1 /*
2 * fs/cifs/link.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 #include <linux/fs.h>
22 #include <linux/stat.h>
23 #include <linux/slab.h>
24 #include <linux/namei.h>
25 #include "cifsfs.h"
26 #include "cifspdu.h"
27 #include "cifsglob.h"
28 #include "cifsproto.h"
29 #include "cifs_debug.h"
30 #include "cifs_fs_sb.h"
31 #include "cifs_unicode.h"
32 #include "smb2proto.h"
33 #include "cifs_ioctl.h"
34
35 /*
36 * M-F Symlink Functions - Begin
37 */
38
39 #define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
40 #define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
41 #define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
42 #define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
43 #define CIFS_MF_SYMLINK_FILE_SIZE \
44 (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
45
46 #define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
47 #define CIFS_MF_SYMLINK_MD5_FORMAT "%16phN\n"
48 #define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) md5_hash
49
50 static int
symlink_hash(unsigned int link_len,const char * link_str,u8 * md5_hash)51 symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
52 {
53 int rc;
54 struct crypto_shash *md5 = NULL;
55 struct sdesc *sdescmd5 = NULL;
56
57 rc = cifs_alloc_hash("md5", &md5, &sdescmd5);
58 if (rc)
59 goto symlink_hash_err;
60
61 rc = crypto_shash_init(&sdescmd5->shash);
62 if (rc) {
63 cifs_dbg(VFS, "%s: Could not init md5 shash\n", __func__);
64 goto symlink_hash_err;
65 }
66 rc = crypto_shash_update(&sdescmd5->shash, link_str, link_len);
67 if (rc) {
68 cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
69 goto symlink_hash_err;
70 }
71 rc = crypto_shash_final(&sdescmd5->shash, md5_hash);
72 if (rc)
73 cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
74
75 symlink_hash_err:
76 cifs_free_hash(&md5, &sdescmd5);
77 return rc;
78 }
79
80 static int
parse_mf_symlink(const u8 * buf,unsigned int buf_len,unsigned int * _link_len,char ** _link_str)81 parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
82 char **_link_str)
83 {
84 int rc;
85 unsigned int link_len;
86 const char *md5_str1;
87 const char *link_str;
88 u8 md5_hash[16];
89 char md5_str2[34];
90
91 if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
92 return -EINVAL;
93
94 md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
95 link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
96
97 rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
98 if (rc != 1)
99 return -EINVAL;
100
101 rc = symlink_hash(link_len, link_str, md5_hash);
102 if (rc) {
103 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
104 return rc;
105 }
106
107 scnprintf(md5_str2, sizeof(md5_str2),
108 CIFS_MF_SYMLINK_MD5_FORMAT,
109 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
110
111 if (strncmp(md5_str1, md5_str2, 17) != 0)
112 return -EINVAL;
113
114 if (_link_str) {
115 *_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
116 if (!*_link_str)
117 return -ENOMEM;
118 }
119
120 *_link_len = link_len;
121 return 0;
122 }
123
124 static int
format_mf_symlink(u8 * buf,unsigned int buf_len,const char * link_str)125 format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
126 {
127 int rc;
128 unsigned int link_len;
129 unsigned int ofs;
130 u8 md5_hash[16];
131
132 if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
133 return -EINVAL;
134
135 link_len = strlen(link_str);
136
137 if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
138 return -ENAMETOOLONG;
139
140 rc = symlink_hash(link_len, link_str, md5_hash);
141 if (rc) {
142 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
143 return rc;
144 }
145
146 scnprintf(buf, buf_len,
147 CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
148 link_len,
149 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
150
151 ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
152 memcpy(buf + ofs, link_str, link_len);
153
154 ofs += link_len;
155 if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
156 buf[ofs] = '\n';
157 ofs++;
158 }
159
160 while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
161 buf[ofs] = ' ';
162 ofs++;
163 }
164
165 return 0;
166 }
167
168 bool
couldbe_mf_symlink(const struct cifs_fattr * fattr)169 couldbe_mf_symlink(const struct cifs_fattr *fattr)
170 {
171 if (!S_ISREG(fattr->cf_mode))
172 /* it's not a symlink */
173 return false;
174
175 if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
176 /* it's not a symlink */
177 return false;
178
179 return true;
180 }
181
182 static int
create_mf_symlink(const unsigned int xid,struct cifs_tcon * tcon,struct cifs_sb_info * cifs_sb,const char * fromName,const char * toName)183 create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
184 struct cifs_sb_info *cifs_sb, const char *fromName,
185 const char *toName)
186 {
187 int rc;
188 u8 *buf;
189 unsigned int bytes_written = 0;
190
191 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
192 if (!buf)
193 return -ENOMEM;
194
195 rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
196 if (rc)
197 goto out;
198
199 if (tcon->ses->server->ops->create_mf_symlink)
200 rc = tcon->ses->server->ops->create_mf_symlink(xid, tcon,
201 cifs_sb, fromName, buf, &bytes_written);
202 else
203 rc = -EOPNOTSUPP;
204
205 if (rc)
206 goto out;
207
208 if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
209 rc = -EIO;
210 out:
211 kfree(buf);
212 return rc;
213 }
214
215 static int
query_mf_symlink(const unsigned int xid,struct cifs_tcon * tcon,struct cifs_sb_info * cifs_sb,const unsigned char * path,char ** symlinkinfo)216 query_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
217 struct cifs_sb_info *cifs_sb, const unsigned char *path,
218 char **symlinkinfo)
219 {
220 int rc;
221 u8 *buf = NULL;
222 unsigned int link_len = 0;
223 unsigned int bytes_read = 0;
224
225 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
226 if (!buf)
227 return -ENOMEM;
228
229 if (tcon->ses->server->ops->query_mf_symlink)
230 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
231 cifs_sb, path, buf, &bytes_read);
232 else
233 rc = -ENOSYS;
234
235 if (rc)
236 goto out;
237
238 if (bytes_read == 0) { /* not a symlink */
239 rc = -EINVAL;
240 goto out;
241 }
242
243 rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo);
244 out:
245 kfree(buf);
246 return rc;
247 }
248
249 int
check_mf_symlink(unsigned int xid,struct cifs_tcon * tcon,struct cifs_sb_info * cifs_sb,struct cifs_fattr * fattr,const unsigned char * path)250 check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
251 struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
252 const unsigned char *path)
253 {
254 int rc;
255 u8 *buf = NULL;
256 unsigned int link_len = 0;
257 unsigned int bytes_read = 0;
258
259 if (!couldbe_mf_symlink(fattr))
260 /* it's not a symlink */
261 return 0;
262
263 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
264 if (!buf)
265 return -ENOMEM;
266
267 if (tcon->ses->server->ops->query_mf_symlink)
268 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
269 cifs_sb, path, buf, &bytes_read);
270 else
271 rc = -ENOSYS;
272
273 if (rc)
274 goto out;
275
276 if (bytes_read == 0) /* not a symlink */
277 goto out;
278
279 rc = parse_mf_symlink(buf, bytes_read, &link_len, NULL);
280 if (rc == -EINVAL) {
281 /* it's not a symlink */
282 rc = 0;
283 goto out;
284 }
285
286 if (rc != 0)
287 goto out;
288
289 /* it is a symlink */
290 fattr->cf_eof = link_len;
291 fattr->cf_mode &= ~S_IFMT;
292 fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
293 fattr->cf_dtype = DT_LNK;
294 out:
295 kfree(buf);
296 return rc;
297 }
298
299 /*
300 * SMB 1.0 Protocol specific functions
301 */
302
303 int
cifs_query_mf_symlink(unsigned int xid,struct cifs_tcon * tcon,struct cifs_sb_info * cifs_sb,const unsigned char * path,char * pbuf,unsigned int * pbytes_read)304 cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
305 struct cifs_sb_info *cifs_sb, const unsigned char *path,
306 char *pbuf, unsigned int *pbytes_read)
307 {
308 int rc;
309 int oplock = 0;
310 struct cifs_fid fid;
311 struct cifs_open_parms oparms;
312 struct cifs_io_parms io_parms = {0};
313 int buf_type = CIFS_NO_BUFFER;
314 FILE_ALL_INFO file_info;
315
316 oparms.tcon = tcon;
317 oparms.cifs_sb = cifs_sb;
318 oparms.desired_access = GENERIC_READ;
319 oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR);
320 oparms.disposition = FILE_OPEN;
321 oparms.path = path;
322 oparms.fid = &fid;
323 oparms.reconnect = false;
324
325 rc = CIFS_open(xid, &oparms, &oplock, &file_info);
326 if (rc)
327 return rc;
328
329 if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
330 rc = -ENOENT;
331 /* it's not a symlink */
332 goto out;
333 }
334
335 io_parms.netfid = fid.netfid;
336 io_parms.pid = current->tgid;
337 io_parms.tcon = tcon;
338 io_parms.offset = 0;
339 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
340
341 rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
342 out:
343 CIFSSMBClose(xid, tcon, fid.netfid);
344 return rc;
345 }
346
347 int
cifs_create_mf_symlink(unsigned int xid,struct cifs_tcon * tcon,struct cifs_sb_info * cifs_sb,const unsigned char * path,char * pbuf,unsigned int * pbytes_written)348 cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
349 struct cifs_sb_info *cifs_sb, const unsigned char *path,
350 char *pbuf, unsigned int *pbytes_written)
351 {
352 int rc;
353 int oplock = 0;
354 struct cifs_fid fid;
355 struct cifs_open_parms oparms;
356 struct cifs_io_parms io_parms = {0};
357
358 oparms.tcon = tcon;
359 oparms.cifs_sb = cifs_sb;
360 oparms.desired_access = GENERIC_WRITE;
361 oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR);
362 oparms.disposition = FILE_CREATE;
363 oparms.path = path;
364 oparms.fid = &fid;
365 oparms.reconnect = false;
366
367 rc = CIFS_open(xid, &oparms, &oplock, NULL);
368 if (rc)
369 return rc;
370
371 io_parms.netfid = fid.netfid;
372 io_parms.pid = current->tgid;
373 io_parms.tcon = tcon;
374 io_parms.offset = 0;
375 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
376
377 rc = CIFSSMBWrite(xid, &io_parms, pbytes_written, pbuf);
378 CIFSSMBClose(xid, tcon, fid.netfid);
379 return rc;
380 }
381
382 /*
383 * SMB 2.1/SMB3 Protocol specific functions
384 */
385 int
smb3_query_mf_symlink(unsigned int xid,struct cifs_tcon * tcon,struct cifs_sb_info * cifs_sb,const unsigned char * path,char * pbuf,unsigned int * pbytes_read)386 smb3_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
387 struct cifs_sb_info *cifs_sb, const unsigned char *path,
388 char *pbuf, unsigned int *pbytes_read)
389 {
390 int rc;
391 struct cifs_fid fid;
392 struct cifs_open_parms oparms;
393 struct cifs_io_parms io_parms = {0};
394 int buf_type = CIFS_NO_BUFFER;
395 __le16 *utf16_path;
396 __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
397 struct smb2_file_all_info *pfile_info = NULL;
398
399 oparms.tcon = tcon;
400 oparms.cifs_sb = cifs_sb;
401 oparms.desired_access = GENERIC_READ;
402 oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR);
403 oparms.disposition = FILE_OPEN;
404 oparms.fid = &fid;
405 oparms.reconnect = false;
406
407 utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
408 if (utf16_path == NULL)
409 return -ENOMEM;
410
411 pfile_info = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2,
412 GFP_KERNEL);
413
414 if (pfile_info == NULL) {
415 kfree(utf16_path);
416 return -ENOMEM;
417 }
418
419 rc = SMB2_open(xid, &oparms, utf16_path, &oplock, pfile_info, NULL,
420 NULL, NULL);
421 if (rc)
422 goto qmf_out_open_fail;
423
424 if (pfile_info->EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
425 /* it's not a symlink */
426 rc = -ENOENT; /* Is there a better rc to return? */
427 goto qmf_out;
428 }
429
430 io_parms.netfid = fid.netfid;
431 io_parms.pid = current->tgid;
432 io_parms.tcon = tcon;
433 io_parms.offset = 0;
434 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
435 io_parms.persistent_fid = fid.persistent_fid;
436 io_parms.volatile_fid = fid.volatile_fid;
437 rc = SMB2_read(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
438 qmf_out:
439 SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
440 qmf_out_open_fail:
441 kfree(utf16_path);
442 kfree(pfile_info);
443 return rc;
444 }
445
446 int
smb3_create_mf_symlink(unsigned int xid,struct cifs_tcon * tcon,struct cifs_sb_info * cifs_sb,const unsigned char * path,char * pbuf,unsigned int * pbytes_written)447 smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
448 struct cifs_sb_info *cifs_sb, const unsigned char *path,
449 char *pbuf, unsigned int *pbytes_written)
450 {
451 int rc;
452 struct cifs_fid fid;
453 struct cifs_open_parms oparms;
454 struct cifs_io_parms io_parms = {0};
455 __le16 *utf16_path;
456 __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
457 struct kvec iov[2];
458
459 cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
460
461 utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
462 if (!utf16_path)
463 return -ENOMEM;
464
465 oparms.tcon = tcon;
466 oparms.cifs_sb = cifs_sb;
467 oparms.desired_access = GENERIC_WRITE;
468 oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR);
469 oparms.disposition = FILE_CREATE;
470 oparms.fid = &fid;
471 oparms.reconnect = false;
472
473 rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL,
474 NULL, NULL);
475 if (rc) {
476 kfree(utf16_path);
477 return rc;
478 }
479
480 io_parms.netfid = fid.netfid;
481 io_parms.pid = current->tgid;
482 io_parms.tcon = tcon;
483 io_parms.offset = 0;
484 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
485 io_parms.persistent_fid = fid.persistent_fid;
486 io_parms.volatile_fid = fid.volatile_fid;
487
488 /* iov[0] is reserved for smb header */
489 iov[1].iov_base = pbuf;
490 iov[1].iov_len = CIFS_MF_SYMLINK_FILE_SIZE;
491
492 rc = SMB2_write(xid, &io_parms, pbytes_written, iov, 1);
493
494 /* Make sure we wrote all of the symlink data */
495 if ((rc == 0) && (*pbytes_written != CIFS_MF_SYMLINK_FILE_SIZE))
496 rc = -EIO;
497
498 SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
499
500 kfree(utf16_path);
501 return rc;
502 }
503
504 /*
505 * M-F Symlink Functions - End
506 */
507
508 int
cifs_hardlink(struct dentry * old_file,struct inode * inode,struct dentry * direntry)509 cifs_hardlink(struct dentry *old_file, struct inode *inode,
510 struct dentry *direntry)
511 {
512 int rc = -EACCES;
513 unsigned int xid;
514 const char *from_name, *to_name;
515 void *page1, *page2;
516 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
517 struct tcon_link *tlink;
518 struct cifs_tcon *tcon;
519 struct TCP_Server_Info *server;
520 struct cifsInodeInfo *cifsInode;
521
522 if (unlikely(cifs_forced_shutdown(cifs_sb)))
523 return -EIO;
524
525 tlink = cifs_sb_tlink(cifs_sb);
526 if (IS_ERR(tlink))
527 return PTR_ERR(tlink);
528 tcon = tlink_tcon(tlink);
529
530 xid = get_xid();
531 page1 = alloc_dentry_path();
532 page2 = alloc_dentry_path();
533
534 from_name = build_path_from_dentry(old_file, page1);
535 if (IS_ERR(from_name)) {
536 rc = PTR_ERR(from_name);
537 goto cifs_hl_exit;
538 }
539 to_name = build_path_from_dentry(direntry, page2);
540 if (IS_ERR(to_name)) {
541 rc = PTR_ERR(to_name);
542 goto cifs_hl_exit;
543 }
544
545 if (tcon->unix_ext)
546 rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
547 cifs_sb->local_nls,
548 cifs_remap(cifs_sb));
549 else {
550 server = tcon->ses->server;
551 if (!server->ops->create_hardlink) {
552 rc = -ENOSYS;
553 goto cifs_hl_exit;
554 }
555 rc = server->ops->create_hardlink(xid, tcon, from_name, to_name,
556 cifs_sb);
557 if ((rc == -EIO) || (rc == -EINVAL))
558 rc = -EOPNOTSUPP;
559 }
560
561 d_drop(direntry); /* force new lookup from server of target */
562
563 /*
564 * if source file is cached (oplocked) revalidate will not go to server
565 * until the file is closed or oplock broken so update nlinks locally
566 */
567 if (d_really_is_positive(old_file)) {
568 cifsInode = CIFS_I(d_inode(old_file));
569 if (rc == 0) {
570 spin_lock(&d_inode(old_file)->i_lock);
571 inc_nlink(d_inode(old_file));
572 spin_unlock(&d_inode(old_file)->i_lock);
573
574 /*
575 * parent dir timestamps will update from srv within a
576 * second, would it really be worth it to set the parent
577 * dir cifs inode time to zero to force revalidate
578 * (faster) for it too?
579 */
580 }
581 /*
582 * if not oplocked will force revalidate to get info on source
583 * file from srv. Note Samba server prior to 4.2 has bug -
584 * not updating src file ctime on hardlinks but Windows servers
585 * handle it properly
586 */
587 cifsInode->time = 0;
588
589 /*
590 * Will update parent dir timestamps from srv within a second.
591 * Would it really be worth it to set the parent dir (cifs
592 * inode) time field to zero to force revalidate on parent
593 * directory faster ie
594 *
595 * CIFS_I(inode)->time = 0;
596 */
597 }
598
599 cifs_hl_exit:
600 free_dentry_path(page1);
601 free_dentry_path(page2);
602 free_xid(xid);
603 cifs_put_tlink(tlink);
604 return rc;
605 }
606
607 const char *
cifs_get_link(struct dentry * direntry,struct inode * inode,struct delayed_call * done)608 cifs_get_link(struct dentry *direntry, struct inode *inode,
609 struct delayed_call *done)
610 {
611 int rc = -ENOMEM;
612 unsigned int xid;
613 const char *full_path;
614 void *page;
615 char *target_path = NULL;
616 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
617 struct tcon_link *tlink = NULL;
618 struct cifs_tcon *tcon;
619 struct TCP_Server_Info *server;
620
621 if (!direntry)
622 return ERR_PTR(-ECHILD);
623
624 xid = get_xid();
625
626 tlink = cifs_sb_tlink(cifs_sb);
627 if (IS_ERR(tlink)) {
628 free_xid(xid);
629 return ERR_CAST(tlink);
630 }
631 tcon = tlink_tcon(tlink);
632 server = tcon->ses->server;
633
634 page = alloc_dentry_path();
635 full_path = build_path_from_dentry(direntry, page);
636 if (IS_ERR(full_path)) {
637 free_xid(xid);
638 cifs_put_tlink(tlink);
639 free_dentry_path(page);
640 return ERR_CAST(full_path);
641 }
642
643 cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode);
644
645 rc = -EACCES;
646 /*
647 * First try Minshall+French Symlinks, if configured
648 * and fallback to UNIX Extensions Symlinks.
649 */
650 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
651 rc = query_mf_symlink(xid, tcon, cifs_sb, full_path,
652 &target_path);
653
654 if (rc != 0 && server->ops->query_symlink) {
655 struct cifsInodeInfo *cifsi = CIFS_I(inode);
656 bool reparse_point = false;
657
658 if (cifsi->cifsAttrs & ATTR_REPARSE)
659 reparse_point = true;
660
661 rc = server->ops->query_symlink(xid, tcon, cifs_sb, full_path,
662 &target_path, reparse_point);
663 }
664
665 free_dentry_path(page);
666 free_xid(xid);
667 cifs_put_tlink(tlink);
668 if (rc != 0) {
669 kfree(target_path);
670 return ERR_PTR(rc);
671 }
672 set_delayed_call(done, kfree_link, target_path);
673 return target_path;
674 }
675
676 int
cifs_symlink(struct user_namespace * mnt_userns,struct inode * inode,struct dentry * direntry,const char * symname)677 cifs_symlink(struct user_namespace *mnt_userns, struct inode *inode,
678 struct dentry *direntry, const char *symname)
679 {
680 int rc = -EOPNOTSUPP;
681 unsigned int xid;
682 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
683 struct tcon_link *tlink;
684 struct cifs_tcon *pTcon;
685 const char *full_path;
686 void *page;
687 struct inode *newinode = NULL;
688
689 if (unlikely(cifs_forced_shutdown(cifs_sb)))
690 return -EIO;
691
692 page = alloc_dentry_path();
693 if (!page)
694 return -ENOMEM;
695
696 xid = get_xid();
697
698 tlink = cifs_sb_tlink(cifs_sb);
699 if (IS_ERR(tlink)) {
700 rc = PTR_ERR(tlink);
701 goto symlink_exit;
702 }
703 pTcon = tlink_tcon(tlink);
704
705 full_path = build_path_from_dentry(direntry, page);
706 if (IS_ERR(full_path)) {
707 rc = PTR_ERR(full_path);
708 goto symlink_exit;
709 }
710
711 cifs_dbg(FYI, "Full path: %s\n", full_path);
712 cifs_dbg(FYI, "symname is %s\n", symname);
713
714 /* BB what if DFS and this volume is on different share? BB */
715 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
716 rc = create_mf_symlink(xid, pTcon, cifs_sb, full_path, symname);
717 else if (pTcon->unix_ext)
718 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
719 cifs_sb->local_nls,
720 cifs_remap(cifs_sb));
721 /* else
722 rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
723 cifs_sb_target->local_nls); */
724
725 if (rc == 0) {
726 if (pTcon->posix_extensions)
727 rc = smb311_posix_get_inode_info(&newinode, full_path, inode->i_sb, xid);
728 else if (pTcon->unix_ext)
729 rc = cifs_get_inode_info_unix(&newinode, full_path,
730 inode->i_sb, xid);
731 else
732 rc = cifs_get_inode_info(&newinode, full_path, NULL,
733 inode->i_sb, xid, NULL);
734
735 if (rc != 0) {
736 cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
737 rc);
738 } else {
739 d_instantiate(direntry, newinode);
740 }
741 }
742 symlink_exit:
743 free_dentry_path(page);
744 cifs_put_tlink(tlink);
745 free_xid(xid);
746 return rc;
747 }
748