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Commit c5e19d90 authored by NeilBrown's avatar NeilBrown
Browse files

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: default avatarNeilBrown <neilb@suse.com>
parent a4a3d26d

drivers/md/md.c

+2 −1
Original line number Diff line number Diff line
@@ -7834,7 +7834,8 @@ void md_do_sync(struct md_thread *thread) 
		      > (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,

drivers/md/raid5.c

+2 −1
Original line number Diff line number Diff line
@@ -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,