Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1321 insertions, 0 deletions

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
new file mode 100644
index 000000000..59643acb6
--- /dev/null
+++ b/fs/cifs/transport.c
@@ -0,0 +1,1321 @@
+/*
+ *   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/bvec.h>
+#include <linux/highmem.h>
+#include <linux/uaccess.h>
+#include <asm/processor.h>
+#include <linux/mempool.h>
+#include "cifspdu.h"
+#include "cifsglob.h"
+#include "cifsproto.h"
+#include "cifs_debug.h"
+#include "smb2proto.h"
+#include "smbdirect.h"
+
+/* Max number of iovectors we can use off the stack when sending requests. */
+#define CIFS_MAX_IOV_SIZE 8
+
+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);
+	memset(temp, 0, sizeof(struct mid_q_entry));
+	kref_init(&temp->refcount);
+	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;
+}
+
+static void _cifs_mid_q_entry_release(struct kref *refcount)
+{
+	struct mid_q_entry *mid = container_of(refcount, struct mid_q_entry,
+					       refcount);
+
+	mempool_free(mid, cifs_mid_poolp);
+}
+
+void cifs_mid_q_entry_release(struct mid_q_entry *midEntry)
+{
+	spin_lock(&GlobalMid_Lock);
+	kref_put(&midEntry->refcount, _cifs_mid_q_entry_release);
+	spin_unlock(&GlobalMid_Lock);
+}
+
+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 (time_after(now, midEntry->when_alloc + HZ) &&
+	    (midEntry->command != command)) {
+		/* smb2slowcmd[NUMBER_OF_SMB2_COMMANDS] counts by command */
+		if ((le16_to_cpu(midEntry->command) < NUMBER_OF_SMB2_COMMANDS) &&
+		    (le16_to_cpu(midEntry->command) >= 0))
+			cifs_stats_inc(&midEntry->server->smb2slowcmd[le16_to_cpu(midEntry->command)]);
+
+		trace_smb3_slow_rsp(le16_to_cpu(midEntry->command),
+			       midEntry->mid, midEntry->pid,
+			       midEntry->when_sent, midEntry->when_received);
+		if (cifsFYI & CIFS_TIMER) {
+			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
+	cifs_mid_q_entry_release(midEntry);
+}
+
+void
+cifs_delete_mid(struct mid_q_entry *mid)
+{
+	spin_lock(&GlobalMid_Lock);
+	list_del_init(&mid->qhead);
+	mid->mid_flags |= MID_DELETED;
+	spin_unlock(&GlobalMid_Lock);
+
+	DeleteMidQEntry(mid);
+}
+
+/*
+ * smb_send_kvec - send an array of kvecs to the server
+ * @server:	Server to send the data to
+ * @smb_msg:	Message to send
+ * @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 msghdr *smb_msg,
+	      size_t *sent)
+{
+	int rc = 0;
+	int retries = 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;
+
+	while (msg_data_left(smb_msg)) {
+		/*
+		 * 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 = sock_sendmsg(ssocket, smb_msg);
+		if (rc == -EAGAIN) {
+			retries++;
+			if (retries >= 14 ||
+			    (!server->noblocksnd && (retries > 2))) {
+				cifs_dbg(VFS, "sends on sock %p stuck for 15 seconds\n",
+					 ssocket);
+				return -EAGAIN;
+			}
+			msleep(1 << retries);
+			continue;
+		}
+
+		if (rc < 0)
+			return rc;
+
+		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;
+		}
+
+		/* send was at least partially successful */
+		*sent += rc;
+		retries = 0; /* in case we get ENOSPC on the next send */
+	}
+	return 0;
+}
+
+unsigned long
+smb_rqst_len(struct TCP_Server_Info *server, struct smb_rqst *rqst)
+{
+	unsigned int i;
+	struct kvec *iov;
+	int nvec;
+	unsigned long buflen = 0;
+
+	if (server->vals->header_preamble_size == 0 &&
+	    rqst->rq_nvec >= 2 && rqst->rq_iov[0].iov_len == 4) {
+		iov = &rqst->rq_iov[1];
+		nvec = rqst->rq_nvec - 1;
+	} else {
+		iov = rqst->rq_iov;
+		nvec = rqst->rq_nvec;
+	}
+
+	/* total up iov array first */
+	for (i = 0; i < nvec; i++)
+		buflen += iov[i].iov_len;
+
+	/*
+	 * Add in the page array if there is one. The caller needs to make
+	 * sure rq_offset and rq_tailsz are set correctly. If a buffer of
+	 * multiple pages ends at page boundary, rq_tailsz needs to be set to
+	 * PAGE_SIZE.
+	 */
+	if (rqst->rq_npages) {
+		if (rqst->rq_npages == 1)
+			buflen += rqst->rq_tailsz;
+		else {
+			/*
+			 * If there is more than one page, calculate the
+			 * buffer length based on rq_offset and rq_tailsz
+			 */
+			buflen += rqst->rq_pagesz * (rqst->rq_npages - 1) -
+					rqst->rq_offset;
+			buflen += rqst->rq_tailsz;
+		}
+	}
+
+	return buflen;
+}
+
+static int
+__smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
+		struct smb_rqst *rqst)
+{
+	int rc = 0;
+	struct kvec *iov;
+	int n_vec;
+	unsigned int send_length = 0;
+	unsigned int i, j;
+	size_t total_len = 0, sent, size;
+	struct socket *ssocket = server->ssocket;
+	struct msghdr smb_msg;
+	int val = 1;
+	__be32 rfc1002_marker;
+
+	if (cifs_rdma_enabled(server)) {
+		/* return -EAGAIN when connecting or reconnecting */
+		rc = -EAGAIN;
+		if (server->smbd_conn)
+			rc = smbd_send(server, num_rqst, rqst);
+		goto smbd_done;
+	}
+	if (ssocket == NULL)
+		return -ENOTSOCK;
+
+	/* cork the socket */
+	kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
+				(char *)&val, sizeof(val));
+
+	for (j = 0; j < num_rqst; j++)
+		send_length += smb_rqst_len(server, &rqst[j]);
+	rfc1002_marker = cpu_to_be32(send_length);
+
+	/* Generate a rfc1002 marker for SMB2+ */
+	if (server->vals->header_preamble_size == 0) {
+		struct kvec hiov = {
+			.iov_base = &rfc1002_marker,
+			.iov_len  = 4
+		};
+		iov_iter_kvec(&smb_msg.msg_iter, WRITE | ITER_KVEC, &hiov,
+			      1, 4);
+		rc = smb_send_kvec(server, &smb_msg, &sent);
+		if (rc < 0)
+			goto uncork;
+
+		total_len += sent;
+		send_length += 4;
+	}
+
+	cifs_dbg(FYI, "Sending smb: smb_len=%u\n", send_length);
+
+	for (j = 0; j < num_rqst; j++) {
+		iov = rqst[j].rq_iov;
+		n_vec = rqst[j].rq_nvec;
+
+		size = 0;
+		for (i = 0; i < n_vec; i++) {
+			dump_smb(iov[i].iov_base, iov[i].iov_len);
+			size += iov[i].iov_len;
+		}
+
+		iov_iter_kvec(&smb_msg.msg_iter, WRITE | ITER_KVEC,
+			      iov, n_vec, size);
+
+		rc = smb_send_kvec(server, &smb_msg, &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[j].rq_npages; i++) {
+			struct bio_vec bvec;
+
+			bvec.bv_page = rqst[j].rq_pages[i];
+			rqst_page_get_length(&rqst[j], i, &bvec.bv_len,
+					     &bvec.bv_offset);
+
+			iov_iter_bvec(&smb_msg.msg_iter, WRITE | ITER_BVEC,
+				      &bvec, 1, bvec.bv_len);
+			rc = smb_send_kvec(server, &smb_msg, &sent);
+			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 != send_length)) {
+		cifs_dbg(FYI, "partial send (wanted=%u sent=%zu): terminating session\n",
+			 send_length, 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;
+		trace_smb3_partial_send_reconnect(server->CurrentMid,
+						  server->hostname);
+	}
+smbd_done:
+	if (rc < 0 && rc != -EINTR)
+		cifs_dbg(VFS, "Error %d sending data on socket to server\n",
+			 rc);
+	else if (rc > 0)
+		rc = 0;
+
+	return rc;
+}
+
+static int
+smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
+	      struct smb_rqst *rqst, int flags)
+{
+	struct kvec iov;
+	struct smb2_transform_hdr *tr_hdr;
+	struct smb_rqst cur_rqst[MAX_COMPOUND];
+	int rc;
+
+	if (!(flags & CIFS_TRANSFORM_REQ))
+		return __smb_send_rqst(server, num_rqst, rqst);
+
+	if (num_rqst > MAX_COMPOUND - 1)
+		return -ENOMEM;
+
+	if (!server->ops->init_transform_rq) {
+		cifs_dbg(VFS, "Encryption requested but transform callback "
+			 "is missing\n");
+		return -EIO;
+	}
+
+	tr_hdr = kmalloc(sizeof(*tr_hdr), GFP_NOFS);
+	if (!tr_hdr)
+		return -ENOMEM;
+
+	memset(&cur_rqst[0], 0, sizeof(cur_rqst));
+	memset(&iov, 0, sizeof(iov));
+	memset(tr_hdr, 0, sizeof(*tr_hdr));
+
+	iov.iov_base = tr_hdr;
+	iov.iov_len = sizeof(*tr_hdr);
+	cur_rqst[0].rq_iov = &iov;
+	cur_rqst[0].rq_nvec = 1;
+
+	rc = server->ops->init_transform_rq(server, num_rqst + 1,
+					    &cur_rqst[0], rqst);
+	if (rc)
+		goto out;
+
+	rc = __smb_send_rqst(server, num_rqst + 1, &cur_rqst[0]);
+	smb3_free_compound_rqst(num_rqst, &cur_rqst[1]);
+out:
+	kfree(tr_hdr);
+	return rc;
+}
+
+int
+smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
+	 unsigned int smb_buf_length)
+{
+	struct kvec iov[2];
+	struct smb_rqst rqst = { .rq_iov = iov,
+				 .rq_nvec = 2 };
+
+	iov[0].iov_base = smb_buffer;
+	iov[0].iov_len = 4;
+	iov[1].iov_base = (char *)smb_buffer + 4;
+	iov[1].iov_len = smb_buf_length;
+
+	return __smb_send_rqst(server, 1, &rqst);
+}
+
+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;
+
+	if (rqst->rq_iov[0].iov_len != 4 ||
+	    rqst->rq_iov[0].iov_base + 4 != rqst->rq_iov[1].iov_base)
+		return ERR_PTR(-EIO);
+
+	/* 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,
+		mid_handle_t *handle, 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->handle = handle;
+	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);
+
+	/*
+	 * Need to store the time in mid before calling I/O. For call_async,
+	 * I/O response may come back and free the mid entry on another thread.
+	 */
+	cifs_save_when_sent(mid);
+	cifs_in_send_inc(server);
+	rc = smb_send_rqst(server, 1, rqst, flags);
+	cifs_in_send_dec(server);
+
+	if (rc < 0) {
+		revert_current_mid(server, mid->credits);
+		server->sequence_number -= 2;
+		cifs_delete_mid(mid);
+	}
+
+	mutex_unlock(&server->srv_mutex);
+
+	if (rc == 0)
+		return 0;
+
+	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];
+	struct kvec rsp_iov;
+	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, &rsp_iov);
+	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, struct smb_rqst *rqst,
+	    struct mid_q_entry *mid)
+{
+	return server->ops->send_cancel ?
+				server->ops->send_cancel(server, rqst, 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[2];
+		int rc = 0;
+		struct smb_rqst rqst = { .rq_iov = iov,
+					 .rq_nvec = 2 };
+
+		iov[0].iov_base = mid->resp_buf;
+		iov[0].iov_len = 4;
+		iov[1].iov_base = (char *)mid->resp_buf + 4;
+		iov[1].iov_len = len - 4;
+		/* 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;
+
+	if (rqst->rq_iov[0].iov_len != 4 ||
+	    rqst->rq_iov[0].iov_base + 4 != rqst->rq_iov[1].iov_base)
+		return ERR_PTR(-EIO);
+
+	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;
+}
+
+static void
+cifs_noop_callback(struct mid_q_entry *mid)
+{
+}
+
+int
+compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
+		   const int flags, const int num_rqst, struct smb_rqst *rqst,
+		   int *resp_buf_type, struct kvec *resp_iov)
+{
+	int i, j, rc = 0;
+	int timeout, optype;
+	struct mid_q_entry *midQ[MAX_COMPOUND];
+	bool cancelled_mid[MAX_COMPOUND] = {false};
+	unsigned int credits[MAX_COMPOUND] = {0};
+	char *buf;
+
+	timeout = flags & CIFS_TIMEOUT_MASK;
+	optype = flags & CIFS_OP_MASK;
+
+	for (i = 0; i < num_rqst; i++)
+		resp_buf_type[i] = CIFS_NO_BUFFER;  /* no response buf yet */
+
+	if ((ses == NULL) || (ses->server == NULL)) {
+		cifs_dbg(VFS, "Null session\n");
+		return -EIO;
+	}
+
+	if (ses->server->tcpStatus == CifsExiting)
+		return -ENOENT;
+
+	/*
+	 * Ensure we obtain 1 credit per request in the compound chain.
+	 * It can be optimized further by waiting for all the credits
+	 * at once but this can wait long enough if we don't have enough
+	 * credits due to some heavy operations in progress or the server
+	 * not granting us much, so a fallback to the current approach is
+	 * needed anyway.
+	 */
+	for (i = 0; i < num_rqst; i++) {
+		rc = wait_for_free_request(ses->server, timeout, optype);
+		if (rc) {
+			/*
+			 * We haven't sent an SMB packet to the server yet but
+			 * we already obtained credits for i requests in the
+			 * compound chain - need to return those credits back
+			 * for future use. Note that we need to call add_credits
+			 * multiple times to match the way we obtained credits
+			 * in the first place and to account for in flight
+			 * requests correctly.
+			 */
+			for (j = 0; j < i; j++)
+				add_credits(ses->server, 1, optype);
+			return rc;
+		}
+		credits[i] = 1;
+	}
+
+	/*
+	 * 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);
+
+	for (i = 0; i < num_rqst; i++) {
+		midQ[i] = ses->server->ops->setup_request(ses, &rqst[i]);
+		if (IS_ERR(midQ[i])) {
+			revert_current_mid(ses->server, i);
+			for (j = 0; j < i; j++)
+				cifs_delete_mid(midQ[j]);
+			mutex_unlock(&ses->server->srv_mutex);
+
+			/* Update # of requests on wire to server */
+			for (j = 0; j < num_rqst; j++)
+				add_credits(ses->server, credits[j], optype);
+			return PTR_ERR(midQ[i]);
+		}
+
+		midQ[i]->mid_state = MID_REQUEST_SUBMITTED;
+		/*
+		 * We don't invoke the callback compounds unless it is the last
+		 * request.
+		 */
+		if (i < num_rqst - 1)
+			midQ[i]->callback = cifs_noop_callback;
+	}
+	cifs_in_send_inc(ses->server);
+	rc = smb_send_rqst(ses->server, num_rqst, rqst, flags);
+	cifs_in_send_dec(ses->server);
+
+	for (i = 0; i < num_rqst; i++)
+		cifs_save_when_sent(midQ[i]);
+
+	if (rc < 0) {
+		revert_current_mid(ses->server, num_rqst);
+		ses->server->sequence_number -= 2;
+	}
+
+	mutex_unlock(&ses->server->srv_mutex);
+
+	if (rc < 0)
+		goto out;
+
+	/*
+	 * Compounding is never used during session establish.
+	 */
+	if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP)) {
+		mutex_lock(&ses->server->srv_mutex);
+		smb311_update_preauth_hash(ses, rqst[0].rq_iov,
+					   rqst[0].rq_nvec);
+		mutex_unlock(&ses->server->srv_mutex);
+	}
+
+	if (timeout == CIFS_ASYNC_OP)
+		goto out;
+
+	for (i = 0; i < num_rqst; i++) {
+		rc = wait_for_response(ses->server, midQ[i]);
+		if (rc != 0) {
+			cifs_dbg(FYI, "Cancelling wait for mid %llu\n",
+				 midQ[i]->mid);
+			send_cancel(ses->server, &rqst[i], midQ[i]);
+			spin_lock(&GlobalMid_Lock);
+			if (midQ[i]->mid_state == MID_REQUEST_SUBMITTED) {
+				midQ[i]->mid_flags |= MID_WAIT_CANCELLED;
+				midQ[i]->callback = DeleteMidQEntry;
+				cancelled_mid[i] = true;
+			}
+			spin_unlock(&GlobalMid_Lock);
+		}
+	}
+
+	for (i = 0; i < num_rqst; i++)
+		if (!cancelled_mid[i] && midQ[i]->resp_buf
+		    && (midQ[i]->mid_state == MID_RESPONSE_RECEIVED))
+			credits[i] = ses->server->ops->get_credits(midQ[i]);
+
+	for (i = 0; i < num_rqst; i++) {
+		if (rc < 0)
+			goto out;
+
+		rc = cifs_sync_mid_result(midQ[i], ses->server);
+		if (rc != 0) {
+			/* mark this mid as cancelled to not free it below */
+			cancelled_mid[i] = true;
+			goto out;
+		}
+
+		if (!midQ[i]->resp_buf ||
+		    midQ[i]->mid_state != MID_RESPONSE_RECEIVED) {
+			rc = -EIO;
+			cifs_dbg(FYI, "Bad MID state?\n");
+			goto out;
+		}
+
+		buf = (char *)midQ[i]->resp_buf;
+		resp_iov[i].iov_base = buf;
+		resp_iov[i].iov_len = midQ[i]->resp_buf_size +
+			ses->server->vals->header_preamble_size;
+
+		if (midQ[i]->large_buf)
+			resp_buf_type[i] = CIFS_LARGE_BUFFER;
+		else
+			resp_buf_type[i] = CIFS_SMALL_BUFFER;
+
+		rc = ses->server->ops->check_receive(midQ[i], 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[i]->resp_buf = NULL;
+
+	}
+
+	/*
+	 * Compounding is never used during session establish.
+	 */
+	if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP)) {
+		struct kvec iov = {
+			.iov_base = resp_iov[0].iov_base,
+			.iov_len = resp_iov[0].iov_len
+		};
+		mutex_lock(&ses->server->srv_mutex);
+		smb311_update_preauth_hash(ses, &iov, 1);
+		mutex_unlock(&ses->server->srv_mutex);
+	}
+
+out:
+	/*
+	 * This will dequeue all mids. After this it is important that the
+	 * demultiplex_thread will not process any of these mids any futher.
+	 * This is prevented above by using a noop callback that will not
+	 * wake this thread except for the very last PDU.
+	 */
+	for (i = 0; i < num_rqst; i++) {
+		if (!cancelled_mid[i])
+			cifs_delete_mid(midQ[i]);
+		add_credits(ses->server, credits[i], optype);
+	}
+
+	return rc;
+}
+
+int
+cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
+	       struct smb_rqst *rqst, int *resp_buf_type, const int flags,
+	       struct kvec *resp_iov)
+{
+	return compound_send_recv(xid, ses, flags, 1, rqst, resp_buf_type,
+				  resp_iov);
+}
+
+int
+SendReceive2(const unsigned int xid, struct cifs_ses *ses,
+	     struct kvec *iov, int n_vec, int *resp_buf_type /* ret */,
+	     const int flags, struct kvec *resp_iov)
+{
+	struct smb_rqst rqst;
+	struct kvec s_iov[CIFS_MAX_IOV_SIZE], *new_iov;
+	int rc;
+
+	if (n_vec + 1 > CIFS_MAX_IOV_SIZE) {
+		new_iov = kmalloc_array(n_vec + 1, sizeof(struct kvec),
+					GFP_KERNEL);
+		if (!new_iov) {
+			/* otherwise cifs_send_recv below sets resp_buf_type */
+			*resp_buf_type = CIFS_NO_BUFFER;
+			return -ENOMEM;
+		}
+	} else
+		new_iov = s_iov;
+
+	/* 1st iov is a RFC1001 length followed by the rest of the packet */
+	memcpy(new_iov + 1, iov, (sizeof(struct kvec) * n_vec));
+
+	new_iov[0].iov_base = new_iov[1].iov_base;
+	new_iov[0].iov_len = 4;
+	new_iov[1].iov_base += 4;
+	new_iov[1].iov_len -= 4;
+
+	memset(&rqst, 0, sizeof(struct smb_rqst));
+	rqst.rq_iov = new_iov;
+	rqst.rq_nvec = n_vec + 1;
+
+	rc = cifs_send_recv(xid, ses, &rqst, resp_buf_type, flags, resp_iov);
+	if (n_vec + 1 > CIFS_MAX_IOV_SIZE)
+		kfree(new_iov);
+	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;
+	unsigned int len = be32_to_cpu(in_buf->smb_buf_length);
+	struct kvec iov = { .iov_base = in_buf, .iov_len = len };
+	struct smb_rqst rqst = { .rq_iov = &iov, .rq_nvec = 1 };
+
+	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 (len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
+		cifs_dbg(VFS, "Illegal length, greater than maximum frame, %d\n",
+			 len);
+		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, len);
+	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, &rqst, 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;
+	unsigned int len = be32_to_cpu(in_buf->smb_buf_length);
+	struct kvec iov = { .iov_base = in_buf, .iov_len = len };
+	struct smb_rqst rqst = { .rq_iov = &iov, .rq_nvec = 1 };
+
+	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 (len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
+		cifs_dbg(VFS, "Illegal length, greater than maximum frame, %d\n",
+			 len);
+		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, len);
+	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, &rqst, 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, &rqst, 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;
+}