md/raid5: consider updating reshape_position at start of reshape.

md/raid5 only updates ->reshape_position (which is stored in
metadata and is authoritative) occasionally, but particularly
when getting closed to ->resync_max as it must be correct
when ->resync_max is reached.

When mdadm tries to stop an array which is reshaping it will:
 - freeze the reshape,
 - set resync_max to where the reshape has reached.
 - unfreeze the reshape.
When this happens, the reshape is aborted and then restarted.

The restart doesn't check that resync_max is close, and so doesn't
update ->reshape_position like it should.
This results in the reshape stopping, but ->reshape_position being
incorrect.

So on that first call to reshape_request, make sure ->reshape_position
is updated if needed.

Signed-off-by: NeilBrown <neilb@suse.com>
This commit is contained in:
NeilBrown 2015-07-06 12:28:45 +10:00
parent 985ca973b6
commit 92140480ed

View File

@ -5347,6 +5347,7 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk
sector_t stripe_addr;
int reshape_sectors;
struct list_head stripes;
sector_t retn;
if (sector_nr == 0) {
/* If restarting in the middle, skip the initial sectors */
@ -5362,7 +5363,8 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk
mddev->curr_resync_completed = sector_nr;
sysfs_notify(&mddev->kobj, NULL, "sync_completed");
*skipped = 1;
return sector_nr;
retn = sector_nr;
goto finish;
}
}
@ -5535,6 +5537,8 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk
* then we need to write out the superblock.
*/
sector_nr += reshape_sectors;
retn = reshape_sectors;
finish:
if ((sector_nr - mddev->curr_resync_completed) * 2
>= mddev->resync_max - mddev->curr_resync_completed) {
/* Cannot proceed until we've updated the superblock... */
@ -5560,7 +5564,7 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk
sysfs_notify(&mddev->kobj, NULL, "sync_completed");
}
ret:
return reshape_sectors;
return retn;
}
static inline sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped)