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Pass consistent param->type to fs_parse()

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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.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2019-12-17 14:15:04 -05:00
parent 7dc2993a9e
commit 0f89589a8c
4 changed files with 16 additions and 20 deletions
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23
fs/fs_parser.c
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@@ -85,7 +85,6 @@ int fs_parse(struct fs_context *fc,
const struct fs_parameter_enum *e;
int ret = -ENOPARAM, b;
result->has_value = !!param->string;
result->negated = false;
result->uint_64 = 0;
@@ -95,7 +94,7 @@ 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 +126,18 @@ 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 +147,7 @@ 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;
@@ -206,9 +208,6 @@ int fs_parse(struct fs_context *fc,
case fs_param_is_fd: {
switch (param->type) {
case fs_value_is_string:
if (!result->has_value)
goto bad_value;
ret = kstrtouint(param->string, 0, &result->uint_32);
break;
case fs_value_is_file: