1 files changed, 41 insertions, 12 deletions

diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 288994ee7142..446827f98236 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -25,6 +25,11 @@
 
 #define DM_MSG_PREFIX "snapshots"
 
+static const char dm_snapshot_merge_target_name[] = "snapshot-merge";
+
+#define dm_target_is_snapshot_merge(ti) \
+        ((ti)->type->name == dm_snapshot_merge_target_name)
+
 /*
  * The percentage increment we will wake up users at
  */
@@ -1743,6 +1748,21 @@ static struct target_type snapshot_target = {
         .iterate_devices = snapshot_iterate_devices,
 };
 
+static struct target_type merge_target = {
+        .name    = dm_snapshot_merge_target_name,
+        .version = {1, 0, 0},
+        .module  = THIS_MODULE,
+        .ctr     = snapshot_ctr,
+        .dtr     = snapshot_dtr,
+        .map     = snapshot_map,
+        .end_io  = snapshot_end_io,
+        .postsuspend = snapshot_postsuspend,
+        .preresume  = snapshot_preresume,
+        .resume  = snapshot_resume,
+        .status  = snapshot_status,
+        .iterate_devices = snapshot_iterate_devices,
+};
+
 static int __init dm_snapshot_init(void)
 {
         int r;
@@ -1754,7 +1774,7 @@ static int __init dm_snapshot_init(void)
         }
 
         r = dm_register_target(&snapshot_target);
-        if (r) {
+        if (r < 0) {
                 DMERR("snapshot target register failed %d", r);
                 goto bad_register_snapshot_target;
         }
@@ -1762,34 +1782,40 @@ static int __init dm_snapshot_init(void)
         r = dm_register_target(&origin_target);
         if (r < 0) {
                 DMERR("Origin target register failed %d", r);
-                goto bad1;
+                goto bad_register_origin_target;
+        }
+
+        r = dm_register_target(&merge_target);
+        if (r < 0) {
+                DMERR("Merge target register failed %d", r);
+                goto bad_register_merge_target;
         }
 
         r = init_origin_hash();
         if (r) {
                 DMERR("init_origin_hash failed.");
-                goto bad2;
+                goto bad_origin_hash;
         }
 
         exception_cache = KMEM_CACHE(dm_exception, 0);
         if (!exception_cache) {
                 DMERR("Couldn't create exception cache.");
                 r = -ENOMEM;
-                goto bad3;
+                goto bad_exception_cache;
         }
 
         pending_cache = KMEM_CACHE(dm_snap_pending_exception, 0);
         if (!pending_cache) {
                 DMERR("Couldn't create pending cache.");
                 r = -ENOMEM;
-                goto bad4;
+                goto bad_pending_cache;
         }
 
         tracked_chunk_cache = KMEM_CACHE(dm_snap_tracked_chunk, 0);
         if (!tracked_chunk_cache) {
                 DMERR("Couldn't create cache to track chunks in use.");
                 r = -ENOMEM;
-                goto bad5;
+                goto bad_tracked_chunk_cache;
         }
 
         ksnapd = create_singlethread_workqueue("ksnapd");
@@ -1803,19 +1829,21 @@ static int __init dm_snapshot_init(void)
 
 bad_pending_pool:
         kmem_cache_destroy(tracked_chunk_cache);
-bad5:
+bad_tracked_chunk_cache:
         kmem_cache_destroy(pending_cache);
-bad4:
+bad_pending_cache:
         kmem_cache_destroy(exception_cache);
-bad3:
+bad_exception_cache:
         exit_origin_hash();
-bad2:
+bad_origin_hash:
+        dm_unregister_target(&merge_target);
+bad_register_merge_target:
         dm_unregister_target(&origin_target);
-bad1:
+bad_register_origin_target:
         dm_unregister_target(&snapshot_target);
-
 bad_register_snapshot_target:
         dm_exception_store_exit();
+
         return r;
 }
 
@@ -1825,6 +1853,7 @@ static void __exit dm_snapshot_exit(void)
 
         dm_unregister_target(&snapshot_target);
         dm_unregister_target(&origin_target);
+        dm_unregister_target(&merge_target);
 
         exit_origin_hash();
         kmem_cache_destroy(pending_cache);