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1/*
2 * fs/cifs/transport.c
3 *
4 * Copyright (C) International Business Machines Corp., 2002,2008
5 * Author(s): Steve French (sfrench@us.ibm.com)
6 * Jeremy Allison (jra@samba.org) 2006.
7 *
8 * This library is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU Lesser General Public License as published
10 * by the Free Software Foundation; either version 2.1 of the License, or
11 * (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
16 * the GNU Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public License
19 * along with this library; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 */
22
23#include <linux/fs.h>
24#include <linux/list.h>
25#include <linux/gfp.h>
26#include <linux/wait.h>
27#include <linux/net.h>
28#include <linux/delay.h>
29#include <linux/freezer.h>
30#include <asm/uaccess.h>
31#include <asm/processor.h>
32#include <linux/mempool.h>
33#include "cifspdu.h"
34#include "cifsglob.h"
35#include "cifsproto.h"
36#include "cifs_debug.h"
37
38extern mempool_t *cifs_mid_poolp;
39
40static void
41wake_up_task(struct mid_q_entry *mid)
42{
43 wake_up_process(mid->callback_data);
44}
45
46struct mid_q_entry *
47AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
48{
49 struct mid_q_entry *temp;
50
51 if (server == NULL) {
52 cERROR(1, "Null TCP session in AllocMidQEntry");
53 return NULL;
54 }
55
56 temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
57 if (temp == NULL)
58 return temp;
59 else {
60 memset(temp, 0, sizeof(struct mid_q_entry));
61 temp->mid = smb_buffer->Mid; /* always LE */
62 temp->pid = current->pid;
63 temp->command = cpu_to_le16(smb_buffer->Command);
64 cFYI(1, "For smb_command %d", smb_buffer->Command);
65 /* do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */
66 /* when mid allocated can be before when sent */
67 temp->when_alloc = jiffies;
68
69 /*
70 * The default is for the mid to be synchronous, so the
71 * default callback just wakes up the current task.
72 */
73 temp->callback = wake_up_task;
74 temp->callback_data = current;
75 }
76
77 atomic_inc(&midCount);
78 temp->mid_state = MID_REQUEST_ALLOCATED;
79 return temp;
80}
81
82void
83DeleteMidQEntry(struct mid_q_entry *midEntry)
84{
85#ifdef CONFIG_CIFS_STATS2
86 unsigned long now;
87#endif
88 midEntry->mid_state = MID_FREE;
89 atomic_dec(&midCount);
90 if (midEntry->large_buf)
91 cifs_buf_release(midEntry->resp_buf);
92 else
93 cifs_small_buf_release(midEntry->resp_buf);
94#ifdef CONFIG_CIFS_STATS2
95 now = jiffies;
96 /* commands taking longer than one second are indications that
97 something is wrong, unless it is quite a slow link or server */
98 if ((now - midEntry->when_alloc) > HZ) {
99 if ((cifsFYI & CIFS_TIMER) &&
100 (midEntry->command != cpu_to_le16(SMB_COM_LOCKING_ANDX))) {
101 printk(KERN_DEBUG " CIFS slow rsp: cmd %d mid %llu",
102 midEntry->command, midEntry->mid);
103 printk(" A: 0x%lx S: 0x%lx R: 0x%lx\n",
104 now - midEntry->when_alloc,
105 now - midEntry->when_sent,
106 now - midEntry->when_received);
107 }
108 }
109#endif
110 mempool_free(midEntry, cifs_mid_poolp);
111}
112
113static void
114delete_mid(struct mid_q_entry *mid)
115{
116 spin_lock(&GlobalMid_Lock);
117 list_del(&mid->qhead);
118 spin_unlock(&GlobalMid_Lock);
119
120 DeleteMidQEntry(mid);
121}
122
123static int
124smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
125{
126 int rc = 0;
127 int i = 0;
128 struct msghdr smb_msg;
129 __be32 *buf_len = (__be32 *)(iov[0].iov_base);
130 unsigned int len = iov[0].iov_len;
131 unsigned int total_len;
132 int first_vec = 0;
133 unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);
134 struct socket *ssocket = server->ssocket;
135
136 if (ssocket == NULL)
137 return -ENOTSOCK; /* BB eventually add reconnect code here */
138
139 smb_msg.msg_name = (struct sockaddr *) &server->dstaddr;
140 smb_msg.msg_namelen = sizeof(struct sockaddr);
141 smb_msg.msg_control = NULL;
142 smb_msg.msg_controllen = 0;
143 if (server->noblocksnd)
144 smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL;
145 else
146 smb_msg.msg_flags = MSG_NOSIGNAL;
147
148 total_len = 0;
149 for (i = 0; i < n_vec; i++)
150 total_len += iov[i].iov_len;
151
152 cFYI(1, "Sending smb: total_len %d", total_len);
153 dump_smb(iov[0].iov_base, len);
154
155 i = 0;
156 while (total_len) {
157 rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
158 n_vec - first_vec, total_len);
159 if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
160 i++;
161 /*
162 * If blocking send we try 3 times, since each can block
163 * for 5 seconds. For nonblocking we have to try more
164 * but wait increasing amounts of time allowing time for
165 * socket to clear. The overall time we wait in either
166 * case to send on the socket is about 15 seconds.
167 * Similarly we wait for 15 seconds for a response from
168 * the server in SendReceive[2] for the server to send
169 * a response back for most types of requests (except
170 * SMB Write past end of file which can be slow, and
171 * blocking lock operations). NFS waits slightly longer
172 * than CIFS, but this can make it take longer for
173 * nonresponsive servers to be detected and 15 seconds
174 * is more than enough time for modern networks to
175 * send a packet. In most cases if we fail to send
176 * after the retries we will kill the socket and
177 * reconnect which may clear the network problem.
178 */
179 if ((i >= 14) || (!server->noblocksnd && (i > 2))) {
180 cERROR(1, "sends on sock %p stuck for 15 seconds",
181 ssocket);
182 rc = -EAGAIN;
183 break;
184 }
185 msleep(1 << i);
186 continue;
187 }
188 if (rc < 0)
189 break;
190
191 if (rc == total_len) {
192 total_len = 0;
193 break;
194 } else if (rc > total_len) {
195 cERROR(1, "sent %d requested %d", rc, total_len);
196 break;
197 }
198 if (rc == 0) {
199 /* should never happen, letting socket clear before
200 retrying is our only obvious option here */
201 cERROR(1, "tcp sent no data");
202 msleep(500);
203 continue;
204 }
205 total_len -= rc;
206 /* the line below resets i */
207 for (i = first_vec; i < n_vec; i++) {
208 if (iov[i].iov_len) {
209 if (rc > iov[i].iov_len) {
210 rc -= iov[i].iov_len;
211 iov[i].iov_len = 0;
212 } else {
213 iov[i].iov_base += rc;
214 iov[i].iov_len -= rc;
215 first_vec = i;
216 break;
217 }
218 }
219 }
220 i = 0; /* in case we get ENOSPC on the next send */
221 }
222
223 if ((total_len > 0) && (total_len != smb_buf_length + 4)) {
224 cFYI(1, "partial send (%d remaining), terminating session",
225 total_len);
226 /* If we have only sent part of an SMB then the next SMB
227 could be taken as the remainder of this one. We need
228 to kill the socket so the server throws away the partial
229 SMB */
230 server->tcpStatus = CifsNeedReconnect;
231 }
232
233 if (rc < 0 && rc != -EINTR)
234 cERROR(1, "Error %d sending data on socket to server", rc);
235 else
236 rc = 0;
237
238 /* Don't want to modify the buffer as a side effect of this call. */
239 *buf_len = cpu_to_be32(smb_buf_length);
240
241 return rc;
242}
243
244int
245smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
246 unsigned int smb_buf_length)
247{
248 struct kvec iov;
249
250 iov.iov_base = smb_buffer;
251 iov.iov_len = smb_buf_length + 4;
252
253 return smb_sendv(server, &iov, 1);
254}
255
256static int
257wait_for_free_credits(struct TCP_Server_Info *server, const int optype,
258 int *credits)
259{
260 int rc;
261
262 spin_lock(&server->req_lock);
263 if (optype == CIFS_ASYNC_OP) {
264 /* oplock breaks must not be held up */
265 server->in_flight++;
266 *credits -= 1;
267 spin_unlock(&server->req_lock);
268 return 0;
269 }
270
271 while (1) {
272 if (*credits <= 0) {
273 spin_unlock(&server->req_lock);
274 cifs_num_waiters_inc(server);
275 rc = wait_event_killable(server->request_q,
276 has_credits(server, credits));
277 cifs_num_waiters_dec(server);
278 if (rc)
279 return rc;
280 spin_lock(&server->req_lock);
281 } else {
282 if (server->tcpStatus == CifsExiting) {
283 spin_unlock(&server->req_lock);
284 return -ENOENT;
285 }
286
287 /*
288 * Can not count locking commands against total
289 * as they are allowed to block on server.
290 */
291
292 /* update # of requests on the wire to server */
293 if (optype != CIFS_BLOCKING_OP) {
294 *credits -= 1;
295 server->in_flight++;
296 }
297 spin_unlock(&server->req_lock);
298 break;
299 }
300 }
301 return 0;
302}
303
304static int
305wait_for_free_request(struct TCP_Server_Info *server, const int optype)
306{
307 return wait_for_free_credits(server, optype,
308 server->ops->get_credits_field(server));
309}
310
311static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,
312 struct mid_q_entry **ppmidQ)
313{
314 if (ses->server->tcpStatus == CifsExiting) {
315 return -ENOENT;
316 }
317
318 if (ses->server->tcpStatus == CifsNeedReconnect) {
319 cFYI(1, "tcp session dead - return to caller to retry");
320 return -EAGAIN;
321 }
322
323 if (ses->status != CifsGood) {
324 /* check if SMB session is bad because we are setting it up */
325 if ((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
326 (in_buf->Command != SMB_COM_NEGOTIATE))
327 return -EAGAIN;
328 /* else ok - we are setting up session */
329 }
330 *ppmidQ = AllocMidQEntry(in_buf, ses->server);
331 if (*ppmidQ == NULL)
332 return -ENOMEM;
333 spin_lock(&GlobalMid_Lock);
334 list_add_tail(&(*ppmidQ)->qhead, &ses->server->pending_mid_q);
335 spin_unlock(&GlobalMid_Lock);
336 return 0;
337}
338
339static int
340wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
341{
342 int error;
343
344 error = wait_event_freezekillable(server->response_q,
345 midQ->mid_state != MID_REQUEST_SUBMITTED);
346 if (error < 0)
347 return -ERESTARTSYS;
348
349 return 0;
350}
351
352static int
353cifs_setup_async_request(struct TCP_Server_Info *server, struct kvec *iov,
354 unsigned int nvec, struct mid_q_entry **ret_mid)
355{
356 int rc;
357 struct smb_hdr *hdr = (struct smb_hdr *)iov[0].iov_base;
358 struct mid_q_entry *mid;
359
360 /* enable signing if server requires it */
361 if (server->sec_mode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
362 hdr->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
363
364 mid = AllocMidQEntry(hdr, server);
365 if (mid == NULL)
366 return -ENOMEM;
367
368 rc = cifs_sign_smb2(iov, nvec, server, &mid->sequence_number);
369 if (rc) {
370 DeleteMidQEntry(mid);
371 return rc;
372 }
373
374 *ret_mid = mid;
375 return 0;
376}
377
378/*
379 * Send a SMB request and set the callback function in the mid to handle
380 * the result. Caller is responsible for dealing with timeouts.
381 */
382int
383cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
384 unsigned int nvec, mid_receive_t *receive,
385 mid_callback_t *callback, void *cbdata, bool ignore_pend)
386{
387 int rc;
388 struct mid_q_entry *mid;
389
390 rc = wait_for_free_request(server, ignore_pend ? CIFS_ASYNC_OP : 0);
391 if (rc)
392 return rc;
393
394 mutex_lock(&server->srv_mutex);
395 rc = cifs_setup_async_request(server, iov, nvec, &mid);
396 if (rc) {
397 mutex_unlock(&server->srv_mutex);
398 add_credits(server, 1);
399 wake_up(&server->request_q);
400 return rc;
401 }
402
403 mid->receive = receive;
404 mid->callback = callback;
405 mid->callback_data = cbdata;
406 mid->mid_state = MID_REQUEST_SUBMITTED;
407
408 /* put it on the pending_mid_q */
409 spin_lock(&GlobalMid_Lock);
410 list_add_tail(&mid->qhead, &server->pending_mid_q);
411 spin_unlock(&GlobalMid_Lock);
412
413
414 cifs_in_send_inc(server);
415 rc = smb_sendv(server, iov, nvec);
416 cifs_in_send_dec(server);
417 cifs_save_when_sent(mid);
418 mutex_unlock(&server->srv_mutex);
419
420 if (rc == 0)
421 return 0;
422
423 delete_mid(mid);
424 add_credits(server, 1);
425 wake_up(&server->request_q);
426 return rc;
427}
428
429/*
430 *
431 * Send an SMB Request. No response info (other than return code)
432 * needs to be parsed.
433 *
434 * flags indicate the type of request buffer and how long to wait
435 * and whether to log NT STATUS code (error) before mapping it to POSIX error
436 *
437 */
438int
439SendReceiveNoRsp(const unsigned int xid, struct cifs_ses *ses,
440 char *in_buf, int flags)
441{
442 int rc;
443 struct kvec iov[1];
444 int resp_buf_type;
445
446 iov[0].iov_base = in_buf;
447 iov[0].iov_len = get_rfc1002_length(in_buf) + 4;
448 flags |= CIFS_NO_RESP;
449 rc = SendReceive2(xid, ses, iov, 1, &resp_buf_type, flags);
450 cFYI(DBG2, "SendRcvNoRsp flags %d rc %d", flags, rc);
451
452 return rc;
453}
454
455static int
456cifs_sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
457{
458 int rc = 0;
459
460 cFYI(1, "%s: cmd=%d mid=%llu state=%d", __func__,
461 le16_to_cpu(mid->command), mid->mid, mid->mid_state);
462
463 spin_lock(&GlobalMid_Lock);
464 switch (mid->mid_state) {
465 case MID_RESPONSE_RECEIVED:
466 spin_unlock(&GlobalMid_Lock);
467 return rc;
468 case MID_RETRY_NEEDED:
469 rc = -EAGAIN;
470 break;
471 case MID_RESPONSE_MALFORMED:
472 rc = -EIO;
473 break;
474 case MID_SHUTDOWN:
475 rc = -EHOSTDOWN;
476 break;
477 default:
478 list_del_init(&mid->qhead);
479 cERROR(1, "%s: invalid mid state mid=%llu state=%d", __func__,
480 mid->mid, mid->mid_state);
481 rc = -EIO;
482 }
483 spin_unlock(&GlobalMid_Lock);
484
485 DeleteMidQEntry(mid);
486 return rc;
487}
488
489static inline int
490send_cancel(struct TCP_Server_Info *server, void *buf, struct mid_q_entry *mid)
491{
492 return server->ops->send_cancel ?
493 server->ops->send_cancel(server, buf, mid) : 0;
494}
495
496int
497cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
498 bool log_error)
499{
500 unsigned int len = get_rfc1002_length(mid->resp_buf) + 4;
501
502 dump_smb(mid->resp_buf, min_t(u32, 92, len));
503
504 /* convert the length into a more usable form */
505 if (server->sec_mode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
506 struct kvec iov;
507
508 iov.iov_base = mid->resp_buf;
509 iov.iov_len = len;
510 /* FIXME: add code to kill session */
511 if (cifs_verify_signature(&iov, 1, server,
512 mid->sequence_number + 1) != 0)
513 cERROR(1, "Unexpected SMB signature");
514 }
515
516 /* BB special case reconnect tid and uid here? */
517 return map_smb_to_linux_error(mid->resp_buf, log_error);
518}
519
520int
521cifs_setup_request(struct cifs_ses *ses, struct kvec *iov,
522 unsigned int nvec, struct mid_q_entry **ret_mid)
523{
524 int rc;
525 struct smb_hdr *hdr = (struct smb_hdr *)iov[0].iov_base;
526 struct mid_q_entry *mid;
527
528 rc = allocate_mid(ses, hdr, &mid);
529 if (rc)
530 return rc;
531 rc = cifs_sign_smb2(iov, nvec, ses->server, &mid->sequence_number);
532 if (rc)
533 delete_mid(mid);
534 *ret_mid = mid;
535 return rc;
536}
537
538int
539SendReceive2(const unsigned int xid, struct cifs_ses *ses,
540 struct kvec *iov, int n_vec, int *pRespBufType /* ret */,
541 const int flags)
542{
543 int rc = 0;
544 int long_op;
545 struct mid_q_entry *midQ;
546 char *buf = iov[0].iov_base;
547
548 long_op = flags & CIFS_TIMEOUT_MASK;
549
550 *pRespBufType = CIFS_NO_BUFFER; /* no response buf yet */
551
552 if ((ses == NULL) || (ses->server == NULL)) {
553 cifs_small_buf_release(buf);
554 cERROR(1, "Null session");
555 return -EIO;
556 }
557
558 if (ses->server->tcpStatus == CifsExiting) {
559 cifs_small_buf_release(buf);
560 return -ENOENT;
561 }
562
563 /*
564 * Ensure that we do not send more than 50 overlapping requests
565 * to the same server. We may make this configurable later or
566 * use ses->maxReq.
567 */
568
569 rc = wait_for_free_request(ses->server, long_op);
570 if (rc) {
571 cifs_small_buf_release(buf);
572 return rc;
573 }
574
575 /*
576 * Make sure that we sign in the same order that we send on this socket
577 * and avoid races inside tcp sendmsg code that could cause corruption
578 * of smb data.
579 */
580
581 mutex_lock(&ses->server->srv_mutex);
582
583 rc = ses->server->ops->setup_request(ses, iov, n_vec, &midQ);
584 if (rc) {
585 mutex_unlock(&ses->server->srv_mutex);
586 cifs_small_buf_release(buf);
587 /* Update # of requests on wire to server */
588 add_credits(ses->server, 1);
589 return rc;
590 }
591
592 midQ->mid_state = MID_REQUEST_SUBMITTED;
593 cifs_in_send_inc(ses->server);
594 rc = smb_sendv(ses->server, iov, n_vec);
595 cifs_in_send_dec(ses->server);
596 cifs_save_when_sent(midQ);
597
598 mutex_unlock(&ses->server->srv_mutex);
599
600 if (rc < 0) {
601 cifs_small_buf_release(buf);
602 goto out;
603 }
604
605 if (long_op == CIFS_ASYNC_OP) {
606 cifs_small_buf_release(buf);
607 goto out;
608 }
609
610 rc = wait_for_response(ses->server, midQ);
611 if (rc != 0) {
612 send_cancel(ses->server, buf, midQ);
613 spin_lock(&GlobalMid_Lock);
614 if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
615 midQ->callback = DeleteMidQEntry;
616 spin_unlock(&GlobalMid_Lock);
617 cifs_small_buf_release(buf);
618 add_credits(ses->server, 1);
619 return rc;
620 }
621 spin_unlock(&GlobalMid_Lock);
622 }
623
624 cifs_small_buf_release(buf);
625
626 rc = cifs_sync_mid_result(midQ, ses->server);
627 if (rc != 0) {
628 add_credits(ses->server, 1);
629 return rc;
630 }
631
632 if (!midQ->resp_buf || midQ->mid_state != MID_RESPONSE_RECEIVED) {
633 rc = -EIO;
634 cFYI(1, "Bad MID state?");
635 goto out;
636 }
637
638 buf = (char *)midQ->resp_buf;
639 iov[0].iov_base = buf;
640 iov[0].iov_len = get_rfc1002_length(buf) + 4;
641 if (midQ->large_buf)
642 *pRespBufType = CIFS_LARGE_BUFFER;
643 else
644 *pRespBufType = CIFS_SMALL_BUFFER;
645
646 rc = ses->server->ops->check_receive(midQ, ses->server,
647 flags & CIFS_LOG_ERROR);
648
649 /* mark it so buf will not be freed by delete_mid */
650 if ((flags & CIFS_NO_RESP) == 0)
651 midQ->resp_buf = NULL;
652out:
653 delete_mid(midQ);
654 add_credits(ses->server, 1);
655
656 return rc;
657}
658
659int
660SendReceive(const unsigned int xid, struct cifs_ses *ses,
661 struct smb_hdr *in_buf, struct smb_hdr *out_buf,
662 int *pbytes_returned, const int long_op)
663{
664 int rc = 0;
665 struct mid_q_entry *midQ;
666
667 if (ses == NULL) {
668 cERROR(1, "Null smb session");
669 return -EIO;
670 }
671 if (ses->server == NULL) {
672 cERROR(1, "Null tcp session");
673 return -EIO;
674 }
675
676 if (ses->server->tcpStatus == CifsExiting)
677 return -ENOENT;
678
679 /* Ensure that we do not send more than 50 overlapping requests
680 to the same server. We may make this configurable later or
681 use ses->maxReq */
682
683 if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
684 MAX_CIFS_HDR_SIZE - 4) {
685 cERROR(1, "Illegal length, greater than maximum frame, %d",
686 be32_to_cpu(in_buf->smb_buf_length));
687 return -EIO;
688 }
689
690 rc = wait_for_free_request(ses->server, long_op);
691 if (rc)
692 return rc;
693
694 /* make sure that we sign in the same order that we send on this socket
695 and avoid races inside tcp sendmsg code that could cause corruption
696 of smb data */
697
698 mutex_lock(&ses->server->srv_mutex);
699
700 rc = allocate_mid(ses, in_buf, &midQ);
701 if (rc) {
702 mutex_unlock(&ses->server->srv_mutex);
703 /* Update # of requests on wire to server */
704 add_credits(ses->server, 1);
705 return rc;
706 }
707
708 rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
709 if (rc) {
710 mutex_unlock(&ses->server->srv_mutex);
711 goto out;
712 }
713
714 midQ->mid_state = MID_REQUEST_SUBMITTED;
715
716 cifs_in_send_inc(ses->server);
717 rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
718 cifs_in_send_dec(ses->server);
719 cifs_save_when_sent(midQ);
720 mutex_unlock(&ses->server->srv_mutex);
721
722 if (rc < 0)
723 goto out;
724
725 if (long_op == CIFS_ASYNC_OP)
726 goto out;
727
728 rc = wait_for_response(ses->server, midQ);
729 if (rc != 0) {
730 send_cancel(ses->server, in_buf, midQ);
731 spin_lock(&GlobalMid_Lock);
732 if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
733 /* no longer considered to be "in-flight" */
734 midQ->callback = DeleteMidQEntry;
735 spin_unlock(&GlobalMid_Lock);
736 add_credits(ses->server, 1);
737 return rc;
738 }
739 spin_unlock(&GlobalMid_Lock);
740 }
741
742 rc = cifs_sync_mid_result(midQ, ses->server);
743 if (rc != 0) {
744 add_credits(ses->server, 1);
745 return rc;
746 }
747
748 if (!midQ->resp_buf || !out_buf ||
749 midQ->mid_state != MID_RESPONSE_RECEIVED) {
750 rc = -EIO;
751 cERROR(1, "Bad MID state?");
752 goto out;
753 }
754
755 *pbytes_returned = get_rfc1002_length(midQ->resp_buf);
756 memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
757 rc = cifs_check_receive(midQ, ses->server, 0);
758out:
759 delete_mid(midQ);
760 add_credits(ses->server, 1);
761
762 return rc;
763}
764
765/* We send a LOCKINGX_CANCEL_LOCK to cause the Windows
766 blocking lock to return. */
767
768static int
769send_lock_cancel(const unsigned int xid, struct cifs_tcon *tcon,
770 struct smb_hdr *in_buf,
771 struct smb_hdr *out_buf)
772{
773 int bytes_returned;
774 struct cifs_ses *ses = tcon->ses;
775 LOCK_REQ *pSMB = (LOCK_REQ *)in_buf;
776
777 /* We just modify the current in_buf to change
778 the type of lock from LOCKING_ANDX_SHARED_LOCK
779 or LOCKING_ANDX_EXCLUSIVE_LOCK to
780 LOCKING_ANDX_CANCEL_LOCK. */
781
782 pSMB->LockType = LOCKING_ANDX_CANCEL_LOCK|LOCKING_ANDX_LARGE_FILES;
783 pSMB->Timeout = 0;
784 pSMB->hdr.Mid = get_next_mid(ses->server);
785
786 return SendReceive(xid, ses, in_buf, out_buf,
787 &bytes_returned, 0);
788}
789
790int
791SendReceiveBlockingLock(const unsigned int xid, struct cifs_tcon *tcon,
792 struct smb_hdr *in_buf, struct smb_hdr *out_buf,
793 int *pbytes_returned)
794{
795 int rc = 0;
796 int rstart = 0;
797 struct mid_q_entry *midQ;
798 struct cifs_ses *ses;
799
800 if (tcon == NULL || tcon->ses == NULL) {
801 cERROR(1, "Null smb session");
802 return -EIO;
803 }
804 ses = tcon->ses;
805
806 if (ses->server == NULL) {
807 cERROR(1, "Null tcp session");
808 return -EIO;
809 }
810
811 if (ses->server->tcpStatus == CifsExiting)
812 return -ENOENT;
813
814 /* Ensure that we do not send more than 50 overlapping requests
815 to the same server. We may make this configurable later or
816 use ses->maxReq */
817
818 if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
819 MAX_CIFS_HDR_SIZE - 4) {
820 cERROR(1, "Illegal length, greater than maximum frame, %d",
821 be32_to_cpu(in_buf->smb_buf_length));
822 return -EIO;
823 }
824
825 rc = wait_for_free_request(ses->server, CIFS_BLOCKING_OP);
826 if (rc)
827 return rc;
828
829 /* make sure that we sign in the same order that we send on this socket
830 and avoid races inside tcp sendmsg code that could cause corruption
831 of smb data */
832
833 mutex_lock(&ses->server->srv_mutex);
834
835 rc = allocate_mid(ses, in_buf, &midQ);
836 if (rc) {
837 mutex_unlock(&ses->server->srv_mutex);
838 return rc;
839 }
840
841 rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
842 if (rc) {
843 delete_mid(midQ);
844 mutex_unlock(&ses->server->srv_mutex);
845 return rc;
846 }
847
848 midQ->mid_state = MID_REQUEST_SUBMITTED;
849 cifs_in_send_inc(ses->server);
850 rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
851 cifs_in_send_dec(ses->server);
852 cifs_save_when_sent(midQ);
853 mutex_unlock(&ses->server->srv_mutex);
854
855 if (rc < 0) {
856 delete_mid(midQ);
857 return rc;
858 }
859
860 /* Wait for a reply - allow signals to interrupt. */
861 rc = wait_event_interruptible(ses->server->response_q,
862 (!(midQ->mid_state == MID_REQUEST_SUBMITTED)) ||
863 ((ses->server->tcpStatus != CifsGood) &&
864 (ses->server->tcpStatus != CifsNew)));
865
866 /* Were we interrupted by a signal ? */
867 if ((rc == -ERESTARTSYS) &&
868 (midQ->mid_state == MID_REQUEST_SUBMITTED) &&
869 ((ses->server->tcpStatus == CifsGood) ||
870 (ses->server->tcpStatus == CifsNew))) {
871
872 if (in_buf->Command == SMB_COM_TRANSACTION2) {
873 /* POSIX lock. We send a NT_CANCEL SMB to cause the
874 blocking lock to return. */
875 rc = send_cancel(ses->server, in_buf, midQ);
876 if (rc) {
877 delete_mid(midQ);
878 return rc;
879 }
880 } else {
881 /* Windows lock. We send a LOCKINGX_CANCEL_LOCK
882 to cause the blocking lock to return. */
883
884 rc = send_lock_cancel(xid, tcon, in_buf, out_buf);
885
886 /* If we get -ENOLCK back the lock may have
887 already been removed. Don't exit in this case. */
888 if (rc && rc != -ENOLCK) {
889 delete_mid(midQ);
890 return rc;
891 }
892 }
893
894 rc = wait_for_response(ses->server, midQ);
895 if (rc) {
896 send_cancel(ses->server, in_buf, midQ);
897 spin_lock(&GlobalMid_Lock);
898 if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
899 /* no longer considered to be "in-flight" */
900 midQ->callback = DeleteMidQEntry;
901 spin_unlock(&GlobalMid_Lock);
902 return rc;
903 }
904 spin_unlock(&GlobalMid_Lock);
905 }
906
907 /* We got the response - restart system call. */
908 rstart = 1;
909 }
910
911 rc = cifs_sync_mid_result(midQ, ses->server);
912 if (rc != 0)
913 return rc;
914
915 /* rcvd frame is ok */
916 if (out_buf == NULL || midQ->mid_state != MID_RESPONSE_RECEIVED) {
917 rc = -EIO;
918 cERROR(1, "Bad MID state?");
919 goto out;
920 }
921
922 *pbytes_returned = get_rfc1002_length(midQ->resp_buf);
923 memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
924 rc = cifs_check_receive(midQ, ses->server, 0);
925out:
926 delete_mid(midQ);
927 if (rstart && rc == -EACCES)
928 return -ERESTARTSYS;
929 return rc;
930}