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

[Yu Kuai]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

commit 0aecb06e2249 ("md/raid5: don't allow replacement while reshape
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
reshape can start, which will cause the same problem.

Fix the prblem by don't start reshape is 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;
 	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))
-- 
2.39.2