String options always have parameters, hence the check for optional parameter will never trigger. Check for param type being a flag first (flag is the only type that does not have a parameter) and report "Missing value" if the parameter is mandatory. Tested with gfs2's "quota" option, which is currently the only user of fs_param_v_optional. Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx> Cc: Andrew Price <anprice@xxxxxxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Fixes: 31d921c7fb96 ("vfs: Add configuration parser helpers") Cc: <stable@xxxxxxxxxxxxxxx> # v5.4 --- fs/fs_parser.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/fs_parser.c b/fs/fs_parser.c index d1930adce68d..5d8833d71b37 100644 --- a/fs/fs_parser.c +++ b/fs/fs_parser.c @@ -127,13 +127,15 @@ int fs_parse(struct fs_context *fc, case fs_param_is_u64: case fs_param_is_enum: case fs_param_is_string: - if (param->type != fs_value_is_string) - goto bad_value; - if (!result->has_value) { + if (param->type == fs_value_is_flag) { if (p->flags & fs_param_v_optional) goto okay; - goto bad_value; + + return invalf(fc, "%s: Missing value for '%s'", + desc->name, param->key); } + if (param->type != fs_value_is_string) + goto bad_value; /* Fall through */ default: break; -- 2.21.0