Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / fs / ocfs2 / alloc.c
diff --git a/kernel/fs/ocfs2/alloc.c b/kernel/fs/ocfs2/alloc.c
new file mode 100644 (file)
index 0000000..2d7f76e
--- /dev/null
@@ -0,0 +1,7405 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * alloc.c
+ *
+ * Extent allocs and frees
+ *
+ * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#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 <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 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 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 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 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 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,
+                                    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_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)) {
+               ocfs2_error(sb,
+                           "Extent block #%llu has bad signature %.*s",
+                           (unsigned long long)bh->b_blocknr, 7,
+                           eb->h_signature);
+               return -EINVAL;
+       }
+
+       if (le64_to_cpu(eb->h_blkno) != bh->b_blocknr) {
+               ocfs2_error(sb,
+                           "Extent block #%llu has an invalid h_blkno "
+                           "of %llu",
+                           (unsigned long long)bh->b_blocknr,
+                           (unsigned long long)le64_to_cpu(eb->h_blkno));
+               return -EINVAL;
+       }
+
+       if (le32_to_cpu(eb->h_fs_generation) != OCFS2_SB(sb)->fs_generation) {
+               ocfs2_error(sb,
+                           "Extent block #%llu has an invalid "
+                           "h_fs_generation of #%u",
+                           (unsigned long long)bh->b_blocknr,
+                           le32_to_cpu(eb->h_fs_generation));
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+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_super *osb,
+                          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;
+               }
+               mlog_errno(status);
+       }
+       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;
+       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;
+       }
+
+       status = ocfs2_create_new_meta_bhs(handle, et, new_blocks,
+                                          meta_ac, new_eb_bhs);
+       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;
+       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;
+
+       status = ocfs2_create_new_meta_bhs(handle, et, 1, meta_ac,
+                                          &new_eb_bh);
+       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) {
+                       ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+                                   "Owner %llu has empty "
+                                   "extent list (next_free_rec == 0)",
+                                   (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci));
+                       status = -EIO;
+                       goto bail;
+               }
+               i = le16_to_cpu(el->l_next_free_rec) - 1;
+               blkno = le64_to_cpu(el->l_recs[i].e_blkno);
+               if (!blkno) {
+                       ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+                                   "Owner %llu has extent "
+                                   "list where extent # %d has no physical "
+                                   "block start",
+                                   (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci), i);
+                       status = -EIO;
+                       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);
+
+       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);
+               goto out;
+       }
+
+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.
+ * left_child_el: is the child list pointed to by left_rec
+ * 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_list *left_child_el,
+                                 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], left_el,
+                                     &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 = left_path->p_node[subtree_index].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, left_el, 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)",
+                           (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 (handle->h_buffer_credits < credits)
+               ret = ocfs2_extend_trans(handle,
+                                        credits - handle->h_buffer_credits);
+
+       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 = handle->h_buffer_credits;
+       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,
+                                    int subtree_index, 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;
+
+       /*
+        * In normal tree rotation process, we will never touch the
+        * tree branch above subtree_index and ocfs2_extend_rotate_transaction
+        * doesn't reserve the credits for them either.
+        *
+        * But we do have a special case here which will update the rightmost
+        * records for all the bh in the path.
+        * So we have to allocate extra credits and access them.
+        */
+       ret = ocfs2_extend_trans(handle, subtree_index);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       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_list *el;
+       struct ocfs2_extent_block *eb;
+
+       el = path_leaf_el(left_path);
+
+       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, subtree_index,
+                                               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);
+
+       BUG_ON(!ocfs2_is_empty_extent(&(path_leaf_el(path)->l_recs[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, subtree_root,
+                                                     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;
+       /*
+        * There's two ways we handle this depending on
+        * whether path is the only existing one.
+        */
+       ret = ocfs2_extend_rotate_transaction(handle, 0,
+                                             handle->h_buffer_credits,
+                                             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_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, subtree_index,
+                                               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;
+}
+
+/*
+ * 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 = handle->h_buffer_credits;
+       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 = -EIO;
+                       ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+                                   "Owner %llu has empty extent block at %llu",
+                                   (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,
+                                                     handle->h_buffer_credits,
+                                                     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,
+                                                     handle->h_buffer_credits,
+                                                     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;
+
+               has_empty_extent = 0;
+       } 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) {
+
+                       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) {
+               /*
+                * 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]));
+
+               /* 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;
+               }
+
+               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) {
+                       /*
+                        * 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_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 ret, 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",
+                                   (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci));
+                       ret = -EIO;
+                       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 enum ocfs2_contig_type
+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)
+{
+       int status;
+       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)
+                               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;
+                               ocfs2_error(sb,
+                                           "Extent block #%llu has an "
+                                           "invalid l_next_free_rec of "
+                                           "%d.  It should have "
+                                           "matched the l_count of %d",
+                                           (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));
+                               status = -EINVAL;
+                               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)
+                       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;
+                               ocfs2_error(sb,
+                                           "Extent block #%llu has an "
+                                           "invalid l_next_free_rec of %d",
+                                           (unsigned long long)le64_to_cpu(eb->h_blkno),
+                                           le16_to_cpu(new_el->l_next_free_rec));
+                               status = -EINVAL;
+                               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:
+       return ret;
+}
+
+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 uninitialized_var(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(osb, 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;
+       struct ocfs2_extent_list *rightmost_el;
+
+       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;
+       }
+
+       ctxt.c_contig_type = ocfs2_figure_merge_contig_type(et, path, el,
+                                                           split_index,
+                                                           split_rec);
+
+       /*
+        * 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) {
+               struct ocfs2_extent_block *eb;
+
+               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;
+               }
+
+               eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
+               rightmost_el = &eb->h_list;
+       } else
+               rightmost_el = path_root_el(path);
+
+       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",
+                    (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",
+                    (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.",
+                           (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 wants_rotate = 0, 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) {
+               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,
+                                             handle->h_buffer_credits,
+                                             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);
+               wants_rotate = 1;
+
+               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);
+               goto out;
+       }
+
+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.",
+                                   (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)",
+                                   (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);
+                       goto out;
+               }
+       }
+
+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(osb, 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);
+                       goto out;
+               }
+       }
+
+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_I(inode)->ip_dyn_features &
+                        OCFS2_HAS_REFCOUNT_FL));
+
+               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;
+       }
+
+       mutex_lock(&tl_inode->i_mutex);
+
+       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:
+       mutex_unlock(&tl_inode->i_mutex);
+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(mutex_trylock(&tl_inode->i_mutex));
+
+       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,
+                                        handle_t *handle,
+                                        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;
+
+       di = (struct ocfs2_dinode *) tl_bh->b_data;
+       tl = &di->id2.i_dealloc;
+       i = le16_to_cpu(tl->tl_used) - 1;
+       while (i >= 0) {
+               /* 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) {
+                       mlog_errno(status);
+                       goto bail;
+               }
+
+               tl->tl_used = cpu_to_le16(i);
+
+               ocfs2_journal_dirty(handle, tl_bh);
+
+               /* TODO: Perhaps we can calculate the bulk of the
+                * credits up front rather than extending like
+                * this. */
+               status = ocfs2_extend_trans(handle,
+                                           OCFS2_TRUNCATE_LOG_FLUSH_ONE_REC);
+               if (status < 0) {
+                       mlog_errno(status);
+                       goto bail;
+               }
+
+               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) {
+                               mlog_errno(status);
+                               goto bail;
+                       }
+               }
+               i--;
+       }
+
+       osb->truncated_clusters = 0;
+
+bail:
+       return status;
+}
+
+/* Expects you to already be holding tl_inode->i_mutex */
+int __ocfs2_flush_truncate_log(struct ocfs2_super *osb)
+{
+       int status;
+       unsigned int num_to_flush;
+       handle_t *handle;
+       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;
+
+       BUG_ON(mutex_trylock(&tl_inode->i_mutex));
+
+       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;
+       }
+
+       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;
+       }
+
+       mutex_lock(&data_alloc_inode->i_mutex);
+
+       status = ocfs2_inode_lock(data_alloc_inode, &data_alloc_bh, 1);
+       if (status < 0) {
+               mlog_errno(status);
+               goto out_mutex;
+       }
+
+       handle = ocfs2_start_trans(osb, OCFS2_TRUNCATE_LOG_UPDATE);
+       if (IS_ERR(handle)) {
+               status = PTR_ERR(handle);
+               mlog_errno(status);
+               goto out_unlock;
+       }
+
+       status = ocfs2_replay_truncate_records(osb, handle, data_alloc_inode,
+                                              data_alloc_bh);
+       if (status < 0)
+               mlog_errno(status);
+
+       ocfs2_commit_trans(osb, handle);
+
+out_unlock:
+       brelse(data_alloc_bh);
+       ocfs2_inode_unlock(data_alloc_inode, 1);
+
+out_mutex:
+       mutex_unlock(&data_alloc_inode->i_mutex);
+       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;
+
+       mutex_lock(&tl_inode->i_mutex);
+       status = __ocfs2_flush_truncate_log(osb);
+       mutex_unlock(&tl_inode->i_mutex);
+
+       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(ocfs2_wq, &osb->osb_truncate_log_wq,
+                                  OCFS2_TRUNCATE_LOG_FLUSH_INTERVAL);
+       }
+}
+
+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));
+
+               *tl_copy = kmalloc(tl_bh->b_size, GFP_KERNEL);
+               if (!(*tl_copy)) {
+                       status = -ENOMEM;
+                       mlog_errno(status);
+                       goto bail;
+               }
+
+               /* Assuming the write-out below goes well, this copy
+                * will be passed back to recovery for processing. */
+               memcpy(*tl_copy, tl_bh->b_data, tl_bh->b_size);
+
+               /* 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:
+       if (tl_inode)
+               iput(tl_inode);
+       brelse(tl_bh);
+
+       if (status < 0 && (*tl_copy)) {
+               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);
+
+       mutex_lock(&tl_inode->i_mutex);
+       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:
+       mutex_unlock(&tl_inode->i_mutex);
+
+       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(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;
+       }
+
+       mutex_lock(&inode->i_mutex);
+
+       ret = ocfs2_inode_lock(inode, &di_bh, 1);
+       if (ret) {
+               mlog_errno(ret);
+               goto out_mutex;
+       }
+
+       handle = ocfs2_start_trans(osb, OCFS2_SUBALLOC_FREE);
+       if (IS_ERR(handle)) {
+               ret = PTR_ERR(handle);
+               mlog_errno(ret);
+               goto out_unlock;
+       }
+
+       while (head) {
+               if (head->free_bg)
+                       bg_blkno = head->free_bg;
+               else
+                       bg_blkno = ocfs2_which_suballoc_group(head->free_blk,
+                                                             head->free_bit);
+               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);
+                       goto out_journal;
+               }
+
+               ret = ocfs2_extend_trans(handle, OCFS2_SUBALLOC_FREE);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out_journal;
+               }
+
+               tmp = head;
+               head = head->free_next;
+               kfree(tmp);
+       }
+
+out_journal:
+       ocfs2_commit_trans(osb, handle);
+
+out_unlock:
+       ocfs2_inode_unlock(inode, 1);
+       brelse(di_bh);
+out_mutex:
+       mutex_unlock(&inode->i_mutex);
+       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;
+
+       mutex_lock(&tl_inode->i_mutex);
+
+       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;
+               }
+       }
+
+       mutex_unlock(&tl_inode->i_mutex);
+
+       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;
+}
+
+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;
+
+       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_file_inode(handle, inode);
+               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_CACHE_SIZE;
+       struct super_block *sb = inode->i_sb;
+
+       BUG_ON(!ocfs2_sparse_alloc(OCFS2_SB(sb)));
+
+       if (numpages == 0)
+               goto out;
+
+       to = PAGE_CACHE_SIZE;
+       for(i = 0; i < numpages; i++) {
+               page = pages[i];
+
+               from = start & (PAGE_CACHE_SIZE - 1);
+               if ((end >> PAGE_CACHE_SHIFT) == page->index)
+                       to = end & (PAGE_CACHE_SIZE - 1);
+
+               BUG_ON(from > PAGE_CACHE_SIZE);
+               BUG_ON(to > PAGE_CACHE_SIZE);
+
+               ocfs2_map_and_dirty_page(inode, handle, from, to, page, 1,
+                                        &phys);
+
+               start = (page->index + 1) << PAGE_CACHE_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_CACHE_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_CACHE_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 the area past i_size but still within an allocated
+ * cluster. 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. The new_i_size parameter is passed for this reason.
+ */
+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;
+
+       pages = kcalloc(ocfs2_pages_per_cluster(sb),
+                       sizeof(struct page *), GFP_NOFS);
+       if (pages == NULL) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto out;
+       }
+
+       if (range_start == range_end)
+               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, i, has_data, num_pages = 0;
+       int need_free = 0;
+       u32 bit_off, num;
+       handle_t *handle;
+       u64 uninitialized_var(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 **pages = NULL;
+       loff_t end = osb->s_clustersize;
+       struct ocfs2_extent_tree et;
+       int did_quota = 0;
+
+       has_data = i_size_read(inode) ? 1 : 0;
+
+       if (has_data) {
+               pages = kcalloc(ocfs2_pages_per_cluster(osb->sb),
+                               sizeof(struct page *), GFP_NOFS);
+               if (pages == NULL) {
+                       ret = -ENOMEM;
+                       mlog_errno(ret);
+                       return ret;
+               }
+
+               ret = ocfs2_reserve_clusters(osb, 1, &data_ac);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto free_pages;
+               }
+       }
+
+       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;
+               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 = &OCFS2_I(inode)->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);
+
+               /*
+                * Non sparse file systems zero on extend, so no need
+                * to do that now.
+                */
+               if (!ocfs2_sparse_alloc(osb) &&
+                   PAGE_CACHE_SIZE < osb->s_clustersize)
+                       end = PAGE_CACHE_SIZE;
+
+               ret = ocfs2_grab_eof_pages(inode, 0, end, pages, &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, pages[0], di_bh);
+               if (ret) {
+                       mlog_errno(ret);
+                       need_free = 1;
+                       goto out_unlock;
+               }
+
+               page_end = PAGE_CACHE_SIZE;
+               if (PAGE_CACHE_SIZE > osb->s_clustersize)
+                       page_end = osb->s_clustersize;
+
+               for (i = 0; i < num_pages; i++)
+                       ocfs2_map_and_dirty_page(inode, handle, 0, page_end,
+                                                pages[i], i > 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 (pages)
+               ocfs2_unlock_and_free_pages(pages, 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);
+free_pages:
+       kfree(pages);
+       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) {
+                       ocfs2_error(inode->i_sb, "Inode %lu has an empty "
+                                   "extent record, depth %u\n", inode->i_ino,
+                                   le16_to_cpu(root_el->l_tree_depth));
+                       status = -EROFS;
+                       goto bail;
+               }
+               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;
+
+       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 readpage 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_ctime = inode->i_mtime = CURRENT_TIME;
+
+       di->i_ctime = di->i_mtime = cpu_to_le64(inode->i_ctime.tv_sec);
+       di->i_ctime_nsec = di->i_mtime_nsec = cpu_to_le32(inode->i_ctime.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,
+                            u32 start, u32 count)
+{
+       u64 discard, bcount;
+
+       bcount = ocfs2_clusters_to_blocks(sb, count);
+       discard = le64_to_cpu(gd->bg_blkno) +
+                       ocfs2_clusters_to_blocks(sb, start);
+
+       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,
+                           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,
+                                               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;
+}
+
+int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
+{
+       struct ocfs2_super *osb = OCFS2_SB(sb);
+       u64 start, len, trimmed, first_group, last_group, group;
+       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;
+
+       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;
+       }
+
+       mutex_lock(&main_bm_inode->i_mutex);
+
+       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;
+
+       if (start >= le32_to_cpu(main_bm->i_clusters)) {
+               ret = -EINVAL;
+               goto out_unlock;
+       }
+
+       len = range->len >> osb->s_clustersize_bits;
+       if (start + len > le32_to_cpu(main_bm->i_clusters))
+               len = le32_to_cpu(main_bm->i_clusters) - start;
+
+       trace_ocfs2_trim_fs(start, len, minlen);
+
+       /* 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);
+       last_bit = osb->bitmap_cpg;
+
+       trimmed = 0;
+       for (group = first_group; group <= last_group;) {
+               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, 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);
+       }
+       range->len = trimmed * sb->s_blocksize;
+out_unlock:
+       ocfs2_inode_unlock(main_bm_inode, 0);
+       brelse(main_bm_bh);
+out_mutex:
+       mutex_unlock(&main_bm_inode->i_mutex);
+       iput(main_bm_inode);
+out:
+       return ret;
+}