[PATCH 4.4 27/96] nfsd: deal with revoked delegations appropriately

Greg Kroah-Hartman
2017-11-28T10:29:14Z

From: Andrew Elble <aweits@rit.edu>

commit 95da1b3a5aded124dd1bda1e3cdb876184813140 upstream.

If a delegation has been revoked by the server, operations using that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@rit.edu>
Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfsd/nfs4state.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)

--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3829,7 +3829,8 @@ static struct nfs4_delegation *find_dele
{
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);
@@ -3852,6 +3853,12 @@ nfs4_check_deleg(struct nfs4_client *cl,
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) {
@@ -4696,6 +4703,16 @@ nfsd4_lookup_stateid(struct nfsd4_compou
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;
@@ -4710,6 +4727,12 @@ nfsd4_lookup_stateid(struct nfsd4_compou
*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;
}