Commit d47c8ad2 authored Oct 05, 2017 by NeilBrown Committed by Shaohua Li Oct 05, 2017

md: fix deadlock error in recent patch.



A recent patch aimed to cause md_write_start() to fail (rather than
block) when the mddev was suspending, so as to avoid deadlocks.
Unfortunately the test in wait_event() was wrong, and it didn't change
behaviour at all.

We wait_event() must wait until the metadata is written OR the array is
suspending.

Fixes: cc27b0c7 ("md: fix deadlock between mddev_suspend() and md_write_start()")
Cc: stable@vger.kernel.org
Reported-by: Xiao Ni <xni@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

parent 9e66317d

drivers/md/md.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -8039,7 +8039,8 @@ bool md_write_start(struct mddev mddev, struct bio bi)
		if (did_change)
		sysfs_notify_dirent_safe(mddev->sysfs_state);
		wait_event(mddev->sb_wait,
		!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) && !mddev->suspended);
		!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) \|\|
		mddev->suspended);
		if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
		percpu_ref_put(&mddev->writes_pending);
		return false;

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