A remount to a read-write filesystem is not safe when there's tree-log to be replayed. Files that could be opened until now might be affected by the changes in the tree-log.

A regular mount is needed to replay the log so the filesystem presents the consistent view with the pending changes included.

CC: stable@vger.kernel.org # 4.4+ Signed-off-by: David Sterba dsterba@suse.com ---

* fix typo in fs_info parameter

fs/btrfs/super.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 2bfccc40d0fb..5c16b4bcde9b 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1841,6 +1841,8 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) }

if (btrfs_super_log_root(fs_info->super_copy) != 0) { + btrfs_warn(fs_info, + "mount required to replay tree-log, cannot remount read-write"); ret = -EINVAL; goto restore; }