While investigating an ext4/053 fstest failure, I realised that when the flag 'fs_param_can_be_empty' is set in a parameter and it's value is NULL that parameter isn't being handled as a 'flag' type. Even if it's type is set to 'fs_value_is_flag'. The first patch in this series changes this behaviour. Unfortunately, the two filesystems that use this flag (ext4 and overlayfs) aren't prepared to have the parameter value set to NULL. Patches #2 and #3 fix this. Luis Henriques (3): fs_parser: handle parameters that can be empty and don't have a value ext4: fix mount parameters check for empty values overlay: fix mount parameters check for empty values fs/ext4/super.c | 4 ++-- fs/fs_parser.c | 3 ++- fs/overlayfs/params.c | 2 +- 3 files changed, 5 insertions(+), 4 deletions(-)