btrfs-progs: alias btrfs device delete to btrfs device remove
[platform/upstream/btrfs-progs.git] / extent-tree.c
index d0ad017..c24af6a 100644 (file)
@@ -18,6 +18,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdint.h>
 #include "kerncompat.h"
 #include "radix-tree.h"
 #include "ctree.h"
 #include "transaction.h"
 #include "crc32c.h"
 #include "volumes.h"
-
-#define BLOCK_GROUP_DATA     EXTENT_WRITEBACK
-#define BLOCK_GROUP_METADATA EXTENT_UPTODATE
-#define BLOCK_GROUP_SYSTEM   EXTENT_NEW
-
-#define BLOCK_GROUP_DIRTY EXTENT_DIRTY
+#include "free-space-cache.h"
+#include "math.h"
+#include "utils.h"
 
 #define PENDING_EXTENT_INSERT 0
 #define PENDING_EXTENT_DELETE 1
@@ -41,25 +39,28 @@ struct pending_extent_op {
        int type;
        u64 bytenr;
        u64 num_bytes;
-       u64 parent;
-       u64 orig_parent;
-       u64 generation;
-       u64 orig_generation;
+       u64 flags;
+       struct btrfs_disk_key key;
        int level;
 };
 
+static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
+                                    struct btrfs_root *root,
+                                    u64 root_objectid, u64 generation,
+                                    u64 flags, struct btrfs_disk_key *key,
+                                    int level, struct btrfs_key *ins);
+static int __free_extent(struct btrfs_trans_handle *trans,
+                        struct btrfs_root *root,
+                        u64 bytenr, u64 num_bytes, u64 parent,
+                        u64 root_objectid, u64 owner_objectid,
+                        u64 owner_offset, int refs_to_drop);
 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
                                 btrfs_root *extent_root);
 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
                               btrfs_root *extent_root);
-
-void maybe_lock_mutex(struct btrfs_root *root)
-{
-}
-
-void maybe_unlock_mutex(struct btrfs_root *root)
-{
-}
+static struct btrfs_block_group_cache *
+btrfs_find_block_group(struct btrfs_root *root, struct btrfs_block_group_cache
+                      *hint, u64 search_start, int data, int owner);
 
 static int remove_sb_from_cache(struct btrfs_root *root,
                                struct btrfs_block_group_cache *cache)
@@ -115,7 +116,8 @@ static int cache_block_group(struct btrfs_root *root,
        last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
        key.objectid = last;
        key.offset = 0;
-       btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
+       key.type = 0;
+
        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
        if (ret < 0)
                goto err;
@@ -142,14 +144,18 @@ static int cache_block_group(struct btrfs_root *root,
                        break;
                }
 
-               if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
+               if (key.type == BTRFS_EXTENT_ITEM_KEY ||
+                   key.type == BTRFS_METADATA_ITEM_KEY) {
                        if (key.objectid > last) {
                                hole_size = key.objectid - last;
                                set_extent_dirty(free_space_cache, last,
                                                 last + hole_size - 1,
                                                 GFP_NOFS);
                        }
-                       last = key.objectid + key.offset;
+                       if (key.type == BTRFS_METADATA_ITEM_KEY)
+                               last = key.objectid + root->leafsize;
+                       else
+                               last = key.objectid + key.offset;
                }
 next:
                path->slots[0]++;
@@ -239,24 +245,22 @@ static int noinline find_search_start(struct btrfs_root *root,
 {
        int ret;
        struct btrfs_block_group_cache *cache = *cache_ret;
-       u64 last;
+       u64 last = *start_ret;
        u64 start = 0;
        u64 end = 0;
        u64 search_start = *start_ret;
        int wrapped = 0;
 
-       if (!cache) {
+       if (!cache)
                goto out;
-       }
 again:
        ret = cache_block_group(root, cache);
        if (ret)
                goto out;
 
        last = max(search_start, cache->key.objectid);
-       if (cache->ro || !block_group_bits(cache, data)) {
+       if (cache->ro || !block_group_bits(cache, data))
                goto new_group;
-       }
 
        while(1) {
                ret = find_first_extent_bit(&root->fs_info->free_space_cache,
@@ -277,6 +281,7 @@ again:
                return 0;
        }
 out:
+       *start_ret = last;
        cache = btrfs_lookup_block_group(root->fs_info, search_start);
        if (!cache) {
                printk("Unable to find block group for %llu\n",
@@ -290,7 +295,6 @@ new_group:
 wrapped:
        cache = btrfs_lookup_first_block_group(root->fs_info, last);
        if (!cache) {
-no_cache:
                if (!wrapped) {
                        wrapped = 1;
                        last = search_start;
@@ -298,24 +302,10 @@ no_cache:
                }
                goto out;
        }
-       cache = btrfs_find_block_group(root, cache, last, data, 0);
-       cache = btrfs_find_block_group(root, cache, last, data, 0);
-       if (!cache)
-               goto no_cache;
-
        *cache_ret = cache;
        goto again;
 }
 
-static u64 div_factor(u64 num, int factor)
-{
-       if (factor == 10)
-               return num;
-       num *= factor;
-       num /= 10;
-       return num;
-}
-
 static int block_group_state_bits(u64 flags)
 {
        int bits = 0;
@@ -328,10 +318,9 @@ static int block_group_state_bits(u64 flags)
        return bits;
 }
 
-struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
-                                                struct btrfs_block_group_cache
-                                                *hint, u64 search_start,
-                                                int data, int owner)
+static struct btrfs_block_group_cache *
+btrfs_find_block_group(struct btrfs_root *root, struct btrfs_block_group_cache
+                      *hint, u64 search_start, int data, int owner)
 {
        struct btrfs_block_group_cache *cache;
        struct extent_io_tree *block_group_cache;
@@ -435,362 +424,1014 @@ found:
  *    maintenance.  This is actually the same as #2, but with a slightly
  *    different use case.
  *
+ * There are two kinds of back refs. The implicit back refs is optimized
+ * for pointers in non-shared tree blocks. For a given pointer in a block,
+ * back refs of this kind provide information about the block's owner tree
+ * and the pointer's key. These information allow us to find the block by
+ * b-tree searching. The full back refs is for pointers in tree blocks not
+ * referenced by their owner trees. The location of tree block is recorded
+ * in the back refs. Actually the full back refs is generic, and can be
+ * used in all cases the implicit back refs is used. The major shortcoming
+ * of the full back refs is its overhead. Every time a tree block gets
+ * COWed, we have to update back refs entry for all pointers in it.
+ *
+ * For a newly allocated tree block, we use implicit back refs for
+ * pointers in it. This means most tree related operations only involve
+ * implicit back refs. For a tree block created in old transaction, the
+ * only way to drop a reference to it is COW it. So we can detect the
+ * event that tree block loses its owner tree's reference and do the
+ * back refs conversion.
+ *
+ * When a tree block is COW'd through a tree, there are four cases:
+ *
+ * The reference count of the block is one and the tree is the block's
+ * owner tree. Nothing to do in this case.
+ *
+ * The reference count of the block is one and the tree is not the
+ * block's owner tree. In this case, full back refs is used for pointers
+ * in the block. Remove these full back refs, add implicit back refs for
+ * every pointers in the new block.
+ *
+ * The reference count of the block is greater than one and the tree is
+ * the block's owner tree. In this case, implicit back refs is used for
+ * pointers in the block. Add full back refs for every pointers in the
+ * block, increase lower level extents' reference counts. The original
+ * implicit back refs are entailed to the new block.
+ *
+ * The reference count of the block is greater than one and the tree is
+ * not the block's owner tree. Add implicit back refs for every pointer in
+ * the new block, increase lower level extents' reference count.
+ *
+ * Back Reference Key composing:
+ *
+ * The key objectid corresponds to the first byte in the extent,
+ * The key type is used to differentiate between types of back refs.
+ * There are different meanings of the key offset for different types
+ * of back refs.
+ *
  * File extents can be referenced by:
  *
  * - multiple snapshots, subvolumes, or different generations in one subvol
  * - different files inside a single subvolume
  * - different offsets inside a file (bookend extents in file.c)
  *
- * The extent ref structure has fields for:
+ * The extent ref structure for the implicit back refs has fields for:
  *
  * - Objectid of the subvolume root
- * - Generation number of the tree holding the reference
  * - objectid of the file holding the reference
- * - offset in the file corresponding to the key holding the reference
- * - number of references holding by parent node (alway 1 for tree blocks)
- *
- * Btree leaf may hold multiple references to a file extent. In most cases,
- * these references are from same file and the corresponding offsets inside
- * the file are close together. So inode objectid and offset in file are
- * just hints, they provide hints about where in the btree the references
- * can be found and when we can stop searching.
+ * - original offset in the file
+ * - how many bookend extents
  *
- * When a file extent is allocated the fields are filled in:
- *     (root_key.objectid, trans->transid, inode objectid, offset in file, 1)
+ * The key offset for the implicit back refs is hash of the first
+ * three fields.
  *
- * When a leaf is cow'd new references are added for every file extent found
- * in the leaf.  It looks similar to the create case, but trans->transid will
- * be different when the block is cow'd.
+ * The extent ref structure for the full back refs has field for:
  *
- *     (root_key.objectid, trans->transid, inode objectid, offset in file,
- *      number of references in the leaf)
+ * - number of pointers in the tree leaf
  *
- * Because inode objectid and offset in file are just hints, they are not
- * used when backrefs are deleted. When a file extent is removed either
- * during snapshot deletion or file truncation, we find the corresponding
- * back back reference and check the following fields.
+ * The key offset for the implicit back refs is the first byte of
+ * the tree leaf
  *
- *     (btrfs_header_owner(leaf), btrfs_header_generation(leaf))
- *
- * Btree extents can be referenced by:
- *
- * - Different subvolumes
- * - Different generations of the same subvolume
+ * When a file extent is allocated, The implicit back refs is used.
+ * the fields are filled in:
  *
- * When a tree block is created, back references are inserted:
+ *     (root_key.objectid, inode objectid, offset in file, 1)
  *
- * (root->root_key.objectid, trans->transid, level, 0, 1)
+ * When a file extent is removed file truncation, we find the
+ * corresponding implicit back refs and check the following fields:
  *
- * When a tree block is cow'd, new back references are added for all the
- * blocks it points to. If the tree block isn't in reference counted root,
- * the old back references are removed. These new back references are of
- * the form (trans->transid will have increased since creation):
+ *     (btrfs_header_owner(leaf), inode objectid, offset in file)
  *
- * (root->root_key.objectid, trans->transid, level, 0, 1)
- *
- * When a backref is in deleting, the following fields are checked:
+ * Btree extents can be referenced by:
  *
- * if backref was for a tree root:
- *     (btrfs_header_owner(itself), btrfs_header_generation(itself))
- * else
- *     (btrfs_header_owner(parent), btrfs_header_generation(parent))
+ * - Different subvolumes
  *
- * Back Reference Key composing:
+ * Both the implicit back refs and the full back refs for tree blocks
+ * only consist of key. The key offset for the implicit back refs is
+ * objectid of block's owner tree. The key offset for the full back refs
+ * is the first byte of parent block.
  *
- * The key objectid corresponds to the first byte in the extent, the key
- * type is set to BTRFS_EXTENT_REF_KEY, and the key offset is the first
- * byte of parent extent. If a extent is tree root, the key offset is set
- * to the key objectid.
+ * When implicit back refs is used, information about the lowest key and
+ * level of the tree block are required. These information are stored in
+ * tree block info structure.
  */
 
-static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
-                                         struct btrfs_root *root,
-                                         struct btrfs_path *path,
-                                         u64 bytenr, u64 parent,
-                                         u64 ref_root, u64 ref_generation,
-                                         u64 owner_objectid, int del)
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
+                                 struct btrfs_root *root,
+                                 struct btrfs_path *path,
+                                 u64 owner, u32 extra_size)
 {
+       struct btrfs_extent_item *item;
+       struct btrfs_extent_item_v0 *ei0;
+       struct btrfs_extent_ref_v0 *ref0;
+       struct btrfs_tree_block_info *bi;
+       struct extent_buffer *leaf;
        struct btrfs_key key;
-       struct btrfs_extent_ref *ref;
+       struct btrfs_key found_key;
+       u32 new_size = sizeof(*item);
+       u64 refs;
+       int ret;
+
+       leaf = path->nodes[0];
+       BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
+
+       btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+       ei0 = btrfs_item_ptr(leaf, path->slots[0],
+                            struct btrfs_extent_item_v0);
+       refs = btrfs_extent_refs_v0(leaf, ei0);
+
+       if (owner == (u64)-1) {
+               while (1) {
+                       if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+                               ret = btrfs_next_leaf(root, path);
+                               if (ret < 0)
+                                       return ret;
+                               BUG_ON(ret > 0);
+                               leaf = path->nodes[0];
+                       }
+                       btrfs_item_key_to_cpu(leaf, &found_key,
+                                             path->slots[0]);
+                       BUG_ON(key.objectid != found_key.objectid);
+                       if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
+                               path->slots[0]++;
+                               continue;
+                       }
+                       ref0 = btrfs_item_ptr(leaf, path->slots[0],
+                                             struct btrfs_extent_ref_v0);
+                       owner = btrfs_ref_objectid_v0(leaf, ref0);
+                       break;
+               }
+       }
+       btrfs_release_path(path);
+
+       if (owner < BTRFS_FIRST_FREE_OBJECTID)
+               new_size += sizeof(*bi);
+
+       new_size -= sizeof(*ei0);
+       ret = btrfs_search_slot(trans, root, &key, path, new_size, 1);
+       if (ret < 0)
+               return ret;
+       BUG_ON(ret);
+
+       ret = btrfs_extend_item(trans, root, path, new_size);
+       BUG_ON(ret);
+
+       leaf = path->nodes[0];
+       item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+       btrfs_set_extent_refs(leaf, item, refs);
+       /* FIXME: get real generation */
+       btrfs_set_extent_generation(leaf, item, 0);
+       if (owner < BTRFS_FIRST_FREE_OBJECTID) {
+               btrfs_set_extent_flags(leaf, item,
+                                      BTRFS_EXTENT_FLAG_TREE_BLOCK |
+                                      BTRFS_BLOCK_FLAG_FULL_BACKREF);
+               bi = (struct btrfs_tree_block_info *)(item + 1);
+               /* FIXME: get first key of the block */
+               memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
+               btrfs_set_tree_block_level(leaf, bi, (int)owner);
+       } else {
+               btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
+       }
+       btrfs_mark_buffer_dirty(leaf);
+       return 0;
+}
+#endif
+
+static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
+{
+       u32 high_crc = ~(u32)0;
+       u32 low_crc = ~(u32)0;
+       __le64 lenum;
+
+       lenum = cpu_to_le64(root_objectid);
+       high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
+       lenum = cpu_to_le64(owner);
+       low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
+       lenum = cpu_to_le64(offset);
+       low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
+
+       return ((u64)high_crc << 31) ^ (u64)low_crc;
+}
+
+static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
+                                    struct btrfs_extent_data_ref *ref)
+{
+       return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
+                                   btrfs_extent_data_ref_objectid(leaf, ref),
+                                   btrfs_extent_data_ref_offset(leaf, ref));
+}
+
+static int match_extent_data_ref(struct extent_buffer *leaf,
+                                struct btrfs_extent_data_ref *ref,
+                                u64 root_objectid, u64 owner, u64 offset)
+{
+       if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
+           btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
+           btrfs_extent_data_ref_offset(leaf, ref) != offset)
+               return 0;
+       return 1;
+}
+
+static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
+                                          struct btrfs_root *root,
+                                          struct btrfs_path *path,
+                                          u64 bytenr, u64 parent,
+                                          u64 root_objectid,
+                                          u64 owner, u64 offset)
+{
+       struct btrfs_key key;
+       struct btrfs_extent_data_ref *ref;
        struct extent_buffer *leaf;
-       u64 ref_objectid;
+       u32 nritems;
        int ret;
+       int recow;
+       int err = -ENOENT;
 
        key.objectid = bytenr;
-       key.type = BTRFS_EXTENT_REF_KEY;
-       key.offset = parent;
+       if (parent) {
+               key.type = BTRFS_SHARED_DATA_REF_KEY;
+               key.offset = parent;
+       } else {
+               key.type = BTRFS_EXTENT_DATA_REF_KEY;
+               key.offset = hash_extent_data_ref(root_objectid,
+                                                 owner, offset);
+       }
+again:
+       recow = 0;
+       ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+       if (ret < 0) {
+               err = ret;
+               goto fail;
+       }
 
-       ret = btrfs_search_slot(trans, root, &key, path, del ? -1 : 0, 1);
-       if (ret < 0)
-               goto out;
-       if (ret > 0) {
-               ret = -ENOENT;
-               goto out;
+       if (parent) {
+               if (!ret)
+                       return 0;
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+               key.type = BTRFS_EXTENT_REF_V0_KEY;
+               btrfs_release_path(path);
+               ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+               if (ret < 0) {
+                       err = ret;
+                       goto fail;
+               }
+               if (!ret)
+                       return 0;
+#endif
+               goto fail;
        }
 
        leaf = path->nodes[0];
-       ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
-       ref_objectid = btrfs_ref_objectid(leaf, ref);
-       if (btrfs_ref_root(leaf, ref) != ref_root ||
-           btrfs_ref_generation(leaf, ref) != ref_generation ||
-           (ref_objectid != owner_objectid &&
-            ref_objectid != BTRFS_MULTIPLE_OBJECTIDS)) {
-               ret = -EIO;
-               WARN_ON(1);
-               goto out;
+       nritems = btrfs_header_nritems(leaf);
+       while (1) {
+               if (path->slots[0] >= nritems) {
+                       ret = btrfs_next_leaf(root, path);
+                       if (ret < 0)
+                               err = ret;
+                       if (ret)
+                               goto fail;
+
+                       leaf = path->nodes[0];
+                       nritems = btrfs_header_nritems(leaf);
+                       recow = 1;
+               }
+
+               btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+               if (key.objectid != bytenr ||
+                   key.type != BTRFS_EXTENT_DATA_REF_KEY)
+                       goto fail;
+               
+               ref = btrfs_item_ptr(leaf, path->slots[0],
+                                    struct btrfs_extent_data_ref);
+
+               if (match_extent_data_ref(leaf, ref, root_objectid,
+                                         owner, offset)) {
+                       if (recow) {
+                               btrfs_release_path(path);
+                               goto again;
+                       }
+                       err = 0;
+                       break;
+               }
+               path->slots[0]++;
        }
-       ret = 0;
-out:
-       return ret;
+fail:
+       return err;
 }
 
-static int noinline insert_extent_backref(struct btrfs_trans_handle *trans,
-                                         struct btrfs_root *root,
-                                         struct btrfs_path *path,
-                                         u64 bytenr, u64 parent,
-                                         u64 ref_root, u64 ref_generation,
-                                         u64 owner_objectid)
+static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
+                                          struct btrfs_root *root,
+                                          struct btrfs_path *path,
+                                          u64 bytenr, u64 parent,
+                                          u64 root_objectid, u64 owner,
+                                          u64 offset, int refs_to_add)
 {
        struct btrfs_key key;
        struct extent_buffer *leaf;
-       struct btrfs_extent_ref *ref;
+       u32 size;
        u32 num_refs;
        int ret;
 
        key.objectid = bytenr;
-       key.type = BTRFS_EXTENT_REF_KEY;
-       key.offset = parent;
+       if (parent) {
+               key.type = BTRFS_SHARED_DATA_REF_KEY;
+               key.offset = parent;
+               size = sizeof(struct btrfs_shared_data_ref);
+       } else {
+               key.type = BTRFS_EXTENT_DATA_REF_KEY;
+               key.offset = hash_extent_data_ref(root_objectid,
+                                                 owner, offset);
+               size = sizeof(struct btrfs_extent_data_ref);
+       }
 
-       ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*ref));
-       if (ret == 0) {
-               leaf = path->nodes[0];
-               ref = btrfs_item_ptr(leaf, path->slots[0],
-                                    struct btrfs_extent_ref);
-               btrfs_set_ref_root(leaf, ref, ref_root);
-               btrfs_set_ref_generation(leaf, ref, ref_generation);
-               btrfs_set_ref_objectid(leaf, ref, owner_objectid);
-               btrfs_set_ref_num_refs(leaf, ref, 1);
-       } else if (ret == -EEXIST) {
-               u64 existing_owner;
-               BUG_ON(owner_objectid < BTRFS_FIRST_FREE_OBJECTID);
-               leaf = path->nodes[0];
+       ret = btrfs_insert_empty_item(trans, root, path, &key, size);
+       if (ret && ret != -EEXIST)
+               goto fail;
+
+       leaf = path->nodes[0];
+       if (parent) {
+               struct btrfs_shared_data_ref *ref;
                ref = btrfs_item_ptr(leaf, path->slots[0],
-                                    struct btrfs_extent_ref);
-               if (btrfs_ref_root(leaf, ref) != ref_root ||
-                   btrfs_ref_generation(leaf, ref) != ref_generation) {
-                       ret = -EIO;
-                       WARN_ON(1);
-                       goto out;
+                                    struct btrfs_shared_data_ref);
+               if (ret == 0) {
+                       btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
+               } else {
+                       num_refs = btrfs_shared_data_ref_count(leaf, ref);
+                       num_refs += refs_to_add;
+                       btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
                }
+       } else {
+               struct btrfs_extent_data_ref *ref;
+               while (ret == -EEXIST) {
+                       ref = btrfs_item_ptr(leaf, path->slots[0],
+                                            struct btrfs_extent_data_ref);
+                       if (match_extent_data_ref(leaf, ref, root_objectid,
+                                                 owner, offset))
+                               break;
+                       btrfs_release_path(path);
 
-               num_refs = btrfs_ref_num_refs(leaf, ref);
-               BUG_ON(num_refs == 0);
-               btrfs_set_ref_num_refs(leaf, ref, num_refs + 1);
+                       key.offset++;
+                       ret = btrfs_insert_empty_item(trans, root, path, &key,
+                                                     size);
+                       if (ret && ret != -EEXIST)
+                               goto fail;
 
-               existing_owner = btrfs_ref_objectid(leaf, ref);
-               if (existing_owner != owner_objectid &&
-                   existing_owner != BTRFS_MULTIPLE_OBJECTIDS) {
-                       btrfs_set_ref_objectid(leaf, ref,
-                                       BTRFS_MULTIPLE_OBJECTIDS);
+                       leaf = path->nodes[0];
+               }
+               ref = btrfs_item_ptr(leaf, path->slots[0],
+                                    struct btrfs_extent_data_ref);
+               if (ret == 0) {
+                       btrfs_set_extent_data_ref_root(leaf, ref,
+                                                      root_objectid);
+                       btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
+                       btrfs_set_extent_data_ref_offset(leaf, ref, offset);
+                       btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
+               } else {
+                       num_refs = btrfs_extent_data_ref_count(leaf, ref);
+                       num_refs += refs_to_add;
+                       btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
                }
-               ret = 0;
-       } else {
-               goto out;
        }
-       btrfs_mark_buffer_dirty(path->nodes[0]);
-out:
-       btrfs_release_path(root, path);
+       btrfs_mark_buffer_dirty(leaf);
+       ret = 0;
+fail:
+       btrfs_release_path(path);
        return ret;
 }
 
-static int noinline remove_extent_backref(struct btrfs_trans_handle *trans,
-                                         struct btrfs_root *root,
-                                         struct btrfs_path *path)
+static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
+                                          struct btrfs_root *root,
+                                          struct btrfs_path *path,
+                                          int refs_to_drop)
 {
+       struct btrfs_key key;
+       struct btrfs_extent_data_ref *ref1 = NULL;
+       struct btrfs_shared_data_ref *ref2 = NULL;
        struct extent_buffer *leaf;
-       struct btrfs_extent_ref *ref;
-       u32 num_refs;
+       u32 num_refs = 0;
        int ret = 0;
 
        leaf = path->nodes[0];
-       ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
-       num_refs = btrfs_ref_num_refs(leaf, ref);
-       BUG_ON(num_refs == 0);
-       num_refs -= 1;
+       btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+
+       if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
+               ref1 = btrfs_item_ptr(leaf, path->slots[0],
+                                     struct btrfs_extent_data_ref);
+               num_refs = btrfs_extent_data_ref_count(leaf, ref1);
+       } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
+               ref2 = btrfs_item_ptr(leaf, path->slots[0],
+                                     struct btrfs_shared_data_ref);
+               num_refs = btrfs_shared_data_ref_count(leaf, ref2);
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+       } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
+               struct btrfs_extent_ref_v0 *ref0;
+               ref0 = btrfs_item_ptr(leaf, path->slots[0],
+                                     struct btrfs_extent_ref_v0);
+               num_refs = btrfs_ref_count_v0(leaf, ref0);
+#endif
+       } else {
+               BUG();
+       }
+
+       BUG_ON(num_refs < refs_to_drop);
+       num_refs -= refs_to_drop;
+
        if (num_refs == 0) {
                ret = btrfs_del_item(trans, root, path);
        } else {
-               btrfs_set_ref_num_refs(leaf, ref, num_refs);
+               if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
+                       btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
+               else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
+                       btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+               else {
+                       struct btrfs_extent_ref_v0 *ref0;
+                       ref0 = btrfs_item_ptr(leaf, path->slots[0],
+                                       struct btrfs_extent_ref_v0);
+                       btrfs_set_ref_count_v0(leaf, ref0, num_refs);
+               }
+#endif
                btrfs_mark_buffer_dirty(leaf);
        }
-       btrfs_release_path(root, path);
        return ret;
 }
 
-static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
-                                    struct btrfs_root *root, u64 bytenr,
-                                    u64 orig_parent, u64 parent,
-                                    u64 orig_root, u64 ref_root,
-                                    u64 orig_generation, u64 ref_generation,
-                                    u64 owner_objectid)
+static noinline u32 extent_data_ref_count(struct btrfs_root *root,
+                                         struct btrfs_path *path,
+                                         struct btrfs_extent_inline_ref *iref)
 {
-       int ret;
-       struct btrfs_root *extent_root = root->fs_info->extent_root;
-       struct btrfs_path *path;
+       struct btrfs_key key;
+       struct extent_buffer *leaf;
+       struct btrfs_extent_data_ref *ref1;
+       struct btrfs_shared_data_ref *ref2;
+       u32 num_refs = 0;
 
-       if (root == root->fs_info->extent_root) {
-               struct pending_extent_op *extent_op;
-               u64 num_bytes;
-
-               BUG_ON(owner_objectid >= BTRFS_MAX_LEVEL);
-               num_bytes = btrfs_level_size(root, (int)owner_objectid);
-               if (test_range_bit(&root->fs_info->extent_ins, bytenr,
-                               bytenr + num_bytes - 1, EXTENT_LOCKED, 0)) {
-                       u64 priv;
-                       ret = get_state_private(&root->fs_info->extent_ins,
-                                               bytenr, &priv);
-                       BUG_ON(ret);
-                       extent_op = (struct pending_extent_op *)
-                                                       (unsigned long)priv;
-                       BUG_ON(extent_op->parent != orig_parent);
-                       BUG_ON(extent_op->generation != orig_generation);
-                       extent_op->parent = parent;
-                       extent_op->generation = ref_generation;
+       leaf = path->nodes[0];
+       btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+       if (iref) {
+               if (btrfs_extent_inline_ref_type(leaf, iref) ==
+                   BTRFS_EXTENT_DATA_REF_KEY) {
+                       ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
+                       num_refs = btrfs_extent_data_ref_count(leaf, ref1);
                } else {
-                       extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
-                       BUG_ON(!extent_op);
-
-                       extent_op->type = PENDING_BACKREF_UPDATE;
-                       extent_op->bytenr = bytenr;
-                       extent_op->num_bytes = num_bytes;
-                       extent_op->parent = parent;
-                       extent_op->orig_parent = orig_parent;
-                       extent_op->generation = ref_generation;
-                       extent_op->orig_generation = orig_generation;
-                       extent_op->level = (int)owner_objectid;
-
-                       set_extent_bits(&root->fs_info->extent_ins,
-                                       bytenr, bytenr + num_bytes - 1,
-                                       EXTENT_LOCKED, GFP_NOFS);
-                       set_state_private(&root->fs_info->extent_ins,
-                                         bytenr, (unsigned long)extent_op);
+                       ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
+                       num_refs = btrfs_shared_data_ref_count(leaf, ref2);
                }
-               return 0;
+       } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
+               ref1 = btrfs_item_ptr(leaf, path->slots[0],
+                                     struct btrfs_extent_data_ref);
+               num_refs = btrfs_extent_data_ref_count(leaf, ref1);
+       } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
+               ref2 = btrfs_item_ptr(leaf, path->slots[0],
+                                     struct btrfs_shared_data_ref);
+               num_refs = btrfs_shared_data_ref_count(leaf, ref2);
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+       } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
+               struct btrfs_extent_ref_v0 *ref0;
+               ref0 = btrfs_item_ptr(leaf, path->slots[0],
+                                     struct btrfs_extent_ref_v0);
+               num_refs = btrfs_ref_count_v0(leaf, ref0);
+#endif
+       } else {
+               BUG();
        }
+       return num_refs;
+}
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-       ret = lookup_extent_backref(trans, extent_root, path,
-                                   bytenr, orig_parent, orig_root,
-                                   orig_generation, owner_objectid, 1);
-       if (ret)
-               goto out;
-       ret = remove_extent_backref(trans, extent_root, path);
-       if (ret)
-               goto out;
-       ret = insert_extent_backref(trans, extent_root, path, bytenr,
-                                   parent, ref_root, ref_generation,
-                                   owner_objectid);
-       BUG_ON(ret);
-       finish_current_insert(trans, extent_root);
-       del_pending_extents(trans, extent_root);
-out:
-       btrfs_free_path(path);
+static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
+                                         struct btrfs_root *root,
+                                         struct btrfs_path *path,
+                                         u64 bytenr, u64 parent,
+                                         u64 root_objectid)
+{
+       struct btrfs_key key;
+       int ret;
+
+       key.objectid = bytenr;
+       if (parent) {
+               key.type = BTRFS_SHARED_BLOCK_REF_KEY;
+               key.offset = parent;
+       } else {
+               key.type = BTRFS_TREE_BLOCK_REF_KEY;
+               key.offset = root_objectid;
+       }
+
+       ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+       if (ret > 0)
+               ret = -ENOENT;
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+       if (ret == -ENOENT && parent) {
+               btrfs_release_path(path);
+               key.type = BTRFS_EXTENT_REF_V0_KEY;
+               ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+               if (ret > 0)
+                       ret = -ENOENT;
+       }
+#endif
        return ret;
 }
 
-int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
-                           struct btrfs_root *root, u64 bytenr,
-                           u64 orig_parent, u64 parent,
-                           u64 ref_root, u64 ref_generation,
-                           u64 owner_objectid)
+static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
+                                         struct btrfs_root *root,
+                                         struct btrfs_path *path,
+                                         u64 bytenr, u64 parent,
+                                         u64 root_objectid)
 {
+       struct btrfs_key key;
        int ret;
-       if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
-           owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
-               return 0;
-       maybe_lock_mutex(root);
-       ret = __btrfs_update_extent_ref(trans, root, bytenr, orig_parent,
-                                       parent, ref_root, ref_root,
-                                       ref_generation, ref_generation,
-                                       owner_objectid);
-       maybe_unlock_mutex(root);
+
+       key.objectid = bytenr;
+       if (parent) {
+               key.type = BTRFS_SHARED_BLOCK_REF_KEY;
+               key.offset = parent;
+       } else {
+               key.type = BTRFS_TREE_BLOCK_REF_KEY;
+               key.offset = root_objectid;
+       }
+
+       ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
+
+       btrfs_release_path(path);
        return ret;
 }
 
-static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
-                                 struct btrfs_root *root, u64 bytenr,
-                                 u64 orig_parent, u64 parent,
-                                 u64 orig_root, u64 ref_root,
-                                 u64 orig_generation, u64 ref_generation,
-                                 u64 owner_objectid)
+static inline int extent_ref_type(u64 parent, u64 owner)
 {
-       struct btrfs_path *path;
-       int ret;
-       struct btrfs_key key;
-       struct extent_buffer *l;
-       struct btrfs_extent_item *item;
-       u32 refs;
+       int type;
+       if (owner < BTRFS_FIRST_FREE_OBJECTID) {
+               if (parent > 0)
+                       type = BTRFS_SHARED_BLOCK_REF_KEY;
+               else
+                       type = BTRFS_TREE_BLOCK_REF_KEY;
+       } else {
+               if (parent > 0)
+                       type = BTRFS_SHARED_DATA_REF_KEY;
+               else
+                       type = BTRFS_EXTENT_DATA_REF_KEY;
+       }
+       return type;
+}
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
+static int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
+                                struct btrfs_root *root,
+                                struct btrfs_path *path,
+                                struct btrfs_extent_inline_ref **ref_ret,
+                                u64 bytenr, u64 num_bytes,
+                                u64 parent, u64 root_objectid,
+                                u64 owner, u64 offset, int insert)
+{
+       struct btrfs_key key;
+       struct extent_buffer *leaf;
+       struct btrfs_extent_item *ei;
+       struct btrfs_extent_inline_ref *iref;
+       u64 flags;
+       u32 item_size;
+       unsigned long ptr;
+       unsigned long end;
+       int extra_size;
+       int type;
+       int want;
+       int ret;
+       int err = 0;
+       int skinny_metadata =
+               btrfs_fs_incompat(root->fs_info,
+                                 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
 
-       path->reada = 1;
        key.objectid = bytenr;
        key.type = BTRFS_EXTENT_ITEM_KEY;
-       key.offset = (u64)-1;
+       key.offset = num_bytes;
 
-       ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
-                               0, 1);
-       if (ret < 0)
-               return ret;
-       BUG_ON(ret == 0 || path->slots[0] == 0);
+       want = extent_ref_type(parent, owner);
+       if (insert)
+               extra_size = btrfs_extent_inline_ref_size(want);
+       else
+               extra_size = -1;
 
-       path->slots[0]--;
-       l = path->nodes[0];
+       if (owner < BTRFS_FIRST_FREE_OBJECTID && skinny_metadata) {
+               skinny_metadata = 1;
+               key.type = BTRFS_METADATA_ITEM_KEY;
+               key.offset = owner;
+       } else if (skinny_metadata) {
+               skinny_metadata = 0;
+       }
 
-       btrfs_item_key_to_cpu(l, &key, path->slots[0]);
-       BUG_ON(key.objectid != bytenr);
-       BUG_ON(key.type != BTRFS_EXTENT_ITEM_KEY);
+again:
+       ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
+       if (ret < 0) {
+               err = ret;
+               goto out;
+       }
 
-       item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
-       refs = btrfs_extent_refs(l, item);
-       btrfs_set_extent_refs(l, item, refs + 1);
-       btrfs_mark_buffer_dirty(path->nodes[0]);
+       /*
+        * We may be a newly converted file system which still has the old fat
+        * extent entries for metadata, so try and see if we have one of those.
+        */
+       if (ret > 0 && skinny_metadata) {
+               skinny_metadata = 0;
+               if (path->slots[0]) {
+                       path->slots[0]--;
+                       btrfs_item_key_to_cpu(path->nodes[0], &key,
+                                             path->slots[0]);
+                       if (key.objectid == bytenr &&
+                           key.type == BTRFS_EXTENT_ITEM_KEY &&
+                           key.offset == num_bytes)
+                               ret = 0;
+               }
+               if (ret) {
+                       key.type = BTRFS_EXTENT_ITEM_KEY;
+                       key.offset = num_bytes;
+                       btrfs_release_path(path);
+                       goto again;
+               }
+       }
 
-       btrfs_release_path(root->fs_info->extent_root, path);
+       if (ret) {
+               printf("Failed to find [%llu, %u, %llu]\n", key.objectid, key.type, key.offset);
+               return -ENOENT;
+       }
 
-       path->reada = 1;
-       ret = insert_extent_backref(trans, root->fs_info->extent_root,
-                                   path, bytenr, parent,
-                                   ref_root, ref_generation,
-                                   owner_objectid);
        BUG_ON(ret);
-       finish_current_insert(trans, root->fs_info->extent_root);
-       del_pending_extents(trans, root->fs_info->extent_root);
 
-       btrfs_free_path(path);
+       leaf = path->nodes[0];
+       item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+       if (item_size < sizeof(*ei)) {
+               if (!insert) {
+                       err = -ENOENT;
+                       goto out;
+               }
+               ret = convert_extent_item_v0(trans, root, path, owner,
+                                            extra_size);
+               if (ret < 0) {
+                       err = ret;
+                       goto out;
+               }
+               leaf = path->nodes[0];
+               item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+       }
+#endif
+       if (item_size < sizeof(*ei)) {
+               printf("Size is %u, needs to be %u, slot %d\n",
+                      (unsigned)item_size,
+                      (unsigned)sizeof(*ei), path->slots[0]);
+               btrfs_print_leaf(root, leaf);
+               return -EINVAL;
+       }
+       BUG_ON(item_size < sizeof(*ei));
+
+       ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+       flags = btrfs_extent_flags(leaf, ei);
+
+       ptr = (unsigned long)(ei + 1);
+       end = (unsigned long)ei + item_size;
+
+       if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
+               ptr += sizeof(struct btrfs_tree_block_info);
+               BUG_ON(ptr > end);
+       } else if (!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
+               if (!(flags & BTRFS_EXTENT_FLAG_DATA)) {
+                       return -EIO;
+               }
+       }
+
+       err = -ENOENT;
+       while (1) {
+               if (ptr >= end) {
+                       WARN_ON(ptr > end);
+                       break;
+               }
+               iref = (struct btrfs_extent_inline_ref *)ptr;
+               type = btrfs_extent_inline_ref_type(leaf, iref);
+               if (want < type)
+                       break;
+               if (want > type) {
+                       ptr += btrfs_extent_inline_ref_size(type);
+                       continue;
+               }
+
+               if (type == BTRFS_EXTENT_DATA_REF_KEY) {
+                       struct btrfs_extent_data_ref *dref;
+                       dref = (struct btrfs_extent_data_ref *)(&iref->offset);
+                       if (match_extent_data_ref(leaf, dref, root_objectid,
+                                                 owner, offset)) {
+                               err = 0;
+                               break;
+                       }
+                       if (hash_extent_data_ref_item(leaf, dref) <
+                           hash_extent_data_ref(root_objectid, owner, offset))
+                               break;
+               } else {
+                       u64 ref_offset;
+                       ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
+                       if (parent > 0) {
+                               if (parent == ref_offset) {
+                                       err = 0;
+                                       break;
+                               }
+                               if (ref_offset < parent)
+                                       break;
+                       } else {
+                               if (root_objectid == ref_offset) {
+                                       err = 0;
+                                       break;
+                               }
+                               if (ref_offset < root_objectid)
+                                       break;
+                       }
+               }
+               ptr += btrfs_extent_inline_ref_size(type);
+       }
+       if (err == -ENOENT && insert) {
+               if (item_size + extra_size >=
+                   BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
+                       err = -EAGAIN;
+                       goto out;
+               }
+               /*
+                * To add new inline back ref, we have to make sure
+                * there is no corresponding back ref item.
+                * For simplicity, we just do not add new inline back
+                * ref if there is any back ref item.
+                */
+               if (find_next_key(path, &key) == 0 && key.objectid == bytenr &&
+                   key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
+                       err = -EAGAIN;
+                       goto out;
+               }
+       }
+       *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
+out:
+       return err;
+}
+
+static int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
+                               struct btrfs_root *root,
+                               struct btrfs_path *path,
+                               struct btrfs_extent_inline_ref *iref,
+                               u64 parent, u64 root_objectid,
+                               u64 owner, u64 offset, int refs_to_add)
+{
+       struct extent_buffer *leaf;
+       struct btrfs_extent_item *ei;
+       unsigned long ptr;
+       unsigned long end;
+       unsigned long item_offset;
+       u64 refs;
+       int size;
+       int type;
+       int ret;
+
+       leaf = path->nodes[0];
+       ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+       item_offset = (unsigned long)iref - (unsigned long)ei;
+
+       type = extent_ref_type(parent, owner);
+       size = btrfs_extent_inline_ref_size(type);
+
+       ret = btrfs_extend_item(trans, root, path, size);
+       BUG_ON(ret);
+
+       ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+       refs = btrfs_extent_refs(leaf, ei);
+       refs += refs_to_add;
+       btrfs_set_extent_refs(leaf, ei, refs);
+
+       ptr = (unsigned long)ei + item_offset;
+       end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
+       if (ptr < end - size)
+               memmove_extent_buffer(leaf, ptr + size, ptr,
+                                     end - size - ptr);
+
+       iref = (struct btrfs_extent_inline_ref *)ptr;
+       btrfs_set_extent_inline_ref_type(leaf, iref, type);
+       if (type == BTRFS_EXTENT_DATA_REF_KEY) {
+               struct btrfs_extent_data_ref *dref;
+               dref = (struct btrfs_extent_data_ref *)(&iref->offset);
+               btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
+               btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
+               btrfs_set_extent_data_ref_offset(leaf, dref, offset);
+               btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
+       } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
+               struct btrfs_shared_data_ref *sref;
+               sref = (struct btrfs_shared_data_ref *)(iref + 1);
+               btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
+               btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
+       } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
+               btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
+       } else {
+               btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
+       }
+       btrfs_mark_buffer_dirty(leaf);
+       return 0;
+}
+
+static int lookup_extent_backref(struct btrfs_trans_handle *trans,
+                                struct btrfs_root *root,
+                                struct btrfs_path *path,
+                                struct btrfs_extent_inline_ref **ref_ret,
+                                u64 bytenr, u64 num_bytes, u64 parent,
+                                u64 root_objectid, u64 owner, u64 offset)
+{
+       int ret;
+
+       ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
+                                          bytenr, num_bytes, parent,
+                                          root_objectid, owner, offset, 0);
+       if (ret != -ENOENT)
+               return ret;
+
+       btrfs_release_path(path);
+       *ref_ret = NULL;
+
+       if (owner < BTRFS_FIRST_FREE_OBJECTID) {
+               ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
+                                           root_objectid);
+       } else {
+               ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
+                                            root_objectid, owner, offset);
+       }
+       return ret;
+}
+
+static int update_inline_extent_backref(struct btrfs_trans_handle *trans,
+                                struct btrfs_root *root,
+                                struct btrfs_path *path,
+                                struct btrfs_extent_inline_ref *iref,
+                                int refs_to_mod)
+{
+       struct extent_buffer *leaf;
+       struct btrfs_extent_item *ei;
+       struct btrfs_extent_data_ref *dref = NULL;
+       struct btrfs_shared_data_ref *sref = NULL;
+       unsigned long ptr;
+       unsigned long end;
+       u32 item_size;
+       int size;
+       int type;
+       int ret;
+       u64 refs;
+
+       leaf = path->nodes[0];
+       ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+       refs = btrfs_extent_refs(leaf, ei);
+       WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
+       refs += refs_to_mod;
+       btrfs_set_extent_refs(leaf, ei, refs);
+
+       type = btrfs_extent_inline_ref_type(leaf, iref);
+
+       if (type == BTRFS_EXTENT_DATA_REF_KEY) {
+               dref = (struct btrfs_extent_data_ref *)(&iref->offset);
+               refs = btrfs_extent_data_ref_count(leaf, dref);
+       } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
+               sref = (struct btrfs_shared_data_ref *)(iref + 1);
+               refs = btrfs_shared_data_ref_count(leaf, sref);
+       } else {
+               refs = 1;
+               BUG_ON(refs_to_mod != -1);
+       }
+
+       BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
+       refs += refs_to_mod;
+
+       if (refs > 0) {
+               if (type == BTRFS_EXTENT_DATA_REF_KEY)
+                       btrfs_set_extent_data_ref_count(leaf, dref, refs);
+               else
+                       btrfs_set_shared_data_ref_count(leaf, sref, refs);
+       } else {
+               size =  btrfs_extent_inline_ref_size(type);
+               item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+               ptr = (unsigned long)iref;
+               end = (unsigned long)ei + item_size;
+               if (ptr + size < end)
+                       memmove_extent_buffer(leaf, ptr, ptr + size,
+                                             end - ptr - size);
+               item_size -= size;
+               ret = btrfs_truncate_item(trans, root, path, item_size, 1);
+               BUG_ON(ret);
+       }
+       btrfs_mark_buffer_dirty(leaf);
        return 0;
 }
 
+static int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
+                                struct btrfs_root *root,
+                                struct btrfs_path *path,
+                                u64 bytenr, u64 num_bytes, u64 parent,
+                                u64 root_objectid, u64 owner,
+                                u64 offset, int refs_to_add)
+{
+       struct btrfs_extent_inline_ref *iref;
+       int ret;
+
+       ret = lookup_inline_extent_backref(trans, root, path, &iref,
+                                          bytenr, num_bytes, parent,
+                                          root_objectid, owner, offset, 1);
+       if (ret == 0) {
+               BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
+               ret = update_inline_extent_backref(trans, root, path, iref,
+                                                  refs_to_add);
+       } else if (ret == -ENOENT) {
+               ret = setup_inline_extent_backref(trans, root, path, iref,
+                                                 parent, root_objectid,
+                                                 owner, offset, refs_to_add);
+       }
+       return ret;
+}
+
+static int insert_extent_backref(struct btrfs_trans_handle *trans,
+                                struct btrfs_root *root,
+                                struct btrfs_path *path,
+                                u64 bytenr, u64 parent, u64 root_objectid,
+                                u64 owner, u64 offset, int refs_to_add)
+{
+       int ret;
+
+       if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
+               ret = insert_extent_data_ref(trans, root, path, bytenr,
+                                            parent, root_objectid,
+                                            owner, offset, refs_to_add);
+       } else {
+               BUG_ON(refs_to_add != 1);
+               ret = insert_tree_block_ref(trans, root, path, bytenr,
+                                           parent, root_objectid);
+       }
+       return ret;
+}
+
+static int remove_extent_backref(struct btrfs_trans_handle *trans,
+                                struct btrfs_root *root,
+                                struct btrfs_path *path,
+                                struct btrfs_extent_inline_ref *iref,
+                                int refs_to_drop, int is_data)
+{
+       int ret;
+
+       BUG_ON(!is_data && refs_to_drop != 1);
+       if (iref) {
+               ret = update_inline_extent_backref(trans, root, path, iref,
+                                                  -refs_to_drop);
+       } else if (is_data) {
+               ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
+       } else {
+               ret = btrfs_del_item(trans, root, path);
+       }
+       return ret;
+}
+
 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
                         struct btrfs_root *root,
                         u64 bytenr, u64 num_bytes, u64 parent,
-                        u64 ref_root, u64 ref_generation,
-                        u64 owner_objectid)
+                        u64 root_objectid, u64 owner, u64 offset)
 {
+       struct btrfs_path *path;
+       struct extent_buffer *leaf;
+       struct btrfs_extent_item *item;
+       u64 refs;
        int ret;
-       if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
-           owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
-               return 0;
-       maybe_lock_mutex(root);
-       ret = __btrfs_inc_extent_ref(trans, root, bytenr, 0, parent,
-                                    0, ref_root, 0, ref_generation,
-                                    owner_objectid);
-       maybe_unlock_mutex(root);
-       return ret;
+       int err = 0;
+
+       path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
+
+       path->reada = 1;
+
+       ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
+                                          path, bytenr, num_bytes, parent,
+                                          root_objectid, owner, offset, 1);
+       if (ret == 0)
+               goto out;
+
+       if (ret != -EAGAIN) {
+               err = ret;
+               goto out;
+       }
+       
+       leaf = path->nodes[0];
+       item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+       refs = btrfs_extent_refs(leaf, item);
+       btrfs_set_extent_refs(leaf, item, refs + 1);
+
+       btrfs_mark_buffer_dirty(leaf);
+       btrfs_release_path(path);
+
+       path->reada = 1;
+
+       /* now insert the actual backref */
+       ret = insert_extent_backref(trans, root->fs_info->extent_root,
+                                   path, bytenr, parent, root_objectid,
+                                   owner, offset, 1);
+       if (ret)
+               err = ret;
+out:
+       btrfs_free_path(path);
+       finish_current_insert(trans, root->fs_info->extent_root);
+       del_pending_extents(trans, root->fs_info->extent_root);
+       BUG_ON(err);
+       return err;
 }
 
 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
@@ -801,26 +1442,158 @@ int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
        return 0;
 }
 
-int btrfs_lookup_extent_ref(struct btrfs_trans_handle *trans,
-                           struct btrfs_root *root, u64 bytenr,
-                           u64 num_bytes, u32 *refs)
+int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
+                            struct btrfs_root *root, u64 bytenr,
+                            u64 offset, int metadata, u64 *refs, u64 *flags)
 {
        struct btrfs_path *path;
        int ret;
        struct btrfs_key key;
        struct extent_buffer *l;
        struct btrfs_extent_item *item;
+       u32 item_size;
+       u64 num_refs;
+       u64 extent_flags;
+
+       if (metadata &&
+           !btrfs_fs_incompat(root->fs_info,
+                              BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)) {
+               offset = root->leafsize;
+               metadata = 0;
+       }
 
-       WARN_ON(num_bytes < root->sectorsize);
        path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
        path->reada = 1;
+
        key.objectid = bytenr;
-       key.offset = num_bytes;
-       btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
+       key.offset = offset;
+       if (metadata)
+               key.type = BTRFS_METADATA_ITEM_KEY;
+       else
+               key.type = BTRFS_EXTENT_ITEM_KEY;
+
+again:
+       ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
+                               0, 0);
+       if (ret < 0)
+               goto out;
+
+       /*
+        * Deal with the fact that we may have mixed SKINNY and normal refs.  If
+        * we didn't find what we wanted check and see if we have a normal ref
+        * right next to us, or re-search if we are on the edge of the leaf just
+        * to make sure.
+        */
+       if (ret > 0 && metadata) {
+               if (path->slots[0]) {
+                       path->slots[0]--;
+                       btrfs_item_key_to_cpu(path->nodes[0], &key,
+                                             path->slots[0]);
+                       if (key.objectid == bytenr &&
+                           key.type == BTRFS_EXTENT_ITEM_KEY &&
+                           key.offset == root->leafsize)
+                               ret = 0;
+               }
+
+               if (ret) {
+                       btrfs_release_path(path);
+                       key.type = BTRFS_EXTENT_ITEM_KEY;
+                       key.offset = root->leafsize;
+                       metadata = 0;
+                       goto again;
+               }
+       }
+
+       if (ret != 0) {
+               ret = -EIO;
+               goto out;
+       }
+
+       l = path->nodes[0];
+       item_size = btrfs_item_size_nr(l, path->slots[0]);
+       if (item_size >= sizeof(*item)) {
+               item = btrfs_item_ptr(l, path->slots[0],
+                                     struct btrfs_extent_item);
+               num_refs = btrfs_extent_refs(l, item);
+               extent_flags = btrfs_extent_flags(l, item);
+       } else {
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+                       struct btrfs_extent_item_v0 *ei0;
+                       BUG_ON(item_size != sizeof(*ei0));
+                       ei0 = btrfs_item_ptr(l, path->slots[0],
+                                            struct btrfs_extent_item_v0);
+                       num_refs = btrfs_extent_refs_v0(l, ei0);
+                       /* FIXME: this isn't correct for data */
+                       extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
+#else
+                       BUG();
+#endif
+       }
+       item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
+       if (refs)
+               *refs = num_refs;
+       if (flags)
+               *flags = extent_flags;
+out:
+       btrfs_free_path(path);
+       return ret;
+}
+
+int btrfs_set_block_flags(struct btrfs_trans_handle *trans,
+                         struct btrfs_root *root,
+                         u64 bytenr, int level, u64 flags)
+{
+       struct btrfs_path *path;
+       int ret;
+       struct btrfs_key key;
+       struct extent_buffer *l;
+       struct btrfs_extent_item *item;
+       u32 item_size;
+       int skinny_metadata =
+               btrfs_fs_incompat(root->fs_info,
+                                 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
+
+       path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
+       path->reada = 1;
+
+       key.objectid = bytenr;
+       if (skinny_metadata) {
+               key.offset = level;
+               key.type = BTRFS_METADATA_ITEM_KEY;
+       } else {
+               key.offset = root->leafsize;
+               key.type = BTRFS_EXTENT_ITEM_KEY;
+       }
+
+again:
        ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
                                0, 0);
        if (ret < 0)
                goto out;
+
+       if (ret > 0 && skinny_metadata) {
+               skinny_metadata = 0;
+               if (path->slots[0]) {
+                       path->slots[0]--;
+                       btrfs_item_key_to_cpu(path->nodes[0], &key,
+                                             path->slots[0]);
+                       if (key.objectid == bytenr &&
+                           key.offset == root->leafsize &&
+                           key.type == BTRFS_EXTENT_ITEM_KEY)
+                               ret = 0;
+               }
+               if (ret) {
+                       btrfs_release_path(path);
+                       key.offset = root->leafsize;
+                       key.type = BTRFS_EXTENT_ITEM_KEY;
+                       goto again;
+               }
+       }
+
        if (ret != 0) {
                btrfs_print_leaf(root, path->nodes[0]);
                printk("failed to find block number %Lu\n",
@@ -828,49 +1601,64 @@ int btrfs_lookup_extent_ref(struct btrfs_trans_handle *trans,
                BUG();
        }
        l = path->nodes[0];
+       item_size = btrfs_item_size_nr(l, path->slots[0]);
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+       if (item_size < sizeof(*item)) {
+               ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
+                                            path, (u64)-1, 0);
+               if (ret < 0)
+                       goto out;
+
+               l = path->nodes[0];
+               item_size = btrfs_item_size_nr(l, path->slots[0]);
+       }
+#endif
+       BUG_ON(item_size < sizeof(*item));
        item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
-       *refs = btrfs_extent_refs(l, item);
+       flags |= btrfs_extent_flags(l, item);
+       btrfs_set_extent_flags(l, item, flags);
 out:
        btrfs_free_path(path);
-       return 0;
+       finish_current_insert(trans, root->fs_info->extent_root);
+       del_pending_extents(trans, root->fs_info->extent_root);
+       return ret;
 }
 
-int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
-                 struct extent_buffer *orig_buf, struct extent_buffer *buf,
-                 u32 *nr_extents)
+static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
+                          struct btrfs_root *root,
+                          struct extent_buffer *buf,
+                          int record_parent, int inc)
 {
        u64 bytenr;
+       u64 num_bytes;
+       u64 parent;
        u64 ref_root;
-       u64 orig_root;
-       u64 ref_generation;
-       u64 orig_generation;
        u32 nritems;
-       u32 nr_file_extents = 0;
        struct btrfs_key key;
        struct btrfs_file_extent_item *fi;
        int i;
        int level;
        int ret = 0;
-       int faili = 0;
-       int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
-                           u64, u64, u64, u64, u64, u64, u64, u64);
+       int (*process_func)(struct btrfs_trans_handle *trans,
+                           struct btrfs_root *root,
+                           u64, u64, u64, u64, u64, u64);
 
        ref_root = btrfs_header_owner(buf);
-       ref_generation = btrfs_header_generation(buf);
-       orig_root = btrfs_header_owner(orig_buf);
-       orig_generation = btrfs_header_generation(orig_buf);
-
        nritems = btrfs_header_nritems(buf);
        level = btrfs_header_level(buf);
 
-       if (root->ref_cows) {
-               process_func = __btrfs_inc_extent_ref;
-       } else {
-               if (level == 0 &&
-                   root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
-                       goto out;
-               process_func = __btrfs_update_extent_ref;
-       }
+       if (!root->ref_cows && level == 0)
+               return 0;
+
+       if (inc)
+               process_func = btrfs_inc_extent_ref;
+       else
+               process_func = btrfs_free_extent;
+
+       if (record_parent)
+               parent = buf->start;
+       else
+               parent = 0;
 
        for (i = 0; i < nritems; i++) {
                cond_resched();
@@ -886,151 +1674,43 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                        bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
                        if (bytenr == 0)
                                continue;
-
-                       nr_file_extents++;
-
-                       maybe_lock_mutex(root);
-                       ret = process_func(trans, root, bytenr,
-                                          orig_buf->start, buf->start,
-                                          orig_root, ref_root,
-                                          orig_generation, ref_generation,
-                                          key.objectid);
-                       maybe_unlock_mutex(root);
-
+                       
+                       num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
+                       key.offset -= btrfs_file_extent_offset(buf, fi);
+                       ret = process_func(trans, root, bytenr, num_bytes,
+                                          parent, ref_root, key.objectid,
+                                          key.offset);
                        if (ret) {
-                               faili = i;
                                WARN_ON(1);
                                goto fail;
                        }
                } else {
                        bytenr = btrfs_node_blockptr(buf, i);
-                       maybe_lock_mutex(root);
-                       ret = process_func(trans, root, bytenr,
-                                          orig_buf->start, buf->start,
-                                          orig_root, ref_root,
-                                          orig_generation, ref_generation,
-                                          level - 1);
-                       maybe_unlock_mutex(root);
+                       num_bytes = btrfs_level_size(root, level - 1);
+                       ret = process_func(trans, root, bytenr, num_bytes,
+                                          parent, ref_root, level - 1, 0);
                        if (ret) {
-                               faili = i;
                                WARN_ON(1);
                                goto fail;
                        }
                }
        }
-out:
-       if (nr_extents) {
-               if (level == 0)
-                       *nr_extents = nr_file_extents;
-               else
-                       *nr_extents = nritems;
-       }
        return 0;
 fail:
        WARN_ON(1);
-#if 0
-       for (i =0; i < faili; i++) {
-               if (level == 0) {
-                       u64 disk_bytenr;
-                       btrfs_item_key_to_cpu(buf, &key, i);
-                       if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
-                               continue;
-                       fi = btrfs_item_ptr(buf, i,
-                                           struct btrfs_file_extent_item);
-                       if (btrfs_file_extent_type(buf, fi) ==
-                           BTRFS_FILE_EXTENT_INLINE)
-                               continue;
-                       disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
-                       if (disk_bytenr == 0)
-                               continue;
-                       err = btrfs_free_extent(trans, root, disk_bytenr,
-                                   btrfs_file_extent_disk_num_bytes(buf,
-                                                                     fi), 0);
-                       BUG_ON(err);
-               } else {
-                       bytenr = btrfs_node_blockptr(buf, i);
-                       err = btrfs_free_extent(trans, root, bytenr,
-                                       btrfs_level_size(root, level - 1), 0);
-                       BUG_ON(err);
-               }
-       }
-#endif
        return ret;
 }
 
-int btrfs_update_ref(struct btrfs_trans_handle *trans,
-                    struct btrfs_root *root, struct extent_buffer *orig_buf,
-                    struct extent_buffer *buf, int start_slot, int nr)
-
+int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+                 struct extent_buffer *buf, int record_parent)
 {
-       u64 bytenr;
-       u64 ref_root;
-       u64 orig_root;
-       u64 ref_generation;
-       u64 orig_generation;
-       struct btrfs_key key;
-       struct btrfs_file_extent_item *fi;
-       int i;
-       int ret;
-       int slot;
-       int level;
-
-       BUG_ON(start_slot < 0);
-       BUG_ON(start_slot + nr > btrfs_header_nritems(buf));
-
-       ref_root = btrfs_header_owner(buf);
-       ref_generation = btrfs_header_generation(buf);
-       orig_root = btrfs_header_owner(orig_buf);
-       orig_generation = btrfs_header_generation(orig_buf);
-       level = btrfs_header_level(buf);
-
-       if (!root->ref_cows) {
-               if (level == 0 &&
-                   root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
-                       return 0;
-       }
-
-       for (i = 0, slot = start_slot; i < nr; i++, slot++) {
-               cond_resched();
-               if (level == 0) {
-                       btrfs_item_key_to_cpu(buf, &key, slot);
-                       if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
-                               continue;
-                       fi = btrfs_item_ptr(buf, slot,
-                                           struct btrfs_file_extent_item);
-                       if (btrfs_file_extent_type(buf, fi) ==
-                           BTRFS_FILE_EXTENT_INLINE)
-                               continue;
-                       bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
-                       if (bytenr == 0)
-                               continue;
+       return __btrfs_mod_ref(trans, root, buf, record_parent, 1);
+}
 
-                       maybe_lock_mutex(root);
-                       ret = __btrfs_update_extent_ref(trans, root, bytenr,
-                                           orig_buf->start, buf->start,
-                                           orig_root, ref_root,
-                                           orig_generation, ref_generation,
-                                           key.objectid);
-                       maybe_unlock_mutex(root);
-                       if (ret)
-                               goto fail;
-               } else {
-                       bytenr = btrfs_node_blockptr(buf, slot);
-                       maybe_lock_mutex(root);
-                       ret = __btrfs_update_extent_ref(trans, root, bytenr,
-                                           orig_buf->start, buf->start,
-                                           orig_root, ref_root,
-                                           orig_generation, ref_generation,
-                                           level - 1);
-                       maybe_unlock_mutex(root);
-                       if (ret)
-                               goto fail;
-               }
-       }
-       return 0;
-fail:
-       WARN_ON(1);
-       return -1;
+int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+                 struct extent_buffer *buf, int record_parent)
+{
+       return __btrfs_mod_ref(trans, root, buf, record_parent, 0);
 }
 
 static int write_one_cache_group(struct btrfs_trans_handle *trans,
@@ -1053,7 +1733,7 @@ static int write_one_cache_group(struct btrfs_trans_handle *trans,
        bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
        write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
        btrfs_mark_buffer_dirty(leaf);
-       btrfs_release_path(extent_root, path);
+       btrfs_release_path(path);
 fail:
        finish_current_insert(trans, extent_root);
        pending_ret = del_pending_extents(trans, extent_root);
@@ -1071,8 +1751,6 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
        struct extent_io_tree *block_group_cache;
        struct btrfs_block_group_cache *cache;
        int ret;
-       int err = 0;
-       int werr = 0;
        struct btrfs_path *path;
        u64 last = 0;
        u64 start;
@@ -1087,41 +1765,36 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
        while(1) {
                ret = find_first_extent_bit(block_group_cache, last,
                                            &start, &end, BLOCK_GROUP_DIRTY);
-               if (ret)
-                       break;
+               if (ret) {
+                       if (last == 0)
+                               break;
+                       last = 0;
+                       continue;
+               }
 
                last = end + 1;
                ret = get_state_private(block_group_cache, start, &ptr);
-               if (ret)
-                       break;
-               cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
-               err = write_one_cache_group(trans, root,
-                                           path, cache);
-               /*
-                * if we fail to write the cache group, we want
-                * to keep it marked dirty in hopes that a later
-                * write will work
-                */
-               if (err) {
-                       werr = err;
-                       continue;
-               }
+               BUG_ON(ret);
+
                clear_extent_bits(block_group_cache, start, end,
                                  BLOCK_GROUP_DIRTY, GFP_NOFS);
+
+               cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
+               ret = write_one_cache_group(trans, root, path, cache);
        }
        btrfs_free_path(path);
-       return werr;
+       return 0;
 }
 
 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
                                                  u64 flags)
 {
-       struct list_head *head = &info->space_info;
-       struct list_head *cur;
        struct btrfs_space_info *found;
-       list_for_each(cur, head) {
-               found = list_entry(cur, struct btrfs_space_info, list);
-               if (found->flags == flags)
+
+       flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
+
+       list_for_each_entry(found, &info->space_info, list) {
+               if (found->flags & flags)
                        return found;
        }
        return NULL;
@@ -1138,7 +1811,12 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
        if (found) {
                found->total_bytes += total_bytes;
                found->bytes_used += bytes_used;
-               WARN_ON(found->total_bytes < found->bytes_used);
+               if (found->total_bytes < found->bytes_used) {
+                       fprintf(stderr, "warning, bad space info total_bytes "
+                               "%llu used %llu\n",
+                              (unsigned long long)found->total_bytes,
+                              (unsigned long long)found->bytes_used);
+               }
                *space_info = found;
                return 0;
        }
@@ -1147,7 +1825,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
                return -ENOMEM;
 
        list_add(&found->list, &info->space_info);
-       found->flags = flags;
+       found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
        found->total_bytes = total_bytes;
        found->bytes_used = bytes_used;
        found->bytes_pinned = 0;
@@ -1161,6 +1839,9 @@ static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
 {
        u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
                                   BTRFS_BLOCK_GROUP_RAID1 |
+                                  BTRFS_BLOCK_GROUP_RAID10 |
+                                  BTRFS_BLOCK_GROUP_RAID5 |
+                                  BTRFS_BLOCK_GROUP_RAID6 |
                                   BTRFS_BLOCK_GROUP_DUP);
        if (extra_flags) {
                if (flags & BTRFS_BLOCK_GROUP_DATA)
@@ -1198,7 +1879,8 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
            thresh)
                return 0;
 
-       ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
+       ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes,
+                               space_info->flags);
        if (ret == -ENOSPC) {
                space_info->full = 1;
                return 0;
@@ -1206,7 +1888,7 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 
        BUG_ON(ret);
 
-       ret = btrfs_make_block_group(trans, extent_root, 0, flags,
+       ret = btrfs_make_block_group(trans, extent_root, 0, space_info->flags,
                     BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
        BUG_ON(ret);
        return 0;
@@ -1225,6 +1907,22 @@ static int update_block_group(struct btrfs_trans_handle *trans,
        u64 start;
        u64 end;
 
+       /* block accounting for super block */
+       old_val = btrfs_super_bytes_used(info->super_copy);
+       if (alloc)
+               old_val += num_bytes;
+       else
+               old_val -= num_bytes;
+       btrfs_set_super_bytes_used(info->super_copy, old_val);
+
+       /* block accounting for root item */
+       old_val = btrfs_root_used(&root->root_item);
+       if (alloc)
+               old_val += num_bytes;
+       else
+               old_val -= num_bytes;
+       btrfs_set_root_used(&root->root_item, old_val);
+
        while(total) {
                cache = btrfs_lookup_block_group(info, bytenr);
                if (!cache) {
@@ -1239,6 +1937,7 @@ static int update_block_group(struct btrfs_trans_handle *trans,
 
                old_val = btrfs_block_group_used(&cache->item);
                num_bytes = min(total, cache->key.offset - byte_in_group);
+
                if (alloc) {
                        old_val += num_bytes;
                        cache->space_info->bytes_used += num_bytes;
@@ -1274,6 +1973,10 @@ static int update_pinned_extents(struct btrfs_root *root,
        }
        while (num > 0) {
                cache = btrfs_lookup_block_group(fs_info, bytenr);
+               if (!cache) {
+                       len = min((u64)root->sectorsize, num);
+                       goto next;
+               }
                WARN_ON(!cache);
                len = min(num, cache->key.offset -
                          (bytenr - cache->key.objectid));
@@ -1286,31 +1989,13 @@ static int update_pinned_extents(struct btrfs_root *root,
                        cache->space_info->bytes_pinned -= len;
                        fs_info->total_pinned -= len;
                }
+next:
                bytenr += len;
                num -= len;
        }
        return 0;
 }
 
-int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
-{
-       u64 last = 0;
-       u64 start;
-       u64 end;
-       struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
-       int ret;
-
-       while(1) {
-               ret = find_first_extent_bit(pinned_extents, last,
-                                           &start, &end, EXTENT_DIRTY);
-               if (ret)
-                       break;
-               set_extent_dirty(copy, start, end, GFP_NOFS);
-               last = end + 1;
-       }
-       return 0;
-}
-
 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
                               struct btrfs_root *root,
                               struct extent_io_tree *unpin)
@@ -1333,6 +2018,21 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
        return 0;
 }
 
+static int extent_root_pending_ops(struct btrfs_fs_info *info)
+{
+       u64 start;
+       u64 end;
+       int ret;
+
+       ret = find_first_extent_bit(&info->extent_ins, 0, &start,
+                                   &end, EXTENT_LOCKED);
+       if (!ret) {
+               ret = find_first_extent_bit(&info->pending_del, 0, &start, &end,
+                                           EXTENT_LOCKED);
+       }
+       return ret == 0;
+
+}
 static int finish_current_insert(struct btrfs_trans_handle *trans,
                                 struct btrfs_root *extent_root)
 {
@@ -1340,16 +2040,12 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
        u64 end;
        u64 priv;
        struct btrfs_fs_info *info = extent_root->fs_info;
-       struct btrfs_path *path;
-       struct btrfs_extent_ref *ref;
        struct pending_extent_op *extent_op;
        struct btrfs_key key;
-       struct btrfs_extent_item extent_item;
        int ret;
-       int err = 0;
-
-       btrfs_set_stack_extent_refs(&extent_item, 1);
-       path = btrfs_alloc_path();
+       int skinny_metadata =
+               btrfs_fs_incompat(extent_root->fs_info,
+                                 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
 
        while(1) {
                ret = find_first_extent_bit(&info->extent_ins, 0, &start,
@@ -1363,50 +2059,28 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
 
                if (extent_op->type == PENDING_EXTENT_INSERT) {
                        key.objectid = start;
-                       key.offset = end + 1 - start;
-                       key.type = BTRFS_EXTENT_ITEM_KEY;
-                       err = btrfs_insert_item(trans, extent_root, &key,
-                                       &extent_item, sizeof(extent_item));
-                       BUG_ON(err);
-
-                       clear_extent_bits(&info->extent_ins, start, end,
-                                         EXTENT_LOCKED, GFP_NOFS);
-
-                       err = insert_extent_backref(trans, extent_root, path,
-                                               start, extent_op->parent,
-                                               extent_root->root_key.objectid,
-                                               extent_op->generation,
-                                               extent_op->level);
-                       BUG_ON(err);
-               } else if (extent_op->type == PENDING_BACKREF_UPDATE) {
-                       err = lookup_extent_backref(trans, extent_root, path,
-                                               start, extent_op->orig_parent,
+                       if (skinny_metadata) {
+                               key.offset = extent_op->level;
+                               key.type = BTRFS_METADATA_ITEM_KEY;
+                       } else {
+                               key.offset = extent_op->num_bytes;
+                               key.type = BTRFS_EXTENT_ITEM_KEY;
+                       }
+                       ret = alloc_reserved_tree_block(trans, extent_root,
                                                extent_root->root_key.objectid,
-                                               extent_op->orig_generation,
-                                               extent_op->level, 0);
-                       BUG_ON(err);
-
-                       clear_extent_bits(&info->extent_ins, start, end,
-                                         EXTENT_LOCKED, GFP_NOFS);
-
-                       key.objectid = start;
-                       key.offset = extent_op->parent;
-                       key.type = BTRFS_EXTENT_REF_KEY;
-                       err = btrfs_set_item_key_safe(trans, extent_root, path,
-                                                     &key);
-                       BUG_ON(err);
-                       ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
-                                            struct btrfs_extent_ref);
-                       btrfs_set_ref_generation(path->nodes[0], ref,
-                                                extent_op->generation);
-                       btrfs_mark_buffer_dirty(path->nodes[0]);
-                       btrfs_release_path(extent_root, path);
+                                               trans->transid,
+                                               extent_op->flags,
+                                               &extent_op->key,
+                                               extent_op->level, &key);
+                       BUG_ON(ret);
                } else {
                        BUG_ON(1);
                }
+
+               clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
+                                 GFP_NOFS);
                kfree(extent_op);
        }
-       btrfs_free_path(path);
        return 0;
 }
 
@@ -1433,7 +2107,6 @@ static int pin_down_bytes(struct btrfs_trans_handle *trans,
                u64 header_owner = btrfs_header_owner(buf);
                u64 header_transid = btrfs_header_generation(buf);
                if (header_owner != BTRFS_TREE_LOG_OBJECTID &&
-                   header_owner != BTRFS_TREE_RELOC_OBJECTID &&
                    header_transid == trans->transid &&
                    !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
                        clean_tree_block(NULL, root, buf);
@@ -1449,129 +2122,230 @@ pinit:
        return 0;
 }
 
+void btrfs_pin_extent(struct btrfs_fs_info *fs_info,
+                      u64 bytenr, u64 num_bytes)
+{
+       update_pinned_extents(fs_info->extent_root, bytenr, num_bytes, 1);
+}
+
+void btrfs_unpin_extent(struct btrfs_fs_info *fs_info,
+                       u64 bytenr, u64 num_bytes)
+{
+       update_pinned_extents(fs_info->extent_root, bytenr, num_bytes, 0);
+}
+
 /*
  * remove an extent from the root, returns 0 on success
  */
-static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
-                        *root, u64 bytenr, u64 num_bytes, u64 parent,
-                        u64 root_objectid, u64 ref_generation,
-                        u64 owner_objectid, int pin, int mark_free)
+static int __free_extent(struct btrfs_trans_handle *trans,
+                        struct btrfs_root *root,
+                        u64 bytenr, u64 num_bytes, u64 parent,
+                        u64 root_objectid, u64 owner_objectid,
+                        u64 owner_offset, int refs_to_drop)
 {
-       struct btrfs_path *path;
+
        struct btrfs_key key;
-       struct btrfs_fs_info *info = root->fs_info;
-       struct btrfs_extent_ops *ops = info->extent_ops;
-       struct btrfs_root *extent_root = info->extent_root;
+       struct btrfs_path *path;
+       struct btrfs_extent_ops *ops = root->fs_info->extent_ops;
+       struct btrfs_root *extent_root = root->fs_info->extent_root;
        struct extent_buffer *leaf;
+       struct btrfs_extent_item *ei;
+       struct btrfs_extent_inline_ref *iref;
        int ret;
+       int is_data;
        int extent_slot = 0;
        int found_extent = 0;
        int num_to_del = 1;
-       struct btrfs_extent_item *ei;
-       u32 refs;
+       u32 item_size;
+       u64 refs;
+       int skinny_metadata =
+               btrfs_fs_incompat(extent_root->fs_info,
+                                 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
 
-       key.objectid = bytenr;
-       btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
-       key.offset = num_bytes;
+       if (root->fs_info->free_extent_hook) {
+               root->fs_info->free_extent_hook(trans, root, bytenr, num_bytes,
+                                               parent, root_objectid, owner_objectid,
+                                               owner_offset, refs_to_drop);
 
+       }
        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;
 
-       ret = lookup_extent_backref(trans, extent_root, path,
-                                   bytenr, parent, root_objectid,
-                                   ref_generation, owner_objectid, 1);
+       path->reada = 1;
+
+       is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
+       if (is_data)
+               skinny_metadata = 0;
+       BUG_ON(!is_data && refs_to_drop != 1);
+
+       ret = lookup_extent_backref(trans, extent_root, path, &iref,
+                                   bytenr, num_bytes, parent,
+                                   root_objectid, owner_objectid,
+                                   owner_offset);
        if (ret == 0) {
-               struct btrfs_key found_key;
                extent_slot = path->slots[0];
-               while(extent_slot > 0) {
-                       extent_slot--;
-                       btrfs_item_key_to_cpu(path->nodes[0], &found_key,
+               while (extent_slot >= 0) {
+                       btrfs_item_key_to_cpu(path->nodes[0], &key,
                                              extent_slot);
-                       if (found_key.objectid != bytenr)
+                       if (key.objectid != bytenr)
+                               break;
+                       if (key.type == BTRFS_EXTENT_ITEM_KEY &&
+                           key.offset == num_bytes) {
+                               found_extent = 1;
                                break;
-                       if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
-                           found_key.offset == num_bytes) {
+                       }
+                       if (key.type == BTRFS_METADATA_ITEM_KEY &&
+                           key.offset == owner_objectid) {
                                found_extent = 1;
                                break;
                        }
                        if (path->slots[0] - extent_slot > 5)
                                break;
+                       extent_slot--;
                }
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+               item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
+               if (found_extent && item_size < sizeof(*ei))
+                       found_extent = 0;
+#endif
                if (!found_extent) {
-                       ret = remove_extent_backref(trans, extent_root, path);
+                       BUG_ON(iref);
+                       ret = remove_extent_backref(trans, extent_root, path,
+                                                   NULL, refs_to_drop,
+                                                   is_data);
                        BUG_ON(ret);
-                       btrfs_release_path(extent_root, path);
+                       btrfs_release_path(path);
+
+                       key.objectid = bytenr;
+
+                       if (skinny_metadata) {
+                               key.type = BTRFS_METADATA_ITEM_KEY;
+                               key.offset = owner_objectid;
+                       } else {
+                               key.type = BTRFS_EXTENT_ITEM_KEY;
+                               key.offset = num_bytes;
+                       }
+
                        ret = btrfs_search_slot(trans, extent_root,
                                                &key, path, -1, 1);
+                       if (ret > 0 && skinny_metadata && path->slots[0]) {
+                               path->slots[0]--;
+                               btrfs_item_key_to_cpu(path->nodes[0],
+                                                     &key,
+                                                     path->slots[0]);
+                               if (key.objectid == bytenr &&
+                                   key.type == BTRFS_EXTENT_ITEM_KEY &&
+                                   key.offset == num_bytes)
+                                       ret = 0;
+                       }
+
+                       if (ret > 0 && skinny_metadata) {
+                               skinny_metadata = 0;
+                               btrfs_release_path(path);
+                               key.type = BTRFS_EXTENT_ITEM_KEY;
+                               key.offset = num_bytes;
+                               ret = btrfs_search_slot(trans, extent_root,
+                                                       &key, path, -1, 1);
+                       }
+
+                       if (ret) {
+                               printk(KERN_ERR "umm, got %d back from search"
+                                      ", was looking for %llu\n", ret,
+                                      (unsigned long long)bytenr);
+                               btrfs_print_leaf(extent_root, path->nodes[0]);
+                       }
                        BUG_ON(ret);
                        extent_slot = path->slots[0];
                }
        } else {
-               btrfs_print_leaf(extent_root, path->nodes[0]);
-               printk("Unable to find ref byte nr %llu root %llu "
-                      " gen %llu owner %llu\n",
+               printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
+                      "parent %llu root %llu  owner %llu offset %llu\n",
                       (unsigned long long)bytenr,
+                      (unsigned long long)parent,
                       (unsigned long long)root_objectid,
-                      (unsigned long long)ref_generation,
-                      (unsigned long long)owner_objectid);
-               BUG_ON(1);
+                      (unsigned long long)owner_objectid,
+                      (unsigned long long)owner_offset);
+               ret = -EIO;
+               goto fail;
        }
 
        leaf = path->nodes[0];
+       item_size = btrfs_item_size_nr(leaf, extent_slot);
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+       if (item_size < sizeof(*ei)) {
+               BUG_ON(found_extent || extent_slot != path->slots[0]);
+               ret = convert_extent_item_v0(trans, extent_root, path,
+                                            owner_objectid, 0);
+               BUG_ON(ret < 0);
+
+               btrfs_release_path(path);
+
+               key.objectid = bytenr;
+               key.type = BTRFS_EXTENT_ITEM_KEY;
+               key.offset = num_bytes;
+
+               ret = btrfs_search_slot(trans, extent_root, &key, path,
+                                       -1, 1);
+               if (ret) {
+                       printk(KERN_ERR "umm, got %d back from search"
+                              ", was looking for %llu\n", ret,
+                              (unsigned long long)bytenr);
+                       btrfs_print_leaf(extent_root, path->nodes[0]);
+               }
+               BUG_ON(ret);
+               extent_slot = path->slots[0];
+               leaf = path->nodes[0];
+               item_size = btrfs_item_size_nr(leaf, extent_slot);
+       }
+#endif
+       BUG_ON(item_size < sizeof(*ei));
        ei = btrfs_item_ptr(leaf, extent_slot,
                            struct btrfs_extent_item);
-       refs = btrfs_extent_refs(leaf, ei);
-       BUG_ON(refs == 0);
-       refs -= 1;
-       btrfs_set_extent_refs(leaf, ei, refs);
+       if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
+           key.type == BTRFS_EXTENT_ITEM_KEY) {
+               struct btrfs_tree_block_info *bi;
+               BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
+               bi = (struct btrfs_tree_block_info *)(ei + 1);
+               WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
+       }
 
-       btrfs_mark_buffer_dirty(leaf);
+       refs = btrfs_extent_refs(leaf, ei);
+       BUG_ON(refs < refs_to_drop);
+       refs -= refs_to_drop;
 
-       if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
-               struct btrfs_extent_ref *ref;
-               ref = btrfs_item_ptr(leaf, path->slots[0],
-                                    struct btrfs_extent_ref);
-               BUG_ON(btrfs_ref_num_refs(leaf, ref) != 1);
-               /* if the back ref and the extent are next to each other
-                * they get deleted below in one shot
+       if (refs > 0) {
+               /*
+                * In the case of inline back ref, reference count will
+                * be updated by remove_extent_backref
                 */
-               path->slots[0] = extent_slot;
-               num_to_del = 2;
-       } else if (found_extent) {
-               /* otherwise delete the extent back ref */
-               ret = remove_extent_backref(trans, extent_root, path);
-               BUG_ON(ret);
-               /* if refs are 0, we need to setup the path for deletion */
-               if (refs == 0) {
-                       btrfs_release_path(extent_root, path);
-                       ret = btrfs_search_slot(trans, extent_root, &key, path,
-                                               -1, 1);
-                       if (ret < 0)
-                               return ret;
+               if (iref) {
+                       BUG_ON(!found_extent);
+               } else {
+                       btrfs_set_extent_refs(leaf, ei, refs);
+                       btrfs_mark_buffer_dirty(leaf);
+               }
+               if (found_extent) {
+                       ret = remove_extent_backref(trans, extent_root, path,
+                                                   iref, refs_to_drop,
+                                                   is_data);
                        BUG_ON(ret);
                }
-       }
-
-       if (refs == 0) {
-               u64 super_used;
-               u64 root_used;
-
-
-
-               /* block accounting for super block */
-               super_used = btrfs_super_bytes_used(&info->super_copy);
-               btrfs_set_super_bytes_used(&info->super_copy,
-                                          super_used - num_bytes);
-
-               /* block accounting for root item */
-               root_used = btrfs_root_used(&root->root_item);
-               btrfs_set_root_used(&root->root_item,
-                                          root_used - num_bytes);
-               ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
-                                     num_to_del);
-               if (ret)
-                       return ret;
+       } else {
+               int mark_free = 0;
+               int pin = 1;
+
+               if (found_extent) {
+                       BUG_ON(is_data && refs_to_drop !=
+                              extent_data_ref_count(root, path, iref));
+                       if (iref) {
+                               BUG_ON(path->slots[0] != extent_slot);
+                       } else {
+                               BUG_ON(path->slots[0] != extent_slot + 1);
+                               path->slots[0] = extent_slot;
+                               num_to_del = 2;
+                       }
+               }
 
                if (ops && ops->free_extent) {
                        ret = ops->free_extent(root, bytenr, num_bytes);
@@ -1582,21 +2356,26 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                }
 
                if (pin) {
-                       ret = pin_down_bytes(trans, root, bytenr, num_bytes, 0);
+                       ret = pin_down_bytes(trans, root, bytenr, num_bytes,
+                                            is_data);
                        if (ret > 0)
                                mark_free = 1;
                        BUG_ON(ret < 0);
                }
 
-               if (owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
+               ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
+                                     num_to_del);
+               BUG_ON(ret);
+               btrfs_release_path(path);
+
+               if (is_data) {
                        ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
                        BUG_ON(ret);
                }
 
-               ret = update_block_group(trans, root, bytenr, num_bytes, 0,
-                                        mark_free);
-               BUG_ON(ret);
+               update_block_group(trans, root, bytenr, num_bytes, 0, mark_free);
        }
+fail:
        btrfs_free_path(path);
        finish_current_insert(trans, extent_root);
        return ret;
@@ -1611,7 +2390,6 @@ static int del_pending_extents(struct btrfs_trans_handle *trans, struct
 {
        int ret;
        int err = 0;
-       int mark_free = 0;
        u64 start;
        u64 end;
        u64 priv;
@@ -1635,18 +2413,12 @@ static int del_pending_extents(struct btrfs_trans_handle *trans, struct
                clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
                                  GFP_NOFS);
 
-               ret = pin_down_bytes(trans, extent_root, start,
-                                    end + 1 - start, 0);
-               mark_free = ret > 0;
                if (!test_range_bit(extent_ins, start, end,
                                    EXTENT_LOCKED, 0)) {
-free_extent:
                        ret = __free_extent(trans, extent_root,
-                                           start, end + 1 - start,
-                                           extent_op->orig_parent,
+                                           start, end + 1 - start, 0,
                                            extent_root->root_key.objectid,
-                                           extent_op->orig_generation,
-                                           extent_op->level, 0, mark_free);
+                                           extent_op->level, 0, 1);
                        kfree(extent_op);
                } else {
                        kfree(extent_op);
@@ -1659,11 +2431,8 @@ free_extent:
                                          EXTENT_LOCKED, GFP_NOFS);
 
                        if (extent_op->type == PENDING_BACKREF_UPDATE)
-                               goto free_extent;
+                               BUG_ON(1);
 
-                       ret = update_block_group(trans, extent_root, start,
-                                               end + 1 - start, 0, mark_free);
-                       BUG_ON(ret);
                        kfree(extent_op);
                }
                if (ret)
@@ -1675,10 +2444,11 @@ free_extent:
 /*
  * remove an extent from the root, returns 0 on success
  */
-int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
-                     *root, u64 bytenr, u64 num_bytes, u64 parent,
-                     u64 root_objectid, u64 ref_generation,
-                     u64 owner_objectid, int pin)
+
+int btrfs_free_extent(struct btrfs_trans_handle *trans,
+                     struct btrfs_root *root,
+                     u64 bytenr, u64 num_bytes, u64 parent,
+                     u64 root_objectid, u64 owner, u64 offset)
 {
        struct btrfs_root *extent_root = root->fs_info->extent_root;
        int pending_ret;
@@ -1694,11 +2464,7 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                extent_op->type = PENDING_EXTENT_DELETE;
                extent_op->bytenr = bytenr;
                extent_op->num_bytes = num_bytes;
-               extent_op->parent = parent;
-               extent_op->orig_parent = parent;
-               extent_op->generation = ref_generation;
-               extent_op->orig_generation = ref_generation;
-               extent_op->level = (int)owner_objectid;
+               extent_op->level = (int)owner;
 
                set_extent_bits(&root->fs_info->pending_del,
                                bytenr, bytenr + num_bytes - 1,
@@ -1708,8 +2474,7 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                return 0;
        }
        ret = __free_extent(trans, root, bytenr, num_bytes, parent,
-                           root_objectid, ref_generation,
-                           owner_objectid, pin, pin == 0);
+                           root_objectid, owner, offset, 1);
        pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
        return ret ? ret : pending_ret;
 }
@@ -1749,6 +2514,8 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans,
        WARN_ON(num_bytes < root->sectorsize);
        btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
 
+       search_start = stripe_align(root, search_start);
+
        if (hint_byte) {
                block_group = btrfs_lookup_first_block_group(info, hint_byte);
                if (!block_group)
@@ -1764,6 +2531,7 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans,
        total_needed += empty_size;
 
 check_failed:
+       search_start = stripe_align(root, search_start);
        if (!block_group) {
                block_group = btrfs_lookup_first_block_group(info,
                                                             search_start);
@@ -1774,9 +2542,8 @@ check_failed:
        ret = find_search_start(root, &block_group, &search_start,
                                total_needed, data);
        if (ret)
-               goto error;
+               goto new_group;
 
-       search_start = stripe_align(root, search_start);
        ins->objectid = search_start;
        ins->offset = num_bytes;
 
@@ -1799,6 +2566,13 @@ check_failed:
                goto new_group;
        }
 
+       if (info->excluded_extents &&
+           test_range_bit(info->excluded_extents, ins->objectid,
+                          ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
+               search_start = ins->objectid + num_bytes;
+               goto new_group;
+       }
+
        if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
            ins->objectid < exclude_start + exclude_nr)) {
                search_start = exclude_start + exclude_nr;
@@ -1836,32 +2610,17 @@ new_group:
 error:
        return ret;
 }
-/*
- * finds a free extent and does all the dirty work required for allocation
- * returns the key for the extent through ins, and a tree buffer for
- * the first block of the extent through buf.
- *
- * returns 0 if everything worked, non-zero otherwise.
- */
-int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
-                      struct btrfs_root *root,
-                      u64 num_bytes, u64 parent,
-                      u64 root_objectid, u64 ref_generation,
-                      u64 owner, u64 empty_size, u64 hint_byte,
-                      u64 search_end, struct btrfs_key *ins, int data)
+
+int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
+                        struct btrfs_root *root,
+                        u64 num_bytes, u64 empty_size,
+                        u64 hint_byte, u64 search_end,
+                        struct btrfs_key *ins, int data)
 {
        int ret;
-       int pending_ret;
-       u64 super_used, root_used;
        u64 search_start = 0;
        u64 alloc_profile;
-       u32 sizes[2];
        struct btrfs_fs_info *info = root->fs_info;
-       struct btrfs_root *extent_root = info->extent_root;
-       struct btrfs_path *path;
-       struct btrfs_extent_item *extent_item;
-       struct btrfs_extent_ref *ref;
-       struct btrfs_key keys[2];
 
        if (info->extent_ops) {
                struct btrfs_extent_ops *ops = info->extent_ops;
@@ -1904,25 +2663,81 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
                               trans->alloc_exclude_nr, data);
        BUG_ON(ret);
 found:
-       if (ret)
-               return ret;
+       clear_extent_dirty(&root->fs_info->free_space_cache,
+                          ins->objectid, ins->objectid + ins->offset - 1,
+                          GFP_NOFS);
+       return ret;
+}
 
-       if (parent == 0)
-               parent = ins->objectid;
+static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
+                                    struct btrfs_root *root,
+                                    u64 root_objectid, u64 generation,
+                                    u64 flags, struct btrfs_disk_key *key,
+                                    int level, struct btrfs_key *ins)
+{
+       int ret;
+       struct btrfs_fs_info *fs_info = root->fs_info;
+       struct btrfs_extent_item *extent_item;
+       struct btrfs_tree_block_info *block_info;
+       struct btrfs_extent_inline_ref *iref;
+       struct btrfs_path *path;
+       struct extent_buffer *leaf;
+       u32 size = sizeof(*extent_item) + sizeof(*iref);
+       int skinny_metadata =
+               btrfs_fs_incompat(fs_info,
+                                 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
 
-       /* block accounting for super block */
-       super_used = btrfs_super_bytes_used(&info->super_copy);
-       btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
+       if (!skinny_metadata)
+               size += sizeof(*block_info);
 
-       /* block accounting for root item */
-       root_used = btrfs_root_used(&root->root_item);
-       btrfs_set_root_used(&root->root_item, root_used + num_bytes);
+       path = btrfs_alloc_path();
+       BUG_ON(!path);
 
-       clear_extent_dirty(&root->fs_info->free_space_cache,
-                          ins->objectid, ins->objectid + ins->offset - 1,
-                          GFP_NOFS);
+       ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
+                                     ins, size);
+       BUG_ON(ret);
 
-       if (root == extent_root) {
+       leaf = path->nodes[0];
+       extent_item = btrfs_item_ptr(leaf, path->slots[0],
+                                    struct btrfs_extent_item);
+       btrfs_set_extent_refs(leaf, extent_item, 1);
+       btrfs_set_extent_generation(leaf, extent_item, generation);
+       btrfs_set_extent_flags(leaf, extent_item,
+                              flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
+
+       if (skinny_metadata) {
+               iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
+       } else {
+               block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
+               btrfs_set_tree_block_key(leaf, block_info, key);
+               btrfs_set_tree_block_level(leaf, block_info, level);
+               iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
+       }
+
+       btrfs_set_extent_inline_ref_type(leaf, iref, BTRFS_TREE_BLOCK_REF_KEY);
+       btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
+
+       btrfs_mark_buffer_dirty(leaf);
+       btrfs_free_path(path);
+
+       ret = update_block_group(trans, root, ins->objectid, root->leafsize,
+                                1, 0);
+       return ret;
+}
+
+static int alloc_tree_block(struct btrfs_trans_handle *trans,
+                           struct btrfs_root *root, u64 num_bytes,
+                           u64 root_objectid, u64 generation,
+                           u64 flags, struct btrfs_disk_key *key,
+                           int level, u64 empty_size, u64 hint_byte,
+                           u64 search_end, struct btrfs_key *ins)
+{
+       int ret;
+       ret = btrfs_reserve_extent(trans, root, num_bytes, empty_size,
+                                  hint_byte, search_end, ins, 0);
+       BUG_ON(ret);
+
+       if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID) {
                struct pending_extent_op *extent_op;
 
                extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
@@ -1931,73 +2746,28 @@ found:
                extent_op->type = PENDING_EXTENT_INSERT;
                extent_op->bytenr = ins->objectid;
                extent_op->num_bytes = ins->offset;
-               extent_op->parent = parent;
-               extent_op->orig_parent = 0;
-               extent_op->generation = ref_generation;
-               extent_op->orig_generation = 0;
-               extent_op->level = (int)owner;
+               extent_op->level = level;
+               extent_op->flags = flags;
+               memcpy(&extent_op->key, key, sizeof(*key));
 
                set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
                                ins->objectid + ins->offset - 1,
                                EXTENT_LOCKED, GFP_NOFS);
                set_state_private(&root->fs_info->extent_ins,
                                  ins->objectid, (unsigned long)extent_op);
-               goto update_block;
-       }
-
-       WARN_ON(trans->alloc_exclude_nr);
-       trans->alloc_exclude_start = ins->objectid;
-       trans->alloc_exclude_nr = ins->offset;
-
-       memcpy(&keys[0], ins, sizeof(*ins));
-       keys[1].objectid = ins->objectid;
-       keys[1].type = BTRFS_EXTENT_REF_KEY;
-       keys[1].offset = parent;
-       sizes[0] = sizeof(*extent_item);
-       sizes[1] = sizeof(*ref);
-
-       path = btrfs_alloc_path();
-       BUG_ON(!path);
-
-       ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
-                                      sizes, 2);
-
-       BUG_ON(ret);
-       extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
-                                    struct btrfs_extent_item);
-       btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
-       ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
-                            struct btrfs_extent_ref);
-
-       btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
-       btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
-       btrfs_set_ref_objectid(path->nodes[0], ref, owner);
-       btrfs_set_ref_num_refs(path->nodes[0], ref, 1);
-
-       btrfs_mark_buffer_dirty(path->nodes[0]);
-
-       trans->alloc_exclude_start = 0;
-       trans->alloc_exclude_nr = 0;
-       btrfs_free_path(path);
-       finish_current_insert(trans, extent_root);
-       pending_ret = del_pending_extents(trans, extent_root);
-
-       if (ret) {
-               return ret;
-       }
-       if (pending_ret) {
-               return pending_ret;
-       }
-
-update_block:
-       ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
-       if (ret) {
-               printk("update block group failed for %llu %llu\n",
-                      (unsigned long long)ins->objectid,
-                      (unsigned long long)ins->offset);
-               BUG();
+       } else {
+               if (btrfs_fs_incompat(root->fs_info,
+                               BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)) {
+                       ins->offset = level;
+                       ins->type = BTRFS_METADATA_ITEM_KEY;
+               }
+               ret = alloc_reserved_tree_block(trans, root, root_objectid,
+                                               generation, flags,
+                                               key, level, ins);
+               finish_current_insert(trans, root->fs_info->extent_root);
+               del_pending_extents(trans, root->fs_info->extent_root);
        }
-       return 0;
+       return ret;
 }
 
 /*
@@ -2005,41 +2775,38 @@ update_block:
  * returns the tree buffer or NULL.
  */
 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
-                                            struct btrfs_root *root,
-                                            u32 blocksize, u64 parent,
-                                            u64 root_objectid,
-                                            u64 ref_generation,
-                                            int level,
-                                            u64 hint,
-                                            u64 empty_size)
+                                       struct btrfs_root *root,
+                                       u32 blocksize, u64 root_objectid,
+                                       struct btrfs_disk_key *key, int level,
+                                       u64 hint, u64 empty_size)
 {
        struct btrfs_key ins;
        int ret;
        struct extent_buffer *buf;
 
-       ret = btrfs_alloc_extent(trans, root, blocksize, parent,
-                                root_objectid, ref_generation,
-                                level, empty_size, hint,
-                                (u64)-1, &ins, 0);
+       ret = alloc_tree_block(trans, root, blocksize, root_objectid,
+                              trans->transid, 0, key, level,
+                              empty_size, hint, (u64)-1, &ins);
        if (ret) {
                BUG_ON(ret > 0);
                return ERR_PTR(ret);
        }
+
        buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
        if (!buf) {
-               if (parent == 0)
-                       parent = ins.objectid;
-               btrfs_free_extent(trans, root, ins.objectid, blocksize,
-                                 parent, root->root_key.objectid,
-                                 ref_generation, level, 0);
+               btrfs_free_extent(trans, root, ins.objectid, ins.offset,
+                                 0, root->root_key.objectid, level, 0);
                BUG_ON(1);
                return ERR_PTR(-ENOMEM);
        }
        btrfs_set_buffer_uptodate(buf);
        trans->blocks_used++;
+
        return buf;
 }
 
+#if 0
+
 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
                                  struct btrfs_root *root,
                                  struct extent_buffer *leaf)
@@ -2202,6 +2969,13 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
                        next = read_tree_block(root, bytenr, blocksize,
                                               ptr_gen);
                        mutex_lock(&root->fs_info->fs_mutex);
+                       if (!extent_buffer_uptodate(next)) {
+                               if (IS_ERR(next))
+                                       ret = PTR_ERR(next);
+                               else
+                                       ret = -EIO;
+                               break;
+                       }
                }
                WARN_ON(*level <= 0);
                if (path->nodes[*level-1])
@@ -2286,91 +3060,31 @@ static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
        return 1;
 }
 
-/*
- * drop the reference count on the tree rooted at 'snap'.  This traverses
- * the tree freeing any blocks that have a ref count of zero after being
- * decremented.
- */
-int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
-                       *root)
-{
-       int ret = 0;
-       int wret;
-       int level;
-       struct btrfs_path *path;
-       int i;
-       int orig_level;
-       struct btrfs_root_item *root_item = &root->root_item;
-
-       path = btrfs_alloc_path();
-       BUG_ON(!path);
-
-       level = btrfs_header_level(root->node);
-       orig_level = level;
-       if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
-               path->nodes[level] = root->node;
-               extent_buffer_get(root->node);
-               path->slots[level] = 0;
-       } else {
-               struct btrfs_key key;
-               struct btrfs_disk_key found_key;
-               struct extent_buffer *node;
-
-               btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
-               level = root_item->drop_level;
-               path->lowest_level = level;
-               wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-               if (wret < 0) {
-                       ret = wret;
-                       goto out;
-               }
-               node = path->nodes[level];
-               btrfs_node_key(node, &found_key, path->slots[level]);
-               WARN_ON(memcmp(&found_key, &root_item->drop_progress,
-                              sizeof(found_key)));
-       }
-       while(1) {
-               wret = walk_down_tree(trans, root, path, &level);
-               if (wret < 0)
-                       ret = wret;
-               if (wret != 0)
-                       break;
-
-               wret = walk_up_tree(trans, root, path, &level);
-               if (wret < 0)
-                       ret = wret;
-               if (wret != 0)
-                       break;
-               /*
-               ret = -EAGAIN;
-               break;
-               */
-       }
-       for (i = 0; i <= orig_level; i++) {
-               if (path->nodes[i]) {
-                       free_extent_buffer(path->nodes[i]);
-                       path->nodes[i] = NULL;
-               }
-       }
-out:
-       btrfs_free_path(path);
-       return ret;
-}
+#endif
 
 int btrfs_free_block_groups(struct btrfs_fs_info *info)
 {
+       struct btrfs_space_info *sinfo;
+       struct btrfs_block_group_cache *cache;
        u64 start;
        u64 end;
        u64 ptr;
        int ret;
+
        while(1) {
                ret = find_first_extent_bit(&info->block_group_cache, 0,
                                            &start, &end, (unsigned int)-1);
                if (ret)
                        break;
                ret = get_state_private(&info->block_group_cache, start, &ptr);
-               if (!ret)
-                       kfree((void *)(unsigned long)ptr);
+               if (!ret) {
+                       cache = u64_to_ptr(ptr);
+                       if (cache->free_space_ctl) {
+                               btrfs_remove_free_space_cache(cache);
+                               kfree(cache->free_space_ctl);
+                       }
+                       kfree(cache);
+               }
                clear_extent_bits(&info->block_group_cache, start,
                                  end, (unsigned int)-1, GFP_NOFS);
        }
@@ -2382,11 +3096,18 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
                clear_extent_dirty(&info->free_space_cache, start,
                                   end, GFP_NOFS);
        }
+
+       while (!list_empty(&info->space_info)) {
+               sinfo = list_entry(info->space_info.next,
+                                  struct btrfs_space_info, list);
+               list_del_init(&sinfo->list);
+               kfree(sinfo);
+       }
        return 0;
 }
 
-int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
-                          struct btrfs_key *key)
+static int find_first_block_group(struct btrfs_root *root,
+               struct btrfs_path *path, struct btrfs_key *key)
 {
        int ret;
        struct btrfs_key found_key;
@@ -2419,6 +3140,54 @@ error:
        return ret;
 }
 
+static void account_super_bytes(struct btrfs_fs_info *fs_info,
+                               struct btrfs_block_group_cache *cache)
+{
+       u64 bytenr;
+       u64 *logical;
+       int stripe_len;
+       int i, nr, ret;
+
+       if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
+               stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
+               cache->bytes_super += stripe_len;
+       }
+
+       for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+               bytenr = btrfs_sb_offset(i);
+               ret = btrfs_rmap_block(&fs_info->mapping_tree,
+                                      cache->key.objectid, bytenr,
+                                      0, &logical, &nr, &stripe_len);
+               if (ret)
+                       return;
+
+               while (nr--) {
+                       u64 start, len;
+
+                       if (logical[nr] > cache->key.objectid +
+                           cache->key.offset)
+                               continue;
+
+                       if (logical[nr] + stripe_len <= cache->key.objectid)
+                               continue;
+
+                       start = logical[nr];
+                       if (start < cache->key.objectid) {
+                               start = cache->key.objectid;
+                               len = (logical[nr] + stripe_len) - start;
+                       } else {
+                               len = min_t(u64, stripe_len,
+                                           cache->key.objectid +
+                                           cache->key.offset - start);
+                       }
+
+                       cache->bytes_super += len;
+               }
+
+               kfree(logical);
+       }
+}
+
 int btrfs_read_block_groups(struct btrfs_root *root)
 {
        struct btrfs_path *path;
@@ -2466,7 +3235,7 @@ int btrfs_read_block_groups(struct btrfs_root *root)
                cache->cached = 0;
                cache->pinned = 0;
                key.objectid = found_key.objectid + found_key.offset;
-               btrfs_release_path(root, path);
+               btrfs_release_path(path);
                cache->flags = btrfs_block_group_flags(&cache->item);
                bit = 0;
                if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
@@ -2480,6 +3249,8 @@ int btrfs_read_block_groups(struct btrfs_root *root)
                if (btrfs_chunk_readonly(root, cache->key.objectid))
                        cache->ro = 1;
 
+               account_super_bytes(info, cache);
+
                ret = update_space_info(info, cache->flags, found_key.offset,
                                        btrfs_block_group_used(&cache->item),
                                        &space_info);
@@ -2499,19 +3270,16 @@ error:
        return ret;
 }
 
-int btrfs_make_block_group(struct btrfs_trans_handle *trans,
-                          struct btrfs_root *root, u64 bytes_used,
-                          u64 type, u64 chunk_objectid, u64 chunk_offset,
-                          u64 size)
+struct btrfs_block_group_cache *
+btrfs_add_block_group(struct btrfs_fs_info *fs_info, u64 bytes_used, u64 type,
+                     u64 chunk_objectid, u64 chunk_offset, u64 size)
 {
        int ret;
        int bit = 0;
-       struct btrfs_root *extent_root;
        struct btrfs_block_group_cache *cache;
        struct extent_io_tree *block_group_cache;
 
-       extent_root = root->fs_info->extent_root;
-       block_group_cache = &root->fs_info->block_group_cache;
+       block_group_cache = &fs_info->block_group_cache;
 
        cache = kzalloc(sizeof(*cache), GFP_NOFS);
        BUG_ON(!cache);
@@ -2524,25 +3292,46 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
        cache->flags = type;
        btrfs_set_block_group_flags(&cache->item, type);
 
-       ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
+       account_super_bytes(fs_info, cache);
+       ret = update_space_info(fs_info, cache->flags, size, bytes_used,
                                &cache->space_info);
        BUG_ON(ret);
 
        bit = block_group_state_bits(type);
-       set_extent_bits(block_group_cache, chunk_offset,
-                       chunk_offset + size - 1,
-                       bit | EXTENT_LOCKED, GFP_NOFS);
+       ret = set_extent_bits(block_group_cache, chunk_offset,
+                             chunk_offset + size - 1,
+                             bit | EXTENT_LOCKED, GFP_NOFS);
+       BUG_ON(ret);
+
+       ret = set_state_private(block_group_cache, chunk_offset,
+                               (unsigned long)cache);
+       BUG_ON(ret);
+       set_avail_alloc_bits(fs_info, type);
+
+       return cache;
+}
+
+int btrfs_make_block_group(struct btrfs_trans_handle *trans,
+                          struct btrfs_root *root, u64 bytes_used,
+                          u64 type, u64 chunk_objectid, u64 chunk_offset,
+                          u64 size)
+{
+       int ret;
+       struct btrfs_root *extent_root;
+       struct btrfs_block_group_cache *cache;
 
-       set_state_private(block_group_cache, chunk_offset,
-                         (unsigned long)cache);
+       cache = btrfs_add_block_group(root->fs_info, bytes_used, type,
+                                     chunk_objectid, chunk_offset, size);
+       extent_root = root->fs_info->extent_root;
        ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
                                sizeof(cache->item));
        BUG_ON(ret);
 
-       finish_current_insert(trans, extent_root);
+       ret = finish_current_insert(trans, extent_root);
+       BUG_ON(ret);
        ret = del_pending_extents(trans, extent_root);
        BUG_ON(ret);
-       set_avail_alloc_bits(extent_root->fs_info, type);
+
        return 0;
 }
 
@@ -2573,7 +3362,7 @@ int btrfs_make_block_groups(struct btrfs_trans_handle *trans,
        extent_root = root->fs_info->extent_root;
        block_group_cache = &root->fs_info->block_group_cache;
        chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
-       total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
+       total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
        group_align = 64 * root->sectorsize;
 
        cur_start = 0;
@@ -2657,3 +3446,177 @@ int btrfs_update_block_group(struct btrfs_trans_handle *trans,
        return update_block_group(trans, root, bytenr, num_bytes,
                                  alloc, mark_free);
 }
+
+/*
+ * Fixup block accounting. The initial block accounting created by
+ * make_block_groups isn't accuracy in this case.
+ */
+int btrfs_fix_block_accounting(struct btrfs_trans_handle *trans,
+                              struct btrfs_root *root)
+{
+       int ret;
+       int slot;
+       u64 start = 0;
+       u64 bytes_used = 0;
+       struct btrfs_path path;
+       struct btrfs_key key;
+       struct extent_buffer *leaf;
+       struct btrfs_block_group_cache *cache;
+       struct btrfs_fs_info *fs_info = root->fs_info;
+
+       root = root->fs_info->extent_root;
+
+       while(extent_root_pending_ops(fs_info)) {
+               ret = finish_current_insert(trans, root);
+               if (ret)
+                       return ret;
+               ret = del_pending_extents(trans, root);
+               if (ret)
+                       return ret;
+       }
+
+       while(1) {
+               cache = btrfs_lookup_first_block_group(fs_info, start);
+               if (!cache)
+                       break;
+               start = cache->key.objectid + cache->key.offset;
+               btrfs_set_block_group_used(&cache->item, 0);
+               cache->space_info->bytes_used = 0;
+               set_extent_bits(&root->fs_info->block_group_cache,
+                               cache->key.objectid,
+                               cache->key.objectid + cache->key.offset -1,
+                               BLOCK_GROUP_DIRTY, GFP_NOFS);
+       }
+
+       btrfs_init_path(&path);
+       key.offset = 0;
+       key.objectid = 0;
+       btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
+       ret = btrfs_search_slot(trans, root->fs_info->extent_root,
+                               &key, &path, 0, 0);
+       if (ret < 0)
+               return ret;
+       while(1) {
+               leaf = path.nodes[0];
+               slot = path.slots[0];
+               if (slot >= btrfs_header_nritems(leaf)) {
+                       ret = btrfs_next_leaf(root, &path);
+                       if (ret < 0)
+                               return ret;
+                       if (ret > 0)
+                               break;
+                       leaf = path.nodes[0];
+                       slot = path.slots[0];
+               }
+               btrfs_item_key_to_cpu(leaf, &key, slot);
+               if (key.type == BTRFS_EXTENT_ITEM_KEY) {
+                       bytes_used += key.offset;
+                       ret = btrfs_update_block_group(trans, root,
+                                 key.objectid, key.offset, 1, 0);
+                       BUG_ON(ret);
+               } else if (key.type == BTRFS_METADATA_ITEM_KEY) {
+                       bytes_used += root->leafsize;
+                       ret = btrfs_update_block_group(trans, root,
+                                 key.objectid, root->leafsize, 1, 0);
+                       BUG_ON(ret);
+               }
+               path.slots[0]++;
+       }
+       btrfs_set_super_bytes_used(root->fs_info->super_copy, bytes_used);
+       btrfs_release_path(&path);
+       return 0;
+}
+
+/*
+ * Record a file extent. Do all the required works, such as inserting
+ * file extent item, inserting extent item and backref item into extent
+ * tree and updating block accounting.
+ */
+int btrfs_record_file_extent(struct btrfs_trans_handle *trans,
+                             struct btrfs_root *root, u64 objectid,
+                             struct btrfs_inode_item *inode,
+                             u64 file_pos, u64 disk_bytenr,
+                             u64 num_bytes)
+{
+       int ret;
+       struct btrfs_fs_info *info = root->fs_info;
+       struct btrfs_root *extent_root = info->extent_root;
+       struct extent_buffer *leaf;
+       struct btrfs_file_extent_item *fi;
+       struct btrfs_key ins_key;
+       struct btrfs_path path;
+       struct btrfs_extent_item *ei;
+       u64 nbytes;
+
+       if (disk_bytenr == 0) {
+               ret = btrfs_insert_file_extent(trans, root, objectid,
+                                               file_pos, disk_bytenr,
+                                               num_bytes, num_bytes);
+               return ret;
+       }
+
+       btrfs_init_path(&path);
+
+       ins_key.objectid = objectid;
+       ins_key.offset = file_pos;
+       btrfs_set_key_type(&ins_key, BTRFS_EXTENT_DATA_KEY);
+       ret = btrfs_insert_empty_item(trans, root, &path, &ins_key,
+                                     sizeof(*fi));
+       if (ret)
+               goto fail;
+       leaf = path.nodes[0];
+       fi = btrfs_item_ptr(leaf, path.slots[0],
+                           struct btrfs_file_extent_item);
+       btrfs_set_file_extent_generation(leaf, fi, trans->transid);
+       btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
+       btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
+       btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
+       btrfs_set_file_extent_offset(leaf, fi, 0);
+       btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
+       btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
+       btrfs_set_file_extent_compression(leaf, fi, 0);
+       btrfs_set_file_extent_encryption(leaf, fi, 0);
+       btrfs_set_file_extent_other_encoding(leaf, fi, 0);
+       btrfs_mark_buffer_dirty(leaf);
+
+       nbytes = btrfs_stack_inode_nbytes(inode) + num_bytes;
+       btrfs_set_stack_inode_nbytes(inode, nbytes);
+
+       btrfs_release_path(&path);
+
+       ins_key.objectid = disk_bytenr;
+       ins_key.offset = num_bytes;
+       ins_key.type = BTRFS_EXTENT_ITEM_KEY;
+
+       ret = btrfs_insert_empty_item(trans, extent_root, &path,
+                                     &ins_key, sizeof(*ei));
+       if (ret == 0) {
+               leaf = path.nodes[0];
+               ei = btrfs_item_ptr(leaf, path.slots[0],
+                                   struct btrfs_extent_item);
+
+               btrfs_set_extent_refs(leaf, ei, 0);
+               btrfs_set_extent_generation(leaf, ei, 0);
+               btrfs_set_extent_flags(leaf, ei, BTRFS_EXTENT_FLAG_DATA);
+
+               btrfs_mark_buffer_dirty(leaf);
+
+               ret = btrfs_update_block_group(trans, root, disk_bytenr,
+                                              num_bytes, 1, 0);
+               if (ret)
+                       goto fail;
+       } else if (ret != -EEXIST) {
+               goto fail;
+       }
+       btrfs_extent_post_op(trans, extent_root);
+
+       ret = btrfs_inc_extent_ref(trans, root, disk_bytenr, num_bytes, 0,
+                                  root->root_key.objectid,
+                                  objectid, file_pos);
+       if (ret)
+               goto fail;
+       ret = 0;
+fail:
+       btrfs_release_path(&path);
+       return ret;
+}