Re: git: a1d71cebc05c - main - fstatat(2): restore AT_EMPTY_PATH handling

right, this should do it

diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c
index e4977392349f..b583eed5e249 100644
--- a/sys/kern/vfs_cache.c
+++ b/sys/kern/vfs_cache.c
@@ -4435,6 +4435,7 @@ cache_fplookup_dirfd(struct cache_fpl *fpl,
struct vnode **vpp)
        if ((*vpp)->v_type != VDIR) {
                if (!((cnp->cn_flags & EMPTYPATH) != 0 &&
cnp->cn_pnbuf[0] == '\0')) {
                        cache_fpl_smr_exit(fpl);
+                       ndp->ni_resflags |= NIRES_EMPTYPATH;
                        return (cache_fpl_handled_error(fpl, ENOTDIR));
                }
        }


On 5/2/23, Dmitry Chagin <dchagin@freebsd.org> wrote:
> On Tue, May 02, 2023 at 03:04:37PM -0400, Mark Johnston wrote:
>> On Tue, May 02, 2023 at 08:00:01PM +0300, Dmitry Chagin wrote:
>> > On Tue, May 02, 2023 at 03:12:51PM +0000, Konstantin Belousov wrote:
>> > > The branch main has been updated by kib:
>> > >
>> > > URL:
>> > > https://cgit.FreeBSD.org/src/commit/?id=a1d71cebc05ccfeedf95f2db3e94b17270167888
>> > >
>> > > commit a1d71cebc05ccfeedf95f2db3e94b17270167888
>> > > Author:     Konstantin Belousov <kib@FreeBSD.org>
>> > > AuthorDate: 2023-05-02 15:11:39 +0000
>> > > Commit:     Konstantin Belousov <kib@FreeBSD.org>
>> > > CommitDate: 2023-05-02 15:11:39 +0000
>> > >
>> > >     fstatat(2): restore AT_EMPTY_PATH handling
>> > >
>> > >     Fixes:  cb858340dcbf214cc4c4d78dbb741620d7b3a252
>> > >     Reported by:    markj
>> > >     Sponsored by:   The FreeBSD Foundation
>> > > ---
>> > >  sys/kern/vfs_syscalls.c | 6 +++++-
>> > >  1 file changed, 5 insertions(+), 1 deletion(-)
>> > >
>> > > diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
>> > > index 5c0a291e3b0b..d68af4ea4d51 100644
>> > > --- a/sys/kern/vfs_syscalls.c
>> > > +++ b/sys/kern/vfs_syscalls.c
>> > > @@ -2438,8 +2438,12 @@ kern_statat(struct thread *td, int flag, int
>> > > fd, const char *path,
>> > >  	    AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH) | LOCKSHARED | LOCKLEAF |
>> > >  	    AUDITVNODE1, pathseg, path, fd, &cap_fstat_rights);
>> > >
>> > > -	if ((error = namei(&nd)) != 0)
>> > > +	if ((error = namei(&nd)) != 0) {
>> > > +		if (error == ENOTDIR &&
>> > > +		    (nd.ni_resflags & NIRES_EMPTYPATH) != 0)
>> > > +			error = kern_fstat(td, fd, sbp);
>> > >  		return (error);
>> > > +	}
>> >
>> > cache_fplookup_dirfd() doesnt set the NIRES_EMPTYPATH flag
>>
>> It doesn't, but for an AT_EMPTY_PATH lookup it aborts the lookup and
>> returns ENOTDIR to namei(), which sets NIRES_EMPTYPATH before passing
>> the error up.
>>
>
> it call cache_fpl_handled_error() which is set status to
> CACHE_FPL_STATUS_HADLED, namei() simply return error in that path
>
>
>> > >  	error = VOP_STAT(nd.ni_vp, sbp, td->td_ucred, NOCRED);
>> > >  	NDFREE_PNBUF(&nd);
>> > >  	vput(nd.ni_vp);
>> >
>


-- 
Mateusz Guzik <mjguzik gmail.com>