fs/cifs/transport.c

   1 /*
   2  *   fs/cifs/transport.c
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2002,2008
   5  *   Author(s): Steve French (sfrench@us.ibm.com)
   6  *   Jeremy Allison (jra@samba.org) 2006.
   7  *
   8  *   This library is free software; you can redistribute it and/or modify
   9  *   it under the terms of the GNU Lesser General Public License as published
  10  *   by the Free Software Foundation; either version 2.1 of the License, or
  11  *   (at your option) any later version.
  12  *
  13  *   This library is distributed in the hope that it will be useful,
  14  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  16  *   the GNU Lesser General Public License for more details.
  17  *
  18  *   You should have received a copy of the GNU Lesser General Public License
  19  *   along with this library; if not, write to the Free Software
  20  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21  */
  22
  23 #include <linux/fs.h>
  24 #include <linux/list.h>
  25 #include <linux/gfp.h>
  26 #include <linux/wait.h>
  27 #include <linux/net.h>
  28 #include <linux/delay.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/processor.h>
  31 #include <linux/mempool.h>
  32 #include "cifspdu.h"
  33 #include "cifsglob.h"
  34 #include "cifsproto.h"
  35 #include "cifs_debug.h"
  36
  37 extern mempool_t *cifs_mid_poolp;
  38
  39 static void
  40 wake_up_task(struct mid_q_entry *mid)
  41 {
  42         wake_up_process(mid->callback_data);
  43 }
  44
  45 struct mid_q_entry *
  46 AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
  47 {
  48         struct mid_q_entry *temp;
  49
  50         if (server == NULL) {
  51                 cERROR(1, "Null TCP session in AllocMidQEntry");
  52                 return NULL;
  53         }
  54
  55         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
  56         if (temp == NULL)
  57                 return temp;
  58         else {
  59                 memset(temp, 0, sizeof(struct mid_q_entry));
  60                 temp->mid = smb_buffer->Mid;    /* always LE */
  61                 temp->pid = current->pid;
  62                 temp->command = smb_buffer->Command;
  63                 cFYI(1, "For smb_command %d", temp->command);
  64         /*      do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */
  65                 /* when mid allocated can be before when sent */
  66                 temp->when_alloc = jiffies;
  67
  68                 /*
  69                  * The default is for the mid to be synchronous, so the
  70                  * default callback just wakes up the current task.
  71                  */
  72                 temp->callback = wake_up_task;
  73                 temp->callback_data = current;
  74         }
  75
  76         atomic_inc(&midCount);
  77         temp->midState = MID_REQUEST_ALLOCATED;
  78         return temp;
  79 }
  80
  81 void
  82 DeleteMidQEntry(struct mid_q_entry *midEntry)
  83 {
  84 #ifdef CONFIG_CIFS_STATS2
  85         unsigned long now;
  86 #endif
  87         midEntry->midState = MID_FREE;
  88         atomic_dec(&midCount);
  89         if (midEntry->largeBuf)
  90                 cifs_buf_release(midEntry->resp_buf);
  91         else
  92                 cifs_small_buf_release(midEntry->resp_buf);
  93 #ifdef CONFIG_CIFS_STATS2
  94         now = jiffies;
  95         /* commands taking longer than one second are indications that
  96            something is wrong, unless it is quite a slow link or server */
  97         if ((now - midEntry->when_alloc) > HZ) {
  98                 if ((cifsFYI & CIFS_TIMER) &&
  99                    (midEntry->command != SMB_COM_LOCKING_ANDX)) {
 100                         printk(KERN_DEBUG " CIFS slow rsp: cmd %d mid %d",
 101                                midEntry->command, midEntry->mid);
 102                         printk(" A: 0x%lx S: 0x%lx R: 0x%lx\n",
 103                                now - midEntry->when_alloc,
 104                                now - midEntry->when_sent,
 105                                now - midEntry->when_received);
 106                 }
 107         }
 108 #endif
 109         mempool_free(midEntry, cifs_mid_poolp);
 110 }
 111
 112 static void
 113 delete_mid(struct mid_q_entry *mid)
 114 {
 115         spin_lock(&GlobalMid_Lock);
 116         list_del(&mid->qhead);
 117         spin_unlock(&GlobalMid_Lock);
 118
 119         DeleteMidQEntry(mid);
 120 }
 121
 122 static int
 123 smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
 124 {
 125         int rc = 0;
 126         int i = 0;
 127         struct msghdr smb_msg;
 128         struct smb_hdr *smb_buffer = iov[0].iov_base;
 129         unsigned int len = iov[0].iov_len;
 130         unsigned int total_len;
 131         int first_vec = 0;
 132         unsigned int smb_buf_length = smb_buffer->smb_buf_length;
 133         struct socket *ssocket = server->ssocket;
 134
 135         if (ssocket == NULL)
 136                 return -ENOTSOCK; /* BB eventually add reconnect code here */
 137
 138         smb_msg.msg_name = (struct sockaddr *) &server->dstaddr;
 139         smb_msg.msg_namelen = sizeof(struct sockaddr);
 140         smb_msg.msg_control = NULL;
 141         smb_msg.msg_controllen = 0;
 142         if (server->noblocksnd)
 143                 smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL;
 144         else
 145                 smb_msg.msg_flags = MSG_NOSIGNAL;
 146
 147         /* smb header is converted in header_assemble. bcc and rest of SMB word
 148            area, and byte area if necessary, is converted to littleendian in
 149            cifssmb.c and RFC1001 len is converted to bigendian in smb_send
 150            Flags2 is converted in SendReceive */
 151
 152
 153         total_len = 0;
 154         for (i = 0; i < n_vec; i++)
 155                 total_len += iov[i].iov_len;
 156
 157         smb_buffer->smb_buf_length = cpu_to_be32(smb_buffer->smb_buf_length);
 158         cFYI(1, "Sending smb:  total_len %d", total_len);
 159         dump_smb(smb_buffer, len);
 160
 161         i = 0;
 162         while (total_len) {
 163                 rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
 164                                     n_vec - first_vec, total_len);
 165                 if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
 166                         i++;
 167                         /* if blocking send we try 3 times, since each can block
 168                            for 5 seconds. For nonblocking  we have to try more
 169                            but wait increasing amounts of time allowing time for
 170                            socket to clear.  The overall time we wait in either
 171                            case to send on the socket is about 15 seconds.
 172                            Similarly we wait for 15 seconds for
 173                            a response from the server in SendReceive[2]
 174                            for the server to send a response back for
 175                            most types of requests (except SMB Write
 176                            past end of file which can be slow, and
 177                            blocking lock operations). NFS waits slightly longer
 178                            than CIFS, but this can make it take longer for
 179                            nonresponsive servers to be detected and 15 seconds
 180                            is more than enough time for modern networks to
 181                            send a packet.  In most cases if we fail to send
 182                            after the retries we will kill the socket and
 183                            reconnect which may clear the network problem.
 184                         */
 185                         if ((i >= 14) || (!server->noblocksnd && (i > 2))) {
 186                                 cERROR(1, "sends on sock %p stuck for 15 seconds",
 187                                     ssocket);
 188                                 rc = -EAGAIN;
 189                                 break;
 190                         }
 191                         msleep(1 << i);
 192                         continue;
 193                 }
 194                 if (rc < 0)
 195                         break;
 196
 197                 if (rc == total_len) {
 198                         total_len = 0;
 199                         break;
 200                 } else if (rc > total_len) {
 201                         cERROR(1, "sent %d requested %d", rc, total_len);
 202                         break;
 203                 }
 204                 if (rc == 0) {
 205                         /* should never happen, letting socket clear before
 206                            retrying is our only obvious option here */
 207                         cERROR(1, "tcp sent no data");
 208                         msleep(500);
 209                         continue;
 210                 }
 211                 total_len -= rc;
 212                 /* the line below resets i */
 213                 for (i = first_vec; i < n_vec; i++) {
 214                         if (iov[i].iov_len) {
 215                                 if (rc > iov[i].iov_len) {
 216                                         rc -= iov[i].iov_len;
 217                                         iov[i].iov_len = 0;
 218                                 } else {
 219                                         iov[i].iov_base += rc;
 220                                         iov[i].iov_len -= rc;
 221                                         first_vec = i;
 222                                         break;
 223                                 }
 224                         }
 225                 }
 226                 i = 0; /* in case we get ENOSPC on the next send */
 227         }
 228
 229         if ((total_len > 0) && (total_len != smb_buf_length + 4)) {
 230                 cFYI(1, "partial send (%d remaining), terminating session",
 231                         total_len);
 232                 /* If we have only sent part of an SMB then the next SMB
 233                    could be taken as the remainder of this one.  We need
 234                    to kill the socket so the server throws away the partial
 235                    SMB */
 236                 server->tcpStatus = CifsNeedReconnect;
 237         }
 238
 239         if (rc < 0) {
 240                 cERROR(1, "Error %d sending data on socket to server", rc);
 241         } else
 242                 rc = 0;
 243
 244         /* Don't want to modify the buffer as a
 245            side effect of this call. */
 246         smb_buffer->smb_buf_length = smb_buf_length;
 247
 248         return rc;
 249 }
 250
 251 int
 252 smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
 253          unsigned int smb_buf_length)
 254 {
 255         struct kvec iov;
 256
 257         iov.iov_base = smb_buffer;
 258         iov.iov_len = smb_buf_length + 4;
 259
 260         return smb_sendv(server, &iov, 1);
 261 }
 262
 263 static int wait_for_free_request(struct TCP_Server_Info *server,
 264                                  const int long_op)
 265 {
 266         if (long_op == CIFS_ASYNC_OP) {
 267                 /* oplock breaks must not be held up */
 268                 atomic_inc(&server->inFlight);
 269                 return 0;
 270         }
 271
 272         spin_lock(&GlobalMid_Lock);
 273         while (1) {
 274                 if (atomic_read(&server->inFlight) >= cifs_max_pending) {
 275                         spin_unlock(&GlobalMid_Lock);
 276 #ifdef CONFIG_CIFS_STATS2
 277                         atomic_inc(&server->num_waiters);
 278 #endif
 279                         wait_event(server->request_q,
 280                                    atomic_read(&server->inFlight)
 281                                      < cifs_max_pending);
 282 #ifdef CONFIG_CIFS_STATS2
 283                         atomic_dec(&server->num_waiters);
 284 #endif
 285                         spin_lock(&GlobalMid_Lock);
 286                 } else {
 287                         if (server->tcpStatus == CifsExiting) {
 288                                 spin_unlock(&GlobalMid_Lock);
 289                                 return -ENOENT;
 290                         }
 291
 292                         /* can not count locking commands against total
 293                            as they are allowed to block on server */
 294
 295                         /* update # of requests on the wire to server */
 296                         if (long_op != CIFS_BLOCKING_OP)
 297                                 atomic_inc(&server->inFlight);
 298                         spin_unlock(&GlobalMid_Lock);
 299                         break;
 300                 }
 301         }
 302         return 0;
 303 }
 304
 305 static int allocate_mid(struct cifsSesInfo *ses, struct smb_hdr *in_buf,
 306                         struct mid_q_entry **ppmidQ)
 307 {
 308         if (ses->server->tcpStatus == CifsExiting) {
 309                 return -ENOENT;
 310         }
 311
 312         if (ses->server->tcpStatus == CifsNeedReconnect) {
 313                 cFYI(1, "tcp session dead - return to caller to retry");
 314                 return -EAGAIN;
 315         }
 316
 317         if (ses->status != CifsGood) {
 318                 /* check if SMB session is bad because we are setting it up */
 319                 if ((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
 320                         (in_buf->Command != SMB_COM_NEGOTIATE))
 321                         return -EAGAIN;
 322                 /* else ok - we are setting up session */
 323         }
 324         *ppmidQ = AllocMidQEntry(in_buf, ses->server);
 325         if (*ppmidQ == NULL)
 326                 return -ENOMEM;
 327         spin_lock(&GlobalMid_Lock);
 328         list_add_tail(&(*ppmidQ)->qhead, &ses->server->pending_mid_q);
 329         spin_unlock(&GlobalMid_Lock);
 330         return 0;
 331 }
 332
 333 static int
 334 wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
 335 {
 336         int error;
 337
 338         error = wait_event_killable(server->response_q,
 339                                     midQ->midState != MID_REQUEST_SUBMITTED);
 340         if (error < 0)
 341                 return -ERESTARTSYS;
 342
 343         return 0;
 344 }
 345
 346
 347 /*
 348  * Send a SMB request and set the callback function in the mid to handle
 349  * the result. Caller is responsible for dealing with timeouts.
 350  */
 351 int
 352 cifs_call_async(struct TCP_Server_Info *server, struct smb_hdr *in_buf,
 353                 mid_callback_t *callback, void *cbdata)
 354 {
 355         int rc;
 356         struct mid_q_entry *mid;
 357
 358         rc = wait_for_free_request(server, CIFS_ASYNC_OP);
 359         if (rc)
 360                 return rc;
 361
 362         mutex_lock(&server->srv_mutex);
 363         mid = AllocMidQEntry(in_buf, server);
 364         if (mid == NULL) {
 365                 mutex_unlock(&server->srv_mutex);
 366                 return -ENOMEM;
 367         }
 368
 369         /* put it on the pending_mid_q */
 370         spin_lock(&GlobalMid_Lock);
 371         list_add_tail(&mid->qhead, &server->pending_mid_q);
 372         spin_unlock(&GlobalMid_Lock);
 373
 374         rc = cifs_sign_smb(in_buf, server, &mid->sequence_number);
 375         if (rc) {
 376                 mutex_unlock(&server->srv_mutex);
 377                 goto out_err;
 378         }
 379
 380         mid->callback = callback;
 381         mid->callback_data = cbdata;
 382         mid->midState = MID_REQUEST_SUBMITTED;
 383 #ifdef CONFIG_CIFS_STATS2
 384         atomic_inc(&server->inSend);
 385 #endif
 386         rc = smb_send(server, in_buf, in_buf->smb_buf_length);
 387 #ifdef CONFIG_CIFS_STATS2
 388         atomic_dec(&server->inSend);
 389         mid->when_sent = jiffies;
 390 #endif
 391         mutex_unlock(&server->srv_mutex);
 392         if (rc)
 393                 goto out_err;
 394
 395         return rc;
 396 out_err:
 397         delete_mid(mid);
 398         atomic_dec(&server->inFlight);
 399         wake_up(&server->request_q);
 400         return rc;
 401 }
 402
 403 /*
 404  *
 405  * Send an SMB Request.  No response info (other than return code)
 406  * needs to be parsed.
 407  *
 408  * flags indicate the type of request buffer and how long to wait
 409  * and whether to log NT STATUS code (error) before mapping it to POSIX error
 410  *
 411  */
 412 int
 413 SendReceiveNoRsp(const unsigned int xid, struct cifsSesInfo *ses,
 414                 struct smb_hdr *in_buf, int flags)
 415 {
 416         int rc;
 417         struct kvec iov[1];
 418         int resp_buf_type;
 419
 420         iov[0].iov_base = (char *)in_buf;
 421         iov[0].iov_len = in_buf->smb_buf_length + 4;
 422         flags |= CIFS_NO_RESP;
 423         rc = SendReceive2(xid, ses, iov, 1, &resp_buf_type, flags);
 424         cFYI(DBG2, "SendRcvNoRsp flags %d rc %d", flags, rc);
 425
 426         return rc;
 427 }
 428
 429 static int
 430 sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
 431 {
 432         int rc = 0;
 433
 434         cFYI(1, "%s: cmd=%d mid=%d state=%d", __func__, mid->command,
 435                 mid->mid, mid->midState);
 436
 437         spin_lock(&GlobalMid_Lock);
 438         /* ensure that it's no longer on the pending_mid_q */
 439         list_del_init(&mid->qhead);
 440
 441         switch (mid->midState) {
 442         case MID_RESPONSE_RECEIVED:
 443                 spin_unlock(&GlobalMid_Lock);
 444                 return rc;
 445         case MID_REQUEST_SUBMITTED:
 446                 /* socket is going down, reject all calls */
 447                 if (server->tcpStatus == CifsExiting) {
 448                         cERROR(1, "%s: canceling mid=%d cmd=0x%x state=%d",
 449                                __func__, mid->mid, mid->command, mid->midState);
 450                         rc = -EHOSTDOWN;
 451                         break;
 452                 }
 453         case MID_RETRY_NEEDED:
 454                 rc = -EAGAIN;
 455                 break;
 456         default:
 457                 cERROR(1, "%s: invalid mid state mid=%d state=%d", __func__,
 458                         mid->mid, mid->midState);
 459                 rc = -EIO;
 460         }
 461         spin_unlock(&GlobalMid_Lock);
 462
 463         DeleteMidQEntry(mid);
 464         return rc;
 465 }
 466
 467 /*
 468  * An NT cancel request header looks just like the original request except:
 469  *
 470  * The Command is SMB_COM_NT_CANCEL
 471  * The WordCount is zeroed out
 472  * The ByteCount is zeroed out
 473  *
 474  * This function mangles an existing request buffer into a
 475  * SMB_COM_NT_CANCEL request and then sends it.
 476  */
 477 static int
 478 send_nt_cancel(struct TCP_Server_Info *server, struct smb_hdr *in_buf,
 479                 struct mid_q_entry *mid)
 480 {
 481         int rc = 0;
 482
 483         /* -4 for RFC1001 length and +2 for BCC field */
 484         in_buf->smb_buf_length = sizeof(struct smb_hdr) - 4  + 2;
 485         in_buf->Command = SMB_COM_NT_CANCEL;
 486         in_buf->WordCount = 0;
 487         put_bcc_le(0, in_buf);
 488
 489         mutex_lock(&server->srv_mutex);
 490         rc = cifs_sign_smb(in_buf, server, &mid->sequence_number);
 491         if (rc) {
 492                 mutex_unlock(&server->srv_mutex);
 493                 return rc;
 494         }
 495         rc = smb_send(server, in_buf, in_buf->smb_buf_length);
 496         mutex_unlock(&server->srv_mutex);
 497
 498         cFYI(1, "issued NT_CANCEL for mid %u, rc = %d",
 499                 in_buf->Mid, rc);
 500
 501         return rc;
 502 }
 503
 504 int
 505 SendReceive2(const unsigned int xid, struct cifsSesInfo *ses,
 506              struct kvec *iov, int n_vec, int *pRespBufType /* ret */,
 507              const int flags)
 508 {
 509         int rc = 0;
 510         int long_op;
 511         unsigned int receive_len;
 512         struct mid_q_entry *midQ;
 513         struct smb_hdr *in_buf = iov[0].iov_base;
 514
 515         long_op = flags & CIFS_TIMEOUT_MASK;
 516
 517         *pRespBufType = CIFS_NO_BUFFER;  /* no response buf yet */
 518
 519         if ((ses == NULL) || (ses->server == NULL)) {
 520                 cifs_small_buf_release(in_buf);
 521                 cERROR(1, "Null session");
 522                 return -EIO;
 523         }
 524
 525         if (ses->server->tcpStatus == CifsExiting) {
 526                 cifs_small_buf_release(in_buf);
 527                 return -ENOENT;
 528         }
 529
 530         /* Ensure that we do not send more than 50 overlapping requests
 531            to the same server. We may make this configurable later or
 532            use ses->maxReq */
 533
 534         rc = wait_for_free_request(ses->server, long_op);
 535         if (rc) {
 536                 cifs_small_buf_release(in_buf);
 537                 return rc;
 538         }
 539
 540         /* make sure that we sign in the same order that we send on this socket
 541            and avoid races inside tcp sendmsg code that could cause corruption
 542            of smb data */
 543
 544         mutex_lock(&ses->server->srv_mutex);
 545
 546         rc = allocate_mid(ses, in_buf, &midQ);
 547         if (rc) {
 548                 mutex_unlock(&ses->server->srv_mutex);
 549                 cifs_small_buf_release(in_buf);
 550                 /* Update # of requests on wire to server */
 551                 atomic_dec(&ses->server->inFlight);
 552                 wake_up(&ses->server->request_q);
 553                 return rc;
 554         }
 555         rc = cifs_sign_smb2(iov, n_vec, ses->server, &midQ->sequence_number);
 556         if (rc) {
 557                 mutex_unlock(&ses->server->srv_mutex);
 558                 cifs_small_buf_release(in_buf);
 559                 goto out;
 560         }
 561
 562         midQ->midState = MID_REQUEST_SUBMITTED;
 563 #ifdef CONFIG_CIFS_STATS2
 564         atomic_inc(&ses->server->inSend);
 565 #endif
 566         rc = smb_sendv(ses->server, iov, n_vec);
 567 #ifdef CONFIG_CIFS_STATS2
 568         atomic_dec(&ses->server->inSend);
 569         midQ->when_sent = jiffies;
 570 #endif
 571
 572         mutex_unlock(&ses->server->srv_mutex);
 573         cifs_small_buf_release(in_buf);
 574
 575         if (rc < 0)
 576                 goto out;
 577
 578         if (long_op == CIFS_ASYNC_OP)
 579                 goto out;
 580
 581         rc = wait_for_response(ses->server, midQ);
 582         if (rc != 0) {
 583                 spin_lock(&GlobalMid_Lock);
 584                 if (midQ->midState == MID_REQUEST_SUBMITTED) {
 585                         midQ->callback = DeleteMidQEntry;
 586                         spin_unlock(&GlobalMid_Lock);
 587                         atomic_dec(&ses->server->inFlight);
 588                         wake_up(&ses->server->request_q);
 589                         return rc;
 590                 }
 591                 spin_unlock(&GlobalMid_Lock);
 592         }
 593
 594         rc = sync_mid_result(midQ, ses->server);
 595         if (rc != 0) {
 596                 atomic_dec(&ses->server->inFlight);
 597                 wake_up(&ses->server->request_q);
 598                 return rc;
 599         }
 600
 601         receive_len = midQ->resp_buf->smb_buf_length;
 602
 603         if (receive_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) {
 604                 cERROR(1, "Frame too large received.  Length: %d  Xid: %d",
 605                         receive_len, xid);
 606                 rc = -EIO;
 607                 goto out;
 608         }
 609
 610         /* rcvd frame is ok */
 611
 612         if (midQ->resp_buf &&
 613             (midQ->midState == MID_RESPONSE_RECEIVED)) {
 614
 615                 iov[0].iov_base = (char *)midQ->resp_buf;
 616                 if (midQ->largeBuf)
 617                         *pRespBufType = CIFS_LARGE_BUFFER;
 618                 else
 619                         *pRespBufType = CIFS_SMALL_BUFFER;
 620                 iov[0].iov_len = receive_len + 4;
 621
 622                 dump_smb(midQ->resp_buf, 80);
 623                 /* convert the length into a more usable form */
 624                 if ((receive_len > 24) &&
 625                     (ses->server->secMode & (SECMODE_SIGN_REQUIRED |
 626                                              SECMODE_SIGN_ENABLED))) {
 627                         rc = cifs_verify_signature(midQ->resp_buf,
 628                                                 ses->server,
 629                                                 midQ->sequence_number+1);
 630                         if (rc) {
 631                                 cERROR(1, "Unexpected SMB signature");
 632                                 /* BB FIXME add code to kill session */
 633                         }
 634                 }
 635
 636                 /* BB special case reconnect tid and uid here? */
 637                 rc = map_smb_to_linux_error(midQ->resp_buf,
 638                                             flags & CIFS_LOG_ERROR);
 639
 640                 /* convert ByteCount if necessary */
 641                 if (receive_len >= sizeof(struct smb_hdr) - 4
 642                     /* do not count RFC1001 header */  +
 643                     (2 * midQ->resp_buf->WordCount) + 2 /* bcc */ )
 644                         put_bcc(get_bcc_le(midQ->resp_buf), midQ->resp_buf);
 645                 if ((flags & CIFS_NO_RESP) == 0)
 646                         midQ->resp_buf = NULL;  /* mark it so buf will
 647                                                    not be freed by
 648                                                    delete_mid */
 649         } else {
 650                 rc = -EIO;
 651                 cFYI(1, "Bad MID state?");
 652         }
 653
 654 out:
 655         delete_mid(midQ);
 656         atomic_dec(&ses->server->inFlight);
 657         wake_up(&ses->server->request_q);
 658
 659         return rc;
 660 }
 661
 662 int
 663 SendReceive(const unsigned int xid, struct cifsSesInfo *ses,
 664             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
 665             int *pbytes_returned, const int long_op)
 666 {
 667         int rc = 0;
 668         unsigned int receive_len;
 669         struct mid_q_entry *midQ;
 670
 671         if (ses == NULL) {
 672                 cERROR(1, "Null smb session");
 673                 return -EIO;
 674         }
 675         if (ses->server == NULL) {
 676                 cERROR(1, "Null tcp session");
 677                 return -EIO;
 678         }
 679
 680         if (ses->server->tcpStatus == CifsExiting)
 681                 return -ENOENT;
 682
 683         /* Ensure that we do not send more than 50 overlapping requests
 684            to the same server. We may make this configurable later or
 685            use ses->maxReq */
 686
 687         if (in_buf->smb_buf_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
 688                 cERROR(1, "Illegal length, greater than maximum frame, %d",
 689                            in_buf->smb_buf_length);
 690                 return -EIO;
 691         }
 692
 693         rc = wait_for_free_request(ses->server, long_op);
 694         if (rc)
 695                 return rc;
 696
 697         /* make sure that we sign in the same order that we send on this socket
 698            and avoid races inside tcp sendmsg code that could cause corruption
 699            of smb data */
 700
 701         mutex_lock(&ses->server->srv_mutex);
 702
 703         rc = allocate_mid(ses, in_buf, &midQ);
 704         if (rc) {
 705                 mutex_unlock(&ses->server->srv_mutex);
 706                 /* Update # of requests on wire to server */
 707                 atomic_dec(&ses->server->inFlight);
 708                 wake_up(&ses->server->request_q);
 709                 return rc;
 710         }
 711
 712         rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
 713         if (rc) {
 714                 mutex_unlock(&ses->server->srv_mutex);
 715                 goto out;
 716         }
 717
 718         midQ->midState = MID_REQUEST_SUBMITTED;
 719 #ifdef CONFIG_CIFS_STATS2
 720         atomic_inc(&ses->server->inSend);
 721 #endif
 722         rc = smb_send(ses->server, in_buf, in_buf->smb_buf_length);
 723 #ifdef CONFIG_CIFS_STATS2
 724         atomic_dec(&ses->server->inSend);
 725         midQ->when_sent = jiffies;
 726 #endif
 727         mutex_unlock(&ses->server->srv_mutex);
 728
 729         if (rc < 0)
 730                 goto out;
 731
 732         if (long_op == CIFS_ASYNC_OP)
 733                 goto out;
 734
 735         rc = wait_for_response(ses->server, midQ);
 736         if (rc != 0) {
 737                 spin_lock(&GlobalMid_Lock);
 738                 if (midQ->midState == MID_REQUEST_SUBMITTED) {
 739                         /* no longer considered to be "in-flight" */
 740                         midQ->callback = DeleteMidQEntry;
 741                         spin_unlock(&GlobalMid_Lock);
 742                         atomic_dec(&ses->server->inFlight);
 743                         wake_up(&ses->server->request_q);
 744                         return rc;
 745                 }
 746                 spin_unlock(&GlobalMid_Lock);
 747         }
 748
 749         rc = sync_mid_result(midQ, ses->server);
 750         if (rc != 0) {
 751                 atomic_dec(&ses->server->inFlight);
 752                 wake_up(&ses->server->request_q);
 753                 return rc;
 754         }
 755
 756         receive_len = midQ->resp_buf->smb_buf_length;
 757
 758         if (receive_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) {
 759                 cERROR(1, "Frame too large received.  Length: %d  Xid: %d",
 760                         receive_len, xid);
 761                 rc = -EIO;
 762                 goto out;
 763         }
 764
 765         /* rcvd frame is ok */
 766
 767         if (midQ->resp_buf && out_buf
 768             && (midQ->midState == MID_RESPONSE_RECEIVED)) {
 769                 out_buf->smb_buf_length = receive_len;
 770                 memcpy((char *)out_buf + 4,
 771                        (char *)midQ->resp_buf + 4,
 772                        receive_len);
 773
 774                 dump_smb(out_buf, 92);
 775                 /* convert the length into a more usable form */
 776                 if ((receive_len > 24) &&
 777                     (ses->server->secMode & (SECMODE_SIGN_REQUIRED |
 778                                              SECMODE_SIGN_ENABLED))) {
 779                         rc = cifs_verify_signature(out_buf,
 780                                                 ses->server,
 781                                                 midQ->sequence_number+1);
 782                         if (rc) {
 783                                 cERROR(1, "Unexpected SMB signature");
 784                                 /* BB FIXME add code to kill session */
 785                         }
 786                 }
 787
 788                 *pbytes_returned = out_buf->smb_buf_length;
 789
 790                 /* BB special case reconnect tid and uid here? */
 791                 rc = map_smb_to_linux_error(out_buf, 0 /* no log */ );
 792
 793                 /* convert ByteCount if necessary */
 794                 if (receive_len >= sizeof(struct smb_hdr) - 4
 795                     /* do not count RFC1001 header */  +
 796                     (2 * out_buf->WordCount) + 2 /* bcc */ )
 797                         put_bcc(get_bcc_le(midQ->resp_buf), midQ->resp_buf);
 798         } else {
 799                 rc = -EIO;
 800                 cERROR(1, "Bad MID state?");
 801         }
 802
 803 out:
 804         delete_mid(midQ);
 805         atomic_dec(&ses->server->inFlight);
 806         wake_up(&ses->server->request_q);
 807
 808         return rc;
 809 }
 810
 811 /* We send a LOCKINGX_CANCEL_LOCK to cause the Windows
 812    blocking lock to return. */
 813
 814 static int
 815 send_lock_cancel(const unsigned int xid, struct cifsTconInfo *tcon,
 816                         struct smb_hdr *in_buf,
 817                         struct smb_hdr *out_buf)
 818 {
 819         int bytes_returned;
 820         struct cifsSesInfo *ses = tcon->ses;
 821         LOCK_REQ *pSMB = (LOCK_REQ *)in_buf;
 822
 823         /* We just modify the current in_buf to change
 824            the type of lock from LOCKING_ANDX_SHARED_LOCK
 825            or LOCKING_ANDX_EXCLUSIVE_LOCK to
 826            LOCKING_ANDX_CANCEL_LOCK. */
 827
 828         pSMB->LockType = LOCKING_ANDX_CANCEL_LOCK|LOCKING_ANDX_LARGE_FILES;
 829         pSMB->Timeout = 0;
 830         pSMB->hdr.Mid = GetNextMid(ses->server);
 831
 832         return SendReceive(xid, ses, in_buf, out_buf,
 833                         &bytes_returned, 0);
 834 }
 835
 836 int
 837 SendReceiveBlockingLock(const unsigned int xid, struct cifsTconInfo *tcon,
 838             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
 839             int *pbytes_returned)
 840 {
 841         int rc = 0;
 842         int rstart = 0;
 843         unsigned int receive_len;
 844         struct mid_q_entry *midQ;
 845         struct cifsSesInfo *ses;
 846
 847         if (tcon == NULL || tcon->ses == NULL) {
 848                 cERROR(1, "Null smb session");
 849                 return -EIO;
 850         }
 851         ses = tcon->ses;
 852
 853         if (ses->server == NULL) {
 854                 cERROR(1, "Null tcp session");
 855                 return -EIO;
 856         }
 857
 858         if (ses->server->tcpStatus == CifsExiting)
 859                 return -ENOENT;
 860
 861         /* Ensure that we do not send more than 50 overlapping requests
 862            to the same server. We may make this configurable later or
 863            use ses->maxReq */
 864
 865         if (in_buf->smb_buf_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
 866                 cERROR(1, "Illegal length, greater than maximum frame, %d",
 867                            in_buf->smb_buf_length);
 868                 return -EIO;
 869         }
 870
 871         rc = wait_for_free_request(ses->server, CIFS_BLOCKING_OP);
 872         if (rc)
 873                 return rc;
 874
 875         /* make sure that we sign in the same order that we send on this socket
 876            and avoid races inside tcp sendmsg code that could cause corruption
 877            of smb data */
 878
 879         mutex_lock(&ses->server->srv_mutex);
 880
 881         rc = allocate_mid(ses, in_buf, &midQ);
 882         if (rc) {
 883                 mutex_unlock(&ses->server->srv_mutex);
 884                 return rc;
 885         }
 886
 887         rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
 888         if (rc) {
 889                 delete_mid(midQ);
 890                 mutex_unlock(&ses->server->srv_mutex);
 891                 return rc;
 892         }
 893
 894         midQ->midState = MID_REQUEST_SUBMITTED;
 895 #ifdef CONFIG_CIFS_STATS2
 896         atomic_inc(&ses->server->inSend);
 897 #endif
 898         rc = smb_send(ses->server, in_buf, in_buf->smb_buf_length);
 899 #ifdef CONFIG_CIFS_STATS2
 900         atomic_dec(&ses->server->inSend);
 901         midQ->when_sent = jiffies;
 902 #endif
 903         mutex_unlock(&ses->server->srv_mutex);
 904
 905         if (rc < 0) {
 906                 delete_mid(midQ);
 907                 return rc;
 908         }
 909
 910         /* Wait for a reply - allow signals to interrupt. */
 911         rc = wait_event_interruptible(ses->server->response_q,
 912                 (!(midQ->midState == MID_REQUEST_SUBMITTED)) ||
 913                 ((ses->server->tcpStatus != CifsGood) &&
 914                  (ses->server->tcpStatus != CifsNew)));
 915
 916         /* Were we interrupted by a signal ? */
 917         if ((rc == -ERESTARTSYS) &&
 918                 (midQ->midState == MID_REQUEST_SUBMITTED) &&
 919                 ((ses->server->tcpStatus == CifsGood) ||
 920                  (ses->server->tcpStatus == CifsNew))) {
 921
 922                 if (in_buf->Command == SMB_COM_TRANSACTION2) {
 923                         /* POSIX lock. We send a NT_CANCEL SMB to cause the
 924                            blocking lock to return. */
 925                         rc = send_nt_cancel(ses->server, in_buf, midQ);
 926                         if (rc) {
 927                                 delete_mid(midQ);
 928                                 return rc;
 929                         }
 930                 } else {
 931                         /* Windows lock. We send a LOCKINGX_CANCEL_LOCK
 932                            to cause the blocking lock to return. */
 933
 934                         rc = send_lock_cancel(xid, tcon, in_buf, out_buf);
 935
 936                         /* If we get -ENOLCK back the lock may have
 937                            already been removed. Don't exit in this case. */
 938                         if (rc && rc != -ENOLCK) {
 939                                 delete_mid(midQ);
 940                                 return rc;
 941                         }
 942                 }
 943
 944                 rc = wait_for_response(ses->server, midQ);
 945                 if (rc) {
 946                         spin_lock(&GlobalMid_Lock);
 947                         if (midQ->midState == MID_REQUEST_SUBMITTED) {
 948                                 /* no longer considered to be "in-flight" */
 949                                 midQ->callback = DeleteMidQEntry;
 950                                 spin_unlock(&GlobalMid_Lock);
 951                                 return rc;
 952                         }
 953                         spin_unlock(&GlobalMid_Lock);
 954                 }
 955
 956                 /* We got the response - restart system call. */
 957                 rstart = 1;
 958         }
 959
 960         rc = sync_mid_result(midQ, ses->server);
 961         if (rc != 0)
 962                 return rc;
 963
 964         receive_len = midQ->resp_buf->smb_buf_length;
 965         if (receive_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) {
 966                 cERROR(1, "Frame too large received.  Length: %d  Xid: %d",
 967                         receive_len, xid);
 968                 rc = -EIO;
 969                 goto out;
 970         }
 971
 972         /* rcvd frame is ok */
 973
 974         if ((out_buf == NULL) || (midQ->midState != MID_RESPONSE_RECEIVED)) {
 975                 rc = -EIO;
 976                 cERROR(1, "Bad MID state?");
 977                 goto out;
 978         }
 979
 980         out_buf->smb_buf_length = receive_len;
 981         memcpy((char *)out_buf + 4,
 982                (char *)midQ->resp_buf + 4,
 983                receive_len);
 984
 985         dump_smb(out_buf, 92);
 986         /* convert the length into a more usable form */
 987         if ((receive_len > 24) &&
 988             (ses->server->secMode & (SECMODE_SIGN_REQUIRED |
 989                                      SECMODE_SIGN_ENABLED))) {
 990                 rc = cifs_verify_signature(out_buf,
 991                                            ses->server,
 992                                            midQ->sequence_number+1);
 993                 if (rc) {
 994                         cERROR(1, "Unexpected SMB signature");
 995                         /* BB FIXME add code to kill session */
 996                 }
 997         }
 998
 999         *pbytes_returned = out_buf->smb_buf_length;
1000
1001         /* BB special case reconnect tid and uid here? */
1002         rc = map_smb_to_linux_error(out_buf, 0 /* no log */ );
1003
1004         /* convert ByteCount if necessary */
1005         if (receive_len >= sizeof(struct smb_hdr) - 4
1006             /* do not count RFC1001 header */  +
1007             (2 * out_buf->WordCount) + 2 /* bcc */ )
1008                 put_bcc(get_bcc_le(out_buf), out_buf);
1009
1010 out:
1011         delete_mid(midQ);
1012         if (rstart && rc == -EACCES)
1013                 return -ERESTARTSYS;
1014         return rc;
1015 }