unsigned *bits);
 void btrfs_clear_delalloc_extent(struct inode *inode,
                                 struct extent_state *state, unsigned *bits);
+void btrfs_merge_delalloc_extent(struct inode *inode, struct extent_state *new,
+                                struct extent_state *other);
 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
                         size_t size, struct bio *bio,
                         unsigned long bio_flags);
 
        return tree_search_for_insert(tree, offset, NULL, NULL);
 }
 
-static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
-                    struct extent_state *other)
-{
-       if (tree->ops && tree->ops->merge_extent_hook)
-               tree->ops->merge_extent_hook(tree->private_data, new, other);
-}
-
 /*
  * utility function to look for merge candidates inside a given range.
  * Any extents with matching state are merged together into a single
                other = rb_entry(other_node, struct extent_state, rb_node);
                if (other->end == state->start - 1 &&
                    other->state == state->state) {
-                       merge_cb(tree, state, other);
+                       if (tree->private_data &&
+                           is_data_inode(tree->private_data))
+                               btrfs_merge_delalloc_extent(tree->private_data,
+                                                           state, other);
                        state->start = other->start;
                        rb_erase(&other->rb_node, &tree->state);
                        RB_CLEAR_NODE(&other->rb_node);
                other = rb_entry(other_node, struct extent_state, rb_node);
                if (other->start == state->end + 1 &&
                    other->state == state->state) {
-                       merge_cb(tree, state, other);
+                       if (tree->private_data &&
+                           is_data_inode(tree->private_data))
+                               btrfs_merge_delalloc_extent(tree->private_data,
+                                                           state, other);
                        state->end = other->end;
                        rb_erase(&other->rb_node, &tree->state);
                        RB_CLEAR_NODE(&other->rb_node);
 
        /*
         * Optional hooks, called if the pointer is not NULL
         */
-       void (*merge_extent_hook)(void *private_data,
-                                 struct extent_state *new,
-                                 struct extent_state *other);
        void (*split_extent_hook)(void *private_data,
                                  struct extent_state *orig, u64 split);
 };
 
                u64 new_size;
 
                /*
-                * See the explanation in btrfs_merge_extent_hook, the same
+                * See the explanation in btrfs_merge_delalloc_extent, the same
                 * applies here, just in reverse.
                 */
                new_size = orig->end - split + 1;
 }
 
 /*
- * extent_io.c merge_extent_hook, used to track merged delayed allocation
- * extents so we can keep track of new extents that are just merged onto old
- * extents, such as when we are doing sequential writes, so we can properly
- * account for the metadata space we'll need.
+ * Handle merged delayed allocation extents so we can keep track of new extents
+ * that are just merged onto old extents, such as when we are doing sequential
+ * writes, so we can properly account for the metadata space we'll need.
  */
-static void btrfs_merge_extent_hook(void *private_data,
-                                   struct extent_state *new,
-                                   struct extent_state *other)
+void btrfs_merge_delalloc_extent(struct inode *inode, struct extent_state *new,
+                                struct extent_state *other)
 {
-       struct inode *inode = private_data;
        u64 new_size, old_size;
        u32 num_extents;
 
        .readpage_io_failed_hook = btrfs_readpage_io_failed_hook,
 
        /* optional callbacks */
-       .merge_extent_hook = btrfs_merge_extent_hook,
        .split_extent_hook = btrfs_split_extent_hook,
 };