a/drivers/md/persistent-data/Kconfig b/drivers/md/persistent-data/Kconfig
index ceb3590..19b2687 100644
--- a/drivers/md/persistent-data/Kconfig
+++ b/drivers/md/persistent-data/Kconfig
@@ -1,6 +1,6 @@
config DM_PERSISTENT_DATA
tristate
- depends on BLK_DEV_DM && EXPERIMENTAL
+ depends on BLK_DEV_DM
select LIBCRC32C
select DM_BUFIO
---help---
diff --git a/drivers/md/persistent-data/Makefile b/drivers/md/persistent-data/Makefile
index d8e7cb7..ff52879 100644
--- a/drivers/md/persistent-data/Makefile
+++ b/drivers/md/persistent-data/Makefile
@@ -1,5 +1,7 @@
obj-$(CONFIG_DM_PERSISTENT_DATA) += dm-persistent-data.o
dm-persistent-data-objs := \
+ dm-array.o \
+ dm-bitset.o \
dm-block-manager.o \
dm-space-map-common.o \
dm-space-map-disk.o \
diff --git a/drivers/md/persistent-data/dm-array.c b/drivers/md/persistent-data/dm-array.c
new file mode 100644
index 0000000..172147e
--- /dev/null
+++ b/drivers/md/persistent-data/dm-array.c
@@ -0,0 +1,808 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-array.h"
+#include "dm-space-map.h"
+#include "dm-transaction-manager.h"
+
+#include <linux/export.h>
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "array"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * The array is implemented as a fully populated btree, which points to
+ * blocks that contain the packed values. This is more space efficient
+ * than just using a btree since we don't store 1 key per value.
+ */
+struct array_block {
+ __le32 csum;
+ __le32 max_entries;
+ __le32 nr_entries;
+ __le32 value_size;
+ __le64 blocknr; /* Block this node is supposed to live in. */
+} __packed;
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Validator methods. As usual we calculate a checksum, and also write the
+ * block location into the header (paranoia about ssds remapping areas by
+ * mistake).
+ */
+#define CSUM_XOR 595846735
+
+static void array_block_prepare_for_write(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t size_of_block)
+{
+ struct array_block *bh_le = dm_block_data(b);
+
+ bh_le->blocknr = cpu_to_le64(dm_block_location(b));
+ bh_le->csum = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
+ size_of_block - sizeof(__le32),
+ CSUM_XOR));
+}
+
+static int array_block_check(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t size_of_block)
+{
+ struct array_block *bh_le = dm_block_data(b);
+ __le32 csum_disk;
+
+ if (dm_block_location(b) != le64_to_cpu(bh_le->blocknr)) {
+ DMERR_LIMIT("array_block_check failed: blocknr %llu != wanted %llu",
+ (unsigned long long) le64_to_cpu(bh_le->blocknr),
+ (unsigned long long) dm_block_location(b));
+ return -ENOTBLK;
+ }
+
+ csum_disk = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
+ size_of_block - sizeof(__le32),
+ CSUM_XOR));
+ if (csum_disk != bh_le->csum) {
+ DMERR_LIMIT("array_block_check failed: csum %u != wanted %u",
+ (unsigned) le32_to_cpu(csum_disk),
+ (unsigned) le32_to_cpu(bh_le->csum));
+ return -EILSEQ;
+ }
+
+ return 0;
+}
+
+static struct dm_block_validator array_validator = {
+ .name = "array",
+ .prepare_for_write = array_block_prepare_for_write,
+ .check = array_block_check
+};
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Functions for manipulating the array blocks.
+ */
+
+/*
+ * Returns a pointer to a value within an array block.
+ *
+ * index - The index into _this_ specific block.
+ */
+static void *element_at(struct dm_array_info *info, struct array_block *ab,
+ unsigned index)
+{
+ unsigned char *entry = (unsigned char *) (ab + 1);
+
+ entry += index * info->value_type.size;
+
+ return entry;
+}
+
+/*
+ * Utility function that calls one of the value_type methods on every value
+ * in an array block.
+ */
+static void on_entries(struct dm_array_info *info, struct array_block *ab,
+ void (*fn)(void *, const void *))
+{
+ unsigned i, nr_entries = le32_to_cpu(ab->nr_entries);
+
+ for (i = 0; i < nr_entries; i++)
+ fn(info->value_type.context, element_at(info, ab, i));
+}
+
+/*
+ * Increment every value in an array block.
+ */
+static void inc_ablock_entries(struct dm_array_info *info, struct array_block *ab)
+{
+ struct dm_btree_value_type *vt = &info->value_type;
+
+ if (vt->inc)
+ on_entries(info, ab, vt->inc);
+}
+
+/*
+ * Decrement every value in an array block.
+ */
+static void dec_ablock_entries(struct dm_array_info *info, struct array_block *ab)
+{
+ struct dm_btree_value_type *vt = &info->value_type;
+
+ if (vt->dec)
+ on_entries(info, ab, vt->dec);
+}
+
+/*
+ * Each array block can hold this many values.
+ */
+static uint32_t calc_max_entries(size_t value_size, size_t size_of_block)
+{
+ return (size_of_block - sizeof(struct array_block)) / value_size;
+}
+
+/*
+ * Allocate a new array block. The caller will need to unlock block.
+ */
+static int alloc_ablock(struct dm_array_info *info, size_t size_of_block,
+ uint32_t max_entries,
+ struct dm_block **block, struct array_block **ab)
+{
+ int r;
+
+ r = dm_tm_new_block(info->btree_info.tm, &array_validator, block);
+ if (r)
+ return r;
+
+ (*ab) = dm_block_data(*block);
+ (*ab)->max_entries = cpu_to_le32(max_entries);
+ (*ab)->nr_entries = cpu_to_le32(0);
+ (*ab)->value_size = cpu_to_le32(info->value_type.size);
+
+ return 0;
+}
+
+/*
+ * Pad an array block out with a particular value. Every instance will
+ * cause an increment of the value_type. new_nr must always be more than
+ * the current number of entries.
+ */
+static void fill_ablock(struct dm_array_info *info, struct array_block *ab,
+ const void *value, unsigned new_nr)
+{
+ unsigned i;
+ uint32_t nr_entries;
+ struct dm_btree_value_type *vt = &info->value_type;
+
+ BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
+ BUG_ON(new_nr < le32_to_cpu(ab->nr_entries));
+
+ nr_entries = le32_to_cpu(ab->nr_entries);
+ for (i = nr_entries; i < new_nr; i++) {
+ if (vt->inc)
+ vt->inc(vt->context, value);
+ memcpy(element_at(info, ab, i), value, vt->size);
+ }
+ ab->nr_entries = cpu_to_le32(new_nr);
+}
+
+/*
+ * Remove some entries from the back of an array block. Every value
+ * removed will be decremented. new_nr must be <= the current number of
+ * entries.
+ */
+static void trim_ablock(struct dm_array_info *info, struct array_block *ab,
+ unsigned new_nr)
+{
+ unsigned i;
+ uint32_t nr_entries;
+ struct dm_btree_value_type *vt = &info->value_type;
+
+ BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
+ BUG_ON(new_nr > le32_to_cpu(ab->nr_entries));
+
+ nr_entries = le32_to_cpu(ab->nr_entries);
+ for (i = nr_entries; i > new_nr; i--)
+ if (vt->dec)
+ vt->dec(vt->context, element_at(info, ab, i - 1));
+ ab->nr_entries = cpu_to_le32(new_nr);
+}
+
+/*
+ * Read locks a block, and coerces it to an array block. The caller must
+ * unlock 'block' when finished.
+ */
+static int get_ablock(struct dm_array_info *info, dm_block_t b,
+ struct dm_block **block, struct array_block **ab)
+{
+ int r;
+
+ r = dm_tm_read_lock(info->btree_info.tm, b, &array_validator, block);
+ if (r)
+ return r;
+
+ *ab = dm_block_data(*block);
+ return 0;
+}
+
+/*
+ * Unlocks an array block.
+ */
+static int unlock_ablock(struct dm_array_info *info, struct dm_block *block)
+{
+ return dm_tm_unlock(info->btree_info.tm, block);
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Btree manipulation.
+ */
+
+/*
+ * Looks up an array block in the btree, and then read locks it.
+ *
+ * index is the index of the index of the array_block, (ie. the array index
+ * / max_entries).
+ */
+static int lookup_ablock(struct dm_array_info *info, dm_block_t root,
+ unsigned index, struct dm_block **block,
+ struct array_block **ab)
+{
+ int r;
+ uint64_t key = index;
+ __le64 block_le;
+
+ r = dm_btree_lookup(&info->btree_info, root, &key, &block_le);
+ if (r)
+ return r;
+
+ return get_ablock(info, le64_to_cpu(block_le), block, ab);
+}
+
+/*
+ * Insert an array block into the btree. The block is _not_ unlocked.
+ */
+static int insert_ablock(struct dm_array_info *info, uint64_t index,
+ struct dm_block *block, dm_block_t *root)
+{
+ __le64 block_le = cpu_to_le64(dm_block_location(block));
+
+ __dm_bless_for_disk(block_le);
+ return dm_btree_insert(&info->btree_info, *root, &index, &block_le, root);
+}
+
+/*
+ * Looks up an array block in the btree. Then shadows it, and updates the
+ * btree to point to this new shadow. 'root' is an input/output parameter
+ * for both the current root block, and the new one.
+ */
+static int shadow_ablock(struct dm_array_info *info, dm_block_t *root,
+ unsigned index, struct dm_block **block,
+ struct array_block **ab)
+{
+ int r, inc;
+ uint64_t key = index;
+ dm_block_t b;
+ __le64 block_le;
+
+ /*
+ * lookup
+ */
+ r = dm_btree_lookup(&info->btree_info, *root, &key, &block_le);
+ if (r)
+ return r;
+ b = le64_to_cpu(block_le);
+
+ /*
+ * shadow
+ */
+ r = dm_tm_shadow_block(info->btree_info.tm, b,
+ &array_validator, block, &inc);
+ if (r)
+ return r;
+
+ *ab = dm_block_data(*block);
+ if (inc)
+ inc_ablock_entries(info, *ab);
+
+ /*
+ * Reinsert.
+ *
+ * The shadow op will often be a noop. Only insert if it really
+ * copied data.
+ */
+ if (dm_block_location(*block) != b)
+ r = insert_ablock(info, index, *block, root);
+
+ return r;
+}
+
+/*
+ * Allocate an new array block, and fill it with some values.
+ */
+static int insert_new_ablock(struct dm_array_info *info, size_t size_of_block,
+ uint32_t max_entries,
+ unsigned block_index, uint32_t nr,
+ const void *value, dm_block_t *root)
+{
+ int r;
+ struct dm_block *block;
+ struct array_block *ab;
+
+ r = alloc_ablock(info, size_of_block, max_entries, &block, &ab);
+ if (r)
+ return r;
+
+ fill_ablock(info, ab, value, nr);
+ r = insert_ablock(info, block_index, block, root);
+ unlock_ablock(info, block);
+
+ return r;
+}
+
+static int insert_full_ablocks(struct dm_array_info *info, size_t size_of_block,
+ unsigned begin_block, unsigned end_block,
+ unsigned max_entries, const void *value,
+ dm_block_t *root)
+{
+ int r = 0;
+
+ for (; !r && begin_block != end_block; begin_block++)
+ r = insert_new_ablock(info, size_of_block, max_entries, begin_block, max_entries, value, root);
+
+ return r;
+}
+
+/*
+ * There are a bunch of functions involved with resizing an array. This
+ * structure holds information that commonly needed by them. Purely here
+ * to reduce parameter count.
+ */
+struct resize {
+ /*
+ * Describes the array.
+ */
+ struct dm_array_info *info;
+
+ /*
+ * The current root of the array. This gets updated.
+ */
+ dm_block_t root;
+
+ /*
+ * Metadata block size. Used to calculate the nr entries in an
+ * array block.
+ */
+ size_t size_of_block;
+
+ /*
+ * Maximum nr entries in an array block.
+ */
+ unsigned max_entries;
+
+ /*
+ * nr of completely full blocks in the array.
+ *
+ * 'old' refers to before the resize, 'new' after.
+ */
+ unsigned old_nr_full_blocks, new_nr_full_blocks;
+
+ /*
+ * Number of entries in the final block. 0 iff only full blocks in
+ * the array.
+ */
+ unsigned old_nr_entries_in_last_block, new_nr_entries_in_last_block;
+
+ /*
+ * The default value used when growing the array.
+ */
+ const void *value;
+};
+
+/*
+ * Removes a consecutive set of array blocks from the btree. The values
+ * in block are decremented as a side effect of the btree remove.
+ *
+ * begin_index - the index of the first array block to remove.
+ * end_index - the one-past-the-end value. ie. this block is not removed.
+ */
+static int drop_blocks(struct resize *resize, unsigned begin_index,
+ unsigned end_index)
+{
+ int r;
+
+ while (begin_index != end_index) {
+ uint64_t key = begin_index++;
+ r = dm_btree_remove(&resize->info->btree_info, resize->root,
+ &key, &resize->root);
+ if (r)
+ return r;
+ }
+
+ return 0;
+}
+
+/*
+ * Calculates how many blocks are needed for the array.
+ */
+static unsigned total_nr_blocks_needed(unsigned nr_full_blocks,
+ unsigned nr_entries_in_last_block)
+{
+ return nr_full_blocks + (nr_entries_in_last_block ? 1 : 0);
+}
+
+/*
+ * Shrink an array.
+ */
+static int shrink(struct resize *resize)
+{
+ int r;
+ unsigned begin, end;
+ struct dm_block *block;
+ struct array_block *ab;
+
+ /*
+ * Lose some blocks from the back?
+ */
+ if (resize->new_nr_full_blocks < resize->old_nr_full_blocks) {
+ begin = total_nr_blocks_needed(resize->new_nr_full_blocks,
+ resize->new_nr_entries_in_last_block);
+ end = total_nr_blocks_needed(resize->old_nr_full_blocks,
+ resize->old_nr_entries_in_last_block);
+
+ r = drop_blocks(resize, begin, end);
+ if (r)
+ return r;
+ }
+
+ /*
+ * Trim the new tail block
+ */
+ if (resize->new_nr_entries_in_last_block) {
+ r = shadow_ablock(resize->info, &resize->root,
+ resize->new_nr_full_blocks, &block, &ab);
+ if (r)
+ return r;
+
+ trim_ablock(resize->info, ab, resize->new_nr_entries_in_last_block);
+ unlock_ablock(resize->info, block);
+ }
+
+ return 0;
+}
+
+/*
+ * Grow an array.
+ */
+static int grow_extend_tail_block(struct resize *resize, uint32_t new_nr_entries)
+{
+ int r;
+ struct dm_block *block;
+ struct array_block *ab;
+
+ r = shadow_ablock(resize->info, &resize->root,
+ resize->old_nr_full_blocks, &block, &ab);
+ if (r)
+ return r;
+
+ fill_ablock(resize->info, ab, resize->value, new_nr_entries);
+ unlock_ablock(resize->info, block);
+
+ return r;
+}
+
+static int grow_add_tail_block(struct resize *resize)
+{
+ return insert_new_ablock(resize->info, resize->size_of_block,
+ resize->max_entries,
+ resize->new_nr_full_blocks,
+ resize->new_nr_entries_in_last_block,
+ resize->value, &resize->root);
+}
+
+static int grow_needs_more_blocks(struct resize *resize)
+{
+ int r;
+
+ if (resize->old_nr_entries_in_last_block > 0) {
+ r = grow_extend_tail_block(resize, resize->max_entries);
+ if (r)
+ return r;
+ }
+
+ r = insert_full_ablocks(resize->info, resize->size_of_block,
+ resize->old_nr_full_blocks,
+ resize->new_nr_full_blocks,
+ resize->max_entries, resize->value,
+ &resize->root);
+ if (r)
+ return r;
+
+ if (resize->new_nr_entries_in_last_block)
+ r = grow_add_tail_block(resize);
+
+ return r;
+}
+
+static int grow(struct resize *resize)
+{
+ if (resize->new_nr_full_blocks > resize->old_nr_full_blocks)
+ return grow_needs_more_blocks(resize);
+
+ else if (resize->old_nr_entries_in_last_block)
+ return grow_extend_tail_block(resize, resize->new_nr_entries_in_last_block);
+
+ else
+ return grow_add_tail_block(resize);
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * These are the value_type functions for the btree elements, which point
+ * to array blocks.
+ */
+static void block_inc(void *context, const void *value)
+{
+ __le64 block_le;
+ struct dm_array_info *info = context;
+
+ memcpy(&block_le, value, sizeof(block_le));
+ dm_tm_inc(info->btree_info.tm, le64_to_cpu(block_le));
+}
+
+static void block_dec(void *context, const void *value)
+{
+ int r;
+ uint64_t b;
+ __le64 block_le;
+ uint32_t ref_count;
+ struct dm_block *block;
+ struct array_block *ab;
+ struct dm_array_info *info = context;
+
+ memcpy(&block_le, value, sizeof(block_le));
+ b = le64_to_cpu(block_le);
+
+ r = dm_tm_ref(info->btree_info.tm, b, &ref_count);
+ if (r) {
+ DMERR_LIMIT("couldn't get reference count for block %llu",
+ (unsigned long long) b);
+ return;
+ }
+
+ if (ref_count == 1) {
+ /*
+ * We're about to drop the last reference to this ablock.
+ * So we need to decrement the ref count of the contents.
+ */
+ r = get_ablock(info, b, &block, &ab);
+ if (r) {
+ DMERR_LIMIT("couldn't get array block %llu",
+ (unsigned long long) b);
+ return;
+ }
+
+ dec_ablock_entries(info, ab);
+ unlock_ablock(info, block);
+ }
+
+ dm_tm_dec(info->btree_info.tm, b);
+}
+
+static int block_equal(void *context, const void *value1, const void *value2)
+{
+ return !memcmp(value1, value2, sizeof(__le64));
+}
+
+/*----------------------------------------------------------------*/
+
+void dm_array_info_init(struct dm_array_info *info,
+ struct dm_transaction_manager *tm,
+ struct dm_btree_value_type *vt)
+{
+ struct dm_btree_value_type *bvt = &info->btree_info.value_type;
+
+ memcpy(&info->value_type, vt, sizeof(info->value_type));
+ info->btree_info.tm = tm;
+ info->btree_info.levels = 1;
+
+ bvt->context = info;
+ bvt->size = sizeof(__le64);
+ bvt->inc = block_inc;
+ bvt->dec = block_dec;
+ bvt->equal = block_equal;
+}
+EXPORT_SYMBOL_GPL(dm_array_info_init);
+
+int dm_array_empty(struct dm_array_info *info, dm_block_t *root)
+{
+ return dm_btree_empty(&info->btree_info, root);
+}
+EXPORT_SYMBOL_GPL(dm_array_empty);
+
+static int array_resize(struct dm_array_info *info, dm_block_t root,
+ uint32_t old_size, uint32_t new_size,
+ const void *value, dm_block_t *new_root)
+{
+ int r;
+ struct resize resize;
+
+ if (old_size == new_size)
+ return 0;
+
+ resize.info = info;
+ resize.root = root;
+ resize.size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
+ resize.max_entries = calc_max_entries(info->value_type.size,
+ resize.size_of_block);
+
+ resize.old_nr_full_blocks = old_size / resize.max_entries;
+ resize.old_nr_entries_in_last_block = old_size % resize.max_entries;
+ resize.new_nr_full_blocks = new_size / resize.max_entries;
+ resize.new_nr_entries_in_last_block = new_size % resize.max_entries;
+ resize.value = value;
+
+ r = ((new_size > old_size) ? grow : shrink)(&resize);
+ if (r)
+ return r;
+
+ *new_root = resize.root;
+ return 0;
+}
+
+int dm_array_resize(struct dm_array_info *info, dm_block_t root,
+ uint32_t old_size, uint32_t new_size,
+ const void *value, dm_block_t *new_root)
+ __dm_written_to_disk(value)
+{
+ int r = array_resize(info, root, old_size, new_size, value, new_root);
+ __dm_unbless_for_disk(value);
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_array_resize);
+
+int dm_array_del(struct dm_array_info *info, dm_block_t root)
+{
+ return dm_btree_del(&info->btree_info, root);
+}
+EXPORT_SYMBOL_GPL(dm_array_del);
+
+int dm_array_get_value(struct dm_array_info *info, dm_block_t root,
+ uint32_t index, void *value_le)
+{
+ int r;
+ struct dm_block *block;
+ struct array_block *ab;
+ size_t size_of_block;
+ unsigned entry, max_entries;
+
+ size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
+ max_entries = calc_max_entries(info->value_type.size, size_of_block);
+
+ r = lookup_ablock(info, root, index / max_entries, &block, &ab);
+ if (r)
+ return r;
+
+ entry = index % max_entries;
+ if (entry >= le32_to_cpu(ab->nr_entries))
+ r = -ENODATA;
+ else
+ memcpy(value_le, element_at(info, ab, entry),
+ info->value_type.size);
+
+ unlock_ablock(info, block);
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_array_get_value);
+
+static int array_set_value(struct dm_array_info *info, dm_block_t root,
+ uint32_t index, const void *value, dm_block_t *new_root)
+{
+ int r;
+ struct dm_block *block;
+ struct array_block *ab;
+ size_t size_of_block;
+ unsigned max_entries;
+ unsigned entry;
+ void *old_value;
+ struct dm_btree_value_type *vt = &info->value_type;
+
+ size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
+ max_entries = calc_max_entries(info->value_type.size, size_of_block);
+
+ r = shadow_ablock(info, &root, index / max_entries, &block, &ab);
+ if (r)
+ return r;
+ *new_root = root;
+
+ entry = index % max_entries;
+ if (entry >= le32_to_cpu(ab->nr_entries)) {
+ r = -ENODATA;
+ goto out;
+ }
+
+ old_value = element_at(info, ab, entry);
+ if (vt->dec &&
+ (!vt->equal || !vt->equal(vt->context, old_value, value))) {
+ vt->dec(vt->context, old_value);
+ if (vt->inc)
+ vt->inc(vt->context, value);
+ }
+
+ memcpy(old_value, value, info->value_type.size);
+
+out:
+ unlock_ablock(info, block);
+ return r;
+}
+
+int dm_array_set_value(struct dm_array_info *info, dm_block_t root,
+ uint32_t index, const void *value, dm_block_t *new_root)
+ __dm_written_to_disk(value)
+{
+ int r;
+
+ r = array_set_value(info, root, index, value, new_root);
+ __dm_unbless_for_disk(value);
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_array_set_value);
+
+struct walk_info {
+ struct dm_array_info *info;
+ int (*fn)(void *context, uint64_t key, void *leaf);
+ void *context;
+};
+
+static int walk_ablock(void *context, uint64_t *keys, void *leaf)
+{
+ struct walk_info *wi = context;
+
+ int r;
+ unsigned i;
+ __le64 block_le;
+ unsigned nr_entries, max_entries;
+ struct dm_block *block;
+ struct array_block *ab;
+
+ memcpy(&block_le, leaf, sizeof(block_le));
+ r = get_ablock(wi->info, le64_to_cpu(block_le), &block, &ab);
+ if (r)
+ return r;
+
+ max_entries = le32_to_cpu(ab->max_entries);
+ nr_entries = le32_to_cpu(ab->nr_entries);
+ for (i = 0; i < nr_entries; i++) {
+ r = wi->fn(wi->context, keys[0] * max_entries + i,
+ element_at(wi->info, ab, i));
+
+ if (r)
+ break;
+ }
+
+ unlock_ablock(wi->info, block);
+ return r;
+}
+
+int dm_array_walk(struct dm_array_info *info, dm_block_t root,
+ int (*fn)(void *, uint64_t key, void *leaf),
+ void *context)
+{
+ struct walk_info wi;
+
+ wi.info = info;
+ wi.fn = fn;
+ wi.context = context;
+
+ return dm_btree_walk(&info->btree_info, root, walk_ablock, &wi);
+}
+EXPORT_SYMBOL_GPL(dm_array_walk);
+
+/*----------------------------------------------------------------*/
diff --git a/drivers/md/persistent-data/dm-array.h b/drivers/md/persistent-data/dm-array.h
new file mode 100644
index 0000000..ea177d6
--- /dev/null
+++ b/drivers/md/persistent-data/dm-array.h
@@ -0,0 +1,166 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+#ifndef _LINUX_DM_ARRAY_H
+#define _LINUX_DM_ARRAY_H
+
+#include "dm-btree.h"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * The dm-array is a persistent version of an array. It packs the data
+ * more efficiently than a btree which will result in less disk space use,
+ * and a performance boost. The element get and set operations are still
+ * O(ln(n)), but with a much smaller constant.
+ *
+ * The value type structure is reused from the btree type to support proper
+ * reference counting of values.
+ *
+ * The arrays implicitly know their length, and bounds are checked for
+ * lookups and updated. It doesn't store this in an accessible place
+ * because it would waste a whole metadata block. Make sure you store the
+ * size along with the array root in your encompassing data.
+ *
+ * Array entries are indexed via an unsigned integer starting from zero.
+ * Arrays are not sparse; if you resize an array to have 'n' entries then
+ * 'n - 1' will be the last valid index.
+ *
+ * Typical use:
+ *
+ * a) initialise a dm_array_info structure. This describes the array
+ * values and ties it into a specific transaction manager. It holds no
+ * instance data; the same info can be used for many similar arrays if
+ * you wish.
+ *
+ * b) Get yourself a root. The root is the index of a block of data on the
+ * disk that holds a particular instance of an array. You may have a
+ * pre existing root in your metadata that you wish to use, or you may
+ * want to create a brand new, empty array with dm_array_empty().
+ *
+ * Like the other data structures in this library, dm_array objects are
+ * immutable between transactions. Update functions will return you the
+ * root for a _new_ array. If you've incremented the old root, via
+ * dm_tm_inc(), before calling the update function you may continue to use
+ * it in parallel with the new root.
+ *
+ * c) resize an array with dm_array_resize().
+ *
+ * d) Get a value from the array with dm_array_get_value().
+ *
+ * e) Set a value in the array with dm_array_set_value().
+ *
+ * f) Walk an array of values in index order with dm_array_walk(). More
+ * efficient than making many calls to dm_array_get_value().
+ *
+ * g) Destroy the array with dm_array_del(). This tells the transaction
+ * manager that you're no longer using this data structure so it can
+ * recycle it's blocks. (dm_array_dec() would be a better name for it,
+ * but del is in keeping with dm_btree_del()).
+ */
+
+/*
+ * Describes an array. Don't initialise this structure yourself, use the
+ * init function below.
+ */
+struct dm_array_info {
+ struct dm_transaction_manager *tm;
+ struct dm_btree_value_type value_type;
+ struct dm_btree_info btree_info;
+};
+
+/*
+ * Sets up a dm_array_info structure. You don't need to do anything with
+ * this structure when you finish using it.
+ *
+ * info - the structure being filled in.
+ * tm - the transaction manager that should supervise this structure.
+ * vt - describes the leaf values.
+ */
+void dm_array_info_init(struct dm_array_info *info,
+ struct dm_transaction_manager *tm,
+ struct dm_btree_value_type *vt);
+
+/*
+ * Create an empty, zero length array.
+ *
+ * info - describes the array
+ * root - on success this will be filled out with the root block
+ */
+int dm_array_empty(struct dm_array_info *info, dm_block_t *root);
+
+/*
+ * Resizes the array.
+ *
+ * info - describes the array
+ * root - the root block of the array on disk
+ * old_size - the caller is responsible for remembering the size of
+ * the array
+ * new_size - can be bigger or smaller than old_size
+ * value - if we're growing the array the new entries will have this value
+ * new_root - on success, points to the new root block
+ *
+ * If growing the inc function for 'value' will be called the appropriate
+ * number of times. So if the caller is holding a reference they may want
+ * to drop it.
+ */
+int dm_array_resize(struct dm_array_info *info, dm_block_t root,
+ uint32_t old_size, uint32_t new_size,
+ const void *value, dm_block_t *new_root)
+ __dm_written_to_disk(value);
+
+/*
+ * Frees a whole array. The value_type's decrement operation will be called
+ * for all values in the array
+ */
+int dm_array_del(struct dm_array_info *info, dm_block_t root);
+
+/*
+ * Lookup a value in the array
+ *
+ * info - describes the array
+ * root - root block of the array
+ * index - array index
+ * value - the value to be read. Will be in on-disk format of course.
+ *
+ * -ENODATA will be returned if the index is out of bounds.
+ */
+int dm_array_get_value(struct dm_array_info *info, dm_block_t root,
+ uint32_t index, void *value);
+
+/*
+ * Set an entry in the array.
+ *
+ * info - describes the array
+ * root - root block of the array
+ * index - array index
+ * value - value to be written to disk. Make sure you confirm the value is
+ * in on-disk format with__dm_bless_for_disk() before calling.
+ * new_root - the new root block
+ *
+ * The old value being overwritten will be decremented, the new value
+ * incremented.
+ *
+ * -ENODATA will be returned if the index is out of bounds.
+ */
+int dm_array_set_value(struct dm_array_info *info, dm_block_t root,
+ uint32_t index, const void *value, dm_block_t *new_root)
+ __dm_written_to_disk(value);
+
+/*
+ * Walk through all the entries in an array.
+ *
+ * info - describes the array
+ * root - root block of the array
+ * fn - called back for every element
+ * context - passed to the callback
+ */
+int dm_array_walk(struct dm_array_info *info, dm_block_t root,
+ int (*fn)(void *context, uint64_t key, void *leaf),
+ void *context);
+
+/*----------------------------------------------------------------*/
+
+#endif /* _LINUX_DM_ARRAY_H */
diff --git a/drivers/md/persistent-data/dm-bitset.c b/drivers/md/persistent-data/dm-bitset.c
new file mode 100644
index 0000000..cd9a86d
--- /dev/null
+++ b/drivers/md/persistent-data/dm-bitset.c
@@ -0,0 +1,163 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-bitset.h"
+#include "dm-transaction-manager.h"
+
+#include <linux/export.h>
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "bitset"
+#define BITS_PER_ARRAY_ENTRY 64
+
+/*----------------------------------------------------------------*/
+
+static struct dm_btree_value_type bitset_bvt = {
+ .context = NULL,
+ .size = sizeof(__le64),
+ .inc = NULL,
+ .dec = NULL,
+ .equal = NULL,
+};
+
+/*----------------------------------------------------------------*/
+
+void dm_disk_bitset_init(struct dm_transaction_manager *tm,
+ struct dm_disk_bitset *info)
+{
+ dm_array_info_init(&info->array_info, tm, &bitset_bvt);
+ info->current_index_set = false;
+}
+EXPORT_SYMBOL_GPL(dm_disk_bitset_init);
+
+int dm_bitset_empty(struct dm_disk_bitset *info, dm_block_t *root)
+{
+ return dm_array_empty(&info->array_info, root);
+}
+EXPORT_SYMBOL_GPL(dm_bitset_empty);
+
+int dm_bitset_resize(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t old_nr_entries, uint32_t new_nr_entries,
+ bool default_value, dm_block_t *new_root)
+{
+ uint32_t old_blocks = dm_div_up(old_nr_entries, BITS_PER_ARRAY_ENTRY);
+ uint32_t new_blocks = dm_div_up(new_nr_entries, BITS_PER_ARRAY_ENTRY);
+ __le64 value = default_value ? cpu_to_le64(~0) : cpu_to_le64(0);
+
+ __dm_bless_for_disk(&value);
+ return dm_array_resize(&info->array_info, root, old_blocks, new_blocks,
+ &value, new_root);
+}
+EXPORT_SYMBOL_GPL(dm_bitset_resize);
+
+int dm_bitset_del(struct dm_disk_bitset *info, dm_block_t root)
+{
+ return dm_array_del(&info->array_info, root);
+}
+EXPORT_SYMBOL_GPL(dm_bitset_del);
+
+int dm_bitset_flush(struct dm_disk_bitset *info, dm_block_t root,
+ dm_block_t *new_root)
+{
+ int r;
+ __le64 value;
+
+ if (!info->current_index_set)
+ return 0;
+
+ value = cpu_to_le64(info->current_bits);
+
+ __dm_bless_for_disk(&value);
+ r = dm_array_set_value(&info->array_info, root, info->current_index,
+ &value, new_root);
+ if (r)
+ return r;
+
+ info->current_index_set = false;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bitset_flush);
+
+static int read_bits(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t array_index)
+{
+ int r;
+ __le64 value;
+
+ r = dm_array_get_value(&info->array_info, root, array_index, &value);
+ if (r)
+ return r;
+
+ info->current_bits = le64_to_cpu(value);
+ info->current_index_set = true;
+ info->current_index = array_index;
+ return 0;
+}
+
+static int get_array_entry(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root)
+{
+ int r;
+ unsigned array_index = index / BITS_PER_ARRAY_ENTRY;
+
+ if (info->current_index_set) {
+ if (info->current_index == array_index)
+ return 0;
+
+ r = dm_bitset_flush(info, root, new_root);
+ if (r)
+ return r;
+ }
+
+ return read_bits(info, root, array_index);
+}
+
+int dm_bitset_set_bit(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root)
+{
+ int r;
+ unsigned b = index % BITS_PER_ARRAY_ENTRY;
+
+ r = get_array_entry(info, root, index, new_root);
+ if (r)
+ return r;
+
+ set_bit(b, (unsigned long *) &info->current_bits);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bitset_set_bit);
+
+int dm_bitset_clear_bit(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root)
+{
+ int r;
+ unsigned b = index % BITS_PER_ARRAY_ENTRY;
+
+ r = get_array_entry(info, root, index, new_root);
+ if (r)
+ return r;
+
+ clear_bit(b, (unsigned long *) &info->current_bits);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bitset_clear_bit);
+
+int dm_bitset_test_bit(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root, bool *result)
+{
+ int r;
+ unsigned b = index % BITS_PER_ARRAY_ENTRY;
+
+ r = get_array_entry(info, root, index, new_root);
+ if (r)
+ return r;
+
+ *result = test_bit(b, (unsigned long *) &info->current_bits);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bitset_test_bit);
+
+/*----------------------------------------------------------------*/
diff --git a/drivers/md/persistent-data/dm-bitset.h b/drivers/md/persistent-data/dm-bitset.h
new file mode 100644
index 0000000..e1b9bea
--- /dev/null
+++ b/drivers/md/persistent-data/dm-bitset.h
@@ -0,0 +1,165 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+#ifndef _LINUX_DM_BITSET_H
+#define _LINUX_DM_BITSET_H
+
+#include "dm-array.h"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * This bitset type is a thin wrapper round a dm_array of 64bit words. It
+ * uses a tiny, one word cache to reduce the number of array lookups and so
+ * increase performance.
+ *
+ * Like the dm-array that it's based on, the caller needs to keep track of
+ * the size of the bitset separately. The underlying dm-array implicitly
+ * knows how many words it's storing and will return -ENODATA if you try
+ * and access an out of bounds word. However, an out of bounds bit in the
+ * final word will _not_ be detected, you have been warned.
+ *
+ * Bits are indexed from zero.
+
+ * Typical use:
+ *
+ * a) Initialise a dm_disk_bitset structure with dm_disk_bitset_init().
+ * This describes the bitset and includes the cache. It's not called it
+ * dm_bitset_info in line with other data structures because it does
+ * include instance data.
+ *
+ * b) Get yourself a root. The root is the index of a block of data on the
+ * disk that holds a particular instance of an bitset. You may have a
+ * pre existing root in your metadata that you wish to use, or you may
+ * want to create a brand new, empty bitset with dm_bitset_empty().
+ *
+ * Like the other data structures in this library, dm_bitset objects are
+ * immutable between transactions. Update functions will return you the
+ * root for a _new_ array. If you've incremented the old root, via
+ * dm_tm_inc(), before calling the update function you may continue to use
+ * it in parallel with the new root.
+ *
+ * Even read operations may trigger the cache to be flushed and as such
+ * return a root for a new, updated bitset.
+ *
+ * c) resize a bitset with dm_bitset_resize().
+ *
+ * d) Set a bit with dm_bitset_set_bit().
+ *
+ * e) Clear a bit with dm_bitset_clear_bit().
+ *
+ * f) Test a bit with dm_bitset_test_bit().
+ *
+ * g) Flush all updates from the cache with dm_bitset_flush().
+ *
+ * h) Destroy the bitset with dm_bitset_del(). This tells the transaction
+ * manager that you're no longer using this data structure so it can
+ * recycle it's blocks. (dm_bitset_dec() would be a better name for it,
+ * but del is in keeping with dm_btree_del()).
+ */
+
+/*
+ * Opaque object. Unlike dm_array_info, you should have one of these per
+ * bitset. Initialise with dm_disk_bitset_init().
+ */
+struct dm_disk_bitset {
+ struct dm_array_info array_info;
+
+ uint32_t current_index;
+ uint64_t current_bits;
+
+ bool current_index_set:1;
+};
+
+/*
+ * Sets up a dm_disk_bitset structure. You don't need to do anything with
+ * this structure when you finish using it.
+ *
+ * tm - the transaction manager that should supervise this structure
+ * info - the structure being initialised
+ */
+void dm_disk_bitset_init(struct dm_transaction_manager *tm,
+ struct dm_disk_bitset *info);
+
+/*
+ * Create an empty, zero length bitset.
+ *
+ * info - describes the bitset
+ * new_root - on success, points to the new root block
+ */
+int dm_bitset_empty(struct dm_disk_bitset *info, dm_block_t *new_root);
+
+/*
+ * Resize the bitset.
+ *
+ * info - describes the bitset
+ * old_root - the root block of the array on disk
+ * old_nr_entries - the number of bits in the old bitset
+ * new_nr_entries - the number of bits you want in the new bitset
+ * default_value - the value for any new bits
+ * new_root - on success, points to the new root block
+ */
+int dm_bitset_resize(struct dm_disk_bitset *info, dm_block_t old_root,
+ uint32_t old_nr_entries, uint32_t new_nr_entries,
+ bool default_value, dm_block_t *new_root);
+
+/*
+ * Frees the bitset.
+ */
+int dm_bitset_del(struct dm_disk_bitset *info, dm_block_t root);
+
+/*
+ * Set a bit.
+ *
+ * info - describes the bitset
+ * root - the root block of the bitset
+ * index - the bit index
+ * new_root - on success, points to the new root block
+ *
+ * -ENODATA will be returned if the index is out of bounds.
+ */
+int dm_bitset_set_bit(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root);
+
+/*
+ * Clears a bit.
+ *
+ * info - describes the bitset
+ * root - the root block of the bitset
+ * index - the bit index
+ * new_root - on success, points to the new root block
+ *
+ * -ENODATA will be returned if the index is out of bounds.
+ */
+int dm_bitset_clear_bit(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root);
+
+/*
+ * Tests a bit.
+ *
+ * info - describes the bitset
+ * root - the root block of the bitset
+ * index - the bit index
+ * new_root - on success, points to the new root block (cached values may have been written)
+ * result - the bit value you're after
+ *
+ * -ENODATA will be returned if the index is out of bounds.
+ */
+int dm_bitset_test_bit(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root, bool *result);
+
+/*
+ * Flush any cached changes to disk.
+ *
+ * info - describes the bitset
+ * root - the root block of the bitset
+ * new_root - on success, points to the new root block
+ */
+int dm_bitset_flush(struct dm_disk_bitset *info, dm_block_t root,
+ dm_block_t *new_root);
+
+/*----------------------------------------------------------------*/
+
+#endif /* _LINUX_DM_BITSET_H */
diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
index 28c3ed0..81b5138 100644
--- a/drivers/md/persistent-data/dm-block-manager.c
+++ b/drivers/md/persistent-data/dm-block-manager.c
@@ -613,6 +613,7 @@ int dm_bm_flush_and_unlock(struct dm_block_manager *bm,
return dm_bufio_write_dirty_buffers(bm->bufio);
}
+EXPORT_SYMBOL_GPL(dm_bm_flush_and_unlock);
void dm_bm_set_read_only(struct dm_block_manager *bm)
{
diff --git a/drivers/md/persistent-data/dm-btree-internal.h b/drivers/md/persistent-data/dm-btree-internal.h
index accbb05..37d367b 100644
--- a/drivers/md/persistent-data/dm-btree-internal.h
+++ b/drivers/md/persistent-data/dm-btree-internal.h
@@ -64,6 +64,7 @@ struct ro_spine {
void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info);
int exit_ro_spine(struct ro_spine *s);
int ro_step(struct ro_spine *s, dm_block_t new_child);
+void ro_pop(struct ro_spine *s);
struct btree_node *ro_node(struct ro_spine *s);
struct shadow_spine {
diff --git a/drivers/md/persistent-data/dm-btree-spine.c b/drivers/md/persistent-data/dm-btree-spine.c
index f199a0c..cf9fd67 100644
--- a/drivers/md/persistent-data/dm-btree-spine.c
+++ b/drivers/md/persistent-data/dm-btree-spine.c
@@ -164,6 +164,13 @@ int ro_step(struct ro_spine *s, dm_block_t new_child)
return r;
}
+void ro_pop(struct ro_spine *s)
+{
+ BUG_ON(!s->count);
+ --s->count;
+ unlock_block(s->info, s->nodes[s->count]);
+}
+
struct btree_node *ro_node(struct ro_spine *s)
{
struct dm_block *block;
diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c
index 4caf669..3586542 100644
--- a/drivers/md/persistent-data/dm-btree.c
+++ b/drivers/md/persistent-data/dm-btree.c
@@ -807,3 +807,55 @@ int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
return r ? r : count;
}
EXPORT_SYMBOL_GPL(dm_btree_find_highest_key);
+
+/*
+ * FIXME: We shouldn't use a recursive algorithm when we have limited stack
+ * space. Also this only works for single level trees.
+ */
+static int walk_node(struct ro_spine *s, dm_block_t block,
+ int (*fn)(void *context, uint64_t *keys, void *leaf),
+ void *context)
+{
+ int r;
+ unsigned i, nr;
+ struct btree_node *n;
+ uint64_t keys;
+
+ r = ro_step(s, block);
+ n = ro_node(s);
+
+ nr = le32_to_cpu(n->header.nr_entries);
+ for (i = 0; i < nr; i++) {
+ if (le32_to_cpu(n->header.flags) & INTERNAL_NODE) {
+ r = walk_node(s, value64(n, i), fn, context);
+ if (r)
+ goto out;
+ } else {
+ keys = le64_to_cpu(*key_ptr(n, i));
+ r = fn(context, &keys, value_ptr(n, i));
+ if (r)
+ goto out;
+ }
+ }
+
+out:
+ ro_pop(s);
+ return r;
+}
+
+int dm_btree_walk(struct dm_btree_info *info, dm_block_t root,
+ int (*fn)(void *context, uint64_t *keys, void *leaf),
+ void *context)
+{
+ int r;
+ struct ro_spine spine;
+
+ BUG_ON(info->levels > 1);
+
+ init_ro_spine(&spine, info);
+ r = walk_node(&spine, root, fn, context);
+ exit_ro_spine(&spine);
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_btree_walk);
diff --git a/drivers/md/persistent-data/dm-btree.h b/drivers/md/persistent-data/dm-btree.h
index a2cd5044..8672d15 100644
--- a/drivers/md/persistent-data/dm-btree.h
+++ b/drivers/md/persistent-data/dm-btree.h
@@ -58,21 +58,21 @@ struct dm_btree_value_type {
* somewhere.) This method is _not_ called for insertion of a new
* value: It is assumed the ref count is already 1.
*/
- void (*inc)(void *context, void *value);
+ void (*inc)(void *context, const void *value);
/*
* This value is being deleted. The btree takes care of freeing
* the memory pointed to by @value. Often the del function just
* needs to decrement a reference count somewhere.
*/
- void (*dec)(void *context, void *value);
+ void (*dec)(void *context, const void *value);
/*
* A test for equality between two values. When a value is
* overwritten with a new one, the old one has the dec method
* called _unless_ the new and old value are deemed equal.
*/
- int (*equal)(void *context, void *value1, void *value2);
+ int (*equal)(void *context, const void *value1, const void *value2);
};
/*
@@ -142,4 +142,13 @@ int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
uint64_t *result_keys);
+/*
+ * Iterate through the a btree, calling fn() on each entry.
+ * It only works for single level trees and is internally recursive, so
+ * monitor stack usage carefully.
+ */
+int dm_btree_walk(struct dm_btree_info *info, dm_block_t root,
+ int (*fn)(void *context, uint64_t *keys, void *leaf),
+ void *context);
+
#endif /* _LINUX_DM_BTREE_H */
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index bf6afa2..1e483fa 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -68,8 +68,8 @@ typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
typedef int (*dm_preresume_fn) (struct dm_target *ti);
typedef void (*dm_resume_fn) (struct dm_target *ti);
-typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
- unsigned status_flags, char *result, unsigned maxlen);
+typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
+ unsigned status_flags, char *result, unsigned maxlen);
typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
@@ -175,6 +175,14 @@ struct target_type {
#define DM_TARGET_IMMUTABLE 0x00000004
#define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
+/*
+ * Some targets need to be sent the same WRITE bio severals times so
+ * that they can send copies of it to different devices. This function
+ * examines any supplied bio and returns the number of copies of it the
+ * target requires.
+ */
+typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio);
+
struct dm_target {
struct dm_table *table;
struct target_type *type;
@@ -187,26 +195,26 @@ struct dm_target {
uint32_t max_io_len;
/*
- * A number of zero-length barrier requests that will be submitted
+ * A number of zero-length barrier bios that will be submitted
* to the target for the purpose of flushing cache.
*
- * The request number can be accessed with dm_bio_get_target_request_nr.
- * It is a responsibility of the target driver to remap these requests
+ * The bio number can be accessed with dm_bio_get_target_bio_nr.
+ * It is a responsibility of the target driver to remap these bios
* to the real underlying devices.
*/
- unsigned num_flush_requests;
+ unsigned num_flush_bios;
/*
- * The number of discard requests that will be submitted to the target.
- * The request number can be accessed with dm_bio_get_target_request_nr.
+ * The number of discard bios that will be submitted to the target.
+ * The bio number can be accessed with dm_bio_get_target_bio_nr.
*/
- unsigned num_discard_requests;
+ unsigned num_discard_bios;
/*
- * The number of WRITE SAME requests that will be submitted to the target.
- * The request number can be accessed with dm_bio_get_target_request_nr.
+ * The number of WRITE SAME bios that will be submitted to the target.
+ * The bio number can be accessed with dm_bio_get_target_bio_nr.
*/
- unsigned num_write_same_requests;
+ unsigned num_write_same_bios;
/*
* The minimum number of extra bytes allocated in each bio for the
@@ -214,6 +222,13 @@ struct dm_target {
*/
unsigned per_bio_data_size;
+ /*
+ * If defined, this function is called to find out how many
+ * duplicate bios should be sent to the target when writing
+ * data.
+ */
+ dm_num_write_bios_fn num_write_bios;
+
/* target specific data */
void *private;
@@ -233,10 +248,10 @@ struct dm_target {
bool discards_supported:1;
/*
- * Set if the target required discard request to be split
+ * Set if the target required discard bios to be split
* on max_io_len boundary.
*/
- bool split_discard_requests:1;
+ bool split_discard_bios:1;
/*
* Set if this target does not return zeroes on discarded blocks.
@@ -261,7 +276,7 @@ struct dm_target_io {
struct dm_io *io;
struct dm_target *ti;
union map_info info;
- unsigned target_request_nr;
+ unsigned target_bio_nr;
struct bio clone;
};
@@ -275,9 +290,9 @@ static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
}
-static inline unsigned dm_bio_get_target_request_nr(const struct bio *bio)
+static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
{
- return container_of(bio, struct dm_target_io, clone)->target_request_nr;
+ return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
}
int dm_register_target(struct target_type *t);
diff --git a/include/linux/dm-kcopyd.h b/include/linux/dm-kcopyd.h
index 47d9d37..f486d63 100644
--- a/include/linux/dm-kcopyd.h
+++ b/include/linux/dm-kcopyd.h
@@ -21,11 +21,34 @@
#define DM_KCOPYD_IGNORE_ERROR 1
+struct dm_kcopyd_throttle {
+ unsigned throttle;
+ unsigned num_io_jobs;
+ unsigned io_period;
+ unsigned total_period;
+ unsigned last_jiffies;
+};
+
+/*
+ * kcopyd clients that want to support throttling must pass an initialised
+ * dm_kcopyd_throttle struct into dm_kcopyd_client_create().
+ * Two or more clients may share the same instance of this struct between
+ * them if they wish to be throttled as a group.
+ *
+ * This macro also creates a corresponding module parameter to configure
+ * the amount of throttling.
+ */
+#define DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(name, description) \
+static struct dm_kcopyd_throttle dm_kcopyd_throttle = { 100, 0, 0, 0, 0 }; \
+module_param_named(name, dm_kcopyd_throttle.throttle, uint, 0644); \
+MODULE_PARM_DESC(name, description)
+
/*
* To use kcopyd you must first create a dm_kcopyd_client object.
+ * throttle can be NULL if you don't want any throttling.
*/
struct dm_kcopyd_client;
-struct dm_kcopyd_client *dm_kcopyd_client_create(void);
+struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle);
void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc);
/*
diff --git a/include/uapi/linux/dm-ioctl.h b/include/uapi/linux/dm-ioctl.h
index 539b179..7e75b6f 100644
--- a/include/uapi/linux/dm-ioctl.h
+++ b/include/uapi/linux/dm-ioctl.h
@@ -267,9 +267,9 @@ enum {
#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
#define DM_VERSION_MAJOR 4
-#define DM_VERSION_MINOR 23
-#define DM_VERSION_PATCHLEVEL 1
-#define DM_VERSION_EXTRA "-ioctl (2012-12-18)"
+#define DM_VERSION_MINOR 24
+#define DM_VERSION_PATCHLEVEL 0
+#define DM_VERSION_EXTRA "-ioctl (2013-01-15)"
/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */
@@ -336,4 +336,9 @@ enum {
*/
#define DM_SECURE_DATA_FLAG (1 << 15) /* In */
+/*
+ * If set, a message generated output data.
+ */
+#define DM_DATA_OUT_FLAG (1 << 16) /* Out */
+
#endif /* _LINUX_DM_IOCTL_H */