On Wed, Aug 28, 2024 at 03:02:42PM +1000, NeilBrown wrote:
> On Wed, 28 Aug 2024, cel@xxxxxxxxxx wrote:
> > From: Chuck Lever <chuck.lever@xxxxxxxxxx>
> >
> > Currently, fh_verify() makes some daring assumptions about which
> > version of file handle the caller wants, based on the things it can
> > find in the passed-in rqstp. The about-to-be-introduced LOCALIO use
> > case sometimes has no svc_rqst context, so this logic won't work in
> > that case.
> >
> > Instead, examine the passed-in file handle. It's .max_size field
> > should carry information to allow nfsd_set_fh_dentry() to initialize
> > the file handle appropriately.
> >
> > lockd appears to be the only kernel consumer that does not set the
> > file handle .max_size when during initialization.
> >
> > write_filehandle() is the other question mark, as it looks possible
> > to specify a maxsize between NFS_FHSIZE and NFS3_FHSIZE here.
>
> The file handle used by lockd and the one created by write_filehandle
> never need any of the version-specific fields.
> Those fields affect things like write requests and getattr requests and
> pre/post attributes.
Then we could simply drop the "case 0:" arm and maybe the lockd hunk
from this patch.
> I wonder if the filehandle is really the best place of these flag.
> Having them in the file handle works really well for fh_fill_pre_attrs()
> and reasonably well in other places, But it makes nfsd_set_fh_dentry a
> little clumsy.
The file handle initialization code in here is indeed a bit awkward.
I didn't take it further in this patch set because I didn't have any
brilliant ideas, other than perhaps a version-specific
initialization call-out.
I don't think we need to go there to implement LOCALIO, but we could
save such a clean-up for another day.
> Maybe it would be better to moved them to
> rqstp->rq_flags. Or possibly in the "Catering to nfsd" section of
> 'struct svc_rqst'.
Jeff and I have agreed to migrate NFS (or any upper layer protocol)
specifics out of the svc_rqst, where possible, simply to maintain
proper layering. I don't have any better ideas, though.
> NeilBrown
>
>
> >
> > Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> > ---
> > fs/nfsd/lockd.c | 6 ++++--
> > fs/nfsd/nfsfh.c | 11 +++++++----
> > 2 files changed, 11 insertions(+), 6 deletions(-)
> >
> > diff --git a/fs/nfsd/lockd.c b/fs/nfsd/lockd.c
> > index 46a7f9b813e5..e636d2a1e664 100644
> > --- a/fs/nfsd/lockd.c
> > +++ b/fs/nfsd/lockd.c
> > @@ -32,8 +32,10 @@ nlm_fopen(struct svc_rqst *rqstp, struct nfs_fh *f, struct file **filp,
> > int access;
> > struct svc_fh fh;
> >
> > - /* must initialize before using! but maxsize doesn't matter */
> > - fh_init(&fh,0);
> > + if (rqstp->rq_vers == 4)
> > + fh_init(&fh, NFS3_FHSIZE);
> > + else
> > + fh_init(&fh, NFS_FHSIZE);
> > fh.fh_handle.fh_size = f->size;
> > memcpy(&fh.fh_handle.fh_raw, f->data, f->size);
> > fh.fh_export = NULL;
> > diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
> > index 4b964a71a504..77acc26e8b02 100644
> > --- a/fs/nfsd/nfsfh.c
> > +++ b/fs/nfsd/nfsfh.c
> > @@ -267,25 +267,28 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
> > fhp->fh_dentry = dentry;
> > fhp->fh_export = exp;
> >
> > - switch (rqstp->rq_vers) {
> > - case 4:
> > + switch (fhp->fh_maxsize) {
> > + case NFS4_FHSIZE:
> > if (dentry->d_sb->s_export_op->flags & EXPORT_OP_NOATOMIC_ATTR)
> > fhp->fh_no_atomic_attr = true;
> > fhp->fh_64bit_cookies = true;
> > break;
> > - case 3:
> > + case NFS3_FHSIZE:
> > if (dentry->d_sb->s_export_op->flags & EXPORT_OP_NOWCC)
> > fhp->fh_no_wcc = true;
> > fhp->fh_64bit_cookies = true;
> > if (exp->ex_flags & NFSEXP_V4ROOT)
> > goto out;
> > break;
> > - case 2:
> > + case NFS_FHSIZE:
> > fhp->fh_no_wcc = true;
> > if (EX_WGATHER(exp))
> > fhp->fh_use_wgather = true;
> > if (exp->ex_flags & NFSEXP_V4ROOT)
> > goto out;
> > + break;
> > + case 0:
> > + WARN_ONCE(1, "Uninitialized file handle");
> > }
> >
> > return 0;
> > --
> > 2.45.2
> >
> >
>
--
Chuck Lever
