Commit f71209b1 authored May 29, 2023 by Yu Kuai Committed by Song Liu Jul 27, 2023

md: enhance checking in md_check_recovery()



For md_check_recovery():

1) if 'MD_RECOVERY_RUNING' is not set, register new sync_thread.
2) if 'MD_RECOVERY_RUNING' is set:
 a) if 'MD_RECOVERY_DONE' is not set, don't do anything, wait for
   md_do_sync() to be done.
 b) if 'MD_RECOVERY_DONE' is set, unregister sync_thread. Current code
   expects that sync_thread is not NULL, otherwise new sync_thread will
   be registered, which will corrupt the array.

Make sure md_check_recovery() won't register new sync_thread if
'MD_RECOVERY_RUNING' is still set, and a new WARN_ON_ONCE() is added for
the above corruption,

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529132037.2124527-7-yukuai1@huaweicloud.com

parent 753260ed

drivers/md/md.c

+15 −7

Original line number	Diff line number	Diff line
		@@ -9388,16 +9388,24 @@ void md_check_recovery(struct mddev *mddev)
		if (mddev->sb_flags)
		md_update_sb(mddev, 0);

		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
		!test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
		/*
		* Never start a new sync thread if MD_RECOVERY_RUNNING is
		* 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 (mddev->sync_thread) {

		if (WARN_ON_ONCE(!mddev->sync_thread))
		goto unlock;

		md_reap_sync_thread(mddev);
		goto unlock;
		}

		/* Set RUNNING before clearing NEEDED to avoid
		* any transients in the value of "sync_action".
		*/