nfsd: move most of nfsfh.h to fs/nfsd
[safe/jmp/linux-2.6] / fs / ocfs2 / extent_map.c
index b6ba292..843db64 100644 (file)
@@ -3,8 +3,7 @@
  *
  * extent_map.c
  *
- * In-memory extent map for OCFS2.  Man, this code was prettier in
- * the library.
+ * Block/Cluster mapping functions
  *
  * Copyright (C) 2004 Oracle.  All rights reserved.
  *
 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/types.h>
-#include <linux/slab.h>
-#include <linux/rbtree.h>
+#include <linux/fiemap.h>
 
 #define MLOG_MASK_PREFIX ML_EXTENT_MAP
 #include <cluster/masklog.h>
 
 #include "ocfs2.h"
 
+#include "alloc.h"
+#include "dlmglue.h"
 #include "extent_map.h"
 #include "inode.h"
 #include "super.h"
 
 #include "buffer_head_io.h"
 
-
 /*
- * SUCK SUCK SUCK
- * Our headers are so bad that struct ocfs2_extent_map is in ocfs.h
+ * The extent caching implementation is intentionally trivial.
+ *
+ * We only cache a small number of extents stored directly on the
+ * inode, so linear order operations are acceptable. If we ever want
+ * to increase the size of the extent map, then these algorithms must
+ * get smarter.
  */
 
-struct ocfs2_extent_map_entry {
-       struct rb_node e_node;
-       int e_tree_depth;
-       struct ocfs2_extent_rec e_rec;
-};
-
-struct ocfs2_em_insert_context {
-       int need_left;
-       int need_right;
-       struct ocfs2_extent_map_entry *new_ent;
-       struct ocfs2_extent_map_entry *old_ent;
-       struct ocfs2_extent_map_entry *left_ent;
-       struct ocfs2_extent_map_entry *right_ent;
-};
-
-static kmem_cache_t *ocfs2_em_ent_cachep = NULL;
-
-
-static struct ocfs2_extent_map_entry *
-ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
-                       u32 cpos, u32 clusters,
-                       struct rb_node ***ret_p,
-                       struct rb_node **ret_parent);
-static int ocfs2_extent_map_insert(struct inode *inode,
-                                  struct ocfs2_extent_rec *rec,
-                                  int tree_depth);
-static int ocfs2_extent_map_insert_entry(struct ocfs2_extent_map *em,
-                                        struct ocfs2_extent_map_entry *ent);
-static int ocfs2_extent_map_find_leaf(struct inode *inode,
-                                     u32 cpos, u32 clusters,
-                                     struct ocfs2_extent_list *el);
-static int ocfs2_extent_map_lookup_read(struct inode *inode,
-                                       u32 cpos, u32 clusters,
-                                       struct ocfs2_extent_map_entry **ret_ent);
-static int ocfs2_extent_map_try_insert(struct inode *inode,
-                                      struct ocfs2_extent_rec *rec,
-                                      int tree_depth,
-                                      struct ocfs2_em_insert_context *ctxt);
-
-/* returns 1 only if the rec contains all the given clusters -- that is that
- * rec's cpos is <= the cluster cpos and that the rec endpoint (cpos +
- * clusters) is >= the argument's endpoint */
-static int ocfs2_extent_rec_contains_clusters(struct ocfs2_extent_rec *rec,
-                                             u32 cpos, u32 clusters)
+void ocfs2_extent_map_init(struct inode *inode)
 {
-       if (le32_to_cpu(rec->e_cpos) > cpos)
-               return 0;
-       if (cpos + clusters > le32_to_cpu(rec->e_cpos) + 
-                             le32_to_cpu(rec->e_clusters))
-               return 0;
-       return 1;
-}
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
 
-
-/*
- * Find an entry in the tree that intersects the region passed in.
- * Note that this will find straddled intervals, it is up to the
- * callers to enforce any boundary conditions.
- *
- * Callers must hold ip_lock.  This lookup is not guaranteed to return
- * a tree_depth 0 match, and as such can race inserts if the lock
- * were not held.
- *
- * The rb_node garbage lets insertion share the search.  Trivial
- * callers pass NULL.
- */
-static struct ocfs2_extent_map_entry *
-ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
-                       u32 cpos, u32 clusters,
-                       struct rb_node ***ret_p,
-                       struct rb_node **ret_parent)
-{
-       struct rb_node **p = &em->em_extents.rb_node;
-       struct rb_node *parent = NULL;
-       struct ocfs2_extent_map_entry *ent = NULL;
-
-       while (*p)
-       {
-               parent = *p;
-               ent = rb_entry(parent, struct ocfs2_extent_map_entry,
-                              e_node);
-               if ((cpos + clusters) <= le32_to_cpu(ent->e_rec.e_cpos)) {
-                       p = &(*p)->rb_left;
-                       ent = NULL;
-               } else if (cpos >= (le32_to_cpu(ent->e_rec.e_cpos) +
-                                   le32_to_cpu(ent->e_rec.e_clusters))) {
-                       p = &(*p)->rb_right;
-                       ent = NULL;
-               } else
-                       break;
-       }
-
-       if (ret_p != NULL)
-               *ret_p = p;
-       if (ret_parent != NULL)
-               *ret_parent = parent;
-       return ent;
+       oi->ip_extent_map.em_num_items = 0;
+       INIT_LIST_HEAD(&oi->ip_extent_map.em_list);
 }
 
-/*
- * Find the leaf containing the interval we want.  While we're on our
- * way down the tree, fill in every record we see at any depth, because
- * we might want it later.
- *
- * Note that this code is run without ip_lock.  That's because it
- * sleeps while reading.  If someone is also filling the extent list at
- * the same time we are, we might have to restart.
- */
-static int ocfs2_extent_map_find_leaf(struct inode *inode,
-                                     u32 cpos, u32 clusters,
-                                     struct ocfs2_extent_list *el)
+static void __ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
+                                     unsigned int cpos,
+                                     struct ocfs2_extent_map_item **ret_emi)
 {
-       int i, ret;
-       struct buffer_head *eb_bh = NULL;
-       u64 blkno;
-       u32 rec_end;
-       struct ocfs2_extent_block *eb;
-       struct ocfs2_extent_rec *rec;
-
-       /*
-        * The bh data containing the el cannot change here, because
-        * we hold alloc_sem.  So we can do this without other
-        * locks.
-        */
-       while (el->l_tree_depth)
-       {
-               blkno = 0;
-               for (i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
-                       rec = &el->l_recs[i];
-                       rec_end = (le32_to_cpu(rec->e_cpos) +
-                                  le32_to_cpu(rec->e_clusters));
-
-                       ret = -EBADR;
-                       if (rec_end > OCFS2_I(inode)->ip_clusters) {
-                               mlog_errno(ret);
-                               goto out_free;
-                       }
+       unsigned int range;
+       struct ocfs2_extent_map_item *emi;
 
-                       if (rec_end <= cpos) {
-                               ret = ocfs2_extent_map_insert(inode, rec,
-                                               le16_to_cpu(el->l_tree_depth));
-                               if (ret && (ret != -EEXIST)) {
-                                       mlog_errno(ret);
-                                       goto out_free;
-                               }
-                               continue;
-                       }
-                       if ((cpos + clusters) <= le32_to_cpu(rec->e_cpos)) {
-                               ret = ocfs2_extent_map_insert(inode, rec,
-                                               le16_to_cpu(el->l_tree_depth));
-                               if (ret && (ret != -EEXIST)) {
-                                       mlog_errno(ret);
-                                       goto out_free;
-                               }
-                               continue;
-                       }
+       *ret_emi = NULL;
 
-                       /*
-                        * We've found a record that matches our
-                        * interval.  We don't insert it because we're
-                        * about to traverse it.
-                        */
-
-                       /* Check to see if we're stradling */
-                       ret = -ESRCH;
-                       if (!ocfs2_extent_rec_contains_clusters(rec,
-                                                               cpos,
-                                                               clusters)) {
-                               mlog_errno(ret);
-                               goto out_free;
-                       }
-
-                       /*
-                        * If we've already found a record, the el has
-                        * two records covering the same interval.
-                        * EEEK!
-                        */
-                       ret = -EBADR;
-                       if (blkno) {
-                               mlog_errno(ret);
-                               goto out_free;
-                       }
-
-                       blkno = le64_to_cpu(rec->e_blkno);
-               }
+       list_for_each_entry(emi, &em->em_list, ei_list) {
+               range = emi->ei_cpos + emi->ei_clusters;
 
-               /*
-                * We don't support holes, and we're still up
-                * in the branches, so we'd better have found someone
-                */
-               ret = -EBADR;
-               if (!blkno) {
-                       mlog_errno(ret);
-                       goto out_free;
-               }
+               if (cpos >= emi->ei_cpos && cpos < range) {
+                       list_move(&emi->ei_list, &em->em_list);
 
-               if (eb_bh) {
-                       brelse(eb_bh);
-                       eb_bh = NULL;
-               }
-               ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
-                                      blkno, &eb_bh, OCFS2_BH_CACHED,
-                                      inode);
-               if (ret) {
-                       mlog_errno(ret);
-                       goto out_free;
-               }
-               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);
-                       ret = -EIO;
-                       goto out_free;
+                       *ret_emi = emi;
+                       break;
                }
-               el = &eb->h_list;
        }
+}
 
-       BUG_ON(el->l_tree_depth);
-
-       for (i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
-               rec = &el->l_recs[i];
-               ret = ocfs2_extent_map_insert(inode, rec,
-                                             le16_to_cpu(el->l_tree_depth));
-               if (ret) {
-                       mlog_errno(ret);
-                       goto out_free;
-               }
+static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
+                                  unsigned int *phys, unsigned int *len,
+                                  unsigned int *flags)
+{
+       unsigned int coff;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+       struct ocfs2_extent_map_item *emi;
+
+       spin_lock(&oi->ip_lock);
+
+       __ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
+       if (emi) {
+               coff = cpos - emi->ei_cpos;
+               *phys = emi->ei_phys + coff;
+               if (len)
+                       *len = emi->ei_clusters - coff;
+               if (flags)
+                       *flags = emi->ei_flags;
        }
 
-       ret = 0;
+       spin_unlock(&oi->ip_lock);
 
-out_free:
-       if (eb_bh)
-               brelse(eb_bh);
+       if (emi == NULL)
+               return -ENOENT;
 
-       return ret;
+       return 0;
 }
 
 /*
- * This lookup actually will read from disk.  It has one invariant:
- * It will never re-traverse blocks.  This means that all inserts should
- * be new regions or more granular regions (both allowed by insert).
+ * Forget about all clusters equal to or greater than cpos.
  */
-static int ocfs2_extent_map_lookup_read(struct inode *inode,
-                                       u32 cpos,
-                                       u32 clusters,
-                                       struct ocfs2_extent_map_entry **ret_ent)
+void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
 {
-       int ret;
-       u64 blkno;
-       struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
-       struct ocfs2_extent_map_entry *ent;
-       struct buffer_head *bh = NULL;
-       struct ocfs2_extent_block *eb;
-       struct ocfs2_dinode *di;
-       struct ocfs2_extent_list *el;
-
-       spin_lock(&OCFS2_I(inode)->ip_lock);
-       ent = ocfs2_extent_map_lookup(em, cpos, clusters, NULL, NULL);
-       if (ent) {
-               if (!ent->e_tree_depth) {
-                       spin_unlock(&OCFS2_I(inode)->ip_lock);
-                       *ret_ent = ent;
-                       return 0;
-               }
-               blkno = le64_to_cpu(ent->e_rec.e_blkno);
-               spin_unlock(&OCFS2_I(inode)->ip_lock);
-
-               ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), blkno, &bh,
-                                      OCFS2_BH_CACHED, inode);
-               if (ret) {
-                       mlog_errno(ret);
-                       if (bh)
-                               brelse(bh);
-                       return ret;
+       struct ocfs2_extent_map_item *emi, *n;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+       struct ocfs2_extent_map *em = &oi->ip_extent_map;
+       LIST_HEAD(tmp_list);
+       unsigned int range;
+
+       spin_lock(&oi->ip_lock);
+       list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
+               if (emi->ei_cpos >= cpos) {
+                       /* Full truncate of this record. */
+                       list_move(&emi->ei_list, &tmp_list);
+                       BUG_ON(em->em_num_items == 0);
+                       em->em_num_items--;
+                       continue;
                }
-               eb = (struct ocfs2_extent_block *)bh->b_data;
-               if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
-                       OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
-                       brelse(bh);
-                       return -EIO;
-               }
-               el = &eb->h_list;
-       } else {
-               spin_unlock(&OCFS2_I(inode)->ip_lock);
 
-               ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
-                                      OCFS2_I(inode)->ip_blkno, &bh,
-                                      OCFS2_BH_CACHED, inode);
-               if (ret) {
-                       mlog_errno(ret);
-                       if (bh)
-                               brelse(bh);
-                       return ret;
-               }
-               di = (struct ocfs2_dinode *)bh->b_data;
-               if (!OCFS2_IS_VALID_DINODE(di)) {
-                       brelse(bh);
-                       OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, di);
-                       return -EIO;
+               range = emi->ei_cpos + emi->ei_clusters;
+               if (range > cpos) {
+                       /* Partial truncate */
+                       emi->ei_clusters = cpos - emi->ei_cpos;
                }
-               el = &di->id2.i_list;
        }
+       spin_unlock(&oi->ip_lock);
 
-       ret = ocfs2_extent_map_find_leaf(inode, cpos, clusters, el);
-       brelse(bh);
-       if (ret) {
-               mlog_errno(ret);
-               return ret;
+       list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
+               list_del(&emi->ei_list);
+               kfree(emi);
        }
-
-       ent = ocfs2_extent_map_lookup(em, cpos, clusters, NULL, NULL);
-       if (!ent) {
-               ret = -ESRCH;
-               mlog_errno(ret);
-               return ret;
-       }
-
-       /* FIXME: Make sure this isn't a corruption */
-       BUG_ON(ent->e_tree_depth);
-
-       *ret_ent = ent;
-
-       return 0;
 }
 
 /*
- * Callers must hold ip_lock.  This can insert pieces of the tree,
- * thus racing lookup if the lock weren't held.
+ * Is any part of emi2 contained within emi1
  */
-static int ocfs2_extent_map_insert_entry(struct ocfs2_extent_map *em,
-                                        struct ocfs2_extent_map_entry *ent)
+static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
+                                struct ocfs2_extent_map_item *emi2)
 {
-       struct rb_node **p, *parent;
-       struct ocfs2_extent_map_entry *old_ent;
+       unsigned int range1, range2;
 
-       old_ent = ocfs2_extent_map_lookup(em, le32_to_cpu(ent->e_rec.e_cpos),
-                                         le32_to_cpu(ent->e_rec.e_clusters),
-                                         &p, &parent);
-       if (old_ent)
-               return -EEXIST;
+       /*
+        * Check if logical start of emi2 is inside emi1
+        */
+       range1 = emi1->ei_cpos + emi1->ei_clusters;
+       if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
+               return 1;
 
-       rb_link_node(&ent->e_node, parent, p);
-       rb_insert_color(&ent->e_node, &em->em_extents);
+       /*
+        * Check if logical end of emi2 is inside emi1
+        */
+       range2 = emi2->ei_cpos + emi2->ei_clusters;
+       if (range2 > emi1->ei_cpos && range2 <= range1)
+               return 1;
 
        return 0;
 }
 
+static void ocfs2_copy_emi_fields(struct ocfs2_extent_map_item *dest,
+                                 struct ocfs2_extent_map_item *src)
+{
+       dest->ei_cpos = src->ei_cpos;
+       dest->ei_phys = src->ei_phys;
+       dest->ei_clusters = src->ei_clusters;
+       dest->ei_flags = src->ei_flags;
+}
 
 /*
- * Simple rule: on any return code other than -EAGAIN, anything left
- * in the insert_context will be freed.
+ * Try to merge emi with ins. Returns 1 if merge succeeds, zero
+ * otherwise.
  */
-static int ocfs2_extent_map_try_insert(struct inode *inode,
-                                      struct ocfs2_extent_rec *rec,
-                                      int tree_depth,
-                                      struct ocfs2_em_insert_context *ctxt)
+static int ocfs2_try_to_merge_extent_map(struct ocfs2_extent_map_item *emi,
+                                        struct ocfs2_extent_map_item *ins)
 {
-       int ret;
-       struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
-       struct ocfs2_extent_map_entry *old_ent;
-
-       ctxt->need_left = 0;
-       ctxt->need_right = 0;
-       ctxt->old_ent = NULL;
-
-       spin_lock(&OCFS2_I(inode)->ip_lock);
-       ret = ocfs2_extent_map_insert_entry(em, ctxt->new_ent);
-       if (!ret) {
-               ctxt->new_ent = NULL;
-               goto out_unlock;
+       /*
+        * Handle contiguousness
+        */
+       if (ins->ei_phys == (emi->ei_phys + emi->ei_clusters) &&
+           ins->ei_cpos == (emi->ei_cpos + emi->ei_clusters) &&
+           ins->ei_flags == emi->ei_flags) {
+               emi->ei_clusters += ins->ei_clusters;
+               return 1;
+       } else if ((ins->ei_phys + ins->ei_clusters) == emi->ei_phys &&
+                  (ins->ei_cpos + ins->ei_clusters) == emi->ei_phys &&
+                  ins->ei_flags == emi->ei_flags) {
+               emi->ei_phys = ins->ei_phys;
+               emi->ei_cpos = ins->ei_cpos;
+               emi->ei_clusters += ins->ei_clusters;
+               return 1;
        }
 
-       old_ent = ocfs2_extent_map_lookup(em, le32_to_cpu(rec->e_cpos),
-                                         le32_to_cpu(rec->e_clusters), NULL,
-                                         NULL);
-
-       BUG_ON(!old_ent);
-
-       ret = -EEXIST;
-       if (old_ent->e_tree_depth < tree_depth)
-               goto out_unlock;
+       /*
+        * Overlapping extents - this shouldn't happen unless we've
+        * split an extent to change it's flags. That is exceedingly
+        * rare, so there's no sense in trying to optimize it yet.
+        */
+       if (ocfs2_ei_is_contained(emi, ins) ||
+           ocfs2_ei_is_contained(ins, emi)) {
+               ocfs2_copy_emi_fields(emi, ins);
+               return 1;
+       }
 
-       if (old_ent->e_tree_depth == tree_depth) {
-               if (!memcmp(rec, &old_ent->e_rec,
-                           sizeof(struct ocfs2_extent_rec)))
-                       ret = 0;
+       /* No merge was possible. */
+       return 0;
+}
 
-               /* FIXME: Should this be ESRCH/EBADR??? */
-               goto out_unlock;
+/*
+ * In order to reduce complexity on the caller, this insert function
+ * is intentionally liberal in what it will accept.
+ *
+ * The only rule is that the truncate call *must* be used whenever
+ * records have been deleted. This avoids inserting overlapping
+ * records with different physical mappings.
+ */
+void ocfs2_extent_map_insert_rec(struct inode *inode,
+                                struct ocfs2_extent_rec *rec)
+{
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+       struct ocfs2_extent_map *em = &oi->ip_extent_map;
+       struct ocfs2_extent_map_item *emi, *new_emi = NULL;
+       struct ocfs2_extent_map_item ins;
+
+       ins.ei_cpos = le32_to_cpu(rec->e_cpos);
+       ins.ei_phys = ocfs2_blocks_to_clusters(inode->i_sb,
+                                              le64_to_cpu(rec->e_blkno));
+       ins.ei_clusters = le16_to_cpu(rec->e_leaf_clusters);
+       ins.ei_flags = rec->e_flags;
+
+search:
+       spin_lock(&oi->ip_lock);
+
+       list_for_each_entry(emi, &em->em_list, ei_list) {
+               if (ocfs2_try_to_merge_extent_map(emi, &ins)) {
+                       list_move(&emi->ei_list, &em->em_list);
+                       spin_unlock(&oi->ip_lock);
+                       goto out;
+               }
        }
 
        /*
-        * We do it in this order specifically so that no actual tree
-        * changes occur until we have all the pieces we need.  We
-        * don't want malloc failures to leave an inconsistent tree.
-        * Whenever we drop the lock, another process could be
-        * inserting.  Also note that, if another process just beat us
-        * to an insert, we might not need the same pieces we needed
-        * the first go round.  In the end, the pieces we need will
-        * be used, and the pieces we don't will be freed.
+        * No item could be merged.
+        *
+        * Either allocate and add a new item, or overwrite the last recently
+        * inserted.
         */
-       ctxt->need_left = !!(le32_to_cpu(rec->e_cpos) >
-                            le32_to_cpu(old_ent->e_rec.e_cpos));
-       ctxt->need_right = !!((le32_to_cpu(old_ent->e_rec.e_cpos) +
-                              le32_to_cpu(old_ent->e_rec.e_clusters)) >
-                             (le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)));
-       ret = -EAGAIN;
-       if (ctxt->need_left) {
-               if (!ctxt->left_ent)
-                       goto out_unlock;
-               *(ctxt->left_ent) = *old_ent;
-               ctxt->left_ent->e_rec.e_clusters =
-                       cpu_to_le32(le32_to_cpu(rec->e_cpos) -
-                                   le32_to_cpu(ctxt->left_ent->e_rec.e_cpos));
-       }
-       if (ctxt->need_right) {
-               if (!ctxt->right_ent)
-                       goto out_unlock;
-               *(ctxt->right_ent) = *old_ent;
-               ctxt->right_ent->e_rec.e_cpos =
-                       cpu_to_le32(le32_to_cpu(rec->e_cpos) +
-                                   le32_to_cpu(rec->e_clusters));
-               ctxt->right_ent->e_rec.e_clusters =
-                       cpu_to_le32((le32_to_cpu(old_ent->e_rec.e_cpos) +
-                                    le32_to_cpu(old_ent->e_rec.e_clusters)) -
-                                   le32_to_cpu(ctxt->right_ent->e_rec.e_cpos));
-       }
-
-       rb_erase(&old_ent->e_node, &em->em_extents);
-       /* Now that he's erased, set him up for deletion */
-       ctxt->old_ent = old_ent;
-
-       if (ctxt->need_left) {
-               ret = ocfs2_extent_map_insert_entry(em,
-                                                   ctxt->left_ent);
-               if (ret)
-                       goto out_unlock;
-               ctxt->left_ent = NULL;
-       }
 
-       if (ctxt->need_right) {
-               ret = ocfs2_extent_map_insert_entry(em,
-                                                   ctxt->right_ent);
-               if (ret)
-                       goto out_unlock;
-               ctxt->right_ent = NULL;
-       }
+       if (em->em_num_items < OCFS2_MAX_EXTENT_MAP_ITEMS) {
+               if (new_emi == NULL) {
+                       spin_unlock(&oi->ip_lock);
 
-       ret = ocfs2_extent_map_insert_entry(em, ctxt->new_ent);
+                       new_emi = kmalloc(sizeof(*new_emi), GFP_NOFS);
+                       if (new_emi == NULL)
+                               goto out;
 
-       if (!ret)
-               ctxt->new_ent = NULL;
+                       goto search;
+               }
 
-out_unlock:
-       spin_unlock(&OCFS2_I(inode)->ip_lock);
+               ocfs2_copy_emi_fields(new_emi, &ins);
+               list_add(&new_emi->ei_list, &em->em_list);
+               em->em_num_items++;
+               new_emi = NULL;
+       } else {
+               BUG_ON(list_empty(&em->em_list) || em->em_num_items == 0);
+               emi = list_entry(em->em_list.prev,
+                                struct ocfs2_extent_map_item, ei_list);
+               list_move(&emi->ei_list, &em->em_list);
+               ocfs2_copy_emi_fields(emi, &ins);
+       }
 
-       return ret;
-}
+       spin_unlock(&oi->ip_lock);
 
+out:
+       if (new_emi)
+               kfree(new_emi);
+}
 
-static int ocfs2_extent_map_insert(struct inode *inode,
-                                  struct ocfs2_extent_rec *rec,
-                                  int tree_depth)
+static int ocfs2_last_eb_is_empty(struct inode *inode,
+                                 struct ocfs2_dinode *di)
 {
-       int ret;
-       struct ocfs2_em_insert_context ctxt = {0, };
+       int ret, next_free;
+       u64 last_eb_blk = le64_to_cpu(di->i_last_eb_blk);
+       struct buffer_head *eb_bh = NULL;
+       struct ocfs2_extent_block *eb;
+       struct ocfs2_extent_list *el;
 
-       if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) >
-           OCFS2_I(inode)->ip_map.em_clusters) {
-               ret = -EBADR;
+       ret = ocfs2_read_extent_block(INODE_CACHE(inode), last_eb_blk, &eb_bh);
+       if (ret) {
                mlog_errno(ret);
-               return ret;
+               goto out;
        }
 
-       /* Zero e_clusters means a truncated tail record.  It better be EOF */
-       if (!rec->e_clusters) {
-               if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) !=
-                   OCFS2_I(inode)->ip_map.em_clusters) {
-                       ret = -EBADR;
-                       mlog_errno(ret);
-                       return ret;
-               }
+       eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+       el = &eb->h_list;
 
-               /* Ignore the truncated tail */
-               return 0;
+       if (el->l_tree_depth) {
+               ocfs2_error(inode->i_sb,
+                           "Inode %lu has non zero tree depth in "
+                           "leaf block %llu\n", inode->i_ino,
+                           (unsigned long long)eb_bh->b_blocknr);
+               ret = -EROFS;
+               goto out;
        }
 
-       ret = -ENOMEM;
-       ctxt.new_ent = kmem_cache_alloc(ocfs2_em_ent_cachep,
-                                       GFP_KERNEL);
-       if (!ctxt.new_ent) {
-               mlog_errno(ret);
-               return ret;
-       }
-
-       ctxt.new_ent->e_rec = *rec;
-       ctxt.new_ent->e_tree_depth = tree_depth;
-
-       do {
-               ret = -ENOMEM;
-               if (ctxt.need_left && !ctxt.left_ent) {
-                       ctxt.left_ent =
-                               kmem_cache_alloc(ocfs2_em_ent_cachep,
-                                                GFP_KERNEL);
-                       if (!ctxt.left_ent)
-                               break;
-               }
-               if (ctxt.need_right && !ctxt.right_ent) {
-                       ctxt.right_ent =
-                               kmem_cache_alloc(ocfs2_em_ent_cachep,
-                                                GFP_KERNEL);
-                       if (!ctxt.right_ent)
-                               break;
-               }
-
-               ret = ocfs2_extent_map_try_insert(inode, rec,
-                                                 tree_depth, &ctxt);
-       } while (ret == -EAGAIN);
-
-       if (ret < 0)
-               mlog_errno(ret);
+       next_free = le16_to_cpu(el->l_next_free_rec);
 
-       if (ctxt.left_ent)
-               kmem_cache_free(ocfs2_em_ent_cachep, ctxt.left_ent);
-       if (ctxt.right_ent)
-               kmem_cache_free(ocfs2_em_ent_cachep, ctxt.right_ent);
-       if (ctxt.old_ent)
-               kmem_cache_free(ocfs2_em_ent_cachep, ctxt.old_ent);
-       if (ctxt.new_ent)
-               kmem_cache_free(ocfs2_em_ent_cachep, ctxt.new_ent);
+       if (next_free == 0 ||
+           (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0])))
+               ret = 1;
 
+out:
+       brelse(eb_bh);
        return ret;
 }
 
 /*
- * Append this record to the tail of the extent map.  It must be
- * tree_depth 0.  The record might be an extension of an existing
- * record, and as such that needs to be handled.  eg:
- *
- * Existing record in the extent map:
- *
- *     cpos = 10, len = 10
- *     |---------|
- *
- * New Record:
- *
- *     cpos = 10, len = 20
- *     |------------------|
- *
- * The passed record is the new on-disk record.  The new_clusters value
- * is how many clusters were added to the file.  If the append is a
- * contiguous append, the new_clusters has been added to
- * rec->e_clusters.  If the append is an entirely new extent, then
- * rec->e_clusters is == new_clusters.
+ * Return the 1st index within el which contains an extent start
+ * larger than v_cluster.
  */
-int ocfs2_extent_map_append(struct inode *inode,
-                           struct ocfs2_extent_rec *rec,
-                           u32 new_clusters)
+static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
+                                      u32 v_cluster)
 {
-       int ret;
-       struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
-       struct ocfs2_extent_map_entry *ent;
-       struct ocfs2_extent_rec *old;
+       int i;
+       struct ocfs2_extent_rec *rec;
 
-       BUG_ON(!new_clusters);
-       BUG_ON(le32_to_cpu(rec->e_clusters) < new_clusters);
+       for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
+               rec = &el->l_recs[i];
 
-       if (em->em_clusters < OCFS2_I(inode)->ip_clusters) {
-               /*
-                * Size changed underneath us on disk.  Drop any
-                * straddling records and update our idea of
-                * i_clusters
-                */
-               ocfs2_extent_map_drop(inode, em->em_clusters - 1);
-               em->em_clusters = OCFS2_I(inode)->ip_clusters;
-       }
-
-       mlog_bug_on_msg((le32_to_cpu(rec->e_cpos) +
-                        le32_to_cpu(rec->e_clusters)) !=
-                       (em->em_clusters + new_clusters),
-                       "Inode %"MLFu64":\n"
-                       "rec->e_cpos = %u + rec->e_clusters = %u = %u\n"
-                       "em->em_clusters = %u + new_clusters = %u = %u\n",
-                       OCFS2_I(inode)->ip_blkno,
-                       le32_to_cpu(rec->e_cpos), le32_to_cpu(rec->e_clusters),
-                       le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters),
-                       em->em_clusters, new_clusters,
-                       em->em_clusters + new_clusters);
-
-       em->em_clusters += new_clusters;
-
-       ret = -ENOENT;
-       if (le32_to_cpu(rec->e_clusters) > new_clusters) {
-               /* This is a contiguous append */
-               ent = ocfs2_extent_map_lookup(em, le32_to_cpu(rec->e_cpos), 1,
-                                             NULL, NULL);
-               if (ent) {
-                       old = &ent->e_rec;
-                       BUG_ON((le32_to_cpu(rec->e_cpos) +
-                               le32_to_cpu(rec->e_clusters)) !=
-                                (le32_to_cpu(old->e_cpos) +
-                                 le32_to_cpu(old->e_clusters) +
-                                 new_clusters));
-                       if (ent->e_tree_depth == 0) {
-                               BUG_ON(le32_to_cpu(old->e_cpos) !=
-                                      le32_to_cpu(rec->e_cpos));
-                               BUG_ON(le64_to_cpu(old->e_blkno) !=
-                                      le64_to_cpu(rec->e_blkno));
-                               ret = 0;
-                       }
-                       /*
-                        * Let non-leafs fall through as -ENOENT to
-                        * force insertion of the new leaf.
-                        */
-                       le32_add_cpu(&old->e_clusters, new_clusters);
-               }
+               if (v_cluster < le32_to_cpu(rec->e_cpos))
+                       break;
        }
 
-       if (ret == -ENOENT)
-               ret = ocfs2_extent_map_insert(inode, rec, 0);
-       if (ret < 0)
-               mlog_errno(ret);
-       return ret;
+       return i;
 }
 
-#if 0
-/* Code here is included but defined out as it completes the extent
- * map api and may be used in the future. */
-
 /*
- * Look up the record containing this cluster offset.  This record is
- * part of the extent map.  Do not free it.  Any changes you make to
- * it will reflect in the extent map.  So, if your last extent
- * is (cpos = 10, clusters = 10) and you truncate the file by 5
- * clusters, you can do:
- *
- * ret = ocfs2_extent_map_get_rec(em, orig_size - 5, &rec);
- * rec->e_clusters -= 5;
+ * Figure out the size of a hole which starts at v_cluster within the given
+ * extent list.
  *
- * The lookup does not read from disk.  If the map isn't filled in for
- * an entry, you won't find it.
+ * If there is no more allocation past v_cluster, we return the maximum
+ * cluster size minus v_cluster.
  *
- * Also note that the returned record is valid until alloc_sem is
- * dropped.  After that, truncate and extend can happen.  Caveat Emptor.
+ * If we have in-inode extents, then el points to the dinode list and
+ * eb_bh is NULL. Otherwise, eb_bh should point to the extent block
+ * containing el.
  */
-int ocfs2_extent_map_get_rec(struct inode *inode, u32 cpos,
-                            struct ocfs2_extent_rec **rec,
-                            int *tree_depth)
+int ocfs2_figure_hole_clusters(struct ocfs2_caching_info *ci,
+                              struct ocfs2_extent_list *el,
+                              struct buffer_head *eb_bh,
+                              u32 v_cluster,
+                              u32 *num_clusters)
 {
-       int ret = -ENOENT;
-       struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
-       struct ocfs2_extent_map_entry *ent;
+       int ret, i;
+       struct buffer_head *next_eb_bh = NULL;
+       struct ocfs2_extent_block *eb, *next_eb;
 
-       *rec = NULL;
+       i = ocfs2_search_for_hole_index(el, v_cluster);
 
-       if (cpos >= OCFS2_I(inode)->ip_clusters)
-               return -EINVAL;
+       if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
+               eb = (struct ocfs2_extent_block *)eb_bh->b_data;
 
-       if (cpos >= em->em_clusters) {
                /*
-                * Size changed underneath us on disk.  Drop any
-                * straddling records and update our idea of
-                * i_clusters
+                * Check the next leaf for any extents.
                 */
-               ocfs2_extent_map_drop(inode, em->em_clusters - 1);
-               em->em_clusters = OCFS2_I(inode)->ip_clusters ;
-       }
 
-       ent = ocfs2_extent_map_lookup(&OCFS2_I(inode)->ip_map, cpos, 1,
-                                     NULL, NULL);
+               if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
+                       goto no_more_extents;
 
-       if (ent) {
-               *rec = &ent->e_rec;
-               if (tree_depth)
-                       *tree_depth = ent->e_tree_depth;
-               ret = 0;
+               ret = ocfs2_read_extent_block(ci,
+                                             le64_to_cpu(eb->h_next_leaf_blk),
+                                             &next_eb_bh);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
+               el = &next_eb->h_list;
+               i = ocfs2_search_for_hole_index(el, v_cluster);
        }
 
+no_more_extents:
+       if (i == le16_to_cpu(el->l_next_free_rec)) {
+               /*
+                * We're at the end of our existing allocation. Just
+                * return the maximum number of clusters we could
+                * possibly allocate.
+                */
+               *num_clusters = UINT_MAX - v_cluster;
+       } else {
+               *num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
+       }
+
+       ret = 0;
+out:
+       brelse(next_eb_bh);
        return ret;
 }
 
-int ocfs2_extent_map_get_clusters(struct inode *inode,
-                                 u32 v_cpos, int count,
-                                 u32 *p_cpos, int *ret_count)
+static int ocfs2_get_clusters_nocache(struct inode *inode,
+                                     struct buffer_head *di_bh,
+                                     u32 v_cluster, unsigned int *hole_len,
+                                     struct ocfs2_extent_rec *ret_rec,
+                                     unsigned int *is_last)
 {
-       int ret;
-       u32 coff, ccount;
-       struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
-       struct ocfs2_extent_map_entry *ent = NULL;
+       int i, ret, tree_height, len;
+       struct ocfs2_dinode *di;
+       struct ocfs2_extent_block *uninitialized_var(eb);
+       struct ocfs2_extent_list *el;
+       struct ocfs2_extent_rec *rec;
+       struct buffer_head *eb_bh = NULL;
+
+       memset(ret_rec, 0, sizeof(*ret_rec));
+       if (is_last)
+               *is_last = 0;
+
+       di = (struct ocfs2_dinode *) di_bh->b_data;
+       el = &di->id2.i_list;
+       tree_height = le16_to_cpu(el->l_tree_depth);
+
+       if (tree_height > 0) {
+               ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
+                                     &eb_bh);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
 
-       *p_cpos = ccount = 0;
+               eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+               el = &eb->h_list;
 
-       if ((v_cpos + count) > OCFS2_I(inode)->ip_clusters)
-               return -EINVAL;
+               if (el->l_tree_depth) {
+                       ocfs2_error(inode->i_sb,
+                                   "Inode %lu has non zero tree depth in "
+                                   "leaf block %llu\n", inode->i_ino,
+                                   (unsigned long long)eb_bh->b_blocknr);
+                       ret = -EROFS;
+                       goto out;
+               }
+       }
 
-       if ((v_cpos + count) > em->em_clusters) {
+       i = ocfs2_search_extent_list(el, v_cluster);
+       if (i == -1) {
                /*
-                * Size changed underneath us on disk.  Drop any
-                * straddling records and update our idea of
-                * i_clusters
+                * Holes can be larger than the maximum size of an
+                * extent, so we return their lengths in a seperate
+                * field.
                 */
-               ocfs2_extent_map_drop(inode, em->em_clusters - 1);
-               em->em_clusters = OCFS2_I(inode)->ip_clusters;
-       }
+               if (hole_len) {
+                       ret = ocfs2_figure_hole_clusters(INODE_CACHE(inode),
+                                                        el, eb_bh,
+                                                        v_cluster, &len);
+                       if (ret) {
+                               mlog_errno(ret);
+                               goto out;
+                       }
 
+                       *hole_len = len;
+               }
+               goto out_hole;
+       }
 
-       ret = ocfs2_extent_map_lookup_read(inode, v_cpos, count, &ent);
-       if (ret)
-               return ret;
+       rec = &el->l_recs[i];
 
-       if (ent) {
-               /* We should never find ourselves straddling an interval */
-               if (!ocfs2_extent_rec_contains_clusters(&ent->e_rec,
-                                                       v_cpos,
-                                                       count))
-                       return -ESRCH;
+       BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
 
-               coff = v_cpos - le32_to_cpu(ent->e_rec.e_cpos);
-               *p_cpos = ocfs2_blocks_to_clusters(inode->i_sb,
-                               le64_to_cpu(ent->e_rec.e_blkno)) +
-                         coff;
+       if (!rec->e_blkno) {
+               ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
+                           "record (%u, %u, 0)", inode->i_ino,
+                           le32_to_cpu(rec->e_cpos),
+                           ocfs2_rec_clusters(el, rec));
+               ret = -EROFS;
+               goto out;
+       }
 
-               if (ret_count)
-                       *ret_count = le32_to_cpu(ent->e_rec.e_clusters) - coff;
+       *ret_rec = *rec;
 
-               return 0;
+       /*
+        * Checking for last extent is potentially expensive - we
+        * might have to look at the next leaf over to see if it's
+        * empty.
+        *
+        * The first two checks are to see whether the caller even
+        * cares for this information, and if the extent is at least
+        * the last in it's list.
+        *
+        * If those hold true, then the extent is last if any of the
+        * additional conditions hold true:
+        *  - Extent list is in-inode
+        *  - Extent list is right-most
+        *  - Extent list is 2nd to rightmost, with empty right-most
+        */
+       if (is_last) {
+               if (i == (le16_to_cpu(el->l_next_free_rec) - 1)) {
+                       if (tree_height == 0)
+                               *is_last = 1;
+                       else if (eb->h_blkno == di->i_last_eb_blk)
+                               *is_last = 1;
+                       else if (eb->h_next_leaf_blk == di->i_last_eb_blk) {
+                               ret = ocfs2_last_eb_is_empty(inode, di);
+                               if (ret < 0) {
+                                       mlog_errno(ret);
+                                       goto out;
+                               }
+                               if (ret == 1)
+                                       *is_last = 1;
+                       }
+               }
        }
 
-
-       return -ENOENT;
+out_hole:
+       ret = 0;
+out:
+       brelse(eb_bh);
+       return ret;
 }
 
-#endif  /*  0  */
+static void ocfs2_relative_extent_offsets(struct super_block *sb,
+                                         u32 v_cluster,
+                                         struct ocfs2_extent_rec *rec,
+                                         u32 *p_cluster, u32 *num_clusters)
 
-int ocfs2_extent_map_get_blocks(struct inode *inode,
-                               u64 v_blkno, int count,
-                               u64 *p_blkno, int *ret_count)
 {
-       int ret;
-       u64 boff;
-       u32 cpos, clusters;
-       int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
-       struct ocfs2_extent_map_entry *ent = NULL;
-       struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
+       u32 coff = v_cluster - le32_to_cpu(rec->e_cpos);
+
+       *p_cluster = ocfs2_blocks_to_clusters(sb, le64_to_cpu(rec->e_blkno));
+       *p_cluster = *p_cluster + coff;
+
+       if (num_clusters)
+               *num_clusters = le16_to_cpu(rec->e_leaf_clusters) - coff;
+}
+
+int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
+                            u32 *p_cluster, u32 *num_clusters,
+                            struct ocfs2_extent_list *el,
+                            unsigned int *extent_flags)
+{
+       int ret = 0, i;
+       struct buffer_head *eb_bh = NULL;
+       struct ocfs2_extent_block *eb;
        struct ocfs2_extent_rec *rec;
+       u32 coff;
 
-       *p_blkno = 0;
+       if (el->l_tree_depth) {
+               ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
+                                     &eb_bh);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
 
-       cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
-       clusters = ocfs2_blocks_to_clusters(inode->i_sb,
-                                           (u64)count + bpc - 1);
-       if ((cpos + clusters) > OCFS2_I(inode)->ip_clusters) {
-               ret = -EINVAL;
-               mlog_errno(ret);
-               return ret;
-       }
+               eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+               el = &eb->h_list;
 
-       if ((cpos + clusters) > em->em_clusters) {
-               /*
-                * Size changed underneath us on disk.  Drop any
-                * straddling records and update our idea of
-                * i_clusters
-                */
-               ocfs2_extent_map_drop(inode, em->em_clusters - 1);
-               em->em_clusters = OCFS2_I(inode)->ip_clusters;
+               if (el->l_tree_depth) {
+                       ocfs2_error(inode->i_sb,
+                                   "Inode %lu has non zero tree depth in "
+                                   "xattr leaf block %llu\n", inode->i_ino,
+                                   (unsigned long long)eb_bh->b_blocknr);
+                       ret = -EROFS;
+                       goto out;
+               }
        }
 
-       ret = ocfs2_extent_map_lookup_read(inode, cpos, clusters, &ent);
-       if (ret) {
+       i = ocfs2_search_extent_list(el, v_cluster);
+       if (i == -1) {
+               ret = -EROFS;
                mlog_errno(ret);
-               return ret;
+               goto out;
+       } else {
+               rec = &el->l_recs[i];
+               BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
+
+               if (!rec->e_blkno) {
+                       ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
+                                   "record (%u, %u, 0) in xattr", inode->i_ino,
+                                   le32_to_cpu(rec->e_cpos),
+                                   ocfs2_rec_clusters(el, rec));
+                       ret = -EROFS;
+                       goto out;
+               }
+               coff = v_cluster - le32_to_cpu(rec->e_cpos);
+               *p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
+                                                   le64_to_cpu(rec->e_blkno));
+               *p_cluster = *p_cluster + coff;
+               if (num_clusters)
+                       *num_clusters = ocfs2_rec_clusters(el, rec) - coff;
+
+               if (extent_flags)
+                       *extent_flags = rec->e_flags;
        }
+out:
+       if (eb_bh)
+               brelse(eb_bh);
+       return ret;
+}
 
-       if (ent)
-       {
-               rec = &ent->e_rec;
+int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
+                      u32 *p_cluster, u32 *num_clusters,
+                      unsigned int *extent_flags)
+{
+       int ret;
+       unsigned int uninitialized_var(hole_len), flags = 0;
+       struct buffer_head *di_bh = NULL;
+       struct ocfs2_extent_rec rec;
 
-               /* We should never find ourselves straddling an interval */
-               if (!ocfs2_extent_rec_contains_clusters(rec, cpos, clusters)) {
-                       ret = -ESRCH;
-                       mlog_errno(ret);
-                       return ret;
-               }
+       if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
+               ret = -ERANGE;
+               mlog_errno(ret);
+               goto out;
+       }
 
-               boff = ocfs2_clusters_to_blocks(inode->i_sb, cpos -
-                                               le32_to_cpu(rec->e_cpos));
-               boff += (v_blkno & (u64)(bpc - 1));
-               *p_blkno = le64_to_cpu(rec->e_blkno) + boff;
+       ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
+                                     num_clusters, extent_flags);
+       if (ret == 0)
+               goto out;
 
-               if (ret_count) {
-                       *ret_count = ocfs2_clusters_to_blocks(inode->i_sb,
-                                       le32_to_cpu(rec->e_clusters)) - boff;
-               }
+       ret = ocfs2_read_inode_block(inode, &di_bh);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
 
-               return 0;
+       ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
+                                        &rec, NULL);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
        }
 
-       return -ENOENT;
-}
+       if (rec.e_blkno == 0ULL) {
+               /*
+                * A hole was found. Return some canned values that
+                * callers can key on. If asked for, num_clusters will
+                * be populated with the size of the hole.
+                */
+               *p_cluster = 0;
+               if (num_clusters) {
+                       *num_clusters = hole_len;
+               }
+       } else {
+               ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
+                                             p_cluster, num_clusters);
+               flags = rec.e_flags;
 
-int ocfs2_extent_map_init(struct inode *inode)
-{
-       struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
+               ocfs2_extent_map_insert_rec(inode, &rec);
+       }
 
-       em->em_extents = RB_ROOT;
-       em->em_clusters = 0;
+       if (extent_flags)
+               *extent_flags = flags;
 
-       return 0;
+out:
+       brelse(di_bh);
+       return ret;
 }
 
-/* Needs the lock */
-static void __ocfs2_extent_map_drop(struct inode *inode,
-                                   u32 new_clusters,
-                                   struct rb_node **free_head,
-                                   struct ocfs2_extent_map_entry **tail_ent)
+/*
+ * This expects alloc_sem to be held. The allocation cannot change at
+ * all while the map is in the process of being updated.
+ */
+int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
+                               u64 *ret_count, unsigned int *extent_flags)
 {
-       struct rb_node *node, *next;
-       struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
-       struct ocfs2_extent_map_entry *ent;
-
-       *free_head = NULL;
+       int ret;
+       int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
+       u32 cpos, num_clusters, p_cluster;
+       u64 boff = 0;
 
-       ent = NULL;
-       node = rb_last(&em->em_extents);
-       while (node)
-       {
-               next = rb_prev(node);
+       cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
 
-               ent = rb_entry(node, struct ocfs2_extent_map_entry,
-                              e_node);
-               if (le32_to_cpu(ent->e_rec.e_cpos) < new_clusters)
-                       break;
+       ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
+                                extent_flags);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
 
-               rb_erase(&ent->e_node, &em->em_extents);
+       /*
+        * p_cluster == 0 indicates a hole.
+        */
+       if (p_cluster) {
+               boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
+               boff += (v_blkno & (u64)(bpc - 1));
+       }
 
-               node->rb_right = *free_head;
-               *free_head = node;
+       *p_blkno = boff;
 
-               ent = NULL;
-               node = next;
+       if (ret_count) {
+               *ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
+               *ret_count -= v_blkno & (u64)(bpc - 1);
        }
 
-       /* Do we have an entry straddling new_clusters? */
-       if (tail_ent) {
-               if (ent &&
-                   ((le32_to_cpu(ent->e_rec.e_cpos) +
-                     le32_to_cpu(ent->e_rec.e_clusters)) > new_clusters))
-                       *tail_ent = ent;
-               else
-                       *tail_ent = NULL;
-       }
+out:
+       return ret;
 }
 
-static void __ocfs2_extent_map_drop_cleanup(struct rb_node *free_head)
+static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
+                              struct fiemap_extent_info *fieinfo,
+                              u64 map_start)
 {
-       struct rb_node *node;
-       struct ocfs2_extent_map_entry *ent;
+       int ret;
+       unsigned int id_count;
+       struct ocfs2_dinode *di;
+       u64 phys;
+       u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+
+       di = (struct ocfs2_dinode *)di_bh->b_data;
+       id_count = le16_to_cpu(di->id2.i_data.id_count);
 
-       while (free_head) {
-               node = free_head;
-               free_head = node->rb_right;
+       if (map_start < id_count) {
+               phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
+               phys += offsetof(struct ocfs2_dinode, id2.i_data.id_data);
 
-               ent = rb_entry(node, struct ocfs2_extent_map_entry,
-                              e_node);
-               kmem_cache_free(ocfs2_em_ent_cachep, ent);
+               ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
+                                             flags);
+               if (ret < 0)
+                       return ret;
        }
+
+       return 0;
 }
 
-/*
- * Remove all entries past new_clusters, inclusive of an entry that
- * contains new_clusters.  This is effectively a cache forget.
- *
- * If you want to also clip the last extent by some number of clusters,
- * you need to call ocfs2_extent_map_trunc().
- * This code does not check or modify ip_clusters.
- */
-int ocfs2_extent_map_drop(struct inode *inode, u32 new_clusters)
+#define OCFS2_FIEMAP_FLAGS     (FIEMAP_FLAG_SYNC)
+
+int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+                u64 map_start, u64 map_len)
 {
-       struct rb_node *free_head = NULL;
-       struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
-       struct ocfs2_extent_map_entry *ent;
+       int ret, is_last;
+       u32 mapping_end, cpos;
+       unsigned int hole_size;
+       struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+       u64 len_bytes, phys_bytes, virt_bytes;
+       struct buffer_head *di_bh = NULL;
+       struct ocfs2_extent_rec rec;
+
+       ret = fiemap_check_flags(fieinfo, OCFS2_FIEMAP_FLAGS);
+       if (ret)
+               return ret;
 
-       spin_lock(&OCFS2_I(inode)->ip_lock);
+       ret = ocfs2_inode_lock(inode, &di_bh, 0);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
 
-       __ocfs2_extent_map_drop(inode, new_clusters, &free_head, &ent);
+       down_read(&OCFS2_I(inode)->ip_alloc_sem);
 
-       if (ent) {
-               rb_erase(&ent->e_node, &em->em_extents);
-               ent->e_node.rb_right = free_head;
-               free_head = &ent->e_node;
+       /*
+        * Handle inline-data separately.
+        */
+       if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
+               ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
+               goto out_unlock;
        }
 
-       spin_unlock(&OCFS2_I(inode)->ip_lock);
+       cpos = map_start >> osb->s_clustersize_bits;
+       mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
+                                              map_start + map_len);
+       mapping_end -= cpos;
+       is_last = 0;
+       while (cpos < mapping_end && !is_last) {
+               u32 fe_flags;
 
-       if (free_head)
-               __ocfs2_extent_map_drop_cleanup(free_head);
-
-       return 0;
-}
+               ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
+                                                &hole_size, &rec, &is_last);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
 
-/*
- * Remove all entries past new_clusters and also clip any extent
- * straddling new_clusters, if there is one.  This does not check
- * or modify ip_clusters
- */
-int ocfs2_extent_map_trunc(struct inode *inode, u32 new_clusters)
-{
-       struct rb_node *free_head = NULL;
-       struct ocfs2_extent_map_entry *ent = NULL;
+               if (rec.e_blkno == 0ULL) {
+                       cpos += hole_size;
+                       continue;
+               }
 
-       spin_lock(&OCFS2_I(inode)->ip_lock);
+               fe_flags = 0;
+               if (rec.e_flags & OCFS2_EXT_UNWRITTEN)
+                       fe_flags |= FIEMAP_EXTENT_UNWRITTEN;
+               if (is_last)
+                       fe_flags |= FIEMAP_EXTENT_LAST;
+               len_bytes = (u64)le16_to_cpu(rec.e_leaf_clusters) << osb->s_clustersize_bits;
+               phys_bytes = le64_to_cpu(rec.e_blkno) << osb->sb->s_blocksize_bits;
+               virt_bytes = (u64)le32_to_cpu(rec.e_cpos) << osb->s_clustersize_bits;
+
+               ret = fiemap_fill_next_extent(fieinfo, virt_bytes, phys_bytes,
+                                             len_bytes, fe_flags);
+               if (ret)
+                       break;
 
-       __ocfs2_extent_map_drop(inode, new_clusters, &free_head, &ent);
+               cpos = le32_to_cpu(rec.e_cpos)+ le16_to_cpu(rec.e_leaf_clusters);
+       }
 
-       if (ent)
-               ent->e_rec.e_clusters = cpu_to_le32(new_clusters -
-                                              le32_to_cpu(ent->e_rec.e_cpos));
+       if (ret > 0)
+               ret = 0;
 
-       OCFS2_I(inode)->ip_map.em_clusters = new_clusters;
+out_unlock:
+       brelse(di_bh);
 
-       spin_unlock(&OCFS2_I(inode)->ip_lock);
+       up_read(&OCFS2_I(inode)->ip_alloc_sem);
 
-       if (free_head)
-               __ocfs2_extent_map_drop_cleanup(free_head);
+       ocfs2_inode_unlock(inode, 0);
+out:
 
-       return 0;
+       return ret;
 }
 
-int __init init_ocfs2_extent_maps(void)
+int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
+                          struct buffer_head *bhs[], int flags,
+                          int (*validate)(struct super_block *sb,
+                                          struct buffer_head *bh))
 {
-       ocfs2_em_ent_cachep =
-               kmem_cache_create("ocfs2_em_ent",
-                                 sizeof(struct ocfs2_extent_map_entry),
-                                 0, SLAB_HWCACHE_ALIGN, NULL, NULL);
-       if (!ocfs2_em_ent_cachep)
-               return -ENOMEM;
+       int rc = 0;
+       u64 p_block, p_count;
+       int i, count, done = 0;
+
+       mlog_entry("(inode = %p, v_block = %llu, nr = %d, bhs = %p, "
+                  "flags = %x, validate = %p)\n",
+                  inode, (unsigned long long)v_block, nr, bhs, flags,
+                  validate);
+
+       if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >=
+           i_size_read(inode)) {
+               BUG_ON(!(flags & OCFS2_BH_READAHEAD));
+               goto out;
+       }
 
-       return 0;
-}
+       while (done < nr) {
+               down_read(&OCFS2_I(inode)->ip_alloc_sem);
+               rc = ocfs2_extent_map_get_blocks(inode, v_block + done,
+                                                &p_block, &p_count, NULL);
+               up_read(&OCFS2_I(inode)->ip_alloc_sem);
+               if (rc) {
+                       mlog_errno(rc);
+                       break;
+               }
 
-void exit_ocfs2_extent_maps(void)
-{
-       kmem_cache_destroy(ocfs2_em_ent_cachep);
+               if (!p_block) {
+                       rc = -EIO;
+                       mlog(ML_ERROR,
+                            "Inode #%llu contains a hole at offset %llu\n",
+                            (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                            (unsigned long long)(v_block + done) <<
+                            inode->i_sb->s_blocksize_bits);
+                       break;
+               }
+
+               count = nr - done;
+               if (p_count < count)
+                       count = p_count;
+
+               /*
+                * If the caller passed us bhs, they should have come
+                * from a previous readahead call to this function.  Thus,
+                * they should have the right b_blocknr.
+                */
+               for (i = 0; i < count; i++) {
+                       if (!bhs[done + i])
+                               continue;
+                       BUG_ON(bhs[done + i]->b_blocknr != (p_block + i));
+               }
+
+               rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, count,
+                                      bhs + done, flags, validate);
+               if (rc) {
+                       mlog_errno(rc);
+                       break;
+               }
+               done += count;
+       }
+
+out:
+       mlog_exit(rc);
+       return rc;
 }
+
+