| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 076/193] md: fix deadlock error in recent patch. | Date | Tue, 28 Nov 2017 11:25:23 +0100 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: NeilBrown <neilb@suse.com>
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: cc27b0c78c79 ("md: fix deadlock between mddev_suspend() and md_write_start()") Reported-by: Xiao Ni <xni@redhat.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/md/md.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8039,7 +8039,8 @@ bool md_write_start(struct mddev *mddev, 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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