On Mon, Nov 06, 2017 at 04:25:19PM -0500, Andrew W Elble wrote:
>
> "bfields@xxxxxxxxxxxx" <bfields@xxxxxxxxxxxx> writes:
>
> > I'm just looking for a concise explanation of why your patch is
> > important. And I probably haven't dug enough, but I'm still not quite
> > following.
> >
> > If I understand right, the only visible change from your patch will be
> > returning DELEG_REVOKED instead of BAD_STATEID to 4.1 clients in some
> > cases. I'm not clear what the result was (for old or new clients)--a
> > client left believing it held a delegation when it didn't, or a client
> > entering an infinite state manager loop?
>
> The current Linux client will "lose" a delegation on DELEGRETURN if it
> does not see NFS4ERR_DELEG_REVOKED. This is unrecoverable and will
> result in the client state manager looping unable to satisfy the
> server's inevitable assertion of SEQ4_STATUS_RECALLABLE_STATE_REVOKED.
>
> RFC5661 10.2.1: "A client normally finds out about revocation of a delegation
> when it uses a stateid associated with a delegation and receives one of
> the errors NFS4ERR_EXPIRED, NFS4ERR_ADMIN_REVOKED, or NFS4ERR_DELEG_REVOKED."
Got it, thanks for your persistence! Committing as follows.
--b.
commit 4e9fd30e4432
Author: Andrew Elble <aweits@xxxxxxx>
Date: Fri Nov 3 14:06:31 2017 -0400
nfsd: deal with revoked delegations appropriately
If a delegation has been revoked by the server, operations using that
delegation should error out with NFS4ERR_DELEG_REVOKED in the >4.1
case, and NFS4ERR_BAD_STATEID otherwise.
The server needs NFSv4.1 clients to explicitly free revoked delegations.
If the server returns NFS4ERR_DELEG_REVOKED, the client will do that;
otherwise it may just forget about the delegation and be unable to
recover when it later sees SEQ4_STATUS_RECALLABLE_STATE_REVOKED set on a
SEQUENCE reply. That can cause the Linux 4.1 client to loop in its
stage manager.
Signed-off-by: Andrew Elble <aweits@xxxxxxx>
Reviewed-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index ecbc7b0dfa4d..b82817767b9d 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4016,7 +4016,8 @@ static struct nfs4_delegation *find_deleg_stateid(struct nfs4_client *cl, statei
{
struct nfs4_stid *ret;
- ret = find_stateid_by_type(cl, s, NFS4_DELEG_STID);
+ ret = find_stateid_by_type(cl, s,
+ NFS4_DELEG_STID|NFS4_REVOKED_DELEG_STID);
if (!ret)
return NULL;
return delegstateid(ret);
@@ -4039,6 +4040,12 @@ nfs4_check_deleg(struct nfs4_client *cl, struct nfsd4_open *open,
deleg = find_deleg_stateid(cl, &open->op_delegate_stateid);
if (deleg == NULL)
goto out;
+ if (deleg->dl_stid.sc_type == NFS4_REVOKED_DELEG_STID) {
+ nfs4_put_stid(&deleg->dl_stid);
+ if (cl->cl_minorversion)
+ status = nfserr_deleg_revoked;
+ goto out;
+ }
flags = share_access_to_flags(open->op_share_access);
status = nfs4_check_delegmode(deleg, flags);
if (status) {
@@ -4908,6 +4915,16 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
struct nfs4_stid **s, struct nfsd_net *nn)
{
__be32 status;
+ bool return_revoked = false;
+
+ /*
+ * only return revoked delegations if explicitly asked.
+ * otherwise we report revoked or bad_stateid status.
+ */
+ if (typemask & NFS4_REVOKED_DELEG_STID)
+ return_revoked = true;
+ else if (typemask & NFS4_DELEG_STID)
+ typemask |= NFS4_REVOKED_DELEG_STID;
if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
return nfserr_bad_stateid;
@@ -4922,6 +4939,12 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
*s = find_stateid_by_type(cstate->clp, stateid, typemask);
if (!*s)
return nfserr_bad_stateid;
+ if (((*s)->sc_type == NFS4_REVOKED_DELEG_STID) && !return_revoked) {
+ nfs4_put_stid(*s);
+ if (cstate->minorversion)
+ return nfserr_deleg_revoked;
+ return nfserr_bad_stateid;
+ }
return nfs_ok;
}
--
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