knfsd: spawn kernel thread to probe callback channel

[safe/jmp/linux-2.6] / fs / nfsd / nfs4callback.c

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 31d6633..c17a520 100644 (file)
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -39,6 +39,7 @@
 #include <linux/errno.h>
 #include <linux/delay.h>
 #include <linux/sched.h>
+#include <linux/kthread.h>
 #include <linux/sunrpc/xdr.h>
 #include <linux/sunrpc/svc.h>
 #include <linux/sunrpc/clnt.h>
@@ -365,6 +366,35 @@ nfsd4_lookupcred(struct nfs4_client *clp, int taskflags)
         return ret;
 }
 
+/* Reference counting, callback cleanup, etc., all look racy as heck.
+ * And why is cb_set an atomic? */
+
+static int do_probe_callback(void *data)
+{
+       struct nfs4_client *clp = data;
+       struct nfs4_callback *cb = &clp->cl_callback;
+       struct rpc_message msg = {
+               .rpc_proc       = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL],
+               .rpc_argp       = clp,
+       };
+       int status;
+
+       msg.rpc_cred = nfsd4_lookupcred(clp, 0);
+       if (IS_ERR(msg.rpc_cred))
+               goto out;
+       status = rpc_call_sync(cb->cb_client, &msg, RPC_TASK_SOFT);
+       put_rpccred(msg.rpc_cred);
+
+       if (status) {
+               rpc_shutdown_client(cb->cb_client);
+               cb->cb_client = NULL;
+       } else
+               atomic_set(&cb->cb_set, 1);
+out:
+       put_nfs4_client(clp);
+       return 0;
+}
+
 /*
  * Set up the callback client and put a NFSPROC4_CB_NULL on the wire...
  */
@@ -390,11 +420,7 @@ nfsd4_probe_callback(struct nfs4_client *clp)
                .authflavor     = RPC_AUTH_UNIX,        /* XXX: need AUTH_GSS... */
                .flags          = (RPC_CLNT_CREATE_NOPING),
        };
-       struct rpc_message msg = {
-               .rpc_proc       = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL],
-               .rpc_argp       = clp,
-       };
-       int status;
+       struct task_struct *t;
 
        if (atomic_read(&cb->cb_set))
                return;
@@ -426,16 +452,11 @@ nfsd4_probe_callback(struct nfs4_client *clp)
        /* the task holds a reference to the nfs4_client struct */
        atomic_inc(&clp->cl_count);
 
-       msg.rpc_cred = nfsd4_lookupcred(clp,0);
-       if (IS_ERR(msg.rpc_cred))
-               goto out_release_clp;
-       status = rpc_call_async(cb->cb_client, &msg, RPC_TASK_ASYNC, &nfs4_cb_null_ops, NULL);
-       put_rpccred(msg.rpc_cred);
+       t = kthread_run(do_probe_callback, clp, "nfs4_cb_probe");
 
-       if (status != 0) {
-               dprintk("NFSD: asynchronous NFSPROC4_CB_NULL failed!\n");
+       if (IS_ERR(t))
                goto out_release_clp;
-       }
+
        return;
 
 out_release_clp:
@@ -447,30 +468,6 @@ out_err:
                (int)clp->cl_name.len, clp->cl_name.data);
 }
 
-static void
-nfs4_cb_null(struct rpc_task *task, void *dummy)
-{
-       struct nfs4_client *clp = (struct nfs4_client *)task->tk_msg.rpc_argp;
-       struct nfs4_callback *cb = &clp->cl_callback;
-       __be32 addr = htonl(cb->cb_addr);
-
-       dprintk("NFSD: nfs4_cb_null task->tk_status %d\n", task->tk_status);
-
-       if (task->tk_status < 0) {
-               dprintk("NFSD: callback establishment to client %.*s failed\n",
-                       (int)clp->cl_name.len, clp->cl_name.data);
-               goto out;
-       }
-       atomic_set(&cb->cb_set, 1);
-       dprintk("NFSD: callback set to client %u.%u.%u.%u\n", NIPQUAD(addr));
-out:
-       put_nfs4_client(clp);
-}
-
-static const struct rpc_call_ops nfs4_cb_null_ops = {
-       .rpc_call_done = nfs4_cb_null,
-};
-
 /*
  * called with dp->dl_count inc'ed.
  * nfs4_lock_state() may or may not have been called.