From: Al Viro <viro@zeniv.linux.org.uk>
Date: Tue, 17 Dec 2019 14:15:04 -0500
Subject: [PATCH] Pass consistent param->type to fs_parse()
Git-commit: 0f89589a8c6f1033cb847a606517998efb0da8ee
References: bsc#1192606
Patch-mainline: v5.6-rc1
As it is, vfs_parse_fs_string() makes "foo" and "foo=" indistinguishable;
both get fs_value_is_string for ->type and NULL for ->string. To make
it even more unpleasant, that combination is impossible to produce with
fsconfig().
Much saner rules would be
"foo" => fs_value_is_flag, NULL
"foo=" => fs_value_is_string, ""
"foo=bar" => fs_value_is_string, "bar"
All cases are distinguishable, all results are expressable by fsconfig(),
->has_value checks are much simpler that way (to the point of the field
being useless) and quite a few regressions go away (gfs2 has no business
accepting -o nodebug=, for example).
Partially based upon patches from Miklos.
[ ematsumiya: drop the case fs_param_is_fd, and leave .has_value in struct
fs_parse_result so it doesn't break kabi ]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
drivers/block/rbd.c | 7 ++-----
fs/fs_context.c | 5 +++--
fs/fs_parser.c | 19 +++++++++++--------
3 files changed, 16 insertions(+), 15 deletions(-)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -6433,7 +6433,7 @@ static int rbd_parse_options(char *optio
if (*key) {
struct fs_parameter param = {
.key = key,
- .type = fs_value_is_string,
+ .type = fs_value_is_flag,
};
char *value = strchr(key, '=');
size_t v_len = 0;
@@ -6443,14 +6443,11 @@ static int rbd_parse_options(char *optio
continue;
*value++ = 0;
v_len = strlen(value);
- }
-
-
- if (v_len > 0) {
param.string = kmemdup_nul(value, v_len,
GFP_KERNEL);
if (!param.string)
return -ENOMEM;
+ param.type = fs_value_is_string;
}
param.size = v_len;
--- a/fs/fs_context.c
+++ b/fs/fs_context.c
@@ -175,14 +175,15 @@ int vfs_parse_fs_string(struct fs_contex
struct fs_parameter param = {
.key = key,
- .type = fs_value_is_string,
+ .type = fs_value_is_flag,
.size = v_size,
};
- if (v_size > 0) {
+ if (value) {
param.string = kmemdup_nul(value, v_size, GFP_KERNEL);
if (!param.string)
return -ENOMEM;
+ param.type = fs_value_is_string;
}
ret = vfs_parse_fs_param(fc, ¶m);
--- a/fs/fs_parser.c
+++ b/fs/fs_parser.c
@@ -95,7 +95,7 @@ int fs_parse(struct fs_context *fc,
* "xxx" takes the "no"-form negative - but only if there
* wasn't an value.
*/
- if (result->has_value)
+ if (param->type != fs_value_is_flag)
goto unknown_parameter;
if (param->key[0] != 'n' || param->key[1] != 'o' || !param->key[2])
goto unknown_parameter;
@@ -127,14 +127,18 @@ 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_string) {
+ if (p->flags & fs_param_v_optional)
+ break;
+ if (!*param->string)
+ goto bad_value;
+ break;
+ }
+ if (param->type == fs_value_is_flag) {
if (p->flags & fs_param_v_optional)
goto okay;
- goto bad_value;
}
- /* Fall through */
+ goto bad_value;
default:
break;
}
@@ -144,8 +148,7 @@ int fs_parse(struct fs_context *fc,
*/
switch (p->type) {
case fs_param_is_flag:
- if (param->type != fs_value_is_flag &&
- (param->type != fs_value_is_string || result->has_value))
+ if (param->type != fs_value_is_flag)
return invalf(fc, "%s: Unexpected value for '%s'",
desc->name, param->key);
result->boolean = true;