ocfs2: Remove unused structure field
[cascardo/linux.git] / fs / ocfs2 / alloc.c
index a02d026..c91706f 100644 (file)
@@ -118,6 +118,31 @@ static void ocfs2_free_path(struct ocfs2_path *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));
+
+       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.
@@ -214,10 +239,41 @@ 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;
+}
+
 enum ocfs2_contig_type {
        CONTIG_NONE = 0,
        CONTIG_LEFT,
-       CONTIG_RIGHT
+       CONTIG_RIGHT,
+       CONTIG_LEFTRIGHT,
 };
 
 
@@ -255,6 +311,14 @@ static enum ocfs2_contig_type
 {
        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(inode->i_sb, ext, blkno))
                        return CONTIG_RIGHT;
@@ -279,14 +343,26 @@ enum ocfs2_append_type {
        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_free_records;
        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;
+};
+
 /*
  * How many free extents have we got before we need more meta data?
  */
@@ -457,7 +533,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
                            struct inode *inode,
                            struct buffer_head *fe_bh,
                            struct buffer_head *eb_bh,
-                           struct buffer_head *last_eb_bh,
+                           struct buffer_head **last_eb_bh,
                            struct ocfs2_alloc_context *meta_ac)
 {
        int status, new_blocks, i;
@@ -472,7 +548,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
 
        mlog_entry_void();
 
-       BUG_ON(!last_eb_bh);
+       BUG_ON(!last_eb_bh || !*last_eb_bh);
 
        fe = (struct ocfs2_dinode *) fe_bh->b_data;
 
@@ -503,7 +579,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
                goto bail;
        }
 
-       eb = (struct ocfs2_extent_block *)last_eb_bh->b_data;
+       eb = (struct ocfs2_extent_block *)(*last_eb_bh)->b_data;
        new_cpos = ocfs2_sum_rightmost_rec(&eb->h_list);
 
        /* Note: new_eb_bhs[new_blocks - 1] is the guy which will be
@@ -564,7 +640,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
         * 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(handle, inode, last_eb_bh,
+       status = ocfs2_journal_access(handle, inode, *last_eb_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (status < 0) {
                mlog_errno(status);
@@ -597,10 +673,10 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
         * next_leaf on the previously last-extent-block. */
        fe->i_last_eb_blk = cpu_to_le64(new_last_eb_blk);
 
-       eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
+       eb = (struct ocfs2_extent_block *) (*last_eb_bh)->b_data;
        eb->h_next_leaf_blk = cpu_to_le64(new_last_eb_blk);
 
-       status = ocfs2_journal_dirty(handle, last_eb_bh);
+       status = ocfs2_journal_dirty(handle, *last_eb_bh);
        if (status < 0)
                mlog_errno(status);
        status = ocfs2_journal_dirty(handle, fe_bh);
@@ -612,6 +688,14 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
                        mlog_errno(status);
        }
 
+       /*
+        * 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) {
@@ -831,10 +915,12 @@ bail:
  * 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(struct inode *inode, handle_t *handle,
                           struct buffer_head *di_bh, int *final_depth,
-                          struct buffer_head *last_eb_bh,
+                          struct buffer_head **last_eb_bh,
                           struct ocfs2_alloc_context *meta_ac)
 {
        int ret, shift;
@@ -869,10 +955,21 @@ static int ocfs2_grow_tree(struct inode *inode, handle_t *handle,
                        goto out;
                }
                depth++;
-               /* Special case: we have room now if we shifted from
-                * tree_depth 0 */
-               if (depth == 1)
+               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
@@ -998,6 +1095,22 @@ static void ocfs2_rotate_leaf(struct ocfs2_extent_list *el,
 
 }
 
+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 .
  *
@@ -1275,6 +1388,10 @@ static void ocfs2_adjust_adjacent_records(struct ocfs2_extent_rec *left_rec,
         * immediately to their right.
         */
        left_clusters = le32_to_cpu(right_child_el->l_recs[0].e_cpos);
+       if (ocfs2_is_empty_extent(&right_child_el->l_recs[0])) {
+               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);
 
@@ -1595,10 +1712,16 @@ 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 credits = (path->p_tree_depth - subtree_depth) * 2 + 1;
+       int credits = (path->p_tree_depth - subtree_depth) * 2 + 1 + op_credits;
 
        if (handle->h_buffer_credits < credits)
                return ocfs2_extend_trans(handle, credits);
@@ -1632,6 +1755,29 @@ static int ocfs2_rotate_requires_path_adjustment(struct ocfs2_path *left_path,
        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.
  *
@@ -1650,11 +1796,12 @@ static int ocfs2_rotate_requires_path_adjustment(struct ocfs2_path *left_path,
  */
 static int ocfs2_rotate_tree_right(struct inode *inode,
                                   handle_t *handle,
+                                  enum ocfs2_split_type split,
                                   u32 insert_cpos,
                                   struct ocfs2_path *right_path,
                                   struct ocfs2_path **ret_left_path)
 {
-       int ret, start;
+       int ret, start, orig_credits = handle->h_buffer_credits;
        u32 cpos;
        struct ocfs2_path *left_path = NULL;
 
@@ -1721,9 +1868,9 @@ static int ocfs2_rotate_tree_right(struct inode *inode,
                                (unsigned long long)
                                path_leaf_bh(left_path)->b_blocknr);
 
-               if (ocfs2_rotate_requires_path_adjustment(left_path,
+               if (split == SPLIT_NONE &&
+                   ocfs2_rotate_requires_path_adjustment(left_path,
                                                          insert_cpos)) {
-                       mlog(0, "Path adjustment required\n");
 
                        /*
                         * We've rotated the tree as much as we
@@ -1751,7 +1898,7 @@ static int ocfs2_rotate_tree_right(struct inode *inode,
                     right_path->p_tree_depth);
 
                ret = ocfs2_extend_rotate_transaction(handle, start,
-                                                     right_path);
+                                                     orig_credits, right_path);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
@@ -1764,6 +1911,24 @@ static int ocfs2_rotate_tree_right(struct inode *inode,
                        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
@@ -1786,677 +1951,2526 @@ out_ret_path:
        return ret;
 }
 
-/*
- * 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_rec *insert_rec,
-                                struct ocfs2_extent_list *el,
-                                struct ocfs2_insert_type *insert,
-                                struct inode *inode)
+static void ocfs2_update_edge_lengths(struct inode *inode, handle_t *handle,
+                                     struct ocfs2_path *path)
 {
-       int i = insert->ins_contig_index;
-       unsigned int range;
+       int i, idx;
        struct ocfs2_extent_rec *rec;
+       struct ocfs2_extent_list *el;
+       struct ocfs2_extent_block *eb;
+       u32 range;
 
-       BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
+       /* Path should always be rightmost. */
+       eb = (struct ocfs2_extent_block *)path_leaf_bh(path)->b_data;
+       BUG_ON(eb->h_next_leaf_blk != 0ULL);
 
-       /*
-        * 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;
-       }
+       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);
 
-       /*
-        * 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;
-       }
+       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];
 
-       /*
-        * 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);
+               rec->e_int_clusters = cpu_to_le32(range);
+               le32_add_cpu(&rec->e_int_clusters, -le32_to_cpu(rec->e_cpos));
 
-               mlog_bug_on_msg(le16_to_cpu(el->l_next_free_rec) >=
-                               le16_to_cpu(el->l_count),
-                               "inode %lu, depth %u, count %u, next free %u, "
-                               "rec.cpos %u, rec.clusters %u, "
-                               "insert.cpos %u, insert.clusters %u\n",
-                               inode->i_ino,
-                               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;
+               ocfs2_journal_dirty(handle, path->p_node[i].bh);
        }
-
-       /*
-        * Ok, we have to rotate.
-        *
-        * At this point, it is safe to assume that inserting into an
-        * empty leaf and appending to a leaf have both been handled
-        * above.
-        *
-        * This leaf needs to have space, either by the empty 1st
-        * extent record, or by virtue of an l_next_rec < l_count.
-        */
-       ocfs2_rotate_leaf(el, insert_rec);
 }
 
-static inline void ocfs2_update_dinode_clusters(struct inode *inode,
-                                               struct ocfs2_dinode *di,
-                                               u32 clusters)
+static void ocfs2_unlink_path(struct inode *inode, handle_t *handle,
+                             struct ocfs2_cached_dealloc_ctxt *dealloc,
+                             struct ocfs2_path *path, int unlink_start)
 {
-       le32_add_cpu(&di->i_clusters, clusters);
-       spin_lock(&OCFS2_I(inode)->ip_lock);
-       OCFS2_I(inode)->ip_clusters = le32_to_cpu(di->i_clusters);
-       spin_unlock(&OCFS2_I(inode)->ip_lock);
+       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_I(inode)->ip_blkno,
+                            (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(inode, 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(inode, bh);
+       }
 }
 
-static int ocfs2_append_rec_to_path(struct inode *inode, handle_t *handle,
-                                   struct ocfs2_extent_rec *insert_rec,
-                                   struct ocfs2_path *right_path,
-                                   struct ocfs2_path **ret_left_path)
+static void ocfs2_unlink_subtree(struct inode *inode, handle_t *handle,
+                                struct ocfs2_path *left_path,
+                                struct ocfs2_path *right_path,
+                                int subtree_index,
+                                struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
-       int ret, i, next_free;
-       struct buffer_head *bh;
+       int i;
+       struct buffer_head *root_bh = left_path->p_node[subtree_index].bh;
+       struct ocfs2_extent_list *root_el = left_path->p_node[subtree_index].el;
        struct ocfs2_extent_list *el;
-       struct ocfs2_path *left_path = NULL;
+       struct ocfs2_extent_block *eb;
 
-       *ret_left_path = NULL;
+       el = path_leaf_el(left_path);
 
-       /*
-        * 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);
+       eb = (struct ocfs2_extent_block *)right_path->p_node[subtree_index + 1].bh->b_data;
 
-       /*
-        * 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;
+       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;
 
-               ret = ocfs2_find_cpos_for_left_leaf(inode->i_sb, right_path,
-                                                   &left_cpos);
-               if (ret) {
-                       mlog_errno(ret);
-                       goto out;
-               }
+       BUG_ON(i >= le16_to_cpu(root_el->l_next_free_rec));
 
-               mlog(0, "Append may need a left path update. cpos: %u, "
-                    "left_cpos: %u\n", le32_to_cpu(insert_rec->e_cpos),
-                    left_cpos);
+       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(inode, handle, dealloc, right_path,
+                         subtree_index + 1);
+}
+
+static int ocfs2_rotate_subtree_left(struct inode *inode, handle_t *handle,
+                                    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, *di_bh = path_root_bh(right_path);
+       struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+       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])) {
                /*
-                * No need to worry if the append is already in the
-                * leftmost leaf.
+                * 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 (left_cpos) {
-                       left_path = ocfs2_new_path(path_root_bh(right_path),
-                                                  path_root_el(right_path));
-                       if (!left_path) {
-                               ret = -ENOMEM;
-                               mlog_errno(ret);
-                               goto out;
-                       }
 
-                       ret = ocfs2_find_path(inode, left_path, left_cpos);
+               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(handle, inode,
+                                                  path_leaf_bh(right_path),
+                                                  OCFS2_JOURNAL_ACCESS_WRITE);
                        if (ret) {
                                mlog_errno(ret);
                                goto out;
                        }
 
-                       /*
-                        * ocfs2_insert_path() will pass the left_path to the
-                        * journal for us.
-                        */
-               }
+                       ocfs2_remove_empty_extent(right_leaf_el);
+               } else
+                       right_has_empty = 1;
        }
 
-       ret = ocfs2_journal_access_path(inode, handle, right_path);
-       if (ret) {
-               mlog_errno(ret);
-               goto out;
-       }
+       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_journal_access(handle, inode, di_bh,
+                                          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_journal_access(handle, inode, root_bh,
+                                  OCFS2_JOURNAL_ACCESS_WRITE);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       for(i = subtree_index + 1; i < path_num_items(right_path); i++) {
+               ret = ocfs2_journal_access(handle, inode,
+                                          right_path->p_node[i].bh,
+                                          OCFS2_JOURNAL_ACCESS_WRITE);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               ret = ocfs2_journal_access(handle, inode,
+                                          left_path->p_node[i].bh,
+                                          OCFS2_JOURNAL_ACCESS_WRITE);
+               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);
+       }
+
+       ret = ocfs2_journal_dirty(handle, path_leaf_bh(left_path));
+       if (ret)
+               mlog_errno(ret);
+       ret = ocfs2_journal_dirty(handle, path_leaf_bh(right_path));
+       if (ret)
+               mlog_errno(ret);
+
+       if (del_right_subtree) {
+               ocfs2_unlink_subtree(inode, handle, left_path, right_path,
+                                    subtree_index, dealloc);
+               ocfs2_update_edge_lengths(inode, handle, left_path);
+
+               eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
+               di->i_last_eb_blk = 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);
+
+               ret = ocfs2_journal_dirty(handle, di_bh);
+               if (ret)
+                       mlog_errno(ret);
+
+               *deleted = 1;
+       } else
+               ocfs2_complete_edge_insert(inode, 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().
+ */
+static 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(struct inode *inode,
+                                           handle_t *handle,
+                                           struct buffer_head *bh,
+                                           struct ocfs2_extent_list *el)
+{
+       int ret;
+
+       if (!ocfs2_is_empty_extent(&el->l_recs[0]))
+               return 0;
+
+       ret = ocfs2_journal_access(handle, inode, bh,
+                                  OCFS2_JOURNAL_ACCESS_WRITE);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       ocfs2_remove_empty_extent(el);
+
+       ret = ocfs2_journal_dirty(handle, bh);
+       if (ret)
+               mlog_errno(ret);
+
+out:
+       return ret;
+}
+
+static int __ocfs2_rotate_tree_left(struct inode *inode,
+                                   handle_t *handle, 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;
+
+       BUG_ON(!ocfs2_is_empty_extent(&(path_leaf_el(path)->l_recs[0])));
+
+       *empty_extent_path = NULL;
+
+       ret = ocfs2_find_cpos_for_right_leaf(inode->i_sb, path,
+                                            &right_cpos);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       left_path = ocfs2_new_path(path_root_bh(path),
+                                  path_root_el(path));
+       if (!left_path) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto out;
+       }
+
+       ocfs2_cp_path(left_path, path);
+
+       right_path = ocfs2_new_path(path_root_bh(path),
+                                   path_root_el(path));
+       if (!right_path) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto out;
+       }
+
+       while (right_cpos) {
+               ret = ocfs2_find_path(inode, right_path, right_cpos);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               subtree_root = ocfs2_find_subtree_root(inode, left_path,
+                                                      right_path);
+
+               mlog(0, "Subtree root at index %d (blk %llu, depth %d)\n",
+                    subtree_root,
+                    (unsigned long long)
+                    right_path->p_node[subtree_root].bh->b_blocknr,
+                    right_path->p_tree_depth);
+
+               ret = ocfs2_extend_rotate_transaction(handle, subtree_root,
+                                                     orig_credits, left_path);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               ret = ocfs2_rotate_subtree_left(inode, handle, 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(inode->i_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(struct inode *inode, handle_t *handle,
+                                      struct ocfs2_path *path,
+                                      struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+       int ret, subtree_index;
+       u32 cpos;
+       struct ocfs2_path *left_path = NULL;
+       struct ocfs2_dinode *di;
+       struct ocfs2_extent_block *eb;
+       struct ocfs2_extent_list *el;
+
+       /*
+        * XXX: This code assumes that the root is an inode, which is
+        * true for now but may change as tree code gets generic.
+        */
+       di = (struct ocfs2_dinode *)path_root_bh(path)->b_data;
+       if (!OCFS2_IS_VALID_DINODE(di)) {
+               ret = -EIO;
+               ocfs2_error(inode->i_sb,
+                           "Inode %llu has invalid path root",
+                           (unsigned long long)OCFS2_I(inode)->ip_blkno);
+               goto out;
+       }
+
+       /*
+        * There's two ways we handle this depending on
+        * whether path is the only existing one.
+        */
+       ret = ocfs2_extend_rotate_transaction(handle, 0,
+                                             handle->h_buffer_credits,
+                                             path);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       ret = ocfs2_journal_access_path(inode, handle, path);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       ret = ocfs2_find_cpos_for_left_leaf(inode->i_sb, 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(path_root_bh(path),
+                                          path_root_el(path));
+               if (!left_path) {
+                       ret = -ENOMEM;
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               ret = ocfs2_find_path(inode, left_path, cpos);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               ret = ocfs2_journal_access_path(inode, handle, left_path);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               subtree_index = ocfs2_find_subtree_root(inode, left_path, path);
+
+               ocfs2_unlink_subtree(inode, handle, left_path, path,
+                                    subtree_index, dealloc);
+               ocfs2_update_edge_lengths(inode, handle, left_path);
+
+               eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
+               di->i_last_eb_blk = 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 inode back to having extents
+                * in-line.
+                */
+               ocfs2_unlink_path(inode, handle, dealloc, path, 1);
+
+               el = &di->id2.i_list;
+               el->l_tree_depth = 0;
+               el->l_next_free_rec = 0;
+               memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
+
+               di->i_last_eb_blk = 0;
+       }
+
+       ocfs2_journal_dirty(handle, path_root_bh(path));
+
+out:
+       ocfs2_free_path(left_path);
+       return ret;
+}
+
+/*
+ * Left rotation of btree records.
+ *
+ * In many ways, this is (unsurprisingly) the opposite of right
+ * rotation. We start at some non-rightmost path containing an empty
+ * extent in the leaf block. The code works its way to the rightmost
+ * path by rotating records to the left in every subtree.
+ *
+ * This is used by any code which reduces the number of extent records
+ * in a leaf. After removal, an empty record should be placed in the
+ * leftmost list position.
+ *
+ * This won't handle a length update of the rightmost path records if
+ * the rightmost tree leaf record is removed so the caller is
+ * responsible for detecting and correcting that.
+ */
+static int ocfs2_rotate_tree_left(struct inode *inode, handle_t *handle,
+                                 struct ocfs2_path *path,
+                                 struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+       int ret, orig_credits = handle->h_buffer_credits;
+       struct ocfs2_path *tmp_path = NULL, *restart_path = NULL;
+       struct ocfs2_extent_block *eb;
+       struct ocfs2_extent_list *el;
+
+       el = path_leaf_el(path);
+       if (!ocfs2_is_empty_extent(&el->l_recs[0]))
+               return 0;
+
+       if (path->p_tree_depth == 0) {
+rightmost_no_delete:
+               /*
+                * In-inode extents. This is trivially handled, so do
+                * it up front.
+                */
+               ret = ocfs2_rotate_rightmost_leaf_left(inode, handle,
+                                                      path_leaf_bh(path),
+                                                      path_leaf_el(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 inode back to inline extents.
+        */
+
+       eb = (struct ocfs2_extent_block *)path_leaf_bh(path)->b_data;
+       el = &eb->h_list;
+       if (eb->h_next_leaf_blk == 0) {
+               /*
+                * This gets a bit tricky if we're going to delete the
+                * rightmost path. Get the other cases out of the way
+                * 1st.
+                */
+               if (le16_to_cpu(el->l_next_free_rec) > 1)
+                       goto rightmost_no_delete;
+
+               if (le16_to_cpu(el->l_next_free_rec) == 0) {
+                       ret = -EIO;
+                       ocfs2_error(inode->i_sb,
+                                   "Inode %llu has empty extent block at %llu",
+                                   (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                                   (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(inode, handle, 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(inode, handle, 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(inode, handle, 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));
+       }
+}
+
+/*
+ * Remove split_rec clusters from the record at index and merge them
+ * onto the beginning of the record at index + 1.
+ */
+static int ocfs2_merge_rec_right(struct inode *inode, struct buffer_head *bh,
+                               handle_t *handle,
+                               struct ocfs2_extent_rec *split_rec,
+                               struct ocfs2_extent_list *el, int index)
+{
+       int ret;
+       unsigned int split_clusters = le16_to_cpu(split_rec->e_leaf_clusters);
+       struct ocfs2_extent_rec *left_rec;
+       struct ocfs2_extent_rec *right_rec;
+
+       BUG_ON(index >= le16_to_cpu(el->l_next_free_rec));
+
+       left_rec = &el->l_recs[index];
+       right_rec = &el->l_recs[index + 1];
+
+       ret = ocfs2_journal_access(handle, inode, bh,
+                                  OCFS2_JOURNAL_ACCESS_WRITE);
+       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(inode->i_sb, split_clusters));
+       le16_add_cpu(&right_rec->e_leaf_clusters, split_clusters);
+
+       ocfs2_cleanup_merge(el, index);
+
+       ret = ocfs2_journal_dirty(handle, bh);
+       if (ret)
+               mlog_errno(ret);
+
+out:
+       return ret;
+}
+
+/*
+ * Remove split_rec clusters from the record at index and merge them
+ * onto the tail of the record at index - 1.
+ */
+static int ocfs2_merge_rec_left(struct inode *inode, struct buffer_head *bh,
+                               handle_t *handle,
+                               struct ocfs2_extent_rec *split_rec,
+                               struct ocfs2_extent_list *el, int index)
+{
+       int ret, 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;
+
+       BUG_ON(index <= 0);
+
+       left_rec = &el->l_recs[index - 1];
+       right_rec = &el->l_recs[index];
+       if (ocfs2_is_empty_extent(&el->l_recs[0]))
+               has_empty_extent = 1;
+
+       ret = ocfs2_journal_access(handle, inode, bh,
+                                  OCFS2_JOURNAL_ACCESS_WRITE);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       if (has_empty_extent && index == 1) {
+               /*
+                * The easy case - we can just plop the record right in.
+                */
+               *left_rec = *split_rec;
+
+               has_empty_extent = 0;
+       } else {
+               le16_add_cpu(&left_rec->e_leaf_clusters, split_clusters);
+       }
+
+       le32_add_cpu(&right_rec->e_cpos, split_clusters);
+       le64_add_cpu(&right_rec->e_blkno,
+                    ocfs2_clusters_to_blocks(inode->i_sb, split_clusters));
+       le16_add_cpu(&right_rec->e_leaf_clusters, -split_clusters);
+
+       ocfs2_cleanup_merge(el, index);
+
+       ret = ocfs2_journal_dirty(handle, bh);
+       if (ret)
+               mlog_errno(ret);
+
+out:
+       return ret;
+}
+
+static int ocfs2_try_to_merge_extent(struct inode *inode,
+                                    handle_t *handle,
+                                    struct ocfs2_path *left_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(left_path);
+       struct ocfs2_extent_rec *rec = &el->l_recs[split_index];
+
+       BUG_ON(ctxt->c_contig_type == CONTIG_NONE);
+
+       if (ctxt->c_split_covers_rec && ctxt->c_has_empty_extent) {
+               /*
+                * The merge code will need to create an empty
+                * extent to take the place of the newly
+                * emptied slot. Remove any pre-existing empty
+                * extents - having more than one in a leaf is
+                * illegal.
+                */
+               ret = ocfs2_rotate_tree_left(inode, handle, left_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);
+               BUG_ON(split_index == 0);
+
+               /*
+                * 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.
+                */
+               ret = ocfs2_merge_rec_left(inode, path_leaf_bh(left_path),
+                                          handle, split_rec, el, split_index);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               /*
+                * We can only get this from logic error above.
+                */
+               BUG_ON(!ocfs2_is_empty_extent(&el->l_recs[0]));
+
+               /*
+                * The left merge left us with an empty extent, remove
+                * it.
+                */
+               ret = ocfs2_rotate_tree_left(inode, handle, left_path, dealloc);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+               split_index--;
+               rec = &el->l_recs[split_index];
+
+               /*
+                * Note that we don't pass split_rec here on purpose -
+                * we've merged it into the left side.
+                */
+               ret = ocfs2_merge_rec_right(inode, path_leaf_bh(left_path),
+                                           handle, rec, el, split_index);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               BUG_ON(!ocfs2_is_empty_extent(&el->l_recs[0]));
+
+               ret = ocfs2_rotate_tree_left(inode, handle, left_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(inode,
+                                                  path_leaf_bh(left_path),
+                                                  handle, split_rec, el,
+                                                  split_index);
+                       if (ret) {
+                               mlog_errno(ret);
+                               goto out;
+                       }
+               } else {
+                       ret = ocfs2_merge_rec_right(inode,
+                                                   path_leaf_bh(left_path),
+                                                   handle, split_rec, el,
+                                                   split_index);
+                       if (ret) {
+                               mlog_errno(ret);
+                               goto out;
+                       }
+               }
+
+               if (ctxt->c_split_covers_rec) {
+                       /*
+                        * The merge may have left an empty extent in
+                        * our leaf. Try to rotate it away.
+                        */
+                       ret = ocfs2_rotate_tree_left(inode, handle, left_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_rec *insert_rec,
+                                struct ocfs2_extent_list *el,
+                                struct ocfs2_insert_type *insert,
+                                struct inode *inode)
+{
+       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(inode->i_sb, 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),
+                               "inode %lu, depth %u, count %u, next free %u, "
+                               "rec.cpos %u, rec.clusters %u, "
+                               "insert.cpos %u, insert.clusters %u\n",
+                               inode->i_ino,
+                               le16_to_cpu(el->l_tree_depth),
+                               le16_to_cpu(el->l_count),
+                               le16_to_cpu(el->l_next_free_rec),
+                               le32_to_cpu(el->l_recs[i].e_cpos),
+                               le16_to_cpu(el->l_recs[i].e_leaf_clusters),
+                               le32_to_cpu(insert_rec->e_cpos),
+                               le16_to_cpu(insert_rec->e_leaf_clusters));
+               i++;
+               el->l_recs[i] = *insert_rec;
+               le16_add_cpu(&el->l_next_free_rec, 1);
+               return;
+       }
+
+rotate:
+       /*
+        * Ok, we have to rotate.
+        *
+        * At this point, it is safe to assume that inserting into an
+        * empty leaf and appending to a leaf have both been handled
+        * above.
+        *
+        * This leaf needs to have space, either by the empty 1st
+        * extent record, or by virtue of an l_next_rec < l_count.
+        */
+       ocfs2_rotate_leaf(el, insert_rec);
+}
+
+static inline void ocfs2_update_dinode_clusters(struct inode *inode,
+                                               struct ocfs2_dinode *di,
+                                               u32 clusters)
+{
+       le32_add_cpu(&di->i_clusters, clusters);
+       spin_lock(&OCFS2_I(inode)->ip_lock);
+       OCFS2_I(inode)->ip_clusters = le32_to_cpu(di->i_clusters);
+       spin_unlock(&OCFS2_I(inode)->ip_lock);
+}
+
+static void ocfs2_adjust_rightmost_records(struct inode *inode,
+                                          handle_t *handle,
+                                          struct ocfs2_path *path,
+                                          struct ocfs2_extent_rec *insert_rec)
+{
+       int ret, i, next_free;
+       struct buffer_head *bh;
+       struct ocfs2_extent_list *el;
+       struct ocfs2_extent_rec *rec;
+
+       /*
+        * Update everything except the leaf block.
+        */
+       for (i = 0; i < path->p_tree_depth; i++) {
+               bh = path->p_node[i].bh;
+               el = path->p_node[i].el;
+
+               next_free = le16_to_cpu(el->l_next_free_rec);
+               if (next_free == 0) {
+                       ocfs2_error(inode->i_sb,
+                                   "Dinode %llu has a bad extent list",
+                                   (unsigned long long)OCFS2_I(inode)->ip_blkno);
+                       ret = -EIO;
+                       return;
+               }
+
+               rec = &el->l_recs[next_free - 1];
+
+               rec->e_int_clusters = insert_rec->e_cpos;
+               le32_add_cpu(&rec->e_int_clusters,
+                            le16_to_cpu(insert_rec->e_leaf_clusters));
+               le32_add_cpu(&rec->e_int_clusters,
+                            -le32_to_cpu(rec->e_cpos));
+
+               ret = ocfs2_journal_dirty(handle, bh);
+               if (ret)
+                       mlog_errno(ret);
+
+       }
+}
+
+static int ocfs2_append_rec_to_path(struct inode *inode, handle_t *handle,
+                                   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(inode->i_sb, right_path,
+                                                   &left_cpos);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               mlog(0, "Append may need a left path update. cpos: %u, "
+                    "left_cpos: %u\n", 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(path_root_bh(right_path),
+                                                  path_root_el(right_path));
+                       if (!left_path) {
+                               ret = -ENOMEM;
+                               mlog_errno(ret);
+                               goto out;
+                       }
+
+                       ret = ocfs2_find_path(inode, 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(inode, handle, right_path);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       ocfs2_adjust_rightmost_records(inode, handle, 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 inode *inode,
+                              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(inode->i_sb, split, rec, split_rec);
+       ocfs2_rotate_leaf(insert_el, split_rec);
+}
+
+/*
+ * This function only does inserts on an allocation b-tree. For dinode
+ * lists, 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(struct inode *inode,
+                            handle_t *handle,
+                            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);
+
+       /*
+        * Pass both paths to the journal. The majority of inserts
+        * will be touching all components anyway.
+        */
+       ret = ocfs2_journal_access_path(inode, handle, right_path);
+       if (ret < 0) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       if (left_path) {
+               int credits = handle->h_buffer_credits;
+
+               /*
+                * 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.
+                */
+               credits += left_path->p_tree_depth;
+
+               ret = ocfs2_extend_trans(handle, credits);
+               if (ret < 0) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               ret = ocfs2_journal_access_path(inode, handle, left_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 seperate
+                * function sort it all out.
+                */
+               ocfs2_split_record(inode, left_path, right_path,
+                                  insert_rec, insert->ins_split);
+       } else
+               ocfs2_insert_at_leaf(insert_rec, path_leaf_el(right_path),
+                                    insert, inode);
+
+       ret = ocfs2_journal_dirty(handle, leaf_bh);
+       if (ret)
+               mlog_errno(ret);
+
+       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(inode, left_path,
+                                                       right_path);
+               ocfs2_complete_edge_insert(inode, handle, left_path,
+                                          right_path, subtree_index);
+       }
+
+       ret = 0;
+out:
+       return ret;
+}
+
+static int ocfs2_do_insert_extent(struct inode *inode,
+                                 handle_t *handle,
+                                 struct buffer_head *di_bh,
+                                 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_dinode *di;
+       struct ocfs2_extent_list *el;
+
+       di = (struct ocfs2_dinode *) di_bh->b_data;
+       el = &di->id2.i_list;
+
+       ret = ocfs2_journal_access(handle, inode, di_bh,
+                                  OCFS2_JOURNAL_ACCESS_WRITE);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       if (le16_to_cpu(el->l_tree_depth) == 0) {
+               ocfs2_insert_at_leaf(insert_rec, el, type, inode);
+               goto out_update_clusters;
+       }
+
+       right_path = ocfs2_new_inode_path(di_bh);
+       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(inode, 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(inode, handle, type->ins_split,
+                                             le32_to_cpu(insert_rec->e_cpos),
+                                             right_path, &left_path);
+               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(inode, handle, insert_rec,
+                                              right_path, &left_path);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+       }
+
+       ret = ocfs2_insert_path(inode, handle, left_path, right_path,
+                               insert_rec, type);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+out_update_clusters:
+       if (type->ins_split == SPLIT_NONE)
+               ocfs2_update_dinode_clusters(inode, di,
+                                            le16_to_cpu(insert_rec->e_leaf_clusters));
+
+       ret = ocfs2_journal_dirty(handle, di_bh);
+       if (ret)
+               mlog_errno(ret);
+
+out:
+       ocfs2_free_path(left_path);
+       ocfs2_free_path(right_path);
+
+       return ret;
+}
+
+static enum ocfs2_contig_type
+ocfs2_figure_merge_contig_type(struct inode *inode,
+                              struct ocfs2_extent_list *el, int index,
+                              struct ocfs2_extent_rec *split_rec)
+{
+       struct ocfs2_extent_rec *rec;
+       enum ocfs2_contig_type ret = CONTIG_NONE;
+
+       /*
+        * We're careful to check for an empty extent record here -
+        * the merge code will know what to do if it sees one.
+        */
+
+       if (index > 0) {
+               rec = &el->l_recs[index - 1];
+               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_extent_contig(inode, rec, split_rec);
+               }
+       }
+
+       if (index < (le16_to_cpu(el->l_next_free_rec) - 1)) {
+               enum ocfs2_contig_type contig_type;
+
+               rec = &el->l_recs[index + 1];
+               contig_type = ocfs2_extent_contig(inode, rec, split_rec);
+
+               if (contig_type == CONTIG_LEFT && ret == CONTIG_RIGHT)
+                       ret = CONTIG_LEFTRIGHT;
+               else if (ret == CONTIG_NONE)
+                       ret = contig_type;
+       }
+
+       return ret;
+}
+
+static void ocfs2_figure_contig_type(struct inode *inode,
+                                    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_extent_contig(inode, &el->l_recs[i],
+                                                 insert_rec);
+               if (contig_type != CONTIG_NONE) {
+                       insert->ins_contig_index = i;
+                       break;
+               }
+       }
+       insert->ins_contig = contig_type;
+}
+
+/*
+ * 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 dinode list for tree's with 0
+ * depth. If we consider the dinode 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 begining 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 inode *inode,
+                                   struct buffer_head *di_bh,
+                                   struct buffer_head **last_eb_bh,
+                                   struct ocfs2_extent_rec *insert_rec,
+                                   int *free_records,
+                                   struct ocfs2_insert_type *insert)
+{
+       int ret;
+       struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+       struct ocfs2_extent_block *eb;
+       struct ocfs2_extent_list *el;
+       struct ocfs2_path *path = NULL;
+       struct buffer_head *bh = NULL;
 
-       el = path_root_el(right_path);
-       bh = path_root_bh(right_path);
-       i = 0;
-       while (1) {
-               struct ocfs2_extent_rec *rec;
+       insert->ins_split = SPLIT_NONE;
 
-               next_free = le16_to_cpu(el->l_next_free_rec);
-               if (next_free == 0) {
-                       ocfs2_error(inode->i_sb,
-                                   "Dinode %llu has a bad extent list",
-                                   (unsigned long long)OCFS2_I(inode)->ip_blkno);
-                       ret = -EIO;
+       el = &di->id2.i_list;
+       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_block(OCFS2_SB(inode->i_sb),
+                                      le64_to_cpu(di->i_last_eb_blk), &bh,
+                                      OCFS2_BH_CACHED, inode);
+               if (ret) {
+                       mlog_exit(ret);
                        goto out;
                }
+               eb = (struct ocfs2_extent_block *) bh->b_data;
+               el = &eb->h_list;
+       }
 
-               rec = &el->l_recs[next_free - 1];
+       /*
+        * 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);
 
-               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));
+       if (!insert->ins_tree_depth) {
+               ocfs2_figure_contig_type(inode, insert, el, insert_rec);
+               ocfs2_figure_appending_type(insert, el, insert_rec);
+               return 0;
+       }
 
-               ret = ocfs2_journal_dirty(handle, bh);
-               if (ret)
+       path = ocfs2_new_inode_path(di_bh);
+       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(inode, 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(inode, 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 (le64_to_cpu(di->i_last_eb_blk) == 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 an inode btree.
+ *
+ * The caller needs to update fe->i_clusters
+ */
+int ocfs2_insert_extent(struct ocfs2_super *osb,
+                       handle_t *handle,
+                       struct inode *inode,
+                       struct buffer_head *fe_bh,
+                       u32 cpos,
+                       u64 start_blk,
+                       u32 new_clusters,
+                       u8 flags,
+                       struct ocfs2_alloc_context *meta_ac)
+{
+       int status;
+       int uninitialized_var(free_records);
+       struct buffer_head *last_eb_bh = NULL;
+       struct ocfs2_insert_type insert = {0, };
+       struct ocfs2_extent_rec rec;
+
+       mlog(0, "add %u clusters at position %u to inode %llu\n",
+            new_clusters, cpos, (unsigned long long)OCFS2_I(inode)->ip_blkno);
+
+       mlog_bug_on_msg(!ocfs2_sparse_alloc(osb) &&
+                       (OCFS2_I(inode)->ip_clusters != cpos),
+                       "Device %s, asking for sparse allocation: inode %llu, "
+                       "cpos %u, clusters %u\n",
+                       osb->dev_str,
+                       (unsigned long long)OCFS2_I(inode)->ip_blkno, cpos,
+                       OCFS2_I(inode)->ip_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_figure_insert_type(inode, fe_bh, &last_eb_bh, &rec,
+                                         &free_records, &insert);
+       if (status < 0) {
+               mlog_errno(status);
+               goto bail;
+       }
+
+       mlog(0, "Insert.appending: %u, Insert.Contig: %u, "
+            "Insert.contig_index: %d, Insert.free_records: %d, "
+            "Insert.tree_depth: %d\n",
+            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(inode, handle, fe_bh,
+                                        &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(inode, handle, fe_bh, &rec, &insert);
+       if (status < 0)
+               mlog_errno(status);
+       else
+               ocfs2_extent_map_insert_rec(inode, &rec);
+
+bail:
+       if (last_eb_bh)
+               brelse(last_eb_bh);
+
+       mlog_exit(status);
+       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(struct inode *inode,
+                                 handle_t *handle,
+                                 struct ocfs2_path *path,
+                                 struct buffer_head *di_bh,
+                                 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;
+       struct ocfs2_dinode *di;
+
+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];
+
+       di = (struct ocfs2_dinode *)di_bh->b_data;
+       rightmost_el = &di->id2.i_list;
+
+       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(inode, handle, di_bh, &depth, last_eb_bh,
+                                     meta_ac);
+               if (ret) {
                        mlog_errno(ret);
+                       goto out;
+               }
+       }
 
-               /* Don't touch the leaf node */
-               if (++i >= right_path->p_tree_depth)
-                       break;
+       memset(&insert, 0, sizeof(struct ocfs2_insert_type));
+       insert.ins_appending = APPEND_NONE;
+       insert.ins_contig = CONTIG_NONE;
+       insert.ins_tree_depth = depth;
 
-               bh = right_path->p_node[i].bh;
-               el = right_path->p_node[i].el;
+       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(inode->i_sb, &tmprec, insert_range,
+                                          &rec);
+
+               split_rec = tmprec;
+
+               BUG_ON(do_leftright);
+               do_leftright = 1;
        }
 
-       *ret_left_path = left_path;
-       ret = 0;
+       ret = ocfs2_do_insert_extent(inode, handle, di_bh, &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(inode, path, cpos);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               el = path_leaf_el(path);
+               split_index = ocfs2_search_extent_list(el, cpos);
+               goto leftright;
+       }
 out:
-       if (ret != 0)
-               ocfs2_free_path(left_path);
 
        return ret;
 }
 
 /*
- * This function only does inserts on an allocation b-tree. For dinode
- * lists, ocfs2_insert_at_leaf() is called directly.
+ * Mark part or all of the extent record at split_index in the leaf
+ * pointed to by path as written. This removes the unwritten
+ * extent flag.
  *
- * 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.
+ * 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 inode with a
+ * 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.
  */
-static int ocfs2_insert_path(struct inode *inode,
-                            handle_t *handle,
-                            struct ocfs2_path *left_path,
-                            struct ocfs2_path *right_path,
-                            struct ocfs2_extent_rec *insert_rec,
-                            struct ocfs2_insert_type *insert)
+static int __ocfs2_mark_extent_written(struct inode *inode,
+                                      struct buffer_head *di_bh,
+                                      handle_t *handle,
+                                      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, subtree_index;
-       struct buffer_head *leaf_bh = path_leaf_bh(right_path);
-       struct ocfs2_extent_list *el;
+       int ret = 0;
+       struct ocfs2_extent_list *el = path_leaf_el(path);
+       struct buffer_head *eb_bh, *last_eb_bh = NULL;
+       struct ocfs2_extent_rec *rec = &el->l_recs[split_index];
+       struct ocfs2_merge_ctxt ctxt;
+       struct ocfs2_extent_list *rightmost_el;
+
+       if (!rec->e_flags & OCFS2_EXT_UNWRITTEN) {
+               ret = -EIO;
+               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(inode, handle, right_path);
-       if (ret < 0) {
+       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;
        }
 
-       if (left_path) {
-               int credits = handle->h_buffer_credits;
+       eb_bh = path_leaf_bh(path);
+       ret = ocfs2_journal_access(handle, inode, eb_bh,
+                                  OCFS2_JOURNAL_ACCESS_WRITE);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
 
-               /*
-                * 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.
-                */
-               credits += left_path->p_tree_depth;
+       ctxt.c_contig_type = ocfs2_figure_merge_contig_type(inode, el,
+                                                           split_index,
+                                                           split_rec);
 
-               ret = ocfs2_extend_trans(handle, credits);
-               if (ret < 0) {
-                       mlog_errno(ret);
+       /*
+        * The core merge / split code wants to know how much room is
+        * left in this inodes allocation tree, so we pass the
+        * rightmost extent list.
+        */
+       if (path->p_tree_depth) {
+               struct ocfs2_extent_block *eb;
+               struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+
+               ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
+                                      le64_to_cpu(di->i_last_eb_blk),
+                                      &last_eb_bh, OCFS2_BH_CACHED, inode);
+               if (ret) {
+                       mlog_exit(ret);
                        goto out;
                }
 
-               ret = ocfs2_journal_access_path(inode, handle, left_path);
-               if (ret < 0) {
-                       mlog_errno(ret);
+               eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
+               if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
+                       OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
+                       ret = -EROFS;
                        goto out;
                }
-       }
 
-       el = path_leaf_el(right_path);
+               rightmost_el = &eb->h_list;
+       } else
+               rightmost_el = path_root_el(path);
 
-       ocfs2_insert_at_leaf(insert_rec, el, insert, inode);
-       ret = ocfs2_journal_dirty(handle, leaf_bh);
-       if (ret)
-               mlog_errno(ret);
+       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;
 
-       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(inode, left_path,
-                                                       right_path);
-               ocfs2_complete_edge_insert(inode, handle, left_path,
-                                          right_path, subtree_index);
+       ctxt.c_has_empty_extent = ocfs2_is_empty_extent(&el->l_recs[0]);
+
+       mlog(0, "index: %d, contig: %u, has_empty: %u, split_covers: %u\n",
+            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)
+                       el->l_recs[split_index] = *split_rec;
+               else
+                       ret = ocfs2_split_and_insert(inode, handle, path, di_bh,
+                                                    &last_eb_bh, split_index,
+                                                    split_rec, meta_ac);
+               if (ret)
+                       mlog_errno(ret);
+       } else {
+               ret = ocfs2_try_to_merge_extent(inode, handle, path,
+                                               split_index, split_rec,
+                                               dealloc, &ctxt);
+               if (ret)
+                       mlog_errno(ret);
        }
 
-       ret = 0;
+       ocfs2_journal_dirty(handle, eb_bh);
+
 out:
+       brelse(last_eb_bh);
        return ret;
 }
 
-static int ocfs2_do_insert_extent(struct inode *inode,
-                                 handle_t *handle,
-                                 struct buffer_head *di_bh,
-                                 struct ocfs2_extent_rec *insert_rec,
-                                 struct ocfs2_insert_type *type)
+/*
+ * Mark the already-existing extent at cpos as written for len clusters.
+ *
+ * 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 buffer_head *di_bh,
+                             handle_t *handle, u32 cpos, u32 len, u32 phys,
+                             struct ocfs2_alloc_context *meta_ac,
+                             struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
-       int ret, rotate = 0;
-       u32 cpos;
-       struct ocfs2_path *right_path = NULL;
+       int ret, index;
+       u64 start_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys);
+       struct ocfs2_extent_rec split_rec;
        struct ocfs2_path *left_path = NULL;
-       struct ocfs2_dinode *di;
        struct ocfs2_extent_list *el;
 
-       di = (struct ocfs2_dinode *) di_bh->b_data;
-       el = &di->id2.i_list;
+       mlog(0, "Inode %lu cpos %u, len %u, phys %u (%llu)\n",
+            inode->i_ino, cpos, len, phys, (unsigned long long)start_blkno);
 
-       ret = ocfs2_journal_access(handle, inode, di_bh,
-                                  OCFS2_JOURNAL_ACCESS_WRITE);
-       if (ret) {
-               mlog_errno(ret);
+       if (!ocfs2_writes_unwritten_extents(OCFS2_SB(inode->i_sb))) {
+               ocfs2_error(inode->i_sb, "Inode %llu has unwritten extents "
+                           "that are being written to, but the feature bit "
+                           "is not set in the super block.",
+                           (unsigned long long)OCFS2_I(inode)->ip_blkno);
+               ret = -EROFS;
                goto out;
        }
 
-       if (le16_to_cpu(el->l_tree_depth) == 0) {
-               ocfs2_insert_at_leaf(insert_rec, el, type, inode);
-               goto out_update_clusters;
-       }
+       /*
+        * XXX: This should be fixed up so that we just re-insert the
+        * next extent records.
+        */
+       ocfs2_extent_map_trunc(inode, 0);
 
-       right_path = ocfs2_new_inode_path(di_bh);
-       if (!right_path) {
+       left_path = ocfs2_new_inode_path(di_bh);
+       if (!left_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(inode, right_path, cpos);
+       ret = ocfs2_find_path(inode, left_path, cpos);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
+       el = path_leaf_el(left_path);
 
-       /*
-        * 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(inode, handle,
-                                             le32_to_cpu(insert_rec->e_cpos),
-                                             right_path, &left_path);
-               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(inode, handle, insert_rec,
-                                              right_path, &left_path);
-               if (ret) {
-                       mlog_errno(ret);
-                       goto out;
-               }
-       }
-
-       ret = ocfs2_insert_path(inode, handle, left_path, right_path,
-                               insert_rec, type);
-       if (ret) {
-               mlog_errno(ret);
+       index = ocfs2_search_extent_list(el, cpos);
+       if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+               ocfs2_error(inode->i_sb,
+                           "Inode %llu has an extent at cpos %u which can no "
+                           "longer be found.\n",
+                           (unsigned long long)OCFS2_I(inode)->ip_blkno, cpos);
+               ret = -EROFS;
                goto out;
        }
 
-out_update_clusters:
-       ocfs2_update_dinode_clusters(inode, di,
-                                    le16_to_cpu(insert_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(len);
+       split_rec.e_blkno = cpu_to_le64(start_blkno);
+       split_rec.e_flags = path_leaf_el(left_path)->l_recs[index].e_flags;
+       split_rec.e_flags &= ~OCFS2_EXT_UNWRITTEN;
 
-       ret = ocfs2_journal_dirty(handle, di_bh);
+       ret = __ocfs2_mark_extent_written(inode, di_bh, handle, left_path,
+                                         index, &split_rec, meta_ac, dealloc);
        if (ret)
                mlog_errno(ret);
 
 out:
        ocfs2_free_path(left_path);
-       ocfs2_free_path(right_path);
-
        return ret;
 }
 
-static void ocfs2_figure_contig_type(struct inode *inode,
-                                    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_extent_contig(inode, &el->l_recs[i],
-                                                 insert_rec);
-               if (contig_type != CONTIG_NONE) {
-                       insert->ins_contig_index = i;
-                       break;
-               }
-       }
-       insert->ins_contig = contig_type;
-}
-
-/*
- * 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 dinode list for tree's with 0
- * depth. If we consider the dinode 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)
+static int ocfs2_split_tree(struct inode *inode, struct buffer_head *di_bh,
+                           handle_t *handle, struct ocfs2_path *path,
+                           int index, u32 new_range,
+                           struct ocfs2_alloc_context *meta_ac)
 {
-       int i;
-       u32 cpos = le32_to_cpu(insert_rec->e_cpos);
+       int ret, depth, credits = handle->h_buffer_credits;
+       struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+       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;
 
-       insert->ins_appending = APPEND_NONE;
+       /*
+        * 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(inode->i_sb, &split_rec, new_range, rec);
 
-       BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
+       depth = path->p_tree_depth;
+       if (depth > 0) {
+               ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
+                                      le64_to_cpu(di->i_last_eb_blk),
+                                      &last_eb_bh, OCFS2_BH_CACHED, inode);
+               if (ret < 0) {
+                       mlog_errno(ret);
+                       goto out;
+               }
 
-       if (!el->l_next_free_rec)
-               goto set_tail_append;
+               eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
+               rightmost_el = &eb->h_list;
+       } else
+               rightmost_el = path_leaf_el(path);
 
-       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;
+       credits += path->p_tree_depth + ocfs2_extend_meta_needed(di);
+       ret = ocfs2_extend_trans(handle, credits);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
        }
 
-       i = le16_to_cpu(el->l_next_free_rec) - 1;
-       rec = &el->l_recs[i];
+       if (le16_to_cpu(rightmost_el->l_next_free_rec) ==
+           le16_to_cpu(rightmost_el->l_count)) {
+               ret = ocfs2_grow_tree(inode, handle, di_bh, &depth, &last_eb_bh,
+                                     meta_ac);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+       }
 
-       if (cpos >=
-           (le32_to_cpu(rec->e_cpos) + le16_to_cpu(rec->e_leaf_clusters)))
-               goto set_tail_append;
+       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;
 
-       return;
+       ret = ocfs2_do_insert_extent(inode, handle, di_bh, &split_rec, &insert);
+       if (ret)
+               mlog_errno(ret);
 
-set_tail_append:
-       insert->ins_appending = APPEND_TAIL;
+out:
+       brelse(last_eb_bh);
+       return ret;
 }
 
-/*
- * Helper function called at the begining 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 inode *inode,
-                                   struct buffer_head *di_bh,
-                                   struct buffer_head **last_eb_bh,
-                                   struct ocfs2_extent_rec *insert_rec,
-                                   struct ocfs2_insert_type *insert)
+static int ocfs2_truncate_rec(struct inode *inode, handle_t *handle,
+                             struct ocfs2_path *path, int index,
+                             struct ocfs2_cached_dealloc_ctxt *dealloc,
+                             u32 cpos, u32 len)
 {
        int ret;
-       struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+       u32 left_cpos, rec_range, trunc_range;
+       int wants_rotate = 0, is_rightmost_tree_rec = 0;
+       struct super_block *sb = inode->i_sb;
+       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;
-       struct ocfs2_extent_list *el;
-       struct ocfs2_path *path = NULL;
-       struct buffer_head *bh = NULL;
 
-       el = &di->id2.i_list;
-       insert->ins_tree_depth = le16_to_cpu(el->l_tree_depth);
+       if (ocfs2_is_empty_extent(&el->l_recs[0]) && index > 0) {
+               ret = ocfs2_rotate_tree_left(inode, handle, path, dealloc);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               index--;
+       }
 
-       if (el->l_tree_depth) {
+       if (index == (le16_to_cpu(el->l_next_free_rec) - 1) &&
+           path->p_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.
+                * 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.
                 */
-               ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
-                                      le64_to_cpu(di->i_last_eb_blk), &bh,
-                                      OCFS2_BH_CACHED, inode);
+               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 inode tree.
+                *   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(inode->i_sb, path,
+                                                   &left_cpos);
                if (ret) {
-                       mlog_exit(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.
-        */
-       insert->ins_free_records = le16_to_cpu(el->l_count) -
-               le16_to_cpu(el->l_next_free_rec);
+               if (left_cpos && le16_to_cpu(el->l_next_free_rec) > 1) {
+                       left_path = ocfs2_new_path(path_root_bh(path),
+                                                  path_root_el(path));
+                       if (!left_path) {
+                               ret = -ENOMEM;
+                               mlog_errno(ret);
+                               goto out;
+                       }
 
-       if (!insert->ins_tree_depth) {
-               ocfs2_figure_contig_type(inode, insert, el, insert_rec);
-               ocfs2_figure_appending_type(insert, el, insert_rec);
-               return 0;
+                       ret = ocfs2_find_path(inode, left_path, left_cpos);
+                       if (ret) {
+                               mlog_errno(ret);
+                               goto out;
+                       }
+               }
        }
 
-       path = ocfs2_new_inode_path(di_bh);
-       if (!path) {
-               ret = -ENOMEM;
+       ret = ocfs2_extend_rotate_transaction(handle, 0,
+                                             handle->h_buffer_credits,
+                                             path);
+       if (ret) {
                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(inode, path, le32_to_cpu(insert_rec->e_cpos));
+       ret = ocfs2_journal_access_path(inode, handle, path);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
 
-       el = path_leaf_el(path);
+       ret = ocfs2_journal_access_path(inode, handle, left_path);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
 
-       /*
-        * 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(inode, insert, el, insert_rec);
+       rec_range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
+       trunc_range = cpos + len;
 
-       /*
-        * 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;
+       if (le32_to_cpu(rec->e_cpos) == cpos && rec_range == trunc_range) {
+               int next_free;
 
-       /*
-        * 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 (le64_to_cpu(di->i_last_eb_blk) == 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);
+               memset(rec, 0, sizeof(*rec));
+               ocfs2_cleanup_merge(el, index);
+               wants_rotate = 1;
+
+               next_free = le16_to_cpu(el->l_next_free_rec);
+               if (is_rightmost_tree_rec && next_free > 1) {
+                       /*
+                        * We skip the edge update if this path will
+                        * be deleted by the rotate code.
+                        */
+                       rec = &el->l_recs[next_free - 1];
+                       ocfs2_adjust_rightmost_records(inode, handle, 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(inode, handle, path, rec);
+       } else {
+               /* Caller should have trapped this. */
+               mlog(ML_ERROR, "Inode %llu: Invalid record truncate: (%u, %u) "
+                    "(%u, %u)\n", (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                    le32_to_cpu(rec->e_cpos),
+                    le16_to_cpu(rec->e_leaf_clusters), cpos, len);
+               BUG();
        }
 
-out:
-       ocfs2_free_path(path);
+       if (left_path) {
+               int subtree_index;
 
-       if (ret == 0)
-               *last_eb_bh = bh;
-       else
-               brelse(bh);
+               subtree_index = ocfs2_find_subtree_root(inode, left_path, path);
+               ocfs2_complete_edge_insert(inode, handle, left_path, path,
+                                          subtree_index);
+       }
+
+       ocfs2_journal_dirty(handle, path_leaf_bh(path));
+
+       ret = ocfs2_rotate_tree_left(inode, handle, path, dealloc);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+out:
+       ocfs2_free_path(left_path);
        return ret;
 }
 
-/*
- * Insert an extent into an inode btree.
- *
- * The caller needs to update fe->i_clusters
- */
-int ocfs2_insert_extent(struct ocfs2_super *osb,
-                       handle_t *handle,
-                       struct inode *inode,
-                       struct buffer_head *fe_bh,
-                       u32 cpos,
-                       u64 start_blk,
-                       u32 new_clusters,
-                       struct ocfs2_alloc_context *meta_ac)
+int ocfs2_remove_extent(struct inode *inode, struct buffer_head *di_bh,
+                       u32 cpos, u32 len, handle_t *handle,
+                       struct ocfs2_alloc_context *meta_ac,
+                       struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
-       int status;
-       struct buffer_head *last_eb_bh = NULL;
-       struct buffer_head *bh = NULL;
-       struct ocfs2_insert_type insert = {0, };
-       struct ocfs2_extent_rec rec;
+       int ret, index;
+       u32 rec_range, trunc_range;
+       struct ocfs2_extent_rec *rec;
+       struct ocfs2_extent_list *el;
+       struct ocfs2_path *path;
 
-       mlog(0, "add %u clusters at position %u to inode %llu\n",
-            new_clusters, cpos, (unsigned long long)OCFS2_I(inode)->ip_blkno);
+       ocfs2_extent_map_trunc(inode, 0);
 
-       mlog_bug_on_msg(!ocfs2_sparse_alloc(osb) &&
-                       (OCFS2_I(inode)->ip_clusters != cpos),
-                       "Device %s, asking for sparse allocation: inode %llu, "
-                       "cpos %u, clusters %u\n",
-                       osb->dev_str,
-                       (unsigned long long)OCFS2_I(inode)->ip_blkno, cpos,
-                       OCFS2_I(inode)->ip_clusters);
+       path = ocfs2_new_inode_path(di_bh);
+       if (!path) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto out;
+       }
 
-       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);
+       ret = ocfs2_find_path(inode, path, cpos);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
 
-       status = ocfs2_figure_insert_type(inode, fe_bh, &last_eb_bh, &rec,
-                                         &insert);
-       if (status < 0) {
-               mlog_errno(status);
-               goto bail;
+       el = path_leaf_el(path);
+       index = ocfs2_search_extent_list(el, cpos);
+       if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+               ocfs2_error(inode->i_sb,
+                           "Inode %llu has an extent at cpos %u which can no "
+                           "longer be found.\n",
+                           (unsigned long long)OCFS2_I(inode)->ip_blkno, cpos);
+               ret = -EROFS;
+               goto out;
        }
 
-       mlog(0, "Insert.appending: %u, Insert.Contig: %u, "
-            "Insert.contig_index: %d, Insert.free_records: %d, "
-            "Insert.tree_depth: %d\n",
-            insert.ins_appending, insert.ins_contig, insert.ins_contig_index,
-            insert.ins_free_records, insert.ins_tree_depth);
+       /*
+        * 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;
 
-       if (insert.ins_contig == CONTIG_NONE && insert.ins_free_records == 0) {
-               status = ocfs2_grow_tree(inode, handle, fe_bh,
-                                        &insert.ins_tree_depth, last_eb_bh,
-                                        meta_ac);
-               if (status) {
-                       mlog_errno(status);
-                       goto bail;
+       BUG_ON(cpos < le32_to_cpu(rec->e_cpos) || trunc_range > rec_range);
+
+       mlog(0, "Inode %llu, remove (cpos %u, len %u). Existing index %d "
+            "(cpos %u, len %u)\n",
+            (unsigned long long)OCFS2_I(inode)->ip_blkno, 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(inode, handle, path, index, dealloc,
+                                        cpos, len);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+       } else {
+               ret = ocfs2_split_tree(inode, di_bh, handle, path, index,
+                                      trunc_range, meta_ac);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
                }
-       }
 
-       /* Finally, we can add clusters. This might rotate the tree for us. */
-       status = ocfs2_do_insert_extent(inode, handle, fe_bh, &rec, &insert);
-       if (status < 0)
-               mlog_errno(status);
-       else
-               ocfs2_extent_map_insert_rec(inode, &rec);
+               /*
+                * 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);
 
-bail:
-       if (bh)
-               brelse(bh);
+               ret = ocfs2_find_path(inode, path, cpos);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
 
-       if (last_eb_bh)
-               brelse(last_eb_bh);
+               el = path_leaf_el(path);
+               index = ocfs2_search_extent_list(el, cpos);
+               if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+                       ocfs2_error(inode->i_sb,
+                                   "Inode %llu: split at cpos %u lost record.",
+                                   (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                                   cpos);
+                       ret = -EROFS;
+                       goto out;
+               }
 
-       mlog_exit(status);
-       return status;
+               /*
+                * 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(inode->i_sb,
+                                   "Inode %llu: error after split at cpos %u"
+                                   "trunc len %u, existing record is (%u,%u)",
+                                   (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                                   cpos, len, le32_to_cpu(rec->e_cpos),
+                                   ocfs2_rec_clusters(el, rec));
+                       ret = -EROFS;
+                       goto out;
+               }
+
+               ret = ocfs2_truncate_rec(inode, handle, path, index, dealloc,
+                                        cpos, len);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+       }
+
+out:
+       ocfs2_free_path(path);
+       return ret;
 }
 
-static inline int ocfs2_truncate_log_needs_flush(struct ocfs2_super *osb)
+int ocfs2_truncate_log_needs_flush(struct ocfs2_super *osb)
 {
        struct buffer_head *tl_bh = osb->osb_tl_bh;
        struct ocfs2_dinode *di;
@@ -2489,10 +4503,10 @@ static int ocfs2_truncate_log_can_coalesce(struct ocfs2_truncate_log *tl,
        return current_tail == new_start;
 }
 
-static int ocfs2_truncate_log_append(struct ocfs2_super *osb,
-                                    handle_t *handle,
-                                    u64 start_blk,
-                                    unsigned int num_clusters)
+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;
@@ -2648,7 +4662,7 @@ bail:
 }
 
 /* Expects you to already be holding tl_inode->i_mutex */
-static int __ocfs2_flush_truncate_log(struct ocfs2_super *osb)
+int __ocfs2_flush_truncate_log(struct ocfs2_super *osb)
 {
        int status;
        unsigned int num_to_flush;
@@ -3556,6 +5570,7 @@ static int ocfs2_do_truncate(struct ocfs2_super *osb,
                                      clusters_to_del;
        spin_unlock(&OCFS2_I(inode)->ip_lock);
        le32_add_cpu(&fe->i_clusters, -clusters_to_del);
+       inode->i_blocks = ocfs2_inode_sector_count(inode);
 
        status = ocfs2_trim_tree(inode, path, handle, tc,
                                 clusters_to_del, &delete_blk);
@@ -3618,9 +5633,9 @@ static int ocfs2_ordered_zero_func(handle_t *handle, struct buffer_head *bh)
        return ocfs2_journal_dirty_data(handle, bh);
 }
 
-static void ocfs2_zero_cluster_pages(struct inode *inode, loff_t isize,
-                                    struct page **pages, int numpages,
-                                    u64 phys, handle_t *handle)
+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, ret, partial = 0;
        void *kaddr;
@@ -3633,26 +5648,14 @@ static void ocfs2_zero_cluster_pages(struct inode *inode, loff_t isize,
        if (numpages == 0)
                goto out;
 
-       from = isize & (PAGE_CACHE_SIZE - 1); /* 1st page offset */
-       if (PAGE_CACHE_SHIFT > OCFS2_SB(sb)->s_clustersize_bits) {
-               /*
-                * Since 'from' has been capped to a value below page
-                * size, this calculation won't be able to overflow
-                * 'to'
-                */
-               to = ocfs2_align_bytes_to_clusters(sb, from);
-
-               /*
-                * The truncate tail in this case should never contain
-                * more than one page at maximum. The loop below also
-                * assumes this.
-                */
-               BUG_ON(numpages != 1);
-       }
-
+       to = PAGE_CACHE_SIZE;
        for(i = 0; i < numpages; i++) {
                page = pages[i];
 
+               from = start & (PAGE_CACHE_SIZE - 1);
+               if ((end >> PAGE_CACHE_SHIFT) == page->index)
+                       to = end & (PAGE_CACHE_SIZE - 1);
+
                BUG_ON(from > PAGE_CACHE_SIZE);
                BUG_ON(to > PAGE_CACHE_SIZE);
 
@@ -3689,10 +5692,7 @@ static void ocfs2_zero_cluster_pages(struct inode *inode, loff_t isize,
 
                flush_dcache_page(page);
 
-               /*
-                * Every page after the 1st one should be completely zero'd.
-                */
-               from = 0;
+               start = (page->index + 1) << PAGE_CACHE_SHIFT;
        }
 out:
        if (pages) {
@@ -3705,24 +5705,26 @@ out:
        }
 }
 
-static int ocfs2_grab_eof_pages(struct inode *inode, loff_t isize, struct page **pages,
-                               int *num, u64 *phys)
+static int ocfs2_grab_eof_pages(struct inode *inode, loff_t start, loff_t end,
+                               struct page **pages, int *num, u64 *phys)
 {
        int i, numpages = 0, ret = 0;
-       unsigned int csize = OCFS2_SB(inode->i_sb)->s_clustersize;
        unsigned int ext_flags;
        struct super_block *sb = inode->i_sb;
        struct address_space *mapping = inode->i_mapping;
        unsigned long index;
-       u64 next_cluster_bytes;
+       loff_t last_page_bytes;
 
        BUG_ON(!ocfs2_sparse_alloc(OCFS2_SB(sb)));
+       BUG_ON(start > end);
 
-       /* Cluster boundary, so we don't need to grab any pages. */
-       if ((isize & (csize - 1)) == 0)
+       if (start == end)
                goto out;
 
-       ret = ocfs2_extent_map_get_blocks(inode, isize >> sb->s_blocksize_bits,
+       BUG_ON(start >> OCFS2_SB(sb)->s_clustersize_bits !=
+              (end - 1) >> OCFS2_SB(sb)->s_clustersize_bits);
+
+       ret = ocfs2_extent_map_get_blocks(inode, start >> sb->s_blocksize_bits,
                                          phys, NULL, &ext_flags);
        if (ret) {
                mlog_errno(ret);
@@ -3738,8 +5740,8 @@ static int ocfs2_grab_eof_pages(struct inode *inode, loff_t isize, struct page *
        if (ext_flags & OCFS2_EXT_UNWRITTEN)
                goto out;
 
-       next_cluster_bytes = ocfs2_align_bytes_to_clusters(inode->i_sb, isize);
-       index = isize >> PAGE_CACHE_SHIFT;
+       last_page_bytes = PAGE_ALIGN(end);
+       index = start >> PAGE_CACHE_SHIFT;
        do {
                pages[numpages] = grab_cache_page(mapping, index);
                if (!pages[numpages]) {
@@ -3750,7 +5752,7 @@ static int ocfs2_grab_eof_pages(struct inode *inode, loff_t isize, struct page *
 
                numpages++;
                index++;
-       } while (index < (next_cluster_bytes >> PAGE_CACHE_SHIFT));
+       } while (index < (last_page_bytes >> PAGE_CACHE_SHIFT));
 
 out:
        if (ret != 0) {
@@ -3779,11 +5781,10 @@ out:
  * otherwise block_write_full_page() will skip writeout of pages past
  * i_size. The new_i_size parameter is passed for this reason.
  */
-int ocfs2_zero_tail_for_truncate(struct inode *inode, handle_t *handle,
-                                u64 new_i_size)
+int ocfs2_zero_range_for_truncate(struct inode *inode, handle_t *handle,
+                                 u64 range_start, u64 range_end)
 {
        int ret, numpages;
-       loff_t endbyte;
        struct page **pages = NULL;
        u64 phys;
 
@@ -3802,7 +5803,8 @@ int ocfs2_zero_tail_for_truncate(struct inode *inode, handle_t *handle,
                goto out;
        }
 
-       ret = ocfs2_grab_eof_pages(inode, new_i_size, pages, &numpages, &phys);
+       ret = ocfs2_grab_eof_pages(inode, range_start, range_end, pages,
+                                  &numpages, &phys);
        if (ret) {
                mlog_errno(ret);
                goto out;
@@ -3811,17 +5813,16 @@ int ocfs2_zero_tail_for_truncate(struct inode *inode, handle_t *handle,
        if (numpages == 0)
                goto out;
 
-       ocfs2_zero_cluster_pages(inode, new_i_size, pages, numpages, phys,
-                                handle);
+       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.
         */
-       endbyte = ocfs2_align_bytes_to_clusters(inode->i_sb, new_i_size);
-       ret = do_sync_mapping_range(inode->i_mapping, new_i_size,
-                                   endbyte - 1, SYNC_FILE_RANGE_WRITE);
+       ret = do_sync_mapping_range(inode->i_mapping, range_start,
+                                   range_end - 1, SYNC_FILE_RANGE_WRITE);
        if (ret)
                mlog_errno(ret);