ocfs2: Abstract ocfs2_extent_tree in b-tree operations.

In the old extent tree operation, we take the hypothesis that we
are using the ocfs2_extent_list in ocfs2_dinode as the tree root.
As xattr will also use ocfs2_extent_list to store large value
for a xattr entry, we refactor the tree operation so that xattr
can use it directly.

The refactoring includes 4 steps:
1. Abstract set/get of last_eb_blk and update_clusters since they may
   be stored in different location for dinode and xattr.
2. Add a new structure named ocfs2_extent_tree to indicate the
   extent tree the operation will work on.
3. Remove all the use of fe_bh and di, use root_bh and root_el in
   extent tree instead. So now all the fe_bh is replaced with
   et->root_bh, el with root_el accordingly.
4. Make ocfs2_lock_allocators generic. Now it is limited to be only used
   in file extend allocation. But the whole function is useful when we want
   to store large EAs.

Note: This patch doesn't touch ocfs2_commit_truncate() since it is not used
for anything other than truncate inode data btrees.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

8 files changed, 456 insertions, 288 deletions

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index dc36cd140754..579659bae6c5 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -49,6 +49,143 @@
 
 #include "buffer_head_io.h"
 
+/*
+ * ocfs2_extent_tree and ocfs2_extent_tree_operations are used to abstract
+ * the b-tree operations in ocfs2. Now all the b-tree operations are not
+ * limited to ocfs2_dinode only. Any data which need to allocate clusters
+ * to store can use b-tree. And it only needs to implement its ocfs2_extent_tree
+ * and operation.
+ *
+ * ocfs2_extent_tree contains info for the root of the b-tree, it must have a
+ * root ocfs2_extent_list and a root_bh so that they can be used in the b-tree
+ * functions.
+ * ocfs2_extent_tree_operations abstract the normal operations we do for
+ * the root of extent b-tree.
+ */
+struct ocfs2_extent_tree;
+
+struct ocfs2_extent_tree_operations {
+        void (*set_last_eb_blk) (struct ocfs2_extent_tree *et, u64 blkno);
+        u64 (*get_last_eb_blk) (struct ocfs2_extent_tree *et);
+        void (*update_clusters) (struct inode *inode,
+                                 struct ocfs2_extent_tree *et,
+                                 u32 new_clusters);
+        int (*sanity_check) (struct inode *inode, struct ocfs2_extent_tree *et);
+};
+
+struct ocfs2_extent_tree {
+        enum ocfs2_extent_tree_type type;
+        struct ocfs2_extent_tree_operations *eops;
+        struct buffer_head *root_bh;
+        struct ocfs2_extent_list *root_el;
+};
+
+static void ocfs2_dinode_set_last_eb_blk(struct ocfs2_extent_tree *et,
+                                         u64 blkno)
+{
+        struct ocfs2_dinode *di = (struct ocfs2_dinode *)et->root_bh->b_data;
+
+        BUG_ON(et->type != OCFS2_DINODE_EXTENT);
+        di->i_last_eb_blk = cpu_to_le64(blkno);
+}
+
+static u64 ocfs2_dinode_get_last_eb_blk(struct ocfs2_extent_tree *et)
+{
+        struct ocfs2_dinode *di = (struct ocfs2_dinode *)et->root_bh->b_data;
+
+        BUG_ON(et->type != OCFS2_DINODE_EXTENT);
+        return le64_to_cpu(di->i_last_eb_blk);
+}
+
+static void ocfs2_dinode_update_clusters(struct inode *inode,
+                                         struct ocfs2_extent_tree *et,
+                                         u32 clusters)
+{
+        struct ocfs2_dinode *di =
+                        (struct ocfs2_dinode *)et->root_bh->b_data;
+
+        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 int ocfs2_dinode_sanity_check(struct inode *inode,
+                                     struct ocfs2_extent_tree *et)
+{
+        int ret = 0;
+        struct ocfs2_dinode *di;
+
+        BUG_ON(et->type != OCFS2_DINODE_EXTENT);
+
+        di = (struct ocfs2_dinode *)et->root_bh->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);
+        }
+
+        return ret;
+}
+
+static struct ocfs2_extent_tree_operations ocfs2_dinode_et_ops = {
+        .set_last_eb_blk        = ocfs2_dinode_set_last_eb_blk,
+        .get_last_eb_blk        = ocfs2_dinode_get_last_eb_blk,
+        .update_clusters        = ocfs2_dinode_update_clusters,
+        .sanity_check           = ocfs2_dinode_sanity_check,
+};
+
+static struct ocfs2_extent_tree*
+         ocfs2_new_extent_tree(struct buffer_head *bh,
+                               enum ocfs2_extent_tree_type et_type)
+{
+        struct ocfs2_extent_tree *et;
+
+        et = kzalloc(sizeof(*et), GFP_NOFS);
+        if (!et)
+                return NULL;
+
+        et->type = et_type;
+        get_bh(bh);
+        et->root_bh = bh;
+
+        /* current we only support dinode extent. */
+        BUG_ON(et->type != OCFS2_DINODE_EXTENT);
+        if (et_type == OCFS2_DINODE_EXTENT) {
+                et->root_el = &((struct ocfs2_dinode *)bh->b_data)->id2.i_list;
+                et->eops = &ocfs2_dinode_et_ops;
+        }
+
+        return et;
+}
+
+static void ocfs2_free_extent_tree(struct ocfs2_extent_tree *et)
+{
+        if (et) {
+                brelse(et->root_bh);
+                kfree(et);
+        }
+}
+
+static inline void ocfs2_set_last_eb_blk(struct ocfs2_extent_tree *et,
+                                         u64 new_last_eb_blk)
+{
+        et->eops->set_last_eb_blk(et, new_last_eb_blk);
+}
+
+static inline u64 ocfs2_get_last_eb_blk(struct ocfs2_extent_tree *et)
+{
+        return et->eops->get_last_eb_blk(et);
+}
+
+static inline void ocfs2_update_clusters(struct inode *inode,
+                                         struct ocfs2_extent_tree *et,
+                                         u32 clusters)
+{
+        et->eops->update_clusters(inode, et, clusters);
+}
+
 static void ocfs2_free_truncate_context(struct ocfs2_truncate_context *tc);
 static int ocfs2_cache_extent_block_free(struct ocfs2_cached_dealloc_ctxt *ctxt,
                                          struct ocfs2_extent_block *eb);
@@ -205,17 +342,6 @@ static struct ocfs2_path *ocfs2_new_path(struct buffer_head *root_bh,
 }
 
 /*
- * Allocate and initialize a new path based on a disk inode tree.
- */
-static struct ocfs2_path *ocfs2_new_inode_path(struct buffer_head *di_bh)
-{
-        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
-        struct ocfs2_extent_list *el = &di->id2.i_list;
-
-        return ocfs2_new_path(di_bh, el);
-}
-
-/*
  * Convenience function to journal all components in a path.
  */
 static int ocfs2_journal_access_path(struct inode *inode, handle_t *handle,
@@ -368,24 +494,33 @@ struct ocfs2_merge_ctxt {
  */
 int ocfs2_num_free_extents(struct ocfs2_super *osb,
                            struct inode *inode,
-                           struct buffer_head *bh)
+                           struct buffer_head *root_bh,
+                           enum ocfs2_extent_tree_type type)
 {
         int retval;
-        struct ocfs2_extent_list *el;
+        struct ocfs2_extent_list *el = NULL;
         struct ocfs2_extent_block *eb;
         struct buffer_head *eb_bh = NULL;
-        struct ocfs2_dinode *fe = (struct ocfs2_dinode *)bh->b_data;
+        u64 last_eb_blk = 0;
 
         mlog_entry_void();
 
-        if (!OCFS2_IS_VALID_DINODE(fe)) {
-                OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, fe);
-                retval = -EIO;
-                goto bail;
+        if (type == OCFS2_DINODE_EXTENT) {
+                struct ocfs2_dinode *fe =
+                                (struct ocfs2_dinode *)root_bh->b_data;
+                if (!OCFS2_IS_VALID_DINODE(fe)) {
+                        OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, fe);
+                        retval = -EIO;
+                        goto bail;
+                }
+
+                if (fe->i_last_eb_blk)
+                        last_eb_blk = le64_to_cpu(fe->i_last_eb_blk);
+                el = &fe->id2.i_list;
         }
 
-        if (fe->i_last_eb_blk) {
-                retval = ocfs2_read_block(osb, le64_to_cpu(fe->i_last_eb_blk),
+        if (last_eb_blk) {
+                retval = ocfs2_read_block(osb, last_eb_blk,
                                           &eb_bh, OCFS2_BH_CACHED, inode);
                 if (retval < 0) {
                         mlog_errno(retval);
@@ -393,8 +528,7 @@ int ocfs2_num_free_extents(struct ocfs2_super *osb,
                 }
                 eb = (struct ocfs2_extent_block *) eb_bh->b_data;
                 el = &eb->h_list;
-        } else
-                el = &fe->id2.i_list;
+        }
 
         BUG_ON(el->l_tree_depth != 0);
 
@@ -532,7 +666,7 @@ static inline u32 ocfs2_sum_rightmost_rec(struct ocfs2_extent_list  *el)
 static int ocfs2_add_branch(struct ocfs2_super *osb,
                             handle_t *handle,
                             struct inode *inode,
-                            struct buffer_head *fe_bh,
+                            struct ocfs2_extent_tree *et,
                             struct buffer_head *eb_bh,
                             struct buffer_head **last_eb_bh,
                             struct ocfs2_alloc_context *meta_ac)
@@ -541,7 +675,6 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
         u64 next_blkno, new_last_eb_blk;
         struct buffer_head *bh;
         struct buffer_head **new_eb_bhs = NULL;
-        struct ocfs2_dinode *fe;
         struct ocfs2_extent_block *eb;
         struct ocfs2_extent_list  *eb_el;
         struct ocfs2_extent_list  *el;
@@ -551,13 +684,11 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
 
         BUG_ON(!last_eb_bh || !*last_eb_bh);
 
-        fe = (struct ocfs2_dinode *) fe_bh->b_data;
-
         if (eb_bh) {
                 eb = (struct ocfs2_extent_block *) eb_bh->b_data;
                 el = &eb->h_list;
         } else
-                el = &fe->id2.i_list;
+                el = et->root_el;
 
         /* we never add a branch to a leaf. */
         BUG_ON(!el->l_tree_depth);
@@ -647,7 +778,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
                 mlog_errno(status);
                 goto bail;
         }
-        status = ocfs2_journal_access(handle, inode, fe_bh,
+        status = ocfs2_journal_access(handle, inode, et->root_bh,
                                       OCFS2_JOURNAL_ACCESS_WRITE);
         if (status < 0) {
                 mlog_errno(status);
@@ -663,7 +794,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
         }
 
         /* Link the new branch into the rest of the tree (el will
-         * either be on the fe, or the extent block passed in. */
+         * either be on the root_bh, or the extent block passed in. */
         i = le16_to_cpu(el->l_next_free_rec);
         el->l_recs[i].e_blkno = cpu_to_le64(next_blkno);
         el->l_recs[i].e_cpos = cpu_to_le32(new_cpos);
@@ -672,7 +803,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
 
         /* fe needs a new last extent block pointer, as does the
          * next_leaf on the previously last-extent-block. */
-        fe->i_last_eb_blk = cpu_to_le64(new_last_eb_blk);
+        ocfs2_set_last_eb_blk(et, new_last_eb_blk);
 
         eb = (struct ocfs2_extent_block *) (*last_eb_bh)->b_data;
         eb->h_next_leaf_blk = cpu_to_le64(new_last_eb_blk);
@@ -680,7 +811,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
         status = ocfs2_journal_dirty(handle, *last_eb_bh);
         if (status < 0)
                 mlog_errno(status);
-        status = ocfs2_journal_dirty(handle, fe_bh);
+        status = ocfs2_journal_dirty(handle, et->root_bh);
         if (status < 0)
                 mlog_errno(status);
         if (eb_bh) {
@@ -718,16 +849,15 @@ bail:
 static int ocfs2_shift_tree_depth(struct ocfs2_super *osb,
                                   handle_t *handle,
                                   struct inode *inode,
-                                  struct buffer_head *fe_bh,
+                                  struct ocfs2_extent_tree *et,
                                   struct ocfs2_alloc_context *meta_ac,
                                   struct buffer_head **ret_new_eb_bh)
 {
         int status, i;
         u32 new_clusters;
         struct buffer_head *new_eb_bh = NULL;
-        struct ocfs2_dinode *fe;
         struct ocfs2_extent_block *eb;
-        struct ocfs2_extent_list  *fe_el;
+        struct ocfs2_extent_list  *root_el;
         struct ocfs2_extent_list  *eb_el;
 
         mlog_entry_void();
@@ -747,8 +877,7 @@ static int ocfs2_shift_tree_depth(struct ocfs2_super *osb,
         }
 
         eb_el = &eb->h_list;
-        fe = (struct ocfs2_dinode *) fe_bh->b_data;
-        fe_el = &fe->id2.i_list;
+        root_el = et->root_el;
 
         status = ocfs2_journal_access(handle, inode, new_eb_bh,
                                       OCFS2_JOURNAL_ACCESS_CREATE);
@@ -757,11 +886,11 @@ static int ocfs2_shift_tree_depth(struct ocfs2_super *osb,
                 goto bail;
         }
 
-        /* copy the fe data into the new extent block */
-        eb_el->l_tree_depth = fe_el->l_tree_depth;
-        eb_el->l_next_free_rec = fe_el->l_next_free_rec;
-        for(i = 0; i < le16_to_cpu(fe_el->l_next_free_rec); i++)
-                eb_el->l_recs[i] = fe_el->l_recs[i];
+        /* copy the root extent list data into the new extent block */
+        eb_el->l_tree_depth = root_el->l_tree_depth;
+        eb_el->l_next_free_rec = root_el->l_next_free_rec;
+        for (i = 0; i < le16_to_cpu(root_el->l_next_free_rec); i++)
+                eb_el->l_recs[i] = root_el->l_recs[i];
 
         status = ocfs2_journal_dirty(handle, new_eb_bh);
         if (status < 0) {
@@ -769,7 +898,7 @@ static int ocfs2_shift_tree_depth(struct ocfs2_super *osb,
                 goto bail;
         }
 
-        status = ocfs2_journal_access(handle, inode, fe_bh,
+        status = ocfs2_journal_access(handle, inode, et->root_bh,
                                       OCFS2_JOURNAL_ACCESS_WRITE);
         if (status < 0) {
                 mlog_errno(status);
@@ -778,21 +907,21 @@ static int ocfs2_shift_tree_depth(struct ocfs2_super *osb,
 
         new_clusters = ocfs2_sum_rightmost_rec(eb_el);
 
-        /* update fe now */
-        le16_add_cpu(&fe_el->l_tree_depth, 1);
-        fe_el->l_recs[0].e_cpos = 0;
-        fe_el->l_recs[0].e_blkno = eb->h_blkno;
-        fe_el->l_recs[0].e_int_clusters = cpu_to_le32(new_clusters);
-        for(i = 1; i < le16_to_cpu(fe_el->l_next_free_rec); i++)
-                memset(&fe_el->l_recs[i], 0, sizeof(struct ocfs2_extent_rec));
-        fe_el->l_next_free_rec = cpu_to_le16(1);
+        /* update root_bh now */
+        le16_add_cpu(&root_el->l_tree_depth, 1);
+        root_el->l_recs[0].e_cpos = 0;
+        root_el->l_recs[0].e_blkno = eb->h_blkno;
+        root_el->l_recs[0].e_int_clusters = cpu_to_le32(new_clusters);
+        for (i = 1; i < le16_to_cpu(root_el->l_next_free_rec); i++)
+                memset(&root_el->l_recs[i], 0, sizeof(struct ocfs2_extent_rec));
+        root_el->l_next_free_rec = cpu_to_le16(1);
 
         /* If this is our 1st tree depth shift, then last_eb_blk
          * becomes the allocated extent block */
-        if (fe_el->l_tree_depth == cpu_to_le16(1))
-                fe->i_last_eb_blk = eb->h_blkno;
+        if (root_el->l_tree_depth == cpu_to_le16(1))
+                ocfs2_set_last_eb_blk(et, le64_to_cpu(eb->h_blkno));
 
-        status = ocfs2_journal_dirty(handle, fe_bh);
+        status = ocfs2_journal_dirty(handle, et->root_bh);
         if (status < 0) {
                 mlog_errno(status);
                 goto bail;
@@ -818,22 +947,21 @@ bail:
  * 1) a lowest extent block is found, then we pass it back in
  *    *lowest_eb_bh and return '0'
  *
- * 2) the search fails to find anything, but the dinode has room. We
+ * 2) the search fails to find anything, but the root_el has room. We
  *    pass NULL back in *lowest_eb_bh, but still return '0'
  *
- * 3) the search fails to find anything AND the dinode is full, in
+ * 3) the search fails to find anything AND the root_el is full, in
  *    which case we return > 0
  *
  * return status < 0 indicates an error.
  */
 static int ocfs2_find_branch_target(struct ocfs2_super *osb,
                                     struct inode *inode,
-                                    struct buffer_head *fe_bh,
+                                    struct ocfs2_extent_tree *et,
                                     struct buffer_head **target_bh)
 {
         int status = 0, i;
         u64 blkno;
-        struct ocfs2_dinode *fe;
         struct ocfs2_extent_block *eb;
         struct ocfs2_extent_list  *el;
         struct buffer_head *bh = NULL;
@@ -843,8 +971,7 @@ static int ocfs2_find_branch_target(struct ocfs2_super *osb,
 
         *target_bh = NULL;
 
-        fe = (struct ocfs2_dinode *) fe_bh->b_data;
-        el = &fe->id2.i_list;
+        el = et->root_el;
 
         while(le16_to_cpu(el->l_tree_depth) > 1) {
                 if (le16_to_cpu(el->l_next_free_rec) == 0) {
@@ -896,8 +1023,8 @@ static int ocfs2_find_branch_target(struct ocfs2_super *osb,
 
         /* If we didn't find one and the fe doesn't have any room,
          * then return '1' */
-        if (!lowest_bh
-            && (fe->id2.i_list.l_next_free_rec == fe->id2.i_list.l_count))
+        el = et->root_el;
+        if (!lowest_bh && (el->l_next_free_rec == el->l_count))
                 status = 1;
 
         *target_bh = lowest_bh;
@@ -920,19 +1047,19 @@ bail:
  * *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 ocfs2_extent_tree *et, int *final_depth,
                            struct buffer_head **last_eb_bh,
                            struct ocfs2_alloc_context *meta_ac)
 {
         int ret, shift;
-        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
-        int depth = le16_to_cpu(di->id2.i_list.l_tree_depth);
+        struct ocfs2_extent_list *el = et->root_el;
+        int depth = le16_to_cpu(el->l_tree_depth);
         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
         struct buffer_head *bh = NULL;
 
         BUG_ON(meta_ac == NULL);
 
-        shift = ocfs2_find_branch_target(osb, inode, di_bh, &bh);
+        shift = ocfs2_find_branch_target(osb, inode, et, &bh);
         if (shift < 0) {
                 ret = shift;
                 mlog_errno(ret);
@@ -949,7 +1076,7 @@ static int ocfs2_grow_tree(struct inode *inode, handle_t *handle,
                 /* ocfs2_shift_tree_depth will return us a buffer with
                  * the new extent block (so we can pass that to
                  * ocfs2_add_branch). */
-                ret = ocfs2_shift_tree_depth(osb, handle, inode, di_bh,
+                ret = ocfs2_shift_tree_depth(osb, handle, inode, et,
                                              meta_ac, &bh);
                 if (ret < 0) {
                         mlog_errno(ret);
@@ -976,7 +1103,7 @@ static int ocfs2_grow_tree(struct inode *inode, handle_t *handle,
         /* call ocfs2_add_branch to add the final part of the tree with
          * the new data. */
         mlog(0, "add branch. bh = %p\n", bh);
-        ret = ocfs2_add_branch(osb, handle, inode, di_bh, bh, last_eb_bh,
+        ret = ocfs2_add_branch(osb, handle, inode, et, bh, last_eb_bh,
                                meta_ac);
         if (ret < 0) {
                 mlog_errno(ret);
@@ -2059,11 +2186,11 @@ static int ocfs2_rotate_subtree_left(struct inode *inode, handle_t *handle,
                                      struct ocfs2_path *right_path,
                                      int subtree_index,
                                      struct ocfs2_cached_dealloc_ctxt *dealloc,
-                                     int *deleted)
+                                     int *deleted,
+                                     struct ocfs2_extent_tree *et)
 {
         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 buffer_head *root_bh, *et_root_bh = path_root_bh(right_path);
         struct ocfs2_extent_list *right_leaf_el, *left_leaf_el;
         struct ocfs2_extent_block *eb;
 
@@ -2115,7 +2242,7 @@ static int ocfs2_rotate_subtree_left(struct inode *inode, handle_t *handle,
                  * We have to update i_last_eb_blk during the meta
                  * data delete.
                  */
-                ret = ocfs2_journal_access(handle, inode, di_bh,
+                ret = ocfs2_journal_access(handle, inode, et_root_bh,
                                            OCFS2_JOURNAL_ACCESS_WRITE);
                 if (ret) {
                         mlog_errno(ret);
@@ -2190,7 +2317,7 @@ static int ocfs2_rotate_subtree_left(struct inode *inode, handle_t *handle,
                 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;
+                ocfs2_set_last_eb_blk(et, le64_to_cpu(eb->h_blkno));
 
                 /*
                  * Removal of the extent in the left leaf was skipped
@@ -2200,7 +2327,7 @@ static int ocfs2_rotate_subtree_left(struct inode *inode, handle_t *handle,
                 if (right_has_empty)
                         ocfs2_remove_empty_extent(left_leaf_el);
 
-                ret = ocfs2_journal_dirty(handle, di_bh);
+                ret = ocfs2_journal_dirty(handle, et_root_bh);
                 if (ret)
                         mlog_errno(ret);
 
@@ -2323,7 +2450,8 @@ 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)
+                                    struct ocfs2_path **empty_extent_path,
+                                    struct ocfs2_extent_tree *et)
 {
         int ret, subtree_root, deleted;
         u32 right_cpos;
@@ -2396,7 +2524,7 @@ static int __ocfs2_rotate_tree_left(struct inode *inode,
 
                 ret = ocfs2_rotate_subtree_left(inode, handle, left_path,
                                                 right_path, subtree_root,
-                                                dealloc, &deleted);
+                                                dealloc, &deleted, et);
                 if (ret == -EAGAIN) {
                         /*
                          * The rotation has to temporarily stop due to
@@ -2439,29 +2567,20 @@ out:
 }
 
 static int ocfs2_remove_rightmost_path(struct inode *inode, handle_t *handle,
-                                       struct ocfs2_path *path,
-                                       struct ocfs2_cached_dealloc_ctxt *dealloc)
+                                struct ocfs2_path *path,
+                                struct ocfs2_cached_dealloc_ctxt *dealloc,
+                                struct ocfs2_extent_tree *et)
 {
         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;
-        }
 
+        ret = et->eops->sanity_check(inode, et);
+        if (ret)
+                goto out;
         /*
          * There's two ways we handle this depending on
          * whether path is the only existing one.
@@ -2518,7 +2637,7 @@ static int ocfs2_remove_rightmost_path(struct inode *inode, handle_t *handle,
                 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;
+                ocfs2_set_last_eb_blk(et, le64_to_cpu(eb->h_blkno));
         } else {
                 /*
                  * 'path' is also the leftmost path which
@@ -2529,12 +2648,12 @@ static int ocfs2_remove_rightmost_path(struct inode *inode, handle_t *handle,
                  */
                 ocfs2_unlink_path(inode, handle, dealloc, path, 1);
 
-                el = &di->id2.i_list;
+                el = et->root_el;
                 el->l_tree_depth = 0;
                 el->l_next_free_rec = 0;
                 memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
 
-                di->i_last_eb_blk = 0;
+                ocfs2_set_last_eb_blk(et, 0);
         }
 
         ocfs2_journal_dirty(handle, path_root_bh(path));
@@ -2562,7 +2681,8 @@ out:
  */
 static int ocfs2_rotate_tree_left(struct inode *inode, handle_t *handle,
                                   struct ocfs2_path *path,
-                                  struct ocfs2_cached_dealloc_ctxt *dealloc)
+                                  struct ocfs2_cached_dealloc_ctxt *dealloc,
+                                  struct ocfs2_extent_tree *et)
 {
         int ret, orig_credits = handle->h_buffer_credits;
         struct ocfs2_path *tmp_path = NULL, *restart_path = NULL;
@@ -2576,7 +2696,7 @@ static int ocfs2_rotate_tree_left(struct inode *inode, handle_t *handle,
         if (path->p_tree_depth == 0) {
 rightmost_no_delete:
                 /*
-                 * In-inode extents. This is trivially handled, so do
+                 * Inline extents. This is trivially handled, so do
                  * it up front.
                  */
                 ret = ocfs2_rotate_rightmost_leaf_left(inode, handle,
@@ -2630,7 +2750,7 @@ rightmost_no_delete:
                  */
 
                 ret = ocfs2_remove_rightmost_path(inode, handle, path,
-                                                  dealloc);
+                                                  dealloc, et);
                 if (ret)
                         mlog_errno(ret);
                 goto out;
@@ -2642,7 +2762,7 @@ rightmost_no_delete:
          */
 try_rotate:
         ret = __ocfs2_rotate_tree_left(inode, handle, orig_credits, path,
-                                       dealloc, &restart_path);
+                                       dealloc, &restart_path, et);
         if (ret && ret != -EAGAIN) {
                 mlog_errno(ret);
                 goto out;
@@ -2654,7 +2774,7 @@ try_rotate:
 
                 ret = __ocfs2_rotate_tree_left(inode, handle, orig_credits,
                                                tmp_path, dealloc,
-                                               &restart_path);
+                                               &restart_path, et);
                 if (ret && ret != -EAGAIN) {
                         mlog_errno(ret);
                         goto out;
@@ -2940,6 +3060,7 @@ static int ocfs2_merge_rec_left(struct inode *inode,
                                 handle_t *handle,
                                 struct ocfs2_extent_rec *split_rec,
                                 struct ocfs2_cached_dealloc_ctxt *dealloc,
+                                struct ocfs2_extent_tree *et,
                                 int index)
 {
         int ret, i, subtree_index = 0, has_empty_extent = 0;
@@ -3060,7 +3181,8 @@ static int ocfs2_merge_rec_left(struct inode *inode,
                     le16_to_cpu(el->l_next_free_rec) == 1) {
 
                         ret = ocfs2_remove_rightmost_path(inode, handle,
-                                                          right_path, dealloc);
+                                                          right_path,
+                                                          dealloc, et);
                         if (ret) {
                                 mlog_errno(ret);
                                 goto out;
@@ -3087,7 +3209,8 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
                                      int split_index,
                                      struct ocfs2_extent_rec *split_rec,
                                      struct ocfs2_cached_dealloc_ctxt *dealloc,
-                                     struct ocfs2_merge_ctxt *ctxt)
+                                     struct ocfs2_merge_ctxt *ctxt,
+                                     struct ocfs2_extent_tree *et)
 
 {
         int ret = 0;
@@ -3105,7 +3228,7 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
                  * illegal.
                  */
                 ret = ocfs2_rotate_tree_left(inode, handle, path,
-                                             dealloc);
+                                             dealloc, et);
                 if (ret) {
                         mlog_errno(ret);
                         goto out;
@@ -3148,7 +3271,8 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
                 BUG_ON(!ocfs2_is_empty_extent(&el->l_recs[0]));
 
                 /* The merge left us with an empty extent, remove it. */
-                ret = ocfs2_rotate_tree_left(inode, handle, path, dealloc);
+                ret = ocfs2_rotate_tree_left(inode, handle, path,
+                                             dealloc, et);
                 if (ret) {
                         mlog_errno(ret);
                         goto out;
@@ -3162,7 +3286,7 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
                  */
                 ret = ocfs2_merge_rec_left(inode, path,
                                            handle, rec,
-                                           dealloc,
+                                           dealloc, et,
                                            split_index);
 
                 if (ret) {
@@ -3171,7 +3295,7 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
                 }
 
                 ret = ocfs2_rotate_tree_left(inode, handle, path,
-                                             dealloc);
+                                             dealloc, et);
                 /*
                  * Error from this last rotate is not critical, so
                  * print but don't bubble it up.
@@ -3191,7 +3315,7 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
                         ret = ocfs2_merge_rec_left(inode,
                                                    path,
                                                    handle, split_rec,
-                                                   dealloc,
+                                                   dealloc, et,
                                                    split_index);
                         if (ret) {
                                 mlog_errno(ret);
@@ -3214,7 +3338,7 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
                          * our leaf. Try to rotate it away.
                          */
                         ret = ocfs2_rotate_tree_left(inode, handle, path,
-                                                     dealloc);
+                                                     dealloc, et);
                         if (ret)
                                 mlog_errno(ret);
                         ret = 0;
@@ -3348,16 +3472,6 @@ rotate:
         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,
@@ -3559,8 +3673,8 @@ static void ocfs2_split_record(struct inode *inode,
 }
 
 /*
- * This function only does inserts on an allocation b-tree. For dinode
- * lists, ocfs2_insert_at_leaf() is called directly.
+ * This function only does inserts on an allocation b-tree. For tree
+ * depth = 0, ocfs2_insert_at_leaf() is called directly.
  *
  * right_path is the path we want to do the actual insert
  * in. left_path should only be passed in if we need to update that
@@ -3657,7 +3771,7 @@ out:
 
 static int ocfs2_do_insert_extent(struct inode *inode,
                                   handle_t *handle,
-                                  struct buffer_head *di_bh,
+                                  struct ocfs2_extent_tree *et,
                                   struct ocfs2_extent_rec *insert_rec,
                                   struct ocfs2_insert_type *type)
 {
@@ -3665,13 +3779,11 @@ static int ocfs2_do_insert_extent(struct inode *inode,
         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;
+        el = et->root_el;
 
-        ret = ocfs2_journal_access(handle, inode, di_bh,
+        ret = ocfs2_journal_access(handle, inode, et->root_bh,
                                    OCFS2_JOURNAL_ACCESS_WRITE);
         if (ret) {
                 mlog_errno(ret);
@@ -3683,7 +3795,7 @@ static int ocfs2_do_insert_extent(struct inode *inode,
                 goto out_update_clusters;
         }
 
-        right_path = ocfs2_new_inode_path(di_bh);
+        right_path = ocfs2_new_path(et->root_bh, et->root_el);
         if (!right_path) {
                 ret = -ENOMEM;
                 mlog_errno(ret);
@@ -3733,7 +3845,7 @@ static int ocfs2_do_insert_extent(struct inode *inode,
                  * ocfs2_rotate_tree_right() might have extended the
                  * transaction without re-journaling our tree root.
                  */
-                ret = ocfs2_journal_access(handle, inode, di_bh,
+                ret = ocfs2_journal_access(handle, inode, et->root_bh,
                                            OCFS2_JOURNAL_ACCESS_WRITE);
                 if (ret) {
                         mlog_errno(ret);
@@ -3758,10 +3870,10 @@ static int ocfs2_do_insert_extent(struct inode *inode,
 
 out_update_clusters:
         if (type->ins_split == SPLIT_NONE)
-                ocfs2_update_dinode_clusters(inode, di,
-                                             le16_to_cpu(insert_rec->e_leaf_clusters));
+                ocfs2_update_clusters(inode, et,
+                                      le16_to_cpu(insert_rec->e_leaf_clusters));
 
-        ret = ocfs2_journal_dirty(handle, di_bh);
+        ret = ocfs2_journal_dirty(handle, et->root_bh);
         if (ret)
                 mlog_errno(ret);
 
@@ -3915,8 +4027,8 @@ static void ocfs2_figure_contig_type(struct inode *inode,
  * 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
+ * This should also work against the root extent list for tree's with 0
+ * depth. If we consider the root extent list to be the rightmost leaf node
  * then the logic here makes sense.
  */
 static void ocfs2_figure_appending_type(struct ocfs2_insert_type *insert,
@@ -3967,14 +4079,13 @@ set_tail_append:
  * structure.
  */
 static int ocfs2_figure_insert_type(struct inode *inode,
-                                    struct buffer_head *di_bh,
+                                    struct ocfs2_extent_tree *et,
                                     struct buffer_head **last_eb_bh,
                                     struct ocfs2_extent_rec *insert_rec,
                                     int *free_records,
                                     struct ocfs2_insert_type *insert)
 {
         int ret;
-        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
         struct ocfs2_extent_block *eb;
         struct ocfs2_extent_list *el;
         struct ocfs2_path *path = NULL;
@@ -3982,7 +4093,7 @@ static int ocfs2_figure_insert_type(struct inode *inode,
 
         insert->ins_split = SPLIT_NONE;
 
-        el = &di->id2.i_list;
+        el = et->root_el;
         insert->ins_tree_depth = le16_to_cpu(el->l_tree_depth);
 
         if (el->l_tree_depth) {
@@ -3993,7 +4104,7 @@ static int ocfs2_figure_insert_type(struct inode *inode,
                  * may want it later.
                  */
                 ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
-                                       le64_to_cpu(di->i_last_eb_blk), &bh,
+                                       ocfs2_get_last_eb_blk(et), &bh,
                                        OCFS2_BH_CACHED, inode);
                 if (ret) {
                         mlog_exit(ret);
@@ -4020,7 +4131,7 @@ static int ocfs2_figure_insert_type(struct inode *inode,
                 return 0;
         }
 
-        path = ocfs2_new_inode_path(di_bh);
+        path = ocfs2_new_path(et->root_bh, et->root_el);
         if (!path) {
                 ret = -ENOMEM;
                 mlog_errno(ret);
@@ -4070,7 +4181,8 @@ static int ocfs2_figure_insert_type(struct inode *inode,
          * 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) {
+        if (ocfs2_get_last_eb_blk(et) ==
+            path_leaf_bh(path)->b_blocknr) {
                 /*
                  * Ok, ocfs2_find_path() returned us the rightmost
                  * tree path. This might be an appending insert. There are
@@ -4100,21 +4212,30 @@ out:
 int ocfs2_insert_extent(struct ocfs2_super *osb,
                         handle_t *handle,
                         struct inode *inode,
-                        struct buffer_head *fe_bh,
+                        struct buffer_head *root_bh,
                         u32 cpos,
                         u64 start_blk,
                         u32 new_clusters,
                         u8 flags,
-                        struct ocfs2_alloc_context *meta_ac)
+                        struct ocfs2_alloc_context *meta_ac,
+                        enum ocfs2_extent_tree_type et_type)
 {
         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;
+        struct ocfs2_extent_tree *et = NULL;
 
         BUG_ON(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL);
 
+        et = ocfs2_new_extent_tree(root_bh, et_type);
+        if (!et) {
+                status = -ENOMEM;
+                mlog_errno(status);
+                goto bail;
+        }
+
         mlog(0, "add %u clusters at position %u to inode %llu\n",
              new_clusters, cpos, (unsigned long long)OCFS2_I(inode)->ip_blkno);
 
@@ -4132,7 +4253,7 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
         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,
+        status = ocfs2_figure_insert_type(inode, et, &last_eb_bh, &rec,
                                           &free_records, &insert);
         if (status < 0) {
                 mlog_errno(status);
@@ -4146,7 +4267,7 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
              free_records, insert.ins_tree_depth);
 
         if (insert.ins_contig == CONTIG_NONE && free_records == 0) {
-                status = ocfs2_grow_tree(inode, handle, fe_bh,
+                status = ocfs2_grow_tree(inode, handle, et,
                                          &insert.ins_tree_depth, &last_eb_bh,
                                          meta_ac);
                 if (status) {
@@ -4156,16 +4277,18 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
         }
 
         /* Finally, we can add clusters. This might rotate the tree for us. */
-        status = ocfs2_do_insert_extent(inode, handle, fe_bh, &rec, &insert);
+        status = ocfs2_do_insert_extent(inode, handle, et, &rec, &insert);
         if (status < 0)
                 mlog_errno(status);
-        else
+        else if (et->type == OCFS2_DINODE_EXTENT)
                 ocfs2_extent_map_insert_rec(inode, &rec);
 
 bail:
         if (last_eb_bh)
                 brelse(last_eb_bh);
 
+        if (et)
+                ocfs2_free_extent_tree(et);
         mlog_exit(status);
         return status;
 }
@@ -4193,7 +4316,7 @@ static void ocfs2_make_right_split_rec(struct super_block *sb,
 static int ocfs2_split_and_insert(struct inode *inode,
                                   handle_t *handle,
                                   struct ocfs2_path *path,
-                                  struct buffer_head *di_bh,
+                                  struct ocfs2_extent_tree *et,
                                   struct buffer_head **last_eb_bh,
                                   int split_index,
                                   struct ocfs2_extent_rec *orig_split_rec,
@@ -4207,7 +4330,6 @@ static int ocfs2_split_and_insert(struct inode *inode,
         struct ocfs2_extent_rec split_rec = *orig_split_rec;
         struct ocfs2_insert_type insert;
         struct ocfs2_extent_block *eb;
-        struct ocfs2_dinode *di;
 
 leftright:
         /*
@@ -4216,8 +4338,7 @@ leftright:
          */
         rec = path_leaf_el(path)->l_recs[split_index];
 
-        di = (struct ocfs2_dinode *)di_bh->b_data;
-        rightmost_el = &di->id2.i_list;
+        rightmost_el = et->root_el;
 
         depth = le16_to_cpu(rightmost_el->l_tree_depth);
         if (depth) {
@@ -4228,8 +4349,8 @@ leftright:
 
         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);
+                ret = ocfs2_grow_tree(inode, handle, et,
+                                      &depth, last_eb_bh, meta_ac);
                 if (ret) {
                         mlog_errno(ret);
                         goto out;
@@ -4266,8 +4387,7 @@ leftright:
                 do_leftright = 1;
         }
 
-        ret = ocfs2_do_insert_extent(inode, handle, di_bh, &split_rec,
-                                     &insert);
+        ret = ocfs2_do_insert_extent(inode, handle, et, &split_rec, &insert);
         if (ret) {
                 mlog_errno(ret);
                 goto out;
@@ -4309,8 +4429,9 @@ out:
  * 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.
+ * last_eb_bh should be the rightmost leaf block for any extent
+ * btree. Since a split may grow the tree or a merge might shrink it,
+ * the caller cannot trust the contents of that buffer after this call.
  *
  * This code is optimized for readability - several passes might be
  * made over certain portions of the tree. All of those blocks will
@@ -4318,7 +4439,7 @@ out:
  * extra overhead is not expressed in terms of disk reads.
  */
 static int __ocfs2_mark_extent_written(struct inode *inode,
-                                       struct buffer_head *di_bh,
+                                       struct ocfs2_extent_tree *et,
                                        handle_t *handle,
                                        struct ocfs2_path *path,
                                        int split_index,
@@ -4358,10 +4479,9 @@ static int __ocfs2_mark_extent_written(struct inode *inode,
          */
         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),
+                                       ocfs2_get_last_eb_blk(et),
                                        &last_eb_bh, OCFS2_BH_CACHED, inode);
                 if (ret) {
                         mlog_exit(ret);
@@ -4395,7 +4515,7 @@ static int __ocfs2_mark_extent_written(struct inode *inode,
                 if (ctxt.c_split_covers_rec)
                         el->l_recs[split_index] = *split_rec;
                 else
-                        ret = ocfs2_split_and_insert(inode, handle, path, di_bh,
+                        ret = ocfs2_split_and_insert(inode, handle, path, et,
                                                      &last_eb_bh, split_index,
                                                      split_rec, meta_ac);
                 if (ret)
@@ -4403,7 +4523,7 @@ static int __ocfs2_mark_extent_written(struct inode *inode,
         } else {
                 ret = ocfs2_try_to_merge_extent(inode, handle, path,
                                                 split_index, split_rec,
-                                                dealloc, &ctxt);
+                                                dealloc, &ctxt, et);
                 if (ret)
                         mlog_errno(ret);
         }
@@ -4421,16 +4541,18 @@ out:
  *
  * The caller is responsible for passing down meta_ac if we'll need it.
  */
-int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *di_bh,
+int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *root_bh,
                               handle_t *handle, u32 cpos, u32 len, u32 phys,
                               struct ocfs2_alloc_context *meta_ac,
-                              struct ocfs2_cached_dealloc_ctxt *dealloc)
+                              struct ocfs2_cached_dealloc_ctxt *dealloc,
+                              enum ocfs2_extent_tree_type et_type)
 {
         int ret, index;
         u64 start_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys);
         struct ocfs2_extent_rec split_rec;
         struct ocfs2_path *left_path = NULL;
         struct ocfs2_extent_list *el;
+        struct ocfs2_extent_tree *et = NULL;
 
         mlog(0, "Inode %lu cpos %u, len %u, phys %u (%llu)\n",
              inode->i_ino, cpos, len, phys, (unsigned long long)start_blkno);
@@ -4444,13 +4566,21 @@ int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *di_bh,
                 goto out;
         }
 
+        et = ocfs2_new_extent_tree(root_bh, et_type);
+        if (!et) {
+                ret = -ENOMEM;
+                mlog_errno(ret);
+                goto out;
+        }
+
         /*
          * XXX: This should be fixed up so that we just re-insert the
          * next extent records.
          */
-        ocfs2_extent_map_trunc(inode, 0);
+        if (et_type == OCFS2_DINODE_EXTENT)
+                ocfs2_extent_map_trunc(inode, 0);
 
-        left_path = ocfs2_new_inode_path(di_bh);
+        left_path = ocfs2_new_path(et->root_bh, et->root_el);
         if (!left_path) {
                 ret = -ENOMEM;
                 mlog_errno(ret);
@@ -4481,23 +4611,25 @@ int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *di_bh,
         split_rec.e_flags = path_leaf_el(left_path)->l_recs[index].e_flags;
         split_rec.e_flags &= ~OCFS2_EXT_UNWRITTEN;
 
-        ret = __ocfs2_mark_extent_written(inode, di_bh, handle, left_path,
-                                          index, &split_rec, meta_ac, dealloc);
+        ret = __ocfs2_mark_extent_written(inode, et, handle, left_path,
+                                          index, &split_rec, meta_ac,
+                                          dealloc);
         if (ret)
                 mlog_errno(ret);
 
 out:
         ocfs2_free_path(left_path);
+        if (et)
+                ocfs2_free_extent_tree(et);
         return ret;
 }
 
-static int ocfs2_split_tree(struct inode *inode, struct buffer_head *di_bh,
+static int ocfs2_split_tree(struct inode *inode, struct ocfs2_extent_tree *et,
                             handle_t *handle, struct ocfs2_path *path,
                             int index, u32 new_range,
                             struct ocfs2_alloc_context *meta_ac)
 {
         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;
@@ -4515,7 +4647,7 @@ static int ocfs2_split_tree(struct inode *inode, struct buffer_head *di_bh,
         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),
+                                       ocfs2_get_last_eb_blk(et),
                                        &last_eb_bh, OCFS2_BH_CACHED, inode);
                 if (ret < 0) {
                         mlog_errno(ret);
@@ -4528,7 +4660,7 @@ static int ocfs2_split_tree(struct inode *inode, struct buffer_head *di_bh,
                 rightmost_el = path_leaf_el(path);
 
         credits += path->p_tree_depth +
-                   ocfs2_extend_meta_needed(&di->id2.i_list);
+                   ocfs2_extend_meta_needed(et->root_el);
         ret = ocfs2_extend_trans(handle, credits);
         if (ret) {
                 mlog_errno(ret);
@@ -4537,7 +4669,7 @@ static int ocfs2_split_tree(struct inode *inode, struct buffer_head *di_bh,
 
         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,
+                ret = ocfs2_grow_tree(inode, handle, et, &depth, &last_eb_bh,
                                       meta_ac);
                 if (ret) {
                         mlog_errno(ret);
@@ -4551,7 +4683,7 @@ static int ocfs2_split_tree(struct inode *inode, struct buffer_head *di_bh,
         insert.ins_split = SPLIT_RIGHT;
         insert.ins_tree_depth = depth;
 
-        ret = ocfs2_do_insert_extent(inode, handle, di_bh, &split_rec, &insert);
+        ret = ocfs2_do_insert_extent(inode, handle, et, &split_rec, &insert);
         if (ret)
                 mlog_errno(ret);
 
@@ -4563,7 +4695,8 @@ out:
 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)
+                              u32 cpos, u32 len,
+                              struct ocfs2_extent_tree *et)
 {
         int ret;
         u32 left_cpos, rec_range, trunc_range;
@@ -4575,7 +4708,7 @@ static int ocfs2_truncate_rec(struct inode *inode, handle_t *handle,
         struct ocfs2_extent_block *eb;
 
         if (ocfs2_is_empty_extent(&el->l_recs[0]) && index > 0) {
-                ret = ocfs2_rotate_tree_left(inode, handle, path, dealloc);
+                ret = ocfs2_rotate_tree_left(inode, handle, path, dealloc, et);
                 if (ret) {
                         mlog_errno(ret);
                         goto out;
@@ -4706,7 +4839,7 @@ static int ocfs2_truncate_rec(struct inode *inode, handle_t *handle,
 
         ocfs2_journal_dirty(handle, path_leaf_bh(path));
 
-        ret = ocfs2_rotate_tree_left(inode, handle, path, dealloc);
+        ret = ocfs2_rotate_tree_left(inode, handle, path, dealloc, et);
         if (ret) {
                 mlog_errno(ret);
                 goto out;
@@ -4717,20 +4850,29 @@ out:
         return ret;
 }
 
-int ocfs2_remove_extent(struct inode *inode, struct buffer_head *di_bh,
+int ocfs2_remove_extent(struct inode *inode, struct buffer_head *root_bh,
                         u32 cpos, u32 len, handle_t *handle,
                         struct ocfs2_alloc_context *meta_ac,
-                        struct ocfs2_cached_dealloc_ctxt *dealloc)
+                        struct ocfs2_cached_dealloc_ctxt *dealloc,
+                        enum ocfs2_extent_tree_type et_type)
 {
         int ret, index;
         u32 rec_range, trunc_range;
         struct ocfs2_extent_rec *rec;
         struct ocfs2_extent_list *el;
-        struct ocfs2_path *path;
+        struct ocfs2_path *path = NULL;
+        struct ocfs2_extent_tree *et = NULL;
+
+        et = ocfs2_new_extent_tree(root_bh, et_type);
+        if (!et) {
+                ret = -ENOMEM;
+                mlog_errno(ret);
+                goto out;
+        }
 
         ocfs2_extent_map_trunc(inode, 0);
 
-        path = ocfs2_new_inode_path(di_bh);
+        path = ocfs2_new_path(et->root_bh, et->root_el);
         if (!path) {
                 ret = -ENOMEM;
                 mlog_errno(ret);
@@ -4783,13 +4925,13 @@ int ocfs2_remove_extent(struct inode *inode, struct buffer_head *di_bh,
 
         if (le32_to_cpu(rec->e_cpos) == cpos || rec_range == trunc_range) {
                 ret = ocfs2_truncate_rec(inode, handle, path, index, dealloc,
-                                         cpos, len);
+                                         cpos, len, et);
                 if (ret) {
                         mlog_errno(ret);
                         goto out;
                 }
         } else {
-                ret = ocfs2_split_tree(inode, di_bh, handle, path, index,
+                ret = ocfs2_split_tree(inode, et, handle, path, index,
                                        trunc_range, meta_ac);
                 if (ret) {
                         mlog_errno(ret);
@@ -4838,7 +4980,7 @@ int ocfs2_remove_extent(struct inode *inode, struct buffer_head *di_bh,
                 }
 
                 ret = ocfs2_truncate_rec(inode, handle, path, index, dealloc,
-                                         cpos, len);
+                                         cpos, len, et);
                 if (ret) {
                         mlog_errno(ret);
                         goto out;
@@ -4847,6 +4989,8 @@ int ocfs2_remove_extent(struct inode *inode, struct buffer_head *di_bh,
 
 out:
         ocfs2_free_path(path);
+        if (et)
+                ocfs2_free_extent_tree(et);
         return ret;
 }
 
@@ -6355,7 +6499,8 @@ int ocfs2_convert_inline_data_to_extents(struct inode *inode,
                  * the in-inode data from our pages.
                  */
                 ret = ocfs2_insert_extent(osb, handle, inode, di_bh,
-                                          0, block, 1, 0, NULL);
+                                          0, block, 1, 0,
+                                          NULL, OCFS2_DINODE_EXTENT);
                 if (ret) {
                         mlog_errno(ret);
                         goto out_commit;
@@ -6397,13 +6542,14 @@ int ocfs2_commit_truncate(struct ocfs2_super *osb,
         handle_t *handle = NULL;
         struct inode *tl_inode = osb->osb_tl_inode;
         struct ocfs2_path *path = NULL;
+        struct ocfs2_dinode *di = (struct ocfs2_dinode *)fe_bh->b_data;
 
         mlog_entry_void();
 
         new_highest_cpos = ocfs2_clusters_for_bytes(osb->sb,
                                                      i_size_read(inode));
 
-        path = ocfs2_new_inode_path(fe_bh);
+        path = ocfs2_new_path(fe_bh, &di->id2.i_list);
         if (!path) {
                 status = -ENOMEM;
                 mlog_errno(status);
diff --git a/fs/ocfs2/alloc.h b/fs/ocfs2/alloc.h
index a0e334f10cd1..473c8bcc62fb 100644
--- a/fs/ocfs2/alloc.h
+++ b/fs/ocfs2/alloc.h
@@ -26,28 +26,37 @@
 #ifndef OCFS2_ALLOC_H
 #define OCFS2_ALLOC_H
 
+enum ocfs2_extent_tree_type {
+        OCFS2_DINODE_EXTENT = 0,
+};
+
 struct ocfs2_alloc_context;
 int ocfs2_insert_extent(struct ocfs2_super *osb,
                         handle_t *handle,
                         struct inode *inode,
-                        struct buffer_head *fe_bh,
+                        struct buffer_head *root_bh,
                         u32 cpos,
                         u64 start_blk,
                         u32 new_clusters,
                         u8 flags,
-                        struct ocfs2_alloc_context *meta_ac);
+                        struct ocfs2_alloc_context *meta_ac,
+                        enum ocfs2_extent_tree_type et_type);
 struct ocfs2_cached_dealloc_ctxt;
-int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *di_bh,
+int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *root_bh,
                               handle_t *handle, u32 cpos, u32 len, u32 phys,
                               struct ocfs2_alloc_context *meta_ac,
-                              struct ocfs2_cached_dealloc_ctxt *dealloc);
-int ocfs2_remove_extent(struct inode *inode, struct buffer_head *di_bh,
+                              struct ocfs2_cached_dealloc_ctxt *dealloc,
+                              enum ocfs2_extent_tree_type et_type);
+int ocfs2_remove_extent(struct inode *inode, struct buffer_head *root_bh,
                         u32 cpos, u32 len, handle_t *handle,
                         struct ocfs2_alloc_context *meta_ac,
-                        struct ocfs2_cached_dealloc_ctxt *dealloc);
+                        struct ocfs2_cached_dealloc_ctxt *dealloc,
+                        enum ocfs2_extent_tree_type et_type);
 int ocfs2_num_free_extents(struct ocfs2_super *osb,
                            struct inode *inode,
-                           struct buffer_head *bh);
+                           struct buffer_head *root_bh,
+                           enum ocfs2_extent_tree_type et_type);
+
 /*
  * how many new metadata chunks would an allocation need at maximum?
  *
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index bbe3f8b2d0e2..44ea5eb3fdc4 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -1278,7 +1278,8 @@ static int ocfs2_write_cluster(struct address_space *mapping,
         } else if (unwritten) {
                 ret = ocfs2_mark_extent_written(inode, wc->w_di_bh,
                                                 wc->w_handle, cpos, 1, phys,
-                                                meta_ac, &wc->w_dealloc);
+                                                meta_ac, &wc->w_dealloc,
+                                                OCFS2_DINODE_EXTENT);
                 if (ret < 0) {
                         mlog_errno(ret);
                         goto out;
@@ -1712,7 +1713,13 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
                  * ocfs2_lock_allocators(). It greatly over-estimates
                  * the work to be done.
                  */
-                ret = ocfs2_lock_allocators(inode, wc->w_di_bh,
+                mlog(0, "extend inode %llu, i_size = %lld, di->i_clusters = %u,"
+                     " clusters_to_add = %u, extents_to_split = %u\n",
+                     (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                     (long long)i_size_read(inode), le32_to_cpu(di->i_clusters),
+                     clusters_to_alloc, extents_to_split);
+
+                ret = ocfs2_lock_allocators(inode, wc->w_di_bh, &di->id2.i_list,
                                             clusters_to_alloc, extents_to_split,
                                             &data_ac, &meta_ac);
                 if (ret) {
diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index 126aa219c0c1..ba0fb9e16264 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -1306,7 +1306,7 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
          * related blocks have been journaled already.
          */
         ret = ocfs2_insert_extent(osb, handle, dir, di_bh, 0, blkno, len, 0,
-                                  NULL);
+                                  NULL, OCFS2_DINODE_EXTENT);
         if (ret) {
                 mlog_errno(ret);
                 goto out_commit;
@@ -1338,7 +1338,7 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
                 blkno = ocfs2_clusters_to_blocks(dir->i_sb, bit_off);
 
                 ret = ocfs2_insert_extent(osb, handle, dir, di_bh, 1, blkno,
-                                          len, 0, NULL);
+                                          len, 0, NULL, OCFS2_DINODE_EXTENT);
                 if (ret) {
                         mlog_errno(ret);
                         goto out_commit;
@@ -1481,7 +1481,8 @@ static int ocfs2_extend_dir(struct ocfs2_super *osb,
         if (dir_i_size == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters)) {
                 spin_unlock(&OCFS2_I(dir)->ip_lock);
                 num_free_extents = ocfs2_num_free_extents(osb, dir,
-                                                          parent_fe_bh);
+                                                          parent_fe_bh,
+                                                          OCFS2_DINODE_EXTENT);
                 if (num_free_extents < 0) {
                         status = num_free_extents;
                         mlog_errno(status);
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index a31bba6c5575..f567cc53d9bc 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -521,7 +521,8 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
         if (mark_unwritten)
                 flags = OCFS2_EXT_UNWRITTEN;
 
-        free_extents = ocfs2_num_free_extents(osb, inode, fe_bh);
+        free_extents = ocfs2_num_free_extents(osb, inode, fe_bh,
+                                              OCFS2_DINODE_EXTENT);
         if (free_extents < 0) {
                 status = free_extents;
                 mlog_errno(status);
@@ -570,7 +571,7 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
              num_bits, bit_off, (unsigned long long)OCFS2_I(inode)->ip_blkno);
         status = ocfs2_insert_extent(osb, handle, inode, fe_bh,
                                      *logical_offset, block, num_bits,
-                                     flags, meta_ac);
+                                     flags, meta_ac, OCFS2_DINODE_EXTENT);
         if (status < 0) {
                 mlog_errno(status);
                 goto leave;
@@ -599,92 +600,6 @@ leave:
         return status;
 }
 
-/*
- * For a given allocation, determine which allocators will need to be
- * accessed, and lock them, reserving the appropriate number of bits.
- *
- * Sparse file systems call this from ocfs2_write_begin_nolock()
- * and ocfs2_allocate_unwritten_extents().
- *
- * File systems which don't support holes call this from
- * ocfs2_extend_allocation().
- */
-int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *di_bh,
-                          u32 clusters_to_add, u32 extents_to_split,
-                          struct ocfs2_alloc_context **data_ac,
-                          struct ocfs2_alloc_context **meta_ac)
-{
-        int ret = 0, num_free_extents;
-        unsigned int max_recs_needed = clusters_to_add + 2 * extents_to_split;
-        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
-        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
-
-        *meta_ac = NULL;
-        if (data_ac)
-                *data_ac = NULL;
-
-        BUG_ON(clusters_to_add != 0 && data_ac == NULL);
-
-        mlog(0, "extend inode %llu, i_size = %lld, di->i_clusters = %u, "
-             "clusters_to_add = %u, extents_to_split = %u\n",
-             (unsigned long long)OCFS2_I(inode)->ip_blkno, (long long)i_size_read(inode),
-             le32_to_cpu(di->i_clusters), clusters_to_add, extents_to_split);
-
-        num_free_extents = ocfs2_num_free_extents(osb, inode, di_bh);
-        if (num_free_extents < 0) {
-                ret = num_free_extents;
-                mlog_errno(ret);
-                goto out;
-        }
-
-        /*
-         * Sparse allocation file systems need to be more conservative
-         * with reserving room for expansion - the actual allocation
-         * happens while we've got a journal handle open so re-taking
-         * a cluster lock (because we ran out of room for another
-         * extent) will violate ordering rules.
-         *
-         * Most of the time we'll only be seeing this 1 cluster at a time
-         * anyway.
-         *
-         * Always lock for any unwritten extents - we might want to
-         * add blocks during a split.
-         */
-        if (!num_free_extents ||
-            (ocfs2_sparse_alloc(osb) && num_free_extents < max_recs_needed)) {
-                ret = ocfs2_reserve_new_metadata(osb, &di->id2.i_list, meta_ac);
-                if (ret < 0) {
-                        if (ret != -ENOSPC)
-                                mlog_errno(ret);
-                        goto out;
-                }
-        }
-
-        if (clusters_to_add == 0)
-                goto out;
-
-        ret = ocfs2_reserve_clusters(osb, clusters_to_add, data_ac);
-        if (ret < 0) {
-                if (ret != -ENOSPC)
-                        mlog_errno(ret);
-                goto out;
-        }
-
-out:
-        if (ret) {
-                if (*meta_ac) {
-                        ocfs2_free_alloc_context(*meta_ac);
-                        *meta_ac = NULL;
-                }
-
-                /*
-                 * We cannot have an error and a non null *data_ac.
-                 */
-        }
-
-        return ret;
-}
-
 static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
                                      u32 clusters_to_add, int mark_unwritten)
 {
@@ -725,7 +640,13 @@ static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
 restart_all:
         BUG_ON(le32_to_cpu(fe->i_clusters) != OCFS2_I(inode)->ip_clusters);
 
-        status = ocfs2_lock_allocators(inode, bh, clusters_to_add, 0, &data_ac,
+        mlog(0, "extend inode %llu, i_size = %lld, di->i_clusters = %u, "
+             "clusters_to_add = %u\n",
+             (unsigned long long)OCFS2_I(inode)->ip_blkno,
+             (long long)i_size_read(inode), le32_to_cpu(fe->i_clusters),
+             clusters_to_add);
+        status = ocfs2_lock_allocators(inode, bh, &fe->id2.i_list,
+                                       clusters_to_add, 0, &data_ac,
                                        &meta_ac);
         if (status) {
                 mlog_errno(status);
@@ -1397,7 +1318,8 @@ static int __ocfs2_remove_inode_range(struct inode *inode,
         struct ocfs2_alloc_context *meta_ac = NULL;
         struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
 
-        ret = ocfs2_lock_allocators(inode, di_bh, 0, 1, NULL, &meta_ac);
+        ret = ocfs2_lock_allocators(inode, di_bh, &di->id2.i_list,
+                                    0, 1, NULL, &meta_ac);
         if (ret) {
                 mlog_errno(ret);
                 return ret;
@@ -1428,7 +1350,7 @@ static int __ocfs2_remove_inode_range(struct inode *inode,
         }
 
         ret = ocfs2_remove_extent(inode, di_bh, cpos, len, handle, meta_ac,
-                                  dealloc);
+                                  dealloc, OCFS2_DINODE_EXTENT);
         if (ret) {
                 mlog_errno(ret);
                 goto out_commit;
diff --git a/fs/ocfs2/file.h b/fs/ocfs2/file.h
index c96b8054fbe7..18e5c80cc737 100644
--- a/fs/ocfs2/file.h
+++ b/fs/ocfs2/file.h
@@ -57,10 +57,6 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
                                enum ocfs2_alloc_restarted *reason_ret);
 int ocfs2_extend_no_holes(struct inode *inode, u64 new_i_size,
                           u64 zero_to);
-int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *fe,
-                          u32 clusters_to_add, u32 extents_to_split,
-                          struct ocfs2_alloc_context **data_ac,
-                          struct ocfs2_alloc_context **meta_ac);
 int ocfs2_setattr(struct dentry *dentry, struct iattr *attr);
 int ocfs2_getattr(struct vfsmount *mnt, struct dentry *dentry,
                   struct kstat *stat);
diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 2a817bca1ddb..b642c825fb7c 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -1894,3 +1894,85 @@ static inline void ocfs2_debug_suballoc_inode(struct ocfs2_dinode *fe)
                        (unsigned long long)fe->id2.i_chain.cl_recs[i].c_blkno);
         }
 }
+
+/*
+ * For a given allocation, determine which allocators will need to be
+ * accessed, and lock them, reserving the appropriate number of bits.
+ *
+ * Sparse file systems call this from ocfs2_write_begin_nolock()
+ * and ocfs2_allocate_unwritten_extents().
+ *
+ * File systems which don't support holes call this from
+ * ocfs2_extend_allocation().
+ */
+int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *root_bh,
+                          struct ocfs2_extent_list *root_el,
+                          u32 clusters_to_add, u32 extents_to_split,
+                          struct ocfs2_alloc_context **data_ac,
+                          struct ocfs2_alloc_context **meta_ac)
+{
+        int ret = 0, num_free_extents;
+        unsigned int max_recs_needed = clusters_to_add + 2 * extents_to_split;
+        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+        *meta_ac = NULL;
+        if (data_ac)
+                *data_ac = NULL;
+
+        BUG_ON(clusters_to_add != 0 && data_ac == NULL);
+
+        num_free_extents = ocfs2_num_free_extents(osb, inode, root_bh,
+                                                  OCFS2_DINODE_EXTENT);
+        if (num_free_extents < 0) {
+                ret = num_free_extents;
+                mlog_errno(ret);
+                goto out;
+        }
+
+        /*
+         * Sparse allocation file systems need to be more conservative
+         * with reserving room for expansion - the actual allocation
+         * happens while we've got a journal handle open so re-taking
+         * a cluster lock (because we ran out of room for another
+         * extent) will violate ordering rules.
+         *
+         * Most of the time we'll only be seeing this 1 cluster at a time
+         * anyway.
+         *
+         * Always lock for any unwritten extents - we might want to
+         * add blocks during a split.
+         */
+        if (!num_free_extents ||
+            (ocfs2_sparse_alloc(osb) && num_free_extents < max_recs_needed)) {
+                ret = ocfs2_reserve_new_metadata(osb, root_el, meta_ac);
+                if (ret < 0) {
+                        if (ret != -ENOSPC)
+                                mlog_errno(ret);
+                        goto out;
+                }
+        }
+
+        if (clusters_to_add == 0)
+                goto out;
+
+        ret = ocfs2_reserve_clusters(osb, clusters_to_add, data_ac);
+        if (ret < 0) {
+                if (ret != -ENOSPC)
+                        mlog_errno(ret);
+                goto out;
+        }
+
+out:
+        if (ret) {
+                if (*meta_ac) {
+                        ocfs2_free_alloc_context(*meta_ac);
+                        *meta_ac = NULL;
+                }
+
+                /*
+                 * We cannot have an error and a non null *data_ac.
+                 */
+        }
+
+        return ret;
+}
diff --git a/fs/ocfs2/suballoc.h b/fs/ocfs2/suballoc.h
index 3f96c875bcf7..a3e531e62df2 100644
--- a/fs/ocfs2/suballoc.h
+++ b/fs/ocfs2/suballoc.h
@@ -162,4 +162,9 @@ u64 ocfs2_which_cluster_group(struct inode *inode, u32 cluster);
 int ocfs2_check_group_descriptor(struct super_block *sb,
                                  struct ocfs2_dinode *di,
                                  struct ocfs2_group_desc *gd);
+int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *root_bh,
+                          struct ocfs2_extent_list *root_el,
+                          u32 clusters_to_add, u32 extents_to_split,
+                          struct ocfs2_alloc_context **data_ac,
+                          struct ocfs2_alloc_context **meta_ac);
 #endif /* _CHAINALLOC_H_ */