Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 7704 insertions, 0 deletions

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
new file mode 100644
index 0000000000..aef58f1395
--- /dev/null
+++ b/fs/ocfs2/alloc.c
@@ -0,0 +1,7704 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * alloc.c
+ *
+ * Extent allocs and frees
+ *
+ * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
+ */
+
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/highmem.h>
+#include <linux/swap.h>
+#include <linux/quotaops.h>
+#include <linux/blkdev.h>
+#include <linux/sched/signal.h>
+
+#include <cluster/masklog.h>
+
+#include "ocfs2.h"
+
+#include "alloc.h"
+#include "aops.h"
+#include "blockcheck.h"
+#include "dlmglue.h"
+#include "extent_map.h"
+#include "inode.h"
+#include "journal.h"
+#include "localalloc.h"
+#include "suballoc.h"
+#include "sysfile.h"
+#include "file.h"
+#include "super.h"
+#include "uptodate.h"
+#include "xattr.h"
+#include "refcounttree.h"
+#include "ocfs2_trace.h"
+
+#include "buffer_head_io.h"
+
+enum ocfs2_contig_type {
+	CONTIG_NONE = 0,
+	CONTIG_LEFT,
+	CONTIG_RIGHT,
+	CONTIG_LEFTRIGHT,
+};
+
+static enum ocfs2_contig_type
+	ocfs2_extent_rec_contig(struct super_block *sb,
+				struct ocfs2_extent_rec *ext,
+				struct ocfs2_extent_rec *insert_rec);
+/*
+ * Operations for a specific extent tree type.
+ *
+ * To implement an on-disk btree (extent tree) type in ocfs2, add
+ * an ocfs2_extent_tree_operations structure and the matching
+ * ocfs2_init_<thingy>_extent_tree() function.  That's pretty much it
+ * for the allocation portion of the extent tree.
+ */
+struct ocfs2_extent_tree_operations {
+	/*
+	 * last_eb_blk is the block number of the right most leaf extent
+	 * block.  Most on-disk structures containing an extent tree store
+	 * this value for fast access.  The ->eo_set_last_eb_blk() and
+	 * ->eo_get_last_eb_blk() operations access this value.  They are
+	 *  both required.
+	 */
+	void (*eo_set_last_eb_blk)(struct ocfs2_extent_tree *et,
+				   u64 blkno);
+	u64 (*eo_get_last_eb_blk)(struct ocfs2_extent_tree *et);
+
+	/*
+	 * The on-disk structure usually keeps track of how many total
+	 * clusters are stored in this extent tree.  This function updates
+	 * that value.  new_clusters is the delta, and must be
+	 * added to the total.  Required.
+	 */
+	void (*eo_update_clusters)(struct ocfs2_extent_tree *et,
+				   u32 new_clusters);
+
+	/*
+	 * If this extent tree is supported by an extent map, insert
+	 * a record into the map.
+	 */
+	void (*eo_extent_map_insert)(struct ocfs2_extent_tree *et,
+				     struct ocfs2_extent_rec *rec);
+
+	/*
+	 * If this extent tree is supported by an extent map, truncate the
+	 * map to clusters,
+	 */
+	void (*eo_extent_map_truncate)(struct ocfs2_extent_tree *et,
+				       u32 clusters);
+
+	/*
+	 * If ->eo_insert_check() exists, it is called before rec is
+	 * inserted into the extent tree.  It is optional.
+	 */
+	int (*eo_insert_check)(struct ocfs2_extent_tree *et,
+			       struct ocfs2_extent_rec *rec);
+	int (*eo_sanity_check)(struct ocfs2_extent_tree *et);
+
+	/*
+	 * --------------------------------------------------------------
+	 * The remaining are internal to ocfs2_extent_tree and don't have
+	 * accessor functions
+	 */
+
+	/*
+	 * ->eo_fill_root_el() takes et->et_object and sets et->et_root_el.
+	 * It is required.
+	 */
+	void (*eo_fill_root_el)(struct ocfs2_extent_tree *et);
+
+	/*
+	 * ->eo_fill_max_leaf_clusters sets et->et_max_leaf_clusters if
+	 * it exists.  If it does not, et->et_max_leaf_clusters is set
+	 * to 0 (unlimited).  Optional.
+	 */
+	void (*eo_fill_max_leaf_clusters)(struct ocfs2_extent_tree *et);
+
+	/*
+	 * ->eo_extent_contig test whether the 2 ocfs2_extent_rec
+	 * are contiguous or not. Optional. Don't need to set it if use
+	 * ocfs2_extent_rec as the tree leaf.
+	 */
+	enum ocfs2_contig_type
+		(*eo_extent_contig)(struct ocfs2_extent_tree *et,
+				    struct ocfs2_extent_rec *ext,
+				    struct ocfs2_extent_rec *insert_rec);
+};
+
+
+/*
+ * 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 ocfs2_extent_tree *et,
+					 u32 clusters);
+static void ocfs2_dinode_extent_map_insert(struct ocfs2_extent_tree *et,
+					   struct ocfs2_extent_rec *rec);
+static void ocfs2_dinode_extent_map_truncate(struct ocfs2_extent_tree *et,
+					     u32 clusters);
+static int ocfs2_dinode_insert_check(struct ocfs2_extent_tree *et,
+				     struct ocfs2_extent_rec *rec);
+static int ocfs2_dinode_sanity_check(struct ocfs2_extent_tree *et);
+static void ocfs2_dinode_fill_root_el(struct ocfs2_extent_tree *et);
+
+static int ocfs2_reuse_blk_from_dealloc(handle_t *handle,
+					struct ocfs2_extent_tree *et,
+					struct buffer_head **new_eb_bh,
+					int blk_wanted, int *blk_given);
+static int ocfs2_is_dealloc_empty(struct ocfs2_extent_tree *et);
+
+static const 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_extent_map_insert	= ocfs2_dinode_extent_map_insert,
+	.eo_extent_map_truncate	= ocfs2_dinode_extent_map_truncate,
+	.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_ops != &ocfs2_dinode_et_ops);
+	di->i_last_eb_blk = cpu_to_le64(blkno);
+}
+
+static u64 ocfs2_dinode_get_last_eb_blk(struct ocfs2_extent_tree *et)
+{
+	struct ocfs2_dinode *di = et->et_object;
+
+	BUG_ON(et->et_ops != &ocfs2_dinode_et_ops);
+	return le64_to_cpu(di->i_last_eb_blk);
+}
+
+static void ocfs2_dinode_update_clusters(struct ocfs2_extent_tree *et,
+					 u32 clusters)
+{
+	struct ocfs2_inode_info *oi = cache_info_to_inode(et->et_ci);
+	struct ocfs2_dinode *di = et->et_object;
+
+	le32_add_cpu(&di->i_clusters, clusters);
+	spin_lock(&oi->ip_lock);
+	oi->ip_clusters = le32_to_cpu(di->i_clusters);
+	spin_unlock(&oi->ip_lock);
+}
+
+static void ocfs2_dinode_extent_map_insert(struct ocfs2_extent_tree *et,
+					   struct ocfs2_extent_rec *rec)
+{
+	struct inode *inode = &cache_info_to_inode(et->et_ci)->vfs_inode;
+
+	ocfs2_extent_map_insert_rec(inode, rec);
+}
+
+static void ocfs2_dinode_extent_map_truncate(struct ocfs2_extent_tree *et,
+					     u32 clusters)
+{
+	struct inode *inode = &cache_info_to_inode(et->et_ci)->vfs_inode;
+
+	ocfs2_extent_map_trunc(inode, clusters);
+}
+
+static int ocfs2_dinode_insert_check(struct ocfs2_extent_tree *et,
+				     struct ocfs2_extent_rec *rec)
+{
+	struct ocfs2_inode_info *oi = cache_info_to_inode(et->et_ci);
+	struct ocfs2_super *osb = OCFS2_SB(oi->vfs_inode.i_sb);
+
+	BUG_ON(oi->ip_dyn_features & OCFS2_INLINE_DATA_FL);
+	mlog_bug_on_msg(!ocfs2_sparse_alloc(osb) &&
+			(oi->ip_clusters != le32_to_cpu(rec->e_cpos)),
+			"Device %s, asking for sparse allocation: inode %llu, "
+			"cpos %u, clusters %u\n",
+			osb->dev_str,
+			(unsigned long long)oi->ip_blkno,
+			rec->e_cpos, oi->ip_clusters);
+
+	return 0;
+}
+
+static int ocfs2_dinode_sanity_check(struct ocfs2_extent_tree *et)
+{
+	struct ocfs2_dinode *di = et->et_object;
+
+	BUG_ON(et->et_ops != &ocfs2_dinode_et_ops);
+	BUG_ON(!OCFS2_IS_VALID_DINODE(di));
+
+	return 0;
+}
+
+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)
+{
+	struct ocfs2_xattr_value_buf *vb = et->et_object;
+
+	et->et_root_el = &vb->vb_xv->xr_list;
+}
+
+static void ocfs2_xattr_value_set_last_eb_blk(struct ocfs2_extent_tree *et,
+					      u64 blkno)
+{
+	struct ocfs2_xattr_value_buf *vb = et->et_object;
+
+	vb->vb_xv->xr_last_eb_blk = cpu_to_le64(blkno);
+}
+
+static u64 ocfs2_xattr_value_get_last_eb_blk(struct ocfs2_extent_tree *et)
+{
+	struct ocfs2_xattr_value_buf *vb = et->et_object;
+
+	return le64_to_cpu(vb->vb_xv->xr_last_eb_blk);
+}
+
+static void ocfs2_xattr_value_update_clusters(struct ocfs2_extent_tree *et,
+					      u32 clusters)
+{
+	struct ocfs2_xattr_value_buf *vb = et->et_object;
+
+	le32_add_cpu(&vb->vb_xv->xr_clusters, clusters);
+}
+
+static const struct ocfs2_extent_tree_operations ocfs2_xattr_value_et_ops = {
+	.eo_set_last_eb_blk	= ocfs2_xattr_value_set_last_eb_blk,
+	.eo_get_last_eb_blk	= ocfs2_xattr_value_get_last_eb_blk,
+	.eo_update_clusters	= ocfs2_xattr_value_update_clusters,
+	.eo_fill_root_el	= ocfs2_xattr_value_fill_root_el,
+};
+
+static void ocfs2_xattr_tree_fill_root_el(struct ocfs2_extent_tree *et)
+{
+	struct ocfs2_xattr_block *xb = et->et_object;
+
+	et->et_root_el = &xb->xb_attrs.xb_root.xt_list;
+}
+
+static void ocfs2_xattr_tree_fill_max_leaf_clusters(struct ocfs2_extent_tree *et)
+{
+	struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
+	et->et_max_leaf_clusters =
+		ocfs2_clusters_for_bytes(sb, OCFS2_MAX_XATTR_TREE_LEAF_SIZE);
+}
+
+static void ocfs2_xattr_tree_set_last_eb_blk(struct ocfs2_extent_tree *et,
+					     u64 blkno)
+{
+	struct ocfs2_xattr_block *xb = et->et_object;
+	struct ocfs2_xattr_tree_root *xt = &xb->xb_attrs.xb_root;
+
+	xt->xt_last_eb_blk = cpu_to_le64(blkno);
+}
+
+static u64 ocfs2_xattr_tree_get_last_eb_blk(struct ocfs2_extent_tree *et)
+{
+	struct ocfs2_xattr_block *xb = et->et_object;
+	struct ocfs2_xattr_tree_root *xt = &xb->xb_attrs.xb_root;
+
+	return le64_to_cpu(xt->xt_last_eb_blk);
+}
+
+static void ocfs2_xattr_tree_update_clusters(struct ocfs2_extent_tree *et,
+					     u32 clusters)
+{
+	struct ocfs2_xattr_block *xb = et->et_object;
+
+	le32_add_cpu(&xb->xb_attrs.xb_root.xt_clusters, clusters);
+}
+
+static const struct ocfs2_extent_tree_operations ocfs2_xattr_tree_et_ops = {
+	.eo_set_last_eb_blk	= ocfs2_xattr_tree_set_last_eb_blk,
+	.eo_get_last_eb_blk	= ocfs2_xattr_tree_get_last_eb_blk,
+	.eo_update_clusters	= ocfs2_xattr_tree_update_clusters,
+	.eo_fill_root_el	= ocfs2_xattr_tree_fill_root_el,
+	.eo_fill_max_leaf_clusters = ocfs2_xattr_tree_fill_max_leaf_clusters,
+};
+
+static void ocfs2_dx_root_set_last_eb_blk(struct ocfs2_extent_tree *et,
+					  u64 blkno)
+{
+	struct ocfs2_dx_root_block *dx_root = et->et_object;
+
+	dx_root->dr_last_eb_blk = cpu_to_le64(blkno);
+}
+
+static u64 ocfs2_dx_root_get_last_eb_blk(struct ocfs2_extent_tree *et)
+{
+	struct ocfs2_dx_root_block *dx_root = et->et_object;
+
+	return le64_to_cpu(dx_root->dr_last_eb_blk);
+}
+
+static void ocfs2_dx_root_update_clusters(struct ocfs2_extent_tree *et,
+					  u32 clusters)
+{
+	struct ocfs2_dx_root_block *dx_root = et->et_object;
+
+	le32_add_cpu(&dx_root->dr_clusters, clusters);
+}
+
+static int ocfs2_dx_root_sanity_check(struct ocfs2_extent_tree *et)
+{
+	struct ocfs2_dx_root_block *dx_root = et->et_object;
+
+	BUG_ON(!OCFS2_IS_VALID_DX_ROOT(dx_root));
+
+	return 0;
+}
+
+static void ocfs2_dx_root_fill_root_el(struct ocfs2_extent_tree *et)
+{
+	struct ocfs2_dx_root_block *dx_root = et->et_object;
+
+	et->et_root_el = &dx_root->dr_list;
+}
+
+static const struct ocfs2_extent_tree_operations ocfs2_dx_root_et_ops = {
+	.eo_set_last_eb_blk	= ocfs2_dx_root_set_last_eb_blk,
+	.eo_get_last_eb_blk	= ocfs2_dx_root_get_last_eb_blk,
+	.eo_update_clusters	= ocfs2_dx_root_update_clusters,
+	.eo_sanity_check	= ocfs2_dx_root_sanity_check,
+	.eo_fill_root_el	= ocfs2_dx_root_fill_root_el,
+};
+
+static void ocfs2_refcount_tree_fill_root_el(struct ocfs2_extent_tree *et)
+{
+	struct ocfs2_refcount_block *rb = et->et_object;
+
+	et->et_root_el = &rb->rf_list;
+}
+
+static void ocfs2_refcount_tree_set_last_eb_blk(struct ocfs2_extent_tree *et,
+						u64 blkno)
+{
+	struct ocfs2_refcount_block *rb = et->et_object;
+
+	rb->rf_last_eb_blk = cpu_to_le64(blkno);
+}
+
+static u64 ocfs2_refcount_tree_get_last_eb_blk(struct ocfs2_extent_tree *et)
+{
+	struct ocfs2_refcount_block *rb = et->et_object;
+
+	return le64_to_cpu(rb->rf_last_eb_blk);
+}
+
+static void ocfs2_refcount_tree_update_clusters(struct ocfs2_extent_tree *et,
+						u32 clusters)
+{
+	struct ocfs2_refcount_block *rb = et->et_object;
+
+	le32_add_cpu(&rb->rf_clusters, clusters);
+}
+
+static enum ocfs2_contig_type
+ocfs2_refcount_tree_extent_contig(struct ocfs2_extent_tree *et,
+				  struct ocfs2_extent_rec *ext,
+				  struct ocfs2_extent_rec *insert_rec)
+{
+	return CONTIG_NONE;
+}
+
+static const struct ocfs2_extent_tree_operations ocfs2_refcount_tree_et_ops = {
+	.eo_set_last_eb_blk	= ocfs2_refcount_tree_set_last_eb_blk,
+	.eo_get_last_eb_blk	= ocfs2_refcount_tree_get_last_eb_blk,
+	.eo_update_clusters	= ocfs2_refcount_tree_update_clusters,
+	.eo_fill_root_el	= ocfs2_refcount_tree_fill_root_el,
+	.eo_extent_contig	= ocfs2_refcount_tree_extent_contig,
+};
+
+static void __ocfs2_init_extent_tree(struct ocfs2_extent_tree *et,
+				     struct ocfs2_caching_info *ci,
+				     struct buffer_head *bh,
+				     ocfs2_journal_access_func access,
+				     void *obj,
+				     const struct ocfs2_extent_tree_operations *ops)
+{
+	et->et_ops = ops;
+	et->et_root_bh = bh;
+	et->et_ci = ci;
+	et->et_root_journal_access = access;
+	if (!obj)
+		obj = (void *)bh->b_data;
+	et->et_object = obj;
+	et->et_dealloc = NULL;
+
+	et->et_ops->eo_fill_root_el(et);
+	if (!et->et_ops->eo_fill_max_leaf_clusters)
+		et->et_max_leaf_clusters = 0;
+	else
+		et->et_ops->eo_fill_max_leaf_clusters(et);
+}
+
+void ocfs2_init_dinode_extent_tree(struct ocfs2_extent_tree *et,
+				   struct ocfs2_caching_info *ci,
+				   struct buffer_head *bh)
+{
+	__ocfs2_init_extent_tree(et, ci, bh, ocfs2_journal_access_di,
+				 NULL, &ocfs2_dinode_et_ops);
+}
+
+void ocfs2_init_xattr_tree_extent_tree(struct ocfs2_extent_tree *et,
+				       struct ocfs2_caching_info *ci,
+				       struct buffer_head *bh)
+{
+	__ocfs2_init_extent_tree(et, ci, bh, ocfs2_journal_access_xb,
+				 NULL, &ocfs2_xattr_tree_et_ops);
+}
+
+void ocfs2_init_xattr_value_extent_tree(struct ocfs2_extent_tree *et,
+					struct ocfs2_caching_info *ci,
+					struct ocfs2_xattr_value_buf *vb)
+{
+	__ocfs2_init_extent_tree(et, ci, vb->vb_bh, vb->vb_access, vb,
+				 &ocfs2_xattr_value_et_ops);
+}
+
+void ocfs2_init_dx_root_extent_tree(struct ocfs2_extent_tree *et,
+				    struct ocfs2_caching_info *ci,
+				    struct buffer_head *bh)
+{
+	__ocfs2_init_extent_tree(et, ci, bh, ocfs2_journal_access_dr,
+				 NULL, &ocfs2_dx_root_et_ops);
+}
+
+void ocfs2_init_refcount_extent_tree(struct ocfs2_extent_tree *et,
+				     struct ocfs2_caching_info *ci,
+				     struct buffer_head *bh)
+{
+	__ocfs2_init_extent_tree(et, ci, bh, ocfs2_journal_access_rb,
+				 NULL, &ocfs2_refcount_tree_et_ops);
+}
+
+static inline void ocfs2_et_set_last_eb_blk(struct ocfs2_extent_tree *et,
+					    u64 new_last_eb_blk)
+{
+	et->et_ops->eo_set_last_eb_blk(et, new_last_eb_blk);
+}
+
+static inline u64 ocfs2_et_get_last_eb_blk(struct ocfs2_extent_tree *et)
+{
+	return et->et_ops->eo_get_last_eb_blk(et);
+}
+
+static inline void ocfs2_et_update_clusters(struct ocfs2_extent_tree *et,
+					    u32 clusters)
+{
+	et->et_ops->eo_update_clusters(et, clusters);
+}
+
+static inline void ocfs2_et_extent_map_insert(struct ocfs2_extent_tree *et,
+					      struct ocfs2_extent_rec *rec)
+{
+	if (et->et_ops->eo_extent_map_insert)
+		et->et_ops->eo_extent_map_insert(et, rec);
+}
+
+static inline void ocfs2_et_extent_map_truncate(struct ocfs2_extent_tree *et,
+						u32 clusters)
+{
+	if (et->et_ops->eo_extent_map_truncate)
+		et->et_ops->eo_extent_map_truncate(et, clusters);
+}
+
+static inline int ocfs2_et_root_journal_access(handle_t *handle,
+					       struct ocfs2_extent_tree *et,
+					       int type)
+{
+	return et->et_root_journal_access(handle, et->et_ci, et->et_root_bh,
+					  type);
+}
+
+static inline enum ocfs2_contig_type
+	ocfs2_et_extent_contig(struct ocfs2_extent_tree *et,
+			       struct ocfs2_extent_rec *rec,
+			       struct ocfs2_extent_rec *insert_rec)
+{
+	if (et->et_ops->eo_extent_contig)
+		return et->et_ops->eo_extent_contig(et, rec, insert_rec);
+
+	return ocfs2_extent_rec_contig(
+				ocfs2_metadata_cache_get_super(et->et_ci),
+				rec, insert_rec);
+}
+
+static inline int ocfs2_et_insert_check(struct ocfs2_extent_tree *et,
+					struct ocfs2_extent_rec *rec)
+{
+	int ret = 0;
+
+	if (et->et_ops->eo_insert_check)
+		ret = et->et_ops->eo_insert_check(et, rec);
+	return ret;
+}
+
+static inline int ocfs2_et_sanity_check(struct ocfs2_extent_tree *et)
+{
+	int ret = 0;
+
+	if (et->et_ops->eo_sanity_check)
+		ret = et->et_ops->eo_sanity_check(et);
+	return ret;
+}
+
+static int ocfs2_cache_extent_block_free(struct ocfs2_cached_dealloc_ctxt *ctxt,
+					 struct ocfs2_extent_block *eb);
+static void ocfs2_adjust_rightmost_records(handle_t *handle,
+					   struct ocfs2_extent_tree *et,
+					   struct ocfs2_path *path,
+					   struct ocfs2_extent_rec *insert_rec);
+/*
+ * Reset the actual path elements so that we can re-use the structure
+ * to build another path. Generally, this involves freeing the buffer
+ * heads.
+ */
+void ocfs2_reinit_path(struct ocfs2_path *path, int keep_root)
+{
+	int i, start = 0, depth = 0;
+	struct ocfs2_path_item *node;
+
+	if (keep_root)
+		start = 1;
+
+	for(i = start; i < path_num_items(path); i++) {
+		node = &path->p_node[i];
+
+		brelse(node->bh);
+		node->bh = NULL;
+		node->el = NULL;
+	}
+
+	/*
+	 * Tree depth may change during truncate, or insert. If we're
+	 * keeping the root extent list, then make sure that our path
+	 * structure reflects the proper depth.
+	 */
+	if (keep_root)
+		depth = le16_to_cpu(path_root_el(path)->l_tree_depth);
+	else
+		path_root_access(path) = NULL;
+
+	path->p_tree_depth = depth;
+}
+
+void ocfs2_free_path(struct ocfs2_path *path)
+{
+	if (path) {
+		ocfs2_reinit_path(path, 0);
+		kfree(path);
+	}
+}
+
+/*
+ * All the elements of src into dest. After this call, src could be freed
+ * without affecting dest.
+ *
+ * Both paths should have the same root. Any non-root elements of dest
+ * will be freed.
+ */
+static void ocfs2_cp_path(struct ocfs2_path *dest, struct ocfs2_path *src)
+{
+	int i;
+
+	BUG_ON(path_root_bh(dest) != path_root_bh(src));
+	BUG_ON(path_root_el(dest) != path_root_el(src));
+	BUG_ON(path_root_access(dest) != path_root_access(src));
+
+	ocfs2_reinit_path(dest, 1);
+
+	for(i = 1; i < OCFS2_MAX_PATH_DEPTH; i++) {
+		dest->p_node[i].bh = src->p_node[i].bh;
+		dest->p_node[i].el = src->p_node[i].el;
+
+		if (dest->p_node[i].bh)
+			get_bh(dest->p_node[i].bh);
+	}
+}
+
+/*
+ * Make the *dest path the same as src and re-initialize src path to
+ * have a root only.
+ */
+static void ocfs2_mv_path(struct ocfs2_path *dest, struct ocfs2_path *src)
+{
+	int i;
+
+	BUG_ON(path_root_bh(dest) != path_root_bh(src));
+	BUG_ON(path_root_access(dest) != path_root_access(src));
+
+	for(i = 1; i < OCFS2_MAX_PATH_DEPTH; i++) {
+		brelse(dest->p_node[i].bh);
+
+		dest->p_node[i].bh = src->p_node[i].bh;
+		dest->p_node[i].el = src->p_node[i].el;
+
+		src->p_node[i].bh = NULL;
+		src->p_node[i].el = NULL;
+	}
+}
+
+/*
+ * Insert an extent block at given index.
+ *
+ * This will not take an additional reference on eb_bh.
+ */
+static inline void ocfs2_path_insert_eb(struct ocfs2_path *path, int index,
+					struct buffer_head *eb_bh)
+{
+	struct ocfs2_extent_block *eb = (struct ocfs2_extent_block *)eb_bh->b_data;
+
+	/*
+	 * Right now, no root bh is an extent block, so this helps
+	 * catch code errors with dinode trees. The assertion can be
+	 * safely removed if we ever need to insert extent block
+	 * structures at the root.
+	 */
+	BUG_ON(index == 0);
+
+	path->p_node[index].bh = eb_bh;
+	path->p_node[index].el = &eb->h_list;
+}
+
+static struct ocfs2_path *ocfs2_new_path(struct buffer_head *root_bh,
+					 struct ocfs2_extent_list *root_el,
+					 ocfs2_journal_access_func access)
+{
+	struct ocfs2_path *path;
+
+	BUG_ON(le16_to_cpu(root_el->l_tree_depth) >= OCFS2_MAX_PATH_DEPTH);
+
+	path = kzalloc(sizeof(*path), GFP_NOFS);
+	if (path) {
+		path->p_tree_depth = le16_to_cpu(root_el->l_tree_depth);
+		get_bh(root_bh);
+		path_root_bh(path) = root_bh;
+		path_root_el(path) = root_el;
+		path_root_access(path) = access;
+	}
+
+	return path;
+}
+
+struct ocfs2_path *ocfs2_new_path_from_path(struct ocfs2_path *path)
+{
+	return ocfs2_new_path(path_root_bh(path), path_root_el(path),
+			      path_root_access(path));
+}
+
+struct ocfs2_path *ocfs2_new_path_from_et(struct ocfs2_extent_tree *et)
+{
+	return ocfs2_new_path(et->et_root_bh, et->et_root_el,
+			      et->et_root_journal_access);
+}
+
+/*
+ * Journal the buffer at depth idx.  All idx>0 are extent_blocks,
+ * otherwise it's the root_access function.
+ *
+ * I don't like the way this function's name looks next to
+ * ocfs2_journal_access_path(), but I don't have a better one.
+ */
+int ocfs2_path_bh_journal_access(handle_t *handle,
+				 struct ocfs2_caching_info *ci,
+				 struct ocfs2_path *path,
+				 int idx)
+{
+	ocfs2_journal_access_func access = path_root_access(path);
+
+	if (!access)
+		access = ocfs2_journal_access;
+
+	if (idx)
+		access = ocfs2_journal_access_eb;
+
+	return access(handle, ci, path->p_node[idx].bh,
+		      OCFS2_JOURNAL_ACCESS_WRITE);
+}
+
+/*
+ * Convenience function to journal all components in a path.
+ */
+int ocfs2_journal_access_path(struct ocfs2_caching_info *ci,
+			      handle_t *handle,
+			      struct ocfs2_path *path)
+{
+	int i, ret = 0;
+
+	if (!path)
+		goto out;
+
+	for(i = 0; i < path_num_items(path); i++) {
+		ret = ocfs2_path_bh_journal_access(handle, ci, path, i);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+out:
+	return ret;
+}
+
+/*
+ * Return the index of the extent record which contains cluster #v_cluster.
+ * -1 is returned if it was not found.
+ *
+ * Should work fine on interior and exterior nodes.
+ */
+int ocfs2_search_extent_list(struct ocfs2_extent_list *el, u32 v_cluster)
+{
+	int ret = -1;
+	int i;
+	struct ocfs2_extent_rec *rec;
+	u32 rec_end, rec_start, clusters;
+
+	for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
+		rec = &el->l_recs[i];
+
+		rec_start = le32_to_cpu(rec->e_cpos);
+		clusters = ocfs2_rec_clusters(el, rec);
+
+		rec_end = rec_start + clusters;
+
+		if (v_cluster >= rec_start && v_cluster < rec_end) {
+			ret = i;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+/*
+ * NOTE: ocfs2_block_extent_contig(), ocfs2_extents_adjacent() and
+ * ocfs2_extent_rec_contig only work properly against leaf nodes!
+ */
+static int ocfs2_block_extent_contig(struct super_block *sb,
+				     struct ocfs2_extent_rec *ext,
+				     u64 blkno)
+{
+	u64 blk_end = le64_to_cpu(ext->e_blkno);
+
+	blk_end += ocfs2_clusters_to_blocks(sb,
+				    le16_to_cpu(ext->e_leaf_clusters));
+
+	return blkno == blk_end;
+}
+
+static int ocfs2_extents_adjacent(struct ocfs2_extent_rec *left,
+				  struct ocfs2_extent_rec *right)
+{
+	u32 left_range;
+
+	left_range = le32_to_cpu(left->e_cpos) +
+		le16_to_cpu(left->e_leaf_clusters);
+
+	return (left_range == le32_to_cpu(right->e_cpos));
+}
+
+static enum ocfs2_contig_type
+	ocfs2_extent_rec_contig(struct super_block *sb,
+				struct ocfs2_extent_rec *ext,
+				struct ocfs2_extent_rec *insert_rec)
+{
+	u64 blkno = le64_to_cpu(insert_rec->e_blkno);
+
+	/*
+	 * Refuse to coalesce extent records with different flag
+	 * fields - we don't want to mix unwritten extents with user
+	 * data.
+	 */
+	if (ext->e_flags != insert_rec->e_flags)
+		return CONTIG_NONE;
+
+	if (ocfs2_extents_adjacent(ext, insert_rec) &&
+	    ocfs2_block_extent_contig(sb, ext, blkno))
+			return CONTIG_RIGHT;
+
+	blkno = le64_to_cpu(ext->e_blkno);
+	if (ocfs2_extents_adjacent(insert_rec, ext) &&
+	    ocfs2_block_extent_contig(sb, insert_rec, blkno))
+		return CONTIG_LEFT;
+
+	return CONTIG_NONE;
+}
+
+/*
+ * NOTE: We can have pretty much any combination of contiguousness and
+ * appending.
+ *
+ * The usefulness of APPEND_TAIL is more in that it lets us know that
+ * we'll have to update the path to that leaf.
+ */
+enum ocfs2_append_type {
+	APPEND_NONE = 0,
+	APPEND_TAIL,
+};
+
+enum ocfs2_split_type {
+	SPLIT_NONE = 0,
+	SPLIT_LEFT,
+	SPLIT_RIGHT,
+};
+
+struct ocfs2_insert_type {
+	enum ocfs2_split_type	ins_split;
+	enum ocfs2_append_type	ins_appending;
+	enum ocfs2_contig_type	ins_contig;
+	int			ins_contig_index;
+	int			ins_tree_depth;
+};
+
+struct ocfs2_merge_ctxt {
+	enum ocfs2_contig_type	c_contig_type;
+	int			c_has_empty_extent;
+	int			c_split_covers_rec;
+};
+
+static int ocfs2_validate_extent_block(struct super_block *sb,
+				       struct buffer_head *bh)
+{
+	int rc;
+	struct ocfs2_extent_block *eb =
+		(struct ocfs2_extent_block *)bh->b_data;
+
+	trace_ocfs2_validate_extent_block((unsigned long long)bh->b_blocknr);
+
+	BUG_ON(!buffer_uptodate(bh));
+
+	/*
+	 * If the ecc fails, we return the error but otherwise
+	 * leave the filesystem running.  We know any error is
+	 * local to this block.
+	 */
+	rc = ocfs2_validate_meta_ecc(sb, bh->b_data, &eb->h_check);
+	if (rc) {
+		mlog(ML_ERROR, "Checksum failed for extent block %llu\n",
+		     (unsigned long long)bh->b_blocknr);
+		return rc;
+	}
+
+	/*
+	 * Errors after here are fatal.
+	 */
+
+	if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
+		rc = ocfs2_error(sb,
+				 "Extent block #%llu has bad signature %.*s\n",
+				 (unsigned long long)bh->b_blocknr, 7,
+				 eb->h_signature);
+		goto bail;
+	}
+
+	if (le64_to_cpu(eb->h_blkno) != bh->b_blocknr) {
+		rc = ocfs2_error(sb,
+				 "Extent block #%llu has an invalid h_blkno of %llu\n",
+				 (unsigned long long)bh->b_blocknr,
+				 (unsigned long long)le64_to_cpu(eb->h_blkno));
+		goto bail;
+	}
+
+	if (le32_to_cpu(eb->h_fs_generation) != OCFS2_SB(sb)->fs_generation)
+		rc = ocfs2_error(sb,
+				 "Extent block #%llu has an invalid h_fs_generation of #%u\n",
+				 (unsigned long long)bh->b_blocknr,
+				 le32_to_cpu(eb->h_fs_generation));
+bail:
+	return rc;
+}
+
+int ocfs2_read_extent_block(struct ocfs2_caching_info *ci, u64 eb_blkno,
+			    struct buffer_head **bh)
+{
+	int rc;
+	struct buffer_head *tmp = *bh;
+
+	rc = ocfs2_read_block(ci, eb_blkno, &tmp,
+			      ocfs2_validate_extent_block);
+
+	/* If ocfs2_read_block() got us a new bh, pass it up. */
+	if (!rc && !*bh)
+		*bh = tmp;
+
+	return rc;
+}
+
+
+/*
+ * How many free extents have we got before we need more meta data?
+ */
+int ocfs2_num_free_extents(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;
+
+	el = et->et_root_el;
+	last_eb_blk = ocfs2_et_get_last_eb_blk(et);
+
+	if (last_eb_blk) {
+		retval = ocfs2_read_extent_block(et->et_ci, last_eb_blk,
+						 &eb_bh);
+		if (retval < 0) {
+			mlog_errno(retval);
+			goto bail;
+		}
+		eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+		el = &eb->h_list;
+	}
+
+	BUG_ON(el->l_tree_depth != 0);
+
+	retval = le16_to_cpu(el->l_count) - le16_to_cpu(el->l_next_free_rec);
+bail:
+	brelse(eb_bh);
+
+	trace_ocfs2_num_free_extents(retval);
+	return retval;
+}
+
+/* expects array to already be allocated
+ *
+ * sets h_signature, h_blkno, h_suballoc_bit, h_suballoc_slot, and
+ * l_count for you
+ */
+static int ocfs2_create_new_meta_bhs(handle_t *handle,
+				     struct ocfs2_extent_tree *et,
+				     int wanted,
+				     struct ocfs2_alloc_context *meta_ac,
+				     struct buffer_head *bhs[])
+{
+	int count, status, i;
+	u16 suballoc_bit_start;
+	u32 num_got;
+	u64 suballoc_loc, first_blkno;
+	struct ocfs2_super *osb =
+		OCFS2_SB(ocfs2_metadata_cache_get_super(et->et_ci));
+	struct ocfs2_extent_block *eb;
+
+	count = 0;
+	while (count < wanted) {
+		status = ocfs2_claim_metadata(handle,
+					      meta_ac,
+					      wanted - count,
+					      &suballoc_loc,
+					      &suballoc_bit_start,
+					      &num_got,
+					      &first_blkno);
+		if (status < 0) {
+			mlog_errno(status);
+			goto bail;
+		}
+
+		for(i = count;  i < (num_got + count); i++) {
+			bhs[i] = sb_getblk(osb->sb, first_blkno);
+			if (bhs[i] == NULL) {
+				status = -ENOMEM;
+				mlog_errno(status);
+				goto bail;
+			}
+			ocfs2_set_new_buffer_uptodate(et->et_ci, bhs[i]);
+
+			status = ocfs2_journal_access_eb(handle, et->et_ci,
+							 bhs[i],
+							 OCFS2_JOURNAL_ACCESS_CREATE);
+			if (status < 0) {
+				mlog_errno(status);
+				goto bail;
+			}
+
+			memset(bhs[i]->b_data, 0, osb->sb->s_blocksize);
+			eb = (struct ocfs2_extent_block *) bhs[i]->b_data;
+			/* Ok, setup the minimal stuff here. */
+			strcpy(eb->h_signature, OCFS2_EXTENT_BLOCK_SIGNATURE);
+			eb->h_blkno = cpu_to_le64(first_blkno);
+			eb->h_fs_generation = cpu_to_le32(osb->fs_generation);
+			eb->h_suballoc_slot =
+				cpu_to_le16(meta_ac->ac_alloc_slot);
+			eb->h_suballoc_loc = cpu_to_le64(suballoc_loc);
+			eb->h_suballoc_bit = cpu_to_le16(suballoc_bit_start);
+			eb->h_list.l_count =
+				cpu_to_le16(ocfs2_extent_recs_per_eb(osb->sb));
+
+			suballoc_bit_start++;
+			first_blkno++;
+
+			/* We'll also be dirtied by the caller, so
+			 * this isn't absolutely necessary. */
+			ocfs2_journal_dirty(handle, bhs[i]);
+		}
+
+		count += num_got;
+	}
+
+	status = 0;
+bail:
+	if (status < 0) {
+		for(i = 0; i < wanted; i++) {
+			brelse(bhs[i]);
+			bhs[i] = NULL;
+		}
+	}
+	return status;
+}
+
+/*
+ * Helper function for ocfs2_add_branch() and ocfs2_shift_tree_depth().
+ *
+ * Returns the sum of the rightmost extent rec logical offset and
+ * cluster count.
+ *
+ * ocfs2_add_branch() uses this to determine what logical cluster
+ * value should be populated into the leftmost new branch records.
+ *
+ * ocfs2_shift_tree_depth() uses this to determine the # clusters
+ * value for the new topmost tree record.
+ */
+static inline u32 ocfs2_sum_rightmost_rec(struct ocfs2_extent_list  *el)
+{
+	int i;
+
+	i = le16_to_cpu(el->l_next_free_rec) - 1;
+
+	return le32_to_cpu(el->l_recs[i].e_cpos) +
+		ocfs2_rec_clusters(el, &el->l_recs[i]);
+}
+
+/*
+ * Change range of the branches in the right most path according to the leaf
+ * extent block's rightmost record.
+ */
+static int ocfs2_adjust_rightmost_branch(handle_t *handle,
+					 struct ocfs2_extent_tree *et)
+{
+	int status;
+	struct ocfs2_path *path = NULL;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_extent_rec *rec;
+
+	path = ocfs2_new_path_from_et(et);
+	if (!path) {
+		status = -ENOMEM;
+		return status;
+	}
+
+	status = ocfs2_find_path(et->et_ci, path, UINT_MAX);
+	if (status < 0) {
+		mlog_errno(status);
+		goto out;
+	}
+
+	status = ocfs2_extend_trans(handle, path_num_items(path));
+	if (status < 0) {
+		mlog_errno(status);
+		goto out;
+	}
+
+	status = ocfs2_journal_access_path(et->et_ci, handle, path);
+	if (status < 0) {
+		mlog_errno(status);
+		goto out;
+	}
+
+	el = path_leaf_el(path);
+	rec = &el->l_recs[le16_to_cpu(el->l_next_free_rec) - 1];
+
+	ocfs2_adjust_rightmost_records(handle, et, path, rec);
+
+out:
+	ocfs2_free_path(path);
+	return status;
+}
+
+/*
+ * Add an entire tree branch to our inode. eb_bh is the extent block
+ * to start at, if we don't want to start the branch at the root
+ * structure.
+ *
+ * last_eb_bh is required as we have to update it's next_leaf pointer
+ * for the new last extent block.
+ *
+ * the new branch will be 'empty' in the sense that every block will
+ * contain a single record with cluster count == 0.
+ */
+static int ocfs2_add_branch(handle_t *handle,
+			    struct ocfs2_extent_tree *et,
+			    struct buffer_head *eb_bh,
+			    struct buffer_head **last_eb_bh,
+			    struct ocfs2_alloc_context *meta_ac)
+{
+	int status, new_blocks, i, block_given = 0;
+	u64 next_blkno, new_last_eb_blk;
+	struct buffer_head *bh;
+	struct buffer_head **new_eb_bhs = NULL;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list  *eb_el;
+	struct ocfs2_extent_list  *el;
+	u32 new_cpos, root_end;
+
+	BUG_ON(!last_eb_bh || !*last_eb_bh);
+
+	if (eb_bh) {
+		eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+		el = &eb->h_list;
+	} else
+		el = et->et_root_el;
+
+	/* we never add a branch to a leaf. */
+	BUG_ON(!el->l_tree_depth);
+
+	new_blocks = le16_to_cpu(el->l_tree_depth);
+
+	eb = (struct ocfs2_extent_block *)(*last_eb_bh)->b_data;
+	new_cpos = ocfs2_sum_rightmost_rec(&eb->h_list);
+	root_end = ocfs2_sum_rightmost_rec(et->et_root_el);
+
+	/*
+	 * If there is a gap before the root end and the real end
+	 * of the righmost leaf block, we need to remove the gap
+	 * between new_cpos and root_end first so that the tree
+	 * is consistent after we add a new branch(it will start
+	 * from new_cpos).
+	 */
+	if (root_end > new_cpos) {
+		trace_ocfs2_adjust_rightmost_branch(
+			(unsigned long long)
+			ocfs2_metadata_cache_owner(et->et_ci),
+			root_end, new_cpos);
+
+		status = ocfs2_adjust_rightmost_branch(handle, et);
+		if (status) {
+			mlog_errno(status);
+			goto bail;
+		}
+	}
+
+	/* allocate the number of new eb blocks we need */
+	new_eb_bhs = kcalloc(new_blocks, sizeof(struct buffer_head *),
+			     GFP_KERNEL);
+	if (!new_eb_bhs) {
+		status = -ENOMEM;
+		mlog_errno(status);
+		goto bail;
+	}
+
+	/* Firstyly, try to reuse dealloc since we have already estimated how
+	 * many extent blocks we may use.
+	 */
+	if (!ocfs2_is_dealloc_empty(et)) {
+		status = ocfs2_reuse_blk_from_dealloc(handle, et,
+						      new_eb_bhs, new_blocks,
+						      &block_given);
+		if (status < 0) {
+			mlog_errno(status);
+			goto bail;
+		}
+	}
+
+	BUG_ON(block_given > new_blocks);
+
+	if (block_given < new_blocks) {
+		BUG_ON(!meta_ac);
+		status = ocfs2_create_new_meta_bhs(handle, et,
+						   new_blocks - block_given,
+						   meta_ac,
+						   &new_eb_bhs[block_given]);
+		if (status < 0) {
+			mlog_errno(status);
+			goto bail;
+		}
+	}
+
+	/* Note: new_eb_bhs[new_blocks - 1] is the guy which will be
+	 * linked with the rest of the tree.
+	 * conversly, new_eb_bhs[0] is the new bottommost leaf.
+	 *
+	 * when we leave the loop, new_last_eb_blk will point to the
+	 * newest leaf, and next_blkno will point to the topmost extent
+	 * block. */
+	next_blkno = new_last_eb_blk = 0;
+	for(i = 0; i < new_blocks; i++) {
+		bh = new_eb_bhs[i];
+		eb = (struct ocfs2_extent_block *) bh->b_data;
+		/* ocfs2_create_new_meta_bhs() should create it right! */
+		BUG_ON(!OCFS2_IS_VALID_EXTENT_BLOCK(eb));
+		eb_el = &eb->h_list;
+
+		status = ocfs2_journal_access_eb(handle, et->et_ci, bh,
+						 OCFS2_JOURNAL_ACCESS_CREATE);
+		if (status < 0) {
+			mlog_errno(status);
+			goto bail;
+		}
+
+		eb->h_next_leaf_blk = 0;
+		eb_el->l_tree_depth = cpu_to_le16(i);
+		eb_el->l_next_free_rec = cpu_to_le16(1);
+		/*
+		 * This actually counts as an empty extent as
+		 * c_clusters == 0
+		 */
+		eb_el->l_recs[0].e_cpos = cpu_to_le32(new_cpos);
+		eb_el->l_recs[0].e_blkno = cpu_to_le64(next_blkno);
+		/*
+		 * eb_el isn't always an interior node, but even leaf
+		 * nodes want a zero'd flags and reserved field so
+		 * this gets the whole 32 bits regardless of use.
+		 */
+		eb_el->l_recs[0].e_int_clusters = cpu_to_le32(0);
+		if (!eb_el->l_tree_depth)
+			new_last_eb_blk = le64_to_cpu(eb->h_blkno);
+
+		ocfs2_journal_dirty(handle, bh);
+		next_blkno = le64_to_cpu(eb->h_blkno);
+	}
+
+	/* This is a bit hairy. We want to update up to three blocks
+	 * here without leaving any of them in an inconsistent state
+	 * in case of error. We don't have to worry about
+	 * journal_dirty erroring as it won't unless we've aborted the
+	 * handle (in which case we would never be here) so reserving
+	 * the write with journal_access is all we need to do. */
+	status = ocfs2_journal_access_eb(handle, et->et_ci, *last_eb_bh,
+					 OCFS2_JOURNAL_ACCESS_WRITE);
+	if (status < 0) {
+		mlog_errno(status);
+		goto bail;
+	}
+	status = ocfs2_et_root_journal_access(handle, et,
+					      OCFS2_JOURNAL_ACCESS_WRITE);
+	if (status < 0) {
+		mlog_errno(status);
+		goto bail;
+	}
+	if (eb_bh) {
+		status = ocfs2_journal_access_eb(handle, et->et_ci, eb_bh,
+						 OCFS2_JOURNAL_ACCESS_WRITE);
+		if (status < 0) {
+			mlog_errno(status);
+			goto bail;
+		}
+	}
+
+	/* Link the new branch into the rest of the tree (el will
+	 * either be on the root_bh, or the extent block passed in. */
+	i = le16_to_cpu(el->l_next_free_rec);
+	el->l_recs[i].e_blkno = cpu_to_le64(next_blkno);
+	el->l_recs[i].e_cpos = cpu_to_le32(new_cpos);
+	el->l_recs[i].e_int_clusters = 0;
+	le16_add_cpu(&el->l_next_free_rec, 1);
+
+	/* fe needs a new last extent block pointer, as does the
+	 * next_leaf on the previously last-extent-block. */
+	ocfs2_et_set_last_eb_blk(et, new_last_eb_blk);
+
+	eb = (struct ocfs2_extent_block *) (*last_eb_bh)->b_data;
+	eb->h_next_leaf_blk = cpu_to_le64(new_last_eb_blk);
+
+	ocfs2_journal_dirty(handle, *last_eb_bh);
+	ocfs2_journal_dirty(handle, et->et_root_bh);
+	if (eb_bh)
+		ocfs2_journal_dirty(handle, eb_bh);
+
+	/*
+	 * Some callers want to track the rightmost leaf so pass it
+	 * back here.
+	 */
+	brelse(*last_eb_bh);
+	get_bh(new_eb_bhs[0]);
+	*last_eb_bh = new_eb_bhs[0];
+
+	status = 0;
+bail:
+	if (new_eb_bhs) {
+		for (i = 0; i < new_blocks; i++)
+			brelse(new_eb_bhs[i]);
+		kfree(new_eb_bhs);
+	}
+
+	return status;
+}
+
+/*
+ * adds another level to the allocation tree.
+ * returns back the new extent block so you can add a branch to it
+ * after this call.
+ */
+static int ocfs2_shift_tree_depth(handle_t *handle,
+				  struct ocfs2_extent_tree *et,
+				  struct ocfs2_alloc_context *meta_ac,
+				  struct buffer_head **ret_new_eb_bh)
+{
+	int status, i, block_given = 0;
+	u32 new_clusters;
+	struct buffer_head *new_eb_bh = NULL;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list  *root_el;
+	struct ocfs2_extent_list  *eb_el;
+
+	if (!ocfs2_is_dealloc_empty(et)) {
+		status = ocfs2_reuse_blk_from_dealloc(handle, et,
+						      &new_eb_bh, 1,
+						      &block_given);
+	} else if (meta_ac) {
+		status = ocfs2_create_new_meta_bhs(handle, et, 1, meta_ac,
+						   &new_eb_bh);
+
+	} else {
+		BUG();
+	}
+
+	if (status < 0) {
+		mlog_errno(status);
+		goto bail;
+	}
+
+	eb = (struct ocfs2_extent_block *) new_eb_bh->b_data;
+	/* ocfs2_create_new_meta_bhs() should create it right! */
+	BUG_ON(!OCFS2_IS_VALID_EXTENT_BLOCK(eb));
+
+	eb_el = &eb->h_list;
+	root_el = et->et_root_el;
+
+	status = ocfs2_journal_access_eb(handle, et->et_ci, new_eb_bh,
+					 OCFS2_JOURNAL_ACCESS_CREATE);
+	if (status < 0) {
+		mlog_errno(status);
+		goto bail;
+	}
+
+	/* copy the root extent list data into the new extent block */
+	eb_el->l_tree_depth = root_el->l_tree_depth;
+	eb_el->l_next_free_rec = root_el->l_next_free_rec;
+	for (i = 0; i < le16_to_cpu(root_el->l_next_free_rec); i++)
+		eb_el->l_recs[i] = root_el->l_recs[i];
+
+	ocfs2_journal_dirty(handle, new_eb_bh);
+
+	status = ocfs2_et_root_journal_access(handle, et,
+					      OCFS2_JOURNAL_ACCESS_WRITE);
+	if (status < 0) {
+		mlog_errno(status);
+		goto bail;
+	}
+
+	new_clusters = ocfs2_sum_rightmost_rec(eb_el);
+
+	/* update root_bh now */
+	le16_add_cpu(&root_el->l_tree_depth, 1);
+	root_el->l_recs[0].e_cpos = 0;
+	root_el->l_recs[0].e_blkno = eb->h_blkno;
+	root_el->l_recs[0].e_int_clusters = cpu_to_le32(new_clusters);
+	for (i = 1; i < le16_to_cpu(root_el->l_next_free_rec); i++)
+		memset(&root_el->l_recs[i], 0, sizeof(struct ocfs2_extent_rec));
+	root_el->l_next_free_rec = cpu_to_le16(1);
+
+	/* If this is our 1st tree depth shift, then last_eb_blk
+	 * becomes the allocated extent block */
+	if (root_el->l_tree_depth == cpu_to_le16(1))
+		ocfs2_et_set_last_eb_blk(et, le64_to_cpu(eb->h_blkno));
+
+	ocfs2_journal_dirty(handle, et->et_root_bh);
+
+	*ret_new_eb_bh = new_eb_bh;
+	new_eb_bh = NULL;
+	status = 0;
+bail:
+	brelse(new_eb_bh);
+
+	return status;
+}
+
+/*
+ * Should only be called when there is no space left in any of the
+ * leaf nodes. What we want to do is find the lowest tree depth
+ * non-leaf extent block with room for new records. There are three
+ * valid results of this search:
+ *
+ * 1) a lowest extent block is found, then we pass it back in
+ *    *lowest_eb_bh and return '0'
+ *
+ * 2) the search fails to find anything, but the root_el has room. We
+ *    pass NULL back in *lowest_eb_bh, but still return '0'
+ *
+ * 3) the search fails to find anything AND the root_el is full, in
+ *    which case we return > 0
+ *
+ * return status < 0 indicates an error.
+ */
+static int ocfs2_find_branch_target(struct ocfs2_extent_tree *et,
+				    struct buffer_head **target_bh)
+{
+	int status = 0, i;
+	u64 blkno;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list  *el;
+	struct buffer_head *bh = NULL;
+	struct buffer_head *lowest_bh = NULL;
+
+	*target_bh = NULL;
+
+	el = et->et_root_el;
+
+	while(le16_to_cpu(el->l_tree_depth) > 1) {
+		if (le16_to_cpu(el->l_next_free_rec) == 0) {
+			status = ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+					"Owner %llu has empty extent list (next_free_rec == 0)\n",
+					(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci));
+			goto bail;
+		}
+		i = le16_to_cpu(el->l_next_free_rec) - 1;
+		blkno = le64_to_cpu(el->l_recs[i].e_blkno);
+		if (!blkno) {
+			status = ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+					"Owner %llu has extent list where extent # %d has no physical block start\n",
+					(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci), i);
+			goto bail;
+		}
+
+		brelse(bh);
+		bh = NULL;
+
+		status = ocfs2_read_extent_block(et->et_ci, blkno, &bh);
+		if (status < 0) {
+			mlog_errno(status);
+			goto bail;
+		}
+
+		eb = (struct ocfs2_extent_block *) bh->b_data;
+		el = &eb->h_list;
+
+		if (le16_to_cpu(el->l_next_free_rec) <
+		    le16_to_cpu(el->l_count)) {
+			brelse(lowest_bh);
+			lowest_bh = bh;
+			get_bh(lowest_bh);
+		}
+	}
+
+	/* If we didn't find one and the fe doesn't have any room,
+	 * then return '1' */
+	el = et->et_root_el;
+	if (!lowest_bh && (el->l_next_free_rec == el->l_count))
+		status = 1;
+
+	*target_bh = lowest_bh;
+bail:
+	brelse(bh);
+
+	return status;
+}
+
+/*
+ * Grow a b-tree so that it has more records.
+ *
+ * We might shift the tree depth in which case existing paths should
+ * be considered invalid.
+ *
+ * Tree depth after the grow is returned via *final_depth.
+ *
+ * *last_eb_bh will be updated by ocfs2_add_branch().
+ */
+static int ocfs2_grow_tree(handle_t *handle, struct ocfs2_extent_tree *et,
+			   int *final_depth, struct buffer_head **last_eb_bh,
+			   struct ocfs2_alloc_context *meta_ac)
+{
+	int ret, shift;
+	struct ocfs2_extent_list *el = et->et_root_el;
+	int depth = le16_to_cpu(el->l_tree_depth);
+	struct buffer_head *bh = NULL;
+
+	BUG_ON(meta_ac == NULL && ocfs2_is_dealloc_empty(et));
+
+	shift = ocfs2_find_branch_target(et, &bh);
+	if (shift < 0) {
+		ret = shift;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/* We traveled all the way to the bottom of the allocation tree
+	 * and didn't find room for any more extents - we need to add
+	 * another tree level */
+	if (shift) {
+		BUG_ON(bh);
+		trace_ocfs2_grow_tree(
+			(unsigned long long)
+			ocfs2_metadata_cache_owner(et->et_ci),
+			depth);
+
+		/* ocfs2_shift_tree_depth will return us a buffer with
+		 * the new extent block (so we can pass that to
+		 * ocfs2_add_branch). */
+		ret = ocfs2_shift_tree_depth(handle, et, meta_ac, &bh);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto out;
+		}
+		depth++;
+		if (depth == 1) {
+			/*
+			 * Special case: we have room now if we shifted from
+			 * tree_depth 0, so no more work needs to be done.
+			 *
+			 * We won't be calling add_branch, so pass
+			 * back *last_eb_bh as the new leaf. At depth
+			 * zero, it should always be null so there's
+			 * no reason to brelse.
+			 */
+			BUG_ON(*last_eb_bh);
+			get_bh(bh);
+			*last_eb_bh = bh;
+			goto out;
+		}
+	}
+
+	/* call ocfs2_add_branch to add the final part of the tree with
+	 * the new data. */
+	ret = ocfs2_add_branch(handle, et, bh, last_eb_bh,
+			       meta_ac);
+	if (ret < 0)
+		mlog_errno(ret);
+
+out:
+	if (final_depth)
+		*final_depth = depth;
+	brelse(bh);
+	return ret;
+}
+
+/*
+ * This function will discard the rightmost extent record.
+ */
+static void ocfs2_shift_records_right(struct ocfs2_extent_list *el)
+{
+	int next_free = le16_to_cpu(el->l_next_free_rec);
+	int count = le16_to_cpu(el->l_count);
+	unsigned int num_bytes;
+
+	BUG_ON(!next_free);
+	/* This will cause us to go off the end of our extent list. */
+	BUG_ON(next_free >= count);
+
+	num_bytes = sizeof(struct ocfs2_extent_rec) * next_free;
+
+	memmove(&el->l_recs[1], &el->l_recs[0], num_bytes);
+}
+
+static void ocfs2_rotate_leaf(struct ocfs2_extent_list *el,
+			      struct ocfs2_extent_rec *insert_rec)
+{
+	int i, insert_index, next_free, has_empty, num_bytes;
+	u32 insert_cpos = le32_to_cpu(insert_rec->e_cpos);
+	struct ocfs2_extent_rec *rec;
+
+	next_free = le16_to_cpu(el->l_next_free_rec);
+	has_empty = ocfs2_is_empty_extent(&el->l_recs[0]);
+
+	BUG_ON(!next_free);
+
+	/* The tree code before us didn't allow enough room in the leaf. */
+	BUG_ON(el->l_next_free_rec == el->l_count && !has_empty);
+
+	/*
+	 * The easiest way to approach this is to just remove the
+	 * empty extent and temporarily decrement next_free.
+	 */
+	if (has_empty) {
+		/*
+		 * If next_free was 1 (only an empty extent), this
+		 * loop won't execute, which is fine. We still want
+		 * the decrement above to happen.
+		 */
+		for(i = 0; i < (next_free - 1); i++)
+			el->l_recs[i] = el->l_recs[i+1];
+
+		next_free--;
+	}
+
+	/*
+	 * Figure out what the new record index should be.
+	 */
+	for(i = 0; i < next_free; i++) {
+		rec = &el->l_recs[i];
+
+		if (insert_cpos < le32_to_cpu(rec->e_cpos))
+			break;
+	}
+	insert_index = i;
+
+	trace_ocfs2_rotate_leaf(insert_cpos, insert_index,
+				has_empty, next_free,
+				le16_to_cpu(el->l_count));
+
+	BUG_ON(insert_index < 0);
+	BUG_ON(insert_index >= le16_to_cpu(el->l_count));
+	BUG_ON(insert_index > next_free);
+
+	/*
+	 * No need to memmove if we're just adding to the tail.
+	 */
+	if (insert_index != next_free) {
+		BUG_ON(next_free >= le16_to_cpu(el->l_count));
+
+		num_bytes = next_free - insert_index;
+		num_bytes *= sizeof(struct ocfs2_extent_rec);
+		memmove(&el->l_recs[insert_index + 1],
+			&el->l_recs[insert_index],
+			num_bytes);
+	}
+
+	/*
+	 * Either we had an empty extent, and need to re-increment or
+	 * there was no empty extent on a non full rightmost leaf node,
+	 * in which case we still need to increment.
+	 */
+	next_free++;
+	el->l_next_free_rec = cpu_to_le16(next_free);
+	/*
+	 * Make sure none of the math above just messed up our tree.
+	 */
+	BUG_ON(le16_to_cpu(el->l_next_free_rec) > le16_to_cpu(el->l_count));
+
+	el->l_recs[insert_index] = *insert_rec;
+
+}
+
+static void ocfs2_remove_empty_extent(struct ocfs2_extent_list *el)
+{
+	int size, num_recs = le16_to_cpu(el->l_next_free_rec);
+
+	BUG_ON(num_recs == 0);
+
+	if (ocfs2_is_empty_extent(&el->l_recs[0])) {
+		num_recs--;
+		size = num_recs * sizeof(struct ocfs2_extent_rec);
+		memmove(&el->l_recs[0], &el->l_recs[1], size);
+		memset(&el->l_recs[num_recs], 0,
+		       sizeof(struct ocfs2_extent_rec));
+		el->l_next_free_rec = cpu_to_le16(num_recs);
+	}
+}
+
+/*
+ * Create an empty extent record .
+ *
+ * l_next_free_rec may be updated.
+ *
+ * If an empty extent already exists do nothing.
+ */
+static void ocfs2_create_empty_extent(struct ocfs2_extent_list *el)
+{
+	int next_free = le16_to_cpu(el->l_next_free_rec);
+
+	BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
+
+	if (next_free == 0)
+		goto set_and_inc;
+
+	if (ocfs2_is_empty_extent(&el->l_recs[0]))
+		return;
+
+	mlog_bug_on_msg(el->l_count == el->l_next_free_rec,
+			"Asked to create an empty extent in a full list:\n"
+			"count = %u, tree depth = %u",
+			le16_to_cpu(el->l_count),
+			le16_to_cpu(el->l_tree_depth));
+
+	ocfs2_shift_records_right(el);
+
+set_and_inc:
+	le16_add_cpu(&el->l_next_free_rec, 1);
+	memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
+}
+
+/*
+ * For a rotation which involves two leaf nodes, the "root node" is
+ * the lowest level tree node which contains a path to both leafs. This
+ * resulting set of information can be used to form a complete "subtree"
+ *
+ * This function is passed two full paths from the dinode down to a
+ * pair of adjacent leaves. It's task is to figure out which path
+ * index contains the subtree root - this can be the root index itself
+ * in a worst-case rotation.
+ *
+ * The array index of the subtree root is passed back.
+ */
+int ocfs2_find_subtree_root(struct ocfs2_extent_tree *et,
+			    struct ocfs2_path *left,
+			    struct ocfs2_path *right)
+{
+	int i = 0;
+
+	/*
+	 * Check that the caller passed in two paths from the same tree.
+	 */
+	BUG_ON(path_root_bh(left) != path_root_bh(right));
+
+	do {
+		i++;
+
+		/*
+		 * The caller didn't pass two adjacent paths.
+		 */
+		mlog_bug_on_msg(i > left->p_tree_depth,
+				"Owner %llu, left depth %u, right depth %u\n"
+				"left leaf blk %llu, right leaf blk %llu\n",
+				(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+				left->p_tree_depth, right->p_tree_depth,
+				(unsigned long long)path_leaf_bh(left)->b_blocknr,
+				(unsigned long long)path_leaf_bh(right)->b_blocknr);
+	} while (left->p_node[i].bh->b_blocknr ==
+		 right->p_node[i].bh->b_blocknr);
+
+	return i - 1;
+}
+
+typedef void (path_insert_t)(void *, struct buffer_head *);
+
+/*
+ * Traverse a btree path in search of cpos, starting at root_el.
+ *
+ * This code can be called with a cpos larger than the tree, in which
+ * case it will return the rightmost path.
+ */
+static int __ocfs2_find_path(struct ocfs2_caching_info *ci,
+			     struct ocfs2_extent_list *root_el, u32 cpos,
+			     path_insert_t *func, void *data)
+{
+	int i, ret = 0;
+	u32 range;
+	u64 blkno;
+	struct buffer_head *bh = NULL;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_extent_rec *rec;
+
+	el = root_el;
+	while (el->l_tree_depth) {
+		if (le16_to_cpu(el->l_next_free_rec) == 0) {
+			ocfs2_error(ocfs2_metadata_cache_get_super(ci),
+				    "Owner %llu has empty extent list at depth %u\n",
+				    (unsigned long long)ocfs2_metadata_cache_owner(ci),
+				    le16_to_cpu(el->l_tree_depth));
+			ret = -EROFS;
+			goto out;
+
+		}
+
+		for(i = 0; i < le16_to_cpu(el->l_next_free_rec) - 1; i++) {
+			rec = &el->l_recs[i];
+
+			/*
+			 * In the case that cpos is off the allocation
+			 * tree, this should just wind up returning the
+			 * rightmost record.
+			 */
+			range = le32_to_cpu(rec->e_cpos) +
+				ocfs2_rec_clusters(el, rec);
+			if (cpos >= le32_to_cpu(rec->e_cpos) && cpos < range)
+			    break;
+		}
+
+		blkno = le64_to_cpu(el->l_recs[i].e_blkno);
+		if (blkno == 0) {
+			ocfs2_error(ocfs2_metadata_cache_get_super(ci),
+				    "Owner %llu has bad blkno in extent list at depth %u (index %d)\n",
+				    (unsigned long long)ocfs2_metadata_cache_owner(ci),
+				    le16_to_cpu(el->l_tree_depth), i);
+			ret = -EROFS;
+			goto out;
+		}
+
+		brelse(bh);
+		bh = NULL;
+		ret = ocfs2_read_extent_block(ci, blkno, &bh);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		eb = (struct ocfs2_extent_block *) bh->b_data;
+		el = &eb->h_list;
+
+		if (le16_to_cpu(el->l_next_free_rec) >
+		    le16_to_cpu(el->l_count)) {
+			ocfs2_error(ocfs2_metadata_cache_get_super(ci),
+				    "Owner %llu has bad count in extent list at block %llu (next free=%u, count=%u)\n",
+				    (unsigned long long)ocfs2_metadata_cache_owner(ci),
+				    (unsigned long long)bh->b_blocknr,
+				    le16_to_cpu(el->l_next_free_rec),
+				    le16_to_cpu(el->l_count));
+			ret = -EROFS;
+			goto out;
+		}
+
+		if (func)
+			func(data, bh);
+	}
+
+out:
+	/*
+	 * Catch any trailing bh that the loop didn't handle.
+	 */
+	brelse(bh);
+
+	return ret;
+}
+
+/*
+ * Given an initialized path (that is, it has a valid root extent
+ * list), this function will traverse the btree in search of the path
+ * which would contain cpos.
+ *
+ * The path traveled is recorded in the path structure.
+ *
+ * Note that this will not do any comparisons on leaf node extent
+ * records, so it will work fine in the case that we just added a tree
+ * branch.
+ */
+struct find_path_data {
+	int index;
+	struct ocfs2_path *path;
+};
+static void find_path_ins(void *data, struct buffer_head *bh)
+{
+	struct find_path_data *fp = data;
+
+	get_bh(bh);
+	ocfs2_path_insert_eb(fp->path, fp->index, bh);
+	fp->index++;
+}
+int ocfs2_find_path(struct ocfs2_caching_info *ci,
+		    struct ocfs2_path *path, u32 cpos)
+{
+	struct find_path_data data;
+
+	data.index = 1;
+	data.path = path;
+	return __ocfs2_find_path(ci, path_root_el(path), cpos,
+				 find_path_ins, &data);
+}
+
+static void find_leaf_ins(void *data, struct buffer_head *bh)
+{
+	struct ocfs2_extent_block *eb =(struct ocfs2_extent_block *)bh->b_data;
+	struct ocfs2_extent_list *el = &eb->h_list;
+	struct buffer_head **ret = data;
+
+	/* We want to retain only the leaf block. */
+	if (le16_to_cpu(el->l_tree_depth) == 0) {
+		get_bh(bh);
+		*ret = bh;
+	}
+}
+/*
+ * Find the leaf block in the tree which would contain cpos. No
+ * checking of the actual leaf is done.
+ *
+ * Some paths want to call this instead of allocating a path structure
+ * and calling ocfs2_find_path().
+ *
+ * This function doesn't handle non btree extent lists.
+ */
+int ocfs2_find_leaf(struct ocfs2_caching_info *ci,
+		    struct ocfs2_extent_list *root_el, u32 cpos,
+		    struct buffer_head **leaf_bh)
+{
+	int ret;
+	struct buffer_head *bh = NULL;
+
+	ret = __ocfs2_find_path(ci, root_el, cpos, find_leaf_ins, &bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	*leaf_bh = bh;
+out:
+	return ret;
+}
+
+/*
+ * Adjust the adjacent records (left_rec, right_rec) involved in a rotation.
+ *
+ * Basically, we've moved stuff around at the bottom of the tree and
+ * we need to fix up the extent records above the changes to reflect
+ * the new changes.
+ *
+ * left_rec: the record on the left.
+ * right_rec: the record to the right of left_rec
+ * right_child_el: is the child list pointed to by right_rec
+ *
+ * By definition, this only works on interior nodes.
+ */
+static void ocfs2_adjust_adjacent_records(struct ocfs2_extent_rec *left_rec,
+				  struct ocfs2_extent_rec *right_rec,
+				  struct ocfs2_extent_list *right_child_el)
+{
+	u32 left_clusters, right_end;
+
+	/*
+	 * Interior nodes never have holes. Their cpos is the cpos of
+	 * the leftmost record in their child list. Their cluster
+	 * count covers the full theoretical range of their child list
+	 * - the range between their cpos and the cpos of the record
+	 * immediately to their right.
+	 */
+	left_clusters = le32_to_cpu(right_child_el->l_recs[0].e_cpos);
+	if (!ocfs2_rec_clusters(right_child_el, &right_child_el->l_recs[0])) {
+		BUG_ON(right_child_el->l_tree_depth);
+		BUG_ON(le16_to_cpu(right_child_el->l_next_free_rec) <= 1);
+		left_clusters = le32_to_cpu(right_child_el->l_recs[1].e_cpos);
+	}
+	left_clusters -= le32_to_cpu(left_rec->e_cpos);
+	left_rec->e_int_clusters = cpu_to_le32(left_clusters);
+
+	/*
+	 * Calculate the rightmost cluster count boundary before
+	 * moving cpos - we will need to adjust clusters after
+	 * updating e_cpos to keep the same highest cluster count.
+	 */
+	right_end = le32_to_cpu(right_rec->e_cpos);
+	right_end += le32_to_cpu(right_rec->e_int_clusters);
+
+	right_rec->e_cpos = left_rec->e_cpos;
+	le32_add_cpu(&right_rec->e_cpos, left_clusters);
+
+	right_end -= le32_to_cpu(right_rec->e_cpos);
+	right_rec->e_int_clusters = cpu_to_le32(right_end);
+}
+
+/*
+ * Adjust the adjacent root node records involved in a
+ * rotation. left_el_blkno is passed in as a key so that we can easily
+ * find it's index in the root list.
+ */
+static void ocfs2_adjust_root_records(struct ocfs2_extent_list *root_el,
+				      struct ocfs2_extent_list *left_el,
+				      struct ocfs2_extent_list *right_el,
+				      u64 left_el_blkno)
+{
+	int i;
+
+	BUG_ON(le16_to_cpu(root_el->l_tree_depth) <=
+	       le16_to_cpu(left_el->l_tree_depth));
+
+	for(i = 0; i < le16_to_cpu(root_el->l_next_free_rec) - 1; i++) {
+		if (le64_to_cpu(root_el->l_recs[i].e_blkno) == left_el_blkno)
+			break;
+	}
+
+	/*
+	 * The path walking code should have never returned a root and
+	 * two paths which are not adjacent.
+	 */
+	BUG_ON(i >= (le16_to_cpu(root_el->l_next_free_rec) - 1));
+
+	ocfs2_adjust_adjacent_records(&root_el->l_recs[i],
+				      &root_el->l_recs[i + 1], right_el);
+}
+
+/*
+ * We've changed a leaf block (in right_path) and need to reflect that
+ * change back up the subtree.
+ *
+ * This happens in multiple places:
+ *   - When we've moved an extent record from the left path leaf to the right
+ *     path leaf to make room for an empty extent in the left path leaf.
+ *   - When our insert into the right path leaf is at the leftmost edge
+ *     and requires an update of the path immediately to it's left. This
+ *     can occur at the end of some types of rotation and appending inserts.
+ *   - When we've adjusted the last extent record in the left path leaf and the
+ *     1st extent record in the right path leaf during cross extent block merge.
+ */
+static void ocfs2_complete_edge_insert(handle_t *handle,
+				       struct ocfs2_path *left_path,
+				       struct ocfs2_path *right_path,
+				       int subtree_index)
+{
+	int i, idx;
+	struct ocfs2_extent_list *el, *left_el, *right_el;
+	struct ocfs2_extent_rec *left_rec, *right_rec;
+	struct buffer_head *root_bh;
+
+	/*
+	 * Update the counts and position values within all the
+	 * interior nodes to reflect the leaf rotation we just did.
+	 *
+	 * The root node is handled below the loop.
+	 *
+	 * We begin the loop with right_el and left_el pointing to the
+	 * leaf lists and work our way up.
+	 *
+	 * NOTE: within this loop, left_el and right_el always refer
+	 * to the *child* lists.
+	 */
+	left_el = path_leaf_el(left_path);
+	right_el = path_leaf_el(right_path);
+	for(i = left_path->p_tree_depth - 1; i > subtree_index; i--) {
+		trace_ocfs2_complete_edge_insert(i);
+
+		/*
+		 * One nice property of knowing that all of these
+		 * nodes are below the root is that we only deal with
+		 * the leftmost right node record and the rightmost
+		 * left node record.
+		 */
+		el = left_path->p_node[i].el;
+		idx = le16_to_cpu(left_el->l_next_free_rec) - 1;
+		left_rec = &el->l_recs[idx];
+
+		el = right_path->p_node[i].el;
+		right_rec = &el->l_recs[0];
+
+		ocfs2_adjust_adjacent_records(left_rec, right_rec, right_el);
+
+		ocfs2_journal_dirty(handle, left_path->p_node[i].bh);
+		ocfs2_journal_dirty(handle, right_path->p_node[i].bh);
+
+		/*
+		 * Setup our list pointers now so that the current
+		 * parents become children in the next iteration.
+		 */
+		left_el = left_path->p_node[i].el;
+		right_el = right_path->p_node[i].el;
+	}
+
+	/*
+	 * At the root node, adjust the two adjacent records which
+	 * begin our path to the leaves.
+	 */
+
+	el = left_path->p_node[subtree_index].el;
+	left_el = left_path->p_node[subtree_index + 1].el;
+	right_el = right_path->p_node[subtree_index + 1].el;
+
+	ocfs2_adjust_root_records(el, left_el, right_el,
+				  left_path->p_node[subtree_index + 1].bh->b_blocknr);
+
+	root_bh = left_path->p_node[subtree_index].bh;
+
+	ocfs2_journal_dirty(handle, root_bh);
+}
+
+static int ocfs2_rotate_subtree_right(handle_t *handle,
+				      struct ocfs2_extent_tree *et,
+				      struct ocfs2_path *left_path,
+				      struct ocfs2_path *right_path,
+				      int subtree_index)
+{
+	int ret, i;
+	struct buffer_head *right_leaf_bh;
+	struct buffer_head *left_leaf_bh = NULL;
+	struct buffer_head *root_bh;
+	struct ocfs2_extent_list *right_el, *left_el;
+	struct ocfs2_extent_rec move_rec;
+
+	left_leaf_bh = path_leaf_bh(left_path);
+	left_el = path_leaf_el(left_path);
+
+	if (left_el->l_next_free_rec != left_el->l_count) {
+		ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+			    "Inode %llu has non-full interior leaf node %llu (next free = %u)\n",
+			    (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+			    (unsigned long long)left_leaf_bh->b_blocknr,
+			    le16_to_cpu(left_el->l_next_free_rec));
+		return -EROFS;
+	}
+
+	/*
+	 * This extent block may already have an empty record, so we
+	 * return early if so.
+	 */
+	if (ocfs2_is_empty_extent(&left_el->l_recs[0]))
+		return 0;
+
+	root_bh = left_path->p_node[subtree_index].bh;
+	BUG_ON(root_bh != right_path->p_node[subtree_index].bh);
+
+	ret = ocfs2_path_bh_journal_access(handle, et->et_ci, right_path,
+					   subtree_index);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	for(i = subtree_index + 1; i < path_num_items(right_path); i++) {
+		ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
+						   right_path, i);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
+						   left_path, i);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+	right_leaf_bh = path_leaf_bh(right_path);
+	right_el = path_leaf_el(right_path);
+
+	/* This is a code error, not a disk corruption. */
+	mlog_bug_on_msg(!right_el->l_next_free_rec, "Inode %llu: Rotate fails "
+			"because rightmost leaf block %llu is empty\n",
+			(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+			(unsigned long long)right_leaf_bh->b_blocknr);
+
+	ocfs2_create_empty_extent(right_el);
+
+	ocfs2_journal_dirty(handle, right_leaf_bh);
+
+	/* Do the copy now. */
+	i = le16_to_cpu(left_el->l_next_free_rec) - 1;
+	move_rec = left_el->l_recs[i];
+	right_el->l_recs[0] = move_rec;
+
+	/*
+	 * Clear out the record we just copied and shift everything
+	 * over, leaving an empty extent in the left leaf.
+	 *
+	 * We temporarily subtract from next_free_rec so that the
+	 * shift will lose the tail record (which is now defunct).
+	 */
+	le16_add_cpu(&left_el->l_next_free_rec, -1);
+	ocfs2_shift_records_right(left_el);
+	memset(&left_el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
+	le16_add_cpu(&left_el->l_next_free_rec, 1);
+
+	ocfs2_journal_dirty(handle, left_leaf_bh);
+
+	ocfs2_complete_edge_insert(handle, left_path, right_path,
+				   subtree_index);
+
+out:
+	return ret;
+}
+
+/*
+ * Given a full path, determine what cpos value would return us a path
+ * containing the leaf immediately to the left of the current one.
+ *
+ * Will return zero if the path passed in is already the leftmost path.
+ */
+int ocfs2_find_cpos_for_left_leaf(struct super_block *sb,
+				  struct ocfs2_path *path, u32 *cpos)
+{
+	int i, j, ret = 0;
+	u64 blkno;
+	struct ocfs2_extent_list *el;
+
+	BUG_ON(path->p_tree_depth == 0);
+
+	*cpos = 0;
+
+	blkno = path_leaf_bh(path)->b_blocknr;
+
+	/* Start at the tree node just above the leaf and work our way up. */
+	i = path->p_tree_depth - 1;
+	while (i >= 0) {
+		el = path->p_node[i].el;
+
+		/*
+		 * Find the extent record just before the one in our
+		 * path.
+		 */
+		for(j = 0; j < le16_to_cpu(el->l_next_free_rec); j++) {
+			if (le64_to_cpu(el->l_recs[j].e_blkno) == blkno) {
+				if (j == 0) {
+					if (i == 0) {
+						/*
+						 * We've determined that the
+						 * path specified is already
+						 * the leftmost one - return a
+						 * cpos of zero.
+						 */
+						goto out;
+					}
+					/*
+					 * The leftmost record points to our
+					 * leaf - we need to travel up the
+					 * tree one level.
+					 */
+					goto next_node;
+				}
+
+				*cpos = le32_to_cpu(el->l_recs[j - 1].e_cpos);
+				*cpos = *cpos + ocfs2_rec_clusters(el,
+							   &el->l_recs[j - 1]);
+				*cpos = *cpos - 1;
+				goto out;
+			}
+		}
+
+		/*
+		 * If we got here, we never found a valid node where
+		 * the tree indicated one should be.
+		 */
+		ocfs2_error(sb, "Invalid extent tree at extent block %llu\n",
+			    (unsigned long long)blkno);
+		ret = -EROFS;
+		goto out;
+
+next_node:
+		blkno = path->p_node[i].bh->b_blocknr;
+		i--;
+	}
+
+out:
+	return ret;
+}
+
+/*
+ * Extend the transaction by enough credits to complete the rotation,
+ * and still leave at least the original number of credits allocated
+ * to this transaction.
+ */
+static int ocfs2_extend_rotate_transaction(handle_t *handle, int subtree_depth,
+					   int op_credits,
+					   struct ocfs2_path *path)
+{
+	int ret = 0;
+	int credits = (path->p_tree_depth - subtree_depth) * 2 + 1 + op_credits;
+
+	if (jbd2_handle_buffer_credits(handle) < credits)
+		ret = ocfs2_extend_trans(handle,
+				credits - jbd2_handle_buffer_credits(handle));
+
+	return ret;
+}
+
+/*
+ * Trap the case where we're inserting into the theoretical range past
+ * the _actual_ left leaf range. Otherwise, we'll rotate a record
+ * whose cpos is less than ours into the right leaf.
+ *
+ * It's only necessary to look at the rightmost record of the left
+ * leaf because the logic that calls us should ensure that the
+ * theoretical ranges in the path components above the leaves are
+ * correct.
+ */
+static int ocfs2_rotate_requires_path_adjustment(struct ocfs2_path *left_path,
+						 u32 insert_cpos)
+{
+	struct ocfs2_extent_list *left_el;
+	struct ocfs2_extent_rec *rec;
+	int next_free;
+
+	left_el = path_leaf_el(left_path);
+	next_free = le16_to_cpu(left_el->l_next_free_rec);
+	rec = &left_el->l_recs[next_free - 1];
+
+	if (insert_cpos > le32_to_cpu(rec->e_cpos))
+		return 1;
+	return 0;
+}
+
+static int ocfs2_leftmost_rec_contains(struct ocfs2_extent_list *el, u32 cpos)
+{
+	int next_free = le16_to_cpu(el->l_next_free_rec);
+	unsigned int range;
+	struct ocfs2_extent_rec *rec;
+
+	if (next_free == 0)
+		return 0;
+
+	rec = &el->l_recs[0];
+	if (ocfs2_is_empty_extent(rec)) {
+		/* Empty list. */
+		if (next_free == 1)
+			return 0;
+		rec = &el->l_recs[1];
+	}
+
+	range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
+	if (cpos >= le32_to_cpu(rec->e_cpos) && cpos < range)
+		return 1;
+	return 0;
+}
+
+/*
+ * Rotate all the records in a btree right one record, starting at insert_cpos.
+ *
+ * The path to the rightmost leaf should be passed in.
+ *
+ * The array is assumed to be large enough to hold an entire path (tree depth).
+ *
+ * Upon successful return from this function:
+ *
+ * - The 'right_path' array will contain a path to the leaf block
+ *   whose range contains e_cpos.
+ * - That leaf block will have a single empty extent in list index 0.
+ * - In the case that the rotation requires a post-insert update,
+ *   *ret_left_path will contain a valid path which can be passed to
+ *   ocfs2_insert_path().
+ */
+static int ocfs2_rotate_tree_right(handle_t *handle,
+				   struct ocfs2_extent_tree *et,
+				   enum ocfs2_split_type split,
+				   u32 insert_cpos,
+				   struct ocfs2_path *right_path,
+				   struct ocfs2_path **ret_left_path)
+{
+	int ret, start, orig_credits = jbd2_handle_buffer_credits(handle);
+	u32 cpos;
+	struct ocfs2_path *left_path = NULL;
+	struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
+
+	*ret_left_path = NULL;
+
+	left_path = ocfs2_new_path_from_path(right_path);
+	if (!left_path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_find_cpos_for_left_leaf(sb, right_path, &cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	trace_ocfs2_rotate_tree_right(
+		(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+		insert_cpos, cpos);
+
+	/*
+	 * What we want to do here is:
+	 *
+	 * 1) Start with the rightmost path.
+	 *
+	 * 2) Determine a path to the leaf block directly to the left
+	 *    of that leaf.
+	 *
+	 * 3) Determine the 'subtree root' - the lowest level tree node
+	 *    which contains a path to both leaves.
+	 *
+	 * 4) Rotate the subtree.
+	 *
+	 * 5) Find the next subtree by considering the left path to be
+	 *    the new right path.
+	 *
+	 * The check at the top of this while loop also accepts
+	 * insert_cpos == cpos because cpos is only a _theoretical_
+	 * value to get us the left path - insert_cpos might very well
+	 * be filling that hole.
+	 *
+	 * Stop at a cpos of '0' because we either started at the
+	 * leftmost branch (i.e., a tree with one branch and a
+	 * rotation inside of it), or we've gone as far as we can in
+	 * rotating subtrees.
+	 */
+	while (cpos && insert_cpos <= cpos) {
+		trace_ocfs2_rotate_tree_right(
+			(unsigned long long)
+			ocfs2_metadata_cache_owner(et->et_ci),
+			insert_cpos, cpos);
+
+		ret = ocfs2_find_path(et->et_ci, left_path, cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		mlog_bug_on_msg(path_leaf_bh(left_path) ==
+				path_leaf_bh(right_path),
+				"Owner %llu: error during insert of %u "
+				"(left path cpos %u) results in two identical "
+				"paths ending at %llu\n",
+				(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+				insert_cpos, cpos,
+				(unsigned long long)
+				path_leaf_bh(left_path)->b_blocknr);
+
+		if (split == SPLIT_NONE &&
+		    ocfs2_rotate_requires_path_adjustment(left_path,
+							  insert_cpos)) {
+
+			/*
+			 * We've rotated the tree as much as we
+			 * should. The rest is up to
+			 * ocfs2_insert_path() to complete, after the
+			 * record insertion. We indicate this
+			 * situation by returning the left path.
+			 *
+			 * The reason we don't adjust the records here
+			 * before the record insert is that an error
+			 * later might break the rule where a parent
+			 * record e_cpos will reflect the actual
+			 * e_cpos of the 1st nonempty record of the
+			 * child list.
+			 */
+			*ret_left_path = left_path;
+			goto out_ret_path;
+		}
+
+		start = ocfs2_find_subtree_root(et, left_path, right_path);
+
+		trace_ocfs2_rotate_subtree(start,
+			(unsigned long long)
+			right_path->p_node[start].bh->b_blocknr,
+			right_path->p_tree_depth);
+
+		ret = ocfs2_extend_rotate_transaction(handle, start,
+						      orig_credits, right_path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_rotate_subtree_right(handle, et, left_path,
+						 right_path, start);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		if (split != SPLIT_NONE &&
+		    ocfs2_leftmost_rec_contains(path_leaf_el(right_path),
+						insert_cpos)) {
+			/*
+			 * A rotate moves the rightmost left leaf
+			 * record over to the leftmost right leaf
+			 * slot. If we're doing an extent split
+			 * instead of a real insert, then we have to
+			 * check that the extent to be split wasn't
+			 * just moved over. If it was, then we can
+			 * exit here, passing left_path back -
+			 * ocfs2_split_extent() is smart enough to
+			 * search both leaves.
+			 */
+			*ret_left_path = left_path;
+			goto out_ret_path;
+		}
+
+		/*
+		 * There is no need to re-read the next right path
+		 * as we know that it'll be our current left
+		 * path. Optimize by copying values instead.
+		 */
+		ocfs2_mv_path(right_path, left_path);
+
+		ret = ocfs2_find_cpos_for_left_leaf(sb, right_path, &cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+out:
+	ocfs2_free_path(left_path);
+
+out_ret_path:
+	return ret;
+}
+
+static int ocfs2_update_edge_lengths(handle_t *handle,
+				     struct ocfs2_extent_tree *et,
+				     struct ocfs2_path *path)
+{
+	int i, idx, ret;
+	struct ocfs2_extent_rec *rec;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_extent_block *eb;
+	u32 range;
+
+	ret = ocfs2_journal_access_path(et->et_ci, handle, path);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/* Path should always be rightmost. */
+	eb = (struct ocfs2_extent_block *)path_leaf_bh(path)->b_data;
+	BUG_ON(eb->h_next_leaf_blk != 0ULL);
+
+	el = &eb->h_list;
+	BUG_ON(le16_to_cpu(el->l_next_free_rec) == 0);
+	idx = le16_to_cpu(el->l_next_free_rec) - 1;
+	rec = &el->l_recs[idx];
+	range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
+
+	for (i = 0; i < path->p_tree_depth; i++) {
+		el = path->p_node[i].el;
+		idx = le16_to_cpu(el->l_next_free_rec) - 1;
+		rec = &el->l_recs[idx];
+
+		rec->e_int_clusters = cpu_to_le32(range);
+		le32_add_cpu(&rec->e_int_clusters, -le32_to_cpu(rec->e_cpos));
+
+		ocfs2_journal_dirty(handle, path->p_node[i].bh);
+	}
+out:
+	return ret;
+}
+
+static void ocfs2_unlink_path(handle_t *handle,
+			      struct ocfs2_extent_tree *et,
+			      struct ocfs2_cached_dealloc_ctxt *dealloc,
+			      struct ocfs2_path *path, int unlink_start)
+{
+	int ret, i;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list *el;
+	struct buffer_head *bh;
+
+	for(i = unlink_start; i < path_num_items(path); i++) {
+		bh = path->p_node[i].bh;
+
+		eb = (struct ocfs2_extent_block *)bh->b_data;
+		/*
+		 * Not all nodes might have had their final count
+		 * decremented by the caller - handle this here.
+		 */
+		el = &eb->h_list;
+		if (le16_to_cpu(el->l_next_free_rec) > 1) {
+			mlog(ML_ERROR,
+			     "Inode %llu, attempted to remove extent block "
+			     "%llu with %u records\n",
+			     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+			     (unsigned long long)le64_to_cpu(eb->h_blkno),
+			     le16_to_cpu(el->l_next_free_rec));
+
+			ocfs2_journal_dirty(handle, bh);
+			ocfs2_remove_from_cache(et->et_ci, bh);
+			continue;
+		}
+
+		el->l_next_free_rec = 0;
+		memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
+
+		ocfs2_journal_dirty(handle, bh);
+
+		ret = ocfs2_cache_extent_block_free(dealloc, eb);
+		if (ret)
+			mlog_errno(ret);
+
+		ocfs2_remove_from_cache(et->et_ci, bh);
+	}
+}
+
+static void ocfs2_unlink_subtree(handle_t *handle,
+				 struct ocfs2_extent_tree *et,
+				 struct ocfs2_path *left_path,
+				 struct ocfs2_path *right_path,
+				 int subtree_index,
+				 struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+	int i;
+	struct buffer_head *root_bh = left_path->p_node[subtree_index].bh;
+	struct ocfs2_extent_list *root_el = left_path->p_node[subtree_index].el;
+	struct ocfs2_extent_block *eb;
+
+	eb = (struct ocfs2_extent_block *)right_path->p_node[subtree_index + 1].bh->b_data;
+
+	for(i = 1; i < le16_to_cpu(root_el->l_next_free_rec); i++)
+		if (root_el->l_recs[i].e_blkno == eb->h_blkno)
+			break;
+
+	BUG_ON(i >= le16_to_cpu(root_el->l_next_free_rec));
+
+	memset(&root_el->l_recs[i], 0, sizeof(struct ocfs2_extent_rec));
+	le16_add_cpu(&root_el->l_next_free_rec, -1);
+
+	eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
+	eb->h_next_leaf_blk = 0;
+
+	ocfs2_journal_dirty(handle, root_bh);
+	ocfs2_journal_dirty(handle, path_leaf_bh(left_path));
+
+	ocfs2_unlink_path(handle, et, dealloc, right_path,
+			  subtree_index + 1);
+}
+
+static int ocfs2_rotate_subtree_left(handle_t *handle,
+				     struct ocfs2_extent_tree *et,
+				     struct ocfs2_path *left_path,
+				     struct ocfs2_path *right_path,
+				     int subtree_index,
+				     struct ocfs2_cached_dealloc_ctxt *dealloc,
+				     int *deleted)
+{
+	int ret, i, del_right_subtree = 0, right_has_empty = 0;
+	struct buffer_head *root_bh, *et_root_bh = path_root_bh(right_path);
+	struct ocfs2_extent_list *right_leaf_el, *left_leaf_el;
+	struct ocfs2_extent_block *eb;
+
+	*deleted = 0;
+
+	right_leaf_el = path_leaf_el(right_path);
+	left_leaf_el = path_leaf_el(left_path);
+	root_bh = left_path->p_node[subtree_index].bh;
+	BUG_ON(root_bh != right_path->p_node[subtree_index].bh);
+
+	if (!ocfs2_is_empty_extent(&left_leaf_el->l_recs[0]))
+		return 0;
+
+	eb = (struct ocfs2_extent_block *)path_leaf_bh(right_path)->b_data;
+	if (ocfs2_is_empty_extent(&right_leaf_el->l_recs[0])) {
+		/*
+		 * It's legal for us to proceed if the right leaf is
+		 * the rightmost one and it has an empty extent. There
+		 * are two cases to handle - whether the leaf will be
+		 * empty after removal or not. If the leaf isn't empty
+		 * then just remove the empty extent up front. The
+		 * next block will handle empty leaves by flagging
+		 * them for unlink.
+		 *
+		 * Non rightmost leaves will throw -EAGAIN and the
+		 * caller can manually move the subtree and retry.
+		 */
+
+		if (eb->h_next_leaf_blk != 0ULL)
+			return -EAGAIN;
+
+		if (le16_to_cpu(right_leaf_el->l_next_free_rec) > 1) {
+			ret = ocfs2_journal_access_eb(handle, et->et_ci,
+						      path_leaf_bh(right_path),
+						      OCFS2_JOURNAL_ACCESS_WRITE);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+
+			ocfs2_remove_empty_extent(right_leaf_el);
+		} else
+			right_has_empty = 1;
+	}
+
+	if (eb->h_next_leaf_blk == 0ULL &&
+	    le16_to_cpu(right_leaf_el->l_next_free_rec) == 1) {
+		/*
+		 * We have to update i_last_eb_blk during the meta
+		 * data delete.
+		 */
+		ret = ocfs2_et_root_journal_access(handle, et,
+						   OCFS2_JOURNAL_ACCESS_WRITE);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		del_right_subtree = 1;
+	}
+
+	/*
+	 * Getting here with an empty extent in the right path implies
+	 * that it's the rightmost path and will be deleted.
+	 */
+	BUG_ON(right_has_empty && !del_right_subtree);
+
+	ret = ocfs2_path_bh_journal_access(handle, et->et_ci, right_path,
+					   subtree_index);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	for(i = subtree_index + 1; i < path_num_items(right_path); i++) {
+		ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
+						   right_path, i);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
+						   left_path, i);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+	if (!right_has_empty) {
+		/*
+		 * Only do this if we're moving a real
+		 * record. Otherwise, the action is delayed until
+		 * after removal of the right path in which case we
+		 * can do a simple shift to remove the empty extent.
+		 */
+		ocfs2_rotate_leaf(left_leaf_el, &right_leaf_el->l_recs[0]);
+		memset(&right_leaf_el->l_recs[0], 0,
+		       sizeof(struct ocfs2_extent_rec));
+	}
+	if (eb->h_next_leaf_blk == 0ULL) {
+		/*
+		 * Move recs over to get rid of empty extent, decrease
+		 * next_free. This is allowed to remove the last
+		 * extent in our leaf (setting l_next_free_rec to
+		 * zero) - the delete code below won't care.
+		 */
+		ocfs2_remove_empty_extent(right_leaf_el);
+	}
+
+	ocfs2_journal_dirty(handle, path_leaf_bh(left_path));
+	ocfs2_journal_dirty(handle, path_leaf_bh(right_path));
+
+	if (del_right_subtree) {
+		ocfs2_unlink_subtree(handle, et, left_path, right_path,
+				     subtree_index, dealloc);
+		ret = ocfs2_update_edge_lengths(handle, et, left_path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
+		ocfs2_et_set_last_eb_blk(et, le64_to_cpu(eb->h_blkno));
+
+		/*
+		 * Removal of the extent in the left leaf was skipped
+		 * above so we could delete the right path
+		 * 1st.
+		 */
+		if (right_has_empty)
+			ocfs2_remove_empty_extent(left_leaf_el);
+
+		ocfs2_journal_dirty(handle, et_root_bh);
+
+		*deleted = 1;
+	} else
+		ocfs2_complete_edge_insert(handle, left_path, right_path,
+					   subtree_index);
+
+out:
+	return ret;
+}
+
+/*
+ * Given a full path, determine what cpos value would return us a path
+ * containing the leaf immediately to the right of the current one.
+ *
+ * Will return zero if the path passed in is already the rightmost path.
+ *
+ * This looks similar, but is subtly different to
+ * ocfs2_find_cpos_for_left_leaf().
+ */
+int ocfs2_find_cpos_for_right_leaf(struct super_block *sb,
+				   struct ocfs2_path *path, u32 *cpos)
+{
+	int i, j, ret = 0;
+	u64 blkno;
+	struct ocfs2_extent_list *el;
+
+	*cpos = 0;
+
+	if (path->p_tree_depth == 0)
+		return 0;
+
+	blkno = path_leaf_bh(path)->b_blocknr;
+
+	/* Start at the tree node just above the leaf and work our way up. */
+	i = path->p_tree_depth - 1;
+	while (i >= 0) {
+		int next_free;
+
+		el = path->p_node[i].el;
+
+		/*
+		 * Find the extent record just after the one in our
+		 * path.
+		 */
+		next_free = le16_to_cpu(el->l_next_free_rec);
+		for(j = 0; j < le16_to_cpu(el->l_next_free_rec); j++) {
+			if (le64_to_cpu(el->l_recs[j].e_blkno) == blkno) {
+				if (j == (next_free - 1)) {
+					if (i == 0) {
+						/*
+						 * We've determined that the
+						 * path specified is already
+						 * the rightmost one - return a
+						 * cpos of zero.
+						 */
+						goto out;
+					}
+					/*
+					 * The rightmost record points to our
+					 * leaf - we need to travel up the
+					 * tree one level.
+					 */
+					goto next_node;
+				}
+
+				*cpos = le32_to_cpu(el->l_recs[j + 1].e_cpos);
+				goto out;
+			}
+		}
+
+		/*
+		 * If we got here, we never found a valid node where
+		 * the tree indicated one should be.
+		 */
+		ocfs2_error(sb, "Invalid extent tree at extent block %llu\n",
+			    (unsigned long long)blkno);
+		ret = -EROFS;
+		goto out;
+
+next_node:
+		blkno = path->p_node[i].bh->b_blocknr;
+		i--;
+	}
+
+out:
+	return ret;
+}
+
+static int ocfs2_rotate_rightmost_leaf_left(handle_t *handle,
+					    struct ocfs2_extent_tree *et,
+					    struct ocfs2_path *path)
+{
+	int ret;
+	struct buffer_head *bh = path_leaf_bh(path);
+	struct ocfs2_extent_list *el = path_leaf_el(path);
+
+	if (!ocfs2_is_empty_extent(&el->l_recs[0]))
+		return 0;
+
+	ret = ocfs2_path_bh_journal_access(handle, et->et_ci, path,
+					   path_num_items(path) - 1);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ocfs2_remove_empty_extent(el);
+	ocfs2_journal_dirty(handle, bh);
+
+out:
+	return ret;
+}
+
+static int __ocfs2_rotate_tree_left(handle_t *handle,
+				    struct ocfs2_extent_tree *et,
+				    int orig_credits,
+				    struct ocfs2_path *path,
+				    struct ocfs2_cached_dealloc_ctxt *dealloc,
+				    struct ocfs2_path **empty_extent_path)
+{
+	int ret, subtree_root, deleted;
+	u32 right_cpos;
+	struct ocfs2_path *left_path = NULL;
+	struct ocfs2_path *right_path = NULL;
+	struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
+
+	if (!ocfs2_is_empty_extent(&(path_leaf_el(path)->l_recs[0])))
+		return 0;
+
+	*empty_extent_path = NULL;
+
+	ret = ocfs2_find_cpos_for_right_leaf(sb, path, &right_cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	left_path = ocfs2_new_path_from_path(path);
+	if (!left_path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ocfs2_cp_path(left_path, path);
+
+	right_path = ocfs2_new_path_from_path(path);
+	if (!right_path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	while (right_cpos) {
+		ret = ocfs2_find_path(et->et_ci, right_path, right_cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		subtree_root = ocfs2_find_subtree_root(et, left_path,
+						       right_path);
+
+		trace_ocfs2_rotate_subtree(subtree_root,
+		     (unsigned long long)
+		     right_path->p_node[subtree_root].bh->b_blocknr,
+		     right_path->p_tree_depth);
+
+		ret = ocfs2_extend_rotate_transaction(handle, 0,
+						      orig_credits, left_path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/*
+		 * Caller might still want to make changes to the
+		 * tree root, so re-add it to the journal here.
+		 */
+		ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
+						   left_path, 0);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_rotate_subtree_left(handle, et, left_path,
+						right_path, subtree_root,
+						dealloc, &deleted);
+		if (ret == -EAGAIN) {
+			/*
+			 * The rotation has to temporarily stop due to
+			 * the right subtree having an empty
+			 * extent. Pass it back to the caller for a
+			 * fixup.
+			 */
+			*empty_extent_path = right_path;
+			right_path = NULL;
+			goto out;
+		}
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/*
+		 * The subtree rotate might have removed records on
+		 * the rightmost edge. If so, then rotation is
+		 * complete.
+		 */
+		if (deleted)
+			break;
+
+		ocfs2_mv_path(left_path, right_path);
+
+		ret = ocfs2_find_cpos_for_right_leaf(sb, left_path,
+						     &right_cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+out:
+	ocfs2_free_path(right_path);
+	ocfs2_free_path(left_path);
+
+	return ret;
+}
+
+static int ocfs2_remove_rightmost_path(handle_t *handle,
+				struct ocfs2_extent_tree *et,
+				struct ocfs2_path *path,
+				struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+	int ret, subtree_index;
+	u32 cpos;
+	struct ocfs2_path *left_path = NULL;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list *el;
+
+	ret = ocfs2_et_sanity_check(et);
+	if (ret)
+		goto out;
+
+	ret = ocfs2_journal_access_path(et->et_ci, handle, path);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_find_cpos_for_left_leaf(ocfs2_metadata_cache_get_super(et->et_ci),
+					    path, &cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (cpos) {
+		/*
+		 * We have a path to the left of this one - it needs
+		 * an update too.
+		 */
+		left_path = ocfs2_new_path_from_path(path);
+		if (!left_path) {
+			ret = -ENOMEM;
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_find_path(et->et_ci, left_path, cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_journal_access_path(et->et_ci, handle, left_path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		subtree_index = ocfs2_find_subtree_root(et, left_path, path);
+
+		ocfs2_unlink_subtree(handle, et, left_path, path,
+				     subtree_index, dealloc);
+		ret = ocfs2_update_edge_lengths(handle, et, left_path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
+		ocfs2_et_set_last_eb_blk(et, le64_to_cpu(eb->h_blkno));
+	} else {
+		/*
+		 * 'path' is also the leftmost path which
+		 * means it must be the only one. This gets
+		 * handled differently because we want to
+		 * revert the root back to having extents
+		 * in-line.
+		 */
+		ocfs2_unlink_path(handle, et, dealloc, path, 1);
+
+		el = et->et_root_el;
+		el->l_tree_depth = 0;
+		el->l_next_free_rec = 0;
+		memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
+
+		ocfs2_et_set_last_eb_blk(et, 0);
+	}
+
+	ocfs2_journal_dirty(handle, path_root_bh(path));
+
+out:
+	ocfs2_free_path(left_path);
+	return ret;
+}
+
+static int ocfs2_remove_rightmost_empty_extent(struct ocfs2_super *osb,
+				struct ocfs2_extent_tree *et,
+				struct ocfs2_path *path,
+				struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+	handle_t *handle;
+	int ret;
+	int credits = path->p_tree_depth * 2 + 1;
+
+	handle = ocfs2_start_trans(osb, credits);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		mlog_errno(ret);
+		return ret;
+	}
+
+	ret = ocfs2_remove_rightmost_path(handle, et, path, dealloc);
+	if (ret)
+		mlog_errno(ret);
+
+	ocfs2_commit_trans(osb, handle);
+	return ret;
+}
+
+/*
+ * Left rotation of btree records.
+ *
+ * In many ways, this is (unsurprisingly) the opposite of right
+ * rotation. We start at some non-rightmost path containing an empty
+ * extent in the leaf block. The code works its way to the rightmost
+ * path by rotating records to the left in every subtree.
+ *
+ * This is used by any code which reduces the number of extent records
+ * in a leaf. After removal, an empty record should be placed in the
+ * leftmost list position.
+ *
+ * This won't handle a length update of the rightmost path records if
+ * the rightmost tree leaf record is removed so the caller is
+ * responsible for detecting and correcting that.
+ */
+static int ocfs2_rotate_tree_left(handle_t *handle,
+				  struct ocfs2_extent_tree *et,
+				  struct ocfs2_path *path,
+				  struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+	int ret, orig_credits = jbd2_handle_buffer_credits(handle);
+	struct ocfs2_path *tmp_path = NULL, *restart_path = NULL;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list *el;
+
+	el = path_leaf_el(path);
+	if (!ocfs2_is_empty_extent(&el->l_recs[0]))
+		return 0;
+
+	if (path->p_tree_depth == 0) {
+rightmost_no_delete:
+		/*
+		 * Inline extents. This is trivially handled, so do
+		 * it up front.
+		 */
+		ret = ocfs2_rotate_rightmost_leaf_left(handle, et, path);
+		if (ret)
+			mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * Handle rightmost branch now. There's several cases:
+	 *  1) simple rotation leaving records in there. That's trivial.
+	 *  2) rotation requiring a branch delete - there's no more
+	 *     records left. Two cases of this:
+	 *     a) There are branches to the left.
+	 *     b) This is also the leftmost (the only) branch.
+	 *
+	 *  1) is handled via ocfs2_rotate_rightmost_leaf_left()
+	 *  2a) we need the left branch so that we can update it with the unlink
+	 *  2b) we need to bring the root back to inline extents.
+	 */
+
+	eb = (struct ocfs2_extent_block *)path_leaf_bh(path)->b_data;
+	el = &eb->h_list;
+	if (eb->h_next_leaf_blk == 0) {
+		/*
+		 * This gets a bit tricky if we're going to delete the
+		 * rightmost path. Get the other cases out of the way
+		 * 1st.
+		 */
+		if (le16_to_cpu(el->l_next_free_rec) > 1)
+			goto rightmost_no_delete;
+
+		if (le16_to_cpu(el->l_next_free_rec) == 0) {
+			ret = ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+					"Owner %llu has empty extent block at %llu\n",
+					(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+					(unsigned long long)le64_to_cpu(eb->h_blkno));
+			goto out;
+		}
+
+		/*
+		 * XXX: The caller can not trust "path" any more after
+		 * this as it will have been deleted. What do we do?
+		 *
+		 * In theory the rotate-for-merge code will never get
+		 * here because it'll always ask for a rotate in a
+		 * nonempty list.
+		 */
+
+		ret = ocfs2_remove_rightmost_path(handle, et, path,
+						  dealloc);
+		if (ret)
+			mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * Now we can loop, remembering the path we get from -EAGAIN
+	 * and restarting from there.
+	 */
+try_rotate:
+	ret = __ocfs2_rotate_tree_left(handle, et, orig_credits, path,
+				       dealloc, &restart_path);
+	if (ret && ret != -EAGAIN) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	while (ret == -EAGAIN) {
+		tmp_path = restart_path;
+		restart_path = NULL;
+
+		ret = __ocfs2_rotate_tree_left(handle, et, orig_credits,
+					       tmp_path, dealloc,
+					       &restart_path);
+		if (ret && ret != -EAGAIN) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ocfs2_free_path(tmp_path);
+		tmp_path = NULL;
+
+		if (ret == 0)
+			goto try_rotate;
+	}
+
+out:
+	ocfs2_free_path(tmp_path);
+	ocfs2_free_path(restart_path);
+	return ret;
+}
+
+static void ocfs2_cleanup_merge(struct ocfs2_extent_list *el,
+				int index)
+{
+	struct ocfs2_extent_rec *rec = &el->l_recs[index];
+	unsigned int size;
+
+	if (rec->e_leaf_clusters == 0) {
+		/*
+		 * We consumed all of the merged-from record. An empty
+		 * extent cannot exist anywhere but the 1st array
+		 * position, so move things over if the merged-from
+		 * record doesn't occupy that position.
+		 *
+		 * This creates a new empty extent so the caller
+		 * should be smart enough to have removed any existing
+		 * ones.
+		 */
+		if (index > 0) {
+			BUG_ON(ocfs2_is_empty_extent(&el->l_recs[0]));
+			size = index * sizeof(struct ocfs2_extent_rec);
+			memmove(&el->l_recs[1], &el->l_recs[0], size);
+		}
+
+		/*
+		 * Always memset - the caller doesn't check whether it
+		 * created an empty extent, so there could be junk in
+		 * the other fields.
+		 */
+		memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
+	}
+}
+
+static int ocfs2_get_right_path(struct ocfs2_extent_tree *et,
+				struct ocfs2_path *left_path,
+				struct ocfs2_path **ret_right_path)
+{
+	int ret;
+	u32 right_cpos;
+	struct ocfs2_path *right_path = NULL;
+	struct ocfs2_extent_list *left_el;
+
+	*ret_right_path = NULL;
+
+	/* This function shouldn't be called for non-trees. */
+	BUG_ON(left_path->p_tree_depth == 0);
+
+	left_el = path_leaf_el(left_path);
+	BUG_ON(left_el->l_next_free_rec != left_el->l_count);
+
+	ret = ocfs2_find_cpos_for_right_leaf(ocfs2_metadata_cache_get_super(et->et_ci),
+					     left_path, &right_cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/* This function shouldn't be called for the rightmost leaf. */
+	BUG_ON(right_cpos == 0);
+
+	right_path = ocfs2_new_path_from_path(left_path);
+	if (!right_path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_find_path(et->et_ci, right_path, right_cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	*ret_right_path = right_path;
+out:
+	if (ret)
+		ocfs2_free_path(right_path);
+	return ret;
+}
+
+/*
+ * Remove split_rec clusters from the record at index and merge them
+ * onto the beginning of the record "next" to it.
+ * For index < l_count - 1, the next means the extent rec at index + 1.
+ * For index == l_count - 1, the "next" means the 1st extent rec of the
+ * next extent block.
+ */
+static int ocfs2_merge_rec_right(struct ocfs2_path *left_path,
+				 handle_t *handle,
+				 struct ocfs2_extent_tree *et,
+				 struct ocfs2_extent_rec *split_rec,
+				 int index)
+{
+	int ret, next_free, i;
+	unsigned int split_clusters = le16_to_cpu(split_rec->e_leaf_clusters);
+	struct ocfs2_extent_rec *left_rec;
+	struct ocfs2_extent_rec *right_rec;
+	struct ocfs2_extent_list *right_el;
+	struct ocfs2_path *right_path = NULL;
+	int subtree_index = 0;
+	struct ocfs2_extent_list *el = path_leaf_el(left_path);
+	struct buffer_head *bh = path_leaf_bh(left_path);
+	struct buffer_head *root_bh = NULL;
+
+	BUG_ON(index >= le16_to_cpu(el->l_next_free_rec));
+	left_rec = &el->l_recs[index];
+
+	if (index == le16_to_cpu(el->l_next_free_rec) - 1 &&
+	    le16_to_cpu(el->l_next_free_rec) == le16_to_cpu(el->l_count)) {
+		/* we meet with a cross extent block merge. */
+		ret = ocfs2_get_right_path(et, left_path, &right_path);
+		if (ret) {
+			mlog_errno(ret);
+			return ret;
+		}
+
+		right_el = path_leaf_el(right_path);
+		next_free = le16_to_cpu(right_el->l_next_free_rec);
+		BUG_ON(next_free <= 0);
+		right_rec = &right_el->l_recs[0];
+		if (ocfs2_is_empty_extent(right_rec)) {
+			BUG_ON(next_free <= 1);
+			right_rec = &right_el->l_recs[1];
+		}
+
+		BUG_ON(le32_to_cpu(left_rec->e_cpos) +
+		       le16_to_cpu(left_rec->e_leaf_clusters) !=
+		       le32_to_cpu(right_rec->e_cpos));
+
+		subtree_index = ocfs2_find_subtree_root(et, left_path,
+							right_path);
+
+		ret = ocfs2_extend_rotate_transaction(handle, subtree_index,
+					jbd2_handle_buffer_credits(handle),
+					right_path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		root_bh = left_path->p_node[subtree_index].bh;
+		BUG_ON(root_bh != right_path->p_node[subtree_index].bh);
+
+		ret = ocfs2_path_bh_journal_access(handle, et->et_ci, right_path,
+						   subtree_index);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		for (i = subtree_index + 1;
+		     i < path_num_items(right_path); i++) {
+			ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
+							   right_path, i);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+
+			ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
+							   left_path, i);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+		}
+
+	} else {
+		BUG_ON(index == le16_to_cpu(el->l_next_free_rec) - 1);
+		right_rec = &el->l_recs[index + 1];
+	}
+
+	ret = ocfs2_path_bh_journal_access(handle, et->et_ci, left_path,
+					   path_num_items(left_path) - 1);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	le16_add_cpu(&left_rec->e_leaf_clusters, -split_clusters);
+
+	le32_add_cpu(&right_rec->e_cpos, -split_clusters);
+	le64_add_cpu(&right_rec->e_blkno,
+		     -ocfs2_clusters_to_blocks(ocfs2_metadata_cache_get_super(et->et_ci),
+					       split_clusters));
+	le16_add_cpu(&right_rec->e_leaf_clusters, split_clusters);
+
+	ocfs2_cleanup_merge(el, index);
+
+	ocfs2_journal_dirty(handle, bh);
+	if (right_path) {
+		ocfs2_journal_dirty(handle, path_leaf_bh(right_path));
+		ocfs2_complete_edge_insert(handle, left_path, right_path,
+					   subtree_index);
+	}
+out:
+	ocfs2_free_path(right_path);
+	return ret;
+}
+
+static int ocfs2_get_left_path(struct ocfs2_extent_tree *et,
+			       struct ocfs2_path *right_path,
+			       struct ocfs2_path **ret_left_path)
+{
+	int ret;
+	u32 left_cpos;
+	struct ocfs2_path *left_path = NULL;
+
+	*ret_left_path = NULL;
+
+	/* This function shouldn't be called for non-trees. */
+	BUG_ON(right_path->p_tree_depth == 0);
+
+	ret = ocfs2_find_cpos_for_left_leaf(ocfs2_metadata_cache_get_super(et->et_ci),
+					    right_path, &left_cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/* This function shouldn't be called for the leftmost leaf. */
+	BUG_ON(left_cpos == 0);
+
+	left_path = ocfs2_new_path_from_path(right_path);
+	if (!left_path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_find_path(et->et_ci, left_path, left_cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	*ret_left_path = left_path;
+out:
+	if (ret)
+		ocfs2_free_path(left_path);
+	return ret;
+}
+
+/*
+ * Remove split_rec clusters from the record at index and merge them
+ * onto the tail of the record "before" it.
+ * For index > 0, the "before" means the extent rec at index - 1.
+ *
+ * For index == 0, the "before" means the last record of the previous
+ * extent block. And there is also a situation that we may need to
+ * remove the rightmost leaf extent block in the right_path and change
+ * the right path to indicate the new rightmost path.
+ */
+static int ocfs2_merge_rec_left(struct ocfs2_path *right_path,
+				handle_t *handle,
+				struct ocfs2_extent_tree *et,
+				struct ocfs2_extent_rec *split_rec,
+				struct ocfs2_cached_dealloc_ctxt *dealloc,
+				int index)
+{
+	int ret, i, subtree_index = 0, has_empty_extent = 0;
+	unsigned int split_clusters = le16_to_cpu(split_rec->e_leaf_clusters);
+	struct ocfs2_extent_rec *left_rec;
+	struct ocfs2_extent_rec *right_rec;
+	struct ocfs2_extent_list *el = path_leaf_el(right_path);
+	struct buffer_head *bh = path_leaf_bh(right_path);
+	struct buffer_head *root_bh = NULL;
+	struct ocfs2_path *left_path = NULL;
+	struct ocfs2_extent_list *left_el;
+
+	BUG_ON(index < 0);
+
+	right_rec = &el->l_recs[index];
+	if (index == 0) {
+		/* we meet with a cross extent block merge. */
+		ret = ocfs2_get_left_path(et, right_path, &left_path);
+		if (ret) {
+			mlog_errno(ret);
+			return ret;
+		}
+
+		left_el = path_leaf_el(left_path);
+		BUG_ON(le16_to_cpu(left_el->l_next_free_rec) !=
+		       le16_to_cpu(left_el->l_count));
+
+		left_rec = &left_el->l_recs[
+				le16_to_cpu(left_el->l_next_free_rec) - 1];
+		BUG_ON(le32_to_cpu(left_rec->e_cpos) +
+		       le16_to_cpu(left_rec->e_leaf_clusters) !=
+		       le32_to_cpu(split_rec->e_cpos));
+
+		subtree_index = ocfs2_find_subtree_root(et, left_path,
+							right_path);
+
+		ret = ocfs2_extend_rotate_transaction(handle, subtree_index,
+					jbd2_handle_buffer_credits(handle),
+					left_path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		root_bh = left_path->p_node[subtree_index].bh;
+		BUG_ON(root_bh != right_path->p_node[subtree_index].bh);
+
+		ret = ocfs2_path_bh_journal_access(handle, et->et_ci, right_path,
+						   subtree_index);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		for (i = subtree_index + 1;
+		     i < path_num_items(right_path); i++) {
+			ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
+							   right_path, i);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+
+			ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
+							   left_path, i);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+		}
+	} else {
+		left_rec = &el->l_recs[index - 1];
+		if (ocfs2_is_empty_extent(&el->l_recs[0]))
+			has_empty_extent = 1;
+	}
+
+	ret = ocfs2_path_bh_journal_access(handle, et->et_ci, right_path,
+					   path_num_items(right_path) - 1);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (has_empty_extent && index == 1) {
+		/*
+		 * The easy case - we can just plop the record right in.
+		 */
+		*left_rec = *split_rec;
+	} else
+		le16_add_cpu(&left_rec->e_leaf_clusters, split_clusters);
+
+	le32_add_cpu(&right_rec->e_cpos, split_clusters);
+	le64_add_cpu(&right_rec->e_blkno,
+		     ocfs2_clusters_to_blocks(ocfs2_metadata_cache_get_super(et->et_ci),
+					      split_clusters));
+	le16_add_cpu(&right_rec->e_leaf_clusters, -split_clusters);
+
+	ocfs2_cleanup_merge(el, index);
+
+	ocfs2_journal_dirty(handle, bh);
+	if (left_path) {
+		ocfs2_journal_dirty(handle, path_leaf_bh(left_path));
+
+		/*
+		 * In the situation that the right_rec is empty and the extent
+		 * block is empty also,  ocfs2_complete_edge_insert can't handle
+		 * it and we need to delete the right extent block.
+		 */
+		if (le16_to_cpu(right_rec->e_leaf_clusters) == 0 &&
+		    le16_to_cpu(el->l_next_free_rec) == 1) {
+			/* extend credit for ocfs2_remove_rightmost_path */
+			ret = ocfs2_extend_rotate_transaction(handle, 0,
+					jbd2_handle_buffer_credits(handle),
+					right_path);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+
+			ret = ocfs2_remove_rightmost_path(handle, et,
+							  right_path,
+							  dealloc);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+
+			/* Now the rightmost extent block has been deleted.
+			 * So we use the new rightmost path.
+			 */
+			ocfs2_mv_path(right_path, left_path);
+			left_path = NULL;
+		} else
+			ocfs2_complete_edge_insert(handle, left_path,
+						   right_path, subtree_index);
+	}
+out:
+	ocfs2_free_path(left_path);
+	return ret;
+}
+
+static int ocfs2_try_to_merge_extent(handle_t *handle,
+				     struct ocfs2_extent_tree *et,
+				     struct ocfs2_path *path,
+				     int split_index,
+				     struct ocfs2_extent_rec *split_rec,
+				     struct ocfs2_cached_dealloc_ctxt *dealloc,
+				     struct ocfs2_merge_ctxt *ctxt)
+{
+	int ret = 0;
+	struct ocfs2_extent_list *el = path_leaf_el(path);
+	struct ocfs2_extent_rec *rec = &el->l_recs[split_index];
+
+	BUG_ON(ctxt->c_contig_type == CONTIG_NONE);
+
+	if (ctxt->c_split_covers_rec && ctxt->c_has_empty_extent) {
+		/* extend credit for ocfs2_remove_rightmost_path */
+		ret = ocfs2_extend_rotate_transaction(handle, 0,
+				jbd2_handle_buffer_credits(handle),
+				path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+		/*
+		 * The merge code will need to create an empty
+		 * extent to take the place of the newly
+		 * emptied slot. Remove any pre-existing empty
+		 * extents - having more than one in a leaf is
+		 * illegal.
+		 */
+		ret = ocfs2_rotate_tree_left(handle, et, path, dealloc);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+		split_index--;
+		rec = &el->l_recs[split_index];
+	}
+
+	if (ctxt->c_contig_type == CONTIG_LEFTRIGHT) {
+		/*
+		 * Left-right contig implies this.
+		 */
+		BUG_ON(!ctxt->c_split_covers_rec);
+
+		/*
+		 * Since the leftright insert always covers the entire
+		 * extent, this call will delete the insert record
+		 * entirely, resulting in an empty extent record added to
+		 * the extent block.
+		 *
+		 * Since the adding of an empty extent shifts
+		 * everything back to the right, there's no need to
+		 * update split_index here.
+		 *
+		 * When the split_index is zero, we need to merge it to the
+		 * prevoius extent block. It is more efficient and easier
+		 * if we do merge_right first and merge_left later.
+		 */
+		ret = ocfs2_merge_rec_right(path, handle, et, split_rec,
+					    split_index);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/*
+		 * We can only get this from logic error above.
+		 */
+		BUG_ON(!ocfs2_is_empty_extent(&el->l_recs[0]));
+
+		/* extend credit for ocfs2_remove_rightmost_path */
+		ret = ocfs2_extend_rotate_transaction(handle, 0,
+					jbd2_handle_buffer_credits(handle),
+					path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/* The merge left us with an empty extent, remove it. */
+		ret = ocfs2_rotate_tree_left(handle, et, path, dealloc);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		rec = &el->l_recs[split_index];
+
+		/*
+		 * Note that we don't pass split_rec here on purpose -
+		 * we've merged it into the rec already.
+		 */
+		ret = ocfs2_merge_rec_left(path, handle, et, rec,
+					   dealloc, split_index);
+
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/* extend credit for ocfs2_remove_rightmost_path */
+		ret = ocfs2_extend_rotate_transaction(handle, 0,
+				jbd2_handle_buffer_credits(handle),
+				path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_rotate_tree_left(handle, et, path, dealloc);
+		/*
+		 * Error from this last rotate is not critical, so
+		 * print but don't bubble it up.
+		 */
+		if (ret)
+			mlog_errno(ret);
+		ret = 0;
+	} else {
+		/*
+		 * Merge a record to the left or right.
+		 *
+		 * 'contig_type' is relative to the existing record,
+		 * so for example, if we're "right contig", it's to
+		 * the record on the left (hence the left merge).
+		 */
+		if (ctxt->c_contig_type == CONTIG_RIGHT) {
+			ret = ocfs2_merge_rec_left(path, handle, et,
+						   split_rec, dealloc,
+						   split_index);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+		} else {
+			ret = ocfs2_merge_rec_right(path, handle,
+						    et, split_rec,
+						    split_index);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+		}
+
+		if (ctxt->c_split_covers_rec) {
+			/* extend credit for ocfs2_remove_rightmost_path */
+			ret = ocfs2_extend_rotate_transaction(handle, 0,
+					jbd2_handle_buffer_credits(handle),
+					path);
+			if (ret) {
+				mlog_errno(ret);
+				ret = 0;
+				goto out;
+			}
+
+			/*
+			 * The merge may have left an empty extent in
+			 * our leaf. Try to rotate it away.
+			 */
+			ret = ocfs2_rotate_tree_left(handle, et, path,
+						     dealloc);
+			if (ret)
+				mlog_errno(ret);
+			ret = 0;
+		}
+	}
+
+out:
+	return ret;
+}
+
+static void ocfs2_subtract_from_rec(struct super_block *sb,
+				    enum ocfs2_split_type split,
+				    struct ocfs2_extent_rec *rec,
+				    struct ocfs2_extent_rec *split_rec)
+{
+	u64 len_blocks;
+
+	len_blocks = ocfs2_clusters_to_blocks(sb,
+				le16_to_cpu(split_rec->e_leaf_clusters));
+
+	if (split == SPLIT_LEFT) {
+		/*
+		 * Region is on the left edge of the existing
+		 * record.
+		 */
+		le32_add_cpu(&rec->e_cpos,
+			     le16_to_cpu(split_rec->e_leaf_clusters));
+		le64_add_cpu(&rec->e_blkno, len_blocks);
+		le16_add_cpu(&rec->e_leaf_clusters,
+			     -le16_to_cpu(split_rec->e_leaf_clusters));
+	} else {
+		/*
+		 * Region is on the right edge of the existing
+		 * record.
+		 */
+		le16_add_cpu(&rec->e_leaf_clusters,
+			     -le16_to_cpu(split_rec->e_leaf_clusters));
+	}
+}
+
+/*
+ * Do the final bits of extent record insertion at the target leaf
+ * list. If this leaf is part of an allocation tree, it is assumed
+ * that the tree above has been prepared.
+ */
+static void ocfs2_insert_at_leaf(struct ocfs2_extent_tree *et,
+				 struct ocfs2_extent_rec *insert_rec,
+				 struct ocfs2_extent_list *el,
+				 struct ocfs2_insert_type *insert)
+{
+	int i = insert->ins_contig_index;
+	unsigned int range;
+	struct ocfs2_extent_rec *rec;
+
+	BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
+
+	if (insert->ins_split != SPLIT_NONE) {
+		i = ocfs2_search_extent_list(el, le32_to_cpu(insert_rec->e_cpos));
+		BUG_ON(i == -1);
+		rec = &el->l_recs[i];
+		ocfs2_subtract_from_rec(ocfs2_metadata_cache_get_super(et->et_ci),
+					insert->ins_split, rec,
+					insert_rec);
+		goto rotate;
+	}
+
+	/*
+	 * Contiguous insert - either left or right.
+	 */
+	if (insert->ins_contig != CONTIG_NONE) {
+		rec = &el->l_recs[i];
+		if (insert->ins_contig == CONTIG_LEFT) {
+			rec->e_blkno = insert_rec->e_blkno;
+			rec->e_cpos = insert_rec->e_cpos;
+		}
+		le16_add_cpu(&rec->e_leaf_clusters,
+			     le16_to_cpu(insert_rec->e_leaf_clusters));
+		return;
+	}
+
+	/*
+	 * Handle insert into an empty leaf.
+	 */
+	if (le16_to_cpu(el->l_next_free_rec) == 0 ||
+	    ((le16_to_cpu(el->l_next_free_rec) == 1) &&
+	     ocfs2_is_empty_extent(&el->l_recs[0]))) {
+		el->l_recs[0] = *insert_rec;
+		el->l_next_free_rec = cpu_to_le16(1);
+		return;
+	}
+
+	/*
+	 * Appending insert.
+	 */
+	if (insert->ins_appending == APPEND_TAIL) {
+		i = le16_to_cpu(el->l_next_free_rec) - 1;
+		rec = &el->l_recs[i];
+		range = le32_to_cpu(rec->e_cpos)
+			+ le16_to_cpu(rec->e_leaf_clusters);
+		BUG_ON(le32_to_cpu(insert_rec->e_cpos) < range);
+
+		mlog_bug_on_msg(le16_to_cpu(el->l_next_free_rec) >=
+				le16_to_cpu(el->l_count),
+				"owner %llu, depth %u, count %u, next free %u, "
+				"rec.cpos %u, rec.clusters %u, "
+				"insert.cpos %u, insert.clusters %u\n",
+				ocfs2_metadata_cache_owner(et->et_ci),
+				le16_to_cpu(el->l_tree_depth),
+				le16_to_cpu(el->l_count),
+				le16_to_cpu(el->l_next_free_rec),
+				le32_to_cpu(el->l_recs[i].e_cpos),
+				le16_to_cpu(el->l_recs[i].e_leaf_clusters),
+				le32_to_cpu(insert_rec->e_cpos),
+				le16_to_cpu(insert_rec->e_leaf_clusters));
+		i++;
+		el->l_recs[i] = *insert_rec;
+		le16_add_cpu(&el->l_next_free_rec, 1);
+		return;
+	}
+
+rotate:
+	/*
+	 * Ok, we have to rotate.
+	 *
+	 * At this point, it is safe to assume that inserting into an
+	 * empty leaf and appending to a leaf have both been handled
+	 * above.
+	 *
+	 * This leaf needs to have space, either by the empty 1st
+	 * extent record, or by virtue of an l_next_free_rec < l_count.
+	 */
+	ocfs2_rotate_leaf(el, insert_rec);
+}
+
+static void ocfs2_adjust_rightmost_records(handle_t *handle,
+					   struct ocfs2_extent_tree *et,
+					   struct ocfs2_path *path,
+					   struct ocfs2_extent_rec *insert_rec)
+{
+	int i, next_free;
+	struct buffer_head *bh;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_extent_rec *rec;
+
+	/*
+	 * Update everything except the leaf block.
+	 */
+	for (i = 0; i < path->p_tree_depth; i++) {
+		bh = path->p_node[i].bh;
+		el = path->p_node[i].el;
+
+		next_free = le16_to_cpu(el->l_next_free_rec);
+		if (next_free == 0) {
+			ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+				    "Owner %llu has a bad extent list\n",
+				    (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci));
+			return;
+		}
+
+		rec = &el->l_recs[next_free - 1];
+
+		rec->e_int_clusters = insert_rec->e_cpos;
+		le32_add_cpu(&rec->e_int_clusters,
+			     le16_to_cpu(insert_rec->e_leaf_clusters));
+		le32_add_cpu(&rec->e_int_clusters,
+			     -le32_to_cpu(rec->e_cpos));
+
+		ocfs2_journal_dirty(handle, bh);
+	}
+}
+
+static int ocfs2_append_rec_to_path(handle_t *handle,
+				    struct ocfs2_extent_tree *et,
+				    struct ocfs2_extent_rec *insert_rec,
+				    struct ocfs2_path *right_path,
+				    struct ocfs2_path **ret_left_path)
+{
+	int ret, next_free;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_path *left_path = NULL;
+
+	*ret_left_path = NULL;
+
+	/*
+	 * This shouldn't happen for non-trees. The extent rec cluster
+	 * count manipulation below only works for interior nodes.
+	 */
+	BUG_ON(right_path->p_tree_depth == 0);
+
+	/*
+	 * If our appending insert is at the leftmost edge of a leaf,
+	 * then we might need to update the rightmost records of the
+	 * neighboring path.
+	 */
+	el = path_leaf_el(right_path);
+	next_free = le16_to_cpu(el->l_next_free_rec);
+	if (next_free == 0 ||
+	    (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0]))) {
+		u32 left_cpos;
+
+		ret = ocfs2_find_cpos_for_left_leaf(ocfs2_metadata_cache_get_super(et->et_ci),
+						    right_path, &left_cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		trace_ocfs2_append_rec_to_path(
+			(unsigned long long)
+			ocfs2_metadata_cache_owner(et->et_ci),
+			le32_to_cpu(insert_rec->e_cpos),
+			left_cpos);
+
+		/*
+		 * No need to worry if the append is already in the
+		 * leftmost leaf.
+		 */
+		if (left_cpos) {
+			left_path = ocfs2_new_path_from_path(right_path);
+			if (!left_path) {
+				ret = -ENOMEM;
+				mlog_errno(ret);
+				goto out;
+			}
+
+			ret = ocfs2_find_path(et->et_ci, left_path,
+					      left_cpos);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+
+			/*
+			 * ocfs2_insert_path() will pass the left_path to the
+			 * journal for us.
+			 */
+		}
+	}
+
+	ret = ocfs2_journal_access_path(et->et_ci, handle, right_path);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ocfs2_adjust_rightmost_records(handle, et, right_path, insert_rec);
+
+	*ret_left_path = left_path;
+	ret = 0;
+out:
+	if (ret != 0)
+		ocfs2_free_path(left_path);
+
+	return ret;
+}
+
+static void ocfs2_split_record(struct ocfs2_extent_tree *et,
+			       struct ocfs2_path *left_path,
+			       struct ocfs2_path *right_path,
+			       struct ocfs2_extent_rec *split_rec,
+			       enum ocfs2_split_type split)
+{
+	int index;
+	u32 cpos = le32_to_cpu(split_rec->e_cpos);
+	struct ocfs2_extent_list *left_el = NULL, *right_el, *insert_el, *el;
+	struct ocfs2_extent_rec *rec, *tmprec;
+
+	right_el = path_leaf_el(right_path);
+	if (left_path)
+		left_el = path_leaf_el(left_path);
+
+	el = right_el;
+	insert_el = right_el;
+	index = ocfs2_search_extent_list(el, cpos);
+	if (index != -1) {
+		if (index == 0 && left_path) {
+			BUG_ON(ocfs2_is_empty_extent(&el->l_recs[0]));
+
+			/*
+			 * This typically means that the record
+			 * started in the left path but moved to the
+			 * right as a result of rotation. We either
+			 * move the existing record to the left, or we
+			 * do the later insert there.
+			 *
+			 * In this case, the left path should always
+			 * exist as the rotate code will have passed
+			 * it back for a post-insert update.
+			 */
+
+			if (split == SPLIT_LEFT) {
+				/*
+				 * It's a left split. Since we know
+				 * that the rotate code gave us an
+				 * empty extent in the left path, we
+				 * can just do the insert there.
+				 */
+				insert_el = left_el;
+			} else {
+				/*
+				 * Right split - we have to move the
+				 * existing record over to the left
+				 * leaf. The insert will be into the
+				 * newly created empty extent in the
+				 * right leaf.
+				 */
+				tmprec = &right_el->l_recs[index];
+				ocfs2_rotate_leaf(left_el, tmprec);
+				el = left_el;
+
+				memset(tmprec, 0, sizeof(*tmprec));
+				index = ocfs2_search_extent_list(left_el, cpos);
+				BUG_ON(index == -1);
+			}
+		}
+	} else {
+		BUG_ON(!left_path);
+		BUG_ON(!ocfs2_is_empty_extent(&left_el->l_recs[0]));
+		/*
+		 * Left path is easy - we can just allow the insert to
+		 * happen.
+		 */
+		el = left_el;
+		insert_el = left_el;
+		index = ocfs2_search_extent_list(el, cpos);
+		BUG_ON(index == -1);
+	}
+
+	rec = &el->l_recs[index];
+	ocfs2_subtract_from_rec(ocfs2_metadata_cache_get_super(et->et_ci),
+				split, rec, split_rec);
+	ocfs2_rotate_leaf(insert_el, split_rec);
+}
+
+/*
+ * This function only does inserts on an allocation b-tree. For tree
+ * depth = 0, ocfs2_insert_at_leaf() is called directly.
+ *
+ * right_path is the path we want to do the actual insert
+ * in. left_path should only be passed in if we need to update that
+ * portion of the tree after an edge insert.
+ */
+static int ocfs2_insert_path(handle_t *handle,
+			     struct ocfs2_extent_tree *et,
+			     struct ocfs2_path *left_path,
+			     struct ocfs2_path *right_path,
+			     struct ocfs2_extent_rec *insert_rec,
+			     struct ocfs2_insert_type *insert)
+{
+	int ret, subtree_index;
+	struct buffer_head *leaf_bh = path_leaf_bh(right_path);
+
+	if (left_path) {
+		/*
+		 * There's a chance that left_path got passed back to
+		 * us without being accounted for in the
+		 * journal. Extend our transaction here to be sure we
+		 * can change those blocks.
+		 */
+		ret = ocfs2_extend_trans(handle, left_path->p_tree_depth);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_journal_access_path(et->et_ci, handle, left_path);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+	/*
+	 * Pass both paths to the journal. The majority of inserts
+	 * will be touching all components anyway.
+	 */
+	ret = ocfs2_journal_access_path(et->et_ci, handle, right_path);
+	if (ret < 0) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (insert->ins_split != SPLIT_NONE) {
+		/*
+		 * We could call ocfs2_insert_at_leaf() for some types
+		 * of splits, but it's easier to just let one separate
+		 * function sort it all out.
+		 */
+		ocfs2_split_record(et, left_path, right_path,
+				   insert_rec, insert->ins_split);
+
+		/*
+		 * Split might have modified either leaf and we don't
+		 * have a guarantee that the later edge insert will
+		 * dirty this for us.
+		 */
+		if (left_path)
+			ocfs2_journal_dirty(handle,
+					    path_leaf_bh(left_path));
+	} else
+		ocfs2_insert_at_leaf(et, insert_rec, path_leaf_el(right_path),
+				     insert);
+
+	ocfs2_journal_dirty(handle, leaf_bh);
+
+	if (left_path) {
+		/*
+		 * The rotate code has indicated that we need to fix
+		 * up portions of the tree after the insert.
+		 *
+		 * XXX: Should we extend the transaction here?
+		 */
+		subtree_index = ocfs2_find_subtree_root(et, left_path,
+							right_path);
+		ocfs2_complete_edge_insert(handle, left_path, right_path,
+					   subtree_index);
+	}
+
+	ret = 0;
+out:
+	return ret;
+}
+
+static int ocfs2_do_insert_extent(handle_t *handle,
+				  struct ocfs2_extent_tree *et,
+				  struct ocfs2_extent_rec *insert_rec,
+				  struct ocfs2_insert_type *type)
+{
+	int ret, rotate = 0;
+	u32 cpos;
+	struct ocfs2_path *right_path = NULL;
+	struct ocfs2_path *left_path = NULL;
+	struct ocfs2_extent_list *el;
+
+	el = et->et_root_el;
+
+	ret = ocfs2_et_root_journal_access(handle, et,
+					   OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (le16_to_cpu(el->l_tree_depth) == 0) {
+		ocfs2_insert_at_leaf(et, insert_rec, el, type);
+		goto out_update_clusters;
+	}
+
+	right_path = ocfs2_new_path_from_et(et);
+	if (!right_path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * Determine the path to start with. Rotations need the
+	 * rightmost path, everything else can go directly to the
+	 * target leaf.
+	 */
+	cpos = le32_to_cpu(insert_rec->e_cpos);
+	if (type->ins_appending == APPEND_NONE &&
+	    type->ins_contig == CONTIG_NONE) {
+		rotate = 1;
+		cpos = UINT_MAX;
+	}
+
+	ret = ocfs2_find_path(et->et_ci, right_path, cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * Rotations and appends need special treatment - they modify
+	 * parts of the tree's above them.
+	 *
+	 * Both might pass back a path immediate to the left of the
+	 * one being inserted to. This will be cause
+	 * ocfs2_insert_path() to modify the rightmost records of
+	 * left_path to account for an edge insert.
+	 *
+	 * XXX: When modifying this code, keep in mind that an insert
+	 * can wind up skipping both of these two special cases...
+	 */
+	if (rotate) {
+		ret = ocfs2_rotate_tree_right(handle, et, type->ins_split,
+					      le32_to_cpu(insert_rec->e_cpos),
+					      right_path, &left_path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/*
+		 * ocfs2_rotate_tree_right() might have extended the
+		 * transaction without re-journaling our tree root.
+		 */
+		ret = ocfs2_et_root_journal_access(handle, et,
+						   OCFS2_JOURNAL_ACCESS_WRITE);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	} else if (type->ins_appending == APPEND_TAIL
+		   && type->ins_contig != CONTIG_LEFT) {
+		ret = ocfs2_append_rec_to_path(handle, et, insert_rec,
+					       right_path, &left_path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+	ret = ocfs2_insert_path(handle, et, left_path, right_path,
+				insert_rec, type);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+out_update_clusters:
+	if (type->ins_split == SPLIT_NONE)
+		ocfs2_et_update_clusters(et,
+					 le16_to_cpu(insert_rec->e_leaf_clusters));
+
+	ocfs2_journal_dirty(handle, et->et_root_bh);
+
+out:
+	ocfs2_free_path(left_path);
+	ocfs2_free_path(right_path);
+
+	return ret;
+}
+
+static int ocfs2_figure_merge_contig_type(struct ocfs2_extent_tree *et,
+			       struct ocfs2_path *path,
+			       struct ocfs2_extent_list *el, int index,
+			       struct ocfs2_extent_rec *split_rec,
+			       struct ocfs2_merge_ctxt *ctxt)
+{
+	int status = 0;
+	enum ocfs2_contig_type ret = CONTIG_NONE;
+	u32 left_cpos, right_cpos;
+	struct ocfs2_extent_rec *rec = NULL;
+	struct ocfs2_extent_list *new_el;
+	struct ocfs2_path *left_path = NULL, *right_path = NULL;
+	struct buffer_head *bh;
+	struct ocfs2_extent_block *eb;
+	struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
+
+	if (index > 0) {
+		rec = &el->l_recs[index - 1];
+	} else if (path->p_tree_depth > 0) {
+		status = ocfs2_find_cpos_for_left_leaf(sb, path, &left_cpos);
+		if (status)
+			goto exit;
+
+		if (left_cpos != 0) {
+			left_path = ocfs2_new_path_from_path(path);
+			if (!left_path) {
+				status = -ENOMEM;
+				mlog_errno(status);
+				goto exit;
+			}
+
+			status = ocfs2_find_path(et->et_ci, left_path,
+						 left_cpos);
+			if (status)
+				goto free_left_path;
+
+			new_el = path_leaf_el(left_path);
+
+			if (le16_to_cpu(new_el->l_next_free_rec) !=
+			    le16_to_cpu(new_el->l_count)) {
+				bh = path_leaf_bh(left_path);
+				eb = (struct ocfs2_extent_block *)bh->b_data;
+				status = ocfs2_error(sb,
+						"Extent block #%llu has an invalid l_next_free_rec of %d.  It should have matched the l_count of %d\n",
+						(unsigned long long)le64_to_cpu(eb->h_blkno),
+						le16_to_cpu(new_el->l_next_free_rec),
+						le16_to_cpu(new_el->l_count));
+				goto free_left_path;
+			}
+			rec = &new_el->l_recs[
+				le16_to_cpu(new_el->l_next_free_rec) - 1];
+		}
+	}
+
+	/*
+	 * We're careful to check for an empty extent record here -
+	 * the merge code will know what to do if it sees one.
+	 */
+	if (rec) {
+		if (index == 1 && ocfs2_is_empty_extent(rec)) {
+			if (split_rec->e_cpos == el->l_recs[index].e_cpos)
+				ret = CONTIG_RIGHT;
+		} else {
+			ret = ocfs2_et_extent_contig(et, rec, split_rec);
+		}
+	}
+
+	rec = NULL;
+	if (index < (le16_to_cpu(el->l_next_free_rec) - 1))
+		rec = &el->l_recs[index + 1];
+	else if (le16_to_cpu(el->l_next_free_rec) == le16_to_cpu(el->l_count) &&
+		 path->p_tree_depth > 0) {
+		status = ocfs2_find_cpos_for_right_leaf(sb, path, &right_cpos);
+		if (status)
+			goto free_left_path;
+
+		if (right_cpos == 0)
+			goto free_left_path;
+
+		right_path = ocfs2_new_path_from_path(path);
+		if (!right_path) {
+			status = -ENOMEM;
+			mlog_errno(status);
+			goto free_left_path;
+		}
+
+		status = ocfs2_find_path(et->et_ci, right_path, right_cpos);
+		if (status)
+			goto free_right_path;
+
+		new_el = path_leaf_el(right_path);
+		rec = &new_el->l_recs[0];
+		if (ocfs2_is_empty_extent(rec)) {
+			if (le16_to_cpu(new_el->l_next_free_rec) <= 1) {
+				bh = path_leaf_bh(right_path);
+				eb = (struct ocfs2_extent_block *)bh->b_data;
+				status = ocfs2_error(sb,
+						"Extent block #%llu has an invalid l_next_free_rec of %d\n",
+						(unsigned long long)le64_to_cpu(eb->h_blkno),
+						le16_to_cpu(new_el->l_next_free_rec));
+				goto free_right_path;
+			}
+			rec = &new_el->l_recs[1];
+		}
+	}
+
+	if (rec) {
+		enum ocfs2_contig_type contig_type;
+
+		contig_type = ocfs2_et_extent_contig(et, rec, split_rec);
+
+		if (contig_type == CONTIG_LEFT && ret == CONTIG_RIGHT)
+			ret = CONTIG_LEFTRIGHT;
+		else if (ret == CONTIG_NONE)
+			ret = contig_type;
+	}
+
+free_right_path:
+	ocfs2_free_path(right_path);
+free_left_path:
+	ocfs2_free_path(left_path);
+exit:
+	if (status == 0)
+		ctxt->c_contig_type = ret;
+
+	return status;
+}
+
+static void ocfs2_figure_contig_type(struct ocfs2_extent_tree *et,
+				     struct ocfs2_insert_type *insert,
+				     struct ocfs2_extent_list *el,
+				     struct ocfs2_extent_rec *insert_rec)
+{
+	int i;
+	enum ocfs2_contig_type contig_type = CONTIG_NONE;
+
+	BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
+
+	for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
+		contig_type = ocfs2_et_extent_contig(et, &el->l_recs[i],
+						     insert_rec);
+		if (contig_type != CONTIG_NONE) {
+			insert->ins_contig_index = i;
+			break;
+		}
+	}
+	insert->ins_contig = contig_type;
+
+	if (insert->ins_contig != CONTIG_NONE) {
+		struct ocfs2_extent_rec *rec =
+				&el->l_recs[insert->ins_contig_index];
+		unsigned int len = le16_to_cpu(rec->e_leaf_clusters) +
+				   le16_to_cpu(insert_rec->e_leaf_clusters);
+
+		/*
+		 * Caller might want us to limit the size of extents, don't
+		 * calculate contiguousness if we might exceed that limit.
+		 */
+		if (et->et_max_leaf_clusters &&
+		    (len > et->et_max_leaf_clusters))
+			insert->ins_contig = CONTIG_NONE;
+	}
+}
+
+/*
+ * This should only be called against the righmost leaf extent list.
+ *
+ * ocfs2_figure_appending_type() will figure out whether we'll have to
+ * insert at the tail of the rightmost leaf.
+ *
+ * This should also work against the root extent list for tree's with 0
+ * depth. If we consider the root extent list to be the rightmost leaf node
+ * then the logic here makes sense.
+ */
+static void ocfs2_figure_appending_type(struct ocfs2_insert_type *insert,
+					struct ocfs2_extent_list *el,
+					struct ocfs2_extent_rec *insert_rec)
+{
+	int i;
+	u32 cpos = le32_to_cpu(insert_rec->e_cpos);
+	struct ocfs2_extent_rec *rec;
+
+	insert->ins_appending = APPEND_NONE;
+
+	BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
+
+	if (!el->l_next_free_rec)
+		goto set_tail_append;
+
+	if (ocfs2_is_empty_extent(&el->l_recs[0])) {
+		/* Were all records empty? */
+		if (le16_to_cpu(el->l_next_free_rec) == 1)
+			goto set_tail_append;
+	}
+
+	i = le16_to_cpu(el->l_next_free_rec) - 1;
+	rec = &el->l_recs[i];
+
+	if (cpos >=
+	    (le32_to_cpu(rec->e_cpos) + le16_to_cpu(rec->e_leaf_clusters)))
+		goto set_tail_append;
+
+	return;
+
+set_tail_append:
+	insert->ins_appending = APPEND_TAIL;
+}
+
+/*
+ * Helper function called at the beginning of an insert.
+ *
+ * This computes a few things that are commonly used in the process of
+ * inserting into the btree:
+ *   - Whether the new extent is contiguous with an existing one.
+ *   - The current tree depth.
+ *   - Whether the insert is an appending one.
+ *   - The total # of free records in the tree.
+ *
+ * All of the information is stored on the ocfs2_insert_type
+ * structure.
+ */
+static int ocfs2_figure_insert_type(struct ocfs2_extent_tree *et,
+				    struct buffer_head **last_eb_bh,
+				    struct ocfs2_extent_rec *insert_rec,
+				    int *free_records,
+				    struct ocfs2_insert_type *insert)
+{
+	int ret;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_path *path = NULL;
+	struct buffer_head *bh = NULL;
+
+	insert->ins_split = SPLIT_NONE;
+
+	el = et->et_root_el;
+	insert->ins_tree_depth = le16_to_cpu(el->l_tree_depth);
+
+	if (el->l_tree_depth) {
+		/*
+		 * If we have tree depth, we read in the
+		 * rightmost extent block ahead of time as
+		 * ocfs2_figure_insert_type() and ocfs2_add_branch()
+		 * may want it later.
+		 */
+		ret = ocfs2_read_extent_block(et->et_ci,
+					      ocfs2_et_get_last_eb_blk(et),
+					      &bh);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+		eb = (struct ocfs2_extent_block *) bh->b_data;
+		el = &eb->h_list;
+	}
+
+	/*
+	 * Unless we have a contiguous insert, we'll need to know if
+	 * there is room left in our allocation tree for another
+	 * extent record.
+	 *
+	 * XXX: This test is simplistic, we can search for empty
+	 * extent records too.
+	 */
+	*free_records = le16_to_cpu(el->l_count) -
+		le16_to_cpu(el->l_next_free_rec);
+
+	if (!insert->ins_tree_depth) {
+		ocfs2_figure_contig_type(et, insert, el, insert_rec);
+		ocfs2_figure_appending_type(insert, el, insert_rec);
+		return 0;
+	}
+
+	path = ocfs2_new_path_from_et(et);
+	if (!path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * In the case that we're inserting past what the tree
+	 * currently accounts for, ocfs2_find_path() will return for
+	 * us the rightmost tree path. This is accounted for below in
+	 * the appending code.
+	 */
+	ret = ocfs2_find_path(et->et_ci, path, le32_to_cpu(insert_rec->e_cpos));
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	el = path_leaf_el(path);
+
+	/*
+	 * Now that we have the path, there's two things we want to determine:
+	 * 1) Contiguousness (also set contig_index if this is so)
+	 *
+	 * 2) Are we doing an append? We can trivially break this up
+         *     into two types of appends: simple record append, or a
+         *     rotate inside the tail leaf.
+	 */
+	ocfs2_figure_contig_type(et, insert, el, insert_rec);
+
+	/*
+	 * The insert code isn't quite ready to deal with all cases of
+	 * left contiguousness. Specifically, if it's an insert into
+	 * the 1st record in a leaf, it will require the adjustment of
+	 * cluster count on the last record of the path directly to it's
+	 * left. For now, just catch that case and fool the layers
+	 * above us. This works just fine for tree_depth == 0, which
+	 * is why we allow that above.
+	 */
+	if (insert->ins_contig == CONTIG_LEFT &&
+	    insert->ins_contig_index == 0)
+		insert->ins_contig = CONTIG_NONE;
+
+	/*
+	 * Ok, so we can simply compare against last_eb to figure out
+	 * whether the path doesn't exist. This will only happen in
+	 * the case that we're doing a tail append, so maybe we can
+	 * take advantage of that information somehow.
+	 */
+	if (ocfs2_et_get_last_eb_blk(et) ==
+	    path_leaf_bh(path)->b_blocknr) {
+		/*
+		 * Ok, ocfs2_find_path() returned us the rightmost
+		 * tree path. This might be an appending insert. There are
+		 * two cases:
+		 *    1) We're doing a true append at the tail:
+		 *	-This might even be off the end of the leaf
+		 *    2) We're "appending" by rotating in the tail
+		 */
+		ocfs2_figure_appending_type(insert, el, insert_rec);
+	}
+
+out:
+	ocfs2_free_path(path);
+
+	if (ret == 0)
+		*last_eb_bh = bh;
+	else
+		brelse(bh);
+	return ret;
+}
+
+/*
+ * Insert an extent into a btree.
+ *
+ * The caller needs to update the owning btree's cluster count.
+ */
+int ocfs2_insert_extent(handle_t *handle,
+			struct ocfs2_extent_tree *et,
+			u32 cpos,
+			u64 start_blk,
+			u32 new_clusters,
+			u8 flags,
+			struct ocfs2_alloc_context *meta_ac)
+{
+	int status;
+	int free_records;
+	struct buffer_head *last_eb_bh = NULL;
+	struct ocfs2_insert_type insert = {0, };
+	struct ocfs2_extent_rec rec;
+
+	trace_ocfs2_insert_extent_start(
+		(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+		cpos, new_clusters);
+
+	memset(&rec, 0, sizeof(rec));
+	rec.e_cpos = cpu_to_le32(cpos);
+	rec.e_blkno = cpu_to_le64(start_blk);
+	rec.e_leaf_clusters = cpu_to_le16(new_clusters);
+	rec.e_flags = flags;
+	status = ocfs2_et_insert_check(et, &rec);
+	if (status) {
+		mlog_errno(status);
+		goto bail;
+	}
+
+	status = ocfs2_figure_insert_type(et, &last_eb_bh, &rec,
+					  &free_records, &insert);
+	if (status < 0) {
+		mlog_errno(status);
+		goto bail;
+	}
+
+	trace_ocfs2_insert_extent(insert.ins_appending, insert.ins_contig,
+				  insert.ins_contig_index, free_records,
+				  insert.ins_tree_depth);
+
+	if (insert.ins_contig == CONTIG_NONE && free_records == 0) {
+		status = ocfs2_grow_tree(handle, et,
+					 &insert.ins_tree_depth, &last_eb_bh,
+					 meta_ac);
+		if (status) {
+			mlog_errno(status);
+			goto bail;
+		}
+	}
+
+	/* Finally, we can add clusters. This might rotate the tree for us. */
+	status = ocfs2_do_insert_extent(handle, et, &rec, &insert);
+	if (status < 0)
+		mlog_errno(status);
+	else
+		ocfs2_et_extent_map_insert(et, &rec);
+
+bail:
+	brelse(last_eb_bh);
+
+	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 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.
+ */
+int ocfs2_add_clusters_in_btree(handle_t *handle,
+				struct ocfs2_extent_tree *et,
+				u32 *logical_offset,
+				u32 clusters_to_add,
+				int mark_unwritten,
+				struct ocfs2_alloc_context *data_ac,
+				struct ocfs2_alloc_context *meta_ac,
+				enum ocfs2_alloc_restarted *reason_ret)
+{
+	int status = 0, err = 0;
+	int need_free = 0;
+	int free_extents;
+	enum ocfs2_alloc_restarted reason = RESTART_NONE;
+	u32 bit_off, num_bits;
+	u64 block;
+	u8 flags = 0;
+	struct ocfs2_super *osb =
+		OCFS2_SB(ocfs2_metadata_cache_get_super(et->et_ci));
+
+	BUG_ON(!clusters_to_add);
+
+	if (mark_unwritten)
+		flags = OCFS2_EXT_UNWRITTEN;
+
+	free_extents = ocfs2_num_free_extents(et);
+	if (free_extents < 0) {
+		status = free_extents;
+		mlog_errno(status);
+		goto leave;
+	}
+
+	/* there are two cases which could cause us to EAGAIN in the
+	 * we-need-more-metadata case:
+	 * 1) we haven't reserved *any*
+	 * 2) we are so fragmented, we've needed to add metadata too
+	 *    many times. */
+	if (!free_extents && !meta_ac) {
+		err = -1;
+		status = -EAGAIN;
+		reason = RESTART_META;
+		goto leave;
+	} else if ((!free_extents)
+		   && (ocfs2_alloc_context_bits_left(meta_ac)
+		       < ocfs2_extend_meta_needed(et->et_root_el))) {
+		err = -2;
+		status = -EAGAIN;
+		reason = RESTART_META;
+		goto leave;
+	}
+
+	status = __ocfs2_claim_clusters(handle, data_ac, 1,
+					clusters_to_add, &bit_off, &num_bits);
+	if (status < 0) {
+		if (status != -ENOSPC)
+			mlog_errno(status);
+		goto leave;
+	}
+
+	BUG_ON(num_bits > clusters_to_add);
+
+	/* reserve our write early -- insert_extent may update the tree root */
+	status = ocfs2_et_root_journal_access(handle, et,
+					      OCFS2_JOURNAL_ACCESS_WRITE);
+	if (status < 0) {
+		mlog_errno(status);
+		need_free = 1;
+		goto bail;
+	}
+
+	block = ocfs2_clusters_to_blocks(osb->sb, bit_off);
+	trace_ocfs2_add_clusters_in_btree(
+	     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+	     bit_off, num_bits);
+	status = ocfs2_insert_extent(handle, et, *logical_offset, block,
+				     num_bits, flags, meta_ac);
+	if (status < 0) {
+		mlog_errno(status);
+		need_free = 1;
+		goto bail;
+	}
+
+	ocfs2_journal_dirty(handle, et->et_root_bh);
+
+	clusters_to_add -= num_bits;
+	*logical_offset += num_bits;
+
+	if (clusters_to_add) {
+		err = clusters_to_add;
+		status = -EAGAIN;
+		reason = RESTART_TRANS;
+	}
+
+bail:
+	if (need_free) {
+		if (data_ac->ac_which == OCFS2_AC_USE_LOCAL)
+			ocfs2_free_local_alloc_bits(osb, handle, data_ac,
+					bit_off, num_bits);
+		else
+			ocfs2_free_clusters(handle,
+					data_ac->ac_inode,
+					data_ac->ac_bh,
+					ocfs2_clusters_to_blocks(osb->sb, bit_off),
+					num_bits);
+	}
+
+leave:
+	if (reason_ret)
+		*reason_ret = reason;
+	trace_ocfs2_add_clusters_in_btree_ret(status, reason, err);
+	return status;
+}
+
+static void ocfs2_make_right_split_rec(struct super_block *sb,
+				       struct ocfs2_extent_rec *split_rec,
+				       u32 cpos,
+				       struct ocfs2_extent_rec *rec)
+{
+	u32 rec_cpos = le32_to_cpu(rec->e_cpos);
+	u32 rec_range = rec_cpos + le16_to_cpu(rec->e_leaf_clusters);
+
+	memset(split_rec, 0, sizeof(struct ocfs2_extent_rec));
+
+	split_rec->e_cpos = cpu_to_le32(cpos);
+	split_rec->e_leaf_clusters = cpu_to_le16(rec_range - cpos);
+
+	split_rec->e_blkno = rec->e_blkno;
+	le64_add_cpu(&split_rec->e_blkno,
+		     ocfs2_clusters_to_blocks(sb, cpos - rec_cpos));
+
+	split_rec->e_flags = rec->e_flags;
+}
+
+static int ocfs2_split_and_insert(handle_t *handle,
+				  struct ocfs2_extent_tree *et,
+				  struct ocfs2_path *path,
+				  struct buffer_head **last_eb_bh,
+				  int split_index,
+				  struct ocfs2_extent_rec *orig_split_rec,
+				  struct ocfs2_alloc_context *meta_ac)
+{
+	int ret = 0, depth;
+	unsigned int insert_range, rec_range, do_leftright = 0;
+	struct ocfs2_extent_rec tmprec;
+	struct ocfs2_extent_list *rightmost_el;
+	struct ocfs2_extent_rec rec;
+	struct ocfs2_extent_rec split_rec = *orig_split_rec;
+	struct ocfs2_insert_type insert;
+	struct ocfs2_extent_block *eb;
+
+leftright:
+	/*
+	 * Store a copy of the record on the stack - it might move
+	 * around as the tree is manipulated below.
+	 */
+	rec = path_leaf_el(path)->l_recs[split_index];
+
+	rightmost_el = et->et_root_el;
+
+	depth = le16_to_cpu(rightmost_el->l_tree_depth);
+	if (depth) {
+		BUG_ON(!(*last_eb_bh));
+		eb = (struct ocfs2_extent_block *) (*last_eb_bh)->b_data;
+		rightmost_el = &eb->h_list;
+	}
+
+	if (le16_to_cpu(rightmost_el->l_next_free_rec) ==
+	    le16_to_cpu(rightmost_el->l_count)) {
+		ret = ocfs2_grow_tree(handle, et,
+				      &depth, last_eb_bh, meta_ac);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+	memset(&insert, 0, sizeof(struct ocfs2_insert_type));
+	insert.ins_appending = APPEND_NONE;
+	insert.ins_contig = CONTIG_NONE;
+	insert.ins_tree_depth = depth;
+
+	insert_range = le32_to_cpu(split_rec.e_cpos) +
+		le16_to_cpu(split_rec.e_leaf_clusters);
+	rec_range = le32_to_cpu(rec.e_cpos) +
+		le16_to_cpu(rec.e_leaf_clusters);
+
+	if (split_rec.e_cpos == rec.e_cpos) {
+		insert.ins_split = SPLIT_LEFT;
+	} else if (insert_range == rec_range) {
+		insert.ins_split = SPLIT_RIGHT;
+	} else {
+		/*
+		 * Left/right split. We fake this as a right split
+		 * first and then make a second pass as a left split.
+		 */
+		insert.ins_split = SPLIT_RIGHT;
+
+		ocfs2_make_right_split_rec(ocfs2_metadata_cache_get_super(et->et_ci),
+					   &tmprec, insert_range, &rec);
+
+		split_rec = tmprec;
+
+		BUG_ON(do_leftright);
+		do_leftright = 1;
+	}
+
+	ret = ocfs2_do_insert_extent(handle, et, &split_rec, &insert);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (do_leftright == 1) {
+		u32 cpos;
+		struct ocfs2_extent_list *el;
+
+		do_leftright++;
+		split_rec = *orig_split_rec;
+
+		ocfs2_reinit_path(path, 1);
+
+		cpos = le32_to_cpu(split_rec.e_cpos);
+		ret = ocfs2_find_path(et->et_ci, path, cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		el = path_leaf_el(path);
+		split_index = ocfs2_search_extent_list(el, cpos);
+		if (split_index == -1) {
+			ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+				    "Owner %llu has an extent at cpos %u which can no longer be found\n",
+				    (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+				    cpos);
+			ret = -EROFS;
+			goto out;
+		}
+		goto leftright;
+	}
+out:
+
+	return ret;
+}
+
+static int ocfs2_replace_extent_rec(handle_t *handle,
+				    struct ocfs2_extent_tree *et,
+				    struct ocfs2_path *path,
+				    struct ocfs2_extent_list *el,
+				    int split_index,
+				    struct ocfs2_extent_rec *split_rec)
+{
+	int ret;
+
+	ret = ocfs2_path_bh_journal_access(handle, et->et_ci, path,
+					   path_num_items(path) - 1);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	el->l_recs[split_index] = *split_rec;
+
+	ocfs2_journal_dirty(handle, path_leaf_bh(path));
+out:
+	return ret;
+}
+
+/*
+ * Split part or all of the extent record at split_index in the leaf
+ * pointed to by path. Merge with the contiguous extent record if needed.
+ *
+ * Care is taken to handle contiguousness so as to not grow the tree.
+ *
+ * meta_ac is not strictly necessary - we only truly need it if growth
+ * of the tree is required. All other cases will degrade into a less
+ * optimal tree layout.
+ *
+ * last_eb_bh should be the rightmost leaf block for any extent
+ * btree. Since a split may grow the tree or a merge might shrink it,
+ * the caller cannot trust the contents of that buffer after this call.
+ *
+ * This code is optimized for readability - several passes might be
+ * made over certain portions of the tree. All of those blocks will
+ * have been brought into cache (and pinned via the journal), so the
+ * extra overhead is not expressed in terms of disk reads.
+ */
+int ocfs2_split_extent(handle_t *handle,
+		       struct ocfs2_extent_tree *et,
+		       struct ocfs2_path *path,
+		       int split_index,
+		       struct ocfs2_extent_rec *split_rec,
+		       struct ocfs2_alloc_context *meta_ac,
+		       struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+	int ret = 0;
+	struct ocfs2_extent_list *el = path_leaf_el(path);
+	struct buffer_head *last_eb_bh = NULL;
+	struct ocfs2_extent_rec *rec = &el->l_recs[split_index];
+	struct ocfs2_merge_ctxt ctxt;
+
+	if (le32_to_cpu(rec->e_cpos) > le32_to_cpu(split_rec->e_cpos) ||
+	    ((le32_to_cpu(rec->e_cpos) + le16_to_cpu(rec->e_leaf_clusters)) <
+	     (le32_to_cpu(split_rec->e_cpos) + le16_to_cpu(split_rec->e_leaf_clusters)))) {
+		ret = -EIO;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_figure_merge_contig_type(et, path, el,
+					     split_index,
+					     split_rec,
+					     &ctxt);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * The core merge / split code wants to know how much room is
+	 * left in this allocation tree, so we pass the
+	 * rightmost extent list.
+	 */
+	if (path->p_tree_depth) {
+		ret = ocfs2_read_extent_block(et->et_ci,
+					      ocfs2_et_get_last_eb_blk(et),
+					      &last_eb_bh);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+	if (rec->e_cpos == split_rec->e_cpos &&
+	    rec->e_leaf_clusters == split_rec->e_leaf_clusters)
+		ctxt.c_split_covers_rec = 1;
+	else
+		ctxt.c_split_covers_rec = 0;
+
+	ctxt.c_has_empty_extent = ocfs2_is_empty_extent(&el->l_recs[0]);
+
+	trace_ocfs2_split_extent(split_index, ctxt.c_contig_type,
+				 ctxt.c_has_empty_extent,
+				 ctxt.c_split_covers_rec);
+
+	if (ctxt.c_contig_type == CONTIG_NONE) {
+		if (ctxt.c_split_covers_rec)
+			ret = ocfs2_replace_extent_rec(handle, et, path, el,
+						       split_index, split_rec);
+		else
+			ret = ocfs2_split_and_insert(handle, et, path,
+						     &last_eb_bh, split_index,
+						     split_rec, meta_ac);
+		if (ret)
+			mlog_errno(ret);
+	} else {
+		ret = ocfs2_try_to_merge_extent(handle, et, path,
+						split_index, split_rec,
+						dealloc, &ctxt);
+		if (ret)
+			mlog_errno(ret);
+	}
+
+out:
+	brelse(last_eb_bh);
+	return ret;
+}
+
+/*
+ * Change the flags of the already-existing extent at cpos for len clusters.
+ *
+ * new_flags: the flags we want to set.
+ * clear_flags: the flags we want to clear.
+ * phys: the new physical offset we want this new extent starts from.
+ *
+ * If the existing extent is larger than the request, initiate a
+ * split. An attempt will be made at merging with adjacent extents.
+ *
+ * The caller is responsible for passing down meta_ac if we'll need it.
+ */
+int ocfs2_change_extent_flag(handle_t *handle,
+			     struct ocfs2_extent_tree *et,
+			     u32 cpos, u32 len, u32 phys,
+			     struct ocfs2_alloc_context *meta_ac,
+			     struct ocfs2_cached_dealloc_ctxt *dealloc,
+			     int new_flags, int clear_flags)
+{
+	int ret, index;
+	struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
+	u64 start_blkno = ocfs2_clusters_to_blocks(sb, phys);
+	struct ocfs2_extent_rec split_rec;
+	struct ocfs2_path *left_path = NULL;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_extent_rec *rec;
+
+	left_path = ocfs2_new_path_from_et(et);
+	if (!left_path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_find_path(et->et_ci, left_path, cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+	el = path_leaf_el(left_path);
+
+	index = ocfs2_search_extent_list(el, cpos);
+	if (index == -1) {
+		ocfs2_error(sb,
+			    "Owner %llu has an extent at cpos %u which can no longer be found\n",
+			    (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+			    cpos);
+		ret = -EROFS;
+		goto out;
+	}
+
+	ret = -EIO;
+	rec = &el->l_recs[index];
+	if (new_flags && (rec->e_flags & new_flags)) {
+		mlog(ML_ERROR, "Owner %llu tried to set %d flags on an "
+		     "extent that already had them\n",
+		     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+		     new_flags);
+		goto out;
+	}
+
+	if (clear_flags && !(rec->e_flags & clear_flags)) {
+		mlog(ML_ERROR, "Owner %llu tried to clear %d flags on an "
+		     "extent that didn't have them\n",
+		     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+		     clear_flags);
+		goto out;
+	}
+
+	memset(&split_rec, 0, sizeof(struct ocfs2_extent_rec));
+	split_rec.e_cpos = cpu_to_le32(cpos);
+	split_rec.e_leaf_clusters = cpu_to_le16(len);
+	split_rec.e_blkno = cpu_to_le64(start_blkno);
+	split_rec.e_flags = rec->e_flags;
+	if (new_flags)
+		split_rec.e_flags |= new_flags;
+	if (clear_flags)
+		split_rec.e_flags &= ~clear_flags;
+
+	ret = ocfs2_split_extent(handle, et, left_path,
+				 index, &split_rec, meta_ac,
+				 dealloc);
+	if (ret)
+		mlog_errno(ret);
+
+out:
+	ocfs2_free_path(left_path);
+	return ret;
+
+}
+
+/*
+ * Mark the already-existing extent at cpos as written for len clusters.
+ * This removes the unwritten extent flag.
+ *
+ * If the existing extent is larger than the request, initiate a
+ * split. An attempt will be made at merging with adjacent extents.
+ *
+ * The caller is responsible for passing down meta_ac if we'll need it.
+ */
+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)
+{
+	int ret;
+
+	trace_ocfs2_mark_extent_written(
+		(unsigned long long)OCFS2_I(inode)->ip_blkno,
+		cpos, len, phys);
+
+	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 is not set in the super block\n",
+			    (unsigned long long)OCFS2_I(inode)->ip_blkno);
+		ret = -EROFS;
+		goto out;
+	}
+
+	/*
+	 * XXX: This should be fixed up so that we just re-insert the
+	 * next extent records.
+	 */
+	ocfs2_et_extent_map_truncate(et, 0);
+
+	ret = ocfs2_change_extent_flag(handle, et, cpos,
+				       len, phys, meta_ac, dealloc,
+				       0, OCFS2_EXT_UNWRITTEN);
+	if (ret)
+		mlog_errno(ret);
+
+out:
+	return ret;
+}
+
+static int ocfs2_split_tree(handle_t *handle, struct ocfs2_extent_tree *et,
+			    struct ocfs2_path *path,
+			    int index, u32 new_range,
+			    struct ocfs2_alloc_context *meta_ac)
+{
+	int ret, depth, credits;
+	struct buffer_head *last_eb_bh = NULL;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list *rightmost_el, *el;
+	struct ocfs2_extent_rec split_rec;
+	struct ocfs2_extent_rec *rec;
+	struct ocfs2_insert_type insert;
+
+	/*
+	 * Setup the record to split before we grow the tree.
+	 */
+	el = path_leaf_el(path);
+	rec = &el->l_recs[index];
+	ocfs2_make_right_split_rec(ocfs2_metadata_cache_get_super(et->et_ci),
+				   &split_rec, new_range, rec);
+
+	depth = path->p_tree_depth;
+	if (depth > 0) {
+		ret = ocfs2_read_extent_block(et->et_ci,
+					      ocfs2_et_get_last_eb_blk(et),
+					      &last_eb_bh);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
+		rightmost_el = &eb->h_list;
+	} else
+		rightmost_el = path_leaf_el(path);
+
+	credits = path->p_tree_depth +
+		  ocfs2_extend_meta_needed(et->et_root_el);
+	ret = ocfs2_extend_trans(handle, credits);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (le16_to_cpu(rightmost_el->l_next_free_rec) ==
+	    le16_to_cpu(rightmost_el->l_count)) {
+		ret = ocfs2_grow_tree(handle, et, &depth, &last_eb_bh,
+				      meta_ac);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+	memset(&insert, 0, sizeof(struct ocfs2_insert_type));
+	insert.ins_appending = APPEND_NONE;
+	insert.ins_contig = CONTIG_NONE;
+	insert.ins_split = SPLIT_RIGHT;
+	insert.ins_tree_depth = depth;
+
+	ret = ocfs2_do_insert_extent(handle, et, &split_rec, &insert);
+	if (ret)
+		mlog_errno(ret);
+
+out:
+	brelse(last_eb_bh);
+	return ret;
+}
+
+static int ocfs2_truncate_rec(handle_t *handle,
+			      struct ocfs2_extent_tree *et,
+			      struct ocfs2_path *path, int index,
+			      struct ocfs2_cached_dealloc_ctxt *dealloc,
+			      u32 cpos, u32 len)
+{
+	int ret;
+	u32 left_cpos, rec_range, trunc_range;
+	int is_rightmost_tree_rec = 0;
+	struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
+	struct ocfs2_path *left_path = NULL;
+	struct ocfs2_extent_list *el = path_leaf_el(path);
+	struct ocfs2_extent_rec *rec;
+	struct ocfs2_extent_block *eb;
+
+	if (ocfs2_is_empty_extent(&el->l_recs[0]) && index > 0) {
+		/* extend credit for ocfs2_remove_rightmost_path */
+		ret = ocfs2_extend_rotate_transaction(handle, 0,
+				jbd2_handle_buffer_credits(handle),
+				path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_rotate_tree_left(handle, et, path, dealloc);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		index--;
+	}
+
+	if (index == (le16_to_cpu(el->l_next_free_rec) - 1) &&
+	    path->p_tree_depth) {
+		/*
+		 * Check whether this is the rightmost tree record. If
+		 * we remove all of this record or part of its right
+		 * edge then an update of the record lengths above it
+		 * will be required.
+		 */
+		eb = (struct ocfs2_extent_block *)path_leaf_bh(path)->b_data;
+		if (eb->h_next_leaf_blk == 0)
+			is_rightmost_tree_rec = 1;
+	}
+
+	rec = &el->l_recs[index];
+	if (index == 0 && path->p_tree_depth &&
+	    le32_to_cpu(rec->e_cpos) == cpos) {
+		/*
+		 * Changing the leftmost offset (via partial or whole
+		 * record truncate) of an interior (or rightmost) path
+		 * means we have to update the subtree that is formed
+		 * by this leaf and the one to it's left.
+		 *
+		 * There are two cases we can skip:
+		 *   1) Path is the leftmost one in our btree.
+		 *   2) The leaf is rightmost and will be empty after
+		 *      we remove the extent record - the rotate code
+		 *      knows how to update the newly formed edge.
+		 */
+
+		ret = ocfs2_find_cpos_for_left_leaf(sb, path, &left_cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		if (left_cpos && le16_to_cpu(el->l_next_free_rec) > 1) {
+			left_path = ocfs2_new_path_from_path(path);
+			if (!left_path) {
+				ret = -ENOMEM;
+				mlog_errno(ret);
+				goto out;
+			}
+
+			ret = ocfs2_find_path(et->et_ci, left_path,
+					      left_cpos);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+		}
+	}
+
+	ret = ocfs2_extend_rotate_transaction(handle, 0,
+					jbd2_handle_buffer_credits(handle),
+					path);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_journal_access_path(et->et_ci, handle, path);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_journal_access_path(et->et_ci, handle, left_path);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	rec_range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
+	trunc_range = cpos + len;
+
+	if (le32_to_cpu(rec->e_cpos) == cpos && rec_range == trunc_range) {
+		int next_free;
+
+		memset(rec, 0, sizeof(*rec));
+		ocfs2_cleanup_merge(el, index);
+
+		next_free = le16_to_cpu(el->l_next_free_rec);
+		if (is_rightmost_tree_rec && next_free > 1) {
+			/*
+			 * We skip the edge update if this path will
+			 * be deleted by the rotate code.
+			 */
+			rec = &el->l_recs[next_free - 1];
+			ocfs2_adjust_rightmost_records(handle, et, path,
+						       rec);
+		}
+	} else if (le32_to_cpu(rec->e_cpos) == cpos) {
+		/* Remove leftmost portion of the record. */
+		le32_add_cpu(&rec->e_cpos, len);
+		le64_add_cpu(&rec->e_blkno, ocfs2_clusters_to_blocks(sb, len));
+		le16_add_cpu(&rec->e_leaf_clusters, -len);
+	} else if (rec_range == trunc_range) {
+		/* Remove rightmost portion of the record */
+		le16_add_cpu(&rec->e_leaf_clusters, -len);
+		if (is_rightmost_tree_rec)
+			ocfs2_adjust_rightmost_records(handle, et, path, rec);
+	} else {
+		/* Caller should have trapped this. */
+		mlog(ML_ERROR, "Owner %llu: Invalid record truncate: (%u, %u) "
+		     "(%u, %u)\n",
+		     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+		     le32_to_cpu(rec->e_cpos),
+		     le16_to_cpu(rec->e_leaf_clusters), cpos, len);
+		BUG();
+	}
+
+	if (left_path) {
+		int subtree_index;
+
+		subtree_index = ocfs2_find_subtree_root(et, left_path, path);
+		ocfs2_complete_edge_insert(handle, left_path, path,
+					   subtree_index);
+	}
+
+	ocfs2_journal_dirty(handle, path_leaf_bh(path));
+
+	ret = ocfs2_rotate_tree_left(handle, et, path, dealloc);
+	if (ret)
+		mlog_errno(ret);
+
+out:
+	ocfs2_free_path(left_path);
+	return ret;
+}
+
+int ocfs2_remove_extent(handle_t *handle,
+			struct ocfs2_extent_tree *et,
+			u32 cpos, u32 len,
+			struct ocfs2_alloc_context *meta_ac,
+			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;
+
+	/*
+	 * XXX: Why are we truncating to 0 instead of wherever this
+	 * affects us?
+	 */
+	ocfs2_et_extent_map_truncate(et, 0);
+
+	path = ocfs2_new_path_from_et(et);
+	if (!path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_find_path(et->et_ci, path, cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	el = path_leaf_el(path);
+	index = ocfs2_search_extent_list(el, cpos);
+	if (index == -1) {
+		ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+			    "Owner %llu has an extent at cpos %u which can no longer be found\n",
+			    (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+			    cpos);
+		ret = -EROFS;
+		goto out;
+	}
+
+	/*
+	 * We have 3 cases of extent removal:
+	 *   1) Range covers the entire extent rec
+	 *   2) Range begins or ends on one edge of the extent rec
+	 *   3) Range is in the middle of the extent rec (no shared edges)
+	 *
+	 * For case 1 we remove the extent rec and left rotate to
+	 * fill the hole.
+	 *
+	 * For case 2 we just shrink the existing extent rec, with a
+	 * tree update if the shrinking edge is also the edge of an
+	 * extent block.
+	 *
+	 * For case 3 we do a right split to turn the extent rec into
+	 * something case 2 can handle.
+	 */
+	rec = &el->l_recs[index];
+	rec_range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
+	trunc_range = cpos + len;
+
+	BUG_ON(cpos < le32_to_cpu(rec->e_cpos) || trunc_range > rec_range);
+
+	trace_ocfs2_remove_extent(
+		(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+		cpos, len, index, le32_to_cpu(rec->e_cpos),
+		ocfs2_rec_clusters(el, rec));
+
+	if (le32_to_cpu(rec->e_cpos) == cpos || rec_range == trunc_range) {
+		ret = ocfs2_truncate_rec(handle, et, path, index, dealloc,
+					 cpos, len);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	} else {
+		ret = ocfs2_split_tree(handle, et, path, index,
+				       trunc_range, meta_ac);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/*
+		 * The split could have manipulated the tree enough to
+		 * move the record location, so we have to look for it again.
+		 */
+		ocfs2_reinit_path(path, 1);
+
+		ret = ocfs2_find_path(et->et_ci, path, cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		el = path_leaf_el(path);
+		index = ocfs2_search_extent_list(el, cpos);
+		if (index == -1) {
+			ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+				    "Owner %llu: split at cpos %u lost record\n",
+				    (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+				    cpos);
+			ret = -EROFS;
+			goto out;
+		}
+
+		/*
+		 * Double check our values here. If anything is fishy,
+		 * it's easier to catch it at the top level.
+		 */
+		rec = &el->l_recs[index];
+		rec_range = le32_to_cpu(rec->e_cpos) +
+			ocfs2_rec_clusters(el, rec);
+		if (rec_range != trunc_range) {
+			ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+				    "Owner %llu: error after split at cpos %u trunc len %u, existing record is (%u,%u)\n",
+				    (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+				    cpos, len, le32_to_cpu(rec->e_cpos),
+				    ocfs2_rec_clusters(el, rec));
+			ret = -EROFS;
+			goto out;
+		}
+
+		ret = ocfs2_truncate_rec(handle, et, path, index, dealloc,
+					 cpos, len);
+		if (ret)
+			mlog_errno(ret);
+	}
+
+out:
+	ocfs2_free_path(path);
+	return ret;
+}
+
+/*
+ * ocfs2_reserve_blocks_for_rec_trunc() would look basically the
+ * same as ocfs2_lock_alloctors(), except for it accepts a blocks
+ * number to reserve some extra blocks, and it only handles meta
+ * data allocations.
+ *
+ * Currently, only ocfs2_remove_btree_range() uses it for truncating
+ * and punching holes.
+ */
+static int ocfs2_reserve_blocks_for_rec_trunc(struct inode *inode,
+					      struct ocfs2_extent_tree *et,
+					      u32 extents_to_split,
+					      struct ocfs2_alloc_context **ac,
+					      int extra_blocks)
+{
+	int ret = 0, num_free_extents;
+	unsigned int max_recs_needed = 2 * extents_to_split;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	*ac = NULL;
+
+	num_free_extents = ocfs2_num_free_extents(et);
+	if (num_free_extents < 0) {
+		ret = num_free_extents;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (!num_free_extents ||
+	    (ocfs2_sparse_alloc(osb) && num_free_extents < max_recs_needed))
+		extra_blocks += ocfs2_extend_meta_needed(et->et_root_el);
+
+	if (extra_blocks) {
+		ret = ocfs2_reserve_new_metadata_blocks(osb, extra_blocks, ac);
+		if (ret < 0) {
+			if (ret != -ENOSPC)
+				mlog_errno(ret);
+		}
+	}
+
+out:
+	if (ret) {
+		if (*ac) {
+			ocfs2_free_alloc_context(*ac);
+			*ac = NULL;
+		}
+	}
+
+	return ret;
+}
+
+int ocfs2_remove_btree_range(struct inode *inode,
+			     struct ocfs2_extent_tree *et,
+			     u32 cpos, u32 phys_cpos, u32 len, int flags,
+			     struct ocfs2_cached_dealloc_ctxt *dealloc,
+			     u64 refcount_loc, bool refcount_tree_locked)
+{
+	int ret, credits = 0, extra_blocks = 0;
+	u64 phys_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys_cpos);
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct inode *tl_inode = osb->osb_tl_inode;
+	handle_t *handle;
+	struct ocfs2_alloc_context *meta_ac = NULL;
+	struct ocfs2_refcount_tree *ref_tree = NULL;
+
+	if ((flags & OCFS2_EXT_REFCOUNTED) && len) {
+		BUG_ON(!ocfs2_is_refcount_inode(inode));
+
+		if (!refcount_tree_locked) {
+			ret = ocfs2_lock_refcount_tree(osb, refcount_loc, 1,
+						       &ref_tree, NULL);
+			if (ret) {
+				mlog_errno(ret);
+				goto bail;
+			}
+		}
+
+		ret = ocfs2_prepare_refcount_change_for_del(inode,
+							    refcount_loc,
+							    phys_blkno,
+							    len,
+							    &credits,
+							    &extra_blocks);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto bail;
+		}
+	}
+
+	ret = ocfs2_reserve_blocks_for_rec_trunc(inode, et, 1, &meta_ac,
+						 extra_blocks);
+	if (ret) {
+		mlog_errno(ret);
+		goto bail;
+	}
+
+	inode_lock(tl_inode);
+
+	if (ocfs2_truncate_log_needs_flush(osb)) {
+		ret = __ocfs2_flush_truncate_log(osb);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+	handle = ocfs2_start_trans(osb,
+			ocfs2_remove_extent_credits(osb->sb) + credits);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_et_root_journal_access(handle, et,
+					   OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	dquot_free_space_nodirty(inode,
+				  ocfs2_clusters_to_bytes(inode->i_sb, len));
+
+	ret = ocfs2_remove_extent(handle, et, cpos, len, meta_ac, dealloc);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	ocfs2_et_update_clusters(et, -len);
+	ocfs2_update_inode_fsync_trans(handle, inode, 1);
+
+	ocfs2_journal_dirty(handle, et->et_root_bh);
+
+	if (phys_blkno) {
+		if (flags & OCFS2_EXT_REFCOUNTED)
+			ret = ocfs2_decrease_refcount(inode, handle,
+					ocfs2_blocks_to_clusters(osb->sb,
+								 phys_blkno),
+					len, meta_ac,
+					dealloc, 1);
+		else
+			ret = ocfs2_truncate_log_append(osb, handle,
+							phys_blkno, len);
+		if (ret)
+			mlog_errno(ret);
+
+	}
+
+out_commit:
+	ocfs2_commit_trans(osb, handle);
+out:
+	inode_unlock(tl_inode);
+bail:
+	if (meta_ac)
+		ocfs2_free_alloc_context(meta_ac);
+
+	if (ref_tree)
+		ocfs2_unlock_refcount_tree(osb, ref_tree, 1);
+
+	return ret;
+}
+
+int ocfs2_truncate_log_needs_flush(struct ocfs2_super *osb)
+{
+	struct buffer_head *tl_bh = osb->osb_tl_bh;
+	struct ocfs2_dinode *di;
+	struct ocfs2_truncate_log *tl;
+
+	di = (struct ocfs2_dinode *) tl_bh->b_data;
+	tl = &di->id2.i_dealloc;
+
+	mlog_bug_on_msg(le16_to_cpu(tl->tl_used) > le16_to_cpu(tl->tl_count),
+			"slot %d, invalid truncate log parameters: used = "
+			"%u, count = %u\n", osb->slot_num,
+			le16_to_cpu(tl->tl_used), le16_to_cpu(tl->tl_count));
+	return le16_to_cpu(tl->tl_used) == le16_to_cpu(tl->tl_count);
+}
+
+static int ocfs2_truncate_log_can_coalesce(struct ocfs2_truncate_log *tl,
+					   unsigned int new_start)
+{
+	unsigned int tail_index;
+	unsigned int current_tail;
+
+	/* No records, nothing to coalesce */
+	if (!le16_to_cpu(tl->tl_used))
+		return 0;
+
+	tail_index = le16_to_cpu(tl->tl_used) - 1;
+	current_tail = le32_to_cpu(tl->tl_recs[tail_index].t_start);
+	current_tail += le32_to_cpu(tl->tl_recs[tail_index].t_clusters);
+
+	return current_tail == new_start;
+}
+
+int ocfs2_truncate_log_append(struct ocfs2_super *osb,
+			      handle_t *handle,
+			      u64 start_blk,
+			      unsigned int num_clusters)
+{
+	int status, index;
+	unsigned int start_cluster, tl_count;
+	struct inode *tl_inode = osb->osb_tl_inode;
+	struct buffer_head *tl_bh = osb->osb_tl_bh;
+	struct ocfs2_dinode *di;
+	struct ocfs2_truncate_log *tl;
+
+	BUG_ON(inode_trylock(tl_inode));
+
+	start_cluster = ocfs2_blocks_to_clusters(osb->sb, start_blk);
+
+	di = (struct ocfs2_dinode *) tl_bh->b_data;
+
+	/* tl_bh is loaded from ocfs2_truncate_log_init().  It's validated
+	 * by the underlying call to ocfs2_read_inode_block(), so any
+	 * corruption is a code bug */
+	BUG_ON(!OCFS2_IS_VALID_DINODE(di));
+
+	tl = &di->id2.i_dealloc;
+	tl_count = le16_to_cpu(tl->tl_count);
+	mlog_bug_on_msg(tl_count > ocfs2_truncate_recs_per_inode(osb->sb) ||
+			tl_count == 0,
+			"Truncate record count on #%llu invalid "
+			"wanted %u, actual %u\n",
+			(unsigned long long)OCFS2_I(tl_inode)->ip_blkno,
+			ocfs2_truncate_recs_per_inode(osb->sb),
+			le16_to_cpu(tl->tl_count));
+
+	/* Caller should have known to flush before calling us. */
+	index = le16_to_cpu(tl->tl_used);
+	if (index >= tl_count) {
+		status = -ENOSPC;
+		mlog_errno(status);
+		goto bail;
+	}
+
+	status = ocfs2_journal_access_di(handle, INODE_CACHE(tl_inode), tl_bh,
+					 OCFS2_JOURNAL_ACCESS_WRITE);
+	if (status < 0) {
+		mlog_errno(status);
+		goto bail;
+	}
+
+	trace_ocfs2_truncate_log_append(
+		(unsigned long long)OCFS2_I(tl_inode)->ip_blkno, index,
+		start_cluster, num_clusters);
+	if (ocfs2_truncate_log_can_coalesce(tl, start_cluster)) {
+		/*
+		 * Move index back to the record we are coalescing with.
+		 * ocfs2_truncate_log_can_coalesce() guarantees nonzero
+		 */
+		index--;
+
+		num_clusters += le32_to_cpu(tl->tl_recs[index].t_clusters);
+		trace_ocfs2_truncate_log_append(
+			(unsigned long long)OCFS2_I(tl_inode)->ip_blkno,
+			index, le32_to_cpu(tl->tl_recs[index].t_start),
+			num_clusters);
+	} else {
+		tl->tl_recs[index].t_start = cpu_to_le32(start_cluster);
+		tl->tl_used = cpu_to_le16(index + 1);
+	}
+	tl->tl_recs[index].t_clusters = cpu_to_le32(num_clusters);
+
+	ocfs2_journal_dirty(handle, tl_bh);
+
+	osb->truncated_clusters += num_clusters;
+bail:
+	return status;
+}
+
+static int ocfs2_replay_truncate_records(struct ocfs2_super *osb,
+					 struct inode *data_alloc_inode,
+					 struct buffer_head *data_alloc_bh)
+{
+	int status = 0;
+	int i;
+	unsigned int num_clusters;
+	u64 start_blk;
+	struct ocfs2_truncate_rec rec;
+	struct ocfs2_dinode *di;
+	struct ocfs2_truncate_log *tl;
+	struct inode *tl_inode = osb->osb_tl_inode;
+	struct buffer_head *tl_bh = osb->osb_tl_bh;
+	handle_t *handle;
+
+	di = (struct ocfs2_dinode *) tl_bh->b_data;
+	tl = &di->id2.i_dealloc;
+	i = le16_to_cpu(tl->tl_used) - 1;
+	while (i >= 0) {
+		handle = ocfs2_start_trans(osb, OCFS2_TRUNCATE_LOG_FLUSH_ONE_REC);
+		if (IS_ERR(handle)) {
+			status = PTR_ERR(handle);
+			mlog_errno(status);
+			goto bail;
+		}
+
+		/* Caller has given us at least enough credits to
+		 * update the truncate log dinode */
+		status = ocfs2_journal_access_di(handle, INODE_CACHE(tl_inode), tl_bh,
+						 OCFS2_JOURNAL_ACCESS_WRITE);
+		if (status < 0) {
+			ocfs2_commit_trans(osb, handle);
+			mlog_errno(status);
+			goto bail;
+		}
+
+		tl->tl_used = cpu_to_le16(i);
+
+		ocfs2_journal_dirty(handle, tl_bh);
+
+		rec = tl->tl_recs[i];
+		start_blk = ocfs2_clusters_to_blocks(data_alloc_inode->i_sb,
+						    le32_to_cpu(rec.t_start));
+		num_clusters = le32_to_cpu(rec.t_clusters);
+
+		/* if start_blk is not set, we ignore the record as
+		 * invalid. */
+		if (start_blk) {
+			trace_ocfs2_replay_truncate_records(
+				(unsigned long long)OCFS2_I(tl_inode)->ip_blkno,
+				i, le32_to_cpu(rec.t_start), num_clusters);
+
+			status = ocfs2_free_clusters(handle, data_alloc_inode,
+						     data_alloc_bh, start_blk,
+						     num_clusters);
+			if (status < 0) {
+				ocfs2_commit_trans(osb, handle);
+				mlog_errno(status);
+				goto bail;
+			}
+		}
+
+		ocfs2_commit_trans(osb, handle);
+		i--;
+	}
+
+	osb->truncated_clusters = 0;
+
+bail:
+	return status;
+}
+
+/* Expects you to already be holding tl_inode->i_rwsem */
+int __ocfs2_flush_truncate_log(struct ocfs2_super *osb)
+{
+	int status;
+	unsigned int num_to_flush;
+	struct inode *tl_inode = osb->osb_tl_inode;
+	struct inode *data_alloc_inode = NULL;
+	struct buffer_head *tl_bh = osb->osb_tl_bh;
+	struct buffer_head *data_alloc_bh = NULL;
+	struct ocfs2_dinode *di;
+	struct ocfs2_truncate_log *tl;
+	struct ocfs2_journal *journal = osb->journal;
+
+	BUG_ON(inode_trylock(tl_inode));
+
+	di = (struct ocfs2_dinode *) tl_bh->b_data;
+
+	/* tl_bh is loaded from ocfs2_truncate_log_init().  It's validated
+	 * by the underlying call to ocfs2_read_inode_block(), so any
+	 * corruption is a code bug */
+	BUG_ON(!OCFS2_IS_VALID_DINODE(di));
+
+	tl = &di->id2.i_dealloc;
+	num_to_flush = le16_to_cpu(tl->tl_used);
+	trace_ocfs2_flush_truncate_log(
+		(unsigned long long)OCFS2_I(tl_inode)->ip_blkno,
+		num_to_flush);
+	if (!num_to_flush) {
+		status = 0;
+		goto out;
+	}
+
+	/* Appending truncate log(TA) and flushing truncate log(TF) are
+	 * two separated transactions. They can be both committed but not
+	 * checkpointed. If crash occurs then, both two transaction will be
+	 * replayed with several already released to global bitmap clusters.
+	 * Then truncate log will be replayed resulting in cluster double free.
+	 */
+	jbd2_journal_lock_updates(journal->j_journal);
+	status = jbd2_journal_flush(journal->j_journal, 0);
+	jbd2_journal_unlock_updates(journal->j_journal);
+	if (status < 0) {
+		mlog_errno(status);
+		goto out;
+	}
+
+	data_alloc_inode = ocfs2_get_system_file_inode(osb,
+						       GLOBAL_BITMAP_SYSTEM_INODE,
+						       OCFS2_INVALID_SLOT);
+	if (!data_alloc_inode) {
+		status = -EINVAL;
+		mlog(ML_ERROR, "Could not get bitmap inode!\n");
+		goto out;
+	}
+
+	inode_lock(data_alloc_inode);
+
+	status = ocfs2_inode_lock(data_alloc_inode, &data_alloc_bh, 1);
+	if (status < 0) {
+		mlog_errno(status);
+		goto out_mutex;
+	}
+
+	status = ocfs2_replay_truncate_records(osb, data_alloc_inode,
+					       data_alloc_bh);
+	if (status < 0)
+		mlog_errno(status);
+
+	brelse(data_alloc_bh);
+	ocfs2_inode_unlock(data_alloc_inode, 1);
+
+out_mutex:
+	inode_unlock(data_alloc_inode);
+	iput(data_alloc_inode);
+
+out:
+	return status;
+}
+
+int ocfs2_flush_truncate_log(struct ocfs2_super *osb)
+{
+	int status;
+	struct inode *tl_inode = osb->osb_tl_inode;
+
+	inode_lock(tl_inode);
+	status = __ocfs2_flush_truncate_log(osb);
+	inode_unlock(tl_inode);
+
+	return status;
+}
+
+static void ocfs2_truncate_log_worker(struct work_struct *work)
+{
+	int status;
+	struct ocfs2_super *osb =
+		container_of(work, struct ocfs2_super,
+			     osb_truncate_log_wq.work);
+
+	status = ocfs2_flush_truncate_log(osb);
+	if (status < 0)
+		mlog_errno(status);
+	else
+		ocfs2_init_steal_slots(osb);
+}
+
+#define OCFS2_TRUNCATE_LOG_FLUSH_INTERVAL (2 * HZ)
+void ocfs2_schedule_truncate_log_flush(struct ocfs2_super *osb,
+				       int cancel)
+{
+	if (osb->osb_tl_inode &&
+			atomic_read(&osb->osb_tl_disable) == 0) {
+		/* We want to push off log flushes while truncates are
+		 * still running. */
+		if (cancel)
+			cancel_delayed_work(&osb->osb_truncate_log_wq);
+
+		queue_delayed_work(osb->ocfs2_wq, &osb->osb_truncate_log_wq,
+				   OCFS2_TRUNCATE_LOG_FLUSH_INTERVAL);
+	}
+}
+
+/*
+ * Try to flush truncate logs if we can free enough clusters from it.
+ * As for return value, "< 0" means error, "0" no space and "1" means
+ * we have freed enough spaces and let the caller try to allocate again.
+ */
+int ocfs2_try_to_free_truncate_log(struct ocfs2_super *osb,
+					unsigned int needed)
+{
+	tid_t target;
+	int ret = 0;
+	unsigned int truncated_clusters;
+
+	inode_lock(osb->osb_tl_inode);
+	truncated_clusters = osb->truncated_clusters;
+	inode_unlock(osb->osb_tl_inode);
+
+	/*
+	 * Check whether we can succeed in allocating if we free
+	 * the truncate log.
+	 */
+	if (truncated_clusters < needed)
+		goto out;
+
+	ret = ocfs2_flush_truncate_log(osb);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (jbd2_journal_start_commit(osb->journal->j_journal, &target)) {
+		jbd2_log_wait_commit(osb->journal->j_journal, target);
+		ret = 1;
+	}
+out:
+	return ret;
+}
+
+static int ocfs2_get_truncate_log_info(struct ocfs2_super *osb,
+				       int slot_num,
+				       struct inode **tl_inode,
+				       struct buffer_head **tl_bh)
+{
+	int status;
+	struct inode *inode = NULL;
+	struct buffer_head *bh = NULL;
+
+	inode = ocfs2_get_system_file_inode(osb,
+					   TRUNCATE_LOG_SYSTEM_INODE,
+					   slot_num);
+	if (!inode) {
+		status = -EINVAL;
+		mlog(ML_ERROR, "Could not get load truncate log inode!\n");
+		goto bail;
+	}
+
+	status = ocfs2_read_inode_block(inode, &bh);
+	if (status < 0) {
+		iput(inode);
+		mlog_errno(status);
+		goto bail;
+	}
+
+	*tl_inode = inode;
+	*tl_bh    = bh;
+bail:
+	return status;
+}
+
+/* called during the 1st stage of node recovery. we stamp a clean
+ * truncate log and pass back a copy for processing later. if the
+ * truncate log does not require processing, a *tl_copy is set to
+ * NULL. */
+int ocfs2_begin_truncate_log_recovery(struct ocfs2_super *osb,
+				      int slot_num,
+				      struct ocfs2_dinode **tl_copy)
+{
+	int status;
+	struct inode *tl_inode = NULL;
+	struct buffer_head *tl_bh = NULL;
+	struct ocfs2_dinode *di;
+	struct ocfs2_truncate_log *tl;
+
+	*tl_copy = NULL;
+
+	trace_ocfs2_begin_truncate_log_recovery(slot_num);
+
+	status = ocfs2_get_truncate_log_info(osb, slot_num, &tl_inode, &tl_bh);
+	if (status < 0) {
+		mlog_errno(status);
+		goto bail;
+	}
+
+	di = (struct ocfs2_dinode *) tl_bh->b_data;
+
+	/* tl_bh is loaded from ocfs2_get_truncate_log_info().  It's
+	 * validated by the underlying call to ocfs2_read_inode_block(),
+	 * so any corruption is a code bug */
+	BUG_ON(!OCFS2_IS_VALID_DINODE(di));
+
+	tl = &di->id2.i_dealloc;
+	if (le16_to_cpu(tl->tl_used)) {
+		trace_ocfs2_truncate_log_recovery_num(le16_to_cpu(tl->tl_used));
+
+		/*
+		 * Assuming the write-out below goes well, this copy will be
+		 * passed back to recovery for processing.
+		 */
+		*tl_copy = kmemdup(tl_bh->b_data, tl_bh->b_size, GFP_KERNEL);
+		if (!(*tl_copy)) {
+			status = -ENOMEM;
+			mlog_errno(status);
+			goto bail;
+		}
+
+		/* All we need to do to clear the truncate log is set
+		 * tl_used. */
+		tl->tl_used = 0;
+
+		ocfs2_compute_meta_ecc(osb->sb, tl_bh->b_data, &di->i_check);
+		status = ocfs2_write_block(osb, tl_bh, INODE_CACHE(tl_inode));
+		if (status < 0) {
+			mlog_errno(status);
+			goto bail;
+		}
+	}
+
+bail:
+	iput(tl_inode);
+	brelse(tl_bh);
+
+	if (status < 0) {
+		kfree(*tl_copy);
+		*tl_copy = NULL;
+		mlog_errno(status);
+	}
+
+	return status;
+}
+
+int ocfs2_complete_truncate_log_recovery(struct ocfs2_super *osb,
+					 struct ocfs2_dinode *tl_copy)
+{
+	int status = 0;
+	int i;
+	unsigned int clusters, num_recs, start_cluster;
+	u64 start_blk;
+	handle_t *handle;
+	struct inode *tl_inode = osb->osb_tl_inode;
+	struct ocfs2_truncate_log *tl;
+
+	if (OCFS2_I(tl_inode)->ip_blkno == le64_to_cpu(tl_copy->i_blkno)) {
+		mlog(ML_ERROR, "Asked to recover my own truncate log!\n");
+		return -EINVAL;
+	}
+
+	tl = &tl_copy->id2.i_dealloc;
+	num_recs = le16_to_cpu(tl->tl_used);
+	trace_ocfs2_complete_truncate_log_recovery(
+		(unsigned long long)le64_to_cpu(tl_copy->i_blkno),
+		num_recs);
+
+	inode_lock(tl_inode);
+	for(i = 0; i < num_recs; i++) {
+		if (ocfs2_truncate_log_needs_flush(osb)) {
+			status = __ocfs2_flush_truncate_log(osb);
+			if (status < 0) {
+				mlog_errno(status);
+				goto bail_up;
+			}
+		}
+
+		handle = ocfs2_start_trans(osb, OCFS2_TRUNCATE_LOG_UPDATE);
+		if (IS_ERR(handle)) {
+			status = PTR_ERR(handle);
+			mlog_errno(status);
+			goto bail_up;
+		}
+
+		clusters = le32_to_cpu(tl->tl_recs[i].t_clusters);
+		start_cluster = le32_to_cpu(tl->tl_recs[i].t_start);
+		start_blk = ocfs2_clusters_to_blocks(osb->sb, start_cluster);
+
+		status = ocfs2_truncate_log_append(osb, handle,
+						   start_blk, clusters);
+		ocfs2_commit_trans(osb, handle);
+		if (status < 0) {
+			mlog_errno(status);
+			goto bail_up;
+		}
+	}
+
+bail_up:
+	inode_unlock(tl_inode);
+
+	return status;
+}
+
+void ocfs2_truncate_log_shutdown(struct ocfs2_super *osb)
+{
+	int status;
+	struct inode *tl_inode = osb->osb_tl_inode;
+
+	atomic_set(&osb->osb_tl_disable, 1);
+
+	if (tl_inode) {
+		cancel_delayed_work(&osb->osb_truncate_log_wq);
+		flush_workqueue(osb->ocfs2_wq);
+
+		status = ocfs2_flush_truncate_log(osb);
+		if (status < 0)
+			mlog_errno(status);
+
+		brelse(osb->osb_tl_bh);
+		iput(osb->osb_tl_inode);
+	}
+}
+
+int ocfs2_truncate_log_init(struct ocfs2_super *osb)
+{
+	int status;
+	struct inode *tl_inode = NULL;
+	struct buffer_head *tl_bh = NULL;
+
+	status = ocfs2_get_truncate_log_info(osb,
+					     osb->slot_num,
+					     &tl_inode,
+					     &tl_bh);
+	if (status < 0)
+		mlog_errno(status);
+
+	/* ocfs2_truncate_log_shutdown keys on the existence of
+	 * osb->osb_tl_inode so we don't set any of the osb variables
+	 * until we're sure all is well. */
+	INIT_DELAYED_WORK(&osb->osb_truncate_log_wq,
+			  ocfs2_truncate_log_worker);
+	atomic_set(&osb->osb_tl_disable, 0);
+	osb->osb_tl_bh    = tl_bh;
+	osb->osb_tl_inode = tl_inode;
+
+	return status;
+}
+
+/*
+ * Delayed de-allocation of suballocator blocks.
+ *
+ * Some sets of block de-allocations might involve multiple suballocator inodes.
+ *
+ * The locking for this can get extremely complicated, especially when
+ * the suballocator inodes to delete from aren't known until deep
+ * within an unrelated codepath.
+ *
+ * ocfs2_extent_block structures are a good example of this - an inode
+ * btree could have been grown by any number of nodes each allocating
+ * out of their own suballoc inode.
+ *
+ * These structures allow the delay of block de-allocation until a
+ * later time, when locking of multiple cluster inodes won't cause
+ * deadlock.
+ */
+
+/*
+ * Describe a single bit freed from a suballocator.  For the block
+ * suballocators, it represents one block.  For the global cluster
+ * allocator, it represents some clusters and free_bit indicates
+ * clusters number.
+ */
+struct ocfs2_cached_block_free {
+	struct ocfs2_cached_block_free		*free_next;
+	u64					free_bg;
+	u64					free_blk;
+	unsigned int				free_bit;
+};
+
+struct ocfs2_per_slot_free_list {
+	struct ocfs2_per_slot_free_list		*f_next_suballocator;
+	int					f_inode_type;
+	int					f_slot;
+	struct ocfs2_cached_block_free		*f_first;
+};
+
+static int ocfs2_free_cached_blocks(struct ocfs2_super *osb,
+				    int sysfile_type,
+				    int slot,
+				    struct ocfs2_cached_block_free *head)
+{
+	int ret;
+	u64 bg_blkno;
+	handle_t *handle;
+	struct inode *inode;
+	struct buffer_head *di_bh = NULL;
+	struct ocfs2_cached_block_free *tmp;
+
+	inode = ocfs2_get_system_file_inode(osb, sysfile_type, slot);
+	if (!inode) {
+		ret = -EINVAL;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	inode_lock(inode);
+
+	ret = ocfs2_inode_lock(inode, &di_bh, 1);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_mutex;
+	}
+
+	while (head) {
+		if (head->free_bg)
+			bg_blkno = head->free_bg;
+		else
+			bg_blkno = ocfs2_which_suballoc_group(head->free_blk,
+							      head->free_bit);
+		handle = ocfs2_start_trans(osb, OCFS2_SUBALLOC_FREE);
+		if (IS_ERR(handle)) {
+			ret = PTR_ERR(handle);
+			mlog_errno(ret);
+			goto out_unlock;
+		}
+
+		trace_ocfs2_free_cached_blocks(
+		     (unsigned long long)head->free_blk, head->free_bit);
+
+		ret = ocfs2_free_suballoc_bits(handle, inode, di_bh,
+					       head->free_bit, bg_blkno, 1);
+		if (ret)
+			mlog_errno(ret);
+
+		ocfs2_commit_trans(osb, handle);
+
+		tmp = head;
+		head = head->free_next;
+		kfree(tmp);
+	}
+
+out_unlock:
+	ocfs2_inode_unlock(inode, 1);
+	brelse(di_bh);
+out_mutex:
+	inode_unlock(inode);
+	iput(inode);
+out:
+	while(head) {
+		/* Premature exit may have left some dangling items. */
+		tmp = head;
+		head = head->free_next;
+		kfree(tmp);
+	}
+
+	return ret;
+}
+
+int ocfs2_cache_cluster_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
+				u64 blkno, unsigned int bit)
+{
+	int ret = 0;
+	struct ocfs2_cached_block_free *item;
+
+	item = kzalloc(sizeof(*item), GFP_NOFS);
+	if (item == NULL) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		return ret;
+	}
+
+	trace_ocfs2_cache_cluster_dealloc((unsigned long long)blkno, bit);
+
+	item->free_blk = blkno;
+	item->free_bit = bit;
+	item->free_next = ctxt->c_global_allocator;
+
+	ctxt->c_global_allocator = item;
+	return ret;
+}
+
+static int ocfs2_free_cached_clusters(struct ocfs2_super *osb,
+				      struct ocfs2_cached_block_free *head)
+{
+	struct ocfs2_cached_block_free *tmp;
+	struct inode *tl_inode = osb->osb_tl_inode;
+	handle_t *handle;
+	int ret = 0;
+
+	inode_lock(tl_inode);
+
+	while (head) {
+		if (ocfs2_truncate_log_needs_flush(osb)) {
+			ret = __ocfs2_flush_truncate_log(osb);
+			if (ret < 0) {
+				mlog_errno(ret);
+				break;
+			}
+		}
+
+		handle = ocfs2_start_trans(osb, OCFS2_TRUNCATE_LOG_UPDATE);
+		if (IS_ERR(handle)) {
+			ret = PTR_ERR(handle);
+			mlog_errno(ret);
+			break;
+		}
+
+		ret = ocfs2_truncate_log_append(osb, handle, head->free_blk,
+						head->free_bit);
+
+		ocfs2_commit_trans(osb, handle);
+		tmp = head;
+		head = head->free_next;
+		kfree(tmp);
+
+		if (ret < 0) {
+			mlog_errno(ret);
+			break;
+		}
+	}
+
+	inode_unlock(tl_inode);
+
+	while (head) {
+		/* Premature exit may have left some dangling items. */
+		tmp = head;
+		head = head->free_next;
+		kfree(tmp);
+	}
+
+	return ret;
+}
+
+int ocfs2_run_deallocs(struct ocfs2_super *osb,
+		       struct ocfs2_cached_dealloc_ctxt *ctxt)
+{
+	int ret = 0, ret2;
+	struct ocfs2_per_slot_free_list *fl;
+
+	if (!ctxt)
+		return 0;
+
+	while (ctxt->c_first_suballocator) {
+		fl = ctxt->c_first_suballocator;
+
+		if (fl->f_first) {
+			trace_ocfs2_run_deallocs(fl->f_inode_type,
+						 fl->f_slot);
+			ret2 = ocfs2_free_cached_blocks(osb,
+							fl->f_inode_type,
+							fl->f_slot,
+							fl->f_first);
+			if (ret2)
+				mlog_errno(ret2);
+			if (!ret)
+				ret = ret2;
+		}
+
+		ctxt->c_first_suballocator = fl->f_next_suballocator;
+		kfree(fl);
+	}
+
+	if (ctxt->c_global_allocator) {
+		ret2 = ocfs2_free_cached_clusters(osb,
+						  ctxt->c_global_allocator);
+		if (ret2)
+			mlog_errno(ret2);
+		if (!ret)
+			ret = ret2;
+
+		ctxt->c_global_allocator = NULL;
+	}
+
+	return ret;
+}
+
+static struct ocfs2_per_slot_free_list *
+ocfs2_find_per_slot_free_list(int type,
+			      int slot,
+			      struct ocfs2_cached_dealloc_ctxt *ctxt)
+{
+	struct ocfs2_per_slot_free_list *fl = ctxt->c_first_suballocator;
+
+	while (fl) {
+		if (fl->f_inode_type == type && fl->f_slot == slot)
+			return fl;
+
+		fl = fl->f_next_suballocator;
+	}
+
+	fl = kmalloc(sizeof(*fl), GFP_NOFS);
+	if (fl) {
+		fl->f_inode_type = type;
+		fl->f_slot = slot;
+		fl->f_first = NULL;
+		fl->f_next_suballocator = ctxt->c_first_suballocator;
+
+		ctxt->c_first_suballocator = fl;
+	}
+	return fl;
+}
+
+static struct ocfs2_per_slot_free_list *
+ocfs2_find_preferred_free_list(int type,
+			       int preferred_slot,
+			       int *real_slot,
+			       struct ocfs2_cached_dealloc_ctxt *ctxt)
+{
+	struct ocfs2_per_slot_free_list *fl = ctxt->c_first_suballocator;
+
+	while (fl) {
+		if (fl->f_inode_type == type && fl->f_slot == preferred_slot) {
+			*real_slot = fl->f_slot;
+			return fl;
+		}
+
+		fl = fl->f_next_suballocator;
+	}
+
+	/* If we can't find any free list matching preferred slot, just use
+	 * the first one.
+	 */
+	fl = ctxt->c_first_suballocator;
+	*real_slot = fl->f_slot;
+
+	return fl;
+}
+
+/* Return Value 1 indicates empty */
+static int ocfs2_is_dealloc_empty(struct ocfs2_extent_tree *et)
+{
+	struct ocfs2_per_slot_free_list *fl = NULL;
+
+	if (!et->et_dealloc)
+		return 1;
+
+	fl = et->et_dealloc->c_first_suballocator;
+	if (!fl)
+		return 1;
+
+	if (!fl->f_first)
+		return 1;
+
+	return 0;
+}
+
+/* If extent was deleted from tree due to extent rotation and merging, and
+ * no metadata is reserved ahead of time. Try to reuse some extents
+ * just deleted. This is only used to reuse extent blocks.
+ * It is supposed to find enough extent blocks in dealloc if our estimation
+ * on metadata is accurate.
+ */
+static int ocfs2_reuse_blk_from_dealloc(handle_t *handle,
+					struct ocfs2_extent_tree *et,
+					struct buffer_head **new_eb_bh,
+					int blk_wanted, int *blk_given)
+{
+	int i, status = 0, real_slot;
+	struct ocfs2_cached_dealloc_ctxt *dealloc;
+	struct ocfs2_per_slot_free_list *fl;
+	struct ocfs2_cached_block_free *bf;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_super *osb =
+		OCFS2_SB(ocfs2_metadata_cache_get_super(et->et_ci));
+
+	*blk_given = 0;
+
+	/* If extent tree doesn't have a dealloc, this is not faulty. Just
+	 * tell upper caller dealloc can't provide any block and it should
+	 * ask for alloc to claim more space.
+	 */
+	dealloc = et->et_dealloc;
+	if (!dealloc)
+		goto bail;
+
+	for (i = 0; i < blk_wanted; i++) {
+		/* Prefer to use local slot */
+		fl = ocfs2_find_preferred_free_list(EXTENT_ALLOC_SYSTEM_INODE,
+						    osb->slot_num, &real_slot,
+						    dealloc);
+		/* If no more block can be reused, we should claim more
+		 * from alloc. Just return here normally.
+		 */
+		if (!fl) {
+			status = 0;
+			break;
+		}
+
+		bf = fl->f_first;
+		fl->f_first = bf->free_next;
+
+		new_eb_bh[i] = sb_getblk(osb->sb, bf->free_blk);
+		if (new_eb_bh[i] == NULL) {
+			status = -ENOMEM;
+			mlog_errno(status);
+			goto bail;
+		}
+
+		mlog(0, "Reusing block(%llu) from "
+		     "dealloc(local slot:%d, real slot:%d)\n",
+		     bf->free_blk, osb->slot_num, real_slot);
+
+		ocfs2_set_new_buffer_uptodate(et->et_ci, new_eb_bh[i]);
+
+		status = ocfs2_journal_access_eb(handle, et->et_ci,
+						 new_eb_bh[i],
+						 OCFS2_JOURNAL_ACCESS_CREATE);
+		if (status < 0) {
+			mlog_errno(status);
+			goto bail;
+		}
+
+		memset(new_eb_bh[i]->b_data, 0, osb->sb->s_blocksize);
+		eb = (struct ocfs2_extent_block *) new_eb_bh[i]->b_data;
+
+		/* We can't guarantee that buffer head is still cached, so
+		 * polutlate the extent block again.
+		 */
+		strcpy(eb->h_signature, OCFS2_EXTENT_BLOCK_SIGNATURE);
+		eb->h_blkno = cpu_to_le64(bf->free_blk);
+		eb->h_fs_generation = cpu_to_le32(osb->fs_generation);
+		eb->h_suballoc_slot = cpu_to_le16(real_slot);
+		eb->h_suballoc_loc = cpu_to_le64(bf->free_bg);
+		eb->h_suballoc_bit = cpu_to_le16(bf->free_bit);
+		eb->h_list.l_count =
+			cpu_to_le16(ocfs2_extent_recs_per_eb(osb->sb));
+
+		/* We'll also be dirtied by the caller, so
+		 * this isn't absolutely necessary.
+		 */
+		ocfs2_journal_dirty(handle, new_eb_bh[i]);
+
+		if (!fl->f_first) {
+			dealloc->c_first_suballocator = fl->f_next_suballocator;
+			kfree(fl);
+		}
+		kfree(bf);
+	}
+
+	*blk_given = i;
+
+bail:
+	if (unlikely(status < 0)) {
+		for (i = 0; i < blk_wanted; i++)
+			brelse(new_eb_bh[i]);
+	}
+
+	return status;
+}
+
+int ocfs2_cache_block_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
+			      int type, int slot, u64 suballoc,
+			      u64 blkno, unsigned int bit)
+{
+	int ret;
+	struct ocfs2_per_slot_free_list *fl;
+	struct ocfs2_cached_block_free *item;
+
+	fl = ocfs2_find_per_slot_free_list(type, slot, ctxt);
+	if (fl == NULL) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	item = kzalloc(sizeof(*item), GFP_NOFS);
+	if (item == NULL) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	trace_ocfs2_cache_block_dealloc(type, slot,
+					(unsigned long long)suballoc,
+					(unsigned long long)blkno, bit);
+
+	item->free_bg = suballoc;
+	item->free_blk = blkno;
+	item->free_bit = bit;
+	item->free_next = fl->f_first;
+
+	fl->f_first = item;
+
+	ret = 0;
+out:
+	return ret;
+}
+
+static int ocfs2_cache_extent_block_free(struct ocfs2_cached_dealloc_ctxt *ctxt,
+					 struct ocfs2_extent_block *eb)
+{
+	return ocfs2_cache_block_dealloc(ctxt, EXTENT_ALLOC_SYSTEM_INODE,
+					 le16_to_cpu(eb->h_suballoc_slot),
+					 le64_to_cpu(eb->h_suballoc_loc),
+					 le64_to_cpu(eb->h_blkno),
+					 le16_to_cpu(eb->h_suballoc_bit));
+}
+
+static int ocfs2_zero_func(handle_t *handle, struct buffer_head *bh)
+{
+	set_buffer_uptodate(bh);
+	mark_buffer_dirty(bh);
+	return 0;
+}
+
+void ocfs2_map_and_dirty_page(struct inode *inode, handle_t *handle,
+			      unsigned int from, unsigned int to,
+			      struct page *page, int zero, u64 *phys)
+{
+	int ret, partial = 0;
+	loff_t start_byte = ((loff_t)page->index << PAGE_SHIFT) + from;
+	loff_t length = to - from;
+
+	ret = ocfs2_map_page_blocks(page, phys, inode, from, to, 0);
+	if (ret)
+		mlog_errno(ret);
+
+	if (zero)
+		zero_user_segment(page, from, to);
+
+	/*
+	 * Need to set the buffers we zero'd into uptodate
+	 * here if they aren't - ocfs2_map_page_blocks()
+	 * might've skipped some
+	 */
+	ret = walk_page_buffers(handle, page_buffers(page),
+				from, to, &partial,
+				ocfs2_zero_func);
+	if (ret < 0)
+		mlog_errno(ret);
+	else if (ocfs2_should_order_data(inode)) {
+		ret = ocfs2_jbd2_inode_add_write(handle, inode,
+						 start_byte, length);
+		if (ret < 0)
+			mlog_errno(ret);
+	}
+
+	if (!partial)
+		SetPageUptodate(page);
+
+	flush_dcache_page(page);
+}
+
+static void ocfs2_zero_cluster_pages(struct inode *inode, loff_t start,
+				     loff_t end, struct page **pages,
+				     int numpages, u64 phys, handle_t *handle)
+{
+	int i;
+	struct page *page;
+	unsigned int from, to = PAGE_SIZE;
+	struct super_block *sb = inode->i_sb;
+
+	BUG_ON(!ocfs2_sparse_alloc(OCFS2_SB(sb)));
+
+	if (numpages == 0)
+		goto out;
+
+	to = PAGE_SIZE;
+	for(i = 0; i < numpages; i++) {
+		page = pages[i];
+
+		from = start & (PAGE_SIZE - 1);
+		if ((end >> PAGE_SHIFT) == page->index)
+			to = end & (PAGE_SIZE - 1);
+
+		BUG_ON(from > PAGE_SIZE);
+		BUG_ON(to > PAGE_SIZE);
+
+		ocfs2_map_and_dirty_page(inode, handle, from, to, page, 1,
+					 &phys);
+
+		start = (page->index + 1) << PAGE_SHIFT;
+	}
+out:
+	if (pages)
+		ocfs2_unlock_and_free_pages(pages, numpages);
+}
+
+int ocfs2_grab_pages(struct inode *inode, loff_t start, loff_t end,
+		     struct page **pages, int *num)
+{
+	int numpages, ret = 0;
+	struct address_space *mapping = inode->i_mapping;
+	unsigned long index;
+	loff_t last_page_bytes;
+
+	BUG_ON(start > end);
+
+	numpages = 0;
+	last_page_bytes = PAGE_ALIGN(end);
+	index = start >> PAGE_SHIFT;
+	do {
+		pages[numpages] = find_or_create_page(mapping, index, GFP_NOFS);
+		if (!pages[numpages]) {
+			ret = -ENOMEM;
+			mlog_errno(ret);
+			goto out;
+		}
+
+		numpages++;
+		index++;
+	} while (index < (last_page_bytes >> PAGE_SHIFT));
+
+out:
+	if (ret != 0) {
+		if (pages)
+			ocfs2_unlock_and_free_pages(pages, numpages);
+		numpages = 0;
+	}
+
+	*num = numpages;
+
+	return ret;
+}
+
+static int ocfs2_grab_eof_pages(struct inode *inode, loff_t start, loff_t end,
+				struct page **pages, int *num)
+{
+	struct super_block *sb = inode->i_sb;
+
+	BUG_ON(start >> OCFS2_SB(sb)->s_clustersize_bits !=
+	       (end - 1) >> OCFS2_SB(sb)->s_clustersize_bits);
+
+	return ocfs2_grab_pages(inode, start, end, pages, num);
+}
+
+/*
+ * Zero partial cluster for a hole punch or truncate. This avoids exposing
+ * nonzero data on subsequent file extends.
+ *
+ * We need to call this before i_size is updated on the inode because
+ * otherwise block_write_full_page() will skip writeout of pages past
+ * i_size.
+ */
+int ocfs2_zero_range_for_truncate(struct inode *inode, handle_t *handle,
+				  u64 range_start, u64 range_end)
+{
+	int ret = 0, numpages;
+	struct page **pages = NULL;
+	u64 phys;
+	unsigned int ext_flags;
+	struct super_block *sb = inode->i_sb;
+
+	/*
+	 * File systems which don't support sparse files zero on every
+	 * extend.
+	 */
+	if (!ocfs2_sparse_alloc(OCFS2_SB(sb)))
+		return 0;
+
+	/*
+	 * Avoid zeroing pages fully beyond current i_size. It is pointless as
+	 * underlying blocks of those pages should be already zeroed out and
+	 * page writeback will skip them anyway.
+	 */
+	range_end = min_t(u64, range_end, i_size_read(inode));
+	if (range_start >= range_end)
+		return 0;
+
+	pages = kcalloc(ocfs2_pages_per_cluster(sb),
+			sizeof(struct page *), GFP_NOFS);
+	if (pages == NULL) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_extent_map_get_blocks(inode,
+					  range_start >> sb->s_blocksize_bits,
+					  &phys, NULL, &ext_flags);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * Tail is a hole, or is marked unwritten. In either case, we
+	 * can count on read and write to return/push zero's.
+	 */
+	if (phys == 0 || ext_flags & OCFS2_EXT_UNWRITTEN)
+		goto out;
+
+	ret = ocfs2_grab_eof_pages(inode, range_start, range_end, pages,
+				   &numpages);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ocfs2_zero_cluster_pages(inode, range_start, range_end, pages,
+				 numpages, phys, handle);
+
+	/*
+	 * Initiate writeout of the pages we zero'd here. We don't
+	 * wait on them - the truncate_inode_pages() call later will
+	 * do that for us.
+	 */
+	ret = filemap_fdatawrite_range(inode->i_mapping, range_start,
+				       range_end - 1);
+	if (ret)
+		mlog_errno(ret);
+
+out:
+	kfree(pages);
+
+	return ret;
+}
+
+static void ocfs2_zero_dinode_id2_with_xattr(struct inode *inode,
+					     struct ocfs2_dinode *di)
+{
+	unsigned int blocksize = 1 << inode->i_sb->s_blocksize_bits;
+	unsigned int xattrsize = le16_to_cpu(di->i_xattr_inline_size);
+
+	if (le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_XATTR_FL)
+		memset(&di->id2, 0, blocksize -
+				    offsetof(struct ocfs2_dinode, id2) -
+				    xattrsize);
+	else
+		memset(&di->id2, 0, blocksize -
+				    offsetof(struct ocfs2_dinode, id2));
+}
+
+void ocfs2_dinode_new_extent_list(struct inode *inode,
+				  struct ocfs2_dinode *di)
+{
+	ocfs2_zero_dinode_id2_with_xattr(inode, di);
+	di->id2.i_list.l_tree_depth = 0;
+	di->id2.i_list.l_next_free_rec = 0;
+	di->id2.i_list.l_count = cpu_to_le16(
+		ocfs2_extent_recs_per_inode_with_xattr(inode->i_sb, di));
+}
+
+void ocfs2_set_inode_data_inline(struct inode *inode, struct ocfs2_dinode *di)
+{
+	struct ocfs2_inode_info *oi = OCFS2_I(inode);
+	struct ocfs2_inline_data *idata = &di->id2.i_data;
+
+	spin_lock(&oi->ip_lock);
+	oi->ip_dyn_features |= OCFS2_INLINE_DATA_FL;
+	di->i_dyn_features = cpu_to_le16(oi->ip_dyn_features);
+	spin_unlock(&oi->ip_lock);
+
+	/*
+	 * We clear the entire i_data structure here so that all
+	 * fields can be properly initialized.
+	 */
+	ocfs2_zero_dinode_id2_with_xattr(inode, di);
+
+	idata->id_count = cpu_to_le16(
+			ocfs2_max_inline_data_with_xattr(inode->i_sb, di));
+}
+
+int ocfs2_convert_inline_data_to_extents(struct inode *inode,
+					 struct buffer_head *di_bh)
+{
+	int ret, has_data, num_pages = 0;
+	int need_free = 0;
+	u32 bit_off, num;
+	handle_t *handle;
+	u64 block;
+	struct ocfs2_inode_info *oi = OCFS2_I(inode);
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+	struct ocfs2_alloc_context *data_ac = NULL;
+	struct page *page = NULL;
+	struct ocfs2_extent_tree et;
+	int did_quota = 0;
+
+	has_data = i_size_read(inode) ? 1 : 0;
+
+	if (has_data) {
+		ret = ocfs2_reserve_clusters(osb, 1, &data_ac);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+	handle = ocfs2_start_trans(osb,
+				   ocfs2_inline_to_extents_credits(osb->sb));
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
+				      OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	if (has_data) {
+		unsigned int page_end = min_t(unsigned, PAGE_SIZE,
+							osb->s_clustersize);
+		u64 phys;
+
+		ret = dquot_alloc_space_nodirty(inode,
+				       ocfs2_clusters_to_bytes(osb->sb, 1));
+		if (ret)
+			goto out_commit;
+		did_quota = 1;
+
+		data_ac->ac_resv = &oi->ip_la_data_resv;
+
+		ret = ocfs2_claim_clusters(handle, data_ac, 1, &bit_off,
+					   &num);
+		if (ret) {
+			mlog_errno(ret);
+			goto out_commit;
+		}
+
+		/*
+		 * Save two copies, one for insert, and one that can
+		 * be changed by ocfs2_map_and_dirty_page() below.
+		 */
+		block = phys = ocfs2_clusters_to_blocks(inode->i_sb, bit_off);
+
+		ret = ocfs2_grab_eof_pages(inode, 0, page_end, &page,
+					   &num_pages);
+		if (ret) {
+			mlog_errno(ret);
+			need_free = 1;
+			goto out_commit;
+		}
+
+		/*
+		 * This should populate the 1st page for us and mark
+		 * it up to date.
+		 */
+		ret = ocfs2_read_inline_data(inode, page, di_bh);
+		if (ret) {
+			mlog_errno(ret);
+			need_free = 1;
+			goto out_unlock;
+		}
+
+		ocfs2_map_and_dirty_page(inode, handle, 0, page_end, page, 0,
+					 &phys);
+	}
+
+	spin_lock(&oi->ip_lock);
+	oi->ip_dyn_features &= ~OCFS2_INLINE_DATA_FL;
+	di->i_dyn_features = cpu_to_le16(oi->ip_dyn_features);
+	spin_unlock(&oi->ip_lock);
+
+	ocfs2_update_inode_fsync_trans(handle, inode, 1);
+	ocfs2_dinode_new_extent_list(inode, di);
+
+	ocfs2_journal_dirty(handle, di_bh);
+
+	if (has_data) {
+		/*
+		 * An error at this point should be extremely rare. If
+		 * this proves to be false, we could always re-build
+		 * the in-inode data from our pages.
+		 */
+		ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), di_bh);
+		ret = ocfs2_insert_extent(handle, &et, 0, block, 1, 0, NULL);
+		if (ret) {
+			mlog_errno(ret);
+			need_free = 1;
+			goto out_unlock;
+		}
+
+		inode->i_blocks = ocfs2_inode_sector_count(inode);
+	}
+
+out_unlock:
+	if (page)
+		ocfs2_unlock_and_free_pages(&page, num_pages);
+
+out_commit:
+	if (ret < 0 && did_quota)
+		dquot_free_space_nodirty(inode,
+					  ocfs2_clusters_to_bytes(osb->sb, 1));
+
+	if (need_free) {
+		if (data_ac->ac_which == OCFS2_AC_USE_LOCAL)
+			ocfs2_free_local_alloc_bits(osb, handle, data_ac,
+					bit_off, num);
+		else
+			ocfs2_free_clusters(handle,
+					data_ac->ac_inode,
+					data_ac->ac_bh,
+					ocfs2_clusters_to_blocks(osb->sb, bit_off),
+					num);
+	}
+
+	ocfs2_commit_trans(osb, handle);
+
+out:
+	if (data_ac)
+		ocfs2_free_alloc_context(data_ac);
+	return ret;
+}
+
+/*
+ * It is expected, that by the time you call this function,
+ * inode->i_size and fe->i_size have been adjusted.
+ *
+ * WARNING: This will kfree the truncate context
+ */
+int ocfs2_commit_truncate(struct ocfs2_super *osb,
+			  struct inode *inode,
+			  struct buffer_head *di_bh)
+{
+	int status = 0, i, flags = 0;
+	u32 new_highest_cpos, range, trunc_cpos, trunc_len, phys_cpos, coff;
+	u64 blkno = 0;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_extent_rec *rec;
+	struct ocfs2_path *path = NULL;
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+	struct ocfs2_extent_list *root_el = &(di->id2.i_list);
+	u64 refcount_loc = le64_to_cpu(di->i_refcount_loc);
+	struct ocfs2_extent_tree et;
+	struct ocfs2_cached_dealloc_ctxt dealloc;
+	struct ocfs2_refcount_tree *ref_tree = NULL;
+
+	ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), di_bh);
+	ocfs2_init_dealloc_ctxt(&dealloc);
+
+	new_highest_cpos = ocfs2_clusters_for_bytes(osb->sb,
+						     i_size_read(inode));
+
+	path = ocfs2_new_path(di_bh, &di->id2.i_list,
+			      ocfs2_journal_access_di);
+	if (!path) {
+		status = -ENOMEM;
+		mlog_errno(status);
+		goto bail;
+	}
+
+	ocfs2_extent_map_trunc(inode, new_highest_cpos);
+
+start:
+	/*
+	 * Check that we still have allocation to delete.
+	 */
+	if (OCFS2_I(inode)->ip_clusters == 0) {
+		status = 0;
+		goto bail;
+	}
+
+	/*
+	 * Truncate always works against the rightmost tree branch.
+	 */
+	status = ocfs2_find_path(INODE_CACHE(inode), path, UINT_MAX);
+	if (status) {
+		mlog_errno(status);
+		goto bail;
+	}
+
+	trace_ocfs2_commit_truncate(
+		(unsigned long long)OCFS2_I(inode)->ip_blkno,
+		new_highest_cpos,
+		OCFS2_I(inode)->ip_clusters,
+		path->p_tree_depth);
+
+	/*
+	 * By now, el will point to the extent list on the bottom most
+	 * portion of this tree. Only the tail record is considered in
+	 * each pass.
+	 *
+	 * We handle the following cases, in order:
+	 * - empty extent: delete the remaining branch
+	 * - remove the entire record
+	 * - remove a partial record
+	 * - no record needs to be removed (truncate has completed)
+	 */
+	el = path_leaf_el(path);
+	if (le16_to_cpu(el->l_next_free_rec) == 0) {
+		ocfs2_error(inode->i_sb,
+			    "Inode %llu has empty extent block at %llu\n",
+			    (unsigned long long)OCFS2_I(inode)->ip_blkno,
+			    (unsigned long long)path_leaf_bh(path)->b_blocknr);
+		status = -EROFS;
+		goto bail;
+	}
+
+	i = le16_to_cpu(el->l_next_free_rec) - 1;
+	rec = &el->l_recs[i];
+	flags = rec->e_flags;
+	range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
+
+	if (i == 0 && ocfs2_is_empty_extent(rec)) {
+		/*
+		 * Lower levels depend on this never happening, but it's best
+		 * to check it up here before changing the tree.
+		*/
+		if (root_el->l_tree_depth && rec->e_int_clusters == 0) {
+			mlog(ML_ERROR, "Inode %lu has an empty "
+				    "extent record, depth %u\n", inode->i_ino,
+				    le16_to_cpu(root_el->l_tree_depth));
+			status = ocfs2_remove_rightmost_empty_extent(osb,
+					&et, path, &dealloc);
+			if (status) {
+				mlog_errno(status);
+				goto bail;
+			}
+
+			ocfs2_reinit_path(path, 1);
+			goto start;
+		} else {
+			trunc_cpos = le32_to_cpu(rec->e_cpos);
+			trunc_len = 0;
+			blkno = 0;
+		}
+	} else if (le32_to_cpu(rec->e_cpos) >= new_highest_cpos) {
+		/*
+		 * Truncate entire record.
+		 */
+		trunc_cpos = le32_to_cpu(rec->e_cpos);
+		trunc_len = ocfs2_rec_clusters(el, rec);
+		blkno = le64_to_cpu(rec->e_blkno);
+	} else if (range > new_highest_cpos) {
+		/*
+		 * Partial truncate. it also should be
+		 * the last truncate we're doing.
+		 */
+		trunc_cpos = new_highest_cpos;
+		trunc_len = range - new_highest_cpos;
+		coff = new_highest_cpos - le32_to_cpu(rec->e_cpos);
+		blkno = le64_to_cpu(rec->e_blkno) +
+				ocfs2_clusters_to_blocks(inode->i_sb, coff);
+	} else {
+		/*
+		 * Truncate completed, leave happily.
+		 */
+		status = 0;
+		goto bail;
+	}
+
+	phys_cpos = ocfs2_blocks_to_clusters(inode->i_sb, blkno);
+
+	if ((flags & OCFS2_EXT_REFCOUNTED) && trunc_len && !ref_tree) {
+		status = ocfs2_lock_refcount_tree(osb, refcount_loc, 1,
+				&ref_tree, NULL);
+		if (status) {
+			mlog_errno(status);
+			goto bail;
+		}
+	}
+
+	status = ocfs2_remove_btree_range(inode, &et, trunc_cpos,
+					  phys_cpos, trunc_len, flags, &dealloc,
+					  refcount_loc, true);
+	if (status < 0) {
+		mlog_errno(status);
+		goto bail;
+	}
+
+	ocfs2_reinit_path(path, 1);
+
+	/*
+	 * The check above will catch the case where we've truncated
+	 * away all allocation.
+	 */
+	goto start;
+
+bail:
+	if (ref_tree)
+		ocfs2_unlock_refcount_tree(osb, ref_tree, 1);
+
+	ocfs2_schedule_truncate_log_flush(osb, 1);
+
+	ocfs2_run_deallocs(osb, &dealloc);
+
+	ocfs2_free_path(path);
+
+	return status;
+}
+
+/*
+ * 'start' is inclusive, 'end' is not.
+ */
+int ocfs2_truncate_inline(struct inode *inode, struct buffer_head *di_bh,
+			  unsigned int start, unsigned int end, int trunc)
+{
+	int ret;
+	unsigned int numbytes;
+	handle_t *handle;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+	struct ocfs2_inline_data *idata = &di->id2.i_data;
+
+	/* No need to punch hole beyond i_size. */
+	if (start >= i_size_read(inode))
+		return 0;
+
+	if (end > i_size_read(inode))
+		end = i_size_read(inode);
+
+	BUG_ON(start > end);
+
+	if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
+	    !(le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_DATA_FL) ||
+	    !ocfs2_supports_inline_data(osb)) {
+		ocfs2_error(inode->i_sb,
+			    "Inline data flags for inode %llu don't agree! Disk: 0x%x, Memory: 0x%x, Superblock: 0x%x\n",
+			    (unsigned long long)OCFS2_I(inode)->ip_blkno,
+			    le16_to_cpu(di->i_dyn_features),
+			    OCFS2_I(inode)->ip_dyn_features,
+			    osb->s_feature_incompat);
+		ret = -EROFS;
+		goto out;
+	}
+
+	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
+				      OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	numbytes = end - start;
+	memset(idata->id_data + start, 0, numbytes);
+
+	/*
+	 * No need to worry about the data page here - it's been
+	 * truncated already and inline data doesn't need it for
+	 * pushing zero's to disk, so we'll let read_folio pick it up
+	 * later.
+	 */
+	if (trunc) {
+		i_size_write(inode, start);
+		di->i_size = cpu_to_le64(start);
+	}
+
+	inode->i_blocks = ocfs2_inode_sector_count(inode);
+	inode->i_mtime = inode_set_ctime_current(inode);
+
+	di->i_ctime = di->i_mtime = cpu_to_le64(inode_get_ctime(inode).tv_sec);
+	di->i_ctime_nsec = di->i_mtime_nsec = cpu_to_le32(inode_get_ctime(inode).tv_nsec);
+
+	ocfs2_update_inode_fsync_trans(handle, inode, 1);
+	ocfs2_journal_dirty(handle, di_bh);
+
+out_commit:
+	ocfs2_commit_trans(osb, handle);
+
+out:
+	return ret;
+}
+
+static int ocfs2_trim_extent(struct super_block *sb,
+			     struct ocfs2_group_desc *gd,
+			     u64 group, u32 start, u32 count)
+{
+	u64 discard, bcount;
+	struct ocfs2_super *osb = OCFS2_SB(sb);
+
+	bcount = ocfs2_clusters_to_blocks(sb, count);
+	discard = ocfs2_clusters_to_blocks(sb, start);
+
+	/*
+	 * For the first cluster group, the gd->bg_blkno is not at the start
+	 * of the group, but at an offset from the start. If we add it while
+	 * calculating discard for first group, we will wrongly start fstrim a
+	 * few blocks after the desried start block and the range can cross
+	 * over into the next cluster group. So, add it only if this is not
+	 * the first cluster group.
+	 */
+	if (group != osb->first_cluster_group_blkno)
+		discard += le64_to_cpu(gd->bg_blkno);
+
+	trace_ocfs2_trim_extent(sb, (unsigned long long)discard, bcount);
+
+	return sb_issue_discard(sb, discard, bcount, GFP_NOFS, 0);
+}
+
+static int ocfs2_trim_group(struct super_block *sb,
+			    struct ocfs2_group_desc *gd, u64 group,
+			    u32 start, u32 max, u32 minbits)
+{
+	int ret = 0, count = 0, next;
+	void *bitmap = gd->bg_bitmap;
+
+	if (le16_to_cpu(gd->bg_free_bits_count) < minbits)
+		return 0;
+
+	trace_ocfs2_trim_group((unsigned long long)le64_to_cpu(gd->bg_blkno),
+			       start, max, minbits);
+
+	while (start < max) {
+		start = ocfs2_find_next_zero_bit(bitmap, max, start);
+		if (start >= max)
+			break;
+		next = ocfs2_find_next_bit(bitmap, max, start);
+
+		if ((next - start) >= minbits) {
+			ret = ocfs2_trim_extent(sb, gd, group,
+						start, next - start);
+			if (ret < 0) {
+				mlog_errno(ret);
+				break;
+			}
+			count += next - start;
+		}
+		start = next + 1;
+
+		if (fatal_signal_pending(current)) {
+			count = -ERESTARTSYS;
+			break;
+		}
+
+		if ((le16_to_cpu(gd->bg_free_bits_count) - count) < minbits)
+			break;
+	}
+
+	if (ret < 0)
+		count = ret;
+
+	return count;
+}
+
+static
+int ocfs2_trim_mainbm(struct super_block *sb, struct fstrim_range *range)
+{
+	struct ocfs2_super *osb = OCFS2_SB(sb);
+	u64 start, len, trimmed = 0, first_group, last_group = 0, group = 0;
+	int ret, cnt;
+	u32 first_bit, last_bit, minlen;
+	struct buffer_head *main_bm_bh = NULL;
+	struct inode *main_bm_inode = NULL;
+	struct buffer_head *gd_bh = NULL;
+	struct ocfs2_dinode *main_bm;
+	struct ocfs2_group_desc *gd = NULL;
+
+	start = range->start >> osb->s_clustersize_bits;
+	len = range->len >> osb->s_clustersize_bits;
+	minlen = range->minlen >> osb->s_clustersize_bits;
+
+	if (minlen >= osb->bitmap_cpg || range->len < sb->s_blocksize)
+		return -EINVAL;
+
+	trace_ocfs2_trim_mainbm(start, len, minlen);
+
+next_group:
+	main_bm_inode = ocfs2_get_system_file_inode(osb,
+						    GLOBAL_BITMAP_SYSTEM_INODE,
+						    OCFS2_INVALID_SLOT);
+	if (!main_bm_inode) {
+		ret = -EIO;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	inode_lock(main_bm_inode);
+
+	ret = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 0);
+	if (ret < 0) {
+		mlog_errno(ret);
+		goto out_mutex;
+	}
+	main_bm = (struct ocfs2_dinode *)main_bm_bh->b_data;
+
+	/*
+	 * Do some check before trim the first group.
+	 */
+	if (!group) {
+		if (start >= le32_to_cpu(main_bm->i_clusters)) {
+			ret = -EINVAL;
+			goto out_unlock;
+		}
+
+		if (start + len > le32_to_cpu(main_bm->i_clusters))
+			len = le32_to_cpu(main_bm->i_clusters) - start;
+
+		/*
+		 * Determine first and last group to examine based on
+		 * start and len
+		 */
+		first_group = ocfs2_which_cluster_group(main_bm_inode, start);
+		if (first_group == osb->first_cluster_group_blkno)
+			first_bit = start;
+		else
+			first_bit = start - ocfs2_blocks_to_clusters(sb,
+								first_group);
+		last_group = ocfs2_which_cluster_group(main_bm_inode,
+						       start + len - 1);
+		group = first_group;
+	}
+
+	do {
+		if (first_bit + len >= osb->bitmap_cpg)
+			last_bit = osb->bitmap_cpg;
+		else
+			last_bit = first_bit + len;
+
+		ret = ocfs2_read_group_descriptor(main_bm_inode,
+						  main_bm, group,
+						  &gd_bh);
+		if (ret < 0) {
+			mlog_errno(ret);
+			break;
+		}
+
+		gd = (struct ocfs2_group_desc *)gd_bh->b_data;
+		cnt = ocfs2_trim_group(sb, gd, group,
+				       first_bit, last_bit, minlen);
+		brelse(gd_bh);
+		gd_bh = NULL;
+		if (cnt < 0) {
+			ret = cnt;
+			mlog_errno(ret);
+			break;
+		}
+
+		trimmed += cnt;
+		len -= osb->bitmap_cpg - first_bit;
+		first_bit = 0;
+		if (group == osb->first_cluster_group_blkno)
+			group = ocfs2_clusters_to_blocks(sb, osb->bitmap_cpg);
+		else
+			group += ocfs2_clusters_to_blocks(sb, osb->bitmap_cpg);
+	} while (0);
+
+out_unlock:
+	ocfs2_inode_unlock(main_bm_inode, 0);
+	brelse(main_bm_bh);
+	main_bm_bh = NULL;
+out_mutex:
+	inode_unlock(main_bm_inode);
+	iput(main_bm_inode);
+
+	/*
+	 * If all the groups trim are not done or failed, but we should release
+	 * main_bm related locks for avoiding the current IO starve, then go to
+	 * trim the next group
+	 */
+	if (ret >= 0 && group <= last_group) {
+		cond_resched();
+		goto next_group;
+	}
+out:
+	range->len = trimmed * sb->s_blocksize;
+	return ret;
+}
+
+int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
+{
+	int ret;
+	struct ocfs2_super *osb = OCFS2_SB(sb);
+	struct ocfs2_trim_fs_info info, *pinfo = NULL;
+
+	ocfs2_trim_fs_lock_res_init(osb);
+
+	trace_ocfs2_trim_fs(range->start, range->len, range->minlen);
+
+	ret = ocfs2_trim_fs_lock(osb, NULL, 1);
+	if (ret < 0) {
+		if (ret != -EAGAIN) {
+			mlog_errno(ret);
+			ocfs2_trim_fs_lock_res_uninit(osb);
+			return ret;
+		}
+
+		mlog(ML_NOTICE, "Wait for trim on device (%s) to "
+		     "finish, which is running from another node.\n",
+		     osb->dev_str);
+		ret = ocfs2_trim_fs_lock(osb, &info, 0);
+		if (ret < 0) {
+			mlog_errno(ret);
+			ocfs2_trim_fs_lock_res_uninit(osb);
+			return ret;
+		}
+
+		if (info.tf_valid && info.tf_success &&
+		    info.tf_start == range->start &&
+		    info.tf_len == range->len &&
+		    info.tf_minlen == range->minlen) {
+			/* Avoid sending duplicated trim to a shared device */
+			mlog(ML_NOTICE, "The same trim on device (%s) was "
+			     "just done from node (%u), return.\n",
+			     osb->dev_str, info.tf_nodenum);
+			range->len = info.tf_trimlen;
+			goto out;
+		}
+	}
+
+	info.tf_nodenum = osb->node_num;
+	info.tf_start = range->start;
+	info.tf_len = range->len;
+	info.tf_minlen = range->minlen;
+
+	ret = ocfs2_trim_mainbm(sb, range);
+
+	info.tf_trimlen = range->len;
+	info.tf_success = (ret < 0 ? 0 : 1);
+	pinfo = &info;
+out:
+	ocfs2_trim_fs_unlock(osb, pinfo);
+	ocfs2_trim_fs_lock_res_uninit(osb);
+	return ret;
+}