Btrfs: change how subvolumes are organized

[linux-2.6-block.git] / fs / btrfs / root-tree.c

diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 0ddc6d61c55a7135bd94c15c76644011c6e9fd4c..5ef72599a581d0b2894a16373ab93b2ca57cd490 100644 (file)
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -278,31 +278,57 @@ out:
        return ret;
 }
 
-#if 0 /* this will get used when snapshot deletion is implemented */
 int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
                       struct btrfs_root *tree_root,
-                      u64 root_id, u8 type, u64 ref_id)
+                      u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
+                      const char *name, int name_len)
+
 {
+       struct btrfs_path *path;
+       struct btrfs_root_ref *ref;
+       struct extent_buffer *leaf;
        struct btrfs_key key;
+       unsigned long ptr;
+       int err = 0;
        int ret;
-       struct btrfs_path *path;
 
        path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
 
        key.objectid = root_id;
-       key.type = type;
+       key.type = BTRFS_ROOT_BACKREF_KEY;
        key.offset = ref_id;
-
+again:
        ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
-       BUG_ON(ret);
-
-       ret = btrfs_del_item(trans, tree_root, path);
-       BUG_ON(ret);
+       BUG_ON(ret < 0);
+       if (ret == 0) {
+               leaf = path->nodes[0];
+               ref = btrfs_item_ptr(leaf, path->slots[0],
+                                    struct btrfs_root_ref);
+
+               WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
+               WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
+               ptr = (unsigned long)(ref + 1);
+               WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
+               *sequence = btrfs_root_ref_sequence(leaf, ref);
+
+               ret = btrfs_del_item(trans, tree_root, path);
+               BUG_ON(ret);
+       } else
+               err = -ENOENT;
+
+       if (key.type == BTRFS_ROOT_BACKREF_KEY) {
+               btrfs_release_path(tree_root, path);
+               key.objectid = ref_id;
+               key.type = BTRFS_ROOT_REF_KEY;
+               key.offset = root_id;
+               goto again;
+       }
 
        btrfs_free_path(path);
-       return ret;
+       return err;
 }
-#endif
 
 int btrfs_find_root_ref(struct btrfs_root *tree_root,
                   struct btrfs_path *path,
@@ -319,7 +345,6 @@ int btrfs_find_root_ref(struct btrfs_root *tree_root,
        return ret;
 }
 
-
 /*
  * add a btrfs_root_ref item.  type is either BTRFS_ROOT_REF_KEY
  * or BTRFS_ROOT_BACKREF_KEY.
@@ -335,8 +360,7 @@ int btrfs_find_root_ref(struct btrfs_root *tree_root,
  */
 int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
                       struct btrfs_root *tree_root,
-                      u64 root_id, u8 type, u64 ref_id,
-                      u64 dirid, u64 sequence,
+                      u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
                       const char *name, int name_len)
 {
        struct btrfs_key key;
@@ -346,13 +370,14 @@ int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
        struct extent_buffer *leaf;
        unsigned long ptr;
 
-
        path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
 
        key.objectid = root_id;
-       key.type = type;
+       key.type = BTRFS_ROOT_BACKREF_KEY;
        key.offset = ref_id;
-
+again:
        ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
                                      sizeof(*ref) + name_len);
        BUG_ON(ret);
@@ -366,6 +391,14 @@ int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
        write_extent_buffer(leaf, name, ptr, name_len);
        btrfs_mark_buffer_dirty(leaf);
 
+       if (key.type == BTRFS_ROOT_BACKREF_KEY) {
+               btrfs_release_path(tree_root, path);
+               key.objectid = ref_id;
+               key.type = BTRFS_ROOT_REF_KEY;
+               key.offset = root_id;
+               goto again;
+       }
+
        btrfs_free_path(path);
-       return ret;
+       return 0;
 }