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("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         __be32 rfc1002_marker;
 329
 330         if (cifs_rdma_enabled(server)) {
 331                 /* return -EAGAIN when connecting or reconnecting */
 332                 rc = -EAGAIN;
 333                 if (server->smbd_conn)
 334                         rc = smbd_send(server, num_rqst, rqst);
 335                 goto smbd_done;
 336         }
 337
 338         if (ssocket == NULL)
 339                 return -EAGAIN;
 340
 341         if (signal_pending(current)) {
 342                 cifs_dbg(FYI, "signal pending before send request\n");
 343                 return -ERESTARTSYS;
 344         }
 345
 346         /* cork the socket */
 347         tcp_sock_set_cork(ssocket->sk, true);
 348
 349         for (j = 0; j < num_rqst; j++)
 350                 send_length += smb_rqst_len(server, &rqst[j]);
 351         rfc1002_marker = cpu_to_be32(send_length);
 352
 353         /*
 354          * We should not allow signals to interrupt the network send because
 355          * any partial send will cause session reconnects thus increasing
 356          * latency of system calls and overload a server with unnecessary
 357          * requests.
 358          */
 359
 360         sigfillset(&mask);
 361         sigprocmask(SIG_BLOCK, &mask, &oldmask);
 362
 363         /* Generate a rfc1002 marker for SMB2+ */
 364         if (server->vals->header_preamble_size == 0) {
 365                 struct kvec hiov = {
 366                         .iov_base = &rfc1002_marker,
 367                         .iov_len  = 4
 368                 };
 369                 iov_iter_kvec(&smb_msg.msg_iter, WRITE, &hiov, 1, 4);
 370                 rc = smb_send_kvec(server, &smb_msg, &sent);
 371                 if (rc < 0)
 372                         goto unmask;
 373
 374                 total_len += sent;
 375                 send_length += 4;
 376         }
 377
 378         cifs_dbg(FYI, "Sending smb: smb_len=%u\n", send_length);
 379
 380         for (j = 0; j < num_rqst; j++) {
 381                 iov = rqst[j].rq_iov;
 382                 n_vec = rqst[j].rq_nvec;
 383
 384                 size = 0;
 385                 for (i = 0; i < n_vec; i++) {
 386                         dump_smb(iov[i].iov_base, iov[i].iov_len);
 387                         size += iov[i].iov_len;
 388                 }
 389
 390                 iov_iter_kvec(&smb_msg.msg_iter, WRITE, iov, n_vec, size);
 391
 392                 rc = smb_send_kvec(server, &smb_msg, &sent);
 393                 if (rc < 0)
 394                         goto unmask;
 395
 396                 total_len += sent;
 397
 398                 /* now walk the page array and send each page in it */
 399                 for (i = 0; i < rqst[j].rq_npages; i++) {
 400                         struct bio_vec bvec;
 401
 402                         bvec.bv_page = rqst[j].rq_pages[i];
 403                         rqst_page_get_length(&rqst[j], i, &bvec.bv_len,
 404                                              &bvec.bv_offset);
 405
 406                         iov_iter_bvec(&smb_msg.msg_iter, WRITE,
 407                                       &bvec, 1, bvec.bv_len);
 408                         rc = smb_send_kvec(server, &smb_msg, &sent);
 409                         if (rc < 0)
 410                                 break;
 411
 412                         total_len += sent;
 413                 }
 414         }
 415
 416 unmask:
 417         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 418
 419         /*
 420          * If signal is pending but we have already sent the whole packet to
 421          * the server we need to return success status to allow a corresponding
 422          * mid entry to be kept in the pending requests queue thus allowing
 423          * to handle responses from the server by the client.
 424          *
 425          * If only part of the packet has been sent there is no need to hide
 426          * interrupt because the session will be reconnected anyway, so there
 427          * won't be any response from the server to handle.
 428          */
 429
 430         if (signal_pending(current) && (total_len != send_length)) {
 431                 cifs_dbg(FYI, "signal is pending after attempt to send\n");
 432                 rc = -EINTR;
 433         }
 434
 435         /* uncork it */
 436         tcp_sock_set_cork(ssocket->sk, false);
 437
 438         if ((total_len > 0) && (total_len != send_length)) {
 439                 cifs_dbg(FYI, "partial send (wanted=%u sent=%zu): terminating session\n",
 440                          send_length, total_len);
 441                 /*
 442                  * If we have only sent part of an SMB then the next SMB could
 443                  * be taken as the remainder of this one. We need to kill the
 444                  * socket so the server throws away the partial SMB
 445                  */
 446                 server->tcpStatus = CifsNeedReconnect;
 447                 trace_smb3_partial_send_reconnect(server->CurrentMid,
 448                                                   server->hostname);
 449         }
 450 smbd_done:
 451         if (rc < 0 && rc != -EINTR)
 452                 cifs_server_dbg(VFS, "Error %d sending data on socket to server\n",
 453                          rc);
 454         else if (rc > 0)
 455                 rc = 0;
 456
 457         return rc;
 458 }
 459
 460 static int
 461 smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 462               struct smb_rqst *rqst, int flags)
 463 {
 464         struct kvec iov;
 465         struct smb2_transform_hdr *tr_hdr;
 466         struct smb_rqst cur_rqst[MAX_COMPOUND];
 467         int rc;
 468
 469         if (!(flags & CIFS_TRANSFORM_REQ))
 470                 return __smb_send_rqst(server, num_rqst, rqst);
 471
 472         if (num_rqst > MAX_COMPOUND - 1)
 473                 return -ENOMEM;
 474
 475         if (!server->ops->init_transform_rq) {
 476                 cifs_server_dbg(VFS, "Encryption requested but transform callback is missing\n");
 477                 return -EIO;
 478         }
 479
 480         tr_hdr = kmalloc(sizeof(*tr_hdr), GFP_NOFS);
 481         if (!tr_hdr)
 482                 return -ENOMEM;
 483
 484         memset(&cur_rqst[0], 0, sizeof(cur_rqst));
 485         memset(&iov, 0, sizeof(iov));
 486         memset(tr_hdr, 0, sizeof(*tr_hdr));
 487
 488         iov.iov_base = tr_hdr;
 489         iov.iov_len = sizeof(*tr_hdr);
 490         cur_rqst[0].rq_iov = &iov;
 491         cur_rqst[0].rq_nvec = 1;
 492
 493         rc = server->ops->init_transform_rq(server, num_rqst + 1,
 494                                             &cur_rqst[0], rqst);
 495         if (rc)
 496                 goto out;
 497
 498         rc = __smb_send_rqst(server, num_rqst + 1, &cur_rqst[0]);
 499         smb3_free_compound_rqst(num_rqst, &cur_rqst[1]);
 500 out:
 501         kfree(tr_hdr);
 502         return rc;
 503 }
 504
 505 int
 506 smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
 507          unsigned int smb_buf_length)
 508 {
 509         struct kvec iov[2];
 510         struct smb_rqst rqst = { .rq_iov = iov,
 511                                  .rq_nvec = 2 };
 512
 513         iov[0].iov_base = smb_buffer;
 514         iov[0].iov_len = 4;
 515         iov[1].iov_base = (char *)smb_buffer + 4;
 516         iov[1].iov_len = smb_buf_length;
 517
 518         return __smb_send_rqst(server, 1, &rqst);
 519 }
 520
 521 static int
 522 wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits,
 523                       const int timeout, const int flags,
 524                       unsigned int *instance)
 525 {
 526         long rc;
 527         int *credits;
 528         int optype;
 529         long int t;
 530         int scredits = server->credits;
 531
 532         if (timeout < 0)
 533                 t = MAX_JIFFY_OFFSET;
 534         else
 535                 t = msecs_to_jiffies(timeout);
 536
 537         optype = flags & CIFS_OP_MASK;
 538
 539         *instance = 0;
 540
 541         credits = server->ops->get_credits_field(server, optype);
 542         /* Since an echo is already inflight, no need to wait to send another */
 543         if (*credits <= 0 && optype == CIFS_ECHO_OP)
 544                 return -EAGAIN;
 545
 546         spin_lock(&server->req_lock);
 547         if ((flags & CIFS_TIMEOUT_MASK) == CIFS_NON_BLOCKING) {
 548                 /* oplock breaks must not be held up */
 549                 server->in_flight++;
 550                 if (server->in_flight > server->max_in_flight)
 551                         server->max_in_flight = server->in_flight;
 552                 *credits -= 1;
 553                 *instance = server->reconnect_instance;
 554                 spin_unlock(&server->req_lock);
 555                 return 0;
 556         }
 557
 558         while (1) {
 559                 if (*credits < num_credits) {
 560                         spin_unlock(&server->req_lock);
 561                         cifs_num_waiters_inc(server);
 562                         rc = wait_event_killable_timeout(server->request_q,
 563                                 has_credits(server, credits, num_credits), t);
 564                         cifs_num_waiters_dec(server);
 565                         if (!rc) {
 566                                 trace_smb3_credit_timeout(server->CurrentMid,
 567                                         server->hostname, num_credits, 0);
 568                                 cifs_server_dbg(VFS, "wait timed out after %d ms\n",
 569                                          timeout);
 570                                 return -ENOTSUPP;
 571                         }
 572                         if (rc == -ERESTARTSYS)
 573                                 return -ERESTARTSYS;
 574                         spin_lock(&server->req_lock);
 575                 } else {
 576                         if (server->tcpStatus == CifsExiting) {
 577                                 spin_unlock(&server->req_lock);
 578                                 return -ENOENT;
 579                         }
 580
 581                         /*
 582                          * For normal commands, reserve the last MAX_COMPOUND
 583                          * credits to compound requests.
 584                          * Otherwise these compounds could be permanently
 585                          * starved for credits by single-credit requests.
 586                          *
 587                          * To prevent spinning CPU, block this thread until
 588                          * there are >MAX_COMPOUND credits available.
 589                          * But only do this is we already have a lot of
 590                          * credits in flight to avoid triggering this check
 591                          * for servers that are slow to hand out credits on
 592                          * new sessions.
 593                          */
 594                         if (!optype && num_credits == 1 &&
 595                             server->in_flight > 2 * MAX_COMPOUND &&
 596                             *credits <= MAX_COMPOUND) {
 597                                 spin_unlock(&server->req_lock);
 598                                 cifs_num_waiters_inc(server);
 599                                 rc = wait_event_killable_timeout(
 600                                         server->request_q,
 601                                         has_credits(server, credits,
 602                                                     MAX_COMPOUND + 1),
 603                                         t);
 604                                 cifs_num_waiters_dec(server);
 605                                 if (!rc) {
 606                                         trace_smb3_credit_timeout(
 607                                                 server->CurrentMid,
 608                                                 server->hostname, num_credits,
 609                                                 0);
 610                                         cifs_server_dbg(VFS, "wait timed out after %d ms\n",
 611                                                  timeout);
 612                                         return -ENOTSUPP;
 613                                 }
 614                                 if (rc == -ERESTARTSYS)
 615                                         return -ERESTARTSYS;
 616                                 spin_lock(&server->req_lock);
 617                                 continue;
 618                         }
 619
 620                         /*
 621                          * Can not count locking commands against total
 622                          * as they are allowed to block on server.
 623                          */
 624
 625                         /* update # of requests on the wire to server */
 626                         if ((flags & CIFS_TIMEOUT_MASK) != CIFS_BLOCKING_OP) {
 627                                 *credits -= num_credits;
 628                                 scredits = *credits;
 629                                 server->in_flight += num_credits;
 630                                 if (server->in_flight > server->max_in_flight)
 631                                         server->max_in_flight = server->in_flight;
 632                                 *instance = server->reconnect_instance;
 633                         }
 634                         spin_unlock(&server->req_lock);
 635
 636                         trace_smb3_add_credits(server->CurrentMid,
 637                                         server->hostname, scredits, -(num_credits));
 638                         cifs_dbg(FYI, "%s: remove %u credits total=%d\n",
 639                                         __func__, num_credits, scredits);
 640                         break;
 641                 }
 642         }
 643         return 0;
 644 }
 645
 646 static int
 647 wait_for_free_request(struct TCP_Server_Info *server, const int flags,
 648                       unsigned int *instance)
 649 {
 650         return wait_for_free_credits(server, 1, -1, flags,
 651                                      instance);
 652 }
 653
 654 static int
 655 wait_for_compound_request(struct TCP_Server_Info *server, int num,
 656                           const int flags, unsigned int *instance)
 657 {
 658         int *credits;
 659         int scredits, sin_flight;
 660
 661         credits = server->ops->get_credits_field(server, flags & CIFS_OP_MASK);
 662
 663         spin_lock(&server->req_lock);
 664         scredits = *credits;
 665         sin_flight = server->in_flight;
 666
 667         if (*credits < num) {
 668                 /*
 669                  * Return immediately if not too many requests in flight since
 670                  * we will likely be stuck on waiting for credits.
 671                  */
 672                 if (server->in_flight < num - *credits) {
 673                         spin_unlock(&server->req_lock);
 674                         trace_smb3_insufficient_credits(server->CurrentMid,
 675                                         server->hostname, scredits, sin_flight);
 676                         cifs_dbg(FYI, "%s: %d requests in flight, needed %d total=%d\n",
 677                                         __func__, sin_flight, num, scredits);
 678                         return -ENOTSUPP;
 679                 }
 680         }
 681         spin_unlock(&server->req_lock);
 682
 683         return wait_for_free_credits(server, num, 60000, flags,
 684                                      instance);
 685 }
 686
 687 int
 688 cifs_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size,
 689                       unsigned int *num, struct cifs_credits *credits)
 690 {
 691         *num = size;
 692         credits->value = 0;
 693         credits->instance = server->reconnect_instance;
 694         return 0;
 695 }
 696
 697 static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,
 698                         struct mid_q_entry **ppmidQ)
 699 {
 700         if (ses->server->tcpStatus == CifsExiting) {
 701                 return -ENOENT;
 702         }
 703
 704         if (ses->server->tcpStatus == CifsNeedReconnect) {
 705                 cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
 706                 return -EAGAIN;
 707         }
 708
 709         if (ses->status == CifsNew) {
 710                 if ((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
 711                         (in_buf->Command != SMB_COM_NEGOTIATE))
 712                         return -EAGAIN;
 713                 /* else ok - we are setting up session */
 714         }
 715
 716         if (ses->status == CifsExiting) {
 717                 /* check if SMB session is bad because we are setting it up */
 718                 if (in_buf->Command != SMB_COM_LOGOFF_ANDX)
 719                         return -EAGAIN;
 720                 /* else ok - we are shutting down session */
 721         }
 722
 723         *ppmidQ = AllocMidQEntry(in_buf, ses->server);
 724         if (*ppmidQ == NULL)
 725                 return -ENOMEM;
 726         spin_lock(&GlobalMid_Lock);
 727         list_add_tail(&(*ppmidQ)->qhead, &ses->server->pending_mid_q);
 728         spin_unlock(&GlobalMid_Lock);
 729         return 0;
 730 }
 731
 732 static int
 733 wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
 734 {
 735         int error;
 736
 737         error = wait_event_freezekillable_unsafe(server->response_q,
 738                                     midQ->mid_state != MID_REQUEST_SUBMITTED);
 739         if (error < 0)
 740                 return -ERESTARTSYS;
 741
 742         return 0;
 743 }
 744
 745 struct mid_q_entry *
 746 cifs_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 747 {
 748         int rc;
 749         struct smb_hdr *hdr = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
 750         struct mid_q_entry *mid;
 751
 752         if (rqst->rq_iov[0].iov_len != 4 ||
 753             rqst->rq_iov[0].iov_base + 4 != rqst->rq_iov[1].iov_base)
 754                 return ERR_PTR(-EIO);
 755
 756         /* enable signing if server requires it */
 757         if (server->sign)
 758                 hdr->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 759
 760         mid = AllocMidQEntry(hdr, server);
 761         if (mid == NULL)
 762                 return ERR_PTR(-ENOMEM);
 763
 764         rc = cifs_sign_rqst(rqst, server, &mid->sequence_number);
 765         if (rc) {
 766                 DeleteMidQEntry(mid);
 767                 return ERR_PTR(rc);
 768         }
 769
 770         return mid;
 771 }
 772
 773 /*
 774  * Send a SMB request and set the callback function in the mid to handle
 775  * the result. Caller is responsible for dealing with timeouts.
 776  */
 777 int
 778 cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,
 779                 mid_receive_t *receive, mid_callback_t *callback,
 780                 mid_handle_t *handle, void *cbdata, const int flags,
 781                 const struct cifs_credits *exist_credits)
 782 {
 783         int rc;
 784         struct mid_q_entry *mid;
 785         struct cifs_credits credits = { .value = 0, .instance = 0 };
 786         unsigned int instance;
 787         int optype;
 788
 789         optype = flags & CIFS_OP_MASK;
 790
 791         if ((flags & CIFS_HAS_CREDITS) == 0) {
 792                 rc = wait_for_free_request(server, flags, &instance);
 793                 if (rc)
 794                         return rc;
 795                 credits.value = 1;
 796                 credits.instance = instance;
 797         } else
 798                 instance = exist_credits->instance;
 799
 800         mutex_lock(&server->srv_mutex);
 801
 802         /*
 803          * We can't use credits obtained from the previous session to send this
 804          * request. Check if there were reconnects after we obtained credits and
 805          * return -EAGAIN in such cases to let callers handle it.
 806          */
 807         if (instance != server->reconnect_instance) {
 808                 mutex_unlock(&server->srv_mutex);
 809                 add_credits_and_wake_if(server, &credits, optype);
 810                 return -EAGAIN;
 811         }
 812
 813         mid = server->ops->setup_async_request(server, rqst);
 814         if (IS_ERR(mid)) {
 815                 mutex_unlock(&server->srv_mutex);
 816                 add_credits_and_wake_if(server, &credits, optype);
 817                 return PTR_ERR(mid);
 818         }
 819
 820         mid->receive = receive;
 821         mid->callback = callback;
 822         mid->callback_data = cbdata;
 823         mid->handle = handle;
 824         mid->mid_state = MID_REQUEST_SUBMITTED;
 825
 826         /* put it on the pending_mid_q */
 827         spin_lock(&GlobalMid_Lock);
 828         list_add_tail(&mid->qhead, &server->pending_mid_q);
 829         spin_unlock(&GlobalMid_Lock);
 830
 831         /*
 832          * Need to store the time in mid before calling I/O. For call_async,
 833          * I/O response may come back and free the mid entry on another thread.
 834          */
 835         cifs_save_when_sent(mid);
 836         cifs_in_send_inc(server);
 837         rc = smb_send_rqst(server, 1, rqst, flags);
 838         cifs_in_send_dec(server);
 839
 840         if (rc < 0) {
 841                 revert_current_mid(server, mid->credits);
 842                 server->sequence_number -= 2;
 843                 cifs_delete_mid(mid);
 844         }
 845
 846         mutex_unlock(&server->srv_mutex);
 847
 848         if (rc == 0)
 849                 return 0;
 850
 851         add_credits_and_wake_if(server, &credits, optype);
 852         return rc;
 853 }
 854
 855 /*
 856  *
 857  * Send an SMB Request.  No response info (other than return code)
 858  * needs to be parsed.
 859  *
 860  * flags indicate the type of request buffer and how long to wait
 861  * and whether to log NT STATUS code (error) before mapping it to POSIX error
 862  *
 863  */
 864 int
 865 SendReceiveNoRsp(const unsigned int xid, struct cifs_ses *ses,
 866                  char *in_buf, int flags)
 867 {
 868         int rc;
 869         struct kvec iov[1];
 870         struct kvec rsp_iov;
 871         int resp_buf_type;
 872
 873         iov[0].iov_base = in_buf;
 874         iov[0].iov_len = get_rfc1002_length(in_buf) + 4;
 875         flags |= CIFS_NO_RSP_BUF;
 876         rc = SendReceive2(xid, ses, iov, 1, &resp_buf_type, flags, &rsp_iov);
 877         cifs_dbg(NOISY, "SendRcvNoRsp flags %d rc %d\n", flags, rc);
 878
 879         return rc;
 880 }
 881
 882 static int
 883 cifs_sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
 884 {
 885         int rc = 0;
 886
 887         cifs_dbg(FYI, "%s: cmd=%d mid=%llu state=%d\n",
 888                  __func__, le16_to_cpu(mid->command), mid->mid, mid->mid_state);
 889
 890         spin_lock(&GlobalMid_Lock);
 891         switch (mid->mid_state) {
 892         case MID_RESPONSE_RECEIVED:
 893                 spin_unlock(&GlobalMid_Lock);
 894                 return rc;
 895         case MID_RETRY_NEEDED:
 896                 rc = -EAGAIN;
 897                 break;
 898         case MID_RESPONSE_MALFORMED:
 899                 rc = -EIO;
 900                 break;
 901         case MID_SHUTDOWN:
 902                 rc = -EHOSTDOWN;
 903                 break;
 904         default:
 905                 if (!(mid->mid_flags & MID_DELETED)) {
 906                         list_del_init(&mid->qhead);
 907                         mid->mid_flags |= MID_DELETED;
 908                 }
 909                 cifs_server_dbg(VFS, "%s: invalid mid state mid=%llu state=%d\n",
 910                          __func__, mid->mid, mid->mid_state);
 911                 rc = -EIO;
 912         }
 913         spin_unlock(&GlobalMid_Lock);
 914
 915         DeleteMidQEntry(mid);
 916         return rc;
 917 }
 918
 919 static inline int
 920 send_cancel(struct TCP_Server_Info *server, struct smb_rqst *rqst,
 921             struct mid_q_entry *mid)
 922 {
 923         return server->ops->send_cancel ?
 924                                 server->ops->send_cancel(server, rqst, mid) : 0;
 925 }
 926
 927 int
 928 cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 929                    bool log_error)
 930 {
 931         unsigned int len = get_rfc1002_length(mid->resp_buf) + 4;
 932
 933         dump_smb(mid->resp_buf, min_t(u32, 92, len));
 934
 935         /* convert the length into a more usable form */
 936         if (server->sign) {
 937                 struct kvec iov[2];
 938                 int rc = 0;
 939                 struct smb_rqst rqst = { .rq_iov = iov,
 940                                          .rq_nvec = 2 };
 941
 942                 iov[0].iov_base = mid->resp_buf;
 943                 iov[0].iov_len = 4;
 944                 iov[1].iov_base = (char *)mid->resp_buf + 4;
 945                 iov[1].iov_len = len - 4;
 946                 /* FIXME: add code to kill session */
 947                 rc = cifs_verify_signature(&rqst, server,
 948                                            mid->sequence_number);
 949                 if (rc)
 950                         cifs_server_dbg(VFS, "SMB signature verification returned error = %d\n",
 951                                  rc);
 952         }
 953
 954         /* BB special case reconnect tid and uid here? */
 955         return map_and_check_smb_error(mid, log_error);
 956 }
 957
 958 struct mid_q_entry *
 959 cifs_setup_request(struct cifs_ses *ses, struct TCP_Server_Info *ignored,
 960                    struct smb_rqst *rqst)
 961 {
 962         int rc;
 963         struct smb_hdr *hdr = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
 964         struct mid_q_entry *mid;
 965
 966         if (rqst->rq_iov[0].iov_len != 4 ||
 967             rqst->rq_iov[0].iov_base + 4 != rqst->rq_iov[1].iov_base)
 968                 return ERR_PTR(-EIO);
 969
 970         rc = allocate_mid(ses, hdr, &mid);
 971         if (rc)
 972                 return ERR_PTR(rc);
 973         rc = cifs_sign_rqst(rqst, ses->server, &mid->sequence_number);
 974         if (rc) {
 975                 cifs_delete_mid(mid);
 976                 return ERR_PTR(rc);
 977         }
 978         return mid;
 979 }
 980
 981 static void
 982 cifs_compound_callback(struct mid_q_entry *mid)
 983 {
 984         struct TCP_Server_Info *server = mid->server;
 985         struct cifs_credits credits;
 986
 987         credits.value = server->ops->get_credits(mid);
 988         credits.instance = server->reconnect_instance;
 989
 990         add_credits(server, &credits, mid->optype);
 991 }
 992
 993 static void
 994 cifs_compound_last_callback(struct mid_q_entry *mid)
 995 {
 996         cifs_compound_callback(mid);
 997         cifs_wake_up_task(mid);
 998 }
 999
1000 static void
1001 cifs_cancelled_callback(struct mid_q_entry *mid)
1002 {
1003         cifs_compound_callback(mid);
1004         DeleteMidQEntry(mid);
1005 }
1006
1007 /*
1008  * Return a channel (master if none) of @ses that can be used to send
1009  * regular requests.
1010  *
1011  * If we are currently binding a new channel (negprot/sess.setup),
1012  * return the new incomplete channel.
1013  */
1014 struct TCP_Server_Info *cifs_pick_channel(struct cifs_ses *ses)
1015 {
1016         uint index = 0;
1017
1018         if (!ses)
1019                 return NULL;
1020
1021         if (!ses->binding) {
1022                 /* round robin */
1023                 if (ses->chan_count > 1) {
1024                         index = (uint)atomic_inc_return(&ses->chan_seq);
1025                         index %= ses->chan_count;
1026                 }
1027                 return ses->chans[index].server;
1028         } else {
1029                 return cifs_ses_server(ses);
1030         }
1031 }
1032
1033 int
1034 compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
1035                    struct TCP_Server_Info *server,
1036                    const int flags, const int num_rqst, struct smb_rqst *rqst,
1037                    int *resp_buf_type, struct kvec *resp_iov)
1038 {
1039         int i, j, optype, rc = 0;
1040         struct mid_q_entry *midQ[MAX_COMPOUND];
1041         bool cancelled_mid[MAX_COMPOUND] = {false};
1042         struct cifs_credits credits[MAX_COMPOUND] = {
1043                 { .value = 0, .instance = 0 }
1044         };
1045         unsigned int instance;
1046         char *buf;
1047
1048         optype = flags & CIFS_OP_MASK;
1049
1050         for (i = 0; i < num_rqst; i++)
1051                 resp_buf_type[i] = CIFS_NO_BUFFER;  /* no response buf yet */
1052
1053         if (!ses || !ses->server || !server) {
1054                 cifs_dbg(VFS, "Null session\n");
1055                 return -EIO;
1056         }
1057
1058         if (server->tcpStatus == CifsExiting)
1059                 return -ENOENT;
1060
1061         /*
1062          * Wait for all the requests to become available.
1063          * This approach still leaves the possibility to be stuck waiting for
1064          * credits if the server doesn't grant credits to the outstanding
1065          * requests and if the client is completely idle, not generating any
1066          * other requests.
1067          * This can be handled by the eventual session reconnect.
1068          */
1069         rc = wait_for_compound_request(server, num_rqst, flags,
1070                                        &instance);
1071         if (rc)
1072                 return rc;
1073
1074         for (i = 0; i < num_rqst; i++) {
1075                 credits[i].value = 1;
1076                 credits[i].instance = instance;
1077         }
1078
1079         /*
1080          * Make sure that we sign in the same order that we send on this socket
1081          * and avoid races inside tcp sendmsg code that could cause corruption
1082          * of smb data.
1083          */
1084
1085         mutex_lock(&server->srv_mutex);
1086
1087         /*
1088          * All the parts of the compound chain belong obtained credits from the
1089          * same session. We can not use credits obtained from the previous
1090          * session to send this request. Check if there were reconnects after
1091          * we obtained credits and return -EAGAIN in such cases to let callers
1092          * handle it.
1093          */
1094         if (instance != server->reconnect_instance) {
1095                 mutex_unlock(&server->srv_mutex);
1096                 for (j = 0; j < num_rqst; j++)
1097                         add_credits(server, &credits[j], optype);
1098                 return -EAGAIN;
1099         }
1100
1101         for (i = 0; i < num_rqst; i++) {
1102                 midQ[i] = server->ops->setup_request(ses, server, &rqst[i]);
1103                 if (IS_ERR(midQ[i])) {
1104                         revert_current_mid(server, i);
1105                         for (j = 0; j < i; j++)
1106                                 cifs_delete_mid(midQ[j]);
1107                         mutex_unlock(&server->srv_mutex);
1108
1109                         /* Update # of requests on wire to server */
1110                         for (j = 0; j < num_rqst; j++)
1111                                 add_credits(server, &credits[j], optype);
1112                         return PTR_ERR(midQ[i]);
1113                 }
1114
1115                 midQ[i]->mid_state = MID_REQUEST_SUBMITTED;
1116                 midQ[i]->optype = optype;
1117                 /*
1118                  * Invoke callback for every part of the compound chain
1119                  * to calculate credits properly. Wake up this thread only when
1120                  * the last element is received.
1121                  */
1122                 if (i < num_rqst - 1)
1123                         midQ[i]->callback = cifs_compound_callback;
1124                 else
1125                         midQ[i]->callback = cifs_compound_last_callback;
1126         }
1127         cifs_in_send_inc(server);
1128         rc = smb_send_rqst(server, num_rqst, rqst, flags);
1129         cifs_in_send_dec(server);
1130
1131         for (i = 0; i < num_rqst; i++)
1132                 cifs_save_when_sent(midQ[i]);
1133
1134         if (rc < 0) {
1135                 revert_current_mid(server, num_rqst);
1136                 server->sequence_number -= 2;
1137         }
1138
1139         mutex_unlock(&server->srv_mutex);
1140
1141         /*
1142          * If sending failed for some reason or it is an oplock break that we
1143          * will not receive a response to - return credits back
1144          */
1145         if (rc < 0 || (flags & CIFS_NO_SRV_RSP)) {
1146                 for (i = 0; i < num_rqst; i++)
1147                         add_credits(server, &credits[i], optype);
1148                 goto out;
1149         }
1150
1151         /*
1152          * At this point the request is passed to the network stack - we assume
1153          * that any credits taken from the server structure on the client have
1154          * been spent and we can't return them back. Once we receive responses
1155          * we will collect credits granted by the server in the mid callbacks
1156          * and add those credits to the server structure.
1157          */
1158
1159         /*
1160          * Compounding is never used during session establish.
1161          */
1162         if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP))
1163                 smb311_update_preauth_hash(ses, rqst[0].rq_iov,
1164                                            rqst[0].rq_nvec);
1165
1166         for (i = 0; i < num_rqst; i++) {
1167                 rc = wait_for_response(server, midQ[i]);
1168                 if (rc != 0)
1169                         break;
1170         }
1171         if (rc != 0) {
1172                 for (; i < num_rqst; i++) {
1173                         cifs_server_dbg(VFS, "Cancelling wait for mid %llu cmd: %d\n",
1174                                  midQ[i]->mid, le16_to_cpu(midQ[i]->command));
1175                         send_cancel(server, &rqst[i], midQ[i]);
1176                         spin_lock(&GlobalMid_Lock);
1177                         midQ[i]->mid_flags |= MID_WAIT_CANCELLED;
1178                         if (midQ[i]->mid_state == MID_REQUEST_SUBMITTED) {
1179                                 midQ[i]->callback = cifs_cancelled_callback;
1180                                 cancelled_mid[i] = true;
1181                                 credits[i].value = 0;
1182                         }
1183                         spin_unlock(&GlobalMid_Lock);
1184                 }
1185         }
1186
1187         for (i = 0; i < num_rqst; i++) {
1188                 if (rc < 0)
1189                         goto out;
1190
1191                 rc = cifs_sync_mid_result(midQ[i], server);
1192                 if (rc != 0) {
1193                         /* mark this mid as cancelled to not free it below */
1194                         cancelled_mid[i] = true;
1195                         goto out;
1196                 }
1197
1198                 if (!midQ[i]->resp_buf ||
1199                     midQ[i]->mid_state != MID_RESPONSE_RECEIVED) {
1200                         rc = -EIO;
1201                         cifs_dbg(FYI, "Bad MID state?\n");
1202                         goto out;
1203                 }
1204
1205                 buf = (char *)midQ[i]->resp_buf;
1206                 resp_iov[i].iov_base = buf;
1207                 resp_iov[i].iov_len = midQ[i]->resp_buf_size +
1208                         server->vals->header_preamble_size;
1209
1210                 if (midQ[i]->large_buf)
1211                         resp_buf_type[i] = CIFS_LARGE_BUFFER;
1212                 else
1213                         resp_buf_type[i] = CIFS_SMALL_BUFFER;
1214
1215                 rc = server->ops->check_receive(midQ[i], server,
1216                                                      flags & CIFS_LOG_ERROR);
1217
1218                 /* mark it so buf will not be freed by cifs_delete_mid */
1219                 if ((flags & CIFS_NO_RSP_BUF) == 0)
1220                         midQ[i]->resp_buf = NULL;
1221
1222         }
1223
1224         /*
1225          * Compounding is never used during session establish.
1226          */
1227         if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP)) {
1228                 struct kvec iov = {
1229                         .iov_base = resp_iov[0].iov_base,
1230                         .iov_len = resp_iov[0].iov_len
1231                 };
1232                 smb311_update_preauth_hash(ses, &iov, 1);
1233         }
1234
1235 out:
1236         /*
1237          * This will dequeue all mids. After this it is important that the
1238          * demultiplex_thread will not process any of these mids any futher.
1239          * This is prevented above by using a noop callback that will not
1240          * wake this thread except for the very last PDU.
1241          */
1242         for (i = 0; i < num_rqst; i++) {
1243                 if (!cancelled_mid[i])
1244                         cifs_delete_mid(midQ[i]);
1245         }
1246
1247         return rc;
1248 }
1249
1250 int
1251 cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
1252                struct TCP_Server_Info *server,
1253                struct smb_rqst *rqst, int *resp_buf_type, const int flags,
1254                struct kvec *resp_iov)
1255 {
1256         return compound_send_recv(xid, ses, server, flags, 1,
1257                                   rqst, resp_buf_type, resp_iov);
1258 }
1259
1260 int
1261 SendReceive2(const unsigned int xid, struct cifs_ses *ses,
1262              struct kvec *iov, int n_vec, int *resp_buf_type /* ret */,
1263              const int flags, struct kvec *resp_iov)
1264 {
1265         struct smb_rqst rqst;
1266         struct kvec s_iov[CIFS_MAX_IOV_SIZE], *new_iov;
1267         int rc;
1268
1269         if (n_vec + 1 > CIFS_MAX_IOV_SIZE) {
1270                 new_iov = kmalloc_array(n_vec + 1, sizeof(struct kvec),
1271                                         GFP_KERNEL);
1272                 if (!new_iov) {
1273                         /* otherwise cifs_send_recv below sets resp_buf_type */
1274                         *resp_buf_type = CIFS_NO_BUFFER;
1275                         return -ENOMEM;
1276                 }
1277         } else
1278                 new_iov = s_iov;
1279
1280         /* 1st iov is a RFC1001 length followed by the rest of the packet */
1281         memcpy(new_iov + 1, iov, (sizeof(struct kvec) * n_vec));
1282
1283         new_iov[0].iov_base = new_iov[1].iov_base;
1284         new_iov[0].iov_len = 4;
1285         new_iov[1].iov_base += 4;
1286         new_iov[1].iov_len -= 4;
1287
1288         memset(&rqst, 0, sizeof(struct smb_rqst));
1289         rqst.rq_iov = new_iov;
1290         rqst.rq_nvec = n_vec + 1;
1291
1292         rc = cifs_send_recv(xid, ses, ses->server,
1293                             &rqst, resp_buf_type, flags, resp_iov);
1294         if (n_vec + 1 > CIFS_MAX_IOV_SIZE)
1295                 kfree(new_iov);
1296         return rc;
1297 }
1298
1299 int
1300 SendReceive(const unsigned int xid, struct cifs_ses *ses,
1301             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
1302             int *pbytes_returned, const int flags)
1303 {
1304         int rc = 0;
1305         struct mid_q_entry *midQ;
1306         unsigned int len = be32_to_cpu(in_buf->smb_buf_length);
1307         struct kvec iov = { .iov_base = in_buf, .iov_len = len };
1308         struct smb_rqst rqst = { .rq_iov = &iov, .rq_nvec = 1 };
1309         struct cifs_credits credits = { .value = 1, .instance = 0 };
1310         struct TCP_Server_Info *server;
1311
1312         if (ses == NULL) {
1313                 cifs_dbg(VFS, "Null smb session\n");
1314                 return -EIO;
1315         }
1316         server = ses->server;
1317         if (server == NULL) {
1318                 cifs_dbg(VFS, "Null tcp session\n");
1319                 return -EIO;
1320         }
1321
1322         if (server->tcpStatus == CifsExiting)
1323                 return -ENOENT;
1324
1325         /* Ensure that we do not send more than 50 overlapping requests
1326            to the same server. We may make this configurable later or
1327            use ses->maxReq */
1328
1329         if (len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
1330                 cifs_server_dbg(VFS, "Invalid length, greater than maximum frame, %d\n",
1331                                 len);
1332                 return -EIO;
1333         }
1334
1335         rc = wait_for_free_request(server, flags, &credits.instance);
1336         if (rc)
1337                 return rc;
1338
1339         /* make sure that we sign in the same order that we send on this socket
1340            and avoid races inside tcp sendmsg code that could cause corruption
1341            of smb data */
1342
1343         mutex_lock(&server->srv_mutex);
1344
1345         rc = allocate_mid(ses, in_buf, &midQ);
1346         if (rc) {
1347                 mutex_unlock(&server->srv_mutex);
1348                 /* Update # of requests on wire to server */
1349                 add_credits(server, &credits, 0);
1350                 return rc;
1351         }
1352
1353         rc = cifs_sign_smb(in_buf, server, &midQ->sequence_number);
1354         if (rc) {
1355                 mutex_unlock(&server->srv_mutex);
1356                 goto out;
1357         }
1358
1359         midQ->mid_state = MID_REQUEST_SUBMITTED;
1360
1361         cifs_in_send_inc(server);
1362         rc = smb_send(server, in_buf, len);
1363         cifs_in_send_dec(server);
1364         cifs_save_when_sent(midQ);
1365
1366         if (rc < 0)
1367                 server->sequence_number -= 2;
1368
1369         mutex_unlock(&server->srv_mutex);
1370
1371         if (rc < 0)
1372                 goto out;
1373
1374         rc = wait_for_response(server, midQ);
1375         if (rc != 0) {
1376                 send_cancel(server, &rqst, midQ);
1377                 spin_lock(&GlobalMid_Lock);
1378                 if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
1379                         /* no longer considered to be "in-flight" */
1380                         midQ->callback = DeleteMidQEntry;
1381                         spin_unlock(&GlobalMid_Lock);
1382                         add_credits(server, &credits, 0);
1383                         return rc;
1384                 }
1385                 spin_unlock(&GlobalMid_Lock);
1386         }
1387
1388         rc = cifs_sync_mid_result(midQ, server);
1389         if (rc != 0) {
1390                 add_credits(server, &credits, 0);
1391                 return rc;
1392         }
1393
1394         if (!midQ->resp_buf || !out_buf ||
1395             midQ->mid_state != MID_RESPONSE_RECEIVED) {
1396                 rc = -EIO;
1397                 cifs_server_dbg(VFS, "Bad MID state?\n");
1398                 goto out;
1399         }
1400
1401         *pbytes_returned = get_rfc1002_length(midQ->resp_buf);
1402         memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
1403         rc = cifs_check_receive(midQ, server, 0);
1404 out:
1405         cifs_delete_mid(midQ);
1406         add_credits(server, &credits, 0);
1407
1408         return rc;
1409 }
1410
1411 /* We send a LOCKINGX_CANCEL_LOCK to cause the Windows
1412    blocking lock to return. */
1413
1414 static int
1415 send_lock_cancel(const unsigned int xid, struct cifs_tcon *tcon,
1416                         struct smb_hdr *in_buf,
1417                         struct smb_hdr *out_buf)
1418 {
1419         int bytes_returned;
1420         struct cifs_ses *ses = tcon->ses;
1421         LOCK_REQ *pSMB = (LOCK_REQ *)in_buf;
1422
1423         /* We just modify the current in_buf to change
1424            the type of lock from LOCKING_ANDX_SHARED_LOCK
1425            or LOCKING_ANDX_EXCLUSIVE_LOCK to
1426            LOCKING_ANDX_CANCEL_LOCK. */
1427
1428         pSMB->LockType = LOCKING_ANDX_CANCEL_LOCK|LOCKING_ANDX_LARGE_FILES;
1429         pSMB->Timeout = 0;
1430         pSMB->hdr.Mid = get_next_mid(ses->server);
1431
1432         return SendReceive(xid, ses, in_buf, out_buf,
1433                         &bytes_returned, 0);
1434 }
1435
1436 int
1437 SendReceiveBlockingLock(const unsigned int xid, struct cifs_tcon *tcon,
1438             struct smb_hdr *in_buf, struct smb_hdr *out_buf,
1439             int *pbytes_returned)
1440 {
1441         int rc = 0;
1442         int rstart = 0;
1443         struct mid_q_entry *midQ;
1444         struct cifs_ses *ses;
1445         unsigned int len = be32_to_cpu(in_buf->smb_buf_length);
1446         struct kvec iov = { .iov_base = in_buf, .iov_len = len };
1447         struct smb_rqst rqst = { .rq_iov = &iov, .rq_nvec = 1 };
1448         unsigned int instance;
1449         struct TCP_Server_Info *server;
1450
1451         if (tcon == NULL || tcon->ses == NULL) {
1452                 cifs_dbg(VFS, "Null smb session\n");
1453                 return -EIO;
1454         }
1455         ses = tcon->ses;
1456         server = ses->server;
1457
1458         if (server == NULL) {
1459                 cifs_dbg(VFS, "Null tcp session\n");
1460                 return -EIO;
1461         }
1462
1463         if (server->tcpStatus == CifsExiting)
1464                 return -ENOENT;
1465
1466         /* Ensure that we do not send more than 50 overlapping requests
1467            to the same server. We may make this configurable later or
1468            use ses->maxReq */
1469
1470         if (len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
1471                 cifs_tcon_dbg(VFS, "Invalid length, greater than maximum frame, %d\n",
1472                               len);
1473                 return -EIO;
1474         }
1475
1476         rc = wait_for_free_request(server, CIFS_BLOCKING_OP, &instance);
1477         if (rc)
1478                 return rc;
1479
1480         /* make sure that we sign in the same order that we send on this socket
1481            and avoid races inside tcp sendmsg code that could cause corruption
1482            of smb data */
1483
1484         mutex_lock(&server->srv_mutex);
1485
1486         rc = allocate_mid(ses, in_buf, &midQ);
1487         if (rc) {
1488                 mutex_unlock(&server->srv_mutex);
1489                 return rc;
1490         }
1491
1492         rc = cifs_sign_smb(in_buf, server, &midQ->sequence_number);
1493         if (rc) {
1494                 cifs_delete_mid(midQ);
1495                 mutex_unlock(&server->srv_mutex);
1496                 return rc;
1497         }
1498
1499         midQ->mid_state = MID_REQUEST_SUBMITTED;
1500         cifs_in_send_inc(server);
1501         rc = smb_send(server, in_buf, len);
1502         cifs_in_send_dec(server);
1503         cifs_save_when_sent(midQ);
1504
1505         if (rc < 0)
1506                 server->sequence_number -= 2;
1507
1508         mutex_unlock(&server->srv_mutex);
1509
1510         if (rc < 0) {
1511                 cifs_delete_mid(midQ);
1512                 return rc;
1513         }
1514
1515         /* Wait for a reply - allow signals to interrupt. */
1516         rc = wait_event_interruptible(server->response_q,
1517                 (!(midQ->mid_state == MID_REQUEST_SUBMITTED)) ||
1518                 ((server->tcpStatus != CifsGood) &&
1519                  (server->tcpStatus != CifsNew)));
1520
1521         /* Were we interrupted by a signal ? */
1522         if ((rc == -ERESTARTSYS) &&
1523                 (midQ->mid_state == MID_REQUEST_SUBMITTED) &&
1524                 ((server->tcpStatus == CifsGood) ||
1525                  (server->tcpStatus == CifsNew))) {
1526
1527                 if (in_buf->Command == SMB_COM_TRANSACTION2) {
1528                         /* POSIX lock. We send a NT_CANCEL SMB to cause the
1529                            blocking lock to return. */
1530                         rc = send_cancel(server, &rqst, midQ);
1531                         if (rc) {
1532                                 cifs_delete_mid(midQ);
1533                                 return rc;
1534                         }
1535                 } else {
1536                         /* Windows lock. We send a LOCKINGX_CANCEL_LOCK
1537                            to cause the blocking lock to return. */
1538
1539                         rc = send_lock_cancel(xid, tcon, in_buf, out_buf);
1540
1541                         /* If we get -ENOLCK back the lock may have
1542                            already been removed. Don't exit in this case. */
1543                         if (rc && rc != -ENOLCK) {
1544                                 cifs_delete_mid(midQ);
1545                                 return rc;
1546                         }
1547                 }
1548
1549                 rc = wait_for_response(server, midQ);
1550                 if (rc) {
1551                         send_cancel(server, &rqst, midQ);
1552                         spin_lock(&GlobalMid_Lock);
1553                         if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
1554                                 /* no longer considered to be "in-flight" */
1555                                 midQ->callback = DeleteMidQEntry;
1556                                 spin_unlock(&GlobalMid_Lock);
1557                                 return rc;
1558                         }
1559                         spin_unlock(&GlobalMid_Lock);
1560                 }
1561
1562                 /* We got the response - restart system call. */
1563                 rstart = 1;
1564         }
1565
1566         rc = cifs_sync_mid_result(midQ, server);
1567         if (rc != 0)
1568                 return rc;
1569
1570         /* rcvd frame is ok */
1571         if (out_buf == NULL || midQ->mid_state != MID_RESPONSE_RECEIVED) {
1572                 rc = -EIO;
1573                 cifs_tcon_dbg(VFS, "Bad MID state?\n");
1574                 goto out;
1575         }
1576
1577         *pbytes_returned = get_rfc1002_length(midQ->resp_buf);
1578         memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
1579         rc = cifs_check_receive(midQ, server, 0);
1580 out:
1581         cifs_delete_mid(midQ);
1582         if (rstart && rc == -EACCES)
1583                 return -ERESTARTSYS;
1584         return rc;
1585 }