transport.c

Linux内核自带的cifs模块

	up(&ses->server->tcpSem);
	cifs_small_buf_release(in_buf);

	if (rc < 0)
		goto out;

	if (long_op == -1)
		goto out;
	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
		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 chance to complete */
		timeout = 2 * HZ;
	}

	/* No user interrupts in wait - wreaks havoc with performance */
	wait_for_response(ses, midQ, timeout, 10 * HZ);

	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);
		/* Update # of requests on wire to server */
		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)) {

			iov[0].iov_base = (char *)midQ->resp_buf;
			if (midQ->largeBuf)
				*pRespBufType = CIFS_LARGE_BUFFER;
			else
				*pRespBufType = CIFS_SMALL_BUFFER;
			iov[0].iov_len = receive_len + 4;

			dump_smb(midQ->resp_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(midQ->resp_buf,
						&ses->server->mac_signing_key,
						midQ->sequence_number+1);
				if (rc) {
					cERROR(1, ("Unexpected SMB signature"));
					/* BB FIXME add code to kill session */
				}
			}

			/* BB special case reconnect tid and uid here? */
			/* BB special case Errbadpassword and pwdexpired here */
			rc = map_smb_to_linux_error(midQ->resp_buf);

			/* convert ByteCount if necessary */
			if (receive_len >= sizeof(struct smb_hdr) - 4
			    /* do not count RFC1001 header */  +
			    (2 * midQ->resp_buf->WordCount) + 2 /* bcc */ )
				BCC(midQ->resp_buf) =
					le16_to_cpu(BCC_LE(midQ->resp_buf));
			midQ->resp_buf = NULL;  /* mark it so will not be freed
						by DeleteMidQEntry */
		} else {
			rc = -EIO;
			cFYI(1, ("Bad MID state?"));
		}
	}

out:
	DeleteMidQEntry(midQ);
	atomic_dec(&ses->server->inFlight);
	wake_up(&ses->server->request_q);

	return rc;
}

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 */

	rc = wait_for_free_request(ses, long_op);
	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 */

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

	rc = allocate_mid(ses, in_buf, &midQ);
	if (rc) {
		up(&ses->server->tcpSem);
		/* Update # of requests on wire to server */
		atomic_dec(&ses->server->inFlight);
		wake_up(&ses->server->request_q);
		return rc;
	}

	if (in_buf->smb_buf_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
		cERROR(1, ("Illegal length, greater than maximum frame, %d",
			in_buf->smb_buf_length));
		DeleteMidQEntry(midQ);
		up(&ses->server->tcpSem);
		/* Update # of requests on wire to server */
		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
	up(&ses->server->tcpSem);

	if (rc < 0)
		goto out;

	if (long_op == -1)
		goto out;
	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
		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 chance to complete */
		timeout = 2 * HZ;
	}

	/* No user interrupts in wait - wreaks havoc with performance */
	wait_for_response(ses, midQ, timeout, 10 * HZ);

	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);
		/* Update # of requests on wire to server */
		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?"));
		}
	}

out:
	DeleteMidQEntry(midQ);
	atomic_dec(&ses->server->inFlight);
	wake_up(&ses->server->request_q);

	return rc;
}

/* Send an NT_CANCEL SMB to cause the POSIX blocking lock to return. */

static int
send_nt_cancel(struct cifsTconInfo *tcon, struct smb_hdr *in_buf,
		struct mid_q_entry *midQ)
{
	int rc = 0;
	struct cifsSesInfo *ses = tcon->ses;
	__u16 mid = in_buf->Mid;

	header_assemble(in_buf, SMB_COM_NT_CANCEL, tcon, 0);
	in_buf->Mid = mid;
	down(&ses->server->tcpSem);
	rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
	if (rc) {
		up(&ses->server->tcpSem);
		return rc;
	}
	rc = smb_send(ses->server->ssocket, in_buf, in_buf->smb_buf_length,
	      (struct sockaddr *) &(ses->server->addr.sockAddr));
	up(&ses->server->tcpSem);
	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 cifsTconInfo *tcon,
			struct smb_hdr *in_buf,
			struct smb_hdr *out_buf)
{
	int bytes_returned;
	struct cifsSesInfo *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 = GetNextMid(ses->server);

	return SendReceive(xid, ses, in_buf, out_buf,
			&bytes_returned, 0);
}

int
SendReceiveBlockingLock(const unsigned int xid, struct cifsTconInfo *tcon,
	    struct smb_hdr *in_buf, struct smb_hdr *out_buf,
	    int *pbytes_returned)
{
	int rc = 0;
	int rstart = 0;
	unsigned int receive_len;
	struct mid_q_entry *midQ;
	struct cifsSesInfo *ses;

	if (tcon == NULL || tcon->ses == NULL) {
		cERROR(1, ("Null smb session"));
		return -EIO;
	}
	ses = tcon->ses;

	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 */

	rc = wait_for_free_request(ses, 3);
	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 */

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

	rc = allocate_mid(ses, in_buf, &midQ);
	if (rc) {
		up(&ses->server->tcpSem);
		return rc;
	}

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

	if (rc < 0) {
		DeleteMidQEntry(midQ);
		return rc;
	}

	/* Wait for a reply - allow signals to interrupt. */
	rc = wait_event_interruptible(ses->server->response_q,
		(!(midQ->midState == MID_REQUEST_SUBMITTED)) ||
		((ses->server->tcpStatus != CifsGood) &&
		 (ses->server->tcpStatus != CifsNew)));

	/* Were we interrupted by a signal ? */
	if ((rc == -ERESTARTSYS) &&
		(midQ->midState == 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_nt_cancel(tcon, in_buf, midQ);
			if (rc) {
				DeleteMidQEntry(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) {
				DeleteMidQEntry(midQ);
				return rc;
			}
		}

		/* Wait 5 seconds for the response. */
		if (wait_for_response(ses, midQ, 5 * HZ, 5 * HZ) == 0) {
			/* We got the response - restart system call. */
			rstart = 1;
		}
	}

	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);
		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?"));
		}
	}
	DeleteMidQEntry(midQ);
	if (rstart && rc == -EACCES)
		return -ERESTARTSYS;
	return rc;
}