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Commit 459aad50 authored by NeilBrown's avatar NeilBrown Committed by Greg Kroah-Hartman
Browse files

md: fix deadlock error in recent patch. 



commit d47c8ad261f787af22a220ffcc2d07afba809223 upstream.

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()")
Reported-by: default avatarXiao Ni <xni@redhat.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 55e357bc

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;