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 <linux/tcp.h>
  31 #include <linux/bvec.h>
  32 #include <linux/highmem.h>
  33 #include <linux/uaccess.h>
  34 #include <asm/processor.h>
  35 #include <linux/mempool.h>
  36 #include <linux/sched/signal.h>
  37 #include "cifspdu.h"
  38 #include "cifsglob.h"
  39 #include "cifsproto.h"
  40 #include "cifs_debug.h"
  41 #include "smb2proto.h"
  42 #include "smbdirect.h"
  43
  44 /* Max number of iovectors we can use off the stack when sending requests. */
  45 #define CIFS_MAX_IOV_SIZE 8
  46
  47 void
  48 cifs_wake_up_task(struct mid_q_entry *mid)
  49 {
  50         wake_up_process(mid->callback_data);
  51 }
  52
  53 struct mid_q_entry *
  54 AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
  55 {
  56         struct mid_q_entry *temp;
  57
  58         if (server == NULL) {
  59                 cifs_dbg(VFS, "Null TCP session in AllocMidQEntry\n");
  60                 return NULL;
  61         }
  62
  63         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
  64         memset(temp, 0, sizeof(struct mid_q_entry));
  65         kref_init(&temp->refcount);
  66         temp->mid = get_mid(smb_buffer);
  67         temp->pid = current->pid;
  68         temp->command = cpu_to_le16(smb_buffer->Command);
  69         cifs_dbg(FYI, "For smb_command %d\n", smb_buffer->Command);
  70         /*      do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */
  71         /* when mid allocated can be before when sent */
  72         temp->when_alloc = jiffies;
  73         temp->server = server;
  74
  75         /*
  76          * The default is for the mid to be synchronous, so the
  77          * default callback just wakes up the current task.
  78          */
  79         get_task_struct(current);
  80         temp->creator = current;
  81         temp->callback = cifs_wake_up_task;
  82         temp->callback_data = current;
  83
  84         atomic_inc(&midCount);
  85         temp->mid_state = MID_REQUEST_ALLOCATED;
  86         return temp;
  87 }
  88
  89 static void _cifs_mid_q_entry_release(struct kref *refcount)
  90 {
  91         struct mid_q_entry *midEntry =
  92                         container_of(refcount, struct mid_q_entry, refcount);
  93 #ifdef CONFIG_CIFS_STATS2
  94         __le16 command = midEntry->server->vals->lock_cmd;
  95         __u16 smb_cmd = le16_to_cpu(midEntry->command);
  96         unsigned long now;
  97         unsigned long roundtrip_time;
  98 #endif
  99         struct TCP_Server_Info *server = midEntry->server;
 100
 101         if (midEntry->resp_buf && (midEntry->mid_flags & MID_WAIT_CANCELLED) &&
 102             midEntry->mid_state == MID_RESPONSE_RECEIVED &&
 103             server->ops->handle_cancelled_mid)
 104                 server->ops->handle_cancelled_mid(midEntry->resp_buf, server);
 105
 106         midEntry->mid_state = MID_FREE;
 107         atomic_dec(&midCount);
 108         if (midEntry->large_buf)
 109                 cifs_buf_release(midEntry->resp_buf);
 110         else
 111                 cifs_small_buf_release(midEntry->resp_buf);
 112 #ifdef CONFIG_CIFS_STATS2
 113         now = jiffies;
 114         if (now < midEntry->when_alloc)
 115                 cifs_server_dbg(VFS, "invalid mid allocation time\n");
 116         roundtrip_time = now - midEntry->when_alloc;
 117
 118         if (smb_cmd < NUMBER_OF_SMB2_COMMANDS) {
 119                 if (atomic_read(&server->num_cmds[smb_cmd]) == 0) {
 120                         server->slowest_cmd[smb_cmd] = roundtrip_time;
 121                         server->fastest_cmd[smb_cmd] = roundtrip_time;
 122                 } else {
 123                         if (server->slowest_cmd[smb_cmd] < roundtrip_time)
 124                                 server->slowest_cmd[smb_cmd] = roundtrip_time;
 125                         else if (server->fastest_cmd[smb_cmd] > roundtrip_time)
 126                                 server->fastest_cmd[smb_cmd] = roundtrip_time;
 127                 }
 128                 cifs_stats_inc(&server->num_cmds[smb_cmd]);
 129                 server->time_per_cmd[smb_cmd] += roundtrip_time;
 130         }
 131         /*
 132          * commands taking longer than one second (default) can be indications
 133          * that something is wrong, unless it is quite a slow link or a very
 134          * busy server. Note that this calc is unlikely or impossible to wrap
 135          * as long as slow_rsp_threshold is not set way above recommended max
 136          * value (32767 ie 9 hours) and is generally harmless even if wrong
 137          * since only affects debug counters - so leaving the calc as simple
 138          * comparison rather than doing multiple conversions and overflow
 139          * checks
 140          */
 141         if ((slow_rsp_threshold != 0) &&
 142             time_after(now, midEntry->when_alloc + (slow_rsp_threshold * HZ)) &&
 143             (midEntry->command != command)) {
 144                 /*
 145                  * smb2slowcmd[NUMBER_OF_SMB2_COMMANDS] counts by command
 146                  * NB: le16_to_cpu returns unsigned so can not be negative below
 147                  */
 148                 if (smb_cmd < NUMBER_OF_SMB2_COMMANDS)
 149                         cifs_stats_inc(&server->smb2slowcmd[smb_cmd]);
 150
 151                 trace_smb3_slow_rsp(smb_cmd, midEntry->mid, midEntry->pid,
 152                                midEntry->when_sent, midEntry->when_received);
 153                 if (cifsFYI & CIFS_TIMER) {
 154                         pr_debug(" CIFS slow rsp: cmd %d mid %llu",
 155                                midEntry->command, midEntry->mid);
 156                         cifs_info(" A: 0x%lx S: 0x%lx R: 0x%lx\n",
 157                                now - midEntry->when_alloc,
 158                                now - midEntry->when_sent,
 159                                now - midEntry->when_received);
 160                 }
 161         }
 162 #endif
 163         put_task_struct(midEntry->creator);
 164
 165         mempool_free(midEntry, cifs_mid_poolp);
 166 }
 167
 168 void cifs_mid_q_entry_release(struct mid_q_entry *midEntry)
 169 {
 170         spin_lock(&GlobalMid_Lock);
 171         kref_put(&midEntry->refcount, _cifs_mid_q_entry_release);
 172         spin_unlock(&GlobalMid_Lock);
 173 }
 174
 175 void DeleteMidQEntry(struct mid_q_entry *midEntry)
 176 {
 177         cifs_mid_q_entry_release(midEntry);
 178 }
 179
 180 void
 181 cifs_delete_mid(struct mid_q_entry *mid)
 182 {
 183         spin_lock(&GlobalMid_Lock);
 184         if (!(mid->mid_flags & MID_DELETED)) {
 185                 list_del_init(&mid->qhead);
 186                 mid->mid_flags |= MID_DELETED;
 187         }
 188         spin_unlock(&GlobalMid_Lock);
 189
 190         DeleteMidQEntry(mid);
 191 }
 192
 193 /*
 194  * smb_send_kvec - send an array of kvecs to the server
 195  * @server:     Server to send the data to
 196  * @smb_msg:    Message to send
 197  * @sent:       amount of data sent on socket is stored here
 198  *
 199  * Our basic "send data to server" function. Should be called with srv_mutex
 200  * held. The caller is responsible for handling the results.
 201  */
 202 static int
 203 smb_send_kvec(struct TCP_Server_Info *server, struct msghdr *smb_msg,
 204               size_t *sent)
 205 {
 206         int rc = 0;
 207         int retries = 0;
 208         struct socket *ssocket = server->ssocket;
 209
 210         *sent = 0;
 211
 212         smb_msg->msg_name = (struct sockaddr *) &server->dstaddr;
 213         smb_msg->msg_namelen = sizeof(struct sockaddr);
 214         smb_msg->msg_control = NULL;
 215         smb_msg->msg_controllen = 0;
 216         if (server->noblocksnd)
 217                 smb_msg->msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL;
 218         else
 219                 smb_msg->msg_flags = MSG_NOSIGNAL;
 220
 221         while (msg_data_left(smb_msg)) {
 222                 /*
 223                  * If blocking send, we try 3 times, since each can block
 224                  * for 5 seconds. For nonblocking  we have to try more
 225                  * but wait increasing amounts of time allowing time for
 226                  * socket to clear.  The overall time we wait in either
 227                  * case to send on the socket is about 15 seconds.
 228                  * Similarly we wait for 15 seconds for a response from
 229                  * the server in SendReceive[2] for the server to send
 230                  * a response back for most types of requests (except
 231                  * SMB Write past end of file which can be slow, and
 232                  * blocking lock operations). NFS waits slightly longer
 233                  * than CIFS, but this can make it take longer for
 234                  * nonresponsive servers to be detected and 15 seconds
 235                  * is more than enough time for modern networks to
 236                  * send a packet.  In most cases if we fail to send
 237                  * after the retries we will kill the socket and
 238                  * reconnect which may clear the network problem.
 239                  */
 240                 rc = sock_sendmsg(ssocket, smb_msg);
 241                 if (rc == -EAGAIN) {
 242                         retries++;
 243                         if (retries >= 14 ||
 244                             (!server->noblocksnd && (retries > 2))) {
 245                                 cifs_server_dbg(VFS, "sends on sock %p stuck for 15 seconds\n",
 246                                          ssocket);
 247                                 return -EAGAIN;
 248                         }
 249                         msleep(1 << retries);
 250                         continue;
 251                 }
 252
 253                 if (rc < 0)
 254                         return rc;
 255
 256                 if (rc == 0) {
 257                         /* should never happen, letting socket clear before
 258                            retrying is our only obvious option here */
 259                         cifs_server_dbg(VFS, "tcp sent no data\n");
 260                         msleep(500);
 261                         continue;
 262                 }
 263
 264                 /* send was at least partially successful */
 265                 *sent += rc;
 266                 retries = 0; /* in case we get ENOSPC on the next send */
 267         }
 268         return 0;
 269 }
 270
 271 unsigned long
 272 smb_rqst_len(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 273 {
 274         unsigned int i;
 275         struct kvec *iov;
 276         int nvec;
 277         unsigned long buflen = 0;
 278
 279         if (server->vals->header_preamble_size == 0 &&
 280             rqst->rq_nvec >= 2 && rqst->rq_iov[0].iov_len == 4) {
 281                 iov = &rqst->rq_iov[1];
 282                 nvec = rqst->rq_nvec - 1;
 283         } else {
 284                 iov = rqst->rq_iov;
 285                 nvec = rqst->rq_nvec;
 286         }
 287
 288         /* total up iov array first */
 289         for (i = 0; i < nvec; i++)
 290                 buflen += iov[i].iov_len;
 291
 292         /*
 293          * Add in the page array if there is one. The caller needs to make
 294          * sure rq_offset and rq_tailsz are set correctly. If a buffer of
 295          * multiple pages ends at page boundary, rq_tailsz needs to be set to
 296          * PAGE_SIZE.
 297          */
 298         if (rqst->rq_npages) {
 299                 if (rqst->rq_npages == 1)
 300                         buflen += rqst->rq_tailsz;
 301                 else {
 302                         /*
 303                          * If there is more than one page, calculate the
 304                          * buffer length based on rq_offset and rq_tailsz
 305                          */
 306                         buflen += rqst->rq_pagesz * (rqst->rq_npages - 1) -
 307                                         rqst->rq_offset;
 308                         buflen += rqst->rq_tailsz;
 309                 }
 310         }
 311
 312         return buflen;
 313 }
 314
 315 static int
 316 __smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 317                 struct smb_rqst *rqst)
 318 {
 319         int rc = 0;
 320         struct kvec *iov;
 321         int n_vec;
 322         unsigned int send_length = 0;
 323         unsigned int i, j;
 324         sigset_t mask, oldmask;
 325         size_t total_len = 0, sent, size;
 326         struct socket *ssocket = server->ssocket;
 327         struct msghdr smb_msg;
 328         int val = 1;
 329         __be32 rfc1002_marker;
 330
 331         if (cifs_rdma_enabled(server)) {
 332                 /* return -EAGAIN when connecting or reconnecting */
 333                 rc = -EAGAIN;
 334                 if (server->smbd_conn)
 335                         rc = smbd_send(server, num_rqst, rqst);
 336                 goto smbd_done;
 337         }
 338
 339         if (ssocket == NULL)
 340                 return -EAGAIN;
 341
 342         if (signal_pending(current)) {
 343                 cifs_dbg(FYI, "signal is pending before sending any data\n");
 344                 return -EINTR;
 345         }
 346
 347         /* cork the socket */
 348         kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
 349                                 (char *)&val, sizeof(val));
 350
 351         for (j = 0; j < num_rqst; j++)
 352                 send_length += smb_rqst_len(server, &rqst[j]);
 353         rfc1002_marker = cpu_to_be32(send_length);
 354
 355         /*
 356          * We should not allow signals to interrupt the network send because
 357          * any partial send will cause session reconnects thus increasing
 358          * latency of system calls and overload a server with unnecessary
 359          * requests.
 360          */
 361
 362         sigfillset(&mask);
 363         sigprocmask(SIG_BLOCK, &mask, &oldmask);
 364
 365         /* Generate a rfc1002 marker for SMB2+ */
 366         if (server->vals->header_preamble_size == 0) {
 367                 struct kvec hiov = {
 368                         .iov_base = &rfc1002_marker,
 369                         .iov_len  = 4
 370                 };
 371                 iov_iter_kvec(&smb_msg.msg_iter, WRITE, &hiov, 1, 4);
 372                 rc = smb_send_kvec(server, &smb_msg, &sent);
 373                 if (rc < 0)
 374                         goto unmask;
 375
 376                 total_len += sent;
 377                 send_length += 4;
 378         }
 379
 380         cifs_dbg(FYI, "Sending smb: smb_len=%u\n", send_length);
 381
 382         for (j = 0; j < num_rqst; j++) {
 383                 iov = rqst[j].rq_iov;
 384                 n_vec = rqst[j].rq_nvec;
 385
 386                 size = 0;
 387                 for (i = 0; i < n_vec; i++) {
 388                         dump_smb(iov[i].iov_base, iov[i].iov_len);
 389                         size += iov[i].iov_len;
 390                 }
 391
 392                 iov_iter_kvec(&smb_msg.msg_iter, WRITE, iov, n_vec, size);
 393
 394                 rc = smb_send_kvec(server, &smb_msg, &sent);
 395                 if (rc < 0)
 396                         goto unmask;
 397
 398                 total_len += sent;
 399
 400                 /* now walk the page array and send each page in it */
 401                 for (i = 0; i < rqst[j].rq_npages; i++) {
 402                         struct bio_vec bvec;
 403
 404                         bvec.bv_page = rqst[j].rq_pages[i];
 405                         rqst_page_get_length(&rqst[j], i, &bvec.bv_len,
 406                                              &bvec.bv_offset);
 407
 408                         iov_iter_bvec(&smb_msg.msg_iter, WRITE,
 409                                       &bvec, 1, bvec.bv_len);
 410                         rc = smb_send_kvec(server, &smb_msg, &sent);
 411                         if (rc < 0)
 412                                 break;
 413
 414                         total_len += sent;
 415                 }
 416         }
 417
 418 unmask:
 419         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 420
 421         /*
 422          * If signal is pending but we have already sent the whole packet to
 423          * the server we need to return success status to allow a corresponding
 424          * mid entry to be kept in the pending requests queue thus allowing
 425          * to handle responses from the server by the client.
 426          *
 427          * If only part of the packet has been sent there is no need to hide
 428          * interrupt because the session will be reconnected anyway, so there
 429          * won't be any response from the server to handle.
 430          */
 431
 432         if (signal_pending(current) && (total_len != send_length)) {
 433                 cifs_dbg(FYI, "signal is pending after attempt to send\n");
 434                 rc = -EINTR;
 435         }
 436
 437         /* uncork it */
 438         val = 0;
 439         kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
 440                                 (char *)&val, sizeof(val));
 441
 442         if ((total_len > 0) && (total_len != send_length)) {
 443                 cifs_dbg(FYI, "partial send (wanted=%u sent=%zu): terminating session\n",
 444                          send_length, total_len);
 445                 /*
 446                  * If we have only sent part of an SMB then the next SMB could
 447                  * be taken as the remainder of this one. We need to kill the
 448                  * socket so the server throws away the partial SMB
 449                  */
 450                 server->tcpStatus = CifsNeedReconnect;
 451                 trace_smb3_partial_send_reconnect(server->CurrentMid,
 452                                                   server->hostname);
 453         }
 454 smbd_done:
 455         if (rc < 0 && rc != -EINTR)
 456                 cifs_server_dbg(VFS, "Error %d sending data on socket to server\n",
 457                          rc);
 458         else if (rc > 0)
 459                 rc = 0;
 460
 461         return rc;
 462 }
 463
 464 static int
 465 smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 466               struct smb_rqst *rqst, int flags)
 467 {
 468         struct kvec iov;
 469         struct smb2_transform_hdr tr_hdr;
 470         struct smb_rqst cur_rqst[MAX_COMPOUND];
 471         int rc;
 472
 473         if (!(flags & CIFS_TRANSFORM_REQ))
 474                 return __smb_send_rqst(server, num_rqst, rqst);
 475
 476         if (num_rqst > MAX_COMPOUND - 1)
 477                 return -ENOMEM;
 478
 479         memset(&cur_rqst[0], 0, sizeof(cur_rqst));
 480         memset(&iov, 0, sizeof(iov));
 481         memset(&tr_hdr, 0, sizeof(tr_hdr));
 482
 483         iov.iov_base = &tr_hdr;
 484         iov.iov_len = sizeof(tr_hdr);
 485         cur_rqst[0].rq_iov = &iov;
 486         cur_rqst[0].rq_nvec = 1;
 487
 488         if (!server->ops->init_transform_rq) {
 489                 cifs_server_dbg(VFS, "Encryption requested but transform "
 490                                 "callback is missing\n");
 491                 return -EIO;
 492         }
 493
 494         rc = server->ops->init_transform_rq(server, num_rqst + 1,
 495                                             &cur_rqst[0], rqst);
 496         if (rc)
 497                 return rc;
 498
 499         rc = __smb_send_rqst(server, num_rqst + 1, &cur_rqst[0]);
 500         smb3_free_compound_rqst(num_rqst, &cur_rqst[1]);
 501         return rc;
 502 }
 503
 504 int
 505 smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
 506          unsigned int smb_buf_length)
 507 {
 508         struct kvec iov[2];
 509         struct smb_rqst rqst = { .rq_iov = iov,
 510                                  .rq_nvec = 2 };
 511
 512         iov[0].iov_base = smb_buffer;
 513         iov[0].iov_len = 4;
 514         iov[1].iov_base = (char *)smb_buffer + 4;
 515         iov[1].iov_len = smb_buf_length;
 516
 517         return __smb_send_rqst(server, 1, &rqst);
 518 }
 519
 520 static int
 521 wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits,
 522                       const int timeout, const int flags,
 523                       unsigned int *instance)
 524 {
 525         int rc;
 526         int *credits;
 527         int optype;
 528         long int t;
 529
 530         if (timeout < 0)
 531                 t = MAX_JIFFY_OFFSET;
 532         else
 533                 t = msecs_to_jiffies(timeout);
 534
 535         optype = flags & CIFS_OP_MASK;
 536
 537         *instance = 0;
 538
 539         credits = server->ops->get_credits_field(server, optype);
 540         /* Since an echo is already inflight, no need to wait to send another */
 541         if (*credits <= 0 && optype == CIFS_ECHO_OP)
 542                 return -EAGAIN;
 543
 544         spin_lock(&server->req_lock);
 545         if ((flags & CIFS_TIMEOUT_MASK) == CIFS_NON_BLOCKING) {
 546                 /* oplock breaks must not be held up */
 547                 server->in_flight++;
 548                 if (server->in_flight > server->max_in_flight)
 549                         server->max_in_flight = server->in_flight;
 550                 *credits -= 1;
 551                 *instance = server->reconnect_instance;
 552                 spin_unlock(&server->req_lock);
 553                 return 0;
 554         }
 555
 556         while (1) {
 557                 if (*credits < num_credits) {
 558                         spin_unlock(&server->req_lock);
 559                         cifs_num_waiters_inc(server);
 560                         rc = wait_event_killable_timeout(server->request_q,
 561                                 has_credits(server, credits, num_credits), t);
 562                         cifs_num_waiters_dec(server);
 563                         if (!rc) {
 564                                 trace_smb3_credit_timeout(server->CurrentMid,
 565                                         server->hostname, num_credits);
 566                                 cifs_server_dbg(VFS, "wait timed out after %d ms\n",
 567                                          timeout);
 568                                 return -ENOTSUPP;
 569                         }
 570                         if (rc == -ERESTARTSYS)
 571                                 return -ERESTARTSYS;
 572                         spin_lock(&server->req_lock);
 573                 } else {
 574                         if (server->tcpStatus == CifsExiting) {
 575                                 spin_unlock(&server->req_lock);
 576                                 return -ENOENT;
 577                         }
 578
 579                         /*
 580                          * For normal commands, reserve the last MAX_COMPOUND
 581                          * credits to compound requests.
 582                          * Otherwise these compounds could be permanently
 583                          * starved for credits by single-credit requests.
 584                          *
 585                          * To prevent spinning CPU, block this thread until
 586                          * there are >MAX_COMPOUND credits available.
 587                          * But only do this is we already have a lot of
 588                          * credits in flight to avoid triggering this check
 589                          * for servers that are slow to hand out credits on
 590                          * new sessions.
 591                          */
 592                         if (!optype && num_credits == 1 &&
 593                             server->in_flight > 2 * MAX_COMPOUND &&
 594                             *credits <= MAX_COMPOUND) {
 595                                 spin_unlock(&server->req_lock);
 596                                 cifs_num_waiters_inc(server);
 597                                 rc = wait_event_killable_timeout(
 598                                         server->request_q,
 599                                         has_credits(server, credits,
 600                                                     MAX_COMPOUND + 1),
 601                                         t);
 602                                 cifs_num_waiters_dec(server);
 603                                 if (!rc) {
 604                                         trace_smb3_credit_timeout(
 605                                                 server->CurrentMid,
 606                                                 server->hostname, num_credits);
 607                                         cifs_server_dbg(VFS, "wait timed out after %d ms\n",
 608                                                  timeout);
 609                                         return -ENOTSUPP;
 610                                 }
 611                                 if (rc == -ERESTARTSYS)
 612                                         return -ERESTARTSYS;
 613                                 spin_lock(&server->req_lock);
 614                                 continue;
 615                         }
 616
 617                         /*
 618                          * Can not count locking commands against total
 619                          * as they are allowed to block on server.
 620                          */
 621
 622                         /* update # of requests on the wire to server */
 623                         if ((flags & CIFS_TIMEOUT_MASK) != CIFS_BLOCKING_OP) {
 624                                 *credits -= num_credits;
 625                                 server->in_flight += num_credits;
 626                                 if (server->in_flight > server->max_in_flight)
 627                                         server->max_in_flight = server->in_flight;
 628                                 *instance = server->reconnect_instance;
 629                         }
 630                         spin_unlock(&server->req_lock);
 631                         break;
 632                 }
 633         }
 634         return 0;
 635 }
 636
 637 static int
 638 wait_for_free_request(struct TCP_Server_Info *server, const int flags,
 639                       unsigned int *instance)
 640 {
 641         return wait_for_free_credits(server, 1, -1, flags,
 642                                      instance);
 643 }
 644
 645 static int
 646 wait_for_compound_request(struct TCP_Server_Info *server, int num,
 647                           const int flags, unsigned int *instance)
 648 {
 649         int *credits;
 650
 651         credits = server->ops->get_credits_field(server, flags & CIFS_OP_MASK);
 652
 653         spin_lock(&server->req_lock);
 654         if (*credits < num) {
 655                 /*
 656                  * Return immediately if not too many requests in flight since
 657                  * we will likely be stuck on waiting for credits.
 658                  */
 659                 if (server->in_flight < num - *credits) {
 660                         spin_unlock(&server->req_lock);
 661                         return -ENOTSUPP;
 662                 }
 663         }
 664         spin_unlock(&server->req_lock);
 665
 666         return wait_for_free_credits(server, num, 60000, flags,
 667                                      instance);
 668 }
 669
 670 int
 671 cifs_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size,
 672                       unsigned int *num, struct cifs_credits *credits)
 673 {
 674         *num = size;
 675         credits->value = 0;
 676         credits->instance = server->reconnect_instance;
 677         return 0;
 678 }
 679
 680 static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,
 681                         struct mid_q_entry **ppmidQ)
 682 {
 683         if (ses->server->tcpStatus == CifsExiting) {
 684                 return -ENOENT;
 685         }
 686
 687         if (ses->server->tcpStatus == CifsNeedReconnect) {
 688                 cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
 689                 return -EAGAIN;
 690         }
 691
 692         if (ses->status == CifsNew) {
 693                 if ((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
 694                         (in_buf->Command != SMB_COM_NEGOTIATE))
 695                         return -EAGAIN;
 696                 /* else ok - we are setting up session */
 697         }
 698
 699         if (ses->status == CifsExiting) {
 700                 /* check if SMB session is bad because we are setting it up */
 701                 if (in_buf->Command != SMB_COM_LOGOFF_ANDX)
 702                         return -EAGAIN;
 703                 /* else ok - we are shutting down session */
 704         }
 705
 706         *ppmidQ = AllocMidQEntry(in_buf, ses->server);
 707         if (*ppmidQ == NULL)
 708                 return -ENOMEM;
 709         spin_lock(&GlobalMid_Lock);
 710         list_add_tail(&(*ppmidQ)->qhead, &ses->server->pending_mid_q);
 711         spin_unlock(&GlobalMid_Lock);
 712         return 0;
 713 }
 714
 715 static int
 716 wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
 717 {
 718         int error;
 719
 720         error = wait_event_freezekillable_unsafe(server->response_q,
 721                                     midQ->mid_state != MID_REQUEST_SUBMITTED);
 722         if (error < 0)
 723                 return -ERESTARTSYS;
 724
 725         return 0;
 726 }
 727
 728 struct mid_q_entry *
 729 cifs_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 730 {
 731         int rc;
 732         struct smb_hdr *hdr = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
 733         struct mid_q_entry *mid;
 734
 735         if (rqst->rq_iov[0].iov_len != 4 ||
 736             rqst->rq_iov[0].iov_base + 4 != rqst->rq_iov[1].iov_base)
 737                 return ERR_PTR(-EIO);
 738
 739         /* enable signing if server requires it */
 740         if (server->sign)
 741                 hdr->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 742
 743         mid = AllocMidQEntry(hdr, server);
 744         if (mid == NULL)
 745                 return ERR_PTR(-ENOMEM);
 746
 747         rc = cifs_sign_rqst(rqst, server, &mid->sequence_number);
 748         if (rc) {
 749                 DeleteMidQEntry(mid);
 750                 return ERR_PTR(rc);
 751         }
 752
 753         return mid;
 754 }
 755
 756 /*
 757  * Send a SMB request and set the callback function in the mid to handle
 758  * the result. Caller is responsible for dealing with timeouts.
 759  */
 760 int
 761 cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,
 762                 mid_receive_t *receive, mid_callback_t *callback,
 763                 mid_handle_t *handle, void *cbdata, const int flags,
 764                 const struct cifs_credits *exist_credits)
 765 {
 766         int rc;
 767         struct mid_q_entry *mid;
 768         struct cifs_credits credits = { .value = 0, .instance = 0 };
 769         unsigned int instance;
 770         int optype;
 771
 772         optype = flags & CIFS_OP_MASK;
 773
 774         if ((flags & CIFS_HAS_CREDITS) == 0) {
 775                 rc = wait_for_free_request(server, flags, &instance);
 776                 if (rc)
 777                         return rc;
 778                 credits.value = 1;
 779                 credits.instance = instance;
 780         } else
 781                 instance = exist_credits->instance;
 782
 783         mutex_lock(&server->srv_mutex);
 784
 785         /*
 786          * We can't use credits obtained from the previous session to send this
 787          * request. Check if there were reconnects after we obtained credits and
 788          * return -EAGAIN in such cases to let callers handle it.
 789          */
 790         if (instance != server->reconnect_instance) {
 791                 mutex_unlock(&server->srv_mutex);
 792                 add_credits_and_wake_if(server, &credits, optype);
 793                 return -EAGAIN;
 794         }
 795
 796         mid = server->ops->setup_async_request(server, rqst);
 797         if (IS_ERR(mid)) {
 798                 mutex_unlock(&server->srv_mutex);
 799                 add_credits_and_wake_if(server, &credits, optype);
 800                 return PTR_ERR(mid);
 801         }
 802
 803         mid->receive = receive;
 804         mid->callback = callback;
 805         mid->callback_data = cbdata;
 806         mid->handle = handle;
 807         mid->mid_state = MID_REQUEST_SUBMITTED;
 808
 809         /* put it on the pending_mid_q */
 810         spin_lock(&GlobalMid_Lock);
 811         list_add_tail(&mid->qhead, &server->pending_mid_q);
 812         spin_unlock(&GlobalMid_Lock);
 813
 814         /*
 815          * Need to store the time in mid before calling I/O. For call_async,
 816          * I/O response may come back and free the mid entry on another thread.
 817          */
 818         cifs_save_when_sent(mid);
 819         cifs_in_send_inc(server);
 820         rc = smb_send_rqst(server, 1, rqst, flags);
 821         cifs_in_send_dec(server);
 822
 823         if (rc < 0) {
 824                 revert_current_mid(server, mid->credits);
 825                 server->sequence_number -= 2;
 826                 cifs_delete_mid(mid);
 827         }
 828
 829         mutex_unlock(&server->srv_mutex);
 830
 831         if (rc == 0)
 832                 return 0;
 833
 834         add_credits_and_wake_if(server, &credits, optype);
 835         return rc;
 836 }
 837
 838 /*
 839  *
 840  * Send an SMB Request.  No response info (other than return code)
 841  * needs to be parsed.
 842  *
 843  * flags indicate the type of request buffer and how long to wait
 844  * and whether to log NT STATUS code (error) before mapping it to POSIX error
 845  *
 846  */
 847 int
 848 SendReceiveNoRsp(const unsigned int xid, struct cifs_ses *ses,
 849                  char *in_buf, int flags)
 850 {
 851         int rc;
 852         struct kvec iov[1];
 853         struct kvec rsp_iov;
 854         int resp_buf_type;
 855
 856         iov[0].iov_base = in_buf;
 857         iov[0].iov_len = get_rfc1002_length(in_buf) + 4;
 858         flags |= CIFS_NO_RSP_BUF;
 859         rc = SendReceive2(xid, ses, iov, 1, &resp_buf_type, flags, &rsp_iov);
 860         cifs_dbg(NOISY, "SendRcvNoRsp flags %d rc %d\n", flags, rc);
 861
 862         return rc;
 863 }
 864
 865 static int
 866 cifs_sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
 867 {
 868         int rc = 0;
 869
 870         cifs_dbg(FYI, "%s: cmd=%d mid=%llu state=%d\n",
 871                  __func__, le16_to_cpu(mid->command), mid->mid, mid->mid_state);
 872
 873         spin_lock(&GlobalMid_Lock);
 874         switch (mid->mid_state) {
 875         case MID_RESPONSE_RECEIVED:
 876                 spin_unlock(&GlobalMid_Lock);
 877                 return rc;
 878         case MID_RETRY_NEEDED:
 879                 rc = -EAGAIN;
 880                 break;
 881         case MID_RESPONSE_MALFORMED:
 882                 rc = -EIO;
 883                 break;
 884         case MID_SHUTDOWN:
 885                 rc = -EHOSTDOWN;
 886                 break;
 887         default:
 888                 if (!(mid->mid_flags & MID_DELETED)) {
 889                         list_del_init(&mid->qhead);
 890                         mid->mid_flags |= MID_DELETED;
 891                 }
 892                 cifs_server_dbg(VFS, "%s: invalid mid state mid=%llu state=%d\n",
 893                          __func__, mid->mid, mid->mid_state);
 894                 rc = -EIO;
 895         }
 896         spin_unlock(&GlobalMid_Lock);
 897
 898         DeleteMidQEntry(mid);
 899         return rc;
 900 }
 901
 902 static inline int
 903 send_cancel(struct TCP_Server_Info *server, struct smb_rqst *rqst,
 904             struct mid_q_entry *mid)
 905 {
 906         return server->ops->send_cancel ?
 907                                 server->ops->send_cancel(server, rqst, mid) : 0;
 908 }
 909
 910 int
 911 cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 912                    bool log_error)
 913 {
 914         unsigned int len = get_rfc1002_length(mid->resp_buf) + 4;
 915
 916         dump_smb(mid->resp_buf, min_t(u32, 92, len));
 917
 918         /* convert the length into a more usable form */
 919         if (server->sign) {
 920                 struct kvec iov[2];
 921                 int rc = 0;
 922                 struct smb_rqst rqst = { .rq_iov = iov,
 923                                          .rq_nvec = 2 };
 924
 925                 iov[0].iov_base = mid->resp_buf;
 926                 iov[0].iov_len = 4;
 927                 iov[1].iov_base = (char *)mid->resp_buf + 4;
 928                 iov[1].iov_len = len - 4;
 929                 /* FIXME: add code to kill session */
 930                 rc = cifs_verify_signature(&rqst, server,
 931                                            mid->sequence_number);
 932                 if (rc)
 933                         cifs_server_dbg(VFS, "SMB signature verification returned error = %d\n",
 934                                  rc);
 935         }
 936
 937         /* BB special case reconnect tid and uid here? */
 938         return map_smb_to_linux_error(mid->resp_buf, log_error);
 939 }
 940
 941 struct mid_q_entry *
 942 cifs_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
 943 {
 944         int rc;
 945         struct smb_hdr *hdr = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
 946         struct mid_q_entry *mid;
 947
 948         if (rqst->rq_iov[0].iov_len != 4 ||
 949             rqst->rq_iov[0].iov_base + 4 != rqst->rq_iov[1].iov_base)
 950                 return ERR_PTR(-EIO);
 951
 952         rc = allocate_mid(ses, hdr, &mid);
 953         if (rc)
 954                 return ERR_PTR(rc);
 955         rc = cifs_sign_rqst(rqst, ses->server, &mid->sequence_number);
 956         if (rc) {
 957                 cifs_delete_mid(mid);
 958                 return ERR_PTR(rc);
 959         }
 960         return mid;
 961 }
 962
 963 static void
 964 cifs_compound_callback(struct mid_q_entry *mid)
 965 {
 966         struct TCP_Server_Info *server = mid->server;
 967         struct cifs_credits credits;
 968
 969         credits.value = server->ops->get_credits(mid);
 970         credits.instance = server->reconnect_instance;
 971
 972         add_credits(server, &credits, mid->optype);
 973 }
 974
 975 static void
 976 cifs_compound_last_callback(struct mid_q_entry *mid)
 977 {
 978         cifs_compound_callback(mid);
 979         cifs_wake_up_task(mid);
 980 }
 981
 982 static void
 983 cifs_cancelled_callback(struct mid_q_entry *mid)
 984 {
 985         cifs_compound_callback(mid);
 986         DeleteMidQEntry(mid);
 987 }
 988
 989 int
 990 compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 991                    const int flags, const int num_rqst, struct smb_rqst *rqst,
 992                    int *resp_buf_type, struct kvec *resp_iov)
 993 {
 994         int i, j, optype, rc = 0;
 995         struct mid_q_entry *midQ[MAX_COMPOUND];
 996         bool cancelled_mid[MAX_COMPOUND] = {false};
 997         struct cifs_credits credits[MAX_COMPOUND] = {
 998                 { .value = 0, .instance = 0 }
 999         };
1000         unsigned int instance;
1001         char *buf;
1002         struct TCP_Server_Info *server;
1003
1004         optype = flags & CIFS_OP_MASK;
1005
1006         for (i = 0; i < num_rqst; i++)
1007                 resp_buf_type[i] = CIFS_NO_BUFFER;  /* no response buf yet */
1008
1009         if ((ses == NULL) || (ses->server == NULL)) {
1010                 cifs_dbg(VFS, "Null session\n");
1011                 return -EIO;
1012         }
1013
1014         server = ses->server;
1015         if (server->tcpStatus == CifsExiting)
1016                 return -ENOENT;
1017
1018         /*
1019          * Wait for all the requests to become available.
1020          * This approach still leaves the possibility to be stuck waiting for
1021          * credits if the server doesn't grant credits to the outstanding
1022          * requests and if the client is completely idle, not generating any
1023          * other requests.
1024          * This can be handled by the eventual session reconnect.
1025          */
1026         rc = wait_for_compound_request(server, num_rqst, flags,
1027                                        &instance);
1028         if (rc)
1029                 return rc;
1030
1031         for (i = 0; i < num_rqst; i++) {
1032                 credits[i].value = 1;
1033                 credits[i].instance = instance;
1034         }
1035
1036         /*
1037          * Make sure that we sign in the same order that we send on this socket
1038          * and avoid races inside tcp sendmsg code that could cause corruption
1039          * of smb data.
1040          */
1041
1042         mutex_lock(&server->srv_mutex);
1043
1044         /*
1045          * All the parts of the compound chain belong obtained credits from the
1046          * same session. We can not use credits obtained from the previous
1047          * session to send this request. Check if there were reconnects after
1048          * we obtained credits and return -EAGAIN in such cases to let callers
1049          * handle it.
1050          */
1051         if (instance != server->reconnect_instance) {
1052                 mutex_unlock(&server->srv_mutex);
1053                 for (j = 0; j < num_rqst; j++)
1054                         add_credits(server, &credits[j], optype);
1055                 return -EAGAIN;
1056         }
1057
1058         for (i = 0; i < num_rqst; i++) {
1059                 midQ[i] = server->ops->setup_request(ses, &rqst[i]);
1060                 if (IS_ERR(midQ[i])) {
1061                         revert_current_mid(server, i);
1062                         for (j = 0; j < i; j++)
1063                                 cifs_delete_mid(midQ[j]);
1064                         mutex_unlock(&server->srv_mutex);
1065
1066                         /* Update # of requests on wire to server */
1067                         for (j = 0; j < num_rqst; j++)
1068                                 add_credits(server, &credits[j], optype);
1069                         return PTR_ERR(midQ[i]);
1070                 }
1071
1072                 midQ[i]->mid_state = MID_REQUEST_SUBMITTED;
1073                 midQ[i]->optype = optype;
1074                 /*
1075                  * Invoke callback for every part of the compound chain
1076                  * to calculate credits properly. Wake up this thread only when
1077                  * the last element is received.
1078                  */
1079                 if (i < num_rqst - 1)
1080                         midQ[i]->callback = cifs_compound_callback;
1081                 else
1082                         midQ[i]->callback = cifs_compound_last_callback;
1083         }
1084         cifs_in_send_inc(server);
1085         rc = smb_send_rqst(server, num_rqst, rqst, flags);
1086         cifs_in_send_dec(server);
1087
1088         for (i = 0; i < num_rqst; i++)
1089                 cifs_save_when_sent(midQ[i]);
1090
1091         if (rc < 0) {
1092                 revert_current_mid(server, num_rqst);
1093                 server->sequence_number -= 2;
1094         }
1095
1096         mutex_unlock(&server->srv_mutex);
1097
1098         /*
1099          * If sending failed for some reason or it is an oplock break that we
1100          * will not receive a response to - return credits back
1101          */
1102         if (rc < 0 || (flags & CIFS_NO_SRV_RSP)) {
1103                 for (i = 0; i < num_rqst; i++)
1104                         add_credits(server, &credits[i], optype);
1105                 goto out;
1106         }
1107
1108         /*
1109          * At this point the request is passed to the network stack - we assume
1110          * that any credits taken from the server structure on the client have
1111          * been spent and we can't return them back. Once we receive responses
1112          * we will collect credits granted by the server in the mid callbacks
1113          * and add those credits to the server structure.
1114          */
1115
1116         /*
1117          * Compounding is never used during session establish.
1118          */
1119         if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP))
1120                 smb311_update_preauth_hash(ses, rqst[0].rq_iov,
1121                                            rqst[0].rq_nvec);
1122
1123         for (i = 0; i < num_rqst; i++) {
1124                 rc = wait_for_response(server, midQ[i]);
1125                 if (rc != 0)
1126                         break;
1127         }
1128         if (rc != 0) {
1129                 for (; i < num_rqst; i++) {
1130                         cifs_server_dbg(VFS, "Cancelling wait for mid %llu cmd: %d\n",
1131                                  midQ[i]->mid, le16_to_cpu(midQ[i]->command));
1132                         send_cancel(server, &rqst[i], midQ[i]);
1133                         spin_lock(&GlobalMid_Lock);
1134                         midQ[i]->mid_flags |= MID_WAIT_CANCELLED;
1135                         if (midQ[i]->mid_state == MID_REQUEST_SUBMITTED) {
1136                                 midQ[i]->callback = cifs_cancelled_callback;
1137                                 cancelled_mid[i] = true;
1138                                 credits[i].value = 0;
1139                         }
1140                         spin_unlock(&GlobalMid_Lock);
1141                 }
1142         }
1143
1144         for (i = 0; i < num_rqst; i++) {
1145                 if (rc < 0)
1146                         goto out;
1147
1148                 rc = cifs_sync_mid_result(midQ[i], server);
1149                 if (rc != 0) {
1150                         /* mark this mid as cancelled to not free it below */
1151                         cancelled_mid[i] = true;
1152                         goto out;
1153                 }
1154
1155                 if (!midQ[i]->resp_buf ||
1156                     midQ[i]->mid_state != MID_RESPONSE_RECEIVED) {
1157                         rc = -EIO;
1158                         cifs_dbg(FYI, "Bad MID state?\n");
1159                         goto out;
1160                 }
1161
1162                 buf = (char *)midQ[i]->resp_buf;
1163                 resp_iov[i].iov_base = buf;
1164                 resp_iov[i].iov_len = midQ[i]->resp_buf_size +
1165                         server->vals->header_preamble_size;
1166
1167                 if (midQ[i]->large_buf)
1168                         resp_buf_type[i] = CIFS_LARGE_BUFFER;
1169                 else
1170                         resp_buf_type[i] = CIFS_SMALL_BUFFER;
1171
1172                 rc = server->ops->check_receive(midQ[i], server,
1173                                                      flags & CIFS_LOG_ERROR);
1174
1175                 /* mark it so buf will not be freed by cifs_delete_mid */
1176                 if ((flags & CIFS_NO_RSP_BUF) == 0)
1177                         midQ[i]->resp_buf = NULL;
1178
1179         }
1180
1181         /*
1182          * Compounding is never used during session establish.
1183          */
1184         if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP)) {
1185                 struct kvec iov = {
1186                         .iov_base = resp_iov[0].iov_base,
1187                         .iov_len = resp_iov[0].iov_len
1188                 };
1189                 smb311_update_preauth_hash(ses, &iov, 1);
1190         }
1191
1192 out:
1193         /*
1194          * This will dequeue all mids. After this it is important that the
1195          * demultiplex_thread will not process any of these mids any futher.
1196          * This is prevented above by using a noop callback that will not
1197          * wake this thread except for the very last PDU.
1198          */
1199         for (i = 0; i < num_rqst; i++) {
1200                 if (!cancelled_mid[i])
1201                         cifs_delete_mid(midQ[i]);
1202         }
1203
1204         return rc;
1205 }
1206
1207 int
1208 cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
1209                struct smb_rqst *rqst, int *resp_buf_type, const int flags,
1210                struct kvec *resp_iov)
1211 {
1212         return compound_send_recv(xid, ses, flags, 1, rqst, resp_buf_type,
1213                                   resp_iov);
1214 }
1215
1216 int
1217 SendReceive2(const unsigned int xid, struct cifs_ses *ses,
1218              struct kvec *iov, int n_vec, int *resp_buf_type /* ret */,
1219              const int flags, struct kvec *resp_iov)
1220 {
1221         struct smb_rqst rqst;
1222         struct kvec s_iov[CIFS_MAX_IOV_SIZE], *new_iov;
1223         int rc;
1224
1225         if (n_vec + 1 > CIFS_MAX_IOV_SIZE) {
1226                 new_iov = kmalloc_array(n_vec + 1, sizeof(struct kvec),
1227                                         GFP_KERNEL);
1228                 if (!new_iov) {
1229                         /* otherwise cifs_send_recv below sets resp_buf_type */
1230                         *resp_buf_type = CIFS_NO_BUFFER;
1231                         return -ENOMEM;
1232                 }
1233         } else
1234                 new_iov = s_iov;
1235
1236         /* 1st iov is a RFC1001 length followed by the rest of the packet */
1237         memcpy(new_iov + 1, iov, (sizeof(struct kvec) * n_vec));
1238
1239         new_iov[0].iov_base = new_iov[1].iov_base;
1240         new_iov[0].iov_len = 4;
1241         new_iov[1].iov_base += 4;
1242         new_iov[1].iov_len -= 4;
1243
1244         memset(&rqst, 0, sizeof(struct smb_rqst));
1245         rqst.rq_iov = new_iov;
1246         rqst.rq_nvec = n_vec + 1;
1247
1248         rc = cifs_send_recv(xid, ses, &rqst, resp_buf_type, flags, resp_iov);
1249         if (n_vec + 1 > CIFS_MAX_IOV_SIZE)
1250                 kfree(new_iov);
1251         return rc;
1252 }
1253
1254 int
1255 SendReceive(const unsigned int xid, struct cifs_ses *ses,
1256             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
1257             int *pbytes_returned, const int flags)
1258 {
1259         int rc = 0;
1260         struct mid_q_entry *midQ;
1261         unsigned int len = be32_to_cpu(in_buf->smb_buf_length);
1262         struct kvec iov = { .iov_base = in_buf, .iov_len = len };
1263         struct smb_rqst rqst = { .rq_iov = &iov, .rq_nvec = 1 };
1264         struct cifs_credits credits = { .value = 1, .instance = 0 };
1265         struct TCP_Server_Info *server;
1266
1267         if (ses == NULL) {
1268                 cifs_dbg(VFS, "Null smb session\n");
1269                 return -EIO;
1270         }
1271         server = ses->server;
1272         if (server == NULL) {
1273                 cifs_dbg(VFS, "Null tcp session\n");
1274                 return -EIO;
1275         }
1276
1277         if (server->tcpStatus == CifsExiting)
1278                 return -ENOENT;
1279
1280         /* Ensure that we do not send more than 50 overlapping requests
1281            to the same server. We may make this configurable later or
1282            use ses->maxReq */
1283
1284         if (len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
1285                 cifs_server_dbg(VFS, "Illegal length, greater than maximum frame, %d\n",
1286                          len);
1287                 return -EIO;
1288         }
1289
1290         rc = wait_for_free_request(server, flags, &credits.instance);
1291         if (rc)
1292                 return rc;
1293
1294         /* make sure that we sign in the same order that we send on this socket
1295            and avoid races inside tcp sendmsg code that could cause corruption
1296            of smb data */
1297
1298         mutex_lock(&server->srv_mutex);
1299
1300         rc = allocate_mid(ses, in_buf, &midQ);
1301         if (rc) {
1302                 mutex_unlock(&ses->server->srv_mutex);
1303                 /* Update # of requests on wire to server */
1304                 add_credits(server, &credits, 0);
1305                 return rc;
1306         }
1307
1308         rc = cifs_sign_smb(in_buf, server, &midQ->sequence_number);
1309         if (rc) {
1310                 mutex_unlock(&server->srv_mutex);
1311                 goto out;
1312         }
1313
1314         midQ->mid_state = MID_REQUEST_SUBMITTED;
1315
1316         cifs_in_send_inc(server);
1317         rc = smb_send(server, in_buf, len);
1318         cifs_in_send_dec(server);
1319         cifs_save_when_sent(midQ);
1320
1321         if (rc < 0)
1322                 server->sequence_number -= 2;
1323
1324         mutex_unlock(&server->srv_mutex);
1325
1326         if (rc < 0)
1327                 goto out;
1328
1329         rc = wait_for_response(server, midQ);
1330         if (rc != 0) {
1331                 send_cancel(server, &rqst, midQ);
1332                 spin_lock(&GlobalMid_Lock);
1333                 if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
1334                         /* no longer considered to be "in-flight" */
1335                         midQ->callback = DeleteMidQEntry;
1336                         spin_unlock(&GlobalMid_Lock);
1337                         add_credits(server, &credits, 0);
1338                         return rc;
1339                 }
1340                 spin_unlock(&GlobalMid_Lock);
1341         }
1342
1343         rc = cifs_sync_mid_result(midQ, server);
1344         if (rc != 0) {
1345                 add_credits(server, &credits, 0);
1346                 return rc;
1347         }
1348
1349         if (!midQ->resp_buf || !out_buf ||
1350             midQ->mid_state != MID_RESPONSE_RECEIVED) {
1351                 rc = -EIO;
1352                 cifs_server_dbg(VFS, "Bad MID state?\n");
1353                 goto out;
1354         }
1355
1356         *pbytes_returned = get_rfc1002_length(midQ->resp_buf);
1357         memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
1358         rc = cifs_check_receive(midQ, server, 0);
1359 out:
1360         cifs_delete_mid(midQ);
1361         add_credits(server, &credits, 0);
1362
1363         return rc;
1364 }
1365
1366 /* We send a LOCKINGX_CANCEL_LOCK to cause the Windows
1367    blocking lock to return. */
1368
1369 static int
1370 send_lock_cancel(const unsigned int xid, struct cifs_tcon *tcon,
1371                         struct smb_hdr *in_buf,
1372                         struct smb_hdr *out_buf)
1373 {
1374         int bytes_returned;
1375         struct cifs_ses *ses = tcon->ses;
1376         LOCK_REQ *pSMB = (LOCK_REQ *)in_buf;
1377
1378         /* We just modify the current in_buf to change
1379            the type of lock from LOCKING_ANDX_SHARED_LOCK
1380            or LOCKING_ANDX_EXCLUSIVE_LOCK to
1381            LOCKING_ANDX_CANCEL_LOCK. */
1382
1383         pSMB->LockType = LOCKING_ANDX_CANCEL_LOCK|LOCKING_ANDX_LARGE_FILES;
1384         pSMB->Timeout = 0;
1385         pSMB->hdr.Mid = get_next_mid(ses->server);
1386
1387         return SendReceive(xid, ses, in_buf, out_buf,
1388                         &bytes_returned, 0);
1389 }
1390
1391 int
1392 SendReceiveBlockingLock(const unsigned int xid, struct cifs_tcon *tcon,
1393             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
1394             int *pbytes_returned)
1395 {
1396         int rc = 0;
1397         int rstart = 0;
1398         struct mid_q_entry *midQ;
1399         struct cifs_ses *ses;
1400         unsigned int len = be32_to_cpu(in_buf->smb_buf_length);
1401         struct kvec iov = { .iov_base = in_buf, .iov_len = len };
1402         struct smb_rqst rqst = { .rq_iov = &iov, .rq_nvec = 1 };
1403         unsigned int instance;
1404         struct TCP_Server_Info *server;
1405
1406         if (tcon == NULL || tcon->ses == NULL) {
1407                 cifs_dbg(VFS, "Null smb session\n");
1408                 return -EIO;
1409         }
1410         ses = tcon->ses;
1411         server = ses->server;
1412
1413         if (server == NULL) {
1414                 cifs_dbg(VFS, "Null tcp session\n");
1415                 return -EIO;
1416         }
1417
1418         if (server->tcpStatus == CifsExiting)
1419                 return -ENOENT;
1420
1421         /* Ensure that we do not send more than 50 overlapping requests
1422            to the same server. We may make this configurable later or
1423            use ses->maxReq */
1424
1425         if (len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
1426                 cifs_tcon_dbg(VFS, "Illegal length, greater than maximum frame, %d\n",
1427                          len);
1428                 return -EIO;
1429         }
1430
1431         rc = wait_for_free_request(server, CIFS_BLOCKING_OP, &instance);
1432         if (rc)
1433                 return rc;
1434
1435         /* make sure that we sign in the same order that we send on this socket
1436            and avoid races inside tcp sendmsg code that could cause corruption
1437            of smb data */
1438
1439         mutex_lock(&server->srv_mutex);
1440
1441         rc = allocate_mid(ses, in_buf, &midQ);
1442         if (rc) {
1443                 mutex_unlock(&server->srv_mutex);
1444                 return rc;
1445         }
1446
1447         rc = cifs_sign_smb(in_buf, server, &midQ->sequence_number);
1448         if (rc) {
1449                 cifs_delete_mid(midQ);
1450                 mutex_unlock(&server->srv_mutex);
1451                 return rc;
1452         }
1453
1454         midQ->mid_state = MID_REQUEST_SUBMITTED;
1455         cifs_in_send_inc(server);
1456         rc = smb_send(server, in_buf, len);
1457         cifs_in_send_dec(server);
1458         cifs_save_when_sent(midQ);
1459
1460         if (rc < 0)
1461                 server->sequence_number -= 2;
1462
1463         mutex_unlock(&server->srv_mutex);
1464
1465         if (rc < 0) {
1466                 cifs_delete_mid(midQ);
1467                 return rc;
1468         }
1469
1470         /* Wait for a reply - allow signals to interrupt. */
1471         rc = wait_event_interruptible(server->response_q,
1472                 (!(midQ->mid_state == MID_REQUEST_SUBMITTED)) ||
1473                 ((server->tcpStatus != CifsGood) &&
1474                  (server->tcpStatus != CifsNew)));
1475
1476         /* Were we interrupted by a signal ? */
1477         if ((rc == -ERESTARTSYS) &&
1478                 (midQ->mid_state == MID_REQUEST_SUBMITTED) &&
1479                 ((server->tcpStatus == CifsGood) ||
1480                  (server->tcpStatus == CifsNew))) {
1481
1482                 if (in_buf->Command == SMB_COM_TRANSACTION2) {
1483                         /* POSIX lock. We send a NT_CANCEL SMB to cause the
1484                            blocking lock to return. */
1485                         rc = send_cancel(server, &rqst, midQ);
1486                         if (rc) {
1487                                 cifs_delete_mid(midQ);
1488                                 return rc;
1489                         }
1490                 } else {
1491                         /* Windows lock. We send a LOCKINGX_CANCEL_LOCK
1492                            to cause the blocking lock to return. */
1493
1494                         rc = send_lock_cancel(xid, tcon, in_buf, out_buf);
1495
1496                         /* If we get -ENOLCK back the lock may have
1497                            already been removed. Don't exit in this case. */
1498                         if (rc && rc != -ENOLCK) {
1499                                 cifs_delete_mid(midQ);
1500                                 return rc;
1501                         }
1502                 }
1503
1504                 rc = wait_for_response(server, midQ);
1505                 if (rc) {
1506                         send_cancel(server, &rqst, midQ);
1507                         spin_lock(&GlobalMid_Lock);
1508                         if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
1509                                 /* no longer considered to be "in-flight" */
1510                                 midQ->callback = DeleteMidQEntry;
1511                                 spin_unlock(&GlobalMid_Lock);
1512                                 return rc;
1513                         }
1514                         spin_unlock(&GlobalMid_Lock);
1515                 }
1516
1517                 /* We got the response - restart system call. */
1518                 rstart = 1;
1519         }
1520
1521         rc = cifs_sync_mid_result(midQ, server);
1522         if (rc != 0)
1523                 return rc;
1524
1525         /* rcvd frame is ok */
1526         if (out_buf == NULL || midQ->mid_state != MID_RESPONSE_RECEIVED) {
1527                 rc = -EIO;
1528                 cifs_tcon_dbg(VFS, "Bad MID state?\n");
1529                 goto out;
1530         }
1531
1532         *pbytes_returned = get_rfc1002_length(midQ->resp_buf);
1533         memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
1534         rc = cifs_check_receive(midQ, server, 0);
1535 out:
1536         cifs_delete_mid(midQ);
1537         if (rstart && rc == -EACCES)
1538                 return -ERESTARTSYS;
1539         return rc;
1540 }