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 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * alloc.c
  *
  * Extent allocs and frees
  *
  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
  */
 
 #include <linux/fs.h>
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/highmem.h>
 #include <linux/swap.h>
 #include <linux/quotaops.h>
 #include <linux/blkdev.h>
 #include <linux/sched/signal.h>
 
 #include <cluster/masklog.h>
 
 #include "ocfs2.h"
 
 #include "alloc.h"
 #include "aops.h"
 #include "blockcheck.h"
 #include "dlmglue.h"
 #include "extent_map.h"
 #include "inode.h"
 #include "journal.h"
 #include "localalloc.h"
 #include "suballoc.h"
 #include "sysfile.h"
 #include "file.h"
 #include "super.h"
 #include "uptodate.h"
 #include "xattr.h"
 #include "refcounttree.h"
 #include "ocfs2_trace.h"
 
 #include "buffer_head_io.h"
 
 enum ocfs2_contig_type {
     CONTIG_NONE = 0,
     CONTIG_LEFT,
     CONTIG_RIGHT,
     CONTIG_LEFTRIGHT,
 };
 
 static enum ocfs2_contig_type
     ocfs2_extent_rec_contig(struct super_block *sb,
                 struct ocfs2_extent_rec *ext,
                 struct ocfs2_extent_rec *insert_rec);
 /*
  * Operations for a specific extent tree type.
  *
  * To implement an on-disk btree (extent tree) type in ocfs2, add
  * an ocfs2_extent_tree_operations structure and the matching
  * ocfs2_init_<thingy>_extent_tree() function.  That's pretty much it
  * for the allocation portion of the extent tree.
  */
 struct ocfs2_extent_tree_operations {
     /*
      * last_eb_blk is the block number of the right most leaf extent
      * block.  Most on-disk structures containing an extent tree store
      * this value for fast access.  The ->eo_set_last_eb_blk() and
      * ->eo_get_last_eb_blk() operations access this value.  They are
      *  both required.
      */
     void (*eo_set_last_eb_blk)(struct ocfs2_extent_tree *et,
                    u64 blkno);
     u64 (*eo_get_last_eb_blk)(struct ocfs2_extent_tree *et);
 
     /*
      * The on-disk structure usually keeps track of how many total
      * clusters are stored in this extent tree.  This function updates
      * that value.  new_clusters is the delta, and must be
      * added to the total.  Required.
      */
     void (*eo_update_clusters)(struct ocfs2_extent_tree *et,
                    u32 new_clusters);
 
     /*
      * If this extent tree is supported by an extent map, insert
      * a record into the map.
      */
     void (*eo_extent_map_insert)(struct ocfs2_extent_tree *et,
                      struct ocfs2_extent_rec *rec);
 
     /*
      * If this extent tree is supported by an extent map, truncate the
      * map to clusters,
      */
     void (*eo_extent_map_truncate)(struct ocfs2_extent_tree *et,
                        u32 clusters);
 
     /*
      * If ->eo_insert_check() exists, it is called before rec is
      * inserted into the extent tree.  It is optional.
      */
     int (*eo_insert_check)(struct ocfs2_extent_tree *et,
                    struct ocfs2_extent_rec *rec);
     int (*eo_sanity_check)(struct ocfs2_extent_tree *et);
 
     /*
      * --------------------------------------------------------------
      * The remaining are internal to ocfs2_extent_tree and don't have
      * accessor functions
      */
 
     /*
      * ->eo_fill_root_el() takes et->et_object and sets et->et_root_el.
      * It is required.
      */
     void (*eo_fill_root_el)(struct ocfs2_extent_tree *et);
 
     /*
      * ->eo_fill_max_leaf_clusters sets et->et_max_leaf_clusters if
      * it exists.  If it does not, et->et_max_leaf_clusters is set
      * to 0 (unlimited).  Optional.
      */
     void (*eo_fill_max_leaf_clusters)(struct ocfs2_extent_tree *et);
 
     /*
      * ->eo_extent_contig test whether the 2 ocfs2_extent_rec
      * are contiguous or not. Optional. Don't need to set it if use
      * ocfs2_extent_rec as the tree leaf.
      */
     enum ocfs2_contig_type
         (*eo_extent_contig)(struct ocfs2_extent_tree *et,
                     struct ocfs2_extent_rec *ext,
                     struct ocfs2_extent_rec *insert_rec);
 };
 
 
 /*
  * Pre-declare ocfs2_dinode_et_ops so we can use it as a sanity check
  * in the methods.
  */
 static u64 ocfs2_dinode_get_last_eb_blk(struct ocfs2_extent_tree *et);
 static void ocfs2_dinode_set_last_eb_blk(struct ocfs2_extent_tree *et,
                      u64 blkno);
 static void ocfs2_dinode_update_clusters(struct ocfs2_extent_tree *et,
                      u32 clusters);
 static void ocfs2_dinode_extent_map_insert(struct ocfs2_extent_tree *et,
                        struct ocfs2_extent_rec *rec);
 static void ocfs2_dinode_extent_map_truncate(struct ocfs2_extent_tree *et,
                          u32 clusters);
 static int ocfs2_dinode_insert_check(struct ocfs2_extent_tree *et,
                      struct ocfs2_extent_rec *rec);
 static int ocfs2_dinode_sanity_check(struct ocfs2_extent_tree *et);
 static void ocfs2_dinode_fill_root_el(struct ocfs2_extent_tree *et);
 
 static int ocfs2_reuse_blk_from_dealloc(handle_t *handle,
                     struct ocfs2_extent_tree *et,
                     struct buffer_head **new_eb_bh,
                     int blk_wanted, int *blk_given);
 static int ocfs2_is_dealloc_empty(struct ocfs2_extent_tree *et);
 
 static const struct ocfs2_extent_tree_operations ocfs2_dinode_et_ops = {
     .eo_set_last_eb_blk = ocfs2_dinode_set_last_eb_blk,
     .eo_get_last_eb_blk = ocfs2_dinode_get_last_eb_blk,
     .eo_update_clusters = ocfs2_dinode_update_clusters,
     .eo_extent_map_insert   = ocfs2_dinode_extent_map_insert,
     .eo_extent_map_truncate = ocfs2_dinode_extent_map_truncate,
     .eo_insert_check    = ocfs2_dinode_insert_check,
     .eo_sanity_check    = ocfs2_dinode_sanity_check,
     .eo_fill_root_el    = ocfs2_dinode_fill_root_el,
 };
 
 static void ocfs2_dinode_set_last_eb_blk(struct ocfs2_extent_tree *et,
                      u64 blkno)
 {
     struct ocfs2_dinode *di = et->et_object;
 
     BUG_ON(et->et_ops != &ocfs2_dinode_et_ops);
     di->i_last_eb_blk = cpu_to_le64(blkno);
 }
 
 static u64 ocfs2_dinode_get_last_eb_blk(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_dinode *di = et->et_object;
 
     BUG_ON(et->et_ops != &ocfs2_dinode_et_ops);
     return le64_to_cpu(di->i_last_eb_blk);
 }
 
 static void ocfs2_dinode_update_clusters(struct ocfs2_extent_tree *et,
                      u32 clusters)
 {
     struct ocfs2_inode_info *oi = cache_info_to_inode(et->et_ci);
     struct ocfs2_dinode *di = et->et_object;
 
     le32_add_cpu(&di->i_clusters, clusters);
     spin_lock(&oi->ip_lock);
     oi->ip_clusters = le32_to_cpu(di->i_clusters);
     spin_unlock(&oi->ip_lock);
 }
 
 static void ocfs2_dinode_extent_map_insert(struct ocfs2_extent_tree *et,
                        struct ocfs2_extent_rec *rec)
 {
     struct inode *inode = &cache_info_to_inode(et->et_ci)->vfs_inode;
 
     ocfs2_extent_map_insert_rec(inode, rec);
 }
 
 static void ocfs2_dinode_extent_map_truncate(struct ocfs2_extent_tree *et,
                          u32 clusters)
 {
     struct inode *inode = &cache_info_to_inode(et->et_ci)->vfs_inode;
 
     ocfs2_extent_map_trunc(inode, clusters);
 }
 
 static int ocfs2_dinode_insert_check(struct ocfs2_extent_tree *et,
                      struct ocfs2_extent_rec *rec)
 {
     struct ocfs2_inode_info *oi = cache_info_to_inode(et->et_ci);
     struct ocfs2_super *osb = OCFS2_SB(oi->vfs_inode.i_sb);
 
     BUG_ON(oi->ip_dyn_features & OCFS2_INLINE_DATA_FL);
     mlog_bug_on_msg(!ocfs2_sparse_alloc(osb) &&
             (oi->ip_clusters != le32_to_cpu(rec->e_cpos)),
             "Device %s, asking for sparse allocation: inode %llu, "
             "cpos %u, clusters %u\n",
             osb->dev_str,
             (unsigned long long)oi->ip_blkno,
             rec->e_cpos, oi->ip_clusters);
 
     return 0;
 }
 
 static int ocfs2_dinode_sanity_check(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_dinode *di = et->et_object;
 
     BUG_ON(et->et_ops != &ocfs2_dinode_et_ops);
     BUG_ON(!OCFS2_IS_VALID_DINODE(di));
 
     return 0;
 }
 
 static void ocfs2_dinode_fill_root_el(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_dinode *di = et->et_object;
 
     et->et_root_el = &di->id2.i_list;
 }
 
 
 static void ocfs2_xattr_value_fill_root_el(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_xattr_value_buf *vb = et->et_object;
 
     et->et_root_el = &vb->vb_xv->xr_list;
 }
 
 static void ocfs2_xattr_value_set_last_eb_blk(struct ocfs2_extent_tree *et,
                           u64 blkno)
 {
     struct ocfs2_xattr_value_buf *vb = et->et_object;
 
     vb->vb_xv->xr_last_eb_blk = cpu_to_le64(blkno);
 }
 
 static u64 ocfs2_xattr_value_get_last_eb_blk(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_xattr_value_buf *vb = et->et_object;
 
     return le64_to_cpu(vb->vb_xv->xr_last_eb_blk);
 }
 
 static void ocfs2_xattr_value_update_clusters(struct ocfs2_extent_tree *et,
                           u32 clusters)
 {
     struct ocfs2_xattr_value_buf *vb = et->et_object;
 
     le32_add_cpu(&vb->vb_xv->xr_clusters, clusters);
 }
 
 static const struct ocfs2_extent_tree_operations ocfs2_xattr_value_et_ops = {
     .eo_set_last_eb_blk = ocfs2_xattr_value_set_last_eb_blk,
     .eo_get_last_eb_blk = ocfs2_xattr_value_get_last_eb_blk,
     .eo_update_clusters = ocfs2_xattr_value_update_clusters,
     .eo_fill_root_el    = ocfs2_xattr_value_fill_root_el,
 };
 
 static void ocfs2_xattr_tree_fill_root_el(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_xattr_block *xb = et->et_object;
 
     et->et_root_el = &xb->xb_attrs.xb_root.xt_list;
 }
 
 static void ocfs2_xattr_tree_fill_max_leaf_clusters(struct ocfs2_extent_tree *et)
 {
     struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
     et->et_max_leaf_clusters =
         ocfs2_clusters_for_bytes(sb, OCFS2_MAX_XATTR_TREE_LEAF_SIZE);
 }
 
 static void ocfs2_xattr_tree_set_last_eb_blk(struct ocfs2_extent_tree *et,
                          u64 blkno)
 {
     struct ocfs2_xattr_block *xb = et->et_object;
     struct ocfs2_xattr_tree_root *xt = &xb->xb_attrs.xb_root;
 
     xt->xt_last_eb_blk = cpu_to_le64(blkno);
 }
 
 static u64 ocfs2_xattr_tree_get_last_eb_blk(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_xattr_block *xb = et->et_object;
     struct ocfs2_xattr_tree_root *xt = &xb->xb_attrs.xb_root;
 
     return le64_to_cpu(xt->xt_last_eb_blk);
 }
 
 static void ocfs2_xattr_tree_update_clusters(struct ocfs2_extent_tree *et,
                          u32 clusters)
 {
     struct ocfs2_xattr_block *xb = et->et_object;
 
     le32_add_cpu(&xb->xb_attrs.xb_root.xt_clusters, clusters);
 }
 
 static const struct ocfs2_extent_tree_operations ocfs2_xattr_tree_et_ops = {
     .eo_set_last_eb_blk = ocfs2_xattr_tree_set_last_eb_blk,
     .eo_get_last_eb_blk = ocfs2_xattr_tree_get_last_eb_blk,
     .eo_update_clusters = ocfs2_xattr_tree_update_clusters,
     .eo_fill_root_el    = ocfs2_xattr_tree_fill_root_el,
     .eo_fill_max_leaf_clusters = ocfs2_xattr_tree_fill_max_leaf_clusters,
 };
 
 static void ocfs2_dx_root_set_last_eb_blk(struct ocfs2_extent_tree *et,
                       u64 blkno)
 {
     struct ocfs2_dx_root_block *dx_root = et->et_object;
 
     dx_root->dr_last_eb_blk = cpu_to_le64(blkno);
 }
 
 static u64 ocfs2_dx_root_get_last_eb_blk(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_dx_root_block *dx_root = et->et_object;
 
     return le64_to_cpu(dx_root->dr_last_eb_blk);
 }
 
 static void ocfs2_dx_root_update_clusters(struct ocfs2_extent_tree *et,
                       u32 clusters)
 {
     struct ocfs2_dx_root_block *dx_root = et->et_object;
 
     le32_add_cpu(&dx_root->dr_clusters, clusters);
 }
 
 static int ocfs2_dx_root_sanity_check(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_dx_root_block *dx_root = et->et_object;
 
     BUG_ON(!OCFS2_IS_VALID_DX_ROOT(dx_root));
 
     return 0;
 }
 
 static void ocfs2_dx_root_fill_root_el(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_dx_root_block *dx_root = et->et_object;
 
     et->et_root_el = &dx_root->dr_list;
 }
 
 static const struct ocfs2_extent_tree_operations ocfs2_dx_root_et_ops = {
     .eo_set_last_eb_blk = ocfs2_dx_root_set_last_eb_blk,
     .eo_get_last_eb_blk = ocfs2_dx_root_get_last_eb_blk,
     .eo_update_clusters = ocfs2_dx_root_update_clusters,
     .eo_sanity_check    = ocfs2_dx_root_sanity_check,
     .eo_fill_root_el    = ocfs2_dx_root_fill_root_el,
 };
 
 static void ocfs2_refcount_tree_fill_root_el(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_refcount_block *rb = et->et_object;
 
     et->et_root_el = &rb->rf_list;
 }
 
 static void ocfs2_refcount_tree_set_last_eb_blk(struct ocfs2_extent_tree *et,
                         u64 blkno)
 {
     struct ocfs2_refcount_block *rb = et->et_object;
 
     rb->rf_last_eb_blk = cpu_to_le64(blkno);
 }
 
 static u64 ocfs2_refcount_tree_get_last_eb_blk(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_refcount_block *rb = et->et_object;
 
     return le64_to_cpu(rb->rf_last_eb_blk);
 }
 
 static void ocfs2_refcount_tree_update_clusters(struct ocfs2_extent_tree *et,
                         u32 clusters)
 {
     struct ocfs2_refcount_block *rb = et->et_object;
 
     le32_add_cpu(&rb->rf_clusters, clusters);
 }
 
 static enum ocfs2_contig_type
 ocfs2_refcount_tree_extent_contig(struct ocfs2_extent_tree *et,
                   struct ocfs2_extent_rec *ext,
                   struct ocfs2_extent_rec *insert_rec)
 {
     return CONTIG_NONE;
 }
 
 static const struct ocfs2_extent_tree_operations ocfs2_refcount_tree_et_ops = {
     .eo_set_last_eb_blk = ocfs2_refcount_tree_set_last_eb_blk,
     .eo_get_last_eb_blk = ocfs2_refcount_tree_get_last_eb_blk,
     .eo_update_clusters = ocfs2_refcount_tree_update_clusters,
     .eo_fill_root_el    = ocfs2_refcount_tree_fill_root_el,
     .eo_extent_contig   = ocfs2_refcount_tree_extent_contig,
 };
 
 static void __ocfs2_init_extent_tree(struct ocfs2_extent_tree *et,
                      struct ocfs2_caching_info *ci,
                      struct buffer_head *bh,
                      ocfs2_journal_access_func access,
                      void *obj,
                      const struct ocfs2_extent_tree_operations *ops)
 {
     et->et_ops = ops;
     et->et_root_bh = bh;
     et->et_ci = ci;
     et->et_root_journal_access = access;
     if (!obj)
         obj = (void *)bh->b_data;
     et->et_object = obj;
     et->et_dealloc = NULL;
 
     et->et_ops->eo_fill_root_el(et);
     if (!et->et_ops->eo_fill_max_leaf_clusters)
         et->et_max_leaf_clusters = 0;
     else
         et->et_ops->eo_fill_max_leaf_clusters(et);
 }
 
 void ocfs2_init_dinode_extent_tree(struct ocfs2_extent_tree *et,
                    struct ocfs2_caching_info *ci,
                    struct buffer_head *bh)
 {
     __ocfs2_init_extent_tree(et, ci, bh, ocfs2_journal_access_di,
                  NULL, &ocfs2_dinode_et_ops);
 }
 
 void ocfs2_init_xattr_tree_extent_tree(struct ocfs2_extent_tree *et,
                        struct ocfs2_caching_info *ci,
                        struct buffer_head *bh)
 {
     __ocfs2_init_extent_tree(et, ci, bh, ocfs2_journal_access_xb,
                  NULL, &ocfs2_xattr_tree_et_ops);
 }
 
 void ocfs2_init_xattr_value_extent_tree(struct ocfs2_extent_tree *et,
                     struct ocfs2_caching_info *ci,
                     struct ocfs2_xattr_value_buf *vb)
 {
     __ocfs2_init_extent_tree(et, ci, vb->vb_bh, vb->vb_access, vb,
                  &ocfs2_xattr_value_et_ops);
 }
 
 void ocfs2_init_dx_root_extent_tree(struct ocfs2_extent_tree *et,
                     struct ocfs2_caching_info *ci,
                     struct buffer_head *bh)
 {
     __ocfs2_init_extent_tree(et, ci, bh, ocfs2_journal_access_dr,
                  NULL, &ocfs2_dx_root_et_ops);
 }
 
 void ocfs2_init_refcount_extent_tree(struct ocfs2_extent_tree *et,
                      struct ocfs2_caching_info *ci,
                      struct buffer_head *bh)
 {
     __ocfs2_init_extent_tree(et, ci, bh, ocfs2_journal_access_rb,
                  NULL, &ocfs2_refcount_tree_et_ops);
 }
 
 static inline void ocfs2_et_set_last_eb_blk(struct ocfs2_extent_tree *et,
                         u64 new_last_eb_blk)
 {
     et->et_ops->eo_set_last_eb_blk(et, new_last_eb_blk);
 }
 
 static inline u64 ocfs2_et_get_last_eb_blk(struct ocfs2_extent_tree *et)
 {
     return et->et_ops->eo_get_last_eb_blk(et);
 }
 
 static inline void ocfs2_et_update_clusters(struct ocfs2_extent_tree *et,
                         u32 clusters)
 {
     et->et_ops->eo_update_clusters(et, clusters);
 }
 
 static inline void ocfs2_et_extent_map_insert(struct ocfs2_extent_tree *et,
                           struct ocfs2_extent_rec *rec)
 {
     if (et->et_ops->eo_extent_map_insert)
         et->et_ops->eo_extent_map_insert(et, rec);
 }
 
 static inline void ocfs2_et_extent_map_truncate(struct ocfs2_extent_tree *et,
                         u32 clusters)
 {
     if (et->et_ops->eo_extent_map_truncate)
         et->et_ops->eo_extent_map_truncate(et, clusters);
 }
 
 static inline int ocfs2_et_root_journal_access(handle_t *handle,
                            struct ocfs2_extent_tree *et,
                            int type)
 {
     return et->et_root_journal_access(handle, et->et_ci, et->et_root_bh,
                       type);
 }
 
 static inline enum ocfs2_contig_type
     ocfs2_et_extent_contig(struct ocfs2_extent_tree *et,
                    struct ocfs2_extent_rec *rec,
                    struct ocfs2_extent_rec *insert_rec)
 {
     if (et->et_ops->eo_extent_contig)
         return et->et_ops->eo_extent_contig(et, rec, insert_rec);
 
     return ocfs2_extent_rec_contig(
                 ocfs2_metadata_cache_get_super(et->et_ci),
                 rec, insert_rec);
 }
 
 static inline int ocfs2_et_insert_check(struct ocfs2_extent_tree *et,
                     struct ocfs2_extent_rec *rec)
 {
     int ret = 0;
 
     if (et->et_ops->eo_insert_check)
         ret = et->et_ops->eo_insert_check(et, rec);
     return ret;
 }
 
 static inline int ocfs2_et_sanity_check(struct ocfs2_extent_tree *et)
 {
     int ret = 0;
 
     if (et->et_ops->eo_sanity_check)
         ret = et->et_ops->eo_sanity_check(et);
     return ret;
 }
 
 static int ocfs2_cache_extent_block_free(struct ocfs2_cached_dealloc_ctxt *ctxt,
                      struct ocfs2_extent_block *eb);
 static void ocfs2_adjust_rightmost_records(handle_t *handle,
                        struct ocfs2_extent_tree *et,
                        struct ocfs2_path *path,
                        struct ocfs2_extent_rec *insert_rec);
 /*
  * Reset the actual path elements so that we can re-use the structure
  * to build another path. Generally, this involves freeing the buffer
  * heads.
  */
 void ocfs2_reinit_path(struct ocfs2_path *path, int keep_root)
 {
     int i, start = 0, depth = 0;
     struct ocfs2_path_item *node;
 
     if (keep_root)
         start = 1;
 
     for(i = start; i < path_num_items(path); i++) {
         node = &path->p_node[i];
 
         brelse(node->bh);
         node->bh = NULL;
         node->el = NULL;
     }
 
     /*
      * Tree depth may change during truncate, or insert. If we're
      * keeping the root extent list, then make sure that our path
      * structure reflects the proper depth.
      */
     if (keep_root)
         depth = le16_to_cpu(path_root_el(path)->l_tree_depth);
     else
         path_root_access(path) = NULL;
 
     path->p_tree_depth = depth;
 }
 
 void ocfs2_free_path(struct ocfs2_path *path)
 {
     if (path) {
         ocfs2_reinit_path(path, 0);
         kfree(path);
     }
 }
 
 /*
  * All the elements of src into dest. After this call, src could be freed
  * without affecting dest.
  *
  * Both paths should have the same root. Any non-root elements of dest
  * will be freed.
  */
 static void ocfs2_cp_path(struct ocfs2_path *dest, struct ocfs2_path *src)
 {
     int i;
 
     BUG_ON(path_root_bh(dest) != path_root_bh(src));
     BUG_ON(path_root_el(dest) != path_root_el(src));
     BUG_ON(path_root_access(dest) != path_root_access(src));
 
     ocfs2_reinit_path(dest, 1);
 
     for(i = 1; i < OCFS2_MAX_PATH_DEPTH; i++) {
         dest->p_node[i].bh = src->p_node[i].bh;
         dest->p_node[i].el = src->p_node[i].el;
 
         if (dest->p_node[i].bh)
             get_bh(dest->p_node[i].bh);
     }
 }
 
 /*
  * Make the *dest path the same as src and re-initialize src path to
  * have a root only.
  */
 static void ocfs2_mv_path(struct ocfs2_path *dest, struct ocfs2_path *src)
 {
     int i;
 
     BUG_ON(path_root_bh(dest) != path_root_bh(src));
     BUG_ON(path_root_access(dest) != path_root_access(src));
 
     for(i = 1; i < OCFS2_MAX_PATH_DEPTH; i++) {
         brelse(dest->p_node[i].bh);
 
         dest->p_node[i].bh = src->p_node[i].bh;
         dest->p_node[i].el = src->p_node[i].el;
 
         src->p_node[i].bh = NULL;
         src->p_node[i].el = NULL;
     }
 }
 
 /*
  * Insert an extent block at given index.
  *
  * This will not take an additional reference on eb_bh.
  */
 static inline void ocfs2_path_insert_eb(struct ocfs2_path *path, int index,
                     struct buffer_head *eb_bh)
 {
     struct ocfs2_extent_block *eb = (struct ocfs2_extent_block *)eb_bh->b_data;
 
     /*
      * Right now, no root bh is an extent block, so this helps
      * catch code errors with dinode trees. The assertion can be
      * safely removed if we ever need to insert extent block
      * structures at the root.
      */
     BUG_ON(index == 0);
 
     path->p_node[index].bh = eb_bh;
     path->p_node[index].el = &eb->h_list;
 }
 
 static struct ocfs2_path *ocfs2_new_path(struct buffer_head *root_bh,
                      struct ocfs2_extent_list *root_el,
                      ocfs2_journal_access_func access)
 {
     struct ocfs2_path *path;
 
     BUG_ON(le16_to_cpu(root_el->l_tree_depth) >= OCFS2_MAX_PATH_DEPTH);
 
     path = kzalloc(sizeof(*path), GFP_NOFS);
     if (path) {
         path->p_tree_depth = le16_to_cpu(root_el->l_tree_depth);
         get_bh(root_bh);
         path_root_bh(path) = root_bh;
         path_root_el(path) = root_el;
         path_root_access(path) = access;
     }
 
     return path;
 }
 
 struct ocfs2_path *ocfs2_new_path_from_path(struct ocfs2_path *path)
 {
     return ocfs2_new_path(path_root_bh(path), path_root_el(path),
                   path_root_access(path));
 }
 
 struct ocfs2_path *ocfs2_new_path_from_et(struct ocfs2_extent_tree *et)
 {
     return ocfs2_new_path(et->et_root_bh, et->et_root_el,
                   et->et_root_journal_access);
 }
 
 /*
  * Journal the buffer at depth idx.  All idx>0 are extent_blocks,
  * otherwise it's the root_access function.
  *
  * I don't like the way this function's name looks next to
  * ocfs2_journal_access_path(), but I don't have a better one.
  */
 int ocfs2_path_bh_journal_access(handle_t *handle,
                  struct ocfs2_caching_info *ci,
                  struct ocfs2_path *path,
                  int idx)
 {
     ocfs2_journal_access_func access = path_root_access(path);
 
     if (!access)
         access = ocfs2_journal_access;
 
     if (idx)
         access = ocfs2_journal_access_eb;
 
     return access(handle, ci, path->p_node[idx].bh,
               OCFS2_JOURNAL_ACCESS_WRITE);
 }
 
 /*
  * Convenience function to journal all components in a path.
  */
 int ocfs2_journal_access_path(struct ocfs2_caching_info *ci,
                   handle_t *handle,
                   struct ocfs2_path *path)
 {
     int i, ret = 0;
 
     if (!path)
         goto out;
 
     for(i = 0; i < path_num_items(path); i++) {
         ret = ocfs2_path_bh_journal_access(handle, ci, path, i);
         if (ret < 0) {
             mlog_errno(ret);
             goto out;
         }
     }
 
 out:
     return ret;
 }
 
 /*
  * Return the index of the extent record which contains cluster #v_cluster.
  * -1 is returned if it was not found.
  *
  * Should work fine on interior and exterior nodes.
  */
 int ocfs2_search_extent_list(struct ocfs2_extent_list *el, u32 v_cluster)
 {
     int ret = -1;
     int i;
     struct ocfs2_extent_rec *rec;
     u32 rec_end, rec_start, clusters;
 
     for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
         rec = &el->l_recs[i];
 
         rec_start = le32_to_cpu(rec->e_cpos);
         clusters = ocfs2_rec_clusters(el, rec);
 
         rec_end = rec_start + clusters;
 
         if (v_cluster >= rec_start && v_cluster < rec_end) {
             ret = i;
             break;
         }
     }
 
     return ret;
 }
 
 /*
  * NOTE: ocfs2_block_extent_contig(), ocfs2_extents_adjacent() and
  * ocfs2_extent_rec_contig only work properly against leaf nodes!
  */
 static int ocfs2_block_extent_contig(struct super_block *sb,
                      struct ocfs2_extent_rec *ext,
                      u64 blkno)
 {
     u64 blk_end = le64_to_cpu(ext->e_blkno);
 
     blk_end += ocfs2_clusters_to_blocks(sb,
                     le16_to_cpu(ext->e_leaf_clusters));
 
     return blkno == blk_end;
 }
 
 static int ocfs2_extents_adjacent(struct ocfs2_extent_rec *left,
                   struct ocfs2_extent_rec *right)
 {
     u32 left_range;
 
     left_range = le32_to_cpu(left->e_cpos) +
         le16_to_cpu(left->e_leaf_clusters);
 
     return (left_range == le32_to_cpu(right->e_cpos));
 }
 
 static enum ocfs2_contig_type
     ocfs2_extent_rec_contig(struct super_block *sb,
                 struct ocfs2_extent_rec *ext,
                 struct ocfs2_extent_rec *insert_rec)
 {
     u64 blkno = le64_to_cpu(insert_rec->e_blkno);
 
     /*
      * Refuse to coalesce extent records with different flag
      * fields - we don't want to mix unwritten extents with user
      * data.
      */
     if (ext->e_flags != insert_rec->e_flags)
         return CONTIG_NONE;
 
     if (ocfs2_extents_adjacent(ext, insert_rec) &&
         ocfs2_block_extent_contig(sb, ext, blkno))
             return CONTIG_RIGHT;
 
     blkno = le64_to_cpu(ext->e_blkno);
     if (ocfs2_extents_adjacent(insert_rec, ext) &&
         ocfs2_block_extent_contig(sb, insert_rec, blkno))
         return CONTIG_LEFT;
 
     return CONTIG_NONE;
 }
 
 /*
  * NOTE: We can have pretty much any combination of contiguousness and
  * appending.
  *
  * The usefulness of APPEND_TAIL is more in that it lets us know that
  * we'll have to update the path to that leaf.
  */
 enum ocfs2_append_type {
     APPEND_NONE = 0,
     APPEND_TAIL,
 };
 
 enum ocfs2_split_type {
     SPLIT_NONE = 0,
     SPLIT_LEFT,
     SPLIT_RIGHT,
 };
 
 struct ocfs2_insert_type {
     enum ocfs2_split_type   ins_split;
     enum ocfs2_append_type  ins_appending;
     enum ocfs2_contig_type  ins_contig;
     int         ins_contig_index;
     int         ins_tree_depth;
 };
 
 struct ocfs2_merge_ctxt {
     enum ocfs2_contig_type  c_contig_type;
     int         c_has_empty_extent;
     int         c_split_covers_rec;
 };
 
 static int ocfs2_validate_extent_block(struct super_block *sb,
                        struct buffer_head *bh)
 {
     int rc;
     struct ocfs2_extent_block *eb =
         (struct ocfs2_extent_block *)bh->b_data;
 
     trace_ocfs2_validate_extent_block((unsigned long long)bh->b_blocknr);
 
     BUG_ON(!buffer_uptodate(bh));
 
     /*
      * If the ecc fails, we return the error but otherwise
      * leave the filesystem running.  We know any error is
      * local to this block.
      */
     rc = ocfs2_validate_meta_ecc(sb, bh->b_data, &eb->h_check);
     if (rc) {
         mlog(ML_ERROR, "Checksum failed for extent block %llu\n",
              (unsigned long long)bh->b_blocknr);
         return rc;
     }
 
     /*
      * Errors after here are fatal.
      */
 
     if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
         rc = ocfs2_error(sb,
                  "Extent block #%llu has bad signature %.*s\n",
                  (unsigned long long)bh->b_blocknr, 7,
                  eb->h_signature);
         goto bail;
     }
 
     if (le64_to_cpu(eb->h_blkno) != bh->b_blocknr) {
         rc = ocfs2_error(sb,
                  "Extent block #%llu has an invalid h_blkno of %llu\n",
                  (unsigned long long)bh->b_blocknr,
                  (unsigned long long)le64_to_cpu(eb->h_blkno));
         goto bail;
     }
 
     if (le32_to_cpu(eb->h_fs_generation) != OCFS2_SB(sb)->fs_generation)
         rc = ocfs2_error(sb,
                  "Extent block #%llu has an invalid h_fs_generation of #%u\n",
                  (unsigned long long)bh->b_blocknr,
                  le32_to_cpu(eb->h_fs_generation));
 bail:
     return rc;
 }
 
 int ocfs2_read_extent_block(struct ocfs2_caching_info *ci, u64 eb_blkno,
                 struct buffer_head **bh)
 {
     int rc;
     struct buffer_head *tmp = *bh;
 
     rc = ocfs2_read_block(ci, eb_blkno, &tmp,
                   ocfs2_validate_extent_block);
 
     /* If ocfs2_read_block() got us a new bh, pass it up. */
     if (!rc && !*bh)
         *bh = tmp;
 
     return rc;
 }
 
 
 /*
  * How many free extents have we got before we need more meta data?
  */
 int ocfs2_num_free_extents(struct ocfs2_extent_tree *et)
 {
     int retval;
     struct ocfs2_extent_list *el = NULL;
     struct ocfs2_extent_block *eb;
     struct buffer_head *eb_bh = NULL;
     u64 last_eb_blk = 0;
 
     el = et->et_root_el;
     last_eb_blk = ocfs2_et_get_last_eb_blk(et);
 
     if (last_eb_blk) {
         retval = ocfs2_read_extent_block(et->et_ci, last_eb_blk,
                          &eb_bh);
         if (retval < 0) {
             mlog_errno(retval);
             goto bail;
         }
         eb = (struct ocfs2_extent_block *) eb_bh->b_data;
         el = &eb->h_list;
     }
 
     BUG_ON(el->l_tree_depth != 0);
 
     retval = le16_to_cpu(el->l_count) - le16_to_cpu(el->l_next_free_rec);
 bail:
     brelse(eb_bh);
 
     trace_ocfs2_num_free_extents(retval);
     return retval;
 }
 
 /* expects array to already be allocated
  *
  * sets h_signature, h_blkno, h_suballoc_bit, h_suballoc_slot, and
  * l_count for you
  */
 static int ocfs2_create_new_meta_bhs(handle_t *handle,
                      struct ocfs2_extent_tree *et,
                      int wanted,
                      struct ocfs2_alloc_context *meta_ac,
                      struct buffer_head *bhs[])
 {
     int count, status, i;
     u16 suballoc_bit_start;
     u32 num_got;
     u64 suballoc_loc, first_blkno;
     struct ocfs2_super *osb =
         OCFS2_SB(ocfs2_metadata_cache_get_super(et->et_ci));
     struct ocfs2_extent_block *eb;
 
     count = 0;
     while (count < wanted) {
         status = ocfs2_claim_metadata(handle,
                           meta_ac,
                           wanted - count,
                           &suballoc_loc,
                           &suballoc_bit_start,
                           &num_got,
                           &first_blkno);
         if (status < 0) {
             mlog_errno(status);
             goto bail;
         }
 
         for(i = count;  i < (num_got + count); i++) {
             bhs[i] = sb_getblk(osb->sb, first_blkno);
             if (bhs[i] == NULL) {
                 status = -ENOMEM;
                 mlog_errno(status);
                 goto bail;
             }
             ocfs2_set_new_buffer_uptodate(et->et_ci, bhs[i]);
 
             status = ocfs2_journal_access_eb(handle, et->et_ci,
                              bhs[i],
                              OCFS2_JOURNAL_ACCESS_CREATE);
             if (status < 0) {
                 mlog_errno(status);
                 goto bail;
             }
 
             memset(bhs[i]->b_data, 0, osb->sb->s_blocksize);
             eb = (struct ocfs2_extent_block *) bhs[i]->b_data;
             /* Ok, setup the minimal stuff here. */
             strcpy(eb->h_signature, OCFS2_EXTENT_BLOCK_SIGNATURE);
             eb->h_blkno = cpu_to_le64(first_blkno);
             eb->h_fs_generation = cpu_to_le32(osb->fs_generation);
             eb->h_suballoc_slot =
                 cpu_to_le16(meta_ac->ac_alloc_slot);
             eb->h_suballoc_loc = cpu_to_le64(suballoc_loc);
             eb->h_suballoc_bit = cpu_to_le16(suballoc_bit_start);
             eb->h_list.l_count =
                 cpu_to_le16(ocfs2_extent_recs_per_eb(osb->sb));
 
             suballoc_bit_start++;
             first_blkno++;
 
             /* We'll also be dirtied by the caller, so
              * this isn't absolutely necessary. */
             ocfs2_journal_dirty(handle, bhs[i]);
         }
 
         count += num_got;
     }
 
     status = 0;
 bail:
     if (status < 0) {
         for(i = 0; i < wanted; i++) {
             brelse(bhs[i]);
             bhs[i] = NULL;
         }
     }
     return status;
 }
 
 /*
  * Helper function for ocfs2_add_branch() and ocfs2_shift_tree_depth().
  *
  * Returns the sum of the rightmost extent rec logical offset and
  * cluster count.
  *
  * ocfs2_add_branch() uses this to determine what logical cluster
  * value should be populated into the leftmost new branch records.
  *
  * ocfs2_shift_tree_depth() uses this to determine the # clusters
  * value for the new topmost tree record.
  */
 static inline u32 ocfs2_sum_rightmost_rec(struct ocfs2_extent_list  *el)
 {
     int i;
 
     i = le16_to_cpu(el->l_next_free_rec) - 1;
 
     return le32_to_cpu(el->l_recs[i].e_cpos) +
         ocfs2_rec_clusters(el, &el->l_recs[i]);
 }
 
 /*
  * Change range of the branches in the right most path according to the leaf
  * extent block's rightmost record.
  */
 static int ocfs2_adjust_rightmost_branch(handle_t *handle,
                      struct ocfs2_extent_tree *et)
 {
     int status;
     struct ocfs2_path *path = NULL;
     struct ocfs2_extent_list *el;
     struct ocfs2_extent_rec *rec;
 
     path = ocfs2_new_path_from_et(et);
     if (!path) {
         status = -ENOMEM;
         return status;
     }
 
     status = ocfs2_find_path(et->et_ci, path, UINT_MAX);
     if (status < 0) {
         mlog_errno(status);
         goto out;
     }
 
     status = ocfs2_extend_trans(handle, path_num_items(path));
     if (status < 0) {
         mlog_errno(status);
         goto out;
     }
 
     status = ocfs2_journal_access_path(et->et_ci, handle, path);
     if (status < 0) {
         mlog_errno(status);
         goto out;
     }
 
     el = path_leaf_el(path);
     rec = &el->l_recs[le16_to_cpu(el->l_next_free_rec) - 1];
 
     ocfs2_adjust_rightmost_records(handle, et, path, rec);
 
 out:
     ocfs2_free_path(path);
     return status;
 }
 
 /*
  * Add an entire tree branch to our inode. eb_bh is the extent block
  * to start at, if we don't want to start the branch at the root
  * structure.
  *
  * last_eb_bh is required as we have to update it's next_leaf pointer
  * for the new last extent block.
  *
  * the new branch will be 'empty' in the sense that every block will
  * contain a single record with cluster count == 0.
  */
 static int ocfs2_add_branch(handle_t *handle,
                 struct ocfs2_extent_tree *et,
                 struct buffer_head *eb_bh,
                 struct buffer_head **last_eb_bh,
                 struct ocfs2_alloc_context *meta_ac)
 {
     int status, new_blocks, i, block_given = 0;
     u64 next_blkno, new_last_eb_blk;
     struct buffer_head *bh;
     struct buffer_head **new_eb_bhs = NULL;
     struct ocfs2_extent_block *eb;
     struct ocfs2_extent_list  *eb_el;
     struct ocfs2_extent_list  *el;
     u32 new_cpos, root_end;
 
     BUG_ON(!last_eb_bh || !*last_eb_bh);
 
     if (eb_bh) {
         eb = (struct ocfs2_extent_block *) eb_bh->b_data;
         el = &eb->h_list;
     } else
         el = et->et_root_el;
 
     /* we never add a branch to a leaf. */
     BUG_ON(!el->l_tree_depth);
 
     new_blocks = le16_to_cpu(el->l_tree_depth);
 
     eb = (struct ocfs2_extent_block *)(*last_eb_bh)->b_data;
     new_cpos = ocfs2_sum_rightmost_rec(&eb->h_list);
     root_end = ocfs2_sum_rightmost_rec(et->et_root_el);
 
     /*
      * If there is a gap before the root end and the real end
      * of the righmost leaf block, we need to remove the gap
      * between new_cpos and root_end first so that the tree
      * is consistent after we add a new branch(it will start
      * from new_cpos).
      */
     if (root_end > new_cpos) {
         trace_ocfs2_adjust_rightmost_branch(
             (unsigned long long)
             ocfs2_metadata_cache_owner(et->et_ci),
             root_end, new_cpos);
 
         status = ocfs2_adjust_rightmost_branch(handle, et);
         if (status) {
             mlog_errno(status);
             goto bail;
         }
     }
 
     /* allocate the number of new eb blocks we need */
     new_eb_bhs = kcalloc(new_blocks, sizeof(struct buffer_head *),
                  GFP_KERNEL);
     if (!new_eb_bhs) {
         status = -ENOMEM;
         mlog_errno(status);
         goto bail;
     }
 
     /* Firstyly, try to reuse dealloc since we have already estimated how
      * many extent blocks we may use.
      */
     if (!ocfs2_is_dealloc_empty(et)) {
         status = ocfs2_reuse_blk_from_dealloc(handle, et,
                               new_eb_bhs, new_blocks,
                               &block_given);
         if (status < 0) {
             mlog_errno(status);
             goto bail;
         }
     }
 
     BUG_ON(block_given > new_blocks);
 
     if (block_given < new_blocks) {
         BUG_ON(!meta_ac);
         status = ocfs2_create_new_meta_bhs(handle, et,
                            new_blocks - block_given,
                            meta_ac,
                            &new_eb_bhs[block_given]);
         if (status < 0) {
             mlog_errno(status);
             goto bail;
         }
     }
 
     /* Note: new_eb_bhs[new_blocks - 1] is the guy which will be
      * linked with the rest of the tree.
      * conversly, new_eb_bhs[0] is the new bottommost leaf.
      *
      * when we leave the loop, new_last_eb_blk will point to the
      * newest leaf, and next_blkno will point to the topmost extent
      * block. */
     next_blkno = new_last_eb_blk = 0;
     for(i = 0; i < new_blocks; i++) {
         bh = new_eb_bhs[i];
         eb = (struct ocfs2_extent_block *) bh->b_data;
         /* ocfs2_create_new_meta_bhs() should create it right! */
         BUG_ON(!OCFS2_IS_VALID_EXTENT_BLOCK(eb));
         eb_el = &eb->h_list;
 
         status = ocfs2_journal_access_eb(handle, et->et_ci, bh,
                          OCFS2_JOURNAL_ACCESS_CREATE);
         if (status < 0) {
             mlog_errno(status);
             goto bail;
         }
 
         eb->h_next_leaf_blk = 0;
         eb_el->l_tree_depth = cpu_to_le16(i);
         eb_el->l_next_free_rec = cpu_to_le16(1);
         /*
          * This actually counts as an empty extent as
          * c_clusters == 0
          */
         eb_el->l_recs[0].e_cpos = cpu_to_le32(new_cpos);
         eb_el->l_recs[0].e_blkno = cpu_to_le64(next_blkno);
         /*
          * eb_el isn't always an interior node, but even leaf
          * nodes want a zero'd flags and reserved field so
          * this gets the whole 32 bits regardless of use.
          */
         eb_el->l_recs[0].e_int_clusters = cpu_to_le32(0);
         if (!eb_el->l_tree_depth)
             new_last_eb_blk = le64_to_cpu(eb->h_blkno);
 
         ocfs2_journal_dirty(handle, bh);
         next_blkno = le64_to_cpu(eb->h_blkno);
     }
 
     /* This is a bit hairy. We want to update up to three blocks
      * here without leaving any of them in an inconsistent state
      * in case of error. We don't have to worry about
      * journal_dirty erroring as it won't unless we've aborted the
      * handle (in which case we would never be here) so reserving
      * the write with journal_access is all we need to do. */
     status = ocfs2_journal_access_eb(handle, et->et_ci, *last_eb_bh,
                      OCFS2_JOURNAL_ACCESS_WRITE);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
     status = ocfs2_et_root_journal_access(handle, et,
                           OCFS2_JOURNAL_ACCESS_WRITE);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
     if (eb_bh) {
         status = ocfs2_journal_access_eb(handle, et->et_ci, eb_bh,
                          OCFS2_JOURNAL_ACCESS_WRITE);
         if (status < 0) {
             mlog_errno(status);
             goto bail;
         }
     }
 
     /* Link the new branch into the rest of the tree (el will
      * either be on the root_bh, or the extent block passed in. */
     i = le16_to_cpu(el->l_next_free_rec);
     el->l_recs[i].e_blkno = cpu_to_le64(next_blkno);
     el->l_recs[i].e_cpos = cpu_to_le32(new_cpos);
     el->l_recs[i].e_int_clusters = 0;
     le16_add_cpu(&el->l_next_free_rec, 1);
 
     /* fe needs a new last extent block pointer, as does the
      * next_leaf on the previously last-extent-block. */
     ocfs2_et_set_last_eb_blk(et, new_last_eb_blk);
 
     eb = (struct ocfs2_extent_block *) (*last_eb_bh)->b_data;
     eb->h_next_leaf_blk = cpu_to_le64(new_last_eb_blk);
 
     ocfs2_journal_dirty(handle, *last_eb_bh);
     ocfs2_journal_dirty(handle, et->et_root_bh);
     if (eb_bh)
         ocfs2_journal_dirty(handle, eb_bh);
 
     /*
      * Some callers want to track the rightmost leaf so pass it
      * back here.
      */
     brelse(*last_eb_bh);
     get_bh(new_eb_bhs[0]);
     *last_eb_bh = new_eb_bhs[0];
 
     status = 0;
 bail:
     if (new_eb_bhs) {
         for (i = 0; i < new_blocks; i++)
             brelse(new_eb_bhs[i]);
         kfree(new_eb_bhs);
     }
 
     return status;
 }
 
 /*
  * adds another level to the allocation tree.
  * returns back the new extent block so you can add a branch to it
  * after this call.
  */
 static int ocfs2_shift_tree_depth(handle_t *handle,
                   struct ocfs2_extent_tree *et,
                   struct ocfs2_alloc_context *meta_ac,
                   struct buffer_head **ret_new_eb_bh)
 {
     int status, i, block_given = 0;
     u32 new_clusters;
     struct buffer_head *new_eb_bh = NULL;
     struct ocfs2_extent_block *eb;
     struct ocfs2_extent_list  *root_el;
     struct ocfs2_extent_list  *eb_el;
 
     if (!ocfs2_is_dealloc_empty(et)) {
         status = ocfs2_reuse_blk_from_dealloc(handle, et,
                               &new_eb_bh, 1,
                               &block_given);
     } else if (meta_ac) {
         status = ocfs2_create_new_meta_bhs(handle, et, 1, meta_ac,
                            &new_eb_bh);
 
     } else {
         BUG();
     }
 
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     eb = (struct ocfs2_extent_block *) new_eb_bh->b_data;
     /* ocfs2_create_new_meta_bhs() should create it right! */
     BUG_ON(!OCFS2_IS_VALID_EXTENT_BLOCK(eb));
 
     eb_el = &eb->h_list;
     root_el = et->et_root_el;
 
     status = ocfs2_journal_access_eb(handle, et->et_ci, new_eb_bh,
                      OCFS2_JOURNAL_ACCESS_CREATE);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     /* copy the root extent list data into the new extent block */
     eb_el->l_tree_depth = root_el->l_tree_depth;
     eb_el->l_next_free_rec = root_el->l_next_free_rec;
     for (i = 0; i < le16_to_cpu(root_el->l_next_free_rec); i++)
         eb_el->l_recs[i] = root_el->l_recs[i];
 
     ocfs2_journal_dirty(handle, new_eb_bh);
 
     status = ocfs2_et_root_journal_access(handle, et,
                           OCFS2_JOURNAL_ACCESS_WRITE);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     new_clusters = ocfs2_sum_rightmost_rec(eb_el);
 
     /* update root_bh now */
     le16_add_cpu(&root_el->l_tree_depth, 1);
     root_el->l_recs[0].e_cpos = 0;
     root_el->l_recs[0].e_blkno = eb->h_blkno;
     root_el->l_recs[0].e_int_clusters = cpu_to_le32(new_clusters);
     for (i = 1; i < le16_to_cpu(root_el->l_next_free_rec); i++)
         memset(&root_el->l_recs[i], 0, sizeof(struct ocfs2_extent_rec));
     root_el->l_next_free_rec = cpu_to_le16(1);
 
     /* If this is our 1st tree depth shift, then last_eb_blk
      * becomes the allocated extent block */
     if (root_el->l_tree_depth == cpu_to_le16(1))
         ocfs2_et_set_last_eb_blk(et, le64_to_cpu(eb->h_blkno));
 
     ocfs2_journal_dirty(handle, et->et_root_bh);
 
     *ret_new_eb_bh = new_eb_bh;
     new_eb_bh = NULL;
     status = 0;
 bail:
     brelse(new_eb_bh);
 
     return status;
 }
 
 /*
  * Should only be called when there is no space left in any of the
  * leaf nodes. What we want to do is find the lowest tree depth
  * non-leaf extent block with room for new records. There are three
  * valid results of this search:
  *
  * 1) a lowest extent block is found, then we pass it back in
  *    *lowest_eb_bh and return '0'
  *
  * 2) the search fails to find anything, but the root_el has room. We
  *    pass NULL back in *lowest_eb_bh, but still return '0'
  *
  * 3) the search fails to find anything AND the root_el is full, in
  *    which case we return > 0
  *
  * return status < 0 indicates an error.
  */
 static int ocfs2_find_branch_target(struct ocfs2_extent_tree *et,
                     struct buffer_head **target_bh)
 {
     int status = 0, i;
     u64 blkno;
     struct ocfs2_extent_block *eb;
     struct ocfs2_extent_list  *el;
     struct buffer_head *bh = NULL;
     struct buffer_head *lowest_bh = NULL;
 
     *target_bh = NULL;
 
     el = et->et_root_el;
 
     while(le16_to_cpu(el->l_tree_depth) > 1) {
         if (le16_to_cpu(el->l_next_free_rec) == 0) {
             status = ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
                     "Owner %llu has empty extent list (next_free_rec == 0)\n",
                     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci));
             goto bail;
         }
         i = le16_to_cpu(el->l_next_free_rec) - 1;
         blkno = le64_to_cpu(el->l_recs[i].e_blkno);
         if (!blkno) {
             status = ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
                     "Owner %llu has extent list where extent # %d has no physical block start\n",
                     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci), i);
             goto bail;
         }
 
         brelse(bh);
         bh = NULL;
 
         status = ocfs2_read_extent_block(et->et_ci, blkno, &bh);
         if (status < 0) {
             mlog_errno(status);
             goto bail;
         }
 
         eb = (struct ocfs2_extent_block *) bh->b_data;
         el = &eb->h_list;
 
         if (le16_to_cpu(el->l_next_free_rec) <
             le16_to_cpu(el->l_count)) {
             brelse(lowest_bh);
             lowest_bh = bh;
             get_bh(lowest_bh);
         }
     }
 
     /* If we didn't find one and the fe doesn't have any room,
      * then return '1' */
     el = et->et_root_el;
     if (!lowest_bh && (el->l_next_free_rec == el->l_count))
         status = 1;
 
     *target_bh = lowest_bh;
 bail:
     brelse(bh);
 
     return status;
 }
 
 /*
  * Grow a b-tree so that it has more records.
  *
  * We might shift the tree depth in which case existing paths should
  * be considered invalid.
  *
  * Tree depth after the grow is returned via *final_depth.
  *
  * *last_eb_bh will be updated by ocfs2_add_branch().
  */
 static int ocfs2_grow_tree(handle_t *handle, struct ocfs2_extent_tree *et,
                int *final_depth, struct buffer_head **last_eb_bh,
                struct ocfs2_alloc_context *meta_ac)
 {
     int ret, shift;
     struct ocfs2_extent_list *el = et->et_root_el;
     int depth = le16_to_cpu(el->l_tree_depth);
     struct buffer_head *bh = NULL;
 
     BUG_ON(meta_ac == NULL && ocfs2_is_dealloc_empty(et));
 
     shift = ocfs2_find_branch_target(et, &bh);
     if (shift < 0) {
         ret = shift;
         mlog_errno(ret);
         goto out;
     }
 
     /* We traveled all the way to the bottom of the allocation tree
      * and didn't find room for any more extents - we need to add
      * another tree level */
     if (shift) {
         BUG_ON(bh);
         trace_ocfs2_grow_tree(
             (unsigned long long)
             ocfs2_metadata_cache_owner(et->et_ci),
             depth);
 
         /* ocfs2_shift_tree_depth will return us a buffer with
          * the new extent block (so we can pass that to
          * ocfs2_add_branch). */
         ret = ocfs2_shift_tree_depth(handle, et, meta_ac, &bh);
         if (ret < 0) {
             mlog_errno(ret);
             goto out;
         }
         depth++;
         if (depth == 1) {
             /*
              * Special case: we have room now if we shifted from
              * tree_depth 0, so no more work needs to be done.
              *
              * We won't be calling add_branch, so pass
              * back *last_eb_bh as the new leaf. At depth
              * zero, it should always be null so there's
              * no reason to brelse.
              */
             BUG_ON(*last_eb_bh);
             get_bh(bh);
             *last_eb_bh = bh;
             goto out;
         }
     }
 
     /* call ocfs2_add_branch to add the final part of the tree with
      * the new data. */
     ret = ocfs2_add_branch(handle, et, bh, last_eb_bh,
                    meta_ac);
     if (ret < 0)
         mlog_errno(ret);
 
 out:
     if (final_depth)
         *final_depth = depth;
     brelse(bh);
     return ret;
 }
 
 /*
  * This function will discard the rightmost extent record.
  */
 static void ocfs2_shift_records_right(struct ocfs2_extent_list *el)
 {
     int next_free = le16_to_cpu(el->l_next_free_rec);
     int count = le16_to_cpu(el->l_count);
     unsigned int num_bytes;
 
     BUG_ON(!next_free);
     /* This will cause us to go off the end of our extent list. */
     BUG_ON(next_free >= count);
 
     num_bytes = sizeof(struct ocfs2_extent_rec) * next_free;
 
     memmove(&el->l_recs[1], &el->l_recs[0], num_bytes);
 }
 
 static void ocfs2_rotate_leaf(struct ocfs2_extent_list *el,
                   struct ocfs2_extent_rec *insert_rec)
 {
     int i, insert_index, next_free, has_empty, num_bytes;
     u32 insert_cpos = le32_to_cpu(insert_rec->e_cpos);
     struct ocfs2_extent_rec *rec;
 
     next_free = le16_to_cpu(el->l_next_free_rec);
     has_empty = ocfs2_is_empty_extent(&el->l_recs[0]);
 
     BUG_ON(!next_free);
 
     /* The tree code before us didn't allow enough room in the leaf. */
     BUG_ON(el->l_next_free_rec == el->l_count && !has_empty);
 
     /*
      * The easiest way to approach this is to just remove the
      * empty extent and temporarily decrement next_free.
      */
     if (has_empty) {
         /*
          * If next_free was 1 (only an empty extent), this
          * loop won't execute, which is fine. We still want
          * the decrement above to happen.
          */
         for(i = 0; i < (next_free - 1); i++)
             el->l_recs[i] = el->l_recs[i+1];
 
         next_free--;
     }
 
     /*
      * Figure out what the new record index should be.
      */
     for(i = 0; i < next_free; i++) {
         rec = &el->l_recs[i];
 
         if (insert_cpos < le32_to_cpu(rec->e_cpos))
             break;
     }
     insert_index = i;
 
     trace_ocfs2_rotate_leaf(insert_cpos, insert_index,
                 has_empty, next_free,
                 le16_to_cpu(el->l_count));
 
     BUG_ON(insert_index < 0);
     BUG_ON(insert_index >= le16_to_cpu(el->l_count));
     BUG_ON(insert_index > next_free);
 
     /*
      * No need to memmove if we're just adding to the tail.
      */
     if (insert_index != next_free) {
         BUG_ON(next_free >= le16_to_cpu(el->l_count));
 
         num_bytes = next_free - insert_index;
         num_bytes *= sizeof(struct ocfs2_extent_rec);
         memmove(&el->l_recs[insert_index + 1],
             &el->l_recs[insert_index],
             num_bytes);
     }
 
     /*
      * Either we had an empty extent, and need to re-increment or
      * there was no empty extent on a non full rightmost leaf node,
      * in which case we still need to increment.
      */
     next_free++;
     el->l_next_free_rec = cpu_to_le16(next_free);
     /*
      * Make sure none of the math above just messed up our tree.
      */
     BUG_ON(le16_to_cpu(el->l_next_free_rec) > le16_to_cpu(el->l_count));
 
     el->l_recs[insert_index] = *insert_rec;
 
 }
 
 static void ocfs2_remove_empty_extent(struct ocfs2_extent_list *el)
 {
     int size, num_recs = le16_to_cpu(el->l_next_free_rec);
 
     BUG_ON(num_recs == 0);
 
     if (ocfs2_is_empty_extent(&el->l_recs[0])) {
         num_recs--;
         size = num_recs * sizeof(struct ocfs2_extent_rec);
         memmove(&el->l_recs[0], &el->l_recs[1], size);
         memset(&el->l_recs[num_recs], 0,
                sizeof(struct ocfs2_extent_rec));
         el->l_next_free_rec = cpu_to_le16(num_recs);
     }
 }
 
 /*
  * Create an empty extent record .
  *
  * l_next_free_rec may be updated.
  *
  * If an empty extent already exists do nothing.
  */
 static void ocfs2_create_empty_extent(struct ocfs2_extent_list *el)
 {
     int next_free = le16_to_cpu(el->l_next_free_rec);
 
     BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
 
     if (next_free == 0)
         goto set_and_inc;
 
     if (ocfs2_is_empty_extent(&el->l_recs[0]))
         return;
 
     mlog_bug_on_msg(el->l_count == el->l_next_free_rec,
             "Asked to create an empty extent in a full list:\n"
             "count = %u, tree depth = %u",
             le16_to_cpu(el->l_count),
             le16_to_cpu(el->l_tree_depth));
 
     ocfs2_shift_records_right(el);
 
 set_and_inc:
     le16_add_cpu(&el->l_next_free_rec, 1);
     memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
 }
 
 /*
  * For a rotation which involves two leaf nodes, the "root node" is
  * the lowest level tree node which contains a path to both leafs. This
  * resulting set of information can be used to form a complete "subtree"
  *
  * This function is passed two full paths from the dinode down to a
  * pair of adjacent leaves. It's task is to figure out which path
  * index contains the subtree root - this can be the root index itself
  * in a worst-case rotation.
  *
  * The array index of the subtree root is passed back.
  */
 int ocfs2_find_subtree_root(struct ocfs2_extent_tree *et,
                 struct ocfs2_path *left,
                 struct ocfs2_path *right)
 {
     int i = 0;
 
     /*
      * Check that the caller passed in two paths from the same tree.
      */
     BUG_ON(path_root_bh(left) != path_root_bh(right));
 
     do {
         i++;
 
         /*
          * The caller didn't pass two adjacent paths.
          */
         mlog_bug_on_msg(i > left->p_tree_depth,
                 "Owner %llu, left depth %u, right depth %u\n"
                 "left leaf blk %llu, right leaf blk %llu\n",
                 (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
                 left->p_tree_depth, right->p_tree_depth,
                 (unsigned long long)path_leaf_bh(left)->b_blocknr,
                 (unsigned long long)path_leaf_bh(right)->b_blocknr);
     } while (left->p_node[i].bh->b_blocknr ==
          right->p_node[i].bh->b_blocknr);
 
     return i - 1;
 }
 
 typedef void (path_insert_t)(void *, struct buffer_head *);
 
 /*
  * Traverse a btree path in search of cpos, starting at root_el.
  *
  * This code can be called with a cpos larger than the tree, in which
  * case it will return the rightmost path.
  */
 static int __ocfs2_find_path(struct ocfs2_caching_info *ci,
                  struct ocfs2_extent_list *root_el, u32 cpos,
                  path_insert_t *func, void *data)
 {
     int i, ret = 0;
     u32 range;
     u64 blkno;
     struct buffer_head *bh = NULL;
     struct ocfs2_extent_block *eb;
     struct ocfs2_extent_list *el;
     struct ocfs2_extent_rec *rec;
 
     el = root_el;
     while (el->l_tree_depth) {
         if (le16_to_cpu(el->l_next_free_rec) == 0) {
             ocfs2_error(ocfs2_metadata_cache_get_super(ci),
                     "Owner %llu has empty extent list at depth %u\n",
                     (unsigned long long)ocfs2_metadata_cache_owner(ci),
                     le16_to_cpu(el->l_tree_depth));
             ret = -EROFS;
             goto out;
 
         }
 
         for(i = 0; i < le16_to_cpu(el->l_next_free_rec) - 1; i++) {
             rec = &el->l_recs[i];
 
             /*
              * In the case that cpos is off the allocation
              * tree, this should just wind up returning the
              * rightmost record.
              */
             range = le32_to_cpu(rec->e_cpos) +
                 ocfs2_rec_clusters(el, rec);
             if (cpos >= le32_to_cpu(rec->e_cpos) && cpos < range)
                 break;
         }
 
         blkno = le64_to_cpu(el->l_recs[i].e_blkno);
         if (blkno == 0) {
             ocfs2_error(ocfs2_metadata_cache_get_super(ci),
                     "Owner %llu has bad blkno in extent list at depth %u (index %d)\n",
                     (unsigned long long)ocfs2_metadata_cache_owner(ci),
                     le16_to_cpu(el->l_tree_depth), i);
             ret = -EROFS;
             goto out;
         }
 
         brelse(bh);
         bh = NULL;
         ret = ocfs2_read_extent_block(ci, blkno, &bh);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         eb = (struct ocfs2_extent_block *) bh->b_data;
         el = &eb->h_list;
 
         if (le16_to_cpu(el->l_next_free_rec) >
             le16_to_cpu(el->l_count)) {
             ocfs2_error(ocfs2_metadata_cache_get_super(ci),
                     "Owner %llu has bad count in extent list at block %llu (next free=%u, count=%u)\n",
                     (unsigned long long)ocfs2_metadata_cache_owner(ci),
                     (unsigned long long)bh->b_blocknr,
                     le16_to_cpu(el->l_next_free_rec),
                     le16_to_cpu(el->l_count));
             ret = -EROFS;
             goto out;
         }
 
         if (func)
             func(data, bh);
     }
 
 out:
     /*
      * Catch any trailing bh that the loop didn't handle.
      */
     brelse(bh);
 
     return ret;
 }
 
 /*
  * Given an initialized path (that is, it has a valid root extent
  * list), this function will traverse the btree in search of the path
  * which would contain cpos.
  *
  * The path traveled is recorded in the path structure.
  *
  * Note that this will not do any comparisons on leaf node extent
  * records, so it will work fine in the case that we just added a tree
  * branch.
  */
 struct find_path_data {
     int index;
     struct ocfs2_path *path;
 };
 static void find_path_ins(void *data, struct buffer_head *bh)
 {
     struct find_path_data *fp = data;
 
     get_bh(bh);
     ocfs2_path_insert_eb(fp->path, fp->index, bh);
     fp->index++;
 }
 int ocfs2_find_path(struct ocfs2_caching_info *ci,
             struct ocfs2_path *path, u32 cpos)
 {
     struct find_path_data data;
 
     data.index = 1;
     data.path = path;
     return __ocfs2_find_path(ci, path_root_el(path), cpos,
                  find_path_ins, &data);
 }
 
 static void find_leaf_ins(void *data, struct buffer_head *bh)
 {
     struct ocfs2_extent_block *eb =(struct ocfs2_extent_block *)bh->b_data;
     struct ocfs2_extent_list *el = &eb->h_list;
     struct buffer_head **ret = data;
 
     /* We want to retain only the leaf block. */
     if (le16_to_cpu(el->l_tree_depth) == 0) {
         get_bh(bh);
         *ret = bh;
     }
 }
 /*
  * Find the leaf block in the tree which would contain cpos. No
  * checking of the actual leaf is done.
  *
  * Some paths want to call this instead of allocating a path structure
  * and calling ocfs2_find_path().
  *
  * This function doesn't handle non btree extent lists.
  */
 int ocfs2_find_leaf(struct ocfs2_caching_info *ci,
             struct ocfs2_extent_list *root_el, u32 cpos,
             struct buffer_head **leaf_bh)
 {
     int ret;
     struct buffer_head *bh = NULL;
 
     ret = __ocfs2_find_path(ci, root_el, cpos, find_leaf_ins, &bh);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     *leaf_bh = bh;
 out:
     return ret;
 }
 
 /*
  * Adjust the adjacent records (left_rec, right_rec) involved in a rotation.
  *
  * Basically, we've moved stuff around at the bottom of the tree and
  * we need to fix up the extent records above the changes to reflect
  * the new changes.
  *
  * left_rec: the record on the left.
  * right_rec: the record to the right of left_rec
  * right_child_el: is the child list pointed to by right_rec
  *
  * By definition, this only works on interior nodes.
  */
 static void ocfs2_adjust_adjacent_records(struct ocfs2_extent_rec *left_rec,
                   struct ocfs2_extent_rec *right_rec,
                   struct ocfs2_extent_list *right_child_el)
 {
     u32 left_clusters, right_end;
 
     /*
      * Interior nodes never have holes. Their cpos is the cpos of
      * the leftmost record in their child list. Their cluster
      * count covers the full theoretical range of their child list
      * - the range between their cpos and the cpos of the record
      * immediately to their right.
      */
     left_clusters = le32_to_cpu(right_child_el->l_recs[0].e_cpos);
     if (!ocfs2_rec_clusters(right_child_el, &right_child_el->l_recs[0])) {
         BUG_ON(right_child_el->l_tree_depth);
         BUG_ON(le16_to_cpu(right_child_el->l_next_free_rec) <= 1);
         left_clusters = le32_to_cpu(right_child_el->l_recs[1].e_cpos);
     }
     left_clusters -= le32_to_cpu(left_rec->e_cpos);
     left_rec->e_int_clusters = cpu_to_le32(left_clusters);
 
     /*
      * Calculate the rightmost cluster count boundary before
      * moving cpos - we will need to adjust clusters after
      * updating e_cpos to keep the same highest cluster count.
      */
     right_end = le32_to_cpu(right_rec->e_cpos);
     right_end += le32_to_cpu(right_rec->e_int_clusters);
 
     right_rec->e_cpos = left_rec->e_cpos;
     le32_add_cpu(&right_rec->e_cpos, left_clusters);
 
     right_end -= le32_to_cpu(right_rec->e_cpos);
     right_rec->e_int_clusters = cpu_to_le32(right_end);
 }
 
 /*
  * Adjust the adjacent root node records involved in a
  * rotation. left_el_blkno is passed in as a key so that we can easily
  * find it's index in the root list.
  */
 static void ocfs2_adjust_root_records(struct ocfs2_extent_list *root_el,
                       struct ocfs2_extent_list *left_el,
                       struct ocfs2_extent_list *right_el,
                       u64 left_el_blkno)
 {
     int i;
 
     BUG_ON(le16_to_cpu(root_el->l_tree_depth) <=
            le16_to_cpu(left_el->l_tree_depth));
 
     for(i = 0; i < le16_to_cpu(root_el->l_next_free_rec) - 1; i++) {
         if (le64_to_cpu(root_el->l_recs[i].e_blkno) == left_el_blkno)
             break;
     }
 
     /*
      * The path walking code should have never returned a root and
      * two paths which are not adjacent.
      */
     BUG_ON(i >= (le16_to_cpu(root_el->l_next_free_rec) - 1));
 
     ocfs2_adjust_adjacent_records(&root_el->l_recs[i],
                       &root_el->l_recs[i + 1], right_el);
 }
 
 /*
  * We've changed a leaf block (in right_path) and need to reflect that
  * change back up the subtree.
  *
  * This happens in multiple places:
  *   - When we've moved an extent record from the left path leaf to the right
  *     path leaf to make room for an empty extent in the left path leaf.
  *   - When our insert into the right path leaf is at the leftmost edge
  *     and requires an update of the path immediately to it's left. This
  *     can occur at the end of some types of rotation and appending inserts.
  *   - When we've adjusted the last extent record in the left path leaf and the
  *     1st extent record in the right path leaf during cross extent block merge.
  */
 static void ocfs2_complete_edge_insert(handle_t *handle,
                        struct ocfs2_path *left_path,
                        struct ocfs2_path *right_path,
                        int subtree_index)
 {
     int i, idx;
     struct ocfs2_extent_list *el, *left_el, *right_el;
     struct ocfs2_extent_rec *left_rec, *right_rec;
     struct buffer_head *root_bh;
 
     /*
      * Update the counts and position values within all the
      * interior nodes to reflect the leaf rotation we just did.
      *
      * The root node is handled below the loop.
      *
      * We begin the loop with right_el and left_el pointing to the
      * leaf lists and work our way up.
      *
      * NOTE: within this loop, left_el and right_el always refer
      * to the *child* lists.
      */
     left_el = path_leaf_el(left_path);
     right_el = path_leaf_el(right_path);
     for(i = left_path->p_tree_depth - 1; i > subtree_index; i--) {
         trace_ocfs2_complete_edge_insert(i);
 
         /*
          * One nice property of knowing that all of these
          * nodes are below the root is that we only deal with
          * the leftmost right node record and the rightmost
          * left node record.
          */
         el = left_path->p_node[i].el;
         idx = le16_to_cpu(left_el->l_next_free_rec) - 1;
         left_rec = &el->l_recs[idx];
 
         el = right_path->p_node[i].el;
         right_rec = &el->l_recs[0];
 
         ocfs2_adjust_adjacent_records(left_rec, right_rec, right_el);
 
         ocfs2_journal_dirty(handle, left_path->p_node[i].bh);
         ocfs2_journal_dirty(handle, right_path->p_node[i].bh);
 
         /*
          * Setup our list pointers now so that the current
          * parents become children in the next iteration.
          */
         left_el = left_path->p_node[i].el;
         right_el = right_path->p_node[i].el;
     }
 
     /*
      * At the root node, adjust the two adjacent records which
      * begin our path to the leaves.
      */
 
     el = left_path->p_node[subtree_index].el;
     left_el = left_path->p_node[subtree_index + 1].el;
     right_el = right_path->p_node[subtree_index + 1].el;
 
     ocfs2_adjust_root_records(el, left_el, right_el,
                   left_path->p_node[subtree_index + 1].bh->b_blocknr);
 
     root_bh = left_path->p_node[subtree_index].bh;
 
     ocfs2_journal_dirty(handle, root_bh);
 }
 
 static int ocfs2_rotate_subtree_right(handle_t *handle,
                       struct ocfs2_extent_tree *et,
                       struct ocfs2_path *left_path,
                       struct ocfs2_path *right_path,
                       int subtree_index)
 {
     int ret, i;
     struct buffer_head *right_leaf_bh;
     struct buffer_head *left_leaf_bh = NULL;
     struct buffer_head *root_bh;
     struct ocfs2_extent_list *right_el, *left_el;
     struct ocfs2_extent_rec move_rec;
 
     left_leaf_bh = path_leaf_bh(left_path);
     left_el = path_leaf_el(left_path);
 
     if (left_el->l_next_free_rec != left_el->l_count) {
         ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
                 "Inode %llu has non-full interior leaf node %llu (next free = %u)\n",
                 (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
                 (unsigned long long)left_leaf_bh->b_blocknr,
                 le16_to_cpu(left_el->l_next_free_rec));
         return -EROFS;
     }
 
     /*
      * This extent block may already have an empty record, so we
      * return early if so.
      */
     if (ocfs2_is_empty_extent(&left_el->l_recs[0]))
         return 0;
 
     root_bh = left_path->p_node[subtree_index].bh;
     BUG_ON(root_bh != right_path->p_node[subtree_index].bh);
 
     ret = ocfs2_path_bh_journal_access(handle, et->et_ci, right_path,
                        subtree_index);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     for(i = subtree_index + 1; i < path_num_items(right_path); i++) {
         ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
                            right_path, i);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
                            left_path, i);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     right_leaf_bh = path_leaf_bh(right_path);
     right_el = path_leaf_el(right_path);
 
     /* This is a code error, not a disk corruption. */
     mlog_bug_on_msg(!right_el->l_next_free_rec, "Inode %llu: Rotate fails "
             "because rightmost leaf block %llu is empty\n",
             (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
             (unsigned long long)right_leaf_bh->b_blocknr);
 
     ocfs2_create_empty_extent(right_el);
 
     ocfs2_journal_dirty(handle, right_leaf_bh);
 
     /* Do the copy now. */
     i = le16_to_cpu(left_el->l_next_free_rec) - 1;
     move_rec = left_el->l_recs[i];
     right_el->l_recs[0] = move_rec;
 
     /*
      * Clear out the record we just copied and shift everything
      * over, leaving an empty extent in the left leaf.
      *
      * We temporarily subtract from next_free_rec so that the
      * shift will lose the tail record (which is now defunct).
      */
     le16_add_cpu(&left_el->l_next_free_rec, -1);
     ocfs2_shift_records_right(left_el);
     memset(&left_el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
     le16_add_cpu(&left_el->l_next_free_rec, 1);
 
     ocfs2_journal_dirty(handle, left_leaf_bh);
 
     ocfs2_complete_edge_insert(handle, left_path, right_path,
                    subtree_index);
 
 out:
     return ret;
 }
 
 /*
  * Given a full path, determine what cpos value would return us a path
  * containing the leaf immediately to the left of the current one.
  *
  * Will return zero if the path passed in is already the leftmost path.
  */
 int ocfs2_find_cpos_for_left_leaf(struct super_block *sb,
                   struct ocfs2_path *path, u32 *cpos)
 {
     int i, j, ret = 0;
     u64 blkno;
     struct ocfs2_extent_list *el;
 
     BUG_ON(path->p_tree_depth == 0);
 
     *cpos = 0;
 
     blkno = path_leaf_bh(path)->b_blocknr;
 
     /* Start at the tree node just above the leaf and work our way up. */
     i = path->p_tree_depth - 1;
     while (i >= 0) {
         el = path->p_node[i].el;
 
         /*
          * Find the extent record just before the one in our
          * path.
          */
         for(j = 0; j < le16_to_cpu(el->l_next_free_rec); j++) {
             if (le64_to_cpu(el->l_recs[j].e_blkno) == blkno) {
                 if (j == 0) {
                     if (i == 0) {
                         /*
                          * We've determined that the
                          * path specified is already
                          * the leftmost one - return a
                          * cpos of zero.
                          */
                         goto out;
                     }
                     /*
                      * The leftmost record points to our
                      * leaf - we need to travel up the
                      * tree one level.
                      */
                     goto next_node;
                 }
 
                 *cpos = le32_to_cpu(el->l_recs[j - 1].e_cpos);
                 *cpos = *cpos + ocfs2_rec_clusters(el,
                                &el->l_recs[j - 1]);
                 *cpos = *cpos - 1;
                 goto out;
             }
         }
 
         /*
          * If we got here, we never found a valid node where
          * the tree indicated one should be.
          */
         ocfs2_error(sb, "Invalid extent tree at extent block %llu\n",
                 (unsigned long long)blkno);
         ret = -EROFS;
         goto out;
 
 next_node:
         blkno = path->p_node[i].bh->b_blocknr;
         i--;
     }
 
 out:
     return ret;
 }
 
 /*
  * Extend the transaction by enough credits to complete the rotation,
  * and still leave at least the original number of credits allocated
  * to this transaction.
  */
 static int ocfs2_extend_rotate_transaction(handle_t *handle, int subtree_depth,
                        int op_credits,
                        struct ocfs2_path *path)
 {
     int ret = 0;
     int credits = (path->p_tree_depth - subtree_depth) * 2 + 1 + op_credits;
 
     if (jbd2_handle_buffer_credits(handle) < credits)
         ret = ocfs2_extend_trans(handle,
                 credits - jbd2_handle_buffer_credits(handle));
 
     return ret;
 }
 
 /*
  * Trap the case where we're inserting into the theoretical range past
  * the _actual_ left leaf range. Otherwise, we'll rotate a record
  * whose cpos is less than ours into the right leaf.
  *
  * It's only necessary to look at the rightmost record of the left
  * leaf because the logic that calls us should ensure that the
  * theoretical ranges in the path components above the leaves are
  * correct.
  */
 static int ocfs2_rotate_requires_path_adjustment(struct ocfs2_path *left_path,
                          u32 insert_cpos)
 {
     struct ocfs2_extent_list *left_el;
     struct ocfs2_extent_rec *rec;
     int next_free;
 
     left_el = path_leaf_el(left_path);
     next_free = le16_to_cpu(left_el->l_next_free_rec);
     rec = &left_el->l_recs[next_free - 1];
 
     if (insert_cpos > le32_to_cpu(rec->e_cpos))
         return 1;
     return 0;
 }
 
 static int ocfs2_leftmost_rec_contains(struct ocfs2_extent_list *el, u32 cpos)
 {
     int next_free = le16_to_cpu(el->l_next_free_rec);
     unsigned int range;
     struct ocfs2_extent_rec *rec;
 
     if (next_free == 0)
         return 0;
 
     rec = &el->l_recs[0];
     if (ocfs2_is_empty_extent(rec)) {
         /* Empty list. */
         if (next_free == 1)
             return 0;
         rec = &el->l_recs[1];
     }
 
     range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
     if (cpos >= le32_to_cpu(rec->e_cpos) && cpos < range)
         return 1;
     return 0;
 }
 
 /*
  * Rotate all the records in a btree right one record, starting at insert_cpos.
  *
  * The path to the rightmost leaf should be passed in.
  *
  * The array is assumed to be large enough to hold an entire path (tree depth).
  *
  * Upon successful return from this function:
  *
  * - The 'right_path' array will contain a path to the leaf block
  *   whose range contains e_cpos.
  * - That leaf block will have a single empty extent in list index 0.
  * - In the case that the rotation requires a post-insert update,
  *   *ret_left_path will contain a valid path which can be passed to
  *   ocfs2_insert_path().
  */
 static int ocfs2_rotate_tree_right(handle_t *handle,
                    struct ocfs2_extent_tree *et,
                    enum ocfs2_split_type split,
                    u32 insert_cpos,
                    struct ocfs2_path *right_path,
                    struct ocfs2_path **ret_left_path)
 {
     int ret, start, orig_credits = jbd2_handle_buffer_credits(handle);
     u32 cpos;
     struct ocfs2_path *left_path = NULL;
     struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
 
     *ret_left_path = NULL;
 
     left_path = ocfs2_new_path_from_path(right_path);
     if (!left_path) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_find_cpos_for_left_leaf(sb, right_path, &cpos);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     trace_ocfs2_rotate_tree_right(
         (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
         insert_cpos, cpos);
 
     /*
      * What we want to do here is:
      *
      * 1) Start with the rightmost path.
      *
      * 2) Determine a path to the leaf block directly to the left
      *    of that leaf.
      *
      * 3) Determine the 'subtree root' - the lowest level tree node
      *    which contains a path to both leaves.
      *
      * 4) Rotate the subtree.
      *
      * 5) Find the next subtree by considering the left path to be
      *    the new right path.
      *
      * The check at the top of this while loop also accepts
      * insert_cpos == cpos because cpos is only a _theoretical_
      * value to get us the left path - insert_cpos might very well
      * be filling that hole.
      *
      * Stop at a cpos of '0' because we either started at the
      * leftmost branch (i.e., a tree with one branch and a
      * rotation inside of it), or we've gone as far as we can in
      * rotating subtrees.
      */
     while (cpos && insert_cpos <= cpos) {
         trace_ocfs2_rotate_tree_right(
             (unsigned long long)
             ocfs2_metadata_cache_owner(et->et_ci),
             insert_cpos, cpos);
 
         ret = ocfs2_find_path(et->et_ci, left_path, cpos);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         mlog_bug_on_msg(path_leaf_bh(left_path) ==
                 path_leaf_bh(right_path),
                 "Owner %llu: error during insert of %u "
                 "(left path cpos %u) results in two identical "
                 "paths ending at %llu\n",
                 (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
                 insert_cpos, cpos,
                 (unsigned long long)
                 path_leaf_bh(left_path)->b_blocknr);
 
         if (split == SPLIT_NONE &&
             ocfs2_rotate_requires_path_adjustment(left_path,
                               insert_cpos)) {
 
             /*
              * We've rotated the tree as much as we
              * should. The rest is up to
              * ocfs2_insert_path() to complete, after the
              * record insertion. We indicate this
              * situation by returning the left path.
              *
              * The reason we don't adjust the records here
              * before the record insert is that an error
              * later might break the rule where a parent
              * record e_cpos will reflect the actual
              * e_cpos of the 1st nonempty record of the
              * child list.
              */
             *ret_left_path = left_path;
             goto out_ret_path;
         }
 
         start = ocfs2_find_subtree_root(et, left_path, right_path);
 
         trace_ocfs2_rotate_subtree(start,
             (unsigned long long)
             right_path->p_node[start].bh->b_blocknr,
             right_path->p_tree_depth);
 
         ret = ocfs2_extend_rotate_transaction(handle, start,
                               orig_credits, right_path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         ret = ocfs2_rotate_subtree_right(handle, et, left_path,
                          right_path, start);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         if (split != SPLIT_NONE &&
             ocfs2_leftmost_rec_contains(path_leaf_el(right_path),
                         insert_cpos)) {
             /*
              * A rotate moves the rightmost left leaf
              * record over to the leftmost right leaf
              * slot. If we're doing an extent split
              * instead of a real insert, then we have to
              * check that the extent to be split wasn't
              * just moved over. If it was, then we can
              * exit here, passing left_path back -
              * ocfs2_split_extent() is smart enough to
              * search both leaves.
              */
             *ret_left_path = left_path;
             goto out_ret_path;
         }
 
         /*
          * There is no need to re-read the next right path
          * as we know that it'll be our current left
          * path. Optimize by copying values instead.
          */
         ocfs2_mv_path(right_path, left_path);
 
         ret = ocfs2_find_cpos_for_left_leaf(sb, right_path, &cpos);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     }
 
 out:
     ocfs2_free_path(left_path);
 
 out_ret_path:
     return ret;
 }
 
 static int ocfs2_update_edge_lengths(handle_t *handle,
                      struct ocfs2_extent_tree *et,
                      struct ocfs2_path *path)
 {
     int i, idx, ret;
     struct ocfs2_extent_rec *rec;
     struct ocfs2_extent_list *el;
     struct ocfs2_extent_block *eb;
     u32 range;
 
     ret = ocfs2_journal_access_path(et->et_ci, handle, path);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     /* Path should always be rightmost. */
     eb = (struct ocfs2_extent_block *)path_leaf_bh(path)->b_data;
     BUG_ON(eb->h_next_leaf_blk != 0ULL);
 
     el = &eb->h_list;
     BUG_ON(le16_to_cpu(el->l_next_free_rec) == 0);
     idx = le16_to_cpu(el->l_next_free_rec) - 1;
     rec = &el->l_recs[idx];
     range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
 
     for (i = 0; i < path->p_tree_depth; i++) {
         el = path->p_node[i].el;
         idx = le16_to_cpu(el->l_next_free_rec) - 1;
         rec = &el->l_recs[idx];
 
         rec->e_int_clusters = cpu_to_le32(range);
         le32_add_cpu(&rec->e_int_clusters, -le32_to_cpu(rec->e_cpos));
 
         ocfs2_journal_dirty(handle, path->p_node[i].bh);
     }
 out:
     return ret;
 }
 
 static void ocfs2_unlink_path(handle_t *handle,
                   struct ocfs2_extent_tree *et,
                   struct ocfs2_cached_dealloc_ctxt *dealloc,
                   struct ocfs2_path *path, int unlink_start)
 {
     int ret, i;
     struct ocfs2_extent_block *eb;
     struct ocfs2_extent_list *el;
     struct buffer_head *bh;
 
     for(i = unlink_start; i < path_num_items(path); i++) {
         bh = path->p_node[i].bh;
 
         eb = (struct ocfs2_extent_block *)bh->b_data;
         /*
          * Not all nodes might have had their final count
          * decremented by the caller - handle this here.
          */
         el = &eb->h_list;
         if (le16_to_cpu(el->l_next_free_rec) > 1) {
             mlog(ML_ERROR,
                  "Inode %llu, attempted to remove extent block "
                  "%llu with %u records\n",
                  (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
                  (unsigned long long)le64_to_cpu(eb->h_blkno),
                  le16_to_cpu(el->l_next_free_rec));
 
             ocfs2_journal_dirty(handle, bh);
             ocfs2_remove_from_cache(et->et_ci, bh);
             continue;
         }
 
         el->l_next_free_rec = 0;
         memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
 
         ocfs2_journal_dirty(handle, bh);
 
         ret = ocfs2_cache_extent_block_free(dealloc, eb);
         if (ret)
             mlog_errno(ret);
 
         ocfs2_remove_from_cache(et->et_ci, bh);
     }
 }
 
 static void ocfs2_unlink_subtree(handle_t *handle,
                  struct ocfs2_extent_tree *et,
                  struct ocfs2_path *left_path,
                  struct ocfs2_path *right_path,
                  int subtree_index,
                  struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
     int i;
     struct buffer_head *root_bh = left_path->p_node[subtree_index].bh;
     struct ocfs2_extent_list *root_el = left_path->p_node[subtree_index].el;
     struct ocfs2_extent_block *eb;
 
     eb = (struct ocfs2_extent_block *)right_path->p_node[subtree_index + 1].bh->b_data;
 
     for(i = 1; i < le16_to_cpu(root_el->l_next_free_rec); i++)
         if (root_el->l_recs[i].e_blkno == eb->h_blkno)
             break;
 
     BUG_ON(i >= le16_to_cpu(root_el->l_next_free_rec));
 
     memset(&root_el->l_recs[i], 0, sizeof(struct ocfs2_extent_rec));
     le16_add_cpu(&root_el->l_next_free_rec, -1);
 
     eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
     eb->h_next_leaf_blk = 0;
 
     ocfs2_journal_dirty(handle, root_bh);
     ocfs2_journal_dirty(handle, path_leaf_bh(left_path));
 
     ocfs2_unlink_path(handle, et, dealloc, right_path,
               subtree_index + 1);
 }
 
 static int ocfs2_rotate_subtree_left(handle_t *handle,
                      struct ocfs2_extent_tree *et,
                      struct ocfs2_path *left_path,
                      struct ocfs2_path *right_path,
                      int subtree_index,
                      struct ocfs2_cached_dealloc_ctxt *dealloc,
                      int *deleted)
 {
     int ret, i, del_right_subtree = 0, right_has_empty = 0;
     struct buffer_head *root_bh, *et_root_bh = path_root_bh(right_path);
     struct ocfs2_extent_list *right_leaf_el, *left_leaf_el;
     struct ocfs2_extent_block *eb;
 
     *deleted = 0;
 
     right_leaf_el = path_leaf_el(right_path);
     left_leaf_el = path_leaf_el(left_path);
     root_bh = left_path->p_node[subtree_index].bh;
     BUG_ON(root_bh != right_path->p_node[subtree_index].bh);
 
     if (!ocfs2_is_empty_extent(&left_leaf_el->l_recs[0]))
         return 0;
 
     eb = (struct ocfs2_extent_block *)path_leaf_bh(right_path)->b_data;
     if (ocfs2_is_empty_extent(&right_leaf_el->l_recs[0])) {
         /*
          * It's legal for us to proceed if the right leaf is
          * the rightmost one and it has an empty extent. There
          * are two cases to handle - whether the leaf will be
          * empty after removal or not. If the leaf isn't empty
          * then just remove the empty extent up front. The
          * next block will handle empty leaves by flagging
          * them for unlink.
          *
          * Non rightmost leaves will throw -EAGAIN and the
          * caller can manually move the subtree and retry.
          */
 
         if (eb->h_next_leaf_blk != 0ULL)
             return -EAGAIN;
 
         if (le16_to_cpu(right_leaf_el->l_next_free_rec) > 1) {
             ret = ocfs2_journal_access_eb(handle, et->et_ci,
                               path_leaf_bh(right_path),
                               OCFS2_JOURNAL_ACCESS_WRITE);
             if (ret) {
                 mlog_errno(ret);
                 goto out;
             }
 
             ocfs2_remove_empty_extent(right_leaf_el);
         } else
             right_has_empty = 1;
     }
 
     if (eb->h_next_leaf_blk == 0ULL &&
         le16_to_cpu(right_leaf_el->l_next_free_rec) == 1) {
         /*
          * We have to update i_last_eb_blk during the meta
          * data delete.
          */
         ret = ocfs2_et_root_journal_access(handle, et,
                            OCFS2_JOURNAL_ACCESS_WRITE);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         del_right_subtree = 1;
     }
 
     /*
      * Getting here with an empty extent in the right path implies
      * that it's the rightmost path and will be deleted.
      */
     BUG_ON(right_has_empty && !del_right_subtree);
 
     ret = ocfs2_path_bh_journal_access(handle, et->et_ci, right_path,
                        subtree_index);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     for(i = subtree_index + 1; i < path_num_items(right_path); i++) {
         ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
                            right_path, i);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
                            left_path, i);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     if (!right_has_empty) {
         /*
          * Only do this if we're moving a real
          * record. Otherwise, the action is delayed until
          * after removal of the right path in which case we
          * can do a simple shift to remove the empty extent.
          */
         ocfs2_rotate_leaf(left_leaf_el, &right_leaf_el->l_recs[0]);
         memset(&right_leaf_el->l_recs[0], 0,
                sizeof(struct ocfs2_extent_rec));
     }
     if (eb->h_next_leaf_blk == 0ULL) {
         /*
          * Move recs over to get rid of empty extent, decrease
          * next_free. This is allowed to remove the last
          * extent in our leaf (setting l_next_free_rec to
          * zero) - the delete code below won't care.
          */
         ocfs2_remove_empty_extent(right_leaf_el);
     }
 
     ocfs2_journal_dirty(handle, path_leaf_bh(left_path));
     ocfs2_journal_dirty(handle, path_leaf_bh(right_path));
 
     if (del_right_subtree) {
         ocfs2_unlink_subtree(handle, et, left_path, right_path,
                      subtree_index, dealloc);
         ret = ocfs2_update_edge_lengths(handle, et, left_path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
         ocfs2_et_set_last_eb_blk(et, le64_to_cpu(eb->h_blkno));
 
         /*
          * Removal of the extent in the left leaf was skipped
          * above so we could delete the right path
          * 1st.
          */
         if (right_has_empty)
             ocfs2_remove_empty_extent(left_leaf_el);
 
         ocfs2_journal_dirty(handle, et_root_bh);
 
         *deleted = 1;
     } else
         ocfs2_complete_edge_insert(handle, left_path, right_path,
                        subtree_index);
 
 out:
     return ret;
 }
 
 /*
  * Given a full path, determine what cpos value would return us a path
  * containing the leaf immediately to the right of the current one.
  *
  * Will return zero if the path passed in is already the rightmost path.
  *
  * This looks similar, but is subtly different to
  * ocfs2_find_cpos_for_left_leaf().
  */
 int ocfs2_find_cpos_for_right_leaf(struct super_block *sb,
                    struct ocfs2_path *path, u32 *cpos)
 {
     int i, j, ret = 0;
     u64 blkno;
     struct ocfs2_extent_list *el;
 
     *cpos = 0;
 
     if (path->p_tree_depth == 0)
         return 0;
 
     blkno = path_leaf_bh(path)->b_blocknr;
 
     /* Start at the tree node just above the leaf and work our way up. */
     i = path->p_tree_depth - 1;
     while (i >= 0) {
         int next_free;
 
         el = path->p_node[i].el;
 
         /*
          * Find the extent record just after the one in our
          * path.
          */
         next_free = le16_to_cpu(el->l_next_free_rec);
         for(j = 0; j < le16_to_cpu(el->l_next_free_rec); j++) {
             if (le64_to_cpu(el->l_recs[j].e_blkno) == blkno) {
                 if (j == (next_free - 1)) {
                     if (i == 0) {
                         /*
                          * We've determined that the
                          * path specified is already
                          * the rightmost one - return a
                          * cpos of zero.
                          */
                         goto out;
                     }
                     /*
                      * The rightmost record points to our
                      * leaf - we need to travel up the
                      * tree one level.
                      */
                     goto next_node;
                 }
 
                 *cpos = le32_to_cpu(el->l_recs[j + 1].e_cpos);
                 goto out;
             }
         }
 
         /*
          * If we got here, we never found a valid node where
          * the tree indicated one should be.
          */
         ocfs2_error(sb, "Invalid extent tree at extent block %llu\n",
                 (unsigned long long)blkno);
         ret = -EROFS;
         goto out;
 
 next_node:
         blkno = path->p_node[i].bh->b_blocknr;
         i--;
     }
 
 out:
     return ret;
 }
 
 static int ocfs2_rotate_rightmost_leaf_left(handle_t *handle,
                         struct ocfs2_extent_tree *et,
                         struct ocfs2_path *path)
 {
     int ret;
     struct buffer_head *bh = path_leaf_bh(path);
     struct ocfs2_extent_list *el = path_leaf_el(path);
 
     if (!ocfs2_is_empty_extent(&el->l_recs[0]))
         return 0;
 
     ret = ocfs2_path_bh_journal_access(handle, et->et_ci, path,
                        path_num_items(path) - 1);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     ocfs2_remove_empty_extent(el);
     ocfs2_journal_dirty(handle, bh);
 
 out:
     return ret;
 }
 
 static int __ocfs2_rotate_tree_left(handle_t *handle,
                     struct ocfs2_extent_tree *et,
                     int orig_credits,
                     struct ocfs2_path *path,
                     struct ocfs2_cached_dealloc_ctxt *dealloc,
                     struct ocfs2_path **empty_extent_path)
 {
     int ret, subtree_root, deleted;
     u32 right_cpos;
     struct ocfs2_path *left_path = NULL;
     struct ocfs2_path *right_path = NULL;
     struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
 
     if (!ocfs2_is_empty_extent(&(path_leaf_el(path)->l_recs[0])))
         return 0;
 
     *empty_extent_path = NULL;
 
     ret = ocfs2_find_cpos_for_right_leaf(sb, path, &right_cpos);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     left_path = ocfs2_new_path_from_path(path);
     if (!left_path) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     ocfs2_cp_path(left_path, path);
 
     right_path = ocfs2_new_path_from_path(path);
     if (!right_path) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     while (right_cpos) {
         ret = ocfs2_find_path(et->et_ci, right_path, right_cpos);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         subtree_root = ocfs2_find_subtree_root(et, left_path,
                                right_path);
 
         trace_ocfs2_rotate_subtree(subtree_root,
              (unsigned long long)
              right_path->p_node[subtree_root].bh->b_blocknr,
              right_path->p_tree_depth);
 
         ret = ocfs2_extend_rotate_transaction(handle, 0,
                               orig_credits, left_path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         /*
          * Caller might still want to make changes to the
          * tree root, so re-add it to the journal here.
          */
         ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
                            left_path, 0);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         ret = ocfs2_rotate_subtree_left(handle, et, left_path,
                         right_path, subtree_root,
                         dealloc, &deleted);
         if (ret == -EAGAIN) {
             /*
              * The rotation has to temporarily stop due to
              * the right subtree having an empty
              * extent. Pass it back to the caller for a
              * fixup.
              */
             *empty_extent_path = right_path;
             right_path = NULL;
             goto out;
         }
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         /*
          * The subtree rotate might have removed records on
          * the rightmost edge. If so, then rotation is
          * complete.
          */
         if (deleted)
             break;
 
         ocfs2_mv_path(left_path, right_path);
 
         ret = ocfs2_find_cpos_for_right_leaf(sb, left_path,
                              &right_cpos);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     }
 
 out:
     ocfs2_free_path(right_path);
     ocfs2_free_path(left_path);
 
     return ret;
 }
 
 static int ocfs2_remove_rightmost_path(handle_t *handle,
                 struct ocfs2_extent_tree *et,
                 struct ocfs2_path *path,
                 struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
     int ret, subtree_index;
     u32 cpos;
     struct ocfs2_path *left_path = NULL;
     struct ocfs2_extent_block *eb;
     struct ocfs2_extent_list *el;
 
     ret = ocfs2_et_sanity_check(et);
     if (ret)
         goto out;
 
     ret = ocfs2_journal_access_path(et->et_ci, handle, path);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_find_cpos_for_left_leaf(ocfs2_metadata_cache_get_super(et->et_ci),
                         path, &cpos);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     if (cpos) {
         /*
          * We have a path to the left of this one - it needs
          * an update too.
          */
         left_path = ocfs2_new_path_from_path(path);
         if (!left_path) {
             ret = -ENOMEM;
             mlog_errno(ret);
             goto out;
         }
 
         ret = ocfs2_find_path(et->et_ci, left_path, cpos);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         ret = ocfs2_journal_access_path(et->et_ci, handle, left_path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         subtree_index = ocfs2_find_subtree_root(et, left_path, path);
 
         ocfs2_unlink_subtree(handle, et, left_path, path,
                      subtree_index, dealloc);
         ret = ocfs2_update_edge_lengths(handle, et, left_path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
         ocfs2_et_set_last_eb_blk(et, le64_to_cpu(eb->h_blkno));
     } else {
         /*
          * 'path' is also the leftmost path which
          * means it must be the only one. This gets
          * handled differently because we want to
          * revert the root back to having extents
          * in-line.
          */
         ocfs2_unlink_path(handle, et, dealloc, path, 1);
 
         el = et->et_root_el;
         el->l_tree_depth = 0;
         el->l_next_free_rec = 0;
         memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
 
         ocfs2_et_set_last_eb_blk(et, 0);
     }
 
     ocfs2_journal_dirty(handle, path_root_bh(path));
 
 out:
     ocfs2_free_path(left_path);
     return ret;
 }
 
 static int ocfs2_remove_rightmost_empty_extent(struct ocfs2_super *osb,
                 struct ocfs2_extent_tree *et,
                 struct ocfs2_path *path,
                 struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
     handle_t *handle;
     int ret;
     int credits = path->p_tree_depth * 2 + 1;
 
     handle = ocfs2_start_trans(osb, credits);
     if (IS_ERR(handle)) {
         ret = PTR_ERR(handle);
         mlog_errno(ret);
         return ret;
     }
 
     ret = ocfs2_remove_rightmost_path(handle, et, path, dealloc);
     if (ret)
         mlog_errno(ret);
 
     ocfs2_commit_trans(osb, handle);
     return ret;
 }
 
 /*
  * Left rotation of btree records.
  *
  * In many ways, this is (unsurprisingly) the opposite of right
  * rotation. We start at some non-rightmost path containing an empty
  * extent in the leaf block. The code works its way to the rightmost
  * path by rotating records to the left in every subtree.
  *
  * This is used by any code which reduces the number of extent records
  * in a leaf. After removal, an empty record should be placed in the
  * leftmost list position.
  *
  * This won't handle a length update of the rightmost path records if
  * the rightmost tree leaf record is removed so the caller is
  * responsible for detecting and correcting that.
  */
 static int ocfs2_rotate_tree_left(handle_t *handle,
                   struct ocfs2_extent_tree *et,
                   struct ocfs2_path *path,
                   struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
     int ret, orig_credits = jbd2_handle_buffer_credits(handle);
     struct ocfs2_path *tmp_path = NULL, *restart_path = NULL;
     struct ocfs2_extent_block *eb;
     struct ocfs2_extent_list *el;
 
     el = path_leaf_el(path);
     if (!ocfs2_is_empty_extent(&el->l_recs[0]))
         return 0;
 
     if (path->p_tree_depth == 0) {
 rightmost_no_delete:
         /*
          * Inline extents. This is trivially handled, so do
          * it up front.
          */
         ret = ocfs2_rotate_rightmost_leaf_left(handle, et, path);
         if (ret)
             mlog_errno(ret);
         goto out;
     }
 
     /*
      * Handle rightmost branch now. There's several cases:
      *  1) simple rotation leaving records in there. That's trivial.
      *  2) rotation requiring a branch delete - there's no more
      *     records left. Two cases of this:
      *     a) There are branches to the left.
      *     b) This is also the leftmost (the only) branch.
      *
      *  1) is handled via ocfs2_rotate_rightmost_leaf_left()
      *  2a) we need the left branch so that we can update it with the unlink
      *  2b) we need to bring the root back to inline extents.
      */
 
     eb = (struct ocfs2_extent_block *)path_leaf_bh(path)->b_data;
     el = &eb->h_list;
     if (eb->h_next_leaf_blk == 0) {
         /*
          * This gets a bit tricky if we're going to delete the
          * rightmost path. Get the other cases out of the way
          * 1st.
          */
         if (le16_to_cpu(el->l_next_free_rec) > 1)
             goto rightmost_no_delete;
 
         if (le16_to_cpu(el->l_next_free_rec) == 0) {
             ret = ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
                     "Owner %llu has empty extent block at %llu\n",
                     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
                     (unsigned long long)le64_to_cpu(eb->h_blkno));
             goto out;
         }
 
         /*
          * XXX: The caller can not trust "path" any more after
          * this as it will have been deleted. What do we do?
          *
          * In theory the rotate-for-merge code will never get
          * here because it'll always ask for a rotate in a
          * nonempty list.
          */
 
         ret = ocfs2_remove_rightmost_path(handle, et, path,
                           dealloc);
         if (ret)
             mlog_errno(ret);
         goto out;
     }
 
     /*
      * Now we can loop, remembering the path we get from -EAGAIN
      * and restarting from there.
      */
 try_rotate:
     ret = __ocfs2_rotate_tree_left(handle, et, orig_credits, path,
                        dealloc, &restart_path);
     if (ret && ret != -EAGAIN) {
         mlog_errno(ret);
         goto out;
     }
 
     while (ret == -EAGAIN) {
         tmp_path = restart_path;
         restart_path = NULL;
 
         ret = __ocfs2_rotate_tree_left(handle, et, orig_credits,
                            tmp_path, dealloc,
                            &restart_path);
         if (ret && ret != -EAGAIN) {
             mlog_errno(ret);
             goto out;
         }
 
         ocfs2_free_path(tmp_path);
         tmp_path = NULL;
 
         if (ret == 0)
             goto try_rotate;
     }
 
 out:
     ocfs2_free_path(tmp_path);
     ocfs2_free_path(restart_path);
     return ret;
 }
 
 static void ocfs2_cleanup_merge(struct ocfs2_extent_list *el,
                 int index)
 {
     struct ocfs2_extent_rec *rec = &el->l_recs[index];
     unsigned int size;
 
     if (rec->e_leaf_clusters == 0) {
         /*
          * We consumed all of the merged-from record. An empty
          * extent cannot exist anywhere but the 1st array
          * position, so move things over if the merged-from
          * record doesn't occupy that position.
          *
          * This creates a new empty extent so the caller
          * should be smart enough to have removed any existing
          * ones.
          */
         if (index > 0) {
             BUG_ON(ocfs2_is_empty_extent(&el->l_recs[0]));
             size = index * sizeof(struct ocfs2_extent_rec);
             memmove(&el->l_recs[1], &el->l_recs[0], size);
         }
 
         /*
          * Always memset - the caller doesn't check whether it
          * created an empty extent, so there could be junk in
          * the other fields.
          */
         memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
     }
 }
 
 static int ocfs2_get_right_path(struct ocfs2_extent_tree *et,
                 struct ocfs2_path *left_path,
                 struct ocfs2_path **ret_right_path)
 {
     int ret;
     u32 right_cpos;
     struct ocfs2_path *right_path = NULL;
     struct ocfs2_extent_list *left_el;
 
     *ret_right_path = NULL;
 
     /* This function shouldn't be called for non-trees. */
     BUG_ON(left_path->p_tree_depth == 0);
 
     left_el = path_leaf_el(left_path);
     BUG_ON(left_el->l_next_free_rec != left_el->l_count);
 
     ret = ocfs2_find_cpos_for_right_leaf(ocfs2_metadata_cache_get_super(et->et_ci),
                          left_path, &right_cpos);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     /* This function shouldn't be called for the rightmost leaf. */
     BUG_ON(right_cpos == 0);
 
     right_path = ocfs2_new_path_from_path(left_path);
     if (!right_path) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_find_path(et->et_ci, right_path, right_cpos);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     *ret_right_path = right_path;
 out:
     if (ret)
         ocfs2_free_path(right_path);
     return ret;
 }
 
 /*
  * Remove split_rec clusters from the record at index and merge them
  * onto the beginning of the record "next" to it.
  * For index < l_count - 1, the next means the extent rec at index + 1.
  * For index == l_count - 1, the "next" means the 1st extent rec of the
  * next extent block.
  */
 static int ocfs2_merge_rec_right(struct ocfs2_path *left_path,
                  handle_t *handle,
                  struct ocfs2_extent_tree *et,
                  struct ocfs2_extent_rec *split_rec,
                  int index)
 {
     int ret, next_free, i;
     unsigned int split_clusters = le16_to_cpu(split_rec->e_leaf_clusters);
     struct ocfs2_extent_rec *left_rec;
     struct ocfs2_extent_rec *right_rec;
     struct ocfs2_extent_list *right_el;
     struct ocfs2_path *right_path = NULL;
     int subtree_index = 0;
     struct ocfs2_extent_list *el = path_leaf_el(left_path);
     struct buffer_head *bh = path_leaf_bh(left_path);
     struct buffer_head *root_bh = NULL;
 
     BUG_ON(index >= le16_to_cpu(el->l_next_free_rec));
     left_rec = &el->l_recs[index];
 
     if (index == le16_to_cpu(el->l_next_free_rec) - 1 &&
         le16_to_cpu(el->l_next_free_rec) == le16_to_cpu(el->l_count)) {
         /* we meet with a cross extent block merge. */
         ret = ocfs2_get_right_path(et, left_path, &right_path);
         if (ret) {
             mlog_errno(ret);
             return ret;
         }
 
         right_el = path_leaf_el(right_path);
         next_free = le16_to_cpu(right_el->l_next_free_rec);
         BUG_ON(next_free <= 0);
         right_rec = &right_el->l_recs[0];
         if (ocfs2_is_empty_extent(right_rec)) {
             BUG_ON(next_free <= 1);
             right_rec = &right_el->l_recs[1];
         }
 
         BUG_ON(le32_to_cpu(left_rec->e_cpos) +
                le16_to_cpu(left_rec->e_leaf_clusters) !=
                le32_to_cpu(right_rec->e_cpos));
 
         subtree_index = ocfs2_find_subtree_root(et, left_path,
                             right_path);
 
         ret = ocfs2_extend_rotate_transaction(handle, subtree_index,
                     jbd2_handle_buffer_credits(handle),
                     right_path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         root_bh = left_path->p_node[subtree_index].bh;
         BUG_ON(root_bh != right_path->p_node[subtree_index].bh);
 
         ret = ocfs2_path_bh_journal_access(handle, et->et_ci, right_path,
                            subtree_index);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         for (i = subtree_index + 1;
              i < path_num_items(right_path); i++) {
             ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
                                right_path, i);
             if (ret) {
                 mlog_errno(ret);
                 goto out;
             }
 
             ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
                                left_path, i);
             if (ret) {
                 mlog_errno(ret);
                 goto out;
             }
         }
 
     } else {
         BUG_ON(index == le16_to_cpu(el->l_next_free_rec) - 1);
         right_rec = &el->l_recs[index + 1];
     }
 
     ret = ocfs2_path_bh_journal_access(handle, et->et_ci, left_path,
                        path_num_items(left_path) - 1);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     le16_add_cpu(&left_rec->e_leaf_clusters, -split_clusters);
 
     le32_add_cpu(&right_rec->e_cpos, -split_clusters);
     le64_add_cpu(&right_rec->e_blkno,
              -ocfs2_clusters_to_blocks(ocfs2_metadata_cache_get_super(et->et_ci),
                            split_clusters));
     le16_add_cpu(&right_rec->e_leaf_clusters, split_clusters);
 
     ocfs2_cleanup_merge(el, index);
 
     ocfs2_journal_dirty(handle, bh);
     if (right_path) {
         ocfs2_journal_dirty(handle, path_leaf_bh(right_path));
         ocfs2_complete_edge_insert(handle, left_path, right_path,
                        subtree_index);
     }
 out:
     ocfs2_free_path(right_path);
     return ret;
 }
 
 static int ocfs2_get_left_path(struct ocfs2_extent_tree *et,
                    struct ocfs2_path *right_path,
                    struct ocfs2_path **ret_left_path)
 {
     int ret;
     u32 left_cpos;
     struct ocfs2_path *left_path = NULL;
 
     *ret_left_path = NULL;
 
     /* This function shouldn't be called for non-trees. */
     BUG_ON(right_path->p_tree_depth == 0);
 
     ret = ocfs2_find_cpos_for_left_leaf(ocfs2_metadata_cache_get_super(et->et_ci),
                         right_path, &left_cpos);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     /* This function shouldn't be called for the leftmost leaf. */
     BUG_ON(left_cpos == 0);
 
     left_path = ocfs2_new_path_from_path(right_path);
     if (!left_path) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_find_path(et->et_ci, left_path, left_cpos);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     *ret_left_path = left_path;
 out:
     if (ret)
         ocfs2_free_path(left_path);
     return ret;
 }
 
 /*
  * Remove split_rec clusters from the record at index and merge them
  * onto the tail of the record "before" it.
  * For index > 0, the "before" means the extent rec at index - 1.
  *
  * For index == 0, the "before" means the last record of the previous
  * extent block. And there is also a situation that we may need to
  * remove the rightmost leaf extent block in the right_path and change
  * the right path to indicate the new rightmost path.
  */
 static int ocfs2_merge_rec_left(struct ocfs2_path *right_path,
                 handle_t *handle,
                 struct ocfs2_extent_tree *et,
                 struct ocfs2_extent_rec *split_rec,
                 struct ocfs2_cached_dealloc_ctxt *dealloc,
                 int index)
 {
     int ret, i, subtree_index = 0, has_empty_extent = 0;
     unsigned int split_clusters = le16_to_cpu(split_rec->e_leaf_clusters);
     struct ocfs2_extent_rec *left_rec;
     struct ocfs2_extent_rec *right_rec;
     struct ocfs2_extent_list *el = path_leaf_el(right_path);
     struct buffer_head *bh = path_leaf_bh(right_path);
     struct buffer_head *root_bh = NULL;
     struct ocfs2_path *left_path = NULL;
     struct ocfs2_extent_list *left_el;
 
     BUG_ON(index < 0);
 
     right_rec = &el->l_recs[index];
     if (index == 0) {
         /* we meet with a cross extent block merge. */
         ret = ocfs2_get_left_path(et, right_path, &left_path);
         if (ret) {
             mlog_errno(ret);
             return ret;
         }
 
         left_el = path_leaf_el(left_path);
         BUG_ON(le16_to_cpu(left_el->l_next_free_rec) !=
                le16_to_cpu(left_el->l_count));
 
         left_rec = &left_el->l_recs[
                 le16_to_cpu(left_el->l_next_free_rec) - 1];
         BUG_ON(le32_to_cpu(left_rec->e_cpos) +
                le16_to_cpu(left_rec->e_leaf_clusters) !=
                le32_to_cpu(split_rec->e_cpos));
 
         subtree_index = ocfs2_find_subtree_root(et, left_path,
                             right_path);
 
         ret = ocfs2_extend_rotate_transaction(handle, subtree_index,
                     jbd2_handle_buffer_credits(handle),
                     left_path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         root_bh = left_path->p_node[subtree_index].bh;
         BUG_ON(root_bh != right_path->p_node[subtree_index].bh);
 
         ret = ocfs2_path_bh_journal_access(handle, et->et_ci, right_path,
                            subtree_index);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         for (i = subtree_index + 1;
              i < path_num_items(right_path); i++) {
             ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
                                right_path, i);
             if (ret) {
                 mlog_errno(ret);
                 goto out;
             }
 
             ret = ocfs2_path_bh_journal_access(handle, et->et_ci,
                                left_path, i);
             if (ret) {
                 mlog_errno(ret);
                 goto out;
             }
         }
     } else {
         left_rec = &el->l_recs[index - 1];
         if (ocfs2_is_empty_extent(&el->l_recs[0]))
             has_empty_extent = 1;
     }
 
     ret = ocfs2_path_bh_journal_access(handle, et->et_ci, right_path,
                        path_num_items(right_path) - 1);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     if (has_empty_extent && index == 1) {
         /*
          * The easy case - we can just plop the record right in.
          */
         *left_rec = *split_rec;
     } else
         le16_add_cpu(&left_rec->e_leaf_clusters, split_clusters);
 
     le32_add_cpu(&right_rec->e_cpos, split_clusters);
     le64_add_cpu(&right_rec->e_blkno,
              ocfs2_clusters_to_blocks(ocfs2_metadata_cache_get_super(et->et_ci),
                           split_clusters));
     le16_add_cpu(&right_rec->e_leaf_clusters, -split_clusters);
 
     ocfs2_cleanup_merge(el, index);
 
     ocfs2_journal_dirty(handle, bh);
     if (left_path) {
         ocfs2_journal_dirty(handle, path_leaf_bh(left_path));
 
         /*
          * In the situation that the right_rec is empty and the extent
          * block is empty also,  ocfs2_complete_edge_insert can't handle
          * it and we need to delete the right extent block.
          */
         if (le16_to_cpu(right_rec->e_leaf_clusters) == 0 &&
             le16_to_cpu(el->l_next_free_rec) == 1) {
             /* extend credit for ocfs2_remove_rightmost_path */
             ret = ocfs2_extend_rotate_transaction(handle, 0,
                     jbd2_handle_buffer_credits(handle),
                     right_path);
             if (ret) {
                 mlog_errno(ret);
                 goto out;
             }
 
             ret = ocfs2_remove_rightmost_path(handle, et,
                               right_path,
                               dealloc);
             if (ret) {
                 mlog_errno(ret);
                 goto out;
             }
 
             /* Now the rightmost extent block has been deleted.
              * So we use the new rightmost path.
              */
             ocfs2_mv_path(right_path, left_path);
             left_path = NULL;
         } else
             ocfs2_complete_edge_insert(handle, left_path,
                            right_path, subtree_index);
     }
 out:
     ocfs2_free_path(left_path);
     return ret;
 }
 
 static int ocfs2_try_to_merge_extent(handle_t *handle,
                      struct ocfs2_extent_tree *et,
                      struct ocfs2_path *path,
                      int split_index,
                      struct ocfs2_extent_rec *split_rec,
                      struct ocfs2_cached_dealloc_ctxt *dealloc,
                      struct ocfs2_merge_ctxt *ctxt)
 {
     int ret = 0;
     struct ocfs2_extent_list *el = path_leaf_el(path);
     struct ocfs2_extent_rec *rec = &el->l_recs[split_index];
 
     BUG_ON(ctxt->c_contig_type == CONTIG_NONE);
 
     if (ctxt->c_split_covers_rec && ctxt->c_has_empty_extent) {
         /* extend credit for ocfs2_remove_rightmost_path */
         ret = ocfs2_extend_rotate_transaction(handle, 0,
                 jbd2_handle_buffer_credits(handle),
                 path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
         /*
          * The merge code will need to create an empty
          * extent to take the place of the newly
          * emptied slot. Remove any pre-existing empty
          * extents - having more than one in a leaf is
          * illegal.
          */
         ret = ocfs2_rotate_tree_left(handle, et, path, dealloc);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
         split_index--;
         rec = &el->l_recs[split_index];
     }
 
     if (ctxt->c_contig_type == CONTIG_LEFTRIGHT) {
         /*
          * Left-right contig implies this.
          */
         BUG_ON(!ctxt->c_split_covers_rec);
 
         /*
          * Since the leftright insert always covers the entire
          * extent, this call will delete the insert record
          * entirely, resulting in an empty extent record added to
          * the extent block.
          *
          * Since the adding of an empty extent shifts
          * everything back to the right, there's no need to
          * update split_index here.
          *
          * When the split_index is zero, we need to merge it to the
          * prevoius extent block. It is more efficient and easier
          * if we do merge_right first and merge_left later.
          */
         ret = ocfs2_merge_rec_right(path, handle, et, split_rec,
                         split_index);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         /*
          * We can only get this from logic error above.
          */
         BUG_ON(!ocfs2_is_empty_extent(&el->l_recs[0]));
 
         /* extend credit for ocfs2_remove_rightmost_path */
         ret = ocfs2_extend_rotate_transaction(handle, 0,
                     jbd2_handle_buffer_credits(handle),
                     path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         /* The merge left us with an empty extent, remove it. */
         ret = ocfs2_rotate_tree_left(handle, et, path, dealloc);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         rec = &el->l_recs[split_index];
 
         /*
          * Note that we don't pass split_rec here on purpose -
          * we've merged it into the rec already.
          */
         ret = ocfs2_merge_rec_left(path, handle, et, rec,
                        dealloc, split_index);
 
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         /* extend credit for ocfs2_remove_rightmost_path */
         ret = ocfs2_extend_rotate_transaction(handle, 0,
                 jbd2_handle_buffer_credits(handle),
                 path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         ret = ocfs2_rotate_tree_left(handle, et, path, dealloc);
         /*
          * Error from this last rotate is not critical, so
          * print but don't bubble it up.
          */
         if (ret)
             mlog_errno(ret);
         ret = 0;
     } else {
         /*
          * Merge a record to the left or right.
          *
          * 'contig_type' is relative to the existing record,
          * so for example, if we're "right contig", it's to
          * the record on the left (hence the left merge).
          */
         if (ctxt->c_contig_type == CONTIG_RIGHT) {
             ret = ocfs2_merge_rec_left(path, handle, et,
                            split_rec, dealloc,
                            split_index);
             if (ret) {
                 mlog_errno(ret);
                 goto out;
             }
         } else {
             ret = ocfs2_merge_rec_right(path, handle,
                             et, split_rec,
                             split_index);
             if (ret) {
                 mlog_errno(ret);
                 goto out;
             }
         }
 
         if (ctxt->c_split_covers_rec) {
             /* extend credit for ocfs2_remove_rightmost_path */
             ret = ocfs2_extend_rotate_transaction(handle, 0,
                     jbd2_handle_buffer_credits(handle),
                     path);
             if (ret) {
                 mlog_errno(ret);
                 ret = 0;
                 goto out;
             }
 
             /*
              * The merge may have left an empty extent in
              * our leaf. Try to rotate it away.
              */
             ret = ocfs2_rotate_tree_left(handle, et, path,
                              dealloc);
             if (ret)
                 mlog_errno(ret);
             ret = 0;
         }
     }
 
 out:
     return ret;
 }
 
 static void ocfs2_subtract_from_rec(struct super_block *sb,
                     enum ocfs2_split_type split,
                     struct ocfs2_extent_rec *rec,
                     struct ocfs2_extent_rec *split_rec)
 {
     u64 len_blocks;
 
     len_blocks = ocfs2_clusters_to_blocks(sb,
                 le16_to_cpu(split_rec->e_leaf_clusters));
 
     if (split == SPLIT_LEFT) {
         /*
          * Region is on the left edge of the existing
          * record.
          */
         le32_add_cpu(&rec->e_cpos,
                  le16_to_cpu(split_rec->e_leaf_clusters));
         le64_add_cpu(&rec->e_blkno, len_blocks);
         le16_add_cpu(&rec->e_leaf_clusters,
                  -le16_to_cpu(split_rec->e_leaf_clusters));
     } else {
         /*
          * Region is on the right edge of the existing
          * record.
          */
         le16_add_cpu(&rec->e_leaf_clusters,
                  -le16_to_cpu(split_rec->e_leaf_clusters));
     }
 }
 
 /*
  * Do the final bits of extent record insertion at the target leaf
  * list. If this leaf is part of an allocation tree, it is assumed
  * that the tree above has been prepared.
  */
 static void ocfs2_insert_at_leaf(struct ocfs2_extent_tree *et,
                  struct ocfs2_extent_rec *insert_rec,
                  struct ocfs2_extent_list *el,
                  struct ocfs2_insert_type *insert)
 {
     int i = insert->ins_contig_index;
     unsigned int range;
     struct ocfs2_extent_rec *rec;
 
     BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
 
     if (insert->ins_split != SPLIT_NONE) {
         i = ocfs2_search_extent_list(el, le32_to_cpu(insert_rec->e_cpos));
         BUG_ON(i == -1);
         rec = &el->l_recs[i];
         ocfs2_subtract_from_rec(ocfs2_metadata_cache_get_super(et->et_ci),
                     insert->ins_split, rec,
                     insert_rec);
         goto rotate;
     }
 
     /*
      * Contiguous insert - either left or right.
      */
     if (insert->ins_contig != CONTIG_NONE) {
         rec = &el->l_recs[i];
         if (insert->ins_contig == CONTIG_LEFT) {
             rec->e_blkno = insert_rec->e_blkno;
             rec->e_cpos = insert_rec->e_cpos;
         }
         le16_add_cpu(&rec->e_leaf_clusters,
                  le16_to_cpu(insert_rec->e_leaf_clusters));
         return;
     }
 
     /*
      * Handle insert into an empty leaf.
      */
     if (le16_to_cpu(el->l_next_free_rec) == 0 ||
         ((le16_to_cpu(el->l_next_free_rec) == 1) &&
          ocfs2_is_empty_extent(&el->l_recs[0]))) {
         el->l_recs[0] = *insert_rec;
         el->l_next_free_rec = cpu_to_le16(1);
         return;
     }
 
     /*
      * Appending insert.
      */
     if (insert->ins_appending == APPEND_TAIL) {
         i = le16_to_cpu(el->l_next_free_rec) - 1;
         rec = &el->l_recs[i];
         range = le32_to_cpu(rec->e_cpos)
             + le16_to_cpu(rec->e_leaf_clusters);
         BUG_ON(le32_to_cpu(insert_rec->e_cpos) < range);
 
         mlog_bug_on_msg(le16_to_cpu(el->l_next_free_rec) >=
                 le16_to_cpu(el->l_count),
                 "owner %llu, depth %u, count %u, next free %u, "
                 "rec.cpos %u, rec.clusters %u, "
                 "insert.cpos %u, insert.clusters %u\n",
                 ocfs2_metadata_cache_owner(et->et_ci),
                 le16_to_cpu(el->l_tree_depth),
                 le16_to_cpu(el->l_count),
                 le16_to_cpu(el->l_next_free_rec),
                 le32_to_cpu(el->l_recs[i].e_cpos),
                 le16_to_cpu(el->l_recs[i].e_leaf_clusters),
                 le32_to_cpu(insert_rec->e_cpos),
                 le16_to_cpu(insert_rec->e_leaf_clusters));
         i++;
         el->l_recs[i] = *insert_rec;
         le16_add_cpu(&el->l_next_free_rec, 1);
         return;
     }
 
 rotate:
     /*
      * Ok, we have to rotate.
      *
      * At this point, it is safe to assume that inserting into an
      * empty leaf and appending to a leaf have both been handled
      * above.
      *
      * This leaf needs to have space, either by the empty 1st
      * extent record, or by virtue of an l_next_free_rec < l_count.
      */
     ocfs2_rotate_leaf(el, insert_rec);
 }
 
 static void ocfs2_adjust_rightmost_records(handle_t *handle,
                        struct ocfs2_extent_tree *et,
                        struct ocfs2_path *path,
                        struct ocfs2_extent_rec *insert_rec)
 {
     int i, next_free;
     struct buffer_head *bh;
     struct ocfs2_extent_list *el;
     struct ocfs2_extent_rec *rec;
 
     /*
      * Update everything except the leaf block.
      */
     for (i = 0; i < path->p_tree_depth; i++) {
         bh = path->p_node[i].bh;
         el = path->p_node[i].el;
 
         next_free = le16_to_cpu(el->l_next_free_rec);
         if (next_free == 0) {
             ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
                     "Owner %llu has a bad extent list\n",
                     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci));
             return;
         }
 
         rec = &el->l_recs[next_free - 1];
 
         rec->e_int_clusters = insert_rec->e_cpos;
         le32_add_cpu(&rec->e_int_clusters,
                  le16_to_cpu(insert_rec->e_leaf_clusters));
         le32_add_cpu(&rec->e_int_clusters,
                  -le32_to_cpu(rec->e_cpos));
 
         ocfs2_journal_dirty(handle, bh);
     }
 }
 
 static int ocfs2_append_rec_to_path(handle_t *handle,
                     struct ocfs2_extent_tree *et,
                     struct ocfs2_extent_rec *insert_rec,
                     struct ocfs2_path *right_path,
                     struct ocfs2_path **ret_left_path)
 {
     int ret, next_free;
     struct ocfs2_extent_list *el;
     struct ocfs2_path *left_path = NULL;
 
     *ret_left_path = NULL;
 
     /*
      * This shouldn't happen for non-trees. The extent rec cluster
      * count manipulation below only works for interior nodes.
      */
     BUG_ON(right_path->p_tree_depth == 0);
 
     /*
      * If our appending insert is at the leftmost edge of a leaf,
      * then we might need to update the rightmost records of the
      * neighboring path.
      */
     el = path_leaf_el(right_path);
     next_free = le16_to_cpu(el->l_next_free_rec);
     if (next_free == 0 ||
         (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0]))) {
         u32 left_cpos;
 
         ret = ocfs2_find_cpos_for_left_leaf(ocfs2_metadata_cache_get_super(et->et_ci),
                             right_path, &left_cpos);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         trace_ocfs2_append_rec_to_path(
             (unsigned long long)
             ocfs2_metadata_cache_owner(et->et_ci),
             le32_to_cpu(insert_rec->e_cpos),
             left_cpos);
 
         /*
          * No need to worry if the append is already in the
          * leftmost leaf.
          */
         if (left_cpos) {
             left_path = ocfs2_new_path_from_path(right_path);
             if (!left_path) {
                 ret = -ENOMEM;
                 mlog_errno(ret);
                 goto out;
             }
 
             ret = ocfs2_find_path(et->et_ci, left_path,
                           left_cpos);
             if (ret) {
                 mlog_errno(ret);
                 goto out;
             }
 
             /*
              * ocfs2_insert_path() will pass the left_path to the
              * journal for us.
              */
         }
     }
 
     ret = ocfs2_journal_access_path(et->et_ci, handle, right_path);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     ocfs2_adjust_rightmost_records(handle, et, right_path, insert_rec);
 
     *ret_left_path = left_path;
     ret = 0;
 out:
     if (ret != 0)
         ocfs2_free_path(left_path);
 
     return ret;
 }
 
 static void ocfs2_split_record(struct ocfs2_extent_tree *et,
                    struct ocfs2_path *left_path,
                    struct ocfs2_path *right_path,
                    struct ocfs2_extent_rec *split_rec,
                    enum ocfs2_split_type split)
 {
     int index;
     u32 cpos = le32_to_cpu(split_rec->e_cpos);
     struct ocfs2_extent_list *left_el = NULL, *right_el, *insert_el, *el;
     struct ocfs2_extent_rec *rec, *tmprec;
 
     right_el = path_leaf_el(right_path);
     if (left_path)
         left_el = path_leaf_el(left_path);
 
     el = right_el;
     insert_el = right_el;
     index = ocfs2_search_extent_list(el, cpos);
     if (index != -1) {
         if (index == 0 && left_path) {
             BUG_ON(ocfs2_is_empty_extent(&el->l_recs[0]));
 
             /*
              * This typically means that the record
              * started in the left path but moved to the
              * right as a result of rotation. We either
              * move the existing record to the left, or we
              * do the later insert there.
              *
              * In this case, the left path should always
              * exist as the rotate code will have passed
              * it back for a post-insert update.
              */
 
             if (split == SPLIT_LEFT) {
                 /*
                  * It's a left split. Since we know
                  * that the rotate code gave us an
                  * empty extent in the left path, we
                  * can just do the insert there.
                  */
                 insert_el = left_el;
             } else {
                 /*
                  * Right split - we have to move the
                  * existing record over to the left
                  * leaf. The insert will be into the
                  * newly created empty extent in the
                  * right leaf.
                  */
                 tmprec = &right_el->l_recs[index];
                 ocfs2_rotate_leaf(left_el, tmprec);
                 el = left_el;
 
                 memset(tmprec, 0, sizeof(*tmprec));
                 index = ocfs2_search_extent_list(left_el, cpos);
                 BUG_ON(index == -1);
             }
         }
     } else {
         BUG_ON(!left_path);
         BUG_ON(!ocfs2_is_empty_extent(&left_el->l_recs[0]));
         /*
          * Left path is easy - we can just allow the insert to
          * happen.
          */
         el = left_el;
         insert_el = left_el;
         index = ocfs2_search_extent_list(el, cpos);
         BUG_ON(index == -1);
     }
 
     rec = &el->l_recs[index];
     ocfs2_subtract_from_rec(ocfs2_metadata_cache_get_super(et->et_ci),
                 split, rec, split_rec);
     ocfs2_rotate_leaf(insert_el, split_rec);
 }
 
 /*
  * This function only does inserts on an allocation b-tree. For tree
  * depth = 0, ocfs2_insert_at_leaf() is called directly.
  *
  * right_path is the path we want to do the actual insert
  * in. left_path should only be passed in if we need to update that
  * portion of the tree after an edge insert.
  */
 static int ocfs2_insert_path(handle_t *handle,
                  struct ocfs2_extent_tree *et,
                  struct ocfs2_path *left_path,
                  struct ocfs2_path *right_path,
                  struct ocfs2_extent_rec *insert_rec,
                  struct ocfs2_insert_type *insert)
 {
     int ret, subtree_index;
     struct buffer_head *leaf_bh = path_leaf_bh(right_path);
 
     if (left_path) {
         /*
          * There's a chance that left_path got passed back to
          * us without being accounted for in the
          * journal. Extend our transaction here to be sure we
          * can change those blocks.
          */
         ret = ocfs2_extend_trans(handle, left_path->p_tree_depth);
         if (ret < 0) {
             mlog_errno(ret);
             goto out;
         }
 
         ret = ocfs2_journal_access_path(et->et_ci, handle, left_path);
         if (ret < 0) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     /*
      * Pass both paths to the journal. The majority of inserts
      * will be touching all components anyway.
      */
     ret = ocfs2_journal_access_path(et->et_ci, handle, right_path);
     if (ret < 0) {
         mlog_errno(ret);
         goto out;
     }
 
     if (insert->ins_split != SPLIT_NONE) {
         /*
          * We could call ocfs2_insert_at_leaf() for some types
          * of splits, but it's easier to just let one separate
          * function sort it all out.
          */
         ocfs2_split_record(et, left_path, right_path,
                    insert_rec, insert->ins_split);
 
         /*
          * Split might have modified either leaf and we don't
          * have a guarantee that the later edge insert will
          * dirty this for us.
          */
         if (left_path)
             ocfs2_journal_dirty(handle,
                         path_leaf_bh(left_path));
     } else
         ocfs2_insert_at_leaf(et, insert_rec, path_leaf_el(right_path),
                      insert);
 
     ocfs2_journal_dirty(handle, leaf_bh);
 
     if (left_path) {
         /*
          * The rotate code has indicated that we need to fix
          * up portions of the tree after the insert.
          *
          * XXX: Should we extend the transaction here?
          */
         subtree_index = ocfs2_find_subtree_root(et, left_path,
                             right_path);
         ocfs2_complete_edge_insert(handle, left_path, right_path,
                        subtree_index);
     }
 
     ret = 0;
 out:
     return ret;
 }
 
 static int ocfs2_do_insert_extent(handle_t *handle,
                   struct ocfs2_extent_tree *et,
                   struct ocfs2_extent_rec *insert_rec,
                   struct ocfs2_insert_type *type)
 {
     int ret, rotate = 0;
     u32 cpos;
     struct ocfs2_path *right_path = NULL;
     struct ocfs2_path *left_path = NULL;
     struct ocfs2_extent_list *el;
 
     el = et->et_root_el;
 
     ret = ocfs2_et_root_journal_access(handle, et,
                        OCFS2_JOURNAL_ACCESS_WRITE);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     if (le16_to_cpu(el->l_tree_depth) == 0) {
         ocfs2_insert_at_leaf(et, insert_rec, el, type);
         goto out_update_clusters;
     }
 
     right_path = ocfs2_new_path_from_et(et);
     if (!right_path) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     /*
      * Determine the path to start with. Rotations need the
      * rightmost path, everything else can go directly to the
      * target leaf.
      */
     cpos = le32_to_cpu(insert_rec->e_cpos);
     if (type->ins_appending == APPEND_NONE &&
         type->ins_contig == CONTIG_NONE) {
         rotate = 1;
         cpos = UINT_MAX;
     }
 
     ret = ocfs2_find_path(et->et_ci, right_path, cpos);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     /*
      * Rotations and appends need special treatment - they modify
      * parts of the tree's above them.
      *
      * Both might pass back a path immediate to the left of the
      * one being inserted to. This will be cause
      * ocfs2_insert_path() to modify the rightmost records of
      * left_path to account for an edge insert.
      *
      * XXX: When modifying this code, keep in mind that an insert
      * can wind up skipping both of these two special cases...
      */
     if (rotate) {
         ret = ocfs2_rotate_tree_right(handle, et, type->ins_split,
                           le32_to_cpu(insert_rec->e_cpos),
                           right_path, &left_path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         /*
          * ocfs2_rotate_tree_right() might have extended the
          * transaction without re-journaling our tree root.
          */
         ret = ocfs2_et_root_journal_access(handle, et,
                            OCFS2_JOURNAL_ACCESS_WRITE);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     } else if (type->ins_appending == APPEND_TAIL
            && type->ins_contig != CONTIG_LEFT) {
         ret = ocfs2_append_rec_to_path(handle, et, insert_rec,
                            right_path, &left_path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     ret = ocfs2_insert_path(handle, et, left_path, right_path,
                 insert_rec, type);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
 out_update_clusters:
     if (type->ins_split == SPLIT_NONE)
         ocfs2_et_update_clusters(et,
                      le16_to_cpu(insert_rec->e_leaf_clusters));
 
     ocfs2_journal_dirty(handle, et->et_root_bh);
 
 out:
     ocfs2_free_path(left_path);
     ocfs2_free_path(right_path);
 
     return ret;
 }
 
 static int ocfs2_figure_merge_contig_type(struct ocfs2_extent_tree *et,
                    struct ocfs2_path *path,
                    struct ocfs2_extent_list *el, int index,
                    struct ocfs2_extent_rec *split_rec,
                    struct ocfs2_merge_ctxt *ctxt)
 {
     int status = 0;
     enum ocfs2_contig_type ret = CONTIG_NONE;
     u32 left_cpos, right_cpos;
     struct ocfs2_extent_rec *rec = NULL;
     struct ocfs2_extent_list *new_el;
     struct ocfs2_path *left_path = NULL, *right_path = NULL;
     struct buffer_head *bh;
     struct ocfs2_extent_block *eb;
     struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
 
     if (index > 0) {
         rec = &el->l_recs[index - 1];
     } else if (path->p_tree_depth > 0) {
         status = ocfs2_find_cpos_for_left_leaf(sb, path, &left_cpos);
         if (status)
             goto exit;
 
         if (left_cpos != 0) {
             left_path = ocfs2_new_path_from_path(path);
             if (!left_path) {
                 status = -ENOMEM;
                 mlog_errno(status);
                 goto exit;
             }
 
             status = ocfs2_find_path(et->et_ci, left_path,
                          left_cpos);
             if (status)
                 goto free_left_path;
 
             new_el = path_leaf_el(left_path);
 
             if (le16_to_cpu(new_el->l_next_free_rec) !=
                 le16_to_cpu(new_el->l_count)) {
                 bh = path_leaf_bh(left_path);
                 eb = (struct ocfs2_extent_block *)bh->b_data;
                 status = ocfs2_error(sb,
                         "Extent block #%llu has an invalid l_next_free_rec of %d.  It should have matched the l_count of %d\n",
                         (unsigned long long)le64_to_cpu(eb->h_blkno),
                         le16_to_cpu(new_el->l_next_free_rec),
                         le16_to_cpu(new_el->l_count));
                 goto free_left_path;
             }
             rec = &new_el->l_recs[
                 le16_to_cpu(new_el->l_next_free_rec) - 1];
         }
     }
 
     /*
      * We're careful to check for an empty extent record here -
      * the merge code will know what to do if it sees one.
      */
     if (rec) {
         if (index == 1 && ocfs2_is_empty_extent(rec)) {
             if (split_rec->e_cpos == el->l_recs[index].e_cpos)
                 ret = CONTIG_RIGHT;
         } else {
             ret = ocfs2_et_extent_contig(et, rec, split_rec);
         }
     }
 
     rec = NULL;
     if (index < (le16_to_cpu(el->l_next_free_rec) - 1))
         rec = &el->l_recs[index + 1];
     else if (le16_to_cpu(el->l_next_free_rec) == le16_to_cpu(el->l_count) &&
          path->p_tree_depth > 0) {
         status = ocfs2_find_cpos_for_right_leaf(sb, path, &right_cpos);
         if (status)
             goto free_left_path;
 
         if (right_cpos == 0)
             goto free_left_path;
 
         right_path = ocfs2_new_path_from_path(path);
         if (!right_path) {
             status = -ENOMEM;
             mlog_errno(status);
             goto free_left_path;
         }
 
         status = ocfs2_find_path(et->et_ci, right_path, right_cpos);
         if (status)
             goto free_right_path;
 
         new_el = path_leaf_el(right_path);
         rec = &new_el->l_recs[0];
         if (ocfs2_is_empty_extent(rec)) {
             if (le16_to_cpu(new_el->l_next_free_rec) <= 1) {
                 bh = path_leaf_bh(right_path);
                 eb = (struct ocfs2_extent_block *)bh->b_data;
                 status = ocfs2_error(sb,
                         "Extent block #%llu has an invalid l_next_free_rec of %d\n",
                         (unsigned long long)le64_to_cpu(eb->h_blkno),
                         le16_to_cpu(new_el->l_next_free_rec));
                 goto free_right_path;
             }
             rec = &new_el->l_recs[1];
         }
     }
 
     if (rec) {
         enum ocfs2_contig_type contig_type;
 
         contig_type = ocfs2_et_extent_contig(et, rec, split_rec);
 
         if (contig_type == CONTIG_LEFT && ret == CONTIG_RIGHT)
             ret = CONTIG_LEFTRIGHT;
         else if (ret == CONTIG_NONE)
             ret = contig_type;
     }
 
 free_right_path:
     ocfs2_free_path(right_path);
 free_left_path:
     ocfs2_free_path(left_path);
 exit:
     if (status == 0)
         ctxt->c_contig_type = ret;
 
     return status;
 }
 
 static void ocfs2_figure_contig_type(struct ocfs2_extent_tree *et,
                      struct ocfs2_insert_type *insert,
                      struct ocfs2_extent_list *el,
                      struct ocfs2_extent_rec *insert_rec)
 {
     int i;
     enum ocfs2_contig_type contig_type = CONTIG_NONE;
 
     BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
 
     for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
         contig_type = ocfs2_et_extent_contig(et, &el->l_recs[i],
                              insert_rec);
         if (contig_type != CONTIG_NONE) {
             insert->ins_contig_index = i;
             break;
         }
     }
     insert->ins_contig = contig_type;
 
     if (insert->ins_contig != CONTIG_NONE) {
         struct ocfs2_extent_rec *rec =
                 &el->l_recs[insert->ins_contig_index];
         unsigned int len = le16_to_cpu(rec->e_leaf_clusters) +
                    le16_to_cpu(insert_rec->e_leaf_clusters);
 
         /*
          * Caller might want us to limit the size of extents, don't
          * calculate contiguousness if we might exceed that limit.
          */
         if (et->et_max_leaf_clusters &&
             (len > et->et_max_leaf_clusters))
             insert->ins_contig = CONTIG_NONE;
     }
 }
 
 /*
  * This should only be called against the righmost leaf extent list.
  *
  * ocfs2_figure_appending_type() will figure out whether we'll have to
  * insert at the tail of the rightmost leaf.
  *
  * This should also work against the root extent list for tree's with 0
  * depth. If we consider the root extent list to be the rightmost leaf node
  * then the logic here makes sense.
  */
 static void ocfs2_figure_appending_type(struct ocfs2_insert_type *insert,
                     struct ocfs2_extent_list *el,
                     struct ocfs2_extent_rec *insert_rec)
 {
     int i;
     u32 cpos = le32_to_cpu(insert_rec->e_cpos);
     struct ocfs2_extent_rec *rec;
 
     insert->ins_appending = APPEND_NONE;
 
     BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
 
     if (!el->l_next_free_rec)
         goto set_tail_append;
 
     if (ocfs2_is_empty_extent(&el->l_recs[0])) {
         /* Were all records empty? */
         if (le16_to_cpu(el->l_next_free_rec) == 1)
             goto set_tail_append;
     }
 
     i = le16_to_cpu(el->l_next_free_rec) - 1;
     rec = &el->l_recs[i];
 
     if (cpos >=
         (le32_to_cpu(rec->e_cpos) + le16_to_cpu(rec->e_leaf_clusters)))
         goto set_tail_append;
 
     return;
 
 set_tail_append:
     insert->ins_appending = APPEND_TAIL;
 }
 
 /*
  * Helper function called at the beginning of an insert.
  *
  * This computes a few things that are commonly used in the process of
  * inserting into the btree:
  *   - Whether the new extent is contiguous with an existing one.
  *   - The current tree depth.
  *   - Whether the insert is an appending one.
  *   - The total # of free records in the tree.
  *
  * All of the information is stored on the ocfs2_insert_type
  * structure.
  */
 static int ocfs2_figure_insert_type(struct ocfs2_extent_tree *et,
                     struct buffer_head **last_eb_bh,
                     struct ocfs2_extent_rec *insert_rec,
                     int *free_records,
                     struct ocfs2_insert_type *insert)
 {
     int ret;
     struct ocfs2_extent_block *eb;
     struct ocfs2_extent_list *el;
     struct ocfs2_path *path = NULL;
     struct buffer_head *bh = NULL;
 
     insert->ins_split = SPLIT_NONE;
 
     el = et->et_root_el;
     insert->ins_tree_depth = le16_to_cpu(el->l_tree_depth);
 
     if (el->l_tree_depth) {
         /*
          * If we have tree depth, we read in the
          * rightmost extent block ahead of time as
          * ocfs2_figure_insert_type() and ocfs2_add_branch()
          * may want it later.
          */
         ret = ocfs2_read_extent_block(et->et_ci,
                           ocfs2_et_get_last_eb_blk(et),
                           &bh);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
         eb = (struct ocfs2_extent_block *) bh->b_data;
         el = &eb->h_list;
     }
 
     /*
      * Unless we have a contiguous insert, we'll need to know if
      * there is room left in our allocation tree for another
      * extent record.
      *
      * XXX: This test is simplistic, we can search for empty
      * extent records too.
      */
     *free_records = le16_to_cpu(el->l_count) -
         le16_to_cpu(el->l_next_free_rec);
 
     if (!insert->ins_tree_depth) {
         ocfs2_figure_contig_type(et, insert, el, insert_rec);
         ocfs2_figure_appending_type(insert, el, insert_rec);
         return 0;
     }
 
     path = ocfs2_new_path_from_et(et);
     if (!path) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     /*
      * In the case that we're inserting past what the tree
      * currently accounts for, ocfs2_find_path() will return for
      * us the rightmost tree path. This is accounted for below in
      * the appending code.
      */
     ret = ocfs2_find_path(et->et_ci, path, le32_to_cpu(insert_rec->e_cpos));
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     el = path_leaf_el(path);
 
     /*
      * Now that we have the path, there's two things we want to determine:
      * 1) Contiguousness (also set contig_index if this is so)
      *
      * 2) Are we doing an append? We can trivially break this up
          *     into two types of appends: simple record append, or a
          *     rotate inside the tail leaf.
      */
     ocfs2_figure_contig_type(et, insert, el, insert_rec);
 
     /*
      * The insert code isn't quite ready to deal with all cases of
      * left contiguousness. Specifically, if it's an insert into
      * the 1st record in a leaf, it will require the adjustment of
      * cluster count on the last record of the path directly to it's
      * left. For now, just catch that case and fool the layers
      * above us. This works just fine for tree_depth == 0, which
      * is why we allow that above.
      */
     if (insert->ins_contig == CONTIG_LEFT &&
         insert->ins_contig_index == 0)
         insert->ins_contig = CONTIG_NONE;
 
     /*
      * Ok, so we can simply compare against last_eb to figure out
      * whether the path doesn't exist. This will only happen in
      * the case that we're doing a tail append, so maybe we can
      * take advantage of that information somehow.
      */
     if (ocfs2_et_get_last_eb_blk(et) ==
         path_leaf_bh(path)->b_blocknr) {
         /*
          * Ok, ocfs2_find_path() returned us the rightmost
          * tree path. This might be an appending insert. There are
          * two cases:
          *    1) We're doing a true append at the tail:
          *  -This might even be off the end of the leaf
          *    2) We're "appending" by rotating in the tail
          */
         ocfs2_figure_appending_type(insert, el, insert_rec);
     }
 
 out:
     ocfs2_free_path(path);
 
     if (ret == 0)
         *last_eb_bh = bh;
     else
         brelse(bh);
     return ret;
 }
 
 /*
  * Insert an extent into a btree.
  *
  * The caller needs to update the owning btree's cluster count.
  */
 int ocfs2_insert_extent(handle_t *handle,
             struct ocfs2_extent_tree *et,
             u32 cpos,
             u64 start_blk,
             u32 new_clusters,
             u8 flags,
             struct ocfs2_alloc_context *meta_ac)
 {
     int status;
     int free_records;
     struct buffer_head *last_eb_bh = NULL;
     struct ocfs2_insert_type insert = {0, };
     struct ocfs2_extent_rec rec;
 
     trace_ocfs2_insert_extent_start(
         (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
         cpos, new_clusters);
 
     memset(&rec, 0, sizeof(rec));
     rec.e_cpos = cpu_to_le32(cpos);
     rec.e_blkno = cpu_to_le64(start_blk);
     rec.e_leaf_clusters = cpu_to_le16(new_clusters);
     rec.e_flags = flags;
     status = ocfs2_et_insert_check(et, &rec);
     if (status) {
         mlog_errno(status);
         goto bail;
     }
 
     status = ocfs2_figure_insert_type(et, &last_eb_bh, &rec,
                       &free_records, &insert);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     trace_ocfs2_insert_extent(insert.ins_appending, insert.ins_contig,
                   insert.ins_contig_index, free_records,
                   insert.ins_tree_depth);
 
     if (insert.ins_contig == CONTIG_NONE && free_records == 0) {
         status = ocfs2_grow_tree(handle, et,
                      &insert.ins_tree_depth, &last_eb_bh,
                      meta_ac);
         if (status) {
             mlog_errno(status);
             goto bail;
         }
     }
 
     /* Finally, we can add clusters. This might rotate the tree for us. */
     status = ocfs2_do_insert_extent(handle, et, &rec, &insert);
     if (status < 0)
         mlog_errno(status);
     else
         ocfs2_et_extent_map_insert(et, &rec);
 
 bail:
     brelse(last_eb_bh);
 
     return status;
 }
 
 /*
  * Allcate and add clusters into the extent b-tree.
  * The new clusters(clusters_to_add) will be inserted at logical_offset.
  * The extent b-tree's root is specified by et, and
  * it is not limited to the file storage. Any extent tree can use this
  * function if it implements the proper ocfs2_extent_tree.
  */
 int ocfs2_add_clusters_in_btree(handle_t *handle,
                 struct ocfs2_extent_tree *et,
                 u32 *logical_offset,
                 u32 clusters_to_add,
                 int mark_unwritten,
                 struct ocfs2_alloc_context *data_ac,
                 struct ocfs2_alloc_context *meta_ac,
                 enum ocfs2_alloc_restarted *reason_ret)
 {
     int status = 0, err = 0;
     int need_free = 0;
     int free_extents;
     enum ocfs2_alloc_restarted reason = RESTART_NONE;
     u32 bit_off, num_bits;
     u64 block;
     u8 flags = 0;
     struct ocfs2_super *osb =
         OCFS2_SB(ocfs2_metadata_cache_get_super(et->et_ci));
 
     BUG_ON(!clusters_to_add);
 
     if (mark_unwritten)
         flags = OCFS2_EXT_UNWRITTEN;
 
     free_extents = ocfs2_num_free_extents(et);
     if (free_extents < 0) {
         status = free_extents;
         mlog_errno(status);
         goto leave;
     }
 
     /* there are two cases which could cause us to EAGAIN in the
      * we-need-more-metadata case:
      * 1) we haven't reserved *any*
      * 2) we are so fragmented, we've needed to add metadata too
      *    many times. */
     if (!free_extents && !meta_ac) {
         err = -1;
         status = -EAGAIN;
         reason = RESTART_META;
         goto leave;
     } else if ((!free_extents)
            && (ocfs2_alloc_context_bits_left(meta_ac)
                < ocfs2_extend_meta_needed(et->et_root_el))) {
         err = -2;
         status = -EAGAIN;
         reason = RESTART_META;
         goto leave;
     }
 
     status = __ocfs2_claim_clusters(handle, data_ac, 1,
                     clusters_to_add, &bit_off, &num_bits);
     if (status < 0) {
         if (status != -ENOSPC)
             mlog_errno(status);
         goto leave;
     }
 
     BUG_ON(num_bits > clusters_to_add);
 
     /* reserve our write early -- insert_extent may update the tree root */
     status = ocfs2_et_root_journal_access(handle, et,
                           OCFS2_JOURNAL_ACCESS_WRITE);
     if (status < 0) {
         mlog_errno(status);
         need_free = 1;
         goto bail;
     }
 
     block = ocfs2_clusters_to_blocks(osb->sb, bit_off);
     trace_ocfs2_add_clusters_in_btree(
          (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
          bit_off, num_bits);
     status = ocfs2_insert_extent(handle, et, *logical_offset, block,
                      num_bits, flags, meta_ac);
     if (status < 0) {
         mlog_errno(status);
         need_free = 1;
         goto bail;
     }
 
     ocfs2_journal_dirty(handle, et->et_root_bh);
 
     clusters_to_add -= num_bits;
     *logical_offset += num_bits;
 
     if (clusters_to_add) {
         err = clusters_to_add;
         status = -EAGAIN;
         reason = RESTART_TRANS;
     }
 
 bail:
     if (need_free) {
         if (data_ac->ac_which == OCFS2_AC_USE_LOCAL)
             ocfs2_free_local_alloc_bits(osb, handle, data_ac,
                     bit_off, num_bits);
         else
             ocfs2_free_clusters(handle,
                     data_ac->ac_inode,
                     data_ac->ac_bh,
                     ocfs2_clusters_to_blocks(osb->sb, bit_off),
                     num_bits);
     }
 
 leave:
     if (reason_ret)
         *reason_ret = reason;
     trace_ocfs2_add_clusters_in_btree_ret(status, reason, err);
     return status;
 }
 
 static void ocfs2_make_right_split_rec(struct super_block *sb,
                        struct ocfs2_extent_rec *split_rec,
                        u32 cpos,
                        struct ocfs2_extent_rec *rec)
 {
     u32 rec_cpos = le32_to_cpu(rec->e_cpos);
     u32 rec_range = rec_cpos + le16_to_cpu(rec->e_leaf_clusters);
 
     memset(split_rec, 0, sizeof(struct ocfs2_extent_rec));
 
     split_rec->e_cpos = cpu_to_le32(cpos);
     split_rec->e_leaf_clusters = cpu_to_le16(rec_range - cpos);
 
     split_rec->e_blkno = rec->e_blkno;
     le64_add_cpu(&split_rec->e_blkno,
              ocfs2_clusters_to_blocks(sb, cpos - rec_cpos));
 
     split_rec->e_flags = rec->e_flags;
 }
 
 static int ocfs2_split_and_insert(handle_t *handle,
                   struct ocfs2_extent_tree *et,
                   struct ocfs2_path *path,
                   struct buffer_head **last_eb_bh,
                   int split_index,
                   struct ocfs2_extent_rec *orig_split_rec,
                   struct ocfs2_alloc_context *meta_ac)
 {
     int ret = 0, depth;
     unsigned int insert_range, rec_range, do_leftright = 0;
     struct ocfs2_extent_rec tmprec;
     struct ocfs2_extent_list *rightmost_el;
     struct ocfs2_extent_rec rec;
     struct ocfs2_extent_rec split_rec = *orig_split_rec;
     struct ocfs2_insert_type insert;
     struct ocfs2_extent_block *eb;
 
 leftright:
     /*
      * Store a copy of the record on the stack - it might move
      * around as the tree is manipulated below.
      */
     rec = path_leaf_el(path)->l_recs[split_index];
 
     rightmost_el = et->et_root_el;
 
     depth = le16_to_cpu(rightmost_el->l_tree_depth);
     if (depth) {
         BUG_ON(!(*last_eb_bh));
         eb = (struct ocfs2_extent_block *) (*last_eb_bh)->b_data;
         rightmost_el = &eb->h_list;
     }
 
     if (le16_to_cpu(rightmost_el->l_next_free_rec) ==
         le16_to_cpu(rightmost_el->l_count)) {
         ret = ocfs2_grow_tree(handle, et,
                       &depth, last_eb_bh, meta_ac);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     memset(&insert, 0, sizeof(struct ocfs2_insert_type));
     insert.ins_appending = APPEND_NONE;
     insert.ins_contig = CONTIG_NONE;
     insert.ins_tree_depth = depth;
 
     insert_range = le32_to_cpu(split_rec.e_cpos) +
         le16_to_cpu(split_rec.e_leaf_clusters);
     rec_range = le32_to_cpu(rec.e_cpos) +
         le16_to_cpu(rec.e_leaf_clusters);
 
     if (split_rec.e_cpos == rec.e_cpos) {
         insert.ins_split = SPLIT_LEFT;
     } else if (insert_range == rec_range) {
         insert.ins_split = SPLIT_RIGHT;
     } else {
         /*
          * Left/right split. We fake this as a right split
          * first and then make a second pass as a left split.
          */
         insert.ins_split = SPLIT_RIGHT;
 
         ocfs2_make_right_split_rec(ocfs2_metadata_cache_get_super(et->et_ci),
                        &tmprec, insert_range, &rec);
 
         split_rec = tmprec;
 
         BUG_ON(do_leftright);
         do_leftright = 1;
     }
 
     ret = ocfs2_do_insert_extent(handle, et, &split_rec, &insert);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     if (do_leftright == 1) {
         u32 cpos;
         struct ocfs2_extent_list *el;
 
         do_leftright++;
         split_rec = *orig_split_rec;
 
         ocfs2_reinit_path(path, 1);
 
         cpos = le32_to_cpu(split_rec.e_cpos);
         ret = ocfs2_find_path(et->et_ci, path, cpos);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         el = path_leaf_el(path);
         split_index = ocfs2_search_extent_list(el, cpos);
         if (split_index == -1) {
             ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
                     "Owner %llu has an extent at cpos %u which can no longer be found\n",
                     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
                     cpos);
             ret = -EROFS;
             goto out;
         }
         goto leftright;
     }
 out:
 
     return ret;
 }
 
 static int ocfs2_replace_extent_rec(handle_t *handle,
                     struct ocfs2_extent_tree *et,
                     struct ocfs2_path *path,
                     struct ocfs2_extent_list *el,
                     int split_index,
                     struct ocfs2_extent_rec *split_rec)
 {
     int ret;
 
     ret = ocfs2_path_bh_journal_access(handle, et->et_ci, path,
                        path_num_items(path) - 1);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     el->l_recs[split_index] = *split_rec;
 
     ocfs2_journal_dirty(handle, path_leaf_bh(path));
 out:
     return ret;
 }
 
 /*
  * Split part or all of the extent record at split_index in the leaf
  * pointed to by path. Merge with the contiguous extent record if needed.
  *
  * Care is taken to handle contiguousness so as to not grow the tree.
  *
  * meta_ac is not strictly necessary - we only truly need it if growth
  * of the tree is required. All other cases will degrade into a less
  * optimal tree layout.
  *
  * last_eb_bh should be the rightmost leaf block for any extent
  * btree. Since a split may grow the tree or a merge might shrink it,
  * the caller cannot trust the contents of that buffer after this call.
  *
  * This code is optimized for readability - several passes might be
  * made over certain portions of the tree. All of those blocks will
  * have been brought into cache (and pinned via the journal), so the
  * extra overhead is not expressed in terms of disk reads.
  */
 int ocfs2_split_extent(handle_t *handle,
                struct ocfs2_extent_tree *et,
                struct ocfs2_path *path,
                int split_index,
                struct ocfs2_extent_rec *split_rec,
                struct ocfs2_alloc_context *meta_ac,
                struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
     int ret = 0;
     struct ocfs2_extent_list *el = path_leaf_el(path);
     struct buffer_head *last_eb_bh = NULL;
     struct ocfs2_extent_rec *rec = &el->l_recs[split_index];
     struct ocfs2_merge_ctxt ctxt;
 
     if (le32_to_cpu(rec->e_cpos) > le32_to_cpu(split_rec->e_cpos) ||
         ((le32_to_cpu(rec->e_cpos) + le16_to_cpu(rec->e_leaf_clusters)) <
          (le32_to_cpu(split_rec->e_cpos) + le16_to_cpu(split_rec->e_leaf_clusters)))) {
         ret = -EIO;
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_figure_merge_contig_type(et, path, el,
                          split_index,
                          split_rec,
                          &ctxt);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     /*
      * The core merge / split code wants to know how much room is
      * left in this allocation tree, so we pass the
      * rightmost extent list.
      */
     if (path->p_tree_depth) {
         ret = ocfs2_read_extent_block(et->et_ci,
                           ocfs2_et_get_last_eb_blk(et),
                           &last_eb_bh);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     if (rec->e_cpos == split_rec->e_cpos &&
         rec->e_leaf_clusters == split_rec->e_leaf_clusters)
         ctxt.c_split_covers_rec = 1;
     else
         ctxt.c_split_covers_rec = 0;
 
     ctxt.c_has_empty_extent = ocfs2_is_empty_extent(&el->l_recs[0]);
 
     trace_ocfs2_split_extent(split_index, ctxt.c_contig_type,
                  ctxt.c_has_empty_extent,
                  ctxt.c_split_covers_rec);
 
     if (ctxt.c_contig_type == CONTIG_NONE) {
         if (ctxt.c_split_covers_rec)
             ret = ocfs2_replace_extent_rec(handle, et, path, el,
                                split_index, split_rec);
         else
             ret = ocfs2_split_and_insert(handle, et, path,
                              &last_eb_bh, split_index,
                              split_rec, meta_ac);
         if (ret)
             mlog_errno(ret);
     } else {
         ret = ocfs2_try_to_merge_extent(handle, et, path,
                         split_index, split_rec,
                         dealloc, &ctxt);
         if (ret)
             mlog_errno(ret);
     }
 
 out:
     brelse(last_eb_bh);
     return ret;
 }
 
 /*
  * Change the flags of the already-existing extent at cpos for len clusters.
  *
  * new_flags: the flags we want to set.
  * clear_flags: the flags we want to clear.
  * phys: the new physical offset we want this new extent starts from.
  *
  * If the existing extent is larger than the request, initiate a
  * split. An attempt will be made at merging with adjacent extents.
  *
  * The caller is responsible for passing down meta_ac if we'll need it.
  */
 int ocfs2_change_extent_flag(handle_t *handle,
                  struct ocfs2_extent_tree *et,
                  u32 cpos, u32 len, u32 phys,
                  struct ocfs2_alloc_context *meta_ac,
                  struct ocfs2_cached_dealloc_ctxt *dealloc,
                  int new_flags, int clear_flags)
 {
     int ret, index;
     struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
     u64 start_blkno = ocfs2_clusters_to_blocks(sb, phys);
     struct ocfs2_extent_rec split_rec;
     struct ocfs2_path *left_path = NULL;
     struct ocfs2_extent_list *el;
     struct ocfs2_extent_rec *rec;
 
     left_path = ocfs2_new_path_from_et(et);
     if (!left_path) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_find_path(et->et_ci, left_path, cpos);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
     el = path_leaf_el(left_path);
 
     index = ocfs2_search_extent_list(el, cpos);
     if (index == -1) {
         ocfs2_error(sb,
                 "Owner %llu has an extent at cpos %u which can no longer be found\n",
                 (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
                 cpos);
         ret = -EROFS;
         goto out;
     }
 
     ret = -EIO;
     rec = &el->l_recs[index];
     if (new_flags && (rec->e_flags & new_flags)) {
         mlog(ML_ERROR, "Owner %llu tried to set %d flags on an "
              "extent that already had them\n",
              (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
              new_flags);
         goto out;
     }
 
     if (clear_flags && !(rec->e_flags & clear_flags)) {
         mlog(ML_ERROR, "Owner %llu tried to clear %d flags on an "
              "extent that didn't have them\n",
              (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
              clear_flags);
         goto out;
     }
 
     memset(&split_rec, 0, sizeof(struct ocfs2_extent_rec));
     split_rec.e_cpos = cpu_to_le32(cpos);
     split_rec.e_leaf_clusters = cpu_to_le16(len);
     split_rec.e_blkno = cpu_to_le64(start_blkno);
     split_rec.e_flags = rec->e_flags;
     if (new_flags)
         split_rec.e_flags |= new_flags;
     if (clear_flags)
         split_rec.e_flags &= ~clear_flags;
 
     ret = ocfs2_split_extent(handle, et, left_path,
                  index, &split_rec, meta_ac,
                  dealloc);
     if (ret)
         mlog_errno(ret);
 
 out:
     ocfs2_free_path(left_path);
     return ret;
 
 }
 
 /*
  * Mark the already-existing extent at cpos as written for len clusters.
  * This removes the unwritten extent flag.
  *
  * If the existing extent is larger than the request, initiate a
  * split. An attempt will be made at merging with adjacent extents.
  *
  * The caller is responsible for passing down meta_ac if we'll need it.
  */
 int ocfs2_mark_extent_written(struct inode *inode,
                   struct ocfs2_extent_tree *et,
                   handle_t *handle, u32 cpos, u32 len, u32 phys,
                   struct ocfs2_alloc_context *meta_ac,
                   struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
     int ret;
 
     trace_ocfs2_mark_extent_written(
         (unsigned long long)OCFS2_I(inode)->ip_blkno,
         cpos, len, phys);
 
     if (!ocfs2_writes_unwritten_extents(OCFS2_SB(inode->i_sb))) {
         ocfs2_error(inode->i_sb, "Inode %llu has unwritten extents that are being written to, but the feature bit is not set in the super block\n",
                 (unsigned long long)OCFS2_I(inode)->ip_blkno);
         ret = -EROFS;
         goto out;
     }
 
     /*
      * XXX: This should be fixed up so that we just re-insert the
      * next extent records.
      */
     ocfs2_et_extent_map_truncate(et, 0);
 
     ret = ocfs2_change_extent_flag(handle, et, cpos,
                        len, phys, meta_ac, dealloc,
                        0, OCFS2_EXT_UNWRITTEN);
     if (ret)
         mlog_errno(ret);
 
 out:
     return ret;
 }
 
 static int ocfs2_split_tree(handle_t *handle, struct ocfs2_extent_tree *et,
                 struct ocfs2_path *path,
                 int index, u32 new_range,
                 struct ocfs2_alloc_context *meta_ac)
 {
     int ret, depth, credits;
     struct buffer_head *last_eb_bh = NULL;
     struct ocfs2_extent_block *eb;
     struct ocfs2_extent_list *rightmost_el, *el;
     struct ocfs2_extent_rec split_rec;
     struct ocfs2_extent_rec *rec;
     struct ocfs2_insert_type insert;
 
     /*
      * Setup the record to split before we grow the tree.
      */
     el = path_leaf_el(path);
     rec = &el->l_recs[index];
     ocfs2_make_right_split_rec(ocfs2_metadata_cache_get_super(et->et_ci),
                    &split_rec, new_range, rec);
 
     depth = path->p_tree_depth;
     if (depth > 0) {
         ret = ocfs2_read_extent_block(et->et_ci,
                           ocfs2_et_get_last_eb_blk(et),
                           &last_eb_bh);
         if (ret < 0) {
             mlog_errno(ret);
             goto out;
         }
 
         eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
         rightmost_el = &eb->h_list;
     } else
         rightmost_el = path_leaf_el(path);
 
     credits = path->p_tree_depth +
           ocfs2_extend_meta_needed(et->et_root_el);
     ret = ocfs2_extend_trans(handle, credits);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     if (le16_to_cpu(rightmost_el->l_next_free_rec) ==
         le16_to_cpu(rightmost_el->l_count)) {
         ret = ocfs2_grow_tree(handle, et, &depth, &last_eb_bh,
                       meta_ac);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     memset(&insert, 0, sizeof(struct ocfs2_insert_type));
     insert.ins_appending = APPEND_NONE;
     insert.ins_contig = CONTIG_NONE;
     insert.ins_split = SPLIT_RIGHT;
     insert.ins_tree_depth = depth;
 
     ret = ocfs2_do_insert_extent(handle, et, &split_rec, &insert);
     if (ret)
         mlog_errno(ret);
 
 out:
     brelse(last_eb_bh);
     return ret;
 }
 
 static int ocfs2_truncate_rec(handle_t *handle,
                   struct ocfs2_extent_tree *et,
                   struct ocfs2_path *path, int index,
                   struct ocfs2_cached_dealloc_ctxt *dealloc,
                   u32 cpos, u32 len)
 {
     int ret;
     u32 left_cpos, rec_range, trunc_range;
     int is_rightmost_tree_rec = 0;
     struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
     struct ocfs2_path *left_path = NULL;
     struct ocfs2_extent_list *el = path_leaf_el(path);
     struct ocfs2_extent_rec *rec;
     struct ocfs2_extent_block *eb;
 
     if (ocfs2_is_empty_extent(&el->l_recs[0]) && index > 0) {
         /* extend credit for ocfs2_remove_rightmost_path */
         ret = ocfs2_extend_rotate_transaction(handle, 0,
                 jbd2_handle_buffer_credits(handle),
                 path);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         ret = ocfs2_rotate_tree_left(handle, et, path, dealloc);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         index--;
     }
 
     if (index == (le16_to_cpu(el->l_next_free_rec) - 1) &&
         path->p_tree_depth) {
         /*
          * Check whether this is the rightmost tree record. If
          * we remove all of this record or part of its right
          * edge then an update of the record lengths above it
          * will be required.
          */
         eb = (struct ocfs2_extent_block *)path_leaf_bh(path)->b_data;
         if (eb->h_next_leaf_blk == 0)
             is_rightmost_tree_rec = 1;
     }
 
     rec = &el->l_recs[index];
     if (index == 0 && path->p_tree_depth &&
         le32_to_cpu(rec->e_cpos) == cpos) {
         /*
          * Changing the leftmost offset (via partial or whole
          * record truncate) of an interior (or rightmost) path
          * means we have to update the subtree that is formed
          * by this leaf and the one to it's left.
          *
          * There are two cases we can skip:
          *   1) Path is the leftmost one in our btree.
          *   2) The leaf is rightmost and will be empty after
          *      we remove the extent record - the rotate code
          *      knows how to update the newly formed edge.
          */
 
         ret = ocfs2_find_cpos_for_left_leaf(sb, path, &left_cpos);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         if (left_cpos && le16_to_cpu(el->l_next_free_rec) > 1) {
             left_path = ocfs2_new_path_from_path(path);
             if (!left_path) {
                 ret = -ENOMEM;
                 mlog_errno(ret);
                 goto out;
             }
 
             ret = ocfs2_find_path(et->et_ci, left_path,
                           left_cpos);
             if (ret) {
                 mlog_errno(ret);
                 goto out;
             }
         }
     }
 
     ret = ocfs2_extend_rotate_transaction(handle, 0,
                     jbd2_handle_buffer_credits(handle),
                     path);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_journal_access_path(et->et_ci, handle, path);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_journal_access_path(et->et_ci, handle, left_path);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     rec_range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
     trunc_range = cpos + len;
 
     if (le32_to_cpu(rec->e_cpos) == cpos && rec_range == trunc_range) {
         int next_free;
 
         memset(rec, 0, sizeof(*rec));
         ocfs2_cleanup_merge(el, index);
 
         next_free = le16_to_cpu(el->l_next_free_rec);
         if (is_rightmost_tree_rec && next_free > 1) {
             /*
              * We skip the edge update if this path will
              * be deleted by the rotate code.
              */
             rec = &el->l_recs[next_free - 1];
             ocfs2_adjust_rightmost_records(handle, et, path,
                                rec);
         }
     } else if (le32_to_cpu(rec->e_cpos) == cpos) {
         /* Remove leftmost portion of the record. */
         le32_add_cpu(&rec->e_cpos, len);
         le64_add_cpu(&rec->e_blkno, ocfs2_clusters_to_blocks(sb, len));
         le16_add_cpu(&rec->e_leaf_clusters, -len);
     } else if (rec_range == trunc_range) {
         /* Remove rightmost portion of the record */
         le16_add_cpu(&rec->e_leaf_clusters, -len);
         if (is_rightmost_tree_rec)
             ocfs2_adjust_rightmost_records(handle, et, path, rec);
     } else {
         /* Caller should have trapped this. */
         mlog(ML_ERROR, "Owner %llu: Invalid record truncate: (%u, %u) "
              "(%u, %u)\n",
              (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
              le32_to_cpu(rec->e_cpos),
              le16_to_cpu(rec->e_leaf_clusters), cpos, len);
         BUG();
     }
 
     if (left_path) {
         int subtree_index;
 
         subtree_index = ocfs2_find_subtree_root(et, left_path, path);
         ocfs2_complete_edge_insert(handle, left_path, path,
                        subtree_index);
     }
 
     ocfs2_journal_dirty(handle, path_leaf_bh(path));
 
     ret = ocfs2_rotate_tree_left(handle, et, path, dealloc);
     if (ret)
         mlog_errno(ret);
 
 out:
     ocfs2_free_path(left_path);
     return ret;
 }
 
 int ocfs2_remove_extent(handle_t *handle,
             struct ocfs2_extent_tree *et,
             u32 cpos, u32 len,
             struct ocfs2_alloc_context *meta_ac,
             struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
     int ret, index;
     u32 rec_range, trunc_range;
     struct ocfs2_extent_rec *rec;
     struct ocfs2_extent_list *el;
     struct ocfs2_path *path = NULL;
 
     /*
      * XXX: Why are we truncating to 0 instead of wherever this
      * affects us?
      */
     ocfs2_et_extent_map_truncate(et, 0);
 
     path = ocfs2_new_path_from_et(et);
     if (!path) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_find_path(et->et_ci, path, cpos);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     el = path_leaf_el(path);
     index = ocfs2_search_extent_list(el, cpos);
     if (index == -1) {
         ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
                 "Owner %llu has an extent at cpos %u which can no longer be found\n",
                 (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
                 cpos);
         ret = -EROFS;
         goto out;
     }
 
     /*
      * We have 3 cases of extent removal:
      *   1) Range covers the entire extent rec
      *   2) Range begins or ends on one edge of the extent rec
      *   3) Range is in the middle of the extent rec (no shared edges)
      *
      * For case 1 we remove the extent rec and left rotate to
      * fill the hole.
      *
      * For case 2 we just shrink the existing extent rec, with a
      * tree update if the shrinking edge is also the edge of an
      * extent block.
      *
      * For case 3 we do a right split to turn the extent rec into
      * something case 2 can handle.
      */
     rec = &el->l_recs[index];
     rec_range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
     trunc_range = cpos + len;
 
     BUG_ON(cpos < le32_to_cpu(rec->e_cpos) || trunc_range > rec_range);
 
     trace_ocfs2_remove_extent(
         (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
         cpos, len, index, le32_to_cpu(rec->e_cpos),
         ocfs2_rec_clusters(el, rec));
 
     if (le32_to_cpu(rec->e_cpos) == cpos || rec_range == trunc_range) {
         ret = ocfs2_truncate_rec(handle, et, path, index, dealloc,
                      cpos, len);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     } else {
         ret = ocfs2_split_tree(handle, et, path, index,
                        trunc_range, meta_ac);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         /*
          * The split could have manipulated the tree enough to
          * move the record location, so we have to look for it again.
          */
         ocfs2_reinit_path(path, 1);
 
         ret = ocfs2_find_path(et->et_ci, path, cpos);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         el = path_leaf_el(path);
         index = ocfs2_search_extent_list(el, cpos);
         if (index == -1) {
             ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
                     "Owner %llu: split at cpos %u lost record\n",
                     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
                     cpos);
             ret = -EROFS;
             goto out;
         }
 
         /*
          * Double check our values here. If anything is fishy,
          * it's easier to catch it at the top level.
          */
         rec = &el->l_recs[index];
         rec_range = le32_to_cpu(rec->e_cpos) +
             ocfs2_rec_clusters(el, rec);
         if (rec_range != trunc_range) {
             ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
                     "Owner %llu: error after split at cpos %u trunc len %u, existing record is (%u,%u)\n",
                     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
                     cpos, len, le32_to_cpu(rec->e_cpos),
                     ocfs2_rec_clusters(el, rec));
             ret = -EROFS;
             goto out;
         }
 
         ret = ocfs2_truncate_rec(handle, et, path, index, dealloc,
                      cpos, len);
         if (ret)
             mlog_errno(ret);
     }
 
 out:
     ocfs2_free_path(path);
     return ret;
 }
 
 /*
  * ocfs2_reserve_blocks_for_rec_trunc() would look basically the
  * same as ocfs2_lock_alloctors(), except for it accepts a blocks
  * number to reserve some extra blocks, and it only handles meta
  * data allocations.
  *
  * Currently, only ocfs2_remove_btree_range() uses it for truncating
  * and punching holes.
  */
 static int ocfs2_reserve_blocks_for_rec_trunc(struct inode *inode,
                           struct ocfs2_extent_tree *et,
                           u32 extents_to_split,
                           struct ocfs2_alloc_context **ac,
                           int extra_blocks)
 {
     int ret = 0, num_free_extents;
     unsigned int max_recs_needed = 2 * extents_to_split;
     struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 
     *ac = NULL;
 
     num_free_extents = ocfs2_num_free_extents(et);
     if (num_free_extents < 0) {
         ret = num_free_extents;
         mlog_errno(ret);
         goto out;
     }
 
     if (!num_free_extents ||
         (ocfs2_sparse_alloc(osb) && num_free_extents < max_recs_needed))
         extra_blocks += ocfs2_extend_meta_needed(et->et_root_el);
 
     if (extra_blocks) {
         ret = ocfs2_reserve_new_metadata_blocks(osb, extra_blocks, ac);
         if (ret < 0) {
             if (ret != -ENOSPC)
                 mlog_errno(ret);
         }
     }
 
 out:
     if (ret) {
         if (*ac) {
             ocfs2_free_alloc_context(*ac);
             *ac = NULL;
         }
     }
 
     return ret;
 }
 
 int ocfs2_remove_btree_range(struct inode *inode,
                  struct ocfs2_extent_tree *et,
                  u32 cpos, u32 phys_cpos, u32 len, int flags,
                  struct ocfs2_cached_dealloc_ctxt *dealloc,
                  u64 refcount_loc, bool refcount_tree_locked)
 {
     int ret, credits = 0, extra_blocks = 0;
     u64 phys_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys_cpos);
     struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
     struct inode *tl_inode = osb->osb_tl_inode;
     handle_t *handle;
     struct ocfs2_alloc_context *meta_ac = NULL;
     struct ocfs2_refcount_tree *ref_tree = NULL;
 
     if ((flags & OCFS2_EXT_REFCOUNTED) && len) {
         BUG_ON(!ocfs2_is_refcount_inode(inode));
 
         if (!refcount_tree_locked) {
             ret = ocfs2_lock_refcount_tree(osb, refcount_loc, 1,
                                &ref_tree, NULL);
             if (ret) {
                 mlog_errno(ret);
                 goto bail;
             }
         }
 
         ret = ocfs2_prepare_refcount_change_for_del(inode,
                                 refcount_loc,
                                 phys_blkno,
                                 len,
                                 &credits,
                                 &extra_blocks);
         if (ret < 0) {
             mlog_errno(ret);
             goto bail;
         }
     }
 
     ret = ocfs2_reserve_blocks_for_rec_trunc(inode, et, 1, &meta_ac,
                          extra_blocks);
     if (ret) {
         mlog_errno(ret);
         goto bail;
     }
 
     inode_lock(tl_inode);
 
     if (ocfs2_truncate_log_needs_flush(osb)) {
         ret = __ocfs2_flush_truncate_log(osb);
         if (ret < 0) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     handle = ocfs2_start_trans(osb,
             ocfs2_remove_extent_credits(osb->sb) + credits);
     if (IS_ERR(handle)) {
         ret = PTR_ERR(handle);
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_et_root_journal_access(handle, et,
                        OCFS2_JOURNAL_ACCESS_WRITE);
     if (ret) {
         mlog_errno(ret);
         goto out_commit;
     }
 
     dquot_free_space_nodirty(inode,
                   ocfs2_clusters_to_bytes(inode->i_sb, len));
 
     ret = ocfs2_remove_extent(handle, et, cpos, len, meta_ac, dealloc);
     if (ret) {
         mlog_errno(ret);
         goto out_commit;
     }
 
     ocfs2_et_update_clusters(et, -len);
     ocfs2_update_inode_fsync_trans(handle, inode, 1);
 
     ocfs2_journal_dirty(handle, et->et_root_bh);
 
     if (phys_blkno) {
         if (flags & OCFS2_EXT_REFCOUNTED)
             ret = ocfs2_decrease_refcount(inode, handle,
                     ocfs2_blocks_to_clusters(osb->sb,
                                  phys_blkno),
                     len, meta_ac,
                     dealloc, 1);
         else
             ret = ocfs2_truncate_log_append(osb, handle,
                             phys_blkno, len);
         if (ret)
             mlog_errno(ret);
 
     }
 
 out_commit:
     ocfs2_commit_trans(osb, handle);
 out:
     inode_unlock(tl_inode);
 bail:
     if (meta_ac)
         ocfs2_free_alloc_context(meta_ac);
 
     if (ref_tree)
         ocfs2_unlock_refcount_tree(osb, ref_tree, 1);
 
     return ret;
 }
 
 int ocfs2_truncate_log_needs_flush(struct ocfs2_super *osb)
 {
     struct buffer_head *tl_bh = osb->osb_tl_bh;
     struct ocfs2_dinode *di;
     struct ocfs2_truncate_log *tl;
 
     di = (struct ocfs2_dinode *) tl_bh->b_data;
     tl = &di->id2.i_dealloc;
 
     mlog_bug_on_msg(le16_to_cpu(tl->tl_used) > le16_to_cpu(tl->tl_count),
             "slot %d, invalid truncate log parameters: used = "
             "%u, count = %u\n", osb->slot_num,
             le16_to_cpu(tl->tl_used), le16_to_cpu(tl->tl_count));
     return le16_to_cpu(tl->tl_used) == le16_to_cpu(tl->tl_count);
 }
 
 static int ocfs2_truncate_log_can_coalesce(struct ocfs2_truncate_log *tl,
                        unsigned int new_start)
 {
     unsigned int tail_index;
     unsigned int current_tail;
 
     /* No records, nothing to coalesce */
     if (!le16_to_cpu(tl->tl_used))
         return 0;
 
     tail_index = le16_to_cpu(tl->tl_used) - 1;
     current_tail = le32_to_cpu(tl->tl_recs[tail_index].t_start);
     current_tail += le32_to_cpu(tl->tl_recs[tail_index].t_clusters);
 
     return current_tail == new_start;
 }
 
 int ocfs2_truncate_log_append(struct ocfs2_super *osb,
                   handle_t *handle,
                   u64 start_blk,
                   unsigned int num_clusters)
 {
     int status, index;
     unsigned int start_cluster, tl_count;
     struct inode *tl_inode = osb->osb_tl_inode;
     struct buffer_head *tl_bh = osb->osb_tl_bh;
     struct ocfs2_dinode *di;
     struct ocfs2_truncate_log *tl;
 
     BUG_ON(inode_trylock(tl_inode));
 
     start_cluster = ocfs2_blocks_to_clusters(osb->sb, start_blk);
 
     di = (struct ocfs2_dinode *) tl_bh->b_data;
 
     /* tl_bh is loaded from ocfs2_truncate_log_init().  It's validated
      * by the underlying call to ocfs2_read_inode_block(), so any
      * corruption is a code bug */
     BUG_ON(!OCFS2_IS_VALID_DINODE(di));
 
     tl = &di->id2.i_dealloc;
     tl_count = le16_to_cpu(tl->tl_count);
     mlog_bug_on_msg(tl_count > ocfs2_truncate_recs_per_inode(osb->sb) ||
             tl_count == 0,
             "Truncate record count on #%llu invalid "
             "wanted %u, actual %u\n",
             (unsigned long long)OCFS2_I(tl_inode)->ip_blkno,
             ocfs2_truncate_recs_per_inode(osb->sb),
             le16_to_cpu(tl->tl_count));
 
     /* Caller should have known to flush before calling us. */
     index = le16_to_cpu(tl->tl_used);
     if (index >= tl_count) {
         status = -ENOSPC;
         mlog_errno(status);
         goto bail;
     }
 
     status = ocfs2_journal_access_di(handle, INODE_CACHE(tl_inode), tl_bh,
                      OCFS2_JOURNAL_ACCESS_WRITE);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     trace_ocfs2_truncate_log_append(
         (unsigned long long)OCFS2_I(tl_inode)->ip_blkno, index,
         start_cluster, num_clusters);
     if (ocfs2_truncate_log_can_coalesce(tl, start_cluster)) {
         /*
          * Move index back to the record we are coalescing with.
          * ocfs2_truncate_log_can_coalesce() guarantees nonzero
          */
         index--;
 
         num_clusters += le32_to_cpu(tl->tl_recs[index].t_clusters);
         trace_ocfs2_truncate_log_append(
             (unsigned long long)OCFS2_I(tl_inode)->ip_blkno,
             index, le32_to_cpu(tl->tl_recs[index].t_start),
             num_clusters);
     } else {
         tl->tl_recs[index].t_start = cpu_to_le32(start_cluster);
         tl->tl_used = cpu_to_le16(index + 1);
     }
     tl->tl_recs[index].t_clusters = cpu_to_le32(num_clusters);
 
     ocfs2_journal_dirty(handle, tl_bh);
 
     osb->truncated_clusters += num_clusters;
 bail:
     return status;
 }
 
 static int ocfs2_replay_truncate_records(struct ocfs2_super *osb,
                      struct inode *data_alloc_inode,
                      struct buffer_head *data_alloc_bh)
 {
     int status = 0;
     int i;
     unsigned int num_clusters;
     u64 start_blk;
     struct ocfs2_truncate_rec rec;
     struct ocfs2_dinode *di;
     struct ocfs2_truncate_log *tl;
     struct inode *tl_inode = osb->osb_tl_inode;
     struct buffer_head *tl_bh = osb->osb_tl_bh;
     handle_t *handle;
 
     di = (struct ocfs2_dinode *) tl_bh->b_data;
     tl = &di->id2.i_dealloc;
     i = le16_to_cpu(tl->tl_used) - 1;
     while (i >= 0) {
         handle = ocfs2_start_trans(osb, OCFS2_TRUNCATE_LOG_FLUSH_ONE_REC);
         if (IS_ERR(handle)) {
             status = PTR_ERR(handle);
             mlog_errno(status);
             goto bail;
         }
 
         /* Caller has given us at least enough credits to
          * update the truncate log dinode */
         status = ocfs2_journal_access_di(handle, INODE_CACHE(tl_inode), tl_bh,
                          OCFS2_JOURNAL_ACCESS_WRITE);
         if (status < 0) {
             ocfs2_commit_trans(osb, handle);
             mlog_errno(status);
             goto bail;
         }
 
         tl->tl_used = cpu_to_le16(i);
 
         ocfs2_journal_dirty(handle, tl_bh);
 
         rec = tl->tl_recs[i];
         start_blk = ocfs2_clusters_to_blocks(data_alloc_inode->i_sb,
                             le32_to_cpu(rec.t_start));
         num_clusters = le32_to_cpu(rec.t_clusters);
 
         /* if start_blk is not set, we ignore the record as
          * invalid. */
         if (start_blk) {
             trace_ocfs2_replay_truncate_records(
                 (unsigned long long)OCFS2_I(tl_inode)->ip_blkno,
                 i, le32_to_cpu(rec.t_start), num_clusters);
 
             status = ocfs2_free_clusters(handle, data_alloc_inode,
                              data_alloc_bh, start_blk,
                              num_clusters);
             if (status < 0) {
                 ocfs2_commit_trans(osb, handle);
                 mlog_errno(status);
                 goto bail;
             }
         }
 
         ocfs2_commit_trans(osb, handle);
         i--;
     }
 
     osb->truncated_clusters = 0;
 
 bail:
     return status;
 }
 
 /* Expects you to already be holding tl_inode->i_rwsem */
 int __ocfs2_flush_truncate_log(struct ocfs2_super *osb)
 {
     int status;
     unsigned int num_to_flush;
     struct inode *tl_inode = osb->osb_tl_inode;
     struct inode *data_alloc_inode = NULL;
     struct buffer_head *tl_bh = osb->osb_tl_bh;
     struct buffer_head *data_alloc_bh = NULL;
     struct ocfs2_dinode *di;
     struct ocfs2_truncate_log *tl;
     struct ocfs2_journal *journal = osb->journal;
 
     BUG_ON(inode_trylock(tl_inode));
 
     di = (struct ocfs2_dinode *) tl_bh->b_data;
 
     /* tl_bh is loaded from ocfs2_truncate_log_init().  It's validated
      * by the underlying call to ocfs2_read_inode_block(), so any
      * corruption is a code bug */
     BUG_ON(!OCFS2_IS_VALID_DINODE(di));
 
     tl = &di->id2.i_dealloc;
     num_to_flush = le16_to_cpu(tl->tl_used);
     trace_ocfs2_flush_truncate_log(
         (unsigned long long)OCFS2_I(tl_inode)->ip_blkno,
         num_to_flush);
     if (!num_to_flush) {
         status = 0;
         goto out;
     }
 
     /* Appending truncate log(TA) and flushing truncate log(TF) are
      * two separated transactions. They can be both committed but not
      * checkpointed. If crash occurs then, both two transaction will be
      * replayed with several already released to global bitmap clusters.
      * Then truncate log will be replayed resulting in cluster double free.
      */
     jbd2_journal_lock_updates(journal->j_journal);
     status = jbd2_journal_flush(journal->j_journal, 0);
     jbd2_journal_unlock_updates(journal->j_journal);
     if (status < 0) {
         mlog_errno(status);
         goto out;
     }
 
     data_alloc_inode = ocfs2_get_system_file_inode(osb,
                                GLOBAL_BITMAP_SYSTEM_INODE,
                                OCFS2_INVALID_SLOT);
     if (!data_alloc_inode) {
         status = -EINVAL;
         mlog(ML_ERROR, "Could not get bitmap inode!\n");
         goto out;
     }
 
     inode_lock(data_alloc_inode);
 
     status = ocfs2_inode_lock(data_alloc_inode, &data_alloc_bh, 1);
     if (status < 0) {
         mlog_errno(status);
         goto out_mutex;
     }
 
     status = ocfs2_replay_truncate_records(osb, data_alloc_inode,
                            data_alloc_bh);
     if (status < 0)
         mlog_errno(status);
 
     brelse(data_alloc_bh);
     ocfs2_inode_unlock(data_alloc_inode, 1);
 
 out_mutex:
     inode_unlock(data_alloc_inode);
     iput(data_alloc_inode);
 
 out:
     return status;
 }
 
 int ocfs2_flush_truncate_log(struct ocfs2_super *osb)
 {
     int status;
     struct inode *tl_inode = osb->osb_tl_inode;
 
     inode_lock(tl_inode);
     status = __ocfs2_flush_truncate_log(osb);
     inode_unlock(tl_inode);
 
     return status;
 }
 
 static void ocfs2_truncate_log_worker(struct work_struct *work)
 {
     int status;
     struct ocfs2_super *osb =
         container_of(work, struct ocfs2_super,
                  osb_truncate_log_wq.work);
 
     status = ocfs2_flush_truncate_log(osb);
     if (status < 0)
         mlog_errno(status);
     else
         ocfs2_init_steal_slots(osb);
 }
 
 #define OCFS2_TRUNCATE_LOG_FLUSH_INTERVAL (2 * HZ)
 void ocfs2_schedule_truncate_log_flush(struct ocfs2_super *osb,
                        int cancel)
 {
     if (osb->osb_tl_inode &&
             atomic_read(&osb->osb_tl_disable) == 0) {
         /* We want to push off log flushes while truncates are
          * still running. */
         if (cancel)
             cancel_delayed_work(&osb->osb_truncate_log_wq);
 
         queue_delayed_work(osb->ocfs2_wq, &osb->osb_truncate_log_wq,
                    OCFS2_TRUNCATE_LOG_FLUSH_INTERVAL);
     }
 }
 
 /*
  * Try to flush truncate logs if we can free enough clusters from it.
  * As for return value, "< 0" means error, "0" no space and "1" means
  * we have freed enough spaces and let the caller try to allocate again.
  */
 int ocfs2_try_to_free_truncate_log(struct ocfs2_super *osb,
                     unsigned int needed)
 {
     tid_t target;
     int ret = 0;
     unsigned int truncated_clusters;
 
     inode_lock(osb->osb_tl_inode);
     truncated_clusters = osb->truncated_clusters;
     inode_unlock(osb->osb_tl_inode);
 
     /*
      * Check whether we can succeed in allocating if we free
      * the truncate log.
      */
     if (truncated_clusters < needed)
         goto out;
 
     ret = ocfs2_flush_truncate_log(osb);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     if (jbd2_journal_start_commit(osb->journal->j_journal, &target)) {
         jbd2_log_wait_commit(osb->journal->j_journal, target);
         ret = 1;
     }
 out:
     return ret;
 }
 
 static int ocfs2_get_truncate_log_info(struct ocfs2_super *osb,
                        int slot_num,
                        struct inode **tl_inode,
                        struct buffer_head **tl_bh)
 {
     int status;
     struct inode *inode = NULL;
     struct buffer_head *bh = NULL;
 
     inode = ocfs2_get_system_file_inode(osb,
                        TRUNCATE_LOG_SYSTEM_INODE,
                        slot_num);
     if (!inode) {
         status = -EINVAL;
         mlog(ML_ERROR, "Could not get load truncate log inode!\n");
         goto bail;
     }
 
     status = ocfs2_read_inode_block(inode, &bh);
     if (status < 0) {
         iput(inode);
         mlog_errno(status);
         goto bail;
     }
 
     *tl_inode = inode;
     *tl_bh    = bh;
 bail:
     return status;
 }
 
 /* called during the 1st stage of node recovery. we stamp a clean
  * truncate log and pass back a copy for processing later. if the
  * truncate log does not require processing, a *tl_copy is set to
  * NULL. */
 int ocfs2_begin_truncate_log_recovery(struct ocfs2_super *osb,
                       int slot_num,
                       struct ocfs2_dinode **tl_copy)
 {
     int status;
     struct inode *tl_inode = NULL;
     struct buffer_head *tl_bh = NULL;
     struct ocfs2_dinode *di;
     struct ocfs2_truncate_log *tl;
 
     *tl_copy = NULL;
 
     trace_ocfs2_begin_truncate_log_recovery(slot_num);
 
     status = ocfs2_get_truncate_log_info(osb, slot_num, &tl_inode, &tl_bh);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     di = (struct ocfs2_dinode *) tl_bh->b_data;
 
     /* tl_bh is loaded from ocfs2_get_truncate_log_info().  It's
      * validated by the underlying call to ocfs2_read_inode_block(),
      * so any corruption is a code bug */
     BUG_ON(!OCFS2_IS_VALID_DINODE(di));
 
     tl = &di->id2.i_dealloc;
     if (le16_to_cpu(tl->tl_used)) {
         trace_ocfs2_truncate_log_recovery_num(le16_to_cpu(tl->tl_used));
 
         /*
          * Assuming the write-out below goes well, this copy will be
          * passed back to recovery for processing.
          */
         *tl_copy = kmemdup(tl_bh->b_data, tl_bh->b_size, GFP_KERNEL);
         if (!(*tl_copy)) {
             status = -ENOMEM;
             mlog_errno(status);
             goto bail;
         }
 
         /* All we need to do to clear the truncate log is set
          * tl_used. */
         tl->tl_used = 0;
 
         ocfs2_compute_meta_ecc(osb->sb, tl_bh->b_data, &di->i_check);
         status = ocfs2_write_block(osb, tl_bh, INODE_CACHE(tl_inode));
         if (status < 0) {
             mlog_errno(status);
             goto bail;
         }
     }
 
 bail:
     iput(tl_inode);
     brelse(tl_bh);
 
     if (status < 0) {
         kfree(*tl_copy);
         *tl_copy = NULL;
         mlog_errno(status);
     }
 
     return status;
 }
 
 int ocfs2_complete_truncate_log_recovery(struct ocfs2_super *osb,
                      struct ocfs2_dinode *tl_copy)
 {
     int status = 0;
     int i;
     unsigned int clusters, num_recs, start_cluster;
     u64 start_blk;
     handle_t *handle;
     struct inode *tl_inode = osb->osb_tl_inode;
     struct ocfs2_truncate_log *tl;
 
     if (OCFS2_I(tl_inode)->ip_blkno == le64_to_cpu(tl_copy->i_blkno)) {
         mlog(ML_ERROR, "Asked to recover my own truncate log!\n");
         return -EINVAL;
     }
 
     tl = &tl_copy->id2.i_dealloc;
     num_recs = le16_to_cpu(tl->tl_used);
     trace_ocfs2_complete_truncate_log_recovery(
         (unsigned long long)le64_to_cpu(tl_copy->i_blkno),
         num_recs);
 
     inode_lock(tl_inode);
     for(i = 0; i < num_recs; i++) {
         if (ocfs2_truncate_log_needs_flush(osb)) {
             status = __ocfs2_flush_truncate_log(osb);
             if (status < 0) {
                 mlog_errno(status);
                 goto bail_up;
             }
         }
 
         handle = ocfs2_start_trans(osb, OCFS2_TRUNCATE_LOG_UPDATE);
         if (IS_ERR(handle)) {
             status = PTR_ERR(handle);
             mlog_errno(status);
             goto bail_up;
         }
 
         clusters = le32_to_cpu(tl->tl_recs[i].t_clusters);
         start_cluster = le32_to_cpu(tl->tl_recs[i].t_start);
         start_blk = ocfs2_clusters_to_blocks(osb->sb, start_cluster);
 
         status = ocfs2_truncate_log_append(osb, handle,
                            start_blk, clusters);
         ocfs2_commit_trans(osb, handle);
         if (status < 0) {
             mlog_errno(status);
             goto bail_up;
         }
     }
 
 bail_up:
     inode_unlock(tl_inode);
 
     return status;
 }
 
 void ocfs2_truncate_log_shutdown(struct ocfs2_super *osb)
 {
     int status;
     struct inode *tl_inode = osb->osb_tl_inode;
 
     atomic_set(&osb->osb_tl_disable, 1);
 
     if (tl_inode) {
         cancel_delayed_work(&osb->osb_truncate_log_wq);
         flush_workqueue(osb->ocfs2_wq);
 
         status = ocfs2_flush_truncate_log(osb);
         if (status < 0)
             mlog_errno(status);
 
         brelse(osb->osb_tl_bh);
         iput(osb->osb_tl_inode);
     }
 }
 
 int ocfs2_truncate_log_init(struct ocfs2_super *osb)
 {
     int status;
     struct inode *tl_inode = NULL;
     struct buffer_head *tl_bh = NULL;
 
     status = ocfs2_get_truncate_log_info(osb,
                          osb->slot_num,
                          &tl_inode,
                          &tl_bh);
     if (status < 0)
         mlog_errno(status);
 
     /* ocfs2_truncate_log_shutdown keys on the existence of
      * osb->osb_tl_inode so we don't set any of the osb variables
      * until we're sure all is well. */
     INIT_DELAYED_WORK(&osb->osb_truncate_log_wq,
               ocfs2_truncate_log_worker);
     atomic_set(&osb->osb_tl_disable, 0);
     osb->osb_tl_bh    = tl_bh;
     osb->osb_tl_inode = tl_inode;
 
     return status;
 }
 
 /*
  * Delayed de-allocation of suballocator blocks.
  *
  * Some sets of block de-allocations might involve multiple suballocator inodes.
  *
  * The locking for this can get extremely complicated, especially when
  * the suballocator inodes to delete from aren't known until deep
  * within an unrelated codepath.
  *
  * ocfs2_extent_block structures are a good example of this - an inode
  * btree could have been grown by any number of nodes each allocating
  * out of their own suballoc inode.
  *
  * These structures allow the delay of block de-allocation until a
  * later time, when locking of multiple cluster inodes won't cause
  * deadlock.
  */
 
 /*
  * Describe a single bit freed from a suballocator.  For the block
  * suballocators, it represents one block.  For the global cluster
  * allocator, it represents some clusters and free_bit indicates
  * clusters number.
  */
 struct ocfs2_cached_block_free {
     struct ocfs2_cached_block_free      *free_next;
     u64                 free_bg;
     u64                 free_blk;
     unsigned int                free_bit;
 };
 
 struct ocfs2_per_slot_free_list {
     struct ocfs2_per_slot_free_list     *f_next_suballocator;
     int                 f_inode_type;
     int                 f_slot;
     struct ocfs2_cached_block_free      *f_first;
 };
 
 static int ocfs2_free_cached_blocks(struct ocfs2_super *osb,
                     int sysfile_type,
                     int slot,
                     struct ocfs2_cached_block_free *head)
 {
     int ret;
     u64 bg_blkno;
     handle_t *handle;
     struct inode *inode;
     struct buffer_head *di_bh = NULL;
     struct ocfs2_cached_block_free *tmp;
 
     inode = ocfs2_get_system_file_inode(osb, sysfile_type, slot);
     if (!inode) {
         ret = -EINVAL;
         mlog_errno(ret);
         goto out;
     }
 
     inode_lock(inode);
 
     ret = ocfs2_inode_lock(inode, &di_bh, 1);
     if (ret) {
         mlog_errno(ret);
         goto out_mutex;
     }
 
     while (head) {
         if (head->free_bg)
             bg_blkno = head->free_bg;
         else
             bg_blkno = ocfs2_which_suballoc_group(head->free_blk,
                                   head->free_bit);
         handle = ocfs2_start_trans(osb, OCFS2_SUBALLOC_FREE);
         if (IS_ERR(handle)) {
             ret = PTR_ERR(handle);
             mlog_errno(ret);
             goto out_unlock;
         }
 
         trace_ocfs2_free_cached_blocks(
              (unsigned long long)head->free_blk, head->free_bit);
 
         ret = ocfs2_free_suballoc_bits(handle, inode, di_bh,
                            head->free_bit, bg_blkno, 1);
         if (ret)
             mlog_errno(ret);
 
         ocfs2_commit_trans(osb, handle);
 
         tmp = head;
         head = head->free_next;
         kfree(tmp);
     }
 
 out_unlock:
     ocfs2_inode_unlock(inode, 1);
     brelse(di_bh);
 out_mutex:
     inode_unlock(inode);
     iput(inode);
 out:
     while(head) {
         /* Premature exit may have left some dangling items. */
         tmp = head;
         head = head->free_next;
         kfree(tmp);
     }
 
     return ret;
 }
 
 int ocfs2_cache_cluster_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
                 u64 blkno, unsigned int bit)
 {
     int ret = 0;
     struct ocfs2_cached_block_free *item;
 
     item = kzalloc(sizeof(*item), GFP_NOFS);
     if (item == NULL) {
         ret = -ENOMEM;
         mlog_errno(ret);
         return ret;
     }
 
     trace_ocfs2_cache_cluster_dealloc((unsigned long long)blkno, bit);
 
     item->free_blk = blkno;
     item->free_bit = bit;
     item->free_next = ctxt->c_global_allocator;
 
     ctxt->c_global_allocator = item;
     return ret;
 }
 
 static int ocfs2_free_cached_clusters(struct ocfs2_super *osb,
                       struct ocfs2_cached_block_free *head)
 {
     struct ocfs2_cached_block_free *tmp;
     struct inode *tl_inode = osb->osb_tl_inode;
     handle_t *handle;
     int ret = 0;
 
     inode_lock(tl_inode);
 
     while (head) {
         if (ocfs2_truncate_log_needs_flush(osb)) {
             ret = __ocfs2_flush_truncate_log(osb);
             if (ret < 0) {
                 mlog_errno(ret);
                 break;
             }
         }
 
         handle = ocfs2_start_trans(osb, OCFS2_TRUNCATE_LOG_UPDATE);
         if (IS_ERR(handle)) {
             ret = PTR_ERR(handle);
             mlog_errno(ret);
             break;
         }
 
         ret = ocfs2_truncate_log_append(osb, handle, head->free_blk,
                         head->free_bit);
 
         ocfs2_commit_trans(osb, handle);
         tmp = head;
         head = head->free_next;
         kfree(tmp);
 
         if (ret < 0) {
             mlog_errno(ret);
             break;
         }
     }
 
     inode_unlock(tl_inode);
 
     while (head) {
         /* Premature exit may have left some dangling items. */
         tmp = head;
         head = head->free_next;
         kfree(tmp);
     }
 
     return ret;
 }
 
 int ocfs2_run_deallocs(struct ocfs2_super *osb,
                struct ocfs2_cached_dealloc_ctxt *ctxt)
 {
     int ret = 0, ret2;
     struct ocfs2_per_slot_free_list *fl;
 
     if (!ctxt)
         return 0;
 
     while (ctxt->c_first_suballocator) {
         fl = ctxt->c_first_suballocator;
 
         if (fl->f_first) {
             trace_ocfs2_run_deallocs(fl->f_inode_type,
                          fl->f_slot);
             ret2 = ocfs2_free_cached_blocks(osb,
                             fl->f_inode_type,
                             fl->f_slot,
                             fl->f_first);
             if (ret2)
                 mlog_errno(ret2);
             if (!ret)
                 ret = ret2;
         }
 
         ctxt->c_first_suballocator = fl->f_next_suballocator;
         kfree(fl);
     }
 
     if (ctxt->c_global_allocator) {
         ret2 = ocfs2_free_cached_clusters(osb,
                           ctxt->c_global_allocator);
         if (ret2)
             mlog_errno(ret2);
         if (!ret)
             ret = ret2;
 
         ctxt->c_global_allocator = NULL;
     }
 
     return ret;
 }
 
 static struct ocfs2_per_slot_free_list *
 ocfs2_find_per_slot_free_list(int type,
                   int slot,
                   struct ocfs2_cached_dealloc_ctxt *ctxt)
 {
     struct ocfs2_per_slot_free_list *fl = ctxt->c_first_suballocator;
 
     while (fl) {
         if (fl->f_inode_type == type && fl->f_slot == slot)
             return fl;
 
         fl = fl->f_next_suballocator;
     }
 
     fl = kmalloc(sizeof(*fl), GFP_NOFS);
     if (fl) {
         fl->f_inode_type = type;
         fl->f_slot = slot;
         fl->f_first = NULL;
         fl->f_next_suballocator = ctxt->c_first_suballocator;
 
         ctxt->c_first_suballocator = fl;
     }
     return fl;
 }
 
 static struct ocfs2_per_slot_free_list *
 ocfs2_find_preferred_free_list(int type,
                    int preferred_slot,
                    int *real_slot,
                    struct ocfs2_cached_dealloc_ctxt *ctxt)
 {
     struct ocfs2_per_slot_free_list *fl = ctxt->c_first_suballocator;
 
     while (fl) {
         if (fl->f_inode_type == type && fl->f_slot == preferred_slot) {
             *real_slot = fl->f_slot;
             return fl;
         }
 
         fl = fl->f_next_suballocator;
     }
 
     /* If we can't find any free list matching preferred slot, just use
      * the first one.
      */
     fl = ctxt->c_first_suballocator;
     *real_slot = fl->f_slot;
 
     return fl;
 }
 
 /* Return Value 1 indicates empty */
 static int ocfs2_is_dealloc_empty(struct ocfs2_extent_tree *et)
 {
     struct ocfs2_per_slot_free_list *fl = NULL;
 
     if (!et->et_dealloc)
         return 1;
 
     fl = et->et_dealloc->c_first_suballocator;
     if (!fl)
         return 1;
 
     if (!fl->f_first)
         return 1;
 
     return 0;
 }
 
 /* If extent was deleted from tree due to extent rotation and merging, and
  * no metadata is reserved ahead of time. Try to reuse some extents
  * just deleted. This is only used to reuse extent blocks.
  * It is supposed to find enough extent blocks in dealloc if our estimation
  * on metadata is accurate.
  */
 static int ocfs2_reuse_blk_from_dealloc(handle_t *handle,
                     struct ocfs2_extent_tree *et,
                     struct buffer_head **new_eb_bh,
                     int blk_wanted, int *blk_given)
 {
     int i, status = 0, real_slot;
     struct ocfs2_cached_dealloc_ctxt *dealloc;
     struct ocfs2_per_slot_free_list *fl;
     struct ocfs2_cached_block_free *bf;
     struct ocfs2_extent_block *eb;
     struct ocfs2_super *osb =
         OCFS2_SB(ocfs2_metadata_cache_get_super(et->et_ci));
 
     *blk_given = 0;
 
     /* If extent tree doesn't have a dealloc, this is not faulty. Just
      * tell upper caller dealloc can't provide any block and it should
      * ask for alloc to claim more space.
      */
     dealloc = et->et_dealloc;
     if (!dealloc)
         goto bail;
 
     for (i = 0; i < blk_wanted; i++) {
         /* Prefer to use local slot */
         fl = ocfs2_find_preferred_free_list(EXTENT_ALLOC_SYSTEM_INODE,
                             osb->slot_num, &real_slot,
                             dealloc);
         /* If no more block can be reused, we should claim more
          * from alloc. Just return here normally.
          */
         if (!fl) {
             status = 0;
             break;
         }
 
         bf = fl->f_first;
         fl->f_first = bf->free_next;
 
         new_eb_bh[i] = sb_getblk(osb->sb, bf->free_blk);
         if (new_eb_bh[i] == NULL) {
             status = -ENOMEM;
             mlog_errno(status);
             goto bail;
         }
 
         mlog(0, "Reusing block(%llu) from "
              "dealloc(local slot:%d, real slot:%d)\n",
              bf->free_blk, osb->slot_num, real_slot);
 
         ocfs2_set_new_buffer_uptodate(et->et_ci, new_eb_bh[i]);
 
         status = ocfs2_journal_access_eb(handle, et->et_ci,
                          new_eb_bh[i],
                          OCFS2_JOURNAL_ACCESS_CREATE);
         if (status < 0) {
             mlog_errno(status);
             goto bail;
         }
 
         memset(new_eb_bh[i]->b_data, 0, osb->sb->s_blocksize);
         eb = (struct ocfs2_extent_block *) new_eb_bh[i]->b_data;
 
         /* We can't guarantee that buffer head is still cached, so
          * polutlate the extent block again.
          */
         strcpy(eb->h_signature, OCFS2_EXTENT_BLOCK_SIGNATURE);
         eb->h_blkno = cpu_to_le64(bf->free_blk);
         eb->h_fs_generation = cpu_to_le32(osb->fs_generation);
         eb->h_suballoc_slot = cpu_to_le16(real_slot);
         eb->h_suballoc_loc = cpu_to_le64(bf->free_bg);
         eb->h_suballoc_bit = cpu_to_le16(bf->free_bit);
         eb->h_list.l_count =
             cpu_to_le16(ocfs2_extent_recs_per_eb(osb->sb));
 
         /* We'll also be dirtied by the caller, so
          * this isn't absolutely necessary.
          */
         ocfs2_journal_dirty(handle, new_eb_bh[i]);
 
         if (!fl->f_first) {
             dealloc->c_first_suballocator = fl->f_next_suballocator;
             kfree(fl);
         }
         kfree(bf);
     }
 
     *blk_given = i;
 
 bail:
     if (unlikely(status < 0)) {
         for (i = 0; i < blk_wanted; i++)
             brelse(new_eb_bh[i]);
     }
 
     return status;
 }
 
 int ocfs2_cache_block_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
                   int type, int slot, u64 suballoc,
                   u64 blkno, unsigned int bit)
 {
     int ret;
     struct ocfs2_per_slot_free_list *fl;
     struct ocfs2_cached_block_free *item;
 
     fl = ocfs2_find_per_slot_free_list(type, slot, ctxt);
     if (fl == NULL) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     item = kzalloc(sizeof(*item), GFP_NOFS);
     if (item == NULL) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     trace_ocfs2_cache_block_dealloc(type, slot,
                     (unsigned long long)suballoc,
                     (unsigned long long)blkno, bit);
 
     item->free_bg = suballoc;
     item->free_blk = blkno;
     item->free_bit = bit;
     item->free_next = fl->f_first;
 
     fl->f_first = item;
 
     ret = 0;
 out:
     return ret;
 }
 
 static int ocfs2_cache_extent_block_free(struct ocfs2_cached_dealloc_ctxt *ctxt,
                      struct ocfs2_extent_block *eb)
 {
     return ocfs2_cache_block_dealloc(ctxt, EXTENT_ALLOC_SYSTEM_INODE,
                      le16_to_cpu(eb->h_suballoc_slot),
                      le64_to_cpu(eb->h_suballoc_loc),
                      le64_to_cpu(eb->h_blkno),
                      le16_to_cpu(eb->h_suballoc_bit));
 }
 
 static int ocfs2_zero_func(handle_t *handle, struct buffer_head *bh)
 {
     set_buffer_uptodate(bh);
     mark_buffer_dirty(bh);
     return 0;
 }
 
 void ocfs2_map_and_dirty_page(struct inode *inode, handle_t *handle,
                   unsigned int from, unsigned int to,
                   struct page *page, int zero, u64 *phys)
 {
     int ret, partial = 0;
     loff_t start_byte = ((loff_t)page->index << PAGE_SHIFT) + from;
     loff_t length = to - from;
 
     ret = ocfs2_map_page_blocks(page, phys, inode, from, to, 0);
     if (ret)
         mlog_errno(ret);
 
     if (zero)
         zero_user_segment(page, from, to);
 
     /*
      * Need to set the buffers we zero'd into uptodate
      * here if they aren't - ocfs2_map_page_blocks()
      * might've skipped some
      */
     ret = walk_page_buffers(handle, page_buffers(page),
                 from, to, &partial,
                 ocfs2_zero_func);
     if (ret < 0)
         mlog_errno(ret);
     else if (ocfs2_should_order_data(inode)) {
         ret = ocfs2_jbd2_inode_add_write(handle, inode,
                          start_byte, length);
         if (ret < 0)
             mlog_errno(ret);
     }
 
     if (!partial)
         SetPageUptodate(page);
 
     flush_dcache_page(page);
 }
 
 static void ocfs2_zero_cluster_pages(struct inode *inode, loff_t start,
                      loff_t end, struct page **pages,
                      int numpages, u64 phys, handle_t *handle)
 {
     int i;
     struct page *page;
     unsigned int from, to = PAGE_SIZE;
     struct super_block *sb = inode->i_sb;
 
     BUG_ON(!ocfs2_sparse_alloc(OCFS2_SB(sb)));
 
     if (numpages == 0)
         goto out;
 
     to = PAGE_SIZE;
     for(i = 0; i < numpages; i++) {
         page = pages[i];
 
         from = start & (PAGE_SIZE - 1);
         if ((end >> PAGE_SHIFT) == page->index)
             to = end & (PAGE_SIZE - 1);
 
         BUG_ON(from > PAGE_SIZE);
         BUG_ON(to > PAGE_SIZE);
 
         ocfs2_map_and_dirty_page(inode, handle, from, to, page, 1,
                      &phys);
 
         start = (page->index + 1) << PAGE_SHIFT;
     }
 out:
     if (pages)
         ocfs2_unlock_and_free_pages(pages, numpages);
 }
 
 int ocfs2_grab_pages(struct inode *inode, loff_t start, loff_t end,
              struct page **pages, int *num)
 {
     int numpages, ret = 0;
     struct address_space *mapping = inode->i_mapping;
     unsigned long index;
     loff_t last_page_bytes;
 
     BUG_ON(start > end);
 
     numpages = 0;
     last_page_bytes = PAGE_ALIGN(end);
     index = start >> PAGE_SHIFT;
     do {
         pages[numpages] = find_or_create_page(mapping, index, GFP_NOFS);
         if (!pages[numpages]) {
             ret = -ENOMEM;
             mlog_errno(ret);
             goto out;
         }
 
         numpages++;
         index++;
     } while (index < (last_page_bytes >> PAGE_SHIFT));
 
 out:
     if (ret != 0) {
         if (pages)
             ocfs2_unlock_and_free_pages(pages, numpages);
         numpages = 0;
     }
 
     *num = numpages;
 
     return ret;
 }
 
 static int ocfs2_grab_eof_pages(struct inode *inode, loff_t start, loff_t end,
                 struct page **pages, int *num)
 {
     struct super_block *sb = inode->i_sb;
 
     BUG_ON(start >> OCFS2_SB(sb)->s_clustersize_bits !=
            (end - 1) >> OCFS2_SB(sb)->s_clustersize_bits);
 
     return ocfs2_grab_pages(inode, start, end, pages, num);
 }
 
 /*
  * Zero partial cluster for a hole punch or truncate. This avoids exposing
  * nonzero data on subsequent file extends.
  *
  * We need to call this before i_size is updated on the inode because
  * otherwise block_write_full_page() will skip writeout of pages past
  * i_size.
  */
 int ocfs2_zero_range_for_truncate(struct inode *inode, handle_t *handle,
                   u64 range_start, u64 range_end)
 {
     int ret = 0, numpages;
     struct page **pages = NULL;
     u64 phys;
     unsigned int ext_flags;
     struct super_block *sb = inode->i_sb;
 
     /*
      * File systems which don't support sparse files zero on every
      * extend.
      */
     if (!ocfs2_sparse_alloc(OCFS2_SB(sb)))
         return 0;
 
     /*
      * Avoid zeroing pages fully beyond current i_size. It is pointless as
      * underlying blocks of those pages should be already zeroed out and
      * page writeback will skip them anyway.
      */
     range_end = min_t(u64, range_end, i_size_read(inode));
     if (range_start >= range_end)
         return 0;
 
     pages = kcalloc(ocfs2_pages_per_cluster(sb),
             sizeof(struct page *), GFP_NOFS);
     if (pages == NULL) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_extent_map_get_blocks(inode,
                       range_start >> sb->s_blocksize_bits,
                       &phys, NULL, &ext_flags);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     /*
      * Tail is a hole, or is marked unwritten. In either case, we
      * can count on read and write to return/push zero's.
      */
     if (phys == 0 || ext_flags & OCFS2_EXT_UNWRITTEN)
         goto out;
 
     ret = ocfs2_grab_eof_pages(inode, range_start, range_end, pages,
                    &numpages);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     ocfs2_zero_cluster_pages(inode, range_start, range_end, pages,
                  numpages, phys, handle);
 
     /*
      * Initiate writeout of the pages we zero'd here. We don't
      * wait on them - the truncate_inode_pages() call later will
      * do that for us.
      */
     ret = filemap_fdatawrite_range(inode->i_mapping, range_start,
                        range_end - 1);
     if (ret)
         mlog_errno(ret);
 
 out:
     kfree(pages);
 
     return ret;
 }
 
 static void ocfs2_zero_dinode_id2_with_xattr(struct inode *inode,
                          struct ocfs2_dinode *di)
 {
     unsigned int blocksize = 1 << inode->i_sb->s_blocksize_bits;
     unsigned int xattrsize = le16_to_cpu(di->i_xattr_inline_size);
 
     if (le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_XATTR_FL)
         memset(&di->id2, 0, blocksize -
                     offsetof(struct ocfs2_dinode, id2) -
                     xattrsize);
     else
         memset(&di->id2, 0, blocksize -
                     offsetof(struct ocfs2_dinode, id2));
 }
 
 void ocfs2_dinode_new_extent_list(struct inode *inode,
                   struct ocfs2_dinode *di)
 {
     ocfs2_zero_dinode_id2_with_xattr(inode, di);
     di->id2.i_list.l_tree_depth = 0;
     di->id2.i_list.l_next_free_rec = 0;
     di->id2.i_list.l_count = cpu_to_le16(
         ocfs2_extent_recs_per_inode_with_xattr(inode->i_sb, di));
 }
 
 void ocfs2_set_inode_data_inline(struct inode *inode, struct ocfs2_dinode *di)
 {
     struct ocfs2_inode_info *oi = OCFS2_I(inode);
     struct ocfs2_inline_data *idata = &di->id2.i_data;
 
     spin_lock(&oi->ip_lock);
     oi->ip_dyn_features |= OCFS2_INLINE_DATA_FL;
     di->i_dyn_features = cpu_to_le16(oi->ip_dyn_features);
     spin_unlock(&oi->ip_lock);
 
     /*
      * We clear the entire i_data structure here so that all
      * fields can be properly initialized.
      */
     ocfs2_zero_dinode_id2_with_xattr(inode, di);
 
     idata->id_count = cpu_to_le16(
             ocfs2_max_inline_data_with_xattr(inode->i_sb, di));
 }
 
 int ocfs2_convert_inline_data_to_extents(struct inode *inode,
                      struct buffer_head *di_bh)
 {
     int ret, has_data, num_pages = 0;
     int need_free = 0;
     u32 bit_off, num;
     handle_t *handle;
     u64 block;
     struct ocfs2_inode_info *oi = OCFS2_I(inode);
     struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
     struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
     struct ocfs2_alloc_context *data_ac = NULL;
     struct page *page = NULL;
     struct ocfs2_extent_tree et;
     int did_quota = 0;
 
     has_data = i_size_read(inode) ? 1 : 0;
 
     if (has_data) {
         ret = ocfs2_reserve_clusters(osb, 1, &data_ac);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     handle = ocfs2_start_trans(osb,
                    ocfs2_inline_to_extents_credits(osb->sb));
     if (IS_ERR(handle)) {
         ret = PTR_ERR(handle);
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
                       OCFS2_JOURNAL_ACCESS_WRITE);
     if (ret) {
         mlog_errno(ret);
         goto out_commit;
     }
 
     if (has_data) {
         unsigned int page_end = min_t(unsigned, PAGE_SIZE,
                             osb->s_clustersize);
         u64 phys;
 
         ret = dquot_alloc_space_nodirty(inode,
                        ocfs2_clusters_to_bytes(osb->sb, 1));
         if (ret)
             goto out_commit;
         did_quota = 1;
 
         data_ac->ac_resv = &oi->ip_la_data_resv;
 
         ret = ocfs2_claim_clusters(handle, data_ac, 1, &bit_off,
                        &num);
         if (ret) {
             mlog_errno(ret);
             goto out_commit;
         }
 
         /*
          * Save two copies, one for insert, and one that can
          * be changed by ocfs2_map_and_dirty_page() below.
          */
         block = phys = ocfs2_clusters_to_blocks(inode->i_sb, bit_off);
 
         ret = ocfs2_grab_eof_pages(inode, 0, page_end, &page,
                        &num_pages);
         if (ret) {
             mlog_errno(ret);
             need_free = 1;
             goto out_commit;
         }
 
         /*
          * This should populate the 1st page for us and mark
          * it up to date.
          */
         ret = ocfs2_read_inline_data(inode, page, di_bh);
         if (ret) {
             mlog_errno(ret);
             need_free = 1;
             goto out_unlock;
         }
 
         ocfs2_map_and_dirty_page(inode, handle, 0, page_end, page, 0,
                      &phys);
     }
 
     spin_lock(&oi->ip_lock);
     oi->ip_dyn_features &= ~OCFS2_INLINE_DATA_FL;
     di->i_dyn_features = cpu_to_le16(oi->ip_dyn_features);
     spin_unlock(&oi->ip_lock);
 
     ocfs2_update_inode_fsync_trans(handle, inode, 1);
     ocfs2_dinode_new_extent_list(inode, di);
 
     ocfs2_journal_dirty(handle, di_bh);
 
     if (has_data) {
         /*
          * An error at this point should be extremely rare. If
          * this proves to be false, we could always re-build
          * the in-inode data from our pages.
          */
         ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), di_bh);
         ret = ocfs2_insert_extent(handle, &et, 0, block, 1, 0, NULL);
         if (ret) {
             mlog_errno(ret);
             need_free = 1;
             goto out_unlock;
         }
 
         inode->i_blocks = ocfs2_inode_sector_count(inode);
     }
 
 out_unlock:
     if (page)
         ocfs2_unlock_and_free_pages(&page, num_pages);
 
 out_commit:
     if (ret < 0 && did_quota)
         dquot_free_space_nodirty(inode,
                       ocfs2_clusters_to_bytes(osb->sb, 1));
 
     if (need_free) {
         if (data_ac->ac_which == OCFS2_AC_USE_LOCAL)
             ocfs2_free_local_alloc_bits(osb, handle, data_ac,
                     bit_off, num);
         else
             ocfs2_free_clusters(handle,
                     data_ac->ac_inode,
                     data_ac->ac_bh,
                     ocfs2_clusters_to_blocks(osb->sb, bit_off),
                     num);
     }
 
     ocfs2_commit_trans(osb, handle);
 
 out:
     if (data_ac)
         ocfs2_free_alloc_context(data_ac);
     return ret;
 }
 
 /*
  * It is expected, that by the time you call this function,
  * inode->i_size and fe->i_size have been adjusted.
  *
  * WARNING: This will kfree the truncate context
  */
 int ocfs2_commit_truncate(struct ocfs2_super *osb,
               struct inode *inode,
               struct buffer_head *di_bh)
 {
     int status = 0, i, flags = 0;
     u32 new_highest_cpos, range, trunc_cpos, trunc_len, phys_cpos, coff;
     u64 blkno = 0;
     struct ocfs2_extent_list *el;
     struct ocfs2_extent_rec *rec;
     struct ocfs2_path *path = NULL;
     struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
     struct ocfs2_extent_list *root_el = &(di->id2.i_list);
     u64 refcount_loc = le64_to_cpu(di->i_refcount_loc);
     struct ocfs2_extent_tree et;
     struct ocfs2_cached_dealloc_ctxt dealloc;
     struct ocfs2_refcount_tree *ref_tree = NULL;
 
     ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), di_bh);
     ocfs2_init_dealloc_ctxt(&dealloc);
 
     new_highest_cpos = ocfs2_clusters_for_bytes(osb->sb,
                              i_size_read(inode));
 
     path = ocfs2_new_path(di_bh, &di->id2.i_list,
                   ocfs2_journal_access_di);
     if (!path) {
         status = -ENOMEM;
         mlog_errno(status);
         goto bail;
     }
 
     ocfs2_extent_map_trunc(inode, new_highest_cpos);
 
 start:
     /*
      * Check that we still have allocation to delete.
      */
     if (OCFS2_I(inode)->ip_clusters == 0) {
         status = 0;
         goto bail;
     }
 
     /*
      * Truncate always works against the rightmost tree branch.
      */
     status = ocfs2_find_path(INODE_CACHE(inode), path, UINT_MAX);
     if (status) {
         mlog_errno(status);
         goto bail;
     }
 
     trace_ocfs2_commit_truncate(
         (unsigned long long)OCFS2_I(inode)->ip_blkno,
         new_highest_cpos,
         OCFS2_I(inode)->ip_clusters,
         path->p_tree_depth);
 
     /*
      * By now, el will point to the extent list on the bottom most
      * portion of this tree. Only the tail record is considered in
      * each pass.
      *
      * We handle the following cases, in order:
      * - empty extent: delete the remaining branch
      * - remove the entire record
      * - remove a partial record
      * - no record needs to be removed (truncate has completed)
      */
     el = path_leaf_el(path);
     if (le16_to_cpu(el->l_next_free_rec) == 0) {
         ocfs2_error(inode->i_sb,
                 "Inode %llu has empty extent block at %llu\n",
                 (unsigned long long)OCFS2_I(inode)->ip_blkno,
                 (unsigned long long)path_leaf_bh(path)->b_blocknr);
         status = -EROFS;
         goto bail;
     }
 
     i = le16_to_cpu(el->l_next_free_rec) - 1;
     rec = &el->l_recs[i];
     flags = rec->e_flags;
     range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
 
     if (i == 0 && ocfs2_is_empty_extent(rec)) {
         /*
          * Lower levels depend on this never happening, but it's best
          * to check it up here before changing the tree.
         */
         if (root_el->l_tree_depth && rec->e_int_clusters == 0) {
             mlog(ML_ERROR, "Inode %lu has an empty "
                     "extent record, depth %u\n", inode->i_ino,
                     le16_to_cpu(root_el->l_tree_depth));
             status = ocfs2_remove_rightmost_empty_extent(osb,
                     &et, path, &dealloc);
             if (status) {
                 mlog_errno(status);
                 goto bail;
             }
 
             ocfs2_reinit_path(path, 1);
             goto start;
         } else {
             trunc_cpos = le32_to_cpu(rec->e_cpos);
             trunc_len = 0;
             blkno = 0;
         }
     } else if (le32_to_cpu(rec->e_cpos) >= new_highest_cpos) {
         /*
          * Truncate entire record.
          */
         trunc_cpos = le32_to_cpu(rec->e_cpos);
         trunc_len = ocfs2_rec_clusters(el, rec);
         blkno = le64_to_cpu(rec->e_blkno);
     } else if (range > new_highest_cpos) {
         /*
          * Partial truncate. it also should be
          * the last truncate we're doing.
          */
         trunc_cpos = new_highest_cpos;
         trunc_len = range - new_highest_cpos;
         coff = new_highest_cpos - le32_to_cpu(rec->e_cpos);
         blkno = le64_to_cpu(rec->e_blkno) +
                 ocfs2_clusters_to_blocks(inode->i_sb, coff);
     } else {
         /*
          * Truncate completed, leave happily.
          */
         status = 0;
         goto bail;
     }
 
     phys_cpos = ocfs2_blocks_to_clusters(inode->i_sb, blkno);
 
     if ((flags & OCFS2_EXT_REFCOUNTED) && trunc_len && !ref_tree) {
         status = ocfs2_lock_refcount_tree(osb, refcount_loc, 1,
                 &ref_tree, NULL);
         if (status) {
             mlog_errno(status);
             goto bail;
         }
     }
 
     status = ocfs2_remove_btree_range(inode, &et, trunc_cpos,
                       phys_cpos, trunc_len, flags, &dealloc,
                       refcount_loc, true);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     ocfs2_reinit_path(path, 1);
 
     /*
      * The check above will catch the case where we've truncated
      * away all allocation.
      */
     goto start;
 
 bail:
     if (ref_tree)
         ocfs2_unlock_refcount_tree(osb, ref_tree, 1);
 
     ocfs2_schedule_truncate_log_flush(osb, 1);
 
     ocfs2_run_deallocs(osb, &dealloc);
 
     ocfs2_free_path(path);
 
     return status;
 }
 
 /*
  * 'start' is inclusive, 'end' is not.
  */
 int ocfs2_truncate_inline(struct inode *inode, struct buffer_head *di_bh,
               unsigned int start, unsigned int end, int trunc)
 {
     int ret;
     unsigned int numbytes;
     handle_t *handle;
     struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
     struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
     struct ocfs2_inline_data *idata = &di->id2.i_data;
 
     /* No need to punch hole beyond i_size. */
     if (start >= i_size_read(inode))
         return 0;
 
     if (end > i_size_read(inode))
         end = i_size_read(inode);
 
     BUG_ON(start > end);
 
     if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
         !(le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_DATA_FL) ||
         !ocfs2_supports_inline_data(osb)) {
         ocfs2_error(inode->i_sb,
                 "Inline data flags for inode %llu don't agree! Disk: 0x%x, Memory: 0x%x, Superblock: 0x%x\n",
                 (unsigned long long)OCFS2_I(inode)->ip_blkno,
                 le16_to_cpu(di->i_dyn_features),
                 OCFS2_I(inode)->ip_dyn_features,
                 osb->s_feature_incompat);
         ret = -EROFS;
         goto out;
     }
 
     handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
     if (IS_ERR(handle)) {
         ret = PTR_ERR(handle);
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
                       OCFS2_JOURNAL_ACCESS_WRITE);
     if (ret) {
         mlog_errno(ret);
         goto out_commit;
     }
 
     numbytes = end - start;
     memset(idata->id_data + start, 0, numbytes);
 
     /*
      * No need to worry about the data page here - it's been
      * truncated already and inline data doesn't need it for
      * pushing zero's to disk, so we'll let read_folio pick it up
      * later.
      */
     if (trunc) {
         i_size_write(inode, start);
         di->i_size = cpu_to_le64(start);
     }
 
     inode->i_blocks = ocfs2_inode_sector_count(inode);
     inode->i_ctime = inode->i_mtime = current_time(inode);
 
     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,
                  u64 group, u32 start, u32 count)
 {
     u64 discard, bcount;
     struct ocfs2_super *osb = OCFS2_SB(sb);
 
     bcount = ocfs2_clusters_to_blocks(sb, count);
     discard = ocfs2_clusters_to_blocks(sb, start);
 
     /*
      * For the first cluster group, the gd->bg_blkno is not at the start
      * of the group, but at an offset from the start. If we add it while
      * calculating discard for first group, we will wrongly start fstrim a
      * few blocks after the desried start block and the range can cross
      * over into the next cluster group. So, add it only if this is not
      * the first cluster group.
      */
     if (group != osb->first_cluster_group_blkno)
         discard += le64_to_cpu(gd->bg_blkno);
 
     trace_ocfs2_trim_extent(sb, (unsigned long long)discard, bcount);
 
     return sb_issue_discard(sb, discard, bcount, GFP_NOFS, 0);
 }
 
 static int ocfs2_trim_group(struct super_block *sb,
                 struct ocfs2_group_desc *gd, u64 group,
                 u32 start, u32 max, u32 minbits)
 {
     int ret = 0, count = 0, next;
     void *bitmap = gd->bg_bitmap;
 
     if (le16_to_cpu(gd->bg_free_bits_count) < minbits)
         return 0;
 
     trace_ocfs2_trim_group((unsigned long long)le64_to_cpu(gd->bg_blkno),
                    start, max, minbits);
 
     while (start < max) {
         start = ocfs2_find_next_zero_bit(bitmap, max, start);
         if (start >= max)
             break;
         next = ocfs2_find_next_bit(bitmap, max, start);
 
         if ((next - start) >= minbits) {
             ret = ocfs2_trim_extent(sb, gd, group,
                         start, next - start);
             if (ret < 0) {
                 mlog_errno(ret);
                 break;
             }
             count += next - start;
         }
         start = next + 1;
 
         if (fatal_signal_pending(current)) {
             count = -ERESTARTSYS;
             break;
         }
 
         if ((le16_to_cpu(gd->bg_free_bits_count) - count) < minbits)
             break;
     }
 
     if (ret < 0)
         count = ret;
 
     return count;
 }
 
 static
 int ocfs2_trim_mainbm(struct super_block *sb, struct fstrim_range *range)
 {
     struct ocfs2_super *osb = OCFS2_SB(sb);
     u64 start, len, trimmed = 0, first_group, last_group = 0, group = 0;
     int ret, cnt;
     u32 first_bit, last_bit, minlen;
     struct buffer_head *main_bm_bh = NULL;
     struct inode *main_bm_inode = NULL;
     struct buffer_head *gd_bh = NULL;
     struct ocfs2_dinode *main_bm;
     struct ocfs2_group_desc *gd = NULL;
 
     start = range->start >> osb->s_clustersize_bits;
     len = range->len >> osb->s_clustersize_bits;
     minlen = range->minlen >> osb->s_clustersize_bits;
 
     if (minlen >= osb->bitmap_cpg || range->len < sb->s_blocksize)
         return -EINVAL;
 
     trace_ocfs2_trim_mainbm(start, len, minlen);
 
 next_group:
     main_bm_inode = ocfs2_get_system_file_inode(osb,
                             GLOBAL_BITMAP_SYSTEM_INODE,
                             OCFS2_INVALID_SLOT);
     if (!main_bm_inode) {
         ret = -EIO;
         mlog_errno(ret);
         goto out;
     }
 
     inode_lock(main_bm_inode);
 
     ret = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 0);
     if (ret < 0) {
         mlog_errno(ret);
         goto out_mutex;
     }
     main_bm = (struct ocfs2_dinode *)main_bm_bh->b_data;
 
     /*
      * Do some check before trim the first group.
      */
     if (!group) {
         if (start >= le32_to_cpu(main_bm->i_clusters)) {
             ret = -EINVAL;
             goto out_unlock;
         }
 
         if (start + len > le32_to_cpu(main_bm->i_clusters))
             len = le32_to_cpu(main_bm->i_clusters) - start;
 
         /*
          * Determine first and last group to examine based on
          * start and len
          */
         first_group = ocfs2_which_cluster_group(main_bm_inode, start);
         if (first_group == osb->first_cluster_group_blkno)
             first_bit = start;
         else
             first_bit = start - ocfs2_blocks_to_clusters(sb,
                                 first_group);
         last_group = ocfs2_which_cluster_group(main_bm_inode,
                                start + len - 1);
         group = first_group;
     }
 
     do {
         if (first_bit + len >= osb->bitmap_cpg)
             last_bit = osb->bitmap_cpg;
         else
             last_bit = first_bit + len;
 
         ret = ocfs2_read_group_descriptor(main_bm_inode,
                           main_bm, group,
                           &gd_bh);
         if (ret < 0) {
             mlog_errno(ret);
             break;
         }
 
         gd = (struct ocfs2_group_desc *)gd_bh->b_data;
         cnt = ocfs2_trim_group(sb, gd, group,
                        first_bit, last_bit, minlen);
         brelse(gd_bh);
         gd_bh = NULL;
         if (cnt < 0) {
             ret = cnt;
             mlog_errno(ret);
             break;
         }
 
         trimmed += cnt;
         len -= osb->bitmap_cpg - first_bit;
         first_bit = 0;
         if (group == osb->first_cluster_group_blkno)
             group = ocfs2_clusters_to_blocks(sb, osb->bitmap_cpg);
         else
             group += ocfs2_clusters_to_blocks(sb, osb->bitmap_cpg);
     } while (0);
 
 out_unlock:
     ocfs2_inode_unlock(main_bm_inode, 0);
     brelse(main_bm_bh);
     main_bm_bh = NULL;
 out_mutex:
     inode_unlock(main_bm_inode);
     iput(main_bm_inode);
 
     /*
      * If all the groups trim are not done or failed, but we should release
      * main_bm related locks for avoiding the current IO starve, then go to
      * trim the next group
      */
     if (ret >= 0 && group <= last_group) {
         cond_resched();
         goto next_group;
     }
 out:
     range->len = trimmed * sb->s_blocksize;
     return ret;
 }
 
 int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
 {
     int ret;
     struct ocfs2_super *osb = OCFS2_SB(sb);
     struct ocfs2_trim_fs_info info, *pinfo = NULL;
 
     ocfs2_trim_fs_lock_res_init(osb);
 
     trace_ocfs2_trim_fs(range->start, range->len, range->minlen);
 
     ret = ocfs2_trim_fs_lock(osb, NULL, 1);
     if (ret < 0) {
         if (ret != -EAGAIN) {
             mlog_errno(ret);
             ocfs2_trim_fs_lock_res_uninit(osb);
             return ret;
         }
 
         mlog(ML_NOTICE, "Wait for trim on device (%s) to "
              "finish, which is running from another node.\n",
              osb->dev_str);
         ret = ocfs2_trim_fs_lock(osb, &info, 0);
         if (ret < 0) {
             mlog_errno(ret);
             ocfs2_trim_fs_lock_res_uninit(osb);
             return ret;
         }
 
         if (info.tf_valid && info.tf_success &&
             info.tf_start == range->start &&
             info.tf_len == range->len &&
             info.tf_minlen == range->minlen) {
             /* Avoid sending duplicated trim to a shared device */
             mlog(ML_NOTICE, "The same trim on device (%s) was "
                  "just done from node (%u), return.\n",
                  osb->dev_str, info.tf_nodenum);
             range->len = info.tf_trimlen;
             goto out;
         }
     }
 
     info.tf_nodenum = osb->node_num;
     info.tf_start = range->start;
     info.tf_len = range->len;
     info.tf_minlen = range->minlen;
 
     ret = ocfs2_trim_mainbm(sb, range);
 
     info.tf_trimlen = range->len;
     info.tf_success = (ret < 0 ? 0 : 1);
     pinfo = &info;
 out:
     ocfs2_trim_fs_unlock(osb, pinfo);
     ocfs2_trim_fs_lock_res_uninit(osb);
     return ret;
 }