2023-02-03 00:57:19

by Chuck Lever III

[permalink] [raw]
Subject: Re: [PATCH] NFSD: fix deny mode logic in nfs4_upgrade_open



> On Feb 2, 2023, at 7:50 PM, 張智諺 <[email protected]> wrote:
>
> Sorry, I thought the set deny mode operation was the error handling of nfserr_inval, and fixed it with the one-liner wrongly. Thanks your explanation.

Do you happen to have a test case for this issue?
Getting a Tested-by: would be great.


> Jeff Layton <[email protected]> 於 2023年2月3日 週五 上午5:22寫道:
> On Thu, 2023-02-02 at 19:41 +0000, Chuck Lever III wrote:
> >
> > > On Feb 2, 2023, at 2:36 AM, Pumpkin <[email protected]> wrote:
> > >
> > > If the upgrading deny mode is invalid or conflicts with other client, we
> > > should try to resolve it, but the if-condition makes those error handling
> > > cannot be executed.
> > >
> > > Signed-off-by: Pumpkin <[email protected]>
> > > ---
> > > fs/nfsd/nfs4state.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > > index 4ef529379..ebdfaf0f9 100644
> > > --- a/fs/nfsd/nfs4state.c
> > > +++ b/fs/nfsd/nfs4state.c
> > > @@ -5298,7 +5298,7 @@ nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp,
> > > /* test and set deny mode */
> > > spin_lock(&fp->fi_lock);
> > > status = nfs4_file_check_deny(fp, open->op_share_deny);
> > > - if (status == nfs_ok) {
> > > + if (status != nfs_ok) {
> > > if (status != nfserr_share_denied) {
> >
> > if status == nfs_ok then status will definitely not equal
> > share_denied. So this check is a bit nonsensical as it stands.
> >
> > Usually I prefer "switch (status)" in situations like this
> > because that avoids this kind of issue and I find it easier
> > to read quickly.
> >
> > Jeff, you are the original author of this function, and
> > Dai, your commit is the last one to touch this area. Can
> > you guys have a look? The one-liner looks correct, but I
> > might be missing something.
> >
>
> Yeah, that code is clearly broken and it looks like it was done in
> 3d69427151806 (NFSD: add support for share reservation conflict to
> courteous server).
>
> I don't believe that one-liner is correct though. If the result is
> nfs_ok, then we want to set the deny mode here and that won't happen.
>
> Something like this maybe? (completely untested):
>
> ---------------8<-------------------
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index c39e43742dd6..af22dfdc6fcc 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -5282,16 +5282,17 @@ nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp,
> /* test and set deny mode */
> spin_lock(&fp->fi_lock);
> status = nfs4_file_check_deny(fp, open->op_share_deny);
> - if (status == nfs_ok) {
> - if (status != nfserr_share_denied) {
> - set_deny(open->op_share_deny, stp);
> - fp->fi_share_deny |=
> - (open->op_share_deny & NFS4_SHARE_DENY_BOTH);
> - } else {
> - if (nfs4_resolve_deny_conflicts_locked(fp, false,
> - stp, open->op_share_deny, false))
> - status = nfserr_jukebox;
> - }
> + switch (status) {
> + case nfs_ok:
> + set_deny(open->op_share_deny, stp);
> + fp->fi_share_deny |=
> + (open->op_share_deny & NFS4_SHARE_DENY_BOTH);
> + break;
> + case nfserr_share_denied:
> + if (nfs4_resolve_deny_conflicts_locked(fp, false,
> + stp, open->op_share_deny, false))
> + status = nfserr_jukebox;
> + break;
> }
> spin_unlock(&fp->fi_lock);
>
> --
> Jeff Layton <[email protected]>

--
Chuck Lever