From c5e19d906a658f27fa858b09a95d9551b1a69bd0 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Fri, 17 Jul 2015 12:06:02 +1000 Subject: md: be careful when testing resync_max against curr_resync_completed. While it generally shouldn't happen, it is not impossible for curr_resync_completed to exceed resync_max. This can particularly happen when reshaping RAID5 - the current status isn't copied to curr_resync_completed promptly, so when it is, it can exceed resync_max. This happens when the reshape is 'frozen', resync_max is set low, and reshape is re-enabled. Taking a difference between two unsigned numbers is always dangerous anyway, so add a test to behave correctly if curr_resync_completed > resync_max Signed-off-by: NeilBrown --- drivers/md/raid5.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/md/raid5.c') diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 19bbdbe..1c27aa1 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5542,7 +5542,8 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk sector_nr += reshape_sectors; retn = reshape_sectors; finish: - if ((sector_nr - mddev->curr_resync_completed) * 2 + if (mddev->curr_resync_completed > mddev->resync_max || + (sector_nr - mddev->curr_resync_completed) * 2 >= mddev->resync_max - mddev->curr_resync_completed) { /* Cannot proceed until we've updated the superblock... */ wait_event(conf->wait_for_overlap, -- cgit v1.1