Messages in this thread Patch in this message | | | From | Mike Snitzer <> | Subject | [PATCH v4 12/13] dm snapshot: redirect accesses to origin if merging snap invalidated | Date | Fri, 20 Nov 2009 15:27:52 -0500 |
| |
From: Mikulas Patocka <mpatocka@redhat.com>
If we are merging an invalidated snapshot, redirect all accesses to the origin device. This is safe because snapshot_merge_process() will stop_merge() if the merging snapshot becomes invalid.
Allowing the origin device to remain functional is important because it may contain the root filesystem.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> --- drivers/md/dm-snap.c | 9 ++++----- 1 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 2b5b083..74f7f38 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -1554,11 +1554,9 @@ static int snapshot_merge_map(struct dm_target *ti, struct bio *bio, down_write(&s->lock); - /* Full snapshots are not usable */ - if (!s->valid) { - r = -EIO; - goto out_unlock; - } + /* Full merging snapshots are redirected to the origin */ + if (!s->valid) + goto redirect_to_origin; /* If the block is already remapped - use that */ e = dm_lookup_exception(&s->complete, chunk); @@ -1581,6 +1579,7 @@ static int snapshot_merge_map(struct dm_target *ti, struct bio *bio, goto out_unlock; } + redirect_to_origin: bio->bi_bdev = s->origin->bdev; if (bio_rw(bio) == WRITE) { -- 1.6.5.2
| |