Re: git: 2a1d50fc12f6 - main - vfs_domount_update(): correct fsidcmp() usage
Date: Tue, 26 Dec 2023 03:57:54 UTC
On Tue, Dec 26, 2023 at 11:31:38AM +0800, Zhenlei Huang wrote:
>
>
> > On Dec 26, 2023, at 11:29 AM, Zhenlei Huang <zlei@FreeBSD.org> wrote:
> >
> >
> >
> >> On Dec 26, 2023, at 9:36 AM, Konstantin Belousov <kib@FreeBSD.org <mailto:kib@FreeBSD.org>> wrote:
> >>
> >> The branch main has been updated by kib:
> >>
> >> URL: https://cgit.FreeBSD.org/src/commit/?id=2a1d50fc12f6e604da834fbaea961d412aae6e85 <https://cgit.freebsd.org/src/commit/?id=2a1d50fc12f6e604da834fbaea961d412aae6e85>
> >>
> >> commit 2a1d50fc12f6e604da834fbaea961d412aae6e85
> >> Author: Andrew Gierth <andrew@tao146.riddles.org.uk <mailto:andrew@tao146.riddles.org.uk>>
> >> AuthorDate: 2023-12-24 12:04:21 +0000
> >> Commit: Konstantin Belousov <kib@FreeBSD.org <mailto:kib@FreeBSD.org>>
> >> 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;
> >> }
> >
> >
>
> The fsidcmp is currently defined as
> ```
> #define fsidcmp(a, b) memcmp((a), (b), sizeof(fsid_t))
> ```
Yes, and the issue should be fixed by making it (inline) function, which
automatically would type-check it args.
>
> >
> > 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 <https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html>
> > 2. https://clang.llvm.org/docs/LanguageExtensions.html <https://clang.llvm.org/docs/LanguageExtensions.html>
> > Best regards,
> > Zhenlei
> >
>
>