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authorNeilBrown <neilb@suse.com>2015-09-24 14:00:51 +1000
committerNeilBrown <neilb@suse.com>2015-10-02 17:23:43 +1000
commit88724bfa68be792c1487d759e87568c36ac1a1cc (patch)
tree12cf787a5922610396529d90ae82ccaf223a57d9
parentbcee19f424a0d8c26ecf2607b73c690802658b29 (diff)
downloadlinux-88724bfa68be792c1487d759e87568c36ac1a1cc.tar.gz
md: wait for pending superblock updates before switching to read-only
If a superblock update is pending, wait for it to complete before
letting md_set_readonly() switch to readonly.
Otherwise we might lose important information about a device having
failed.

For external arrays, waiting for superblock updates can wait on
user-space, so in that case, just return an error.

Reported-and-tested-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
-rw-r--r--drivers/md/md.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4f5ecbe94ccb..b8247bc32cf6 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5409,9 +5409,13 @@ static int md_set_readonly(struct mddev *mddev, struct block_device *bdev)
 		 * which will now never happen */
 		wake_up_process(mddev->sync_thread->tsk);
 
+	if (mddev->external && test_bit(MD_CHANGE_PENDING, &mddev->flags))
+		return -EBUSY;
 	mddev_unlock(mddev);
 	wait_event(resync_wait, !test_bit(MD_RECOVERY_RUNNING,
 					  &mddev->recovery));
+	wait_event(mddev->sb_wait,
+		   !test_bit(MD_CHANGE_PENDING, &mddev->flags));
 	mddev_lock_nointr(mddev);
 
 	mutex_lock(&mddev->open_mutex);