> 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.
Both ext4 and overlayfs define
#define fsparam_string_empty(NAME, OPT) \
__fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL)
Please add that to include/linux/fs_parser.h so that it can be used by both.
