nfs41: RECLAIM_COMPLETE functionality

Implements RECLAIM_COMPLETE as an asynchronous RPC.
NFS4ERR_DELAY is retried, NFS4ERR_DEADSESSION invokes the error handling
but does not result in a retry, since we don't want to have a lingering
RECLAIM_COMPLETE call sent in the middle of a possible new state recovery
cycle.  If a session reset occurs, a new wave of reclaim operations will
follow, containing their own RECLAIM_COMPLETE call.  We don't want a
retry to get on the way of recovery by incorrectly indicating to the
server that we're done reclaiming state.

A subsequent patch invokes the functionality.

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

3 files changed, 114 insertions, 0 deletions

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 9a866368896a..90923223a7c1 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -181,6 +181,7 @@ struct nfs4_state_recovery_ops {
         int (*recover_lock)(struct nfs4_state *, struct file_lock *);
         int (*establish_clid)(struct nfs_client *, struct rpc_cred *);
         struct rpc_cred * (*get_clid_cred)(struct nfs_client *);
+        int (*reclaim_complete)(struct nfs_client *);
 };
 
 struct nfs4_state_maintenance_ops {
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 71993f122214..206ce30a595d 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4971,6 +4971,110 @@ static int nfs41_proc_async_sequence(struct nfs_client *clp,
                               &nfs41_sequence_ops, (void *)clp);
 }
 
+struct nfs4_reclaim_complete_data {
+        struct nfs_client *clp;
+        struct nfs41_reclaim_complete_args arg;
+        struct nfs41_reclaim_complete_res res;
+};
+
+static void nfs4_reclaim_complete_prepare(struct rpc_task *task, void *data)
+{
+        struct nfs4_reclaim_complete_data *calldata = data;
+
+        if (nfs4_setup_sequence(calldata->clp, &calldata->arg.seq_args,
+                                &calldata->res.seq_res, 0, task))
+                return;
+
+        rpc_call_start(task);
+}
+
+static void nfs4_reclaim_complete_done(struct rpc_task *task, void *data)
+{
+        struct nfs4_reclaim_complete_data *calldata = data;
+        struct nfs_client *clp = calldata->clp;
+        struct nfs4_sequence_res *res = &calldata->res.seq_res;
+
+        dprintk("--> %s\n", __func__);
+        nfs41_sequence_done(clp, res, task->tk_status);
+        switch (task->tk_status) {
+        case 0:
+        case -NFS4ERR_COMPLETE_ALREADY:
+                break;
+        case -NFS4ERR_BADSESSION:
+        case -NFS4ERR_DEADSESSION:
+                /*
+                 * Handle the session error, but do not retry the operation, as
+                 * we have no way of telling whether the clientid had to be
+                 * reset before we got our reply.  If reset, a new wave of
+                 * reclaim operations will follow, containing their own reclaim
+                 * complete.  We don't want our retry to get on the way of
+                 * recovery by incorrectly indicating to the server that we're
+                 * done reclaiming state since the process had to be restarted.
+                 */
+                _nfs4_async_handle_error(task, NULL, clp, NULL);
+                break;
+        default:
+                if (_nfs4_async_handle_error(
+                                task, NULL, clp, NULL) == -EAGAIN) {
+                        rpc_restart_call_prepare(task);
+                        return;
+                }
+        }
+        nfs41_sequence_free_slot(clp, res);
+
+        dprintk("<-- %s\n", __func__);
+}
+
+static void nfs4_free_reclaim_complete_data(void *data)
+{
+        struct nfs4_reclaim_complete_data *calldata = data;
+
+        kfree(calldata);
+}
+
+static const struct rpc_call_ops nfs4_reclaim_complete_call_ops = {
+        .rpc_call_prepare = nfs4_reclaim_complete_prepare,
+        .rpc_call_done = nfs4_reclaim_complete_done,
+        .rpc_release = nfs4_free_reclaim_complete_data,
+};
+
+/*
+ * Issue a global reclaim complete.
+ */
+static int nfs41_proc_reclaim_complete(struct nfs_client *clp)
+{
+        struct nfs4_reclaim_complete_data *calldata;
+        struct rpc_task *task;
+        struct rpc_message msg = {
+                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RECLAIM_COMPLETE],
+        };
+        struct rpc_task_setup task_setup_data = {
+                .rpc_client = clp->cl_rpcclient,
+                .rpc_message = &msg,
+                .callback_ops = &nfs4_reclaim_complete_call_ops,
+                .flags = RPC_TASK_ASYNC,
+        };
+        int status = -ENOMEM;
+
+        dprintk("--> %s\n", __func__);
+        calldata = kzalloc(sizeof(*calldata), GFP_KERNEL);
+        if (calldata == NULL)
+                goto out;
+        calldata->clp = clp;
+        calldata->arg.one_fs = 0;
+        calldata->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
+
+        msg.rpc_argp = &calldata->arg;
+        msg.rpc_resp = &calldata->res;
+        task_setup_data.callback_data = calldata;
+        task = rpc_run_task(&task_setup_data);
+        if (IS_ERR(task))
+                status = PTR_ERR(task);
+        rpc_put_task(task);
+out:
+        dprintk("<-- %s status=%d\n", __func__, status);
+        return status;
+}
 #endif /* CONFIG_NFS_V4_1 */
 
 struct nfs4_state_recovery_ops nfs40_reboot_recovery_ops = {
@@ -4990,6 +5094,7 @@ struct nfs4_state_recovery_ops nfs41_reboot_recovery_ops = {
         .recover_lock   = nfs4_lock_reclaim,
         .establish_clid = nfs41_init_clientid,
         .get_clid_cred  = nfs4_get_exchange_id_cred,
+        .reclaim_complete = nfs41_proc_reclaim_complete,
 };
 #endif /* CONFIG_NFS_V4_1 */
 
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index bc4ca6f4d8c6..f2d2dc497551 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1032,6 +1032,14 @@ static void nfs4_state_start_reclaim_reboot(struct nfs_client *clp)
         nfs4_state_mark_reclaim_helper(clp, nfs4_state_mark_reclaim_reboot);
 }
 
+static void nfs4_reclaim_complete(struct nfs_client *clp,
+                                 const struct nfs4_state_recovery_ops *ops)
+{
+        /* Notify the server we're done reclaiming our state */
+        if (ops->reclaim_complete)
+                (void)ops->reclaim_complete(clp);
+}
+
 static void nfs4_state_end_reclaim_reboot(struct nfs_client *clp)
 {
         struct nfs4_state_owner *sp;