From 88724bfa68be792c1487d759e87568c36ac1a1cc Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 24 Sep 2015 14:00:51 +1000 Subject: [PATCH] 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 Signed-off-by: NeilBrown --- drivers/md/md.c | 4 ++++ 1 file changed, 4 insertions(+) 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); -- 2.20.1