clnt.c

linux 内核源代码

	case -ETIMEDOUT:
		task->tk_action = call_timeout;
		return;
	}
	rpc_exit(task, -EIO);
}

/*
 * 5.	Transmit the RPC request, and wait for reply
 */
static void
call_transmit(struct rpc_task *task)
{
	dprint_status(task);

	task->tk_action = call_status;
	if (task->tk_status < 0)
		return;
	task->tk_status = xprt_prepare_transmit(task);
	if (task->tk_status != 0)
		return;
	task->tk_action = call_transmit_status;
	/* Encode here so that rpcsec_gss can use correct sequence number. */
	if (rpc_task_need_encode(task)) {
		BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
		call_encode(task);
		/* Did the encode result in an error condition? */
		if (task->tk_status != 0)
			return;
	}
	xprt_transmit(task);
	if (task->tk_status < 0)
		return;
	/*
	 * On success, ensure that we call xprt_end_transmit() before sleeping
	 * in order to allow access to the socket to other RPC requests.
	 */
	call_transmit_status(task);
	if (task->tk_msg.rpc_proc->p_decode != NULL)
		return;
	task->tk_action = rpc_exit_task;
	rpc_wake_up_task(task);
}

/*
 * 5a.	Handle cleanup after a transmission
 */
static void
call_transmit_status(struct rpc_task *task)
{
	task->tk_action = call_status;
	/*
	 * Special case: if we've been waiting on the socket's write_space()
	 * callback, then don't call xprt_end_transmit().
	 */
	if (task->tk_status == -EAGAIN)
		return;
	xprt_end_transmit(task);
	rpc_task_force_reencode(task);
}

/*
 * 6.	Sort out the RPC call status
 */
static void
call_status(struct rpc_task *task)
{
	struct rpc_clnt	*clnt = task->tk_client;
	struct rpc_rqst	*req = task->tk_rqstp;
	int		status;

	if (req->rq_received > 0 && !req->rq_bytes_sent)
		task->tk_status = req->rq_received;

	dprint_status(task);

	status = task->tk_status;
	if (status >= 0) {
		task->tk_action = call_decode;
		return;
	}

	task->tk_status = 0;
	switch(status) {
	case -EHOSTDOWN:
	case -EHOSTUNREACH:
	case -ENETUNREACH:
		/*
		 * Delay any retries for 3 seconds, then handle as if it
		 * were a timeout.
		 */
		rpc_delay(task, 3*HZ);
	case -ETIMEDOUT:
		task->tk_action = call_timeout;
		if (task->tk_client->cl_discrtry)
			xprt_disconnect(task->tk_xprt);
		break;
	case -ECONNREFUSED:
	case -ENOTCONN:
		rpc_force_rebind(clnt);
		task->tk_action = call_bind;
		break;
	case -EAGAIN:
		task->tk_action = call_transmit;
		break;
	case -EIO:
		/* shutdown or soft timeout */
		rpc_exit(task, status);
		break;
	default:
		printk("%s: RPC call returned error %d\n",
			       clnt->cl_protname, -status);
		rpc_exit(task, status);
	}
}

/*
 * 6a.	Handle RPC timeout
 * 	We do not release the request slot, so we keep using the
 *	same XID for all retransmits.
 */
static void
call_timeout(struct rpc_task *task)
{
	struct rpc_clnt	*clnt = task->tk_client;

	if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
		dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
		goto retry;
	}

	dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
	task->tk_timeouts++;

	if (RPC_IS_SOFT(task)) {
		printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
				clnt->cl_protname, clnt->cl_server);
		rpc_exit(task, -EIO);
		return;
	}

	if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
		task->tk_flags |= RPC_CALL_MAJORSEEN;
		printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
			clnt->cl_protname, clnt->cl_server);
	}
	rpc_force_rebind(clnt);

retry:
	clnt->cl_stats->rpcretrans++;
	task->tk_action = call_bind;
	task->tk_status = 0;
}

/*
 * 7.	Decode the RPC reply
 */
static void
call_decode(struct rpc_task *task)
{
	struct rpc_clnt	*clnt = task->tk_client;
	struct rpc_rqst	*req = task->tk_rqstp;
	kxdrproc_t	decode = task->tk_msg.rpc_proc->p_decode;
	__be32		*p;

	dprintk("RPC: %5u call_decode (status %d)\n",
			task->tk_pid, task->tk_status);

	if (task->tk_flags & RPC_CALL_MAJORSEEN) {
		printk(KERN_NOTICE "%s: server %s OK\n",
			clnt->cl_protname, clnt->cl_server);
		task->tk_flags &= ~RPC_CALL_MAJORSEEN;
	}

	if (task->tk_status < 12) {
		if (!RPC_IS_SOFT(task)) {
			task->tk_action = call_bind;
			clnt->cl_stats->rpcretrans++;
			goto out_retry;
		}
		dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
				clnt->cl_protname, task->tk_status);
		task->tk_action = call_timeout;
		goto out_retry;
	}

	/*
	 * Ensure that we see all writes made by xprt_complete_rqst()
	 * before it changed req->rq_received.
	 */
	smp_rmb();
	req->rq_rcv_buf.len = req->rq_private_buf.len;

	/* Check that the softirq receive buffer is valid */
	WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
				sizeof(req->rq_rcv_buf)) != 0);

	/* Verify the RPC header */
	p = call_verify(task);
	if (IS_ERR(p)) {
		if (p == ERR_PTR(-EAGAIN))
			goto out_retry;
		return;
	}

	task->tk_action = rpc_exit_task;

	if (decode) {
		task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
						      task->tk_msg.rpc_resp);
	}
	dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
			task->tk_status);
	return;
out_retry:
	req->rq_received = req->rq_private_buf.len = 0;
	task->tk_status = 0;
	if (task->tk_client->cl_discrtry)
		xprt_disconnect(task->tk_xprt);
}

/*
 * 8.	Refresh the credentials if rejected by the server
 */
static void
call_refresh(struct rpc_task *task)
{
	dprint_status(task);

	task->tk_action = call_refreshresult;
	task->tk_status = 0;
	task->tk_client->cl_stats->rpcauthrefresh++;
	rpcauth_refreshcred(task);
}

/*
 * 8a.	Process the results of a credential refresh
 */
static void
call_refreshresult(struct rpc_task *task)
{
	int status = task->tk_status;

	dprint_status(task);

	task->tk_status = 0;
	task->tk_action = call_reserve;
	if (status >= 0 && rpcauth_uptodatecred(task))
		return;
	if (status == -EACCES) {
		rpc_exit(task, -EACCES);
		return;
	}
	task->tk_action = call_refresh;
	if (status != -ETIMEDOUT)
		rpc_delay(task, 3*HZ);
	return;
}

/*
 * Call header serialization
 */
static __be32 *
call_header(struct rpc_task *task)
{
	struct rpc_clnt *clnt = task->tk_client;
	struct rpc_rqst	*req = task->tk_rqstp;
	__be32		*p = req->rq_svec[0].iov_base;

	/* FIXME: check buffer size? */

	p = xprt_skip_transport_header(task->tk_xprt, p);
	*p++ = req->rq_xid;		/* XID */
	*p++ = htonl(RPC_CALL);		/* CALL */
	*p++ = htonl(RPC_VERSION);	/* RPC version */
	*p++ = htonl(clnt->cl_prog);	/* program number */
	*p++ = htonl(clnt->cl_vers);	/* program version */
	*p++ = htonl(task->tk_msg.rpc_proc->p_proc);	/* procedure */
	p = rpcauth_marshcred(task, p);
	req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
	return p;
}

/*
 * Reply header verification
 */
static __be32 *
call_verify(struct rpc_task *task)
{
	struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
	int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
	__be32	*p = iov->iov_base;
	u32 n;
	int error = -EACCES;

	if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
		/* RFC-1014 says that the representation of XDR data must be a
		 * multiple of four bytes
		 * - if it isn't pointer subtraction in the NFS client may give
		 *   undefined results
		 */
		dprintk("RPC: %5u %s: XDR representation not a multiple of"
		       " 4 bytes: 0x%x\n", task->tk_pid, __FUNCTION__,
		       task->tk_rqstp->rq_rcv_buf.len);
		goto out_eio;
	}
	if ((len -= 3) < 0)
		goto out_overflow;
	p += 1;	/* skip XID */

	if ((n = ntohl(*p++)) != RPC_REPLY) {
		dprintk("RPC: %5u %s: not an RPC reply: %x\n",
				task->tk_pid, __FUNCTION__, n);
		goto out_garbage;
	}
	if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
		if (--len < 0)
			goto out_overflow;
		switch ((n = ntohl(*p++))) {
			case RPC_AUTH_ERROR:
				break;
			case RPC_MISMATCH:
				dprintk("RPC: %5u %s: RPC call version "
						"mismatch!\n",
						task->tk_pid, __FUNCTION__);
				error = -EPROTONOSUPPORT;
				goto out_err;
			default:
				dprintk("RPC: %5u %s: RPC call rejected, "
						"unknown error: %x\n",
						task->tk_pid, __FUNCTION__, n);
				goto out_eio;
		}
		if (--len < 0)
			goto out_overflow;
		switch ((n = ntohl(*p++))) {
		case RPC_AUTH_REJECTEDCRED:
		case RPC_AUTH_REJECTEDVERF:
		case RPCSEC_GSS_CREDPROBLEM:
		case RPCSEC_GSS_CTXPROBLEM:
			if (!task->tk_cred_retry)
				break;
			task->tk_cred_retry--;
			dprintk("RPC: %5u %s: retry stale creds\n",
					task->tk_pid, __FUNCTION__);
			rpcauth_invalcred(task);
			/* Ensure we obtain a new XID! */
			xprt_release(task);
			task->tk_action = call_refresh;
			goto out_retry;
		case RPC_AUTH_BADCRED:
		case RPC_AUTH_BADVERF:
			/* possibly garbled cred/verf? */
			if (!task->tk_garb_retry)
				break;
			task->tk_garb_retry--;
			dprintk("RPC: %5u %s: retry garbled creds\n",
					task->tk_pid, __FUNCTION__);
			task->tk_action = call_bind;
			goto out_retry;
		case RPC_AUTH_TOOWEAK:
			printk(KERN_NOTICE "call_verify: server %s requires stronger "
			       "authentication.\n", task->tk_client->cl_server);
			break;
		default:
			dprintk("RPC: %5u %s: unknown auth error: %x\n",
					task->tk_pid, __FUNCTION__, n);
			error = -EIO;
		}
		dprintk("RPC: %5u %s: call rejected %d\n",
				task->tk_pid, __FUNCTION__, n);
		goto out_err;
	}
	if (!(p = rpcauth_checkverf(task, p))) {
		dprintk("RPC: %5u %s: auth check failed\n",
				task->tk_pid, __FUNCTION__);
		goto out_garbage;		/* bad verifier, retry */
	}
	len = p - (__be32 *)iov->iov_base - 1;
	if (len < 0)
		goto out_overflow;
	switch ((n = ntohl(*p++))) {
	case RPC_SUCCESS:
		return p;
	case RPC_PROG_UNAVAIL:
		dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
				task->tk_pid, __FUNCTION__,
				(unsigned int)task->tk_client->cl_prog,
				task->tk_client->cl_server);
		error = -EPFNOSUPPORT;
		goto out_err;
	case RPC_PROG_MISMATCH:
		dprintk("RPC: %5u %s: program %u, version %u unsupported by "
				"server %s\n", task->tk_pid, __FUNCTION__,
				(unsigned int)task->tk_client->cl_prog,
				(unsigned int)task->tk_client->cl_vers,
				task->tk_client->cl_server);
		error = -EPROTONOSUPPORT;
		goto out_err;
	case RPC_PROC_UNAVAIL:
		dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
				"version %u on server %s\n",
				task->tk_pid, __FUNCTION__,
				task->tk_msg.rpc_proc,
				task->tk_client->cl_prog,
				task->tk_client->cl_vers,
				task->tk_client->cl_server);
		error = -EOPNOTSUPP;
		goto out_err;
	case RPC_GARBAGE_ARGS:
		dprintk("RPC: %5u %s: server saw garbage\n",
				task->tk_pid, __FUNCTION__);
		break;			/* retry */
	default:
		dprintk("RPC: %5u %s: server accept status: %x\n",
				task->tk_pid, __FUNCTION__, n);
		/* Also retry */
	}

out_garbage:
	task->tk_client->cl_stats->rpcgarbage++;
	if (task->tk_garb_retry) {
		task->tk_garb_retry--;
		dprintk("RPC: %5u %s: retrying\n",
				task->tk_pid, __FUNCTION__);
		task->tk_action = call_bind;
out_retry:
		return ERR_PTR(-EAGAIN);
	}
out_eio:
	error = -EIO;
out_err:
	rpc_exit(task, error);
	dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
			__FUNCTION__, error);
	return ERR_PTR(error);
out_overflow:
	dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
			__FUNCTION__);
	goto out_garbage;
}

static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
{
	return 0;
}

static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
{
	return 0;
}

static struct rpc_procinfo rpcproc_null = {
	.p_encode = rpcproc_encode_null,
	.p_decode = rpcproc_decode_null,
};

static int rpc_ping(struct rpc_clnt *clnt, int flags)
{
	struct rpc_message msg = {
		.rpc_proc = &rpcproc_null,
	};
	int err;
	msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
	err = rpc_call_sync(clnt, &msg, flags);
	put_rpccred(msg.rpc_cred);
	return err;
}

struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
{
	struct rpc_message msg = {
		.rpc_proc = &rpcproc_null,
		.rpc_cred = cred,
	};
	return rpc_do_run_task(clnt, &msg, flags, &rpc_default_ops, NULL);
}
EXPORT_SYMBOL(rpc_call_null);

#ifdef RPC_DEBUG
void rpc_show_tasks(void)
{
	struct rpc_clnt *clnt;
	struct rpc_task *t;

	spin_lock(&rpc_client_lock);
	if (list_empty(&all_clients))
		goto out;
	printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
		"-rpcwait -action- ---ops--\n");
	list_for_each_entry(clnt, &all_clients, cl_clients) {
		if (list_empty(&clnt->cl_tasks))
			continue;
		spin_lock(&clnt->cl_lock);
		list_for_each_entry(t, &clnt->cl_tasks, tk_task) {
			const char *rpc_waitq = "none";
			int proc;

			if (t->tk_msg.rpc_proc)
				proc = t->tk_msg.rpc_proc->p_proc;
			else
				proc = -1;

			if (RPC_IS_QUEUED(t))
				rpc_waitq = rpc_qname(t->u.tk_wait.rpc_waitq);

			printk("%5u %04d %04x %6d %8p %6d %8p %8ld %8s %8p %8p\n",
				t->tk_pid, proc,
				t->tk_flags, t->tk_status,
				t->tk_client,
				(t->tk_client ? t->tk_client->cl_prog : 0),
				t->tk_rqstp, t->tk_timeout,
				rpc_waitq,
				t->tk_action, t->tk_ops);
		}
		spin_unlock(&clnt->cl_lock);
	}
out:
	spin_unlock(&rpc_client_lock);
}
#endif