1 files changed, 18 insertions, 11 deletions

diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 87727d84dbba..f3759dd7828e 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -373,16 +373,11 @@ static inline ulong round_up(ulong n, ulong size)
 
 static void read_snapshot_metadata(struct dm_snapshot *s)
 {
-        if (s->have_metadata)
-                return;
-
         if (s->store.read_metadata(&s->store)) {
                 down_write(&s->lock);
                 s->valid = 0;
                 up_write(&s->lock);
         }
-
-        s->have_metadata = 1;
 }
 
 /*
@@ -471,7 +466,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
         s->chunk_shift = ffs(chunk_size) - 1;
 
         s->valid = 1;
-        s->have_metadata = 0;
+        s->active = 0;
         s->last_percent = 0;
         init_rwsem(&s->lock);
         s->table = ti->table;
@@ -506,7 +501,11 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
                 goto bad5;
         }
 
+        /* Metadata must only be loaded into one table at once */
+        read_snapshot_metadata(s);
+
         /* Add snapshot to the list of snapshots for this origin */
+        /* Exceptions aren't triggered till snapshot_resume() is called */
         if (register_snapshot(s)) {
                 r = -EINVAL;
                 ti->error = "Cannot register snapshot origin";
@@ -793,6 +792,9 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
         if (!s->valid)
                 return -EIO;
 
+        if (unlikely(bio_barrier(bio)))
+                return -EOPNOTSUPP;
+
         /*
          * Write to snapshot - higher level takes care of RW/RO
          * flags so we should only get this if we are
@@ -862,7 +864,9 @@ static void snapshot_resume(struct dm_target *ti)
 {
         struct dm_snapshot *s = (struct dm_snapshot *) ti->private;
 
-        read_snapshot_metadata(s);
+        down_write(&s->lock);
+        s->active = 1;
+        up_write(&s->lock);
 }
 
 static int snapshot_status(struct dm_target *ti, status_type_t type,
@@ -932,8 +936,8 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio)
         /* Do all the snapshots on this origin */
         list_for_each_entry (snap, snapshots, list) {
 
-                /* Only deal with valid snapshots */
-                if (!snap->valid)
+                /* Only deal with valid and active snapshots */
+                if (!snap->valid || !snap->active)
                         continue;
 
                 /* Nothing to do if writing beyond end of snapshot */
@@ -1057,6 +1061,9 @@ static int origin_map(struct dm_target *ti, struct bio *bio,
         struct dm_dev *dev = (struct dm_dev *) ti->private;
         bio->bi_bdev = dev->bdev;
 
+        if (unlikely(bio_barrier(bio)))
+                return -EOPNOTSUPP;
+
         /* Only tell snapshots if this is a write */
         return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : 1;
 }
@@ -1104,7 +1111,7 @@ static int origin_status(struct dm_target *ti, status_type_t type, char *result,
 
 static struct target_type origin_target = {
         .name    = "snapshot-origin",
-        .version = {1, 0, 1},
+        .version = {1, 1, 0},
         .module  = THIS_MODULE,
         .ctr     = origin_ctr,
         .dtr     = origin_dtr,
@@ -1115,7 +1122,7 @@ static struct target_type origin_target = {
 
 static struct target_type snapshot_target = {
         .name    = "snapshot",
-        .version = {1, 0, 1},
+        .version = {1, 1, 0},
         .module  = THIS_MODULE,
         .ctr     = snapshot_ctr,
         .dtr     = snapshot_dtr,