fs/cifs/link.c

   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
  34 /*
  35  * M-F Symlink Functions - Begin
  36  */
  37
  38 #define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
  39 #define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
  40 #define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
  41 #define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
  42 #define CIFS_MF_SYMLINK_FILE_SIZE \
  43         (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
  44
  45 #define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
  46 #define CIFS_MF_SYMLINK_MD5_FORMAT "%16phN\n"
  47 #define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) md5_hash
  48
  49 static int
  50 symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
  51 {
  52         int rc;
  53         unsigned int size;
  54         struct crypto_shash *md5;
  55         struct sdesc *sdescmd5;
  56
  57         md5 = crypto_alloc_shash("md5", 0, 0);
  58         if (IS_ERR(md5)) {
  59                 rc = PTR_ERR(md5);
  60                 cifs_dbg(VFS, "%s: Crypto md5 allocation error %d\n",
  61                          __func__, rc);
  62                 return rc;
  63         }
  64         size = sizeof(struct shash_desc) + crypto_shash_descsize(md5);
  65         sdescmd5 = kmalloc(size, GFP_KERNEL);
  66         if (!sdescmd5) {
  67                 rc = -ENOMEM;
  68                 goto symlink_hash_err;
  69         }
  70         sdescmd5->shash.tfm = md5;
  71         sdescmd5->shash.flags = 0x0;
  72
  73         rc = crypto_shash_init(&sdescmd5->shash);
  74         if (rc) {
  75                 cifs_dbg(VFS, "%s: Could not init md5 shash\n", __func__);
  76                 goto symlink_hash_err;
  77         }
  78         rc = crypto_shash_update(&sdescmd5->shash, link_str, link_len);
  79         if (rc) {
  80                 cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
  81                 goto symlink_hash_err;
  82         }
  83         rc = crypto_shash_final(&sdescmd5->shash, md5_hash);
  84         if (rc)
  85                 cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
  86
  87 symlink_hash_err:
  88         crypto_free_shash(md5);
  89         kfree(sdescmd5);
  90
  91         return rc;
  92 }
  93
  94 static int
  95 parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
  96                  char **_link_str)
  97 {
  98         int rc;
  99         unsigned int link_len;
 100         const char *md5_str1;
 101         const char *link_str;
 102         u8 md5_hash[16];
 103         char md5_str2[34];
 104
 105         if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
 106                 return -EINVAL;
 107
 108         md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
 109         link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
 110
 111         rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
 112         if (rc != 1)
 113                 return -EINVAL;
 114
 115         rc = symlink_hash(link_len, link_str, md5_hash);
 116         if (rc) {
 117                 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
 118                 return rc;
 119         }
 120
 121         snprintf(md5_str2, sizeof(md5_str2),
 122                  CIFS_MF_SYMLINK_MD5_FORMAT,
 123                  CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
 124
 125         if (strncmp(md5_str1, md5_str2, 17) != 0)
 126                 return -EINVAL;
 127
 128         if (_link_str) {
 129                 *_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
 130                 if (!*_link_str)
 131                         return -ENOMEM;
 132         }
 133
 134         *_link_len = link_len;
 135         return 0;
 136 }
 137
 138 static int
 139 format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
 140 {
 141         int rc;
 142         unsigned int link_len;
 143         unsigned int ofs;
 144         u8 md5_hash[16];
 145
 146         if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
 147                 return -EINVAL;
 148
 149         link_len = strlen(link_str);
 150
 151         if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
 152                 return -ENAMETOOLONG;
 153
 154         rc = symlink_hash(link_len, link_str, md5_hash);
 155         if (rc) {
 156                 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
 157                 return rc;
 158         }
 159
 160         snprintf(buf, buf_len,
 161                  CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
 162                  link_len,
 163                  CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
 164
 165         ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
 166         memcpy(buf + ofs, link_str, link_len);
 167
 168         ofs += link_len;
 169         if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
 170                 buf[ofs] = '\n';
 171                 ofs++;
 172         }
 173
 174         while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
 175                 buf[ofs] = ' ';
 176                 ofs++;
 177         }
 178
 179         return 0;
 180 }
 181
 182 bool
 183 couldbe_mf_symlink(const struct cifs_fattr *fattr)
 184 {
 185         if (!S_ISREG(fattr->cf_mode))
 186                 /* it's not a symlink */
 187                 return false;
 188
 189         if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
 190                 /* it's not a symlink */
 191                 return false;
 192
 193         return true;
 194 }
 195
 196 static int
 197 create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 198                   struct cifs_sb_info *cifs_sb, const char *fromName,
 199                   const char *toName)
 200 {
 201         int rc;
 202         u8 *buf;
 203         unsigned int bytes_written = 0;
 204
 205         buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
 206         if (!buf)
 207                 return -ENOMEM;
 208
 209         rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
 210         if (rc)
 211                 goto out;
 212
 213         if (tcon->ses->server->ops->create_mf_symlink)
 214                 rc = tcon->ses->server->ops->create_mf_symlink(xid, tcon,
 215                                         cifs_sb, fromName, buf, &bytes_written);
 216         else
 217                 rc = -EOPNOTSUPP;
 218
 219         if (rc)
 220                 goto out;
 221
 222         if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
 223                 rc = -EIO;
 224 out:
 225         kfree(buf);
 226         return rc;
 227 }
 228
 229 static int
 230 query_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 231                  struct cifs_sb_info *cifs_sb, const unsigned char *path,
 232                  char **symlinkinfo)
 233 {
 234         int rc;
 235         u8 *buf = NULL;
 236         unsigned int link_len = 0;
 237         unsigned int bytes_read = 0;
 238
 239         buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
 240         if (!buf)
 241                 return -ENOMEM;
 242
 243         if (tcon->ses->server->ops->query_mf_symlink)
 244                 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
 245                                               cifs_sb, path, buf, &bytes_read);
 246         else
 247                 rc = -ENOSYS;
 248
 249         if (rc)
 250                 goto out;
 251
 252         if (bytes_read == 0) { /* not a symlink */
 253                 rc = -EINVAL;
 254                 goto out;
 255         }
 256
 257         rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo);
 258 out:
 259         kfree(buf);
 260         return rc;
 261 }
 262
 263 int
 264 check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 265                  struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
 266                  const unsigned char *path)
 267 {
 268         int rc;
 269         u8 *buf = NULL;
 270         unsigned int link_len = 0;
 271         unsigned int bytes_read = 0;
 272
 273         if (!couldbe_mf_symlink(fattr))
 274                 /* it's not a symlink */
 275                 return 0;
 276
 277         buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
 278         if (!buf)
 279                 return -ENOMEM;
 280
 281         if (tcon->ses->server->ops->query_mf_symlink)
 282                 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
 283                                               cifs_sb, path, buf, &bytes_read);
 284         else
 285                 rc = -ENOSYS;
 286
 287         if (rc)
 288                 goto out;
 289
 290         if (bytes_read == 0) /* not a symlink */
 291                 goto out;
 292
 293         rc = parse_mf_symlink(buf, bytes_read, &link_len, NULL);
 294         if (rc == -EINVAL) {
 295                 /* it's not a symlink */
 296                 rc = 0;
 297                 goto out;
 298         }
 299
 300         if (rc != 0)
 301                 goto out;
 302
 303         /* it is a symlink */
 304         fattr->cf_eof = link_len;
 305         fattr->cf_mode &= ~S_IFMT;
 306         fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
 307         fattr->cf_dtype = DT_LNK;
 308 out:
 309         kfree(buf);
 310         return rc;
 311 }
 312
 313 /*
 314  * SMB 1.0 Protocol specific functions
 315  */
 316
 317 int
 318 cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 319                       struct cifs_sb_info *cifs_sb, const unsigned char *path,
 320                       char *pbuf, unsigned int *pbytes_read)
 321 {
 322         int rc;
 323         int oplock = 0;
 324         struct cifs_fid fid;
 325         struct cifs_open_parms oparms;
 326         struct cifs_io_parms io_parms;
 327         int buf_type = CIFS_NO_BUFFER;
 328         FILE_ALL_INFO file_info;
 329
 330         oparms.tcon = tcon;
 331         oparms.cifs_sb = cifs_sb;
 332         oparms.desired_access = GENERIC_READ;
 333         oparms.create_options = CREATE_NOT_DIR;
 334         oparms.disposition = FILE_OPEN;
 335         oparms.path = path;
 336         oparms.fid = &fid;
 337         oparms.reconnect = false;
 338
 339         rc = CIFS_open(xid, &oparms, &oplock, &file_info);
 340         if (rc)
 341                 return rc;
 342
 343         if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
 344                 rc = -ENOENT;
 345                 /* it's not a symlink */
 346                 goto out;
 347         }
 348
 349         io_parms.netfid = fid.netfid;
 350         io_parms.pid = current->tgid;
 351         io_parms.tcon = tcon;
 352         io_parms.offset = 0;
 353         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
 354
 355         rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
 356 out:
 357         CIFSSMBClose(xid, tcon, fid.netfid);
 358         return rc;
 359 }
 360
 361 int
 362 cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 363                        struct cifs_sb_info *cifs_sb, const unsigned char *path,
 364                        char *pbuf, unsigned int *pbytes_written)
 365 {
 366         int rc;
 367         int oplock = 0;
 368         struct cifs_fid fid;
 369         struct cifs_open_parms oparms;
 370         struct cifs_io_parms io_parms;
 371         int create_options = CREATE_NOT_DIR;
 372
 373         if (backup_cred(cifs_sb))
 374                 create_options |= CREATE_OPEN_BACKUP_INTENT;
 375
 376         oparms.tcon = tcon;
 377         oparms.cifs_sb = cifs_sb;
 378         oparms.desired_access = GENERIC_WRITE;
 379         oparms.create_options = create_options;
 380         oparms.disposition = FILE_CREATE;
 381         oparms.path = path;
 382         oparms.fid = &fid;
 383         oparms.reconnect = false;
 384
 385         rc = CIFS_open(xid, &oparms, &oplock, NULL);
 386         if (rc)
 387                 return rc;
 388
 389         io_parms.netfid = fid.netfid;
 390         io_parms.pid = current->tgid;
 391         io_parms.tcon = tcon;
 392         io_parms.offset = 0;
 393         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
 394
 395         rc = CIFSSMBWrite(xid, &io_parms, pbytes_written, pbuf);
 396         CIFSSMBClose(xid, tcon, fid.netfid);
 397         return rc;
 398 }
 399
 400 /*
 401  * SMB 2.1/SMB3 Protocol specific functions
 402  */
 403 int
 404 smb3_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 405                       struct cifs_sb_info *cifs_sb, const unsigned char *path,
 406                       char *pbuf, unsigned int *pbytes_read)
 407 {
 408         int rc;
 409         struct cifs_fid fid;
 410         struct cifs_open_parms oparms;
 411         struct cifs_io_parms io_parms;
 412         int buf_type = CIFS_NO_BUFFER;
 413         __le16 *utf16_path;
 414         __u8 oplock = SMB2_OPLOCK_LEVEL_II;
 415         struct smb2_file_all_info *pfile_info = NULL;
 416
 417         oparms.tcon = tcon;
 418         oparms.cifs_sb = cifs_sb;
 419         oparms.desired_access = GENERIC_READ;
 420         oparms.create_options = CREATE_NOT_DIR;
 421         if (backup_cred(cifs_sb))
 422                 oparms.create_options |= CREATE_OPEN_BACKUP_INTENT;
 423         oparms.disposition = FILE_OPEN;
 424         oparms.fid = &fid;
 425         oparms.reconnect = false;
 426
 427         utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 428         if (utf16_path == NULL)
 429                 return -ENOMEM;
 430
 431         pfile_info = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2,
 432                              GFP_KERNEL);
 433
 434         if (pfile_info == NULL) {
 435                 kfree(utf16_path);
 436                 return  -ENOMEM;
 437         }
 438
 439         rc = SMB2_open(xid, &oparms, utf16_path, &oplock, pfile_info, NULL);
 440         if (rc)
 441                 goto qmf_out_open_fail;
 442
 443         if (pfile_info->EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
 444                 /* it's not a symlink */
 445                 rc = -ENOENT; /* Is there a better rc to return? */
 446                 goto qmf_out;
 447         }
 448
 449         io_parms.netfid = fid.netfid;
 450         io_parms.pid = current->tgid;
 451         io_parms.tcon = tcon;
 452         io_parms.offset = 0;
 453         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
 454         io_parms.persistent_fid = fid.persistent_fid;
 455         io_parms.volatile_fid = fid.volatile_fid;
 456         rc = SMB2_read(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
 457 qmf_out:
 458         SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
 459 qmf_out_open_fail:
 460         kfree(utf16_path);
 461         kfree(pfile_info);
 462         return rc;
 463 }
 464
 465 int
 466 smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 467                        struct cifs_sb_info *cifs_sb, const unsigned char *path,
 468                        char *pbuf, unsigned int *pbytes_written)
 469 {
 470         int rc;
 471         struct cifs_fid fid;
 472         struct cifs_open_parms oparms;
 473         struct cifs_io_parms io_parms;
 474         int create_options = CREATE_NOT_DIR;
 475         __le16 *utf16_path;
 476         __u8 oplock = SMB2_OPLOCK_LEVEL_EXCLUSIVE;
 477         struct kvec iov[2];
 478
 479         if (backup_cred(cifs_sb))
 480                 create_options |= CREATE_OPEN_BACKUP_INTENT;
 481
 482         cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
 483
 484         utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 485         if (!utf16_path)
 486                 return -ENOMEM;
 487
 488         oparms.tcon = tcon;
 489         oparms.cifs_sb = cifs_sb;
 490         oparms.desired_access = GENERIC_WRITE;
 491         oparms.create_options = create_options;
 492         oparms.disposition = FILE_CREATE;
 493         oparms.fid = &fid;
 494         oparms.reconnect = false;
 495
 496         rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL);
 497         if (rc) {
 498                 kfree(utf16_path);
 499                 return rc;
 500         }
 501
 502         io_parms.netfid = fid.netfid;
 503         io_parms.pid = current->tgid;
 504         io_parms.tcon = tcon;
 505         io_parms.offset = 0;
 506         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
 507         io_parms.persistent_fid = fid.persistent_fid;
 508         io_parms.volatile_fid = fid.volatile_fid;
 509
 510         /* iov[0] is reserved for smb header */
 511         iov[1].iov_base = pbuf;
 512         iov[1].iov_len = CIFS_MF_SYMLINK_FILE_SIZE;
 513
 514         rc = SMB2_write(xid, &io_parms, pbytes_written, iov, 1);
 515
 516         /* Make sure we wrote all of the symlink data */
 517         if ((rc == 0) && (*pbytes_written != CIFS_MF_SYMLINK_FILE_SIZE))
 518                 rc = -EIO;
 519
 520         SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
 521
 522         kfree(utf16_path);
 523         return rc;
 524 }
 525
 526 /*
 527  * M-F Symlink Functions - End
 528  */
 529
 530 int
 531 cifs_hardlink(struct dentry *old_file, struct inode *inode,
 532               struct dentry *direntry)
 533 {
 534         int rc = -EACCES;
 535         unsigned int xid;
 536         char *from_name = NULL;
 537         char *to_name = NULL;
 538         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 539         struct tcon_link *tlink;
 540         struct cifs_tcon *tcon;
 541         struct TCP_Server_Info *server;
 542         struct cifsInodeInfo *cifsInode;
 543
 544         tlink = cifs_sb_tlink(cifs_sb);
 545         if (IS_ERR(tlink))
 546                 return PTR_ERR(tlink);
 547         tcon = tlink_tcon(tlink);
 548
 549         xid = get_xid();
 550
 551         from_name = build_path_from_dentry(old_file);
 552         to_name = build_path_from_dentry(direntry);
 553         if ((from_name == NULL) || (to_name == NULL)) {
 554                 rc = -ENOMEM;
 555                 goto cifs_hl_exit;
 556         }
 557
 558         if (tcon->unix_ext)
 559                 rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
 560                                             cifs_sb->local_nls,
 561                                             cifs_remap(cifs_sb));
 562         else {
 563                 server = tcon->ses->server;
 564                 if (!server->ops->create_hardlink) {
 565                         rc = -ENOSYS;
 566                         goto cifs_hl_exit;
 567                 }
 568                 rc = server->ops->create_hardlink(xid, tcon, from_name, to_name,
 569                                                   cifs_sb);
 570                 if ((rc == -EIO) || (rc == -EINVAL))
 571                         rc = -EOPNOTSUPP;
 572         }
 573
 574         d_drop(direntry);       /* force new lookup from server of target */
 575
 576         /*
 577          * if source file is cached (oplocked) revalidate will not go to server
 578          * until the file is closed or oplock broken so update nlinks locally
 579          */
 580         if (d_really_is_positive(old_file)) {
 581                 cifsInode = CIFS_I(d_inode(old_file));
 582                 if (rc == 0) {
 583                         spin_lock(&d_inode(old_file)->i_lock);
 584                         inc_nlink(d_inode(old_file));
 585                         spin_unlock(&d_inode(old_file)->i_lock);
 586
 587                         /*
 588                          * parent dir timestamps will update from srv within a
 589                          * second, would it really be worth it to set the parent
 590                          * dir cifs inode time to zero to force revalidate
 591                          * (faster) for it too?
 592                          */
 593                 }
 594                 /*
 595                  * if not oplocked will force revalidate to get info on source
 596                  * file from srv.  Note Samba server prior to 4.2 has bug -
 597                  * not updating src file ctime on hardlinks but Windows servers
 598                  * handle it properly
 599                  */
 600                 cifsInode->time = 0;
 601
 602                 /*
 603                  * Will update parent dir timestamps from srv within a second.
 604                  * Would it really be worth it to set the parent dir (cifs
 605                  * inode) time field to zero to force revalidate on parent
 606                  * directory faster ie
 607                  *
 608                  * CIFS_I(inode)->time = 0;
 609                  */
 610         }
 611
 612 cifs_hl_exit:
 613         kfree(from_name);
 614         kfree(to_name);
 615         free_xid(xid);
 616         cifs_put_tlink(tlink);
 617         return rc;
 618 }
 619
 620 const char *
 621 cifs_get_link(struct dentry *direntry, struct inode *inode,
 622               struct delayed_call *done)
 623 {
 624         int rc = -ENOMEM;
 625         unsigned int xid;
 626         char *full_path = NULL;
 627         char *target_path = NULL;
 628         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 629         struct tcon_link *tlink = NULL;
 630         struct cifs_tcon *tcon;
 631         struct TCP_Server_Info *server;
 632
 633         if (!direntry)
 634                 return ERR_PTR(-ECHILD);
 635
 636         xid = get_xid();
 637
 638         tlink = cifs_sb_tlink(cifs_sb);
 639         if (IS_ERR(tlink)) {
 640                 free_xid(xid);
 641                 return ERR_CAST(tlink);
 642         }
 643         tcon = tlink_tcon(tlink);
 644         server = tcon->ses->server;
 645
 646         full_path = build_path_from_dentry(direntry);
 647         if (!full_path) {
 648                 free_xid(xid);
 649                 cifs_put_tlink(tlink);
 650                 return ERR_PTR(-ENOMEM);
 651         }
 652
 653         cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode);
 654
 655         rc = -EACCES;
 656         /*
 657          * First try Minshall+French Symlinks, if configured
 658          * and fallback to UNIX Extensions Symlinks.
 659          */
 660         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
 661                 rc = query_mf_symlink(xid, tcon, cifs_sb, full_path,
 662                                       &target_path);
 663
 664         if (rc != 0 && server->ops->query_symlink)
 665                 rc = server->ops->query_symlink(xid, tcon, full_path,
 666                                                 &target_path, cifs_sb);
 667
 668         kfree(full_path);
 669         free_xid(xid);
 670         cifs_put_tlink(tlink);
 671         if (rc != 0) {
 672                 kfree(target_path);
 673                 return ERR_PTR(rc);
 674         }
 675         set_delayed_call(done, kfree_link, target_path);
 676         return target_path;
 677 }
 678
 679 int
 680 cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 681 {
 682         int rc = -EOPNOTSUPP;
 683         unsigned int xid;
 684         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 685         struct tcon_link *tlink;
 686         struct cifs_tcon *pTcon;
 687         char *full_path = NULL;
 688         struct inode *newinode = NULL;
 689
 690         xid = get_xid();
 691
 692         tlink = cifs_sb_tlink(cifs_sb);
 693         if (IS_ERR(tlink)) {
 694                 rc = PTR_ERR(tlink);
 695                 goto symlink_exit;
 696         }
 697         pTcon = tlink_tcon(tlink);
 698
 699         full_path = build_path_from_dentry(direntry);
 700         if (full_path == NULL) {
 701                 rc = -ENOMEM;
 702                 goto symlink_exit;
 703         }
 704
 705         cifs_dbg(FYI, "Full path: %s\n", full_path);
 706         cifs_dbg(FYI, "symname is %s\n", symname);
 707
 708         /* BB what if DFS and this volume is on different share? BB */
 709         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
 710                 rc = create_mf_symlink(xid, pTcon, cifs_sb, full_path, symname);
 711         else if (pTcon->unix_ext)
 712                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 713                                            cifs_sb->local_nls,
 714                                            cifs_remap(cifs_sb));
 715         /* else
 716            rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
 717                                         cifs_sb_target->local_nls); */
 718
 719         if (rc == 0) {
 720                 if (pTcon->unix_ext)
 721                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 722                                                       inode->i_sb, xid);
 723                 else
 724                         rc = cifs_get_inode_info(&newinode, full_path, NULL,
 725                                                  inode->i_sb, xid, NULL);
 726
 727                 if (rc != 0) {
 728                         cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
 729                                  rc);
 730                 } else {
 731                         d_instantiate(direntry, newinode);
 732                 }
 733         }
 734 symlink_exit:
 735         kfree(full_path);
 736         cifs_put_tlink(tlink);
 737         free_xid(xid);
 738         return rc;
 739 }