NFSv4: The NFSv4.0 client must send RENEW calls if it holds a delegation

RFC3530 states that if the client holds a delegation, then it is obliged
to continue to send RENEW calls once every lease period in order to allow
the server to return NFS4ERR_CB_PATH_DOWN if the callback path is
unreachable.

This is not required for NFSv4.1, since the server can at any time set
the SEQ4_STATUS_CB_PATH_DOWN_SESSION in any SEQUENCE operation.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 19 insertions, 6 deletions

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 58adfb6e3657..e1b660728675 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -56,6 +56,9 @@ enum nfs4_session_state {
         NFS4_SESSION_DRAINING,
 };
 
+#define NFS4_RENEW_TIMEOUT              0x01
+#define NFS4_RENEW_DELEGATION_CB        0x02
+
 struct nfs4_minor_version_ops {
         u32     minor_version;
 
@@ -225,7 +228,7 @@ struct nfs4_state_recovery_ops {
 };
 
 struct nfs4_state_maintenance_ops {
-        int (*sched_state_renewal)(struct nfs_client *, struct rpc_cred *);
+        int (*sched_state_renewal)(struct nfs_client *, struct rpc_cred *, unsigned);
         struct rpc_cred * (*get_state_renewal_cred_locked)(struct nfs_client *);
         int (*renew_lease)(struct nfs_client *, struct rpc_cred *);
 };
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index b358ec1d1711..e89940a2819d 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3386,7 +3386,7 @@ static const struct rpc_call_ops nfs4_renew_ops = {
         .rpc_release = nfs4_renew_release,
 };
 
-static int nfs4_proc_async_renew(struct nfs_client *clp, struct rpc_cred *cred)
+static int nfs4_proc_async_renew(struct nfs_client *clp, struct rpc_cred *cred, unsigned renew_flags)
 {
         struct rpc_message msg = {
                 .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_RENEW],
@@ -3395,6 +3395,8 @@ static int nfs4_proc_async_renew(struct nfs_client *clp, struct rpc_cred *cred)
         };
         struct nfs4_renewdata *data;
 
+        if (renew_flags == 0)
+                return 0;
         if (!atomic_inc_not_zero(&clp->cl_count))
                 return -EIO;
         data = kmalloc(sizeof(*data), GFP_NOFS);
@@ -5504,11 +5506,13 @@ static struct rpc_task *_nfs41_proc_sequence(struct nfs_client *clp, struct rpc_
         return rpc_run_task(&task_setup_data);
 }
 
-static int nfs41_proc_async_sequence(struct nfs_client *clp, struct rpc_cred *cred)
+static int nfs41_proc_async_sequence(struct nfs_client *clp, struct rpc_cred *cred, unsigned renew_flags)
 {
         struct rpc_task *task;
         int ret = 0;
 
+        if ((renew_flags & NFS4_RENEW_TIMEOUT) == 0)
+                return 0;
         task = _nfs41_proc_sequence(clp, cred);
         if (IS_ERR(task))
                 ret = PTR_ERR(task);
diff --git a/fs/nfs/nfs4renewd.c b/fs/nfs/nfs4renewd.c
index df8e7f3ca56d..dc484c0eae7f 100644
--- a/fs/nfs/nfs4renewd.c
+++ b/fs/nfs/nfs4renewd.c
@@ -60,6 +60,7 @@ nfs4_renew_state(struct work_struct *work)
         struct rpc_cred *cred;
         long lease;
         unsigned long last, now;
+        unsigned renew_flags = 0;
 
         ops = clp->cl_mvops->state_renewal_ops;
         dprintk("%s: start\n", __func__);
@@ -72,18 +73,23 @@ nfs4_renew_state(struct work_struct *work)
         last = clp->cl_last_renewal;
         now = jiffies;
         /* Are we close to a lease timeout? */
-        if (time_after(now, last + lease/3)) {
+        if (time_after(now, last + lease/3))
+                renew_flags |= NFS4_RENEW_TIMEOUT;
+        if (nfs_delegations_present(clp))
+                renew_flags |= NFS4_RENEW_DELEGATION_CB;
+
+        if (renew_flags != 0) {
                 cred = ops->get_state_renewal_cred_locked(clp);
                 spin_unlock(&clp->cl_lock);
                 if (cred == NULL) {
-                        if (!nfs_delegations_present(clp)) {
+                        if (!(renew_flags & NFS4_RENEW_DELEGATION_CB)) {
                                 set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
                                 goto out;
                         }
                         nfs_expire_all_delegations(clp);
                 } else {
                         /* Queue an asynchronous RENEW. */
-                        ops->sched_state_renewal(clp, cred);
+                        ops->sched_state_renewal(clp, cred, renew_flags);
                         put_rpccred(cred);
                         goto out_exp;
                 }