kernel/drivers/md/dm.c, branch linux-6.3.y

dm: don't lock fs when the map is NULL during suspend or resume

2023-06-21T14:02:18Z

[ Upstream commit 2760904d895279f87196f0fa9ec570c79fe6a2e4 ] As described in commit 38d11da522aa ("dm: don't lock fs when the map is NULL in process of resume"), a deadlock may be triggered between do_resume() and do_mount(). This commit preserves the fix from commit 38d11da522aa but moves it to where it also serves to fix a similar deadlock between do_suspend() and do_mount(). It does so, if the active map is NULL, by clearing DM_SUSPEND_LOCKFS_FLAG in dm_suspend() which is called by both do_suspend() and do_resume(). Fixes: 38d11da522aa ("dm: don't lock fs when the map is NULL in process of resume") Signed-off-by: Li Lingfeng Signed-off-by: Mike Snitzer Signed-off-by: Sasha Levin

dm: fix __send_duplicate_bios() to always allow for splitting IO

2023-03-30T19:54:32Z

Commit 7dd76d1feec70 ("dm: improve bio splitting and associated IO accounting") only called setup_split_accounting() from __send_duplicate_bios() if a single bio were being issued. But the case where duplicate bios are issued must call it too. Otherwise the bio won't be split and resubmitted (via recursion through block core back to DM) to submit the later portions of a bio (which may map to an entirely different target). For example, when discarding an entire DM striped device with the following DM table: vg-lvol0: 0 159744 striped 2 128 7:0 2048 7:1 2048 vg-lvol0: 159744 45056 striped 2 128 7:2 2048 7:3 2048 Before (broken, discards the first striped target's devices twice): device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=79872 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=79872 device-mapper: striped: target_stripe=0, bdev=7:0, start=2049 len=22528 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=22528 After (works as expected): device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=79872 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=79872 device-mapper: striped: target_stripe=0, bdev=7:2, start=2048 len=22528 device-mapper: striped: target_stripe=1, bdev=7:3, start=2048 len=22528 Fixes: 7dd76d1feec70 ("dm: improve bio splitting and associated IO accounting") Cc: stable@vger.kernel.org Reported-by: Orange Kao Signed-off-by: Mike Snitzer

dm: fix improper splitting for abnormal bios

2023-03-30T19:54:32Z

"Abnormal" bios include discards, write zeroes and secure erase. By no longer passing the calculated 'len' pointer, commit 7dd06a2548b2 ("dm: allow dm_accept_partial_bio() for dm_io without duplicate bios") took a senseless approach to disallowing dm_accept_partial_bio() from working for duplicate bios processed using __send_duplicate_bios(). It inadvertently and incorrectly stopped the use of 'len' when initializing a target's io (in alloc_tio). As such the resulting tio could address more area of a device than it should. For example, when discarding an entire DM striped device with the following DM table: vg-lvol0: 0 159744 striped 2 128 7:0 2048 7:1 2048 vg-lvol0: 159744 45056 striped 2 128 7:2 2048 7:3 2048 Before this fix: device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=102400 blkdiscard: attempt to access beyond end of device loop0: rw=2051, sector=2048, nr_sectors = 102400 limit=81920 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=102400 blkdiscard: attempt to access beyond end of device loop1: rw=2051, sector=2048, nr_sectors = 102400 limit=81920 After this fix; device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=79872 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=79872 Fixes: 7dd06a2548b2 ("dm: allow dm_accept_partial_bio() for dm_io without duplicate bios") Cc: stable@vger.kernel.org Reported-by: Orange Kao Signed-off-by: Mike Snitzer

Merge tag 'for-6.3/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2023-03-24T21:20:48Z

Pull device mapper fixes from Mike Snitzer: - Fix DM thin to work as a swap device by using 'limit_swap_bios' DM target flag (initially added to allow swap to dm-crypt) to throttle the amount of outstanding swap bios. - Fix DM crypt soft lockup warnings by calling cond_resched() from the cpu intensive loop in dmcrypt_write(). - Fix DM crypt to not access an uninitialized tasklet. This fix allows for consistent handling of IO completion, by _not_ needlessly punting to a workqueue when tasklets are not needed. - Fix DM core's alloc_dev() initialization for DM stats to check for and propagate alloc_percpu() failure. * tag 'for-6.3/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm stats: check for and propagate alloc_percpu failure dm crypt: avoid accessing uninitialized tasklet dm crypt: add cond_resched() to dmcrypt_write() dm thin: fix deadlock when swapping to thin device

dm stats: check for and propagate alloc_percpu failure

2023-03-16T17:37:06Z

Check alloc_precpu()'s return value and return an error from dm_stats_init() if it fails. Update alloc_dev() to fail if dm_stats_init() does. Otherwise, a NULL pointer dereference will occur in dm_stats_cleanup() even if dm-stats isn't being actively used. Fixes: fd2ed4d25270 ("dm: add statistics support") Cc: stable@vger.kernel.org Signed-off-by: Jiasheng Jiang Signed-off-by: Mike Snitzer

block: count 'ios' and 'sectors' when io is done for bio-based device

2023-03-15T15:25:04Z

While using iostat for raid, I observed very strange 'await' occasionally, and turns out it's due to that 'ios' and 'sectors' is counted in bdev_start_io_acct(), while 'nsecs' is counted in bdev_end_io_acct(). I'm not sure why they are ccounted like that but I think this behaviour is obviously wrong because user will get wrong disk stats. Fix the problem by counting 'ios' and 'sectors' when io is done, like what rq-based device does. Fixes: 394ffa503bc4 ("blk: introduce generic io stat accounting help function") Signed-off-by: Yu Kuai Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20230223091226.1135678-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe

dm: remove unnecessary (void*) conversion in event_callback()

2023-02-20T16:52:49Z

Pointer variables of void * type do not require type cast. Signed-off-by: XU pengfei Signed-off-by: Mike Snitzer

dm: add cond_resched() to dm_wq_requeue_work()

2023-02-16T17:10:05Z

Otherwise the while() loop in dm_wq_requeue_work() can result in a "dead loop" on systems that have preemption disabled. This is particularly problematic on single cpu systems. Fixes: 8b211aaccb915 ("dm: add two stage requeue mechanism") Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer

dm: add cond_resched() to dm_wq_work()

2023-02-16T17:06:44Z

Otherwise the while() loop in dm_wq_work() can result in a "dead loop" on systems that have preemption disabled. This is particularly problematic on single cpu systems. Cc: stable@vger.kernel.org Signed-off-by: Pingfan Liu Acked-by: Ming Lei Signed-off-by: Mike Snitzer

dm: remove flush_scheduled_work() during local_exit()

2023-02-14T19:23:08Z

Commit acfe0ad74d2e1 ("dm: allocate a special workqueue for deferred device removal") switched from using system workqueue to a single workqueue local to DM. But it didn't eliminate the call to flush_scheduled_work() that was introduced purely for the benefit of deferred device removal with commit 2c140a246dc ("dm: allow remove to be deferred"). Since DM core uses its own workqueue (and queue_work) there is no need to call flush_scheduled_work() from local_exit(). local_exit()'s destroy_workqueue(deferred_remove_workqueue) handles flushing work started with queue_work(). Fixes: acfe0ad74d2e1 ("dm: allocate a special workqueue for deferred device removal") Signed-off-by: Mike Snitzer