Initial import

1 files changed, 1113 insertions, 0 deletions

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
new file mode 100644
index 000000000..126f46b88
--- /dev/null
+++ b/fs/cifs/transport.c
@@ -0,0 +1,1113 @@
+/*
+ *   fs/cifs/transport.c
+ *
+ *   Copyright (C) International Business Machines  Corp., 2002,2008
+ *   Author(s): Steve French (sfrench@us.ibm.com)
+ *   Jeremy Allison (jra@samba.org) 2006.
+ *
+ *   This library is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU Lesser General Public License as published
+ *   by the Free Software Foundation; either version 2.1 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This library is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+ *   the GNU Lesser General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Lesser General Public License
+ *   along with this library; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/gfp.h>
+#include <linux/wait.h>
+#include <linux/net.h>
+#include <linux/delay.h>
+#include <linux/freezer.h>
+#include <linux/tcp.h>
+#include <linux/highmem.h>
+#include <asm/uaccess.h>
+#include <asm/processor.h>
+#include <linux/mempool.h>
+#include "cifspdu.h"
+#include "cifsglob.h"
+#include "cifsproto.h"
+#include "cifs_debug.h"
+
+void
+cifs_wake_up_task(struct mid_q_entry *mid)
+{
+	wake_up_process(mid->callback_data);
+}
+
+struct mid_q_entry *
+AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
+{
+	struct mid_q_entry *temp;
+
+	if (server == NULL) {
+		cifs_dbg(VFS, "Null TCP session in AllocMidQEntry\n");
+		return NULL;
+	}
+
+	temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
+	if (temp == NULL)
+		return temp;
+	else {
+		memset(temp, 0, sizeof(struct mid_q_entry));
+		temp->mid = get_mid(smb_buffer);
+		temp->pid = current->pid;
+		temp->command = cpu_to_le16(smb_buffer->Command);
+		cifs_dbg(FYI, "For smb_command %d\n", smb_buffer->Command);
+	/*	do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */
+		/* when mid allocated can be before when sent */
+		temp->when_alloc = jiffies;
+		temp->server = server;
+
+		/*
+		 * The default is for the mid to be synchronous, so the
+		 * default callback just wakes up the current task.
+		 */
+		temp->callback = cifs_wake_up_task;
+		temp->callback_data = current;
+	}
+
+	atomic_inc(&midCount);
+	temp->mid_state = MID_REQUEST_ALLOCATED;
+	return temp;
+}
+
+void
+DeleteMidQEntry(struct mid_q_entry *midEntry)
+{
+#ifdef CONFIG_CIFS_STATS2
+	__le16 command = midEntry->server->vals->lock_cmd;
+	unsigned long now;
+#endif
+	midEntry->mid_state = MID_FREE;
+	atomic_dec(&midCount);
+	if (midEntry->large_buf)
+		cifs_buf_release(midEntry->resp_buf);
+	else
+		cifs_small_buf_release(midEntry->resp_buf);
+#ifdef CONFIG_CIFS_STATS2
+	now = jiffies;
+	/* commands taking longer than one second are indications that
+	   something is wrong, unless it is quite a slow link or server */
+	if ((now - midEntry->when_alloc) > HZ) {
+		if ((cifsFYI & CIFS_TIMER) && (midEntry->command != command)) {
+			pr_debug(" CIFS slow rsp: cmd %d mid %llu",
+			       midEntry->command, midEntry->mid);
+			pr_info(" A: 0x%lx S: 0x%lx R: 0x%lx\n",
+			       now - midEntry->when_alloc,
+			       now - midEntry->when_sent,
+			       now - midEntry->when_received);
+		}
+	}
+#endif
+	mempool_free(midEntry, cifs_mid_poolp);
+}
+
+void
+cifs_delete_mid(struct mid_q_entry *mid)
+{
+	spin_lock(&GlobalMid_Lock);
+	list_del(&mid->qhead);
+	spin_unlock(&GlobalMid_Lock);
+
+	DeleteMidQEntry(mid);
+}
+
+/*
+ * smb_send_kvec - send an array of kvecs to the server
+ * @server:	Server to send the data to
+ * @iov:	Pointer to array of kvecs
+ * @n_vec:	length of kvec array
+ * @sent:	amount of data sent on socket is stored here
+ *
+ * Our basic "send data to server" function. Should be called with srv_mutex
+ * held. The caller is responsible for handling the results.
+ */
+static int
+smb_send_kvec(struct TCP_Server_Info *server, struct kvec *iov, size_t n_vec,
+		size_t *sent)
+{
+	int rc = 0;
+	int i = 0;
+	struct msghdr smb_msg;
+	unsigned int remaining;
+	size_t first_vec = 0;
+	struct socket *ssocket = server->ssocket;
+
+	*sent = 0;
+
+	smb_msg.msg_name = (struct sockaddr *) &server->dstaddr;
+	smb_msg.msg_namelen = sizeof(struct sockaddr);
+	smb_msg.msg_control = NULL;
+	smb_msg.msg_controllen = 0;
+	if (server->noblocksnd)
+		smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL;
+	else
+		smb_msg.msg_flags = MSG_NOSIGNAL;
+
+	remaining = 0;
+	for (i = 0; i < n_vec; i++)
+		remaining += iov[i].iov_len;
+
+	i = 0;
+	while (remaining) {
+		/*
+		 * If blocking send, we try 3 times, since each can block
+		 * for 5 seconds. For nonblocking  we have to try more
+		 * but wait increasing amounts of time allowing time for
+		 * socket to clear.  The overall time we wait in either
+		 * case to send on the socket is about 15 seconds.
+		 * Similarly we wait for 15 seconds for a response from
+		 * the server in SendReceive[2] for the server to send
+		 * a response back for most types of requests (except
+		 * SMB Write past end of file which can be slow, and
+		 * blocking lock operations). NFS waits slightly longer
+		 * than CIFS, but this can make it take longer for
+		 * nonresponsive servers to be detected and 15 seconds
+		 * is more than enough time for modern networks to
+		 * send a packet.  In most cases if we fail to send
+		 * after the retries we will kill the socket and
+		 * reconnect which may clear the network problem.
+		 */
+		rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
+				    n_vec - first_vec, remaining);
+		if (rc == -EAGAIN) {
+			i++;
+			if (i >= 14 || (!server->noblocksnd && (i > 2))) {
+				cifs_dbg(VFS, "sends on sock %p stuck for 15 seconds\n",
+					 ssocket);
+				rc = -EAGAIN;
+				break;
+			}
+			msleep(1 << i);
+			continue;
+		}
+
+		if (rc < 0)
+			break;
+
+		/* send was at least partially successful */
+		*sent += rc;
+
+		if (rc == remaining) {
+			remaining = 0;
+			break;
+		}
+
+		if (rc > remaining) {
+			cifs_dbg(VFS, "sent %d requested %d\n", rc, remaining);
+			break;
+		}
+
+		if (rc == 0) {
+			/* should never happen, letting socket clear before
+			   retrying is our only obvious option here */
+			cifs_dbg(VFS, "tcp sent no data\n");
+			msleep(500);
+			continue;
+		}
+
+		remaining -= rc;
+
+		/* the line below resets i */
+		for (i = first_vec; i < n_vec; i++) {
+			if (iov[i].iov_len) {
+				if (rc > iov[i].iov_len) {
+					rc -= iov[i].iov_len;
+					iov[i].iov_len = 0;
+				} else {
+					iov[i].iov_base += rc;
+					iov[i].iov_len -= rc;
+					first_vec = i;
+					break;
+				}
+			}
+		}
+
+		i = 0; /* in case we get ENOSPC on the next send */
+		rc = 0;
+	}
+	return rc;
+}
+
+/**
+ * rqst_page_to_kvec - Turn a slot in the smb_rqst page array into a kvec
+ * @rqst: pointer to smb_rqst
+ * @idx: index into the array of the page
+ * @iov: pointer to struct kvec that will hold the result
+ *
+ * Helper function to convert a slot in the rqst->rq_pages array into a kvec.
+ * The page will be kmapped and the address placed into iov_base. The length
+ * will then be adjusted according to the ptailoff.
+ */
+void
+cifs_rqst_page_to_kvec(struct smb_rqst *rqst, unsigned int idx,
+			struct kvec *iov)
+{
+	/*
+	 * FIXME: We could avoid this kmap altogether if we used
+	 * kernel_sendpage instead of kernel_sendmsg. That will only
+	 * work if signing is disabled though as sendpage inlines the
+	 * page directly into the fraglist. If userspace modifies the
+	 * page after we calculate the signature, then the server will
+	 * reject it and may break the connection. kernel_sendmsg does
+	 * an extra copy of the data and avoids that issue.
+	 */
+	iov->iov_base = kmap(rqst->rq_pages[idx]);
+
+	/* if last page, don't send beyond this offset into page */
+	if (idx == (rqst->rq_npages - 1))
+		iov->iov_len = rqst->rq_tailsz;
+	else
+		iov->iov_len = rqst->rq_pagesz;
+}
+
+static unsigned long
+rqst_len(struct smb_rqst *rqst)
+{
+	unsigned int i;
+	struct kvec *iov = rqst->rq_iov;
+	unsigned long buflen = 0;
+
+	/* total up iov array first */
+	for (i = 0; i < rqst->rq_nvec; i++)
+		buflen += iov[i].iov_len;
+
+	/* add in the page array if there is one */
+	if (rqst->rq_npages) {
+		buflen += rqst->rq_pagesz * (rqst->rq_npages - 1);
+		buflen += rqst->rq_tailsz;
+	}
+
+	return buflen;
+}
+
+static int
+smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
+{
+	int rc;
+	struct kvec *iov = rqst->rq_iov;
+	int n_vec = rqst->rq_nvec;
+	unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);
+	unsigned long send_length;
+	unsigned int i;
+	size_t total_len = 0, sent;
+	struct socket *ssocket = server->ssocket;
+	int val = 1;
+
+	if (ssocket == NULL)
+		return -ENOTSOCK;
+
+	/* sanity check send length */
+	send_length = rqst_len(rqst);
+	if (send_length != smb_buf_length + 4) {
+		WARN(1, "Send length mismatch(send_length=%lu smb_buf_length=%u)\n",
+			send_length, smb_buf_length);
+		return -EIO;
+	}
+
+	cifs_dbg(FYI, "Sending smb: smb_len=%u\n", smb_buf_length);
+	dump_smb(iov[0].iov_base, iov[0].iov_len);
+
+	/* cork the socket */
+	kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
+				(char *)&val, sizeof(val));
+
+	rc = smb_send_kvec(server, iov, n_vec, &sent);
+	if (rc < 0)
+		goto uncork;
+
+	total_len += sent;
+
+	/* now walk the page array and send each page in it */
+	for (i = 0; i < rqst->rq_npages; i++) {
+		struct kvec p_iov;
+
+		cifs_rqst_page_to_kvec(rqst, i, &p_iov);
+		rc = smb_send_kvec(server, &p_iov, 1, &sent);
+		kunmap(rqst->rq_pages[i]);
+		if (rc < 0)
+			break;
+
+		total_len += sent;
+	}
+
+uncork:
+	/* uncork it */
+	val = 0;
+	kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
+				(char *)&val, sizeof(val));
+
+	if ((total_len > 0) && (total_len != smb_buf_length + 4)) {
+		cifs_dbg(FYI, "partial send (wanted=%u sent=%zu): terminating session\n",
+			 smb_buf_length + 4, total_len);
+		/*
+		 * If we have only sent part of an SMB then the next SMB could
+		 * be taken as the remainder of this one. We need to kill the
+		 * socket so the server throws away the partial SMB
+		 */
+		server->tcpStatus = CifsNeedReconnect;
+	}
+
+	if (rc < 0 && rc != -EINTR)
+		cifs_dbg(VFS, "Error %d sending data on socket to server\n",
+			 rc);
+	else
+		rc = 0;
+
+	return rc;
+}
+
+static int
+smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
+{
+	struct smb_rqst rqst = { .rq_iov = iov,
+				 .rq_nvec = n_vec };
+
+	return smb_send_rqst(server, &rqst);
+}
+
+int
+smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
+	 unsigned int smb_buf_length)
+{
+	struct kvec iov;
+
+	iov.iov_base = smb_buffer;
+	iov.iov_len = smb_buf_length + 4;
+
+	return smb_sendv(server, &iov, 1);
+}
+
+static int
+wait_for_free_credits(struct TCP_Server_Info *server, const int timeout,
+		      int *credits)
+{
+	int rc;
+
+	spin_lock(&server->req_lock);
+	if (timeout == CIFS_ASYNC_OP) {
+		/* oplock breaks must not be held up */
+		server->in_flight++;
+		*credits -= 1;
+		spin_unlock(&server->req_lock);
+		return 0;
+	}
+
+	while (1) {
+		if (*credits <= 0) {
+			spin_unlock(&server->req_lock);
+			cifs_num_waiters_inc(server);
+			rc = wait_event_killable(server->request_q,
+						 has_credits(server, credits));
+			cifs_num_waiters_dec(server);
+			if (rc)
+				return rc;
+			spin_lock(&server->req_lock);
+		} else {
+			if (server->tcpStatus == CifsExiting) {
+				spin_unlock(&server->req_lock);
+				return -ENOENT;
+			}
+
+			/*
+			 * Can not count locking commands against total
+			 * as they are allowed to block on server.
+			 */
+
+			/* update # of requests on the wire to server */
+			if (timeout != CIFS_BLOCKING_OP) {
+				*credits -= 1;
+				server->in_flight++;
+			}
+			spin_unlock(&server->req_lock);
+			break;
+		}
+	}
+	return 0;
+}
+
+static int
+wait_for_free_request(struct TCP_Server_Info *server, const int timeout,
+		      const int optype)
+{
+	int *val;
+
+	val = server->ops->get_credits_field(server, optype);
+	/* Since an echo is already inflight, no need to wait to send another */
+	if (*val <= 0 && optype == CIFS_ECHO_OP)
+		return -EAGAIN;
+	return wait_for_free_credits(server, timeout, val);
+}
+
+int
+cifs_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size,
+		      unsigned int *num, unsigned int *credits)
+{
+	*num = size;
+	*credits = 0;
+	return 0;
+}
+
+static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,
+			struct mid_q_entry **ppmidQ)
+{
+	if (ses->server->tcpStatus == CifsExiting) {
+		return -ENOENT;
+	}
+
+	if (ses->server->tcpStatus == CifsNeedReconnect) {
+		cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
+		return -EAGAIN;
+	}
+
+	if (ses->status == CifsNew) {
+		if ((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
+			(in_buf->Command != SMB_COM_NEGOTIATE))
+			return -EAGAIN;
+		/* else ok - we are setting up session */
+	}
+
+	if (ses->status == CifsExiting) {
+		/* check if SMB session is bad because we are setting it up */
+		if (in_buf->Command != SMB_COM_LOGOFF_ANDX)
+			return -EAGAIN;
+		/* else ok - we are shutting down session */
+	}
+
+	*ppmidQ = AllocMidQEntry(in_buf, ses->server);
+	if (*ppmidQ == NULL)
+		return -ENOMEM;
+	spin_lock(&GlobalMid_Lock);
+	list_add_tail(&(*ppmidQ)->qhead, &ses->server->pending_mid_q);
+	spin_unlock(&GlobalMid_Lock);
+	return 0;
+}
+
+static int
+wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
+{
+	int error;
+
+	error = wait_event_freezekillable_unsafe(server->response_q,
+				    midQ->mid_state != MID_REQUEST_SUBMITTED);
+	if (error < 0)
+		return -ERESTARTSYS;
+
+	return 0;
+}
+
+struct mid_q_entry *
+cifs_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
+{
+	int rc;
+	struct smb_hdr *hdr = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
+	struct mid_q_entry *mid;
+
+	/* enable signing if server requires it */
+	if (server->sign)
+		hdr->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
+
+	mid = AllocMidQEntry(hdr, server);
+	if (mid == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	rc = cifs_sign_rqst(rqst, server, &mid->sequence_number);
+	if (rc) {
+		DeleteMidQEntry(mid);
+		return ERR_PTR(rc);
+	}
+
+	return mid;
+}
+
+/*
+ * Send a SMB request and set the callback function in the mid to handle
+ * the result. Caller is responsible for dealing with timeouts.
+ */
+int
+cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,
+		mid_receive_t *receive, mid_callback_t *callback,
+		void *cbdata, const int flags)
+{
+	int rc, timeout, optype;
+	struct mid_q_entry *mid;
+	unsigned int credits = 0;
+
+	timeout = flags & CIFS_TIMEOUT_MASK;
+	optype = flags & CIFS_OP_MASK;
+
+	if ((flags & CIFS_HAS_CREDITS) == 0) {
+		rc = wait_for_free_request(server, timeout, optype);
+		if (rc)
+			return rc;
+		credits = 1;
+	}
+
+	mutex_lock(&server->srv_mutex);
+	mid = server->ops->setup_async_request(server, rqst);
+	if (IS_ERR(mid)) {
+		mutex_unlock(&server->srv_mutex);
+		add_credits_and_wake_if(server, credits, optype);
+		return PTR_ERR(mid);
+	}
+
+	mid->receive = receive;
+	mid->callback = callback;
+	mid->callback_data = cbdata;
+	mid->mid_state = MID_REQUEST_SUBMITTED;
+
+	/* put it on the pending_mid_q */
+	spin_lock(&GlobalMid_Lock);
+	list_add_tail(&mid->qhead, &server->pending_mid_q);
+	spin_unlock(&GlobalMid_Lock);
+
+
+	cifs_in_send_inc(server);
+	rc = smb_send_rqst(server, rqst);
+	cifs_in_send_dec(server);
+	cifs_save_when_sent(mid);
+
+	if (rc < 0)
+		server->sequence_number -= 2;
+	mutex_unlock(&server->srv_mutex);
+
+	if (rc == 0)
+		return 0;
+
+	cifs_delete_mid(mid);
+	add_credits_and_wake_if(server, credits, optype);
+	return rc;
+}
+
+/*
+ *
+ * Send an SMB Request.  No response info (other than return code)
+ * needs to be parsed.
+ *
+ * flags indicate the type of request buffer and how long to wait
+ * and whether to log NT STATUS code (error) before mapping it to POSIX error
+ *
+ */
+int
+SendReceiveNoRsp(const unsigned int xid, struct cifs_ses *ses,
+		 char *in_buf, int flags)
+{
+	int rc;
+	struct kvec iov[1];
+	int resp_buf_type;
+
+	iov[0].iov_base = in_buf;
+	iov[0].iov_len = get_rfc1002_length(in_buf) + 4;
+	flags |= CIFS_NO_RESP;
+	rc = SendReceive2(xid, ses, iov, 1, &resp_buf_type, flags);
+	cifs_dbg(NOISY, "SendRcvNoRsp flags %d rc %d\n", flags, rc);
+
+	return rc;
+}
+
+static int
+cifs_sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
+{
+	int rc = 0;
+
+	cifs_dbg(FYI, "%s: cmd=%d mid=%llu state=%d\n",
+		 __func__, le16_to_cpu(mid->command), mid->mid, mid->mid_state);
+
+	spin_lock(&GlobalMid_Lock);
+	switch (mid->mid_state) {
+	case MID_RESPONSE_RECEIVED:
+		spin_unlock(&GlobalMid_Lock);
+		return rc;
+	case MID_RETRY_NEEDED:
+		rc = -EAGAIN;
+		break;
+	case MID_RESPONSE_MALFORMED:
+		rc = -EIO;
+		break;
+	case MID_SHUTDOWN:
+		rc = -EHOSTDOWN;
+		break;
+	default:
+		list_del_init(&mid->qhead);
+		cifs_dbg(VFS, "%s: invalid mid state mid=%llu state=%d\n",
+			 __func__, mid->mid, mid->mid_state);
+		rc = -EIO;
+	}
+	spin_unlock(&GlobalMid_Lock);
+
+	DeleteMidQEntry(mid);
+	return rc;
+}
+
+static inline int
+send_cancel(struct TCP_Server_Info *server, void *buf, struct mid_q_entry *mid)
+{
+	return server->ops->send_cancel ?
+				server->ops->send_cancel(server, buf, mid) : 0;
+}
+
+int
+cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
+		   bool log_error)
+{
+	unsigned int len = get_rfc1002_length(mid->resp_buf) + 4;
+
+	dump_smb(mid->resp_buf, min_t(u32, 92, len));
+
+	/* convert the length into a more usable form */
+	if (server->sign) {
+		struct kvec iov;
+		int rc = 0;
+		struct smb_rqst rqst = { .rq_iov = &iov,
+					 .rq_nvec = 1 };
+
+		iov.iov_base = mid->resp_buf;
+		iov.iov_len = len;
+		/* FIXME: add code to kill session */
+		rc = cifs_verify_signature(&rqst, server,
+					   mid->sequence_number);
+		if (rc)
+			cifs_dbg(VFS, "SMB signature verification returned error = %d\n",
+				 rc);
+	}
+
+	/* BB special case reconnect tid and uid here? */
+	return map_smb_to_linux_error(mid->resp_buf, log_error);
+}
+
+struct mid_q_entry *
+cifs_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
+{
+	int rc;
+	struct smb_hdr *hdr = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
+	struct mid_q_entry *mid;
+
+	rc = allocate_mid(ses, hdr, &mid);
+	if (rc)
+		return ERR_PTR(rc);
+	rc = cifs_sign_rqst(rqst, ses->server, &mid->sequence_number);
+	if (rc) {
+		cifs_delete_mid(mid);
+		return ERR_PTR(rc);
+	}
+	return mid;
+}
+
+int
+SendReceive2(const unsigned int xid, struct cifs_ses *ses,
+	     struct kvec *iov, int n_vec, int *resp_buf_type /* ret */,
+	     const int flags)
+{
+	int rc = 0;
+	int timeout, optype;
+	struct mid_q_entry *midQ;
+	char *buf = iov[0].iov_base;
+	unsigned int credits = 1;
+	struct smb_rqst rqst = { .rq_iov = iov,
+				 .rq_nvec = n_vec };
+
+	timeout = flags & CIFS_TIMEOUT_MASK;
+	optype = flags & CIFS_OP_MASK;
+
+	*resp_buf_type = CIFS_NO_BUFFER;  /* no response buf yet */
+
+	if ((ses == NULL) || (ses->server == NULL)) {
+		cifs_small_buf_release(buf);
+		cifs_dbg(VFS, "Null session\n");
+		return -EIO;
+	}
+
+	if (ses->server->tcpStatus == CifsExiting) {
+		cifs_small_buf_release(buf);
+		return -ENOENT;
+	}
+
+	/*
+	 * Ensure that we do not send more than 50 overlapping requests
+	 * to the same server. We may make this configurable later or
+	 * use ses->maxReq.
+	 */
+
+	rc = wait_for_free_request(ses->server, timeout, optype);
+	if (rc) {
+		cifs_small_buf_release(buf);
+		return rc;
+	}
+
+	/*
+	 * Make sure that we sign in the same order that we send on this socket
+	 * and avoid races inside tcp sendmsg code that could cause corruption
+	 * of smb data.
+	 */
+
+	mutex_lock(&ses->server->srv_mutex);
+
+	midQ = ses->server->ops->setup_request(ses, &rqst);
+	if (IS_ERR(midQ)) {
+		mutex_unlock(&ses->server->srv_mutex);
+		cifs_small_buf_release(buf);
+		/* Update # of requests on wire to server */
+		add_credits(ses->server, 1, optype);
+		return PTR_ERR(midQ);
+	}
+
+	midQ->mid_state = MID_REQUEST_SUBMITTED;
+	cifs_in_send_inc(ses->server);
+	rc = smb_sendv(ses->server, iov, n_vec);
+	cifs_in_send_dec(ses->server);
+	cifs_save_when_sent(midQ);
+
+	if (rc < 0)
+		ses->server->sequence_number -= 2;
+	mutex_unlock(&ses->server->srv_mutex);
+
+	if (rc < 0) {
+		cifs_small_buf_release(buf);
+		goto out;
+	}
+
+	if (timeout == CIFS_ASYNC_OP) {
+		cifs_small_buf_release(buf);
+		goto out;
+	}
+
+	rc = wait_for_response(ses->server, midQ);
+	if (rc != 0) {
+		send_cancel(ses->server, buf, midQ);
+		spin_lock(&GlobalMid_Lock);
+		if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
+			midQ->callback = DeleteMidQEntry;
+			spin_unlock(&GlobalMid_Lock);
+			cifs_small_buf_release(buf);
+			add_credits(ses->server, 1, optype);
+			return rc;
+		}
+		spin_unlock(&GlobalMid_Lock);
+	}
+
+	cifs_small_buf_release(buf);
+
+	rc = cifs_sync_mid_result(midQ, ses->server);
+	if (rc != 0) {
+		add_credits(ses->server, 1, optype);
+		return rc;
+	}
+
+	if (!midQ->resp_buf || midQ->mid_state != MID_RESPONSE_RECEIVED) {
+		rc = -EIO;
+		cifs_dbg(FYI, "Bad MID state?\n");
+		goto out;
+	}
+
+	buf = (char *)midQ->resp_buf;
+	iov[0].iov_base = buf;
+	iov[0].iov_len = get_rfc1002_length(buf) + 4;
+	if (midQ->large_buf)
+		*resp_buf_type = CIFS_LARGE_BUFFER;
+	else
+		*resp_buf_type = CIFS_SMALL_BUFFER;
+
+	credits = ses->server->ops->get_credits(midQ);
+
+	rc = ses->server->ops->check_receive(midQ, ses->server,
+					     flags & CIFS_LOG_ERROR);
+
+	/* mark it so buf will not be freed by cifs_delete_mid */
+	if ((flags & CIFS_NO_RESP) == 0)
+		midQ->resp_buf = NULL;
+out:
+	cifs_delete_mid(midQ);
+	add_credits(ses->server, credits, optype);
+
+	return rc;
+}
+
+int
+SendReceive(const unsigned int xid, struct cifs_ses *ses,
+	    struct smb_hdr *in_buf, struct smb_hdr *out_buf,
+	    int *pbytes_returned, const int timeout)
+{
+	int rc = 0;
+	struct mid_q_entry *midQ;
+
+	if (ses == NULL) {
+		cifs_dbg(VFS, "Null smb session\n");
+		return -EIO;
+	}
+	if (ses->server == NULL) {
+		cifs_dbg(VFS, "Null tcp session\n");
+		return -EIO;
+	}
+
+	if (ses->server->tcpStatus == CifsExiting)
+		return -ENOENT;
+
+	/* Ensure that we do not send more than 50 overlapping requests
+	   to the same server. We may make this configurable later or
+	   use ses->maxReq */
+
+	if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
+			MAX_CIFS_HDR_SIZE - 4) {
+		cifs_dbg(VFS, "Illegal length, greater than maximum frame, %d\n",
+			 be32_to_cpu(in_buf->smb_buf_length));
+		return -EIO;
+	}
+
+	rc = wait_for_free_request(ses->server, timeout, 0);
+	if (rc)
+		return rc;
+
+	/* make sure that we sign in the same order that we send on this socket
+	   and avoid races inside tcp sendmsg code that could cause corruption
+	   of smb data */
+
+	mutex_lock(&ses->server->srv_mutex);
+
+	rc = allocate_mid(ses, in_buf, &midQ);
+	if (rc) {
+		mutex_unlock(&ses->server->srv_mutex);
+		/* Update # of requests on wire to server */
+		add_credits(ses->server, 1, 0);
+		return rc;
+	}
+
+	rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
+	if (rc) {
+		mutex_unlock(&ses->server->srv_mutex);
+		goto out;
+	}
+
+	midQ->mid_state = MID_REQUEST_SUBMITTED;
+
+	cifs_in_send_inc(ses->server);
+	rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
+	cifs_in_send_dec(ses->server);
+	cifs_save_when_sent(midQ);
+
+	if (rc < 0)
+		ses->server->sequence_number -= 2;
+
+	mutex_unlock(&ses->server->srv_mutex);
+
+	if (rc < 0)
+		goto out;
+
+	if (timeout == CIFS_ASYNC_OP)
+		goto out;
+
+	rc = wait_for_response(ses->server, midQ);
+	if (rc != 0) {
+		send_cancel(ses->server, in_buf, midQ);
+		spin_lock(&GlobalMid_Lock);
+		if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
+			/* no longer considered to be "in-flight" */
+			midQ->callback = DeleteMidQEntry;
+			spin_unlock(&GlobalMid_Lock);
+			add_credits(ses->server, 1, 0);
+			return rc;
+		}
+		spin_unlock(&GlobalMid_Lock);
+	}
+
+	rc = cifs_sync_mid_result(midQ, ses->server);
+	if (rc != 0) {
+		add_credits(ses->server, 1, 0);
+		return rc;
+	}
+
+	if (!midQ->resp_buf || !out_buf ||
+	    midQ->mid_state != MID_RESPONSE_RECEIVED) {
+		rc = -EIO;
+		cifs_dbg(VFS, "Bad MID state?\n");
+		goto out;
+	}
+
+	*pbytes_returned = get_rfc1002_length(midQ->resp_buf);
+	memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
+	rc = cifs_check_receive(midQ, ses->server, 0);
+out:
+	cifs_delete_mid(midQ);
+	add_credits(ses->server, 1, 0);
+
+	return rc;
+}
+
+/* We send a LOCKINGX_CANCEL_LOCK to cause the Windows
+   blocking lock to return. */
+
+static int
+send_lock_cancel(const unsigned int xid, struct cifs_tcon *tcon,
+			struct smb_hdr *in_buf,
+			struct smb_hdr *out_buf)
+{
+	int bytes_returned;
+	struct cifs_ses *ses = tcon->ses;
+	LOCK_REQ *pSMB = (LOCK_REQ *)in_buf;
+
+	/* We just modify the current in_buf to change
+	   the type of lock from LOCKING_ANDX_SHARED_LOCK
+	   or LOCKING_ANDX_EXCLUSIVE_LOCK to
+	   LOCKING_ANDX_CANCEL_LOCK. */
+
+	pSMB->LockType = LOCKING_ANDX_CANCEL_LOCK|LOCKING_ANDX_LARGE_FILES;
+	pSMB->Timeout = 0;
+	pSMB->hdr.Mid = get_next_mid(ses->server);
+
+	return SendReceive(xid, ses, in_buf, out_buf,
+			&bytes_returned, 0);
+}
+
+int
+SendReceiveBlockingLock(const unsigned int xid, struct cifs_tcon *tcon,
+	    struct smb_hdr *in_buf, struct smb_hdr *out_buf,
+	    int *pbytes_returned)
+{
+	int rc = 0;
+	int rstart = 0;
+	struct mid_q_entry *midQ;
+	struct cifs_ses *ses;
+
+	if (tcon == NULL || tcon->ses == NULL) {
+		cifs_dbg(VFS, "Null smb session\n");
+		return -EIO;
+	}
+	ses = tcon->ses;
+
+	if (ses->server == NULL) {
+		cifs_dbg(VFS, "Null tcp session\n");
+		return -EIO;
+	}
+
+	if (ses->server->tcpStatus == CifsExiting)
+		return -ENOENT;
+
+	/* Ensure that we do not send more than 50 overlapping requests
+	   to the same server. We may make this configurable later or
+	   use ses->maxReq */
+
+	if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
+			MAX_CIFS_HDR_SIZE - 4) {
+		cifs_dbg(VFS, "Illegal length, greater than maximum frame, %d\n",
+			 be32_to_cpu(in_buf->smb_buf_length));
+		return -EIO;
+	}
+
+	rc = wait_for_free_request(ses->server, CIFS_BLOCKING_OP, 0);
+	if (rc)
+		return rc;
+
+	/* make sure that we sign in the same order that we send on this socket
+	   and avoid races inside tcp sendmsg code that could cause corruption
+	   of smb data */
+
+	mutex_lock(&ses->server->srv_mutex);
+
+	rc = allocate_mid(ses, in_buf, &midQ);
+	if (rc) {
+		mutex_unlock(&ses->server->srv_mutex);
+		return rc;
+	}
+
+	rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
+	if (rc) {
+		cifs_delete_mid(midQ);
+		mutex_unlock(&ses->server->srv_mutex);
+		return rc;
+	}
+
+	midQ->mid_state = MID_REQUEST_SUBMITTED;
+	cifs_in_send_inc(ses->server);
+	rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
+	cifs_in_send_dec(ses->server);
+	cifs_save_when_sent(midQ);
+
+	if (rc < 0)
+		ses->server->sequence_number -= 2;
+
+	mutex_unlock(&ses->server->srv_mutex);
+
+	if (rc < 0) {
+		cifs_delete_mid(midQ);
+		return rc;
+	}
+
+	/* Wait for a reply - allow signals to interrupt. */
+	rc = wait_event_interruptible(ses->server->response_q,
+		(!(midQ->mid_state == MID_REQUEST_SUBMITTED)) ||
+		((ses->server->tcpStatus != CifsGood) &&
+		 (ses->server->tcpStatus != CifsNew)));
+
+	/* Were we interrupted by a signal ? */
+	if ((rc == -ERESTARTSYS) &&
+		(midQ->mid_state == MID_REQUEST_SUBMITTED) &&
+		((ses->server->tcpStatus == CifsGood) ||
+		 (ses->server->tcpStatus == CifsNew))) {
+
+		if (in_buf->Command == SMB_COM_TRANSACTION2) {
+			/* POSIX lock. We send a NT_CANCEL SMB to cause the
+			   blocking lock to return. */
+			rc = send_cancel(ses->server, in_buf, midQ);
+			if (rc) {
+				cifs_delete_mid(midQ);
+				return rc;
+			}
+		} else {
+			/* Windows lock. We send a LOCKINGX_CANCEL_LOCK
+			   to cause the blocking lock to return. */
+
+			rc = send_lock_cancel(xid, tcon, in_buf, out_buf);
+
+			/* If we get -ENOLCK back the lock may have
+			   already been removed. Don't exit in this case. */
+			if (rc && rc != -ENOLCK) {
+				cifs_delete_mid(midQ);
+				return rc;
+			}
+		}
+
+		rc = wait_for_response(ses->server, midQ);
+		if (rc) {
+			send_cancel(ses->server, in_buf, midQ);
+			spin_lock(&GlobalMid_Lock);
+			if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
+				/* no longer considered to be "in-flight" */
+				midQ->callback = DeleteMidQEntry;
+				spin_unlock(&GlobalMid_Lock);
+				return rc;
+			}
+			spin_unlock(&GlobalMid_Lock);
+		}
+
+		/* We got the response - restart system call. */
+		rstart = 1;
+	}
+
+	rc = cifs_sync_mid_result(midQ, ses->server);
+	if (rc != 0)
+		return rc;
+
+	/* rcvd frame is ok */
+	if (out_buf == NULL || midQ->mid_state != MID_RESPONSE_RECEIVED) {
+		rc = -EIO;
+		cifs_dbg(VFS, "Bad MID state?\n");
+		goto out;
+	}
+
+	*pbytes_returned = get_rfc1002_length(midQ->resp_buf);
+	memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
+	rc = cifs_check_receive(midQ, ses->server, 0);
+out:
+	cifs_delete_mid(midQ);
+	if (rstart && rc == -EACCES)
+		return -ERESTARTSYS;
+	return rc;
+}