diff options
author | Yu Kuai <yukuai3@huawei.com> | 2024-02-01 17:25:47 +0800 |
---|---|---|
committer | Song Liu <song@kernel.org> | 2024-02-15 14:17:13 -0800 |
commit | 55a48ad2db64737f7ffc0407634218cc6e4c513b (patch) | |
tree | aeb9ad88e8210442b0c0e2b5132e969cb8530a3a /drivers/md | |
parent | 1baae052cccd08daf9a9d64c3f959d8cdb689757 (diff) |
md: Don't ignore read-only array in md_check_recovery()
Usually if the array is not read-write, md_check_recovery() won't
register new sync_thread in the first place. And if the array is
read-write and sync_thread is registered, md_set_readonly() will
unregister sync_thread before setting the array read-only. md/raid
follow this behavior hence there is no problem.
After commit f52f5c71f3d4 ("md: fix stopping sync thread"), following
hang can be triggered by test shell/integrity-caching.sh:
1) array is read-only. dm-raid update super block:
rs_update_sbs
ro = mddev->ro
mddev->ro = 0
-> set array read-write
md_update_sb
2) register new sync thread concurrently.
3) dm-raid set array back to read-only:
rs_update_sbs
mddev->ro = ro
4) stop the array:
raid_dtr
md_stop
stop_sync_thread
set_bit(MD_RECOVERY_INTR, &mddev->recovery);
md_wakeup_thread_directly(mddev->sync_thread);
wait_event(..., !test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
5) sync thread done:
md_do_sync
set_bit(MD_RECOVERY_DONE, &mddev->recovery);
md_wakeup_thread(mddev->thread);
6) daemon thread can't unregister sync thread:
md_check_recovery
if (!md_is_rdwr(mddev) &&
!test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
return;
-> -> MD_RECOVERY_RUNNING can't be cleared, hence step 4 hang;
The root cause is that dm-raid manipulate 'mddev->ro' by itself,
however, dm-raid really should stop sync thread before setting the
array read-only. Unfortunately, I need to read more code before I
can refacter the handler of 'mddev->ro' in dm-raid, hence let's fix
the problem the easy way for now to prevent dm-raid regression.
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Closes: https://lore.kernel.org/all/9801e40-8ac7-e225-6a71-309dcf9dc9aa@redhat.com/
Fixes: ecbfb9f118bc ("dm raid: add raid level takeover support")
Fixes: f52f5c71f3d4 ("md: fix stopping sync thread")
Cc: stable@vger.kernel.org # v6.7+
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240201092559.910982-3-yukuai1@huaweicloud.com
Diffstat (limited to 'drivers/md')
-rw-r--r-- | drivers/md/md.c | 31 |
1 files changed, 18 insertions, 13 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index eea8dd529b5e..2a1c19f87d01 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9449,6 +9449,20 @@ not_running: sysfs_notify_dirent_safe(mddev->sysfs_action); } +static void unregister_sync_thread(struct mddev *mddev) +{ + if (!test_bit(MD_RECOVERY_DONE, &mddev->recovery)) { + /* resync/recovery still happening */ + clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + return; + } + + if (WARN_ON_ONCE(!mddev->sync_thread)) + return; + + md_reap_sync_thread(mddev); +} + /* * This routine is regularly called by all per-raid-array threads to * deal with generic issues like resync and super-block update. @@ -9486,7 +9500,8 @@ void md_check_recovery(struct mddev *mddev) } if (!md_is_rdwr(mddev) && - !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery)) + !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) && + !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) return; if ( ! ( (mddev->sb_flags & ~ (1<<MD_SB_CHANGE_PENDING)) || @@ -9508,8 +9523,7 @@ void md_check_recovery(struct mddev *mddev) struct md_rdev *rdev; if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) { - /* sync_work already queued. */ - clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + unregister_sync_thread(mddev); goto unlock; } @@ -9572,16 +9586,7 @@ void md_check_recovery(struct mddev *mddev) * still set. */ if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) { - if (!test_bit(MD_RECOVERY_DONE, &mddev->recovery)) { - /* resync/recovery still happening */ - clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery); - goto unlock; - } - - if (WARN_ON_ONCE(!mddev->sync_thread)) - goto unlock; - - md_reap_sync_thread(mddev); + unregister_sync_thread(mddev); goto unlock; } |