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 --- fs/btrfs/super.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 580ba7db67e5..a2554c651548 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1834,6 +1834,8 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) }
if (btrfs_super_log_root(fs_info->super_copy) != 0) { + btrfs_warn(f_info, + "mount required to replay tree-log, cannot remount read-write"); ret = -EINVAL; goto restore; }