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-rw-r--r--Documentation/device-mapper/snapshot.txt60
-rw-r--r--drivers/md/dm-crypt.c207
-rw-r--r--drivers/md/dm-exception-store.c33
-rw-r--r--drivers/md/dm-exception-store.h62
-rw-r--r--drivers/md/dm-io.c120
-rw-r--r--drivers/md/dm-ioctl.c123
-rw-r--r--drivers/md/dm-kcopyd.c5
-rw-r--r--drivers/md/dm-log.c77
-rw-r--r--drivers/md/dm-mpath.c95
-rw-r--r--drivers/md/dm-raid1.c219
-rw-r--r--drivers/md/dm-region-hash.c31
-rw-r--r--drivers/md/dm-snap-persistent.c195
-rw-r--r--drivers/md/dm-snap-transient.c24
-rw-r--r--drivers/md/dm-snap.c1279
-rw-r--r--drivers/md/dm-sysfs.c10
-rw-r--r--drivers/md/dm-table.c3
-rw-r--r--drivers/md/dm-uevent.c9
-rw-r--r--drivers/md/dm.c643
-rw-r--r--drivers/md/dm.h13
-rw-r--r--include/linux/device-mapper.h8
-rw-r--r--include/linux/dm-dirty-log.h6
-rw-r--r--include/linux/dm-ioctl.h13
-rw-r--r--include/linux/dm-region-hash.h3
23 files changed, 2349 insertions, 889 deletions
diff --git a/Documentation/device-mapper/snapshot.txt b/Documentation/device-mapper/snapshot.txt
index a5009c8..e3a77b2 100644
--- a/Documentation/device-mapper/snapshot.txt
+++ b/Documentation/device-mapper/snapshot.txt
@@ -8,13 +8,19 @@ the block device which are also writable without interfering with the
original content;
*) To create device "forks", i.e. multiple different versions of the
same data stream.
+*) To merge a snapshot of a block device back into the snapshot's origin
+device.
+In the first two cases, dm copies only the chunks of data that get
+changed and uses a separate copy-on-write (COW) block device for
+storage.
-In both cases, dm copies only the chunks of data that get changed and
-uses a separate copy-on-write (COW) block device for storage.
+For snapshot merge the contents of the COW storage are merged back into
+the origin device.
-There are two dm targets available: snapshot and snapshot-origin.
+There are three dm targets available:
+snapshot, snapshot-origin, and snapshot-merge.
*) snapshot-origin <origin>
@@ -40,8 +46,25 @@ The difference is that for transient snapshots less metadata must be
saved on disk - they can be kept in memory by the kernel.
-How this is used by LVM2
-========================
+* snapshot-merge <origin> <COW device> <persistent> <chunksize>
+
+takes the same table arguments as the snapshot target except it only
+works with persistent snapshots. This target assumes the role of the
+"snapshot-origin" target and must not be loaded if the "snapshot-origin"
+is still present for <origin>.
+
+Creates a merging snapshot that takes control of the changed chunks
+stored in the <COW device> of an existing snapshot, through a handover
+procedure, and merges these chunks back into the <origin>. Once merging
+has started (in the background) the <origin> may be opened and the merge
+will continue while I/O is flowing to it. Changes to the <origin> are
+deferred until the merging snapshot's corresponding chunk(s) have been
+merged. Once merging has started the snapshot device, associated with
+the "snapshot" target, will return -EIO when accessed.
+
+
+How snapshot is used by LVM2
+============================
When you create the first LVM2 snapshot of a volume, four dm devices are used:
1) a device containing the original mapping table of the source volume;
@@ -72,3 +95,30 @@ brw------- 1 root root 254, 12 29 ago 18:15 /dev/mapper/volumeGroup-snap-cow
brw------- 1 root root 254, 13 29 ago 18:15 /dev/mapper/volumeGroup-snap
brw------- 1 root root 254, 10 29 ago 18:14 /dev/mapper/volumeGroup-base
+
+How snapshot-merge is used by LVM2
+==================================
+A merging snapshot assumes the role of the "snapshot-origin" while
+merging. As such the "snapshot-origin" is replaced with
+"snapshot-merge". The "-real" device is not changed and the "-cow"
+device is renamed to <origin name>-cow to aid LVM2's cleanup of the
+merging snapshot after it completes. The "snapshot" that hands over its
+COW device to the "snapshot-merge" is deactivated (unless using lvchange
+--refresh); but if it is left active it will simply return I/O errors.
+
+A snapshot will merge into its origin with the following command:
+
+lvconvert --merge volumeGroup/snap
+
+we'll now have this situation:
+
+# dmsetup table|grep volumeGroup
+
+volumeGroup-base-real: 0 2097152 linear 8:19 384
+volumeGroup-base-cow: 0 204800 linear 8:19 2097536
+volumeGroup-base: 0 2097152 snapshot-merge 254:11 254:12 P 16
+
+# ls -lL /dev/mapper/volumeGroup-*
+brw------- 1 root root 254, 11 29 ago 18:15 /dev/mapper/volumeGroup-base-real
+brw------- 1 root root 254, 12 29 ago 18:16 /dev/mapper/volumeGroup-base-cow
+brw------- 1 root root 254, 10 29 ago 18:16 /dev/mapper/volumeGroup-base
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index e412980..a936372 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1,7 +1,7 @@
/*
* Copyright (C) 2003 Christophe Saout <christophe@saout.de>
* Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
- * Copyright (C) 2006-2008 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2006-2009 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
@@ -71,10 +71,21 @@ struct crypt_iv_operations {
int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
const char *opts);
void (*dtr)(struct crypt_config *cc);
- const char *(*status)(struct crypt_config *cc);
+ int (*init)(struct crypt_config *cc);
+ int (*wipe)(struct crypt_config *cc);
int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
};
+struct iv_essiv_private {
+ struct crypto_cipher *tfm;
+ struct crypto_hash *hash_tfm;
+ u8 *salt;
+};
+
+struct iv_benbi_private {
+ int shift;
+};
+
/*
* Crypt: maps a linear range of a block device
* and encrypts / decrypts at the same time.
@@ -102,8 +113,8 @@ struct crypt_config {
struct crypt_iv_operations *iv_gen_ops;
char *iv_mode;
union {
- struct crypto_cipher *essiv_tfm;
- int benbi_shift;
+ struct iv_essiv_private essiv;
+ struct iv_benbi_private benbi;
} iv_gen_private;
sector_t iv_offset;
unsigned int iv_size;
@@ -147,6 +158,9 @@ static void kcryptd_queue_crypt(struct dm_crypt_io *io);
* plain: the initial vector is the 32-bit little-endian version of the sector
* number, padded with zeros if necessary.
*
+ * plain64: the initial vector is the 64-bit little-endian version of the sector
+ * number, padded with zeros if necessary.
+ *
* essiv: "encrypted sector|salt initial vector", the sector number is
* encrypted with the bulk cipher using a salt as key. The salt
* should be derived from the bulk cipher's key via hashing.
@@ -169,88 +183,123 @@ static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
return 0;
}
-static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
- const char *opts)
+static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
+ sector_t sector)
{
- struct crypto_cipher *essiv_tfm;
- struct crypto_hash *hash_tfm;
+ memset(iv, 0, cc->iv_size);
+ *(u64 *)iv = cpu_to_le64(sector);
+
+ return 0;
+}
+
+/* Initialise ESSIV - compute salt but no local memory allocations */
+static int crypt_iv_essiv_init(struct crypt_config *cc)
+{
+ struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
struct hash_desc desc;
struct scatterlist sg;
- unsigned int saltsize;
- u8 *salt;
int err;
- if (opts == NULL) {
+ sg_init_one(&sg, cc->key, cc->key_size);
+ desc.tfm = essiv->hash_tfm;
+ desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+ err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt);
+ if (err)
+ return err;
+
+ return crypto_cipher_setkey(essiv->tfm, essiv->salt,
+ crypto_hash_digestsize(essiv->hash_tfm));
+}
+
+/* Wipe salt and reset key derived from volume key */
+static int crypt_iv_essiv_wipe(struct crypt_config *cc)
+{
+ struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
+ unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm);
+
+ memset(essiv->salt, 0, salt_size);
+
+ return crypto_cipher_setkey(essiv->tfm, essiv->salt, salt_size);
+}
+
+static void crypt_iv_essiv_dtr(struct crypt_config *cc)
+{
+ struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
+
+ crypto_free_cipher(essiv->tfm);
+ essiv->tfm = NULL;
+
+ crypto_free_hash(essiv->hash_tfm);
+ essiv->hash_tfm = NULL;
+
+ kzfree(essiv->salt);
+ essiv->salt = NULL;
+}
+
+static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
+ const char *opts)
+{
+ struct crypto_cipher *essiv_tfm = NULL;
+ struct crypto_hash *hash_tfm = NULL;
+ u8 *salt = NULL;
+ int err;
+
+ if (!opts) {
ti->error = "Digest algorithm missing for ESSIV mode";
return -EINVAL;
}
- /* Hash the cipher key with the given hash algorithm */
+ /* Allocate hash algorithm */
hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(hash_tfm)) {
ti->error = "Error initializing ESSIV hash";
- return PTR_ERR(hash_tfm);
+ err = PTR_ERR(hash_tfm);
+ goto bad;
}
- saltsize = crypto_hash_digestsize(hash_tfm);
- salt = kmalloc(saltsize, GFP_KERNEL);
- if (salt == NULL) {
+ salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL);
+ if (!salt) {
ti->error = "Error kmallocing salt storage in ESSIV";
- crypto_free_hash(hash_tfm);
- return -ENOMEM;
+ err = -ENOMEM;
+ goto bad;
}
- sg_init_one(&sg, cc->key, cc->key_size);
- desc.tfm = hash_tfm;
- desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
- err = crypto_hash_digest(&desc, &sg, cc->key_size, salt);
- crypto_free_hash(hash_tfm);
-
- if (err) {
- ti->error = "Error calculating hash in ESSIV";
- kfree(salt);
- return err;
- }
-
- /* Setup the essiv_tfm with the given salt */
+ /* Allocate essiv_tfm */
essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(essiv_tfm)) {
ti->error = "Error allocating crypto tfm for ESSIV";
- kfree(salt);
- return PTR_ERR(essiv_tfm);
+ err = PTR_ERR(essiv_tfm);
+ goto bad;
}
if (crypto_cipher_blocksize(essiv_tfm) !=
crypto_ablkcipher_ivsize(cc->tfm)) {
ti->error = "Block size of ESSIV cipher does "
"not match IV size of block cipher";
- crypto_free_cipher(essiv_tfm);
- kfree(salt);
- return -EINVAL;
+ err = -EINVAL;
+ goto bad;
}
- err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
- if (err) {
- ti->error = "Failed to set key for ESSIV cipher";
- crypto_free_cipher(essiv_tfm);
- kfree(salt);
- return err;
- }
- kfree(salt);
- cc->iv_gen_private.essiv_tfm = essiv_tfm;
+ cc->iv_gen_private.essiv.salt = salt;
+ cc->iv_gen_private.essiv.tfm = essiv_tfm;
+ cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
+
return 0;
-}
-static void crypt_iv_essiv_dtr(struct crypt_config *cc)
-{
- crypto_free_cipher(cc->iv_gen_private.essiv_tfm);
- cc->iv_gen_private.essiv_tfm = NULL;
+bad:
+ if (essiv_tfm && !IS_ERR(essiv_tfm))
+ crypto_free_cipher(essiv_tfm);
+ if (hash_tfm && !IS_ERR(hash_tfm))
+ crypto_free_hash(hash_tfm);
+ kfree(salt);
+ return err;
}
static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
{
memset(iv, 0, cc->iv_size);
*(u64 *)iv = cpu_to_le64(sector);
- crypto_cipher_encrypt_one(cc->iv_gen_private.essiv_tfm, iv, iv);
+ crypto_cipher_encrypt_one(cc->iv_gen_private.essiv.tfm, iv, iv);
return 0;
}
@@ -273,7 +322,7 @@ static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
return -EINVAL;
}
- cc->iv_gen_private.benbi_shift = 9 - log;
+ cc->iv_gen_private.benbi.shift = 9 - log;
return 0;
}
@@ -288,7 +337,7 @@ static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
- val = cpu_to_be64(((u64)sector << cc->iv_gen_private.benbi_shift) + 1);
+ val = cpu_to_be64(((u64)sector << cc->iv_gen_private.benbi.shift) + 1);
put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
return 0;
@@ -305,9 +354,15 @@ static struct crypt_iv_operations crypt_iv_plain_ops = {
.generator = crypt_iv_plain_gen
};
+static struct crypt_iv_operations crypt_iv_plain64_ops = {
+ .generator = crypt_iv_plain64_gen
+};
+
static struct crypt_iv_operations crypt_iv_essiv_ops = {
.ctr = crypt_iv_essiv_ctr,
.dtr = crypt_iv_essiv_dtr,
+ .init = crypt_iv_essiv_init,
+ .wipe = crypt_iv_essiv_wipe,
.generator = crypt_iv_essiv_gen
};
@@ -934,14 +989,14 @@ static int crypt_set_key(struct crypt_config *cc, char *key)
set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
- return 0;
+ return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size);
}
static int crypt_wipe_key(struct crypt_config *cc)
{
clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
memset(&cc->key, 0, cc->key_size * sizeof(u8));
- return 0;
+ return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size);
}
/*
@@ -983,11 +1038,6 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
return -ENOMEM;
}
- if (crypt_set_key(cc, argv[1])) {
- ti->error = "Error decoding key";
- goto bad_cipher;
- }
-
/* Compatibility mode for old dm-crypt cipher strings */
if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
chainmode = "cbc";
@@ -1015,6 +1065,11 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
strcpy(cc->chainmode, chainmode);
cc->tfm = tfm;
+ if (crypt_set_key(cc, argv[1]) < 0) {
+ ti->error = "Error decoding and setting key";
+ goto bad_ivmode;
+ }
+
/*
* Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
* See comments at iv code
@@ -1024,6 +1079,8 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
cc->iv_gen_ops = NULL;
else if (strcmp(ivmode, "plain") == 0)
cc->iv_gen_ops = &crypt_iv_plain_ops;
+ else if (strcmp(ivmode, "plain64") == 0)
+ cc->iv_gen_ops = &crypt_iv_plain64_ops;
else if (strcmp(ivmode, "essiv") == 0)
cc->iv_gen_ops = &crypt_iv_essiv_ops;
else if (strcmp(ivmode, "benbi") == 0)
@@ -1039,6 +1096,12 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
goto bad_ivmode;
+ if (cc->iv_gen_ops && cc->iv_gen_ops->init &&
+ cc->iv_gen_ops->init(cc) < 0) {
+ ti->error = "Error initialising IV";
+ goto bad_slab_pool;
+ }
+
cc->iv_size = crypto_ablkcipher_ivsize(tfm);
if (cc->iv_size)
/* at least a 64 bit sector number should fit in our buffer */
@@ -1085,11 +1148,6 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad_bs;
}
- if (crypto_ablkcipher_setkey(tfm, cc->key, key_size) < 0) {
- ti->error = "Error setting key";
- goto bad_device;
- }
-
if (sscanf(argv[2], "%llu", &tmpll) != 1) {
ti->error = "Invalid iv_offset sector";
goto bad_device;
@@ -1278,6 +1336,7 @@ static void crypt_resume(struct dm_target *ti)
static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
{
struct crypt_config *cc = ti->private;
+ int ret = -EINVAL;
if (argc < 2)
goto error;
@@ -1287,10 +1346,22 @@ static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
DMWARN("not suspended during key manipulation.");
return -EINVAL;
}
- if (argc == 3 && !strnicmp(argv[1], MESG_STR("set")))
- return crypt_set_key(cc, argv[2]);
- if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe")))
+ if (argc == 3 && !strnicmp(argv[1], MESG_STR("set"))) {
+ ret = crypt_set_key(cc, argv[2]);
+ if (ret)
+ return ret;
+ if (cc->iv_gen_ops && cc->iv_gen_ops->init)
+ ret = cc->iv_gen_ops->init(cc);
+ return ret;
+ }
+ if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe"))) {
+ if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
+ ret = cc->iv_gen_ops->wipe(cc);
+ if (ret)
+ return ret;
+ }
return crypt_wipe_key(cc);
+ }
}
error:
diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c
index 7dbe652..2b7907b 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -172,7 +172,8 @@ int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
}
/* Validate the chunk size against the device block size */
- if (chunk_size % (bdev_logical_block_size(store->cow->bdev) >> 9)) {
+ if (chunk_size %
+ (bdev_logical_block_size(dm_snap_cow(store->snap)->bdev) >> 9)) {
*error = "Chunk size is not a multiple of device blocksize";
return -EINVAL;
}
@@ -190,6 +191,7 @@ int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
}
int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
+ struct dm_snapshot *snap,
unsigned *args_used,
struct dm_exception_store **store)
{
@@ -198,7 +200,7 @@ int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
struct dm_exception_store *tmp_store;
char persistent;
- if (argc < 3) {
+ if (argc < 2) {
ti->error = "Insufficient exception store arguments";
return -EINVAL;
}
@@ -209,14 +211,15 @@ int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
return -ENOMEM;
}
- persistent = toupper(*argv[1]);
+ persistent = toupper(*argv[0]);
if (persistent == 'P')
type = get_type("P");
else if (persistent == 'N')
type = get_type("N");
else {
ti->error = "Persistent flag is not P or N";
- return -EINVAL;
+ r = -EINVAL;
+ goto bad_type;
}
if (!type) {
@@ -226,32 +229,23 @@ int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
}
tmp_store->type = type;
- tmp_store->ti = ti;
-
- r = dm_get_device(ti, argv[0], 0, 0,
- FMODE_READ | FMODE_WRITE, &tmp_store->cow);
- if (r) {
- ti->error = "Cannot get COW device";
- goto bad_cow;
- }
+ tmp_store->snap = snap;
- r = set_chunk_size(tmp_store, argv[2], &ti->error);
+ r = set_chunk_size(tmp_store, argv[1], &ti->error);
if (r)
- goto bad_ctr;
+ goto bad;
r = type->ctr(tmp_store, 0, NULL);
if (r) {
ti->error = "Exception store type constructor failed";
- goto bad_ctr;
+ goto bad;
}
- *args_used = 3;
+ *args_used = 2;
*store = tmp_store;
return 0;
-bad_ctr:
- dm_put_device(ti, tmp_store->cow);
-bad_cow:
+bad:
put_type(type);
bad_type:
kfree(tmp_store);
@@ -262,7 +256,6 @@ EXPORT_SYMBOL(dm_exception_store_create);
void dm_exception_store_destroy(struct dm_exception_store *store)
{
store->type->dtr(store);
- dm_put_device(store->ti, store->cow);
put_type(store->type);
kfree(store);
}
diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h
index 8a223a4..e8dfa06 100644
--- a/drivers/md/dm-exception-store.h
+++ b/drivers/md/dm-exception-store.h
@@ -26,7 +26,7 @@ typedef sector_t chunk_t;
* of chunks that follow contiguously. Remaining bits hold the number of the
* chunk within the device.
*/
-struct dm_snap_exception {
+struct dm_exception {
struct list_head hash_list;
chunk_t old_chunk;
@@ -64,17 +64,34 @@ struct dm_exception_store_type {
* Find somewhere to store the next exception.
*/
int (*prepare_exception) (struct dm_exception_store *store,
- struct dm_snap_exception *e);
+ struct dm_exception *e);
/*
* Update the metadata with this exception.
*/
void (*commit_exception) (struct dm_exception_store *store,
- struct dm_snap_exception *e,
+ struct dm_exception *e,
void (*callback) (void *, int success),
void *callback_context);
/*
+ * Returns 0 if the exception store is empty.
+ *
+ * If there are exceptions still to be merged, sets
+ * *last_old_chunk and *last_new_chunk to the most recent
+ * still-to-be-merged chunk and returns the number of
+ * consecutive previous ones.
+ */
+ int (*prepare_merge) (struct dm_exception_store *store,
+ chunk_t *last_old_chunk, chunk_t *last_new_chunk);
+
+ /*
+ * Clear the last n exceptions.
+ * nr_merged must be <= the value returned by prepare_merge.
+ */
+ int (*commit_merge) (struct dm_exception_store *store, int nr_merged);
+
+ /*
* The snapshot is invalid, note this in the metadata.
*/
void (*drop_snapshot) (struct dm_exception_store *store);
@@ -86,19 +103,19 @@ struct dm_exception_store_type {
/*
* Return how full the snapshot is.
*/
- void (*fraction_full) (struct dm_exception_store *store,
- sector_t *numerator,
- sector_t *denominator);
+ void (*usage) (struct dm_exception_store *store,
+ sector_t *total_sectors, sector_t *sectors_allocated,
+ sector_t *metadata_sectors);
/* For internal device-mapper use only. */
struct list_head list;
};
+struct dm_snapshot;
+
struct dm_exception_store {
struct dm_exception_store_type *type;
- struct dm_target *ti;
-
- struct dm_dev *cow;
+ struct dm_snapshot *snap;
/* Size of data blocks saved - must be a power of 2 */
unsigned chunk_size;
@@ -109,6 +126,11 @@ struct dm_exception_store {
};
/*
+ * Obtain the cow device used by a given snapshot.
+ */
+struct dm_dev *dm_snap_cow(struct dm_snapshot *snap);
+
+/*
* Funtions to manipulate consecutive chunks
*/
# if defined(CONFIG_LBDAF) || (BITS_PER_LONG == 64)
@@ -120,18 +142,25 @@ static inline chunk_t dm_chunk_number(chunk_t chunk)
return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL);
}
-static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
+static inline unsigned dm_consecutive_chunk_count(struct dm_exception *e)
{
return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
}
-static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
+static inline void dm_consecutive_chunk_count_inc(struct dm_exception *e)
{
e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS);
BUG_ON(!dm_consecutive_chunk_count(e));
}
+static inline void dm_consecutive_chunk_count_dec(struct dm_exception *e)
+{
+ BUG_ON(!dm_consecutive_chunk_count(e));
+
+ e->new_chunk -= (1ULL << DM_CHUNK_NUMBER_BITS);
+}
+
# else
# define DM_CHUNK_CONSECUTIVE_BITS 0
@@ -140,12 +169,16 @@ static inline chunk_t dm_chunk_number(chunk_t chunk)
return chunk;
}
-static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
+static inline unsigned dm_consecutive_chunk_count(struct dm_exception *e)
{
return 0;
}
-static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
+static inline void dm_consecutive_chunk_count_inc(struct dm_exception *e)
+{
+}
+
+static inline void dm_consecutive_chunk_count_dec(struct dm_exception *e)
{
}
@@ -162,7 +195,7 @@ static inline sector_t get_dev_size(struct block_device *bdev)
static inline chunk_t sector_to_chunk(struct dm_exception_store *store,
sector_t sector)
{
- return (sector & ~store->chunk_mask) >> store->chunk_shift;
+ return sector >> store->chunk_shift;
}
int dm_exception_store_type_register(struct dm_exception_store_type *type);
@@ -173,6 +206,7 @@ int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
char **error);
int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
+ struct dm_snapshot *snap,
unsigned *args_used,
struct dm_exception_store **store);
void dm_exception_store_destroy(struct dm_exception_store *store);
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 3a2e6a2..10f457c 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -5,6 +5,8 @@
* This file is released under the GPL.
*/
+#include "dm.h"
+
#include <linux/device-mapper.h>
#include <linux/bio.h>
@@ -14,12 +16,19 @@
#include <linux/slab.h>
#include <linux/dm-io.h>
+#define DM_MSG_PREFIX "io"
+
+#define DM_IO_MAX_REGIONS BITS_PER_LONG
+
struct dm_io_client {
mempool_t *pool;
struct bio_set *bios;
};
-/* FIXME: can we shrink this ? */
+/*
+ * Aligning 'struct io' reduces the number of bits required to store
+ * its address. Refer to store_io_and_region_in_bio() below.
+ */
struct io {
unsigned long error_bits;
unsigned long eopnotsupp_bits;
@@ -28,7 +37,9 @@ struct io {
struct dm_io_client *client;
io_notify_fn callback;
void *context;
-};
+} __attribute__((aligned(DM_IO_MAX_REGIONS)));
+
+static struct kmem_cache *_dm_io_cache;
/*
* io contexts are only dynamically allocated for asynchronous
@@ -53,7 +64,7 @@ struct dm_io_client *dm_io_client_create(unsigned num_pages)
if (!client)
return ERR_PTR(-ENOMEM);
- client->pool = mempool_create_kmalloc_pool(ios, sizeof(struct io));
+ client->pool = mempool_create_slab_pool(ios, _dm_io_cache);
if (!client->pool)
goto bad;
@@ -88,18 +99,29 @@ EXPORT_SYMBOL(dm_io_client_destroy);
/*-----------------------------------------------------------------
* We need to keep track of which region a bio is doing io for.
- * In order to save a memory allocation we store this the last
- * bvec which we know is unused (blech).
- * XXX This is ugly and can OOPS with some configs... find another way.
+ * To avoid a memory allocation to store just 5 or 6 bits, we
+ * ensure the 'struct io' pointer is aligned so enough low bits are
+ * always zero and then combine it with the region number directly in
+ * bi_private.
*---------------------------------------------------------------*/
-static inline void bio_set_region(struct bio *bio, unsigned region)
+static void store_io_and_region_in_bio(struct bio *bio, struct io *io,
+ unsigned region)
{
- bio->bi_io_vec[bio->bi_max_vecs].bv_len = region;
+ if (unlikely(!IS_ALIGNED((unsigned long)io, DM_IO_MAX_REGIONS))) {
+ DMCRIT("Unaligned struct io pointer %p", io);
+ BUG();
+ }
+
+ bio->bi_private = (void *)((unsigned long)io | region);
}
-static inline unsigned bio_get_region(struct bio *bio)
+static void retrieve_io_and_region_from_bio(struct bio *bio, struct io **io,
+ unsigned *region)
{
- return bio->bi_io_vec[bio->bi_max_vecs].bv_len;
+ unsigned long val = (unsigned long)bio->bi_private;
+
+ *io = (void *)(val & -(unsigned long)DM_IO_MAX_REGIONS);
+ *region = val & (DM_IO_MAX_REGIONS - 1);
}
/*-----------------------------------------------------------------
@@ -140,10 +162,8 @@ static void endio(struct bio *bio, int error)
/*
* The bio destructor in bio_put() may use the io object.
*/
- io = bio->bi_private;
- region = bio_get_region(bio);
+ retrieve_io_and_region_from_bio(bio, &io, &region);
- bio->bi_max_vecs++;
bio_put(bio);
dec_count(io, region, error);
@@ -243,7 +263,10 @@ static void vm_dp_init(struct dpages *dp, void *data)
static void dm_bio_destructor(struct bio *bio)
{
- struct io *io = bio->bi_private;
+ unsigned region;
+ struct io *io;
+
+ retrieve_io_and_region_from_bio(bio, &io, &region);
bio_free(bio, io->client->bios);
}
@@ -286,26 +309,23 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
unsigned num_bvecs;
sector_t remaining = where->count;
- while (remaining) {
+ /*
+ * where->count may be zero if rw holds a write barrier and we
+ * need to send a zero-sized barrier.
+ */
+ do {
/*
- * Allocate a suitably sized-bio: we add an extra
- * bvec for bio_get/set_region() and decrement bi_max_vecs
- * to hide it from bio_add_page().
+ * Allocate a suitably sized-bio.
*/
num_bvecs = dm_sector_div_up(remaining,
(PAGE_SIZE >> SECTOR_SHIFT));
- num_bvecs = 1 + min_t(int, bio_get_nr_vecs(where->bdev),
- num_bvecs);
- if (unlikely(num_bvecs > BIO_MAX_PAGES))
- num_bvecs = BIO_MAX_PAGES;
+ num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev), num_bvecs);
bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios);
bio->bi_sector = where->sector + (where->count - remaining);
bio->bi_bdev = where->bdev;
bio->bi_end_io = endio;
- bio->bi_private = io;
bio->bi_destructor = dm_bio_destructor;
- bio->bi_max_vecs--;
- bio_set_region(bio, region);
+ store_io_and_region_in_bio(bio, io, region);
/*
* Try and add as many pages as possible.
@@ -323,7 +343,7 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
atomic_inc(&io->count);
submit_bio(rw, bio);
- }
+ } while (remaining);
}
static void dispatch_io(int rw, unsigned int num_regions,
@@ -333,6 +353,8 @@ static void dispatch_io(int rw, unsigned int num_regions,
int i;
struct dpages old_pages = *dp;
+ BUG_ON(num_regions > DM_IO_MAX_REGIONS);
+
if (sync)
rw |= (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
@@ -342,7 +364,7 @@ static void dispatch_io(int rw, unsigned int num_regions,
*/
for (i = 0; i < num_regions; i++) {
*dp = old_pages;
- if (where[i].count)
+ if (where[i].count || (rw & (1 << BIO_RW_BARRIER)))
do_region(rw, i, where + i, dp, io);
}
@@ -357,7 +379,14 @@ static int sync_io(struct dm_io_client *client, unsigned int num_regions,
struct dm_io_region *where, int rw, struct dpages *dp,
unsigned long *error_bits)
{
- struct io io;
+ /*
+ * gcc <= 4.3 can't do the alignment for stack variables, so we must
+ * align it on our own.
+ * volatile prevents the optimizer from removing or reusing
+ * "io_" field from the stack frame (allowed in ANSI C).
+ */
+ volatile char io_[sizeof(struct io) + __alignof__(struct io) - 1];
+ struct io *io = (struct io *)PTR_ALIGN(&io_, __alignof__(struct io));
if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
WARN_ON(1);
@@ -365,33 +394,33 @@ static int sync_io(struct dm_io_client *client, unsigned int num_regions,
}
retry:
- io.error_bits = 0;
- io.eopnotsupp_bits = 0;
- atomic_set(&io.count, 1); /* see dispatch_io() */
- io.sleeper = current;
- io.client = client;
+ io->error_bits = 0;
+ io->eopnotsupp_bits = 0;
+ atomic_set(&io->count, 1); /* see dispatch_io() */
+ io->sleeper = current;
+ io->client = client;
- dispatch_io(rw, num_regions, where, dp, &io, 1);
+ dispatch_io(rw, num_regions, where, dp, io, 1);
while (1) {
set_current_state(TASK_UNINTERRUPTIBLE);
- if (!atomic_read(&io.count))
+ if (!atomic_read(&io->count))
break;
io_schedule();
}
set_current_state(TASK_RUNNING);
- if (io.eopnotsupp_bits && (rw & (1 << BIO_RW_BARRIER))) {
+ if (io->eopnotsupp_bits && (rw & (1 << BIO_RW_BARRIER))) {
rw &= ~(1 << BIO_RW_BARRIER);
goto retry;
}
if (error_bits)
- *error_bits = io.error_bits;
+ *error_bits = io->error_bits;
- return io.error_bits ? -EIO : 0;
+ return io->error_bits ? -EIO : 0;
}
static int async_io(struct dm_io_client *client, unsigned int num_regions,
@@ -472,3 +501,18 @@ int dm_io(struct dm_io_request *io_req, unsigned num_regions,
&dp, io_req->notify.fn, io_req->notify.context);
}
EXPORT_SYMBOL(dm_io);
+
+int __init dm_io_init(void)
+{
+ _dm_io_cache = KMEM_CACHE(io, 0);
+ if (!_dm_io_cache)
+ return -ENOMEM;
+
+ return 0;
+}
+
+void dm_io_exit(void)
+{
+ kmem_cache_destroy(_dm_io_cache);
+ _dm_io_cache = NULL;
+}
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index a679429..1d66932 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -56,6 +56,11 @@ static void dm_hash_remove_all(int keep_open_devices);
*/
static DECLARE_RWSEM(_hash_lock);
+/*
+ * Protects use of mdptr to obtain hash cell name and uuid from mapped device.
+ */
+static DEFINE_MUTEX(dm_hash_cells_mutex);
+
static void init_buckets(struct list_head *buckets)
{
unsigned int i;
@@ -206,7 +211,9 @@ static int dm_hash_insert(const char *name, const char *uuid, struct mapped_devi
list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
}
dm_get(md);
+ mutex_lock(&dm_hash_cells_mutex);
dm_set_mdptr(md, cell);
+ mutex_unlock(&dm_hash_cells_mutex);
up_write(&_hash_lock);
return 0;
@@ -224,9 +231,11 @@ static void __hash_remove(struct hash_cell *hc)
/* remove from the dev hash */
list_del(&hc->uuid_list);
list_del(&hc->name_list);
+ mutex_lock(&dm_hash_cells_mutex);
dm_set_mdptr(hc->md, NULL);
+ mutex_unlock(&dm_hash_cells_mutex);
- table = dm_get_table(hc->md);
+ table = dm_get_live_table(hc->md);
if (table) {
dm_table_event(table);
dm_table_put(table);
@@ -321,13 +330,15 @@ static int dm_hash_rename(uint32_t cookie, const char *old, const char *new)
*/
list_del(&hc->name_list);
old_name = hc->name;
+ mutex_lock(&dm_hash_cells_mutex);
hc->name = new_name;
+ mutex_unlock(&dm_hash_cells_mutex);
list_add(&hc->name_list, _name_buckets + hash_str(new_name));
/*
* Wake up any dm event waiters.
*/
- table = dm_get_table(hc->md);
+ table = dm_get_live_table(hc->md);
if (table) {
dm_table_event(table);
dm_table_put(table);
@@ -512,8 +523,6 @@ static int list_versions(struct dm_ioctl *param, size_t param_size)
return 0;
}
-
-
static int check_name(const char *name)
{
if (strchr(name, '/')) {
@@ -525,6 +534,40 @@ static int check_name(const char *name)
}
/*
+ * On successful return, the caller must not attempt to acquire
+ * _hash_lock without first calling dm_table_put, because dm_table_destroy
+ * waits for this dm_table_put and could be called under this lock.
+ */
+static struct dm_table *dm_get_inactive_table(struct mapped_device *md)
+{
+ struct hash_cell *hc;
+ struct dm_table *table = NULL;
+
+ down_read(&_hash_lock);
+ hc = dm_get_mdptr(md);
+ if (!hc || hc->md != md) {
+ DMWARN("device has been removed from the dev hash table.");
+ goto out;
+ }
+
+ table = hc->new_map;
+ if (table)
+ dm_table_get(table);
+
+out:
+ up_read(&_hash_lock);
+
+ return table;
+}
+
+static struct dm_table *dm_get_live_or_inactive_table(struct mapped_device *md,
+ struct dm_ioctl *param)
+{
+ return (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) ?
+ dm_get_inactive_table(md) : dm_get_live_table(md);
+}
+
+/*
* Fills in a dm_ioctl structure, ready for sending back to
* userland.
*/
@@ -536,7 +579,7 @@ static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
DM_ACTIVE_PRESENT_FLAG);
- if (dm_suspended(md))
+ if (dm_suspended_md(md))
param->flags |= DM_SUSPEND_FLAG;
param->dev = huge_encode_dev(disk_devt(disk));
@@ -548,18 +591,30 @@ static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
*/
param->open_count = dm_open_count(md);
- if (get_disk_ro(disk))
- param->flags |= DM_READONLY_FLAG;
-
param->event_nr = dm_get_event_nr(md);
+ param->target_count = 0;
- table = dm_get_table(md);
+ table = dm_get_live_table(md);
if (table) {
- param->flags |= DM_ACTIVE_PRESENT_FLAG;
- param->target_count = dm_table_get_num_targets(table);
+ if (!(param->flags & DM_QUERY_INACTIVE_TABLE_FLAG)) {
+ if (get_disk_ro(disk))
+ param->flags |= DM_READONLY_FLAG;
+ param->target_count = dm_table_get_num_targets(table);
+ }
dm_table_put(table);
- } else
- param->target_count = 0;
+
+ param->flags |= DM_ACTIVE_PRESENT_FLAG;
+ }
+
+ if (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) {
+ table = dm_get_inactive_table(md);
+ if (table) {
+ if (!(dm_table_get_mode(table) & FMODE_WRITE))
+ param->flags |= DM_READONLY_FLAG;
+ param->target_count = dm_table_get_num_targets(table);
+ dm_table_put(table);
+ }
+ }
return 0;
}
@@ -634,9 +689,9 @@ static struct mapped_device *find_device(struct dm_ioctl *param)
* Sneakily write in both the name and the uuid
* while we have the cell.
*/
- strncpy(param->name, hc->name, sizeof(param->name));
+ strlcpy(param->name, hc->name, sizeof(param->name));
if (hc->uuid)
- strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
+ strlcpy(param->uuid, hc->uuid, sizeof(param->uuid));
else
param->uuid[0] = '\0';
@@ -784,7 +839,7 @@ static int do_suspend(struct dm_ioctl *param)
if (param->flags & DM_NOFLUSH_FLAG)
suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
- if (!dm_suspended(md))
+ if (!dm_suspended_md(md))
r = dm_suspend(md, suspend_flags);
if (!r)
@@ -800,7 +855,7 @@ static int do_resume(struct dm_ioctl *param)
unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
struct hash_cell *hc;
struct mapped_device *md;
- struct dm_table *new_map;
+ struct dm_table *new_map, *old_map = NULL;
down_write(&_hash_lock);
@@ -826,14 +881,14 @@ static int do_resume(struct dm_ioctl *param)
suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
if (param->flags & DM_NOFLUSH_FLAG)
suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
- if (!dm_suspended(md))
+ if (!dm_suspended_md(md))
dm_suspend(md, suspend_flags);
- r = dm_swap_table(md, new_map);
- if (r) {
+ old_map = dm_swap_table(md, new_map);
+ if (IS_ERR(old_map)) {
dm_table_destroy(new_map);
dm_put(md);
- return r;
+ return PTR_ERR(old_map);
}
if (dm_table_get_mode(new_map) & FMODE_WRITE)
@@ -842,9 +897,11 @@ static int do_resume(struct dm_ioctl *param)
set_disk_ro(dm_disk(md), 1);
}
- if (dm_suspended(md))
+ if (dm_suspended_md(md))
r = dm_resume(md);
+ if (old_map)
+ dm_table_destroy(old_map);
if (!r) {
dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr);
@@ -982,7 +1039,7 @@ static int dev_wait(struct dm_ioctl *param, size_t param_size)
if (r)
goto out;
- table = dm_get_table(md);
+ table = dm_get_live_or_inactive_table(md, param);
if (table) {
retrieve_status(table, param, param_size);
dm_table_put(table);
@@ -1215,7 +1272,7 @@ static int table_deps(struct dm_ioctl *param, size_t param_size)
if (r)
goto out;
- table = dm_get_table(md);
+ table = dm_get_live_or_inactive_table(md, param);
if (table) {
retrieve_deps(table, param, param_size);
dm_table_put(table);
@@ -1244,13 +1301,13 @@ static int table_status(struct dm_ioctl *param, size_t param_size)
if (r)
goto out;
- table = dm_get_table(md);
+ table = dm_get_live_or_inactive_table(md, param);
if (table) {
retrieve_status(table, param, param_size);
dm_table_put(table);
}
- out:
+out:
dm_put(md);
return r;
}
@@ -1288,10 +1345,15 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
goto out;
}
- table = dm_get_table(md);
+ table = dm_get_live_table(md);
if (!table)
goto out_argv;
+ if (dm_deleting_md(md)) {
+ r = -ENXIO;
+ goto out_table;
+ }
+
ti = dm_table_find_target(table, tmsg->sector);
if (!dm_target_is_valid(ti)) {
DMWARN("Target message sector outside device.");
@@ -1303,6 +1365,7 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
r = -EINVAL;
}
+ out_table:
dm_table_put(table);
out_argv:
kfree(argv);
@@ -1582,8 +1645,7 @@ int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
if (!md)
return -ENXIO;
- dm_get(md);
- down_read(&_hash_lock);
+ mutex_lock(&dm_hash_cells_mutex);
hc = dm_get_mdptr(md);
if (!hc || hc->md != md) {
r = -ENXIO;
@@ -1596,8 +1658,7 @@ int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
strcpy(uuid, hc->uuid ? : "");
out:
- up_read(&_hash_lock);
- dm_put(md);
+ mutex_unlock(&dm_hash_cells_mutex);
return r;
}
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index 3e3fc06..addf834 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -450,7 +450,10 @@ static void dispatch_job(struct kcopyd_job *job)
{
struct dm_kcopyd_client *kc = job->kc;
atomic_inc(&kc->nr_jobs);
- push(&kc->pages_jobs, job);
+ if (unlikely(!job->source.count))
+ push(&kc->complete_jobs, job);
+ else
+ push(&kc->pages_jobs, job);
wake(kc);
}
diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index 9443896..7035582 100644
--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -145,8 +145,9 @@ int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type)
EXPORT_SYMBOL(dm_dirty_log_type_unregister);
struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
- struct dm_target *ti,
- unsigned int argc, char **argv)
+ struct dm_target *ti,
+ int (*flush_callback_fn)(struct dm_target *ti),
+ unsigned int argc, char **argv)
{
struct dm_dirty_log_type *type;
struct dm_dirty_log *log;
@@ -161,6 +162,7 @@ struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
return NULL;
}
+ log->flush_callback_fn = flush_callback_fn;
log->type = type;
if (type->ctr(log, ti, argc, argv)) {
kfree(log);
@@ -208,7 +210,9 @@ struct log_header {
struct log_c {
struct dm_target *ti;
- int touched;
+ int touched_dirtied;
+ int touched_cleaned;
+ int flush_failed;
uint32_t region_size;
unsigned int region_count;
region_t sync_count;
@@ -233,6 +237,7 @@ struct log_c {
* Disk log fields
*/
int log_dev_failed;
+ int log_dev_flush_failed;
struct dm_dev *log_dev;
struct log_header header;
@@ -253,14 +258,14 @@ static inline void log_set_bit(struct log_c *l,
uint32_t *bs, unsigned bit)
{
ext2_set_bit(bit, (unsigned long *) bs);
- l->touched = 1;
+ l->touched_cleaned = 1;
}
static inline void log_clear_bit(struct log_c *l,
uint32_t *bs, unsigned bit)
{
ext2_clear_bit(bit, (unsigned long *) bs);
- l->touched = 1;
+ l->touched_dirtied = 1;
}
/*----------------------------------------------------------------
@@ -287,6 +292,19 @@ static int rw_header(struct log_c *lc, int rw)
return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
}
+static int flush_header(struct log_c *lc)
+{
+ struct dm_io_region null_location = {
+ .bdev = lc->header_location.bdev,
+ .sector = 0,
+ .count = 0,
+ };
+
+ lc->io_req.bi_rw = WRITE_BARRIER;
+
+ return dm_io(&lc->io_req, 1, &null_location, NULL);
+}
+
static int read_header(struct log_c *log)
{
int r;
@@ -378,7 +396,9 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
}
lc->ti = ti;
- lc->touched = 0;
+ lc->touched_dirtied = 0;
+ lc->touched_cleaned = 0;
+ lc->flush_failed = 0;
lc->region_size = region_size;
lc->region_count = region_count;
lc->sync = sync;
@@ -406,6 +426,7 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
} else {
lc->log_dev = dev;
lc->log_dev_failed = 0;
+ lc->log_dev_flush_failed = 0;
lc->header_location.bdev = lc->log_dev->bdev;
lc->header_location.sector = 0;
@@ -614,6 +635,11 @@ static int disk_resume(struct dm_dirty_log *log)
/* write the new header */
r = rw_header(lc, WRITE);
+ if (!r) {
+ r = flush_header(lc);
+ if (r)
+ lc->log_dev_flush_failed = 1;
+ }
if (r) {
DMWARN("%s: Failed to write header on dirty region log device",
lc->log_dev->name);
@@ -656,18 +682,40 @@ static int core_flush(struct dm_dirty_log *log)
static int disk_flush(struct dm_dirty_log *log)
{
- int r;
- struct log_c *lc = (struct log_c *) log->context;
+ int r, i;
+ struct log_c *lc = log->context;
/* only write if the log has changed */
- if (!lc->touched)
+ if (!lc->touched_cleaned && !lc->touched_dirtied)
return 0;
+ if (lc->touched_cleaned && log->flush_callback_fn &&
+ log->flush_callback_fn(lc->ti)) {
+ /*
+ * At this point it is impossible to determine which
+ * regions are clean and which are dirty (without
+ * re-reading the log off disk). So mark all of them
+ * dirty.
+ */
+ lc->flush_failed = 1;
+ for (i = 0; i < lc->region_count; i++)
+ log_clear_bit(lc, lc->clean_bits, i);
+ }
+
r = rw_header(lc, WRITE);
if (r)
fail_log_device(lc);
- else
- lc->touched = 0;
+ else {
+ if (lc->touched_dirtied) {
+ r = flush_header(lc);
+ if (r) {
+ lc->log_dev_flush_failed = 1;
+ fail_log_device(lc);
+ } else
+ lc->touched_dirtied = 0;
+ }
+ lc->touched_cleaned = 0;
+ }
return r;
}
@@ -681,7 +729,8 @@ static void core_mark_region(struct dm_dirty_log *log, region_t region)
static void core_clear_region(struct dm_dirty_log *log, region_t region)
{
struct log_c *lc = (struct log_c *) log->context;
- log_set_bit(lc, lc->clean_bits, region);
+ if (likely(!lc->flush_failed))
+ log_set_bit(lc, lc->clean_bits, region);
}
static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
@@ -762,7 +811,9 @@ static int disk_status(struct dm_dirty_log *log, status_type_t status,
switch(status) {
case STATUSTYPE_INFO:
DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
- lc->log_dev_failed ? 'D' : 'A');
+ lc->log_dev_flush_failed ? 'F' :
+ lc->log_dev_failed ? 'D' :
+ 'A');
break;
case STATUSTYPE_TABLE:
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index dce971d..e81345a 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -93,6 +93,10 @@ struct multipath {
* can resubmit bios on error.
*/
mempool_t *mpio_pool;
+
+ struct mutex work_mutex;
+
+ unsigned suspended; /* Don't create new I/O internally when set. */
};
/*
@@ -198,6 +202,7 @@ static struct multipath *alloc_multipath(struct dm_target *ti)
m->queue_io = 1;
INIT_WORK(&m->process_queued_ios, process_queued_ios);
INIT_WORK(&m->trigger_event, trigger_event);
+ mutex_init(&m->work_mutex);
m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
if (!m->mpio_pool) {
kfree(m);
@@ -885,13 +890,18 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
return r;
}
-static void multipath_dtr(struct dm_target *ti)
+static void flush_multipath_work(void)
{
- struct multipath *m = (struct multipath *) ti->private;
-
flush_workqueue(kmpath_handlerd);
flush_workqueue(kmultipathd);
flush_scheduled_work();
+}
+
+static void multipath_dtr(struct dm_target *ti)
+{
+ struct multipath *m = ti->private;
+
+ flush_multipath_work();
free_multipath(m);
}
@@ -1261,6 +1271,16 @@ static void multipath_presuspend(struct dm_target *ti)
queue_if_no_path(m, 0, 1);
}
+static void multipath_postsuspend(struct dm_target *ti)
+{
+ struct multipath *m = ti->private;
+
+ mutex_lock(&m->work_mutex);
+ m->suspended = 1;
+ flush_multipath_work();
+ mutex_unlock(&m->work_mutex);
+}
+
/*
* Restore the queue_if_no_path setting.
*/
@@ -1269,6 +1289,10 @@ static void multipath_resume(struct dm_target *ti)
struct multipath *m = (struct multipath *) ti->private;
unsigned long flags;
+ mutex_lock(&m->work_mutex);
+ m->suspended = 0;
+ mutex_unlock(&m->work_mutex);
+
spin_lock_irqsave(&m->lock, flags);
m->queue_if_no_path = m->saved_queue_if_no_path;
spin_unlock_irqrestore(&m->lock, flags);
@@ -1397,51 +1421,71 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
{
- int r;
+ int r = -EINVAL;
struct dm_dev *dev;
struct multipath *m = (struct multipath *) ti->private;
action_fn action;
+ mutex_lock(&m->work_mutex);
+
+ if (m->suspended) {
+ r = -EBUSY;
+ goto out;
+ }
+
+ if (dm_suspended(ti)) {
+ r = -EBUSY;
+ goto out;
+ }
+
if (argc == 1) {
- if (!strnicmp(argv[0], MESG_STR("queue_if_no_path")))
- return queue_if_no_path(m, 1, 0);
- else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path")))
- return queue_if_no_path(m, 0, 0);
+ if (!strnicmp(argv[0], MESG_STR("queue_if_no_path"))) {
+ r = queue_if_no_path(m, 1, 0);
+ goto out;
+ } else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path"))) {
+ r = queue_if_no_path(m, 0, 0);
+ goto out;
+ }
}
- if (argc != 2)
- goto error;
+ if (argc != 2) {
+ DMWARN("Unrecognised multipath message received.");
+ goto out;
+ }
- if (!strnicmp(argv[0], MESG_STR("disable_group")))
- return bypass_pg_num(m, argv[1], 1);
- else if (!strnicmp(argv[0], MESG_STR("enable_group")))
- return bypass_pg_num(m, argv[1], 0);
- else if (!strnicmp(argv[0], MESG_STR("switch_group")))
- return switch_pg_num(m, argv[1]);
- else if (!strnicmp(argv[0], MESG_STR("reinstate_path")))
+ if (!strnicmp(argv[0], MESG_STR("disable_group"))) {
+ r = bypass_pg_num(m, argv[1], 1);
+ goto out;
+ } else if (!strnicmp(argv[0], MESG_STR("enable_group"))) {
+ r = bypass_pg_num(m, argv[1], 0);
+ goto out;
+ } else if (!strnicmp(argv[0], MESG_STR("switch_group"))) {
+ r = switch_pg_num(m, argv[1]);
+ goto out;
+ } else if (!strnicmp(argv[0], MESG_STR("reinstate_path")))
action = reinstate_path;
else if (!strnicmp(argv[0], MESG_STR("fail_path")))
action = fail_path;
- else
- goto error;
+ else {
+ DMWARN("Unrecognised multipath message received.");
+ goto out;
+ }
r = dm_get_device(ti, argv[1], ti->begin, ti->len,
dm_table_get_mode(ti->table), &dev);
if (r) {
DMWARN("message: error getting device %s",
argv[1]);
- return -EINVAL;
+ goto out;
}
r = action_dev(m, dev, action);
dm_put_device(ti, dev);
+out:
+ mutex_unlock(&m->work_mutex);
return r;
-
-error:
- DMWARN("Unrecognised multipath message received.");
- return -EINVAL;
}
static int multipath_ioctl(struct dm_target *ti, unsigned int cmd,
@@ -1567,13 +1611,14 @@ out:
*---------------------------------------------------------------*/
static struct target_type multipath_target = {
.name = "multipath",
- .version = {1, 1, 0},
+ .version = {1, 1, 1},
.module = THIS_MODULE,
.ctr = multipath_ctr,
.dtr = multipath_dtr,
.map_rq = multipath_map,
.rq_end_io = multipath_end_io,
.presuspend = multipath_presuspend,
+ .postsuspend = multipath_postsuspend,
.resume = multipath_resume,
.status = multipath_status,
.message = multipath_message,
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index cc9dc79..ad779bd 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -35,6 +35,7 @@ static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
*---------------------------------------------------------------*/
enum dm_raid1_error {
DM_RAID1_WRITE_ERROR,
+ DM_RAID1_FLUSH_ERROR,
DM_RAID1_SYNC_ERROR,
DM_RAID1_READ_ERROR
};
@@ -57,6 +58,7 @@ struct mirror_set {
struct bio_list reads;
struct bio_list writes;
struct bio_list failures;
+ struct bio_list holds; /* bios are waiting until suspend */
struct dm_region_hash *rh;
struct dm_kcopyd_client *kcopyd_client;
@@ -67,6 +69,7 @@ struct mirror_set {
region_t nr_regions;
int in_sync;
int log_failure;
+ int leg_failure;
atomic_t suspend;
atomic_t default_mirror; /* Default mirror */
@@ -179,6 +182,17 @@ static void set_default_mirror(struct mirror *m)
atomic_set(&ms->default_mirror, m - m0);
}
+static struct mirror *get_valid_mirror(struct mirror_set *ms)
+{
+ struct mirror *m;
+
+ for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++)
+ if (!atomic_read(&m->error_count))
+ return m;
+
+ return NULL;
+}
+
/* fail_mirror
* @m: mirror device to fail
* @error_type: one of the enum's, DM_RAID1_*_ERROR
@@ -198,6 +212,8 @@ static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
struct mirror_set *ms = m->ms;
struct mirror *new;
+ ms->leg_failure = 1;
+
/*
* error_count is used for nothing more than a
* simple way to tell if a device has encountered
@@ -224,19 +240,50 @@ static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
goto out;
}
- for (new = ms->mirror; new < ms->mirror + ms->nr_mirrors; new++)
- if (!atomic_read(&new->error_count)) {
- set_default_mirror(new);
- break;
- }
-
- if (unlikely(new == ms->mirror + ms->nr_mirrors))
+ new = get_valid_mirror(ms);
+ if (new)
+ set_default_mirror(new);
+ else
DMWARN("All sides of mirror have failed.");
out:
schedule_work(&ms->trigger_event);
}
+static int mirror_flush(struct dm_target *ti)
+{
+ struct mirror_set *ms = ti->private;
+ unsigned long error_bits;
+
+ unsigned int i;
+ struct dm_io_region io[ms->nr_mirrors];
+ struct mirror *m;
+ struct dm_io_request io_req = {
+ .bi_rw = WRITE_BARRIER,
+ .mem.type = DM_IO_KMEM,
+ .mem.ptr.bvec = NULL,
+ .client = ms->io_client,
+ };
+
+ for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) {
+ io[i].bdev = m->dev->bdev;
+ io[i].sector = 0;
+ io[i].count = 0;
+ }
+
+ error_bits = -1;
+ dm_io(&io_req, ms->nr_mirrors, io, &error_bits);
+ if (unlikely(error_bits != 0)) {
+ for (i = 0; i < ms->nr_mirrors; i++)
+ if (test_bit(i, &error_bits))
+ fail_mirror(ms->mirror + i,
+ DM_RAID1_FLUSH_ERROR);
+ return -EIO;
+ }
+
+ return 0;
+}
+
/*-----------------------------------------------------------------
* Recovery.
*
@@ -396,6 +443,8 @@ static int mirror_available(struct mirror_set *ms, struct bio *bio)
*/
static sector_t map_sector(struct mirror *m, struct bio *bio)
{
+ if (unlikely(!bio->bi_size))
+ return 0;
return m->offset + (bio->bi_sector - m->ms->ti->begin);
}
@@ -413,6 +462,27 @@ static void map_region(struct dm_io_region *io, struct mirror *m,
io->count = bio->bi_size >> 9;
}
+static void hold_bio(struct mirror_set *ms, struct bio *bio)
+{
+ /*
+ * If device is suspended, complete the bio.
+ */
+ if (atomic_read(&ms->suspend)) {
+ if (dm_noflush_suspending(ms->ti))
+ bio_endio(bio, DM_ENDIO_REQUEUE);
+ else
+ bio_endio(bio, -EIO);
+ return;
+ }
+
+ /*
+ * Hold bio until the suspend is complete.
+ */
+ spin_lock_irq(&ms->lock);
+ bio_list_add(&ms->holds, bio);
+ spin_unlock_irq(&ms->lock);
+}
+
/*-----------------------------------------------------------------
* Reads
*---------------------------------------------------------------*/
@@ -511,7 +581,6 @@ static void write_callback(unsigned long error, void *context)
unsigned i, ret = 0;
struct bio *bio = (struct bio *) context;
struct mirror_set *ms;
- int uptodate = 0;
int should_wake = 0;
unsigned long flags;
@@ -524,36 +593,27 @@ static void write_callback(unsigned long error, void *context)
* This way we handle both writes to SYNC and NOSYNC
* regions with the same code.
*/
- if (likely(!error))
- goto out;
+ if (likely(!error)) {
+ bio_endio(bio, ret);
+ return;
+ }
for (i = 0; i < ms->nr_mirrors; i++)
if (test_bit(i, &error))
fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR);
- else
- uptodate = 1;
- if (unlikely(!uptodate)) {
- DMERR("All replicated volumes dead, failing I/O");
- /* None of the writes succeeded, fail the I/O. */
- ret = -EIO;
- } else if (errors_handled(ms)) {
- /*
- * Need to raise event. Since raising
- * events can block, we need to do it in
- * the main thread.
- */
- spin_lock_irqsave(&ms->lock, flags);
- if (!ms->failures.head)
- should_wake = 1;
- bio_list_add(&ms->failures, bio);
- spin_unlock_irqrestore(&ms->lock, flags);
- if (should_wake)
- wakeup_mirrord(ms);
- return;
- }
-out:
- bio_endio(bio, ret);
+ /*
+ * Need to raise event. Since raising
+ * events can block, we need to do it in
+ * the main thread.
+ */
+ spin_lock_irqsave(&ms->lock, flags);
+ if (!ms->failures.head)
+ should_wake = 1;
+ bio_list_add(&ms->failures, bio);
+ spin_unlock_irqrestore(&ms->lock, flags);
+ if (should_wake)
+ wakeup_mirrord(ms);
}
static void do_write(struct mirror_set *ms, struct bio *bio)
@@ -562,7 +622,7 @@ static void do_write(struct mirror_set *ms, struct bio *bio)
struct dm_io_region io[ms->nr_mirrors], *dest = io;
struct mirror *m;
struct dm_io_request io_req = {
- .bi_rw = WRITE,
+ .bi_rw = WRITE | (bio->bi_rw & WRITE_BARRIER),
.mem.type = DM_IO_BVEC,
.mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx,
.notify.fn = write_callback,
@@ -603,6 +663,11 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes)
bio_list_init(&requeue);
while ((bio = bio_list_pop(writes))) {
+ if (unlikely(bio_empty_barrier(bio))) {
+ bio_list_add(&sync, bio);
+ continue;
+ }
+
region = dm_rh_bio_to_region(ms->rh, bio);
if (log->type->is_remote_recovering &&
@@ -672,8 +737,12 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes)
dm_rh_delay(ms->rh, bio);
while ((bio = bio_list_pop(&nosync))) {
- map_bio(get_default_mirror(ms), bio);
- generic_make_request(bio);
+ if (unlikely(ms->leg_failure) && errors_handled(ms))
+ hold_bio(ms, bio);
+ else {
+ map_bio(get_default_mirror(ms), bio);
+ generic_make_request(bio);
+ }
}
}
@@ -681,20 +750,12 @@ static void do_failures(struct mirror_set *ms, struct bio_list *failures)
{
struct bio *bio;
- if (!failures->head)
- return;
-
- if (!ms->log_failure) {
- while ((bio = bio_list_pop(failures))) {
- ms->in_sync = 0;
- dm_rh_mark_nosync(ms->rh, bio, bio->bi_size, 0);
- }
+ if (likely(!failures->head))
return;
- }
/*
* If the log has failed, unattempted writes are being
- * put on the failures list. We can't issue those writes
+ * put on the holds list. We can't issue those writes
* until a log has been marked, so we must store them.
*
* If a 'noflush' suspend is in progress, we can requeue
@@ -709,23 +770,27 @@ static void do_failures(struct mirror_set *ms, struct bio_list *failures)
* for us to treat them the same and requeue them
* as well.
*/
- if (dm_noflush_suspending(ms->ti)) {
- while ((bio = bio_list_pop(failures)))
- bio_endio(bio, DM_ENDIO_REQUEUE);
- return;
- }
+ while ((bio = bio_list_pop(failures))) {
+ if (!ms->log_failure) {
+ ms->in_sync = 0;
+ dm_rh_mark_nosync(ms->rh, bio);
+ }
- if (atomic_read(&ms->suspend)) {
- while ((bio = bio_list_pop(failures)))
+ /*
+ * If all the legs are dead, fail the I/O.
+ * If we have been told to handle errors, hold the bio
+ * and wait for userspace to deal with the problem.
+ * Otherwise pretend that the I/O succeeded. (This would
+ * be wrong if the failed leg returned after reboot and
+ * got replicated back to the good legs.)
+ */
+ if (!get_valid_mirror(ms))
bio_endio(bio, -EIO);
- return;
+ else if (errors_handled(ms))
+ hold_bio(ms, bio);
+ else
+ bio_endio(bio, 0);
}
-
- spin_lock_irq(&ms->lock);
- bio_list_merge(&ms->failures, failures);
- spin_unlock_irq(&ms->lock);
-
- delayed_wake(ms);
}
static void trigger_event(struct work_struct *work)
@@ -784,12 +849,17 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors,
}
spin_lock_init(&ms->lock);
+ bio_list_init(&ms->reads);
+ bio_list_init(&ms->writes);
+ bio_list_init(&ms->failures);
+ bio_list_init(&ms->holds);
ms->ti = ti;
ms->nr_mirrors = nr_mirrors;
ms->nr_regions = dm_sector_div_up(ti->len, region_size);
ms->in_sync = 0;
ms->log_failure = 0;
+ ms->leg_failure = 0;
atomic_set(&ms->suspend, 0);
atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
@@ -889,7 +959,8 @@ static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
return NULL;
}
- dl = dm_dirty_log_create(argv[0], ti, param_count, argv + 2);
+ dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count,
+ argv + 2);
if (!dl) {
ti->error = "Error creating mirror dirty log";
return NULL;
@@ -995,6 +1066,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
ti->private = ms;
ti->split_io = dm_rh_get_region_size(ms->rh);
+ ti->num_flush_requests = 1;
ms->kmirrord_wq = create_singlethread_workqueue("kmirrord");
if (!ms->kmirrord_wq) {
@@ -1122,7 +1194,8 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio,
* We need to dec pending if this was a write.
*/
if (rw == WRITE) {
- dm_rh_dec(ms->rh, map_context->ll);
+ if (likely(!bio_empty_barrier(bio)))
+ dm_rh_dec(ms->rh, map_context->ll);
return error;
}
@@ -1180,6 +1253,9 @@ static void mirror_presuspend(struct dm_target *ti)
struct mirror_set *ms = (struct mirror_set *) ti->private;
struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
+ struct bio_list holds;
+ struct bio *bio;
+
atomic_set(&ms->suspend, 1);
/*
@@ -1202,6 +1278,22 @@ static void mirror_presuspend(struct dm_target *ti)
* we know that all of our I/O has been pushed.
*/
flush_workqueue(ms->kmirrord_wq);
+
+ /*
+ * Now set ms->suspend is set and the workqueue flushed, no more
+ * entries can be added to ms->hold list, so process it.
+ *
+ * Bios can still arrive concurrently with or after this
+ * presuspend function, but they cannot join the hold list
+ * because ms->suspend is set.
+ */
+ spin_lock_irq(&ms->lock);
+ holds = ms->holds;
+ bio_list_init(&ms->holds);
+ spin_unlock_irq(&ms->lock);
+
+ while ((bio = bio_list_pop(&holds)))
+ hold_bio(ms, bio);
}
static void mirror_postsuspend(struct dm_target *ti)
@@ -1244,7 +1336,8 @@ static char device_status_char(struct mirror *m)
if (!atomic_read(&(m->error_count)))
return 'A';
- return (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
+ return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' :
+ (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
(test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' :
(test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U';
}
diff --git a/drivers/md/dm-region-hash.c b/drivers/md/dm-region-hash.c
index 36dbe29..5f19ceb 100644
--- a/drivers/md/dm-region-hash.c
+++ b/drivers/md/dm-region-hash.c
@@ -79,6 +79,11 @@ struct dm_region_hash {
struct list_head recovered_regions;
struct list_head failed_recovered_regions;
+ /*
+ * If there was a barrier failure no regions can be marked clean.
+ */
+ int barrier_failure;
+
void *context;
sector_t target_begin;
@@ -211,6 +216,7 @@ struct dm_region_hash *dm_region_hash_create(
INIT_LIST_HEAD(&rh->quiesced_regions);
INIT_LIST_HEAD(&rh->recovered_regions);
INIT_LIST_HEAD(&rh->failed_recovered_regions);
+ rh->barrier_failure = 0;
rh->region_pool = mempool_create_kmalloc_pool(MIN_REGIONS,
sizeof(struct dm_region));
@@ -377,8 +383,6 @@ static void complete_resync_work(struct dm_region *reg, int success)
/* dm_rh_mark_nosync
* @ms
* @bio
- * @done
- * @error
*
* The bio was written on some mirror(s) but failed on other mirror(s).
* We can successfully endio the bio but should avoid the region being
@@ -386,8 +390,7 @@ static void complete_resync_work(struct dm_region *reg, int success)
*
* This function is _not_ safe in interrupt context!
*/
-void dm_rh_mark_nosync(struct dm_region_hash *rh,
- struct bio *bio, unsigned done, int error)
+void dm_rh_mark_nosync(struct dm_region_hash *rh, struct bio *bio)
{
unsigned long flags;
struct dm_dirty_log *log = rh->log;
@@ -395,6 +398,11 @@ void dm_rh_mark_nosync(struct dm_region_hash *rh,
region_t region = dm_rh_bio_to_region(rh, bio);
int recovering = 0;
+ if (bio_empty_barrier(bio)) {
+ rh->barrier_failure = 1;
+ return;
+ }
+
/* We must inform the log that the sync count has changed. */
log->type->set_region_sync(log, region, 0);
@@ -419,7 +427,6 @@ void dm_rh_mark_nosync(struct dm_region_hash *rh,
BUG_ON(!list_empty(&reg->list));
spin_unlock_irqrestore(&rh->region_lock, flags);
- bio_endio(bio, error);
if (recovering)
complete_resync_work(reg, 0);
}
@@ -515,8 +522,11 @@ void dm_rh_inc_pending(struct dm_region_hash *rh, struct bio_list *bios)
{
struct bio *bio;
- for (bio = bios->head; bio; bio = bio->bi_next)
+ for (bio = bios->head; bio; bio = bio->bi_next) {
+ if (bio_empty_barrier(bio))
+ continue;
rh_inc(rh, dm_rh_bio_to_region(rh, bio));
+ }
}
EXPORT_SYMBOL_GPL(dm_rh_inc_pending);
@@ -544,7 +554,14 @@ void dm_rh_dec(struct dm_region_hash *rh, region_t region)
*/
/* do nothing for DM_RH_NOSYNC */
- if (reg->state == DM_RH_RECOVERING) {
+ if (unlikely(rh->barrier_failure)) {
+ /*
+ * If a write barrier failed some time ago, we
+ * don't know whether or not this write made it
+ * to the disk, so we must resync the device.
+ */
+ reg->state = DM_RH_NOSYNC;
+ } else if (reg->state == DM_RH_RECOVERING) {
list_add_tail(&reg->list, &rh->quiesced_regions);
} else if (reg->state == DM_RH_DIRTY) {
reg->state = DM_RH_CLEAN;
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index 0c74642..7d08879 100644
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -55,6 +55,8 @@
*/
#define SNAPSHOT_DISK_VERSION 1
+#define NUM_SNAPSHOT_HDR_CHUNKS 1
+
struct disk_header {
uint32_t magic;
@@ -120,7 +122,22 @@ struct pstore {
/*
* The next free chunk for an exception.
+ *
+ * When creating exceptions, all the chunks here and above are
+ * free. It holds the next chunk to be allocated. On rare
+ * occasions (e.g. after a system crash) holes can be left in
+ * the exception store because chunks can be committed out of
+ * order.
+ *
+ * When merging exceptions, it does not necessarily mean all the
+ * chunks here and above are free. It holds the value it would
+ * have held if all chunks had been committed in order of
+ * allocation. Consequently the value may occasionally be
+ * slightly too low, but since it's only used for 'status' and
+ * it can never reach its minimum value too early this doesn't
+ * matter.
*/
+
chunk_t next_free;
/*
@@ -214,7 +231,7 @@ static int chunk_io(struct pstore *ps, void *area, chunk_t chunk, int rw,
int metadata)
{
struct dm_io_region where = {
- .bdev = ps->store->cow->bdev,
+ .bdev = dm_snap_cow(ps->store->snap)->bdev,
.sector = ps->store->chunk_size * chunk,
.count = ps->store->chunk_size,
};
@@ -294,7 +311,8 @@ static int read_header(struct pstore *ps, int *new_snapshot)
*/
if (!ps->store->chunk_size) {
ps->store->chunk_size = max(DM_CHUNK_SIZE_DEFAULT_SECTORS,
- bdev_logical_block_size(ps->store->cow->bdev) >> 9);
+ bdev_logical_block_size(dm_snap_cow(ps->store->snap)->
+ bdev) >> 9);
ps->store->chunk_mask = ps->store->chunk_size - 1;
ps->store->chunk_shift = ffs(ps->store->chunk_size) - 1;
chunk_size_supplied = 0;
@@ -408,6 +426,15 @@ static void write_exception(struct pstore *ps,
e->new_chunk = cpu_to_le64(de->new_chunk);
}
+static void clear_exception(struct pstore *ps, uint32_t index)
+{
+ struct disk_exception *e = get_exception(ps, index);
+
+ /* clear it */
+ e->old_chunk = 0;
+ e->new_chunk = 0;
+}
+
/*
* Registers the exceptions that are present in the current area.
* 'full' is filled in to indicate if the area has been
@@ -489,11 +516,23 @@ static struct pstore *get_info(struct dm_exception_store *store)
return (struct pstore *) store->context;
}
-static void persistent_fraction_full(struct dm_exception_store *store,
- sector_t *numerator, sector_t *denominator)
+static void persistent_usage(struct dm_exception_store *store,
+ sector_t *total_sectors,
+ sector_t *sectors_allocated,
+ sector_t *metadata_sectors)
{
- *numerator = get_info(store)->next_free * store->chunk_size;
- *denominator = get_dev_size(store->cow->bdev);
+ struct pstore *ps = get_info(store);
+
+ *sectors_allocated = ps->next_free * store->chunk_size;
+ *total_sectors = get_dev_size(dm_snap_cow(store->snap)->bdev);
+
+ /*
+ * First chunk is the fixed header.
+ * Then there are (ps->current_area + 1) metadata chunks, each one
+ * separated from the next by ps->exceptions_per_area data chunks.
+ */
+ *metadata_sectors = (ps->current_area + 1 + NUM_SNAPSHOT_HDR_CHUNKS) *
+ store->chunk_size;
}
static void persistent_dtr(struct dm_exception_store *store)
@@ -552,44 +591,40 @@ static int persistent_read_metadata(struct dm_exception_store *store,
ps->current_area = 0;
zero_memory_area(ps);
r = zero_disk_area(ps, 0);
- if (r) {
+ if (r)
DMWARN("zero_disk_area(0) failed");
- return r;
- }
- } else {
- /*
- * Sanity checks.
- */
- if (ps->version != SNAPSHOT_DISK_VERSION) {
- DMWARN("unable to handle snapshot disk version %d",
- ps->version);
- return -EINVAL;
- }
+ return r;
+ }
+ /*
+ * Sanity checks.
+ */
+ if (ps->version != SNAPSHOT_DISK_VERSION) {
+ DMWARN("unable to handle snapshot disk version %d",
+ ps->version);
+ return -EINVAL;
+ }
- /*
- * Metadata are valid, but snapshot is invalidated
- */
- if (!ps->valid)
- return 1;
+ /*
+ * Metadata are valid, but snapshot is invalidated
+ */
+ if (!ps->valid)
+ return 1;
- /*
- * Read the metadata.
- */
- r = read_exceptions(ps, callback, callback_context);
- if (r)
- return r;
- }
+ /*
+ * Read the metadata.
+ */
+ r = read_exceptions(ps, callback, callback_context);
- return 0;
+ return r;
}
static int persistent_prepare_exception(struct dm_exception_store *store,
- struct dm_snap_exception *e)
+ struct dm_exception *e)
{
struct pstore *ps = get_info(store);
uint32_t stride;
chunk_t next_free;
- sector_t size = get_dev_size(store->cow->bdev);
+ sector_t size = get_dev_size(dm_snap_cow(store->snap)->bdev);
/* Is there enough room ? */
if (size < ((ps->next_free + 1) * store->chunk_size))
@@ -611,7 +646,7 @@ static int persistent_prepare_exception(struct dm_exception_store *store,
}
static void persistent_commit_exception(struct dm_exception_store *store,
- struct dm_snap_exception *e,
+ struct dm_exception *e,
void (*callback) (void *, int success),
void *callback_context)
{
@@ -672,6 +707,85 @@ static void persistent_commit_exception(struct dm_exception_store *store,
ps->callback_count = 0;
}
+static int persistent_prepare_merge(struct dm_exception_store *store,
+ chunk_t *last_old_chunk,
+ chunk_t *last_new_chunk)
+{
+ struct pstore *ps = get_info(store);
+ struct disk_exception de;
+ int nr_consecutive;
+ int r;
+
+ /*
+ * When current area is empty, move back to preceding area.
+ */
+ if (!ps->current_committed) {
+ /*
+ * Have we finished?
+ */
+ if (!ps->current_area)
+ return 0;
+
+ ps->current_area--;
+ r = area_io(ps, READ);
+ if (r < 0)
+ return r;
+ ps->current_committed = ps->exceptions_per_area;
+ }
+
+ read_exception(ps, ps->current_committed - 1, &de);
+ *last_old_chunk = de.old_chunk;
+ *last_new_chunk = de.new_chunk;
+
+ /*
+ * Find number of consecutive chunks within the current area,
+ * working backwards.
+ */
+ for (nr_consecutive = 1; nr_consecutive < ps->current_committed;
+ nr_consecutive++) {
+ read_exception(ps, ps->current_committed - 1 - nr_consecutive,
+ &de);
+ if (de.old_chunk != *last_old_chunk - nr_consecutive ||
+ de.new_chunk != *last_new_chunk - nr_consecutive)
+ break;
+ }
+
+ return nr_consecutive;
+}
+
+static int persistent_commit_merge(struct dm_exception_store *store,
+ int nr_merged)
+{
+ int r, i;
+ struct pstore *ps = get_info(store);
+
+ BUG_ON(nr_merged > ps->current_committed);
+
+ for (i = 0; i < nr_merged; i++)
+ clear_exception(ps, ps->current_committed - 1 - i);
+
+ r = area_io(ps, WRITE);
+ if (r < 0)
+ return r;
+
+ ps->current_committed -= nr_merged;
+
+ /*
+ * At this stage, only persistent_usage() uses ps->next_free, so
+ * we make no attempt to keep ps->next_free strictly accurate
+ * as exceptions may have been committed out-of-order originally.
+ * Once a snapshot has become merging, we set it to the value it
+ * would have held had all the exceptions been committed in order.
+ *
+ * ps->current_area does not get reduced by prepare_merge() until
+ * after commit_merge() has removed the nr_merged previous exceptions.
+ */
+ ps->next_free = (area_location(ps, ps->current_area) - 1) +
+ (ps->current_committed + 1) + NUM_SNAPSHOT_HDR_CHUNKS;
+
+ return 0;
+}
+
static void persistent_drop_snapshot(struct dm_exception_store *store)
{
struct pstore *ps = get_info(store);
@@ -697,7 +811,7 @@ static int persistent_ctr(struct dm_exception_store *store,
ps->area = NULL;
ps->zero_area = NULL;
ps->header_area = NULL;
- ps->next_free = 2; /* skipping the header and first area */
+ ps->next_free = NUM_SNAPSHOT_HDR_CHUNKS + 1; /* header and 1st area */
ps->current_committed = 0;
ps->callback_count = 0;
@@ -726,8 +840,7 @@ static unsigned persistent_status(struct dm_exception_store *store,
case STATUSTYPE_INFO:
break;
case STATUSTYPE_TABLE:
- DMEMIT(" %s P %llu", store->cow->name,
- (unsigned long long)store->chunk_size);
+ DMEMIT(" P %llu", (unsigned long long)store->chunk_size);
}
return sz;
@@ -741,8 +854,10 @@ static struct dm_exception_store_type _persistent_type = {
.read_metadata = persistent_read_metadata,
.prepare_exception = persistent_prepare_exception,
.commit_exception = persistent_commit_exception,
+ .prepare_merge = persistent_prepare_merge,
+ .commit_merge = persistent_commit_merge,
.drop_snapshot = persistent_drop_snapshot,
- .fraction_full = persistent_fraction_full,
+ .usage = persistent_usage,
.status = persistent_status,
};
@@ -754,8 +869,10 @@ static struct dm_exception_store_type _persistent_compat_type = {
.read_metadata = persistent_read_metadata,
.prepare_exception = persistent_prepare_exception,
.commit_exception = persistent_commit_exception,
+ .prepare_merge = persistent_prepare_merge,
+ .commit_merge = persistent_commit_merge,
.drop_snapshot = persistent_drop_snapshot,
- .fraction_full = persistent_fraction_full,
+ .usage = persistent_usage,
.status = persistent_status,
};
diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c
index cde5aa5..a0898a6 100644
--- a/drivers/md/dm-snap-transient.c
+++ b/drivers/md/dm-snap-transient.c
@@ -36,10 +36,10 @@ static int transient_read_metadata(struct dm_exception_store *store,
}
static int transient_prepare_exception(struct dm_exception_store *store,
- struct dm_snap_exception *e)
+ struct dm_exception *e)
{
struct transient_c *tc = store->context;
- sector_t size = get_dev_size(store->cow->bdev);
+ sector_t size = get_dev_size(dm_snap_cow(store->snap)->bdev);
if (size < (tc->next_free + store->chunk_size))
return -1;
@@ -51,7 +51,7 @@ static int transient_prepare_exception(struct dm_exception_store *store,
}
static void transient_commit_exception(struct dm_exception_store *store,
- struct dm_snap_exception *e,
+ struct dm_exception *e,
void (*callback) (void *, int success),
void *callback_context)
{
@@ -59,11 +59,14 @@ static void transient_commit_exception(struct dm_exception_store *store,
callback(callback_context, 1);
}
-static void transient_fraction_full(struct dm_exception_store *store,
- sector_t *numerator, sector_t *denominator)
+static void transient_usage(struct dm_exception_store *store,
+ sector_t *total_sectors,
+ sector_t *sectors_allocated,
+ sector_t *metadata_sectors)
{
- *numerator = ((struct transient_c *) store->context)->next_free;
- *denominator = get_dev_size(store->cow->bdev);
+ *sectors_allocated = ((struct transient_c *) store->context)->next_free;
+ *total_sectors = get_dev_size(dm_snap_cow(store->snap)->bdev);
+ *metadata_sectors = 0;
}
static int transient_ctr(struct dm_exception_store *store,
@@ -91,8 +94,7 @@ static unsigned transient_status(struct dm_exception_store *store,
case STATUSTYPE_INFO:
break;
case STATUSTYPE_TABLE:
- DMEMIT(" %s N %llu", store->cow->name,
- (unsigned long long)store->chunk_size);
+ DMEMIT(" N %llu", (unsigned long long)store->chunk_size);
}
return sz;
@@ -106,7 +108,7 @@ static struct dm_exception_store_type _transient_type = {
.read_metadata = transient_read_metadata,
.prepare_exception = transient_prepare_exception,
.commit_exception = transient_commit_exception,
- .fraction_full = transient_fraction_full,
+ .usage = transient_usage,
.status = transient_status,
};
@@ -118,7 +120,7 @@ static struct dm_exception_store_type _transient_compat_type = {
.read_metadata = transient_read_metadata,
.prepare_exception = transient_prepare_exception,
.commit_exception = transient_commit_exception,
- .fraction_full = transient_fraction_full,
+ .usage = transient_usage,
.status = transient_status,
};
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 3a3ba46..ee8eb28 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -25,6 +25,11 @@
#define DM_MSG_PREFIX "snapshots"
+static const char dm_snapshot_merge_target_name[] = "snapshot-merge";
+
+#define dm_target_is_snapshot_merge(ti) \
+ ((ti)->type->name == dm_snapshot_merge_target_name)
+
/*
* The percentage increment we will wake up users at
*/
@@ -49,7 +54,7 @@
#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \
(DM_TRACKED_CHUNK_HASH_SIZE - 1))
-struct exception_table {
+struct dm_exception_table {
uint32_t hash_mask;
unsigned hash_shift;
struct list_head *table;
@@ -59,22 +64,31 @@ struct dm_snapshot {
struct rw_semaphore lock;
struct dm_dev *origin;
+ struct dm_dev *cow;
+
+ struct dm_target *ti;
/* List of snapshots per Origin */
struct list_head list;
- /* You can't use a snapshot if this is 0 (e.g. if full) */
+ /*
+ * You can't use a snapshot if this is 0 (e.g. if full).
+ * A snapshot-merge target never clears this.
+ */
int valid;
/* Origin writes don't trigger exceptions until this is set */
int active;
+ /* Whether or not owning mapped_device is suspended */
+ int suspended;
+
mempool_t *pending_pool;
atomic_t pending_exceptions_count;
- struct exception_table pending;
- struct exception_table complete;
+ struct dm_exception_table pending;
+ struct dm_exception_table complete;
/*
* pe_lock protects all pending_exception operations and access
@@ -95,8 +109,51 @@ struct dm_snapshot {
mempool_t *tracked_chunk_pool;
spinlock_t tracked_chunk_lock;
struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE];
+
+ /*
+ * The merge operation failed if this flag is set.
+ * Failure modes are handled as follows:
+ * - I/O error reading the header
+ * => don't load the target; abort.
+ * - Header does not have "valid" flag set
+ * => use the origin; forget about the snapshot.
+ * - I/O error when reading exceptions
+ * => don't load the target; abort.
+ * (We can't use the intermediate origin state.)
+ * - I/O error while merging
+ * => stop merging; set merge_failed; process I/O normally.
+ */
+ int merge_failed;
+
+ /* Wait for events based on state_bits */
+ unsigned long state_bits;
+
+ /* Range of chunks currently being merged. */
+ chunk_t first_merging_chunk;
+ int num_merging_chunks;
+
+ /*
+ * Incoming bios that overlap with chunks being merged must wait
+ * for them to be committed.
+ */
+ struct bio_list bios_queued_during_merge;
};
+/*
+ * state_bits:
+ * RUNNING_MERGE - Merge operation is in progress.
+ * SHUTDOWN_MERGE - Set to signal that merge needs to be stopped;
+ * cleared afterwards.
+ */
+#define RUNNING_MERGE 0
+#define SHUTDOWN_MERGE 1
+
+struct dm_dev *dm_snap_cow(struct dm_snapshot *s)
+{
+ return s->cow;
+}
+EXPORT_SYMBOL(dm_snap_cow);
+
static struct workqueue_struct *ksnapd;
static void flush_queued_bios(struct work_struct *work);
@@ -116,7 +173,7 @@ static int bdev_equal(struct block_device *lhs, struct block_device *rhs)
}
struct dm_snap_pending_exception {
- struct dm_snap_exception e;
+ struct dm_exception e;
/*
* Origin buffers waiting for this to complete are held
@@ -125,28 +182,6 @@ struct dm_snap_pending_exception {
struct bio_list origin_bios;
struct bio_list snapshot_bios;
- /*
- * Short-term queue of pending exceptions prior to submission.
- */
- struct list_head list;
-
- /*
- * The primary pending_exception is the one that holds
- * the ref_count and the list of origin_bios for a
- * group of pending_exceptions. It is always last to get freed.
- * These fields get set up when writing to the origin.
- */
- struct dm_snap_pending_exception *primary_pe;
-
- /*
- * Number of pending_exceptions processing this chunk.
- * When this drops to zero we must complete the origin bios.
- * If incrementing or decrementing this, hold pe->snap->lock for
- * the sibling concerned and not pe->primary_pe->snap->lock unless
- * they are the same.
- */
- atomic_t ref_count;
-
/* Pointer back to snapshot context */
struct dm_snapshot *snap;
@@ -222,6 +257,16 @@ static int __chunk_is_tracked(struct dm_snapshot *s, chunk_t chunk)
}
/*
+ * This conflicting I/O is extremely improbable in the caller,
+ * so msleep(1) is sufficient and there is no need for a wait queue.
+ */
+static void __check_for_conflicting_io(struct dm_snapshot *s, chunk_t chunk)
+{
+ while (__chunk_is_tracked(s, chunk))
+ msleep(1);
+}
+
+/*
* One of these per registered origin, held in the snapshot_origins hash
*/
struct origin {
@@ -243,6 +288,10 @@ struct origin {
static struct list_head *_origins;
static struct rw_semaphore _origins_lock;
+static DECLARE_WAIT_QUEUE_HEAD(_pending_exceptions_done);
+static DEFINE_SPINLOCK(_pending_exceptions_done_spinlock);
+static uint64_t _pending_exceptions_done_count;
+
static int init_origin_hash(void)
{
int i;
@@ -291,22 +340,144 @@ static void __insert_origin(struct origin *o)
}
/*
+ * _origins_lock must be held when calling this function.
+ * Returns number of snapshots registered using the supplied cow device, plus:
+ * snap_src - a snapshot suitable for use as a source of exception handover
+ * snap_dest - a snapshot capable of receiving exception handover.
+ * snap_merge - an existing snapshot-merge target linked to the same origin.
+ * There can be at most one snapshot-merge target. The parameter is optional.
+ *
+ * Possible return values and states of snap_src and snap_dest.
+ * 0: NULL, NULL - first new snapshot
+ * 1: snap_src, NULL - normal snapshot
+ * 2: snap_src, snap_dest - waiting for handover
+ * 2: snap_src, NULL - handed over, waiting for old to be deleted
+ * 1: NULL, snap_dest - source got destroyed without handover
+ */
+static int __find_snapshots_sharing_cow(struct dm_snapshot *snap,
+ struct dm_snapshot **snap_src,
+ struct dm_snapshot **snap_dest,
+ struct dm_snapshot **snap_merge)
+{
+ struct dm_snapshot *s;
+ struct origin *o;
+ int count = 0;
+ int active;
+
+ o = __lookup_origin(snap->origin->bdev);
+ if (!o)
+ goto out;
+
+ list_for_each_entry(s, &o->snapshots, list) {
+ if (dm_target_is_snapshot_merge(s->ti) && snap_merge)
+ *snap_merge = s;
+ if (!bdev_equal(s->cow->bdev, snap->cow->bdev))
+ continue;
+
+ down_read(&s->lock);
+ active = s->active;
+ up_read(&s->lock);
+
+ if (active) {
+ if (snap_src)
+ *snap_src = s;
+ } else if (snap_dest)
+ *snap_dest = s;
+
+ count++;
+ }
+
+out:
+ return count;
+}
+
+/*
+ * On success, returns 1 if this snapshot is a handover destination,
+ * otherwise returns 0.
+ */
+static int __validate_exception_handover(struct dm_snapshot *snap)
+{
+ struct dm_snapshot *snap_src = NULL, *snap_dest = NULL;
+ struct dm_snapshot *snap_merge = NULL;
+
+ /* Does snapshot need exceptions handed over to it? */
+ if ((__find_snapshots_sharing_cow(snap, &snap_src, &snap_dest,
+ &snap_merge) == 2) ||
+ snap_dest) {
+ snap->ti->error = "Snapshot cow pairing for exception "
+ "table handover failed";
+ return -EINVAL;
+ }
+
+ /*
+ * If no snap_src was found, snap cannot become a handover
+ * destination.
+ */
+ if (!snap_src)
+ return 0;
+
+ /*
+ * Non-snapshot-merge handover?
+ */
+ if (!dm_target_is_snapshot_merge(snap->ti))
+ return 1;
+
+ /*
+ * Do not allow more than one merging snapshot.
+ */
+ if (snap_merge) {
+ snap->ti->error = "A snapshot is already merging.";
+ return -EINVAL;
+ }
+
+ if (!snap_src->store->type->prepare_merge ||
+ !snap_src->store->type->commit_merge) {
+ snap->ti->error = "Snapshot exception store does not "
+ "support snapshot-merge.";
+ return -EINVAL;
+ }
+
+ return 1;
+}
+
+static void __insert_snapshot(struct origin *o, struct dm_snapshot *s)
+{
+ struct dm_snapshot *l;
+
+ /* Sort the list according to chunk size, largest-first smallest-last */
+ list_for_each_entry(l, &o->snapshots, list)
+ if (l->store->chunk_size < s->store->chunk_size)
+ break;
+ list_add_tail(&s->list, &l->list);
+}
+
+/*
* Make a note of the snapshot and its origin so we can look it
* up when the origin has a write on it.
+ *
+ * Also validate snapshot exception store handovers.
+ * On success, returns 1 if this registration is a handover destination,
+ * otherwise returns 0.
*/
static int register_snapshot(struct dm_snapshot *snap)
{
- struct dm_snapshot *l;
- struct origin *o, *new_o;
+ struct origin *o, *new_o = NULL;
struct block_device *bdev = snap->origin->bdev;
+ int r = 0;
new_o = kmalloc(sizeof(*new_o), GFP_KERNEL);
if (!new_o)
return -ENOMEM;
down_write(&_origins_lock);
- o = __lookup_origin(bdev);
+ r = __validate_exception_handover(snap);
+ if (r < 0) {
+ kfree(new_o);
+ goto out;
+ }
+
+ o = __lookup_origin(bdev);
if (o)
kfree(new_o);
else {
@@ -320,14 +491,27 @@ static int register_snapshot(struct dm_snapshot *snap)
__insert_origin(o);
}
- /* Sort the list according to chunk size, largest-first smallest-last */
- list_for_each_entry(l, &o->snapshots, list)
- if (l->store->chunk_size < snap->store->chunk_size)
- break;
- list_add_tail(&snap->list, &l->list);
+ __insert_snapshot(o, snap);
+
+out:
+ up_write(&_origins_lock);
+
+ return r;
+}
+
+/*
+ * Move snapshot to correct place in list according to chunk size.
+ */
+static void reregister_snapshot(struct dm_snapshot *s)
+{
+ struct block_device *bdev = s->origin->bdev;
+
+ down_write(&_origins_lock);
+
+ list_del(&s->list);
+ __insert_snapshot(__lookup_origin(bdev), s);
up_write(&_origins_lock);
- return 0;
}
static void unregister_snapshot(struct dm_snapshot *s)
@@ -338,7 +522,7 @@ static void unregister_snapshot(struct dm_snapshot *s)
o = __lookup_origin(s->origin->bdev);
list_del(&s->list);
- if (list_empty(&o->snapshots)) {
+ if (o && list_empty(&o->snapshots)) {
list_del(&o->hash_list);
kfree(o);
}
@@ -351,8 +535,8 @@ static void unregister_snapshot(struct dm_snapshot *s)
* The lowest hash_shift bits of the chunk number are ignored, allowing
* some consecutive chunks to be grouped together.
*/
-static int init_exception_table(struct exception_table *et, uint32_t size,
- unsigned hash_shift)
+static int dm_exception_table_init(struct dm_exception_table *et,
+ uint32_t size, unsigned hash_shift)
{
unsigned int i;
@@ -368,10 +552,11 @@ static int init_exception_table(struct exception_table *et, uint32_t size,
return 0;
}
-static void exit_exception_table(struct exception_table *et, struct kmem_cache *mem)
+static void dm_exception_table_exit(struct dm_exception_table *et,
+ struct kmem_cache *mem)
{
struct list_head *slot;
- struct dm_snap_exception *ex, *next;
+ struct dm_exception *ex, *next;
int i, size;
size = et->hash_mask + 1;
@@ -385,19 +570,12 @@ static void exit_exception_table(struct exception_table *et, struct kmem_cache *
vfree(et->table);
}
-static uint32_t exception_hash(struct exception_table *et, chunk_t chunk)
+static uint32_t exception_hash(struct dm_exception_table *et, chunk_t chunk)
{
return (chunk >> et->hash_shift) & et->hash_mask;
}
-static void insert_exception(struct exception_table *eh,
- struct dm_snap_exception *e)
-{
- struct list_head *l = &eh->table[exception_hash(eh, e->old_chunk)];
- list_add(&e->hash_list, l);
-}
-
-static void remove_exception(struct dm_snap_exception *e)
+static void dm_remove_exception(struct dm_exception *e)
{
list_del(&e->hash_list);
}
@@ -406,11 +584,11 @@ static void remove_exception(struct dm_snap_exception *e)
* Return the exception data for a sector, or NULL if not
* remapped.
*/
-static struct dm_snap_exception *lookup_exception(struct exception_table *et,
- chunk_t chunk)
+static struct dm_exception *dm_lookup_exception(struct dm_exception_table *et,
+ chunk_t chunk)
{
struct list_head *slot;
- struct dm_snap_exception *e;
+ struct dm_exception *e;
slot = &et->table[exception_hash(et, chunk)];
list_for_each_entry (e, slot, hash_list)
@@ -421,9 +599,9 @@ static struct dm_snap_exception *lookup_exception(struct exception_table *et,
return NULL;
}
-static struct dm_snap_exception *alloc_exception(void)
+static struct dm_exception *alloc_completed_exception(void)
{
- struct dm_snap_exception *e;
+ struct dm_exception *e;
e = kmem_cache_alloc(exception_cache, GFP_NOIO);
if (!e)
@@ -432,7 +610,7 @@ static struct dm_snap_exception *alloc_exception(void)
return e;
}
-static void free_exception(struct dm_snap_exception *e)
+static void free_completed_exception(struct dm_exception *e)
{
kmem_cache_free(exception_cache, e);
}
@@ -457,12 +635,11 @@ static void free_pending_exception(struct dm_snap_pending_exception *pe)
atomic_dec(&s->pending_exceptions_count);
}
-static void insert_completed_exception(struct dm_snapshot *s,
- struct dm_snap_exception *new_e)
+static void dm_insert_exception(struct dm_exception_table *eh,
+ struct dm_exception *new_e)
{
- struct exception_table *eh = &s->complete;
struct list_head *l;
- struct dm_snap_exception *e = NULL;
+ struct dm_exception *e = NULL;
l = &eh->table[exception_hash(eh, new_e->old_chunk)];
@@ -478,7 +655,7 @@ static void insert_completed_exception(struct dm_snapshot *s,
new_e->new_chunk == (dm_chunk_number(e->new_chunk) +
dm_consecutive_chunk_count(e) + 1)) {
dm_consecutive_chunk_count_inc(e);
- free_exception(new_e);
+ free_completed_exception(new_e);
return;
}
@@ -488,7 +665,7 @@ static void insert_completed_exception(struct dm_snapshot *s,
dm_consecutive_chunk_count_inc(e);
e->old_chunk--;
e->new_chunk--;
- free_exception(new_e);
+ free_completed_exception(new_e);
return;
}
@@ -507,9 +684,9 @@ out:
static int dm_add_exception(void *context, chunk_t old, chunk_t new)
{
struct dm_snapshot *s = context;
- struct dm_snap_exception *e;
+ struct dm_exception *e;
- e = alloc_exception();
+ e = alloc_completed_exception();
if (!e)
return -ENOMEM;
@@ -518,11 +695,30 @@ static int dm_add_exception(void *context, chunk_t old, chunk_t new)
/* Consecutive_count is implicitly initialised to zero */
e->new_chunk = new;
- insert_completed_exception(s, e);
+ dm_insert_exception(&s->complete, e);
return 0;
}
+#define min_not_zero(l, r) (((l) == 0) ? (r) : (((r) == 0) ? (l) : min(l, r)))
+
+/*
+ * Return a minimum chunk size of all snapshots that have the specified origin.
+ * Return zero if the origin has no snapshots.
+ */
+static sector_t __minimum_chunk_size(struct origin *o)
+{
+ struct dm_snapshot *snap;
+ unsigned chunk_size = 0;
+
+ if (o)
+ list_for_each_entry(snap, &o->snapshots, list)
+ chunk_size = min_not_zero(chunk_size,
+ snap->store->chunk_size);
+
+ return chunk_size;
+}
+
/*
* Hard coded magic.
*/
@@ -546,16 +742,18 @@ static int init_hash_tables(struct dm_snapshot *s)
* Calculate based on the size of the original volume or
* the COW volume...
*/
- cow_dev_size = get_dev_size(s->store->cow->bdev);
+ cow_dev_size = get_dev_size(s->cow->bdev);
origin_dev_size = get_dev_size(s->origin->bdev);
max_buckets = calc_max_buckets();
hash_size = min(origin_dev_size, cow_dev_size) >> s->store->chunk_shift;
hash_size = min(hash_size, max_buckets);
+ if (hash_size < 64)
+ hash_size = 64;
hash_size = rounddown_pow_of_two(hash_size);
- if (init_exception_table(&s->complete, hash_size,
- DM_CHUNK_CONSECUTIVE_BITS))
+ if (dm_exception_table_init(&s->complete, hash_size,
+ DM_CHUNK_CONSECUTIVE_BITS))
return -ENOMEM;
/*
@@ -566,14 +764,284 @@ static int init_hash_tables(struct dm_snapshot *s)
if (hash_size < 64)
hash_size = 64;
- if (init_exception_table(&s->pending, hash_size, 0)) {
- exit_exception_table(&s->complete, exception_cache);
+ if (dm_exception_table_init(&s->pending, hash_size, 0)) {
+ dm_exception_table_exit(&s->complete, exception_cache);
return -ENOMEM;
}
return 0;
}
+static void merge_shutdown(struct dm_snapshot *s)
+{
+ clear_bit_unlock(RUNNING_MERGE, &s->state_bits);
+ smp_mb__after_clear_bit();
+ wake_up_bit(&s->state_bits, RUNNING_MERGE);
+}
+
+static struct bio *__release_queued_bios_after_merge(struct dm_snapshot *s)
+{
+ s->first_merging_chunk = 0;
+ s->num_merging_chunks = 0;
+
+ return bio_list_get(&s->bios_queued_during_merge);
+}
+
+/*
+ * Remove one chunk from the index of completed exceptions.
+ */
+static int __remove_single_exception_chunk(struct dm_snapshot *s,
+ chunk_t old_chunk)
+{
+ struct dm_exception *e;
+
+ e = dm_lookup_exception(&s->complete, old_chunk);
+ if (!e) {
+ DMERR("Corruption detected: exception for block %llu is "
+ "on disk but not in memory",
+ (unsigned long long)old_chunk);
+ return -EINVAL;
+ }
+
+ /*
+ * If this is the only chunk using this exception, remove exception.
+ */
+ if (!dm_consecutive_chunk_count(e)) {
+ dm_remove_exception(e);
+ free_completed_exception(e);
+ return 0;
+ }
+
+ /*
+ * The chunk may be either at the beginning or the end of a
+ * group of consecutive chunks - never in the middle. We are
+ * removing chunks in the opposite order to that in which they
+ * were added, so this should always be true.
+ * Decrement the consecutive chunk counter and adjust the
+ * starting point if necessary.
+ */
+ if (old_chunk == e->old_chunk) {
+ e->old_chunk++;
+ e->new_chunk++;
+ } else if (old_chunk != e->old_chunk +
+ dm_consecutive_chunk_count(e)) {
+ DMERR("Attempt to merge block %llu from the "
+ "middle of a chunk range [%llu - %llu]",
+ (unsigned long long)old_chunk,
+ (unsigned long long)e->old_chunk,
+ (unsigned long long)
+ e->old_chunk + dm_consecutive_chunk_count(e));
+ return -EINVAL;
+ }
+
+ dm_consecutive_chunk_count_dec(e);
+
+ return 0;
+}
+
+static void flush_bios(struct bio *bio);
+
+static int remove_single_exception_chunk(struct dm_snapshot *s)
+{
+ struct bio *b = NULL;
+ int r;
+ chunk_t old_chunk = s->first_merging_chunk + s->num_merging_chunks - 1;
+
+ down_write(&s->lock);
+
+ /*
+ * Process chunks (and associated exceptions) in reverse order
+ * so that dm_consecutive_chunk_count_dec() accounting works.
+ */
+ do {
+ r = __remove_single_exception_chunk(s, old_chunk);
+ if (r)
+ goto out;
+ } while (old_chunk-- > s->first_merging_chunk);
+
+ b = __release_queued_bios_after_merge(s);
+
+out:
+ up_write(&s->lock);
+ if (b)
+ flush_bios(b);
+
+ return r;
+}
+
+static int origin_write_extent(struct dm_snapshot *merging_snap,
+ sector_t sector, unsigned chunk_size);
+
+static void merge_callback(int read_err, unsigned long write_err,
+ void *context);
+
+static uint64_t read_pending_exceptions_done_count(void)
+{
+ uint64_t pending_exceptions_done;
+
+ spin_lock(&_pending_exceptions_done_spinlock);
+ pending_exceptions_done = _pending_exceptions_done_count;
+ spin_unlock(&_pending_exceptions_done_spinlock);
+
+ return pending_exceptions_done;
+}
+
+static void increment_pending_exceptions_done_count(void)
+{
+ spin_lock(&_pending_exceptions_done_spinlock);
+ _pending_exceptions_done_count++;
+ spin_unlock(&_pending_exceptions_done_spinlock);
+
+ wake_up_all(&_pending_exceptions_done);
+}
+
+static void snapshot_merge_next_chunks(struct dm_snapshot *s)
+{
+ int i, linear_chunks;
+ chunk_t old_chunk, new_chunk;
+ struct dm_io_region src, dest;
+ sector_t io_size;
+ uint64_t previous_count;
+
+ BUG_ON(!test_bit(RUNNING_MERGE, &s->state_bits));
+ if (unlikely(test_bit(SHUTDOWN_MERGE, &s->state_bits)))
+ goto shut;
+
+ /*
+ * valid flag never changes during merge, so no lock required.
+ */
+ if (!s->valid) {
+ DMERR("Snapshot is invalid: can't merge");
+ goto shut;
+ }
+
+ linear_chunks = s->store->type->prepare_merge(s->store, &old_chunk,
+ &new_chunk);
+ if (linear_chunks <= 0) {
+ if (linear_chunks < 0) {
+ DMERR("Read error in exception store: "
+ "shutting down merge");
+ down_write(&s->lock);
+ s->merge_failed = 1;
+ up_write(&s->lock);
+ }
+ goto shut;
+ }
+
+ /* Adjust old_chunk and new_chunk to reflect start of linear region */
+ old_chunk = old_chunk + 1 - linear_chunks;
+ new_chunk = new_chunk + 1 - linear_chunks;
+
+ /*
+ * Use one (potentially large) I/O to copy all 'linear_chunks'
+ * from the exception store to the origin
+ */
+ io_size = linear_chunks * s->store->chunk_size;
+
+ dest.bdev = s->origin->bdev;
+ dest.sector = chunk_to_sector(s->store, old_chunk);
+ dest.count = min(io_size, get_dev_size(dest.bdev) - dest.sector);
+
+ src.bdev = s->cow->bdev;
+ src.sector = chunk_to_sector(s->store, new_chunk);
+ src.count = dest.count;
+
+ /*
+ * Reallocate any exceptions needed in other snapshots then
+ * wait for the pending exceptions to complete.
+ * Each time any pending exception (globally on the system)
+ * completes we are woken and repeat the process to find out
+ * if we can proceed. While this may not seem a particularly
+ * efficient algorithm, it is not expected to have any
+ * significant impact on performance.
+ */
+ previous_count = read_pending_exceptions_done_count();
+ while (origin_write_extent(s, dest.sector, io_size)) {
+ wait_event(_pending_exceptions_done,
+ (read_pending_exceptions_done_count() !=
+ previous_count));
+ /* Retry after the wait, until all exceptions are done. */
+ previous_count = read_pending_exceptions_done_count();
+ }
+
+ down_write(&s->lock);
+ s->first_merging_chunk = old_chunk;
+ s->num_merging_chunks = linear_chunks;
+ up_write(&s->lock);
+
+ /* Wait until writes to all 'linear_chunks' drain */
+ for (i = 0; i < linear_chunks; i++)
+ __check_for_conflicting_io(s, old_chunk + i);
+
+ dm_kcopyd_copy(s->kcopyd_client, &src, 1, &dest, 0, merge_callback, s);
+ return;
+
+shut:
+ merge_shutdown(s);
+}
+
+static void error_bios(struct bio *bio);
+
+static void merge_callback(int read_err, unsigned long write_err, void *context)
+{
+ struct dm_snapshot *s = context;
+ struct bio *b = NULL;
+
+ if (read_err || write_err) {
+ if (read_err)
+ DMERR("Read error: shutting down merge.");
+ else
+ DMERR("Write error: shutting down merge.");
+ goto shut;
+ }
+
+ if (s->store->type->commit_merge(s->store,
+ s->num_merging_chunks) < 0) {
+ DMERR("Write error in exception store: shutting down merge");
+ goto shut;
+ }
+
+ if (remove_single_exception_chunk(s) < 0)
+ goto shut;
+
+ snapshot_merge_next_chunks(s);
+
+ return;
+
+shut:
+ down_write(&s->lock);
+ s->merge_failed = 1;
+ b = __release_queued_bios_after_merge(s);
+ up_write(&s->lock);
+ error_bios(b);
+
+ merge_shutdown(s);
+}
+
+static void start_merge(struct dm_snapshot *s)
+{
+ if (!test_and_set_bit(RUNNING_MERGE, &s->state_bits))
+ snapshot_merge_next_chunks(s);
+}
+
+static int wait_schedule(void *ptr)
+{
+ schedule();
+
+ return 0;
+}
+
+/*
+ * Stop the merging process and wait until it finishes.
+ */
+static void stop_merge(struct dm_snapshot *s)
+{
+ set_bit(SHUTDOWN_MERGE, &s->state_bits);
+ wait_on_bit(&s->state_bits, RUNNING_MERGE, wait_schedule,
+ TASK_UNINTERRUPTIBLE);
+ clear_bit(SHUTDOWN_MERGE, &s->state_bits);
+}
+
/*
* Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size>
*/
@@ -582,50 +1050,73 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
struct dm_snapshot *s;
int i;
int r = -EINVAL;
- char *origin_path;
- struct dm_exception_store *store;
- unsigned args_used;
+ char *origin_path, *cow_path;
+ unsigned args_used, num_flush_requests = 1;
+ fmode_t origin_mode = FMODE_READ;
if (argc != 4) {
ti->error = "requires exactly 4 arguments";
r = -EINVAL;
- goto bad_args;
+ goto bad;
+ }
+
+ if (dm_target_is_snapshot_merge(ti)) {
+ num_flush_requests = 2;
+ origin_mode = FMODE_WRITE;
}
origin_path = argv[0];
argv++;
argc--;
- r = dm_exception_store_create(ti, argc, argv, &args_used, &store);
+ s = kmalloc(sizeof(*s), GFP_KERNEL);
+ if (!s) {
+ ti->error = "Cannot allocate snapshot context private "
+ "structure";
+ r = -ENOMEM;
+ goto bad;
+ }
+
+ cow_path = argv[0];
+ argv++;
+ argc--;
+
+ r = dm_get_device(ti, cow_path, 0, 0,
+ FMODE_READ | FMODE_WRITE, &s->cow);
+ if (r) {
+ ti->error = "Cannot get COW device";
+ goto bad_cow;
+ }
+
+ r = dm_exception_store_create(ti, argc, argv, s, &args_used, &s->store);
if (r) {
ti->error = "Couldn't create exception store";
r = -EINVAL;
- goto bad_args;
+ goto bad_store;
}
argv += args_used;
argc -= args_used;
- s = kmalloc(sizeof(*s), GFP_KERNEL);
- if (!s) {
- ti->error = "Cannot allocate snapshot context private "
- "structure";
- r = -ENOMEM;
- goto bad_snap;
- }
-
- r = dm_get_device(ti, origin_path, 0, ti->len, FMODE_READ, &s->origin);
+ r = dm_get_device(ti, origin_path, 0, ti->len, origin_mode, &s->origin);
if (r) {
ti->error = "Cannot get origin device";
goto bad_origin;
}
- s->store = store;
+ s->ti = ti;
s->valid = 1;
s->active = 0;
+ s->suspended = 0;
atomic_set(&s->pending_exceptions_count, 0);
init_rwsem(&s->lock);
+ INIT_LIST_HEAD(&s->list);
spin_lock_init(&s->pe_lock);
+ s->state_bits = 0;
+ s->merge_failed = 0;
+ s->first_merging_chunk = 0;
+ s->num_merging_chunks = 0;
+ bio_list_init(&s->bios_queued_during_merge);
/* Allocate hash table for COW data */
if (init_hash_tables(s)) {
@@ -659,39 +1150,55 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
spin_lock_init(&s->tracked_chunk_lock);
- /* Metadata must only be loaded into one table at once */
+ bio_list_init(&s->queued_bios);
+ INIT_WORK(&s->queued_bios_work, flush_queued_bios);
+
+ ti->private = s;
+ ti->num_flush_requests = num_flush_requests;
+
+ /* Add snapshot to the list of snapshots for this origin */
+ /* Exceptions aren't triggered till snapshot_resume() is called */
+ r = register_snapshot(s);
+ if (r == -ENOMEM) {
+ ti->error = "Snapshot origin struct allocation failed";
+ goto bad_load_and_register;
+ } else if (r < 0) {
+ /* invalid handover, register_snapshot has set ti->error */
+ goto bad_load_and_register;
+ }
+
+ /*
+ * Metadata must only be loaded into one table at once, so skip this
+ * if metadata will be handed over during resume.
+ * Chunk size will be set during the handover - set it to zero to
+ * ensure it's ignored.
+ */
+ if (r > 0) {
+ s->store->chunk_size = 0;
+ return 0;
+ }
+
r = s->store->type->read_metadata(s->store, dm_add_exception,
(void *)s);
if (r < 0) {
ti->error = "Failed to read snapshot metadata";
- goto bad_load_and_register;
+ goto bad_read_metadata;
} else if (r > 0) {
s->valid = 0;
DMWARN("Snapshot is marked invalid.");
}
- bio_list_init(&s->queued_bios);
- INIT_WORK(&s->queued_bios_work, flush_queued_bios);
-
if (!s->store->chunk_size) {
ti->error = "Chunk size not set";
- goto bad_load_and_register;
- }
-
- /* Add snapshot to the list of snapshots for this origin */
- /* Exceptions aren't triggered till snapshot_resume() is called */
- if (register_snapshot(s)) {
- r = -EINVAL;
- ti->error = "Cannot register snapshot origin";
- goto bad_load_and_register;
+ goto bad_read_metadata;
}
-
- ti->private = s;
ti->split_io = s->store->chunk_size;
- ti->num_flush_requests = 1;
return 0;
+bad_read_metadata:
+ unregister_snapshot(s);
+
bad_load_and_register:
mempool_destroy(s->tracked_chunk_pool);
@@ -702,19 +1209,22 @@ bad_pending_pool:
dm_kcopyd_client_destroy(s->kcopyd_client);
bad_kcopyd:
- exit_exception_table(&s->pending, pending_cache);
- exit_exception_table(&s->complete, exception_cache);
+ dm_exception_table_exit(&s->pending, pending_cache);
+ dm_exception_table_exit(&s->complete, exception_cache);
bad_hash_tables:
dm_put_device(ti, s->origin);
bad_origin:
- kfree(s);
+ dm_exception_store_destroy(s->store);
-bad_snap:
- dm_exception_store_destroy(store);
+bad_store:
+ dm_put_device(ti, s->cow);
+
+bad_cow:
+ kfree(s);
-bad_args:
+bad:
return r;
}
@@ -723,8 +1233,39 @@ static void __free_exceptions(struct dm_snapshot *s)
dm_kcopyd_client_destroy(s->kcopyd_client);
s->kcopyd_client = NULL;
- exit_exception_table(&s->pending, pending_cache);
- exit_exception_table(&s->complete, exception_cache);
+ dm_exception_table_exit(&s->pending, pending_cache);
+ dm_exception_table_exit(&s->complete, exception_cache);
+}
+
+static void __handover_exceptions(struct dm_snapshot *snap_src,
+ struct dm_snapshot *snap_dest)
+{
+ union {
+ struct dm_exception_table table_swap;
+ struct dm_exception_store *store_swap;
+ } u;
+
+ /*
+ * Swap all snapshot context information between the two instances.
+ */
+ u.table_swap = snap_dest->complete;
+ snap_dest->complete = snap_src->complete;
+ snap_src->complete = u.table_swap;
+
+ u.store_swap = snap_dest->store;
+ snap_dest->store = snap_src->store;
+ snap_src->store = u.store_swap;
+
+ snap_dest->store->snap = snap_dest;
+ snap_src->store->snap = snap_src;
+
+ snap_dest->ti->split_io = snap_dest->store->chunk_size;
+ snap_dest->valid = snap_src->valid;
+
+ /*
+ * Set source invalid to ensure it receives no further I/O.
+ */
+ snap_src->valid = 0;
}
static void snapshot_dtr(struct dm_target *ti)
@@ -733,9 +1274,24 @@ static void snapshot_dtr(struct dm_target *ti)
int i;
#endif
struct dm_snapshot *s = ti->private;
+ struct dm_snapshot *snap_src = NULL, *snap_dest = NULL;
flush_workqueue(ksnapd);
+ down_read(&_origins_lock);
+ /* Check whether exception handover must be cancelled */
+ (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL);
+ if (snap_src && snap_dest && (s == snap_src)) {
+ down_write(&snap_dest->lock);
+ snap_dest->valid = 0;
+ up_write(&snap_dest->lock);
+ DMERR("Cancelling snapshot handover.");
+ }
+ up_read(&_origins_lock);
+
+ if (dm_target_is_snapshot_merge(ti))
+ stop_merge(s);
+
/* Prevent further origin writes from using this snapshot. */
/* After this returns there can be no new kcopyd jobs. */
unregister_snapshot(s);
@@ -763,6 +1319,8 @@ static void snapshot_dtr(struct dm_target *ti)
dm_exception_store_destroy(s->store);
+ dm_put_device(ti, s->cow);
+
kfree(s);
}
@@ -795,6 +1353,26 @@ static void flush_queued_bios(struct work_struct *work)
flush_bios(queued_bios);
}
+static int do_origin(struct dm_dev *origin, struct bio *bio);
+
+/*
+ * Flush a list of buffers.
+ */
+static void retry_origin_bios(struct dm_snapshot *s, struct bio *bio)
+{
+ struct bio *n;
+ int r;
+
+ while (bio) {
+ n = bio->bi_next;
+ bio->bi_next = NULL;
+ r = do_origin(s->origin, bio);
+ if (r == DM_MAPIO_REMAPPED)
+ generic_make_request(bio);
+ bio = n;
+ }
+}
+
/*
* Error a list of buffers.
*/
@@ -825,45 +1403,12 @@ static void __invalidate_snapshot(struct dm_snapshot *s, int err)
s->valid = 0;
- dm_table_event(s->store->ti->table);
-}
-
-static void get_pending_exception(struct dm_snap_pending_exception *pe)
-{
- atomic_inc(&pe->ref_count);
-}
-
-static struct bio *put_pending_exception(struct dm_snap_pending_exception *pe)
-{
- struct dm_snap_pending_exception *primary_pe;
- struct bio *origin_bios = NULL;
-
- primary_pe = pe->primary_pe;
-
- /*
- * If this pe is involved in a write to the origin and
- * it is the last sibling to complete then release
- * the bios for the original write to the origin.
- */
- if (primary_pe &&
- atomic_dec_and_test(&primary_pe->ref_count)) {
- origin_bios = bio_list_get(&primary_pe->origin_bios);
- free_pending_exception(primary_pe);
- }
-
- /*
- * Free the pe if it's not linked to an origin write or if
- * it's not itself a primary pe.
- */
- if (!primary_pe || primary_pe != pe)
- free_pending_exception(pe);
-
- return origin_bios;
+ dm_table_event(s->ti->table);
}
static void pending_complete(struct dm_snap_pending_exception *pe, int success)
{
- struct dm_snap_exception *e;
+ struct dm_exception *e;
struct dm_snapshot *s = pe->snap;
struct bio *origin_bios = NULL;
struct bio *snapshot_bios = NULL;
@@ -877,7 +1422,7 @@ static void pending_complete(struct dm_snap_pending_exception *pe, int success)
goto out;
}
- e = alloc_exception();
+ e = alloc_completed_exception();
if (!e) {
down_write(&s->lock);
__invalidate_snapshot(s, -ENOMEM);
@@ -888,28 +1433,27 @@ static void pending_complete(struct dm_snap_pending_exception *pe, int success)
down_write(&s->lock);
if (!s->valid) {
- free_exception(e);
+ free_completed_exception(e);
error = 1;
goto out;
}
- /*
- * Check for conflicting reads. This is extremely improbable,
- * so msleep(1) is sufficient and there is no need for a wait queue.
- */
- while (__chunk_is_tracked(s, pe->e.old_chunk))
- msleep(1);
+ /* Check for conflicting reads */
+ __check_for_conflicting_io(s, pe->e.old_chunk);
/*
* Add a proper exception, and remove the
* in-flight exception from the list.
*/
- insert_completed_exception(s, e);
+ dm_insert_exception(&s->complete, e);
out:
- remove_exception(&pe->e);
+ dm_remove_exception(&pe->e);
snapshot_bios = bio_list_get(&pe->snapshot_bios);
- origin_bios = put_pending_exception(pe);
+ origin_bios = bio_list_get(&pe->origin_bios);
+ free_pending_exception(pe);
+
+ increment_pending_exceptions_done_count();
up_write(&s->lock);
@@ -919,7 +1463,7 @@ static void pending_complete(struct dm_snap_pending_exception *pe, int success)
else
flush_bios(snapshot_bios);
- flush_bios(origin_bios);
+ retry_origin_bios(s, origin_bios);
}
static void commit_callback(void *context, int success)
@@ -963,7 +1507,7 @@ static void start_copy(struct dm_snap_pending_exception *pe)
src.sector = chunk_to_sector(s->store, pe->e.old_chunk);
src.count = min((sector_t)s->store->chunk_size, dev_size - src.sector);
- dest.bdev = s->store->cow->bdev;
+ dest.bdev = s->cow->bdev;
dest.sector = chunk_to_sector(s->store, pe->e.new_chunk);
dest.count = src.count;
@@ -975,7 +1519,7 @@ static void start_copy(struct dm_snap_pending_exception *pe)
static struct dm_snap_pending_exception *
__lookup_pending_exception(struct dm_snapshot *s, chunk_t chunk)
{
- struct dm_snap_exception *e = lookup_exception(&s->pending, chunk);
+ struct dm_exception *e = dm_lookup_exception(&s->pending, chunk);
if (!e)
return NULL;
@@ -1006,8 +1550,6 @@ __find_pending_exception(struct dm_snapshot *s,
pe->e.old_chunk = chunk;
bio_list_init(&pe->origin_bios);
bio_list_init(&pe->snapshot_bios);
- pe->primary_pe = NULL;
- atomic_set(&pe->ref_count, 0);
pe->started = 0;
if (s->store->type->prepare_exception(s->store, &pe->e)) {
@@ -1015,16 +1557,15 @@ __find_pending_exception(struct dm_snapshot *s,
return NULL;
}
- get_pending_exception(pe);
- insert_exception(&s->pending, &pe->e);
+ dm_insert_exception(&s->pending, &pe->e);
return pe;
}
-static void remap_exception(struct dm_snapshot *s, struct dm_snap_exception *e,
+static void remap_exception(struct dm_snapshot *s, struct dm_exception *e,
struct bio *bio, chunk_t chunk)
{
- bio->bi_bdev = s->store->cow->bdev;
+ bio->bi_bdev = s->cow->bdev;
bio->bi_sector = chunk_to_sector(s->store,
dm_chunk_number(e->new_chunk) +
(chunk - e->old_chunk)) +
@@ -1035,14 +1576,14 @@ static void remap_exception(struct dm_snapshot *s, struct dm_snap_exception *e,
static int snapshot_map(struct dm_target *ti, struct bio *bio,
union map_info *map_context)
{
- struct dm_snap_exception *e;
+ struct dm_exception *e;
struct dm_snapshot *s = ti->private;
int r = DM_MAPIO_REMAPPED;
chunk_t chunk;
struct dm_snap_pending_exception *pe = NULL;
if (unlikely(bio_empty_barrier(bio))) {
- bio->bi_bdev = s->store->cow->bdev;
+ bio->bi_bdev = s->cow->bdev;
return DM_MAPIO_REMAPPED;
}
@@ -1063,7 +1604,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
}
/* If the block is already remapped - use that, else remap it */
- e = lookup_exception(&s->complete, chunk);
+ e = dm_lookup_exception(&s->complete, chunk);
if (e) {
remap_exception(s, e, bio, chunk);
goto out_unlock;
@@ -1087,7 +1628,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
goto out_unlock;
}
- e = lookup_exception(&s->complete, chunk);
+ e = dm_lookup_exception(&s->complete, chunk);
if (e) {
free_pending_exception(pe);
remap_exception(s, e, bio, chunk);
@@ -1125,6 +1666,78 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
return r;
}
+/*
+ * A snapshot-merge target behaves like a combination of a snapshot
+ * target and a snapshot-origin target. It only generates new
+ * exceptions in other snapshots and not in the one that is being
+ * merged.
+ *
+ * For each chunk, if there is an existing exception, it is used to
+ * redirect I/O to the cow device. Otherwise I/O is sent to the origin,
+ * which in turn might generate exceptions in other snapshots.
+ * If merging is currently taking place on the chunk in question, the
+ * I/O is deferred by adding it to s->bios_queued_during_merge.
+ */
+static int snapshot_merge_map(struct dm_target *ti, struct bio *bio,
+ union map_info *map_context)
+{
+ struct dm_exception *e;
+ struct dm_snapshot *s = ti->private;
+ int r = DM_MAPIO_REMAPPED;
+ chunk_t chunk;
+
+ if (unlikely(bio_empty_barrier(bio))) {
+ if (!map_context->flush_request)
+ bio->bi_bdev = s->origin->bdev;
+ else
+ bio->bi_bdev = s->cow->bdev;
+ map_context->ptr = NULL;
+ return DM_MAPIO_REMAPPED;
+ }
+
+ chunk = sector_to_chunk(s->store, bio->bi_sector);
+
+ down_write(&s->lock);
+
+ /* Full merging snapshots are redirected to the origin */
+ if (!s->valid)
+ goto redirect_to_origin;
+
+ /* If the block is already remapped - use that */
+ e = dm_lookup_exception(&s->complete, chunk);
+ if (e) {
+ /* Queue writes overlapping with chunks being merged */
+ if (bio_rw(bio) == WRITE &&
+ chunk >= s->first_merging_chunk &&
+ chunk < (s->first_merging_chunk +
+ s->num_merging_chunks)) {
+ bio->bi_bdev = s->origin->bdev;
+ bio_list_add(&s->bios_queued_during_merge, bio);
+ r = DM_MAPIO_SUBMITTED;
+ goto out_unlock;
+ }
+
+ remap_exception(s, e, bio, chunk);
+
+ if (bio_rw(bio) == WRITE)
+ map_context->ptr = track_chunk(s, chunk);
+ goto out_unlock;
+ }
+
+redirect_to_origin:
+ bio->bi_bdev = s->origin->bdev;
+
+ if (bio_rw(bio) == WRITE) {
+ up_write(&s->lock);
+ return do_origin(s->origin, bio);
+ }
+
+out_unlock:
+ up_write(&s->lock);
+
+ return r;
+}
+
static int snapshot_end_io(struct dm_target *ti, struct bio *bio,
int error, union map_info *map_context)
{
@@ -1137,40 +1750,135 @@ static int snapshot_end_io(struct dm_target *ti, struct bio *bio,
return 0;
}
+static void snapshot_merge_presuspend(struct dm_target *ti)
+{
+ struct dm_snapshot *s = ti->private;
+
+ stop_merge(s);
+}
+
+static void snapshot_postsuspend(struct dm_target *ti)
+{
+ struct dm_snapshot *s = ti->private;
+
+ down_write(&s->lock);
+ s->suspended = 1;
+ up_write(&s->lock);
+}
+
+static int snapshot_preresume(struct dm_target *ti)
+{
+ int r = 0;
+ struct dm_snapshot *s = ti->private;
+ struct dm_snapshot *snap_src = NULL, *snap_dest = NULL;
+
+ down_read(&_origins_lock);
+ (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL);
+ if (snap_src && snap_dest) {
+ down_read(&snap_src->lock);
+ if (s == snap_src) {
+ DMERR("Unable to resume snapshot source until "
+ "handover completes.");
+ r = -EINVAL;
+ } else if (!snap_src->suspended) {
+ DMERR("Unable to perform snapshot handover until "
+ "source is suspended.");
+ r = -EINVAL;
+ }
+ up_read(&snap_src->lock);
+ }
+ up_read(&_origins_lock);
+
+ return r;
+}
+
static void snapshot_resume(struct dm_target *ti)
{
struct dm_snapshot *s = ti->private;
+ struct dm_snapshot *snap_src = NULL, *snap_dest = NULL;
+
+ down_read(&_origins_lock);
+ (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL);
+ if (snap_src && snap_dest) {
+ down_write(&snap_src->lock);
+ down_write_nested(&snap_dest->lock, SINGLE_DEPTH_NESTING);
+ __handover_exceptions(snap_src, snap_dest);
+ up_write(&snap_dest->lock);
+ up_write(&snap_src->lock);
+ }
+ up_read(&_origins_lock);
+
+ /* Now we have correct chunk size, reregister */
+ reregister_snapshot(s);
down_write(&s->lock);
s->active = 1;
+ s->suspended = 0;
up_write(&s->lock);
}
+static sector_t get_origin_minimum_chunksize(struct block_device *bdev)
+{
+ sector_t min_chunksize;
+
+ down_read(&_origins_lock);
+ min_chunksize = __minimum_chunk_size(__lookup_origin(bdev));
+ up_read(&_origins_lock);
+
+ return min_chunksize;
+}
+
+static void snapshot_merge_resume(struct dm_target *ti)
+{
+ struct dm_snapshot *s = ti->private;
+
+ /*
+ * Handover exceptions from existing snapshot.
+ */
+ snapshot_resume(ti);
+
+ /*
+ * snapshot-merge acts as an origin, so set ti->split_io
+ */
+ ti->split_io = get_origin_minimum_chunksize(s->origin->bdev);
+
+ start_merge(s);
+}
+
static int snapshot_status(struct dm_target *ti, status_type_t type,
char *result, unsigned int maxlen)
{
unsigned sz = 0;
struct dm_snapshot *snap = ti->private;
- down_write(&snap->lock);
-
switch (type) {
case STATUSTYPE_INFO:
+
+ down_write(&snap->lock);
+
if (!snap->valid)
DMEMIT("Invalid");
+ else if (snap->merge_failed)
+ DMEMIT("Merge failed");
else {
- if (snap->store->type->fraction_full) {
- sector_t numerator, denominator;
- snap->store->type->fraction_full(snap->store,
- &numerator,
- &denominator);
- DMEMIT("%llu/%llu",
- (unsigned long long)numerator,
- (unsigned long long)denominator);
+ if (snap->store->type->usage) {
+ sector_t total_sectors, sectors_allocated,
+ metadata_sectors;
+ snap->store->type->usage(snap->store,
+ &total_sectors,
+ &sectors_allocated,
+ &metadata_sectors);
+ DMEMIT("%llu/%llu %llu",
+ (unsigned long long)sectors_allocated,
+ (unsigned long long)total_sectors,
+ (unsigned long long)metadata_sectors);
}
else
DMEMIT("Unknown");
}
+
+ up_write(&snap->lock);
+
break;
case STATUSTYPE_TABLE:
@@ -1179,14 +1887,12 @@ static int snapshot_status(struct dm_target *ti, status_type_t type,
* to make private copies if the output is to
* make sense.
*/
- DMEMIT("%s", snap->origin->name);
+ DMEMIT("%s %s", snap->origin->name, snap->cow->name);
snap->store->type->status(snap->store, type, result + sz,
maxlen - sz);
break;
}
- up_write(&snap->lock);
-
return 0;
}
@@ -1202,17 +1908,36 @@ static int snapshot_iterate_devices(struct dm_target *ti,
/*-----------------------------------------------------------------
* Origin methods
*---------------------------------------------------------------*/
-static int __origin_write(struct list_head *snapshots, struct bio *bio)
+
+/*
+ * If no exceptions need creating, DM_MAPIO_REMAPPED is returned and any
+ * supplied bio was ignored. The caller may submit it immediately.
+ * (No remapping actually occurs as the origin is always a direct linear
+ * map.)
+ *
+ * If further exceptions are required, DM_MAPIO_SUBMITTED is returned
+ * and any supplied bio is added to a list to be submitted once all
+ * the necessary exceptions exist.
+ */
+static int __origin_write(struct list_head *snapshots, sector_t sector,
+ struct bio *bio)
{
- int r = DM_MAPIO_REMAPPED, first = 0;
+ int r = DM_MAPIO_REMAPPED;
struct dm_snapshot *snap;
- struct dm_snap_exception *e;
- struct dm_snap_pending_exception *pe, *next_pe, *primary_pe = NULL;
+ struct dm_exception *e;
+ struct dm_snap_pending_exception *pe;
+ struct dm_snap_pending_exception *pe_to_start_now = NULL;
+ struct dm_snap_pending_exception *pe_to_start_last = NULL;
chunk_t chunk;
- LIST_HEAD(pe_queue);
/* Do all the snapshots on this origin */
list_for_each_entry (snap, snapshots, list) {
+ /*
+ * Don't make new exceptions in a merging snapshot
+ * because it has effectively been deleted
+ */
+ if (dm_target_is_snapshot_merge(snap->ti))
+ continue;
down_write(&snap->lock);
@@ -1221,24 +1946,21 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio)
goto next_snapshot;
/* Nothing to do if writing beyond end of snapshot */
- if (bio->bi_sector >= dm_table_get_size(snap->store->ti->table))
+ if (sector >= dm_table_get_size(snap->ti->table))
goto next_snapshot;
/*
* Remember, different snapshots can have
* different chunk sizes.
*/
- chunk = sector_to_chunk(snap->store, bio->bi_sector);
+ chunk = sector_to_chunk(snap->store, sector);
/*
* Check exception table to see if block
* is already remapped in this snapshot
* and trigger an exception if not.
- *
- * ref_count is initialised to 1 so pending_complete()
- * won't destroy the primary_pe while we're inside this loop.
*/
- e = lookup_exception(&snap->complete, chunk);
+ e = dm_lookup_exception(&snap->complete, chunk);
if (e)
goto next_snapshot;
@@ -1253,7 +1975,7 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio)
goto next_snapshot;
}
- e = lookup_exception(&snap->complete, chunk);
+ e = dm_lookup_exception(&snap->complete, chunk);
if (e) {
free_pending_exception(pe);
goto next_snapshot;
@@ -1266,59 +1988,43 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio)
}
}
- if (!primary_pe) {
- /*
- * Either every pe here has same
- * primary_pe or none has one yet.
- */
- if (pe->primary_pe)
- primary_pe = pe->primary_pe;
- else {
- primary_pe = pe;
- first = 1;
- }
-
- bio_list_add(&primary_pe->origin_bios, bio);
+ r = DM_MAPIO_SUBMITTED;
- r = DM_MAPIO_SUBMITTED;
- }
+ /*
+ * If an origin bio was supplied, queue it to wait for the
+ * completion of this exception, and start this one last,
+ * at the end of the function.
+ */
+ if (bio) {
+ bio_list_add(&pe->origin_bios, bio);
+ bio = NULL;
- if (!pe->primary_pe) {
- pe->primary_pe = primary_pe;
- get_pending_exception(primary_pe);
+ if (!pe->started) {
+ pe->started = 1;
+ pe_to_start_last = pe;
+ }
}
if (!pe->started) {
pe->started = 1;
- list_add_tail(&pe->list, &pe_queue);
+ pe_to_start_now = pe;
}
next_snapshot:
up_write(&snap->lock);
- }
- if (!primary_pe)
- return r;
-
- /*
- * If this is the first time we're processing this chunk and
- * ref_count is now 1 it means all the pending exceptions
- * got completed while we were in the loop above, so it falls to
- * us here to remove the primary_pe and submit any origin_bios.
- */
-
- if (first && atomic_dec_and_test(&primary_pe->ref_count)) {
- flush_bios(bio_list_get(&primary_pe->origin_bios));
- free_pending_exception(primary_pe);
- /* If we got here, pe_queue is necessarily empty. */
- return r;
+ if (pe_to_start_now) {
+ start_copy(pe_to_start_now);
+ pe_to_start_now = NULL;
+ }
}
/*
- * Now that we have a complete pe list we can start the copying.
+ * Submit the exception against which the bio is queued last,
+ * to give the other exceptions a head start.
*/
- list_for_each_entry_safe(pe, next_pe, &pe_queue, list)
- start_copy(pe);
+ if (pe_to_start_last)
+ start_copy(pe_to_start_last);
return r;
}
@@ -1334,13 +2040,48 @@ static int do_origin(struct dm_dev *origin, struct bio *bio)
down_read(&_origins_lock);
o = __lookup_origin(origin->bdev);
if (o)
- r = __origin_write(&o->snapshots, bio);
+ r = __origin_write(&o->snapshots, bio->bi_sector, bio);
up_read(&_origins_lock);
return r;
}
/*
+ * Trigger exceptions in all non-merging snapshots.
+ *
+ * The chunk size of the merging snapshot may be larger than the chunk
+ * size of some other snapshot so we may need to reallocate multiple
+ * chunks in other snapshots.
+ *
+ * We scan all the overlapping exceptions in the other snapshots.
+ * Returns 1 if anything was reallocated and must be waited for,
+ * otherwise returns 0.
+ *
+ * size must be a multiple of merging_snap's chunk_size.
+ */
+static int origin_write_extent(struct dm_snapshot *merging_snap,
+ sector_t sector, unsigned size)
+{
+ int must_wait = 0;
+ sector_t n;
+ struct origin *o;
+
+ /*
+ * The origin's __minimum_chunk_size() got stored in split_io
+ * by snapshot_merge_resume().
+ */
+ down_read(&_origins_lock);
+ o = __lookup_origin(merging_snap->origin->bdev);
+ for (n = 0; n < size; n += merging_snap->ti->split_io)
+ if (__origin_write(&o->snapshots, sector + n, NULL) ==
+ DM_MAPIO_SUBMITTED)
+ must_wait = 1;
+ up_read(&_origins_lock);
+
+ return must_wait;
+}
+
+/*
* Origin: maps a linear range of a device, with hooks for snapshotting.
*/
@@ -1391,8 +2132,6 @@ static int origin_map(struct dm_target *ti, struct bio *bio,
return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED;
}
-#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
-
/*
* Set the target "split_io" field to the minimum of all the snapshots'
* chunk sizes.
@@ -1400,19 +2139,8 @@ static int origin_map(struct dm_target *ti, struct bio *bio,
static void origin_resume(struct dm_target *ti)
{
struct dm_dev *dev = ti->private;
- struct dm_snapshot *snap;
- struct origin *o;
- unsigned chunk_size = 0;
-
- down_read(&_origins_lock);
- o = __lookup_origin(dev->bdev);
- if (o)
- list_for_each_entry (snap, &o->snapshots, list)
- chunk_size = min_not_zero(chunk_size,
- snap->store->chunk_size);
- up_read(&_origins_lock);
- ti->split_io = chunk_size;
+ ti->split_io = get_origin_minimum_chunksize(dev->bdev);
}
static int origin_status(struct dm_target *ti, status_type_t type, char *result,
@@ -1455,17 +2183,35 @@ static struct target_type origin_target = {
static struct target_type snapshot_target = {
.name = "snapshot",
- .version = {1, 7, 0},
+ .version = {1, 9, 0},
.module = THIS_MODULE,
.ctr = snapshot_ctr,
.dtr = snapshot_dtr,
.map = snapshot_map,
.end_io = snapshot_end_io,
+ .postsuspend = snapshot_postsuspend,
+ .preresume = snapshot_preresume,
.resume = snapshot_resume,
.status = snapshot_status,
.iterate_devices = snapshot_iterate_devices,
};
+static struct target_type merge_target = {
+ .name = dm_snapshot_merge_target_name,
+ .version = {1, 0, 0},
+ .module = THIS_MODULE,
+ .ctr = snapshot_ctr,
+ .dtr = snapshot_dtr,
+ .map = snapshot_merge_map,
+ .end_io = snapshot_end_io,
+ .presuspend = snapshot_merge_presuspend,
+ .postsuspend = snapshot_postsuspend,
+ .preresume = snapshot_preresume,
+ .resume = snapshot_merge_resume,
+ .status = snapshot_status,
+ .iterate_devices = snapshot_iterate_devices,
+};
+
static int __init dm_snapshot_init(void)
{
int r;
@@ -1477,7 +2223,7 @@ static int __init dm_snapshot_init(void)
}
r = dm_register_target(&snapshot_target);
- if (r) {
+ if (r < 0) {
DMERR("snapshot target register failed %d", r);
goto bad_register_snapshot_target;
}
@@ -1485,34 +2231,40 @@ static int __init dm_snapshot_init(void)
r = dm_register_target(&origin_target);
if (r < 0) {
DMERR("Origin target register failed %d", r);
- goto bad1;
+ goto bad_register_origin_target;
+ }
+
+ r = dm_register_target(&merge_target);
+ if (r < 0) {
+ DMERR("Merge target register failed %d", r);
+ goto bad_register_merge_target;
}
r = init_origin_hash();
if (r) {
DMERR("init_origin_hash failed.");
- goto bad2;
+ goto bad_origin_hash;
}
- exception_cache = KMEM_CACHE(dm_snap_exception, 0);
+ exception_cache = KMEM_CACHE(dm_exception, 0);
if (!exception_cache) {
DMERR("Couldn't create exception cache.");
r = -ENOMEM;
- goto bad3;
+ goto bad_exception_cache;
}
pending_cache = KMEM_CACHE(dm_snap_pending_exception, 0);
if (!pending_cache) {
DMERR("Couldn't create pending cache.");
r = -ENOMEM;
- goto bad4;
+ goto bad_pending_cache;
}
tracked_chunk_cache = KMEM_CACHE(dm_snap_tracked_chunk, 0);
if (!tracked_chunk_cache) {
DMERR("Couldn't create cache to track chunks in use.");
r = -ENOMEM;
- goto bad5;
+ goto bad_tracked_chunk_cache;
}
ksnapd = create_singlethread_workqueue("ksnapd");
@@ -1526,19 +2278,21 @@ static int __init dm_snapshot_init(void)
bad_pending_pool:
kmem_cache_destroy(tracked_chunk_cache);
-bad5:
+bad_tracked_chunk_cache:
kmem_cache_destroy(pending_cache);
-bad4:
+bad_pending_cache:
kmem_cache_destroy(exception_cache);
-bad3:
+bad_exception_cache:
exit_origin_hash();
-bad2:
+bad_origin_hash:
+ dm_unregister_target(&merge_target);
+bad_register_merge_target:
dm_unregister_target(&origin_target);
-bad1:
+bad_register_origin_target:
dm_unregister_target(&snapshot_target);
-
bad_register_snapshot_target:
dm_exception_store_exit();
+
return r;
}
@@ -1548,6 +2302,7 @@ static void __exit dm_snapshot_exit(void)
dm_unregister_target(&snapshot_target);
dm_unregister_target(&origin_target);
+ dm_unregister_target(&merge_target);
exit_origin_hash();
kmem_cache_destroy(pending_cache);
diff --git a/drivers/md/dm-sysfs.c b/drivers/md/dm-sysfs.c
index 4b04590..f53392d 100644
--- a/drivers/md/dm-sysfs.c
+++ b/drivers/md/dm-sysfs.c
@@ -59,7 +59,7 @@ static ssize_t dm_attr_uuid_show(struct mapped_device *md, char *buf)
static ssize_t dm_attr_suspended_show(struct mapped_device *md, char *buf)
{
- sprintf(buf, "%d\n", dm_suspended(md));
+ sprintf(buf, "%d\n", dm_suspended_md(md));
return strlen(buf);
}
@@ -80,12 +80,20 @@ static struct sysfs_ops dm_sysfs_ops = {
};
/*
+ * The sysfs structure is embedded in md struct, nothing to do here
+ */
+static void dm_sysfs_release(struct kobject *kobj)
+{
+}
+
+/*
* dm kobject is embedded in mapped_device structure
* no need to define release function here
*/
static struct kobj_type dm_ktype = {
.sysfs_ops = &dm_sysfs_ops,
.default_attrs = dm_attrs,
+ .release = dm_sysfs_release
};
/*
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 91976e8..be62547 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -238,6 +238,9 @@ void dm_table_destroy(struct dm_table *t)
{
unsigned int i;
+ if (!t)
+ return;
+
while (atomic_read(&t->holders))
msleep(1);
smp_mb();
diff --git a/drivers/md/dm-uevent.c b/drivers/md/dm-uevent.c
index 6f65883..c7c555a 100644
--- a/drivers/md/dm-uevent.c
+++ b/drivers/md/dm-uevent.c
@@ -139,14 +139,13 @@ void dm_send_uevents(struct list_head *events, struct kobject *kobj)
list_del_init(&event->elist);
/*
- * Need to call dm_copy_name_and_uuid from here for now.
- * Context of previous var adds and locking used for
- * hash_cell not compatable.
+ * When a device is being removed this copy fails and we
+ * discard these unsent events.
*/
if (dm_copy_name_and_uuid(event->md, event->name,
event->uuid)) {
- DMERR("%s: dm_copy_name_and_uuid() failed",
- __func__);
+ DMINFO("%s: skipping sending uevent for lost device",
+ __func__);
goto uevent_free;
}
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 724efc6..3167480 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -143,9 +143,19 @@ struct mapped_device {
int barrier_error;
/*
+ * Protect barrier_error from concurrent endio processing
+ * in request-based dm.
+ */
+ spinlock_t barrier_error_lock;
+
+ /*
* Processing queue (flush/barriers)
*/
struct workqueue_struct *wq;
+ struct work_struct barrier_work;
+
+ /* A pointer to the currently processing pre/post flush request */
+ struct request *flush_request;
/*
* The current mapping.
@@ -178,9 +188,6 @@ struct mapped_device {
/* forced geometry settings */
struct hd_geometry geometry;
- /* marker of flush suspend for request-based dm */
- struct request suspend_rq;
-
/* For saving the address of __make_request for request based dm */
make_request_fn *saved_make_request_fn;
@@ -275,6 +282,7 @@ static int (*_inits[])(void) __initdata = {
dm_target_init,
dm_linear_init,
dm_stripe_init,
+ dm_io_init,
dm_kcopyd_init,
dm_interface_init,
};
@@ -284,6 +292,7 @@ static void (*_exits[])(void) = {
dm_target_exit,
dm_linear_exit,
dm_stripe_exit,
+ dm_io_exit,
dm_kcopyd_exit,
dm_interface_exit,
};
@@ -320,6 +329,11 @@ static void __exit dm_exit(void)
/*
* Block device functions
*/
+int dm_deleting_md(struct mapped_device *md)
+{
+ return test_bit(DMF_DELETING, &md->flags);
+}
+
static int dm_blk_open(struct block_device *bdev, fmode_t mode)
{
struct mapped_device *md;
@@ -331,7 +345,7 @@ static int dm_blk_open(struct block_device *bdev, fmode_t mode)
goto out;
if (test_bit(DMF_FREEING, &md->flags) ||
- test_bit(DMF_DELETING, &md->flags)) {
+ dm_deleting_md(md)) {
md = NULL;
goto out;
}
@@ -388,7 +402,7 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
struct mapped_device *md = bdev->bd_disk->private_data;
- struct dm_table *map = dm_get_table(md);
+ struct dm_table *map = dm_get_live_table(md);
struct dm_target *tgt;
int r = -ENOTTY;
@@ -401,7 +415,7 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
tgt = dm_table_get_target(map, 0);
- if (dm_suspended(md)) {
+ if (dm_suspended_md(md)) {
r = -EAGAIN;
goto out;
}
@@ -430,9 +444,10 @@ static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
mempool_free(tio, md->tio_pool);
}
-static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md)
+static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
+ gfp_t gfp_mask)
{
- return mempool_alloc(md->tio_pool, GFP_ATOMIC);
+ return mempool_alloc(md->tio_pool, gfp_mask);
}
static void free_rq_tio(struct dm_rq_target_io *tio)
@@ -450,6 +465,12 @@ static void free_bio_info(struct dm_rq_clone_bio_info *info)
mempool_free(info, info->tio->md->io_pool);
}
+static int md_in_flight(struct mapped_device *md)
+{
+ return atomic_read(&md->pending[READ]) +
+ atomic_read(&md->pending[WRITE]);
+}
+
static void start_io_acct(struct dm_io *io)
{
struct mapped_device *md = io->md;
@@ -512,7 +533,7 @@ static void queue_io(struct mapped_device *md, struct bio *bio)
* function to access the md->map field, and make sure they call
* dm_table_put() when finished.
*/
-struct dm_table *dm_get_table(struct mapped_device *md)
+struct dm_table *dm_get_live_table(struct mapped_device *md)
{
struct dm_table *t;
unsigned long flags;
@@ -716,28 +737,38 @@ static void end_clone_bio(struct bio *clone, int error)
blk_update_request(tio->orig, 0, nr_bytes);
}
+static void store_barrier_error(struct mapped_device *md, int error)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&md->barrier_error_lock, flags);
+ /*
+ * Basically, the first error is taken, but:
+ * -EOPNOTSUPP supersedes any I/O error.
+ * Requeue request supersedes any I/O error but -EOPNOTSUPP.
+ */
+ if (!md->barrier_error || error == -EOPNOTSUPP ||
+ (md->barrier_error != -EOPNOTSUPP &&
+ error == DM_ENDIO_REQUEUE))
+ md->barrier_error = error;
+ spin_unlock_irqrestore(&md->barrier_error_lock, flags);
+}
+
/*
* Don't touch any member of the md after calling this function because
* the md may be freed in dm_put() at the end of this function.
* Or do dm_get() before calling this function and dm_put() later.
*/
-static void rq_completed(struct mapped_device *md, int run_queue)
+static void rq_completed(struct mapped_device *md, int rw, int run_queue)
{
- int wakeup_waiters = 0;
- struct request_queue *q = md->queue;
- unsigned long flags;
-
- spin_lock_irqsave(q->queue_lock, flags);
- if (!queue_in_flight(q))
- wakeup_waiters = 1;
- spin_unlock_irqrestore(q->queue_lock, flags);
+ atomic_dec(&md->pending[rw]);
/* nudge anyone waiting on suspend queue */
- if (wakeup_waiters)
+ if (!md_in_flight(md))
wake_up(&md->wait);
if (run_queue)
- blk_run_queue(q);
+ blk_run_queue(md->queue);
/*
* dm_put() must be at the end of this function. See the comment above
@@ -753,6 +784,44 @@ static void free_rq_clone(struct request *clone)
free_rq_tio(tio);
}
+/*
+ * Complete the clone and the original request.
+ * Must be called without queue lock.
+ */
+static void dm_end_request(struct request *clone, int error)
+{
+ int rw = rq_data_dir(clone);
+ int run_queue = 1;
+ bool is_barrier = blk_barrier_rq(clone);
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ struct mapped_device *md = tio->md;
+ struct request *rq = tio->orig;
+
+ if (blk_pc_request(rq) && !is_barrier) {
+ rq->errors = clone->errors;
+ rq->resid_len = clone->resid_len;
+
+ if (rq->sense)
+ /*
+ * We are using the sense buffer of the original
+ * request.
+ * So setting the length of the sense data is enough.
+ */
+ rq->sense_len = clone->sense_len;
+ }
+
+ free_rq_clone(clone);
+
+ if (unlikely(is_barrier)) {
+ if (unlikely(error))
+ store_barrier_error(md, error);
+ run_queue = 0;
+ } else
+ blk_end_request_all(rq, error);
+
+ rq_completed(md, rw, run_queue);
+}
+
static void dm_unprep_request(struct request *rq)
{
struct request *clone = rq->special;
@@ -768,12 +837,23 @@ static void dm_unprep_request(struct request *rq)
*/
void dm_requeue_unmapped_request(struct request *clone)
{
+ int rw = rq_data_dir(clone);
struct dm_rq_target_io *tio = clone->end_io_data;
struct mapped_device *md = tio->md;
struct request *rq = tio->orig;
struct request_queue *q = rq->q;
unsigned long flags;
+ if (unlikely(blk_barrier_rq(clone))) {
+ /*
+ * Barrier clones share an original request.
+ * Leave it to dm_end_request(), which handles this special
+ * case.
+ */
+ dm_end_request(clone, DM_ENDIO_REQUEUE);
+ return;
+ }
+
dm_unprep_request(rq);
spin_lock_irqsave(q->queue_lock, flags);
@@ -782,7 +862,7 @@ void dm_requeue_unmapped_request(struct request *clone)
blk_requeue_request(q, rq);
spin_unlock_irqrestore(q->queue_lock, flags);
- rq_completed(md, 0);
+ rq_completed(md, rw, 0);
}
EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request);
@@ -815,34 +895,28 @@ static void start_queue(struct request_queue *q)
spin_unlock_irqrestore(q->queue_lock, flags);
}
-/*
- * Complete the clone and the original request.
- * Must be called without queue lock.
- */
-static void dm_end_request(struct request *clone, int error)
+static void dm_done(struct request *clone, int error, bool mapped)
{
+ int r = error;
struct dm_rq_target_io *tio = clone->end_io_data;
- struct mapped_device *md = tio->md;
- struct request *rq = tio->orig;
+ dm_request_endio_fn rq_end_io = tio->ti->type->rq_end_io;
- if (blk_pc_request(rq)) {
- rq->errors = clone->errors;
- rq->resid_len = clone->resid_len;
+ if (mapped && rq_end_io)
+ r = rq_end_io(tio->ti, clone, error, &tio->info);
- if (rq->sense)
- /*
- * We are using the sense buffer of the original
- * request.
- * So setting the length of the sense data is enough.
- */
- rq->sense_len = clone->sense_len;
+ if (r <= 0)
+ /* The target wants to complete the I/O */
+ dm_end_request(clone, r);
+ else if (r == DM_ENDIO_INCOMPLETE)
+ /* The target will handle the I/O */
+ return;
+ else if (r == DM_ENDIO_REQUEUE)
+ /* The target wants to requeue the I/O */
+ dm_requeue_unmapped_request(clone);
+ else {
+ DMWARN("unimplemented target endio return value: %d", r);
+ BUG();
}
-
- free_rq_clone(clone);
-
- blk_end_request_all(rq, error);
-
- rq_completed(md, 1);
}
/*
@@ -850,27 +924,14 @@ static void dm_end_request(struct request *clone, int error)
*/
static void dm_softirq_done(struct request *rq)
{
+ bool mapped = true;
struct request *clone = rq->completion_data;
struct dm_rq_target_io *tio = clone->end_io_data;
- dm_request_endio_fn rq_end_io = tio->ti->type->rq_end_io;
- int error = tio->error;
- if (!(rq->cmd_flags & REQ_FAILED) && rq_end_io)
- error = rq_end_io(tio->ti, clone, error, &tio->info);
+ if (rq->cmd_flags & REQ_FAILED)
+ mapped = false;
- if (error <= 0)
- /* The target wants to complete the I/O */
- dm_end_request(clone, error);
- else if (error == DM_ENDIO_INCOMPLETE)
- /* The target will handle the I/O */
- return;
- else if (error == DM_ENDIO_REQUEUE)
- /* The target wants to requeue the I/O */
- dm_requeue_unmapped_request(clone);
- else {
- DMWARN("unimplemented target endio return value: %d", error);
- BUG();
- }
+ dm_done(clone, tio->error, mapped);
}
/*
@@ -882,6 +943,19 @@ static void dm_complete_request(struct request *clone, int error)
struct dm_rq_target_io *tio = clone->end_io_data;
struct request *rq = tio->orig;
+ if (unlikely(blk_barrier_rq(clone))) {
+ /*
+ * Barrier clones share an original request. So can't use
+ * softirq_done with the original.
+ * Pass the clone to dm_done() directly in this special case.
+ * It is safe (even if clone->q->queue_lock is held here)
+ * because there is no I/O dispatching during the completion
+ * of barrier clone.
+ */
+ dm_done(clone, error, true);
+ return;
+ }
+
tio->error = error;
rq->completion_data = clone;
blk_complete_request(rq);
@@ -898,6 +972,17 @@ void dm_kill_unmapped_request(struct request *clone, int error)
struct dm_rq_target_io *tio = clone->end_io_data;
struct request *rq = tio->orig;
+ if (unlikely(blk_barrier_rq(clone))) {
+ /*
+ * Barrier clones share an original request.
+ * Leave it to dm_end_request(), which handles this special
+ * case.
+ */
+ BUG_ON(error > 0);
+ dm_end_request(clone, error);
+ return;
+ }
+
rq->cmd_flags |= REQ_FAILED;
dm_complete_request(clone, error);
}
@@ -1214,7 +1299,7 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
struct clone_info ci;
int error = 0;
- ci.map = dm_get_table(md);
+ ci.map = dm_get_live_table(md);
if (unlikely(!ci.map)) {
if (!bio_rw_flagged(bio, BIO_RW_BARRIER))
bio_io_error(bio);
@@ -1255,7 +1340,7 @@ static int dm_merge_bvec(struct request_queue *q,
struct bio_vec *biovec)
{
struct mapped_device *md = q->queuedata;
- struct dm_table *map = dm_get_table(md);
+ struct dm_table *map = dm_get_live_table(md);
struct dm_target *ti;
sector_t max_sectors;
int max_size = 0;
@@ -1352,11 +1437,6 @@ static int dm_make_request(struct request_queue *q, struct bio *bio)
{
struct mapped_device *md = q->queuedata;
- if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
- bio_endio(bio, -EOPNOTSUPP);
- return 0;
- }
-
return md->saved_make_request_fn(q, bio); /* call __make_request() */
}
@@ -1375,6 +1455,25 @@ static int dm_request(struct request_queue *q, struct bio *bio)
return _dm_request(q, bio);
}
+/*
+ * Mark this request as flush request, so that dm_request_fn() can
+ * recognize.
+ */
+static void dm_rq_prepare_flush(struct request_queue *q, struct request *rq)
+{
+ rq->cmd_type = REQ_TYPE_LINUX_BLOCK;
+ rq->cmd[0] = REQ_LB_OP_FLUSH;
+}
+
+static bool dm_rq_is_flush_request(struct request *rq)
+{
+ if (rq->cmd_type == REQ_TYPE_LINUX_BLOCK &&
+ rq->cmd[0] == REQ_LB_OP_FLUSH)
+ return true;
+ else
+ return false;
+}
+
void dm_dispatch_request(struct request *rq)
{
int r;
@@ -1420,25 +1519,54 @@ static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
static int setup_clone(struct request *clone, struct request *rq,
struct dm_rq_target_io *tio)
{
- int r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC,
- dm_rq_bio_constructor, tio);
+ int r;
- if (r)
- return r;
+ if (dm_rq_is_flush_request(rq)) {
+ blk_rq_init(NULL, clone);
+ clone->cmd_type = REQ_TYPE_FS;
+ clone->cmd_flags |= (REQ_HARDBARRIER | WRITE);
+ } else {
+ r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC,
+ dm_rq_bio_constructor, tio);
+ if (r)
+ return r;
+
+ clone->cmd = rq->cmd;
+ clone->cmd_len = rq->cmd_len;
+ clone->sense = rq->sense;
+ clone->buffer = rq->buffer;
+ }
- clone->cmd = rq->cmd;
- clone->cmd_len = rq->cmd_len;
- clone->sense = rq->sense;
- clone->buffer = rq->buffer;
clone->end_io = end_clone_request;
clone->end_io_data = tio;
return 0;
}
-static int dm_rq_flush_suspending(struct mapped_device *md)
+static struct request *clone_rq(struct request *rq, struct mapped_device *md,
+ gfp_t gfp_mask)
{
- return !md->suspend_rq.special;
+ struct request *clone;
+ struct dm_rq_target_io *tio;
+
+ tio = alloc_rq_tio(md, gfp_mask);
+ if (!tio)
+ return NULL;
+
+ tio->md = md;
+ tio->ti = NULL;
+ tio->orig = rq;
+ tio->error = 0;
+ memset(&tio->info, 0, sizeof(tio->info));
+
+ clone = &tio->clone;
+ if (setup_clone(clone, rq, tio)) {
+ /* -ENOMEM */
+ free_rq_tio(tio);
+ return NULL;
+ }
+
+ return clone;
}
/*
@@ -1447,39 +1575,19 @@ static int dm_rq_flush_suspending(struct mapped_device *md)
static int dm_prep_fn(struct request_queue *q, struct request *rq)
{
struct mapped_device *md = q->queuedata;
- struct dm_rq_target_io *tio;
struct request *clone;
- if (unlikely(rq == &md->suspend_rq)) {
- if (dm_rq_flush_suspending(md))
- return BLKPREP_OK;
- else
- /* The flush suspend was interrupted */
- return BLKPREP_KILL;
- }
+ if (unlikely(dm_rq_is_flush_request(rq)))
+ return BLKPREP_OK;
if (unlikely(rq->special)) {
DMWARN("Already has something in rq->special.");
return BLKPREP_KILL;
}
- tio = alloc_rq_tio(md); /* Only one for each original request */
- if (!tio)
- /* -ENOMEM */
- return BLKPREP_DEFER;
-
- tio->md = md;
- tio->ti = NULL;
- tio->orig = rq;
- tio->error = 0;
- memset(&tio->info, 0, sizeof(tio->info));
-
- clone = &tio->clone;
- if (setup_clone(clone, rq, tio)) {
- /* -ENOMEM */
- free_rq_tio(tio);
+ clone = clone_rq(rq, md, GFP_ATOMIC);
+ if (!clone)
return BLKPREP_DEFER;
- }
rq->special = clone;
rq->cmd_flags |= REQ_DONTPREP;
@@ -1487,11 +1595,10 @@ static int dm_prep_fn(struct request_queue *q, struct request *rq)
return BLKPREP_OK;
}
-static void map_request(struct dm_target *ti, struct request *rq,
+static void map_request(struct dm_target *ti, struct request *clone,
struct mapped_device *md)
{
int r;
- struct request *clone = rq->special;
struct dm_rq_target_io *tio = clone->end_io_data;
/*
@@ -1511,6 +1618,8 @@ static void map_request(struct dm_target *ti, struct request *rq,
break;
case DM_MAPIO_REMAPPED:
/* The target has remapped the I/O so dispatch it */
+ trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
+ blk_rq_pos(tio->orig));
dm_dispatch_request(clone);
break;
case DM_MAPIO_REQUEUE:
@@ -1536,29 +1645,26 @@ static void map_request(struct dm_target *ti, struct request *rq,
static void dm_request_fn(struct request_queue *q)
{
struct mapped_device *md = q->queuedata;
- struct dm_table *map = dm_get_table(md);
+ struct dm_table *map = dm_get_live_table(md);
struct dm_target *ti;
- struct request *rq;
+ struct request *rq, *clone;
/*
- * For noflush suspend, check blk_queue_stopped() to immediately
- * quit I/O dispatching.
+ * For suspend, check blk_queue_stopped() and increment
+ * ->pending within a single queue_lock not to increment the
+ * number of in-flight I/Os after the queue is stopped in
+ * dm_suspend().
*/
while (!blk_queue_plugged(q) && !blk_queue_stopped(q)) {
rq = blk_peek_request(q);
if (!rq)
goto plug_and_out;
- if (unlikely(rq == &md->suspend_rq)) { /* Flush suspend maker */
- if (queue_in_flight(q))
- /* Not quiet yet. Wait more */
- goto plug_and_out;
-
- /* This device should be quiet now */
- __stop_queue(q);
+ if (unlikely(dm_rq_is_flush_request(rq))) {
+ BUG_ON(md->flush_request);
+ md->flush_request = rq;
blk_start_request(rq);
- __blk_end_request_all(rq, 0);
- wake_up(&md->wait);
+ queue_work(md->wq, &md->barrier_work);
goto out;
}
@@ -1567,8 +1673,11 @@ static void dm_request_fn(struct request_queue *q)
goto plug_and_out;
blk_start_request(rq);
+ clone = rq->special;
+ atomic_inc(&md->pending[rq_data_dir(clone)]);
+
spin_unlock(q->queue_lock);
- map_request(ti, rq, md);
+ map_request(ti, clone, md);
spin_lock_irq(q->queue_lock);
}
@@ -1595,7 +1704,7 @@ static int dm_lld_busy(struct request_queue *q)
{
int r;
struct mapped_device *md = q->queuedata;
- struct dm_table *map = dm_get_table(md);
+ struct dm_table *map = dm_get_live_table(md);
if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))
r = 1;
@@ -1610,7 +1719,7 @@ static int dm_lld_busy(struct request_queue *q)
static void dm_unplug_all(struct request_queue *q)
{
struct mapped_device *md = q->queuedata;
- struct dm_table *map = dm_get_table(md);
+ struct dm_table *map = dm_get_live_table(md);
if (map) {
if (dm_request_based(md))
@@ -1628,7 +1737,7 @@ static int dm_any_congested(void *congested_data, int bdi_bits)
struct dm_table *map;
if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
- map = dm_get_table(md);
+ map = dm_get_live_table(md);
if (map) {
/*
* Request-based dm cares about only own queue for
@@ -1725,6 +1834,7 @@ out:
static const struct block_device_operations dm_blk_dops;
static void dm_wq_work(struct work_struct *work);
+static void dm_rq_barrier_work(struct work_struct *work);
/*
* Allocate and initialise a blank device with a given minor.
@@ -1754,6 +1864,7 @@ static struct mapped_device *alloc_dev(int minor)
init_rwsem(&md->io_lock);
mutex_init(&md->suspend_lock);
spin_lock_init(&md->deferred_lock);
+ spin_lock_init(&md->barrier_error_lock);
rwlock_init(&md->map_lock);
atomic_set(&md->holders, 1);
atomic_set(&md->open_count, 0);
@@ -1788,6 +1899,8 @@ static struct mapped_device *alloc_dev(int minor)
blk_queue_softirq_done(md->queue, dm_softirq_done);
blk_queue_prep_rq(md->queue, dm_prep_fn);
blk_queue_lld_busy(md->queue, dm_lld_busy);
+ blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN_FLUSH,
+ dm_rq_prepare_flush);
md->disk = alloc_disk(1);
if (!md->disk)
@@ -1797,6 +1910,7 @@ static struct mapped_device *alloc_dev(int minor)
atomic_set(&md->pending[1], 0);
init_waitqueue_head(&md->wait);
INIT_WORK(&md->work, dm_wq_work);
+ INIT_WORK(&md->barrier_work, dm_rq_barrier_work);
init_waitqueue_head(&md->eventq);
md->disk->major = _major;
@@ -1921,9 +2035,13 @@ static void __set_size(struct mapped_device *md, sector_t size)
mutex_unlock(&md->bdev->bd_inode->i_mutex);
}
-static int __bind(struct mapped_device *md, struct dm_table *t,
- struct queue_limits *limits)
+/*
+ * Returns old map, which caller must destroy.
+ */
+static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
+ struct queue_limits *limits)
{
+ struct dm_table *old_map;
struct request_queue *q = md->queue;
sector_t size;
unsigned long flags;
@@ -1938,11 +2056,6 @@ static int __bind(struct mapped_device *md, struct dm_table *t,
__set_size(md, size);
- if (!size) {
- dm_table_destroy(t);
- return 0;
- }
-
dm_table_event_callback(t, event_callback, md);
/*
@@ -1958,26 +2071,31 @@ static int __bind(struct mapped_device *md, struct dm_table *t,
__bind_mempools(md, t);
write_lock_irqsave(&md->map_lock, flags);
+ old_map = md->map;
md->map = t;
dm_table_set_restrictions(t, q, limits);
write_unlock_irqrestore(&md->map_lock, flags);
- return 0;
+ return old_map;
}
-static void __unbind(struct mapped_device *md)
+/*
+ * Returns unbound table for the caller to free.
+ */
+static struct dm_table *__unbind(struct mapped_device *md)
{
struct dm_table *map = md->map;
unsigned long flags;
if (!map)
- return;
+ return NULL;
dm_table_event_callback(map, NULL, NULL);
write_lock_irqsave(&md->map_lock, flags);
md->map = NULL;
write_unlock_irqrestore(&md->map_lock, flags);
- dm_table_destroy(map);
+
+ return map;
}
/*
@@ -2059,18 +2177,18 @@ void dm_put(struct mapped_device *md)
BUG_ON(test_bit(DMF_FREEING, &md->flags));
if (atomic_dec_and_lock(&md->holders, &_minor_lock)) {
- map = dm_get_table(md);
+ map = dm_get_live_table(md);
idr_replace(&_minor_idr, MINOR_ALLOCED,
MINOR(disk_devt(dm_disk(md))));
set_bit(DMF_FREEING, &md->flags);
spin_unlock(&_minor_lock);
- if (!dm_suspended(md)) {
+ if (!dm_suspended_md(md)) {
dm_table_presuspend_targets(map);
dm_table_postsuspend_targets(map);
}
dm_sysfs_exit(md);
dm_table_put(map);
- __unbind(md);
+ dm_table_destroy(__unbind(md));
free_dev(md);
}
}
@@ -2080,8 +2198,6 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
{
int r = 0;
DECLARE_WAITQUEUE(wait, current);
- struct request_queue *q = md->queue;
- unsigned long flags;
dm_unplug_all(md->queue);
@@ -2091,15 +2207,7 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
set_current_state(interruptible);
smp_mb();
- if (dm_request_based(md)) {
- spin_lock_irqsave(q->queue_lock, flags);
- if (!queue_in_flight(q) && blk_queue_stopped(q)) {
- spin_unlock_irqrestore(q->queue_lock, flags);
- break;
- }
- spin_unlock_irqrestore(q->queue_lock, flags);
- } else if (!atomic_read(&md->pending[0]) &&
- !atomic_read(&md->pending[1]))
+ if (!md_in_flight(md))
break;
if (interruptible == TASK_INTERRUPTIBLE &&
@@ -2194,98 +2302,106 @@ static void dm_queue_flush(struct mapped_device *md)
queue_work(md->wq, &md->work);
}
-/*
- * Swap in a new table (destroying old one).
- */
-int dm_swap_table(struct mapped_device *md, struct dm_table *table)
+static void dm_rq_set_flush_nr(struct request *clone, unsigned flush_nr)
{
- struct queue_limits limits;
- int r = -EINVAL;
+ struct dm_rq_target_io *tio = clone->end_io_data;
- mutex_lock(&md->suspend_lock);
+ tio->info.flush_request = flush_nr;
+}
- /* device must be suspended */
- if (!dm_suspended(md))
- goto out;
+/* Issue barrier requests to targets and wait for their completion. */
+static int dm_rq_barrier(struct mapped_device *md)
+{
+ int i, j;
+ struct dm_table *map = dm_get_live_table(md);
+ unsigned num_targets = dm_table_get_num_targets(map);
+ struct dm_target *ti;
+ struct request *clone;
- r = dm_calculate_queue_limits(table, &limits);
- if (r)
- goto out;
+ md->barrier_error = 0;
- /* cannot change the device type, once a table is bound */
- if (md->map &&
- (dm_table_get_type(md->map) != dm_table_get_type(table))) {
- DMWARN("can't change the device type after a table is bound");
- goto out;
+ for (i = 0; i < num_targets; i++) {
+ ti = dm_table_get_target(map, i);
+ for (j = 0; j < ti->num_flush_requests; j++) {
+ clone = clone_rq(md->flush_request, md, GFP_NOIO);
+ dm_rq_set_flush_nr(clone, j);
+ atomic_inc(&md->pending[rq_data_dir(clone)]);
+ map_request(ti, clone, md);
+ }
}
- __unbind(md);
- r = __bind(md, table, &limits);
-
-out:
- mutex_unlock(&md->suspend_lock);
- return r;
-}
+ dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
+ dm_table_put(map);
-static void dm_rq_invalidate_suspend_marker(struct mapped_device *md)
-{
- md->suspend_rq.special = (void *)0x1;
+ return md->barrier_error;
}
-static void dm_rq_abort_suspend(struct mapped_device *md, int noflush)
+static void dm_rq_barrier_work(struct work_struct *work)
{
+ int error;
+ struct mapped_device *md = container_of(work, struct mapped_device,
+ barrier_work);
struct request_queue *q = md->queue;
+ struct request *rq;
unsigned long flags;
- spin_lock_irqsave(q->queue_lock, flags);
- if (!noflush)
- dm_rq_invalidate_suspend_marker(md);
- __start_queue(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
-}
+ /*
+ * Hold the md reference here and leave it at the last part so that
+ * the md can't be deleted by device opener when the barrier request
+ * completes.
+ */
+ dm_get(md);
-static void dm_rq_start_suspend(struct mapped_device *md, int noflush)
-{
- struct request *rq = &md->suspend_rq;
- struct request_queue *q = md->queue;
+ error = dm_rq_barrier(md);
- if (noflush)
- stop_queue(q);
- else {
- blk_rq_init(q, rq);
- blk_insert_request(q, rq, 0, NULL);
- }
+ rq = md->flush_request;
+ md->flush_request = NULL;
+
+ if (error == DM_ENDIO_REQUEUE) {
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_requeue_request(q, rq);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ } else
+ blk_end_request_all(rq, error);
+
+ blk_run_queue(q);
+
+ dm_put(md);
}
-static int dm_rq_suspend_available(struct mapped_device *md, int noflush)
+/*
+ * Swap in a new table, returning the old one for the caller to destroy.
+ */
+struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
{
- int r = 1;
- struct request *rq = &md->suspend_rq;
- struct request_queue *q = md->queue;
- unsigned long flags;
+ struct dm_table *map = ERR_PTR(-EINVAL);
+ struct queue_limits limits;
+ int r;
- if (noflush)
- return r;
+ mutex_lock(&md->suspend_lock);
- /* The marker must be protected by queue lock if it is in use */
- spin_lock_irqsave(q->queue_lock, flags);
- if (unlikely(rq->ref_count)) {
- /*
- * This can happen, when the previous flush suspend was
- * interrupted, the marker is still in the queue and
- * this flush suspend has been invoked, because we don't
- * remove the marker at the time of suspend interruption.
- * We have only one marker per mapped_device, so we can't
- * start another flush suspend while it is in use.
- */
- BUG_ON(!rq->special); /* The marker should be invalidated */
- DMWARN("Invalidating the previous flush suspend is still in"
- " progress. Please retry later.");
- r = 0;
+ /* device must be suspended */
+ if (!dm_suspended_md(md))
+ goto out;
+
+ r = dm_calculate_queue_limits(table, &limits);
+ if (r) {
+ map = ERR_PTR(r);
+ goto out;
}
- spin_unlock_irqrestore(q->queue_lock, flags);
- return r;
+ /* cannot change the device type, once a table is bound */
+ if (md->map &&
+ (dm_table_get_type(md->map) != dm_table_get_type(table))) {
+ DMWARN("can't change the device type after a table is bound");
+ goto out;
+ }
+
+ map = __bind(md, table, &limits);
+
+out:
+ mutex_unlock(&md->suspend_lock);
+ return map;
}
/*
@@ -2330,49 +2446,11 @@ static void unlock_fs(struct mapped_device *md)
/*
* Suspend mechanism in request-based dm.
*
- * After the suspend starts, further incoming requests are kept in
- * the request_queue and deferred.
- * Remaining requests in the request_queue at the start of suspend are flushed
- * if it is flush suspend.
- * The suspend completes when the following conditions have been satisfied,
- * so wait for it:
- * 1. q->in_flight is 0 (which means no in_flight request)
- * 2. queue has been stopped (which means no request dispatching)
- *
+ * 1. Flush all I/Os by lock_fs() if needed.
+ * 2. Stop dispatching any I/O by stopping the request_queue.
+ * 3. Wait for all in-flight I/Os to be completed or requeued.
*
- * Noflush suspend
- * ---------------
- * Noflush suspend doesn't need to dispatch remaining requests.
- * So stop the queue immediately. Then, wait for all in_flight requests
- * to be completed or requeued.
- *
- * To abort noflush suspend, start the queue.
- *
- *
- * Flush suspend
- * -------------
- * Flush suspend needs to dispatch remaining requests. So stop the queue
- * after the remaining requests are completed. (Requeued request must be also
- * re-dispatched and completed. Until then, we can't stop the queue.)
- *
- * During flushing the remaining requests, further incoming requests are also
- * inserted to the same queue. To distinguish which requests are to be
- * flushed, we insert a marker request to the queue at the time of starting
- * flush suspend, like a barrier.
- * The dispatching is blocked when the marker is found on the top of the queue.
- * And the queue is stopped when all in_flight requests are completed, since
- * that means the remaining requests are completely flushed.
- * Then, the marker is removed from the queue.
- *
- * To abort flush suspend, we also need to take care of the marker, not only
- * starting the queue.
- * We don't remove the marker forcibly from the queue since it's against
- * the block-layer manner. Instead, we put a invalidated mark on the marker.
- * When the invalidated marker is found on the top of the queue, it is
- * immediately removed from the queue, so it doesn't block dispatching.
- * Because we have only one marker per mapped_device, we can't start another
- * flush suspend until the invalidated marker is removed from the queue.
- * So fail and return with -EBUSY in such a case.
+ * To abort suspend, start the request_queue.
*/
int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
{
@@ -2383,17 +2461,12 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
mutex_lock(&md->suspend_lock);
- if (dm_suspended(md)) {
+ if (dm_suspended_md(md)) {
r = -EINVAL;
goto out_unlock;
}
- if (dm_request_based(md) && !dm_rq_suspend_available(md, noflush)) {
- r = -EBUSY;
- goto out_unlock;
- }
-
- map = dm_get_table(md);
+ map = dm_get_live_table(md);
/*
* DMF_NOFLUSH_SUSPENDING must be set before presuspend.
@@ -2406,8 +2479,10 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
dm_table_presuspend_targets(map);
/*
- * Flush I/O to the device. noflush supersedes do_lockfs,
- * because lock_fs() needs to flush I/Os.
+ * Flush I/O to the device.
+ * Any I/O submitted after lock_fs() may not be flushed.
+ * noflush takes precedence over do_lockfs.
+ * (lock_fs() flushes I/Os and waits for them to complete.)
*/
if (!noflush && do_lockfs) {
r = lock_fs(md);
@@ -2436,10 +2511,15 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
up_write(&md->io_lock);
- flush_workqueue(md->wq);
-
+ /*
+ * Request-based dm uses md->wq for barrier (dm_rq_barrier_work) which
+ * can be kicked until md->queue is stopped. So stop md->queue before
+ * flushing md->wq.
+ */
if (dm_request_based(md))
- dm_rq_start_suspend(md, noflush);
+ stop_queue(md->queue);
+
+ flush_workqueue(md->wq);
/*
* At this point no more requests are entering target request routines.
@@ -2458,7 +2538,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
dm_queue_flush(md);
if (dm_request_based(md))
- dm_rq_abort_suspend(md, noflush);
+ start_queue(md->queue);
unlock_fs(md);
goto out; /* pushback list is already flushed, so skip flush */
@@ -2470,10 +2550,10 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
* requests are being added to md->deferred list.
*/
- dm_table_postsuspend_targets(map);
-
set_bit(DMF_SUSPENDED, &md->flags);
+ dm_table_postsuspend_targets(map);
+
out:
dm_table_put(map);
@@ -2488,10 +2568,10 @@ int dm_resume(struct mapped_device *md)
struct dm_table *map = NULL;
mutex_lock(&md->suspend_lock);
- if (!dm_suspended(md))
+ if (!dm_suspended_md(md))
goto out;
- map = dm_get_table(md);
+ map = dm_get_live_table(md);
if (!map || !dm_table_get_size(map))
goto out;
@@ -2592,18 +2672,29 @@ struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
return NULL;
if (test_bit(DMF_FREEING, &md->flags) ||
- test_bit(DMF_DELETING, &md->flags))
+ dm_deleting_md(md))
return NULL;
dm_get(md);
return md;
}
-int dm_suspended(struct mapped_device *md)
+int dm_suspended_md(struct mapped_device *md)
{
return test_bit(DMF_SUSPENDED, &md->flags);
}
+int dm_suspended(struct dm_target *ti)
+{
+ struct mapped_device *md = dm_table_get_md(ti->table);
+ int r = dm_suspended_md(md);
+
+ dm_put(md);
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_suspended);
+
int dm_noflush_suspending(struct dm_target *ti)
{
struct mapped_device *md = dm_table_get_md(ti->table);
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index a7663eb..8dadaa5 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -89,6 +89,16 @@ int dm_target_iterate(void (*iter_func)(struct target_type *tt,
int dm_split_args(int *argc, char ***argvp, char *input);
/*
+ * Is this mapped_device being deleted?
+ */
+int dm_deleting_md(struct mapped_device *md);
+
+/*
+ * Is this mapped_device suspended?
+ */
+int dm_suspended_md(struct mapped_device *md);
+
+/*
* The device-mapper can be driven through one of two interfaces;
* ioctl or filesystem, depending which patch you have applied.
*/
@@ -118,6 +128,9 @@ int dm_lock_for_deletion(struct mapped_device *md);
void dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
unsigned cookie);
+int dm_io_init(void);
+void dm_io_exit(void);
+
int dm_kcopyd_init(void);
void dm_kcopyd_exit(void);
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index df7607e..d4c9c0b 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -235,7 +235,7 @@ void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
const char *dm_device_name(struct mapped_device *md);
int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
struct gendisk *dm_disk(struct mapped_device *md);
-int dm_suspended(struct mapped_device *md);
+int dm_suspended(struct dm_target *ti);
int dm_noflush_suspending(struct dm_target *ti);
union map_info *dm_get_mapinfo(struct bio *bio);
union map_info *dm_get_rq_mapinfo(struct request *rq);
@@ -276,7 +276,7 @@ void dm_table_unplug_all(struct dm_table *t);
/*
* Table reference counting.
*/
-struct dm_table *dm_get_table(struct mapped_device *md);
+struct dm_table *dm_get_live_table(struct mapped_device *md);
void dm_table_get(struct dm_table *t);
void dm_table_put(struct dm_table *t);
@@ -295,8 +295,10 @@ void dm_table_event(struct dm_table *t);
/*
* The device must be suspended before calling this method.
+ * Returns the previous table, which the caller must destroy.
*/
-int dm_swap_table(struct mapped_device *md, struct dm_table *t);
+struct dm_table *dm_swap_table(struct mapped_device *md,
+ struct dm_table *t);
/*
* A wrapper around vmalloc.
diff --git a/include/linux/dm-dirty-log.h b/include/linux/dm-dirty-log.h
index 5e8b11d..7084503 100644
--- a/include/linux/dm-dirty-log.h
+++ b/include/linux/dm-dirty-log.h
@@ -21,6 +21,7 @@ struct dm_dirty_log_type;
struct dm_dirty_log {
struct dm_dirty_log_type *type;
+ int (*flush_callback_fn)(struct dm_target *ti);
void *context;
};
@@ -136,8 +137,9 @@ int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type);
* type->constructor/destructor() directly.
*/
struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
- struct dm_target *ti,
- unsigned argc, char **argv);
+ struct dm_target *ti,
+ int (*flush_callback_fn)(struct dm_target *ti),
+ unsigned argc, char **argv);
void dm_dirty_log_destroy(struct dm_dirty_log *log);
#endif /* __KERNEL__ */
diff --git a/include/linux/dm-ioctl.h b/include/linux/dm-ioctl.h
index 2ab84c8..aa95508 100644
--- a/include/linux/dm-ioctl.h
+++ b/include/linux/dm-ioctl.h
@@ -1,6 +1,6 @@
/*
* Copyright (C) 2001 - 2003 Sistina Software (UK) Limited.
- * Copyright (C) 2004 - 2005 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004 - 2009 Red Hat, Inc. All rights reserved.
*
* This file is released under the LGPL.
*/
@@ -266,9 +266,9 @@ 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 15
+#define DM_VERSION_MINOR 16
#define DM_VERSION_PATCHLEVEL 0
-#define DM_VERSION_EXTRA "-ioctl (2009-04-01)"
+#define DM_VERSION_EXTRA "-ioctl (2009-11-05)"
/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */
@@ -309,4 +309,11 @@ enum {
*/
#define DM_NOFLUSH_FLAG (1 << 11) /* In */
+/*
+ * If set, any table information returned will relate to the inactive
+ * table instead of the live one. Always check DM_INACTIVE_PRESENT_FLAG
+ * is set before using the data returned.
+ */
+#define DM_QUERY_INACTIVE_TABLE_FLAG (1 << 12) /* In */
+
#endif /* _LINUX_DM_IOCTL_H */
diff --git a/include/linux/dm-region-hash.h b/include/linux/dm-region-hash.h
index a9e652a..9e2a7a4 100644
--- a/include/linux/dm-region-hash.h
+++ b/include/linux/dm-region-hash.h
@@ -78,8 +78,7 @@ void dm_rh_dec(struct dm_region_hash *rh, region_t region);
/* Delay bios on regions. */
void dm_rh_delay(struct dm_region_hash *rh, struct bio *bio);
-void dm_rh_mark_nosync(struct dm_region_hash *rh,
- struct bio *bio, unsigned done, int error);
+void dm_rh_mark_nosync(struct dm_region_hash *rh, struct bio *bio);
/*
* Region recovery control.
generated by cgit v0.10.2 at 2024-11-09 21:18:58 (GMT)