3 files changed, 26 insertions, 17 deletions

diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c
index 2b7907b6dd09..0bdb201c2c2a 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -173,7 +173,9 @@ int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
 
         /* Validate the chunk size against the device block size */
         if (chunk_size %
-            (bdev_logical_block_size(dm_snap_cow(store->snap)->bdev) >> 9)) {
+            (bdev_logical_block_size(dm_snap_cow(store->snap)->bdev) >> 9) ||
+            chunk_size %
+            (bdev_logical_block_size(dm_snap_origin(store->snap)->bdev) >> 9)) {
                 *error = "Chunk size is not a multiple of device blocksize";
                 return -EINVAL;
         }
diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h
index e8dfa06af3ba..0b2536247cf5 100644
--- a/drivers/md/dm-exception-store.h
+++ b/drivers/md/dm-exception-store.h
@@ -126,8 +126,9 @@ struct dm_exception_store {
 };
 
 /*
- * Obtain the cow device used by a given snapshot.
+ * Obtain the origin or cow device used by a given snapshot.
  */
+struct dm_dev *dm_snap_origin(struct dm_snapshot *snap);
 struct dm_dev *dm_snap_cow(struct dm_snapshot *snap);
 
 /*
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index a6ab98920cc3..a1f2ab553b92 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -148,6 +148,12 @@ struct dm_snapshot {
 #define RUNNING_MERGE          0
 #define SHUTDOWN_MERGE         1
 
+struct dm_dev *dm_snap_origin(struct dm_snapshot *s)
+{
+        return s->origin;
+}
+EXPORT_SYMBOL(dm_snap_origin);
+
 struct dm_dev *dm_snap_cow(struct dm_snapshot *s)
 {
         return s->cow;
@@ -1065,10 +1071,6 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
                 origin_mode = FMODE_WRITE;
         }
 
-        origin_path = argv[0];
-        argv++;
-        argc--;
-
         s = kmalloc(sizeof(*s), GFP_KERNEL);
         if (!s) {
                 ti->error = "Cannot allocate snapshot context private "
@@ -1077,6 +1079,16 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
                 goto bad;
         }
 
+        origin_path = argv[0];
+        argv++;
+        argc--;
+
+        r = dm_get_device(ti, origin_path, origin_mode, &s->origin);
+        if (r) {
+                ti->error = "Cannot get origin device";
+                goto bad_origin;
+        }
+
         cow_path = argv[0];
         argv++;
         argc--;
@@ -1097,12 +1109,6 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
         argv += args_used;
         argc -= args_used;
 
-        r = dm_get_device(ti, origin_path, origin_mode, &s->origin);
-        if (r) {
-                ti->error = "Cannot get origin device";
-                goto bad_origin;
-        }
-
         s->ti = ti;
         s->valid = 1;
         s->active = 0;
@@ -1212,15 +1218,15 @@ bad_kcopyd:
         dm_exception_table_exit(&s->complete, exception_cache);
 
 bad_hash_tables:
-        dm_put_device(ti, s->origin);
-
-bad_origin:
         dm_exception_store_destroy(s->store);
 
 bad_store:
         dm_put_device(ti, s->cow);
 
 bad_cow:
+        dm_put_device(ti, s->origin);
+
+bad_origin:
         kfree(s);
 
 bad:
@@ -1314,12 +1320,12 @@ static void snapshot_dtr(struct dm_target *ti)
 
         mempool_destroy(s->pending_pool);
 
-        dm_put_device(ti, s->origin);
-
         dm_exception_store_destroy(s->store);
 
         dm_put_device(ti, s->cow);
 
+        dm_put_device(ti, s->origin);
+
         kfree(s);
 }