bcachefs: intercept mountoption value for bool type

For mount option with bool type, the value must be 0 or 1 (See
bch2_opt_parse). But this seems does not well intercepted cause
for other value(like 2...), it returns the unexpect return code
with error message printed.
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/errcode.h

@@ -8,6 +8,7 @@
 	x(EINVAL,			mount_option)				\
 	x(BCH_ERR_mount_option,		option_name)				\
 	x(BCH_ERR_mount_option,		option_value)				\
+	x(BCH_ERR_mount_option,         option_not_bool)                        \
 	x(ENOMEM,			ENOMEM_stripe_buf)			\
 	x(ENOMEM,			ENOMEM_replicas_table)			\
 	x(ENOMEM,			ENOMEM_cpu_replicas)			\

fs/bcachefs/opts.c

@@ -314,7 +314,7 @@ int bch2_opt_parse(struct bch_fs *c,
 		if (ret < 0 || (*res != 0 && *res != 1)) {
 			if (err)
 				prt_printf(err, "%s: must be bool", opt->attr.name);
-			return ret;
+			return ret < 0 ? ret : -BCH_ERR_option_not_bool;
 		}
 		break;
 	case BCH_OPT_UINT: