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 = be32_to_cpu(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         total_len = 0;
 148         for (i = 0; i < n_vec; i++)
 149                 total_len += iov[i].iov_len;
 150
 151         cFYI(1, "Sending smb:  total_len %d", total_len);
 152         dump_smb(smb_buffer, len);
 153
 154         i = 0;
 155         while (total_len) {
 156                 rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
 157                                     n_vec - first_vec, total_len);
 158                 if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
 159                         i++;
 160                         /* if blocking send we try 3 times, since each can block
 161                            for 5 seconds. For nonblocking  we have to try more
 162                            but wait increasing amounts of time allowing time for
 163                            socket to clear.  The overall time we wait in either
 164                            case to send on the socket is about 15 seconds.
 165                            Similarly we wait for 15 seconds for
 166                            a response from the server in SendReceive[2]
 167                            for the server to send a response back for
 168                            most types of requests (except SMB Write
 169                            past end of file which can be slow, and
 170                            blocking lock operations). NFS waits slightly longer
 171                            than CIFS, but this can make it take longer for
 172                            nonresponsive servers to be detected and 15 seconds
 173                            is more than enough time for modern networks to
 174                            send a packet.  In most cases if we fail to send
 175                            after the retries we will kill the socket and
 176                            reconnect which may clear the network problem.
 177                         */
 178                         if ((i >= 14) || (!server->noblocksnd && (i > 2))) {
 179                                 cERROR(1, "sends on sock %p stuck for 15 seconds",
 180                                     ssocket);
 181                                 rc = -EAGAIN;
 182                                 break;
 183                         }
 184                         msleep(1 << i);
 185                         continue;
 186                 }
 187                 if (rc < 0)
 188                         break;
 189
 190                 if (rc == total_len) {
 191                         total_len = 0;
 192                         break;
 193                 } else if (rc > total_len) {
 194                         cERROR(1, "sent %d requested %d", rc, total_len);
 195                         break;
 196                 }
 197                 if (rc == 0) {
 198                         /* should never happen, letting socket clear before
 199                            retrying is our only obvious option here */
 200                         cERROR(1, "tcp sent no data");
 201                         msleep(500);
 202                         continue;
 203                 }
 204                 total_len -= rc;
 205                 /* the line below resets i */
 206                 for (i = first_vec; i < n_vec; i++) {
 207                         if (iov[i].iov_len) {
 208                                 if (rc > iov[i].iov_len) {
 209                                         rc -= iov[i].iov_len;
 210                                         iov[i].iov_len = 0;
 211                                 } else {
 212                                         iov[i].iov_base += rc;
 213                                         iov[i].iov_len -= rc;
 214                                         first_vec = i;
 215                                         break;
 216                                 }
 217                         }
 218                 }
 219                 i = 0; /* in case we get ENOSPC on the next send */
 220         }
 221
 222         if ((total_len > 0) && (total_len != smb_buf_length + 4)) {
 223                 cFYI(1, "partial send (%d remaining), terminating session",
 224                         total_len);
 225                 /* If we have only sent part of an SMB then the next SMB
 226                    could be taken as the remainder of this one.  We need
 227                    to kill the socket so the server throws away the partial
 228                    SMB */
 229                 server->tcpStatus = CifsNeedReconnect;
 230         }
 231
 232         if (rc < 0 && rc != -EINTR)
 233                 cERROR(1, "Error %d sending data on socket to server", rc);
 234         else
 235                 rc = 0;
 236
 237         /* Don't want to modify the buffer as a
 238            side effect of this call. */
 239         smb_buffer->smb_buf_length = cpu_to_be32(smb_buf_length);
 240
 241         return rc;
 242 }
 243
 244 int
 245 smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
 246          unsigned int smb_buf_length)
 247 {
 248         struct kvec iov;
 249
 250         iov.iov_base = smb_buffer;
 251         iov.iov_len = smb_buf_length + 4;
 252
 253         return smb_sendv(server, &iov, 1);
 254 }
 255
 256 static int wait_for_free_request(struct TCP_Server_Info *server,
 257                                  const int long_op)
 258 {
 259         if (long_op == CIFS_ASYNC_OP) {
 260                 /* oplock breaks must not be held up */
 261                 atomic_inc(&server->inFlight);
 262                 return 0;
 263         }
 264
 265         spin_lock(&GlobalMid_Lock);
 266         while (1) {
 267                 if (atomic_read(&server->inFlight) >= cifs_max_pending) {
 268                         spin_unlock(&GlobalMid_Lock);
 269                         cifs_num_waiters_inc(server);
 270                         wait_event(server->request_q,
 271                                    atomic_read(&server->inFlight)
 272                                      < cifs_max_pending);
 273                         cifs_num_waiters_dec(server);
 274                         spin_lock(&GlobalMid_Lock);
 275                 } else {
 276                         if (server->tcpStatus == CifsExiting) {
 277                                 spin_unlock(&GlobalMid_Lock);
 278                                 return -ENOENT;
 279                         }
 280
 281                         /* can not count locking commands against total
 282                            as they are allowed to block on server */
 283
 284                         /* update # of requests on the wire to server */
 285                         if (long_op != CIFS_BLOCKING_OP)
 286                                 atomic_inc(&server->inFlight);
 287                         spin_unlock(&GlobalMid_Lock);
 288                         break;
 289                 }
 290         }
 291         return 0;
 292 }
 293
 294 static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,
 295                         struct mid_q_entry **ppmidQ)
 296 {
 297         if (ses->server->tcpStatus == CifsExiting) {
 298                 return -ENOENT;
 299         }
 300
 301         if (ses->server->tcpStatus == CifsNeedReconnect) {
 302                 cFYI(1, "tcp session dead - return to caller to retry");
 303                 return -EAGAIN;
 304         }
 305
 306         if (ses->status != CifsGood) {
 307                 /* check if SMB session is bad because we are setting it up */
 308                 if ((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
 309                         (in_buf->Command != SMB_COM_NEGOTIATE))
 310                         return -EAGAIN;
 311                 /* else ok - we are setting up session */
 312         }
 313         *ppmidQ = AllocMidQEntry(in_buf, ses->server);
 314         if (*ppmidQ == NULL)
 315                 return -ENOMEM;
 316         spin_lock(&GlobalMid_Lock);
 317         list_add_tail(&(*ppmidQ)->qhead, &ses->server->pending_mid_q);
 318         spin_unlock(&GlobalMid_Lock);
 319         return 0;
 320 }
 321
 322 static int
 323 wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
 324 {
 325         int error;
 326
 327         error = wait_event_killable(server->response_q,
 328                                     midQ->midState != MID_REQUEST_SUBMITTED);
 329         if (error < 0)
 330                 return -ERESTARTSYS;
 331
 332         return 0;
 333 }
 334
 335
 336 /*
 337  * Send a SMB request and set the callback function in the mid to handle
 338  * the result. Caller is responsible for dealing with timeouts.
 339  */
 340 int
 341 cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
 342                 unsigned int nvec, mid_callback_t *callback, void *cbdata,
 343                 bool ignore_pend)
 344 {
 345         int rc;
 346         struct mid_q_entry *mid;
 347         struct smb_hdr *hdr = (struct smb_hdr *)iov[0].iov_base;
 348
 349         rc = wait_for_free_request(server, ignore_pend ? CIFS_ASYNC_OP : 0);
 350         if (rc)
 351                 return rc;
 352
 353         /* enable signing if server requires it */
 354         if (server->sec_mode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
 355                 hdr->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 356
 357         mutex_lock(&server->srv_mutex);
 358         mid = AllocMidQEntry(hdr, server);
 359         if (mid == NULL) {
 360                 mutex_unlock(&server->srv_mutex);
 361                 atomic_dec(&server->inFlight);
 362                 wake_up(&server->request_q);
 363                 return -ENOMEM;
 364         }
 365
 366         /* put it on the pending_mid_q */
 367         spin_lock(&GlobalMid_Lock);
 368         list_add_tail(&mid->qhead, &server->pending_mid_q);
 369         spin_unlock(&GlobalMid_Lock);
 370
 371         rc = cifs_sign_smb2(iov, nvec, server, &mid->sequence_number);
 372         if (rc) {
 373                 mutex_unlock(&server->srv_mutex);
 374                 goto out_err;
 375         }
 376
 377         mid->callback = callback;
 378         mid->callback_data = cbdata;
 379         mid->midState = MID_REQUEST_SUBMITTED;
 380
 381         cifs_in_send_inc(server);
 382         rc = smb_sendv(server, iov, nvec);
 383         cifs_in_send_dec(server);
 384         cifs_save_when_sent(mid);
 385         mutex_unlock(&server->srv_mutex);
 386
 387         if (rc)
 388                 goto out_err;
 389
 390         return rc;
 391 out_err:
 392         delete_mid(mid);
 393         atomic_dec(&server->inFlight);
 394         wake_up(&server->request_q);
 395         return rc;
 396 }
 397
 398 /*
 399  *
 400  * Send an SMB Request.  No response info (other than return code)
 401  * needs to be parsed.
 402  *
 403  * flags indicate the type of request buffer and how long to wait
 404  * and whether to log NT STATUS code (error) before mapping it to POSIX error
 405  *
 406  */
 407 int
 408 SendReceiveNoRsp(const unsigned int xid, struct cifs_ses *ses,
 409                 struct smb_hdr *in_buf, int flags)
 410 {
 411         int rc;
 412         struct kvec iov[1];
 413         int resp_buf_type;
 414
 415         iov[0].iov_base = (char *)in_buf;
 416         iov[0].iov_len = be32_to_cpu(in_buf->smb_buf_length) + 4;
 417         flags |= CIFS_NO_RESP;
 418         rc = SendReceive2(xid, ses, iov, 1, &resp_buf_type, flags);
 419         cFYI(DBG2, "SendRcvNoRsp flags %d rc %d", flags, rc);
 420
 421         return rc;
 422 }
 423
 424 static int
 425 cifs_sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
 426 {
 427         int rc = 0;
 428
 429         cFYI(1, "%s: cmd=%d mid=%d state=%d", __func__, mid->command,
 430                 mid->mid, mid->midState);
 431
 432         spin_lock(&GlobalMid_Lock);
 433         switch (mid->midState) {
 434         case MID_RESPONSE_RECEIVED:
 435                 spin_unlock(&GlobalMid_Lock);
 436                 return rc;
 437         case MID_RETRY_NEEDED:
 438                 rc = -EAGAIN;
 439                 break;
 440         case MID_RESPONSE_MALFORMED:
 441                 rc = -EIO;
 442                 break;
 443         case MID_SHUTDOWN:
 444                 rc = -EHOSTDOWN;
 445                 break;
 446         default:
 447                 list_del_init(&mid->qhead);
 448                 cERROR(1, "%s: invalid mid state mid=%d state=%d", __func__,
 449                         mid->mid, mid->midState);
 450                 rc = -EIO;
 451         }
 452         spin_unlock(&GlobalMid_Lock);
 453
 454         DeleteMidQEntry(mid);
 455         return rc;
 456 }
 457
 458 /*
 459  * An NT cancel request header looks just like the original request except:
 460  *
 461  * The Command is SMB_COM_NT_CANCEL
 462  * The WordCount is zeroed out
 463  * The ByteCount is zeroed out
 464  *
 465  * This function mangles an existing request buffer into a
 466  * SMB_COM_NT_CANCEL request and then sends it.
 467  */
 468 static int
 469 send_nt_cancel(struct TCP_Server_Info *server, struct smb_hdr *in_buf,
 470                 struct mid_q_entry *mid)
 471 {
 472         int rc = 0;
 473
 474         /* -4 for RFC1001 length and +2 for BCC field */
 475         in_buf->smb_buf_length = cpu_to_be32(sizeof(struct smb_hdr) - 4  + 2);
 476         in_buf->Command = SMB_COM_NT_CANCEL;
 477         in_buf->WordCount = 0;
 478         put_bcc(0, in_buf);
 479
 480         mutex_lock(&server->srv_mutex);
 481         rc = cifs_sign_smb(in_buf, server, &mid->sequence_number);
 482         if (rc) {
 483                 mutex_unlock(&server->srv_mutex);
 484                 return rc;
 485         }
 486         rc = smb_send(server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
 487         mutex_unlock(&server->srv_mutex);
 488
 489         cFYI(1, "issued NT_CANCEL for mid %u, rc = %d",
 490                 in_buf->Mid, rc);
 491
 492         return rc;
 493 }
 494
 495 int
 496 cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 497                    bool log_error)
 498 {
 499         dump_smb(mid->resp_buf,
 500                  min_t(u32, 92, be32_to_cpu(mid->resp_buf->smb_buf_length)));
 501
 502         /* convert the length into a more usable form */
 503         if (server->sec_mode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
 504                 /* FIXME: add code to kill session */
 505                 if (cifs_verify_signature(mid->resp_buf, server,
 506                                           mid->sequence_number + 1) != 0)
 507                         cERROR(1, "Unexpected SMB signature");
 508         }
 509
 510         /* BB special case reconnect tid and uid here? */
 511         return map_smb_to_linux_error(mid->resp_buf, log_error);
 512 }
 513
 514 int
 515 SendReceive2(const unsigned int xid, struct cifs_ses *ses,
 516              struct kvec *iov, int n_vec, int *pRespBufType /* ret */,
 517              const int flags)
 518 {
 519         int rc = 0;
 520         int long_op;
 521         struct mid_q_entry *midQ;
 522         struct smb_hdr *in_buf = iov[0].iov_base;
 523
 524         long_op = flags & CIFS_TIMEOUT_MASK;
 525
 526         *pRespBufType = CIFS_NO_BUFFER;  /* no response buf yet */
 527
 528         if ((ses == NULL) || (ses->server == NULL)) {
 529                 cifs_small_buf_release(in_buf);
 530                 cERROR(1, "Null session");
 531                 return -EIO;
 532         }
 533
 534         if (ses->server->tcpStatus == CifsExiting) {
 535                 cifs_small_buf_release(in_buf);
 536                 return -ENOENT;
 537         }
 538
 539         /* Ensure that we do not send more than 50 overlapping requests
 540            to the same server. We may make this configurable later or
 541            use ses->maxReq */
 542
 543         rc = wait_for_free_request(ses->server, long_op);
 544         if (rc) {
 545                 cifs_small_buf_release(in_buf);
 546                 return rc;
 547         }
 548
 549         /* make sure that we sign in the same order that we send on this socket
 550            and avoid races inside tcp sendmsg code that could cause corruption
 551            of smb data */
 552
 553         mutex_lock(&ses->server->srv_mutex);
 554
 555         rc = allocate_mid(ses, in_buf, &midQ);
 556         if (rc) {
 557                 mutex_unlock(&ses->server->srv_mutex);
 558                 cifs_small_buf_release(in_buf);
 559                 /* Update # of requests on wire to server */
 560                 atomic_dec(&ses->server->inFlight);
 561                 wake_up(&ses->server->request_q);
 562                 return rc;
 563         }
 564         rc = cifs_sign_smb2(iov, n_vec, ses->server, &midQ->sequence_number);
 565         if (rc) {
 566                 mutex_unlock(&ses->server->srv_mutex);
 567                 cifs_small_buf_release(in_buf);
 568                 goto out;
 569         }
 570
 571         midQ->midState = MID_REQUEST_SUBMITTED;
 572         cifs_in_send_inc(ses->server);
 573         rc = smb_sendv(ses->server, iov, n_vec);
 574         cifs_in_send_dec(ses->server);
 575         cifs_save_when_sent(midQ);
 576
 577         mutex_unlock(&ses->server->srv_mutex);
 578
 579         if (rc < 0) {
 580                 cifs_small_buf_release(in_buf);
 581                 goto out;
 582         }
 583
 584         if (long_op == CIFS_ASYNC_OP) {
 585                 cifs_small_buf_release(in_buf);
 586                 goto out;
 587         }
 588
 589         rc = wait_for_response(ses->server, midQ);
 590         if (rc != 0) {
 591                 send_nt_cancel(ses->server, in_buf, midQ);
 592                 spin_lock(&GlobalMid_Lock);
 593                 if (midQ->midState == MID_REQUEST_SUBMITTED) {
 594                         midQ->callback = DeleteMidQEntry;
 595                         spin_unlock(&GlobalMid_Lock);
 596                         cifs_small_buf_release(in_buf);
 597                         atomic_dec(&ses->server->inFlight);
 598                         wake_up(&ses->server->request_q);
 599                         return rc;
 600                 }
 601                 spin_unlock(&GlobalMid_Lock);
 602         }
 603
 604         cifs_small_buf_release(in_buf);
 605
 606         rc = cifs_sync_mid_result(midQ, ses->server);
 607         if (rc != 0) {
 608                 atomic_dec(&ses->server->inFlight);
 609                 wake_up(&ses->server->request_q);
 610                 return rc;
 611         }
 612
 613         if (!midQ->resp_buf || midQ->midState != MID_RESPONSE_RECEIVED) {
 614                 rc = -EIO;
 615                 cFYI(1, "Bad MID state?");
 616                 goto out;
 617         }
 618
 619         iov[0].iov_base = (char *)midQ->resp_buf;
 620         iov[0].iov_len = be32_to_cpu(midQ->resp_buf->smb_buf_length) + 4;
 621         if (midQ->largeBuf)
 622                 *pRespBufType = CIFS_LARGE_BUFFER;
 623         else
 624                 *pRespBufType = CIFS_SMALL_BUFFER;
 625
 626         rc = cifs_check_receive(midQ, ses->server, flags & CIFS_LOG_ERROR);
 627
 628         /* mark it so buf will not be freed by delete_mid */
 629         if ((flags & CIFS_NO_RESP) == 0)
 630                 midQ->resp_buf = NULL;
 631 out:
 632         delete_mid(midQ);
 633         atomic_dec(&ses->server->inFlight);
 634         wake_up(&ses->server->request_q);
 635
 636         return rc;
 637 }
 638
 639 int
 640 SendReceive(const unsigned int xid, struct cifs_ses *ses,
 641             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
 642             int *pbytes_returned, const int long_op)
 643 {
 644         int rc = 0;
 645         struct mid_q_entry *midQ;
 646
 647         if (ses == NULL) {
 648                 cERROR(1, "Null smb session");
 649                 return -EIO;
 650         }
 651         if (ses->server == NULL) {
 652                 cERROR(1, "Null tcp session");
 653                 return -EIO;
 654         }
 655
 656         if (ses->server->tcpStatus == CifsExiting)
 657                 return -ENOENT;
 658
 659         /* Ensure that we do not send more than 50 overlapping requests
 660            to the same server. We may make this configurable later or
 661            use ses->maxReq */
 662
 663         if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
 664                         MAX_CIFS_HDR_SIZE - 4) {
 665                 cERROR(1, "Illegal length, greater than maximum frame, %d",
 666                            be32_to_cpu(in_buf->smb_buf_length));
 667                 return -EIO;
 668         }
 669
 670         rc = wait_for_free_request(ses->server, long_op);
 671         if (rc)
 672                 return rc;
 673
 674         /* make sure that we sign in the same order that we send on this socket
 675            and avoid races inside tcp sendmsg code that could cause corruption
 676            of smb data */
 677
 678         mutex_lock(&ses->server->srv_mutex);
 679
 680         rc = allocate_mid(ses, in_buf, &midQ);
 681         if (rc) {
 682                 mutex_unlock(&ses->server->srv_mutex);
 683                 /* Update # of requests on wire to server */
 684                 atomic_dec(&ses->server->inFlight);
 685                 wake_up(&ses->server->request_q);
 686                 return rc;
 687         }
 688
 689         rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
 690         if (rc) {
 691                 mutex_unlock(&ses->server->srv_mutex);
 692                 goto out;
 693         }
 694
 695         midQ->midState = MID_REQUEST_SUBMITTED;
 696
 697         cifs_in_send_inc(ses->server);
 698         rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
 699         cifs_in_send_dec(ses->server);
 700         cifs_save_when_sent(midQ);
 701         mutex_unlock(&ses->server->srv_mutex);
 702
 703         if (rc < 0)
 704                 goto out;
 705
 706         if (long_op == CIFS_ASYNC_OP)
 707                 goto out;
 708
 709         rc = wait_for_response(ses->server, midQ);
 710         if (rc != 0) {
 711                 send_nt_cancel(ses->server, in_buf, midQ);
 712                 spin_lock(&GlobalMid_Lock);
 713                 if (midQ->midState == MID_REQUEST_SUBMITTED) {
 714                         /* no longer considered to be "in-flight" */
 715                         midQ->callback = DeleteMidQEntry;
 716                         spin_unlock(&GlobalMid_Lock);
 717                         atomic_dec(&ses->server->inFlight);
 718                         wake_up(&ses->server->request_q);
 719                         return rc;
 720                 }
 721                 spin_unlock(&GlobalMid_Lock);
 722         }
 723
 724         rc = cifs_sync_mid_result(midQ, ses->server);
 725         if (rc != 0) {
 726                 atomic_dec(&ses->server->inFlight);
 727                 wake_up(&ses->server->request_q);
 728                 return rc;
 729         }
 730
 731         if (!midQ->resp_buf || !out_buf ||
 732             midQ->midState != MID_RESPONSE_RECEIVED) {
 733                 rc = -EIO;
 734                 cERROR(1, "Bad MID state?");
 735                 goto out;
 736         }
 737
 738         *pbytes_returned = be32_to_cpu(midQ->resp_buf->smb_buf_length);
 739         memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
 740         rc = cifs_check_receive(midQ, ses->server, 0);
 741 out:
 742         delete_mid(midQ);
 743         atomic_dec(&ses->server->inFlight);
 744         wake_up(&ses->server->request_q);
 745
 746         return rc;
 747 }
 748
 749 /* We send a LOCKINGX_CANCEL_LOCK to cause the Windows
 750    blocking lock to return. */
 751
 752 static int
 753 send_lock_cancel(const unsigned int xid, struct cifs_tcon *tcon,
 754                         struct smb_hdr *in_buf,
 755                         struct smb_hdr *out_buf)
 756 {
 757         int bytes_returned;
 758         struct cifs_ses *ses = tcon->ses;
 759         LOCK_REQ *pSMB = (LOCK_REQ *)in_buf;
 760
 761         /* We just modify the current in_buf to change
 762            the type of lock from LOCKING_ANDX_SHARED_LOCK
 763            or LOCKING_ANDX_EXCLUSIVE_LOCK to
 764            LOCKING_ANDX_CANCEL_LOCK. */
 765
 766         pSMB->LockType = LOCKING_ANDX_CANCEL_LOCK|LOCKING_ANDX_LARGE_FILES;
 767         pSMB->Timeout = 0;
 768         pSMB->hdr.Mid = GetNextMid(ses->server);
 769
 770         return SendReceive(xid, ses, in_buf, out_buf,
 771                         &bytes_returned, 0);
 772 }
 773
 774 int
 775 SendReceiveBlockingLock(const unsigned int xid, struct cifs_tcon *tcon,
 776             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
 777             int *pbytes_returned)
 778 {
 779         int rc = 0;
 780         int rstart = 0;
 781         struct mid_q_entry *midQ;
 782         struct cifs_ses *ses;
 783
 784         if (tcon == NULL || tcon->ses == NULL) {
 785                 cERROR(1, "Null smb session");
 786                 return -EIO;
 787         }
 788         ses = tcon->ses;
 789
 790         if (ses->server == NULL) {
 791                 cERROR(1, "Null tcp session");
 792                 return -EIO;
 793         }
 794
 795         if (ses->server->tcpStatus == CifsExiting)
 796                 return -ENOENT;
 797
 798         /* Ensure that we do not send more than 50 overlapping requests
 799            to the same server. We may make this configurable later or
 800            use ses->maxReq */
 801
 802         if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
 803                         MAX_CIFS_HDR_SIZE - 4) {
 804                 cERROR(1, "Illegal length, greater than maximum frame, %d",
 805                            be32_to_cpu(in_buf->smb_buf_length));
 806                 return -EIO;
 807         }
 808
 809         rc = wait_for_free_request(ses->server, CIFS_BLOCKING_OP);
 810         if (rc)
 811                 return rc;
 812
 813         /* make sure that we sign in the same order that we send on this socket
 814            and avoid races inside tcp sendmsg code that could cause corruption
 815            of smb data */
 816
 817         mutex_lock(&ses->server->srv_mutex);
 818
 819         rc = allocate_mid(ses, in_buf, &midQ);
 820         if (rc) {
 821                 mutex_unlock(&ses->server->srv_mutex);
 822                 return rc;
 823         }
 824
 825         rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
 826         if (rc) {
 827                 delete_mid(midQ);
 828                 mutex_unlock(&ses->server->srv_mutex);
 829                 return rc;
 830         }
 831
 832         midQ->midState = MID_REQUEST_SUBMITTED;
 833         cifs_in_send_inc(ses->server);
 834         rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
 835         cifs_in_send_dec(ses->server);
 836         cifs_save_when_sent(midQ);
 837         mutex_unlock(&ses->server->srv_mutex);
 838
 839         if (rc < 0) {
 840                 delete_mid(midQ);
 841                 return rc;
 842         }
 843
 844         /* Wait for a reply - allow signals to interrupt. */
 845         rc = wait_event_interruptible(ses->server->response_q,
 846                 (!(midQ->midState == MID_REQUEST_SUBMITTED)) ||
 847                 ((ses->server->tcpStatus != CifsGood) &&
 848                  (ses->server->tcpStatus != CifsNew)));
 849
 850         /* Were we interrupted by a signal ? */
 851         if ((rc == -ERESTARTSYS) &&
 852                 (midQ->midState == MID_REQUEST_SUBMITTED) &&
 853                 ((ses->server->tcpStatus == CifsGood) ||
 854                  (ses->server->tcpStatus == CifsNew))) {
 855
 856                 if (in_buf->Command == SMB_COM_TRANSACTION2) {
 857                         /* POSIX lock. We send a NT_CANCEL SMB to cause the
 858                            blocking lock to return. */
 859                         rc = send_nt_cancel(ses->server, in_buf, midQ);
 860                         if (rc) {
 861                                 delete_mid(midQ);
 862                                 return rc;
 863                         }
 864                 } else {
 865                         /* Windows lock. We send a LOCKINGX_CANCEL_LOCK
 866                            to cause the blocking lock to return. */
 867
 868                         rc = send_lock_cancel(xid, tcon, in_buf, out_buf);
 869
 870                         /* If we get -ENOLCK back the lock may have
 871                            already been removed. Don't exit in this case. */
 872                         if (rc && rc != -ENOLCK) {
 873                                 delete_mid(midQ);
 874                                 return rc;
 875                         }
 876                 }
 877
 878                 rc = wait_for_response(ses->server, midQ);
 879                 if (rc) {
 880                         send_nt_cancel(ses->server, in_buf, midQ);
 881                         spin_lock(&GlobalMid_Lock);
 882                         if (midQ->midState == MID_REQUEST_SUBMITTED) {
 883                                 /* no longer considered to be "in-flight" */
 884                                 midQ->callback = DeleteMidQEntry;
 885                                 spin_unlock(&GlobalMid_Lock);
 886                                 return rc;
 887                         }
 888                         spin_unlock(&GlobalMid_Lock);
 889                 }
 890
 891                 /* We got the response - restart system call. */
 892                 rstart = 1;
 893         }
 894
 895         rc = cifs_sync_mid_result(midQ, ses->server);
 896         if (rc != 0)
 897                 return rc;
 898
 899         /* rcvd frame is ok */
 900         if (out_buf == NULL || midQ->midState != MID_RESPONSE_RECEIVED) {
 901                 rc = -EIO;
 902                 cERROR(1, "Bad MID state?");
 903                 goto out;
 904         }
 905
 906         *pbytes_returned = be32_to_cpu(midQ->resp_buf->smb_buf_length);
 907         memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
 908         rc = cifs_check_receive(midQ, ses->server, 0);
 909 out:
 910         delete_mid(midQ);
 911         if (rstart && rc == -EACCES)
 912                 return -ERESTARTSYS;
 913         return rc;
 914 }