kernel/git/stable/linux-stable.git/drivers/md/md.c, branch linux-6.10.y

md: Don't flush sync_work in md_write_start()

2024-10-04T14:33:41+00:00

commit 86ad4cda79e0dade87d4bb0d32e1fe541d4a63e8 upstream. Because flush sync_work may trigger mddev_suspend() if there are spares, and this should never be done in IO path because mddev_suspend() is used to wait for IO. This problem is found by code review. Fixes: bc08041b32ab ("md: suspend array in md_start_sync() if array need reconfiguration") Cc: stable@vger.kernel.org Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20240801124746.242558-1-yukuai1@huaweicloud.com Signed-off-by: Song Liu Signed-off-by: Greg Kroah-Hartman

md: change the return value type of md_write_start to void

2024-08-14T13:34:06+00:00

[ Upstream commit 03e792eaf18ec2e93e2c623f9f1a4bdb97fe4126 ] Commit cc27b0c78c79 ("md: fix deadlock between mddev_suspend() and md_write_start()") aborted md_write_start() with false when mddev is suspended, which fixed a deadlock if calling mddev_suspend() with holding reconfig_mutex(). Since mddev_suspend() now includes lockdep_assert_not_held(), it no longer holds the reconfig_mutex. This makes previous abort unnecessary. Now, remove unnecessary abort and change function return value to void. Signed-off-by: Li Nan Reviewed-by: Yu Kuai Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20240525185257.3896201-2-linan666@huaweicloud.com Signed-off-by: Sasha Levin

md: do not delete safemode_timer in mddev_suspend

2024-08-14T13:34:06+00:00

[ Upstream commit a8768a134518e406d41799a3594aeb74e0889cf7 ] The deletion of safemode_timer in mddev_suspend() is redundant and potentially harmful now. If timer is about to be woken up but gets deleted, 'in_sync' will remain 0 until the next write, causing array to stay in the 'active' state instead of transitioning to 'clean'. Commit 0d9f4f135eb6 ("MD: Add del_timer_sync to mddev_suspend (fix nasty panic))" introduced this deletion for dm, because if timer fired after dm is destroyed, the resource which the timer depends on might have been freed. However, commit 0dd84b319352 ("md: call __md_stop_writes in md_stop") added __md_stop_writes() to md_stop(), which is called before freeing resource. Timer is deleted in __md_stop_writes(), and the origin issue is resolved. Therefore, delete safemode_timer can be removed safely now. Signed-off-by: Li Nan Reviewed-by: Yu Kuai Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20240508092053.1447930-1-linan666@huaweicloud.com Signed-off-by: Sasha Levin

md: Don't wait for MD_RECOVERY_NEEDED for HOT_REMOVE_DISK ioctl

2024-08-03T06:59:13+00:00

[ Upstream commit a1fd37f97808db4fa1bf55da0275790c42521e45 ] Commit 90f5f7ad4f38 ("md: Wait for md_check_recovery before attempting device removal.") explained in the commit message that failed device must be reomoved from the personality first by md_check_recovery(), before it can be removed from the array. That's the reason the commit add the code to wait for MD_RECOVERY_NEEDED. However, this is not the case now, because remove_and_add_spares() is called directly from hot_remove_disk() from ioctl path, hence failed device(marked faulty) can be removed from the personality by ioctl. On the other hand, the commit introduced a performance problem that if MD_RECOVERY_NEEDED is set and the array is not running, ioctl will wait for 5s before it can return failure to user. Since the waiting is not needed now, fix the problem by removing the waiting. Fixes: 90f5f7ad4f38 ("md: Wait for md_check_recovery before attempting device removal.") Reported-by: Mateusz Kusiak Closes: https://lore.kernel.org/all/814ff6ee-47a2-4ba0-963e-cf256ee4ecfa@linux.intel.com/ Signed-off-by: Yu Kuai Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20240627112321.3044744-1-yukuai1@huaweicloud.com Signed-off-by: Sasha Levin

md: fix deadlock between mddev_suspend and flush bio

2024-08-03T06:59:10+00:00

[ Upstream commit 611d5cbc0b35a752e657a83eebadf40d814d006b ] Deadlock occurs when mddev is being suspended while some flush bio is in progress. It is a complex issue. T1. the first flush is at the ending stage, it clears 'mddev->flush_bio' and tries to submit data, but is blocked because mddev is suspended by T4. T2. the second flush sets 'mddev->flush_bio', and attempts to queue md_submit_flush_data(), which is already running (T1) and won't execute again if on the same CPU as T1. T3. the third flush inc active_io and tries to flush, but is blocked because 'mddev->flush_bio' is not NULL (set by T2). T4. mddev_suspend() is called and waits for active_io dec to 0 which is inc by T3. T1 T2 T3 T4 (flush 1) (flush 2) (third 3) (suspend) md_submit_flush_data mddev->flush_bio = NULL; . . md_flush_request . mddev->flush_bio = bio . queue submit_flushes . . . . md_handle_request . . active_io + 1 . . md_flush_request . . wait !mddev->flush_bio . . . . mddev_suspend . . wait !active_io . . . submit_flushes . queue_work md_submit_flush_data . //md_submit_flush_data is already running (T1) . md_handle_request wait resume The root issue is non-atomic inc/dec of active_io during flush process. active_io is dec before md_submit_flush_data is queued, and inc soon after md_submit_flush_data() run. md_flush_request active_io + 1 submit_flushes active_io - 1 md_submit_flush_data md_handle_request active_io + 1 make_request active_io - 1 If active_io is dec after md_handle_request() instead of within submit_flushes(), make_request() can be called directly intead of md_handle_request() in md_submit_flush_data(), and active_io will only inc and dec once in the whole flush process. Deadlock will be fixed. Additionally, the only difference between fixing the issue and before is that there is no return error handling of make_request(). But after previous patch cleaned md_write_start(), make_requst() only return error in raid5_make_request() by dm-raid, see commit 41425f96d7aa ("dm-raid456, md/raid456: fix a deadlock for dm-raid456 while io concurrent with reshape)". Since dm always splits data and flush operation into two separate io, io size of flush submitted by dm always is 0, make_request() will not be called in md_submit_flush_data(). To prevent future modifications from introducing issues, add WARN_ON to ensure make_request() no error is returned in this context. Fixes: fa2bbff7b0b4 ("md: synchronize flush io with array reconfiguration") Signed-off-by: Li Nan Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20240525185257.3896201-3-linan666@huaweicloud.com Signed-off-by: Sasha Levin

md: Revert "md: Fix overflow in is_mddev_idle"

2024-05-07T13:34:08+00:00

This reverts commit 3f9f231236ce7e48780d8a4f1f8cb9fae2df1e4e. Using 64bit for 'sync_io' is unnecessary from the gendisk side. This overflow will not cause any functional impact, except for a UBSAN warning. Solving this overflow requires introducing additional calculations and checks which are not necessary. So just keep using 32bit for 'sync_io'. Signed-off-by: Li Nan Link: https://lore.kernel.org/r/20240507023103.781816-1-linan666@huaweicloud.com Signed-off-by: Jens Axboe

md: don't account sync_io if iostats of the disk is disabled

2024-04-09T04:15:46+00:00

If iostats is disabled, disk_stats will not be updated and part_stat_read_accum() only returns a constant value. In this case, continuing to count sync_io and to check is_mddev_idle() is no longer meaningful. Signed-off-by: Li Nan Reviewed-by: Yu Kuai Link: https://lore.kernel.org/r/20240117031946.2324519-3-linan666@huaweicloud.com Signed-off-by: Song Liu

md: Fix overflow in is_mddev_idle

2024-04-09T04:15:46+00:00

UBSAN reports this problem: UBSAN: Undefined behaviour in drivers/md/md.c:8175:15 signed integer overflow: -2147483291 - 2072033152 cannot be represented in type 'int' Call trace: dump_backtrace+0x0/0x310 show_stack+0x28/0x38 dump_stack+0xec/0x15c ubsan_epilogue+0x18/0x84 handle_overflow+0x14c/0x19c __ubsan_handle_sub_overflow+0x34/0x44 is_mddev_idle+0x338/0x3d8 md_do_sync+0x1bb8/0x1cf8 md_thread+0x220/0x288 kthread+0x1d8/0x1e0 ret_from_fork+0x10/0x18 'curr_events' will overflow when stat accum or 'sync_io' is greater than INT_MAX. Fix it by changing sync_io, last_events and curr_events to 64bit. Signed-off-by: Li Nan Reviewed-by: Yu Kuai Link: https://lore.kernel.org/r/20240117031946.2324519-2-linan666@huaweicloud.com Signed-off-by: Song Liu

md: add check for sleepers in md_wakeup_thread()

2024-04-09T04:14:37+00:00

Check for sleeping thread before attempting its wake_up in md_wakeup_thread() to avoid unnecessary spinlock contention. With a 6.1 kernel, fio random read/write tests on many (>= 100) virtual volumes, of 100 GiB each, on 3 md-raid5s on 8 SSDs each (building a raid50), show by 3 to 4 % improved IOPS performance. Signed-off-by: Florian-Ewald Mueller Reviewed-by: Yu Kuai Signed-off-by: Jack Wang Link: https://lore.kernel.org/r/20240327114022.74634-1-jinpu.wang@ionos.com Signed-off-by: Song Liu

Merge tag 'for-6.9/block-20240310' of git://git.kernel.dk/linux

2024-03-11T18:43:44+00:00

Pull block updates from Jens Axboe: - MD pull requests via Song: - Cleanup redundant checks (Yu Kuai) - Remove deprecated headers (Marc Zyngier, Song Liu) - Concurrency fixes (Li Lingfeng) - Memory leak fix (Li Nan) - Refactor raid1 read_balance (Yu Kuai, Paul Luse) - Clean up and fix for md_ioctl (Li Nan) - Other small fixes (Gui-Dong Han, Heming Zhao) - MD atomic limits (Christoph) - NVMe pull request via Keith: - RDMA target enhancements (Max) - Fabrics fixes (Max, Guixin, Hannes) - Atomic queue_limits usage (Christoph) - Const use for class_register (Ricardo) - Identification error handling fixes (Shin'ichiro, Keith) - Improvement and cleanup for cached request handling (Christoph) - Moving towards atomic queue limits. Core changes and driver bits so far (Christoph) - Fix UAF issues in aoeblk (Chun-Yi) - Zoned fix and cleanups (Damien) - s390 dasd cleanups and fixes (Jan, Miroslav) - Block issue timestamp caching (me) - noio scope guarding for zoned IO (Johannes) - block/nvme PI improvements (Kanchan) - Ability to terminate long running discard loop (Keith) - bdev revalidation fix (Li) - Get rid of old nr_queues hack for kdump kernels (Ming) - Support for async deletion of ublk (Ming) - Improve IRQ bio recycling (Pavel) - Factor in CPU capacity for remote vs local completion (Qais) - Add shared_tags configfs entry for null_blk (Shin'ichiro - Fix for a regression in page refcounts introduced by the folio unification (Tony) - Misc fixes and cleanups (Arnd, Colin, John, Kunwu, Li, Navid, Ricardo, Roman, Tang, Uwe) * tag 'for-6.9/block-20240310' of git://git.kernel.dk/linux: (221 commits) block: partitions: only define function mac_fix_string for CONFIG_PPC_PMAC block/swim: Convert to platform remove callback returning void cdrom: gdrom: Convert to platform remove callback returning void block: remove disk_stack_limits md: remove mddev->queue md: don't initialize queue limits md/raid10: use the atomic queue limit update APIs md/raid5: use the atomic queue limit update APIs md/raid1: use the atomic queue limit update APIs md/raid0: use the atomic queue limit update APIs md: add queue limit helpers md: add a mddev_is_dm helper md: add a mddev_add_trace_msg helper md: add a mddev_trace_remap helper bcache: move calculation of stripe_size and io_opt into bcache_device_init virtio_blk: Do not use disk_set_max_open/active_zones() aoe: fix the potential use-after-free problem in aoecmd_cfg_pkts block: move capacity validation to blkpg_do_ioctl() block: prevent division by zero in blk_rq_stat_sum() drbd: atomically update queue limits in drbd_reconsider_queue_parameters ...