* [PATCH] Revert "Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d""
@ 2024-01-25 8:21 Song Liu
2024-01-25 11:49 ` Yu Kuai
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Song Liu @ 2024-01-25 8:21 UTC (permalink / raw)
To: linux-raid; +Cc: yukuai1, Song Liu, Dan Moulding, stable, Junxiao Bi, Yu Kuai
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.
Reported-by: Dan Moulding <dan@danm.net>
Closes: https://lore.kernel.org/linux-raid/20240123005700.9302-1-dan@danm.net/
Fixes: bed9e27baf52 ("Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"")
Cc: stable@vger.kernel.org # v5.19+
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
[1] commit d6e035aad6c0 ("md: bypass block throttle for superblock update")
[2] commit bed9e27baf52 ("Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"")
---
drivers/md/raid5.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 8497880135ee..2b2f03705990 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -36,6 +36,7 @@
*/
#include <linux/blkdev.h>
+#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/raid/pq.h>
#include <linux/async_tx.h>
@@ -6773,7 +6774,18 @@ 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);
--
2.34.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] Revert "Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d""
2024-01-25 8:21 [PATCH] Revert "Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"" Song Liu
@ 2024-01-25 11:49 ` Yu Kuai
2024-01-25 15:48 ` Dan Moulding
2024-01-25 16:55 ` junxiao.bi
2 siblings, 0 replies; 4+ messages in thread
From: Yu Kuai @ 2024-01-25 11:49 UTC (permalink / raw)
To: Song Liu, linux-raid
Cc: yukuai1, Dan Moulding, stable, Junxiao Bi, yukuai (C)
在 2024/01/25 16:21, Song Liu 写道:
> 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.
>
> Reported-by: Dan Moulding<dan@danm.net>
> Closes:https://lore.kernel.org/linux-raid/20240123005700.9302-1-dan@danm.net/
> Fixes: bed9e27baf52 ("Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"")
> Cc:stable@vger.kernel.org # v5.19+
> Cc: Junxiao Bi<junxiao.bi@oracle.com>
> Cc: Yu Kuai<yukuai3@huawei.com>
> Signed-off-by: Song Liu<song@kernel.org>
>
> [1] commit d6e035aad6c0 ("md: bypass block throttle for superblock update")
> [2] commit bed9e27baf52 ("Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"")
LGTM
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] Revert "Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d""
2024-01-25 8:21 [PATCH] Revert "Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"" Song Liu
2024-01-25 11:49 ` Yu Kuai
@ 2024-01-25 15:48 ` Dan Moulding
2024-01-25 16:55 ` junxiao.bi
2 siblings, 0 replies; 4+ messages in thread
From: Dan Moulding @ 2024-01-25 15:48 UTC (permalink / raw)
To: song; +Cc: dan, junxiao.bi, linux-raid, stable, yukuai1, yukuai3
Thank you Song. Let me know if there is any more information I can
provide to help diagnose or reproduce this.
-- Dan
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Revert "Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d""
2024-01-25 8:21 [PATCH] Revert "Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"" Song Liu
2024-01-25 11:49 ` Yu Kuai
2024-01-25 15:48 ` Dan Moulding
@ 2024-01-25 16:55 ` junxiao.bi
2 siblings, 0 replies; 4+ messages in thread
From: junxiao.bi @ 2024-01-25 16:55 UTC (permalink / raw)
To: Song Liu, linux-raid; +Cc: yukuai1, Dan Moulding, stable, Yu Kuai
Should we get some understanding what is the issue before reverting the
commit? I am not clear what is the issue, already asked Dan in another
thread.
Thanks,
Junxiao.
On 1/25/24 12:21 AM, Song Liu wrote:
> 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.
>
> Reported-by: Dan Moulding <dan@danm.net>
> Closes: https://lore.kernel.org/linux-raid/20240123005700.9302-1-dan@danm.net/
> Fixes: bed9e27baf52 ("Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"")
> Cc: stable@vger.kernel.org # v5.19+
> Cc: Junxiao Bi <junxiao.bi@oracle.com>
> Cc: Yu Kuai <yukuai3@huawei.com>
> Signed-off-by: Song Liu <song@kernel.org>
>
> [1] commit d6e035aad6c0 ("md: bypass block throttle for superblock update")
> [2] commit bed9e27baf52 ("Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"")
> ---
> drivers/md/raid5.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index 8497880135ee..2b2f03705990 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -36,6 +36,7 @@
> */
>
> #include <linux/blkdev.h>
> +#include <linux/delay.h>
> #include <linux/kthread.h>
> #include <linux/raid/pq.h>
> #include <linux/async_tx.h>
> @@ -6773,7 +6774,18 @@ 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);
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-01-25 16:55 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2024-01-25 8:21 [PATCH] Revert "Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"" Song Liu
2024-01-25 11:49 ` Yu Kuai
2024-01-25 15:48 ` Dan Moulding
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