1 files changed, 41 insertions, 29 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a5aca3997d42..62a332d34fdb 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2387,13 +2387,29 @@ fail:
 
 }
 
+static struct btrfs_block_group_cache *
+next_block_group(struct btrfs_root *root,
+                 struct btrfs_block_group_cache *cache)
+{
+        struct rb_node *node;
+        spin_lock(&root->fs_info->block_group_cache_lock);
+        node = rb_next(&cache->cache_node);
+        btrfs_put_block_group(cache);
+        if (node) {
+                cache = rb_entry(node, struct btrfs_block_group_cache,
+                                 cache_node);
+                atomic_inc(&cache->count);
+        } else
+                cache = NULL;
+        spin_unlock(&root->fs_info->block_group_cache_lock);
+        return cache;
+}
+
 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
                                    struct btrfs_root *root)
 {
-        struct btrfs_block_group_cache *cache, *entry;
-        struct rb_node *n;
+        struct btrfs_block_group_cache *cache;
         int err = 0;
-        int werr = 0;
         struct btrfs_path *path;
         u64 last = 0;
 
@@ -2402,39 +2418,35 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
                 return -ENOMEM;
 
         while (1) {
-                cache = NULL;
-                spin_lock(&root->fs_info->block_group_cache_lock);
-                for (n = rb_first(&root->fs_info->block_group_cache_tree);
-                     n; n = rb_next(n)) {
-                        entry = rb_entry(n, struct btrfs_block_group_cache,
-                                         cache_node);
-                        if (entry->dirty) {
-                                cache = entry;
-                                break;
-                        }
+                if (last == 0) {
+                        err = btrfs_run_delayed_refs(trans, root,
+                                                     (unsigned long)-1);
+                        BUG_ON(err);
                 }
-                spin_unlock(&root->fs_info->block_group_cache_lock);
 
-                if (!cache)
-                        break;
+                cache = btrfs_lookup_first_block_group(root->fs_info, last);
+                while (cache) {
+                        if (cache->dirty)
+                                break;
+                        cache = next_block_group(root, cache);
+                }
+                if (!cache) {
+                        if (last == 0)
+                                break;
+                        last = 0;
+                        continue;
+                }
 
                 cache->dirty = 0;
-                last += cache->key.offset;
+                last = cache->key.objectid + cache->key.offset;
 
-                err = write_one_cache_group(trans, root,
-                                            path, cache);
-                /*
-                 * if we fail to write the cache group, we want
-                 * to keep it marked dirty in hopes that a later
-                 * write will work
-                 */
-                if (err) {
-                        werr = err;
-                        continue;
-                }
+                err = write_one_cache_group(trans, root, path, cache);
+                BUG_ON(err);
+                btrfs_put_block_group(cache);
         }
+
         btrfs_free_path(path);
-        return werr;
+        return 0;
 }
 
 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)