> On Dec 26, 2023, at 9:36 AM, Konstantin Belousov <[email protected]> wrote:
>
> The branch main has been updated by kib:
>
> URL:
> https://cgit.FreeBSD.org/src/commit/?id=2a1d50fc12f6e604da834fbaea961d412aae6e85
>
> commit 2a1d50fc12f6e604da834fbaea961d412aae6e85
> Author: Andrew Gierth <[email protected]>
> AuthorDate: 2023-12-24 12:04:21 +0000
> Commit: Konstantin Belousov <[email protected]>
> CommitDate: 2023-12-26 01:35:46 +0000
>
> vfs_domount_update(): correct fsidcmp() usage
>
> MFC after: 3 days
> ---
> sys/kern/vfs_mount.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
> index 8e54c832e9f1..331e4887c200 100644
> --- a/sys/kern/vfs_mount.c
> +++ b/sys/kern/vfs_mount.c
> @@ -1388,7 +1388,7 @@ vfs_domount_update(
> error = EINVAL;
> goto end;
> }
> - if (fsidcmp(&fsid_up, &mp->mnt_stat.f_fsid) != 0) {
> + if (fsidcmp(fsid_up, &mp->mnt_stat.f_fsid) != 0) {
> error = ENOENT;
> goto end;
> }
I guess we want to ensure ` typeof(a) == typeof(b) == fsid_t `, to prevent such
kind of error in future.
I see both gcc [1] and clang [2] have __builtin_types_compatible_p , so
probably a good definition of fsidcmp should be
```
#define TYPEASSERT(v, t) \
_Static_assert(__builtin_types_compatible_p(typeof(v), t), "Requires
type '" #t "'")
#define fsidcmp(a, b) ({ \
TYPEASSERT((a), fsid_t *); \
TYPEASSERT((b), fsid_t *); \
memcmp((a), (b), sizeof(fsid_t)); \
})
```
1. https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html
2. https://clang.llvm.org/docs/LanguageExtensions.html
Best regards,
Zhenlei
