From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
If we are merging invalidated snapshot, redirect all accesses to the origin
device.
Userspace code will remove the invalidated snapshot anyway after a few seconds,
but during this period, the origin device must be active (it may for example
contain root filesystem and having unbootable computer is not desirable).
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Reviewed-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
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 8060fe3..e0d0c30 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -1458,11 +1458,9 @@ 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 = lookup_exception(&s->complete, chunk);
@@ -1486,6 +1484,7 @@ 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) {
--
1.6.2.5
--
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