WSL2-Linux-Kernel/drivers/md
Alex Wu ee37d7314a md/raid10: Fix raid10 replace hang when new added disk faulty
[Symptom]

Resync thread hang when new added disk faulty during replacing.

[Root Cause]

In raid10_sync_request(), we expect to issue a bio with callback
end_sync_read(), and a bio with callback end_sync_write().

In normal situation, we will add resyncing sectors into
mddev->recovery_active when raid10_sync_request() returned, and sub
resynced sectors from mddev->recovery_active when end_sync_write()
calls end_sync_request().

If new added disk, which are replacing the old disk, is set faulty,
there is a race condition:
    1. In the first rcu protected section, resync thread did not detect
       that mreplace is set faulty and pass the condition.
    2. In the second rcu protected section, mreplace is set faulty.
    3. But, resync thread will prepare the read object first, and then
       check the write condition.
    4. It will find that mreplace is set faulty and do not have to
       prepare write object.
This cause we add resync sectors but never sub it.

[How to Reproduce]

This issue can be easily reproduced by the following steps:
    mdadm -C /dev/md0 --assume-clean -l 10 -n 4 /dev/sd[abcd]
    mdadm /dev/md0 -a /dev/sde
    mdadm /dev/md0 --replace /dev/sdd
    sleep 1
    mdadm /dev/md0 -f /dev/sde

[How to Fix]

This issue can be fixed by using local variables to record the result
of test conditions. Once the conditions are satisfied, we can make sure
that we need to issue a bio for read and a bio for write.

Previous 'commit 24afd80d99 ("md/raid10: handle recovery of
replacement devices.")' will also check whether bio is NULL, but leave
the comment saying that it is a pointless test. So we remove this dummy
check.

Reported-by: Alex Chen <alexchen@synology.com>
Reviewed-by: Allen Peng <allenpeng@synology.com>
Reviewed-by: BingJing Chang <bingjingc@synology.com>
Signed-off-by: Alex Wu <alexwu@synology.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2018-09-28 11:42:47 -07:00
..
bcache bcache: release dc->writeback_lock properly in bch_writeback_thread() 2018-08-22 15:06:29 -06:00
persistent-data dm: Avoid namespace collision with bitmap API 2018-08-01 15:49:38 -07:00
Kconfig dm: add writecache target 2018-06-08 11:59:51 -04:00
Makefile dm: add writecache target 2018-06-08 11:59:51 -04:00
dm-bio-prison-v1.c dm: adjust structure members to improve alignment 2018-06-08 11:53:14 -04:00
dm-bio-prison-v1.h block: switch bios to blk_status_t 2017-06-09 09:27:32 -06:00
dm-bio-prison-v2.c dm: adjust structure members to improve alignment 2018-06-08 11:53:14 -04:00
dm-bio-prison-v2.h dm bio prison v2: new interface for the bio prison 2017-03-07 11:30:16 -05:00
dm-bio-record.h block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
dm-bufio.c dm bufio: fix buffer alignment 2018-04-30 11:51:39 -04:00
dm-builtin.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dm-cache-background-tracker.c dm cache background tracker: fix sparse warning 2018-04-30 15:40:40 -04:00
dm-cache-background-tracker.h dm cache: significant rework to leverage dm-bio-prison-v2 2017-03-07 13:28:31 -05:00
dm-cache-block-types.h linux: drop __bitwise__ everywhere 2016-12-16 00:13:41 +02:00
dm-cache-metadata.c dm cache metadata: set dirty on all cache blocks after a crash 2018-08-09 12:14:32 -04:00
dm-cache-metadata.h dm cache: significant rework to leverage dm-bio-prison-v2 2017-03-07 13:28:31 -05:00
dm-cache-policy-internal.h dm cache: significant rework to leverage dm-bio-prison-v2 2017-03-07 13:28:31 -05:00
dm-cache-policy-smq.c treewide: Use array_size() in vzalloc() 2018-06-12 16:19:22 -07:00
dm-cache-policy.c
dm-cache-policy.h dm cache: significant rework to leverage dm-bio-prison-v2 2017-03-07 13:28:31 -05:00
dm-cache-target.c dm kcopyd: return void from dm_kcopyd_copy() 2018-07-31 17:33:21 -04:00
dm-core.h dm: adjust structure members to improve alignment 2018-06-08 11:53:14 -04:00
dm-crypt.c dm: disable CRYPTO_TFM_REQ_MAY_SLEEP to fix a GFP_KERNEL recursion deadlock 2018-09-06 13:31:09 -04:00
dm-delay.c dm delay: add flush as a third class of IO 2018-07-27 15:24:19 -04:00
dm-era-target.c dm: allow targets to return output from messages they are sent 2018-04-03 15:04:10 -04:00
dm-exception-store.c
dm-exception-store.h
dm-flakey.c dm: remove fmode_t argument from .prepare_ioctl hook 2018-04-04 12:12:39 -04:00
dm-integrity.c dm: disable CRYPTO_TFM_REQ_MAY_SLEEP to fix a GFP_KERNEL recursion deadlock 2018-09-06 13:31:09 -04:00
dm-io.c dm: Use kzalloc for all structs with embedded biosets/mempools 2018-06-05 08:47:43 -06:00
dm-ioctl.c dm: report which conflicting type caused error during table_load() 2018-06-08 09:50:15 -04:00
dm-kcopyd.c dm kcopyd: avoid softlockup in run_complete_job 2018-08-08 09:16:24 -04:00
dm-linear.c dax: Introduce a ->copy_to_iter dax operation 2018-05-22 23:18:31 -07:00
dm-log-userspace-base.c dm: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
dm-log-userspace-transfer.c
dm-log-userspace-transfer.h
dm-log-writes.c dax: Introduce a ->copy_to_iter dax operation 2018-05-22 23:18:31 -07:00
dm-log.c block,fs: use REQ_* flags directly 2016-11-01 09:43:26 -06:00
dm-mpath.c block: sanitize blk_get_request calling conventions 2018-05-14 08:55:12 -06:00
dm-mpath.h
dm-path-selector.c
dm-path-selector.h
dm-queue-length.c dm mpath selector: more evenly distribute ties 2018-01-29 13:44:58 -05:00
dm-raid.c dm raid: bump target version, update comments and documentation 2018-09-06 17:07:58 -04:00
dm-raid1.c dm kcopyd: return void from dm_kcopyd_copy() 2018-07-31 17:33:21 -04:00
dm-region-hash.c - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
dm-round-robin.c dm round robin: revert "use percpu 'repeat_count' and 'current_path'" 2017-02-17 00:54:09 -05:00
dm-rq.c dm: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
dm-rq.h dm rq: do not update rq partially in each ending bio 2017-08-28 10:23:28 -04:00
dm-service-time.c dm mpath selector: more evenly distribute ties 2018-01-29 13:44:58 -05:00
dm-snap-persistent.c dm bufio: move dm-bufio.h to include/linux/ 2018-04-03 15:04:23 -04:00
dm-snap-transient.c
dm-snap.c dm snapshot: remove stale FIXME in snapshot_map() 2018-08-08 20:50:58 -04:00
dm-stats.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
dm-stats.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dm-stripe.c dax: Introduce a ->copy_to_iter dax operation 2018-05-22 23:18:31 -07:00
dm-switch.c treewide: Use array_size() in vmalloc() 2018-06-12 16:19:22 -07:00
dm-sysfs.c dm: move request-based code out to dm-rq.[hc] 2016-06-10 15:15:44 -04:00
dm-table.c dm: prevent DAX mounts if not supported 2018-06-28 16:06:14 -04:00
dm-target.c dm: remove unused macro DM_MOD_NAME_SIZE 2018-04-03 15:04:15 -04:00
dm-thin-metadata.c dm thin metadata: try to avoid ever aborting transactions 2018-09-10 17:03:18 -04:00
dm-thin-metadata.h dm thin: fix a race condition between discarding and provisioning a block 2016-07-20 12:43:35 -04:00
dm-thin.c dm thin metadata: try to avoid ever aborting transactions 2018-09-10 17:03:18 -04:00
dm-uevent.c
dm-uevent.h
dm-unstripe.c dm unstripe: remove unnecessary header includes 2018-04-03 15:04:15 -04:00
dm-verity-fec.c Refactors rslib and callers to provide a per-instance allocation area 2018-06-05 10:48:05 -07:00
dm-verity-fec.h dm: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
dm-verity-target.c dm verity: fix crash on bufio buffer that was allocated with vmalloc 2018-09-04 11:25:25 -04:00
dm-verity.h dm verity: add 'check_at_most_once' option to only validate hashes once 2018-04-03 15:04:29 -04:00
dm-writecache.c libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
dm-zero.c dm: don't return errnos from ->map 2017-06-09 09:27:32 -06:00
dm-zoned-metadata.c dm: backfill missing calls to mutex_destroy() 2018-01-17 09:16:15 -05:00
dm-zoned-reclaim.c dm kcopyd: return void from dm_kcopyd_copy() 2018-07-31 17:33:21 -04:00
dm-zoned-target.c dm zoned: avoid triggering reclaim from inside dmz_map() 2018-06-22 14:51:12 -04:00
dm-zoned.h dm zoned: drive-managed zoned block device target 2017-06-19 11:05:20 -04:00
dm.c block: Add and use op_stat_group() for indexing disk_stat fields. 2018-07-18 08:44:20 -06:00
dm.h dm: move dm_table_destroy() to same header as dm_table_create() 2018-01-17 09:16:06 -05:00
md-bitmap.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2018-08-18 16:48:07 -07:00
md-bitmap.h md: Avoid namespace collision with bitmap API 2018-08-01 15:49:39 -07:00
md-cluster.c md-cluster: release RESYNC lock after the last resync message 2018-08-31 17:38:10 -07:00
md-cluster.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
md-faulty.c md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
md-linear.c md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
md-linear.h Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-11-14 16:07:26 -08:00
md-multipath.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
md-multipath.h md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
md.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2018-08-18 16:48:07 -07:00
md.h md-cluster: show array's status more accurate 2018-07-05 11:17:01 -07:00
raid0.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
raid0.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
raid1-10.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
raid1.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2018-08-18 16:48:07 -07:00
raid1.h md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
raid5-cache.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2018-08-18 16:48:07 -07:00
raid5-log.h md/raid5-cache: disable reshape completely 2018-08-31 17:38:09 -07:00
raid5-ppl.c md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
raid5.c raid5: block failing device if raid will be failed 2018-09-28 11:13:15 -07:00
raid5.h Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2018-06-09 12:01:36 -07:00
raid10.c md/raid10: Fix raid10 replace hang when new added disk faulty 2018-09-28 11:42:47 -07:00
raid10.h md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00