summaryrefslogtreecommitdiff
path: root/drivers/md/dm-table.c
AgeCommit message (Collapse)Author
2015-06-26Revert "block, dm: don't copy bios for request clones"Mike Snitzer
This reverts commit 5f1b670d0bef508a5554d92525f5f6d00d640b38. Justification for revert as reported in this dm-devel post: https://www.redhat.com/archives/dm-devel/2015-June/msg00160.html this change should not be pushed to mainline yet. Firstly, Christoph has a newer version of the patch that fixes silent data corruption problem: https://www.redhat.com/archives/dm-devel/2015-May/msg00229.html And the new version still depends on LLDDs to always complete requests to the end when error happens, while block API doesn't enforce such a requirement. If the assumption is ever broken, the inconsistency between request and bio (e.g. rq->__sector and rq->bio) will cause silent data corruption: https://www.redhat.com/archives/dm-devel/2015-June/msg00022.html Reported-by: Junichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-06-26Revert "dm: do not allocate any mempools for blk-mq request-based DM"Mike Snitzer
This reverts commit cbc4e3c1350beb47beab8f34ad9be3d34a20c705. Reported-by: Junichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29dm: do not allocate any mempools for blk-mq request-based DMMike Snitzer
Do not allocate the io_pool mempool for blk-mq request-based DM (DM_TYPE_MQ_REQUEST_BASED) in dm_alloc_rq_mempools(). Also refine __bind_mempools() to have more precise awareness of which mempools each type of DM device uses -- avoids mempool churn when reloading DM tables (particularly for DM_TYPE_REQUEST_BASED). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29Merge remote-tracking branch 'jens/for-4.2/core' into dm-4.2Mike Snitzer
2015-05-29dm: fix reload failure of 0 path multipath mapping on blk-mq devicesJunichi Nomura
dm-multipath accepts 0 path mapping. # echo '0 2097152 multipath 0 0 0 0' | dmsetup create newdev Such a mapping can be used to release underlying devices while still holding requests in its queue until working paths come back. However, once the multipath device is created over blk-mq devices, it rejects reloading of 0 path mapping: # echo '0 2097152 multipath 0 0 1 1 queue-length 0 1 1 /dev/sda 1' \ | dmsetup create mpath1 # echo '0 2097152 multipath 0 0 0 0' | dmsetup load mpath1 device-mapper: reload ioctl on mpath1 failed: Invalid argument Command failed With following kernel message: device-mapper: ioctl: can't change device type after initial table load. DM tries to inherit the current table type using dm_table_set_type() but it doesn't work as expected because of unnecessary check about whether the target type is hybrid or not. Hybrid type is for targets that work as either request-based or bio-based and not required for blk-mq or non blk-mq checking. Fixes: 65803c205983 ("dm table: train hybrid target type detection to select blk-mq if appropriate") Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-22block, dm: don't copy bios for request clonesChristoph Hellwig
Currently dm-multipath has to clone the bios for every request sent to the lower devices, which wastes cpu cycles and ties down memory. This patch instead adds a new REQ_CLONE flag that instructs req_bio_endio to not complete bios attached to a request, which we set on clone requests similar to bios in a flush sequence. With this change I/O errors on a path failure only get propagated to dm-multipath, which can then either resubmit the I/O or complete the bios on the original request. I've done some basic testing of this on a Linux target with ALUA support, and it survives path failures during I/O nicely. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-04-15dm table: use bool function return values of true/false not 1/0Joe Perches
Use the normal return values for bool functions. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15dm table: fall back to getting device using name_to_dev_t()Dan Ehrenberg
If a device is used as the root filesystem, it can't be built off of devices which are within the root filesystem (just like command line arguments to root=). For this reason, Linux has a pseudo-filesystem for root= and MD initialization (based on the function name_to_dev_t) which handles different ways of specifying devices including PARTUUID and major:minor. Switch to using name_to_dev_t() in dm_get_device(). Rather than having DM assume that all things which are not major:minor are paths in an already-mounted filesystem, change dm_get_device() to first attempt to look up the device in the filesystem, and if not found it will fall back to using name_to_dev_t(). In terms of backwards compatibility, there are some cases where behavior will be different: - If you have a file in the current working directory named 1:2 and you initialze DM there, then it will try to use that file rather than the disk with that major:minor pair as a backing device. - Similarly for other bdev types which name_to_dev_t() knows how to interpret, the previous behavior was to repeatedly check for the existence of the file (e.g., while waiting for rootfs to come up) but the new behavior is to use the name_to_dev_t() interpretation. For example, if you have a file named /dev/ubiblock0_0 which is a symlink to /dev/sda3, but it is not yet present when DM starts to initialize, then the name_to_dev_t() interpretation will take precedence. These incompatibilities would only show up in really strange setups with bad practices so we shouldn't have to worry about them. Signed-off-by: Dan Ehrenberg <dehrenberg@chromium.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15dm: add 'use_blk_mq' module param and expose in per-device ro sysfs attrMike Snitzer
Request-based DM's blk-mq support defaults to off; but a user can easily change the default using the dm_mod.use_blk_mq module/boot option. Also, you can check what mode a given request-based DM device is using with: cat /sys/block/dm-X/dm/use_blk_mq This change enabled further cleanup and reduced work (e.g. the md->io_pool and md->rq_pool isn't created if using blk-mq). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15dm: add full blk-mq support to request-based DMMike Snitzer
Commit e5863d9ad ("dm: allocate requests in target when stacking on blk-mq devices") served as the first step toward fully utilizing blk-mq in request-based DM -- it enabled stacking an old-style (request_fn) request_queue ontop of the underlying blk-mq device(s). That first step didn't improve performance of DM multipath ontop of fast blk-mq devices (e.g. NVMe) because the top-level old-style request_queue was severely limited by the queue_lock. The second step offered here enables stacking a blk-mq request_queue ontop of the underlying blk-mq device(s). This unlocks significant performance gains on fast blk-mq devices, Keith Busch tested on his NVMe testbed and offered this really positive news: "Just providing a performance update. All my fio tests are getting roughly equal performance whether accessed through the raw block device or the multipath device mapper (~470k IOPS). I could only push ~20% of the raw iops through dm before this conversion, so this latest tree is looking really solid from a performance standpoint." Signed-off-by: Mike Snitzer <snitzer@redhat.com> Tested-by: Keith Busch <keith.busch@intel.com>
2015-03-31dm: remove request-based DM queue's lld_busy_fn hookMike Snitzer
DM multipath is the only caller of blk_lld_busy() -- which calls a queue's lld_busy_fn hook. Request-based DM doesn't support stacking multipath devices so there is no reason to register the lld_busy_fn hook on a multipath device's queue using blk_queue_lld_busy(). As such, remove functions dm_lld_busy and dm_table_any_busy_target. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-11dm: inherit QUEUE_FLAG_SG_GAPS flags from underlying queuesKeith Busch
A DM device must inherit the QUEUE_FLAG_SG_GAPS flags from its underlying block devices' request queues. This fixes problems when submitting cloned requests to multipathed devices requiring virtually contiguous buffers. Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09dm table: train hybrid target type detection to select blk-mq if appropriateMike Snitzer
Otherwise replacing the multipath target with the error target fails: device-mapper: ioctl: can't change device type after initial table load. The error target was mistakenly considered to be target type DM_TYPE_REQUEST_BASED rather than DM_TYPE_MQ_REQUEST_BASED even if the target it was to replace was of type DM_TYPE_MQ_REQUEST_BASED. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09dm: allocate requests in target when stacking on blk-mq devicesMike Snitzer
For blk-mq request-based DM the responsibility of allocating a cloned request is transfered from DM core to the target type. Doing so enables the cloned request to be allocated from the appropriate blk-mq request_queue's pool (only the DM target, e.g. multipath, can know which block device to send a given cloned request to). Care was taken to preserve compatibility with old-style block request completion that requires request-based DM _not_ acquire the clone request's queue lock in the completion path. As such, there are now 2 different request-based DM target_type interfaces: 1) the original .map_rq() interface will continue to be used for non-blk-mq devices -- the preallocated clone request is passed in from DM core. 2) a new .clone_and_map_rq() and .release_clone_rq() will be used for blk-mq devices -- blk_get_request() and blk_put_request() are used respectively from these hooks. dm_table_set_type() was updated to detect if the request-based target is being stacked on blk-mq devices, if so DM_TYPE_MQ_REQUEST_BASED is set. DM core disallows switching the DM table's type after it is set. This means that there is no mixing of non-blk-mq and blk-mq devices within the same request-based DM table. [This patch was started by Keith and later heavily modified by Mike] Tested-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-19dm: add presuspend_undo hook to target_typeMike Snitzer
The DM thin-pool target now must undo the changes performed during pool_presuspend() so introduce presuspend_undo hook in target_type. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-10-06dm: allow active and inactive tables to share dm_devsBenjamin Marzinski
Until this change, when loading a new DM table, DM core would re-open all of the devices in the DM table. Now, DM core will avoid redundant device opens (and closes when destroying the old table) if the old table already has a device open using the same mode. This is achieved by managing reference counts on the table_devices that DM core now stores in the mapped_device structure (rather than in the dm_table structure). So a mapped_device's active and inactive dm_tables' dm_dev lists now just point to the dm_devs stored in the mapped_device's table_devices list. This improvement in DM core's device reference counting has the side-effect of fixing a long-standing limitation of the multipath target: a DM multipath table couldn't include any paths that were unusable (failed). For example: if all paths have failed and you add a new, working, path to the table; you can't use it since the table load would fail due to it still containing failed paths. Now a re-load of a multipath table can include failed devices and when those devices become active again they can be used instantly. The device list code in dm.c isn't a straight copy/paste from the code in dm-table.c, but it's very close (aside from some variable renames). One subtle difference is that find_table_device for the tables_devices list will only match devices with the same name and mode. This is because we don't want to upgrade a device's mode in the active table when an inactive table is loaded. Access to the mapped_device structure's tables_devices list requires a mutex (tables_devices_lock), so that tables cannot be created and destroyed concurrently. Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-08-11dm table: propagate QUEUE_FLAG_NO_SG_MERGEJeff Moyer
Commit 05f1dd5 ("block: add queue flag for disabling SG merging") introduced a new queue flag: QUEUE_FLAG_NO_SG_MERGE. This gets set by default in blk_mq_init_queue for mq-enabled devices. The effect of the flag is to bypass the SG segment merging. Instead, the bio->bi_vcnt is used as the number of hardware segments. With a device mapper target on top of a device with QUEUE_FLAG_NO_SG_MERGE set, we can end up sending down more segments than a driver is prepared to handle. I ran into this when backporting the virtio_blk mq support. It triggerred this BUG_ON, in virtio_queue_rq: BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); The queue's max is set here: blk_queue_max_segments(q, vblk->sg_elems-2); Basically, what happens is that a bio is built up for the dm device (which does not have the QUEUE_FLAG_NO_SG_MERGE flag set) using bio_add_page. That path will call into __blk_recalc_rq_segments, so what you end up with is bi_phys_segments being much smaller than bi_vcnt (and bi_vcnt grows beyond the maximum sg elements). Then, when the bio is submitted, it gets cloned. When the cloned bio is submitted, it will end up in blk_recount_segments, here: if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags)) bio->bi_phys_segments = bio->bi_vcnt; and now we've set bio->bi_phys_segments to a number that is beyond what was registered as queue_max_segments by the driver. The right way to fix this is to propagate the queue flag up the stack. The rules for propagating the flag are simple: - if the flag is set for any underlying device, it must be set for the upper device - consequently, if the flag is not set for any underlying device, it should not be set for the upper device. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.16+
2014-08-01dm table: make dm_table_supports_discards staticMikulas Patocka
The function dm_table_supports_discards is only called from dm-table.c:dm_table_set_restrictions(). So move it above dm_table_set_restrictions and make it static. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-06-04dm: remove symbol export for dm_set_device_limitsMike Snitzer
There is no need for code other than DM core to use dm_set_device_limits so remove its EXPORT_SYMBOL_GPL. Also, cleanup a couple whitespace nits. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-27dm table: add dm_table_run_md_queue_asyncMike Snitzer
Introduce dm_table_run_md_queue_async() to run the request_queue of the mapped_device associated with a request-based DM table. Also add dm_md_get_queue() wrapper to extract the request_queue from a mapped_device. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
2014-03-27dm: make dm_table_alloc_md_mempools staticMikulas Patocka
Make the function dm_table_alloc_md_mempools static because it is not called from another file. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-01-07dm table: remove unused buggy code that extends the targets arrayMikulas Patocka
A device mapper table is allocated in the following way: * The function dm_table_create is called, it gets the number of targets as an argument -- it allocates a targets array accordingly. * For each target, we call dm_table_add_target. If we add more targets than were specified in dm_table_create, the function dm_table_add_target reallocates the targets array. However, this reallocation code is wrong - it moves the targets array to a new location, while some target constructors hold pointers to the array in the old location. The following DM target drivers save the pointer to the target structure, so they corrupt memory if the target array is moved: multipath, raid, mirror, snapshot, stripe, switch, thin, verity. Under normal circumstances, the reallocation function is not called (because dm_table_create is called with the correct number of targets), so the buggy reallocation code is not used. Prior to the fix "dm table: fail dm_table_create on dm_round_up overflow", the reallocation code could only be used in case the user specifies too large a value in param->target_count, such as 0xffffffff. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-12-10dm table: fail dm_table_create on dm_round_up overflowMikulas Patocka
The dm_round_up function may overflow to zero. In this case, dm_table_create() must fail rather than go on to allocate an empty array with alloc_targets(). This fixes a possible memory corruption that could be caused by passing too large a number in "param->target_count". Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2013-11-09dm table: print error on preresume failureMike Snitzer
If preresume fails it is worth logging an error given that a device is left suspended due to the failure. This change was motivated by local preresume error logging that was added to the cache target ("preresume failed"). Elevating this target-agnostic context for the where the target-specific error occurred relative to the DM core's callouts makes sense. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com>
2013-10-31dm: allocate buffer for messages with small number of arguments using GFP_NOIOMikulas Patocka
dm-mpath and dm-thin must process messages even if some device is suspended, so we allocate argv buffer with GFP_NOIO. These messages have a small fixed number of arguments. On the other hand, dm-switch needs to process bulk data using messages so excessive use of GFP_NOIO could cause trouble. The patch also lowers the default number of arguments from 64 to 8, so that there is smaller load on GFP_NOIO allocations. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Acked-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-09-06dm ioctl: increase granularity of type_lock when loading tableMike Snitzer
Hold the mapped device's type_lock before calling populate_table() since it is where the table's type is determined based on the specified targets. There is no need to allow concurrent table loads to race to establish the table's targets or type. This eliminates the need to grab the lock in dm_table_set_type(). Also verify that the type_lock is held in both dm_set_md_type() and dm_get_md_type(). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-09-06dm: allow error target to replace bio-based and request-based targetsMike Snitzer
It may be useful to switch a request-based table to the "error" target. Enhance the DM core to allow a hybrid target_type which is capable of handling either bios (via .map) or requests (via .map_rq). Add a request-based map function (.map_rq) to the "error" target_type; making it DM's first hybrid target. Train dm_table_set_type() to prefer the mapped device's established type (request-based or bio-based). If the mapped device doesn't have an established type default to making the table with the hybrid target(s) bio-based. Tested 'dmsetup wipe_table' to work on both bio-based and request-based devices. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Joe Jin <joe.jin@oracle.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Acked-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-10dm: optimize use SRCU and RCUMikulas Patocka
This patch removes "io_lock" and "map_lock" in struct mapped_device and "holders" in struct dm_table and replaces these mechanisms with sleepable-rcu. Previously, the code would call "dm_get_live_table" and "dm_table_put" to get and release table. Now, the code is changed to call "dm_get_live_table" and "dm_put_live_table". dm_get_live_table locks sleepable-rcu and dm_put_live_table unlocks it. dm_get_live_table_fast/dm_put_live_table_fast can be used instead of dm_get_live_table/dm_put_live_table. These *_fast functions use non-sleepable RCU, so the caller must not block between them. If the code changes active or inactive dm table, it must call dm_sync_table before destroying the old table. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10dm table: fix write same supportMike Snitzer
If device_not_write_same_capable() returns true then the iterate_devices loop in dm_table_supports_write_same() should return false. Reported-by: Bharata B Rao <bharata.rao@gmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # v3.8+ Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01dm: rename request variables to biosAlasdair G Kergon
Use 'bio' in the name of variables and functions that deal with bios rather than 'request' to avoid confusion with the normal block layer use of 'request'. No functional changes. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01dm table: remove superfluous variable resetWang Sheng-Hui
If allocation fails, the local var *t is not used any more after kfree. Don't need to reset it to NULL. Remove the unnecesary NULL set here. Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-12-21dm: introduce per_bio_dataMikulas Patocka
Introduce a field per_bio_data_size in struct dm_target. Targets can set this field in the constructor. If a target sets this field to a non-zero value, "per_bio_data_size" bytes of auxiliary data are allocated for each bio submitted to the target. These data can be used for any purpose by the target and help us improve performance by removing some per-target mempools. Per-bio data is accessed with dm_per_bio_data. The argument data_size must be the same as the value per_bio_data_size in dm_target. If the target has a pointer to per_bio_data, it can get a pointer to the bio with dm_bio_from_per_bio_data() function (data_size must be the same as the value passed to dm_per_bio_data). Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-12-21dm: prepare to support WRITE SAMEMike Snitzer
Allow targets to opt in to WRITE SAME support by setting 'num_write_same_requests' in the dm_target structure. A dm device will only advertise WRITE SAME support if all its targets and all its underlying devices support it. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-12-21dm: disable WRITE SAMEMike Snitzer
WRITE SAME bios are not yet handled correctly by device-mapper so disable their use on device-mapper devices by setting max_write_same_sectors to zero. As an example, a ciphertext device is incompatible because the data gets changed according to the location at which it written and so the dm crypt target cannot support it. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org Cc: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-09-26dm: retain table limits when swapping to new table with no devicesMike Snitzer
Add a safety net that will re-use the DM device's existing limits in the event that DM device has a temporary table that doesn't have any component devices. This is to reduce the chance that requests not respecting the hardware limits will reach the device. DM recalculates queue limits based only on devices which currently exist in the table. This creates a problem in the event all devices are temporarily removed such as all paths being lost in multipath. DM will reset the limits to the maximum permissible, which can then assemble requests which exceed the limits of the paths when the paths are restored. The request will fail the blk_rq_check_limits() test when sent to a path with lower limits, and will be retried without end by multipath. This became a much bigger issue after v3.6 commit fe86cdcef ("block: do not artificially constrain max_sectors for stacking drivers"). Reported-by: David Jeffery <djeffery@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-09-26dm table: clear add_random unless all devices have it setMilan Broz
Always clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not have it set. Otherwise devices with predictable characteristics may contribute entropy. QUEUE_FLAG_ADD_RANDOM specifies whether or not queue IO timings contribute to the random pool. For bio-based targets this flag is always 0 because such devices have no real queue. For request-based devices this flag was always set to 1 by default. Now set it according to the flags on underlying devices. If there is at least one device which should not contribute, set the flag to zero: If a device, such as fast SSD storage, is not suitable for supplying entropy, a request-based queue stacked over it will not be either. Because the checking logic is exactly same as for the rotational flag, share the iteration function with device_is_nonrot(). Signed-off-by: Milan Broz <mbroz@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-07-27dm: allow targets to request flushes regardless of underlying device supportJoe Thornber
Allow targets to override the 'supports flush' calculation. Set 'flush_supported' if a target needs to receive flushes regardless of whether or not its underlying devices have support. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-03-28dm: reject trailing characters in sccanf inputMikulas Patocka
Device mapper uses sscanf to convert arguments to numbers. The problem is that the way we use it ignores additional unmatched characters in the scanned string. For example, this `if (sscanf(string, "%d", &number) == 1)' will match a number, but also it will match number with some garbage appended, like "123abc". As a result, device mapper accepts garbage after some numbers. For example the command `dmsetup create vg1-new --table "0 16384 linear 254:1bla 34816bla"' will pass without an error. This patch fixes all sscanf uses in device mapper. It appends "%c" with a pointer to a dummy character variable to every sscanf statement. The construct `if (sscanf(string, "%d%c", &number, &dummy) == 1)' succeeds only if string is a null-terminated number (optionally preceded by some whitespace characters). If there is some character appended after the number, sscanf matches "%c", writes the character to the dummy variable and returns 2. We check the return value for 1 and consequently reject numbers with some garbage appended. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-03-28dm table: simplify call to free_devicesHannes Reinecke
free_devices in dm_table.c already uses list_for_each(), so we don't need to check if the list is empty. Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-01-11block: Introduce blk_set_stacking_limits functionMartin K. Petersen
Stacking driver queue limits are typically bounded exclusively by the capabilities of the low level devices, not by the stacking driver itself. This patch introduces blk_set_stacking_limits() which has more liberal metrics than the default queue limits function. This allows us to inherit topology parameters from bottom devices without manually tweaking the default limits in each driver prior to calling the stacking function. Since there is now a clear distinction between stacking and low-level devices, blk_set_default_limits() has been modified to carry the more conservative values that we used to manually set in blk_queue_make_request(). Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-10-31dm table: add immutable featureAlasdair G Kergon
Introduce DM_TARGET_IMMUTABLE to indicate that the target type cannot be mixed with any other target type, and once loaded into a device, it cannot be replaced with a table containing a different type. The thin provisioning pool device will use this. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-10-31dm table: add always writeable featureAlasdair G Kergon
Add a target feature flag DM_TARGET_ALWAYS_WRITEABLE to indicate that a target does not support read-only mode. The initial implementation of the thin provisioning target uses this. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-10-31dm table: add singleton featureAlasdair G Kergon
Introduce the concept of a singleton table which contains exactly one target. If a target type sets the DM_TARGET_SINGLETON feature bit device-mapper will ensure that any table that includes that target contains no others. The thin provisioning pool target uses this. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-10-31dm table: propagate non rotational flagMandeep Singh Baines
Allow QUEUE_FLAG_NONROT to propagate up the device stack if all underlying devices are non-rotational. Tools like ureadahead will schedule IOs differently based on the rotational flag. With this patch, I see boot time go from 7.75 s to 7.46 s on my device. Suggested-by: J. Richard Barnette <jrbarnette@chromium.org> Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: Neil Brown <neilb@suse.de> Cc: Jens Axboe <jaxboe@fusionio.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: dm-devel@redhat.com Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-09-25dm crypt: always disable discard_zeroes_dataMilan Broz
If optional discard support in dm-crypt is enabled, discards requests bypass the crypt queue and blocks of the underlying device are discarded. For the read path, discarded blocks are handled the same as normal ciphertext blocks, thus decrypted. So if the underlying device announces discarded regions return zeroes, dm-crypt must disable this flag because after decryption there is just random noise instead of zeroes. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-09-25dm table: avoid crash if integrity profile changesMike Snitzer
Commit a63a5cf (dm: improve block integrity support) introduced a two-phase initialization of a DM device's integrity profile. This patch avoids dereferencing a NULL 'template_disk' pointer in blk_integrity_register() if there is an integrity profile mismatch in dm_table_set_integrity(). This can occur if the integrity profiles for stacked devices in a DM table are changed between the call to dm_table_prealloc_integrity() and dm_table_set_integrity(). Reported-by: Zdenek Kabelac <zkabelac@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@kernel.org # 2.6.39
2011-08-02dm table: set flush capability based on underlying devicesMike Snitzer
DM has always advertised both REQ_FLUSH and REQ_FUA flush capabilities regardless of whether or not a given DM device's underlying devices also advertised a need for them. Block's flush-merge changes from 2.6.39 have proven to be more costly for DM devices. Performance regressions have been reported even when DM's underlying devices do not advertise that they have a write cache. Fix the performance regressions by configuring a DM device's flushing capabilities based on those of the underlying devices' capabilities. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-08-02dm table: share target argument parsing functionsMike Snitzer
Move multipath target argument parsing code into dm-table so other targets can share it. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-08-02dm: ignore merge_bvec for snapshots when safeMikulas Patocka
Add a new flag DMF_MERGE_IS_OPTIONAL to struct mapped_device to indicate whether the device can accept bios larger than the size its merge function returns. When set, use this to send large bios to snapshots which can split them if necessary. Snapshot I/O may be significantly fragmented and this approach seems to improve peformance. Before the patch, dm_set_device_limits restricted bio size to page size if the underlying device had a merge function and the target didn't provide a merge function. After the patch, dm_set_device_limits restricts bio size to page size if the underlying device has a merge function, doesn't have DMF_MERGE_IS_OPTIONAL flag and the target doesn't provide a merge function. The snapshot target can't provide a merge function because when the merge function is called, it is impossible to determine where the bio will be remapped. Previously this led us to impose a 4k limit, which we can now remove if the snapshot store is located on a device without a merge function. Together with another patch for optimizing full chunk writes, it improves performance from 29MB/s to 40MB/s when writing to the filesystem on snapshot store. If the snapshot store is placed on a non-dm device with a merge function (such as md-raid), device mapper still limits all bios to page size. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-08-02dm table: clean dm_get_device and move exportsMike Snitzer
There is no need for __table_get_device to be factored out. Also move the exports to the end of their respective functions. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>