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TOMOYO Linux Cross Reference
Linux/fs/cifs/misc.c

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  1 // SPDX-License-Identifier: LGPL-2.1
  2 /*
  3  *   fs/cifs/misc.c
  4  *
  5  *   Copyright (C) International Business Machines  Corp., 2002,2008
  6  *   Author(s): Steve French (sfrench@us.ibm.com)
  7  *
  8  */
  9 
 10 #include <linux/slab.h>
 11 #include <linux/ctype.h>
 12 #include <linux/mempool.h>
 13 #include <linux/vmalloc.h>
 14 #include "cifspdu.h"
 15 #include "cifsglob.h"
 16 #include "cifsproto.h"
 17 #include "cifs_debug.h"
 18 #include "smberr.h"
 19 #include "nterr.h"
 20 #include "cifs_unicode.h"
 21 #include "smb2pdu.h"
 22 #include "cifsfs.h"
 23 #ifdef CONFIG_CIFS_DFS_UPCALL
 24 #include "dns_resolve.h"
 25 #endif
 26 #include "fs_context.h"
 27 
 28 extern mempool_t *cifs_sm_req_poolp;
 29 extern mempool_t *cifs_req_poolp;
 30 
 31 /* The xid serves as a useful identifier for each incoming vfs request,
 32    in a similar way to the mid which is useful to track each sent smb,
 33    and CurrentXid can also provide a running counter (although it
 34    will eventually wrap past zero) of the total vfs operations handled
 35    since the cifs fs was mounted */
 36 
 37 unsigned int
 38 _get_xid(void)
 39 {
 40         unsigned int xid;
 41 
 42         spin_lock(&GlobalMid_Lock);
 43         GlobalTotalActiveXid++;
 44 
 45         /* keep high water mark for number of simultaneous ops in filesystem */
 46         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
 47                 GlobalMaxActiveXid = GlobalTotalActiveXid;
 48         if (GlobalTotalActiveXid > 65000)
 49                 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
 50         xid = GlobalCurrentXid++;
 51         spin_unlock(&GlobalMid_Lock);
 52         return xid;
 53 }
 54 
 55 void
 56 _free_xid(unsigned int xid)
 57 {
 58         spin_lock(&GlobalMid_Lock);
 59         /* if (GlobalTotalActiveXid == 0)
 60                 BUG(); */
 61         GlobalTotalActiveXid--;
 62         spin_unlock(&GlobalMid_Lock);
 63 }
 64 
 65 struct cifs_ses *
 66 sesInfoAlloc(void)
 67 {
 68         struct cifs_ses *ret_buf;
 69 
 70         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
 71         if (ret_buf) {
 72                 atomic_inc(&sesInfoAllocCount);
 73                 ret_buf->status = CifsNew;
 74                 ++ret_buf->ses_count;
 75                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
 76                 INIT_LIST_HEAD(&ret_buf->tcon_list);
 77                 mutex_init(&ret_buf->session_mutex);
 78                 spin_lock_init(&ret_buf->iface_lock);
 79         }
 80         return ret_buf;
 81 }
 82 
 83 void
 84 sesInfoFree(struct cifs_ses *buf_to_free)
 85 {
 86         if (buf_to_free == NULL) {
 87                 cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
 88                 return;
 89         }
 90 
 91         atomic_dec(&sesInfoAllocCount);
 92         kfree(buf_to_free->serverOS);
 93         kfree(buf_to_free->serverDomain);
 94         kfree(buf_to_free->serverNOS);
 95         kfree_sensitive(buf_to_free->password);
 96         kfree(buf_to_free->user_name);
 97         kfree(buf_to_free->domainName);
 98         kfree_sensitive(buf_to_free->auth_key.response);
 99         kfree(buf_to_free->iface_list);
100         kfree_sensitive(buf_to_free);
101 }
102 
103 struct cifs_tcon *
104 tconInfoAlloc(void)
105 {
106         struct cifs_tcon *ret_buf;
107 
108         ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
109         if (!ret_buf)
110                 return NULL;
111         ret_buf->crfid.fid = kzalloc(sizeof(*ret_buf->crfid.fid), GFP_KERNEL);
112         if (!ret_buf->crfid.fid) {
113                 kfree(ret_buf);
114                 return NULL;
115         }
116 
117         atomic_inc(&tconInfoAllocCount);
118         ret_buf->tidStatus = CifsNew;
119         ++ret_buf->tc_count;
120         INIT_LIST_HEAD(&ret_buf->openFileList);
121         INIT_LIST_HEAD(&ret_buf->tcon_list);
122         spin_lock_init(&ret_buf->open_file_lock);
123         mutex_init(&ret_buf->crfid.fid_mutex);
124         spin_lock_init(&ret_buf->stat_lock);
125         atomic_set(&ret_buf->num_local_opens, 0);
126         atomic_set(&ret_buf->num_remote_opens, 0);
127 
128         return ret_buf;
129 }
130 
131 void
132 tconInfoFree(struct cifs_tcon *buf_to_free)
133 {
134         if (buf_to_free == NULL) {
135                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
136                 return;
137         }
138         atomic_dec(&tconInfoAllocCount);
139         kfree(buf_to_free->nativeFileSystem);
140         kfree_sensitive(buf_to_free->password);
141         kfree(buf_to_free->crfid.fid);
142 #ifdef CONFIG_CIFS_DFS_UPCALL
143         kfree(buf_to_free->dfs_path);
144 #endif
145         kfree(buf_to_free);
146 }
147 
148 struct smb_hdr *
149 cifs_buf_get(void)
150 {
151         struct smb_hdr *ret_buf = NULL;
152         /*
153          * SMB2 header is bigger than CIFS one - no problems to clean some
154          * more bytes for CIFS.
155          */
156         size_t buf_size = sizeof(struct smb2_sync_hdr);
157 
158         /*
159          * We could use negotiated size instead of max_msgsize -
160          * but it may be more efficient to always alloc same size
161          * albeit slightly larger than necessary and maxbuffersize
162          * defaults to this and can not be bigger.
163          */
164         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
165 
166         /* clear the first few header bytes */
167         /* for most paths, more is cleared in header_assemble */
168         memset(ret_buf, 0, buf_size + 3);
169         atomic_inc(&bufAllocCount);
170 #ifdef CONFIG_CIFS_STATS2
171         atomic_inc(&totBufAllocCount);
172 #endif /* CONFIG_CIFS_STATS2 */
173 
174         return ret_buf;
175 }
176 
177 void
178 cifs_buf_release(void *buf_to_free)
179 {
180         if (buf_to_free == NULL) {
181                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
182                 return;
183         }
184         mempool_free(buf_to_free, cifs_req_poolp);
185 
186         atomic_dec(&bufAllocCount);
187         return;
188 }
189 
190 struct smb_hdr *
191 cifs_small_buf_get(void)
192 {
193         struct smb_hdr *ret_buf = NULL;
194 
195 /* We could use negotiated size instead of max_msgsize -
196    but it may be more efficient to always alloc same size
197    albeit slightly larger than necessary and maxbuffersize
198    defaults to this and can not be bigger */
199         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
200         /* No need to clear memory here, cleared in header assemble */
201         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
202         atomic_inc(&smBufAllocCount);
203 #ifdef CONFIG_CIFS_STATS2
204         atomic_inc(&totSmBufAllocCount);
205 #endif /* CONFIG_CIFS_STATS2 */
206 
207         return ret_buf;
208 }
209 
210 void
211 cifs_small_buf_release(void *buf_to_free)
212 {
213 
214         if (buf_to_free == NULL) {
215                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
216                 return;
217         }
218         mempool_free(buf_to_free, cifs_sm_req_poolp);
219 
220         atomic_dec(&smBufAllocCount);
221         return;
222 }
223 
224 void
225 free_rsp_buf(int resp_buftype, void *rsp)
226 {
227         if (resp_buftype == CIFS_SMALL_BUFFER)
228                 cifs_small_buf_release(rsp);
229         else if (resp_buftype == CIFS_LARGE_BUFFER)
230                 cifs_buf_release(rsp);
231 }
232 
233 /* NB: MID can not be set if treeCon not passed in, in that
234    case it is responsbility of caller to set the mid */
235 void
236 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
237                 const struct cifs_tcon *treeCon, int word_count
238                 /* length of fixed section (word count) in two byte units  */)
239 {
240         char *temp = (char *) buffer;
241 
242         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
243 
244         buffer->smb_buf_length = cpu_to_be32(
245             (2 * word_count) + sizeof(struct smb_hdr) -
246             4 /*  RFC 1001 length field does not count */  +
247             2 /* for bcc field itself */) ;
248 
249         buffer->Protocol[0] = 0xFF;
250         buffer->Protocol[1] = 'S';
251         buffer->Protocol[2] = 'M';
252         buffer->Protocol[3] = 'B';
253         buffer->Command = smb_command;
254         buffer->Flags = 0x00;   /* case sensitive */
255         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
256         buffer->Pid = cpu_to_le16((__u16)current->tgid);
257         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
258         if (treeCon) {
259                 buffer->Tid = treeCon->tid;
260                 if (treeCon->ses) {
261                         if (treeCon->ses->capabilities & CAP_UNICODE)
262                                 buffer->Flags2 |= SMBFLG2_UNICODE;
263                         if (treeCon->ses->capabilities & CAP_STATUS32)
264                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
265 
266                         /* Uid is not converted */
267                         buffer->Uid = treeCon->ses->Suid;
268                         buffer->Mid = get_next_mid(treeCon->ses->server);
269                 }
270                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
271                         buffer->Flags2 |= SMBFLG2_DFS;
272                 if (treeCon->nocase)
273                         buffer->Flags  |= SMBFLG_CASELESS;
274                 if ((treeCon->ses) && (treeCon->ses->server))
275                         if (treeCon->ses->server->sign)
276                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
277         }
278 
279 /*  endian conversion of flags is now done just before sending */
280         buffer->WordCount = (char) word_count;
281         return;
282 }
283 
284 static int
285 check_smb_hdr(struct smb_hdr *smb)
286 {
287         /* does it have the right SMB "signature" ? */
288         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
289                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
290                          *(unsigned int *)smb->Protocol);
291                 return 1;
292         }
293 
294         /* if it's a response then accept */
295         if (smb->Flags & SMBFLG_RESPONSE)
296                 return 0;
297 
298         /* only one valid case where server sends us request */
299         if (smb->Command == SMB_COM_LOCKING_ANDX)
300                 return 0;
301 
302         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
303                  get_mid(smb));
304         return 1;
305 }
306 
307 int
308 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
309 {
310         struct smb_hdr *smb = (struct smb_hdr *)buf;
311         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
312         __u32 clc_len;  /* calculated length */
313         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
314                  total_read, rfclen);
315 
316         /* is this frame too small to even get to a BCC? */
317         if (total_read < 2 + sizeof(struct smb_hdr)) {
318                 if ((total_read >= sizeof(struct smb_hdr) - 1)
319                             && (smb->Status.CifsError != 0)) {
320                         /* it's an error return */
321                         smb->WordCount = 0;
322                         /* some error cases do not return wct and bcc */
323                         return 0;
324                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
325                                 (smb->WordCount == 0)) {
326                         char *tmp = (char *)smb;
327                         /* Need to work around a bug in two servers here */
328                         /* First, check if the part of bcc they sent was zero */
329                         if (tmp[sizeof(struct smb_hdr)] == 0) {
330                                 /* some servers return only half of bcc
331                                  * on simple responses (wct, bcc both zero)
332                                  * in particular have seen this on
333                                  * ulogoffX and FindClose. This leaves
334                                  * one byte of bcc potentially unitialized
335                                  */
336                                 /* zero rest of bcc */
337                                 tmp[sizeof(struct smb_hdr)+1] = 0;
338                                 return 0;
339                         }
340                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
341                 } else {
342                         cifs_dbg(VFS, "Length less than smb header size\n");
343                 }
344                 return -EIO;
345         }
346 
347         /* otherwise, there is enough to get to the BCC */
348         if (check_smb_hdr(smb))
349                 return -EIO;
350         clc_len = smbCalcSize(smb, server);
351 
352         if (4 + rfclen != total_read) {
353                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
354                          rfclen);
355                 return -EIO;
356         }
357 
358         if (4 + rfclen != clc_len) {
359                 __u16 mid = get_mid(smb);
360                 /* check if bcc wrapped around for large read responses */
361                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
362                         /* check if lengths match mod 64K */
363                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
364                                 return 0; /* bcc wrapped */
365                 }
366                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
367                          clc_len, 4 + rfclen, mid);
368 
369                 if (4 + rfclen < clc_len) {
370                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
371                                  rfclen, mid);
372                         return -EIO;
373                 } else if (rfclen > clc_len + 512) {
374                         /*
375                          * Some servers (Windows XP in particular) send more
376                          * data than the lengths in the SMB packet would
377                          * indicate on certain calls (byte range locks and
378                          * trans2 find first calls in particular). While the
379                          * client can handle such a frame by ignoring the
380                          * trailing data, we choose limit the amount of extra
381                          * data to 512 bytes.
382                          */
383                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
384                                  rfclen, mid);
385                         return -EIO;
386                 }
387         }
388         return 0;
389 }
390 
391 bool
392 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
393 {
394         struct smb_hdr *buf = (struct smb_hdr *)buffer;
395         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
396         struct list_head *tmp, *tmp1, *tmp2;
397         struct cifs_ses *ses;
398         struct cifs_tcon *tcon;
399         struct cifsInodeInfo *pCifsInode;
400         struct cifsFileInfo *netfile;
401 
402         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
403         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
404            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
405                 struct smb_com_transaction_change_notify_rsp *pSMBr =
406                         (struct smb_com_transaction_change_notify_rsp *)buf;
407                 struct file_notify_information *pnotify;
408                 __u32 data_offset = 0;
409                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
410 
411                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
412                         data_offset = le32_to_cpu(pSMBr->DataOffset);
413 
414                         if (data_offset >
415                             len - sizeof(struct file_notify_information)) {
416                                 cifs_dbg(FYI, "Invalid data_offset %u\n",
417                                          data_offset);
418                                 return true;
419                         }
420                         pnotify = (struct file_notify_information *)
421                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
422                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
423                                  pnotify->FileName, pnotify->Action);
424                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
425                                 sizeof(struct smb_hdr)+60); */
426                         return true;
427                 }
428                 if (pSMBr->hdr.Status.CifsError) {
429                         cifs_dbg(FYI, "notify err 0x%x\n",
430                                  pSMBr->hdr.Status.CifsError);
431                         return true;
432                 }
433                 return false;
434         }
435         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
436                 return false;
437         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
438                 /* no sense logging error on invalid handle on oplock
439                    break - harmless race between close request and oplock
440                    break response is expected from time to time writing out
441                    large dirty files cached on the client */
442                 if ((NT_STATUS_INVALID_HANDLE) ==
443                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
444                         cifs_dbg(FYI, "Invalid handle on oplock break\n");
445                         return true;
446                 } else if (ERRbadfid ==
447                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
448                         return true;
449                 } else {
450                         return false; /* on valid oplock brk we get "request" */
451                 }
452         }
453         if (pSMB->hdr.WordCount != 8)
454                 return false;
455 
456         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
457                  pSMB->LockType, pSMB->OplockLevel);
458         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
459                 return false;
460 
461         /* look up tcon based on tid & uid */
462         spin_lock(&cifs_tcp_ses_lock);
463         list_for_each(tmp, &srv->smb_ses_list) {
464                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
465                 list_for_each(tmp1, &ses->tcon_list) {
466                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
467                         if (tcon->tid != buf->Tid)
468                                 continue;
469 
470                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
471                         spin_lock(&tcon->open_file_lock);
472                         list_for_each(tmp2, &tcon->openFileList) {
473                                 netfile = list_entry(tmp2, struct cifsFileInfo,
474                                                      tlist);
475                                 if (pSMB->Fid != netfile->fid.netfid)
476                                         continue;
477 
478                                 cifs_dbg(FYI, "file id match, oplock break\n");
479                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
480 
481                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
482                                         &pCifsInode->flags);
483 
484                                 netfile->oplock_epoch = 0;
485                                 netfile->oplock_level = pSMB->OplockLevel;
486                                 netfile->oplock_break_cancelled = false;
487                                 cifs_queue_oplock_break(netfile);
488 
489                                 spin_unlock(&tcon->open_file_lock);
490                                 spin_unlock(&cifs_tcp_ses_lock);
491                                 return true;
492                         }
493                         spin_unlock(&tcon->open_file_lock);
494                         spin_unlock(&cifs_tcp_ses_lock);
495                         cifs_dbg(FYI, "No matching file for oplock break\n");
496                         return true;
497                 }
498         }
499         spin_unlock(&cifs_tcp_ses_lock);
500         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
501         return true;
502 }
503 
504 void
505 dump_smb(void *buf, int smb_buf_length)
506 {
507         if (traceSMB == 0)
508                 return;
509 
510         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
511                        smb_buf_length, true);
512 }
513 
514 void
515 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
516 {
517         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
518                 struct cifs_tcon *tcon = NULL;
519 
520                 if (cifs_sb->master_tlink)
521                         tcon = cifs_sb_master_tcon(cifs_sb);
522 
523                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
524                 cifs_sb->mnt_cifs_serverino_autodisabled = true;
525                 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
526                          tcon ? tcon->treeName : "new server");
527                 cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
528                 cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
529 
530         }
531 }
532 
533 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
534 {
535         oplock &= 0xF;
536 
537         if (oplock == OPLOCK_EXCLUSIVE) {
538                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
539                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
540                          &cinode->vfs_inode);
541         } else if (oplock == OPLOCK_READ) {
542                 cinode->oplock = CIFS_CACHE_READ_FLG;
543                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
544                          &cinode->vfs_inode);
545         } else
546                 cinode->oplock = 0;
547 }
548 
549 /*
550  * We wait for oplock breaks to be processed before we attempt to perform
551  * writes.
552  */
553 int cifs_get_writer(struct cifsInodeInfo *cinode)
554 {
555         int rc;
556 
557 start:
558         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
559                          TASK_KILLABLE);
560         if (rc)
561                 return rc;
562 
563         spin_lock(&cinode->writers_lock);
564         if (!cinode->writers)
565                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
566         cinode->writers++;
567         /* Check to see if we have started servicing an oplock break */
568         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
569                 cinode->writers--;
570                 if (cinode->writers == 0) {
571                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
572                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
573                 }
574                 spin_unlock(&cinode->writers_lock);
575                 goto start;
576         }
577         spin_unlock(&cinode->writers_lock);
578         return 0;
579 }
580 
581 void cifs_put_writer(struct cifsInodeInfo *cinode)
582 {
583         spin_lock(&cinode->writers_lock);
584         cinode->writers--;
585         if (cinode->writers == 0) {
586                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
587                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
588         }
589         spin_unlock(&cinode->writers_lock);
590 }
591 
592 /**
593  * cifs_queue_oplock_break - queue the oplock break handler for cfile
594  *
595  * This function is called from the demultiplex thread when it
596  * receives an oplock break for @cfile.
597  *
598  * Assumes the tcon->open_file_lock is held.
599  * Assumes cfile->file_info_lock is NOT held.
600  */
601 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
602 {
603         /*
604          * Bump the handle refcount now while we hold the
605          * open_file_lock to enforce the validity of it for the oplock
606          * break handler. The matching put is done at the end of the
607          * handler.
608          */
609         cifsFileInfo_get(cfile);
610 
611         queue_work(cifsoplockd_wq, &cfile->oplock_break);
612 }
613 
614 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
615 {
616         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
617         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
618 }
619 
620 bool
621 backup_cred(struct cifs_sb_info *cifs_sb)
622 {
623         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
624                 if (uid_eq(cifs_sb->ctx->backupuid, current_fsuid()))
625                         return true;
626         }
627         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
628                 if (in_group_p(cifs_sb->ctx->backupgid))
629                         return true;
630         }
631 
632         return false;
633 }
634 
635 void
636 cifs_del_pending_open(struct cifs_pending_open *open)
637 {
638         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
639         list_del(&open->olist);
640         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
641 }
642 
643 void
644 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
645                              struct cifs_pending_open *open)
646 {
647         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
648         open->oplock = CIFS_OPLOCK_NO_CHANGE;
649         open->tlink = tlink;
650         fid->pending_open = open;
651         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
652 }
653 
654 void
655 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
656                       struct cifs_pending_open *open)
657 {
658         spin_lock(&tlink_tcon(tlink)->open_file_lock);
659         cifs_add_pending_open_locked(fid, tlink, open);
660         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
661 }
662 
663 /*
664  * Critical section which runs after acquiring deferred_lock.
665  * As there is no reference count on cifs_deferred_close, pdclose
666  * should not be used outside deferred_lock.
667  */
668 bool
669 cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
670 {
671         struct cifs_deferred_close *dclose;
672 
673         list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
674                 if ((dclose->netfid == cfile->fid.netfid) &&
675                         (dclose->persistent_fid == cfile->fid.persistent_fid) &&
676                         (dclose->volatile_fid == cfile->fid.volatile_fid)) {
677                         *pdclose = dclose;
678                         return true;
679                 }
680         }
681         return false;
682 }
683 
684 /*
685  * Critical section which runs after acquiring deferred_lock.
686  */
687 void
688 cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
689 {
690         bool is_deferred = false;
691         struct cifs_deferred_close *pdclose;
692 
693         is_deferred = cifs_is_deferred_close(cfile, &pdclose);
694         if (is_deferred) {
695                 kfree(dclose);
696                 return;
697         }
698 
699         dclose->tlink = cfile->tlink;
700         dclose->netfid = cfile->fid.netfid;
701         dclose->persistent_fid = cfile->fid.persistent_fid;
702         dclose->volatile_fid = cfile->fid.volatile_fid;
703         list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
704 }
705 
706 /*
707  * Critical section which runs after acquiring deferred_lock.
708  */
709 void
710 cifs_del_deferred_close(struct cifsFileInfo *cfile)
711 {
712         bool is_deferred = false;
713         struct cifs_deferred_close *dclose;
714 
715         is_deferred = cifs_is_deferred_close(cfile, &dclose);
716         if (!is_deferred)
717                 return;
718         list_del(&dclose->dlist);
719         kfree(dclose);
720 }
721 
722 void
723 cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
724 {
725         struct cifsFileInfo *cfile = NULL;
726         struct cifs_deferred_close *dclose;
727 
728         list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
729                 spin_lock(&cifs_inode->deferred_lock);
730                 if (cifs_is_deferred_close(cfile, &dclose))
731                         mod_delayed_work(deferredclose_wq, &cfile->deferred, 0);
732                 spin_unlock(&cifs_inode->deferred_lock);
733         }
734 }
735 
736 void
737 cifs_close_all_deferred_files(struct cifs_tcon *tcon)
738 {
739         struct cifsFileInfo *cfile;
740         struct list_head *tmp;
741 
742         spin_lock(&tcon->open_file_lock);
743         list_for_each(tmp, &tcon->openFileList) {
744                 cfile = list_entry(tmp, struct cifsFileInfo, tlist);
745                 if (delayed_work_pending(&cfile->deferred)) {
746                         /*
747                          * If there is no pending work, mod_delayed_work queues new work.
748                          * So, Increase the ref count to avoid use-after-free.
749                          */
750                         if (!mod_delayed_work(deferredclose_wq, &cfile->deferred, 0))
751                                 cifsFileInfo_get(cfile);
752                 }
753         }
754         spin_unlock(&tcon->open_file_lock);
755 }
756 
757 /* parses DFS refferal V3 structure
758  * caller is responsible for freeing target_nodes
759  * returns:
760  * - on success - 0
761  * - on failure - errno
762  */
763 int
764 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
765                     unsigned int *num_of_nodes,
766                     struct dfs_info3_param **target_nodes,
767                     const struct nls_table *nls_codepage, int remap,
768                     const char *searchName, bool is_unicode)
769 {
770         int i, rc = 0;
771         char *data_end;
772         struct dfs_referral_level_3 *ref;
773 
774         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
775 
776         if (*num_of_nodes < 1) {
777                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
778                          *num_of_nodes);
779                 rc = -EINVAL;
780                 goto parse_DFS_referrals_exit;
781         }
782 
783         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
784         if (ref->VersionNumber != cpu_to_le16(3)) {
785                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
786                          le16_to_cpu(ref->VersionNumber));
787                 rc = -EINVAL;
788                 goto parse_DFS_referrals_exit;
789         }
790 
791         /* get the upper boundary of the resp buffer */
792         data_end = (char *)rsp + rsp_size;
793 
794         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
795                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
796 
797         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
798                                 GFP_KERNEL);
799         if (*target_nodes == NULL) {
800                 rc = -ENOMEM;
801                 goto parse_DFS_referrals_exit;
802         }
803 
804         /* collect necessary data from referrals */
805         for (i = 0; i < *num_of_nodes; i++) {
806                 char *temp;
807                 int max_len;
808                 struct dfs_info3_param *node = (*target_nodes)+i;
809 
810                 node->flags = le32_to_cpu(rsp->DFSFlags);
811                 if (is_unicode) {
812                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
813                                                 GFP_KERNEL);
814                         if (tmp == NULL) {
815                                 rc = -ENOMEM;
816                                 goto parse_DFS_referrals_exit;
817                         }
818                         cifsConvertToUTF16((__le16 *) tmp, searchName,
819                                            PATH_MAX, nls_codepage, remap);
820                         node->path_consumed = cifs_utf16_bytes(tmp,
821                                         le16_to_cpu(rsp->PathConsumed),
822                                         nls_codepage);
823                         kfree(tmp);
824                 } else
825                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
826 
827                 node->server_type = le16_to_cpu(ref->ServerType);
828                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
829 
830                 /* copy DfsPath */
831                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
832                 max_len = data_end - temp;
833                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
834                                                 is_unicode, nls_codepage);
835                 if (!node->path_name) {
836                         rc = -ENOMEM;
837                         goto parse_DFS_referrals_exit;
838                 }
839 
840                 /* copy link target UNC */
841                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
842                 max_len = data_end - temp;
843                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
844                                                 is_unicode, nls_codepage);
845                 if (!node->node_name) {
846                         rc = -ENOMEM;
847                         goto parse_DFS_referrals_exit;
848                 }
849 
850                 node->ttl = le32_to_cpu(ref->TimeToLive);
851 
852                 ref++;
853         }
854 
855 parse_DFS_referrals_exit:
856         if (rc) {
857                 free_dfs_info_array(*target_nodes, *num_of_nodes);
858                 *target_nodes = NULL;
859                 *num_of_nodes = 0;
860         }
861         return rc;
862 }
863 
864 struct cifs_aio_ctx *
865 cifs_aio_ctx_alloc(void)
866 {
867         struct cifs_aio_ctx *ctx;
868 
869         /*
870          * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
871          * to false so that we know when we have to unreference pages within
872          * cifs_aio_ctx_release()
873          */
874         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
875         if (!ctx)
876                 return NULL;
877 
878         INIT_LIST_HEAD(&ctx->list);
879         mutex_init(&ctx->aio_mutex);
880         init_completion(&ctx->done);
881         kref_init(&ctx->refcount);
882         return ctx;
883 }
884 
885 void
886 cifs_aio_ctx_release(struct kref *refcount)
887 {
888         struct cifs_aio_ctx *ctx = container_of(refcount,
889                                         struct cifs_aio_ctx, refcount);
890 
891         cifsFileInfo_put(ctx->cfile);
892 
893         /*
894          * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
895          * which means that iov_iter_get_pages() was a success and thus that
896          * we have taken reference on pages.
897          */
898         if (ctx->bv) {
899                 unsigned i;
900 
901                 for (i = 0; i < ctx->npages; i++) {
902                         if (ctx->should_dirty)
903                                 set_page_dirty(ctx->bv[i].bv_page);
904                         put_page(ctx->bv[i].bv_page);
905                 }
906                 kvfree(ctx->bv);
907         }
908 
909         kfree(ctx);
910 }
911 
912 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
913 
914 int
915 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
916 {
917         ssize_t rc;
918         unsigned int cur_npages;
919         unsigned int npages = 0;
920         unsigned int i;
921         size_t len;
922         size_t count = iov_iter_count(iter);
923         unsigned int saved_len;
924         size_t start;
925         unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
926         struct page **pages = NULL;
927         struct bio_vec *bv = NULL;
928 
929         if (iov_iter_is_kvec(iter)) {
930                 memcpy(&ctx->iter, iter, sizeof(*iter));
931                 ctx->len = count;
932                 iov_iter_advance(iter, count);
933                 return 0;
934         }
935 
936         if (array_size(max_pages, sizeof(*bv)) <= CIFS_AIO_KMALLOC_LIMIT)
937                 bv = kmalloc_array(max_pages, sizeof(*bv), GFP_KERNEL);
938 
939         if (!bv) {
940                 bv = vmalloc(array_size(max_pages, sizeof(*bv)));
941                 if (!bv)
942                         return -ENOMEM;
943         }
944 
945         if (array_size(max_pages, sizeof(*pages)) <= CIFS_AIO_KMALLOC_LIMIT)
946                 pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
947 
948         if (!pages) {
949                 pages = vmalloc(array_size(max_pages, sizeof(*pages)));
950                 if (!pages) {
951                         kvfree(bv);
952                         return -ENOMEM;
953                 }
954         }
955 
956         saved_len = count;
957 
958         while (count && npages < max_pages) {
959                 rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
960                 if (rc < 0) {
961                         cifs_dbg(VFS, "Couldn't get user pages (rc=%zd)\n", rc);
962                         break;
963                 }
964 
965                 if (rc > count) {
966                         cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
967                                  count);
968                         break;
969                 }
970 
971                 iov_iter_advance(iter, rc);
972                 count -= rc;
973                 rc += start;
974                 cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
975 
976                 if (npages + cur_npages > max_pages) {
977                         cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
978                                  npages + cur_npages, max_pages);
979                         break;
980                 }
981 
982                 for (i = 0; i < cur_npages; i++) {
983                         len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
984                         bv[npages + i].bv_page = pages[i];
985                         bv[npages + i].bv_offset = start;
986                         bv[npages + i].bv_len = len - start;
987                         rc -= len;
988                         start = 0;
989                 }
990 
991                 npages += cur_npages;
992         }
993 
994         kvfree(pages);
995         ctx->bv = bv;
996         ctx->len = saved_len - count;
997         ctx->npages = npages;
998         iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len);
999         return 0;
1000 }
1001 
1002 /**
1003  * cifs_alloc_hash - allocate hash and hash context together
1004  *
1005  * The caller has to make sure @sdesc is initialized to either NULL or
1006  * a valid context. Both can be freed via cifs_free_hash().
1007  */
1008 int
1009 cifs_alloc_hash(const char *name,
1010                 struct crypto_shash **shash, struct sdesc **sdesc)
1011 {
1012         int rc = 0;
1013         size_t size;
1014 
1015         if (*sdesc != NULL)
1016                 return 0;
1017 
1018         *shash = crypto_alloc_shash(name, 0, 0);
1019         if (IS_ERR(*shash)) {
1020                 cifs_dbg(VFS, "Could not allocate crypto %s\n", name);
1021                 rc = PTR_ERR(*shash);
1022                 *shash = NULL;
1023                 *sdesc = NULL;
1024                 return rc;
1025         }
1026 
1027         size = sizeof(struct shash_desc) + crypto_shash_descsize(*shash);
1028         *sdesc = kmalloc(size, GFP_KERNEL);
1029         if (*sdesc == NULL) {
1030                 cifs_dbg(VFS, "no memory left to allocate crypto %s\n", name);
1031                 crypto_free_shash(*shash);
1032                 *shash = NULL;
1033                 return -ENOMEM;
1034         }
1035 
1036         (*sdesc)->shash.tfm = *shash;
1037         return 0;
1038 }
1039 
1040 /**
1041  * cifs_free_hash - free hash and hash context together
1042  *
1043  * Freeing a NULL hash or context is safe.
1044  */
1045 void
1046 cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc)
1047 {
1048         kfree(*sdesc);
1049         *sdesc = NULL;
1050         if (*shash)
1051                 crypto_free_shash(*shash);
1052         *shash = NULL;
1053 }
1054 
1055 /**
1056  * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
1057  * Input: rqst - a smb_rqst, page - a page index for rqst
1058  * Output: *len - the length for this page, *offset - the offset for this page
1059  */
1060 void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page,
1061                                 unsigned int *len, unsigned int *offset)
1062 {
1063         *len = rqst->rq_pagesz;
1064         *offset = (page == 0) ? rqst->rq_offset : 0;
1065 
1066         if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
1067                 *len = rqst->rq_tailsz;
1068         else if (page == 0)
1069                 *len = rqst->rq_pagesz - rqst->rq_offset;
1070 }
1071 
1072 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
1073 {
1074         const char *end;
1075 
1076         /* skip initial slashes */
1077         while (*unc && (*unc == '\\' || *unc == '/'))
1078                 unc++;
1079 
1080         end = unc;
1081 
1082         while (*end && !(*end == '\\' || *end == '/'))
1083                 end++;
1084 
1085         *h = unc;
1086         *len = end - unc;
1087 }
1088 
1089 /**
1090  * copy_path_name - copy src path to dst, possibly truncating
1091  *
1092  * returns number of bytes written (including trailing nul)
1093  */
1094 int copy_path_name(char *dst, const char *src)
1095 {
1096         int name_len;
1097 
1098         /*
1099          * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1100          * will truncate and strlen(dst) will be PATH_MAX-1
1101          */
1102         name_len = strscpy(dst, src, PATH_MAX);
1103         if (WARN_ON_ONCE(name_len < 0))
1104                 name_len = PATH_MAX-1;
1105 
1106         /* we count the trailing nul */
1107         name_len++;
1108         return name_len;
1109 }
1110 
1111 struct super_cb_data {
1112         void *data;
1113         struct super_block *sb;
1114 };
1115 
1116 static void tcp_super_cb(struct super_block *sb, void *arg)
1117 {
1118         struct super_cb_data *sd = arg;
1119         struct TCP_Server_Info *server = sd->data;
1120         struct cifs_sb_info *cifs_sb;
1121         struct cifs_tcon *tcon;
1122 
1123         if (sd->sb)
1124                 return;
1125 
1126         cifs_sb = CIFS_SB(sb);
1127         tcon = cifs_sb_master_tcon(cifs_sb);
1128         if (tcon->ses->server == server)
1129                 sd->sb = sb;
1130 }
1131 
1132 static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1133                                             void *data)
1134 {
1135         struct super_cb_data sd = {
1136                 .data = data,
1137                 .sb = NULL,
1138         };
1139 
1140         iterate_supers_type(&cifs_fs_type, f, &sd);
1141 
1142         if (!sd.sb)
1143                 return ERR_PTR(-EINVAL);
1144         /*
1145          * Grab an active reference in order to prevent automounts (DFS links)
1146          * of expiring and then freeing up our cifs superblock pointer while
1147          * we're doing failover.
1148          */
1149         cifs_sb_active(sd.sb);
1150         return sd.sb;
1151 }
1152 
1153 static void __cifs_put_super(struct super_block *sb)
1154 {
1155         if (!IS_ERR_OR_NULL(sb))
1156                 cifs_sb_deactive(sb);
1157 }
1158 
1159 struct super_block *cifs_get_tcp_super(struct TCP_Server_Info *server)
1160 {
1161         return __cifs_get_super(tcp_super_cb, server);
1162 }
1163 
1164 void cifs_put_tcp_super(struct super_block *sb)
1165 {
1166         __cifs_put_super(sb);
1167 }
1168 
1169 #ifdef CONFIG_CIFS_DFS_UPCALL
1170 int match_target_ip(struct TCP_Server_Info *server,
1171                     const char *share, size_t share_len,
1172                     bool *result)
1173 {
1174         int rc;
1175         char *target, *tip = NULL;
1176         struct sockaddr tipaddr;
1177 
1178         *result = false;
1179 
1180         target = kzalloc(share_len + 3, GFP_KERNEL);
1181         if (!target) {
1182                 rc = -ENOMEM;
1183                 goto out;
1184         }
1185 
1186         scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
1187 
1188         cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
1189 
1190         rc = dns_resolve_server_name_to_ip(target, &tip, NULL);
1191         if (rc < 0)
1192                 goto out;
1193 
1194         cifs_dbg(FYI, "%s: target ip: %s\n", __func__, tip);
1195 
1196         if (!cifs_convert_address(&tipaddr, tip, strlen(tip))) {
1197                 cifs_dbg(VFS, "%s: failed to convert target ip address\n",
1198                          __func__);
1199                 rc = -EINVAL;
1200                 goto out;
1201         }
1202 
1203         *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr,
1204                                     &tipaddr);
1205         cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
1206         rc = 0;
1207 
1208 out:
1209         kfree(target);
1210         kfree(tip);
1211 
1212         return rc;
1213 }
1214 
1215 static void tcon_super_cb(struct super_block *sb, void *arg)
1216 {
1217         struct super_cb_data *sd = arg;
1218         struct cifs_tcon *tcon = sd->data;
1219         struct cifs_sb_info *cifs_sb;
1220 
1221         if (sd->sb)
1222                 return;
1223 
1224         cifs_sb = CIFS_SB(sb);
1225         if (tcon->dfs_path && cifs_sb->origin_fullpath &&
1226             !strcasecmp(tcon->dfs_path, cifs_sb->origin_fullpath))
1227                 sd->sb = sb;
1228 }
1229 
1230 static inline struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon)
1231 {
1232         return __cifs_get_super(tcon_super_cb, tcon);
1233 }
1234 
1235 static inline void cifs_put_tcon_super(struct super_block *sb)
1236 {
1237         __cifs_put_super(sb);
1238 }
1239 #else
1240 static inline struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon)
1241 {
1242         return ERR_PTR(-EOPNOTSUPP);
1243 }
1244 
1245 static inline void cifs_put_tcon_super(struct super_block *sb)
1246 {
1247 }
1248 #endif
1249 
1250 int update_super_prepath(struct cifs_tcon *tcon, char *prefix)
1251 {
1252         struct super_block *sb;
1253         struct cifs_sb_info *cifs_sb;
1254         int rc = 0;
1255 
1256         sb = cifs_get_tcon_super(tcon);
1257         if (IS_ERR(sb))
1258                 return PTR_ERR(sb);
1259 
1260         cifs_sb = CIFS_SB(sb);
1261 
1262         kfree(cifs_sb->prepath);
1263 
1264         if (prefix && *prefix) {
1265                 cifs_sb->prepath = kstrdup(prefix, GFP_ATOMIC);
1266                 if (!cifs_sb->prepath) {
1267                         rc = -ENOMEM;
1268                         goto out;
1269                 }
1270 
1271                 convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1272         } else
1273                 cifs_sb->prepath = NULL;
1274 
1275         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1276 
1277 out:
1278         cifs_put_tcon_super(sb);
1279         return rc;
1280 }
1281 

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