]> git.karo-electronics.de Git - mv-sheeva.git/blobdiff - fs/btrfs/extent-tree.c
Btrfs: prevent looping forever in finish_current_insert and del_pending_extents
[mv-sheeva.git] / fs / btrfs / extent-tree.c
index 280ac1aa9b6d7d39816a24283836cdaa6de60cf4..fada9c22a021180a2c6a5dd8fb84f79d419a0f19 100644 (file)
@@ -45,32 +45,14 @@ struct pending_extent_op {
 };
 
 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
-                                btrfs_root *extent_root);
+                                btrfs_root *extent_root, int all);
 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
-                              btrfs_root *extent_root);
+                              btrfs_root *extent_root, int all);
 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);
 
-void maybe_lock_mutex(struct btrfs_root *root)
-{
-       if (root != root->fs_info->extent_root &&
-           root != root->fs_info->chunk_root &&
-           root != root->fs_info->dev_root) {
-               mutex_lock(&root->fs_info->alloc_mutex);
-       }
-}
-
-void maybe_unlock_mutex(struct btrfs_root *root)
-{
-       if (root != root->fs_info->extent_root &&
-           root != root->fs_info->chunk_root &&
-           root != root->fs_info->dev_root) {
-               mutex_unlock(&root->fs_info->alloc_mutex);
-       }
-}
-
 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 {
        return (cache->flags & bits) == bits;
@@ -164,6 +146,7 @@ static int add_new_free_space(struct btrfs_block_group_cache *block_group,
        u64 extent_start, extent_end, size;
        int ret;
 
+       mutex_lock(&info->pinned_mutex);
        while (start < end) {
                ret = find_first_extent_bit(&info->pinned_extents, start,
                                            &extent_start, &extent_end,
@@ -175,7 +158,8 @@ static int add_new_free_space(struct btrfs_block_group_cache *block_group,
                        start = extent_end + 1;
                } else if (extent_start > start && extent_start < end) {
                        size = extent_start - start;
-                       ret = btrfs_add_free_space(block_group, start, size);
+                       ret = btrfs_add_free_space_lock(block_group, start,
+                                                       size);
                        BUG_ON(ret);
                        start = extent_end + 1;
                } else {
@@ -185,9 +169,10 @@ static int add_new_free_space(struct btrfs_block_group_cache *block_group,
 
        if (start < end) {
                size = end - start;
-               ret = btrfs_add_free_space(block_group, start, size);
+               ret = btrfs_add_free_space_lock(block_group, start, size);
                BUG_ON(ret);
        }
+       mutex_unlock(&info->pinned_mutex);
 
        return 0;
 }
@@ -317,59 +302,6 @@ struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
        return cache;
 }
 
-static int noinline find_free_space(struct btrfs_root *root,
-                                   struct btrfs_block_group_cache **cache_ret,
-                                   u64 *start_ret, u64 num, int data)
-{
-       int ret;
-       struct btrfs_block_group_cache *cache = *cache_ret;
-       struct btrfs_free_space *info = NULL;
-       u64 last;
-       u64 search_start = *start_ret;
-
-       WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
-       if (!cache)
-               goto out;
-
-       last = max(search_start, cache->key.objectid);
-
-again:
-       ret = cache_block_group(root, cache);
-       if (ret)
-               goto out;
-
-       if (cache->ro || !block_group_bits(cache, data))
-               goto new_group;
-
-       info = btrfs_find_free_space(cache, last, num);
-       if (info) {
-               *start_ret = info->offset;
-               return 0;
-       }
-
-new_group:
-       last = cache->key.objectid + cache->key.offset;
-
-       cache = btrfs_lookup_first_block_group(root->fs_info, last);
-       if (!cache)
-               goto out;
-
-       *cache_ret = cache;
-       goto again;
-
-out:
-       return -ENOSPC;
-}
-
-static u64 div_factor(u64 num, int factor)
-{
-       if (factor == 10)
-               return num;
-       num *= factor;
-       do_div(num, 10);
-       return num;
-}
-
 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
                                                  u64 flags)
 {
@@ -384,6 +316,15 @@ static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
        return NULL;
 }
 
+static u64 div_factor(u64 num, int factor)
+{
+       if (factor == 10)
+               return num;
+       num *= factor;
+       do_div(num, 10);
+       return num;
+}
+
 static struct btrfs_block_group_cache *
 __btrfs_find_block_group(struct btrfs_root *root,
                         struct btrfs_block_group_cache *hint,
@@ -489,13 +430,11 @@ int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 
        path = btrfs_alloc_path();
        BUG_ON(!path);
-       maybe_lock_mutex(root);
        key.objectid = start;
        key.offset = len;
        btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
        ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
                                0, 0);
-       maybe_unlock_mutex(root);
        btrfs_free_path(path);
        return ret;
 }
@@ -720,8 +659,9 @@ static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 
                BUG_ON(owner_objectid >= BTRFS_MAX_LEVEL);
                num_bytes = btrfs_level_size(root, (int)owner_objectid);
+               mutex_lock(&root->fs_info->extent_ins_mutex);
                if (test_range_bit(&root->fs_info->extent_ins, bytenr,
-                               bytenr + num_bytes - 1, EXTENT_LOCKED, 0)) {
+                               bytenr + num_bytes - 1, EXTENT_WRITEBACK, 0)) {
                        u64 priv;
                        ret = get_state_private(&root->fs_info->extent_ins,
                                                bytenr, &priv);
@@ -730,6 +670,7 @@ static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
                                                        (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;
                } else {
@@ -747,10 +688,11 @@ static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 
                        set_extent_bits(&root->fs_info->extent_ins,
                                        bytenr, bytenr + num_bytes - 1,
-                                       EXTENT_LOCKED, GFP_NOFS);
+                                       EXTENT_WRITEBACK, GFP_NOFS);
                        set_state_private(&root->fs_info->extent_ins,
                                          bytenr, (unsigned long)extent_op);
                }
+               mutex_unlock(&root->fs_info->extent_ins_mutex);
                return 0;
        }
 
@@ -769,8 +711,8 @@ static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
                                    parent, ref_root, ref_generation,
                                    owner_objectid);
        BUG_ON(ret);
-       finish_current_insert(trans, extent_root);
-       del_pending_extents(trans, extent_root);
+       finish_current_insert(trans, extent_root, 0);
+       del_pending_extents(trans, extent_root, 0);
 out:
        btrfs_free_path(path);
        return ret;
@@ -786,12 +728,10 @@ int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
        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);
        return ret;
 }
 
@@ -844,8 +784,8 @@ static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
                                    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);
+       finish_current_insert(trans, root->fs_info->extent_root, 0);
+       del_pending_extents(trans, root->fs_info->extent_root, 0);
 
        btrfs_free_path(path);
        return 0;
@@ -861,19 +801,17 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
        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 btrfs_extent_post_op(struct btrfs_trans_handle *trans,
                         struct btrfs_root *root)
 {
-       finish_current_insert(trans, root->fs_info->extent_root);
-       del_pending_extents(trans, root->fs_info->extent_root);
+       finish_current_insert(trans, root->fs_info->extent_root, 1);
+       del_pending_extents(trans, root->fs_info->extent_root, 1);
        return 0;
 }
 
@@ -930,7 +868,6 @@ static int get_reference_status(struct btrfs_root *root, u64 bytenr,
        key.type = BTRFS_EXTENT_ITEM_KEY;
 
        path = btrfs_alloc_path();
-       mutex_lock(&root->fs_info->alloc_mutex);
        ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
        if (ret < 0)
                goto out;
@@ -997,7 +934,6 @@ static int get_reference_status(struct btrfs_root *root, u64 bytenr,
        }
        ret = 0;
 out:
-       mutex_unlock(&root->fs_info->alloc_mutex);
        btrfs_free_path(path);
        return ret;
 }
@@ -1223,13 +1159,11 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 
                        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);
 
                        if (ret) {
                                faili = i;
@@ -1238,13 +1172,11 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                        }
                } 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);
                        if (ret) {
                                faili = i;
                                WARN_ON(1);
@@ -1314,24 +1246,20 @@ int btrfs_update_ref(struct btrfs_trans_handle *trans,
                        bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
                        if (bytenr == 0)
                                continue;
-                       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;
                }
@@ -1364,8 +1292,8 @@ static int write_one_cache_group(struct btrfs_trans_handle *trans,
        btrfs_mark_buffer_dirty(leaf);
        btrfs_release_path(extent_root, path);
 fail:
-       finish_current_insert(trans, extent_root);
-       pending_ret = del_pending_extents(trans, extent_root);
+       finish_current_insert(trans, extent_root, 0);
+       pending_ret = del_pending_extents(trans, extent_root, 0);
        if (ret)
                return ret;
        if (pending_ret)
@@ -1388,7 +1316,6 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
        if (!path)
                return -ENOMEM;
 
-       mutex_lock(&root->fs_info->alloc_mutex);
        while(1) {
                cache = NULL;
                spin_lock(&root->fs_info->block_group_cache_lock);
@@ -1422,7 +1349,6 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
                }
        }
        btrfs_free_path(path);
-       mutex_unlock(&root->fs_info->alloc_mutex);
        return werr;
 }
 
@@ -1434,9 +1360,11 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
 
        found = __find_space_info(info, flags);
        if (found) {
+               spin_lock(&found->lock);
                found->total_bytes += total_bytes;
                found->bytes_used += bytes_used;
                found->full = 0;
+               spin_unlock(&found->lock);
                *space_info = found;
                return 0;
        }
@@ -1446,6 +1374,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
 
        list_add(&found->list, &info->space_info);
        INIT_LIST_HEAD(&found->block_groups);
+       init_rwsem(&found->groups_sem);
        spin_lock_init(&found->lock);
        found->flags = flags;
        found->total_bytes = total_bytes;
@@ -1522,43 +1451,53 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
        }
        BUG_ON(!space_info);
 
+       spin_lock(&space_info->lock);
        if (space_info->force_alloc) {
                force = 1;
                space_info->force_alloc = 0;
        }
-       if (space_info->full)
+       if (space_info->full) {
+               spin_unlock(&space_info->lock);
                goto out;
+       }
 
        thresh = div_factor(space_info->total_bytes, 6);
        if (!force &&
           (space_info->bytes_used + space_info->bytes_pinned +
-           space_info->bytes_reserved + alloc_bytes) < thresh)
+           space_info->bytes_reserved + alloc_bytes) < thresh) {
+               spin_unlock(&space_info->lock);
                goto out;
+       }
 
-       while (!mutex_trylock(&extent_root->fs_info->chunk_mutex)) {
-               if (!force)
-                       goto out;
-               mutex_unlock(&extent_root->fs_info->alloc_mutex);
-               cond_resched();
-               mutex_lock(&extent_root->fs_info->alloc_mutex);
+       spin_unlock(&space_info->lock);
+
+       ret = mutex_trylock(&extent_root->fs_info->chunk_mutex);
+       if (!ret && !force) {
+               goto out;
+       } else if (!ret) {
+               mutex_lock(&extent_root->fs_info->chunk_mutex);
                waited = 1;
        }
 
-       if (waited && space_info->full)
-               goto out_unlock;
+       if (waited) {
+               spin_lock(&space_info->lock);
+               if (space_info->full) {
+                       spin_unlock(&space_info->lock);
+                       goto out_unlock;
+               }
+               spin_unlock(&space_info->lock);
+       }
 
        ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
-       if (ret == -ENOSPC) {
+       if (ret) {
 printk("space info full %Lu\n", flags);
                space_info->full = 1;
                goto out_unlock;
        }
-       BUG_ON(ret);
 
        ret = btrfs_make_block_group(trans, extent_root, 0, flags,
                     BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
        BUG_ON(ret);
-
 out_unlock:
        mutex_unlock(&extent_root->fs_info->chunk_mutex);
 out:
@@ -1576,7 +1515,6 @@ static int update_block_group(struct btrfs_trans_handle *trans,
        u64 old_val;
        u64 byte_in_group;
 
-       WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
        while(total) {
                cache = btrfs_lookup_block_group(info, bytenr);
                if (!cache) {
@@ -1585,6 +1523,7 @@ static int update_block_group(struct btrfs_trans_handle *trans,
                byte_in_group = bytenr - cache->key.objectid;
                WARN_ON(byte_in_group > cache->key.offset);
 
+               spin_lock(&cache->space_info->lock);
                spin_lock(&cache->lock);
                cache->dirty = 1;
                old_val = btrfs_block_group_used(&cache->item);
@@ -1594,11 +1533,13 @@ static int update_block_group(struct btrfs_trans_handle *trans,
                        cache->space_info->bytes_used += num_bytes;
                        btrfs_set_block_group_used(&cache->item, old_val);
                        spin_unlock(&cache->lock);
+                       spin_unlock(&cache->space_info->lock);
                } else {
                        old_val -= num_bytes;
                        cache->space_info->bytes_used -= num_bytes;
                        btrfs_set_block_group_used(&cache->item, old_val);
                        spin_unlock(&cache->lock);
+                       spin_unlock(&cache->space_info->lock);
                        if (mark_free) {
                                int ret;
                                ret = btrfs_add_free_space(cache, bytenr,
@@ -1631,7 +1572,7 @@ int btrfs_update_pinned_extents(struct btrfs_root *root,
        struct btrfs_block_group_cache *cache;
        struct btrfs_fs_info *fs_info = root->fs_info;
 
-       WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
+       WARN_ON(!mutex_is_locked(&root->fs_info->pinned_mutex));
        if (pin) {
                set_extent_dirty(&fs_info->pinned_extents,
                                bytenr, bytenr + num - 1, GFP_NOFS);
@@ -1645,16 +1586,20 @@ int btrfs_update_pinned_extents(struct btrfs_root *root,
                len = min(num, cache->key.offset -
                          (bytenr - cache->key.objectid));
                if (pin) {
+                       spin_lock(&cache->space_info->lock);
                        spin_lock(&cache->lock);
                        cache->pinned += len;
                        cache->space_info->bytes_pinned += len;
                        spin_unlock(&cache->lock);
+                       spin_unlock(&cache->space_info->lock);
                        fs_info->total_pinned += len;
                } else {
+                       spin_lock(&cache->space_info->lock);
                        spin_lock(&cache->lock);
                        cache->pinned -= len;
                        cache->space_info->bytes_pinned -= len;
                        spin_unlock(&cache->lock);
+                       spin_unlock(&cache->space_info->lock);
                        fs_info->total_pinned -= len;
                }
                bytenr += len;
@@ -1670,23 +1615,23 @@ static int update_reserved_extents(struct btrfs_root *root,
        struct btrfs_block_group_cache *cache;
        struct btrfs_fs_info *fs_info = root->fs_info;
 
-       WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
        while (num > 0) {
                cache = btrfs_lookup_block_group(fs_info, bytenr);
                BUG_ON(!cache);
                len = min(num, cache->key.offset -
                          (bytenr - cache->key.objectid));
+
+               spin_lock(&cache->space_info->lock);
+               spin_lock(&cache->lock);
                if (reserve) {
-                       spin_lock(&cache->lock);
                        cache->reserved += len;
                        cache->space_info->bytes_reserved += len;
-                       spin_unlock(&cache->lock);
                } else {
-                       spin_lock(&cache->lock);
                        cache->reserved -= len;
                        cache->space_info->bytes_reserved -= len;
-                       spin_unlock(&cache->lock);
                }
+               spin_unlock(&cache->lock);
+               spin_unlock(&cache->space_info->lock);
                bytenr += len;
                num -= len;
        }
@@ -1701,6 +1646,7 @@ int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
        struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
        int ret;
 
+       mutex_lock(&root->fs_info->pinned_mutex);
        while(1) {
                ret = find_first_extent_bit(pinned_extents, last,
                                            &start, &end, EXTENT_DIRTY);
@@ -1709,6 +1655,7 @@ int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
                set_extent_dirty(copy, start, end, GFP_NOFS);
                last = end + 1;
        }
+       mutex_unlock(&root->fs_info->pinned_mutex);
        return 0;
 }
 
@@ -1721,7 +1668,7 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
        int ret;
        struct btrfs_block_group_cache *cache;
 
-       mutex_lock(&root->fs_info->alloc_mutex);
+       mutex_lock(&root->fs_info->pinned_mutex);
        while(1) {
                ret = find_first_extent_bit(unpin, 0, &start, &end,
                                            EXTENT_DIRTY);
@@ -1733,21 +1680,22 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
                if (cache->cached)
                        btrfs_add_free_space(cache, start, end - start + 1);
                if (need_resched()) {
-                       mutex_unlock(&root->fs_info->alloc_mutex);
+                       mutex_unlock(&root->fs_info->pinned_mutex);
                        cond_resched();
-                       mutex_lock(&root->fs_info->alloc_mutex);
+                       mutex_lock(&root->fs_info->pinned_mutex);
                }
        }
-       mutex_unlock(&root->fs_info->alloc_mutex);
+       mutex_unlock(&root->fs_info->pinned_mutex);
        return 0;
 }
 
 static int finish_current_insert(struct btrfs_trans_handle *trans,
-                                struct btrfs_root *extent_root)
+                                struct btrfs_root *extent_root, int all)
 {
        u64 start;
        u64 end;
        u64 priv;
+       u64 search = 0;
        struct btrfs_fs_info *info = extent_root->fs_info;
        struct btrfs_path *path;
        struct btrfs_extent_ref *ref;
@@ -1757,20 +1705,37 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
        int ret;
        int err = 0;
 
-       WARN_ON(!mutex_is_locked(&extent_root->fs_info->alloc_mutex));
        btrfs_set_stack_extent_refs(&extent_item, 1);
        path = btrfs_alloc_path();
 
        while(1) {
-               ret = find_first_extent_bit(&info->extent_ins, 0, &start,
-                                           &end, EXTENT_LOCKED);
-               if (ret)
+               mutex_lock(&info->extent_ins_mutex);
+               ret = find_first_extent_bit(&info->extent_ins, search, &start,
+                                           &end, EXTENT_WRITEBACK);
+               if (ret) {
+                       mutex_unlock(&info->extent_ins_mutex);
+                       if (search && all) {
+                               search = 0;
+                               continue;
+                       }
                        break;
+               }
+
+               ret = try_lock_extent(&info->extent_ins, start, end, GFP_NOFS);
+               if (!ret) {
+                       search = end + 1;
+                       mutex_unlock(&info->extent_ins_mutex);
+                       cond_resched();
+                       continue;
+               }
+               BUG_ON(ret < 0);
 
                ret = get_state_private(&info->extent_ins, start, &priv);
                BUG_ON(ret);
                extent_op = (struct pending_extent_op *)(unsigned long)priv;
 
+               mutex_unlock(&info->extent_ins_mutex);
+
                if (extent_op->type == PENDING_EXTENT_INSERT) {
                        key.objectid = start;
                        key.offset = end + 1 - start;
@@ -1779,8 +1744,10 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
                                        &extent_item, sizeof(extent_item));
                        BUG_ON(err);
 
+                       mutex_lock(&info->extent_ins_mutex);
                        clear_extent_bits(&info->extent_ins, start, end,
-                                         EXTENT_LOCKED, GFP_NOFS);
+                                         EXTENT_WRITEBACK, GFP_NOFS);
+                       mutex_unlock(&info->extent_ins_mutex);
 
                        err = insert_extent_backref(trans, extent_root, path,
                                                start, extent_op->parent,
@@ -1796,8 +1763,10 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
                                                extent_op->level, 0);
                        BUG_ON(err);
 
+                       mutex_lock(&info->extent_ins_mutex);
                        clear_extent_bits(&info->extent_ins, start, end,
-                                         EXTENT_LOCKED, GFP_NOFS);
+                                         EXTENT_WRITEBACK, GFP_NOFS);
+                       mutex_unlock(&info->extent_ins_mutex);
 
                        key.objectid = start;
                        key.offset = extent_op->parent;
@@ -1815,12 +1784,13 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
                        BUG_ON(1);
                }
                kfree(extent_op);
+               unlock_extent(&info->extent_ins, start, end, GFP_NOFS);
+               if (all)
+                       search = 0;
+               else
+                       search = end + 1;
 
-               if (need_resched()) {
-                       mutex_unlock(&extent_root->fs_info->alloc_mutex);
-                       cond_resched();
-                       mutex_lock(&extent_root->fs_info->alloc_mutex);
-               }
+               cond_resched();
        }
        btrfs_free_path(path);
        return 0;
@@ -1833,7 +1803,6 @@ static int pin_down_bytes(struct btrfs_trans_handle *trans,
        int err = 0;
        struct extent_buffer *buf;
 
-       WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
        if (is_data)
                goto pinit;
 
@@ -1890,7 +1859,6 @@ static int __free_extent(struct btrfs_trans_handle *trans,
        struct btrfs_extent_item *ei;
        u32 refs;
 
-       WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
        key.objectid = bytenr;
        btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
        key.offset = num_bytes;
@@ -1978,8 +1946,10 @@ static int __free_extent(struct btrfs_trans_handle *trans,
 #endif
 
                if (pin) {
+                       mutex_lock(&root->fs_info->pinned_mutex);
                        ret = pin_down_bytes(trans, root, bytenr, num_bytes,
                                owner_objectid >= BTRFS_FIRST_FREE_OBJECTID);
+                       mutex_unlock(&root->fs_info->pinned_mutex);
                        if (ret > 0)
                                mark_free = 1;
                        BUG_ON(ret < 0);
@@ -1999,6 +1969,7 @@ static int __free_extent(struct btrfs_trans_handle *trans,
                ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
                                      num_to_del);
                BUG_ON(ret);
+               btrfs_release_path(extent_root, path);
                ret = update_block_group(trans, root, bytenr, num_bytes, 0,
                                         mark_free);
                BUG_ON(ret);
@@ -2024,7 +1995,7 @@ static int __free_extent(struct btrfs_trans_handle *trans,
 #endif
        }
        btrfs_free_path(path);
-       finish_current_insert(trans, extent_root);
+       finish_current_insert(trans, extent_root, 0);
        return ret;
 }
 
@@ -2033,74 +2004,98 @@ static int __free_extent(struct btrfs_trans_handle *trans,
  * them from the extent map
  */
 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
-                              btrfs_root *extent_root)
+                              btrfs_root *extent_root, int all)
 {
        int ret;
        int err = 0;
-       int mark_free = 0;
        u64 start;
        u64 end;
        u64 priv;
+       u64 search = 0;
        struct extent_io_tree *pending_del;
        struct extent_io_tree *extent_ins;
        struct pending_extent_op *extent_op;
+       struct btrfs_fs_info *info = extent_root->fs_info;
 
-       WARN_ON(!mutex_is_locked(&extent_root->fs_info->alloc_mutex));
        extent_ins = &extent_root->fs_info->extent_ins;
        pending_del = &extent_root->fs_info->pending_del;
 
        while(1) {
-               ret = find_first_extent_bit(pending_del, 0, &start, &end,
-                                           EXTENT_LOCKED);
-               if (ret)
+               mutex_lock(&info->extent_ins_mutex);
+               ret = find_first_extent_bit(pending_del, search, &start, &end,
+                                           EXTENT_WRITEBACK);
+               if (ret) {
+                       mutex_unlock(&info->extent_ins_mutex);
+                       if (all && search) {
+                               search = 0;
+                               continue;
+                       }
                        break;
+               }
+
+               ret = try_lock_extent(extent_ins, start, end, GFP_NOFS);
+               if (!ret) {
+                       search = end+1;
+                       mutex_unlock(&info->extent_ins_mutex);
+                       cond_resched();
+                       continue;
+               }
+               BUG_ON(ret < 0);
 
                ret = get_state_private(pending_del, start, &priv);
                BUG_ON(ret);
                extent_op = (struct pending_extent_op *)(unsigned long)priv;
 
-               clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
+               clear_extent_bits(pending_del, start, end, EXTENT_WRITEBACK,
                                  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)) {
+                                   EXTENT_WRITEBACK, 0)) {
+                       mutex_unlock(&info->extent_ins_mutex);
 free_extent:
                        ret = __free_extent(trans, extent_root,
                                            start, end + 1 - start,
                                            extent_op->orig_parent,
                                            extent_root->root_key.objectid,
                                            extent_op->orig_generation,
-                                           extent_op->level, 0, mark_free);
+                                           extent_op->level, 1, 0);
                        kfree(extent_op);
                } else {
                        kfree(extent_op);
-                       ret = get_state_private(extent_ins, start, &priv);
+
+                       ret = get_state_private(&info->extent_ins, start,
+                                               &priv);
                        BUG_ON(ret);
                        extent_op = (struct pending_extent_op *)
-                                                       (unsigned long)priv;
+                                               (unsigned long)priv;
+
+                       clear_extent_bits(&info->extent_ins, start, end,
+                                         EXTENT_WRITEBACK, GFP_NOFS);
 
-                       clear_extent_bits(extent_ins, start, end,
-                                         EXTENT_LOCKED, GFP_NOFS);
+                       mutex_unlock(&info->extent_ins_mutex);
 
                        if (extent_op->type == PENDING_BACKREF_UPDATE)
                                goto free_extent;
 
+                       mutex_lock(&extent_root->fs_info->pinned_mutex);
+                       ret = pin_down_bytes(trans, extent_root, start,
+                                            end + 1 - start, 0);
+                       mutex_unlock(&extent_root->fs_info->pinned_mutex);
+
                        ret = update_block_group(trans, extent_root, start,
-                                               end + 1 - start, 0, mark_free);
+                                               end + 1 - start, 0, ret > 0);
+
                        BUG_ON(ret);
                        kfree(extent_op);
                }
                if (ret)
                        err = ret;
+               unlock_extent(extent_ins, start, end, GFP_NOFS);
 
-               if (need_resched()) {
-                       mutex_unlock(&extent_root->fs_info->alloc_mutex);
-                       cond_resched();
-                       mutex_lock(&extent_root->fs_info->alloc_mutex);
-               }
+               if (all)
+                       search = 0;
+               else
+                       search = end + 1;
+               cond_resched();
        }
        return err;
 }
@@ -2134,11 +2129,13 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
                extent_op->orig_generation = ref_generation;
                extent_op->level = (int)owner_objectid;
 
+               mutex_lock(&root->fs_info->extent_ins_mutex);
                set_extent_bits(&root->fs_info->pending_del,
                                bytenr, bytenr + num_bytes - 1,
-                               EXTENT_LOCKED, GFP_NOFS);
+                               EXTENT_WRITEBACK, GFP_NOFS);
                set_state_private(&root->fs_info->pending_del,
                                  bytenr, (unsigned long)extent_op);
+               mutex_unlock(&root->fs_info->extent_ins_mutex);
                return 0;
        }
        /* if metadata always pin */
@@ -2164,8 +2161,8 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
                            root_objectid, ref_generation,
                            owner_objectid, pin, pin == 0);
 
-       finish_current_insert(trans, root->fs_info->extent_root);
-       pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
+       finish_current_insert(trans, root->fs_info->extent_root, 0);
+       pending_ret = del_pending_extents(trans, root->fs_info->extent_root, 0);
        return ret ? ret : pending_ret;
 }
 
@@ -2177,11 +2174,9 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans,
 {
        int ret;
 
-       maybe_lock_mutex(root);
        ret = __btrfs_free_extent(trans, root, bytenr, num_bytes, parent,
                                  root_objectid, ref_generation,
                                  owner_objectid, pin);
-       maybe_unlock_mutex(root);
        return ret;
 }
 
@@ -2208,19 +2203,22 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans,
                                     u64 exclude_start, u64 exclude_nr,
                                     int data)
 {
-       int ret;
-       u64 orig_search_start;
+       int ret = 0;
        struct btrfs_root * root = orig_root->fs_info->extent_root;
-       struct btrfs_fs_info *info = root->fs_info;
        u64 total_needed = num_bytes;
        u64 *last_ptr = NULL;
-       struct btrfs_block_group_cache *block_group;
+       struct btrfs_block_group_cache *block_group = NULL;
        int chunk_alloc_done = 0;
        int empty_cluster = 2 * 1024 * 1024;
        int allowed_chunk_alloc = 0;
+       struct list_head *head = NULL, *cur = NULL;
+       int loop = 0;
+       struct btrfs_space_info *space_info;
 
        WARN_ON(num_bytes < root->sectorsize);
        btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
+       ins->objectid = 0;
+       ins->offset = 0;
 
        if (orig_root->ref_cows || empty_size)
                allowed_chunk_alloc = 1;
@@ -2239,152 +2237,143 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans,
                else
                        empty_size += empty_cluster;
        }
-
        search_start = max(search_start, first_logical_byte(root, 0));
-       orig_search_start = search_start;
-
        search_start = max(search_start, hint_byte);
        total_needed += empty_size;
 
-new_group:
-       block_group = btrfs_lookup_block_group(info, search_start);
-       if (!block_group)
-               block_group = btrfs_lookup_first_block_group(info,
-                                                            search_start);
+       block_group = btrfs_lookup_block_group(root->fs_info, search_start);
+       space_info = __find_space_info(root->fs_info, data);
 
-       /*
-        * Ok this looks a little tricky, buts its really simple.  First if we
-        * didn't find a block group obviously we want to start over.
-        * Secondly, if the block group we found does not match the type we
-        * need, and we have a last_ptr and its not 0, chances are the last
-        * allocation we made was at the end of the block group, so lets go
-        * ahead and skip the looking through the rest of the block groups and
-        * start at the beginning.  This helps with metadata allocations,
-        * since you are likely to have a bunch of data block groups to search
-        * through first before you realize that you need to start over, so go
-        * ahead and start over and save the time.
-        */
-       if (!block_group || (!block_group_bits(block_group, data) &&
-                            last_ptr && *last_ptr)) {
-               if (search_start != orig_search_start) {
-                       if (last_ptr && *last_ptr) {
-                               total_needed += empty_cluster;
-                               *last_ptr = 0;
-                       }
-                       search_start = orig_search_start;
-                       goto new_group;
-               } else if (!chunk_alloc_done && allowed_chunk_alloc) {
-                       ret = do_chunk_alloc(trans, root,
-                                            num_bytes + 2 * 1024 * 1024,
-                                            data, 1);
-                       if (ret < 0)
-                               goto error;
-                       BUG_ON(ret);
-                       chunk_alloc_done = 1;
-                       search_start = orig_search_start;
-                       goto new_group;
-               } else {
-                       ret = -ENOSPC;
-                       goto error;
-               }
-       }
-
-       /*
-        * this is going to seach through all of the existing block groups it
-        * can find, so if we don't find something we need to see if we can
-        * allocate what we need.
-        */
-       ret = find_free_space(root, &block_group, &search_start,
-                             total_needed, data);
-       if (ret == -ENOSPC) {
+       down_read(&space_info->groups_sem);
+       while (1) {
+               struct btrfs_free_space *free_space;
                /*
-                * instead of allocating, start at the original search start
-                * and see if there is something to be found, if not then we
-                * allocate
+                * the only way this happens if our hint points to a block
+                * group thats not of the proper type, while looping this
+                * should never happen
                 */
-               if (search_start != orig_search_start) {
-                       if (last_ptr && *last_ptr) {
-                               *last_ptr = 0;
-                               total_needed += empty_cluster;
-                       }
-                       search_start = orig_search_start;
+               WARN_ON(!block_group);
+               mutex_lock(&block_group->alloc_mutex);
+               if (unlikely(!block_group_bits(block_group, data)))
                        goto new_group;
-               }
 
-               /*
-                * we've already allocated, we're pretty screwed
-                */
-               if (chunk_alloc_done) {
-                       goto error;
-               } else if (!allowed_chunk_alloc && block_group &&
-                          block_group_bits(block_group, data)) {
-                       block_group->space_info->force_alloc = 1;
-                       goto error;
-               } else if (!allowed_chunk_alloc) {
-                       goto error;
+               ret = cache_block_group(root, block_group);
+               if (ret) {
+                       mutex_unlock(&block_group->alloc_mutex);
+                       break;
                }
 
-               ret = do_chunk_alloc(trans, root, num_bytes + 2 * 1024 * 1024,
-                                    data, 1);
-               if (ret < 0)
-                       goto error;
+               if (block_group->ro)
+                       goto new_group;
 
-               BUG_ON(ret);
-               chunk_alloc_done = 1;
-               if (block_group)
-                       search_start = block_group->key.objectid +
+               free_space = btrfs_find_free_space(block_group, search_start,
+                                                  total_needed);
+               if (free_space) {
+                       u64 start = block_group->key.objectid;
+                       u64 end = block_group->key.objectid +
                                block_group->key.offset;
-               else
-                       search_start = orig_search_start;
-               goto new_group;
-       }
 
-       if (ret)
-               goto error;
+                       search_start = stripe_align(root, free_space->offset);
 
-       search_start = stripe_align(root, search_start);
-       ins->objectid = search_start;
-       ins->offset = num_bytes;
+                       /* move on to the next group */
+                       if (search_start + num_bytes >= search_end)
+                               goto new_group;
 
-       if (ins->objectid + num_bytes >= search_end) {
-               search_start = orig_search_start;
-               if (chunk_alloc_done) {
-                       ret = -ENOSPC;
-                       goto error;
+                       /* move on to the next group */
+                       if (search_start + num_bytes > end)
+                               goto new_group;
+
+                       if (exclude_nr > 0 &&
+                           (search_start + num_bytes > exclude_start &&
+                            search_start < exclude_start + exclude_nr)) {
+                               search_start = exclude_start + exclude_nr;
+                               /*
+                                * if search_start is still in this block group
+                                * then we just re-search this block group
+                                */
+                               if (search_start >= start &&
+                                   search_start < end) {
+                                       mutex_unlock(&block_group->alloc_mutex);
+                                       continue;
+                               }
+
+                               /* else we go to the next block group */
+                               goto new_group;
+                       }
+
+                       ins->objectid = search_start;
+                       ins->offset = num_bytes;
+
+                       btrfs_remove_free_space_lock(block_group, search_start,
+                                                    num_bytes);
+                       /* we are all good, lets return */
+                       mutex_unlock(&block_group->alloc_mutex);
+                       break;
                }
-               goto new_group;
-       }
+new_group:
+               mutex_unlock(&block_group->alloc_mutex);
+               /*
+                * Here's how this works.
+                * loop == 0: we were searching a block group via a hint
+                *              and didn't find anything, so we start at
+                *              the head of the block groups and keep searching
+                * loop == 1: we're searching through all of the block groups
+                *              if we hit the head again we have searched
+                *              all of the block groups for this space and we
+                *              need to try and allocate, if we cant error out.
+                * loop == 2: we allocated more space and are looping through
+                *              all of the block groups again.
+                */
+               if (loop == 0) {
+                       head = &space_info->block_groups;
+                       cur = head->next;
 
-       if (ins->objectid + num_bytes >
-           block_group->key.objectid + block_group->key.offset) {
-               if (search_start == orig_search_start && chunk_alloc_done) {
-                       ret = -ENOSPC;
-                       goto error;
+                       if (last_ptr && *last_ptr) {
+                               total_needed += empty_cluster;
+                               *last_ptr = 0;
+                       }
+                       loop++;
+               } else if (loop == 1 && cur == head) {
+                       if (allowed_chunk_alloc && !chunk_alloc_done) {
+                               up_read(&space_info->groups_sem);
+                               ret = do_chunk_alloc(trans, root, num_bytes +
+                                                    2 * 1024 * 1024, data, 1);
+                               if (ret < 0)
+                                       break;
+                               down_read(&space_info->groups_sem);
+                               loop++;
+                               head = &space_info->block_groups;
+                               cur = head->next;
+                               chunk_alloc_done = 1;
+                       } else if (!allowed_chunk_alloc) {
+                               space_info->force_alloc = 1;
+                               break;
+                       } else {
+                               break;
+                       }
+               } else if (cur == head) {
+                       break;
                }
-               search_start = block_group->key.objectid +
-                       block_group->key.offset;
-               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;
-               goto new_group;
+               block_group = list_entry(cur, struct btrfs_block_group_cache,
+                                        list);
+               search_start = block_group->key.objectid;
+               cur = cur->next;
        }
 
-       if (!(data & BTRFS_BLOCK_GROUP_DATA))
-               trans->block_group = block_group;
+       /* we found what we needed */
+       if (ins->objectid) {
+               if (!(data & BTRFS_BLOCK_GROUP_DATA))
+                       trans->block_group = block_group;
 
-       ins->offset = num_bytes;
-       if (last_ptr) {
-               *last_ptr = ins->objectid + ins->offset;
-               if (*last_ptr ==
-                   btrfs_super_total_bytes(&root->fs_info->super_copy))
-                       *last_ptr = 0;
+               if (last_ptr)
+                       *last_ptr = ins->objectid + ins->offset;
+               ret = 0;
+       } else if (!ret) {
+               ret = -ENOSPC;
        }
 
-       ret = 0;
-error:
+       up_read(&space_info->groups_sem);
        return ret;
 }
 
@@ -2397,7 +2386,7 @@ static void dump_space_info(struct btrfs_space_info *info, u64 bytes)
               info->total_bytes - info->bytes_used - info->bytes_pinned -
               info->bytes_reserved, (info->full) ? "" : "not ");
 
-       spin_lock(&info->lock);
+       down_read(&info->groups_sem);
        list_for_each(l, &info->block_groups) {
                cache = list_entry(l, struct btrfs_block_group_cache, list);
                spin_lock(&cache->lock);
@@ -2409,7 +2398,7 @@ static void dump_space_info(struct btrfs_space_info *info, u64 bytes)
                btrfs_dump_free_space(cache, bytes);
                spin_unlock(&cache->lock);
        }
-       spin_unlock(&info->lock);
+       up_read(&info->groups_sem);
 }
 
 static int __btrfs_reserve_extent(struct btrfs_trans_handle *trans,
@@ -2423,7 +2412,6 @@ static int __btrfs_reserve_extent(struct btrfs_trans_handle *trans,
        u64 search_start = 0;
        u64 alloc_profile;
        struct btrfs_fs_info *info = root->fs_info;
-       struct btrfs_block_group_cache *cache;
 
        if (data) {
                alloc_profile = info->avail_data_alloc_bits &
@@ -2479,13 +2467,6 @@ again:
                dump_space_info(sinfo, num_bytes);
                BUG();
        }
-       cache = btrfs_lookup_block_group(root->fs_info, ins->objectid);
-       if (!cache) {
-               printk(KERN_ERR "Unable to find block group for %Lu\n", ins->objectid);
-               return -ENOSPC;
-       }
-
-       ret = btrfs_remove_free_space(cache, ins->objectid, ins->offset);
 
        return ret;
 }
@@ -2494,16 +2475,13 @@ int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
 {
        struct btrfs_block_group_cache *cache;
 
-       maybe_lock_mutex(root);
        cache = btrfs_lookup_block_group(root->fs_info, start);
        if (!cache) {
                printk(KERN_ERR "Unable to find block group for %Lu\n", start);
-               maybe_unlock_mutex(root);
                return -ENOSPC;
        }
        btrfs_add_free_space(cache, start, len);
        update_reserved_extents(root, start, len, 0);
-       maybe_unlock_mutex(root);
        return 0;
 }
 
@@ -2515,12 +2493,10 @@ int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
                                  u64 data)
 {
        int ret;
-       maybe_lock_mutex(root);
        ret = __btrfs_reserve_extent(trans, root, num_bytes, min_alloc_size,
                                     empty_size, hint_byte, search_end, ins,
                                     data);
        update_reserved_extents(root, ins->objectid, ins->offset, 1);
-       maybe_unlock_mutex(root);
        return ret;
 }
 
@@ -2570,11 +2546,13 @@ static int __btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
                extent_op->orig_generation = 0;
                extent_op->level = (int)owner;
 
+               mutex_lock(&root->fs_info->extent_ins_mutex);
                set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
                                ins->objectid + ins->offset - 1,
-                               EXTENT_LOCKED, GFP_NOFS);
+                               EXTENT_WRITEBACK, GFP_NOFS);
                set_state_private(&root->fs_info->extent_ins,
                                  ins->objectid, (unsigned long)extent_op);
+               mutex_unlock(&root->fs_info->extent_ins_mutex);
                goto update_block;
        }
 
@@ -2608,8 +2586,8 @@ static int __btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
        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);
+       finish_current_insert(trans, extent_root, 0);
+       pending_ret = del_pending_extents(trans, extent_root, 0);
 
        if (ret)
                goto out;
@@ -2638,11 +2616,9 @@ int btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
 
        if (root_objectid == BTRFS_TREE_LOG_OBJECTID)
                return 0;
-       maybe_lock_mutex(root);
        ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
                                            ref_generation, owner, ins);
        update_reserved_extents(root, ins->objectid, ins->offset, 0);
-       maybe_unlock_mutex(root);
        return ret;
 }
 
@@ -2659,15 +2635,16 @@ int btrfs_alloc_logged_extent(struct btrfs_trans_handle *trans,
        int ret;
        struct btrfs_block_group_cache *block_group;
 
-       maybe_lock_mutex(root);
        block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
+       mutex_lock(&block_group->alloc_mutex);
        cache_block_group(root, block_group);
 
-       ret = btrfs_remove_free_space(block_group, ins->objectid, ins->offset);
+       ret = btrfs_remove_free_space_lock(block_group, ins->objectid,
+                                          ins->offset);
+       mutex_unlock(&block_group->alloc_mutex);
        BUG_ON(ret);
        ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
                                            ref_generation, owner, ins);
-       maybe_unlock_mutex(root);
        return ret;
 }
 
@@ -2687,8 +2664,6 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
 {
        int ret;
 
-       maybe_lock_mutex(root);
-
        ret = __btrfs_reserve_extent(trans, root, num_bytes,
                                     min_alloc_size, empty_size, hint_byte,
                                     search_end, ins, data);
@@ -2702,7 +2677,6 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
        } else {
                update_reserved_extents(root, ins->objectid, ins->offset, 1);
        }
-       maybe_unlock_mutex(root);
        return ret;
 }
 
@@ -2794,12 +2768,10 @@ int btrfs_drop_leaf_ref(struct btrfs_trans_handle *trans,
                if (disk_bytenr == 0)
                        continue;
 
-               mutex_lock(&root->fs_info->alloc_mutex);
                ret = __btrfs_free_extent(trans, root, disk_bytenr,
                                btrfs_file_extent_disk_num_bytes(leaf, fi),
                                leaf->start, leaf_owner, leaf_generation,
                                key.objectid, 0);
-               mutex_unlock(&root->fs_info->alloc_mutex);
                BUG_ON(ret);
 
                atomic_inc(&root->fs_info->throttle_gen);
@@ -2818,12 +2790,10 @@ static int noinline cache_drop_leaf_ref(struct btrfs_trans_handle *trans,
        struct btrfs_extent_info *info = ref->extents;
 
        for (i = 0; i < ref->nritems; i++) {
-               mutex_lock(&root->fs_info->alloc_mutex);
                ret = __btrfs_free_extent(trans, root, info->bytenr,
                                          info->num_bytes, ref->bytenr,
                                          ref->owner, ref->generation,
                                          info->objectid, 0);
-               mutex_unlock(&root->fs_info->alloc_mutex);
 
                atomic_inc(&root->fs_info->throttle_gen);
                wake_up(&root->fs_info->transaction_throttle);
@@ -2935,13 +2905,11 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
                        root_gen = btrfs_header_generation(parent);
                        path->slots[*level]++;
 
-                       mutex_lock(&root->fs_info->alloc_mutex);
                        ret = __btrfs_free_extent(trans, root, bytenr,
                                                blocksize, parent->start,
                                                root_owner, root_gen,
                                                *level - 1, 1);
                        BUG_ON(ret);
-                       mutex_unlock(&root->fs_info->alloc_mutex);
 
                        atomic_inc(&root->fs_info->throttle_gen);
                        wake_up(&root->fs_info->transaction_throttle);
@@ -3017,11 +2985,9 @@ out:
        root_owner = btrfs_header_owner(parent);
        root_gen = btrfs_header_generation(parent);
 
-       mutex_lock(&root->fs_info->alloc_mutex);
        ret = __btrfs_free_extent(trans, root, bytenr, blocksize,
                                  parent->start, root_owner, root_gen,
                                  *level, 1);
-       mutex_unlock(&root->fs_info->alloc_mutex);
        free_extent_buffer(path->nodes[*level]);
        path->nodes[*level] = NULL;
        *level += 1;
@@ -3031,6 +2997,95 @@ out:
        return 0;
 }
 
+/*
+ * helper function for drop_subtree, this function is similar to
+ * walk_down_tree. The main difference is that it checks reference
+ * counts while tree blocks are locked.
+ */
+static int noinline walk_down_subtree(struct btrfs_trans_handle *trans,
+                                     struct btrfs_root *root,
+                                     struct btrfs_path *path, int *level)
+{
+       struct extent_buffer *next;
+       struct extent_buffer *cur;
+       struct extent_buffer *parent;
+       u64 bytenr;
+       u64 ptr_gen;
+       u32 blocksize;
+       u32 refs;
+       int ret;
+
+       cur = path->nodes[*level];
+       ret = btrfs_lookup_extent_ref(trans, root, cur->start, cur->len,
+                                     &refs);
+       BUG_ON(ret);
+       if (refs > 1)
+               goto out;
+
+       while (*level >= 0) {
+               cur = path->nodes[*level];
+               if (*level == 0) {
+                       ret = btrfs_drop_leaf_ref(trans, root, cur);
+                       BUG_ON(ret);
+                       clean_tree_block(trans, root, cur);
+                       break;
+               }
+               if (path->slots[*level] >= btrfs_header_nritems(cur)) {
+                       clean_tree_block(trans, root, cur);
+                       break;
+               }
+
+               bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
+               blocksize = btrfs_level_size(root, *level - 1);
+               ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
+
+               next = read_tree_block(root, bytenr, blocksize, ptr_gen);
+               btrfs_tree_lock(next);
+
+               ret = btrfs_lookup_extent_ref(trans, root, bytenr, blocksize,
+                                             &refs);
+               BUG_ON(ret);
+               if (refs > 1) {
+                       parent = path->nodes[*level];
+                       ret = btrfs_free_extent(trans, root, bytenr,
+                                       blocksize, parent->start,
+                                       btrfs_header_owner(parent),
+                                       btrfs_header_generation(parent),
+                                       *level - 1, 1);
+                       BUG_ON(ret);
+                       path->slots[*level]++;
+                       btrfs_tree_unlock(next);
+                       free_extent_buffer(next);
+                       continue;
+               }
+
+               *level = btrfs_header_level(next);
+               path->nodes[*level] = next;
+               path->slots[*level] = 0;
+               path->locks[*level] = 1;
+               cond_resched();
+       }
+out:
+       parent = path->nodes[*level + 1];
+       bytenr = path->nodes[*level]->start;
+       blocksize = path->nodes[*level]->len;
+
+       ret = btrfs_free_extent(trans, root, bytenr, blocksize,
+                       parent->start, btrfs_header_owner(parent),
+                       btrfs_header_generation(parent), *level, 1);
+       BUG_ON(ret);
+
+       if (path->locks[*level]) {
+               btrfs_tree_unlock(path->nodes[*level]);
+               path->locks[*level] = 0;
+       }
+       free_extent_buffer(path->nodes[*level]);
+       path->nodes[*level] = NULL;
+       *level += 1;
+       cond_resched();
+       return 0;
+}
+
 /*
  * helper for dropping snapshots.  This walks back up the tree in the path
  * to find the first node higher up where we haven't yet gone through
@@ -3038,7 +3093,8 @@ out:
  */
 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
                                 struct btrfs_root *root,
-                                struct btrfs_path *path, int *level)
+                                struct btrfs_path *path,
+                                int *level, int max_level)
 {
        u64 root_owner;
        u64 root_gen;
@@ -3047,7 +3103,7 @@ static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
        int slot;
        int ret;
 
-       for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
+       for (i = *level; i < max_level && path->nodes[i]; i++) {
                slot = path->slots[i];
                if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
                        struct extent_buffer *node;
@@ -3070,12 +3126,18 @@ static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
 
                        root_owner = btrfs_header_owner(parent);
                        root_gen = btrfs_header_generation(parent);
+
+                       clean_tree_block(trans, root, path->nodes[*level]);
                        ret = btrfs_free_extent(trans, root,
                                                path->nodes[*level]->start,
                                                path->nodes[*level]->len,
                                                parent->start, root_owner,
                                                root_gen, *level, 1);
                        BUG_ON(ret);
+                       if (path->locks[*level]) {
+                               btrfs_tree_unlock(path->nodes[*level]);
+                               path->locks[*level] = 0;
+                       }
                        free_extent_buffer(path->nodes[*level]);
                        path->nodes[*level] = NULL;
                        *level = i + 1;
@@ -3145,7 +3207,8 @@ int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
                if (wret < 0)
                        ret = wret;
 
-               wret = walk_up_tree(trans, root, path, &level);
+               wret = walk_up_tree(trans, root, path, &level,
+                                   BTRFS_MAX_LEVEL);
                if (wret > 0)
                        break;
                if (wret < 0)
@@ -3168,6 +3231,50 @@ out:
        return ret;
 }
 
+int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
+                       struct btrfs_root *root,
+                       struct extent_buffer *node,
+                       struct extent_buffer *parent)
+{
+       struct btrfs_path *path;
+       int level;
+       int parent_level;
+       int ret = 0;
+       int wret;
+
+       path = btrfs_alloc_path();
+       BUG_ON(!path);
+
+       BUG_ON(!btrfs_tree_locked(parent));
+       parent_level = btrfs_header_level(parent);
+       extent_buffer_get(parent);
+       path->nodes[parent_level] = parent;
+       path->slots[parent_level] = btrfs_header_nritems(parent);
+
+       BUG_ON(!btrfs_tree_locked(node));
+       level = btrfs_header_level(node);
+       extent_buffer_get(node);
+       path->nodes[level] = node;
+       path->slots[level] = 0;
+
+       while (1) {
+               wret = walk_down_subtree(trans, root, path, &level);
+               if (wret < 0)
+                       ret = wret;
+               if (wret != 0)
+                       break;
+
+               wret = walk_up_tree(trans, root, path, &level, parent_level);
+               if (wret < 0)
+                       ret = wret;
+               if (wret != 0)
+                       break;
+       }
+
+       btrfs_free_path(path);
+       return ret;
+}
+
 static unsigned long calc_ra(unsigned long start, unsigned long last,
                             unsigned long nr)
 {
@@ -3278,6 +3385,7 @@ static int noinline relocate_data_extent(struct inode *reloc_inode,
 
        em->start = extent_key->objectid - offset;
        em->len = extent_key->offset;
+       em->block_len = extent_key->offset;
        em->block_start = extent_key->objectid;
        em->bdev = root->fs_info->fs_devices->latest_bdev;
        set_bit(EXTENT_FLAG_PINNED, &em->flags);
@@ -3311,13 +3419,21 @@ struct btrfs_ref_path {
        u32 num_refs;
        int lowest_level;
        int current_level;
+       int shared_level;
+
+       struct btrfs_key node_keys[BTRFS_MAX_LEVEL];
+       u64 new_nodes[BTRFS_MAX_LEVEL];
 };
 
 struct disk_extent {
+       u64 ram_bytes;
        u64 disk_bytenr;
        u64 disk_num_bytes;
        u64 offset;
        u64 num_bytes;
+       u8 compression;
+       u8 encryption;
+       u16 other_encoding;
 };
 
 static int is_cowonly_root(u64 root_objectid)
@@ -3350,11 +3466,10 @@ static int noinline __next_ref_path(struct btrfs_trans_handle *trans,
        if (!path)
                return -ENOMEM;
 
-       mutex_lock(&extent_root->fs_info->alloc_mutex);
-
        if (first_time) {
                ref_path->lowest_level = -1;
                ref_path->current_level = -1;
+               ref_path->shared_level = -1;
                goto walk_up;
        }
 walk_down:
@@ -3398,15 +3513,16 @@ walk_down:
 
                btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
                if (found_key.objectid == bytenr &&
-                               found_key.type == BTRFS_EXTENT_REF_KEY)
+                   found_key.type == BTRFS_EXTENT_REF_KEY) {
+                       if (level < ref_path->shared_level)
+                               ref_path->shared_level = level;
                        goto found;
+               }
 next:
                level--;
                btrfs_release_path(extent_root, path);
                if (need_resched()) {
-                       mutex_unlock(&extent_root->fs_info->alloc_mutex);
                        cond_resched();
-                       mutex_lock(&extent_root->fs_info->alloc_mutex);
                }
        }
        /* reached lowest level */
@@ -3519,15 +3635,12 @@ found:
 
                btrfs_release_path(extent_root, path);
                if (need_resched()) {
-                       mutex_unlock(&extent_root->fs_info->alloc_mutex);
                        cond_resched();
-                       mutex_lock(&extent_root->fs_info->alloc_mutex);
                }
        }
        /* reached max tree level, but no tree root found. */
        BUG();
 out:
-       mutex_unlock(&extent_root->fs_info->alloc_mutex);
        btrfs_free_path(path);
        return ret;
 }
@@ -3631,6 +3744,11 @@ static int noinline get_new_locations(struct inode *reloc_inode,
                        btrfs_file_extent_disk_num_bytes(leaf, fi);
                exts[nr].offset = btrfs_file_extent_offset(leaf, fi);
                exts[nr].num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
+               exts[nr].ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
+               exts[nr].compression = btrfs_file_extent_compression(leaf, fi);
+               exts[nr].encryption = btrfs_file_extent_encryption(leaf, fi);
+               exts[nr].other_encoding = btrfs_file_extent_other_encoding(leaf,
+                                                                          fi);
                WARN_ON(exts[nr].offset > 0);
                WARN_ON(exts[nr].num_bytes != exts[nr].disk_num_bytes);
 
@@ -3846,6 +3964,8 @@ next:
                                                new_extents[0].disk_bytenr);
                        btrfs_set_file_extent_disk_num_bytes(leaf, fi,
                                                new_extents[0].disk_num_bytes);
+                       btrfs_set_file_extent_ram_bytes(leaf, fi,
+                                               new_extents[0].ram_bytes);
                        ext_offset += new_extents[0].offset;
                        btrfs_set_file_extent_offset(leaf, fi, ext_offset);
                        btrfs_mark_buffer_dirty(leaf);
@@ -3911,6 +4031,16 @@ next:
                                                new_extents[i].disk_bytenr);
                                btrfs_set_file_extent_disk_num_bytes(leaf, fi,
                                                new_extents[i].disk_num_bytes);
+                               btrfs_set_file_extent_ram_bytes(leaf, fi,
+                                               new_extents[i].ram_bytes);
+
+                               btrfs_set_file_extent_compression(leaf, fi,
+                                               new_extents[i].compression);
+                               btrfs_set_file_extent_encryption(leaf, fi,
+                                               new_extents[i].encryption);
+                               btrfs_set_file_extent_other_encoding(leaf, fi,
+                                               new_extents[i].other_encoding);
+
                                btrfs_set_file_extent_num_bytes(leaf, fi,
                                                        extent_len);
                                ext_offset += new_extents[i].offset;
@@ -3970,51 +4100,6 @@ out:
        return ret;
 }
 
-int btrfs_add_reloc_mapping(struct btrfs_root *root, u64 orig_bytenr,
-                           u64 num_bytes, u64 new_bytenr)
-{
-       set_extent_bits(&root->fs_info->reloc_mapping_tree,
-                       orig_bytenr, orig_bytenr + num_bytes - 1,
-                       EXTENT_LOCKED, GFP_NOFS);
-       set_state_private(&root->fs_info->reloc_mapping_tree,
-                         orig_bytenr, new_bytenr);
-       return 0;
-}
-
-int btrfs_get_reloc_mapping(struct btrfs_root *root, u64 orig_bytenr,
-                           u64 num_bytes, u64 *new_bytenr)
-{
-       u64 bytenr;
-       u64 cur_bytenr = orig_bytenr;
-       u64 prev_bytenr = orig_bytenr;
-       int ret;
-
-       while (1) {
-               ret = get_state_private(&root->fs_info->reloc_mapping_tree,
-                                       cur_bytenr, &bytenr);
-               if (ret)
-                       break;
-               prev_bytenr = cur_bytenr;
-               cur_bytenr = bytenr;
-       }
-
-       if (orig_bytenr == cur_bytenr)
-               return -ENOENT;
-
-       if (prev_bytenr != orig_bytenr) {
-               set_state_private(&root->fs_info->reloc_mapping_tree,
-                                 orig_bytenr, cur_bytenr);
-       }
-       *new_bytenr = cur_bytenr;
-       return 0;
-}
-
-void btrfs_free_reloc_mappings(struct btrfs_root *root)
-{
-       clear_extent_bits(&root->fs_info->reloc_mapping_tree,
-                         0, (u64)-1, -1, GFP_NOFS);
-}
-
 int btrfs_reloc_tree_cache_ref(struct btrfs_trans_handle *trans,
                               struct btrfs_root *root,
                               struct extent_buffer *buf, u64 orig_start)
@@ -4169,6 +4254,8 @@ static int noinline replace_extents_in_leaf(struct btrfs_trans_handle *trans,
                ref->extents[ext_index].num_bytes = new_extent->disk_num_bytes;
 
                btrfs_set_file_extent_generation(leaf, fi, trans->transid);
+               btrfs_set_file_extent_ram_bytes(leaf, fi,
+                                               new_extent->ram_bytes);
                btrfs_set_file_extent_disk_bytenr(leaf, fi,
                                                new_extent->disk_bytenr);
                btrfs_set_file_extent_disk_num_bytes(leaf, fi,
@@ -4198,15 +4285,30 @@ static int noinline replace_extents_in_leaf(struct btrfs_trans_handle *trans,
        return 0;
 }
 
-int btrfs_free_reloc_root(struct btrfs_root *root)
+int btrfs_free_reloc_root(struct btrfs_trans_handle *trans,
+                         struct btrfs_root *root)
 {
        struct btrfs_root *reloc_root;
+       int ret;
 
        if (root->reloc_root) {
                reloc_root = root->reloc_root;
                root->reloc_root = NULL;
                list_add(&reloc_root->dead_list,
                         &root->fs_info->dead_reloc_roots);
+
+               btrfs_set_root_bytenr(&reloc_root->root_item,
+                                     reloc_root->node->start);
+               btrfs_set_root_level(&root->root_item,
+                                    btrfs_header_level(reloc_root->node));
+               memset(&reloc_root->root_item.drop_progress, 0,
+                       sizeof(struct btrfs_disk_key));
+               reloc_root->root_item.drop_level = 0;
+
+               ret = btrfs_update_root(trans, root->fs_info->tree_root,
+                                       &reloc_root->root_key,
+                                       &reloc_root->root_item);
+               BUG_ON(ret);
        }
        return 0;
 }
@@ -4332,8 +4434,7 @@ static int noinline init_reloc_tree(struct btrfs_trans_handle *trans,
        btrfs_set_root_refs(root_item, 0);
        btrfs_set_root_bytenr(root_item, eb->start);
        btrfs_set_root_level(root_item, btrfs_header_level(eb));
-       memset(&root_item->drop_progress, 0, sizeof(root_item->drop_progress));
-       root_item->drop_level = 0;
+       btrfs_set_root_generation(root_item, trans->transid);
 
        btrfs_tree_unlock(eb);
        free_extent_buffer(eb);
@@ -4358,15 +4459,19 @@ static int noinline init_reloc_tree(struct btrfs_trans_handle *trans,
  * Core function of space balance.
  *
  * The idea is using reloc trees to relocate tree blocks in reference
- * counted roots. There is one reloc tree for each subvol, all reloc
- * trees share same key objectid. Reloc trees are snapshots of the
- * latest committed roots (subvol root->commit_root). To relocate a tree
- * block referenced by a subvol, the code COW the block through the reloc
- * tree, then update pointer in the subvol to point to the new block.
- * Since all reloc trees share same key objectid, we can easily do special
- * handing to share tree blocks between reloc trees. Once a tree block has
- * been COWed in one reloc tree, we can use the result when the same block
- * is COWed again through other reloc trees.
+ * counted roots. There is one reloc tree for each subvol, and all
+ * reloc trees share same root key objectid. Reloc trees are snapshots
+ * of the latest committed roots of subvols (root->commit_root).
+ *
+ * To relocate a tree block referenced by a subvol, there are two steps.
+ * COW the block through subvol's reloc tree, then update block pointer
+ * in the subvol to point to the new block. Since all reloc trees share
+ * same root key objectid, doing special handing for tree blocks owned
+ * by them is easy. Once a tree block has been COWed in one reloc tree,
+ * we can use the resulting new block directly when the same block is
+ * required to COW again through other reloc trees. By this way, relocated
+ * tree blocks are shared between reloc trees, so they are also shared
+ * between subvols.
  */
 static int noinline relocate_one_path(struct btrfs_trans_handle *trans,
                                      struct btrfs_root *root,
@@ -4381,15 +4486,14 @@ static int noinline relocate_one_path(struct btrfs_trans_handle *trans,
        struct btrfs_key *keys;
        u64 *nodes;
        int level;
-       int lowest_merge;
+       int shared_level;
        int lowest_level = 0;
-       int update_refs;
        int ret;
 
        if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
                lowest_level = ref_path->owner_objectid;
 
-       if (is_cowonly_root(ref_path->root_objectid)) {
+       if (!root->ref_cows) {
                path->lowest_level = lowest_level;
                ret = btrfs_search_slot(trans, root, first_key, path, 0, 1);
                BUG_ON(ret < 0);
@@ -4398,91 +4502,49 @@ static int noinline relocate_one_path(struct btrfs_trans_handle *trans,
                return 0;
        }
 
-       keys = kzalloc(sizeof(*keys) * BTRFS_MAX_LEVEL, GFP_NOFS);
-       BUG_ON(!keys);
-       nodes = kzalloc(sizeof(*nodes) * BTRFS_MAX_LEVEL, GFP_NOFS);
-       BUG_ON(!nodes);
-
        mutex_lock(&root->fs_info->tree_reloc_mutex);
        ret = init_reloc_tree(trans, root);
        BUG_ON(ret);
        reloc_root = root->reloc_root;
 
-       path->lowest_level = lowest_level;
-       ret = btrfs_search_slot(trans, reloc_root, first_key, path, 0, 0);
-       BUG_ON(ret);
-       /*
-        * get relocation mapping for tree blocks in the path
-        */
-       lowest_merge = BTRFS_MAX_LEVEL;
-       for (level = BTRFS_MAX_LEVEL - 1; level >= lowest_level; level--) {
-               u64 new_bytenr;
-               eb = path->nodes[level];
-               if (!eb || eb == reloc_root->node)
-                       continue;
-               ret = btrfs_get_reloc_mapping(reloc_root, eb->start, eb->len,
-                                             &new_bytenr);
-               if (ret)
-                       continue;
-               if (level == 0)
-                       btrfs_item_key_to_cpu(eb, &keys[level], 0);
-               else
-                       btrfs_node_key_to_cpu(eb, &keys[level], 0);
-               nodes[level] = new_bytenr;
-               lowest_merge = level;
-       }
+       shared_level = ref_path->shared_level;
+       ref_path->shared_level = BTRFS_MAX_LEVEL - 1;
 
-       update_refs = 0;
-       if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
-               eb = path->nodes[0];
-               if (btrfs_header_generation(eb) < trans->transid)
-                       update_refs = 1;
-       }
+       keys = ref_path->node_keys;
+       nodes = ref_path->new_nodes;
+       memset(&keys[shared_level + 1], 0,
+              sizeof(*keys) * (BTRFS_MAX_LEVEL - shared_level - 1));
+       memset(&nodes[shared_level + 1], 0,
+              sizeof(*nodes) * (BTRFS_MAX_LEVEL - shared_level - 1));
 
-       btrfs_release_path(reloc_root, path);
-       /*
-        * merge tree blocks that already relocated in other reloc trees
-        */
-       if (lowest_merge != BTRFS_MAX_LEVEL) {
+       if (nodes[lowest_level] == 0) {
+               path->lowest_level = lowest_level;
+               ret = btrfs_search_slot(trans, reloc_root, first_key, path,
+                                       0, 1);
+               BUG_ON(ret);
+               for (level = lowest_level; level < BTRFS_MAX_LEVEL; level++) {
+                       eb = path->nodes[level];
+                       if (!eb || eb == reloc_root->node)
+                               break;
+                       nodes[level] = eb->start;
+                       if (level == 0)
+                               btrfs_item_key_to_cpu(eb, &keys[level], 0);
+                       else
+                               btrfs_node_key_to_cpu(eb, &keys[level], 0);
+               }
+               if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
+                       eb = path->nodes[0];
+                       ret = replace_extents_in_leaf(trans, reloc_root, eb,
+                                                     group, reloc_inode);
+                       BUG_ON(ret);
+               }
+               btrfs_release_path(reloc_root, path);
+       } else {
                ret = btrfs_merge_path(trans, reloc_root, keys, nodes,
-                                      lowest_merge);
-               BUG_ON(ret < 0);
-       }
-       /*
-        * cow any tree blocks that still haven't been relocated
-        */
-       ret = btrfs_search_slot(trans, reloc_root, first_key, path, 0, 1);
-       BUG_ON(ret);
-       /*
-        * if we are relocating data block group, update extent pointers
-        * in the newly created tree leaf.
-        */
-       eb = path->nodes[0];
-       if (update_refs && nodes[0] != eb->start) {
-               ret = replace_extents_in_leaf(trans, reloc_root, eb, group,
-                                             reloc_inode);
+                                      lowest_level);
                BUG_ON(ret);
        }
 
-       memset(keys, 0, sizeof(*keys) * BTRFS_MAX_LEVEL);
-       memset(nodes, 0, sizeof(*nodes) * BTRFS_MAX_LEVEL);
-       for (level = BTRFS_MAX_LEVEL - 1; level >= lowest_level; level--) {
-               eb = path->nodes[level];
-               if (!eb || eb == reloc_root->node)
-                       continue;
-               BUG_ON(btrfs_header_owner(eb) != BTRFS_TREE_RELOC_OBJECTID);
-               nodes[level] = eb->start;
-               if (level == 0)
-                       btrfs_item_key_to_cpu(eb, &keys[level], 0);
-               else
-                       btrfs_node_key_to_cpu(eb, &keys[level], 0);
-       }
-
-       if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
-               eb = path->nodes[0];
-               extent_buffer_get(eb);
-       }
-       btrfs_release_path(reloc_root, path);
        /*
         * replace tree blocks in the fs tree with tree blocks in
         * the reloc tree.
@@ -4491,15 +4553,19 @@ static int noinline relocate_one_path(struct btrfs_trans_handle *trans,
        BUG_ON(ret < 0);
 
        if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
+               ret = btrfs_search_slot(trans, reloc_root, first_key, path,
+                                       0, 0);
+               BUG_ON(ret);
+               extent_buffer_get(path->nodes[0]);
+               eb = path->nodes[0];
+               btrfs_release_path(reloc_root, path);
                ret = invalidate_extent_cache(reloc_root, eb, group, root);
                BUG_ON(ret);
                free_extent_buffer(eb);
        }
-       mutex_unlock(&root->fs_info->tree_reloc_mutex);
 
+       mutex_unlock(&root->fs_info->tree_reloc_mutex);
        path->lowest_level = 0;
-       kfree(nodes);
-       kfree(keys);
        return 0;
 }
 
@@ -4510,14 +4576,6 @@ static int noinline relocate_tree_block(struct btrfs_trans_handle *trans,
                                        struct btrfs_ref_path *ref_path)
 {
        int ret;
-       int needs_lock = 0;
-
-       if (root == root->fs_info->extent_root ||
-           root == root->fs_info->chunk_root ||
-           root == root->fs_info->dev_root) {
-               needs_lock = 1;
-               mutex_lock(&root->fs_info->alloc_mutex);
-       }
 
        ret = relocate_one_path(trans, root, path, first_key,
                                ref_path, NULL, NULL);
@@ -4525,8 +4583,6 @@ static int noinline relocate_tree_block(struct btrfs_trans_handle *trans,
 
        if (root == root->fs_info->extent_root)
                btrfs_extent_post_op(trans, root);
-       if (needs_lock)
-               mutex_unlock(&root->fs_info->alloc_mutex);
 
        return 0;
 }
@@ -4538,14 +4594,12 @@ static int noinline del_extent_zero(struct btrfs_trans_handle *trans,
 {
        int ret;
 
-       mutex_lock(&extent_root->fs_info->alloc_mutex);
        ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
        if (ret)
                goto out;
        ret = btrfs_del_item(trans, extent_root, path);
 out:
        btrfs_release_path(extent_root, path);
-       mutex_unlock(&extent_root->fs_info->alloc_mutex);
        return ret;
 }
 
@@ -4581,7 +4635,6 @@ static int noinline relocate_one_extent(struct btrfs_root *extent_root,
        struct btrfs_key first_key;
        u64 prev_block = 0;
 
-       mutex_unlock(&extent_root->fs_info->alloc_mutex);
 
        trans = btrfs_start_transaction(extent_root, 1);
        BUG_ON(!trans);
@@ -4708,7 +4761,6 @@ out:
        btrfs_end_transaction(trans, extent_root);
        kfree(new_extents);
        kfree(ref_path);
-       mutex_lock(&extent_root->fs_info->alloc_mutex);
        return ret;
 }
 
@@ -4761,10 +4813,8 @@ int __alloc_chunk_for_shrink(struct btrfs_root *root,
        spin_lock(&shrink_block_group->lock);
        if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
                spin_unlock(&shrink_block_group->lock);
-               mutex_unlock(&root->fs_info->alloc_mutex);
 
                trans = btrfs_start_transaction(root, 1);
-               mutex_lock(&root->fs_info->alloc_mutex);
                spin_lock(&shrink_block_group->lock);
 
                new_alloc_flags = update_block_group_flags(root,
@@ -4780,9 +4830,7 @@ int __alloc_chunk_for_shrink(struct btrfs_root *root,
                do_chunk_alloc(trans, root->fs_info->extent_root,
                               calc + 2 * 1024 * 1024, new_alloc_flags, force);
 
-               mutex_unlock(&root->fs_info->alloc_mutex);
                btrfs_end_transaction(trans, root);
-               mutex_lock(&root->fs_info->alloc_mutex);
        } else
                spin_unlock(&shrink_block_group->lock);
        return 0;
@@ -4847,7 +4895,8 @@ static struct inode noinline *create_reloc_inode(struct btrfs_fs_info *fs_info,
        BUG_ON(err);
 
        err = btrfs_insert_file_extent(trans, root, objectid, 0, 0, 0,
-                                      group->key.offset, 0);
+                                      group->key.offset, 0, group->key.offset,
+                                      0, 0, 0);
        BUG_ON(err);
 
        inode = btrfs_iget_locked(root->fs_info->sb, objectid, root);
@@ -4905,14 +4954,10 @@ int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start)
        reloc_inode = create_reloc_inode(info, block_group);
        BUG_ON(IS_ERR(reloc_inode));
 
-       mutex_lock(&root->fs_info->alloc_mutex);
-
        __alloc_chunk_for_shrink(root, block_group, 1);
        block_group->ro = 1;
        block_group->space_info->total_bytes -= block_group->key.offset;
 
-       mutex_unlock(&root->fs_info->alloc_mutex);
-
        btrfs_start_delalloc_inodes(info->tree_root);
        btrfs_wait_ordered_extents(info->tree_root, 0);
 again:
@@ -4931,8 +4976,6 @@ again:
        btrfs_remove_leaf_refs(info->tree_root, (u64)-1, 1);
        mutex_unlock(&root->fs_info->cleaner_mutex);
 
-       mutex_lock(&root->fs_info->alloc_mutex);
-
        while(1) {
                ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
                if (ret < 0)
@@ -4960,9 +5003,7 @@ next:
 
                if (progress && need_resched()) {
                        btrfs_release_path(root, path);
-                       mutex_unlock(&root->fs_info->alloc_mutex);
                        cond_resched();
-                       mutex_lock(&root->fs_info->alloc_mutex);
                        progress = 0;
                        continue;
                }
@@ -4989,7 +5030,6 @@ next:
        }
 
        btrfs_release_path(root, path);
-       mutex_unlock(&root->fs_info->alloc_mutex);
 
        if (pass == 0) {
                btrfs_wait_ordered_range(reloc_inode, 0, (u64)-1);
@@ -5011,8 +5051,6 @@ next:
        trans = btrfs_start_transaction(info->tree_root, 1);
        btrfs_commit_transaction(trans, info->tree_root);
 
-       mutex_lock(&root->fs_info->alloc_mutex);
-
        spin_lock(&block_group->lock);
        WARN_ON(block_group->pinned > 0);
        WARN_ON(block_group->reserved > 0);
@@ -5020,7 +5058,6 @@ next:
        spin_unlock(&block_group->lock);
        ret = 0;
 out:
-       mutex_unlock(&root->fs_info->alloc_mutex);
        btrfs_free_path(path);
        return ret;
 }
@@ -5067,7 +5104,6 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
        struct btrfs_block_group_cache *block_group;
        struct rb_node *n;
 
-       mutex_lock(&info->alloc_mutex);
        spin_lock(&info->block_group_cache_lock);
        while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
                block_group = rb_entry(n, struct btrfs_block_group_cache,
@@ -5079,13 +5115,12 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
 
                rb_erase(&block_group->cache_node,
                         &info->block_group_cache_tree);
-               spin_lock(&block_group->space_info->lock);
+               down_write(&block_group->space_info->groups_sem);
                list_del(&block_group->list);
-               spin_unlock(&block_group->space_info->lock);
+               up_write(&block_group->space_info->groups_sem);
                kfree(block_group);
        }
        spin_unlock(&info->block_group_cache_lock);
-       mutex_unlock(&info->alloc_mutex);
        return 0;
 }
 
@@ -5108,7 +5143,6 @@ int btrfs_read_block_groups(struct btrfs_root *root)
        if (!path)
                return -ENOMEM;
 
-       mutex_lock(&root->fs_info->alloc_mutex);
        while(1) {
                ret = find_first_block_group(root, path, &key);
                if (ret > 0) {
@@ -5127,6 +5161,7 @@ int btrfs_read_block_groups(struct btrfs_root *root)
                }
 
                spin_lock_init(&cache->lock);
+               mutex_init(&cache->alloc_mutex);
                INIT_LIST_HEAD(&cache->list);
                read_extent_buffer(leaf, &cache->item,
                                   btrfs_item_ptr_offset(leaf, path->slots[0]),
@@ -5142,9 +5177,9 @@ int btrfs_read_block_groups(struct btrfs_root *root)
                                        &space_info);
                BUG_ON(ret);
                cache->space_info = space_info;
-               spin_lock(&space_info->lock);
-               list_add(&cache->list, &space_info->block_groups);
-               spin_unlock(&space_info->lock);
+               down_write(&space_info->groups_sem);
+               list_add_tail(&cache->list, &space_info->block_groups);
+               up_write(&space_info->groups_sem);
 
                ret = btrfs_add_block_group_cache(root->fs_info, cache);
                BUG_ON(ret);
@@ -5154,7 +5189,6 @@ int btrfs_read_block_groups(struct btrfs_root *root)
        ret = 0;
 error:
        btrfs_free_path(path);
-       mutex_unlock(&root->fs_info->alloc_mutex);
        return ret;
 }
 
@@ -5167,7 +5201,6 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
        struct btrfs_root *extent_root;
        struct btrfs_block_group_cache *cache;
 
-       WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
        extent_root = root->fs_info->extent_root;
 
        root->fs_info->last_trans_new_blockgroup = trans->transid;
@@ -5179,6 +5212,7 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
        cache->key.objectid = chunk_offset;
        cache->key.offset = size;
        spin_lock_init(&cache->lock);
+       mutex_init(&cache->alloc_mutex);
        INIT_LIST_HEAD(&cache->list);
        btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
 
@@ -5190,9 +5224,9 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
        ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
                                &cache->space_info);
        BUG_ON(ret);
-       spin_lock(&cache->space_info->lock);
-       list_add(&cache->list, &cache->space_info->block_groups);
-       spin_unlock(&cache->space_info->lock);
+       down_write(&cache->space_info->groups_sem);
+       list_add_tail(&cache->list, &cache->space_info->block_groups);
+       up_write(&cache->space_info->groups_sem);
 
        ret = btrfs_add_block_group_cache(root->fs_info, cache);
        BUG_ON(ret);
@@ -5201,8 +5235,8 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
                                sizeof(cache->item));
        BUG_ON(ret);
 
-       finish_current_insert(trans, extent_root);
-       ret = del_pending_extents(trans, extent_root);
+       finish_current_insert(trans, extent_root, 0);
+       ret = del_pending_extents(trans, extent_root, 0);
        BUG_ON(ret);
        set_avail_alloc_bits(extent_root->fs_info, type);
 
@@ -5217,7 +5251,6 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
        struct btrfs_key key;
        int ret;
 
-       BUG_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
        root = root->fs_info->extent_root;
 
        block_group = btrfs_lookup_block_group(root->fs_info, group_start);
@@ -5231,9 +5264,9 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
        btrfs_remove_free_space_cache(block_group);
        rb_erase(&block_group->cache_node,
                 &root->fs_info->block_group_cache_tree);
-       spin_lock(&block_group->space_info->lock);
+       down_write(&block_group->space_info->groups_sem);
        list_del(&block_group->list);
-       spin_unlock(&block_group->space_info->lock);
+       up_write(&block_group->space_info->groups_sem);
 
        /*
        memset(shrink_block_group, 0, sizeof(*shrink_block_group));