ocfs2: Make ocfs2_extent_tree the first-class representation of a tree.

We now have three different kinds of extent trees in ocfs2: inode data
(dinode), extended attributes (xattr_tree), and extended attribute
values (xattr_value).  There is a nice abstraction for them,
ocfs2_extent_tree, but it is hidden in alloc.c.  All the calling
functions have to pick amongst a varied API and pass in type bits and
often extraneous pointers.

A better way is to make ocfs2_extent_tree a first-class object.
Everyone converts their object to an ocfs2_extent_tree() via the
ocfs2_get_*_extent_tree() calls, then uses the ocfs2_extent_tree for all
tree calls to alloc.c.

This simplifies a lot of callers, making for readability.  It also
provides an easy way to add additional extent tree types, as they only
need to be defined in alloc.c with a ocfs2_get_<new>_extent_tree()
function.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

8 files changed, 240 insertions, 332 deletions

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index ce54730e18f..786a8298262 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -49,20 +49,6 @@
 
 #include "buffer_head_io.h"
 
-/*
- * ocfs2_extent_tree and ocfs2_extent_tree_operations are used to abstract
- * the b-tree operations in ocfs2. Now all the b-tree operations are not
- * limited to ocfs2_dinode only. Any data which need to allocate clusters
- * to store can use b-tree. And it only needs to implement its ocfs2_extent_tree
- * and operation.
- *
- * ocfs2_extent_tree contains info for the root of the b-tree, it must have a
- * root ocfs2_extent_list and a root_bh so that they can be used in the b-tree
- * functions.
- * ocfs2_extent_tree_operations abstract the normal operations we do for
- * the root of extent b-tree.
- */
-struct ocfs2_extent_tree;
 
 struct ocfs2_extent_tree_operations {
 	void (*eo_set_last_eb_blk)(struct ocfs2_extent_tree *et,
@@ -83,28 +69,38 @@ struct ocfs2_extent_tree_operations {
 					  struct ocfs2_extent_tree *et);
 };
 
-struct ocfs2_extent_tree {
-	enum ocfs2_extent_tree_type		et_type;
-	struct ocfs2_extent_tree_operations	*et_ops;
-	struct buffer_head			*et_root_bh;
-	struct ocfs2_extent_list		*et_root_el;
-	void					*et_object;
-	unsigned int				et_max_leaf_clusters;
-};
 
-static void ocfs2_dinode_fill_root_el(struct ocfs2_extent_tree *et)
-{
-	struct ocfs2_dinode *di = et->et_object;
-
-	et->et_root_el = &di->id2.i_list;
-}
+/*
+ * Pre-declare ocfs2_dinode_et_ops so we can use it as a sanity check
+ * in the methods.
+ */
+static u64 ocfs2_dinode_get_last_eb_blk(struct ocfs2_extent_tree *et);
+static void ocfs2_dinode_set_last_eb_blk(struct ocfs2_extent_tree *et,
+					 u64 blkno);
+static void ocfs2_dinode_update_clusters(struct inode *inode,
+					 struct ocfs2_extent_tree *et,
+					 u32 clusters);
+static int ocfs2_dinode_insert_check(struct inode *inode,
+				     struct ocfs2_extent_tree *et,
+				     struct ocfs2_extent_rec *rec);
+static int ocfs2_dinode_sanity_check(struct inode *inode,
+				     struct ocfs2_extent_tree *et);
+static void ocfs2_dinode_fill_root_el(struct ocfs2_extent_tree *et);
+static struct ocfs2_extent_tree_operations ocfs2_dinode_et_ops = {
+	.eo_set_last_eb_blk	= ocfs2_dinode_set_last_eb_blk,
+	.eo_get_last_eb_blk	= ocfs2_dinode_get_last_eb_blk,
+	.eo_update_clusters	= ocfs2_dinode_update_clusters,
+	.eo_insert_check	= ocfs2_dinode_insert_check,
+	.eo_sanity_check	= ocfs2_dinode_sanity_check,
+	.eo_fill_root_el	= ocfs2_dinode_fill_root_el,
+};
 
 static void ocfs2_dinode_set_last_eb_blk(struct ocfs2_extent_tree *et,
 					 u64 blkno)
 {
 	struct ocfs2_dinode *di = et->et_object;
 
-	BUG_ON(et->et_type != OCFS2_DINODE_EXTENT);
+	BUG_ON(et->et_ops != &ocfs2_dinode_et_ops);
 	di->i_last_eb_blk = cpu_to_le64(blkno);
 }
 
@@ -112,7 +108,7 @@ static u64 ocfs2_dinode_get_last_eb_blk(struct ocfs2_extent_tree *et)
 {
 	struct ocfs2_dinode *di = et->et_object;
 
-	BUG_ON(et->et_type != OCFS2_DINODE_EXTENT);
+	BUG_ON(et->et_ops != &ocfs2_dinode_et_ops);
 	return le64_to_cpu(di->i_last_eb_blk);
 }
 
@@ -153,7 +149,7 @@ static int ocfs2_dinode_sanity_check(struct inode *inode,
 	int ret = 0;
 	struct ocfs2_dinode *di;
 
-	BUG_ON(et->et_type != OCFS2_DINODE_EXTENT);
+	BUG_ON(et->et_ops != &ocfs2_dinode_et_ops);
 
 	di = et->et_object;
 	if (!OCFS2_IS_VALID_DINODE(di)) {
@@ -166,14 +162,13 @@ static int ocfs2_dinode_sanity_check(struct inode *inode,
 	return ret;
 }
 
-static struct ocfs2_extent_tree_operations ocfs2_dinode_et_ops = {
-	.eo_set_last_eb_blk	= ocfs2_dinode_set_last_eb_blk,
-	.eo_get_last_eb_blk	= ocfs2_dinode_get_last_eb_blk,
-	.eo_update_clusters	= ocfs2_dinode_update_clusters,
-	.eo_insert_check	= ocfs2_dinode_insert_check,
-	.eo_sanity_check	= ocfs2_dinode_sanity_check,
-	.eo_fill_root_el	= ocfs2_dinode_fill_root_el,
-};
+static void ocfs2_dinode_fill_root_el(struct ocfs2_extent_tree *et)
+{
+	struct ocfs2_dinode *di = et->et_object;
+
+	et->et_root_el = &di->id2.i_list;
+}
+
 
 static void ocfs2_xattr_value_fill_root_el(struct ocfs2_extent_tree *et)
 {
@@ -269,10 +264,8 @@ static void __ocfs2_get_extent_tree(struct ocfs2_extent_tree *et,
 				    struct inode *inode,
 				    struct buffer_head *bh,
 				    void *obj,
-				    enum ocfs2_extent_tree_type et_type,
 				    struct ocfs2_extent_tree_operations *ops)
 {
-	et->et_type = et_type;
 	et->et_ops = ops;
 	get_bh(bh);
 	et->et_root_bh = bh;
@@ -287,50 +280,31 @@ static void __ocfs2_get_extent_tree(struct ocfs2_extent_tree *et,
 		et->et_ops->eo_fill_max_leaf_clusters(inode, et);
 }
 
-static void ocfs2_get_dinode_extent_tree(struct ocfs2_extent_tree *et,
-					 struct inode *inode,
-					 struct buffer_head *bh)
+void ocfs2_get_dinode_extent_tree(struct ocfs2_extent_tree *et,
+				  struct inode *inode,
+				  struct buffer_head *bh)
 {
-	__ocfs2_get_extent_tree(et, inode, bh, NULL, OCFS2_DINODE_EXTENT,
-				&ocfs2_dinode_et_ops);
+	__ocfs2_get_extent_tree(et, inode, bh, NULL, &ocfs2_dinode_et_ops);
 }
 
-static void ocfs2_get_xattr_tree_extent_tree(struct ocfs2_extent_tree *et,
-					     struct inode *inode,
-					     struct buffer_head *bh)
+void ocfs2_get_xattr_tree_extent_tree(struct ocfs2_extent_tree *et,
+				      struct inode *inode,
+				      struct buffer_head *bh)
 {
 	__ocfs2_get_extent_tree(et, inode, bh, NULL,
-				OCFS2_XATTR_TREE_EXTENT,
 				&ocfs2_xattr_tree_et_ops);
 }
 
-static void ocfs2_get_xattr_value_extent_tree(struct ocfs2_extent_tree *et,
-					     struct inode *inode,
-					     struct buffer_head *bh,
-					     struct ocfs2_xattr_value_root *xv)
+void ocfs2_get_xattr_value_extent_tree(struct ocfs2_extent_tree *et,
+				       struct inode *inode,
+				       struct buffer_head *bh,
+				       struct ocfs2_xattr_value_root *xv)
 {
 	__ocfs2_get_extent_tree(et, inode, bh, xv,
-				OCFS2_XATTR_VALUE_EXTENT,
 				&ocfs2_xattr_value_et_ops);
 }
 
-static void ocfs2_get_extent_tree(struct ocfs2_extent_tree *et,
-				  struct inode *inode,
-				  struct buffer_head *bh,
-				  enum ocfs2_extent_tree_type et_type,
-				  void *obj)
-{
-	if (et_type == OCFS2_DINODE_EXTENT)
-		ocfs2_get_dinode_extent_tree(et, inode, bh);
-	else if (et_type == OCFS2_XATTR_VALUE_EXTENT)
-		ocfs2_get_xattr_tree_extent_tree(et, inode, bh);
-	else if (et_type == OCFS2_XATTR_TREE_EXTENT)
-		ocfs2_get_xattr_value_extent_tree(et, inode, bh, obj);
-	else
-		BUG();
-}
-
-static void ocfs2_put_extent_tree(struct ocfs2_extent_tree *et)
+void ocfs2_put_extent_tree(struct ocfs2_extent_tree *et)
 {
 	brelse(et->et_root_bh);
 }
@@ -682,22 +656,18 @@ struct ocfs2_merge_ctxt {
  */
 int ocfs2_num_free_extents(struct ocfs2_super *osb,
 			   struct inode *inode,
-			   struct buffer_head *root_bh,
-			   enum ocfs2_extent_tree_type type,
-			   void *obj)
+			   struct ocfs2_extent_tree *et)
 {
 	int retval;
 	struct ocfs2_extent_list *el = NULL;
 	struct ocfs2_extent_block *eb;
 	struct buffer_head *eb_bh = NULL;
 	u64 last_eb_blk = 0;
-	struct ocfs2_extent_tree et;
 
 	mlog_entry_void();
 
-	ocfs2_get_extent_tree(&et, inode, root_bh, type, obj);
-	el = et.et_root_el;
-	last_eb_blk = ocfs2_et_get_last_eb_blk(&et);
+	el = et->et_root_el;
+	last_eb_blk = ocfs2_et_get_last_eb_blk(et);
 
 	if (last_eb_blk) {
 		retval = ocfs2_read_block(osb, last_eb_blk,
@@ -717,7 +687,6 @@ bail:
 	if (eb_bh)
 		brelse(eb_bh);
 
-	ocfs2_put_extent_tree(&et);
 	mlog_exit(retval);
 	return retval;
 }
@@ -4406,16 +4375,15 @@ out:
  *
  * The caller needs to update fe->i_clusters
  */
-static int ocfs2_insert_extent(struct ocfs2_super *osb,
-			       handle_t *handle,
-			       struct inode *inode,
-			       struct buffer_head *root_bh,
-			       u32 cpos,
-			       u64 start_blk,
-			       u32 new_clusters,
-			       u8 flags,
-			       struct ocfs2_alloc_context *meta_ac,
-			       struct ocfs2_extent_tree *et)
+int ocfs2_insert_extent(struct ocfs2_super *osb,
+			handle_t *handle,
+			struct inode *inode,
+			struct ocfs2_extent_tree *et,
+			u32 cpos,
+			u64 start_blk,
+			u32 new_clusters,
+			u8 flags,
+			struct ocfs2_alloc_context *meta_ac)
 {
 	int status;
 	int uninitialized_var(free_records);
@@ -4464,7 +4432,7 @@ static int ocfs2_insert_extent(struct ocfs2_super *osb,
 	status = ocfs2_do_insert_extent(inode, handle, et, &rec, &insert);
 	if (status < 0)
 		mlog_errno(status);
-	else if (et->et_type == OCFS2_DINODE_EXTENT)
+	else if (et->et_ops == &ocfs2_dinode_et_ops)
 		ocfs2_extent_map_insert_rec(inode, &rec);
 
 bail:
@@ -4475,77 +4443,10 @@ bail:
 	return status;
 }
 
-int ocfs2_dinode_insert_extent(struct ocfs2_super *osb,
-			       handle_t *handle,
-			       struct inode *inode,
-			       struct buffer_head *root_bh,
-			       u32 cpos,
-			       u64 start_blk,
-			       u32 new_clusters,
-			       u8 flags,
-			       struct ocfs2_alloc_context *meta_ac)
-{
-	int status;
-	struct ocfs2_extent_tree et;
-
-	ocfs2_get_dinode_extent_tree(&et, inode, root_bh);
-	status = ocfs2_insert_extent(osb, handle, inode, root_bh,
-				     cpos, start_blk, new_clusters,
-				     flags, meta_ac, &et);
-	ocfs2_put_extent_tree(&et);
-
-	return status;
-}
-
-int ocfs2_xattr_value_insert_extent(struct ocfs2_super *osb,
-				    handle_t *handle,
-				    struct inode *inode,
-				    struct buffer_head *root_bh,
-				    u32 cpos,
-				    u64 start_blk,
-				    u32 new_clusters,
-				    u8 flags,
-				    struct ocfs2_alloc_context *meta_ac,
-				    struct ocfs2_xattr_value_root *xv)
-{
-	int status;
-	struct ocfs2_extent_tree et;
-
-	ocfs2_get_xattr_value_extent_tree(&et, inode, root_bh, xv);
-	status = ocfs2_insert_extent(osb, handle, inode, root_bh,
-				     cpos, start_blk, new_clusters,
-				     flags, meta_ac, &et);
-	ocfs2_put_extent_tree(&et);
-
-	return status;
-}
-
-int ocfs2_xattr_tree_insert_extent(struct ocfs2_super *osb,
-				   handle_t *handle,
-				   struct inode *inode,
-				   struct buffer_head *root_bh,
-				   u32 cpos,
-				   u64 start_blk,
-				   u32 new_clusters,
-				   u8 flags,
-				   struct ocfs2_alloc_context *meta_ac)
-{
-	int status;
-	struct ocfs2_extent_tree et;
-
-	ocfs2_get_xattr_tree_extent_tree(&et, inode, root_bh);
-	status = ocfs2_insert_extent(osb, handle, inode, root_bh,
-				     cpos, start_blk, new_clusters,
-				     flags, meta_ac, &et);
-	ocfs2_put_extent_tree(&et);
-
-	return status;
-}
-
 /*
  * Allcate and add clusters into the extent b-tree.
  * The new clusters(clusters_to_add) will be inserted at logical_offset.
- * The extent b-tree's root is root_el and it should be in root_bh, and
+ * The extent b-tree's root is specified by et, and
  * it is not limited to the file storage. Any extent tree can use this
  * function if it implements the proper ocfs2_extent_tree.
  */
@@ -4554,14 +4455,11 @@ int ocfs2_add_clusters_in_btree(struct ocfs2_super *osb,
 				u32 *logical_offset,
 				u32 clusters_to_add,
 				int mark_unwritten,
-				struct buffer_head *root_bh,
-				struct ocfs2_extent_list *root_el,
+				struct ocfs2_extent_tree *et,
 				handle_t *handle,
 				struct ocfs2_alloc_context *data_ac,
 				struct ocfs2_alloc_context *meta_ac,
-				enum ocfs2_alloc_restarted *reason_ret,
-				enum ocfs2_extent_tree_type type,
-				void *obj)
+				enum ocfs2_alloc_restarted *reason_ret)
 {
 	int status = 0;
 	int free_extents;
@@ -4575,8 +4473,7 @@ int ocfs2_add_clusters_in_btree(struct ocfs2_super *osb,
 	if (mark_unwritten)
 		flags = OCFS2_EXT_UNWRITTEN;
 
-	free_extents = ocfs2_num_free_extents(osb, inode, root_bh, type,
-					      obj);
+	free_extents = ocfs2_num_free_extents(osb, inode, et);
 	if (free_extents < 0) {
 		status = free_extents;
 		mlog_errno(status);
@@ -4595,7 +4492,7 @@ int ocfs2_add_clusters_in_btree(struct ocfs2_super *osb,
 		goto leave;
 	} else if ((!free_extents)
 		   && (ocfs2_alloc_context_bits_left(meta_ac)
-		       < ocfs2_extend_meta_needed(root_el))) {
+		       < ocfs2_extend_meta_needed(et->et_root_el))) {
 		mlog(0, "filesystem is really fragmented...\n");
 		status = -EAGAIN;
 		reason = RESTART_META;
@@ -4613,7 +4510,7 @@ int ocfs2_add_clusters_in_btree(struct ocfs2_super *osb,
 	BUG_ON(num_bits > clusters_to_add);
 
 	/* reserve our write early -- insert_extent may update the inode */
-	status = ocfs2_journal_access(handle, inode, root_bh,
+	status = ocfs2_journal_access(handle, inode, et->et_root_bh,
 				      OCFS2_JOURNAL_ACCESS_WRITE);
 	if (status < 0) {
 		mlog_errno(status);
@@ -4623,28 +4520,15 @@ int ocfs2_add_clusters_in_btree(struct ocfs2_super *osb,
 	block = ocfs2_clusters_to_blocks(osb->sb, bit_off);
 	mlog(0, "Allocating %u clusters at block %u for inode %llu\n",
 	     num_bits, bit_off, (unsigned long long)OCFS2_I(inode)->ip_blkno);
-	if (type == OCFS2_DINODE_EXTENT)
-		status = ocfs2_dinode_insert_extent(osb, handle, inode, root_bh,
-						    *logical_offset, block,
-						    num_bits, flags, meta_ac);
-	else if (type == OCFS2_XATTR_TREE_EXTENT)
-		status = ocfs2_xattr_tree_insert_extent(osb, handle,
-							inode, root_bh,
-							*logical_offset,
-							block, num_bits, flags,
-							meta_ac);
-	else
-		status = ocfs2_xattr_value_insert_extent(osb, handle,
-							 inode, root_bh,
-							 *logical_offset,
-							 block, num_bits, flags,
-							 meta_ac, obj);
+	status = ocfs2_insert_extent(osb, handle, inode, et,
+				     *logical_offset, block,
+				     num_bits, flags, meta_ac);
 	if (status < 0) {
 		mlog_errno(status);
 		goto leave;
 	}
 
-	status = ocfs2_journal_dirty(handle, root_bh);
+	status = ocfs2_journal_dirty(handle, et->et_root_bh);
 	if (status < 0) {
 		mlog_errno(status);
 		goto leave;
@@ -4915,25 +4799,21 @@ out:
  *
  * The caller is responsible for passing down meta_ac if we'll need it.
  */
-int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *root_bh,
+int ocfs2_mark_extent_written(struct inode *inode,
+			      struct ocfs2_extent_tree *et,
 			      handle_t *handle, u32 cpos, u32 len, u32 phys,
 			      struct ocfs2_alloc_context *meta_ac,
-			      struct ocfs2_cached_dealloc_ctxt *dealloc,
-			      enum ocfs2_extent_tree_type et_type,
-			      void *obj)
+			      struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
 	int ret, index;
 	u64 start_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys);
 	struct ocfs2_extent_rec split_rec;
 	struct ocfs2_path *left_path = NULL;
 	struct ocfs2_extent_list *el;
-	struct ocfs2_extent_tree et;
 
 	mlog(0, "Inode %lu cpos %u, len %u, phys %u (%llu)\n",
 	     inode->i_ino, cpos, len, phys, (unsigned long long)start_blkno);
 
-	ocfs2_get_extent_tree(&et, inode, root_bh, et_type, obj);
-
 	if (!ocfs2_writes_unwritten_extents(OCFS2_SB(inode->i_sb))) {
 		ocfs2_error(inode->i_sb, "Inode %llu has unwritten extents "
 			    "that are being written to, but the feature bit "
@@ -4946,11 +4826,14 @@ int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *root_bh,
 	/*
 	 * XXX: This should be fixed up so that we just re-insert the
 	 * next extent records.
+	 *
+	 * XXX: This is a hack on the extent tree, maybe it should be
+	 * an op?
 	 */
-	if (et_type == OCFS2_DINODE_EXTENT)
+	if (et->et_ops == &ocfs2_dinode_et_ops)
 		ocfs2_extent_map_trunc(inode, 0);
 
-	left_path = ocfs2_new_path(et.et_root_bh, et.et_root_el);
+	left_path = ocfs2_new_path(et->et_root_bh, et->et_root_el);
 	if (!left_path) {
 		ret = -ENOMEM;
 		mlog_errno(ret);
@@ -4981,7 +4864,7 @@ int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *root_bh,
 	split_rec.e_flags = path_leaf_el(left_path)->l_recs[index].e_flags;
 	split_rec.e_flags &= ~OCFS2_EXT_UNWRITTEN;
 
-	ret = __ocfs2_mark_extent_written(inode, &et, handle, left_path,
+	ret = __ocfs2_mark_extent_written(inode, et, handle, left_path,
 					  index, &split_rec, meta_ac,
 					  dealloc);
 	if (ret)
@@ -4989,7 +4872,6 @@ int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *root_bh,
 
 out:
 	ocfs2_free_path(left_path);
-	ocfs2_put_extent_tree(&et);
 	return ret;
 }
 
@@ -5219,25 +5101,21 @@ out:
 	return ret;
 }
 
-int ocfs2_remove_extent(struct inode *inode, struct buffer_head *root_bh,
+int ocfs2_remove_extent(struct inode *inode,
+			struct ocfs2_extent_tree *et,
 			u32 cpos, u32 len, handle_t *handle,
 			struct ocfs2_alloc_context *meta_ac,
-			struct ocfs2_cached_dealloc_ctxt *dealloc,
-			enum ocfs2_extent_tree_type et_type,
-			void *obj)
+			struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
 	int ret, index;
 	u32 rec_range, trunc_range;
 	struct ocfs2_extent_rec *rec;
 	struct ocfs2_extent_list *el;
 	struct ocfs2_path *path = NULL;
-	struct ocfs2_extent_tree et;
-
-	ocfs2_get_extent_tree(&et, inode, root_bh, et_type, obj);
 
 	ocfs2_extent_map_trunc(inode, 0);
 
-	path = ocfs2_new_path(et.et_root_bh, et.et_root_el);
+	path = ocfs2_new_path(et->et_root_bh, et->et_root_el);
 	if (!path) {
 		ret = -ENOMEM;
 		mlog_errno(ret);
@@ -5290,13 +5168,13 @@ int ocfs2_remove_extent(struct inode *inode, struct buffer_head *root_bh,
 
 	if (le32_to_cpu(rec->e_cpos) == cpos || rec_range == trunc_range) {
 		ret = ocfs2_truncate_rec(inode, handle, path, index, dealloc,
-					 cpos, len, &et);
+					 cpos, len, et);
 		if (ret) {
 			mlog_errno(ret);
 			goto out;
 		}
 	} else {
-		ret = ocfs2_split_tree(inode, &et, handle, path, index,
+		ret = ocfs2_split_tree(inode, et, handle, path, index,
 				       trunc_range, meta_ac);
 		if (ret) {
 			mlog_errno(ret);
@@ -5345,7 +5223,7 @@ int ocfs2_remove_extent(struct inode *inode, struct buffer_head *root_bh,
 		}
 
 		ret = ocfs2_truncate_rec(inode, handle, path, index, dealloc,
-					 cpos, len, &et);
+					 cpos, len, et);
 		if (ret) {
 			mlog_errno(ret);
 			goto out;
@@ -5354,7 +5232,6 @@ int ocfs2_remove_extent(struct inode *inode, struct buffer_head *root_bh,
 
 out:
 	ocfs2_free_path(path);
-	ocfs2_put_extent_tree(&et);
 	return ret;
 }
 
@@ -6773,6 +6650,7 @@ int ocfs2_convert_inline_data_to_extents(struct inode *inode,
 	struct ocfs2_alloc_context *data_ac = NULL;
 	struct page **pages = NULL;
 	loff_t end = osb->s_clustersize;
+	struct ocfs2_extent_tree et;
 
 	has_data = i_size_read(inode) ? 1 : 0;
 
@@ -6872,8 +6750,10 @@ int ocfs2_convert_inline_data_to_extents(struct inode *inode,
 		 * this proves to be false, we could always re-build
 		 * the in-inode data from our pages.
 		 */
-		ret = ocfs2_dinode_insert_extent(osb, handle, inode, di_bh,
-						 0, block, 1, 0, NULL);
+		ocfs2_get_dinode_extent_tree(&et, inode, di_bh);
+		ret = ocfs2_insert_extent(osb, handle, inode, &et,
+					  0, block, 1, 0, NULL);
+		ocfs2_put_extent_tree(&et);
 		if (ret) {
 			mlog_errno(ret);
 			goto out_commit;
diff --git a/fs/ocfs2/alloc.h b/fs/ocfs2/alloc.h
index 5cc9a83cf1a..35ad07f9610 100644
--- a/fs/ocfs2/alloc.h
+++ b/fs/ocfs2/alloc.h
@@ -26,46 +26,66 @@
 #ifndef OCFS2_ALLOC_H
 #define OCFS2_ALLOC_H
 
-enum ocfs2_extent_tree_type {
-	OCFS2_DINODE_EXTENT = 0,
-	OCFS2_XATTR_VALUE_EXTENT,
-	OCFS2_XATTR_TREE_EXTENT,
-};
 
 /*
  * For xattr tree leaf, we limit the leaf byte size to be 64K.
  */
 #define OCFS2_MAX_XATTR_TREE_LEAF_SIZE 65536
 
+/*
+ * ocfs2_extent_tree and ocfs2_extent_tree_operations are used to abstract
+ * the b-tree operations in ocfs2. Now all the b-tree operations are not
+ * limited to ocfs2_dinode only. Any data which need to allocate clusters
+ * to store can use b-tree. And it only needs to implement its ocfs2_extent_tree
+ * and operation.
+ *
+ * ocfs2_extent_tree becomes the first-class object for extent tree
+ * manipulation.  Callers of the alloc.c code need to fill it via one of
+ * the ocfs2_get_*_extent_tree() operations below.
+ *
+ * ocfs2_extent_tree contains info for the root of the b-tree, it must have a
+ * root ocfs2_extent_list and a root_bh so that they can be used in the b-tree
+ * functions.
+ * ocfs2_extent_tree_operations abstract the normal operations we do for
+ * the root of extent b-tree.
+ */
+struct ocfs2_extent_tree_operations;
+struct ocfs2_extent_tree {
+	struct ocfs2_extent_tree_operations	*et_ops;
+	struct buffer_head			*et_root_bh;
+	struct ocfs2_extent_list		*et_root_el;
+	void					*et_object;
+	unsigned int				et_max_leaf_clusters;
+};
+
+/*
+ * ocfs2_*_get_extent_tree() will fill an ocfs2_extent_tree from the
+ * specified object buffer.  The bh is referenced until
+ * ocfs2_put_extent_tree().
+ */
+void ocfs2_get_dinode_extent_tree(struct ocfs2_extent_tree *et,
+				  struct inode *inode,
+				  struct buffer_head *bh);
+void ocfs2_get_xattr_tree_extent_tree(struct ocfs2_extent_tree *et,
+				      struct inode *inode,
+				      struct buffer_head *bh);
+void ocfs2_get_xattr_value_extent_tree(struct ocfs2_extent_tree *et,
+				       struct inode *inode,
+				       struct buffer_head *bh,
+				       struct ocfs2_xattr_value_root *xv);
+void ocfs2_put_extent_tree(struct ocfs2_extent_tree *et);
+
 struct ocfs2_alloc_context;
-int ocfs2_dinode_insert_extent(struct ocfs2_super *osb,
-			       handle_t *handle,
-			       struct inode *inode,
-			       struct buffer_head *root_bh,
-			       u32 cpos,
-			       u64 start_blk,
-			       u32 new_clusters,
-			       u8 flags,
-			       struct ocfs2_alloc_context *meta_ac);
-int ocfs2_xattr_value_insert_extent(struct ocfs2_super *osb,
-				    handle_t *handle,
-				    struct inode *inode,
-				    struct buffer_head *root_bh,
-				    u32 cpos,
-				    u64 start_blk,
-				    u32 new_clusters,
-				    u8 flags,
-				    struct ocfs2_alloc_context *meta_ac,
-				    struct ocfs2_xattr_value_root *xv);
-int ocfs2_xattr_tree_insert_extent(struct ocfs2_super *osb,
-				   handle_t *handle,
-				   struct inode *inode,
-				   struct buffer_head *root_bh,
-				   u32 cpos,
-				   u64 start_blk,
-				   u32 new_clusters,
-				   u8 flags,
-				   struct ocfs2_alloc_context *meta_ac);
+int ocfs2_insert_extent(struct ocfs2_super *osb,
+			handle_t *handle,
+			struct inode *inode,
+			struct ocfs2_extent_tree *et,
+			u32 cpos,
+			u64 start_blk,
+			u32 new_clusters,
+			u8 flags,
+			struct ocfs2_alloc_context *meta_ac);
+
 enum ocfs2_alloc_restarted {
 	RESTART_NONE = 0,
 	RESTART_TRANS,
@@ -76,32 +96,25 @@ int ocfs2_add_clusters_in_btree(struct ocfs2_super *osb,
 				u32 *logical_offset,
 				u32 clusters_to_add,
 				int mark_unwritten,
-				struct buffer_head *root_bh,
-				struct ocfs2_extent_list *root_el,
+				struct ocfs2_extent_tree *et,
 				handle_t *handle,
 				struct ocfs2_alloc_context *data_ac,
 				struct ocfs2_alloc_context *meta_ac,
-				enum ocfs2_alloc_restarted *reason_ret,
-				enum ocfs2_extent_tree_type type,
-				void *private);
+				enum ocfs2_alloc_restarted *reason_ret);
 struct ocfs2_cached_dealloc_ctxt;
-int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *root_bh,
+int ocfs2_mark_extent_written(struct inode *inode,
+			      struct ocfs2_extent_tree *et,
 			      handle_t *handle, u32 cpos, u32 len, u32 phys,
 			      struct ocfs2_alloc_context *meta_ac,
-			      struct ocfs2_cached_dealloc_ctxt *dealloc,
-			      enum ocfs2_extent_tree_type et_type,
-			      void *private);
-int ocfs2_remove_extent(struct inode *inode, struct buffer_head *root_bh,
+			      struct ocfs2_cached_dealloc_ctxt *dealloc);
+int ocfs2_remove_extent(struct inode *inode,
+			struct ocfs2_extent_tree *et,
 			u32 cpos, u32 len, handle_t *handle,
 			struct ocfs2_alloc_context *meta_ac,
-			struct ocfs2_cached_dealloc_ctxt *dealloc,
-			enum ocfs2_extent_tree_type et_type,
-			void *private);
+			struct ocfs2_cached_dealloc_ctxt *dealloc);
 int ocfs2_num_free_extents(struct ocfs2_super *osb,
 			   struct inode *inode,
-			   struct buffer_head *root_bh,
-			   enum ocfs2_extent_tree_type et_type,
-			   void *private);
+			   struct ocfs2_extent_tree *et);
 
 /*
  * how many new metadata chunks would an allocation need at maximum?
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 530b1ff599c..ed937fa9e4e 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -1242,6 +1242,7 @@ static int ocfs2_write_cluster(struct address_space *mapping,
 	int ret, i, new, should_zero = 0;
 	u64 v_blkno, p_blkno;
 	struct inode *inode = mapping->host;
+	struct ocfs2_extent_tree et;
 
 	new = phys == 0 ? 1 : 0;
 	if (new || unwritten)
@@ -1276,10 +1277,11 @@ static int ocfs2_write_cluster(struct address_space *mapping,
 			goto out;
 		}
 	} else if (unwritten) {
-		ret = ocfs2_mark_extent_written(inode, wc->w_di_bh,
+		ocfs2_get_dinode_extent_tree(&et, inode, wc->w_di_bh);
+		ret = ocfs2_mark_extent_written(inode, &et,
 						wc->w_handle, cpos, 1, phys,
-						meta_ac, &wc->w_dealloc,
-						OCFS2_DINODE_EXTENT, NULL);
+						meta_ac, &wc->w_dealloc);
+		ocfs2_put_extent_tree(&et);
 		if (ret < 0) {
 			mlog_errno(ret);
 			goto out;
@@ -1666,6 +1668,7 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
 	struct ocfs2_alloc_context *data_ac = NULL;
 	struct ocfs2_alloc_context *meta_ac = NULL;
 	handle_t *handle;
+	struct ocfs2_extent_tree et;
 
 	ret = ocfs2_alloc_write_ctxt(&wc, osb, pos, len, di_bh);
 	if (ret) {
@@ -1719,10 +1722,11 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
 		     (long long)i_size_read(inode), le32_to_cpu(di->i_clusters),
 		     clusters_to_alloc, extents_to_split);
 
-		ret = ocfs2_lock_allocators(inode, wc->w_di_bh, &di->id2.i_list,
+		ocfs2_get_dinode_extent_tree(&et, inode, wc->w_di_bh);
+		ret = ocfs2_lock_allocators(inode, &et,
 					    clusters_to_alloc, extents_to_split,
-					    &data_ac, &meta_ac,
-					    OCFS2_DINODE_EXTENT, NULL);
+					    &data_ac, &meta_ac);
+		ocfs2_put_extent_tree(&et);
 		if (ret) {
 			mlog_errno(ret);
 			goto out;
diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index 5426a02c12b..2cdc5539034 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -1192,6 +1192,9 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 	struct buffer_head *dirdata_bh = NULL;
 	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
 	handle_t *handle;
+	struct ocfs2_extent_tree et;
+
+	ocfs2_get_dinode_extent_tree(&et, dir, di_bh);
 
 	alloc = ocfs2_clusters_for_bytes(sb, bytes);
 
@@ -1305,8 +1308,8 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 	 * This should never fail as our extent list is empty and all
 	 * related blocks have been journaled already.
 	 */
-	ret = ocfs2_dinode_insert_extent(osb, handle, dir, di_bh, 0, blkno,
-					 len, 0, NULL);
+	ret = ocfs2_insert_extent(osb, handle, dir, &et, 0, blkno, len,
+				  0, NULL);
 	if (ret) {
 		mlog_errno(ret);
 		goto out_commit;
@@ -1337,8 +1340,8 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 		}
 		blkno = ocfs2_clusters_to_blocks(dir->i_sb, bit_off);
 
-		ret = ocfs2_dinode_insert_extent(osb, handle, dir, di_bh, 1,
-						 blkno, len, 0, NULL);
+		ret = ocfs2_insert_extent(osb, handle, dir, &et, 1,
+					  blkno, len, 0, NULL);
 		if (ret) {
 			mlog_errno(ret);
 			goto out_commit;
@@ -1360,6 +1363,7 @@ out:
 
 	brelse(dirdata_bh);
 
+	ocfs2_put_extent_tree(&et);
 	return ret;
 }
 
@@ -1437,6 +1441,7 @@ static int ocfs2_extend_dir(struct ocfs2_super *osb,
 	struct buffer_head *new_bh = NULL;
 	struct ocfs2_dir_entry * de;
 	struct super_block *sb = osb->sb;
+	struct ocfs2_extent_tree et;
 
 	mlog_entry_void();
 
@@ -1480,10 +1485,9 @@ static int ocfs2_extend_dir(struct ocfs2_super *osb,
 	spin_lock(&OCFS2_I(dir)->ip_lock);
 	if (dir_i_size == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters)) {
 		spin_unlock(&OCFS2_I(dir)->ip_lock);
-		num_free_extents = ocfs2_num_free_extents(osb, dir,
-							  parent_fe_bh,
-							  OCFS2_DINODE_EXTENT,
-							  NULL);
+		ocfs2_get_dinode_extent_tree(&et, dir, parent_fe_bh);
+		num_free_extents = ocfs2_num_free_extents(osb, dir, &et);
+		ocfs2_put_extent_tree(&et);
 		if (num_free_extents < 0) {
 			status = num_free_extents;
 			mlog_errno(status);
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index f4273c2c209..ca3d38addbb 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -509,14 +509,17 @@ int ocfs2_add_inode_data(struct ocfs2_super *osb,
 			 struct ocfs2_alloc_context *meta_ac,
 			 enum ocfs2_alloc_restarted *reason_ret)
 {
-	struct ocfs2_dinode *fe = (struct ocfs2_dinode *) fe_bh->b_data;
-	struct ocfs2_extent_list *el = &fe->id2.i_list;
+	int ret;
+	struct ocfs2_extent_tree et;
 
-	return ocfs2_add_clusters_in_btree(osb, inode, logical_offset,
+	ocfs2_get_dinode_extent_tree(&et, inode, fe_bh);
+	ret = ocfs2_add_clusters_in_btree(osb, inode, logical_offset,
 					   clusters_to_add, mark_unwritten,
-					   fe_bh, el, handle,
-					   data_ac, meta_ac, reason_ret,
-					   OCFS2_DINODE_EXTENT, NULL);
+					   &et, handle,
+					   data_ac, meta_ac, reason_ret);
+	ocfs2_put_extent_tree(&et);
+
+	return ret;
 }
 
 static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
@@ -533,6 +536,7 @@ static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
 	struct ocfs2_alloc_context *meta_ac = NULL;
 	enum ocfs2_alloc_restarted why;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct ocfs2_extent_tree et;
 
 	mlog_entry("(clusters_to_add = %u)\n", clusters_to_add);
 
@@ -564,9 +568,10 @@ restart_all:
 	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
 	     (long long)i_size_read(inode), le32_to_cpu(fe->i_clusters),
 	     clusters_to_add);
-	status = ocfs2_lock_allocators(inode, bh, &fe->id2.i_list,
-				       clusters_to_add, 0, &data_ac,
-				       &meta_ac, OCFS2_DINODE_EXTENT, NULL);
+	ocfs2_get_dinode_extent_tree(&et, inode, bh);
+	status = ocfs2_lock_allocators(inode, &et, clusters_to_add, 0,
+				       &data_ac, &meta_ac);
+	ocfs2_put_extent_tree(&et);
 	if (status) {
 		mlog_errno(status);
 		goto leave;
@@ -1236,11 +1241,13 @@ static int __ocfs2_remove_inode_range(struct inode *inode,
 	handle_t *handle;
 	struct ocfs2_alloc_context *meta_ac = NULL;
 	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+	struct ocfs2_extent_tree et;
+
+	ocfs2_get_dinode_extent_tree(&et, inode, di_bh);
 
-	ret = ocfs2_lock_allocators(inode, di_bh, &di->id2.i_list,
-				    0, 1, NULL, &meta_ac,
-				    OCFS2_DINODE_EXTENT, NULL);
+	ret = ocfs2_lock_allocators(inode, &et, 0, 1, NULL, &meta_ac);
 	if (ret) {
+		ocfs2_put_extent_tree(&et);
 		mlog_errno(ret);
 		return ret;
 	}
@@ -1269,8 +1276,8 @@ static int __ocfs2_remove_inode_range(struct inode *inode,
 		goto out;
 	}
 
-	ret = ocfs2_remove_extent(inode, di_bh, cpos, len, handle, meta_ac,
-				  dealloc, OCFS2_DINODE_EXTENT, NULL);
+	ret = ocfs2_remove_extent(inode, &et, cpos, len, handle, meta_ac,
+				  dealloc);
 	if (ret) {
 		mlog_errno(ret);
 		goto out_commit;
@@ -1297,6 +1304,7 @@ out:
 	if (meta_ac)
 		ocfs2_free_alloc_context(meta_ac);
 
+	ocfs2_put_extent_tree(&et);
 	return ret;
 }
 
diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index f1871ca8381..8d3947e94a2 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -1914,12 +1914,11 @@ static inline void ocfs2_debug_suballoc_inode(struct ocfs2_dinode *fe)
  * File systems which don't support holes call this from
  * ocfs2_extend_allocation().
  */
-int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *root_bh,
-			  struct ocfs2_extent_list *root_el,
+int ocfs2_lock_allocators(struct inode *inode,
+			  struct ocfs2_extent_tree *et,
 			  u32 clusters_to_add, u32 extents_to_split,
 			  struct ocfs2_alloc_context **data_ac,
-			  struct ocfs2_alloc_context **meta_ac,
-			  enum ocfs2_extent_tree_type type, void *private)
+			  struct ocfs2_alloc_context **meta_ac)
 {
 	int ret = 0, num_free_extents;
 	unsigned int max_recs_needed = clusters_to_add + 2 * extents_to_split;
@@ -1931,8 +1930,7 @@ int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *root_bh,
 
 	BUG_ON(clusters_to_add != 0 && data_ac == NULL);
 
-	num_free_extents = ocfs2_num_free_extents(osb, inode, root_bh,
-						  type, private);
+	num_free_extents = ocfs2_num_free_extents(osb, inode, et);
 	if (num_free_extents < 0) {
 		ret = num_free_extents;
 		mlog_errno(ret);
@@ -1954,7 +1952,7 @@ int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *root_bh,
 	 */
 	if (!num_free_extents ||
 	    (ocfs2_sparse_alloc(osb) && num_free_extents < max_recs_needed)) {
-		ret = ocfs2_reserve_new_metadata(osb, root_el, meta_ac);
+		ret = ocfs2_reserve_new_metadata(osb, et->et_root_el, meta_ac);
 		if (ret < 0) {
 			if (ret != -ENOSPC)
 				mlog_errno(ret);
diff --git a/fs/ocfs2/suballoc.h b/fs/ocfs2/suballoc.h
index 028fd633b44..dd0963695ed 100644
--- a/fs/ocfs2/suballoc.h
+++ b/fs/ocfs2/suballoc.h
@@ -165,10 +165,8 @@ u64 ocfs2_which_cluster_group(struct inode *inode, u32 cluster);
 int ocfs2_check_group_descriptor(struct super_block *sb,
 				 struct ocfs2_dinode *di,
 				 struct ocfs2_group_desc *gd);
-int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *root_bh,
-			  struct ocfs2_extent_list *root_el,
+int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_extent_tree *et,
 			  u32 clusters_to_add, u32 extents_to_split,
 			  struct ocfs2_alloc_context **data_ac,
-			  struct ocfs2_alloc_context **meta_ac,
-			  enum ocfs2_extent_tree_type type, void *private);
+			  struct ocfs2_alloc_context **meta_ac);
 #endif /* _CHAINALLOC_H_ */
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 1b349c7367a..9c3d4dc3e2e 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -206,22 +206,24 @@ static int ocfs2_xattr_extend_allocation(struct inode *inode,
 	struct ocfs2_alloc_context *meta_ac = NULL;
 	enum ocfs2_alloc_restarted why;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
-	struct ocfs2_extent_list *root_el = &xv->xr_list;
 	u32 prev_clusters, logical_start = le32_to_cpu(xv->xr_clusters);
+	struct ocfs2_extent_tree et;
 
 	mlog(0, "(clusters_to_add for xattr= %u)\n", clusters_to_add);
 
+	ocfs2_get_xattr_value_extent_tree(&et, inode, xattr_bh, xv);
+
 restart_all:
 
-	status = ocfs2_lock_allocators(inode, xattr_bh, root_el,
-				       clusters_to_add, 0, &data_ac,
-				       &meta_ac, OCFS2_XATTR_VALUE_EXTENT, xv);
+	status = ocfs2_lock_allocators(inode, &et, clusters_to_add, 0,
+				       &data_ac, &meta_ac);
 	if (status) {
 		mlog_errno(status);
 		goto leave;
 	}
 
-	credits = ocfs2_calc_extend_credits(osb->sb, root_el, clusters_to_add);
+	credits = ocfs2_calc_extend_credits(osb->sb, et.et_root_el,
+					    clusters_to_add);
 	handle = ocfs2_start_trans(osb, credits);
 	if (IS_ERR(handle)) {
 		status = PTR_ERR(handle);
@@ -244,14 +246,11 @@ restarted_transaction:
 					     &logical_start,
 					     clusters_to_add,
 					     0,
-					     xattr_bh,
-					     root_el,
+					     &et,
 					     handle,
 					     data_ac,
 					     meta_ac,
-					     &why,
-					     OCFS2_XATTR_VALUE_EXTENT,
-					     xv);
+					     &why);
 	if ((status < 0) && (status != -EAGAIN)) {
 		if (status != -ENOSPC)
 			mlog_errno(status);
@@ -276,7 +275,7 @@ restarted_transaction:
 			mlog(0, "restarting transaction.\n");
 			/* TODO: This can be more intelligent. */
 			credits = ocfs2_calc_extend_credits(osb->sb,
-							    root_el,
+							    et.et_root_el,
 							    clusters_to_add);
 			status = ocfs2_extend_trans(handle, credits);
 			if (status < 0) {
@@ -308,6 +307,7 @@ leave:
 		goto restart_all;
 	}
 
+	ocfs2_put_extent_tree(&et);
 	return status;
 }
 
@@ -323,11 +323,13 @@ static int __ocfs2_remove_xattr_range(struct inode *inode,
 	struct inode *tl_inode = osb->osb_tl_inode;
 	handle_t *handle;
 	struct ocfs2_alloc_context *meta_ac = NULL;
+	struct ocfs2_extent_tree et;
+
+	ocfs2_get_xattr_value_extent_tree(&et, inode, root_bh, xv);
 
-	ret = ocfs2_lock_allocators(inode, root_bh, &xv->xr_list,
-				    0, 1, NULL, &meta_ac,
-				    OCFS2_XATTR_VALUE_EXTENT, xv);
+	ret = ocfs2_lock_allocators(inode, &et, 0, 1, NULL, &meta_ac);
 	if (ret) {
+		ocfs2_put_extent_tree(&et);
 		mlog_errno(ret);
 		return ret;
 	}
@@ -356,8 +358,8 @@ static int __ocfs2_remove_xattr_range(struct inode *inode,
 		goto out_commit;
 	}
 
-	ret = ocfs2_remove_extent(inode, root_bh, cpos, len, handle, meta_ac,
-				  dealloc, OCFS2_XATTR_VALUE_EXTENT, xv);
+	ret = ocfs2_remove_extent(inode, &et, cpos, len, handle, meta_ac,
+				  dealloc);
 	if (ret) {
 		mlog_errno(ret);
 		goto out_commit;
@@ -383,6 +385,7 @@ out:
 	if (meta_ac)
 		ocfs2_free_alloc_context(meta_ac);
 
+	ocfs2_put_extent_tree(&et);
 	return ret;
 }
 
@@ -3622,26 +3625,24 @@ static int ocfs2_add_new_xattr_cluster(struct inode *inode,
 	struct ocfs2_alloc_context *data_ac = NULL;
 	struct ocfs2_alloc_context *meta_ac = NULL;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
-	struct ocfs2_xattr_block *xb =
-			(struct ocfs2_xattr_block *)root_bh->b_data;
-	struct ocfs2_xattr_tree_root *xb_root = &xb->xb_attrs.xb_root;
-	struct ocfs2_extent_list *root_el = &xb_root->xt_list;
-	enum ocfs2_extent_tree_type type = OCFS2_XATTR_TREE_EXTENT;
+	struct ocfs2_extent_tree et;
 
 	mlog(0, "Add new xattr cluster for %llu, previous xattr hash = %u, "
 	     "previous xattr blkno = %llu\n",
 	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
 	     prev_cpos, prev_blkno);
 
-	ret = ocfs2_lock_allocators(inode, root_bh, root_el,
-				    clusters_to_add, 0, &data_ac,
-				    &meta_ac, type, NULL);
+	ocfs2_get_xattr_tree_extent_tree(&et, inode, root_bh);
+
+	ret = ocfs2_lock_allocators(inode, &et, clusters_to_add, 0,
+				    &data_ac, &meta_ac);
 	if (ret) {
 		mlog_errno(ret);
 		goto leave;
 	}
 
-	credits = ocfs2_calc_extend_credits(osb->sb, root_el, clusters_to_add);
+	credits = ocfs2_calc_extend_credits(osb->sb, et.et_root_el,
+					    clusters_to_add);
 	handle = ocfs2_start_trans(osb, credits);
 	if (IS_ERR(handle)) {
 		ret = PTR_ERR(handle);
@@ -3705,9 +3706,8 @@ static int ocfs2_add_new_xattr_cluster(struct inode *inode,
 
 	mlog(0, "Insert %u clusters at block %llu for xattr at %u\n",
 	     num_bits, block, v_start);
-	ret = ocfs2_xattr_tree_insert_extent(osb, handle, inode, root_bh,
-					     v_start, block, num_bits,
-					     0, meta_ac);
+	ret = ocfs2_insert_extent(osb, handle, inode, &et, v_start, block,
+				  num_bits, 0, meta_ac);
 	if (ret < 0) {
 		mlog_errno(ret);
 		goto leave;
@@ -3727,6 +3727,7 @@ leave:
 	if (meta_ac)
 		ocfs2_free_alloc_context(meta_ac);
 
+	ocfs2_put_extent_tree(&et);
 	return ret;
 }
 
@@ -4331,9 +4332,11 @@ static int ocfs2_rm_xattr_cluster(struct inode *inode,
 	handle_t *handle;
 	struct ocfs2_xattr_block *xb =
 			(struct ocfs2_xattr_block *)root_bh->b_data;
-	struct ocfs2_extent_list *root_el = &xb->xb_attrs.xb_root.xt_list;
 	struct ocfs2_alloc_context *meta_ac = NULL;
 	struct ocfs2_cached_dealloc_ctxt dealloc;
+	struct ocfs2_extent_tree et;
+
+	ocfs2_get_xattr_tree_extent_tree(&et, inode, root_bh);
 
 	ocfs2_init_dealloc_ctxt(&dealloc);
 
@@ -4342,10 +4345,9 @@ static int ocfs2_rm_xattr_cluster(struct inode *inode,
 
 	ocfs2_remove_xattr_clusters_from_cache(inode, blkno, len);
 
-	ret = ocfs2_lock_allocators(inode, root_bh, root_el,
-				    0, 1, NULL, &meta_ac,
-				    OCFS2_XATTR_TREE_EXTENT, NULL);
+	ret = ocfs2_lock_allocators(inode, &et, 0, 1, NULL, &meta_ac);
 	if (ret) {
+		ocfs2_put_extent_tree(&et);
 		mlog_errno(ret);
 		return ret;
 	}
@@ -4374,8 +4376,8 @@ static int ocfs2_rm_xattr_cluster(struct inode *inode,
 		goto out_commit;
 	}
 
-	ret = ocfs2_remove_extent(inode, root_bh, cpos, len, handle, meta_ac,
-				  &dealloc, OCFS2_XATTR_TREE_EXTENT, NULL);
+	ret = ocfs2_remove_extent(inode, &et, cpos, len, handle, meta_ac,
+				  &dealloc);
 	if (ret) {
 		mlog_errno(ret);
 		goto out_commit;
@@ -4405,6 +4407,7 @@ out:
 
 	ocfs2_run_deallocs(osb, &dealloc);
 
+	ocfs2_put_extent_tree(&et);
 	return ret;
 }