ocfs2: take ip_alloc_sem during entire truncate
[sfrench/cifs-2.6.git] / fs / ocfs2 / alloc.c
index edc91ca3792ac2b331a33540ec8d5a8250f24566..02b6e7af8edbdd077d8e567506e2fbcd56519d9f 100644 (file)
@@ -27,6 +27,7 @@
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/highmem.h>
+#include <linux/swap.h>
 
 #define MLOG_MASK_PREFIX ML_DISK_ALLOC
 #include <cluster/masklog.h>
@@ -34,6 +35,7 @@
 #include "ocfs2.h"
 
 #include "alloc.h"
+#include "aops.h"
 #include "dlmglue.h"
 #include "extent_map.h"
 #include "inode.h"
 
 #include "buffer_head_io.h"
 
-static int ocfs2_extent_contig(struct inode *inode,
-                              struct ocfs2_extent_rec *ext,
-                              u64 blkno);
+static void ocfs2_free_truncate_context(struct ocfs2_truncate_context *tc);
 
-static int ocfs2_create_new_meta_bhs(struct ocfs2_super *osb,
-                                    handle_t *handle,
-                                    struct inode *inode,
-                                    int wanted,
-                                    struct ocfs2_alloc_context *meta_ac,
-                                    struct buffer_head *bhs[]);
+/*
+ * Structures which describe a path through a btree, and functions to
+ * manipulate them.
+ *
+ * The idea here is to be as generic as possible with the tree
+ * manipulation code.
+ */
+struct ocfs2_path_item {
+       struct buffer_head              *bh;
+       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 buffer_head *eb_bh,
-                           struct buffer_head *last_eb_bh,
-                           struct ocfs2_alloc_context *meta_ac);
+#define OCFS2_MAX_PATH_DEPTH   5
 
-static int ocfs2_shift_tree_depth(struct ocfs2_super *osb,
-                                 handle_t *handle,
-                                 struct inode *inode,
-                                 struct buffer_head *fe_bh,
-                                 struct ocfs2_alloc_context *meta_ac,
-                                 struct buffer_head **ret_new_eb_bh);
+struct ocfs2_path {
+       int                     p_tree_depth;
+       struct ocfs2_path_item  p_node[OCFS2_MAX_PATH_DEPTH];
+};
 
-static int ocfs2_do_insert_extent(struct ocfs2_super *osb,
-                                 handle_t *handle,
-                                 struct inode *inode,
-                                 struct buffer_head *fe_bh,
-                                 u64 blkno,
-                                 u32 new_clusters);
+#define path_root_bh(_path) ((_path)->p_node[0].bh)
+#define path_root_el(_path) ((_path)->p_node[0].el)
+#define path_leaf_bh(_path) ((_path)->p_node[(_path)->p_tree_depth].bh)
+#define path_leaf_el(_path) ((_path)->p_node[(_path)->p_tree_depth].el)
+#define path_num_items(_path) ((_path)->p_tree_depth + 1)
 
-static int ocfs2_find_branch_target(struct ocfs2_super *osb,
-                                   struct inode *inode,
-                                   struct buffer_head *fe_bh,
-                                   struct buffer_head **target_bh);
+/*
+ * Reset the actual path elements so that we can re-use the structure
+ * to build another path. Generally, this involves freeing the buffer
+ * heads.
+ */
+static void ocfs2_reinit_path(struct ocfs2_path *path, int keep_root)
+{
+       int i, start = 0, depth = 0;
+       struct ocfs2_path_item *node;
 
-static int ocfs2_find_new_last_ext_blk(struct ocfs2_super *osb,
-                                      struct inode *inode,
-                                      struct ocfs2_dinode *fe,
-                                      unsigned int new_i_clusters,
-                                      struct buffer_head *old_last_eb,
-                                      struct buffer_head **new_last_eb);
+       if (keep_root)
+               start = 1;
 
-static void ocfs2_free_truncate_context(struct ocfs2_truncate_context *tc);
+       for(i = start; i < path_num_items(path); i++) {
+               node = &path->p_node[i];
+
+               brelse(node->bh);
+               node->bh = NULL;
+               node->el = NULL;
+       }
+
+       /*
+        * Tree depth may change during truncate, or insert. If we're
+        * keeping the root extent list, then make sure that our path
+        * structure reflects the proper depth.
+        */
+       if (keep_root)
+               depth = le16_to_cpu(path_root_el(path)->l_tree_depth);
+
+       path->p_tree_depth = depth;
+}
+
+static void ocfs2_free_path(struct ocfs2_path *path)
+{
+       if (path) {
+               ocfs2_reinit_path(path, 0);
+               kfree(path);
+       }
+}
+
+/*
+ * Make the *dest path the same as src and re-initialize src path to
+ * have a root only.
+ */
+static void ocfs2_mv_path(struct ocfs2_path *dest, struct ocfs2_path *src)
+{
+       int i;
+
+       BUG_ON(path_root_bh(dest) != path_root_bh(src));
+
+       for(i = 1; i < OCFS2_MAX_PATH_DEPTH; i++) {
+               brelse(dest->p_node[i].bh);
+
+               dest->p_node[i].bh = src->p_node[i].bh;
+               dest->p_node[i].el = src->p_node[i].el;
+
+               src->p_node[i].bh = NULL;
+               src->p_node[i].el = NULL;
+       }
+}
+
+/*
+ * Insert an extent block at given index.
+ *
+ * This will not take an additional reference on eb_bh.
+ */
+static inline void ocfs2_path_insert_eb(struct ocfs2_path *path, int index,
+                                       struct buffer_head *eb_bh)
+{
+       struct ocfs2_extent_block *eb = (struct ocfs2_extent_block *)eb_bh->b_data;
+
+       /*
+        * Right now, no root bh is an extent block, so this helps
+        * catch code errors with dinode trees. The assertion can be
+        * safely removed if we ever need to insert extent block
+        * structures at the root.
+        */
+       BUG_ON(index == 0);
+
+       path->p_node[index].bh = eb_bh;
+       path->p_node[index].el = &eb->h_list;
+}
+
+static struct ocfs2_path *ocfs2_new_path(struct buffer_head *root_bh,
+                                        struct ocfs2_extent_list *root_el)
+{
+       struct ocfs2_path *path;
 
-static int ocfs2_extent_contig(struct inode *inode,
-                              struct ocfs2_extent_rec *ext,
-                              u64 blkno)
+       BUG_ON(le16_to_cpu(root_el->l_tree_depth) >= OCFS2_MAX_PATH_DEPTH);
+
+       path = kzalloc(sizeof(*path), GFP_NOFS);
+       if (path) {
+               path->p_tree_depth = le16_to_cpu(root_el->l_tree_depth);
+               get_bh(root_bh);
+               path_root_bh(path) = root_bh;
+               path_root_el(path) = root_el;
+       }
+
+       return path;
+}
+
+/*
+ * 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,
+                                    struct ocfs2_path *path)
+{
+       int i, ret = 0;
+
+       if (!path)
+               goto out;
+
+       for(i = 0; i < path_num_items(path); i++) {
+               ret = ocfs2_journal_access(handle, inode, path->p_node[i].bh,
+                                          OCFS2_JOURNAL_ACCESS_WRITE);
+               if (ret < 0) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+       }
+
+out:
+       return ret;
+}
+
+enum ocfs2_contig_type {
+       CONTIG_NONE = 0,
+       CONTIG_LEFT,
+       CONTIG_RIGHT
+};
+
+
+/*
+ * NOTE: ocfs2_block_extent_contig(), ocfs2_extents_adjacent() and
+ * ocfs2_extent_contig only work properly against leaf nodes!
+ */
+static int ocfs2_block_extent_contig(struct super_block *sb,
+                                    struct ocfs2_extent_rec *ext,
+                                    u64 blkno)
+{
+       u64 blk_end = le64_to_cpu(ext->e_blkno);
+
+       blk_end += ocfs2_clusters_to_blocks(sb,
+                                   le16_to_cpu(ext->e_leaf_clusters));
+
+       return blkno == blk_end;
+}
+
+static int ocfs2_extents_adjacent(struct ocfs2_extent_rec *left,
+                                 struct ocfs2_extent_rec *right)
 {
-       return blkno == (le64_to_cpu(ext->e_blkno) +
-                        ocfs2_clusters_to_blocks(inode->i_sb,
-                                                 le32_to_cpu(ext->e_clusters)));
+       u32 left_range;
+
+       left_range = le32_to_cpu(left->e_cpos) +
+               le16_to_cpu(left->e_leaf_clusters);
+
+       return (left_range == le32_to_cpu(right->e_cpos));
+}
+
+static enum ocfs2_contig_type
+       ocfs2_extent_contig(struct inode *inode,
+                           struct ocfs2_extent_rec *ext,
+                           struct ocfs2_extent_rec *insert_rec)
+{
+       u64 blkno = le64_to_cpu(insert_rec->e_blkno);
+
+       if (ocfs2_extents_adjacent(ext, insert_rec) &&
+           ocfs2_block_extent_contig(inode->i_sb, ext, blkno))
+                       return CONTIG_RIGHT;
+
+       blkno = le64_to_cpu(ext->e_blkno);
+       if (ocfs2_extents_adjacent(insert_rec, ext) &&
+           ocfs2_block_extent_contig(inode->i_sb, insert_rec, blkno))
+               return CONTIG_LEFT;
+
+       return CONTIG_NONE;
 }
 
+/*
+ * NOTE: We can have pretty much any combination of contiguousness and
+ * appending.
+ *
+ * The usefulness of APPEND_TAIL is more in that it lets us know that
+ * we'll have to update the path to that leaf.
+ */
+enum ocfs2_append_type {
+       APPEND_NONE = 0,
+       APPEND_TAIL,
+};
+
+struct ocfs2_insert_type {
+       enum ocfs2_append_type  ins_appending;
+       enum ocfs2_contig_type  ins_contig;
+       int                     ins_contig_index;
+       int                     ins_free_records;
+       int                     ins_tree_depth;
+};
+
 /*
  * How many free extents have we got before we need more meta data?
  */
@@ -241,6 +423,28 @@ bail:
        return status;
 }
 
+/*
+ * Helper function for ocfs2_add_branch() and ocfs2_shift_tree_depth().
+ *
+ * Returns the sum of the rightmost extent rec logical offset and
+ * cluster count.
+ *
+ * ocfs2_add_branch() uses this to determine what logical cluster
+ * value should be populated into the leftmost new branch records.
+ *
+ * ocfs2_shift_tree_depth() uses this to determine the # clusters
+ * value for the new topmost tree record.
+ */
+static inline u32 ocfs2_sum_rightmost_rec(struct ocfs2_extent_list  *el)
+{
+       int i;
+
+       i = le16_to_cpu(el->l_next_free_rec) - 1;
+
+       return le32_to_cpu(el->l_recs[i].e_cpos) +
+               ocfs2_rec_clusters(el, &el->l_recs[i]);
+}
+
 /*
  * Add an entire tree branch to our inode. eb_bh is the extent block
  * to start at, if we don't want to start the branch at the dinode
@@ -250,7 +454,7 @@ bail:
  * for the new last extent block.
  *
  * the new branch will be 'empty' in the sense that every block will
- * contain a single record with e_clusters == 0.
+ * contain a single record with cluster count == 0.
  */
 static int ocfs2_add_branch(struct ocfs2_super *osb,
                            handle_t *handle,
@@ -268,6 +472,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
        struct ocfs2_extent_block *eb;
        struct ocfs2_extent_list  *eb_el;
        struct ocfs2_extent_list  *el;
+       u32 new_cpos;
 
        mlog_entry_void();
 
@@ -302,6 +507,9 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
                goto bail;
        }
 
+       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
         * linked with the rest of the tree.
         * conversly, new_eb_bhs[0] is the new bottommost leaf.
@@ -330,9 +538,18 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
                eb->h_next_leaf_blk = 0;
                eb_el->l_tree_depth = cpu_to_le16(i);
                eb_el->l_next_free_rec = cpu_to_le16(1);
-               eb_el->l_recs[0].e_cpos = fe->i_clusters;
+               /*
+                * This actually counts as an empty extent as
+                * c_clusters == 0
+                */
+               eb_el->l_recs[0].e_cpos = cpu_to_le32(new_cpos);
                eb_el->l_recs[0].e_blkno = cpu_to_le64(next_blkno);
-               eb_el->l_recs[0].e_clusters = cpu_to_le32(0);
+               /*
+                * eb_el isn't always an interior node, but even leaf
+                * nodes want a zero'd flags and reserved field so
+                * this gets the whole 32 bits regardless of use.
+                */
+               eb_el->l_recs[0].e_int_clusters = cpu_to_le32(0);
                if (!eb_el->l_tree_depth)
                        new_last_eb_blk = le64_to_cpu(eb->h_blkno);
 
@@ -376,8 +593,8 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
         * either be on the fe, 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 = fe->i_clusters;
-       el->l_recs[i].e_clusters = 0;
+       el->l_recs[i].e_cpos = cpu_to_le32(new_cpos);
+       el->l_recs[i].e_int_clusters = 0;
        le16_add_cpu(&el->l_next_free_rec, 1);
 
        /* fe needs a new last extent block pointer, as does the
@@ -425,6 +642,7 @@ static int ocfs2_shift_tree_depth(struct ocfs2_super *osb,
                                  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;
@@ -461,11 +679,8 @@ static int ocfs2_shift_tree_depth(struct ocfs2_super *osb,
        /* 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].e_cpos = fe_el->l_recs[i].e_cpos;
-               eb_el->l_recs[i].e_clusters = fe_el->l_recs[i].e_clusters;
-               eb_el->l_recs[i].e_blkno = fe_el->l_recs[i].e_blkno;
-       }
+       for(i = 0; i < le16_to_cpu(fe_el->l_next_free_rec); i++)
+               eb_el->l_recs[i] = fe_el->l_recs[i];
 
        status = ocfs2_journal_dirty(handle, new_eb_bh);
        if (status < 0) {
@@ -480,16 +695,15 @@ static int ocfs2_shift_tree_depth(struct ocfs2_super *osb,
                goto bail;
        }
 
+       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_clusters = fe->i_clusters;
-       for(i = 1; i < le16_to_cpu(fe_el->l_next_free_rec); i++) {
-               fe_el->l_recs[i].e_cpos = 0;
-               fe_el->l_recs[i].e_clusters = 0;
-               fe_el->l_recs[i].e_blkno = 0;
-       }
+       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);
 
        /* If this is our 1st tree depth shift, then last_eb_blk
@@ -514,199 +728,6 @@ bail:
        return status;
 }
 
-/*
- * Expects the tree to already have room in the rightmost leaf for the
- * extent.  Updates all the extent blocks (and the dinode) on the way
- * down.
- */
-static int ocfs2_do_insert_extent(struct ocfs2_super *osb,
-                                 handle_t *handle,
-                                 struct inode *inode,
-                                 struct buffer_head *fe_bh,
-                                 u64 start_blk,
-                                 u32 new_clusters)
-{
-       int status, i, num_bhs = 0;
-       u64 next_blkno;
-       u16 next_free;
-       struct buffer_head **eb_bhs = NULL;
-       struct ocfs2_dinode *fe;
-       struct ocfs2_extent_block *eb;
-       struct ocfs2_extent_list  *el;
-
-       mlog_entry_void();
-
-       status = ocfs2_journal_access(handle, inode, fe_bh,
-                                     OCFS2_JOURNAL_ACCESS_WRITE);
-       if (status < 0) {
-               mlog_errno(status);
-               goto bail;
-       }
-
-       fe = (struct ocfs2_dinode *) fe_bh->b_data;
-       el = &fe->id2.i_list;
-       if (el->l_tree_depth) {
-               /* This is another operation where we want to be
-                * careful about our tree updates. An error here means
-                * none of the previous changes we made should roll
-                * forward. As a result, we have to record the buffers
-                * for this part of the tree in an array and reserve a
-                * journal write to them before making any changes. */
-               num_bhs = le16_to_cpu(fe->id2.i_list.l_tree_depth);
-               eb_bhs = kcalloc(num_bhs, sizeof(struct buffer_head *),
-                                GFP_KERNEL);
-               if (!eb_bhs) {
-                       status = -ENOMEM;
-                       mlog_errno(status);
-                       goto bail;
-               }
-
-               i = 0;
-               while(el->l_tree_depth) {
-                       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);
-                               status = -EIO;
-                               goto bail;
-                       }
-                       next_blkno = le64_to_cpu(el->l_recs[next_free - 1].e_blkno);
-
-                       BUG_ON(i >= num_bhs);
-                       status = ocfs2_read_block(osb, next_blkno, &eb_bhs[i],
-                                                 OCFS2_BH_CACHED, inode);
-                       if (status < 0) {
-                               mlog_errno(status);
-                               goto bail;
-                       }
-                       eb = (struct ocfs2_extent_block *) eb_bhs[i]->b_data;
-                       if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
-                               OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb,
-                                                                eb);
-                               status = -EIO;
-                               goto bail;
-                       }
-
-                       status = ocfs2_journal_access(handle, inode, eb_bhs[i],
-                                                     OCFS2_JOURNAL_ACCESS_WRITE);
-                       if (status < 0) {
-                               mlog_errno(status);
-                               goto bail;
-                       }
-
-                       el = &eb->h_list;
-                       i++;
-                       /* When we leave this loop, eb_bhs[num_bhs - 1] will
-                        * hold the bottom-most leaf extent block. */
-               }
-               BUG_ON(el->l_tree_depth);
-
-               el = &fe->id2.i_list;
-               /* If we have tree depth, then the fe update is
-                * trivial, and we want to switch el out for the
-                * bottom-most leaf in order to update it with the
-                * actual extent data below. */
-               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);
-                       status = -EIO;
-                       goto bail;
-               }
-               le32_add_cpu(&el->l_recs[next_free - 1].e_clusters,
-                            new_clusters);
-               /* (num_bhs - 1) to avoid the leaf */
-               for(i = 0; i < (num_bhs - 1); i++) {
-                       eb = (struct ocfs2_extent_block *) eb_bhs[i]->b_data;
-                       el = &eb->h_list;
-
-                       /* finally, make our actual change to the
-                        * intermediate extent blocks. */
-                       next_free = le16_to_cpu(el->l_next_free_rec);
-                       le32_add_cpu(&el->l_recs[next_free - 1].e_clusters,
-                                    new_clusters);
-
-                       status = ocfs2_journal_dirty(handle, eb_bhs[i]);
-                       if (status < 0)
-                               mlog_errno(status);
-               }
-               BUG_ON(i != (num_bhs - 1));
-               /* note that the leaf block wasn't touched in
-                * the loop above */
-               eb = (struct ocfs2_extent_block *) eb_bhs[num_bhs - 1]->b_data;
-               el = &eb->h_list;
-               BUG_ON(el->l_tree_depth);
-       }
-
-       /* yay, we can finally add the actual extent now! */
-       i = le16_to_cpu(el->l_next_free_rec) - 1;
-       if (le16_to_cpu(el->l_next_free_rec) &&
-           ocfs2_extent_contig(inode, &el->l_recs[i], start_blk)) {
-               le32_add_cpu(&el->l_recs[i].e_clusters, new_clusters);
-       } else if (le16_to_cpu(el->l_next_free_rec) &&
-                  (le32_to_cpu(el->l_recs[i].e_clusters) == 0)) {
-               /* having an empty extent at eof is legal. */
-               if (el->l_recs[i].e_cpos != fe->i_clusters) {
-                       ocfs2_error(inode->i_sb,
-                                   "Dinode %llu trailing extent is bad: "
-                                   "cpos (%u) != number of clusters (%u)",
-                                   (unsigned long long)OCFS2_I(inode)->ip_blkno,
-                                   le32_to_cpu(el->l_recs[i].e_cpos),
-                                   le32_to_cpu(fe->i_clusters));
-                       status = -EIO;
-                       goto bail;
-               }
-               el->l_recs[i].e_blkno = cpu_to_le64(start_blk);
-               el->l_recs[i].e_clusters = cpu_to_le32(new_clusters);
-       } else {
-               /* No contiguous record, or no empty record at eof, so
-                * we add a new one. */
-
-               BUG_ON(le16_to_cpu(el->l_next_free_rec) >=
-                      le16_to_cpu(el->l_count));
-               i = le16_to_cpu(el->l_next_free_rec);
-
-               el->l_recs[i].e_blkno = cpu_to_le64(start_blk);
-               el->l_recs[i].e_clusters = cpu_to_le32(new_clusters);
-               el->l_recs[i].e_cpos = fe->i_clusters;
-               le16_add_cpu(&el->l_next_free_rec, 1);
-       }
-
-       /*
-        * extent_map errors are not fatal, so they are ignored outside
-        * of flushing the thing.
-        */
-       status = ocfs2_extent_map_append(inode, &el->l_recs[i],
-                                        new_clusters);
-       if (status) {
-               mlog_errno(status);
-               ocfs2_extent_map_drop(inode, le32_to_cpu(fe->i_clusters));
-       }
-
-       status = ocfs2_journal_dirty(handle, fe_bh);
-       if (status < 0)
-               mlog_errno(status);
-       if (fe->id2.i_list.l_tree_depth) {
-               status = ocfs2_journal_dirty(handle, eb_bhs[num_bhs - 1]);
-               if (status < 0)
-                       mlog_errno(status);
-       }
-
-       status = 0;
-bail:
-       if (eb_bhs) {
-               for (i = 0; i < num_bhs; i++)
-                       if (eb_bhs[i])
-                               brelse(eb_bhs[i]);
-               kfree(eb_bhs);
-       }
-
-       mlog_exit(status);
-       return status;
-}
-
 /*
  * Should only be called when there is no space left in any of the
  * leaf nodes. What we want to do is find the lowest tree depth
@@ -807,53 +828,1548 @@ bail:
        return status;
 }
 
-/* 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,
-                       u64 start_blk,
-                       u32 new_clusters,
-                       struct ocfs2_alloc_context *meta_ac)
+/*
+ * This is only valid for leaf nodes, which are the only ones that can
+ * have empty extents anyway.
+ */
+static inline int ocfs2_is_empty_extent(struct ocfs2_extent_rec *rec)
 {
-       int status, i, shift;
-       struct buffer_head *last_eb_bh = NULL;
-       struct buffer_head *bh = NULL;
-       struct ocfs2_dinode *fe;
-       struct ocfs2_extent_block *eb;
-       struct ocfs2_extent_list  *el;
+       return !rec->e_leaf_clusters;
+}
 
-       mlog_entry_void();
+/*
+ * This function will discard the rightmost extent record.
+ */
+static void ocfs2_shift_records_right(struct ocfs2_extent_list *el)
+{
+       int next_free = le16_to_cpu(el->l_next_free_rec);
+       int count = le16_to_cpu(el->l_count);
+       unsigned int num_bytes;
 
-       mlog(0, "add %u clusters starting at block %llu to inode %llu\n",
-            new_clusters, (unsigned long long)start_blk,
-            (unsigned long long)OCFS2_I(inode)->ip_blkno);
+       BUG_ON(!next_free);
+       /* This will cause us to go off the end of our extent list. */
+       BUG_ON(next_free >= count);
 
-       fe = (struct ocfs2_dinode *) fe_bh->b_data;
-       el = &fe->id2.i_list;
+       num_bytes = sizeof(struct ocfs2_extent_rec) * next_free;
 
-       if (el->l_tree_depth) {
-               /* jump to end of tree */
-               status = ocfs2_read_block(osb, le64_to_cpu(fe->i_last_eb_blk),
-                                         &last_eb_bh, OCFS2_BH_CACHED, inode);
-               if (status < 0) {
-                       mlog_exit(status);
-                       goto bail;
-               }
-               eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
-               el = &eb->h_list;
-       }
+       memmove(&el->l_recs[1], &el->l_recs[0], num_bytes);
+}
 
-       /* Can we allocate without adding/shifting tree bits? */
-       i = le16_to_cpu(el->l_next_free_rec) - 1;
-       if (le16_to_cpu(el->l_next_free_rec) == 0
-           || (le16_to_cpu(el->l_next_free_rec) < le16_to_cpu(el->l_count))
-           || le32_to_cpu(el->l_recs[i].e_clusters) == 0
-           || ocfs2_extent_contig(inode, &el->l_recs[i], start_blk))
-               goto out_add;
+static void ocfs2_rotate_leaf(struct ocfs2_extent_list *el,
+                             struct ocfs2_extent_rec *insert_rec)
+{
+       int i, insert_index, next_free, has_empty, num_bytes;
+       u32 insert_cpos = le32_to_cpu(insert_rec->e_cpos);
+       struct ocfs2_extent_rec *rec;
 
-       mlog(0, "ocfs2_allocate_extent: couldn't do a simple add, traversing "
-            "tree now.\n");
+       next_free = le16_to_cpu(el->l_next_free_rec);
+       has_empty = ocfs2_is_empty_extent(&el->l_recs[0]);
+
+       BUG_ON(!next_free);
+
+       /* The tree code before us didn't allow enough room in the leaf. */
+       if (el->l_next_free_rec == el->l_count && !has_empty)
+               BUG();
+
+       /*
+        * The easiest way to approach this is to just remove the
+        * empty extent and temporarily decrement next_free.
+        */
+       if (has_empty) {
+               /*
+                * If next_free was 1 (only an empty extent), this
+                * loop won't execute, which is fine. We still want
+                * the decrement above to happen.
+                */
+               for(i = 0; i < (next_free - 1); i++)
+                       el->l_recs[i] = el->l_recs[i+1];
+
+               next_free--;
+       }
+
+       /*
+        * Figure out what the new record index should be.
+        */
+       for(i = 0; i < next_free; i++) {
+               rec = &el->l_recs[i];
+
+               if (insert_cpos < le32_to_cpu(rec->e_cpos))
+                       break;
+       }
+       insert_index = i;
+
+       mlog(0, "ins %u: index %d, has_empty %d, next_free %d, count %d\n",
+            insert_cpos, insert_index, has_empty, next_free, le16_to_cpu(el->l_count));
+
+       BUG_ON(insert_index < 0);
+       BUG_ON(insert_index >= le16_to_cpu(el->l_count));
+       BUG_ON(insert_index > next_free);
+
+       /*
+        * No need to memmove if we're just adding to the tail.
+        */
+       if (insert_index != next_free) {
+               BUG_ON(next_free >= le16_to_cpu(el->l_count));
+
+               num_bytes = next_free - insert_index;
+               num_bytes *= sizeof(struct ocfs2_extent_rec);
+               memmove(&el->l_recs[insert_index + 1],
+                       &el->l_recs[insert_index],
+                       num_bytes);
+       }
+
+       /*
+        * Either we had an empty extent, and need to re-increment or
+        * there was no empty extent on a non full rightmost leaf node,
+        * in which case we still need to increment.
+        */
+       next_free++;
+       el->l_next_free_rec = cpu_to_le16(next_free);
+       /*
+        * Make sure none of the math above just messed up our tree.
+        */
+       BUG_ON(le16_to_cpu(el->l_next_free_rec) > le16_to_cpu(el->l_count));
+
+       el->l_recs[insert_index] = *insert_rec;
+
+}
+
+/*
+ * Create an empty extent record .
+ *
+ * l_next_free_rec may be updated.
+ *
+ * If an empty extent already exists do nothing.
+ */
+static void ocfs2_create_empty_extent(struct ocfs2_extent_list *el)
+{
+       int next_free = le16_to_cpu(el->l_next_free_rec);
+
+       BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
+
+       if (next_free == 0)
+               goto set_and_inc;
+
+       if (ocfs2_is_empty_extent(&el->l_recs[0]))
+               return;
+
+       mlog_bug_on_msg(el->l_count == el->l_next_free_rec,
+                       "Asked to create an empty extent in a full list:\n"
+                       "count = %u, tree depth = %u",
+                       le16_to_cpu(el->l_count),
+                       le16_to_cpu(el->l_tree_depth));
+
+       ocfs2_shift_records_right(el);
+
+set_and_inc:
+       le16_add_cpu(&el->l_next_free_rec, 1);
+       memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
+}
+
+/*
+ * For a rotation which involves two leaf nodes, the "root node" is
+ * the lowest level tree node which contains a path to both leafs. This
+ * resulting set of information can be used to form a complete "subtree"
+ *
+ * This function is passed two full paths from the dinode down to a
+ * pair of adjacent leaves. It's task is to figure out which path
+ * index contains the subtree root - this can be the root index itself
+ * in a worst-case rotation.
+ *
+ * The array index of the subtree root is passed back.
+ */
+static int ocfs2_find_subtree_root(struct inode *inode,
+                                  struct ocfs2_path *left,
+                                  struct ocfs2_path *right)
+{
+       int i = 0;
+
+       /*
+        * Check that the caller passed in two paths from the same tree.
+        */
+       BUG_ON(path_root_bh(left) != path_root_bh(right));
+
+       do {
+               i++;
+
+               /*
+                * The caller didn't pass two adjacent paths.
+                */
+               mlog_bug_on_msg(i > left->p_tree_depth,
+                               "Inode %lu, left depth %u, right depth %u\n"
+                               "left leaf blk %llu, right leaf blk %llu\n",
+                               inode->i_ino, left->p_tree_depth,
+                               right->p_tree_depth,
+                               (unsigned long long)path_leaf_bh(left)->b_blocknr,
+                               (unsigned long long)path_leaf_bh(right)->b_blocknr);
+       } while (left->p_node[i].bh->b_blocknr ==
+                right->p_node[i].bh->b_blocknr);
+
+       return i - 1;
+}
+
+typedef void (path_insert_t)(void *, struct buffer_head *);
+
+/*
+ * Traverse a btree path in search of cpos, starting at root_el.
+ *
+ * This code can be called with a cpos larger than the tree, in which
+ * case it will return the rightmost path.
+ */
+static int __ocfs2_find_path(struct inode *inode,
+                            struct ocfs2_extent_list *root_el, u32 cpos,
+                            path_insert_t *func, void *data)
+{
+       int i, ret = 0;
+       u32 range;
+       u64 blkno;
+       struct buffer_head *bh = NULL;
+       struct ocfs2_extent_block *eb;
+       struct ocfs2_extent_list *el;
+       struct ocfs2_extent_rec *rec;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+
+       el = root_el;
+       while (el->l_tree_depth) {
+               if (le16_to_cpu(el->l_next_free_rec) == 0) {
+                       ocfs2_error(inode->i_sb,
+                                   "Inode %llu has empty extent list at "
+                                   "depth %u\n",
+                                   (unsigned long long)oi->ip_blkno,
+                                   le16_to_cpu(el->l_tree_depth));
+                       ret = -EROFS;
+                       goto out;
+
+               }
+
+               for(i = 0; i < le16_to_cpu(el->l_next_free_rec) - 1; i++) {
+                       rec = &el->l_recs[i];
+
+                       /*
+                        * In the case that cpos is off the allocation
+                        * tree, this should just wind up returning the
+                        * rightmost record.
+                        */
+                       range = le32_to_cpu(rec->e_cpos) +
+                               ocfs2_rec_clusters(el, rec);
+                       if (cpos >= le32_to_cpu(rec->e_cpos) && cpos < range)
+                           break;
+               }
+
+               blkno = le64_to_cpu(el->l_recs[i].e_blkno);
+               if (blkno == 0) {
+                       ocfs2_error(inode->i_sb,
+                                   "Inode %llu has bad blkno in extent list "
+                                   "at depth %u (index %d)\n",
+                                   (unsigned long long)oi->ip_blkno,
+                                   le16_to_cpu(el->l_tree_depth), i);
+                       ret = -EROFS;
+                       goto out;
+               }
+
+               brelse(bh);
+               bh = NULL;
+               ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), blkno,
+                                      &bh, OCFS2_BH_CACHED, inode);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               eb = (struct ocfs2_extent_block *) bh->b_data;
+               el = &eb->h_list;
+               if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
+                       OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
+                       ret = -EIO;
+                       goto out;
+               }
+
+               if (le16_to_cpu(el->l_next_free_rec) >
+                   le16_to_cpu(el->l_count)) {
+                       ocfs2_error(inode->i_sb,
+                                   "Inode %llu has bad count in extent list "
+                                   "at block %llu (next free=%u, count=%u)\n",
+                                   (unsigned long long)oi->ip_blkno,
+                                   (unsigned long long)bh->b_blocknr,
+                                   le16_to_cpu(el->l_next_free_rec),
+                                   le16_to_cpu(el->l_count));
+                       ret = -EROFS;
+                       goto out;
+               }
+
+               if (func)
+                       func(data, bh);
+       }
+
+out:
+       /*
+        * Catch any trailing bh that the loop didn't handle.
+        */
+       brelse(bh);
+
+       return ret;
+}
+
+/*
+ * Given an initialized path (that is, it has a valid root extent
+ * list), this function will traverse the btree in search of the path
+ * which would contain cpos.
+ *
+ * The path traveled is recorded in the path structure.
+ *
+ * Note that this will not do any comparisons on leaf node extent
+ * records, so it will work fine in the case that we just added a tree
+ * branch.
+ */
+struct find_path_data {
+       int index;
+       struct ocfs2_path *path;
+};
+static void find_path_ins(void *data, struct buffer_head *bh)
+{
+       struct find_path_data *fp = data;
+
+       get_bh(bh);
+       ocfs2_path_insert_eb(fp->path, fp->index, bh);
+       fp->index++;
+}
+static int ocfs2_find_path(struct inode *inode, struct ocfs2_path *path,
+                          u32 cpos)
+{
+       struct find_path_data data;
+
+       data.index = 1;
+       data.path = path;
+       return __ocfs2_find_path(inode, path_root_el(path), cpos,
+                                find_path_ins, &data);
+}
+
+static void find_leaf_ins(void *data, struct buffer_head *bh)
+{
+       struct ocfs2_extent_block *eb =(struct ocfs2_extent_block *)bh->b_data;
+       struct ocfs2_extent_list *el = &eb->h_list;
+       struct buffer_head **ret = data;
+
+       /* We want to retain only the leaf block. */
+       if (le16_to_cpu(el->l_tree_depth) == 0) {
+               get_bh(bh);
+               *ret = bh;
+       }
+}
+/*
+ * Find the leaf block in the tree which would contain cpos. No
+ * checking of the actual leaf is done.
+ *
+ * Some paths want to call this instead of allocating a path structure
+ * and calling ocfs2_find_path().
+ *
+ * This function doesn't handle non btree extent lists.
+ */
+int ocfs2_find_leaf(struct inode *inode, struct ocfs2_extent_list *root_el,
+                   u32 cpos, struct buffer_head **leaf_bh)
+{
+       int ret;
+       struct buffer_head *bh = NULL;
+
+       ret = __ocfs2_find_path(inode, root_el, cpos, find_leaf_ins, &bh);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       *leaf_bh = bh;
+out:
+       return ret;
+}
+
+/*
+ * Adjust the adjacent records (left_rec, right_rec) involved in a rotation.
+ *
+ * Basically, we've moved stuff around at the bottom of the tree and
+ * we need to fix up the extent records above the changes to reflect
+ * the new changes.
+ *
+ * left_rec: the record on the left.
+ * left_child_el: is the child list pointed to by left_rec
+ * right_rec: the record to the right of left_rec
+ * right_child_el: is the child list pointed to by right_rec
+ *
+ * By definition, this only works on interior nodes.
+ */
+static void ocfs2_adjust_adjacent_records(struct ocfs2_extent_rec *left_rec,
+                                 struct ocfs2_extent_list *left_child_el,
+                                 struct ocfs2_extent_rec *right_rec,
+                                 struct ocfs2_extent_list *right_child_el)
+{
+       u32 left_clusters, right_end;
+
+       /*
+        * Interior nodes never have holes. Their cpos is the cpos of
+        * the leftmost record in their child list. Their cluster
+        * count covers the full theoretical range of their child list
+        * - the range between their cpos and the cpos of the record
+        * immediately to their right.
+        */
+       left_clusters = le32_to_cpu(right_child_el->l_recs[0].e_cpos);
+       left_clusters -= le32_to_cpu(left_rec->e_cpos);
+       left_rec->e_int_clusters = cpu_to_le32(left_clusters);
+
+       /*
+        * Calculate the rightmost cluster count boundary before
+        * moving cpos - we will need to adjust clusters after
+        * updating e_cpos to keep the same highest cluster count.
+        */
+       right_end = le32_to_cpu(right_rec->e_cpos);
+       right_end += le32_to_cpu(right_rec->e_int_clusters);
+
+       right_rec->e_cpos = left_rec->e_cpos;
+       le32_add_cpu(&right_rec->e_cpos, left_clusters);
+
+       right_end -= le32_to_cpu(right_rec->e_cpos);
+       right_rec->e_int_clusters = cpu_to_le32(right_end);
+}
+
+/*
+ * Adjust the adjacent root node records involved in a
+ * rotation. left_el_blkno is passed in as a key so that we can easily
+ * find it's index in the root list.
+ */
+static void ocfs2_adjust_root_records(struct ocfs2_extent_list *root_el,
+                                     struct ocfs2_extent_list *left_el,
+                                     struct ocfs2_extent_list *right_el,
+                                     u64 left_el_blkno)
+{
+       int i;
+
+       BUG_ON(le16_to_cpu(root_el->l_tree_depth) <=
+              le16_to_cpu(left_el->l_tree_depth));
+
+       for(i = 0; i < le16_to_cpu(root_el->l_next_free_rec) - 1; i++) {
+               if (le64_to_cpu(root_el->l_recs[i].e_blkno) == left_el_blkno)
+                       break;
+       }
+
+       /*
+        * The path walking code should have never returned a root and
+        * two paths which are not adjacent.
+        */
+       BUG_ON(i >= (le16_to_cpu(root_el->l_next_free_rec) - 1));
+
+       ocfs2_adjust_adjacent_records(&root_el->l_recs[i], left_el,
+                                     &root_el->l_recs[i + 1], right_el);
+}
+
+/*
+ * We've changed a leaf block (in right_path) and need to reflect that
+ * change back up the subtree.
+ *
+ * This happens in multiple places:
+ *   - When we've moved an extent record from the left path leaf to the right
+ *     path leaf to make room for an empty extent in the left path leaf.
+ *   - When our insert into the right path leaf is at the leftmost edge
+ *     and requires an update of the path immediately to it's left. This
+ *     can occur at the end of some types of rotation and appending inserts.
+ */
+static void ocfs2_complete_edge_insert(struct inode *inode, handle_t *handle,
+                                      struct ocfs2_path *left_path,
+                                      struct ocfs2_path *right_path,
+                                      int subtree_index)
+{
+       int ret, i, idx;
+       struct ocfs2_extent_list *el, *left_el, *right_el;
+       struct ocfs2_extent_rec *left_rec, *right_rec;
+       struct buffer_head *root_bh = left_path->p_node[subtree_index].bh;
+
+       /*
+        * Update the counts and position values within all the
+        * interior nodes to reflect the leaf rotation we just did.
+        *
+        * The root node is handled below the loop.
+        *
+        * We begin the loop with right_el and left_el pointing to the
+        * leaf lists and work our way up.
+        *
+        * NOTE: within this loop, left_el and right_el always refer
+        * to the *child* lists.
+        */
+       left_el = path_leaf_el(left_path);
+       right_el = path_leaf_el(right_path);
+       for(i = left_path->p_tree_depth - 1; i > subtree_index; i--) {
+               mlog(0, "Adjust records at index %u\n", i);
+
+               /*
+                * One nice property of knowing that all of these
+                * nodes are below the root is that we only deal with
+                * the leftmost right node record and the rightmost
+                * left node record.
+                */
+               el = left_path->p_node[i].el;
+               idx = le16_to_cpu(left_el->l_next_free_rec) - 1;
+               left_rec = &el->l_recs[idx];
+
+               el = right_path->p_node[i].el;
+               right_rec = &el->l_recs[0];
+
+               ocfs2_adjust_adjacent_records(left_rec, left_el, right_rec,
+                                             right_el);
+
+               ret = ocfs2_journal_dirty(handle, left_path->p_node[i].bh);
+               if (ret)
+                       mlog_errno(ret);
+
+               ret = ocfs2_journal_dirty(handle, right_path->p_node[i].bh);
+               if (ret)
+                       mlog_errno(ret);
+
+               /*
+                * Setup our list pointers now so that the current
+                * parents become children in the next iteration.
+                */
+               left_el = left_path->p_node[i].el;
+               right_el = right_path->p_node[i].el;
+       }
+
+       /*
+        * At the root node, adjust the two adjacent records which
+        * begin our path to the leaves.
+        */
+
+       el = left_path->p_node[subtree_index].el;
+       left_el = left_path->p_node[subtree_index + 1].el;
+       right_el = right_path->p_node[subtree_index + 1].el;
+
+       ocfs2_adjust_root_records(el, left_el, right_el,
+                                 left_path->p_node[subtree_index + 1].bh->b_blocknr);
+
+       root_bh = left_path->p_node[subtree_index].bh;
+
+       ret = ocfs2_journal_dirty(handle, root_bh);
+       if (ret)
+               mlog_errno(ret);
+}
+
+static int ocfs2_rotate_subtree_right(struct inode *inode,
+                                     handle_t *handle,
+                                     struct ocfs2_path *left_path,
+                                     struct ocfs2_path *right_path,
+                                     int subtree_index)
+{
+       int ret, i;
+       struct buffer_head *right_leaf_bh;
+       struct buffer_head *left_leaf_bh = NULL;
+       struct buffer_head *root_bh;
+       struct ocfs2_extent_list *right_el, *left_el;
+       struct ocfs2_extent_rec move_rec;
+
+       left_leaf_bh = path_leaf_bh(left_path);
+       left_el = path_leaf_el(left_path);
+
+       if (left_el->l_next_free_rec != left_el->l_count) {
+               ocfs2_error(inode->i_sb,
+                           "Inode %llu has non-full interior leaf node %llu"
+                           "(next free = %u)",
+                           (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                           (unsigned long long)left_leaf_bh->b_blocknr,
+                           le16_to_cpu(left_el->l_next_free_rec));
+               return -EROFS;
+       }
+
+       /*
+        * This extent block may already have an empty record, so we
+        * return early if so.
+        */
+       if (ocfs2_is_empty_extent(&left_el->l_recs[0]))
+               return 0;
+
+       root_bh = left_path->p_node[subtree_index].bh;
+       BUG_ON(root_bh != right_path->p_node[subtree_index].bh);
+
+       ret = ocfs2_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;
+               }
+       }
+
+       right_leaf_bh = path_leaf_bh(right_path);
+       right_el = path_leaf_el(right_path);
+
+       /* This is a code error, not a disk corruption. */
+       mlog_bug_on_msg(!right_el->l_next_free_rec, "Inode %llu: Rotate fails "
+                       "because rightmost leaf block %llu is empty\n",
+                       (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                       (unsigned long long)right_leaf_bh->b_blocknr);
+
+       ocfs2_create_empty_extent(right_el);
+
+       ret = ocfs2_journal_dirty(handle, right_leaf_bh);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       /* Do the copy now. */
+       i = le16_to_cpu(left_el->l_next_free_rec) - 1;
+       move_rec = left_el->l_recs[i];
+       right_el->l_recs[0] = move_rec;
+
+       /*
+        * Clear out the record we just copied and shift everything
+        * over, leaving an empty extent in the left leaf.
+        *
+        * We temporarily subtract from next_free_rec so that the
+        * shift will lose the tail record (which is now defunct).
+        */
+       le16_add_cpu(&left_el->l_next_free_rec, -1);
+       ocfs2_shift_records_right(left_el);
+       memset(&left_el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
+       le16_add_cpu(&left_el->l_next_free_rec, 1);
+
+       ret = ocfs2_journal_dirty(handle, left_leaf_bh);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       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 left of the current one.
+ *
+ * Will return zero if the path passed in is already the leftmost path.
+ */
+static int ocfs2_find_cpos_for_left_leaf(struct super_block *sb,
+                                        struct ocfs2_path *path, u32 *cpos)
+{
+       int i, j, ret = 0;
+       u64 blkno;
+       struct ocfs2_extent_list *el;
+
+       BUG_ON(path->p_tree_depth == 0);
+
+       *cpos = 0;
+
+       blkno = path_leaf_bh(path)->b_blocknr;
+
+       /* Start at the tree node just above the leaf and work our way up. */
+       i = path->p_tree_depth - 1;
+       while (i >= 0) {
+               el = path->p_node[i].el;
+
+               /*
+                * Find the extent record just before the one in our
+                * path.
+                */
+               for(j = 0; j < le16_to_cpu(el->l_next_free_rec); j++) {
+                       if (le64_to_cpu(el->l_recs[j].e_blkno) == blkno) {
+                               if (j == 0) {
+                                       if (i == 0) {
+                                               /*
+                                                * We've determined that the
+                                                * path specified is already
+                                                * the leftmost one - return a
+                                                * cpos of zero.
+                                                */
+                                               goto out;
+                                       }
+                                       /*
+                                        * The leftmost record points to our
+                                        * leaf - we need to travel up the
+                                        * tree one level.
+                                        */
+                                       goto next_node;
+                               }
+
+                               *cpos = le32_to_cpu(el->l_recs[j - 1].e_cpos);
+                               *cpos = *cpos + ocfs2_rec_clusters(el,
+                                                          &el->l_recs[j - 1]);
+                               *cpos = *cpos - 1;
+                               goto out;
+                       }
+               }
+
+               /*
+                * If we got here, we never found a valid node where
+                * the tree indicated one should be.
+                */
+               ocfs2_error(sb,
+                           "Invalid extent tree at extent block %llu\n",
+                           (unsigned long long)blkno);
+               ret = -EROFS;
+               goto out;
+
+next_node:
+               blkno = path->p_node[i].bh->b_blocknr;
+               i--;
+       }
+
+out:
+       return ret;
+}
+
+static int ocfs2_extend_rotate_transaction(handle_t *handle, int subtree_depth,
+                                          struct ocfs2_path *path)
+{
+       int credits = (path->p_tree_depth - subtree_depth) * 2 + 1;
+
+       if (handle->h_buffer_credits < credits)
+               return ocfs2_extend_trans(handle, credits);
+
+       return 0;
+}
+
+/*
+ * Trap the case where we're inserting into the theoretical range past
+ * the _actual_ left leaf range. Otherwise, we'll rotate a record
+ * whose cpos is less than ours into the right leaf.
+ *
+ * It's only necessary to look at the rightmost record of the left
+ * leaf because the logic that calls us should ensure that the
+ * theoretical ranges in the path components above the leaves are
+ * correct.
+ */
+static int ocfs2_rotate_requires_path_adjustment(struct ocfs2_path *left_path,
+                                                u32 insert_cpos)
+{
+       struct ocfs2_extent_list *left_el;
+       struct ocfs2_extent_rec *rec;
+       int next_free;
+
+       left_el = path_leaf_el(left_path);
+       next_free = le16_to_cpu(left_el->l_next_free_rec);
+       rec = &left_el->l_recs[next_free - 1];
+
+       if (insert_cpos > le32_to_cpu(rec->e_cpos))
+               return 1;
+       return 0;
+}
+
+/*
+ * Rotate all the records in a btree right one record, starting at insert_cpos.
+ *
+ * The path to the rightmost leaf should be passed in.
+ *
+ * The array is assumed to be large enough to hold an entire path (tree depth).
+ *
+ * Upon succesful return from this function:
+ *
+ * - The 'right_path' array will contain a path to the leaf block
+ *   whose range contains e_cpos.
+ * - That leaf block will have a single empty extent in list index 0.
+ * - In the case that the rotation requires a post-insert update,
+ *   *ret_left_path will contain a valid path which can be passed to
+ *   ocfs2_insert_path().
+ */
+static int ocfs2_rotate_tree_right(struct inode *inode,
+                                  handle_t *handle,
+                                  u32 insert_cpos,
+                                  struct ocfs2_path *right_path,
+                                  struct ocfs2_path **ret_left_path)
+{
+       int ret, start;
+       u32 cpos;
+       struct ocfs2_path *left_path = NULL;
+
+       *ret_left_path = NULL;
+
+       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_cpos_for_left_leaf(inode->i_sb, right_path, &cpos);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       mlog(0, "Insert: %u, first left path cpos: %u\n", insert_cpos, cpos);
+
+       /*
+        * What we want to do here is:
+        *
+        * 1) Start with the rightmost path.
+        *
+        * 2) Determine a path to the leaf block directly to the left
+        *    of that leaf.
+        *
+        * 3) Determine the 'subtree root' - the lowest level tree node
+        *    which contains a path to both leaves.
+        *
+        * 4) Rotate the subtree.
+        *
+        * 5) Find the next subtree by considering the left path to be
+        *    the new right path.
+        *
+        * The check at the top of this while loop also accepts
+        * insert_cpos == cpos because cpos is only a _theoretical_
+        * value to get us the left path - insert_cpos might very well
+        * be filling that hole.
+        *
+        * Stop at a cpos of '0' because we either started at the
+        * leftmost branch (i.e., a tree with one branch and a
+        * rotation inside of it), or we've gone as far as we can in
+        * rotating subtrees.
+        */
+       while (cpos && insert_cpos <= cpos) {
+               mlog(0, "Rotating a tree: ins. cpos: %u, left path cpos: %u\n",
+                    insert_cpos, cpos);
+
+               ret = ocfs2_find_path(inode, left_path, cpos);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               mlog_bug_on_msg(path_leaf_bh(left_path) ==
+                               path_leaf_bh(right_path),
+                               "Inode %lu: error during insert of %u "
+                               "(left path cpos %u) results in two identical "
+                               "paths ending at %llu\n",
+                               inode->i_ino, insert_cpos, cpos,
+                               (unsigned long long)
+                               path_leaf_bh(left_path)->b_blocknr);
+
+               if (ocfs2_rotate_requires_path_adjustment(left_path,
+                                                         insert_cpos)) {
+                       mlog(0, "Path adjustment required\n");
+
+                       /*
+                        * We've rotated the tree as much as we
+                        * should. The rest is up to
+                        * ocfs2_insert_path() to complete, after the
+                        * record insertion. We indicate this
+                        * situation by returning the left path.
+                        *
+                        * The reason we don't adjust the records here
+                        * before the record insert is that an error
+                        * later might break the rule where a parent
+                        * record e_cpos will reflect the actual
+                        * e_cpos of the 1st nonempty record of the
+                        * child list.
+                        */
+                       *ret_left_path = left_path;
+                       goto out_ret_path;
+               }
+
+               start = ocfs2_find_subtree_root(inode, left_path, right_path);
+
+               mlog(0, "Subtree root at index %d (blk %llu, depth %d)\n",
+                    start,
+                    (unsigned long long) right_path->p_node[start].bh->b_blocknr,
+                    right_path->p_tree_depth);
+
+               ret = ocfs2_extend_rotate_transaction(handle, start,
+                                                     right_path);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               ret = ocfs2_rotate_subtree_right(inode, handle, left_path,
+                                                right_path, start);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               /*
+                * There is no need to re-read the next right path
+                * as we know that it'll be our current left
+                * path. Optimize by copying values instead.
+                */
+               ocfs2_mv_path(right_path, left_path);
+
+               ret = ocfs2_find_cpos_for_left_leaf(inode->i_sb, right_path,
+                                                   &cpos);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+       }
+
+out:
+       ocfs2_free_path(left_path);
+
+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)
+{
+       int i = insert->ins_contig_index;
+       unsigned int range;
+       struct ocfs2_extent_rec *rec;
+
+       BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
+
+       /*
+        * 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;
+       }
+
+       /*
+        * 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 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, i, next_free;
+       struct buffer_head *bh;
+       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;
+       }
+
+       el = path_root_el(right_path);
+       bh = path_root_bh(right_path);
+       i = 0;
+       while (1) {
+               struct ocfs2_extent_rec *rec;
+
+               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;
+                       goto out;
+               }
+
+               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);
+
+               /* Don't touch the leaf node */
+               if (++i >= right_path->p_tree_depth)
+                       break;
+
+               bh = right_path->p_node[i].bh;
+               el = right_path->p_node[i].el;
+       }
+
+       *ret_left_path = left_path;
+       ret = 0;
+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.
+ *
+ * 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);
+       struct ocfs2_extent_list *el;
+
+       /*
+        * 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;
+               }
+       }
+
+       el = path_leaf_el(right_path);
+
+       ocfs2_insert_at_leaf(insert_rec, el, 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,
+                                             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:
+       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 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,
+                                   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 = &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;
+       }
+
+       /*
+        * 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 (!insert->ins_tree_depth) {
+               ocfs2_figure_contig_type(inode, insert, el, insert_rec);
+               ocfs2_figure_appending_type(insert, el, insert_rec);
+               return 0;
+       }
+
+       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,
+                       struct ocfs2_alloc_context *meta_ac)
+{
+       int status, shift;
+       struct buffer_head *last_eb_bh = NULL;
+       struct buffer_head *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);
+
+       status = ocfs2_figure_insert_type(inode, fe_bh, &last_eb_bh, &rec,
+                                         &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,
+            insert.ins_free_records, insert.ins_tree_depth);
+
+       /*
+        * Avoid growing the tree unless we're out of records and the
+        * insert type requres one.
+        */
+       if (insert.ins_contig != CONTIG_NONE || insert.ins_free_records)
+               goto out_add;
 
        shift = ocfs2_find_branch_target(osb, inode, fe_bh, &bh);
        if (shift < 0) {
@@ -866,13 +2382,9 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
         * and didn't find room for any more extents - we need to add
         * another tree level */
        if (shift) {
-               /* if we hit a leaf, we'd better be empty :) */
-               BUG_ON(le16_to_cpu(el->l_next_free_rec) !=
-                      le16_to_cpu(el->l_count));
                BUG_ON(bh);
-               mlog(0, "ocfs2_allocate_extent: need to shift tree depth "
-                    "(current = %u)\n",
-                    le16_to_cpu(fe->id2.i_list.l_tree_depth));
+               mlog(0, "need to shift tree depth "
+                    "(current = %d)\n", insert.ins_tree_depth);
 
                /* ocfs2_shift_tree_depth will return us a buffer with
                 * the new extent block (so we can pass that to
@@ -883,15 +2395,16 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
                        mlog_errno(status);
                        goto bail;
                }
+               insert.ins_tree_depth++;
                /* Special case: we have room now if we shifted from
                 * tree_depth 0 */
-               if (fe->id2.i_list.l_tree_depth == cpu_to_le16(1))
+               if (insert.ins_tree_depth == 1)
                        goto out_add;
        }
 
        /* call ocfs2_add_branch to add the final part of the tree with
         * the new data. */
-       mlog(0, "ocfs2_allocate_extent: add branch. bh = %p\n", bh);
+       mlog(0, "add branch. bh = %p\n", bh);
        status = ocfs2_add_branch(osb, handle, inode, fe_bh, bh, last_eb_bh,
                                  meta_ac);
        if (status < 0) {
@@ -900,11 +2413,12 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
        }
 
 out_add:
-       /* Finally, we can add clusters. */
-       status = ocfs2_do_insert_extent(osb, handle, inode, fe_bh,
-                                       start_blk, new_clusters);
+       /* 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 (bh)
@@ -1355,7 +2869,7 @@ int ocfs2_complete_truncate_log_recovery(struct ocfs2_super *osb,
        tl = &tl_copy->id2.i_dealloc;
        num_recs = le16_to_cpu(tl->tl_used);
        mlog(0, "cleanup %u records from %llu\n", num_recs,
-            (unsigned long long)tl_copy->i_blkno);
+            (unsigned long long)le64_to_cpu(tl_copy->i_blkno));
 
        mutex_lock(&tl_inode->i_mutex);
        for(i = 0; i < num_recs; i++) {
@@ -1447,168 +2961,389 @@ int ocfs2_truncate_log_init(struct ocfs2_super *osb)
  * block will be deleted, and if it will, what the new last extent
  * block will be so we can update his h_next_leaf_blk field, as well
  * as the dinodes i_last_eb_blk */
-static int ocfs2_find_new_last_ext_blk(struct ocfs2_super *osb,
-                                      struct inode *inode,
-                                      struct ocfs2_dinode *fe,
-                                      u32 new_i_clusters,
-                                      struct buffer_head *old_last_eb,
+static int ocfs2_find_new_last_ext_blk(struct inode *inode,
+                                      unsigned int clusters_to_del,
+                                      struct ocfs2_path *path,
                                       struct buffer_head **new_last_eb)
 {
-       int i, status = 0;
-       u64 block = 0;
+       int next_free, ret = 0;
+       u32 cpos;
+       struct ocfs2_extent_rec *rec;
        struct ocfs2_extent_block *eb;
        struct ocfs2_extent_list *el;
        struct buffer_head *bh = NULL;
 
        *new_last_eb = NULL;
 
-       if (!OCFS2_IS_VALID_DINODE(fe)) {
-               OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, fe);
-               status = -EIO;
-               goto bail;
-       }
-
        /* we have no tree, so of course, no last_eb. */
-       if (!fe->id2.i_list.l_tree_depth)
-               goto bail;
+       if (!path->p_tree_depth)
+               goto out;
 
        /* trunc to zero special case - this makes tree_depth = 0
         * regardless of what it is.  */
-       if (!new_i_clusters)
-               goto bail;
+       if (OCFS2_I(inode)->ip_clusters == clusters_to_del)
+               goto out;
 
-       eb = (struct ocfs2_extent_block *) old_last_eb->b_data;
-       el = &(eb->h_list);
+       el = path_leaf_el(path);
        BUG_ON(!el->l_next_free_rec);
 
-       /* Make sure that this guy will actually be empty after we
-        * clear away the data. */
-       if (le32_to_cpu(el->l_recs[0].e_cpos) < new_i_clusters)
-               goto bail;
+       /*
+        * Make sure that this extent list will actually be empty
+        * after we clear away the data. We can shortcut out if
+        * there's more than one non-empty extent in the
+        * list. Otherwise, a check of the remaining extent is
+        * necessary.
+        */
+       next_free = le16_to_cpu(el->l_next_free_rec);
+       rec = NULL;
+       if (ocfs2_is_empty_extent(&el->l_recs[0])) {
+               if (next_free > 2)
+                       goto out;
 
-       /* Ok, at this point, we know that last_eb will definitely
-        * change, so lets traverse the tree and find the second to
-        * last extent block. */
-       el = &(fe->id2.i_list);
-       /* go down the tree, */
-       do {
-               for(i = (le16_to_cpu(el->l_next_free_rec) - 1); i >= 0; i--) {
-                       if (le32_to_cpu(el->l_recs[i].e_cpos) <
-                           new_i_clusters) {
-                               block = le64_to_cpu(el->l_recs[i].e_blkno);
-                               break;
+               /* We may have a valid extent in index 1, check it. */
+               if (next_free == 2)
+                       rec = &el->l_recs[1];
+
+               /*
+                * Fall through - no more nonempty extents, so we want
+                * to delete this leaf.
+                */
+       } else {
+               if (next_free > 1)
+                       goto out;
+
+               rec = &el->l_recs[0];
+       }
+
+       if (rec) {
+               /*
+                * Check it we'll only be trimming off the end of this
+                * cluster.
+                */
+               if (le16_to_cpu(rec->e_leaf_clusters) > clusters_to_del)
+                       goto out;
+       }
+
+       ret = ocfs2_find_cpos_for_left_leaf(inode->i_sb, path, &cpos);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       ret = ocfs2_find_leaf(inode, path_root_el(path), cpos, &bh);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       eb = (struct ocfs2_extent_block *) bh->b_data;
+       el = &eb->h_list;
+       if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
+               OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
+               ret = -EROFS;
+               goto out;
+       }
+
+       *new_last_eb = bh;
+       get_bh(*new_last_eb);
+       mlog(0, "returning block %llu, (cpos: %u)\n",
+            (unsigned long long)le64_to_cpu(eb->h_blkno), cpos);
+out:
+       brelse(bh);
+
+       return ret;
+}
+
+/*
+ * Trim some clusters off the rightmost edge of a tree. Only called
+ * during truncate.
+ *
+ * The caller needs to:
+ *   - start journaling of each path component.
+ *   - compute and fully set up any new last ext block
+ */
+static int ocfs2_trim_tree(struct inode *inode, struct ocfs2_path *path,
+                          handle_t *handle, struct ocfs2_truncate_context *tc,
+                          u32 clusters_to_del, u64 *delete_start)
+{
+       int ret, i, index = path->p_tree_depth;
+       u32 new_edge = 0;
+       u64 deleted_eb = 0;
+       struct buffer_head *bh;
+       struct ocfs2_extent_list *el;
+       struct ocfs2_extent_rec *rec;
+
+       *delete_start = 0;
+
+       while (index >= 0) {
+               bh = path->p_node[index].bh;
+               el = path->p_node[index].el;
+
+               mlog(0, "traveling tree (index = %d, block = %llu)\n",
+                    index,  (unsigned long long)bh->b_blocknr);
+
+               BUG_ON(le16_to_cpu(el->l_next_free_rec) == 0);
+
+               if (index !=
+                   (path->p_tree_depth - le16_to_cpu(el->l_tree_depth))) {
+                       ocfs2_error(inode->i_sb,
+                                   "Inode %lu has invalid ext. block %llu",
+                                   inode->i_ino,
+                                   (unsigned long long)bh->b_blocknr);
+                       ret = -EROFS;
+                       goto out;
+               }
+
+find_tail_record:
+               i = le16_to_cpu(el->l_next_free_rec) - 1;
+               rec = &el->l_recs[i];
+
+               mlog(0, "Extent list before: record %d: (%u, %u, %llu), "
+                    "next = %u\n", i, le32_to_cpu(rec->e_cpos),
+                    ocfs2_rec_clusters(el, rec),
+                    (unsigned long long)le64_to_cpu(rec->e_blkno),
+                    le16_to_cpu(el->l_next_free_rec));
+
+               BUG_ON(ocfs2_rec_clusters(el, rec) < clusters_to_del);
+
+               if (le16_to_cpu(el->l_tree_depth) == 0) {
+                       /*
+                        * If the leaf block contains a single empty
+                        * extent and no records, we can just remove
+                        * the block.
+                        */
+                       if (i == 0 && ocfs2_is_empty_extent(rec)) {
+                               memset(rec, 0,
+                                      sizeof(struct ocfs2_extent_rec));
+                               el->l_next_free_rec = cpu_to_le16(0);
+
+                               goto delete;
+                       }
+
+                       /*
+                        * Remove any empty extents by shifting things
+                        * left. That should make life much easier on
+                        * the code below. This condition is rare
+                        * enough that we shouldn't see a performance
+                        * hit.
+                        */
+                       if (ocfs2_is_empty_extent(&el->l_recs[0])) {
+                               le16_add_cpu(&el->l_next_free_rec, -1);
+
+                               for(i = 0;
+                                   i < le16_to_cpu(el->l_next_free_rec); i++)
+                                       el->l_recs[i] = el->l_recs[i + 1];
+
+                               memset(&el->l_recs[i], 0,
+                                      sizeof(struct ocfs2_extent_rec));
+
+                               /*
+                                * We've modified our extent list. The
+                                * simplest way to handle this change
+                                * is to being the search from the
+                                * start again.
+                                */
+                               goto find_tail_record;
+                       }
+
+                       le16_add_cpu(&rec->e_leaf_clusters, -clusters_to_del);
+
+                       /*
+                        * We'll use "new_edge" on our way back up the
+                        * tree to know what our rightmost cpos is.
+                        */
+                       new_edge = le16_to_cpu(rec->e_leaf_clusters);
+                       new_edge += le32_to_cpu(rec->e_cpos);
+
+                       /*
+                        * The caller will use this to delete data blocks.
+                        */
+                       *delete_start = le64_to_cpu(rec->e_blkno)
+                               + ocfs2_clusters_to_blocks(inode->i_sb,
+                                       le16_to_cpu(rec->e_leaf_clusters));
+
+                       /*
+                        * If it's now empty, remove this record.
+                        */
+                       if (le16_to_cpu(rec->e_leaf_clusters) == 0) {
+                               memset(rec, 0,
+                                      sizeof(struct ocfs2_extent_rec));
+                               le16_add_cpu(&el->l_next_free_rec, -1);
+                       }
+               } else {
+                       if (le64_to_cpu(rec->e_blkno) == deleted_eb) {
+                               memset(rec, 0,
+                                      sizeof(struct ocfs2_extent_rec));
+                               le16_add_cpu(&el->l_next_free_rec, -1);
+
+                               goto delete;
                        }
+
+                       /* Can this actually happen? */
+                       if (le16_to_cpu(el->l_next_free_rec) == 0)
+                               goto delete;
+
+                       /*
+                        * We never actually deleted any clusters
+                        * because our leaf was empty. There's no
+                        * reason to adjust the rightmost edge then.
+                        */
+                       if (new_edge == 0)
+                               goto delete;
+
+                       rec->e_int_clusters = cpu_to_le32(new_edge);
+                       le32_add_cpu(&rec->e_int_clusters,
+                                    -le32_to_cpu(rec->e_cpos));
+
+                        /*
+                         * A deleted child record should have been
+                         * caught above.
+                         */
+                        BUG_ON(le32_to_cpu(rec->e_int_clusters) == 0);
                }
-               BUG_ON(i < 0);
 
-               if (bh) {
-                       brelse(bh);
-                       bh = NULL;
-               }
+delete:
+               ret = ocfs2_journal_dirty(handle, bh);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               mlog(0, "extent list container %llu, after: record %d: "
+                    "(%u, %u, %llu), next = %u.\n",
+                    (unsigned long long)bh->b_blocknr, i,
+                    le32_to_cpu(rec->e_cpos), ocfs2_rec_clusters(el, rec),
+                    (unsigned long long)le64_to_cpu(rec->e_blkno),
+                    le16_to_cpu(el->l_next_free_rec));
+
+               /*
+                * We must be careful to only attempt delete of an
+                * extent block (and not the root inode block).
+                */
+               if (index > 0 && le16_to_cpu(el->l_next_free_rec) == 0) {
+                       struct ocfs2_extent_block *eb =
+                               (struct ocfs2_extent_block *)bh->b_data;
+
+                       /*
+                        * Save this for use when processing the
+                        * parent block.
+                        */
+                       deleted_eb = le64_to_cpu(eb->h_blkno);
+
+                       mlog(0, "deleting this extent block.\n");
 
-               status = ocfs2_read_block(osb, block, &bh, OCFS2_BH_CACHED,
-                                        inode);
-               if (status < 0) {
-                       mlog_errno(status);
-                       goto bail;
-               }
-               eb = (struct ocfs2_extent_block *) bh->b_data;
-               el = &eb->h_list;
-               if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
-                       OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
-                       status = -EIO;
-                       goto bail;
+                       ocfs2_remove_from_cache(inode, bh);
+
+                       BUG_ON(ocfs2_rec_clusters(el, &el->l_recs[0]));
+                       BUG_ON(le32_to_cpu(el->l_recs[0].e_cpos));
+                       BUG_ON(le64_to_cpu(el->l_recs[0].e_blkno));
+
+                       if (le16_to_cpu(eb->h_suballoc_slot) == 0) {
+                               /*
+                                * This code only understands how to
+                                * lock the suballocator in slot 0,
+                                * which is fine because allocation is
+                                * only ever done out of that
+                                * suballocator too. A future version
+                                * might change that however, so avoid
+                                * a free if we don't know how to
+                                * handle it. This way an fs incompat
+                                * bit will not be necessary.
+                                */
+                               ret = ocfs2_free_extent_block(handle,
+                                                             tc->tc_ext_alloc_inode,
+                                                             tc->tc_ext_alloc_bh,
+                                                             eb);
+
+                               /* An error here is not fatal. */
+                               if (ret < 0)
+                                       mlog_errno(ret);
+                       }
+               } else {
+                       deleted_eb = 0;
                }
-       } while (el->l_tree_depth);
 
-       *new_last_eb = bh;
-       get_bh(*new_last_eb);
-       mlog(0, "returning block %llu\n",
-            (unsigned long long)le64_to_cpu(eb->h_blkno));
-bail:
-       if (bh)
-               brelse(bh);
+               index--;
+       }
 
-       return status;
+       ret = 0;
+out:
+       return ret;
 }
 
 static int ocfs2_do_truncate(struct ocfs2_super *osb,
                             unsigned int clusters_to_del,
                             struct inode *inode,
                             struct buffer_head *fe_bh,
-                            struct buffer_head *old_last_eb_bh,
                             handle_t *handle,
-                            struct ocfs2_truncate_context *tc)
+                            struct ocfs2_truncate_context *tc,
+                            struct ocfs2_path *path)
 {
-       int status, i, depth;
+       int status;
        struct ocfs2_dinode *fe;
-       struct ocfs2_extent_block *eb;
        struct ocfs2_extent_block *last_eb = NULL;
        struct ocfs2_extent_list *el;
-       struct buffer_head *eb_bh = NULL;
        struct buffer_head *last_eb_bh = NULL;
-       u64 next_eb = 0;
        u64 delete_blk = 0;
 
        fe = (struct ocfs2_dinode *) fe_bh->b_data;
 
-       status = ocfs2_find_new_last_ext_blk(osb,
-                                            inode,
-                                            fe,
-                                            le32_to_cpu(fe->i_clusters) -
-                                                       clusters_to_del,
-                                            old_last_eb_bh,
-                                            &last_eb_bh);
+       status = ocfs2_find_new_last_ext_blk(inode, clusters_to_del,
+                                            path, &last_eb_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }
-       if (last_eb_bh)
-               last_eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
 
-       status = ocfs2_journal_access(handle, inode, fe_bh,
-                                     OCFS2_JOURNAL_ACCESS_WRITE);
+       /*
+        * Each component will be touched, so we might as well journal
+        * here to avoid having to handle errors later.
+        */
+       status = ocfs2_journal_access_path(inode, handle, path);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }
+
+       if (last_eb_bh) {
+               status = ocfs2_journal_access(handle, inode, last_eb_bh,
+                                             OCFS2_JOURNAL_ACCESS_WRITE);
+               if (status < 0) {
+                       mlog_errno(status);
+                       goto bail;
+               }
+
+               last_eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
+       }
+
        el = &(fe->id2.i_list);
 
+       /*
+        * Lower levels depend on this never happening, but it's best
+        * to check it up here before changing the tree.
+        */
+       if (el->l_tree_depth && el->l_recs[0].e_int_clusters == 0) {
+               ocfs2_error(inode->i_sb,
+                           "Inode %lu has an empty extent record, depth %u\n",
+                           inode->i_ino, le16_to_cpu(el->l_tree_depth));
+               status = -EROFS;
+               goto bail;
+       }
+
        spin_lock(&OCFS2_I(inode)->ip_lock);
        OCFS2_I(inode)->ip_clusters = le32_to_cpu(fe->i_clusters) -
                                      clusters_to_del;
        spin_unlock(&OCFS2_I(inode)->ip_lock);
        le32_add_cpu(&fe->i_clusters, -clusters_to_del);
-       fe->i_mtime = cpu_to_le64(CURRENT_TIME.tv_sec);
-       fe->i_mtime_nsec = cpu_to_le32(CURRENT_TIME.tv_nsec);
-
-       i = le16_to_cpu(el->l_next_free_rec) - 1;
-
-       BUG_ON(le32_to_cpu(el->l_recs[i].e_clusters) < clusters_to_del);
-       le32_add_cpu(&el->l_recs[i].e_clusters, -clusters_to_del);
-       /* tree depth zero, we can just delete the clusters, otherwise
-        * we need to record the offset of the next level extent block
-        * as we may overwrite it. */
-       if (!el->l_tree_depth)
-               delete_blk = le64_to_cpu(el->l_recs[i].e_blkno)
-                       + ocfs2_clusters_to_blocks(osb->sb,
-                                       le32_to_cpu(el->l_recs[i].e_clusters));
-       else
-               next_eb = le64_to_cpu(el->l_recs[i].e_blkno);
 
-       if (!el->l_recs[i].e_clusters) {
-               /* if we deleted the whole extent record, then clear
-                * out the other fields and update the extent
-                * list. For depth > 0 trees, we've already recorded
-                * the extent block in 'next_eb' */
-               el->l_recs[i].e_cpos = 0;
-               el->l_recs[i].e_blkno = 0;
-               BUG_ON(!el->l_next_free_rec);
-               le16_add_cpu(&el->l_next_free_rec, -1);
+       status = ocfs2_trim_tree(inode, path, handle, tc,
+                                clusters_to_del, &delete_blk);
+       if (status) {
+               mlog_errno(status);
+               goto bail;
        }
 
-       depth = le16_to_cpu(el->l_tree_depth);
-       if (!fe->i_clusters) {
+       if (le32_to_cpu(fe->i_clusters) == 0) {
                /* trunc to zero is a special case. */
                el->l_tree_depth = 0;
                fe->i_last_eb_blk = 0;
@@ -1625,12 +3360,6 @@ static int ocfs2_do_truncate(struct ocfs2_super *osb,
                /* If there will be a new last extent block, then by
                 * definition, there cannot be any leaves to the right of
                 * him. */
-               status = ocfs2_journal_access(handle, inode, last_eb_bh,
-                                             OCFS2_JOURNAL_ACCESS_WRITE);
-               if (status < 0) {
-                       mlog_errno(status);
-                       goto bail;
-               }
                last_eb->h_next_leaf_blk = 0;
                status = ocfs2_journal_dirty(handle, last_eb_bh);
                if (status < 0) {
@@ -1639,123 +3368,247 @@ static int ocfs2_do_truncate(struct ocfs2_super *osb,
                }
        }
 
-       /* if our tree depth > 0, update all the tree blocks below us. */
-       while (depth) {
-               mlog(0, "traveling tree (depth = %d, next_eb = %llu)\n",
-                    depth,  (unsigned long long)next_eb);
-               status = ocfs2_read_block(osb, next_eb, &eb_bh,
-                                         OCFS2_BH_CACHED, inode);
+       if (delete_blk) {
+               status = ocfs2_truncate_log_append(osb, handle, delete_blk,
+                                                  clusters_to_del);
                if (status < 0) {
                        mlog_errno(status);
                        goto bail;
                }
-               eb = (struct ocfs2_extent_block *)eb_bh->b_data;
-               if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
-                       OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
-                       status = -EIO;
-                       goto bail;
+       }
+       status = 0;
+bail:
+
+       mlog_exit(status);
+       return status;
+}
+
+static int ocfs2_writeback_zero_func(handle_t *handle, struct buffer_head *bh)
+{
+       set_buffer_uptodate(bh);
+       mark_buffer_dirty(bh);
+       return 0;
+}
+
+static int ocfs2_ordered_zero_func(handle_t *handle, struct buffer_head *bh)
+{
+       set_buffer_uptodate(bh);
+       mark_buffer_dirty(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)
+{
+       int i, ret, partial = 0;
+       void *kaddr;
+       struct page *page;
+       unsigned int from, to = PAGE_CACHE_SIZE;
+       struct super_block *sb = inode->i_sb;
+
+       BUG_ON(!ocfs2_sparse_alloc(OCFS2_SB(sb)));
+
+       if (numpages == 0)
+               goto out;
+
+       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);
+       }
+
+       for(i = 0; i < numpages; i++) {
+               page = pages[i];
+
+               BUG_ON(from > PAGE_CACHE_SIZE);
+               BUG_ON(to > PAGE_CACHE_SIZE);
+
+               ret = ocfs2_map_page_blocks(page, &phys, inode, from, to, 0);
+               if (ret)
+                       mlog_errno(ret);
+
+               kaddr = kmap_atomic(page, KM_USER0);
+               memset(kaddr + from, 0, to - from);
+               kunmap_atomic(kaddr, KM_USER0);
+
+               /*
+                * Need to set the buffers we zero'd into uptodate
+                * here if they aren't - ocfs2_map_page_blocks()
+                * might've skipped some
+                */
+               if (ocfs2_should_order_data(inode)) {
+                       ret = walk_page_buffers(handle,
+                                               page_buffers(page),
+                                               from, to, &partial,
+                                               ocfs2_ordered_zero_func);
+                       if (ret < 0)
+                               mlog_errno(ret);
+               } else {
+                       ret = walk_page_buffers(handle, page_buffers(page),
+                                               from, to, &partial,
+                                               ocfs2_writeback_zero_func);
+                       if (ret < 0)
+                               mlog_errno(ret);
                }
-               el = &(eb->h_list);
 
-               status = ocfs2_journal_access(handle, inode, eb_bh,
-                                             OCFS2_JOURNAL_ACCESS_WRITE);
-               if (status < 0) {
-                       mlog_errno(status);
-                       goto bail;
+               if (!partial)
+                       SetPageUptodate(page);
+
+               flush_dcache_page(page);
+
+               /*
+                * Every page after the 1st one should be completely zero'd.
+                */
+               from = 0;
+       }
+out:
+       if (pages) {
+               for (i = 0; i < numpages; i++) {
+                       page = pages[i];
+                       unlock_page(page);
+                       mark_page_accessed(page);
+                       page_cache_release(page);
                }
+       }
+}
 
-               BUG_ON(le16_to_cpu(el->l_next_free_rec) == 0);
-               BUG_ON(depth != (le16_to_cpu(el->l_tree_depth) + 1));
+static int ocfs2_grab_eof_pages(struct inode *inode, loff_t isize, 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;
+
+       BUG_ON(!ocfs2_sparse_alloc(OCFS2_SB(sb)));
+
+       /* Cluster boundary, so we don't need to grab any pages. */
+       if ((isize & (csize - 1)) == 0)
+               goto out;
 
-               i = le16_to_cpu(el->l_next_free_rec) - 1;
+       ret = ocfs2_extent_map_get_blocks(inode, isize >> sb->s_blocksize_bits,
+                                         phys, NULL, &ext_flags);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
 
-               mlog(0, "extent block %llu, before: record %d: "
-                    "(%u, %u, %llu), next = %u\n",
-                    (unsigned long long)le64_to_cpu(eb->h_blkno), i,
-                    le32_to_cpu(el->l_recs[i].e_cpos),
-                    le32_to_cpu(el->l_recs[i].e_clusters),
-                    (unsigned long long)le64_to_cpu(el->l_recs[i].e_blkno),
-                    le16_to_cpu(el->l_next_free_rec));
+       /* Tail is a hole. */
+       if (*phys == 0)
+               goto out;
 
-               BUG_ON(le32_to_cpu(el->l_recs[i].e_clusters) < clusters_to_del);
-               le32_add_cpu(&el->l_recs[i].e_clusters, -clusters_to_del);
-
-               next_eb = le64_to_cpu(el->l_recs[i].e_blkno);
-               /* bottom-most block requires us to delete data.*/
-               if (!el->l_tree_depth)
-                       delete_blk = le64_to_cpu(el->l_recs[i].e_blkno)
-                               + ocfs2_clusters_to_blocks(osb->sb,
-                                       le32_to_cpu(el->l_recs[i].e_clusters));
-               if (!el->l_recs[i].e_clusters) {
-                       el->l_recs[i].e_cpos = 0;
-                       el->l_recs[i].e_blkno = 0;
-                       BUG_ON(!el->l_next_free_rec);
-                       le16_add_cpu(&el->l_next_free_rec, -1);
-               }
-               mlog(0, "extent block %llu, after: record %d: "
-                    "(%u, %u, %llu), next = %u\n",
-                    (unsigned long long)le64_to_cpu(eb->h_blkno), i,
-                    le32_to_cpu(el->l_recs[i].e_cpos),
-                    le32_to_cpu(el->l_recs[i].e_clusters),
-                    (unsigned long long)le64_to_cpu(el->l_recs[i].e_blkno),
-                    le16_to_cpu(el->l_next_free_rec));
+       /* Tail is marked as unwritten, we can count on write to zero
+        * in that case. */
+       if (ext_flags & OCFS2_EXT_UNWRITTEN)
+               goto out;
 
-               status = ocfs2_journal_dirty(handle, eb_bh);
-               if (status < 0) {
-                       mlog_errno(status);
-                       goto bail;
+       next_cluster_bytes = ocfs2_align_bytes_to_clusters(inode->i_sb, isize);
+       index = isize >> PAGE_CACHE_SHIFT;
+       do {
+               pages[numpages] = grab_cache_page(mapping, index);
+               if (!pages[numpages]) {
+                       ret = -ENOMEM;
+                       mlog_errno(ret);
+                       goto out;
                }
 
-               if (!el->l_next_free_rec) {
-                       mlog(0, "deleting this extent block.\n");
-
-                       ocfs2_remove_from_cache(inode, eb_bh);
+               numpages++;
+               index++;
+       } while (index < (next_cluster_bytes >> PAGE_CACHE_SHIFT));
 
-                       BUG_ON(el->l_recs[0].e_clusters);
-                       BUG_ON(el->l_recs[0].e_cpos);
-                       BUG_ON(el->l_recs[0].e_blkno);
-                       if (eb->h_suballoc_slot == 0) {
-                               /*
-                                * This code only understands how to
-                                * lock the suballocator in slot 0,
-                                * which is fine because allocation is
-                                * only ever done out of that
-                                * suballocator too. A future version
-                                * might change that however, so avoid
-                                * a free if we don't know how to
-                                * handle it. This way an fs incompat
-                                * bit will not be necessary.
-                                */
-                               status = ocfs2_free_extent_block(handle,
-                                                                tc->tc_ext_alloc_inode,
-                                                                tc->tc_ext_alloc_bh,
-                                                                eb);
-                               if (status < 0) {
-                                       mlog_errno(status);
-                                       goto bail;
+out:
+       if (ret != 0) {
+               if (pages) {
+                       for (i = 0; i < numpages; i++) {
+                               if (pages[i]) {
+                                       unlock_page(pages[i]);
+                                       page_cache_release(pages[i]);
                                }
                        }
                }
-               brelse(eb_bh);
-               eb_bh = NULL;
-               depth--;
+               numpages = 0;
        }
 
-       BUG_ON(!delete_blk);
-       status = ocfs2_truncate_log_append(osb, handle, delete_blk,
-                                          clusters_to_del);
-       if (status < 0) {
-               mlog_errno(status);
-               goto bail;
+       *num = numpages;
+
+       return ret;
+}
+
+/*
+ * Zero the area past i_size but still within an allocated
+ * cluster. This avoids exposing nonzero data on subsequent file
+ * extends.
+ *
+ * We need to call this before i_size is updated on the inode because
+ * otherwise block_write_full_page() will skip writeout of pages past
+ * i_size. The new_i_size parameter is passed for this reason.
+ */
+int ocfs2_zero_tail_for_truncate(struct inode *inode, handle_t *handle,
+                                u64 new_i_size)
+{
+       int ret, numpages;
+       loff_t endbyte;
+       struct page **pages = NULL;
+       u64 phys;
+
+       /*
+        * File systems which don't support sparse files zero on every
+        * extend.
+        */
+       if (!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
+               return 0;
+
+       pages = kcalloc(ocfs2_pages_per_cluster(inode->i_sb),
+                       sizeof(struct page *), GFP_NOFS);
+       if (pages == NULL) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto out;
        }
-       status = 0;
-bail:
-       if (!status)
-               ocfs2_extent_map_trunc(inode, le32_to_cpu(fe->i_clusters));
-       else
-               ocfs2_extent_map_drop(inode, 0);
-       mlog_exit(status);
-       return status;
+
+       ret = ocfs2_grab_eof_pages(inode, new_i_size, pages, &numpages, &phys);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       if (numpages == 0)
+               goto out;
+
+       ocfs2_zero_cluster_pages(inode, new_i_size, 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);
+       if (ret)
+               mlog_errno(ret);
+
+out:
+       if (pages)
+               kfree(pages);
+
+       return ret;
 }
 
 /*
@@ -1770,82 +3623,88 @@ int ocfs2_commit_truncate(struct ocfs2_super *osb,
                          struct ocfs2_truncate_context *tc)
 {
        int status, i, credits, tl_sem = 0;
-       u32 clusters_to_del, target_i_clusters;
-       u64 last_eb = 0;
-       struct ocfs2_dinode *fe;
-       struct ocfs2_extent_block *eb;
+       u32 clusters_to_del, new_highest_cpos, range;
        struct ocfs2_extent_list *el;
-       struct buffer_head *last_eb_bh;
        handle_t *handle = NULL;
        struct inode *tl_inode = osb->osb_tl_inode;
+       struct ocfs2_path *path = NULL;
 
        mlog_entry_void();
 
-       down_write(&OCFS2_I(inode)->ip_alloc_sem);
-
-       target_i_clusters = ocfs2_clusters_for_bytes(osb->sb,
+       new_highest_cpos = ocfs2_clusters_for_bytes(osb->sb,
                                                     i_size_read(inode));
 
-       last_eb_bh = tc->tc_last_eb_bh;
-       tc->tc_last_eb_bh = NULL;
+       path = ocfs2_new_inode_path(fe_bh);
+       if (!path) {
+               status = -ENOMEM;
+               mlog_errno(status);
+               goto bail;
+       }
 
-       fe = (struct ocfs2_dinode *) fe_bh->b_data;
+       ocfs2_extent_map_trunc(inode, new_highest_cpos);
 
-       if (fe->id2.i_list.l_tree_depth) {
-               eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
-               el = &eb->h_list;
-       } else
-               el = &fe->id2.i_list;
-       last_eb = le64_to_cpu(fe->i_last_eb_blk);
 start:
-       mlog(0, "ocfs2_commit_truncate: fe->i_clusters = %u, "
-            "last_eb = %llu, fe->i_last_eb_blk = %llu, "
-            "fe->id2.i_list.l_tree_depth = %u last_eb_bh = %p\n",
-            le32_to_cpu(fe->i_clusters), (unsigned long long)last_eb,
-            (unsigned long long)le64_to_cpu(fe->i_last_eb_blk),
-            le16_to_cpu(fe->id2.i_list.l_tree_depth), last_eb_bh);
-
-       if (last_eb != le64_to_cpu(fe->i_last_eb_blk)) {
-               mlog(0, "last_eb changed!\n");
-               BUG_ON(!fe->id2.i_list.l_tree_depth);
-               last_eb = le64_to_cpu(fe->i_last_eb_blk);
-               /* i_last_eb_blk may have changed, read it if
-                * necessary. We don't have to worry about the
-                * truncate to zero case here (where there becomes no
-                * last_eb) because we never loop back after our work
-                * is done. */
-               if (last_eb_bh) {
-                       brelse(last_eb_bh);
-                       last_eb_bh = NULL;
-               }
+       /*
+        * Check that we still have allocation to delete.
+        */
+       if (OCFS2_I(inode)->ip_clusters == 0) {
+               status = 0;
+               goto bail;
+       }
 
-               status = ocfs2_read_block(osb, last_eb,
-                                         &last_eb_bh, OCFS2_BH_CACHED,
-                                         inode);
-               if (status < 0) {
-                       mlog_errno(status);
-                       goto bail;
-               }
-               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);
-                       status = -EIO;
-                       goto bail;
-               }
-               el = &(eb->h_list);
+       /*
+        * Truncate always works against the rightmost tree branch.
+        */
+       status = ocfs2_find_path(inode, path, UINT_MAX);
+       if (status) {
+               mlog_errno(status);
+               goto bail;
+       }
+
+       mlog(0, "inode->ip_clusters = %u, tree_depth = %u\n",
+            OCFS2_I(inode)->ip_clusters, path->p_tree_depth);
+
+       /*
+        * By now, el will point to the extent list on the bottom most
+        * portion of this tree. Only the tail record is considered in
+        * each pass.
+        *
+        * We handle the following cases, in order:
+        * - empty extent: delete the remaining branch
+        * - remove the entire record
+        * - remove a partial record
+        * - no record needs to be removed (truncate has completed)
+        */
+       el = path_leaf_el(path);
+       if (le16_to_cpu(el->l_next_free_rec) == 0) {
+               ocfs2_error(inode->i_sb,
+                           "Inode %llu has empty extent block at %llu\n",
+                           (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                           (unsigned long long)path_leaf_bh(path)->b_blocknr);
+               status = -EROFS;
+               goto bail;
        }
 
-       /* by now, el will point to the extent list on the bottom most
-        * portion of this tree. */
        i = le16_to_cpu(el->l_next_free_rec) - 1;
-       if (le32_to_cpu(el->l_recs[i].e_cpos) >= target_i_clusters)
-               clusters_to_del = le32_to_cpu(el->l_recs[i].e_clusters);
-       else
-               clusters_to_del = (le32_to_cpu(el->l_recs[i].e_clusters) +
+       range = le32_to_cpu(el->l_recs[i].e_cpos) +
+               ocfs2_rec_clusters(el, &el->l_recs[i]);
+       if (i == 0 && ocfs2_is_empty_extent(&el->l_recs[i])) {
+               clusters_to_del = 0;
+       } else if (le32_to_cpu(el->l_recs[i].e_cpos) >= new_highest_cpos) {
+               clusters_to_del = ocfs2_rec_clusters(el, &el->l_recs[i]);
+       } else if (range > new_highest_cpos) {
+               clusters_to_del = (ocfs2_rec_clusters(el, &el->l_recs[i]) +
                                   le32_to_cpu(el->l_recs[i].e_cpos)) -
-                                 target_i_clusters;
+                                 new_highest_cpos;
+       } else {
+               status = 0;
+               goto bail;
+       }
 
-       mlog(0, "clusters_to_del = %u in this pass\n", clusters_to_del);
+       mlog(0, "clusters_to_del = %u in this pass, tail blk=%llu\n",
+            clusters_to_del, (unsigned long long)path_leaf_bh(path)->b_blocknr);
+
+       BUG_ON(clusters_to_del == 0);
 
        mutex_lock(&tl_inode->i_mutex);
        tl_sem = 1;
@@ -1861,7 +3720,8 @@ start:
        }
 
        credits = ocfs2_calc_tree_trunc_credits(osb->sb, clusters_to_del,
-                                               fe, el);
+                                               (struct ocfs2_dinode *)fe_bh->b_data,
+                                               el);
        handle = ocfs2_start_trans(osb, credits);
        if (IS_ERR(handle)) {
                status = PTR_ERR(handle);
@@ -1870,13 +3730,8 @@ start:
                goto bail;
        }
 
-       inode->i_ctime = inode->i_mtime = CURRENT_TIME;
-       status = ocfs2_mark_inode_dirty(handle, inode, fe_bh);
-       if (status < 0)
-               mlog_errno(status);
-
-       status = ocfs2_do_truncate(osb, clusters_to_del, inode, fe_bh,
-                                  last_eb_bh, handle, tc);
+       status = ocfs2_do_truncate(osb, clusters_to_del, inode, fe_bh, handle,
+                                  tc, path);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
@@ -1888,11 +3743,15 @@ start:
        ocfs2_commit_trans(osb, handle);
        handle = NULL;
 
-       BUG_ON(le32_to_cpu(fe->i_clusters) < target_i_clusters);
-       if (le32_to_cpu(fe->i_clusters) > target_i_clusters)
-               goto start;
+       ocfs2_reinit_path(path, 1);
+
+       /*
+        * The check above will catch the case where we've truncated
+        * away all allocation.
+        */
+       goto start;
+
 bail:
-       up_write(&OCFS2_I(inode)->ip_alloc_sem);
 
        ocfs2_schedule_truncate_log_flush(osb, 1);
 
@@ -1902,8 +3761,7 @@ bail:
        if (handle)
                ocfs2_commit_trans(osb, handle);
 
-       if (last_eb_bh)
-               brelse(last_eb_bh);
+       ocfs2_free_path(path);
 
        /* This will drop the ext_alloc cluster lock for us */
        ocfs2_free_truncate_context(tc);
@@ -1912,7 +3770,6 @@ bail:
        return status;
 }
 
-
 /*
  * Expects the inode to already be locked. This will figure out which
  * inodes need to be locked and will put them on the returned truncate
@@ -1923,7 +3780,7 @@ int ocfs2_prepare_truncate(struct ocfs2_super *osb,
                           struct buffer_head *fe_bh,
                           struct ocfs2_truncate_context **tc)
 {
-       int status, metadata_delete;
+       int status, metadata_delete, i;
        unsigned int new_i_clusters;
        struct ocfs2_dinode *fe;
        struct ocfs2_extent_block *eb;
@@ -1941,25 +3798,10 @@ int ocfs2_prepare_truncate(struct ocfs2_super *osb,
        fe = (struct ocfs2_dinode *) fe_bh->b_data;
 
        mlog(0, "fe->i_clusters = %u, new_i_clusters = %u, fe->i_size ="
-            "%llu\n", fe->i_clusters, new_i_clusters,
-            (unsigned long long)fe->i_size);
-
-       if (le32_to_cpu(fe->i_clusters) <= new_i_clusters) {
-               ocfs2_error(inode->i_sb, "Dinode %llu has cluster count "
-                           "%u and size %llu whereas struct inode has "
-                           "cluster count %u and size %llu which caused an "
-                           "invalid truncate to %u clusters.",
-                           (unsigned long long)le64_to_cpu(fe->i_blkno),
-                           le32_to_cpu(fe->i_clusters),
-                           (unsigned long long)le64_to_cpu(fe->i_size),
-                           OCFS2_I(inode)->ip_clusters, i_size_read(inode),
-                           new_i_clusters);
-               mlog_meta_lvb(ML_ERROR, &OCFS2_I(inode)->ip_meta_lockres);
-               status = -EIO;
-               goto bail;
-       }
+            "%llu\n", le32_to_cpu(fe->i_clusters), new_i_clusters,
+            (unsigned long long)le64_to_cpu(fe->i_size));
 
-       *tc = kcalloc(1, sizeof(struct ocfs2_truncate_context), GFP_KERNEL);
+       *tc = kzalloc(sizeof(struct ocfs2_truncate_context), GFP_KERNEL);
        if (!(*tc)) {
                status = -ENOMEM;
                mlog_errno(status);
@@ -1986,7 +3828,15 @@ int ocfs2_prepare_truncate(struct ocfs2_super *osb,
                        goto bail;
                }
                el = &(eb->h_list);
-               if (le32_to_cpu(el->l_recs[0].e_cpos) >= new_i_clusters)
+
+               i = 0;
+               if (ocfs2_is_empty_extent(&el->l_recs[0]))
+                       i = 1;
+               /*
+                * XXX: Should we check that next_free_rec contains
+                * the extent?
+                */
+               if (le32_to_cpu(el->l_recs[i].e_cpos) >= new_i_clusters)
                        metadata_delete = 1;
        }