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 void
  39 cifs_wake_up_task(struct mid_q_entry *mid)
  40 {
  41         wake_up_process(mid->callback_data);
  42 }
  43
  44 struct mid_q_entry *
  45 AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
  46 {
  47         struct mid_q_entry *temp;
  48
  49         if (server == NULL) {
  50                 cERROR(1, "Null TCP session in AllocMidQEntry");
  51                 return NULL;
  52         }
  53
  54         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
  55         if (temp == NULL)
  56                 return temp;
  57         else {
  58                 memset(temp, 0, sizeof(struct mid_q_entry));
  59                 temp->mid = smb_buffer->Mid;    /* always LE */
  60                 temp->pid = current->pid;
  61                 temp->command = cpu_to_le16(smb_buffer->Command);
  62                 cFYI(1, "For smb_command %d", smb_buffer->Command);
  63         /*      do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */
  64                 /* when mid allocated can be before when sent */
  65                 temp->when_alloc = jiffies;
  66                 temp->server = server;
  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 = cifs_wake_up_task;
  73                 temp->callback_data = current;
  74         }
  75
  76         atomic_inc(&midCount);
  77         temp->mid_state = MID_REQUEST_ALLOCATED;
  78         return temp;
  79 }
  80
  81 void
  82 DeleteMidQEntry(struct mid_q_entry *midEntry)
  83 {
  84 #ifdef CONFIG_CIFS_STATS2
  85         __le16 command = midEntry->server->vals->lock_cmd;
  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) && (midEntry->command != command)) {
 100                         printk(KERN_DEBUG " CIFS slow rsp: cmd %d mid %llu",
 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         unsigned int len = iov[0].iov_len;
 129         unsigned int total_len;
 130         int first_vec = 0;
 131         unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);
 132         struct socket *ssocket = server->ssocket;
 133
 134         if (ssocket == NULL)
 135                 return -ENOTSOCK; /* BB eventually add reconnect code here */
 136
 137         smb_msg.msg_name = (struct sockaddr *) &server->dstaddr;
 138         smb_msg.msg_namelen = sizeof(struct sockaddr);
 139         smb_msg.msg_control = NULL;
 140         smb_msg.msg_controllen = 0;
 141         if (server->noblocksnd)
 142                 smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL;
 143         else
 144                 smb_msg.msg_flags = MSG_NOSIGNAL;
 145
 146         total_len = 0;
 147         for (i = 0; i < n_vec; i++)
 148                 total_len += iov[i].iov_len;
 149
 150         cFYI(1, "Sending smb:  total_len %d", total_len);
 151         dump_smb(iov[0].iov_base, len);
 152
 153         i = 0;
 154         while (total_len) {
 155                 rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
 156                                     n_vec - first_vec, total_len);
 157                 if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
 158                         i++;
 159                         /*
 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 a response from
 166                          * the server in SendReceive[2] for the server to send
 167                          * a response back for most types of requests (except
 168                          * SMB Write past end of file which can be slow, and
 169                          * blocking lock operations). NFS waits slightly longer
 170                          * than CIFS, but this can make it take longer for
 171                          * nonresponsive servers to be detected and 15 seconds
 172                          * is more than enough time for modern networks to
 173                          * send a packet.  In most cases if we fail to send
 174                          * after the retries we will kill the socket and
 175                          * reconnect which may clear the network problem.
 176                          */
 177                         if ((i >= 14) || (!server->noblocksnd && (i > 2))) {
 178                                 cERROR(1, "sends on sock %p stuck for 15 seconds",
 179                                     ssocket);
 180                                 rc = -EAGAIN;
 181                                 break;
 182                         }
 183                         msleep(1 << i);
 184                         continue;
 185                 }
 186                 if (rc < 0)
 187                         break;
 188
 189                 if (rc == total_len) {
 190                         total_len = 0;
 191                         break;
 192                 } else if (rc > total_len) {
 193                         cERROR(1, "sent %d requested %d", rc, total_len);
 194                         break;
 195                 }
 196                 if (rc == 0) {
 197                         /* should never happen, letting socket clear before
 198                            retrying is our only obvious option here */
 199                         cERROR(1, "tcp sent no data");
 200                         msleep(500);
 201                         continue;
 202                 }
 203                 total_len -= rc;
 204                 /* the line below resets i */
 205                 for (i = first_vec; i < n_vec; i++) {
 206                         if (iov[i].iov_len) {
 207                                 if (rc > iov[i].iov_len) {
 208                                         rc -= iov[i].iov_len;
 209                                         iov[i].iov_len = 0;
 210                                 } else {
 211                                         iov[i].iov_base += rc;
 212                                         iov[i].iov_len -= rc;
 213                                         first_vec = i;
 214                                         break;
 215                                 }
 216                         }
 217                 }
 218                 i = 0; /* in case we get ENOSPC on the next send */
 219         }
 220
 221         if ((total_len > 0) && (total_len != smb_buf_length + 4)) {
 222                 cFYI(1, "partial send (%d remaining), terminating session",
 223                         total_len);
 224                 /* If we have only sent part of an SMB then the next SMB
 225                    could be taken as the remainder of this one.  We need
 226                    to kill the socket so the server throws away the partial
 227                    SMB */
 228                 server->tcpStatus = CifsNeedReconnect;
 229         }
 230
 231         if (rc < 0 && rc != -EINTR)
 232                 cERROR(1, "Error %d sending data on socket to server", rc);
 233         else
 234                 rc = 0;
 235
 236         return rc;
 237 }
 238
 239 int
 240 smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
 241          unsigned int smb_buf_length)
 242 {
 243         struct kvec iov;
 244
 245         iov.iov_base = smb_buffer;
 246         iov.iov_len = smb_buf_length + 4;
 247
 248         return smb_sendv(server, &iov, 1);
 249 }
 250
 251 static int
 252 wait_for_free_credits(struct TCP_Server_Info *server, const int timeout,
 253                       int *credits)
 254 {
 255         int rc;
 256
 257         spin_lock(&server->req_lock);
 258         if (timeout == CIFS_ASYNC_OP) {
 259                 /* oplock breaks must not be held up */
 260                 server->in_flight++;
 261                 *credits -= 1;
 262                 spin_unlock(&server->req_lock);
 263                 return 0;
 264         }
 265
 266         while (1) {
 267                 if (*credits <= 0) {
 268                         spin_unlock(&server->req_lock);
 269                         cifs_num_waiters_inc(server);
 270                         rc = wait_event_killable(server->request_q,
 271                                                  has_credits(server, credits));
 272                         cifs_num_waiters_dec(server);
 273                         if (rc)
 274                                 return rc;
 275                         spin_lock(&server->req_lock);
 276                 } else {
 277                         if (server->tcpStatus == CifsExiting) {
 278                                 spin_unlock(&server->req_lock);
 279                                 return -ENOENT;
 280                         }
 281
 282                         /*
 283                          * Can not count locking commands against total
 284                          * as they are allowed to block on server.
 285                          */
 286
 287                         /* update # of requests on the wire to server */
 288                         if (timeout != CIFS_BLOCKING_OP) {
 289                                 *credits -= 1;
 290                                 server->in_flight++;
 291                         }
 292                         spin_unlock(&server->req_lock);
 293                         break;
 294                 }
 295         }
 296         return 0;
 297 }
 298
 299 static int
 300 wait_for_free_request(struct TCP_Server_Info *server, const int timeout,
 301                       const int optype)
 302 {
 303         return wait_for_free_credits(server, timeout,
 304                                 server->ops->get_credits_field(server, optype));
 305 }
 306
 307 static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,
 308                         struct mid_q_entry **ppmidQ)
 309 {
 310         if (ses->server->tcpStatus == CifsExiting) {
 311                 return -ENOENT;
 312         }
 313
 314         if (ses->server->tcpStatus == CifsNeedReconnect) {
 315                 cFYI(1, "tcp session dead - return to caller to retry");
 316                 return -EAGAIN;
 317         }
 318
 319         if (ses->status != CifsGood) {
 320                 /* check if SMB session is bad because we are setting it up */
 321                 if ((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
 322                         (in_buf->Command != SMB_COM_NEGOTIATE))
 323                         return -EAGAIN;
 324                 /* else ok - we are setting up session */
 325         }
 326         *ppmidQ = AllocMidQEntry(in_buf, ses->server);
 327         if (*ppmidQ == NULL)
 328                 return -ENOMEM;
 329         spin_lock(&GlobalMid_Lock);
 330         list_add_tail(&(*ppmidQ)->qhead, &ses->server->pending_mid_q);
 331         spin_unlock(&GlobalMid_Lock);
 332         return 0;
 333 }
 334
 335 static int
 336 wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
 337 {
 338         int error;
 339
 340         error = wait_event_freezekillable(server->response_q,
 341                                     midQ->mid_state != MID_REQUEST_SUBMITTED);
 342         if (error < 0)
 343                 return -ERESTARTSYS;
 344
 345         return 0;
 346 }
 347
 348 int
 349 cifs_setup_async_request(struct TCP_Server_Info *server, struct kvec *iov,
 350                          unsigned int nvec, struct mid_q_entry **ret_mid)
 351 {
 352         int rc;
 353         struct smb_hdr *hdr = (struct smb_hdr *)iov[0].iov_base;
 354         struct mid_q_entry *mid;
 355
 356         /* enable signing if server requires it */
 357         if (server->sec_mode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
 358                 hdr->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 359
 360         mid = AllocMidQEntry(hdr, server);
 361         if (mid == NULL)
 362                 return -ENOMEM;
 363
 364         rc = cifs_sign_smbv(iov, nvec, server, &mid->sequence_number);
 365         if (rc) {
 366                 DeleteMidQEntry(mid);
 367                 return rc;
 368         }
 369
 370         *ret_mid = mid;
 371         return 0;
 372 }
 373
 374 /*
 375  * Send a SMB request and set the callback function in the mid to handle
 376  * the result. Caller is responsible for dealing with timeouts.
 377  */
 378 int
 379 cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
 380                 unsigned int nvec, mid_receive_t *receive,
 381                 mid_callback_t *callback, void *cbdata, const int flags)
 382 {
 383         int rc, timeout, optype;
 384         struct mid_q_entry *mid;
 385
 386         timeout = flags & CIFS_TIMEOUT_MASK;
 387         optype = flags & CIFS_OP_MASK;
 388
 389         rc = wait_for_free_request(server, timeout, optype);
 390         if (rc)
 391                 return rc;
 392
 393         mutex_lock(&server->srv_mutex);
 394         rc = server->ops->setup_async_request(server, iov, nvec, &mid);
 395         if (rc) {
 396                 mutex_unlock(&server->srv_mutex);
 397                 add_credits(server, 1, optype);
 398                 wake_up(&server->request_q);
 399                 return rc;
 400         }
 401
 402         mid->receive = receive;
 403         mid->callback = callback;
 404         mid->callback_data = cbdata;
 405         mid->mid_state = MID_REQUEST_SUBMITTED;
 406
 407         /* put it on the pending_mid_q */
 408         spin_lock(&GlobalMid_Lock);
 409         list_add_tail(&mid->qhead, &server->pending_mid_q);
 410         spin_unlock(&GlobalMid_Lock);
 411
 412
 413         cifs_in_send_inc(server);
 414         rc = smb_sendv(server, iov, nvec);
 415         cifs_in_send_dec(server);
 416         cifs_save_when_sent(mid);
 417         mutex_unlock(&server->srv_mutex);
 418
 419         if (rc == 0)
 420                 return 0;
 421
 422         delete_mid(mid);
 423         add_credits(server, 1, optype);
 424         wake_up(&server->request_q);
 425         return rc;
 426 }
 427
 428 /*
 429  *
 430  * Send an SMB Request.  No response info (other than return code)
 431  * needs to be parsed.
 432  *
 433  * flags indicate the type of request buffer and how long to wait
 434  * and whether to log NT STATUS code (error) before mapping it to POSIX error
 435  *
 436  */
 437 int
 438 SendReceiveNoRsp(const unsigned int xid, struct cifs_ses *ses,
 439                  char *in_buf, int flags)
 440 {
 441         int rc;
 442         struct kvec iov[1];
 443         int resp_buf_type;
 444
 445         iov[0].iov_base = in_buf;
 446         iov[0].iov_len = get_rfc1002_length(in_buf) + 4;
 447         flags |= CIFS_NO_RESP;
 448         rc = SendReceive2(xid, ses, iov, 1, &resp_buf_type, flags);
 449         cFYI(DBG2, "SendRcvNoRsp flags %d rc %d", flags, rc);
 450
 451         return rc;
 452 }
 453
 454 static int
 455 cifs_sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
 456 {
 457         int rc = 0;
 458
 459         cFYI(1, "%s: cmd=%d mid=%llu state=%d", __func__,
 460              le16_to_cpu(mid->command), mid->mid, mid->mid_state);
 461
 462         spin_lock(&GlobalMid_Lock);
 463         switch (mid->mid_state) {
 464         case MID_RESPONSE_RECEIVED:
 465                 spin_unlock(&GlobalMid_Lock);
 466                 return rc;
 467         case MID_RETRY_NEEDED:
 468                 rc = -EAGAIN;
 469                 break;
 470         case MID_RESPONSE_MALFORMED:
 471                 rc = -EIO;
 472                 break;
 473         case MID_SHUTDOWN:
 474                 rc = -EHOSTDOWN;
 475                 break;
 476         default:
 477                 list_del_init(&mid->qhead);
 478                 cERROR(1, "%s: invalid mid state mid=%llu state=%d", __func__,
 479                        mid->mid, mid->mid_state);
 480                 rc = -EIO;
 481         }
 482         spin_unlock(&GlobalMid_Lock);
 483
 484         DeleteMidQEntry(mid);
 485         return rc;
 486 }
 487
 488 static inline int
 489 send_cancel(struct TCP_Server_Info *server, void *buf, struct mid_q_entry *mid)
 490 {
 491         return server->ops->send_cancel ?
 492                                 server->ops->send_cancel(server, buf, mid) : 0;
 493 }
 494
 495 int
 496 cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 497                    bool log_error)
 498 {
 499         unsigned int len = get_rfc1002_length(mid->resp_buf) + 4;
 500
 501         dump_smb(mid->resp_buf, min_t(u32, 92, len));
 502
 503         /* convert the length into a more usable form */
 504         if (server->sec_mode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
 505                 struct kvec iov;
 506
 507                 iov.iov_base = mid->resp_buf;
 508                 iov.iov_len = len;
 509                 /* FIXME: add code to kill session */
 510                 if (cifs_verify_signature(&iov, 1, server,
 511                                           mid->sequence_number + 1) != 0)
 512                         cERROR(1, "Unexpected SMB signature");
 513         }
 514
 515         /* BB special case reconnect tid and uid here? */
 516         return map_smb_to_linux_error(mid->resp_buf, log_error);
 517 }
 518
 519 int
 520 cifs_setup_request(struct cifs_ses *ses, struct kvec *iov,
 521                    unsigned int nvec, struct mid_q_entry **ret_mid)
 522 {
 523         int rc;
 524         struct smb_hdr *hdr = (struct smb_hdr *)iov[0].iov_base;
 525         struct mid_q_entry *mid;
 526
 527         rc = allocate_mid(ses, hdr, &mid);
 528         if (rc)
 529                 return rc;
 530         rc = cifs_sign_smbv(iov, nvec, ses->server, &mid->sequence_number);
 531         if (rc)
 532                 delete_mid(mid);
 533         *ret_mid = mid;
 534         return rc;
 535 }
 536
 537 int
 538 SendReceive2(const unsigned int xid, struct cifs_ses *ses,
 539              struct kvec *iov, int n_vec, int *resp_buf_type /* ret */,
 540              const int flags)
 541 {
 542         int rc = 0;
 543         int timeout, optype;
 544         struct mid_q_entry *midQ;
 545         char *buf = iov[0].iov_base;
 546         unsigned int credits = 1;
 547
 548         timeout = flags & CIFS_TIMEOUT_MASK;
 549         optype = flags & CIFS_OP_MASK;
 550
 551         *resp_buf_type = CIFS_NO_BUFFER;  /* no response buf yet */
 552
 553         if ((ses == NULL) || (ses->server == NULL)) {
 554                 cifs_small_buf_release(buf);
 555                 cERROR(1, "Null session");
 556                 return -EIO;
 557         }
 558
 559         if (ses->server->tcpStatus == CifsExiting) {
 560                 cifs_small_buf_release(buf);
 561                 return -ENOENT;
 562         }
 563
 564         /*
 565          * Ensure that we do not send more than 50 overlapping requests
 566          * to the same server. We may make this configurable later or
 567          * use ses->maxReq.
 568          */
 569
 570         rc = wait_for_free_request(ses->server, timeout, optype);
 571         if (rc) {
 572                 cifs_small_buf_release(buf);
 573                 return rc;
 574         }
 575
 576         /*
 577          * Make sure that we sign in the same order that we send on this socket
 578          * and avoid races inside tcp sendmsg code that could cause corruption
 579          * of smb data.
 580          */
 581
 582         mutex_lock(&ses->server->srv_mutex);
 583
 584         rc = ses->server->ops->setup_request(ses, iov, n_vec, &midQ);
 585         if (rc) {
 586                 mutex_unlock(&ses->server->srv_mutex);
 587                 cifs_small_buf_release(buf);
 588                 /* Update # of requests on wire to server */
 589                 add_credits(ses->server, 1, optype);
 590                 return rc;
 591         }
 592
 593         midQ->mid_state = MID_REQUEST_SUBMITTED;
 594         cifs_in_send_inc(ses->server);
 595         rc = smb_sendv(ses->server, iov, n_vec);
 596         cifs_in_send_dec(ses->server);
 597         cifs_save_when_sent(midQ);
 598
 599         mutex_unlock(&ses->server->srv_mutex);
 600
 601         if (rc < 0) {
 602                 cifs_small_buf_release(buf);
 603                 goto out;
 604         }
 605
 606         if (timeout == CIFS_ASYNC_OP) {
 607                 cifs_small_buf_release(buf);
 608                 goto out;
 609         }
 610
 611         rc = wait_for_response(ses->server, midQ);
 612         if (rc != 0) {
 613                 send_cancel(ses->server, buf, midQ);
 614                 spin_lock(&GlobalMid_Lock);
 615                 if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
 616                         midQ->callback = DeleteMidQEntry;
 617                         spin_unlock(&GlobalMid_Lock);
 618                         cifs_small_buf_release(buf);
 619                         add_credits(ses->server, 1, optype);
 620                         return rc;
 621                 }
 622                 spin_unlock(&GlobalMid_Lock);
 623         }
 624
 625         cifs_small_buf_release(buf);
 626
 627         rc = cifs_sync_mid_result(midQ, ses->server);
 628         if (rc != 0) {
 629                 add_credits(ses->server, 1, optype);
 630                 return rc;
 631         }
 632
 633         if (!midQ->resp_buf || midQ->mid_state != MID_RESPONSE_RECEIVED) {
 634                 rc = -EIO;
 635                 cFYI(1, "Bad MID state?");
 636                 goto out;
 637         }
 638
 639         buf = (char *)midQ->resp_buf;
 640         iov[0].iov_base = buf;
 641         iov[0].iov_len = get_rfc1002_length(buf) + 4;
 642         if (midQ->large_buf)
 643                 *resp_buf_type = CIFS_LARGE_BUFFER;
 644         else
 645                 *resp_buf_type = CIFS_SMALL_BUFFER;
 646
 647         credits = ses->server->ops->get_credits(midQ);
 648
 649         rc = ses->server->ops->check_receive(midQ, ses->server,
 650                                              flags & CIFS_LOG_ERROR);
 651
 652         /* mark it so buf will not be freed by delete_mid */
 653         if ((flags & CIFS_NO_RESP) == 0)
 654                 midQ->resp_buf = NULL;
 655 out:
 656         delete_mid(midQ);
 657         add_credits(ses->server, credits, optype);
 658
 659         return rc;
 660 }
 661
 662 int
 663 SendReceive(const unsigned int xid, struct cifs_ses *ses,
 664             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
 665             int *pbytes_returned, const int timeout)
 666 {
 667         int rc = 0;
 668         struct mid_q_entry *midQ;
 669
 670         if (ses == NULL) {
 671                 cERROR(1, "Null smb session");
 672                 return -EIO;
 673         }
 674         if (ses->server == NULL) {
 675                 cERROR(1, "Null tcp session");
 676                 return -EIO;
 677         }
 678
 679         if (ses->server->tcpStatus == CifsExiting)
 680                 return -ENOENT;
 681
 682         /* Ensure that we do not send more than 50 overlapping requests
 683            to the same server. We may make this configurable later or
 684            use ses->maxReq */
 685
 686         if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
 687                         MAX_CIFS_HDR_SIZE - 4) {
 688                 cERROR(1, "Illegal length, greater than maximum frame, %d",
 689                            be32_to_cpu(in_buf->smb_buf_length));
 690                 return -EIO;
 691         }
 692
 693         rc = wait_for_free_request(ses->server, timeout, 0);
 694         if (rc)
 695                 return rc;
 696
 697         /* make sure that we sign in the same order that we send on this socket
 698            and avoid races inside tcp sendmsg code that could cause corruption
 699            of smb data */
 700
 701         mutex_lock(&ses->server->srv_mutex);
 702
 703         rc = allocate_mid(ses, in_buf, &midQ);
 704         if (rc) {
 705                 mutex_unlock(&ses->server->srv_mutex);
 706                 /* Update # of requests on wire to server */
 707                 add_credits(ses->server, 1, 0);
 708                 return rc;
 709         }
 710
 711         rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
 712         if (rc) {
 713                 mutex_unlock(&ses->server->srv_mutex);
 714                 goto out;
 715         }
 716
 717         midQ->mid_state = MID_REQUEST_SUBMITTED;
 718
 719         cifs_in_send_inc(ses->server);
 720         rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
 721         cifs_in_send_dec(ses->server);
 722         cifs_save_when_sent(midQ);
 723         mutex_unlock(&ses->server->srv_mutex);
 724
 725         if (rc < 0)
 726                 goto out;
 727
 728         if (timeout == CIFS_ASYNC_OP)
 729                 goto out;
 730
 731         rc = wait_for_response(ses->server, midQ);
 732         if (rc != 0) {
 733                 send_cancel(ses->server, in_buf, midQ);
 734                 spin_lock(&GlobalMid_Lock);
 735                 if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
 736                         /* no longer considered to be "in-flight" */
 737                         midQ->callback = DeleteMidQEntry;
 738                         spin_unlock(&GlobalMid_Lock);
 739                         add_credits(ses->server, 1, 0);
 740                         return rc;
 741                 }
 742                 spin_unlock(&GlobalMid_Lock);
 743         }
 744
 745         rc = cifs_sync_mid_result(midQ, ses->server);
 746         if (rc != 0) {
 747                 add_credits(ses->server, 1, 0);
 748                 return rc;
 749         }
 750
 751         if (!midQ->resp_buf || !out_buf ||
 752             midQ->mid_state != MID_RESPONSE_RECEIVED) {
 753                 rc = -EIO;
 754                 cERROR(1, "Bad MID state?");
 755                 goto out;
 756         }
 757
 758         *pbytes_returned = get_rfc1002_length(midQ->resp_buf);
 759         memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
 760         rc = cifs_check_receive(midQ, ses->server, 0);
 761 out:
 762         delete_mid(midQ);
 763         add_credits(ses->server, 1, 0);
 764
 765         return rc;
 766 }
 767
 768 /* We send a LOCKINGX_CANCEL_LOCK to cause the Windows
 769    blocking lock to return. */
 770
 771 static int
 772 send_lock_cancel(const unsigned int xid, struct cifs_tcon *tcon,
 773                         struct smb_hdr *in_buf,
 774                         struct smb_hdr *out_buf)
 775 {
 776         int bytes_returned;
 777         struct cifs_ses *ses = tcon->ses;
 778         LOCK_REQ *pSMB = (LOCK_REQ *)in_buf;
 779
 780         /* We just modify the current in_buf to change
 781            the type of lock from LOCKING_ANDX_SHARED_LOCK
 782            or LOCKING_ANDX_EXCLUSIVE_LOCK to
 783            LOCKING_ANDX_CANCEL_LOCK. */
 784
 785         pSMB->LockType = LOCKING_ANDX_CANCEL_LOCK|LOCKING_ANDX_LARGE_FILES;
 786         pSMB->Timeout = 0;
 787         pSMB->hdr.Mid = get_next_mid(ses->server);
 788
 789         return SendReceive(xid, ses, in_buf, out_buf,
 790                         &bytes_returned, 0);
 791 }
 792
 793 int
 794 SendReceiveBlockingLock(const unsigned int xid, struct cifs_tcon *tcon,
 795             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
 796             int *pbytes_returned)
 797 {
 798         int rc = 0;
 799         int rstart = 0;
 800         struct mid_q_entry *midQ;
 801         struct cifs_ses *ses;
 802
 803         if (tcon == NULL || tcon->ses == NULL) {
 804                 cERROR(1, "Null smb session");
 805                 return -EIO;
 806         }
 807         ses = tcon->ses;
 808
 809         if (ses->server == NULL) {
 810                 cERROR(1, "Null tcp session");
 811                 return -EIO;
 812         }
 813
 814         if (ses->server->tcpStatus == CifsExiting)
 815                 return -ENOENT;
 816
 817         /* Ensure that we do not send more than 50 overlapping requests
 818            to the same server. We may make this configurable later or
 819            use ses->maxReq */
 820
 821         if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
 822                         MAX_CIFS_HDR_SIZE - 4) {
 823                 cERROR(1, "Illegal length, greater than maximum frame, %d",
 824                            be32_to_cpu(in_buf->smb_buf_length));
 825                 return -EIO;
 826         }
 827
 828         rc = wait_for_free_request(ses->server, CIFS_BLOCKING_OP, 0);
 829         if (rc)
 830                 return rc;
 831
 832         /* make sure that we sign in the same order that we send on this socket
 833            and avoid races inside tcp sendmsg code that could cause corruption
 834            of smb data */
 835
 836         mutex_lock(&ses->server->srv_mutex);
 837
 838         rc = allocate_mid(ses, in_buf, &midQ);
 839         if (rc) {
 840                 mutex_unlock(&ses->server->srv_mutex);
 841                 return rc;
 842         }
 843
 844         rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
 845         if (rc) {
 846                 delete_mid(midQ);
 847                 mutex_unlock(&ses->server->srv_mutex);
 848                 return rc;
 849         }
 850
 851         midQ->mid_state = MID_REQUEST_SUBMITTED;
 852         cifs_in_send_inc(ses->server);
 853         rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
 854         cifs_in_send_dec(ses->server);
 855         cifs_save_when_sent(midQ);
 856         mutex_unlock(&ses->server->srv_mutex);
 857
 858         if (rc < 0) {
 859                 delete_mid(midQ);
 860                 return rc;
 861         }
 862
 863         /* Wait for a reply - allow signals to interrupt. */
 864         rc = wait_event_interruptible(ses->server->response_q,
 865                 (!(midQ->mid_state == MID_REQUEST_SUBMITTED)) ||
 866                 ((ses->server->tcpStatus != CifsGood) &&
 867                  (ses->server->tcpStatus != CifsNew)));
 868
 869         /* Were we interrupted by a signal ? */
 870         if ((rc == -ERESTARTSYS) &&
 871                 (midQ->mid_state == MID_REQUEST_SUBMITTED) &&
 872                 ((ses->server->tcpStatus == CifsGood) ||
 873                  (ses->server->tcpStatus == CifsNew))) {
 874
 875                 if (in_buf->Command == SMB_COM_TRANSACTION2) {
 876                         /* POSIX lock. We send a NT_CANCEL SMB to cause the
 877                            blocking lock to return. */
 878                         rc = send_cancel(ses->server, in_buf, midQ);
 879                         if (rc) {
 880                                 delete_mid(midQ);
 881                                 return rc;
 882                         }
 883                 } else {
 884                         /* Windows lock. We send a LOCKINGX_CANCEL_LOCK
 885                            to cause the blocking lock to return. */
 886
 887                         rc = send_lock_cancel(xid, tcon, in_buf, out_buf);
 888
 889                         /* If we get -ENOLCK back the lock may have
 890                            already been removed. Don't exit in this case. */
 891                         if (rc && rc != -ENOLCK) {
 892                                 delete_mid(midQ);
 893                                 return rc;
 894                         }
 895                 }
 896
 897                 rc = wait_for_response(ses->server, midQ);
 898                 if (rc) {
 899                         send_cancel(ses->server, in_buf, midQ);
 900                         spin_lock(&GlobalMid_Lock);
 901                         if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
 902                                 /* no longer considered to be "in-flight" */
 903                                 midQ->callback = DeleteMidQEntry;
 904                                 spin_unlock(&GlobalMid_Lock);
 905                                 return rc;
 906                         }
 907                         spin_unlock(&GlobalMid_Lock);
 908                 }
 909
 910                 /* We got the response - restart system call. */
 911                 rstart = 1;
 912         }
 913
 914         rc = cifs_sync_mid_result(midQ, ses->server);
 915         if (rc != 0)
 916                 return rc;
 917
 918         /* rcvd frame is ok */
 919         if (out_buf == NULL || midQ->mid_state != MID_RESPONSE_RECEIVED) {
 920                 rc = -EIO;
 921                 cERROR(1, "Bad MID state?");
 922                 goto out;
 923         }
 924
 925         *pbytes_returned = get_rfc1002_length(midQ->resp_buf);
 926         memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
 927         rc = cifs_check_receive(midQ, ses->server, 0);
 928 out:
 929         delete_mid(midQ);
 930         if (rstart && rc == -EACCES)
 931                 return -ERESTARTSYS;
 932         return rc;
 933 }