1 files changed, 7 insertions, 4 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 99a8e57da8a1..acf3ed11cfb6 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -10279,22 +10279,25 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
                 block_group = list_first_entry(&fs_info->unused_bgs,
                                                struct btrfs_block_group_cache,
                                                bg_list);
-                space_info = block_group->space_info;
                 list_del_init(&block_group->bg_list);
+
+                space_info = block_group->space_info;
+
                 if (ret || btrfs_mixed_space_info(space_info)) {
                         btrfs_put_block_group(block_group);
                         continue;
                 }
                 spin_unlock(&fs_info->unused_bgs_lock);
 
-                mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
+                mutex_lock(&fs_info->delete_unused_bgs_mutex);
 
                 /* Don't want to race with allocators so take the groups_sem */
                 down_write(&space_info->groups_sem);
                 spin_lock(&block_group->lock);
                 if (block_group->reserved ||
                     btrfs_block_group_used(&block_group->item) ||
-                    block_group->ro) {
+                    block_group->ro ||
+                    list_is_singular(&block_group->list)) {
                         /*
                          * We want to bail if we made new allocations or have
                          * outstanding allocations in this block group.  We do
@@ -10410,7 +10413,7 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
 end_trans:
                 btrfs_end_transaction(trans, root);
 next:
-                mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
+                mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                 btrfs_put_block_group(block_group);
                 spin_lock(&fs_info->unused_bgs_lock);
         }