btrfs: error on missing block group when unaccounting log tree extent buffers

Currently we only log an error message if we can't find the block group
for a log tree extent buffer when unaccounting it (while freeing a log
tree). A missing block group means something is seriously wrong and we
end up leaking space from the metadata space info. So return -ENOENT in
case we don't find the block group.

CC: stable@vger.kernel.org # 6.12+
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 2186e87fb61b094346d731420b94706c213c27e0..69e11557fd13d80c5be7dafe3376a98d1301aa1b 100644 (file)
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2605,14 +2605,14 @@ static int replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb,
 /*
  * Correctly adjust the reserved bytes occupied by a log tree extent buffer
  */
-static void unaccount_log_buffer(struct btrfs_fs_info *fs_info, u64 start)
+static int unaccount_log_buffer(struct btrfs_fs_info *fs_info, u64 start)
 {
        struct btrfs_block_group *cache;
 
        cache = btrfs_lookup_block_group(fs_info, start);
        if (!cache) {
                btrfs_err(fs_info, "unable to find block group for %llu", start);
-               return;
+               return -ENOENT;
        }
 
        spin_lock(&cache->space_info->lock);
@@ -2623,27 +2623,22 @@ static void unaccount_log_buffer(struct btrfs_fs_info *fs_info, u64 start)
        spin_unlock(&cache->space_info->lock);
 
        btrfs_put_block_group(cache);
+
+       return 0;
 }
 
 static int clean_log_buffer(struct btrfs_trans_handle *trans,
                            struct extent_buffer *eb)
 {
-       int ret;
-
        btrfs_tree_lock(eb);
        btrfs_clear_buffer_dirty(trans, eb);
        wait_on_extent_buffer_writeback(eb);
        btrfs_tree_unlock(eb);
 
-       if (trans) {
-               ret = btrfs_pin_reserved_extent(trans, eb);
-               if (ret)
-                       return ret;
-       } else {
-               unaccount_log_buffer(eb->fs_info, eb->start);
-       }
+       if (trans)
+               return btrfs_pin_reserved_extent(trans, eb);
 
-       return 0;
+       return unaccount_log_buffer(eb->fs_info, eb->start);
 }
 
 static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,