Commit Graph

55 Commits

Author SHA1 Message Date
Qi Zheng cf2e309ebc mm: shrinkers: convert shrinker_rwsem to mutex
Now there are no readers of shrinker_rwsem, so we can simply replace it
with mutex lock.

Link: https://lkml.kernel.org/r/20230313112819.38938-9-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <tkhai@ya.ru>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28 16:20:17 -07:00
Heinz Mauelshagen 1c13188669 dm: prefer '"%s...", __func__'
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:07 -05:00
Heinz Mauelshagen 0ef0b4717a dm: add missing empty lines
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:06 -05:00
Heinz Mauelshagen a4a82ce3d2 dm: correct block comments format.
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:06 -05:00
Heinz Mauelshagen 96422281ba dm: address space issues relative to switch/while/for/...
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:06 -05:00
Heinz Mauelshagen 86a3238c7b dm: change "unsigned" to "unsigned int"
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:06 -05:00
Heinz Mauelshagen 3bd9400307 dm: add missing SPDX-License-Indentifiers
'GPL-2.0-only' is used instead of 'GPL-2.0' because SPDX has
deprecated its use.

Suggested-by: John Wiele <jwiele@redhat.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:06 -05:00
Mike Snitzer 352b837a55 dm cache: Fix ABBA deadlock between shrink_slab and dm_cache_metadata_abort
Same ABBA deadlock pattern fixed in commit 4b60f452ec51 ("dm thin: Fix
ABBA deadlock between shrink_slab and dm_pool_abort_metadata") to
DM-cache's metadata.

Reported-by: Zhihao Cheng <chengzhihao1@huawei.com>
Cc: stable@vger.kernel.org
Fixes: 028ae9f76f ("dm cache: add fail io mode and needs_check flag")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-12-01 11:42:45 -05:00
Guo Zhengkui d254c3699f dm cache metadata: remove unnecessary variable in __dump_mapping
Fix the following coccicheck warning:

drivers/md/dm-cache-metadata.c:1512:5-6: Unneeded variable: "r".
Return "0" on line 1520.

Signed-off-by: Guo Zhengkui <guozhengkui@vivo.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-05-09 15:40:10 -04:00
Christoph Hellwig 6dcbb52cdd dm: use bdev_nr_sectors and bdev_nr_bytes instead of open coding them
Use the proper helpers to read the block device size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20211018101130.1838532-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:43:22 -06:00
Christoph Hellwig 1e0dcca9e1 dm: use bdev_read_only to check if a device is read-only
dm-thin and dm-cache also work on partitions, so use the proper
interface to check if the device is read-only.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-24 18:15:57 -07:00
Ye Bin d16ff19e69 dm cache metadata: Avoid returning cmd->bm wild pointer on error
Maybe __create_persistent_data_objects() caller will use PTR_ERR as a
pointer, it will lead to some strange things.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-09-02 13:38:24 -04:00
Nikos Tsironis e28adc3bf3 dm cache metadata: Fix loading discard bitset
Add missing dm_bitset_cursor_next() to properly advance the bitset
cursor.

Otherwise, the discarded state of all blocks is set according to the
discarded state of the first block.

Fixes: ae4a46a1f6 ("dm cache metadata: use bitset cursor api to load discard bitset")
Cc: stable@vger.kernel.org
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-04-18 16:18:25 -04:00
Mike Snitzer 687cf4412a dm cache metadata: verify cache has blocks in blocks_are_clean_separate_dirty()
Otherwise dm_bitset_cursor_begin() return -ENODATA.  Other calls to
dm_bitset_cursor_begin() have similar negative checks.

Fixes inability to create a cache in passthrough mode (even though doing
so makes no sense).

Fixes: 0d963b6e65 ("dm cache metadata: fix metadata2 format's blocks_are_clean_separate_dirty")
Cc: stable@vger.kernel.org
Reported-by: David Teigland <teigland@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-07 16:04:09 -05:00
Joe Thornber 4561ffca88 dm cache metadata: ignore hints array being too small during resize
Commit fd2fa9541 ("dm cache metadata: save in-core policy_hint_size to
on-disk superblock") enabled previously written policy hints to be
used after a cache is reactivated.  But in doing so the cache
metadata's hint array was left exposed to out of bounds access because
on resize the metadata's on-disk hint array wasn't ever extended.

Fix this by ignoring that there are no on-disk hints associated with the
newly added cache blocks.  An expanded on-disk hint array is later
rewritten upon the next clean shutdown of the cache.

Fixes: fd2fa9541 ("dm cache metadata: save in-core policy_hint_size to on-disk superblock")
Cc: stable@vger.kernel.org
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-10-04 15:20:51 -04:00
Ilya Dryomov 5b1fe7bec8 dm cache metadata: set dirty on all cache blocks after a crash
Quoting Documentation/device-mapper/cache.txt:

  The 'dirty' state for a cache block changes far too frequently for us
  to keep updating it on the fly.  So we treat it as a hint.  In normal
  operation it will be written when the dm device is suspended.  If the
  system crashes all cache blocks will be assumed dirty when restarted.

This got broken in commit f177940a80 ("dm cache metadata: switch to
using the new cursor api for loading metadata") in 4.9, which removed
the code that consulted cmd->clean_when_opened (CLEAN_SHUTDOWN on-disk
flag) when loading cache blocks.  This results in data corruption on an
unclean shutdown with dirty cache blocks on the fast device.  After the
crash those blocks are considered clean and may get evicted from the
cache at any time.  This can be demonstrated by doing a lot of reads
to trigger individual evictions, but uncache is more predictable:

  ### Disable auto-activation in lvm.conf to be able to do uncache in
  ### time (i.e. see uncache doing flushing) when the fix is applied.

  # xfs_io -d -c 'pwrite -b 4M -S 0xaa 0 1G' /dev/vdb
  # vgcreate vg_cache /dev/vdb /dev/vdc
  # lvcreate -L 1G -n lv_slowdev vg_cache /dev/vdb
  # lvcreate -L 512M -n lv_cachedev vg_cache /dev/vdc
  # lvcreate -L 256M -n lv_metadev vg_cache /dev/vdc
  # lvconvert --type cache-pool --cachemode writeback vg_cache/lv_cachedev --poolmetadata vg_cache/lv_metadev
  # lvconvert --type cache vg_cache/lv_slowdev --cachepool vg_cache/lv_cachedev
  # xfs_io -d -c 'pwrite -b 4M -S 0xbb 0 512M' /dev/mapper/vg_cache-lv_slowdev
  # xfs_io -d -c 'pread -v 254M 512' /dev/mapper/vg_cache-lv_slowdev | head -n 2
  0fe00000:  bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb  ................
  0fe00010:  bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb  ................
  # dmsetup status vg_cache-lv_slowdev
  0 2097152 cache 8 27/65536 128 8192/8192 1 100 0 0 0 8192 7065 2 metadata2 writeback 2 migration_threshold 2048 smq 0 rw -
                                                            ^^^^
                                7065 * 64k = 441M yet to be written to the slow device
  # echo b >/proc/sysrq-trigger

  # vgchange -ay vg_cache
  # xfs_io -d -c 'pread -v 254M 512' /dev/mapper/vg_cache-lv_slowdev | head -n 2
  0fe00000:  bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb  ................
  0fe00010:  bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb  ................
  # lvconvert --uncache vg_cache/lv_slowdev
  Flushing 0 blocks for cache vg_cache/lv_slowdev.
  Logical volume "lv_cachedev" successfully removed
  Logical volume vg_cache/lv_slowdev is not cached.
  # xfs_io -d -c 'pread -v 254M 512' /dev/mapper/vg_cache-lv_slowdev | head -n 2
  0fe00000:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
  0fe00010:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................

This is the case with both v1 and v2 cache pool metatata formats.

After applying this patch:

  # vgchange -ay vg_cache
  # xfs_io -d -c 'pread -v 254M 512' /dev/mapper/vg_cache-lv_slowdev | head -n 2
  0fe00000:  bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb  ................
  0fe00010:  bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb  ................
  # lvconvert --uncache vg_cache/lv_slowdev
  Flushing 3724 blocks for cache vg_cache/lv_slowdev.
  ...
  Flushing 71 blocks for cache vg_cache/lv_slowdev.
  Logical volume "lv_cachedev" successfully removed
  Logical volume vg_cache/lv_slowdev is not cached.
  # xfs_io -d -c 'pread -v 254M 512' /dev/mapper/vg_cache-lv_slowdev | head -n 2
  0fe00000:  bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb  ................
  0fe00010:  bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb  ................

Cc: stable@vger.kernel.org
Fixes: f177940a80 ("dm cache metadata: switch to using the new cursor api for loading metadata")
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-08-09 12:14:32 -04:00
Mike Snitzer fd2fa95416 dm cache metadata: save in-core policy_hint_size to on-disk superblock
policy_hint_size starts as 0 during __write_initial_superblock().  It
isn't until the policy is loaded that policy_hint_size is set in-core
(cmd->policy_hint_size).  But it never got recorded in the on-disk
superblock because __commit_transaction() didn't deal with transfering
the in-core cmd->policy_hint_size to the on-disk superblock.

The in-core cmd->policy_hint_size gets initialized by metadata_open()'s
__begin_transaction_flags() which re-reads all superblock fields.
Because the superblock's policy_hint_size was never properly stored, when
the cache was created, hints_array_available() would always return false
when re-activating a previously created cache.  This means
__load_mappings() always considered the hints invalid and never made use
of the hints (these hints served to optimize).

Another detremental side-effect of this oversight is the cache_check
utility would fail with: "invalid hint width: 0"

Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-08-07 14:30:30 -04:00
Elena Reshetova 6bdd079610 dm cache: convert dm_cache_metadata.ref_count from atomic_t to refcount_t
atomic_t variables are currently used to implement reference
counters with the following properties:
 - counter is initialized to 1 using atomic_set()
 - a resource is freed upon counter reaching zero
 - once counter reaches zero, its further
   increments aren't allowed
 - counter schema uses basic atomic operations
   (set, inc, inc_not_zero, dec_and_test, etc.)

Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.

The variable dm_cache_metadata.ref_count is used as pure reference counter.
Convert it to refcount_t and fix up the operations.

Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-10-24 15:09:51 -04:00
Mike Snitzer 10add84e27 dm cache metadata: fail operations if fail_io mode has been established
Otherwise it is possible to trigger crashes due to the metadata being
inaccessible yet these methods don't safely account for that possibility
without these checks.

Cc: stable@vger.kernel.org
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-05-05 14:40:13 -04:00
Linus Torvalds d35a878ae1 - A major update for DM cache that reduces the latency for deciding
whether blocks should migrate to/from the cache.  The bio-prison-v2
   interface supports this improvement by enabling direct dispatch of
   work to workqueues rather than having to delay the actual work
   dispatch to the DM cache core.  So the dm-cache policies are much more
   nimble by being able to drive IO as they see fit.  One immediate
   benefit from the improved latency is a cache that should be much more
   adaptive to changing workloads.
 
 - Add a new DM integrity target that emulates a block device that has
   additional per-sector tags that can be used for storing integrity
   information.
 
 - Add a new authenticated encryption feature to the DM crypt target that
   builds on the capabilities provided by the DM integrity target.
 
 - Add MD interface for switching the raid4/5/6 journal mode and update
   the DM raid target to use it to enable aid4/5/6 journal write-back
   support.
 
 - Switch the DM verity target over to using the asynchronous hash crypto
   API (this helps work better with architectures that have access to
   off-CPU algorithm providers, which should reduce CPU utilization).
 
 - Various request-based DM and DM multipath fixes and improvements from
   Bart and Christoph.
 
 - A DM thinp target fix for a bio structure leak that occurs for each
   discard IFF discard passdown is enabled.
 
 - A fix for a possible deadlock in DM bufio and a fix to re-check the
   new buffer allocation watermark in the face of competing admin changes
   to the 'max_cache_size_bytes' tunable.
 
 - A couple DM core cleanups.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQEcBAABAgAGBQJZB6vtAAoJEMUj8QotnQNaoicIALuZTLElgAzxzA28cfk1+1Ea
 Gd09CfJ3M6cvk/YGUU7WwiSYIwu16yOJALG4sLcYnEmUCzvKfFPcl/RpeSJHPpYM
 0aVXa6NIJw7K2r3C17toiK2DRMHYw6QU843WeWI93vBW13lDJklNJL9fM7GBEOLH
 NMSNw2mAq9ajtLlnJhM3ZfhloA7/u/jektvlBO1AA3RQ5Kx1cXVXFPqN7FdRfcqp
 4RuEMe9faAadlXLsj3bia5IBmF/W0Qza6JilP+NLKLWB4fm7LZDjN/k+TsHWMa9e
 cGR73TgUGLMBJX+sDJy8R3oeBG9JZkFVkD7I30eCjzyhSOs/54XNYQ23EkqHJU0=
 =9Ryi
 -----END PGP SIGNATURE-----

Merge tag 'for-4.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - A major update for DM cache that reduces the latency for deciding
   whether blocks should migrate to/from the cache. The bio-prison-v2
   interface supports this improvement by enabling direct dispatch of
   work to workqueues rather than having to delay the actual work
   dispatch to the DM cache core. So the dm-cache policies are much more
   nimble by being able to drive IO as they see fit. One immediate
   benefit from the improved latency is a cache that should be much more
   adaptive to changing workloads.

 - Add a new DM integrity target that emulates a block device that has
   additional per-sector tags that can be used for storing integrity
   information.

 - Add a new authenticated encryption feature to the DM crypt target
   that builds on the capabilities provided by the DM integrity target.

 - Add MD interface for switching the raid4/5/6 journal mode and update
   the DM raid target to use it to enable aid4/5/6 journal write-back
   support.

 - Switch the DM verity target over to using the asynchronous hash
   crypto API (this helps work better with architectures that have
   access to off-CPU algorithm providers, which should reduce CPU
   utilization).

 - Various request-based DM and DM multipath fixes and improvements from
   Bart and Christoph.

 - A DM thinp target fix for a bio structure leak that occurs for each
   discard IFF discard passdown is enabled.

 - A fix for a possible deadlock in DM bufio and a fix to re-check the
   new buffer allocation watermark in the face of competing admin
   changes to the 'max_cache_size_bytes' tunable.

 - A couple DM core cleanups.

* tag 'for-4.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (50 commits)
  dm bufio: check new buffer allocation watermark every 30 seconds
  dm bufio: avoid a possible ABBA deadlock
  dm mpath: make it easier to detect unintended I/O request flushes
  dm mpath: cleanup QUEUE_IF_NO_PATH bit manipulation by introducing assign_bit()
  dm mpath: micro-optimize the hot path relative to MPATHF_QUEUE_IF_NO_PATH
  dm: introduce enum dm_queue_mode to cleanup related code
  dm mpath: verify __pg_init_all_paths locking assumptions at runtime
  dm: verify suspend_locking assumptions at runtime
  dm block manager: remove an unused argument from dm_block_manager_create()
  dm rq: check blk_mq_register_dev() return value in dm_mq_init_request_queue()
  dm mpath: delay requeuing while path initialization is in progress
  dm mpath: avoid that path removal can trigger an infinite loop
  dm mpath: split and rename activate_path() to prepare for its expanded use
  dm ioctl: prevent stack leak in dm ioctl call
  dm integrity: use previously calculated log2 of sectors_per_block
  dm integrity: use hex2bin instead of open-coded variant
  dm crypt: replace custom implementation of hex2bin()
  dm crypt: remove obsolete references to per-CPU state
  dm verity: switch to using asynchronous hash crypto API
  dm crypt: use WQ_HIGHPRI for the IO and crypt workqueues
  ...
2017-05-03 10:31:20 -07:00
Bart Van Assche 73cbca6a63 dm block manager: remove an unused argument from dm_block_manager_create()
The 'cache_size' argument of dm_block_manager_create() has never been
used.  Remove it along with the definitions of the constants passed as
the 'cache_size' argument.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-04-27 17:08:41 -04:00
Joe Thornber 0d963b6e65 dm cache metadata: fix metadata2 format's blocks_are_clean_separate_dirty
The dm_bitset_cursor_begin() call was using the incorrect nr_entries.
Also, the last dm_bitset_cursor_next() must be avoided if we're at the
end of the cursor.

Fixes: 7f1b21591a ("dm cache metadata: use cursor api in blocks_are_clean_separate_dirty()")
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-03-20 16:00:49 -04:00
Mike Snitzer 7f1b21591a dm cache metadata: use cursor api in blocks_are_clean_separate_dirty()
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-02-16 13:12:51 -05:00
Joe Thornber 683bb1a374 dm cache metadata: use dm_bitset_new() to create the dirty bitset in format 2
Big speed up with large configs.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-02-16 13:12:49 -05:00
Mike Snitzer 48551054fc dm cache metadata: name the cache block that couldn't be loaded
Improves __load_mapping_v1() and __load_mapping_v2() DMERR messages to
explicitly name the cache block number whose mapping couldn't be
loaded.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-02-16 13:12:48 -05:00
Joe Thornber 629d0a8a1a dm cache metadata: add "metadata2" feature
If "metadata2" is provided as a table argument when creating/loading a
cache target a more compact metadata format, with separate dirty bits,
is used.  "metadata2" improves speed of shutting down a cache target.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-02-16 13:12:47 -05:00
Joe Thornber ae4a46a1f6 dm cache metadata: use bitset cursor api to load discard bitset
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-02-16 13:12:46 -05:00
Mike Snitzer 07d938822a dm cache metadata: remove an extra newline in DMERR and code
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-11-21 09:52:02 -05:00
Joe Thornber f177940a80 dm cache metadata: switch to using the new cursor api for loading metadata
This change offers a pretty significant performance improvement.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-09-22 11:15:05 -04:00
Joe Thornber 4e781b498e dm cache: speed up writing of the hint array
It's far quicker to always delete the hint array and recreate with
dm_array_new() because we avoid the copying caused by mutation.

Also simplifies the policy interface, replacing the walk_hints() with
the simpler get_hint().

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-09-22 11:15:02 -04:00
Ahmed Samy 6545b60baa dm cache metadata: fix cmd_read_lock() acquiring write lock
Commit 9567366fef ("dm cache metadata: fix READ_LOCK macros and
cleanup WRITE_LOCK macros") uses down_write() instead of down_read() in
cmd_read_lock(), yet up_read() is used to release the lock in
READ_UNLOCK().  Fix it.

Fixes: 9567366fef ("dm cache metadata: fix READ_LOCK macros and cleanup WRITE_LOCK macros")
Cc: stable@vger.kernel.org
Signed-off-by: Ahmed Samy <f.fallen45@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-04-17 11:24:46 -04:00
Mike Snitzer 9567366fef dm cache metadata: fix READ_LOCK macros and cleanup WRITE_LOCK macros
The READ_LOCK macro was incorrectly returning -EINVAL if
dm_bm_is_read_only() was true -- it will always be true once the cache
metadata transitions to read-only by dm_cache_metadata_set_read_only().

Wrap READ_LOCK and WRITE_LOCK multi-statement macros in do {} while(0).
Also, all accesses of the 'cmd' argument passed to these related macros
are now encapsulated in parenthesis.

A follow-up patch can be developed to eliminate the use of macros in
favor of pure C code.  Avoiding that now given that this needs to apply
to stable@.

Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Fixes: d14fcf3dd7 ("dm cache: make sure every metadata function checks fail_io")
Cc: stable@vger.kernel.org
2016-04-14 17:34:49 -04:00
Joe Thornber d14fcf3dd7 dm cache: make sure every metadata function checks fail_io
Otherwise operations may be attempted that will only ever go on to crash
(since the metadata device is either missing or unreliable if 'fail_io'
is set).

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2016-03-10 17:12:12 -05:00
Linus Torvalds e0700ce709 - Revert a dm-multipath change that caused a regression for unprivledged
users (e.g. kvm guests) that issued ioctls when a multipath device had
   no available paths.
 
 - Include Christoph's refactoring of DM's ioctl handling and add support
   for passing through persistent reservations with DM multipath.
 
 - All other changes are very simple cleanups.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQEcBAABAgAGBQJWOp04AAoJEMUj8QotnQNaFLsH/AhMEH/jI1ObOfy4J1Wy4rOx
 ujJT91uS/s0H3pc9cGKQYnuGpFkX6WWU4wMiabIyiTn4sAsoXaflfIGutivLiDJr
 HfecrMrGZgnP4ZlpPPB02BmlxFbcPW8yzAU4ma38xBgQ+Pu30RO/HkvX/2vKOppG
 qwPop/XsNxq3KXgFGM44ToytM6c/MPGluhuvOwbaacAO1HviMuen9qsVjk4kwcf3
 jGYTbEPHATxyu5/6oKDTkQTYhzdwg3B2qHCiKMGw3l1kXhaQLFcaOivOLV8Sf3xh
 bj1070pkGe9OpqaVzMnwDtJ8rnsBl/Nt4wj9oiQPxbX71GYZAmcMIYn9WEkcKFI=
 =AR2D
 -----END PGP SIGNATURE-----

Merge tag 'dm-4.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:
 "Smaller set of DM changes for this merge.  I've based these changes on
  Jens' for-4.4/reservations branch because the associated DM changes
  required it.

   - Revert a dm-multipath change that caused a regression for
     unprivledged users (e.g. kvm guests) that issued ioctls when a
     multipath device had no available paths.

   - Include Christoph's refactoring of DM's ioctl handling and add
     support for passing through persistent reservations with DM
     multipath.

   - All other changes are very simple cleanups"

* tag 'dm-4.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm switch: simplify conditional in alloc_region_table()
  dm delay: document that offsets are specified in sectors
  dm delay: capitalize the start of an delay_ctr() error message
  dm delay: Use DM_MAPIO macros instead of open-coded equivalents
  dm linear: remove redundant target name from error messages
  dm persistent data: eliminate unnecessary return values
  dm: eliminate unused "bioset" process for each bio-based DM device
  dm: convert ffs to __ffs
  dm: drop NULL test before kmem_cache_destroy() and mempool_destroy()
  dm: add support for passing through persistent reservations
  dm: refactor ioctl handling
  Revert "dm mpath: fix stalls when handling invalid ioctls"
  dm: initialize non-blk-mq queue data before queue is used
2015-11-04 21:19:53 -08:00
Mikulas Patocka 4c7da06f5a dm persistent data: eliminate unnecessary return values
dm_bm_unlock and dm_tm_unlock return an integer value but the returned
value is always 0.  The calling code sometimes checks the return value
and sometimes doesn't.

Eliminate these unnecessary return values and also the checks for them.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:02 -04:00
Joe Thornber 3201ac452e dm cache: the CLEAN_SHUTDOWN flag was not being set
If the CLEAN_SHUTDOWN flag is not set when a cache is loaded then all cache
blocks are marked as dirty and a full writeback occurs.

__commit_transaction() is responsible for setting/clearing
CLEAN_SHUTDOWN (based the flags_mutator that is passed in).

Fix this issue, of the cache's on-disk flags being wrong, by making sure
__commit_transaction() does not reset the flags after the mutator has
altered the flags in preparation for them being serialized to disk.

before:

sb_flags = mutator(le32_to_cpu(disk_super->flags));
disk_super->flags = cpu_to_le32(sb_flags);
disk_super->flags = cpu_to_le32(cmd->flags);

after:

disk_super->flags = cpu_to_le32(cmd->flags);
sb_flags = mutator(le32_to_cpu(disk_super->flags));
disk_super->flags = cpu_to_le32(sb_flags);

Reported-by: Bogdan Vasiliev <bogdan.vasiliev@gmail.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-10-23 14:02:56 -04:00
Joe Thornber 028ae9f76f dm cache: add fail io mode and needs_check flag
If a cache metadata operation fails (e.g. transaction commit) the
cache's metadata device will abort the current transaction, set a new
needs_check flag, and the cache will transition to "read-only" mode.  If
aborting the transaction or setting the needs_check flag fails the cache
will transition to "fail-io" mode.

Once needs_check is set the cache device will not be allowed to
activate.  Activation requires write access to metadata.  Future work is
needed to add proper support for running the cache in read-only mode.

Once in fail-io mode the cache will report a status of "Fail".

Also, add commit() wrapper that will disallow commits if in read_only or
fail mode.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-06-11 17:13:00 -04:00
Joe Thornber 766a78882d dm cache: fix missing ERR_PTR returns and handling
Commit 9b1cc9f251 ("dm cache: share cache-metadata object across
inactive and active DM tables") mistakenly ignored the use of ERR_PTR
returns.  Restore missing IS_ERR checks and ERR_PTR returns where
appropriate.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-01-28 09:59:20 -05:00
Joe Thornber 9b1cc9f251 dm cache: share cache-metadata object across inactive and active DM tables
If a DM table is reloaded with an inactive table when the device is not
suspended (normal procedure for LVM2), then there will be two dm-bufio
objects that can diverge.  This can lead to a situation where the
inactive table uses bufio to read metadata at the same time the active
table writes metadata -- resulting in the inactive table having stale
metadata buffers once it is promoted to the active table slot.

Fix this by using reference counting and a global list of cache metadata
objects to ensure there is only one metadata object per metadata device.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-01-23 10:57:15 -05:00
Joe Thornber 1bad9bc4ee dm cache: revert "remove remainder of distinct discard block size"
This reverts commit 64ab346a36 because we
actually do want to allow the discard blocksize to be larger than the
cache blocksize.  Further dm-cache discard changes will make this
possible.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:30 -05:00
Mike Snitzer 895b47d798 dm cache metadata: use dm-space-map-metadata.h defined size limits
Commit 7d48935e cleaned up the persistent-data's space-map-metadata
limits by elevating them to dm-space-map-metadata.h.  Update
dm-cache-metadata to use these same limits.

The calculation for DM_CACHE_METADATA_MAX_SECTORS didn't account for the
sizeof the disk_bitmap_header.  So the supported maximum metadata size
is a bit smaller (reduced from 33423360 to 33292800 sectors).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2014-08-01 12:30:33 -04:00
Mike Snitzer 048e5a07f2 dm cache metadata: do not allow the data block size to change
The block size for the dm-cache's data device must remained fixed for
the life of the cache.  Disallow any attempt to change the cache's data
block size.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Cc: stable@vger.kernel.org
2014-07-15 14:07:50 -04:00
Joe Thornber 0596661f0a dm cache: fix a lock-inversion
When suspending a cache the policy is walked and the individual policy
hints written to the metadata via sync_metadata().  This led to this
lock order:

      policy->lock
        cache_metadata->root_lock

When loading the cache target the policy is populated while the metadata
lock is held:

      cache_metadata->root_lock
         policy->lock

Fix this potential lock-inversion (ABBA) deadlock in sync_metadata() by
ensuring the cache_metadata root_lock is held whilst all the hints are
written, rather than being repeatedly locked while policy->lock is held
(as was the case with each callout that policy_walk_mappings() made to
the old save_hint() method).

Found by turning on the CONFIG_PROVE_LOCKING ("Lock debugging: prove
locking correctness") build option.  However, it is not clear how the
LOCKDEP reported paths can lead to a deadlock since the two paths,
suspending a target and loading a target, never occur at the same time.
But that doesn't mean the same lock-inversion couldn't have occurred
elsewhere.

Reported-by: Marian Csontos <mcsontos@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-04-04 14:53:05 -04:00
Joe Thornber 5a32083d03 dm: take care to copy the space map roots before locking the superblock
In theory copying the space map root can fail, but in practice it never
does because we're careful to check what size buffer is needed.

But make certain we're able to copy the space map roots before
locking the superblock.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # drop dm-era and dm-cache changes as needed
2014-03-27 16:56:23 -04:00
Joe Thornber a9d45396f5 dm transaction manager: fix corruption due to non-atomic transaction commit
The persistent-data library used by dm-thin, dm-cache, etc is
transactional.  If anything goes wrong, such as an io error when writing
new metadata or a power failure, then we roll back to the last
transaction.

Atomicity when committing a transaction is achieved by:

a) Never overwriting data from the previous transaction.
b) Writing the superblock last, after all other metadata has hit the
   disk.

This commit and the following commit ("dm: take care to copy the space
map roots before locking the superblock") fix a bug associated with (b).
When committing it was possible for the superblock to still be written
in spite of an io error occurring during the preceeding metadata flush.
With these commits we're careful not to take the write lock out on the
superblock until after the metadata flush has completed.

Change the transaction manager's semantics for dm_tm_commit() to assume
all data has been flushed _before_ the single superblock that is passed
in.

As a prerequisite, split the block manager's block unlocking and
flushing by simplifying dm_bm_flush_and_unlock() to dm_bm_flush().  Now
the unlocking must be done separately.

This issue was discovered by forcing io errors at the crucial time
using dm-flakey.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-03-27 16:56:23 -04:00
Heinz Mauelshagen 64ab346a36 dm cache: remove remainder of distinct discard block size
Discard block size not being equal to cache block size causes data
corruption by erroneously avoiding migrations in issue_copy() because
the discard state is being cleared for a group of cache blocks when it
should not.

Completely remove all code that enabled a distinction between the
cache block size and discard block size.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-27 16:56:23 -04:00
Joe Thornber 53d498198d dm cache metadata: check the metadata version when reading the superblock
Need to check the version to verify on-disk metadata is supported.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-11 11:37:49 -05:00
Joe Thornber 2ee57d5873 dm cache: add passthrough mode
"Passthrough" is a dm-cache operating mode (like writethrough or
writeback) which is intended to be used when the cache contents are not
known to be coherent with the origin device.  It behaves as follows:

* All reads are served from the origin device (all reads miss the cache)
* All writes are forwarded to the origin device; additionally, write
  hits cause cache block invalidates

This mode decouples cache coherency checks from cache device creation,
largely to avoid having to perform coherency checks while booting.  Boot
scripts can create cache devices in passthrough mode and put them into
service (mount cached filesystems, for example) without having to worry
about coherency.  Coherency that exists is maintained, although the
cache will gradually cool as writes take place.

Later, applications can perform coherency checks, the nature of which
will depend on the type of the underlying storage.  If coherency can be
verified, the cache device can be transitioned to writethrough or
writeback mode while still warm; otherwise, the cache contents can be
discarded prior to transitioning to the desired operating mode.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-11 11:37:49 -05:00
Joe Thornber f494a9c6b1 dm cache: cache shrinking support
Allow a cache to shrink if the blocks being removed from the cache are
not dirty.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-11 11:37:45 -05:00
Joe Thornber dd8b0c2096 dm cache metadata: return bool from __superblock_all_zeroes
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-09 18:20:17 -05:00