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 <neilb@suse.com>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 5b62a3d..b326cd2 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -7834,7 +7834,8 @@
> (max_sectors >> 4)) ||
time_after_eq(jiffies, update_time + UPDATE_FREQUENCY) ||
(j - mddev->curr_resync_completed)*2
- >= mddev->resync_max - mddev->curr_resync_completed
+ >= mddev->resync_max - mddev->curr_resync_completed ||
+ mddev->curr_resync_completed > mddev->resync_max
)) {
/* time to update curr_resync_completed */
wait_event(mddev->recovery_wait,