Re: [PATCH -next] md/raid5: don't allow concurrent reshape with recovery

From: Paul Menzel
Date: Mon May 29 2023 - 02:45:25 EST

Dear Yu,

Thank you for your patch. As always some minor commons, you can also ignore.

Am 29.05.23 um 05:10 schrieb Yu Kuai:
From: Yu Kuai <yukuai3@xxxxxxxxxx>

commit 0aecb06e2249 ("md/raid5: don't allow replacement while reshape

I’d start with a capital letter: Commit …

is in progress") fix that replacement can be set if reshape is


interrupted, which will cause that array can't be assemebled.


There is a similar on the other side, if recovery is interrupted, then

similar *problem*?

reshape can start, which will cause the same problem.

Fix the prblem by don't start reshape is recovery is still in progress.

• problem
• … by not starting to reshape while recovery is still in progress

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
drivers/md/raid5.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 64865f9dd3f5..6db783ca71b7 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -8500,6 +8500,7 @@ static int raid5_start_reshape(struct mddev *mddev)
struct r5conf *conf = mddev->private;
struct md_rdev *rdev;
int spares = 0;
+ int i;

It won’t make a difference for the code I believe, but as the count variable can’t be negative, I’d use `unsigned int`.

unsigned long flags;
if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
@@ -8511,6 +8512,13 @@ static int raid5_start_reshape(struct mddev *mddev)
if (has_failed(conf))
return -EINVAL;
+ /* raid5 can't handle concurrent reshape and recovery */
+ if (mddev->recovery_cp < MaxSector)
+ return -EBUSY;
+ for (i = 0; i < conf->raid_disks; i++)
+ if (rdev_mdlock_deref(mddev, conf->disks[i].replacement))
+ return -EBUSY;
rdev_for_each(rdev, mddev) {
if (!test_bit(In_sync, &rdev->flags)
&& !test_bit(Faulty, &rdev->flags))

Kind regards,