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| author |   Mike Snitzer <snitzer@redhat.com> | 2015-10-08 18:05:41 -0400 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2015-10-09 16:57:03 -0400 |
| commit | b0d3cc011e532d8c9db76cf717bcafa53c135595 (patch) | |
| tree | d74330dcf71a599d637a7eecad8b56cdbd4487b9 /drivers/md/dm-snap.c | |
| parent | dm cache: fix NULL pointer when switching from cleaner policy (diff) | |
| download | linux-dev-b0d3cc011e532d8c9db76cf717bcafa53c135595.tar.xz linux-dev-b0d3cc011e532d8c9db76cf717bcafa53c135595.zip | |
dm snapshot: add new persistent store option to support overflow
Commit 76c44f6d80 introduced the possibly for "Overflow" to be reported
by the snapshot device's status. Older userspace (e.g. lvm2) does not
handle the "Overflow" status response.
Fix this incompatibility by requiring newer userspace code, that can
cope with "Overflow", request the persistent store with overflow support
by using "PO" (Persistent with Overflow) for the snapshot store type.
Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Fixes: 76c44f6d80 ("dm snapshot: don't invalidate on-disk image on snapshot write overflow")
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-snap.c')
| -rw-r--r-- | drivers/md/dm-snap.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index c0bcd6516dfe..c06b74e91cd6 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -1098,7 +1098,7 @@ static void stop_merge(struct dm_snapshot *s) } /* - * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> + * Construct a snapshot mapping: <origin_dev> <COW-dev> <p|po|n> <chunk-size> */ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) { @@ -1302,6 +1302,7 @@ static void __handover_exceptions(struct dm_snapshot *snap_src, u.store_swap = snap_dest->store; snap_dest->store = snap_src->store; + snap_dest->store->userspace_supports_overflow = u.store_swap->userspace_supports_overflow; snap_src->store = u.store_swap; snap_dest->store->snap = snap_dest; @@ -1739,8 +1740,11 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio) pe = __find_pending_exception(s, pe, chunk); if (!pe) { - s->snapshot_overflowed = 1; - DMERR("Snapshot overflowed: Unable to allocate exception."); + if (s->store->userspace_supports_overflow) { + s->snapshot_overflowed = 1; + DMERR("Snapshot overflowed: Unable to allocate exception."); + } else + __invalidate_snapshot(s, -ENOMEM); r = -EIO; goto out_unlock; } @@ -2365,7 +2369,7 @@ static struct target_type origin_target = { static struct target_type snapshot_target = { .name = "snapshot", - .version = {1, 14, 0}, + .version = {1, 15, 0}, .module = THIS_MODULE, .ctr = snapshot_ctr, .dtr = snapshot_dtr, @@ -2379,7 +2383,7 @@ static struct target_type snapshot_target = { static struct target_type merge_target = { .name = dm_snapshot_merge_target_name, - .version = {1, 3, 0}, + .version = {1, 4, 0}, .module = THIS_MODULE, .ctr = snapshot_ctr, .dtr = snapshot_dtr, |