This is a note to let you know that I've just added the patch titled
Revert "Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d""
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
revert-revert-md-raid5-wait-for-md_sb_change_pending.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 19975ad2eaf6c29185953381f42722e7d03e0562
Author: Song Liu <song@xxxxxxxxxx>
Date: Thu Jan 25 00:21:31 2024 -0800
Revert "Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d""
[ Upstream commit 3445139e3a594be77eff48bc17eff67cf983daed ]
This reverts commit bed9e27baf52a09b7ba2a3714f1e24e17ced386d.
The original set [1][2] was expected to undo a suboptimal fix in [2], and
replace it with a better fix [1]. However, as reported by Dan Moulding [2]
causes an issue with raid5 with journal device.
Revert [2] for now to close the issue. We will follow up on another issue
reported by Juxiao Bi, as [2] is expected to fix it. We believe this is a
good trade-off, because the latter issue happens less freqently.
In the meanwhile, we will NOT revert [1], as it contains the right logic.
[1] commit d6e035aad6c0 ("md: bypass block throttle for superblock update")
[2] commit bed9e27baf52 ("Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"")
Reported-by: Dan Moulding <dan@xxxxxxxx>
Closes: https://lore.kernel.org/linux-raid/20240123005700.9302-1-dan@xxxxxxxx/
Fixes: bed9e27baf52 ("Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"")
Cc: stable@xxxxxxxxxxxxxxx # v5.19+
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Yu Kuai <yukuai3@xxxxxxxxxx>
Signed-off-by: Song Liu <song@xxxxxxxxxx>
Reviewed-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240125082131.788600-1-song@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index e2fcc09a18cdb..b98abe927d06b 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -44,6 +44,7 @@
*/
#include <linux/blkdev.h>
+#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/raid/pq.h>
#include <linux/async_tx.h>
@@ -6329,7 +6330,18 @@ static void raid5d(struct md_thread *thread)
spin_unlock_irq(&conf->device_lock);
md_check_recovery(mddev);
spin_lock_irq(&conf->device_lock);
+
+ /*
+ * Waiting on MD_SB_CHANGE_PENDING below may deadlock
+ * seeing md_check_recovery() is needed to clear
+ * the flag when using mdmon.
+ */
+ continue;
}
+
+ wait_event_lock_irq(mddev->sb_wait,
+ !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
+ conf->device_lock);
}
pr_debug("%d stripes handled\n", handled);
