linux/fs/cifs/transport.c

/*
 *   fs/cifs/transport.c
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2005
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *
 *   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/wait.h>
#include <linux/net.h>
#include <linux/delay.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"
  
extern mempool_t *cifs_mid_poolp;
extern kmem_cache_t *cifs_oplock_cachep;

static struct mid_q_entry *
AllocMidQEntry(struct smb_hdr *smb_buffer, struct cifsSesInfo *ses)
{
	struct mid_q_entry *temp;

	if (ses == NULL) {
		cERROR(1, ("Null session passed in to AllocMidQEntry"));
		return NULL;
	}
	if (ses->server == NULL) {
		cERROR(1, ("Null TCP session in AllocMidQEntry"));
		return NULL;
	}
	
	temp = (struct mid_q_entry *) mempool_alloc(cifs_mid_poolp,
						    SLAB_KERNEL | SLAB_NOFS);
	if (temp == NULL)
		return temp;
	else {
		memset(temp, 0, sizeof (struct mid_q_entry));
		temp->mid = smb_buffer->Mid;	/* always LE */
		temp->pid = current->pid;
		temp->command = smb_buffer->Command;
		cFYI(1, ("For smb_command %d", temp->command));
	/*	do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */
		/* when mid allocated can be before when sent */
		temp->when_alloc = jiffies;
		temp->ses = ses;
		temp->tsk = current;
	}

	spin_lock(&GlobalMid_Lock);
	list_add_tail(&temp->qhead, &ses->server->pending_mid_q);
	atomic_inc(&midCount);
	temp->midState = MID_REQUEST_ALLOCATED;
	spin_unlock(&GlobalMid_Lock);
	return temp;
}

static void
DeleteMidQEntry(struct mid_q_entry *midEntry)
{
#ifdef CONFIG_CIFS_STATS2
	unsigned long now;
#endif
	spin_lock(&GlobalMid_Lock);
	midEntry->midState = MID_FREE;
	list_del(&midEntry->qhead);
	atomic_dec(&midCount);
	spin_unlock(&GlobalMid_Lock);
	if(midEntry->largeBuf)
		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 != SMB_COM_LOCKING_ANDX)) {
			printk(KERN_DEBUG " CIFS slow rsp: cmd %d mid %d",
			       midEntry->command, midEntry->mid);
			printk(" 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);
}

struct oplock_q_entry *
AllocOplockQEntry(struct inode * pinode, __u16 fid, struct cifsTconInfo * tcon)
{
	struct oplock_q_entry *temp;
	if ((pinode== NULL) || (tcon == NULL)) {
		cERROR(1, ("Null parms passed to AllocOplockQEntry"));
		return NULL;
	}
	temp = (struct oplock_q_entry *) kmem_cache_alloc(cifs_oplock_cachep,
						       SLAB_KERNEL);
	if (temp == NULL)
		return temp;
	else {
		temp->pinode = pinode;
		temp->tcon = tcon;
		temp->netfid = fid;
		spin_lock(&GlobalMid_Lock);
		list_add_tail(&temp->qhead, &GlobalOplock_Q);
		spin_unlock(&GlobalMid_Lock);
	}
	return temp;

}

void DeleteOplockQEntry(struct oplock_q_entry * oplockEntry)
{
	spin_lock(&GlobalMid_Lock); 
    /* should we check if list empty first? */
	list_del(&oplockEntry->qhead);
	spin_unlock(&GlobalMid_Lock);
	kmem_cache_free(cifs_oplock_cachep, oplockEntry);
}

int
smb_send(struct socket *ssocket, struct smb_hdr *smb_buffer,
	 unsigned int smb_buf_length, struct sockaddr *sin)
{
	int rc = 0;
	int i = 0;
	struct msghdr smb_msg;
	struct kvec iov;
	unsigned len = smb_buf_length + 4;

	if(ssocket == NULL)
		return -ENOTSOCK; /* BB eventually add reconnect code here */
	iov.iov_base = smb_buffer;
	iov.iov_len = len;

	smb_msg.msg_name = sin;
	smb_msg.msg_namelen = sizeof (struct sockaddr);
	smb_msg.msg_control = NULL;
	smb_msg.msg_controllen = 0;
	smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL; /* BB add more flags?*/

	/* smb header is converted in header_assemble. bcc and rest of SMB word
	   area, and byte area if necessary, is converted to littleendian in 
	   cifssmb.c and RFC1001 len is converted to bigendian in smb_send 
	   Flags2 is converted in SendReceive */

	smb_buffer->smb_buf_length = cpu_to_be32(smb_buffer->smb_buf_length);
	cFYI(1, ("Sending smb of length %d", smb_buf_length));
	dump_smb(smb_buffer, len);

	while (len > 0) {
		rc = kernel_sendmsg(ssocket, &smb_msg, &iov, 1, len);
		if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
			i++;
		/* smaller timeout here than send2 since smaller size */
		/* Although it may not be required, this also is smaller 
		   oplock break time */  
			if(i > 12) {
				cERROR(1,
				   ("sends on sock %p stuck for 7 seconds",
				    ssocket));
				rc = -EAGAIN;
				break;
			}
			msleep(1 << i);
			continue;
		}
		if (rc < 0) 
			break;
		else
			i = 0; /* reset i after each successful send */
		iov.iov_base += rc;
		iov.iov_len -= rc;
		len -= rc;
	}

	if (rc < 0) {
		cERROR(1,("Error %d sending data on socket to server", rc));
	} else {
		rc = 0;
	}

	return rc;
}

#ifdef CONFIG_CIFS_EXPERIMENTAL
static int
smb_send2(struct socket *ssocket, struct kvec *iov, int n_vec,
	  struct sockaddr *sin)
{
	int rc = 0;
	int i = 0;
	struct msghdr smb_msg;
	struct smb_hdr *smb_buffer = iov[0].iov_base;
	unsigned int len = iov[0].iov_len;
	unsigned int total_len;
	int first_vec = 0;
	
	if(ssocket == NULL)
		return -ENOTSOCK; /* BB eventually add reconnect code here */

	smb_msg.msg_name = sin;
	smb_msg.msg_namelen = sizeof (struct sockaddr);
	smb_msg.msg_control = NULL;
	smb_msg.msg_controllen = 0;
	smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL; /* BB add more flags?*/

	/* smb header is converted in header_assemble. bcc and rest of SMB word
	   area, and byte area if necessary, is converted to littleendian in 
	   cifssmb.c and RFC1001 len is converted to bigendian in smb_send 
	   Flags2 is converted in SendReceive */


	total_len = 0;
	for (i = 0; i < n_vec; i++)
		total_len += iov[i].iov_len;

	smb_buffer->smb_buf_length = cpu_to_be32(smb_buffer->smb_buf_length);
	cFYI(1, ("Sending smb:  total_len %d", total_len));
	dump_smb(smb_buffer, len);

	while (total_len) {
		rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
				    n_vec - first_vec, total_len);
		if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
			i++;
			if(i >= 14) {
				cERROR(1,
				   ("sends on sock %p stuck for 15 seconds",
				    ssocket));
				rc = -EAGAIN;
				break;
			}
			msleep(1 << i);
			continue;
		}
		if (rc < 0) 
			break;

		if (rc >= total_len) {
			WARN_ON(rc > total_len);
			break;
		}
		if(rc == 0) {
			/* should never happen, letting socket clear before
			   retrying is our only obvious option here */
			cERROR(1,("tcp sent no data"));
			msleep(500);
			continue;
		}
		total_len -= 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 */
	}

	if (rc < 0) {
		cERROR(1,("Error %d sending data on socket to server", rc));
	} else
		rc = 0;

	return rc;
}

int
SendReceive2(const unsigned int xid, struct cifsSesInfo *ses, 
	     struct kvec *iov, int n_vec, int *pbytes_returned,
	     const int long_op)
{
	int rc = 0;
	unsigned int receive_len;
	unsigned long timeout;
	struct mid_q_entry *midQ;
	struct smb_hdr *in_buf = iov[0].iov_base;

	if (ses == NULL) {
		cERROR(1,("Null smb session"));
		return -EIO;
	}
	if(ses->server == NULL) {
		cERROR(1,("Null tcp session"));
		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(long_op == -1) {
		/* oplock breaks must not be held up */
		atomic_inc(&ses->server->inFlight);
	} else {
		spin_lock(&GlobalMid_Lock); 
		while(1) {        
			if(atomic_read(&ses->server->inFlight) >= 
					cifs_max_pending){
				spin_unlock(&GlobalMid_Lock);
#ifdef CONFIG_CIFS_STATS2
				atomic_inc(&ses->server->num_waiters);
#endif
				wait_event(ses->server->request_q,
					atomic_read(&ses->server->inFlight)
					 < cifs_max_pending);
#ifdef CONFIG_CIFS_STATS2
				atomic_dec(&ses->server->num_waiters);
#endif
				spin_lock(&GlobalMid_Lock);
			} else {
				if(ses->server->tcpStatus == CifsExiting) {
					spin_unlock(&GlobalMid_Lock);
					return -ENOENT;
				}

			/* can not count locking commands against total since
			   they are allowed to block on server */
					
				if(long_op < 3) {
				/* update # of requests on the wire to server */
					atomic_inc(&ses->server->inFlight);
				}
				spin_unlock(&GlobalMid_Lock);
				break;
			}
		}
	}
	/* 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 */

	down(&ses->server->tcpSem); 

	if (ses->server->tcpStatus == CifsExiting) {
		rc = -ENOENT;
		goto out_unlock2;
	} else if (ses->server->tcpStatus == CifsNeedReconnect) {
		cFYI(1,("tcp session dead - return to caller to retry"));
		rc = -EAGAIN;
		goto out_unlock2;
	} else if (ses->status != CifsGood) {
		/* check if SMB session is bad because we are setting it up */
		if((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) && 
			(in_buf->Command != SMB_COM_NEGOTIATE)) {
			rc = -EAGAIN;
			goto out_unlock2;
		} /* else ok - we are setting up session */
	}
	midQ = AllocMidQEntry(in_buf, ses);
	if (midQ == NULL) {
		up(&ses->server->tcpSem);
		/* If not lock req, update # of requests on wire to server */
		if(long_op < 3) {
			atomic_dec(&ses->server->inFlight); 
			wake_up(&ses->server->request_q);
		}
		return -ENOMEM;
	}

/* BB FIXME */
/* 	rc = cifs_sign_smb2(iov, n_vec, ses->server, &midQ->sequence_number); */

	midQ->midState = MID_REQUEST_SUBMITTED;
#ifdef CONFIG_CIFS_STATS2
	atomic_inc(&ses->server->inSend);
#endif
	rc = smb_send2(ses->server->ssocket, iov, n_vec,
		      (struct sockaddr *) &(ses->server->addr.sockAddr));
#ifdef CONFIG_CIFS_STATS2
	atomic_dec(&ses->server->inSend);
	midQ->when_sent = jiffies;
#endif
	if(rc < 0) {
		DeleteMidQEntry(midQ);
		up(&ses->server->tcpSem);
		/* If not lock req, update # of requests on wire to server */
		if(long_op < 3) {
			atomic_dec(&ses->server->inFlight); 
			wake_up(&ses->server->request_q);
		}
		return rc;
	} else
		up(&ses->server->tcpSem);
	if (long_op == -1)
		goto cifs_no_response_exit2;
	else if (long_op == 2) /* writes past end of file can take loong time */
		timeout = 180 * HZ;
	else if (long_op == 1)
		timeout = 45 * HZ; /* should be greater than 
			servers oplock break timeout (about 43 seconds) */
	else if (long_op > 2) {
		timeout = MAX_SCHEDULE_TIMEOUT;
	} else
		timeout = 15 * HZ;
	/* wait for 15 seconds or until woken up due to response arriving or 
	   due to last connection to this server being unmounted */
	if (signal_pending(current)) {
		/* if signal pending do not hold up user for full smb timeout
		but we still give response a change to complete */
		timeout = 2 * HZ;
	}   

	/* No user interrupts in wait - wreaks havoc with performance */
	if(timeout != MAX_SCHEDULE_TIMEOUT) {
		timeout += jiffies;
		wait_event(ses->server->response_q,
			(!(midQ->midState & MID_REQUEST_SUBMITTED)) || 
			time_after(jiffies, timeout) || 
			((ses->server->tcpStatus != CifsGood) &&
			 (ses->server->tcpStatus != CifsNew)));
	} else {
		wait_event(ses->server->response_q,
			(!(midQ->midState & MID_REQUEST_SUBMITTED)) || 
			((ses->server->tcpStatus != CifsGood) &&
			 (ses->server->tcpStatus != CifsNew)));
	}

	spin_lock(&GlobalMid_Lock);
	if (midQ->resp_buf) {
		spin_unlock(&GlobalMid_Lock);
		receive_len = midQ->resp_buf->smb_buf_length;
	} else {
		cERROR(1,("No response to cmd %d mid %d",
			midQ->command, midQ->mid));
		if(midQ->midState == MID_REQUEST_SUBMITTED) {
			if(ses->server->tcpStatus == CifsExiting)
				rc = -EHOSTDOWN;
			else {
				ses->server->tcpStatus = CifsNeedReconnect;
				midQ->midState = MID_RETRY_NEEDED;
			}
		}

		if (rc != -EHOSTDOWN) {
			if(midQ->midState == MID_RETRY_NEEDED) {
				rc = -EAGAIN;
				cFYI(1,("marking request for retry"));
			} else {
				rc = -EIO;
			}
		}
		spin_unlock(&GlobalMid_Lock);
		DeleteMidQEntry(midQ);
		/* If not lock req, update # of requests on wire to server */
		if(long_op < 3) {
			atomic_dec(&ses->server->inFlight); 
			wake_up(&ses->server->request_q);
		}
		return rc;
	}
  
	if (receive_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) {
		cERROR(1, ("Frame too large received.  Length: %d  Xid: %d",
			receive_len, xid));
		rc = -EIO;
	} else {		/* rcvd frame is ok */

		if (midQ->resp_buf && 
			(midQ->midState == MID_RESPONSE_RECEIVED)) {
			in_buf->smb_buf_length = receive_len;
			/* BB verify that length would not overrun small buf */
			memcpy((char *)in_buf + 4,
			       (char *)midQ->resp_buf + 4,
			       receive_len);

			dump_smb(in_buf, 80);
			/* convert the length into a more usable form */
			if((receive_len > 24) &&
			   (ses->server->secMode & (SECMODE_SIGN_REQUIRED |
					SECMODE_SIGN_ENABLED))) {
				rc = cifs_verify_signature(in_buf,
						ses->server->mac_signing_key,
						midQ->sequence_number+1);
				if(rc) {
					cERROR(1,("Unexpected SMB signature"));
					/* BB FIXME add code to kill session */
				}
			}

			*pbytes_returned = in_buf->smb_buf_length;

			/* BB special case reconnect tid and uid here? */
			/* BB special case Errbadpassword and pwdexpired here */
			rc = map_smb_to_linux_error(in_buf);

			/* convert ByteCount if necessary */
			if (receive_len >=
			    sizeof (struct smb_hdr) -
			    4 /* do not count RFC1001 header */  +
			    (2 * in_buf->WordCount) + 2 /* bcc */ )
				BCC(in_buf) = le16_to_cpu(BCC_LE(in_buf));
		} else {
			rc = -EIO;
			cFYI(1,("Bad MID state?"));
		}
	}
cifs_no_response_exit2:
	DeleteMidQEntry(midQ);

	if(long_op < 3) {
		atomic_dec(&ses->server->inFlight); 
		wake_up(&ses->server->request_q);
	}

	return rc;

out_unlock2:
	up(&ses->server->tcpSem);
	/* If not lock req, update # of requests on wire to server */
	if(long_op < 3) {
		atomic_dec(&ses->server->inFlight); 
		wake_up(&ses->server->request_q);
	}

	return rc;
}
#endif /* CIFS_EXPERIMENTAL */

int
SendReceive(const unsigned int xid, struct cifsSesInfo *ses,
	    struct smb_hdr *in_buf, struct smb_hdr *out_buf,
	    int *pbytes_returned, const int long_op)
{
	int rc = 0;
	unsigned int receive_len;
	unsigned long timeout;
	struct mid_q_entry *midQ;

	if (ses == NULL) {
		cERROR(1,("Null smb session"));
		return -EIO;
	}
	if(ses->server == NULL) {
		cERROR(1,("Null tcp session"));
		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(long_op == -1) {
		/* oplock breaks must not be held up */
		atomic_inc(&ses->server->inFlight);
	} else {
		spin_lock(&GlobalMid_Lock); 
		while(1) {        
			if(atomic_read(&ses->server->inFlight) >= 
					cifs_max_pending){
				spin_unlock(&GlobalMid_Lock);
#ifdef CONFIG_CIFS_STATS2
				atomic_inc(&ses->server->num_waiters);
#endif
				wait_event(ses->server->request_q,
					atomic_read(&ses->server->inFlight)
					 < cifs_max_pending);
#ifdef CONFIG_CIFS_STATS2
				atomic_dec(&ses->server->num_waiters);
#endif
				spin_lock(&GlobalMid_Lock);
			} else {
				if(ses->server->tcpStatus == CifsExiting) {
					spin_unlock(&GlobalMid_Lock);
					return -ENOENT;
				}

			/* can not count locking commands against total since
			   they are allowed to block on server */
					
				if(long_op < 3) {
				/* update # of requests on the wire to server */
					atomic_inc(&ses->server->inFlight);
				}
				spin_unlock(&GlobalMid_Lock);
				break;
			}
		}
	}
	/* 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 */

	down(&ses->server->tcpSem); 

	if (ses->server->tcpStatus == CifsExiting) {
		rc = -ENOENT;
		goto out_unlock;
	} else if (ses->server->tcpStatus == CifsNeedReconnect) {
		cFYI(1,("tcp session dead - return to caller to retry"));
		rc = -EAGAIN;
		goto out_unlock;
	} else if (ses->status != CifsGood) {
		/* check if SMB session is bad because we are setting it up */
		if((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) && 
			(in_buf->Command != SMB_COM_NEGOTIATE)) {
			rc = -EAGAIN;
			goto out_unlock;
		} /* else ok - we are setting up session */
	}
	midQ = AllocMidQEntry(in_buf, ses);
	if (midQ == NULL) {
		up(&ses->server->tcpSem);
		/* If not lock req, update # of requests on wire to server */
		if(long_op < 3) {
			atomic_dec(&ses->server->inFlight); 
			wake_up(&ses->server->request_q);
		}
		return -ENOMEM;
	}

	if (in_buf->smb_buf_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
		up(&ses->server->tcpSem);
		cERROR(1,
		       ("Illegal length, greater than maximum frame, %d ",
			in_buf->smb_buf_length));
		DeleteMidQEntry(midQ);
		/* If not lock req, update # of requests on wire to server */
		if(long_op < 3) {
			atomic_dec(&ses->server->inFlight); 
			wake_up(&ses->server->request_q);
		}
		return -EIO;
	}

	rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);

	midQ->midState = MID_REQUEST_SUBMITTED;
#ifdef CONFIG_CIFS_STATS2
	atomic_inc(&ses->server->inSend);
#endif
	rc = smb_send(ses->server->ssocket, in_buf, in_buf->smb_buf_length,
		      (struct sockaddr *) &(ses->server->addr.sockAddr));
#ifdef CONFIG_CIFS_STATS2
	atomic_dec(&ses->server->inSend);
	midQ->when_sent = jiffies;
#endif
	if(rc < 0) {
		DeleteMidQEntry(midQ);
		up(&ses->server->tcpSem);
		/* If not lock req, update # of requests on wire to server */
		if(long_op < 3) {
			atomic_dec(&ses->server->inFlight); 
			wake_up(&ses->server->request_q);
		}
		return rc;
	} else
		up(&ses->server->tcpSem);
	if (long_op == -1)
		goto cifs_no_response_exit;
	else if (long_op == 2) /* writes past end of file can take loong time */
		timeout = 180 * HZ;
	else if (long_op == 1)
		timeout = 45 * HZ; /* should be greater than 
			servers oplock break timeout (about 43 seconds) */
	else if (long_op > 2) {
		timeout = MAX_SCHEDULE_TIMEOUT;
	} else
		timeout = 15 * HZ;
	/* wait for 15 seconds or until woken up due to response arriving or 
	   due to last connection to this server being unmounted */
	if (signal_pending(current)) {
		/* if signal pending do not hold up user for full smb timeout
		but we still give response a change to complete */
		timeout = 2 * HZ;
	}   

	/* No user interrupts in wait - wreaks havoc with performance */
	if(timeout != MAX_SCHEDULE_TIMEOUT) {
		timeout += jiffies;
		wait_event(ses->server->response_q,
			(!(midQ->midState & MID_REQUEST_SUBMITTED)) || 
			time_after(jiffies, timeout) || 
			((ses->server->tcpStatus != CifsGood) &&
			 (ses->server->tcpStatus != CifsNew)));
	} else {
		wait_event(ses->server->response_q,
			(!(midQ->midState & MID_REQUEST_SUBMITTED)) || 
			((ses->server->tcpStatus != CifsGood) &&
			 (ses->server->tcpStatus != CifsNew)));
	}

	spin_lock(&GlobalMid_Lock);
	if (midQ->resp_buf) {
		spin_unlock(&GlobalMid_Lock);
		receive_len = midQ->resp_buf->smb_buf_length;
	} else {
		cERROR(1,("No response for cmd %d mid %d",
			  midQ->command, midQ->mid));
		if(midQ->midState == MID_REQUEST_SUBMITTED) {
			if(ses->server->tcpStatus == CifsExiting)
				rc = -EHOSTDOWN;
			else {
				ses->server->tcpStatus = CifsNeedReconnect;
				midQ->midState = MID_RETRY_NEEDED;
			}
		}

		if (rc != -EHOSTDOWN) {
			if(midQ->midState == MID_RETRY_NEEDED) {
				rc = -EAGAIN;
				cFYI(1,("marking request for retry"));
			} else {
				rc = -EIO;
			}
		}
		spin_unlock(&GlobalMid_Lock);
		DeleteMidQEntry(midQ);
		/* If not lock req, update # of requests on wire to server */
		if(long_op < 3) {
			atomic_dec(&ses->server->inFlight); 
			wake_up(&ses->server->request_q);
		}
		return rc;
	}
  
	if (receive_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) {
		cERROR(1, ("Frame too large received.  Length: %d  Xid: %d",
			receive_len, xid));
		rc = -EIO;
	} else {		/* rcvd frame is ok */

		if (midQ->resp_buf && out_buf
		    && (midQ->midState == MID_RESPONSE_RECEIVED)) {
			out_buf->smb_buf_length = receive_len;
			memcpy((char *)out_buf + 4,
			       (char *)midQ->resp_buf + 4,
			       receive_len);

			dump_smb(out_buf, 92);
			/* convert the length into a more usable form */
			if((receive_len > 24) &&
			   (ses->server->secMode & (SECMODE_SIGN_REQUIRED |
					SECMODE_SIGN_ENABLED))) {
				rc = cifs_verify_signature(out_buf,
						ses->server->mac_signing_key,
						midQ->sequence_number+1);
				if(rc) {
					cERROR(1,("Unexpected SMB signature"));
					/* BB FIXME add code to kill session */
				}
			}

			*pbytes_returned = out_buf->smb_buf_length;

			/* BB special case reconnect tid and uid here? */
			rc = map_smb_to_linux_error(out_buf);

			/* convert ByteCount if necessary */
			if (receive_len >=
			    sizeof (struct smb_hdr) -
			    4 /* do not count RFC1001 header */  +
			    (2 * out_buf->WordCount) + 2 /* bcc */ )
				BCC(out_buf) = le16_to_cpu(BCC_LE(out_buf));
		} else {
			rc = -EIO;
			cERROR(1,("Bad MID state? "));
		}
	}
cifs_no_response_exit:
	DeleteMidQEntry(midQ);

	if(long_op < 3) {
		atomic_dec(&ses->server->inFlight); 
		wake_up(&ses->server->request_q);
	}

	return rc;

out_unlock:
	up(&ses->server->tcpSem);
	/* If not lock req, update # of requests on wire to server */
	if(long_op < 3) {
		atomic_dec(&ses->server->inFlight); 
		wake_up(&ses->server->request_q);
	}

	return rc;
}