md: be careful when testing resync_max against curr_resync_completed. (c5e19d90) · Commits · 戴 / test

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>

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,

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