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 <linux/freezer.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/processor.h>
  32 #include <linux/mempool.h>
  33 #include "cifspdu.h"
  34 #include "cifsglob.h"
  35 #include "cifsproto.h"
  36 #include "cifs_debug.h"
  37
  38 extern mempool_t *cifs_mid_poolp;
  39
  40 static void
  41 wake_up_task(struct mid_q_entry *mid)
  42 {
  43         wake_up_process(mid->callback_data);
  44 }
  45
  46 struct mid_q_entry *
  47 AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
  48 {
  49         struct mid_q_entry *temp;
  50
  51         if (server == NULL) {
  52                 cERROR(1, "Null TCP session in AllocMidQEntry");
  53                 return NULL;
  54         }
  55
  56         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
  57         if (temp == NULL)
  58                 return temp;
  59         else {
  60                 memset(temp, 0, sizeof(struct mid_q_entry));
  61                 temp->mid = smb_buffer->Mid;    /* always LE */
  62                 temp->pid = current->pid;
  63                 temp->command = cpu_to_le16(smb_buffer->Command);
  64                 cFYI(1, "For smb_command %d", smb_buffer->Command);
  65         /*      do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */
  66                 /* when mid allocated can be before when sent */
  67                 temp->when_alloc = jiffies;
  68
  69                 /*
  70                  * The default is for the mid to be synchronous, so the
  71                  * default callback just wakes up the current task.
  72                  */
  73                 temp->callback = wake_up_task;
  74                 temp->callback_data = current;
  75         }
  76
  77         atomic_inc(&midCount);
  78         temp->mid_state = MID_REQUEST_ALLOCATED;
  79         return temp;
  80 }
  81
  82 void
  83 DeleteMidQEntry(struct mid_q_entry *midEntry)
  84 {
  85 #ifdef CONFIG_CIFS_STATS2
  86         unsigned long now;
  87 #endif
  88         midEntry->mid_state = MID_FREE;
  89         atomic_dec(&midCount);
  90         if (midEntry->large_buf)
  91                 cifs_buf_release(midEntry->resp_buf);
  92         else
  93                 cifs_small_buf_release(midEntry->resp_buf);
  94 #ifdef CONFIG_CIFS_STATS2
  95         now = jiffies;
  96         /* commands taking longer than one second are indications that
  97            something is wrong, unless it is quite a slow link or server */
  98         if ((now - midEntry->when_alloc) > HZ) {
  99                 if ((cifsFYI & CIFS_TIMER) &&
 100                     (midEntry->command != cpu_to_le16(SMB_COM_LOCKING_ANDX))) {
 101                         printk(KERN_DEBUG " CIFS slow rsp: cmd %d mid %llu",
 102                                midEntry->command, midEntry->mid);
 103                         printk(" A: 0x%lx S: 0x%lx R: 0x%lx\n",
 104                                now - midEntry->when_alloc,
 105                                now - midEntry->when_sent,
 106                                now - midEntry->when_received);
 107                 }
 108         }
 109 #endif
 110         mempool_free(midEntry, cifs_mid_poolp);
 111 }
 112
 113 static void
 114 delete_mid(struct mid_q_entry *mid)
 115 {
 116         spin_lock(&GlobalMid_Lock);
 117         list_del(&mid->qhead);
 118         spin_unlock(&GlobalMid_Lock);
 119
 120         DeleteMidQEntry(mid);
 121 }
 122
 123 static int
 124 smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
 125 {
 126         int rc = 0;
 127         int i = 0;
 128         struct msghdr smb_msg;
 129         __be32 *buf_len = (__be32 *)(iov[0].iov_base);
 130         unsigned int len = iov[0].iov_len;
 131         unsigned int total_len;
 132         int first_vec = 0;
 133         unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);
 134         struct socket *ssocket = server->ssocket;
 135
 136         if (ssocket == NULL)
 137                 return -ENOTSOCK; /* BB eventually add reconnect code here */
 138
 139         smb_msg.msg_name = (struct sockaddr *) &server->dstaddr;
 140         smb_msg.msg_namelen = sizeof(struct sockaddr);
 141         smb_msg.msg_control = NULL;
 142         smb_msg.msg_controllen = 0;
 143         if (server->noblocksnd)
 144                 smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL;
 145         else
 146                 smb_msg.msg_flags = MSG_NOSIGNAL;
 147
 148         total_len = 0;
 149         for (i = 0; i < n_vec; i++)
 150                 total_len += iov[i].iov_len;
 151
 152         cFYI(1, "Sending smb:  total_len %d", total_len);
 153         dump_smb(iov[0].iov_base, len);
 154
 155         i = 0;
 156         while (total_len) {
 157                 rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
 158                                     n_vec - first_vec, total_len);
 159                 if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
 160                         i++;
 161                         /*
 162                          * If blocking send we try 3 times, since each can block
 163                          * for 5 seconds. For nonblocking  we have to try more
 164                          * but wait increasing amounts of time allowing time for
 165                          * socket to clear.  The overall time we wait in either
 166                          * case to send on the socket is about 15 seconds.
 167                          * Similarly we wait for 15 seconds for a response from
 168                          * the server in SendReceive[2] for the server to send
 169                          * a response back for most types of requests (except
 170                          * SMB Write past end of file which can be slow, and
 171                          * blocking lock operations). NFS waits slightly longer
 172                          * than CIFS, but this can make it take longer for
 173                          * nonresponsive servers to be detected and 15 seconds
 174                          * is more than enough time for modern networks to
 175                          * send a packet.  In most cases if we fail to send
 176                          * after the retries we will kill the socket and
 177                          * reconnect which may clear the network problem.
 178                          */
 179                         if ((i >= 14) || (!server->noblocksnd && (i > 2))) {
 180                                 cERROR(1, "sends on sock %p stuck for 15 seconds",
 181                                     ssocket);
 182                                 rc = -EAGAIN;
 183                                 break;
 184                         }
 185                         msleep(1 << i);
 186                         continue;
 187                 }
 188                 if (rc < 0)
 189                         break;
 190
 191                 if (rc == total_len) {
 192                         total_len = 0;
 193                         break;
 194                 } else if (rc > total_len) {
 195                         cERROR(1, "sent %d requested %d", rc, total_len);
 196                         break;
 197                 }
 198                 if (rc == 0) {
 199                         /* should never happen, letting socket clear before
 200                            retrying is our only obvious option here */
 201                         cERROR(1, "tcp sent no data");
 202                         msleep(500);
 203                         continue;
 204                 }
 205                 total_len -= rc;
 206                 /* the line below resets i */
 207                 for (i = first_vec; i < n_vec; i++) {
 208                         if (iov[i].iov_len) {
 209                                 if (rc > iov[i].iov_len) {
 210                                         rc -= iov[i].iov_len;
 211                                         iov[i].iov_len = 0;
 212                                 } else {
 213                                         iov[i].iov_base += rc;
 214                                         iov[i].iov_len -= rc;
 215                                         first_vec = i;
 216                                         break;
 217                                 }
 218                         }
 219                 }
 220                 i = 0; /* in case we get ENOSPC on the next send */
 221         }
 222
 223         if ((total_len > 0) && (total_len != smb_buf_length + 4)) {
 224                 cFYI(1, "partial send (%d remaining), terminating session",
 225                         total_len);
 226                 /* If we have only sent part of an SMB then the next SMB
 227                    could be taken as the remainder of this one.  We need
 228                    to kill the socket so the server throws away the partial
 229                    SMB */
 230                 server->tcpStatus = CifsNeedReconnect;
 231         }
 232
 233         if (rc < 0 && rc != -EINTR)
 234                 cERROR(1, "Error %d sending data on socket to server", rc);
 235         else
 236                 rc = 0;
 237
 238         /* Don't want to modify the buffer as a side effect of this call. */
 239         *buf_len = 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
 257 wait_for_free_credits(struct TCP_Server_Info *server, const int optype,
 258                       int *credits)
 259 {
 260         int rc;
 261
 262         spin_lock(&server->req_lock);
 263         if (optype == CIFS_ASYNC_OP) {
 264                 /* oplock breaks must not be held up */
 265                 server->in_flight++;
 266                 *credits -= 1;
 267                 spin_unlock(&server->req_lock);
 268                 return 0;
 269         }
 270
 271         while (1) {
 272                 if (*credits <= 0) {
 273                         spin_unlock(&server->req_lock);
 274                         cifs_num_waiters_inc(server);
 275                         rc = wait_event_killable(server->request_q,
 276                                                  has_credits(server, credits));
 277                         cifs_num_waiters_dec(server);
 278                         if (rc)
 279                                 return rc;
 280                         spin_lock(&server->req_lock);
 281                 } else {
 282                         if (server->tcpStatus == CifsExiting) {
 283                                 spin_unlock(&server->req_lock);
 284                                 return -ENOENT;
 285                         }
 286
 287                         /*
 288                          * Can not count locking commands against total
 289                          * as they are allowed to block on server.
 290                          */
 291
 292                         /* update # of requests on the wire to server */
 293                         if (optype != CIFS_BLOCKING_OP) {
 294                                 *credits -= 1;
 295                                 server->in_flight++;
 296                         }
 297                         spin_unlock(&server->req_lock);
 298                         break;
 299                 }
 300         }
 301         return 0;
 302 }
 303
 304 static int
 305 wait_for_free_request(struct TCP_Server_Info *server, const int optype)
 306 {
 307         return wait_for_free_credits(server, optype,
 308                                      server->ops->get_credits_field(server));
 309 }
 310
 311 static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,
 312                         struct mid_q_entry **ppmidQ)
 313 {
 314         if (ses->server->tcpStatus == CifsExiting) {
 315                 return -ENOENT;
 316         }
 317
 318         if (ses->server->tcpStatus == CifsNeedReconnect) {
 319                 cFYI(1, "tcp session dead - return to caller to retry");
 320                 return -EAGAIN;
 321         }
 322
 323         if (ses->status != CifsGood) {
 324                 /* check if SMB session is bad because we are setting it up */
 325                 if ((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
 326                         (in_buf->Command != SMB_COM_NEGOTIATE))
 327                         return -EAGAIN;
 328                 /* else ok - we are setting up session */
 329         }
 330         *ppmidQ = AllocMidQEntry(in_buf, ses->server);
 331         if (*ppmidQ == NULL)
 332                 return -ENOMEM;
 333         spin_lock(&GlobalMid_Lock);
 334         list_add_tail(&(*ppmidQ)->qhead, &ses->server->pending_mid_q);
 335         spin_unlock(&GlobalMid_Lock);
 336         return 0;
 337 }
 338
 339 static int
 340 wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
 341 {
 342         int error;
 343
 344         error = wait_event_freezekillable(server->response_q,
 345                                     midQ->mid_state != MID_REQUEST_SUBMITTED);
 346         if (error < 0)
 347                 return -ERESTARTSYS;
 348
 349         return 0;
 350 }
 351
 352 static int
 353 cifs_setup_async_request(struct TCP_Server_Info *server, struct kvec *iov,
 354                          unsigned int nvec, struct mid_q_entry **ret_mid)
 355 {
 356         int rc;
 357         struct smb_hdr *hdr = (struct smb_hdr *)iov[0].iov_base;
 358         struct mid_q_entry *mid;
 359
 360         /* enable signing if server requires it */
 361         if (server->sec_mode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
 362                 hdr->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 363
 364         mid = AllocMidQEntry(hdr, server);
 365         if (mid == NULL)
 366                 return -ENOMEM;
 367
 368         /* put it on the pending_mid_q */
 369         spin_lock(&GlobalMid_Lock);
 370         list_add_tail(&mid->qhead, &server->pending_mid_q);
 371         spin_unlock(&GlobalMid_Lock);
 372
 373         rc = cifs_sign_smb2(iov, nvec, server, &mid->sequence_number);
 374         if (rc)
 375                 delete_mid(mid);
 376         *ret_mid = mid;
 377         return rc;
 378 }
 379
 380 /*
 381  * Send a SMB request and set the callback function in the mid to handle
 382  * the result. Caller is responsible for dealing with timeouts.
 383  */
 384 int
 385 cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
 386                 unsigned int nvec, mid_receive_t *receive,
 387                 mid_callback_t *callback, void *cbdata, bool ignore_pend)
 388 {
 389         int rc;
 390         struct mid_q_entry *mid;
 391
 392         rc = wait_for_free_request(server, ignore_pend ? CIFS_ASYNC_OP : 0);
 393         if (rc)
 394                 return rc;
 395
 396         mutex_lock(&server->srv_mutex);
 397         rc = cifs_setup_async_request(server, iov, nvec, &mid);
 398         if (rc) {
 399                 mutex_unlock(&server->srv_mutex);
 400                 add_credits(server, 1);
 401                 wake_up(&server->request_q);
 402                 return rc;
 403         }
 404
 405         mid->receive = receive;
 406         mid->callback = callback;
 407         mid->callback_data = cbdata;
 408         mid->mid_state = MID_REQUEST_SUBMITTED;
 409
 410         cifs_in_send_inc(server);
 411         rc = smb_sendv(server, iov, nvec);
 412         cifs_in_send_dec(server);
 413         cifs_save_when_sent(mid);
 414         mutex_unlock(&server->srv_mutex);
 415
 416         if (rc)
 417                 goto out_err;
 418
 419         return rc;
 420 out_err:
 421         delete_mid(mid);
 422         add_credits(server, 1);
 423         wake_up(&server->request_q);
 424         return rc;
 425 }
 426
 427 /*
 428  *
 429  * Send an SMB Request.  No response info (other than return code)
 430  * needs to be parsed.
 431  *
 432  * flags indicate the type of request buffer and how long to wait
 433  * and whether to log NT STATUS code (error) before mapping it to POSIX error
 434  *
 435  */
 436 int
 437 SendReceiveNoRsp(const unsigned int xid, struct cifs_ses *ses,
 438                  char *in_buf, int flags)
 439 {
 440         int rc;
 441         struct kvec iov[1];
 442         int resp_buf_type;
 443
 444         iov[0].iov_base = in_buf;
 445         iov[0].iov_len = get_rfc1002_length(in_buf) + 4;
 446         flags |= CIFS_NO_RESP;
 447         rc = SendReceive2(xid, ses, iov, 1, &resp_buf_type, flags);
 448         cFYI(DBG2, "SendRcvNoRsp flags %d rc %d", flags, rc);
 449
 450         return rc;
 451 }
 452
 453 static int
 454 cifs_sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
 455 {
 456         int rc = 0;
 457
 458         cFYI(1, "%s: cmd=%d mid=%llu state=%d", __func__,
 459              le16_to_cpu(mid->command), mid->mid, mid->mid_state);
 460
 461         spin_lock(&GlobalMid_Lock);
 462         switch (mid->mid_state) {
 463         case MID_RESPONSE_RECEIVED:
 464                 spin_unlock(&GlobalMid_Lock);
 465                 return rc;
 466         case MID_RETRY_NEEDED:
 467                 rc = -EAGAIN;
 468                 break;
 469         case MID_RESPONSE_MALFORMED:
 470                 rc = -EIO;
 471                 break;
 472         case MID_SHUTDOWN:
 473                 rc = -EHOSTDOWN;
 474                 break;
 475         default:
 476                 list_del_init(&mid->qhead);
 477                 cERROR(1, "%s: invalid mid state mid=%llu state=%d", __func__,
 478                        mid->mid, mid->mid_state);
 479                 rc = -EIO;
 480         }
 481         spin_unlock(&GlobalMid_Lock);
 482
 483         DeleteMidQEntry(mid);
 484         return rc;
 485 }
 486
 487 static inline int
 488 send_cancel(struct TCP_Server_Info *server, void *buf, struct mid_q_entry *mid)
 489 {
 490         return server->ops->send_cancel ?
 491                                 server->ops->send_cancel(server, buf, mid) : 0;
 492 }
 493
 494 int
 495 cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 496                    bool log_error)
 497 {
 498         unsigned int len = get_rfc1002_length(mid->resp_buf) + 4;
 499
 500         dump_smb(mid->resp_buf, min_t(u32, 92, len));
 501
 502         /* convert the length into a more usable form */
 503         if (server->sec_mode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
 504                 struct kvec iov;
 505
 506                 iov.iov_base = mid->resp_buf;
 507                 iov.iov_len = len;
 508                 /* FIXME: add code to kill session */
 509                 if (cifs_verify_signature(&iov, 1, server,
 510                                           mid->sequence_number + 1) != 0)
 511                         cERROR(1, "Unexpected SMB signature");
 512         }
 513
 514         /* BB special case reconnect tid and uid here? */
 515         return map_smb_to_linux_error(mid->resp_buf, log_error);
 516 }
 517
 518 int
 519 cifs_setup_request(struct cifs_ses *ses, struct kvec *iov,
 520                    unsigned int nvec, struct mid_q_entry **ret_mid)
 521 {
 522         int rc;
 523         struct smb_hdr *hdr = (struct smb_hdr *)iov[0].iov_base;
 524         struct mid_q_entry *mid;
 525
 526         rc = allocate_mid(ses, hdr, &mid);
 527         if (rc)
 528                 return rc;
 529         rc = cifs_sign_smb2(iov, nvec, ses->server, &mid->sequence_number);
 530         if (rc)
 531                 delete_mid(mid);
 532         *ret_mid = mid;
 533         return rc;
 534 }
 535
 536 int
 537 SendReceive2(const unsigned int xid, struct cifs_ses *ses,
 538              struct kvec *iov, int n_vec, int *pRespBufType /* ret */,
 539              const int flags)
 540 {
 541         int rc = 0;
 542         int long_op;
 543         struct mid_q_entry *midQ;
 544         char *buf = iov[0].iov_base;
 545
 546         long_op = flags & CIFS_TIMEOUT_MASK;
 547
 548         *pRespBufType = CIFS_NO_BUFFER;  /* no response buf yet */
 549
 550         if ((ses == NULL) || (ses->server == NULL)) {
 551                 cifs_small_buf_release(buf);
 552                 cERROR(1, "Null session");
 553                 return -EIO;
 554         }
 555
 556         if (ses->server->tcpStatus == CifsExiting) {
 557                 cifs_small_buf_release(buf);
 558                 return -ENOENT;
 559         }
 560
 561         /*
 562          * Ensure that we do not send more than 50 overlapping requests
 563          * to the same server. We may make this configurable later or
 564          * use ses->maxReq.
 565          */
 566
 567         rc = wait_for_free_request(ses->server, long_op);
 568         if (rc) {
 569                 cifs_small_buf_release(buf);
 570                 return rc;
 571         }
 572
 573         /*
 574          * Make sure that we sign in the same order that we send on this socket
 575          * and avoid races inside tcp sendmsg code that could cause corruption
 576          * of smb data.
 577          */
 578
 579         mutex_lock(&ses->server->srv_mutex);
 580
 581         rc = ses->server->ops->setup_request(ses, iov, n_vec, &midQ);
 582         if (rc) {
 583                 mutex_unlock(&ses->server->srv_mutex);
 584                 cifs_small_buf_release(buf);
 585                 /* Update # of requests on wire to server */
 586                 add_credits(ses->server, 1);
 587                 return rc;
 588         }
 589
 590         midQ->mid_state = MID_REQUEST_SUBMITTED;
 591         cifs_in_send_inc(ses->server);
 592         rc = smb_sendv(ses->server, iov, n_vec);
 593         cifs_in_send_dec(ses->server);
 594         cifs_save_when_sent(midQ);
 595
 596         mutex_unlock(&ses->server->srv_mutex);
 597
 598         if (rc < 0) {
 599                 cifs_small_buf_release(buf);
 600                 goto out;
 601         }
 602
 603         if (long_op == CIFS_ASYNC_OP) {
 604                 cifs_small_buf_release(buf);
 605                 goto out;
 606         }
 607
 608         rc = wait_for_response(ses->server, midQ);
 609         if (rc != 0) {
 610                 send_cancel(ses->server, buf, midQ);
 611                 spin_lock(&GlobalMid_Lock);
 612                 if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
 613                         midQ->callback = DeleteMidQEntry;
 614                         spin_unlock(&GlobalMid_Lock);
 615                         cifs_small_buf_release(buf);
 616                         add_credits(ses->server, 1);
 617                         return rc;
 618                 }
 619                 spin_unlock(&GlobalMid_Lock);
 620         }
 621
 622         cifs_small_buf_release(buf);
 623
 624         rc = cifs_sync_mid_result(midQ, ses->server);
 625         if (rc != 0) {
 626                 add_credits(ses->server, 1);
 627                 return rc;
 628         }
 629
 630         if (!midQ->resp_buf || midQ->mid_state != MID_RESPONSE_RECEIVED) {
 631                 rc = -EIO;
 632                 cFYI(1, "Bad MID state?");
 633                 goto out;
 634         }
 635
 636         buf = (char *)midQ->resp_buf;
 637         iov[0].iov_base = buf;
 638         iov[0].iov_len = get_rfc1002_length(buf) + 4;
 639         if (midQ->large_buf)
 640                 *pRespBufType = CIFS_LARGE_BUFFER;
 641         else
 642                 *pRespBufType = CIFS_SMALL_BUFFER;
 643
 644         rc = ses->server->ops->check_receive(midQ, ses->server,
 645                                              flags & CIFS_LOG_ERROR);
 646
 647         /* mark it so buf will not be freed by delete_mid */
 648         if ((flags & CIFS_NO_RESP) == 0)
 649                 midQ->resp_buf = NULL;
 650 out:
 651         delete_mid(midQ);
 652         add_credits(ses->server, 1);
 653
 654         return rc;
 655 }
 656
 657 int
 658 SendReceive(const unsigned int xid, struct cifs_ses *ses,
 659             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
 660             int *pbytes_returned, const int long_op)
 661 {
 662         int rc = 0;
 663         struct mid_q_entry *midQ;
 664
 665         if (ses == NULL) {
 666                 cERROR(1, "Null smb session");
 667                 return -EIO;
 668         }
 669         if (ses->server == NULL) {
 670                 cERROR(1, "Null tcp session");
 671                 return -EIO;
 672         }
 673
 674         if (ses->server->tcpStatus == CifsExiting)
 675                 return -ENOENT;
 676
 677         /* Ensure that we do not send more than 50 overlapping requests
 678            to the same server. We may make this configurable later or
 679            use ses->maxReq */
 680
 681         if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
 682                         MAX_CIFS_HDR_SIZE - 4) {
 683                 cERROR(1, "Illegal length, greater than maximum frame, %d",
 684                            be32_to_cpu(in_buf->smb_buf_length));
 685                 return -EIO;
 686         }
 687
 688         rc = wait_for_free_request(ses->server, long_op);
 689         if (rc)
 690                 return rc;
 691
 692         /* make sure that we sign in the same order that we send on this socket
 693            and avoid races inside tcp sendmsg code that could cause corruption
 694            of smb data */
 695
 696         mutex_lock(&ses->server->srv_mutex);
 697
 698         rc = allocate_mid(ses, in_buf, &midQ);
 699         if (rc) {
 700                 mutex_unlock(&ses->server->srv_mutex);
 701                 /* Update # of requests on wire to server */
 702                 add_credits(ses->server, 1);
 703                 return rc;
 704         }
 705
 706         rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
 707         if (rc) {
 708                 mutex_unlock(&ses->server->srv_mutex);
 709                 goto out;
 710         }
 711
 712         midQ->mid_state = MID_REQUEST_SUBMITTED;
 713
 714         cifs_in_send_inc(ses->server);
 715         rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
 716         cifs_in_send_dec(ses->server);
 717         cifs_save_when_sent(midQ);
 718         mutex_unlock(&ses->server->srv_mutex);
 719
 720         if (rc < 0)
 721                 goto out;
 722
 723         if (long_op == CIFS_ASYNC_OP)
 724                 goto out;
 725
 726         rc = wait_for_response(ses->server, midQ);
 727         if (rc != 0) {
 728                 send_cancel(ses->server, in_buf, midQ);
 729                 spin_lock(&GlobalMid_Lock);
 730                 if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
 731                         /* no longer considered to be "in-flight" */
 732                         midQ->callback = DeleteMidQEntry;
 733                         spin_unlock(&GlobalMid_Lock);
 734                         add_credits(ses->server, 1);
 735                         return rc;
 736                 }
 737                 spin_unlock(&GlobalMid_Lock);
 738         }
 739
 740         rc = cifs_sync_mid_result(midQ, ses->server);
 741         if (rc != 0) {
 742                 add_credits(ses->server, 1);
 743                 return rc;
 744         }
 745
 746         if (!midQ->resp_buf || !out_buf ||
 747             midQ->mid_state != MID_RESPONSE_RECEIVED) {
 748                 rc = -EIO;
 749                 cERROR(1, "Bad MID state?");
 750                 goto out;
 751         }
 752
 753         *pbytes_returned = get_rfc1002_length(midQ->resp_buf);
 754         memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
 755         rc = cifs_check_receive(midQ, ses->server, 0);
 756 out:
 757         delete_mid(midQ);
 758         add_credits(ses->server, 1);
 759
 760         return rc;
 761 }
 762
 763 /* We send a LOCKINGX_CANCEL_LOCK to cause the Windows
 764    blocking lock to return. */
 765
 766 static int
 767 send_lock_cancel(const unsigned int xid, struct cifs_tcon *tcon,
 768                         struct smb_hdr *in_buf,
 769                         struct smb_hdr *out_buf)
 770 {
 771         int bytes_returned;
 772         struct cifs_ses *ses = tcon->ses;
 773         LOCK_REQ *pSMB = (LOCK_REQ *)in_buf;
 774
 775         /* We just modify the current in_buf to change
 776            the type of lock from LOCKING_ANDX_SHARED_LOCK
 777            or LOCKING_ANDX_EXCLUSIVE_LOCK to
 778            LOCKING_ANDX_CANCEL_LOCK. */
 779
 780         pSMB->LockType = LOCKING_ANDX_CANCEL_LOCK|LOCKING_ANDX_LARGE_FILES;
 781         pSMB->Timeout = 0;
 782         pSMB->hdr.Mid = get_next_mid(ses->server);
 783
 784         return SendReceive(xid, ses, in_buf, out_buf,
 785                         &bytes_returned, 0);
 786 }
 787
 788 int
 789 SendReceiveBlockingLock(const unsigned int xid, struct cifs_tcon *tcon,
 790             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
 791             int *pbytes_returned)
 792 {
 793         int rc = 0;
 794         int rstart = 0;
 795         struct mid_q_entry *midQ;
 796         struct cifs_ses *ses;
 797
 798         if (tcon == NULL || tcon->ses == NULL) {
 799                 cERROR(1, "Null smb session");
 800                 return -EIO;
 801         }
 802         ses = tcon->ses;
 803
 804         if (ses->server == NULL) {
 805                 cERROR(1, "Null tcp session");
 806                 return -EIO;
 807         }
 808
 809         if (ses->server->tcpStatus == CifsExiting)
 810                 return -ENOENT;
 811
 812         /* Ensure that we do not send more than 50 overlapping requests
 813            to the same server. We may make this configurable later or
 814            use ses->maxReq */
 815
 816         if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
 817                         MAX_CIFS_HDR_SIZE - 4) {
 818                 cERROR(1, "Illegal length, greater than maximum frame, %d",
 819                            be32_to_cpu(in_buf->smb_buf_length));
 820                 return -EIO;
 821         }
 822
 823         rc = wait_for_free_request(ses->server, CIFS_BLOCKING_OP);
 824         if (rc)
 825                 return rc;
 826
 827         /* make sure that we sign in the same order that we send on this socket
 828            and avoid races inside tcp sendmsg code that could cause corruption
 829            of smb data */
 830
 831         mutex_lock(&ses->server->srv_mutex);
 832
 833         rc = allocate_mid(ses, in_buf, &midQ);
 834         if (rc) {
 835                 mutex_unlock(&ses->server->srv_mutex);
 836                 return rc;
 837         }
 838
 839         rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
 840         if (rc) {
 841                 delete_mid(midQ);
 842                 mutex_unlock(&ses->server->srv_mutex);
 843                 return rc;
 844         }
 845
 846         midQ->mid_state = MID_REQUEST_SUBMITTED;
 847         cifs_in_send_inc(ses->server);
 848         rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
 849         cifs_in_send_dec(ses->server);
 850         cifs_save_when_sent(midQ);
 851         mutex_unlock(&ses->server->srv_mutex);
 852
 853         if (rc < 0) {
 854                 delete_mid(midQ);
 855                 return rc;
 856         }
 857
 858         /* Wait for a reply - allow signals to interrupt. */
 859         rc = wait_event_interruptible(ses->server->response_q,
 860                 (!(midQ->mid_state == MID_REQUEST_SUBMITTED)) ||
 861                 ((ses->server->tcpStatus != CifsGood) &&
 862                  (ses->server->tcpStatus != CifsNew)));
 863
 864         /* Were we interrupted by a signal ? */
 865         if ((rc == -ERESTARTSYS) &&
 866                 (midQ->mid_state == MID_REQUEST_SUBMITTED) &&
 867                 ((ses->server->tcpStatus == CifsGood) ||
 868                  (ses->server->tcpStatus == CifsNew))) {
 869
 870                 if (in_buf->Command == SMB_COM_TRANSACTION2) {
 871                         /* POSIX lock. We send a NT_CANCEL SMB to cause the
 872                            blocking lock to return. */
 873                         rc = send_cancel(ses->server, in_buf, midQ);
 874                         if (rc) {
 875                                 delete_mid(midQ);
 876                                 return rc;
 877                         }
 878                 } else {
 879                         /* Windows lock. We send a LOCKINGX_CANCEL_LOCK
 880                            to cause the blocking lock to return. */
 881
 882                         rc = send_lock_cancel(xid, tcon, in_buf, out_buf);
 883
 884                         /* If we get -ENOLCK back the lock may have
 885                            already been removed. Don't exit in this case. */
 886                         if (rc && rc != -ENOLCK) {
 887                                 delete_mid(midQ);
 888                                 return rc;
 889                         }
 890                 }
 891
 892                 rc = wait_for_response(ses->server, midQ);
 893                 if (rc) {
 894                         send_cancel(ses->server, in_buf, midQ);
 895                         spin_lock(&GlobalMid_Lock);
 896                         if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
 897                                 /* no longer considered to be "in-flight" */
 898                                 midQ->callback = DeleteMidQEntry;
 899                                 spin_unlock(&GlobalMid_Lock);
 900                                 return rc;
 901                         }
 902                         spin_unlock(&GlobalMid_Lock);
 903                 }
 904
 905                 /* We got the response - restart system call. */
 906                 rstart = 1;
 907         }
 908
 909         rc = cifs_sync_mid_result(midQ, ses->server);
 910         if (rc != 0)
 911                 return rc;
 912
 913         /* rcvd frame is ok */
 914         if (out_buf == NULL || midQ->mid_state != MID_RESPONSE_RECEIVED) {
 915                 rc = -EIO;
 916                 cERROR(1, "Bad MID state?");
 917                 goto out;
 918         }
 919
 920         *pbytes_returned = get_rfc1002_length(midQ->resp_buf);
 921         memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
 922         rc = cifs_check_receive(midQ, ses->server, 0);
 923 out:
 924         delete_mid(midQ);
 925         if (rstart && rc == -EACCES)
 926                 return -ERESTARTSYS;
 927         return rc;
 928 }