btrfs: clear free space tree creation state on rebuild failure

btrfs_rebuild_free_space_tree() sets BTRFS_FS_CREATING_FREE_SPACE_TREE
before rebuilding the free space tree.  Several error paths return
without clearing this flag.

The transaction restart failure path can leave the flag set on a live
filesystem, causing delayed reference processing to be skipped. Clear it
on all free space tree rebuild failure paths. Keep
BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED set, since a failed rebuild leaves
the free space tree untrusted. Callers must fall back to extent-tree
caching.

Fixes: 882af9f13e83 ("btrfs: handle free space tree rebuild in multiple transactions")
CC: stable@vger.kernel.org # 6.14+
Assisted-by: LLM
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Guanghui Yang <3497809730@qq.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c
index 1b3d82ae3de80ee114c19e56191052084374d78b..b7a4a6ade30f0efdecdaf322d5d7f2b34af1bf47 100644 (file)
--- a/fs/btrfs/free-space-tree.c
+++ b/fs/btrfs/free-space-tree.c
@@ -1353,7 +1353,7 @@ int btrfs_rebuild_free_space_tree(struct btrfs_fs_info *fs_info)
        if (unlikely(ret)) {
                btrfs_abort_transaction(trans, ret);
                btrfs_end_transaction(trans);
-               return ret;
+               goto out_clear;
        }
 
        node = rb_first_cached(&fs_info->block_group_cache_tree);
@@ -1371,14 +1371,16 @@ int btrfs_rebuild_free_space_tree(struct btrfs_fs_info *fs_info)
                if (unlikely(ret)) {
                        btrfs_abort_transaction(trans, ret);
                        btrfs_end_transaction(trans);
-                       return ret;
+                       goto out_clear;
                }
 next:
                if (btrfs_should_end_transaction(trans)) {
                        btrfs_end_transaction(trans);
                        trans = btrfs_start_transaction(free_space_root, 1);
-                       if (IS_ERR(trans))
-                               return PTR_ERR(trans);
+                       if (IS_ERR(trans)) {
+                               ret = PTR_ERR(trans);
+                               goto out_clear;
+                       }
                }
                node = rb_next(node);
        }
@@ -1390,6 +1392,10 @@ next:
        ret = btrfs_commit_transaction(trans);
        clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
        return ret;
+
+out_clear:
+       clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
+       return ret;
 }
 
 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,