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         rc = cifs_sign_smb2(iov, nvec, server, &mid->sequence_number);
 369         if (rc) {
 370                 DeleteMidQEntry(mid);
 371                 return rc;
 372         }
 373
 374         *ret_mid = mid;
 375         return 0;
 376 }
 377
 378 /*
 379  * Send a SMB request and set the callback function in the mid to handle
 380  * the result. Caller is responsible for dealing with timeouts.
 381  */
 382 int
 383 cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
 384                 unsigned int nvec, mid_receive_t *receive,
 385                 mid_callback_t *callback, void *cbdata, bool ignore_pend)
 386 {
 387         int rc;
 388         struct mid_q_entry *mid;
 389
 390         rc = wait_for_free_request(server, ignore_pend ? CIFS_ASYNC_OP : 0);
 391         if (rc)
 392                 return rc;
 393
 394         mutex_lock(&server->srv_mutex);
 395         rc = cifs_setup_async_request(server, iov, nvec, &mid);
 396         if (rc) {
 397                 mutex_unlock(&server->srv_mutex);
 398                 add_credits(server, 1);
 399                 wake_up(&server->request_q);
 400                 return rc;
 401         }
 402
 403         mid->receive = receive;
 404         mid->callback = callback;
 405         mid->callback_data = cbdata;
 406         mid->mid_state = MID_REQUEST_SUBMITTED;
 407
 408         /* put it on the pending_mid_q */
 409         spin_lock(&GlobalMid_Lock);
 410         list_add_tail(&mid->qhead, &server->pending_mid_q);
 411         spin_unlock(&GlobalMid_Lock);
 412
 413
 414         cifs_in_send_inc(server);
 415         rc = smb_sendv(server, iov, nvec);
 416         cifs_in_send_dec(server);
 417         cifs_save_when_sent(mid);
 418         mutex_unlock(&server->srv_mutex);
 419
 420         if (rc == 0)
 421                 return 0;
 422
 423         delete_mid(mid);
 424         add_credits(server, 1);
 425         wake_up(&server->request_q);
 426         return rc;
 427 }
 428
 429 /*
 430  *
 431  * Send an SMB Request.  No response info (other than return code)
 432  * needs to be parsed.
 433  *
 434  * flags indicate the type of request buffer and how long to wait
 435  * and whether to log NT STATUS code (error) before mapping it to POSIX error
 436  *
 437  */
 438 int
 439 SendReceiveNoRsp(const unsigned int xid, struct cifs_ses *ses,
 440                  char *in_buf, int flags)
 441 {
 442         int rc;
 443         struct kvec iov[1];
 444         int resp_buf_type;
 445
 446         iov[0].iov_base = in_buf;
 447         iov[0].iov_len = get_rfc1002_length(in_buf) + 4;
 448         flags |= CIFS_NO_RESP;
 449         rc = SendReceive2(xid, ses, iov, 1, &resp_buf_type, flags);
 450         cFYI(DBG2, "SendRcvNoRsp flags %d rc %d", flags, rc);
 451
 452         return rc;
 453 }
 454
 455 static int
 456 cifs_sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
 457 {
 458         int rc = 0;
 459
 460         cFYI(1, "%s: cmd=%d mid=%llu state=%d", __func__,
 461              le16_to_cpu(mid->command), mid->mid, mid->mid_state);
 462
 463         spin_lock(&GlobalMid_Lock);
 464         switch (mid->mid_state) {
 465         case MID_RESPONSE_RECEIVED:
 466                 spin_unlock(&GlobalMid_Lock);
 467                 return rc;
 468         case MID_RETRY_NEEDED:
 469                 rc = -EAGAIN;
 470                 break;
 471         case MID_RESPONSE_MALFORMED:
 472                 rc = -EIO;
 473                 break;
 474         case MID_SHUTDOWN:
 475                 rc = -EHOSTDOWN;
 476                 break;
 477         default:
 478                 list_del_init(&mid->qhead);
 479                 cERROR(1, "%s: invalid mid state mid=%llu state=%d", __func__,
 480                        mid->mid, mid->mid_state);
 481                 rc = -EIO;
 482         }
 483         spin_unlock(&GlobalMid_Lock);
 484
 485         DeleteMidQEntry(mid);
 486         return rc;
 487 }
 488
 489 static inline int
 490 send_cancel(struct TCP_Server_Info *server, void *buf, struct mid_q_entry *mid)
 491 {
 492         return server->ops->send_cancel ?
 493                                 server->ops->send_cancel(server, buf, mid) : 0;
 494 }
 495
 496 int
 497 cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 498                    bool log_error)
 499 {
 500         unsigned int len = get_rfc1002_length(mid->resp_buf) + 4;
 501
 502         dump_smb(mid->resp_buf, min_t(u32, 92, len));
 503
 504         /* convert the length into a more usable form */
 505         if (server->sec_mode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
 506                 struct kvec iov;
 507
 508                 iov.iov_base = mid->resp_buf;
 509                 iov.iov_len = len;
 510                 /* FIXME: add code to kill session */
 511                 if (cifs_verify_signature(&iov, 1, server,
 512                                           mid->sequence_number + 1) != 0)
 513                         cERROR(1, "Unexpected SMB signature");
 514         }
 515
 516         /* BB special case reconnect tid and uid here? */
 517         return map_smb_to_linux_error(mid->resp_buf, log_error);
 518 }
 519
 520 int
 521 cifs_setup_request(struct cifs_ses *ses, struct kvec *iov,
 522                    unsigned int nvec, struct mid_q_entry **ret_mid)
 523 {
 524         int rc;
 525         struct smb_hdr *hdr = (struct smb_hdr *)iov[0].iov_base;
 526         struct mid_q_entry *mid;
 527
 528         rc = allocate_mid(ses, hdr, &mid);
 529         if (rc)
 530                 return rc;
 531         rc = cifs_sign_smb2(iov, nvec, ses->server, &mid->sequence_number);
 532         if (rc)
 533                 delete_mid(mid);
 534         *ret_mid = mid;
 535         return rc;
 536 }
 537
 538 int
 539 SendReceive2(const unsigned int xid, struct cifs_ses *ses,
 540              struct kvec *iov, int n_vec, int *pRespBufType /* ret */,
 541              const int flags)
 542 {
 543         int rc = 0;
 544         int long_op;
 545         struct mid_q_entry *midQ;
 546         char *buf = iov[0].iov_base;
 547
 548         long_op = flags & CIFS_TIMEOUT_MASK;
 549
 550         *pRespBufType = CIFS_NO_BUFFER;  /* no response buf yet */
 551
 552         if ((ses == NULL) || (ses->server == NULL)) {
 553                 cifs_small_buf_release(buf);
 554                 cERROR(1, "Null session");
 555                 return -EIO;
 556         }
 557
 558         if (ses->server->tcpStatus == CifsExiting) {
 559                 cifs_small_buf_release(buf);
 560                 return -ENOENT;
 561         }
 562
 563         /*
 564          * Ensure that we do not send more than 50 overlapping requests
 565          * to the same server. We may make this configurable later or
 566          * use ses->maxReq.
 567          */
 568
 569         rc = wait_for_free_request(ses->server, long_op);
 570         if (rc) {
 571                 cifs_small_buf_release(buf);
 572                 return rc;
 573         }
 574
 575         /*
 576          * Make sure that we sign in the same order that we send on this socket
 577          * and avoid races inside tcp sendmsg code that could cause corruption
 578          * of smb data.
 579          */
 580
 581         mutex_lock(&ses->server->srv_mutex);
 582
 583         rc = ses->server->ops->setup_request(ses, iov, n_vec, &midQ);
 584         if (rc) {
 585                 mutex_unlock(&ses->server->srv_mutex);
 586                 cifs_small_buf_release(buf);
 587                 /* Update # of requests on wire to server */
 588                 add_credits(ses->server, 1);
 589                 return rc;
 590         }
 591
 592         midQ->mid_state = MID_REQUEST_SUBMITTED;
 593         cifs_in_send_inc(ses->server);
 594         rc = smb_sendv(ses->server, iov, n_vec);
 595         cifs_in_send_dec(ses->server);
 596         cifs_save_when_sent(midQ);
 597
 598         mutex_unlock(&ses->server->srv_mutex);
 599
 600         if (rc < 0) {
 601                 cifs_small_buf_release(buf);
 602                 goto out;
 603         }
 604
 605         if (long_op == CIFS_ASYNC_OP) {
 606                 cifs_small_buf_release(buf);
 607                 goto out;
 608         }
 609
 610         rc = wait_for_response(ses->server, midQ);
 611         if (rc != 0) {
 612                 send_cancel(ses->server, buf, midQ);
 613                 spin_lock(&GlobalMid_Lock);
 614                 if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
 615                         midQ->callback = DeleteMidQEntry;
 616                         spin_unlock(&GlobalMid_Lock);
 617                         cifs_small_buf_release(buf);
 618                         add_credits(ses->server, 1);
 619                         return rc;
 620                 }
 621                 spin_unlock(&GlobalMid_Lock);
 622         }
 623
 624         cifs_small_buf_release(buf);
 625
 626         rc = cifs_sync_mid_result(midQ, ses->server);
 627         if (rc != 0) {
 628                 add_credits(ses->server, 1);
 629                 return rc;
 630         }
 631
 632         if (!midQ->resp_buf || midQ->mid_state != MID_RESPONSE_RECEIVED) {
 633                 rc = -EIO;
 634                 cFYI(1, "Bad MID state?");
 635                 goto out;
 636         }
 637
 638         buf = (char *)midQ->resp_buf;
 639         iov[0].iov_base = buf;
 640         iov[0].iov_len = get_rfc1002_length(buf) + 4;
 641         if (midQ->large_buf)
 642                 *pRespBufType = CIFS_LARGE_BUFFER;
 643         else
 644                 *pRespBufType = CIFS_SMALL_BUFFER;
 645
 646         rc = ses->server->ops->check_receive(midQ, ses->server,
 647                                              flags & CIFS_LOG_ERROR);
 648
 649         /* mark it so buf will not be freed by delete_mid */
 650         if ((flags & CIFS_NO_RESP) == 0)
 651                 midQ->resp_buf = NULL;
 652 out:
 653         delete_mid(midQ);
 654         add_credits(ses->server, 1);
 655
 656         return rc;
 657 }
 658
 659 int
 660 SendReceive(const unsigned int xid, struct cifs_ses *ses,
 661             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
 662             int *pbytes_returned, const int long_op)
 663 {
 664         int rc = 0;
 665         struct mid_q_entry *midQ;
 666
 667         if (ses == NULL) {
 668                 cERROR(1, "Null smb session");
 669                 return -EIO;
 670         }
 671         if (ses->server == NULL) {
 672                 cERROR(1, "Null tcp session");
 673                 return -EIO;
 674         }
 675
 676         if (ses->server->tcpStatus == CifsExiting)
 677                 return -ENOENT;
 678
 679         /* Ensure that we do not send more than 50 overlapping requests
 680            to the same server. We may make this configurable later or
 681            use ses->maxReq */
 682
 683         if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
 684                         MAX_CIFS_HDR_SIZE - 4) {
 685                 cERROR(1, "Illegal length, greater than maximum frame, %d",
 686                            be32_to_cpu(in_buf->smb_buf_length));
 687                 return -EIO;
 688         }
 689
 690         rc = wait_for_free_request(ses->server, long_op);
 691         if (rc)
 692                 return rc;
 693
 694         /* make sure that we sign in the same order that we send on this socket
 695            and avoid races inside tcp sendmsg code that could cause corruption
 696            of smb data */
 697
 698         mutex_lock(&ses->server->srv_mutex);
 699
 700         rc = allocate_mid(ses, in_buf, &midQ);
 701         if (rc) {
 702                 mutex_unlock(&ses->server->srv_mutex);
 703                 /* Update # of requests on wire to server */
 704                 add_credits(ses->server, 1);
 705                 return rc;
 706         }
 707
 708         rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
 709         if (rc) {
 710                 mutex_unlock(&ses->server->srv_mutex);
 711                 goto out;
 712         }
 713
 714         midQ->mid_state = MID_REQUEST_SUBMITTED;
 715
 716         cifs_in_send_inc(ses->server);
 717         rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
 718         cifs_in_send_dec(ses->server);
 719         cifs_save_when_sent(midQ);
 720         mutex_unlock(&ses->server->srv_mutex);
 721
 722         if (rc < 0)
 723                 goto out;
 724
 725         if (long_op == CIFS_ASYNC_OP)
 726                 goto out;
 727
 728         rc = wait_for_response(ses->server, midQ);
 729         if (rc != 0) {
 730                 send_cancel(ses->server, in_buf, midQ);
 731                 spin_lock(&GlobalMid_Lock);
 732                 if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
 733                         /* no longer considered to be "in-flight" */
 734                         midQ->callback = DeleteMidQEntry;
 735                         spin_unlock(&GlobalMid_Lock);
 736                         add_credits(ses->server, 1);
 737                         return rc;
 738                 }
 739                 spin_unlock(&GlobalMid_Lock);
 740         }
 741
 742         rc = cifs_sync_mid_result(midQ, ses->server);
 743         if (rc != 0) {
 744                 add_credits(ses->server, 1);
 745                 return rc;
 746         }
 747
 748         if (!midQ->resp_buf || !out_buf ||
 749             midQ->mid_state != MID_RESPONSE_RECEIVED) {
 750                 rc = -EIO;
 751                 cERROR(1, "Bad MID state?");
 752                 goto out;
 753         }
 754
 755         *pbytes_returned = get_rfc1002_length(midQ->resp_buf);
 756         memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
 757         rc = cifs_check_receive(midQ, ses->server, 0);
 758 out:
 759         delete_mid(midQ);
 760         add_credits(ses->server, 1);
 761
 762         return rc;
 763 }
 764
 765 /* We send a LOCKINGX_CANCEL_LOCK to cause the Windows
 766    blocking lock to return. */
 767
 768 static int
 769 send_lock_cancel(const unsigned int xid, struct cifs_tcon *tcon,
 770                         struct smb_hdr *in_buf,
 771                         struct smb_hdr *out_buf)
 772 {
 773         int bytes_returned;
 774         struct cifs_ses *ses = tcon->ses;
 775         LOCK_REQ *pSMB = (LOCK_REQ *)in_buf;
 776
 777         /* We just modify the current in_buf to change
 778            the type of lock from LOCKING_ANDX_SHARED_LOCK
 779            or LOCKING_ANDX_EXCLUSIVE_LOCK to
 780            LOCKING_ANDX_CANCEL_LOCK. */
 781
 782         pSMB->LockType = LOCKING_ANDX_CANCEL_LOCK|LOCKING_ANDX_LARGE_FILES;
 783         pSMB->Timeout = 0;
 784         pSMB->hdr.Mid = get_next_mid(ses->server);
 785
 786         return SendReceive(xid, ses, in_buf, out_buf,
 787                         &bytes_returned, 0);
 788 }
 789
 790 int
 791 SendReceiveBlockingLock(const unsigned int xid, struct cifs_tcon *tcon,
 792             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
 793             int *pbytes_returned)
 794 {
 795         int rc = 0;
 796         int rstart = 0;
 797         struct mid_q_entry *midQ;
 798         struct cifs_ses *ses;
 799
 800         if (tcon == NULL || tcon->ses == NULL) {
 801                 cERROR(1, "Null smb session");
 802                 return -EIO;
 803         }
 804         ses = tcon->ses;
 805
 806         if (ses->server == NULL) {
 807                 cERROR(1, "Null tcp session");
 808                 return -EIO;
 809         }
 810
 811         if (ses->server->tcpStatus == CifsExiting)
 812                 return -ENOENT;
 813
 814         /* Ensure that we do not send more than 50 overlapping requests
 815            to the same server. We may make this configurable later or
 816            use ses->maxReq */
 817
 818         if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
 819                         MAX_CIFS_HDR_SIZE - 4) {
 820                 cERROR(1, "Illegal length, greater than maximum frame, %d",
 821                            be32_to_cpu(in_buf->smb_buf_length));
 822                 return -EIO;
 823         }
 824
 825         rc = wait_for_free_request(ses->server, CIFS_BLOCKING_OP);
 826         if (rc)
 827                 return rc;
 828
 829         /* make sure that we sign in the same order that we send on this socket
 830            and avoid races inside tcp sendmsg code that could cause corruption
 831            of smb data */
 832
 833         mutex_lock(&ses->server->srv_mutex);
 834
 835         rc = allocate_mid(ses, in_buf, &midQ);
 836         if (rc) {
 837                 mutex_unlock(&ses->server->srv_mutex);
 838                 return rc;
 839         }
 840
 841         rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
 842         if (rc) {
 843                 delete_mid(midQ);
 844                 mutex_unlock(&ses->server->srv_mutex);
 845                 return rc;
 846         }
 847
 848         midQ->mid_state = MID_REQUEST_SUBMITTED;
 849         cifs_in_send_inc(ses->server);
 850         rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
 851         cifs_in_send_dec(ses->server);
 852         cifs_save_when_sent(midQ);
 853         mutex_unlock(&ses->server->srv_mutex);
 854
 855         if (rc < 0) {
 856                 delete_mid(midQ);
 857                 return rc;
 858         }
 859
 860         /* Wait for a reply - allow signals to interrupt. */
 861         rc = wait_event_interruptible(ses->server->response_q,
 862                 (!(midQ->mid_state == MID_REQUEST_SUBMITTED)) ||
 863                 ((ses->server->tcpStatus != CifsGood) &&
 864                  (ses->server->tcpStatus != CifsNew)));
 865
 866         /* Were we interrupted by a signal ? */
 867         if ((rc == -ERESTARTSYS) &&
 868                 (midQ->mid_state == MID_REQUEST_SUBMITTED) &&
 869                 ((ses->server->tcpStatus == CifsGood) ||
 870                  (ses->server->tcpStatus == CifsNew))) {
 871
 872                 if (in_buf->Command == SMB_COM_TRANSACTION2) {
 873                         /* POSIX lock. We send a NT_CANCEL SMB to cause the
 874                            blocking lock to return. */
 875                         rc = send_cancel(ses->server, in_buf, midQ);
 876                         if (rc) {
 877                                 delete_mid(midQ);
 878                                 return rc;
 879                         }
 880                 } else {
 881                         /* Windows lock. We send a LOCKINGX_CANCEL_LOCK
 882                            to cause the blocking lock to return. */
 883
 884                         rc = send_lock_cancel(xid, tcon, in_buf, out_buf);
 885
 886                         /* If we get -ENOLCK back the lock may have
 887                            already been removed. Don't exit in this case. */
 888                         if (rc && rc != -ENOLCK) {
 889                                 delete_mid(midQ);
 890                                 return rc;
 891                         }
 892                 }
 893
 894                 rc = wait_for_response(ses->server, midQ);
 895                 if (rc) {
 896                         send_cancel(ses->server, in_buf, midQ);
 897                         spin_lock(&GlobalMid_Lock);
 898                         if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
 899                                 /* no longer considered to be "in-flight" */
 900                                 midQ->callback = DeleteMidQEntry;
 901                                 spin_unlock(&GlobalMid_Lock);
 902                                 return rc;
 903                         }
 904                         spin_unlock(&GlobalMid_Lock);
 905                 }
 906
 907                 /* We got the response - restart system call. */
 908                 rstart = 1;
 909         }
 910
 911         rc = cifs_sync_mid_result(midQ, ses->server);
 912         if (rc != 0)
 913                 return rc;
 914
 915         /* rcvd frame is ok */
 916         if (out_buf == NULL || midQ->mid_state != MID_RESPONSE_RECEIVED) {
 917                 rc = -EIO;
 918                 cERROR(1, "Bad MID state?");
 919                 goto out;
 920         }
 921
 922         *pbytes_returned = get_rfc1002_length(midQ->resp_buf);
 923         memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
 924         rc = cifs_check_receive(midQ, ses->server, 0);
 925 out:
 926         delete_mid(midQ);
 927         if (rstart && rc == -EACCES)
 928                 return -ERESTARTSYS;
 929         return rc;
 930 }