NFSv4.1 fix infinite loop on I/O.

The previous fix broke recovery of delegated stateids because it assumes
that if we did not mark the delegation as suspect, then the delegation has
effectively been revoked, and so it removes that delegation irrespectively
of whether or not it is valid and still in use. While this is "mostly
harmless" for ordinary I/O, we've seen pNFS fail with LAYOUTGET spinning
in an infinite loop while complaining that we're using an invalid stateid
(in this case the all-zero stateid).

What we rather want to do here is ensure that the delegation is always
correctly marked as needing testing when that is the case. So we want
to close the loophole offered by nfs4_schedule_stateid_recovery(),
which marks the state as needing to be reclaimed, but not the
delegation that may be backing it.

Fixes: 161f99c48dbaa ("NFSv4.1 fix infinite loop on IO BAD_STATEID error")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index df60dce935f36231c4993dda2ccfec3e282770a0..094c3c09ff004accc8a8b9a15c09f389489a2eff 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2676,14 +2676,18 @@ static void nfs41_check_delegation_stateid(struct nfs4_state *state)
        }
 
        nfs4_stateid_copy(&stateid, &delegation->stateid);
-       if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) ||
-               !test_and_clear_bit(NFS_DELEGATION_TEST_EXPIRED,
-                       &delegation->flags)) {
+       if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
                rcu_read_unlock();
                nfs_finish_clear_delegation_stateid(state, &stateid);
                return;
        }
 
+       if (!test_and_clear_bit(NFS_DELEGATION_TEST_EXPIRED,
+                               &delegation->flags)) {
+               rcu_read_unlock();
+               return;
+       }
+
        cred = get_rpccred(delegation->cred);
        rcu_read_unlock();
        status = nfs41_test_and_free_expired_stateid(server, &stateid, cred);

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 3df0eb52da1c97d3802c34702068a36f31f02d69..40a08cd483f051072508b53eee362167ce26904f 100644 (file)
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1390,6 +1390,8 @@ int nfs4_schedule_stateid_recovery(const struct nfs_server *server, struct nfs4_
 
        if (!nfs4_state_mark_reclaim_nograce(clp, state))
                return -EBADF;
+       nfs_inode_find_delegation_state_and_recover(state->inode,
+                       &state->stateid);
        dprintk("%s: scheduling stateid recovery for server %s\n", __func__,
                        clp->cl_hostname);
        nfs4_schedule_state_manager(clp);