btrfs: cleanup: removed unused 'btrfs_get_inode_ref_index'

Found by uselex.rb:
> btrfs_get_inode_ref_index: [R]: exported from:
fs/btrfs/inode-item.o fs/btrfs/btrfs.o fs/btrfs/built-in.o

Signed-off-by: Sergei Trofimovich <[e-mail]>
Reviewed-by: David Stebra <[e-mail]>
Signed-off-by: Wang Shilong <[e-mail]>
Signed-off-by: Josef Bacik <[e-mail]>
Signed-off-by: Chris Mason <[e-mail]>

fs/btrfs/ctree.h

···
 			   struct btrfs_root *root,
 			   const char *name, int name_len,
 			   u64 inode_objectid, u64 ref_objectid, u64 *index);
-int btrfs_get_inode_ref_index(struct btrfs_trans_handle *trans,
-			      struct btrfs_root *root,
-			      struct btrfs_path *path,
-			      const char *name, int name_len,
-			      u64 inode_objectid, u64 ref_objectid, int mod,
-			      u64 *ret_index);
 int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *root,
 			     struct btrfs_path *path, u64 objectid);

fs/btrfs/inode-item.c

···
 	return 0;
 }
 
-static struct btrfs_inode_ref *
-btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
-		       struct btrfs_root *root,
-		       struct btrfs_path *path,
-		       const char *name, int name_len,
-		       u64 inode_objectid, u64 ref_objectid, int ins_len,
-		       int cow)
-{
-	int ret;
-	struct btrfs_key key;
-	struct btrfs_inode_ref *ref;
-
-	key.objectid = inode_objectid;
-	key.type = BTRFS_INODE_REF_KEY;
-	key.offset = ref_objectid;
-
-	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
-	if (ret < 0)
-		return ERR_PTR(ret);
-	if (ret > 0)
-		return NULL;
-	if (!find_name_in_backref(path, name, name_len, &ref))
-		return NULL;
-	return ref;
-}
-
 /* Returns NULL if no extref found */
 struct btrfs_inode_extref *
 btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
···
 	if (!btrfs_find_name_in_ext_backref(path, ref_objectid, name, name_len, &extref))
 		return NULL;
 	return extref;
-}
-
-int btrfs_get_inode_ref_index(struct btrfs_trans_handle *trans,
-			      struct btrfs_root *root,
-			      struct btrfs_path *path,
-			      const char *name, int name_len,
-			      u64 inode_objectid, u64 ref_objectid, int mod,
-			      u64 *ret_index)
-{
-	struct btrfs_inode_ref *ref;
-	struct btrfs_inode_extref *extref;
-	int ins_len = mod < 0 ? -1 : 0;
-	int cow = mod != 0;
-
-	ref = btrfs_lookup_inode_ref(trans, root, path, name, name_len,
-				     inode_objectid, ref_objectid, ins_len,
-				     cow);
-	if (IS_ERR(ref))
-		return PTR_ERR(ref);
-
-	if (ref != NULL) {
-		*ret_index = btrfs_inode_ref_index(path->nodes[0], ref);
-		return 0;
-	}
-
-	btrfs_release_path(path);
-
-	extref = btrfs_lookup_inode_extref(trans, root, path, name,
-					   name_len, inode_objectid,
-					   ref_objectid, ins_len, cow);
-	if (IS_ERR(extref))
-		return PTR_ERR(extref);
-
-	if (extref) {
-		*ret_index = btrfs_inode_extref_index(path->nodes[0], extref);
-		return 0;
-	}
-
-	return -ENOENT;
 }
 
 static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,