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 #ifdef CONFIG_CIFS_SMB2
  33 #include "smb2proto.h"
  34 #endif
  35
  36 /*
  37  * M-F Symlink Functions - Begin
  38  */
  39
  40 #define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
  41 #define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
  42 #define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
  43 #define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
  44 #define CIFS_MF_SYMLINK_FILE_SIZE \
  45         (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
  46
  47 #define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
  48 #define CIFS_MF_SYMLINK_MD5_FORMAT \
  49         "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n"
  50 #define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) \
  51         md5_hash[0],  md5_hash[1],  md5_hash[2],  md5_hash[3], \
  52         md5_hash[4],  md5_hash[5],  md5_hash[6],  md5_hash[7], \
  53         md5_hash[8],  md5_hash[9],  md5_hash[10], md5_hash[11],\
  54         md5_hash[12], md5_hash[13], md5_hash[14], md5_hash[15]
  55
  56 static int
  57 symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
  58 {
  59         int rc;
  60         unsigned int size;
  61         struct crypto_shash *md5;
  62         struct sdesc *sdescmd5;
  63
  64         md5 = crypto_alloc_shash("md5", 0, 0);
  65         if (IS_ERR(md5)) {
  66                 rc = PTR_ERR(md5);
  67                 cifs_dbg(VFS, "%s: Crypto md5 allocation error %d\n",
  68                          __func__, rc);
  69                 return rc;
  70         }
  71         size = sizeof(struct shash_desc) + crypto_shash_descsize(md5);
  72         sdescmd5 = kmalloc(size, GFP_KERNEL);
  73         if (!sdescmd5) {
  74                 rc = -ENOMEM;
  75                 goto symlink_hash_err;
  76         }
  77         sdescmd5->shash.tfm = md5;
  78         sdescmd5->shash.flags = 0x0;
  79
  80         rc = crypto_shash_init(&sdescmd5->shash);
  81         if (rc) {
  82                 cifs_dbg(VFS, "%s: Could not init md5 shash\n", __func__);
  83                 goto symlink_hash_err;
  84         }
  85         rc = crypto_shash_update(&sdescmd5->shash, link_str, link_len);
  86         if (rc) {
  87                 cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
  88                 goto symlink_hash_err;
  89         }
  90         rc = crypto_shash_final(&sdescmd5->shash, md5_hash);
  91         if (rc)
  92                 cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
  93
  94 symlink_hash_err:
  95         crypto_free_shash(md5);
  96         kfree(sdescmd5);
  97
  98         return rc;
  99 }
 100
 101 static int
 102 parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
 103                  char **_link_str)
 104 {
 105         int rc;
 106         unsigned int link_len;
 107         const char *md5_str1;
 108         const char *link_str;
 109         u8 md5_hash[16];
 110         char md5_str2[34];
 111
 112         if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
 113                 return -EINVAL;
 114
 115         md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
 116         link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
 117
 118         rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
 119         if (rc != 1)
 120                 return -EINVAL;
 121
 122         rc = symlink_hash(link_len, link_str, md5_hash);
 123         if (rc) {
 124                 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
 125                 return rc;
 126         }
 127
 128         snprintf(md5_str2, sizeof(md5_str2),
 129                  CIFS_MF_SYMLINK_MD5_FORMAT,
 130                  CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
 131
 132         if (strncmp(md5_str1, md5_str2, 17) != 0)
 133                 return -EINVAL;
 134
 135         if (_link_str) {
 136                 *_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
 137                 if (!*_link_str)
 138                         return -ENOMEM;
 139         }
 140
 141         *_link_len = link_len;
 142         return 0;
 143 }
 144
 145 static int
 146 format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
 147 {
 148         int rc;
 149         unsigned int link_len;
 150         unsigned int ofs;
 151         u8 md5_hash[16];
 152
 153         if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
 154                 return -EINVAL;
 155
 156         link_len = strlen(link_str);
 157
 158         if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
 159                 return -ENAMETOOLONG;
 160
 161         rc = symlink_hash(link_len, link_str, md5_hash);
 162         if (rc) {
 163                 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
 164                 return rc;
 165         }
 166
 167         snprintf(buf, buf_len,
 168                  CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
 169                  link_len,
 170                  CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
 171
 172         ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
 173         memcpy(buf + ofs, link_str, link_len);
 174
 175         ofs += link_len;
 176         if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
 177                 buf[ofs] = '\n';
 178                 ofs++;
 179         }
 180
 181         while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
 182                 buf[ofs] = ' ';
 183                 ofs++;
 184         }
 185
 186         return 0;
 187 }
 188
 189 bool
 190 couldbe_mf_symlink(const struct cifs_fattr *fattr)
 191 {
 192         if (!S_ISREG(fattr->cf_mode))
 193                 /* it's not a symlink */
 194                 return false;
 195
 196         if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
 197                 /* it's not a symlink */
 198                 return false;
 199
 200         return true;
 201 }
 202
 203 static int
 204 create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 205                   struct cifs_sb_info *cifs_sb, const char *fromName,
 206                   const char *toName)
 207 {
 208         int rc;
 209         u8 *buf;
 210         unsigned int bytes_written = 0;
 211
 212         buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
 213         if (!buf)
 214                 return -ENOMEM;
 215
 216         rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
 217         if (rc)
 218                 goto out;
 219
 220         if (tcon->ses->server->ops->create_mf_symlink)
 221                 rc = tcon->ses->server->ops->create_mf_symlink(xid, tcon,
 222                                         cifs_sb, fromName, buf, &bytes_written);
 223         else
 224                 rc = -EOPNOTSUPP;
 225
 226         if (rc)
 227                 goto out;
 228
 229         if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
 230                 rc = -EIO;
 231 out:
 232         kfree(buf);
 233         return rc;
 234 }
 235
 236 static int
 237 query_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 238                  struct cifs_sb_info *cifs_sb, const unsigned char *path,
 239                  char **symlinkinfo)
 240 {
 241         int rc;
 242         u8 *buf = NULL;
 243         unsigned int link_len = 0;
 244         unsigned int bytes_read = 0;
 245
 246         buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
 247         if (!buf)
 248                 return -ENOMEM;
 249
 250         if (tcon->ses->server->ops->query_mf_symlink)
 251                 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
 252                                               cifs_sb, path, buf, &bytes_read);
 253         else
 254                 rc = -ENOSYS;
 255
 256         if (rc)
 257                 goto out;
 258
 259         if (bytes_read == 0) { /* not a symlink */
 260                 rc = -EINVAL;
 261                 goto out;
 262         }
 263
 264         rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo);
 265 out:
 266         kfree(buf);
 267         return rc;
 268 }
 269
 270 int
 271 check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 272                  struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
 273                  const unsigned char *path)
 274 {
 275         int rc;
 276         u8 *buf = NULL;
 277         unsigned int link_len = 0;
 278         unsigned int bytes_read = 0;
 279
 280         if (!couldbe_mf_symlink(fattr))
 281                 /* it's not a symlink */
 282                 return 0;
 283
 284         buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
 285         if (!buf)
 286                 return -ENOMEM;
 287
 288         if (tcon->ses->server->ops->query_mf_symlink)
 289                 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
 290                                               cifs_sb, path, buf, &bytes_read);
 291         else
 292                 rc = -ENOSYS;
 293
 294         if (rc)
 295                 goto out;
 296
 297         if (bytes_read == 0) /* not a symlink */
 298                 goto out;
 299
 300         rc = parse_mf_symlink(buf, bytes_read, &link_len, NULL);
 301         if (rc == -EINVAL) {
 302                 /* it's not a symlink */
 303                 rc = 0;
 304                 goto out;
 305         }
 306
 307         if (rc != 0)
 308                 goto out;
 309
 310         /* it is a symlink */
 311         fattr->cf_eof = link_len;
 312         fattr->cf_mode &= ~S_IFMT;
 313         fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
 314         fattr->cf_dtype = DT_LNK;
 315 out:
 316         kfree(buf);
 317         return rc;
 318 }
 319
 320 /*
 321  * SMB 1.0 Protocol specific functions
 322  */
 323
 324 int
 325 cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 326                       struct cifs_sb_info *cifs_sb, const unsigned char *path,
 327                       char *pbuf, unsigned int *pbytes_read)
 328 {
 329         int rc;
 330         int oplock = 0;
 331         struct cifs_fid fid;
 332         struct cifs_open_parms oparms;
 333         struct cifs_io_parms io_parms;
 334         int buf_type = CIFS_NO_BUFFER;
 335         FILE_ALL_INFO file_info;
 336
 337         oparms.tcon = tcon;
 338         oparms.cifs_sb = cifs_sb;
 339         oparms.desired_access = GENERIC_READ;
 340         oparms.create_options = CREATE_NOT_DIR;
 341         oparms.disposition = FILE_OPEN;
 342         oparms.path = path;
 343         oparms.fid = &fid;
 344         oparms.reconnect = false;
 345
 346         rc = CIFS_open(xid, &oparms, &oplock, &file_info);
 347         if (rc)
 348                 return rc;
 349
 350         if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
 351                 rc = -ENOENT;
 352                 /* it's not a symlink */
 353                 goto out;
 354         }
 355
 356         io_parms.netfid = fid.netfid;
 357         io_parms.pid = current->tgid;
 358         io_parms.tcon = tcon;
 359         io_parms.offset = 0;
 360         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
 361
 362         rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
 363 out:
 364         CIFSSMBClose(xid, tcon, fid.netfid);
 365         return rc;
 366 }
 367
 368 int
 369 cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 370                        struct cifs_sb_info *cifs_sb, const unsigned char *path,
 371                        char *pbuf, unsigned int *pbytes_written)
 372 {
 373         int rc;
 374         int oplock = 0;
 375         struct cifs_fid fid;
 376         struct cifs_open_parms oparms;
 377         struct cifs_io_parms io_parms;
 378         int create_options = CREATE_NOT_DIR;
 379
 380         if (backup_cred(cifs_sb))
 381                 create_options |= CREATE_OPEN_BACKUP_INTENT;
 382
 383         oparms.tcon = tcon;
 384         oparms.cifs_sb = cifs_sb;
 385         oparms.desired_access = GENERIC_WRITE;
 386         oparms.create_options = create_options;
 387         oparms.disposition = FILE_CREATE;
 388         oparms.path = path;
 389         oparms.fid = &fid;
 390         oparms.reconnect = false;
 391
 392         rc = CIFS_open(xid, &oparms, &oplock, NULL);
 393         if (rc)
 394                 return rc;
 395
 396         io_parms.netfid = fid.netfid;
 397         io_parms.pid = current->tgid;
 398         io_parms.tcon = tcon;
 399         io_parms.offset = 0;
 400         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
 401
 402         rc = CIFSSMBWrite(xid, &io_parms, pbytes_written, pbuf, NULL, 0);
 403         CIFSSMBClose(xid, tcon, fid.netfid);
 404         return rc;
 405 }
 406
 407 /*
 408  * SMB 2.1/SMB3 Protocol specific functions
 409  */
 410 #ifdef CONFIG_CIFS_SMB2
 411 int
 412 smb3_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 413                       struct cifs_sb_info *cifs_sb, const unsigned char *path,
 414                       char *pbuf, unsigned int *pbytes_read)
 415 {
 416         int rc;
 417         struct cifs_fid fid;
 418         struct cifs_open_parms oparms;
 419         struct cifs_io_parms io_parms;
 420         int buf_type = CIFS_NO_BUFFER;
 421         __le16 *utf16_path;
 422         __u8 oplock = SMB2_OPLOCK_LEVEL_II;
 423         struct smb2_file_all_info *pfile_info = NULL;
 424
 425         oparms.tcon = tcon;
 426         oparms.cifs_sb = cifs_sb;
 427         oparms.desired_access = GENERIC_READ;
 428         oparms.create_options = CREATE_NOT_DIR;
 429         if (backup_cred(cifs_sb))
 430                 oparms.create_options |= CREATE_OPEN_BACKUP_INTENT;
 431         oparms.disposition = FILE_OPEN;
 432         oparms.fid = &fid;
 433         oparms.reconnect = false;
 434
 435         utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 436         if (utf16_path == NULL)
 437                 return -ENOMEM;
 438
 439         pfile_info = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2,
 440                              GFP_KERNEL);
 441
 442         if (pfile_info == NULL) {
 443                 kfree(utf16_path);
 444                 return  -ENOMEM;
 445         }
 446
 447         rc = SMB2_open(xid, &oparms, utf16_path, &oplock, pfile_info, NULL);
 448         if (rc)
 449                 goto qmf_out_open_fail;
 450
 451         if (pfile_info->EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
 452                 /* it's not a symlink */
 453                 rc = -ENOENT; /* Is there a better rc to return? */
 454                 goto qmf_out;
 455         }
 456
 457         io_parms.netfid = fid.netfid;
 458         io_parms.pid = current->tgid;
 459         io_parms.tcon = tcon;
 460         io_parms.offset = 0;
 461         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
 462         io_parms.persistent_fid = fid.persistent_fid;
 463         io_parms.volatile_fid = fid.volatile_fid;
 464         rc = SMB2_read(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
 465 qmf_out:
 466         SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
 467 qmf_out_open_fail:
 468         kfree(utf16_path);
 469         kfree(pfile_info);
 470         return rc;
 471 }
 472
 473 int
 474 smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 475                        struct cifs_sb_info *cifs_sb, const unsigned char *path,
 476                        char *pbuf, unsigned int *pbytes_written)
 477 {
 478         int rc;
 479         struct cifs_fid fid;
 480         struct cifs_open_parms oparms;
 481         struct cifs_io_parms io_parms;
 482         int create_options = CREATE_NOT_DIR;
 483         __le16 *utf16_path;
 484         __u8 oplock = SMB2_OPLOCK_LEVEL_EXCLUSIVE;
 485         struct kvec iov[2];
 486
 487         if (backup_cred(cifs_sb))
 488                 create_options |= CREATE_OPEN_BACKUP_INTENT;
 489
 490         cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
 491
 492         utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 493         if (!utf16_path)
 494                 return -ENOMEM;
 495
 496         oparms.tcon = tcon;
 497         oparms.cifs_sb = cifs_sb;
 498         oparms.desired_access = GENERIC_WRITE;
 499         oparms.create_options = create_options;
 500         oparms.disposition = FILE_CREATE;
 501         oparms.fid = &fid;
 502         oparms.reconnect = false;
 503
 504         rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL);
 505         if (rc) {
 506                 kfree(utf16_path);
 507                 return rc;
 508         }
 509
 510         io_parms.netfid = fid.netfid;
 511         io_parms.pid = current->tgid;
 512         io_parms.tcon = tcon;
 513         io_parms.offset = 0;
 514         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
 515         io_parms.persistent_fid = fid.persistent_fid;
 516         io_parms.volatile_fid = fid.volatile_fid;
 517
 518         /* iov[0] is reserved for smb header */
 519         iov[1].iov_base = pbuf;
 520         iov[1].iov_len = CIFS_MF_SYMLINK_FILE_SIZE;
 521
 522         rc = SMB2_write(xid, &io_parms, pbytes_written, iov, 1);
 523
 524         /* Make sure we wrote all of the symlink data */
 525         if ((rc == 0) && (*pbytes_written != CIFS_MF_SYMLINK_FILE_SIZE))
 526                 rc = -EIO;
 527
 528         SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
 529
 530         kfree(utf16_path);
 531         return rc;
 532 }
 533 #endif /* CONFIG_CIFS_SMB2 */
 534
 535 /*
 536  * M-F Symlink Functions - End
 537  */
 538
 539 int
 540 cifs_hardlink(struct dentry *old_file, struct inode *inode,
 541               struct dentry *direntry)
 542 {
 543         int rc = -EACCES;
 544         unsigned int xid;
 545         char *from_name = NULL;
 546         char *to_name = NULL;
 547         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 548         struct tcon_link *tlink;
 549         struct cifs_tcon *tcon;
 550         struct TCP_Server_Info *server;
 551         struct cifsInodeInfo *cifsInode;
 552
 553         tlink = cifs_sb_tlink(cifs_sb);
 554         if (IS_ERR(tlink))
 555                 return PTR_ERR(tlink);
 556         tcon = tlink_tcon(tlink);
 557
 558         xid = get_xid();
 559
 560         from_name = build_path_from_dentry(old_file);
 561         to_name = build_path_from_dentry(direntry);
 562         if ((from_name == NULL) || (to_name == NULL)) {
 563                 rc = -ENOMEM;
 564                 goto cifs_hl_exit;
 565         }
 566
 567         if (tcon->unix_ext)
 568                 rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
 569                                             cifs_sb->local_nls,
 570                                             cifs_remap(cifs_sb));
 571         else {
 572                 server = tcon->ses->server;
 573                 if (!server->ops->create_hardlink) {
 574                         rc = -ENOSYS;
 575                         goto cifs_hl_exit;
 576                 }
 577                 rc = server->ops->create_hardlink(xid, tcon, from_name, to_name,
 578                                                   cifs_sb);
 579                 if ((rc == -EIO) || (rc == -EINVAL))
 580                         rc = -EOPNOTSUPP;
 581         }
 582
 583         d_drop(direntry);       /* force new lookup from server of target */
 584
 585         /*
 586          * if source file is cached (oplocked) revalidate will not go to server
 587          * until the file is closed or oplock broken so update nlinks locally
 588          */
 589         if (d_really_is_positive(old_file)) {
 590                 cifsInode = CIFS_I(d_inode(old_file));
 591                 if (rc == 0) {
 592                         spin_lock(&d_inode(old_file)->i_lock);
 593                         inc_nlink(d_inode(old_file));
 594                         spin_unlock(&d_inode(old_file)->i_lock);
 595
 596                         /*
 597                          * parent dir timestamps will update from srv within a
 598                          * second, would it really be worth it to set the parent
 599                          * dir cifs inode time to zero to force revalidate
 600                          * (faster) for it too?
 601                          */
 602                 }
 603                 /*
 604                  * if not oplocked will force revalidate to get info on source
 605                  * file from srv.  Note Samba server prior to 4.2 has bug -
 606                  * not updating src file ctime on hardlinks but Windows servers
 607                  * handle it properly
 608                  */
 609                 cifsInode->time = 0;
 610
 611                 /*
 612                  * Will update parent dir timestamps from srv within a second.
 613                  * Would it really be worth it to set the parent dir (cifs
 614                  * inode) time field to zero to force revalidate on parent
 615                  * directory faster ie
 616                  *
 617                  * CIFS_I(inode)->time = 0;
 618                  */
 619         }
 620
 621 cifs_hl_exit:
 622         kfree(from_name);
 623         kfree(to_name);
 624         free_xid(xid);
 625         cifs_put_tlink(tlink);
 626         return rc;
 627 }
 628
 629 void *
 630 cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 631 {
 632         struct inode *inode = d_inode(direntry);
 633         int rc = -ENOMEM;
 634         unsigned int xid;
 635         char *full_path = NULL;
 636         char *target_path = NULL;
 637         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 638         struct tcon_link *tlink = NULL;
 639         struct cifs_tcon *tcon;
 640         struct TCP_Server_Info *server;
 641
 642         xid = get_xid();
 643
 644         tlink = cifs_sb_tlink(cifs_sb);
 645         if (IS_ERR(tlink)) {
 646                 rc = PTR_ERR(tlink);
 647                 tlink = NULL;
 648                 goto out;
 649         }
 650         tcon = tlink_tcon(tlink);
 651         server = tcon->ses->server;
 652
 653         full_path = build_path_from_dentry(direntry);
 654         if (!full_path)
 655                 goto out;
 656
 657         cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode);
 658
 659         rc = -EACCES;
 660         /*
 661          * First try Minshall+French Symlinks, if configured
 662          * and fallback to UNIX Extensions Symlinks.
 663          */
 664         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
 665                 rc = query_mf_symlink(xid, tcon, cifs_sb, full_path,
 666                                       &target_path);
 667
 668         if (rc != 0 && server->ops->query_symlink)
 669                 rc = server->ops->query_symlink(xid, tcon, full_path,
 670                                                 &target_path, cifs_sb);
 671
 672         kfree(full_path);
 673 out:
 674         if (rc != 0) {
 675                 kfree(target_path);
 676                 target_path = ERR_PTR(rc);
 677         }
 678
 679         free_xid(xid);
 680         if (tlink)
 681                 cifs_put_tlink(tlink);
 682         nd_set_link(nd, target_path);
 683         return NULL;
 684 }
 685
 686 int
 687 cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 688 {
 689         int rc = -EOPNOTSUPP;
 690         unsigned int xid;
 691         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 692         struct tcon_link *tlink;
 693         struct cifs_tcon *pTcon;
 694         char *full_path = NULL;
 695         struct inode *newinode = NULL;
 696
 697         xid = get_xid();
 698
 699         tlink = cifs_sb_tlink(cifs_sb);
 700         if (IS_ERR(tlink)) {
 701                 rc = PTR_ERR(tlink);
 702                 goto symlink_exit;
 703         }
 704         pTcon = tlink_tcon(tlink);
 705
 706         full_path = build_path_from_dentry(direntry);
 707         if (full_path == NULL) {
 708                 rc = -ENOMEM;
 709                 goto symlink_exit;
 710         }
 711
 712         cifs_dbg(FYI, "Full path: %s\n", full_path);
 713         cifs_dbg(FYI, "symname is %s\n", symname);
 714
 715         /* BB what if DFS and this volume is on different share? BB */
 716         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
 717                 rc = create_mf_symlink(xid, pTcon, cifs_sb, full_path, symname);
 718         else if (pTcon->unix_ext)
 719                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 720                                            cifs_sb->local_nls);
 721         /* else
 722            rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
 723                                         cifs_sb_target->local_nls); */
 724
 725         if (rc == 0) {
 726                 if (pTcon->unix_ext)
 727                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 728                                                       inode->i_sb, xid);
 729                 else
 730                         rc = cifs_get_inode_info(&newinode, full_path, NULL,
 731                                                  inode->i_sb, xid, NULL);
 732
 733                 if (rc != 0) {
 734                         cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
 735                                  rc);
 736                 } else {
 737                         d_instantiate(direntry, newinode);
 738                 }
 739         }
 740 symlink_exit:
 741         kfree(full_path);
 742         cifs_put_tlink(tlink);
 743         free_xid(xid);
 744         return rc;
 745 }