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* dm: optimize use SRCU and RCUMikulas Patocka2013-07-101-35/+0
| | | | | | | | | | | | | | | | | | | | | | 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>
* dm table: fix write same supportMike Snitzer2013-05-101-1/+1
| | | | | | | | | | 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>
* dm: rename request variables to biosAlasdair G Kergon2013-03-011-5/+5
| | | | | | | | | | 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>
* dm table: remove superfluous variable resetWang Sheng-Hui2013-03-011-1/+0
| | | | | | | | 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>
* dm: introduce per_bio_dataMikulas Patocka2012-12-211-1/+10
| | | | | | | | | | | | | | | | | | | | | 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>
* dm: prepare to support WRITE SAMEMike Snitzer2012-12-211-1/+29
| | | | | | | | | | | 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>
* dm: disable WRITE SAMEMike Snitzer2012-12-211-0/+2
| | | | | | | | | | | | | | | 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>
* dm: retain table limits when swapping to new table with no devicesMike Snitzer2012-09-261-0/+35
| | | | | | | | | | | | | | | | | | | | | | 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>
* dm table: clear add_random unless all devices have it setMilan Broz2012-09-261-4/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* dm: allow targets to request flushes regardless of underlying device supportJoe Thornber2012-07-271-0/+3
| | | | | | | | | | | 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>
* dm: reject trailing characters in sccanf inputMikulas Patocka2012-03-281-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* dm table: simplify call to free_devicesHannes Reinecke2012-03-281-2/+1
| | | | | | | | 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>
* block: Introduce blk_set_stacking_limits functionMartin K. Petersen2012-01-111-3/+3
| | | | | | | | | | | | | | | | | | | | | 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>
* dm table: add immutable featureAlasdair G Kergon2011-10-311-0/+21
| | | | | | | | | | 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>
* dm table: add always writeable featureAlasdair G Kergon2011-10-311-0/+6
| | | | | | | | | 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>
* dm table: add singleton featureAlasdair G Kergon2011-10-311-0/+16
| | | | | | | | | | | 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>
* dm table: propagate non rotational flagMandeep Singh Baines2011-10-311-0/+30
| | | | | | | | | | | | | | | | | 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>
* dm crypt: always disable discard_zeroes_dataMilan Broz2011-09-251-0/+19
| | | | | | | | | | | | | | 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>
* dm table: avoid crash if integrity profile changesMike Snitzer2011-09-251-6/+7
| | | | | | | | | | | | | | | | | 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
* dm table: set flush capability based on underlying devicesMike Snitzer2011-08-021-0/+43
| | | | | | | | | | | | | | | | 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>
* dm table: share target argument parsing functionsMike Snitzer2011-08-021-0/+57
| | | | | | | | 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>
* dm: ignore merge_bvec for snapshots when safeMikulas Patocka2011-08-021-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* dm table: clean dm_get_device and move exportsMike Snitzer2011-08-021-20/+13
| | | | | | | | 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>
* dm: use vzallocJoe Perches2011-08-021-3/+1
| | | | | | | Use vzalloc() instead of vmalloc()+memset(). Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm table: fix discard supportMike Snitzer2011-08-021-8/+7
| | | | | | | | | | | | | | | | | | | | Remove 'discards_supported' from the dm_table structure. The same information can be easily discovered from the table's target(s) in dm_table_supports_discards(). Before this fix dm_table_supports_discards() would skip checking the individual targets' 'discards_supported' flag if any one target in the table didn't set num_discard_requests > 0. Now the per-target 'discards_supported' flag is effective at insuring the final DM device advertises discard support. But, to be clear, targets that don't support discards (!num_discard_requests) will not receive discard requests. Also DMWARN if a target sets 'discards_supported' override but forgets to set 'num_discard_requests'. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* atomic: use <linux/atomic.h>Arun Sharma2011-07-261-1/+1
| | | | | | | | | | | | | | This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: Arun Sharma <asharma@fb.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dm table: reject devices without request fnsMilan Broz2011-05-291-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds a check that a block device has a request function defined before it is used. Otherwise, misconfiguration can cause an oops. Because we are allowing devices with zero size e.g. an offline multipath device as in commit 2cd54d9bedb79a97f014e86c0da393416b264eb3 ("dm: allow offline devices") there needs to be an additional check to ensure devices are initialised. Some block devices, like a loop device without a backing file, exist but have no request function. Reproducer is trivial: dm-mirror on unbound loop device (no backing file on loop devices) dmsetup create x --table "0 8 mirror core 2 8 sync 2 /dev/loop0 0 /dev/loop1 0" and mirror resync will immediatelly cause OOps. BUG: unable to handle kernel NULL pointer dereference at (null) ? generic_make_request+0x2bd/0x590 ? kmem_cache_alloc+0xad/0x190 submit_bio+0x53/0xe0 ? bio_add_page+0x3b/0x50 dispatch_io+0x1ca/0x210 [dm_mod] ? read_callback+0x0/0xd0 [dm_mirror] dm_io+0xbb/0x290 [dm_mod] do_mirror+0x1e0/0x748 [dm_mirror] Signed-off-by: Milan Broz <mbroz@redhat.com> Reported-by: Zdenek Kabelac <zkabelac@redhat.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@kernel.org Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm table: allow targets to support discards internallyMike Snitzer2011-05-291-1/+5
| | | | | | | | Permit a target to support discards regardless of whether or not all its underlying devices do. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: improve block integrity supportMike Snitzer2011-04-051-34/+80
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current block integrity (DIF/DIX) support in DM is verifying that all devices' integrity profiles match during DM device resume (which is past the point of no return). To some degree that is unavoidable (stacked DM devices force this late checking). But for most DM devices (which aren't stacking on other DM devices) the ideal time to verify all integrity profiles match is during table load. Introduce the notion of an "initialized" integrity profile: a profile that was blk_integrity_register()'d with a non-NULL 'blk_integrity' template. Add blk_integrity_is_initialized() to allow checking if a profile was initialized. Update DM integrity support to: - check all devices with _initialized_ integrity profiles match during table load; uninitialized profiles (e.g. for underlying DM device(s) of a stacked DM device) are ignored. - disallow a table load that would result in an integrity profile that conflicts with a DM device's existing (in-use) integrity profile - avoid clearing an existing integrity profile - validate all integrity profiles match during resume; but if they don't all we can do is report the mismatch (during resume we're past the point of no return) Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: Require subsystems to explicitly allocate bio_set integrity mempoolMartin K. Petersen2011-03-171-2/+5
| | | | | | | | | | | | | | | | | | MD and DM create a new bio_set for every metadevice. Each bio_set has an integrity mempool attached regardless of whether the metadevice is capable of passing integrity metadata. This is a waste of memory. Instead we defer the allocation decision to MD and DM since we know at metadevice creation time whether integrity passthrough is needed or not. Automatic integrity mempool allocation can then be removed from bioset_create() and we make an explicit integrity allocation for the fs_bio_set. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reported-by: Zdenek Kabelac <zkabelac@redhat.com> Acked-by: Mike Snitzer <snizer@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: remove per-queue pluggingJens Axboe2011-03-101-24/+0
| | | | | | | | Code has been converted over to the new explicit on-stack plugging, and delay users have been converted to use the new API for that. So lets kill off the old plugging along with aops->sync_page(). Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: restore multiple bd_link_disk_holder() supportTejun Heo2011-01-141-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | Commit e09b457b (block: simplify holder symlink handling) incorrectly assumed that there is only one link at maximum. dm may use multiple links and expects block layer to track reference count for each link, which is different from and unrelated to the exclusive device holder identified by @holder when the device is opened. Remove the single holder assumption and automatic removal of the link and revive the per-link reference count tracking. The code essentially behaves the same as before commit e09b457b sans the unnecessary kobject reference count dancing. While at it, note that this facility should not be used by anyone else than the current ones. Sysfs symlinks shouldn't be abused like this and the whole thing doesn't belong in the block layer at all. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Milan Broz <mbroz@redhat.com> Cc: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Neil Brown <neilb@suse.de> Cc: linux-raid@vger.kernel.org Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* dm: per target unplug callback supportNeilBrown2011-01-131-0/+5
| | | | | | | | | | Add per-target unplug callback support. Cc: linux-raid@vger.kernel.org Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: introduce target callbacks and congestion callbackNeilBrown2011-01-131-0/+14
| | | | | | | | | | | | | | | | | | DM currently implements congestion checking by checking on congestion in each component device. For raid456 we need to also check if the stripe cache is congested. Add per-target congestion checker callback support. Extending the target_callbacks structure with additional callback functions allows for establishing multiple callbacks per-target (a callback is also needed for unplug). Cc: linux-raid@vger.kernel.org Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds2011-01-131-9/+11
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block: (43 commits) block: ensure that completion error gets properly traced blktrace: add missing probe argument to block_bio_complete block cfq: don't use atomic_t for cfq_group block cfq: don't use atomic_t for cfq_queue block: trace event block fix unassigned field block: add internal hd part table references block: fix accounting bug on cross partition merges kref: add kref_test_and_get bio-integrity: mark kintegrityd_wq highpri and CPU intensive block: make kblockd_workqueue smarter Revert "sd: implement sd_check_events()" block: Clean up exit_io_context() source code. Fix compile warnings due to missing removal of a 'ret' variable fs/block: type signature of major_to_index(int) to major_to_index(unsigned) block: convert !IS_ERR(p) && p to !IS_ERR_NOR_NULL(p) cfq-iosched: don't check cfqg in choose_service_tree() fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors cdrom: export cdrom_check_events() sd: implement sd_check_events() sr: implement sr_check_events() ...
| * block: clean up blkdev_get() wrappers and their usersTejun Heo2010-11-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After recent blkdev_get() modifications, open_by_devnum() and open_bdev_exclusive() are simple wrappers around blkdev_get(). Replace them with blkdev_get_by_dev() and blkdev_get_by_path(). blkdev_get_by_dev() is identical to open_by_devnum(). blkdev_get_by_path() is slightly different in that it doesn't automatically add %FMODE_EXCL to @mode. All users are converted. Most conversions are mechanical and don't introduce any behavior difference. There are several exceptions. * btrfs now sets FMODE_EXCL in btrfs_device->mode, so there's no reason to OR it explicitly on blkdev_put(). * gfs2, nilfs2 and the generic mount_bdev() now set FMODE_EXCL in sb->s_mode. * With the above changes, sb->s_mode now always should contain FMODE_EXCL. WARN_ON_ONCE() added to kill_block_super() to detect errors. The new blkdev_get_*() functions are with proper docbook comments. While at it, add function description to blkdev_get() too. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: Neil Brown <neilb@suse.de> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Joern Engel <joern@lazybastard.org> Cc: Chris Mason <chris.mason@oracle.com> Cc: Jan Kara <jack@suse.cz> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: reiserfs-devel@vger.kernel.org Cc: xfs-masters@oss.sgi.com Cc: Alexander Viro <viro@zeniv.linux.org.uk>
| * block: make blkdev_get/put() handle exclusive accessTejun Heo2010-11-131-12/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Over time, block layer has accumulated a set of APIs dealing with bdev open, close, claim and release. * blkdev_get/put() are the primary open and close functions. * bd_claim/release() deal with exclusive open. * open/close_bdev_exclusive() are combination of open and claim and the other way around, respectively. * bd_link/unlink_disk_holder() to create and remove holder/slave symlinks. * open_by_devnum() wraps bdget() + blkdev_get(). The interface is a bit confusing and the decoupling of open and claim makes it impossible to properly guarantee exclusive access as in-kernel open + claim sequence can disturb the existing exclusive open even before the block layer knows the current open if for another exclusive access. Reorganize the interface such that, * blkdev_get() is extended to include exclusive access management. @holder argument is added and, if is @FMODE_EXCL specified, it will gain exclusive access atomically w.r.t. other exclusive accesses. * blkdev_put() is similarly extended. It now takes @mode argument and if @FMODE_EXCL is set, it releases an exclusive access. Also, when the last exclusive claim is released, the holder/slave symlinks are removed automatically. * bd_claim/release() and close_bdev_exclusive() are no longer necessary and either made static or removed. * bd_link_disk_holder() remains the same but bd_unlink_disk_holder() is no longer necessary and removed. * open_bdev_exclusive() becomes a simple wrapper around lookup_bdev() and blkdev_get(). It also has an unexpected extra bdev_read_only() test which probably should be moved into blkdev_get(). * open_by_devnum() is modified to take @holder argument and pass it to blkdev_get(). Most of bdev open/close operations are unified into blkdev_get/put() and most exclusive accesses are tested atomically at the open time (as it should). This cleans up code and removes some, both valid and invalid, but unnecessary all the same, corner cases. open_bdev_exclusive() and open_by_devnum() can use further cleanup - rename to blkdev_get_by_path() and blkdev_get_by_devt() and drop special features. Well, let's leave them for another day. Most conversions are straight-forward. drbd conversion is a bit more involved as there was some reordering, but the logic should stay the same. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Neil Brown <neilb@suse.de> Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Acked-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Philipp Reisner <philipp.reisner@linbit.com> Cc: Peter Osterlund <petero2@telia.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Jan Kara <jack@suse.cz> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <joel.becker@oracle.com> Cc: Alex Elder <aelder@sgi.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: dm-devel@redhat.com Cc: drbd-dev@lists.linbit.com Cc: Leo Chen <leochen@broadcom.com> Cc: Scott Branden <sbranden@broadcom.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com> Cc: Joern Engel <joern@logfs.org> Cc: reiserfs-devel@vger.kernel.org Cc: Alexander Viro <viro@zeniv.linux.org.uk>
| * block: simplify holder symlink handlingTejun Heo2010-11-131-6/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Code to manage symlinks in /sys/block/*/{holders|slaves} are overly complex with multiple holder considerations, redundant extra references to all involved kobjects, unused generic kobject holder support and unnecessary mixup with bd_claim/release functionalities. Strip it down to what's necessary (single gendisk holder) and make it use a separate interface. This is a step for cleaning up bd_claim/release. This patch makes dm-table slightly more complex but it will be simplified again with further changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Neil Brown <neilb@suse.de> Acked-by: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com
* | block: max hardware sectors limit wrapperMike Snitzer2010-12-171-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement blk_limits_max_hw_sectors() and make blk_queue_max_hw_sectors() a wrapper around it. DM needs this to avoid setting queue_limits' max_hw_sectors and max_sectors directly. dm_set_device_limits() now leverages blk_limits_max_hw_sectors() logic to establish the appropriate max_hw_sectors minimum (PAGE_SIZE). Fixes issue where DM was incorrectly setting max_sectors rather than max_hw_sectors (which caused dm_merge_bvec()'s max_hw_sectors check to be ineffective). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@kernel.org Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | block: Deprecate QUEUE_FLAG_CLUSTER and use queue_limits insteadMartin K. Petersen2010-12-171-5/+0
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | When stacking devices, a request_queue is not always available. This forced us to have a no_cluster flag in the queue_limits that could be used as a carrier until the request_queue had been set up for a metadevice. There were several problems with that approach. First of all it was up to the stacking device to remember to set queue flag after stacking had completed. Also, the queue flag and the queue limits had to be kept in sync at all times. We got that wrong, which could lead to us issuing commands that went beyond the max scatterlist limit set by the driver. The proper fix is to avoid having two flags for tracking the same thing. We deprecate QUEUE_FLAG_CLUSTER and use the queue limit directly in the block layer merging functions. The queue_limit 'no_cluster' is turned into 'cluster' to avoid double negatives and to ease stacking. Clustering defaults to being enabled as before. The queue flag logic is removed from the stacking function, and explicitly setting the cluster flag is no longer necessary in DM and MD. Reported-by: Ed Lin <ed.lin@promise.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* Consolidate min_not_zeroMartin K. Petersen2010-09-101-5/+0
| | | | | | | | We have several users of min_not_zero, each of them using their own definition. Move the define to kernel.h. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>
* dm: linear support discardMike Snitzer2010-08-121-0/+44
| | | | | | | | | | | | | | | | | Allow discards to be passed through to linear mappings if at least one underlying device supports it. Discards will be forwarded only to devices that support them. A target that supports discards should set num_discard_requests to indicate how many times each discard request must be submitted to it. Verify table's underlying devices support discards prior to setting the associated DM device as capable of discards (via QUEUE_FLAG_DISCARD). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Joe Thornber <thornber@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm ioctl: refactor dm_table_completeWill Drewry2010-08-121-3/+52
| | | | | | | | | This change unifies the various checks and finalization that occurs on a table prior to use. By doing so, it allows table construction without traversing the dm-ioctl interface. Signed-off-by: Will Drewry <wad@chromium.org> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm table: remove unused dm_get_device range parametersNikanth Karthikesan2010-03-061-6/+4
| | | | | | | | Remove unused parameters(start and len) of dm_get_device() and fix the callers. Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm table: remove dm_get from dm_table_get_mdKiyoshi Ueda2010-03-061-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the dm_get() in dm_table_get_md() because dm_table_get_md() could be called from presuspend/postsuspend, which are called while mapped_device is in DMF_FREEING state, where dm_get() is not allowed. Justification for that is the lifetime of both objects: As far as the current dm design/implementation, mapped_device is never freed while targets are doing something, because dm core waits for targets to become quiet in dm_put() using presuspend/postsuspend. So targets should be able to touch mapped_device without holding reference count of the mapped_device, and we should allow targets to touch mapped_device even if it is in DMF_FREEING state. Backgrounds: I'm trying to remove the multipath internal queue, since dm core now has a generic queue for request-based dm. In the patch-set, the multipath target wants to request dm core to start/stop queue. One of such start/stop requests can happen during postsuspend() while the target waits for pg-init to complete, because the target stops queue when starting pg-init and tries to restart it when completing pg-init. Since queue belongs to mapped_device, it involves calling dm_table_get_md() and dm_put(). On the other hand, postsuspend() is called in dm_put() for mapped_device which is in DMF_FREEING state, and that triggers BUG_ON(DMF_FREEING) in the 2nd dm_put(). I had tried to solve this problem by changing only multipath not to touch mapped_device which is in DMF_FREEING state, but I couldn't and I came up with a question why we need dm_get() in dm_table_get_md(). Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* DM: Fix device mapper topology stackingMartin K. Petersen2010-01-111-15/+5
| | | | | | | | | | | | | | Make DM use bdev_stack_limits() function so that partition offsets get taken into account when calculating alignment. Clarify stacking warnings. Also remove obsolete clearing of final alignment_offset and misalignment flag. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: Alasdair G. Kergon <agk@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dmLinus Torvalds2009-12-151-0/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm: (80 commits) dm snapshot: use merge origin if snapshot invalid dm snapshot: report merge failure in status dm snapshot: merge consecutive chunks together dm snapshot: trigger exceptions in remaining snapshots during merge dm snapshot: delay merging a chunk until writes to it complete dm snapshot: queue writes to chunks being merged dm snapshot: add merging dm snapshot: permit only one merge at once dm snapshot: support barriers in snapshot merge target dm snapshot: avoid allocating exceptions in merge dm snapshot: rework writing to origin dm snapshot: add merge target dm exception store: add merge specific methods dm snapshot: create function for chunk_is_tracked wait dm snapshot: make bio optional in __origin_write dm mpath: reject messages when device is suspended dm: export suspended state to targets dm: rename dm_suspended to dm_suspended_md dm: swap target postsuspend call and setting suspended flag dm crypt: add plain64 iv ...
| * dm: bind new table before destroying oldAlasdair G Kergon2009-12-101-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When replacing a mapped device's table during a 'resume', delay the destruction of the old table until the new one is successfully in place. This will make it easier for a later patch to transfer internal state information from the old table to the new one (something we do not currently support) while giving us more options for reversion if a later part of the operation fails. Devices are always in the suspended state during dm_swap_table(). This patch reinforces the requirement that all I/O must have been flushed from the table targets while in this state (including any in workqueues). In the case of 'noflush' suspending, unprocessed I/O should have been 'pushed back' to the dm core prior to this point, for resubmission after the new table is in place. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | tree-wide: convert open calls to remove spaces to skip_spaces() lib functionAndré Goddard Rosa2009-12-151-4/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dm stripe: expose correct io hintsMike Snitzer2009-09-041-0/+4
| | | | | | | | | | | | | Set sensible I/O hints for striped DM devices in the topology infrastructure added for 2.6.31 for userspace tools to obtain via sysfs. Add .io_hints to 'struct target_type' to allow the I/O hints portion (io_min and io_opt) of the 'struct queue_limits' to be set by each target and implement this for dm-stripe. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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