If, while assembling an array, we find a device which is not fully
in-sync with the array, it is important to set the "fullsync" flags.
This is an exact analog to the setting of this flag in hot_add_disk
methods.
Currently, only v1.x metadata supports having devices in an array
which are not fully in-sync (it keep track of how in sync they are).
The 'fullsync' flag only makes a difference when a write-intent bitmap
is being used. In this case it tells recovery to ignore the bitmap
and recovery all blocks.
This fix is already in place for raid1, but not raid5/6 or raid10.
So without this fix, a raid1 ir raid4/5/6 array with version 1.x
metadata and a write intent bitmaps, that is stopped in the middle
of a recovery, will appear to complete the recovery instantly
after it is reassembled, but the recovery will not be correct.
If you might have an array like that, issueing
echo repair > /sys/block/mdXX/md/sync_action
will make sure recovery completes properly.
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Neil Brown <neilb@xxxxxxx>
### Diffstat output
./drivers/md/raid10.c | 2 ++
./drivers/md/raid5.c | 4 +++-
2 files changed, 5 insertions(+), 1 deletion(-)
diff .prev/drivers/md/raid10.c ./drivers/md/raid10.c
--- .prev/drivers/md/raid10.c 2008-06-27 15:14:05.000000000 +1000
+++ ./drivers/md/raid10.c 2008-06-27 15:19:36.000000000 +1000
@@ -2137,6 +2137,8 @@ static int run(mddev_t *mddev)
!test_bit(In_sync, &disk->rdev->flags)) {
disk->head_position = 0;
mddev->degraded++;
+ if (disk->rdev)
+ conf->fullsync = 1;
}
}
diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c 2008-06-27 15:14:05.000000000 +1000
+++ ./drivers/md/raid5.c 2008-06-27 15:19:36.000000000 +1000
@@ -4305,7 +4305,9 @@ static int run(mddev_t *mddev)
" disk %d\n", bdevname(rdev->bdev,b),
raid_disk);
working_disks++;
- }
+ } else
+ /* Cannot rely on bitmap to complete recovery */
+ conf->fullsync = 1;
}
/*
--
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