From: Milan Broz Allow invalid snapshots to be activated instead of failing. This allows userspace to reinstate any given snapshot state - for example after an unscheduled reboot - and clean up the invalid snapshot at its leisure. Cc: stable@kernel.org Signed-off-by: Milan Broz Signed-off-by: Alasdair G Kergon --- drivers/md/dm-exception-store.c | 11 ++++++----- drivers/md/dm-snap.c | 5 ++++- 2 files changed, 10 insertions(+), 6 deletions(-) Index: linux/drivers/md/dm-exception-store.c =================================================================== --- linux.orig/drivers/md/dm-exception-store.c 2007-07-12 17:04:03.000000000 +0100 +++ linux/drivers/md/dm-exception-store.c 2007-07-12 17:04:04.000000000 +0100 @@ -489,11 +489,6 @@ static int persistent_read_metadata(stru /* * Sanity checks. */ - if (!ps->valid) { - DMWARN("snapshot is marked invalid"); - return -EINVAL; - } - if (ps->version != SNAPSHOT_DISK_VERSION) { DMWARN("unable to handle snapshot disk version %d", ps->version); @@ -501,6 +496,12 @@ static int persistent_read_metadata(stru } /* + * Metadata are valid, but snapshot is invalidated + */ + if (!ps->valid) + return 1; + + /* * Read the metadata. */ r = read_exceptions(ps); Index: linux/drivers/md/dm-snap.c =================================================================== --- linux.orig/drivers/md/dm-snap.c 2007-07-12 17:03:58.000000000 +0100 +++ linux/drivers/md/dm-snap.c 2007-07-12 17:04:04.000000000 +0100 @@ -523,9 +523,12 @@ static int snapshot_ctr(struct dm_target /* Metadata must only be loaded into one table at once */ r = s->store.read_metadata(&s->store); - if (r) { + if (r < 0) { ti->error = "Failed to read snapshot metadata"; goto bad6; + } else if (r > 0) { + s->valid = 0; + DMWARN("Snapshot is marked invalid."); } bio_list_init(&s->queued_bios);