1 /*
2 * fs/cifs/misc.c
3 *
4 * Copyright (C) International Business Machines Corp., 2002,2008
5 * Author(s): Steve French (sfrench@us.ibm.com)
6 *
7 * This library is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU Lesser General Public License as published
9 * by the Free Software Foundation; either version 2.1 of the License, or
10 * (at your option) any later version.
11 *
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
15 * the GNU Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public License
18 * along with this library; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22 #include <linux/slab.h>
23 #include <linux/ctype.h>
24 #include <linux/mempool.h>
25 #include <linux/vmalloc.h>
26 #include "cifspdu.h"
27 #include "cifsglob.h"
28 #include "cifsproto.h"
29 #include "cifs_debug.h"
30 #include "smberr.h"
31 #include "nterr.h"
32 #include "cifs_unicode.h"
33 #include "smb2pdu.h"
34 #include "cifsfs.h"
35 #ifdef CONFIG_CIFS_DFS_UPCALL
36 #include "dns_resolve.h"
37 #endif
38 #include "fs_context.h"
39
40 extern mempool_t *cifs_sm_req_poolp;
41 extern mempool_t *cifs_req_poolp;
42
43 /* The xid serves as a useful identifier for each incoming vfs request,
44 in a similar way to the mid which is useful to track each sent smb,
45 and CurrentXid can also provide a running counter (although it
46 will eventually wrap past zero) of the total vfs operations handled
47 since the cifs fs was mounted */
48
49 unsigned int
_get_xid(void)50 _get_xid(void)
51 {
52 unsigned int xid;
53
54 spin_lock(&GlobalMid_Lock);
55 GlobalTotalActiveXid++;
56
57 /* keep high water mark for number of simultaneous ops in filesystem */
58 if (GlobalTotalActiveXid > GlobalMaxActiveXid)
59 GlobalMaxActiveXid = GlobalTotalActiveXid;
60 if (GlobalTotalActiveXid > 65000)
61 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
62 xid = GlobalCurrentXid++;
63 spin_unlock(&GlobalMid_Lock);
64 return xid;
65 }
66
67 void
_free_xid(unsigned int xid)68 _free_xid(unsigned int xid)
69 {
70 spin_lock(&GlobalMid_Lock);
71 /* if (GlobalTotalActiveXid == 0)
72 BUG(); */
73 GlobalTotalActiveXid--;
74 spin_unlock(&GlobalMid_Lock);
75 }
76
77 struct cifs_ses *
sesInfoAlloc(void)78 sesInfoAlloc(void)
79 {
80 struct cifs_ses *ret_buf;
81
82 ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
83 if (ret_buf) {
84 atomic_inc(&sesInfoAllocCount);
85 ret_buf->status = CifsNew;
86 ++ret_buf->ses_count;
87 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
88 INIT_LIST_HEAD(&ret_buf->tcon_list);
89 mutex_init(&ret_buf->session_mutex);
90 spin_lock_init(&ret_buf->iface_lock);
91 }
92 return ret_buf;
93 }
94
95 void
sesInfoFree(struct cifs_ses * buf_to_free)96 sesInfoFree(struct cifs_ses *buf_to_free)
97 {
98 if (buf_to_free == NULL) {
99 cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
100 return;
101 }
102
103 atomic_dec(&sesInfoAllocCount);
104 kfree(buf_to_free->serverOS);
105 kfree(buf_to_free->serverDomain);
106 kfree(buf_to_free->serverNOS);
107 kfree_sensitive(buf_to_free->password);
108 kfree(buf_to_free->user_name);
109 kfree(buf_to_free->domainName);
110 kfree_sensitive(buf_to_free->auth_key.response);
111 kfree(buf_to_free->iface_list);
112 kfree_sensitive(buf_to_free);
113 }
114
115 struct cifs_tcon *
tconInfoAlloc(void)116 tconInfoAlloc(void)
117 {
118 struct cifs_tcon *ret_buf;
119
120 ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
121 if (!ret_buf)
122 return NULL;
123 ret_buf->crfid.fid = kzalloc(sizeof(*ret_buf->crfid.fid), GFP_KERNEL);
124 if (!ret_buf->crfid.fid) {
125 kfree(ret_buf);
126 return NULL;
127 }
128
129 atomic_inc(&tconInfoAllocCount);
130 ret_buf->tidStatus = CifsNew;
131 ++ret_buf->tc_count;
132 INIT_LIST_HEAD(&ret_buf->openFileList);
133 INIT_LIST_HEAD(&ret_buf->tcon_list);
134 spin_lock_init(&ret_buf->open_file_lock);
135 mutex_init(&ret_buf->crfid.fid_mutex);
136 spin_lock_init(&ret_buf->stat_lock);
137 atomic_set(&ret_buf->num_local_opens, 0);
138 atomic_set(&ret_buf->num_remote_opens, 0);
139
140 return ret_buf;
141 }
142
143 void
tconInfoFree(struct cifs_tcon * buf_to_free)144 tconInfoFree(struct cifs_tcon *buf_to_free)
145 {
146 if (buf_to_free == NULL) {
147 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
148 return;
149 }
150 atomic_dec(&tconInfoAllocCount);
151 kfree(buf_to_free->nativeFileSystem);
152 kfree_sensitive(buf_to_free->password);
153 kfree(buf_to_free->crfid.fid);
154 #ifdef CONFIG_CIFS_DFS_UPCALL
155 kfree(buf_to_free->dfs_path);
156 #endif
157 kfree(buf_to_free);
158 }
159
160 struct smb_hdr *
cifs_buf_get(void)161 cifs_buf_get(void)
162 {
163 struct smb_hdr *ret_buf = NULL;
164 /*
165 * SMB2 header is bigger than CIFS one - no problems to clean some
166 * more bytes for CIFS.
167 */
168 size_t buf_size = sizeof(struct smb2_sync_hdr);
169
170 /*
171 * We could use negotiated size instead of max_msgsize -
172 * but it may be more efficient to always alloc same size
173 * albeit slightly larger than necessary and maxbuffersize
174 * defaults to this and can not be bigger.
175 */
176 ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
177
178 /* clear the first few header bytes */
179 /* for most paths, more is cleared in header_assemble */
180 memset(ret_buf, 0, buf_size + 3);
181 atomic_inc(&bufAllocCount);
182 #ifdef CONFIG_CIFS_STATS2
183 atomic_inc(&totBufAllocCount);
184 #endif /* CONFIG_CIFS_STATS2 */
185
186 return ret_buf;
187 }
188
189 void
cifs_buf_release(void * buf_to_free)190 cifs_buf_release(void *buf_to_free)
191 {
192 if (buf_to_free == NULL) {
193 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
194 return;
195 }
196 mempool_free(buf_to_free, cifs_req_poolp);
197
198 atomic_dec(&bufAllocCount);
199 return;
200 }
201
202 struct smb_hdr *
cifs_small_buf_get(void)203 cifs_small_buf_get(void)
204 {
205 struct smb_hdr *ret_buf = NULL;
206
207 /* We could use negotiated size instead of max_msgsize -
208 but it may be more efficient to always alloc same size
209 albeit slightly larger than necessary and maxbuffersize
210 defaults to this and can not be bigger */
211 ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
212 /* No need to clear memory here, cleared in header assemble */
213 /* memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
214 atomic_inc(&smBufAllocCount);
215 #ifdef CONFIG_CIFS_STATS2
216 atomic_inc(&totSmBufAllocCount);
217 #endif /* CONFIG_CIFS_STATS2 */
218
219 return ret_buf;
220 }
221
222 void
cifs_small_buf_release(void * buf_to_free)223 cifs_small_buf_release(void *buf_to_free)
224 {
225
226 if (buf_to_free == NULL) {
227 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
228 return;
229 }
230 mempool_free(buf_to_free, cifs_sm_req_poolp);
231
232 atomic_dec(&smBufAllocCount);
233 return;
234 }
235
236 void
free_rsp_buf(int resp_buftype,void * rsp)237 free_rsp_buf(int resp_buftype, void *rsp)
238 {
239 if (resp_buftype == CIFS_SMALL_BUFFER)
240 cifs_small_buf_release(rsp);
241 else if (resp_buftype == CIFS_LARGE_BUFFER)
242 cifs_buf_release(rsp);
243 }
244
245 /* NB: MID can not be set if treeCon not passed in, in that
246 case it is responsbility of caller to set the mid */
247 void
header_assemble(struct smb_hdr * buffer,char smb_command,const struct cifs_tcon * treeCon,int word_count)248 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
249 const struct cifs_tcon *treeCon, int word_count
250 /* length of fixed section (word count) in two byte units */)
251 {
252 char *temp = (char *) buffer;
253
254 memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
255
256 buffer->smb_buf_length = cpu_to_be32(
257 (2 * word_count) + sizeof(struct smb_hdr) -
258 4 /* RFC 1001 length field does not count */ +
259 2 /* for bcc field itself */) ;
260
261 buffer->Protocol[0] = 0xFF;
262 buffer->Protocol[1] = 'S';
263 buffer->Protocol[2] = 'M';
264 buffer->Protocol[3] = 'B';
265 buffer->Command = smb_command;
266 buffer->Flags = 0x00; /* case sensitive */
267 buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
268 buffer->Pid = cpu_to_le16((__u16)current->tgid);
269 buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
270 if (treeCon) {
271 buffer->Tid = treeCon->tid;
272 if (treeCon->ses) {
273 if (treeCon->ses->capabilities & CAP_UNICODE)
274 buffer->Flags2 |= SMBFLG2_UNICODE;
275 if (treeCon->ses->capabilities & CAP_STATUS32)
276 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
277
278 /* Uid is not converted */
279 buffer->Uid = treeCon->ses->Suid;
280 buffer->Mid = get_next_mid(treeCon->ses->server);
281 }
282 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
283 buffer->Flags2 |= SMBFLG2_DFS;
284 if (treeCon->nocase)
285 buffer->Flags |= SMBFLG_CASELESS;
286 if ((treeCon->ses) && (treeCon->ses->server))
287 if (treeCon->ses->server->sign)
288 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
289 }
290
291 /* endian conversion of flags is now done just before sending */
292 buffer->WordCount = (char) word_count;
293 return;
294 }
295
296 static int
check_smb_hdr(struct smb_hdr * smb)297 check_smb_hdr(struct smb_hdr *smb)
298 {
299 /* does it have the right SMB "signature" ? */
300 if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
301 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
302 *(unsigned int *)smb->Protocol);
303 return 1;
304 }
305
306 /* if it's a response then accept */
307 if (smb->Flags & SMBFLG_RESPONSE)
308 return 0;
309
310 /* only one valid case where server sends us request */
311 if (smb->Command == SMB_COM_LOCKING_ANDX)
312 return 0;
313
314 cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
315 get_mid(smb));
316 return 1;
317 }
318
319 int
checkSMB(char * buf,unsigned int total_read,struct TCP_Server_Info * server)320 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
321 {
322 struct smb_hdr *smb = (struct smb_hdr *)buf;
323 __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
324 __u32 clc_len; /* calculated length */
325 cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
326 total_read, rfclen);
327
328 /* is this frame too small to even get to a BCC? */
329 if (total_read < 2 + sizeof(struct smb_hdr)) {
330 if ((total_read >= sizeof(struct smb_hdr) - 1)
331 && (smb->Status.CifsError != 0)) {
332 /* it's an error return */
333 smb->WordCount = 0;
334 /* some error cases do not return wct and bcc */
335 return 0;
336 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
337 (smb->WordCount == 0)) {
338 char *tmp = (char *)smb;
339 /* Need to work around a bug in two servers here */
340 /* First, check if the part of bcc they sent was zero */
341 if (tmp[sizeof(struct smb_hdr)] == 0) {
342 /* some servers return only half of bcc
343 * on simple responses (wct, bcc both zero)
344 * in particular have seen this on
345 * ulogoffX and FindClose. This leaves
346 * one byte of bcc potentially unitialized
347 */
348 /* zero rest of bcc */
349 tmp[sizeof(struct smb_hdr)+1] = 0;
350 return 0;
351 }
352 cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
353 } else {
354 cifs_dbg(VFS, "Length less than smb header size\n");
355 }
356 return -EIO;
357 }
358
359 /* otherwise, there is enough to get to the BCC */
360 if (check_smb_hdr(smb))
361 return -EIO;
362 clc_len = smbCalcSize(smb, server);
363
364 if (4 + rfclen != total_read) {
365 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
366 rfclen);
367 return -EIO;
368 }
369
370 if (4 + rfclen != clc_len) {
371 __u16 mid = get_mid(smb);
372 /* check if bcc wrapped around for large read responses */
373 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
374 /* check if lengths match mod 64K */
375 if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
376 return 0; /* bcc wrapped */
377 }
378 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
379 clc_len, 4 + rfclen, mid);
380
381 if (4 + rfclen < clc_len) {
382 cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
383 rfclen, mid);
384 return -EIO;
385 } else if (rfclen > clc_len + 512) {
386 /*
387 * Some servers (Windows XP in particular) send more
388 * data than the lengths in the SMB packet would
389 * indicate on certain calls (byte range locks and
390 * trans2 find first calls in particular). While the
391 * client can handle such a frame by ignoring the
392 * trailing data, we choose limit the amount of extra
393 * data to 512 bytes.
394 */
395 cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
396 rfclen, mid);
397 return -EIO;
398 }
399 }
400 return 0;
401 }
402
403 bool
is_valid_oplock_break(char * buffer,struct TCP_Server_Info * srv)404 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
405 {
406 struct smb_hdr *buf = (struct smb_hdr *)buffer;
407 struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
408 struct list_head *tmp, *tmp1, *tmp2;
409 struct cifs_ses *ses;
410 struct cifs_tcon *tcon;
411 struct cifsInodeInfo *pCifsInode;
412 struct cifsFileInfo *netfile;
413
414 cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
415 if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
416 (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
417 struct smb_com_transaction_change_notify_rsp *pSMBr =
418 (struct smb_com_transaction_change_notify_rsp *)buf;
419 struct file_notify_information *pnotify;
420 __u32 data_offset = 0;
421 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
422
423 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
424 data_offset = le32_to_cpu(pSMBr->DataOffset);
425
426 if (data_offset >
427 len - sizeof(struct file_notify_information)) {
428 cifs_dbg(FYI, "Invalid data_offset %u\n",
429 data_offset);
430 return true;
431 }
432 pnotify = (struct file_notify_information *)
433 ((char *)&pSMBr->hdr.Protocol + data_offset);
434 cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
435 pnotify->FileName, pnotify->Action);
436 /* cifs_dump_mem("Rcvd notify Data: ",buf,
437 sizeof(struct smb_hdr)+60); */
438 return true;
439 }
440 if (pSMBr->hdr.Status.CifsError) {
441 cifs_dbg(FYI, "notify err 0x%x\n",
442 pSMBr->hdr.Status.CifsError);
443 return true;
444 }
445 return false;
446 }
447 if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
448 return false;
449 if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
450 /* no sense logging error on invalid handle on oplock
451 break - harmless race between close request and oplock
452 break response is expected from time to time writing out
453 large dirty files cached on the client */
454 if ((NT_STATUS_INVALID_HANDLE) ==
455 le32_to_cpu(pSMB->hdr.Status.CifsError)) {
456 cifs_dbg(FYI, "Invalid handle on oplock break\n");
457 return true;
458 } else if (ERRbadfid ==
459 le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
460 return true;
461 } else {
462 return false; /* on valid oplock brk we get "request" */
463 }
464 }
465 if (pSMB->hdr.WordCount != 8)
466 return false;
467
468 cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
469 pSMB->LockType, pSMB->OplockLevel);
470 if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
471 return false;
472
473 /* look up tcon based on tid & uid */
474 spin_lock(&cifs_tcp_ses_lock);
475 list_for_each(tmp, &srv->smb_ses_list) {
476 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
477 list_for_each(tmp1, &ses->tcon_list) {
478 tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
479 if (tcon->tid != buf->Tid)
480 continue;
481
482 cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
483 spin_lock(&tcon->open_file_lock);
484 list_for_each(tmp2, &tcon->openFileList) {
485 netfile = list_entry(tmp2, struct cifsFileInfo,
486 tlist);
487 if (pSMB->Fid != netfile->fid.netfid)
488 continue;
489
490 cifs_dbg(FYI, "file id match, oplock break\n");
491 pCifsInode = CIFS_I(d_inode(netfile->dentry));
492
493 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
494 &pCifsInode->flags);
495
496 netfile->oplock_epoch = 0;
497 netfile->oplock_level = pSMB->OplockLevel;
498 netfile->oplock_break_cancelled = false;
499 cifs_queue_oplock_break(netfile);
500
501 spin_unlock(&tcon->open_file_lock);
502 spin_unlock(&cifs_tcp_ses_lock);
503 return true;
504 }
505 spin_unlock(&tcon->open_file_lock);
506 spin_unlock(&cifs_tcp_ses_lock);
507 cifs_dbg(FYI, "No matching file for oplock break\n");
508 return true;
509 }
510 }
511 spin_unlock(&cifs_tcp_ses_lock);
512 cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
513 return true;
514 }
515
516 void
dump_smb(void * buf,int smb_buf_length)517 dump_smb(void *buf, int smb_buf_length)
518 {
519 if (traceSMB == 0)
520 return;
521
522 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
523 smb_buf_length, true);
524 }
525
526 void
cifs_autodisable_serverino(struct cifs_sb_info * cifs_sb)527 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
528 {
529 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
530 struct cifs_tcon *tcon = NULL;
531
532 if (cifs_sb->master_tlink)
533 tcon = cifs_sb_master_tcon(cifs_sb);
534
535 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
536 cifs_sb->mnt_cifs_serverino_autodisabled = true;
537 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
538 tcon ? tcon->treeName : "new server");
539 cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
540 cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
541
542 }
543 }
544
cifs_set_oplock_level(struct cifsInodeInfo * cinode,__u32 oplock)545 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
546 {
547 oplock &= 0xF;
548
549 if (oplock == OPLOCK_EXCLUSIVE) {
550 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
551 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
552 &cinode->vfs_inode);
553 } else if (oplock == OPLOCK_READ) {
554 cinode->oplock = CIFS_CACHE_READ_FLG;
555 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
556 &cinode->vfs_inode);
557 } else
558 cinode->oplock = 0;
559 }
560
561 /*
562 * We wait for oplock breaks to be processed before we attempt to perform
563 * writes.
564 */
cifs_get_writer(struct cifsInodeInfo * cinode)565 int cifs_get_writer(struct cifsInodeInfo *cinode)
566 {
567 int rc;
568
569 start:
570 rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
571 TASK_KILLABLE);
572 if (rc)
573 return rc;
574
575 spin_lock(&cinode->writers_lock);
576 if (!cinode->writers)
577 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
578 cinode->writers++;
579 /* Check to see if we have started servicing an oplock break */
580 if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
581 cinode->writers--;
582 if (cinode->writers == 0) {
583 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
584 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
585 }
586 spin_unlock(&cinode->writers_lock);
587 goto start;
588 }
589 spin_unlock(&cinode->writers_lock);
590 return 0;
591 }
592
cifs_put_writer(struct cifsInodeInfo * cinode)593 void cifs_put_writer(struct cifsInodeInfo *cinode)
594 {
595 spin_lock(&cinode->writers_lock);
596 cinode->writers--;
597 if (cinode->writers == 0) {
598 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
599 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
600 }
601 spin_unlock(&cinode->writers_lock);
602 }
603
604 /**
605 * cifs_queue_oplock_break - queue the oplock break handler for cfile
606 *
607 * This function is called from the demultiplex thread when it
608 * receives an oplock break for @cfile.
609 *
610 * Assumes the tcon->open_file_lock is held.
611 * Assumes cfile->file_info_lock is NOT held.
612 */
cifs_queue_oplock_break(struct cifsFileInfo * cfile)613 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
614 {
615 /*
616 * Bump the handle refcount now while we hold the
617 * open_file_lock to enforce the validity of it for the oplock
618 * break handler. The matching put is done at the end of the
619 * handler.
620 */
621 cifsFileInfo_get(cfile);
622
623 queue_work(cifsoplockd_wq, &cfile->oplock_break);
624 }
625
cifs_done_oplock_break(struct cifsInodeInfo * cinode)626 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
627 {
628 clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
629 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
630 }
631
632 bool
backup_cred(struct cifs_sb_info * cifs_sb)633 backup_cred(struct cifs_sb_info *cifs_sb)
634 {
635 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
636 if (uid_eq(cifs_sb->ctx->backupuid, current_fsuid()))
637 return true;
638 }
639 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
640 if (in_group_p(cifs_sb->ctx->backupgid))
641 return true;
642 }
643
644 return false;
645 }
646
647 void
cifs_del_pending_open(struct cifs_pending_open * open)648 cifs_del_pending_open(struct cifs_pending_open *open)
649 {
650 spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
651 list_del(&open->olist);
652 spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
653 }
654
655 void
cifs_add_pending_open_locked(struct cifs_fid * fid,struct tcon_link * tlink,struct cifs_pending_open * open)656 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
657 struct cifs_pending_open *open)
658 {
659 memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
660 open->oplock = CIFS_OPLOCK_NO_CHANGE;
661 open->tlink = tlink;
662 fid->pending_open = open;
663 list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
664 }
665
666 void
cifs_add_pending_open(struct cifs_fid * fid,struct tcon_link * tlink,struct cifs_pending_open * open)667 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
668 struct cifs_pending_open *open)
669 {
670 spin_lock(&tlink_tcon(tlink)->open_file_lock);
671 cifs_add_pending_open_locked(fid, tlink, open);
672 spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
673 }
674
675 bool
cifs_is_deferred_close(struct cifsFileInfo * cfile,struct cifs_deferred_close ** pdclose)676 cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
677 {
678 struct cifs_deferred_close *dclose;
679
680 list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
681 if ((dclose->netfid == cfile->fid.netfid) &&
682 (dclose->persistent_fid == cfile->fid.persistent_fid) &&
683 (dclose->volatile_fid == cfile->fid.volatile_fid)) {
684 *pdclose = dclose;
685 return true;
686 }
687 }
688 return false;
689 }
690
691 void
cifs_add_deferred_close(struct cifsFileInfo * cfile,struct cifs_deferred_close * dclose)692 cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
693 {
694 bool is_deferred = false;
695 struct cifs_deferred_close *pdclose;
696
697 is_deferred = cifs_is_deferred_close(cfile, &pdclose);
698 if (is_deferred) {
699 kfree(dclose);
700 return;
701 }
702
703 dclose->tlink = cfile->tlink;
704 dclose->netfid = cfile->fid.netfid;
705 dclose->persistent_fid = cfile->fid.persistent_fid;
706 dclose->volatile_fid = cfile->fid.volatile_fid;
707 list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
708 }
709
710 void
cifs_del_deferred_close(struct cifsFileInfo * cfile)711 cifs_del_deferred_close(struct cifsFileInfo *cfile)
712 {
713 bool is_deferred = false;
714 struct cifs_deferred_close *dclose;
715
716 is_deferred = cifs_is_deferred_close(cfile, &dclose);
717 if (!is_deferred)
718 return;
719 list_del(&dclose->dlist);
720 kfree(dclose);
721 }
722
723 void
cifs_close_deferred_file(struct cifsInodeInfo * cifs_inode)724 cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
725 {
726 struct cifsFileInfo *cfile = NULL;
727 struct cifs_deferred_close *dclose;
728
729 list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
730 spin_lock(&cifs_inode->deferred_lock);
731 if (cifs_is_deferred_close(cfile, &dclose))
732 mod_delayed_work(deferredclose_wq, &cfile->deferred, 0);
733 spin_unlock(&cifs_inode->deferred_lock);
734 }
735 }
736
737 void
cifs_close_all_deferred_files(struct cifs_tcon * tcon)738 cifs_close_all_deferred_files(struct cifs_tcon *tcon)
739 {
740 struct cifsFileInfo *cfile;
741 struct cifsInodeInfo *cinode;
742 struct list_head *tmp;
743
744 spin_lock(&tcon->open_file_lock);
745 list_for_each(tmp, &tcon->openFileList) {
746 cfile = list_entry(tmp, struct cifsFileInfo, tlist);
747 cinode = CIFS_I(d_inode(cfile->dentry));
748 if (delayed_work_pending(&cfile->deferred))
749 mod_delayed_work(deferredclose_wq, &cfile->deferred, 0);
750 }
751 spin_unlock(&tcon->open_file_lock);
752 }
753
754 /* parses DFS refferal V3 structure
755 * caller is responsible for freeing target_nodes
756 * returns:
757 * - on success - 0
758 * - on failure - errno
759 */
760 int
parse_dfs_referrals(struct get_dfs_referral_rsp * rsp,u32 rsp_size,unsigned int * num_of_nodes,struct dfs_info3_param ** target_nodes,const struct nls_table * nls_codepage,int remap,const char * searchName,bool is_unicode)761 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
762 unsigned int *num_of_nodes,
763 struct dfs_info3_param **target_nodes,
764 const struct nls_table *nls_codepage, int remap,
765 const char *searchName, bool is_unicode)
766 {
767 int i, rc = 0;
768 char *data_end;
769 struct dfs_referral_level_3 *ref;
770
771 *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
772
773 if (*num_of_nodes < 1) {
774 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
775 *num_of_nodes);
776 rc = -EINVAL;
777 goto parse_DFS_referrals_exit;
778 }
779
780 ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
781 if (ref->VersionNumber != cpu_to_le16(3)) {
782 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
783 le16_to_cpu(ref->VersionNumber));
784 rc = -EINVAL;
785 goto parse_DFS_referrals_exit;
786 }
787
788 /* get the upper boundary of the resp buffer */
789 data_end = (char *)rsp + rsp_size;
790
791 cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
792 *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
793
794 *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
795 GFP_KERNEL);
796 if (*target_nodes == NULL) {
797 rc = -ENOMEM;
798 goto parse_DFS_referrals_exit;
799 }
800
801 /* collect necessary data from referrals */
802 for (i = 0; i < *num_of_nodes; i++) {
803 char *temp;
804 int max_len;
805 struct dfs_info3_param *node = (*target_nodes)+i;
806
807 node->flags = le32_to_cpu(rsp->DFSFlags);
808 if (is_unicode) {
809 __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
810 GFP_KERNEL);
811 if (tmp == NULL) {
812 rc = -ENOMEM;
813 goto parse_DFS_referrals_exit;
814 }
815 cifsConvertToUTF16((__le16 *) tmp, searchName,
816 PATH_MAX, nls_codepage, remap);
817 node->path_consumed = cifs_utf16_bytes(tmp,
818 le16_to_cpu(rsp->PathConsumed),
819 nls_codepage);
820 kfree(tmp);
821 } else
822 node->path_consumed = le16_to_cpu(rsp->PathConsumed);
823
824 node->server_type = le16_to_cpu(ref->ServerType);
825 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
826
827 /* copy DfsPath */
828 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
829 max_len = data_end - temp;
830 node->path_name = cifs_strndup_from_utf16(temp, max_len,
831 is_unicode, nls_codepage);
832 if (!node->path_name) {
833 rc = -ENOMEM;
834 goto parse_DFS_referrals_exit;
835 }
836
837 /* copy link target UNC */
838 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
839 max_len = data_end - temp;
840 node->node_name = cifs_strndup_from_utf16(temp, max_len,
841 is_unicode, nls_codepage);
842 if (!node->node_name) {
843 rc = -ENOMEM;
844 goto parse_DFS_referrals_exit;
845 }
846
847 node->ttl = le32_to_cpu(ref->TimeToLive);
848
849 ref++;
850 }
851
852 parse_DFS_referrals_exit:
853 if (rc) {
854 free_dfs_info_array(*target_nodes, *num_of_nodes);
855 *target_nodes = NULL;
856 *num_of_nodes = 0;
857 }
858 return rc;
859 }
860
861 struct cifs_aio_ctx *
cifs_aio_ctx_alloc(void)862 cifs_aio_ctx_alloc(void)
863 {
864 struct cifs_aio_ctx *ctx;
865
866 /*
867 * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
868 * to false so that we know when we have to unreference pages within
869 * cifs_aio_ctx_release()
870 */
871 ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
872 if (!ctx)
873 return NULL;
874
875 INIT_LIST_HEAD(&ctx->list);
876 mutex_init(&ctx->aio_mutex);
877 init_completion(&ctx->done);
878 kref_init(&ctx->refcount);
879 return ctx;
880 }
881
882 void
cifs_aio_ctx_release(struct kref * refcount)883 cifs_aio_ctx_release(struct kref *refcount)
884 {
885 struct cifs_aio_ctx *ctx = container_of(refcount,
886 struct cifs_aio_ctx, refcount);
887
888 cifsFileInfo_put(ctx->cfile);
889
890 /*
891 * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
892 * which means that iov_iter_get_pages() was a success and thus that
893 * we have taken reference on pages.
894 */
895 if (ctx->bv) {
896 unsigned i;
897
898 for (i = 0; i < ctx->npages; i++) {
899 if (ctx->should_dirty)
900 set_page_dirty(ctx->bv[i].bv_page);
901 put_page(ctx->bv[i].bv_page);
902 }
903 kvfree(ctx->bv);
904 }
905
906 kfree(ctx);
907 }
908
909 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
910
911 int
setup_aio_ctx_iter(struct cifs_aio_ctx * ctx,struct iov_iter * iter,int rw)912 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
913 {
914 ssize_t rc;
915 unsigned int cur_npages;
916 unsigned int npages = 0;
917 unsigned int i;
918 size_t len;
919 size_t count = iov_iter_count(iter);
920 unsigned int saved_len;
921 size_t start;
922 unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
923 struct page **pages = NULL;
924 struct bio_vec *bv = NULL;
925
926 if (iov_iter_is_kvec(iter)) {
927 memcpy(&ctx->iter, iter, sizeof(*iter));
928 ctx->len = count;
929 iov_iter_advance(iter, count);
930 return 0;
931 }
932
933 if (array_size(max_pages, sizeof(*bv)) <= CIFS_AIO_KMALLOC_LIMIT)
934 bv = kmalloc_array(max_pages, sizeof(*bv), GFP_KERNEL);
935
936 if (!bv) {
937 bv = vmalloc(array_size(max_pages, sizeof(*bv)));
938 if (!bv)
939 return -ENOMEM;
940 }
941
942 if (array_size(max_pages, sizeof(*pages)) <= CIFS_AIO_KMALLOC_LIMIT)
943 pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
944
945 if (!pages) {
946 pages = vmalloc(array_size(max_pages, sizeof(*pages)));
947 if (!pages) {
948 kvfree(bv);
949 return -ENOMEM;
950 }
951 }
952
953 saved_len = count;
954
955 while (count && npages < max_pages) {
956 rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
957 if (rc < 0) {
958 cifs_dbg(VFS, "Couldn't get user pages (rc=%zd)\n", rc);
959 break;
960 }
961
962 if (rc > count) {
963 cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
964 count);
965 break;
966 }
967
968 iov_iter_advance(iter, rc);
969 count -= rc;
970 rc += start;
971 cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
972
973 if (npages + cur_npages > max_pages) {
974 cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
975 npages + cur_npages, max_pages);
976 break;
977 }
978
979 for (i = 0; i < cur_npages; i++) {
980 len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
981 bv[npages + i].bv_page = pages[i];
982 bv[npages + i].bv_offset = start;
983 bv[npages + i].bv_len = len - start;
984 rc -= len;
985 start = 0;
986 }
987
988 npages += cur_npages;
989 }
990
991 kvfree(pages);
992 ctx->bv = bv;
993 ctx->len = saved_len - count;
994 ctx->npages = npages;
995 iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len);
996 return 0;
997 }
998
999 /**
1000 * cifs_alloc_hash - allocate hash and hash context together
1001 *
1002 * The caller has to make sure @sdesc is initialized to either NULL or
1003 * a valid context. Both can be freed via cifs_free_hash().
1004 */
1005 int
cifs_alloc_hash(const char * name,struct crypto_shash ** shash,struct sdesc ** sdesc)1006 cifs_alloc_hash(const char *name,
1007 struct crypto_shash **shash, struct sdesc **sdesc)
1008 {
1009 int rc = 0;
1010 size_t size;
1011
1012 if (*sdesc != NULL)
1013 return 0;
1014
1015 *shash = crypto_alloc_shash(name, 0, 0);
1016 if (IS_ERR(*shash)) {
1017 cifs_dbg(VFS, "Could not allocate crypto %s\n", name);
1018 rc = PTR_ERR(*shash);
1019 *shash = NULL;
1020 *sdesc = NULL;
1021 return rc;
1022 }
1023
1024 size = sizeof(struct shash_desc) + crypto_shash_descsize(*shash);
1025 *sdesc = kmalloc(size, GFP_KERNEL);
1026 if (*sdesc == NULL) {
1027 cifs_dbg(VFS, "no memory left to allocate crypto %s\n", name);
1028 crypto_free_shash(*shash);
1029 *shash = NULL;
1030 return -ENOMEM;
1031 }
1032
1033 (*sdesc)->shash.tfm = *shash;
1034 return 0;
1035 }
1036
1037 /**
1038 * cifs_free_hash - free hash and hash context together
1039 *
1040 * Freeing a NULL hash or context is safe.
1041 */
1042 void
cifs_free_hash(struct crypto_shash ** shash,struct sdesc ** sdesc)1043 cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc)
1044 {
1045 kfree(*sdesc);
1046 *sdesc = NULL;
1047 if (*shash)
1048 crypto_free_shash(*shash);
1049 *shash = NULL;
1050 }
1051
1052 /**
1053 * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
1054 * Input: rqst - a smb_rqst, page - a page index for rqst
1055 * Output: *len - the length for this page, *offset - the offset for this page
1056 */
rqst_page_get_length(struct smb_rqst * rqst,unsigned int page,unsigned int * len,unsigned int * offset)1057 void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page,
1058 unsigned int *len, unsigned int *offset)
1059 {
1060 *len = rqst->rq_pagesz;
1061 *offset = (page == 0) ? rqst->rq_offset : 0;
1062
1063 if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
1064 *len = rqst->rq_tailsz;
1065 else if (page == 0)
1066 *len = rqst->rq_pagesz - rqst->rq_offset;
1067 }
1068
extract_unc_hostname(const char * unc,const char ** h,size_t * len)1069 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
1070 {
1071 const char *end;
1072
1073 /* skip initial slashes */
1074 while (*unc && (*unc == '\\' || *unc == '/'))
1075 unc++;
1076
1077 end = unc;
1078
1079 while (*end && !(*end == '\\' || *end == '/'))
1080 end++;
1081
1082 *h = unc;
1083 *len = end - unc;
1084 }
1085
1086 /**
1087 * copy_path_name - copy src path to dst, possibly truncating
1088 *
1089 * returns number of bytes written (including trailing nul)
1090 */
copy_path_name(char * dst,const char * src)1091 int copy_path_name(char *dst, const char *src)
1092 {
1093 int name_len;
1094
1095 /*
1096 * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1097 * will truncate and strlen(dst) will be PATH_MAX-1
1098 */
1099 name_len = strscpy(dst, src, PATH_MAX);
1100 if (WARN_ON_ONCE(name_len < 0))
1101 name_len = PATH_MAX-1;
1102
1103 /* we count the trailing nul */
1104 name_len++;
1105 return name_len;
1106 }
1107
1108 struct super_cb_data {
1109 void *data;
1110 struct super_block *sb;
1111 };
1112
tcp_super_cb(struct super_block * sb,void * arg)1113 static void tcp_super_cb(struct super_block *sb, void *arg)
1114 {
1115 struct super_cb_data *sd = arg;
1116 struct TCP_Server_Info *server = sd->data;
1117 struct cifs_sb_info *cifs_sb;
1118 struct cifs_tcon *tcon;
1119
1120 if (sd->sb)
1121 return;
1122
1123 cifs_sb = CIFS_SB(sb);
1124 tcon = cifs_sb_master_tcon(cifs_sb);
1125 if (tcon->ses->server == server)
1126 sd->sb = sb;
1127 }
1128
__cifs_get_super(void (* f)(struct super_block *,void *),void * data)1129 static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1130 void *data)
1131 {
1132 struct super_cb_data sd = {
1133 .data = data,
1134 .sb = NULL,
1135 };
1136
1137 iterate_supers_type(&cifs_fs_type, f, &sd);
1138
1139 if (!sd.sb)
1140 return ERR_PTR(-EINVAL);
1141 /*
1142 * Grab an active reference in order to prevent automounts (DFS links)
1143 * of expiring and then freeing up our cifs superblock pointer while
1144 * we're doing failover.
1145 */
1146 cifs_sb_active(sd.sb);
1147 return sd.sb;
1148 }
1149
__cifs_put_super(struct super_block * sb)1150 static void __cifs_put_super(struct super_block *sb)
1151 {
1152 if (!IS_ERR_OR_NULL(sb))
1153 cifs_sb_deactive(sb);
1154 }
1155
cifs_get_tcp_super(struct TCP_Server_Info * server)1156 struct super_block *cifs_get_tcp_super(struct TCP_Server_Info *server)
1157 {
1158 return __cifs_get_super(tcp_super_cb, server);
1159 }
1160
cifs_put_tcp_super(struct super_block * sb)1161 void cifs_put_tcp_super(struct super_block *sb)
1162 {
1163 __cifs_put_super(sb);
1164 }
1165
1166 #ifdef CONFIG_CIFS_DFS_UPCALL
match_target_ip(struct TCP_Server_Info * server,const char * share,size_t share_len,bool * result)1167 int match_target_ip(struct TCP_Server_Info *server,
1168 const char *share, size_t share_len,
1169 bool *result)
1170 {
1171 int rc;
1172 char *target, *tip = NULL;
1173 struct sockaddr tipaddr;
1174
1175 *result = false;
1176
1177 target = kzalloc(share_len + 3, GFP_KERNEL);
1178 if (!target) {
1179 rc = -ENOMEM;
1180 goto out;
1181 }
1182
1183 scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
1184
1185 cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
1186
1187 rc = dns_resolve_server_name_to_ip(target, &tip);
1188 if (rc < 0)
1189 goto out;
1190
1191 cifs_dbg(FYI, "%s: target ip: %s\n", __func__, tip);
1192
1193 if (!cifs_convert_address(&tipaddr, tip, strlen(tip))) {
1194 cifs_dbg(VFS, "%s: failed to convert target ip address\n",
1195 __func__);
1196 rc = -EINVAL;
1197 goto out;
1198 }
1199
1200 *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr,
1201 &tipaddr);
1202 cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
1203 rc = 0;
1204
1205 out:
1206 kfree(target);
1207 kfree(tip);
1208
1209 return rc;
1210 }
1211
tcon_super_cb(struct super_block * sb,void * arg)1212 static void tcon_super_cb(struct super_block *sb, void *arg)
1213 {
1214 struct super_cb_data *sd = arg;
1215 struct cifs_tcon *tcon = sd->data;
1216 struct cifs_sb_info *cifs_sb;
1217
1218 if (sd->sb)
1219 return;
1220
1221 cifs_sb = CIFS_SB(sb);
1222 if (tcon->dfs_path && cifs_sb->origin_fullpath &&
1223 !strcasecmp(tcon->dfs_path, cifs_sb->origin_fullpath))
1224 sd->sb = sb;
1225 }
1226
cifs_get_tcon_super(struct cifs_tcon * tcon)1227 static inline struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon)
1228 {
1229 return __cifs_get_super(tcon_super_cb, tcon);
1230 }
1231
cifs_put_tcon_super(struct super_block * sb)1232 static inline void cifs_put_tcon_super(struct super_block *sb)
1233 {
1234 __cifs_put_super(sb);
1235 }
1236 #else
cifs_get_tcon_super(struct cifs_tcon * tcon)1237 static inline struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon)
1238 {
1239 return ERR_PTR(-EOPNOTSUPP);
1240 }
1241
cifs_put_tcon_super(struct super_block * sb)1242 static inline void cifs_put_tcon_super(struct super_block *sb)
1243 {
1244 }
1245 #endif
1246
update_super_prepath(struct cifs_tcon * tcon,char * prefix)1247 int update_super_prepath(struct cifs_tcon *tcon, char *prefix)
1248 {
1249 struct super_block *sb;
1250 struct cifs_sb_info *cifs_sb;
1251 int rc = 0;
1252
1253 sb = cifs_get_tcon_super(tcon);
1254 if (IS_ERR(sb))
1255 return PTR_ERR(sb);
1256
1257 cifs_sb = CIFS_SB(sb);
1258
1259 kfree(cifs_sb->prepath);
1260
1261 if (prefix && *prefix) {
1262 cifs_sb->prepath = kstrdup(prefix, GFP_ATOMIC);
1263 if (!cifs_sb->prepath) {
1264 rc = -ENOMEM;
1265 goto out;
1266 }
1267
1268 convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1269 } else
1270 cifs_sb->prepath = NULL;
1271
1272 cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1273
1274 out:
1275 cifs_put_tcon_super(sb);
1276 return rc;
1277 }
1278