diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index c86fb5438454..6f49b2872a64 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1000,6 +1000,16 @@ int btrfs_sync_fs(struct super_block *sb, int wait) */ if (fs_info->pending_changes == 0) return 0; + /* + * A non-blocking test if the fs is frozen. We must not + * start a new transaction here otherwise a deadlock + * happens. The pending operations are delayed to the + * next commit after thawing. + */ + if (__sb_start_write(sb, SB_FREEZE_WRITE, false)) + __sb_end_write(sb, SB_FREEZE_WRITE); + else + return 0; trans = btrfs_start_transaction(root, 0); } if (IS_ERR(trans))