fs/cifs/link.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 /*
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2002,2008
   5  *   Author(s): Steve French ([email protected])
   6  *
   7  */
   8 #include <linux/fs.h>
   9 #include <linux/stat.h>
  10 #include <linux/slab.h>
  11 #include <linux/namei.h>
  12 #include "cifsfs.h"
  13 #include "cifspdu.h"
  14 #include "cifsglob.h"
  15 #include "cifsproto.h"
  16 #include "cifs_debug.h"
  17 #include "cifs_fs_sb.h"
  18 #include "cifs_unicode.h"
  19 #include "smb2proto.h"
  20 #include "cifs_ioctl.h"
  21
  22 /*
  23  * M-F Symlink Functions - Begin
  24  */
  25
  26 #define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
  27 #define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
  28 #define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
  29 #define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
  30 #define CIFS_MF_SYMLINK_FILE_SIZE \
  31         (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
  32
  33 #define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
  34 #define CIFS_MF_SYMLINK_MD5_FORMAT "%16phN\n"
  35 #define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) md5_hash
  36
  37 static int
  38 symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
  39 {
  40         int rc;
  41         struct crypto_shash *md5 = NULL;
  42         struct sdesc *sdescmd5 = NULL;
  43
  44         rc = cifs_alloc_hash("md5", &md5, &sdescmd5);
  45         if (rc)
  46                 goto symlink_hash_err;
  47
  48         rc = crypto_shash_init(&sdescmd5->shash);
  49         if (rc) {
  50                 cifs_dbg(VFS, "%s: Could not init md5 shash\n", __func__);
  51                 goto symlink_hash_err;
  52         }
  53         rc = crypto_shash_update(&sdescmd5->shash, link_str, link_len);
  54         if (rc) {
  55                 cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
  56                 goto symlink_hash_err;
  57         }
  58         rc = crypto_shash_final(&sdescmd5->shash, md5_hash);
  59         if (rc)
  60                 cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
  61
  62 symlink_hash_err:
  63         cifs_free_hash(&md5, &sdescmd5);
  64         return rc;
  65 }
  66
  67 static int
  68 parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
  69                  char **_link_str)
  70 {
  71         int rc;
  72         unsigned int link_len;
  73         const char *md5_str1;
  74         const char *link_str;
  75         u8 md5_hash[16];
  76         char md5_str2[34];
  77
  78         if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
  79                 return -EINVAL;
  80
  81         md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
  82         link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
  83
  84         rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
  85         if (rc != 1)
  86                 return -EINVAL;
  87
  88         if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
  89                 return -EINVAL;
  90
  91         rc = symlink_hash(link_len, link_str, md5_hash);
  92         if (rc) {
  93                 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
  94                 return rc;
  95         }
  96
  97         scnprintf(md5_str2, sizeof(md5_str2),
  98                   CIFS_MF_SYMLINK_MD5_FORMAT,
  99                   CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
 100
 101         if (strncmp(md5_str1, md5_str2, 17) != 0)
 102                 return -EINVAL;
 103
 104         if (_link_str) {
 105                 *_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
 106                 if (!*_link_str)
 107                         return -ENOMEM;
 108         }
 109
 110         *_link_len = link_len;
 111         return 0;
 112 }
 113
 114 static int
 115 format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
 116 {
 117         int rc;
 118         unsigned int link_len;
 119         unsigned int ofs;
 120         u8 md5_hash[16];
 121
 122         if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
 123                 return -EINVAL;
 124
 125         link_len = strlen(link_str);
 126
 127         if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
 128                 return -ENAMETOOLONG;
 129
 130         rc = symlink_hash(link_len, link_str, md5_hash);
 131         if (rc) {
 132                 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
 133                 return rc;
 134         }
 135
 136         scnprintf(buf, buf_len,
 137                   CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
 138                   link_len,
 139                   CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
 140
 141         ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
 142         memcpy(buf + ofs, link_str, link_len);
 143
 144         ofs += link_len;
 145         if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
 146                 buf[ofs] = '\n';
 147                 ofs++;
 148         }
 149
 150         while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
 151                 buf[ofs] = ' ';
 152                 ofs++;
 153         }
 154
 155         return 0;
 156 }
 157
 158 bool
 159 couldbe_mf_symlink(const struct cifs_fattr *fattr)
 160 {
 161         if (!S_ISREG(fattr->cf_mode))
 162                 /* it's not a symlink */
 163                 return false;
 164
 165         if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
 166                 /* it's not a symlink */
 167                 return false;
 168
 169         return true;
 170 }
 171
 172 static int
 173 create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 174                   struct cifs_sb_info *cifs_sb, const char *fromName,
 175                   const char *toName)
 176 {
 177         int rc;
 178         u8 *buf;
 179         unsigned int bytes_written = 0;
 180
 181         buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
 182         if (!buf)
 183                 return -ENOMEM;
 184
 185         rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
 186         if (rc)
 187                 goto out;
 188
 189         if (tcon->ses->server->ops->create_mf_symlink)
 190                 rc = tcon->ses->server->ops->create_mf_symlink(xid, tcon,
 191                                         cifs_sb, fromName, buf, &bytes_written);
 192         else
 193                 rc = -EOPNOTSUPP;
 194
 195         if (rc)
 196                 goto out;
 197
 198         if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
 199                 rc = -EIO;
 200 out:
 201         kfree(buf);
 202         return rc;
 203 }
 204
 205 static int
 206 query_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 207                  struct cifs_sb_info *cifs_sb, const unsigned char *path,
 208                  char **symlinkinfo)
 209 {
 210         int rc;
 211         u8 *buf = NULL;
 212         unsigned int link_len = 0;
 213         unsigned int bytes_read = 0;
 214
 215         buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
 216         if (!buf)
 217                 return -ENOMEM;
 218
 219         if (tcon->ses->server->ops->query_mf_symlink)
 220                 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
 221                                               cifs_sb, path, buf, &bytes_read);
 222         else
 223                 rc = -ENOSYS;
 224
 225         if (rc)
 226                 goto out;
 227
 228         if (bytes_read == 0) { /* not a symlink */
 229                 rc = -EINVAL;
 230                 goto out;
 231         }
 232
 233         rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo);
 234 out:
 235         kfree(buf);
 236         return rc;
 237 }
 238
 239 int
 240 check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 241                  struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
 242                  const unsigned char *path)
 243 {
 244         int rc;
 245         u8 *buf = NULL;
 246         unsigned int link_len = 0;
 247         unsigned int bytes_read = 0;
 248
 249         if (!couldbe_mf_symlink(fattr))
 250                 /* it's not a symlink */
 251                 return 0;
 252
 253         buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
 254         if (!buf)
 255                 return -ENOMEM;
 256
 257         if (tcon->ses->server->ops->query_mf_symlink)
 258                 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
 259                                               cifs_sb, path, buf, &bytes_read);
 260         else
 261                 rc = -ENOSYS;
 262
 263         if (rc)
 264                 goto out;
 265
 266         if (bytes_read == 0) /* not a symlink */
 267                 goto out;
 268
 269         rc = parse_mf_symlink(buf, bytes_read, &link_len, NULL);
 270         if (rc == -EINVAL) {
 271                 /* it's not a symlink */
 272                 rc = 0;
 273                 goto out;
 274         }
 275
 276         if (rc != 0)
 277                 goto out;
 278
 279         /* it is a symlink */
 280         fattr->cf_eof = link_len;
 281         fattr->cf_mode &= ~S_IFMT;
 282         fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
 283         fattr->cf_dtype = DT_LNK;
 284 out:
 285         kfree(buf);
 286         return rc;
 287 }
 288
 289 /*
 290  * SMB 1.0 Protocol specific functions
 291  */
 292
 293 int
 294 cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 295                       struct cifs_sb_info *cifs_sb, const unsigned char *path,
 296                       char *pbuf, unsigned int *pbytes_read)
 297 {
 298         int rc;
 299         int oplock = 0;
 300         struct cifs_fid fid;
 301         struct cifs_open_parms oparms;
 302         struct cifs_io_parms io_parms = {0};
 303         int buf_type = CIFS_NO_BUFFER;
 304         FILE_ALL_INFO file_info;
 305
 306         oparms.tcon = tcon;
 307         oparms.cifs_sb = cifs_sb;
 308         oparms.desired_access = GENERIC_READ;
 309         oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR);
 310         oparms.disposition = FILE_OPEN;
 311         oparms.path = path;
 312         oparms.fid = &fid;
 313         oparms.reconnect = false;
 314
 315         rc = CIFS_open(xid, &oparms, &oplock, &file_info);
 316         if (rc)
 317                 return rc;
 318
 319         if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
 320                 rc = -ENOENT;
 321                 /* it's not a symlink */
 322                 goto out;
 323         }
 324
 325         io_parms.netfid = fid.netfid;
 326         io_parms.pid = current->tgid;
 327         io_parms.tcon = tcon;
 328         io_parms.offset = 0;
 329         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
 330
 331         rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
 332 out:
 333         CIFSSMBClose(xid, tcon, fid.netfid);
 334         return rc;
 335 }
 336
 337 int
 338 cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 339                        struct cifs_sb_info *cifs_sb, const unsigned char *path,
 340                        char *pbuf, unsigned int *pbytes_written)
 341 {
 342         int rc;
 343         int oplock = 0;
 344         struct cifs_fid fid;
 345         struct cifs_open_parms oparms;
 346         struct cifs_io_parms io_parms = {0};
 347
 348         oparms.tcon = tcon;
 349         oparms.cifs_sb = cifs_sb;
 350         oparms.desired_access = GENERIC_WRITE;
 351         oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR);
 352         oparms.disposition = FILE_CREATE;
 353         oparms.path = path;
 354         oparms.fid = &fid;
 355         oparms.reconnect = false;
 356
 357         rc = CIFS_open(xid, &oparms, &oplock, NULL);
 358         if (rc)
 359                 return rc;
 360
 361         io_parms.netfid = fid.netfid;
 362         io_parms.pid = current->tgid;
 363         io_parms.tcon = tcon;
 364         io_parms.offset = 0;
 365         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
 366
 367         rc = CIFSSMBWrite(xid, &io_parms, pbytes_written, pbuf);
 368         CIFSSMBClose(xid, tcon, fid.netfid);
 369         return rc;
 370 }
 371
 372 /*
 373  * SMB 2.1/SMB3 Protocol specific functions
 374  */
 375 int
 376 smb3_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 377                       struct cifs_sb_info *cifs_sb, const unsigned char *path,
 378                       char *pbuf, unsigned int *pbytes_read)
 379 {
 380         int rc;
 381         struct cifs_fid fid;
 382         struct cifs_open_parms oparms;
 383         struct cifs_io_parms io_parms = {0};
 384         int buf_type = CIFS_NO_BUFFER;
 385         __le16 *utf16_path;
 386         __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
 387         struct smb2_file_all_info *pfile_info = NULL;
 388
 389         oparms.tcon = tcon;
 390         oparms.cifs_sb = cifs_sb;
 391         oparms.desired_access = GENERIC_READ;
 392         oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR);
 393         oparms.disposition = FILE_OPEN;
 394         oparms.fid = &fid;
 395         oparms.reconnect = false;
 396
 397         utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 398         if (utf16_path == NULL)
 399                 return -ENOMEM;
 400
 401         pfile_info = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2,
 402                              GFP_KERNEL);
 403
 404         if (pfile_info == NULL) {
 405                 kfree(utf16_path);
 406                 return  -ENOMEM;
 407         }
 408
 409         rc = SMB2_open(xid, &oparms, utf16_path, &oplock, pfile_info, NULL,
 410                        NULL, NULL);
 411         if (rc)
 412                 goto qmf_out_open_fail;
 413
 414         if (pfile_info->EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
 415                 /* it's not a symlink */
 416                 rc = -ENOENT; /* Is there a better rc to return? */
 417                 goto qmf_out;
 418         }
 419
 420         io_parms.netfid = fid.netfid;
 421         io_parms.pid = current->tgid;
 422         io_parms.tcon = tcon;
 423         io_parms.offset = 0;
 424         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
 425         io_parms.persistent_fid = fid.persistent_fid;
 426         io_parms.volatile_fid = fid.volatile_fid;
 427         rc = SMB2_read(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
 428 qmf_out:
 429         SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
 430 qmf_out_open_fail:
 431         kfree(utf16_path);
 432         kfree(pfile_info);
 433         return rc;
 434 }
 435
 436 int
 437 smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 438                        struct cifs_sb_info *cifs_sb, const unsigned char *path,
 439                        char *pbuf, unsigned int *pbytes_written)
 440 {
 441         int rc;
 442         struct cifs_fid fid;
 443         struct cifs_open_parms oparms;
 444         struct cifs_io_parms io_parms = {0};
 445         __le16 *utf16_path;
 446         __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
 447         struct kvec iov[2];
 448
 449         cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
 450
 451         utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 452         if (!utf16_path)
 453                 return -ENOMEM;
 454
 455         oparms.tcon = tcon;
 456         oparms.cifs_sb = cifs_sb;
 457         oparms.desired_access = GENERIC_WRITE;
 458         oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR);
 459         oparms.disposition = FILE_CREATE;
 460         oparms.fid = &fid;
 461         oparms.reconnect = false;
 462
 463         rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL,
 464                        NULL, NULL);
 465         if (rc) {
 466                 kfree(utf16_path);
 467                 return rc;
 468         }
 469
 470         io_parms.netfid = fid.netfid;
 471         io_parms.pid = current->tgid;
 472         io_parms.tcon = tcon;
 473         io_parms.offset = 0;
 474         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
 475         io_parms.persistent_fid = fid.persistent_fid;
 476         io_parms.volatile_fid = fid.volatile_fid;
 477
 478         /* iov[0] is reserved for smb header */
 479         iov[1].iov_base = pbuf;
 480         iov[1].iov_len = CIFS_MF_SYMLINK_FILE_SIZE;
 481
 482         rc = SMB2_write(xid, &io_parms, pbytes_written, iov, 1);
 483
 484         /* Make sure we wrote all of the symlink data */
 485         if ((rc == 0) && (*pbytes_written != CIFS_MF_SYMLINK_FILE_SIZE))
 486                 rc = -EIO;
 487
 488         SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
 489
 490         kfree(utf16_path);
 491         return rc;
 492 }
 493
 494 /*
 495  * M-F Symlink Functions - End
 496  */
 497
 498 int
 499 cifs_hardlink(struct dentry *old_file, struct inode *inode,
 500               struct dentry *direntry)
 501 {
 502         int rc = -EACCES;
 503         unsigned int xid;
 504         const char *from_name, *to_name;
 505         void *page1, *page2;
 506         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 507         struct tcon_link *tlink;
 508         struct cifs_tcon *tcon;
 509         struct TCP_Server_Info *server;
 510         struct cifsInodeInfo *cifsInode;
 511
 512         if (unlikely(cifs_forced_shutdown(cifs_sb)))
 513                 return -EIO;
 514
 515         tlink = cifs_sb_tlink(cifs_sb);
 516         if (IS_ERR(tlink))
 517                 return PTR_ERR(tlink);
 518         tcon = tlink_tcon(tlink);
 519
 520         xid = get_xid();
 521         page1 = alloc_dentry_path();
 522         page2 = alloc_dentry_path();
 523
 524         from_name = build_path_from_dentry(old_file, page1);
 525         if (IS_ERR(from_name)) {
 526                 rc = PTR_ERR(from_name);
 527                 goto cifs_hl_exit;
 528         }
 529         to_name = build_path_from_dentry(direntry, page2);
 530         if (IS_ERR(to_name)) {
 531                 rc = PTR_ERR(to_name);
 532                 goto cifs_hl_exit;
 533         }
 534
 535         if (tcon->unix_ext)
 536                 rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
 537                                             cifs_sb->local_nls,
 538                                             cifs_remap(cifs_sb));
 539         else {
 540                 server = tcon->ses->server;
 541                 if (!server->ops->create_hardlink) {
 542                         rc = -ENOSYS;
 543                         goto cifs_hl_exit;
 544                 }
 545                 rc = server->ops->create_hardlink(xid, tcon, from_name, to_name,
 546                                                   cifs_sb);
 547                 if ((rc == -EIO) || (rc == -EINVAL))
 548                         rc = -EOPNOTSUPP;
 549         }
 550
 551         d_drop(direntry);       /* force new lookup from server of target */
 552
 553         /*
 554          * if source file is cached (oplocked) revalidate will not go to server
 555          * until the file is closed or oplock broken so update nlinks locally
 556          */
 557         if (d_really_is_positive(old_file)) {
 558                 cifsInode = CIFS_I(d_inode(old_file));
 559                 if (rc == 0) {
 560                         spin_lock(&d_inode(old_file)->i_lock);
 561                         inc_nlink(d_inode(old_file));
 562                         spin_unlock(&d_inode(old_file)->i_lock);
 563
 564                         /*
 565                          * parent dir timestamps will update from srv within a
 566                          * second, would it really be worth it to set the parent
 567                          * dir cifs inode time to zero to force revalidate
 568                          * (faster) for it too?
 569                          */
 570                 }
 571                 /*
 572                  * if not oplocked will force revalidate to get info on source
 573                  * file from srv.  Note Samba server prior to 4.2 has bug -
 574                  * not updating src file ctime on hardlinks but Windows servers
 575                  * handle it properly
 576                  */
 577                 cifsInode->time = 0;
 578
 579                 /*
 580                  * Will update parent dir timestamps from srv within a second.
 581                  * Would it really be worth it to set the parent dir (cifs
 582                  * inode) time field to zero to force revalidate on parent
 583                  * directory faster ie
 584                  *
 585                  * CIFS_I(inode)->time = 0;
 586                  */
 587         }
 588
 589 cifs_hl_exit:
 590         free_dentry_path(page1);
 591         free_dentry_path(page2);
 592         free_xid(xid);
 593         cifs_put_tlink(tlink);
 594         return rc;
 595 }
 596
 597 const char *
 598 cifs_get_link(struct dentry *direntry, struct inode *inode,
 599               struct delayed_call *done)
 600 {
 601         int rc = -ENOMEM;
 602         unsigned int xid;
 603         const char *full_path;
 604         void *page;
 605         char *target_path = NULL;
 606         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 607         struct tcon_link *tlink = NULL;
 608         struct cifs_tcon *tcon;
 609         struct TCP_Server_Info *server;
 610
 611         if (!direntry)
 612                 return ERR_PTR(-ECHILD);
 613
 614         xid = get_xid();
 615
 616         tlink = cifs_sb_tlink(cifs_sb);
 617         if (IS_ERR(tlink)) {
 618                 free_xid(xid);
 619                 return ERR_CAST(tlink);
 620         }
 621         tcon = tlink_tcon(tlink);
 622         server = tcon->ses->server;
 623
 624         page = alloc_dentry_path();
 625         full_path = build_path_from_dentry(direntry, page);
 626         if (IS_ERR(full_path)) {
 627                 free_xid(xid);
 628                 cifs_put_tlink(tlink);
 629                 free_dentry_path(page);
 630                 return ERR_CAST(full_path);
 631         }
 632
 633         cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode);
 634
 635         rc = -EACCES;
 636         /*
 637          * First try Minshall+French Symlinks, if configured
 638          * and fallback to UNIX Extensions Symlinks.
 639          */
 640         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
 641                 rc = query_mf_symlink(xid, tcon, cifs_sb, full_path,
 642                                       &target_path);
 643
 644         if (rc != 0 && server->ops->query_symlink) {
 645                 struct cifsInodeInfo *cifsi = CIFS_I(inode);
 646                 bool reparse_point = false;
 647
 648                 if (cifsi->cifsAttrs & ATTR_REPARSE)
 649                         reparse_point = true;
 650
 651                 rc = server->ops->query_symlink(xid, tcon, cifs_sb, full_path,
 652                                                 &target_path, reparse_point);
 653         }
 654
 655         free_dentry_path(page);
 656         free_xid(xid);
 657         cifs_put_tlink(tlink);
 658         if (rc != 0) {
 659                 kfree(target_path);
 660                 return ERR_PTR(rc);
 661         }
 662         set_delayed_call(done, kfree_link, target_path);
 663         return target_path;
 664 }
 665
 666 int
 667 cifs_symlink(struct user_namespace *mnt_userns, struct inode *inode,
 668              struct dentry *direntry, const char *symname)
 669 {
 670         int rc = -EOPNOTSUPP;
 671         unsigned int xid;
 672         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 673         struct tcon_link *tlink;
 674         struct cifs_tcon *pTcon;
 675         const char *full_path;
 676         void *page;
 677         struct inode *newinode = NULL;
 678
 679         if (unlikely(cifs_forced_shutdown(cifs_sb)))
 680                 return -EIO;
 681
 682         page = alloc_dentry_path();
 683         if (!page)
 684                 return -ENOMEM;
 685
 686         xid = get_xid();
 687
 688         tlink = cifs_sb_tlink(cifs_sb);
 689         if (IS_ERR(tlink)) {
 690                 rc = PTR_ERR(tlink);
 691                 goto symlink_exit;
 692         }
 693         pTcon = tlink_tcon(tlink);
 694
 695         full_path = build_path_from_dentry(direntry, page);
 696         if (IS_ERR(full_path)) {
 697                 rc = PTR_ERR(full_path);
 698                 goto symlink_exit;
 699         }
 700
 701         cifs_dbg(FYI, "Full path: %s\n", full_path);
 702         cifs_dbg(FYI, "symname is %s\n", symname);
 703
 704         /* BB what if DFS and this volume is on different share? BB */
 705         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
 706                 rc = create_mf_symlink(xid, pTcon, cifs_sb, full_path, symname);
 707         else if (pTcon->unix_ext)
 708                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 709                                            cifs_sb->local_nls,
 710                                            cifs_remap(cifs_sb));
 711         /* else
 712            rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
 713                                         cifs_sb_target->local_nls); */
 714
 715         if (rc == 0) {
 716                 if (pTcon->posix_extensions)
 717                         rc = smb311_posix_get_inode_info(&newinode, full_path, inode->i_sb, xid);
 718                 else if (pTcon->unix_ext)
 719                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 720                                                       inode->i_sb, xid);
 721                 else
 722                         rc = cifs_get_inode_info(&newinode, full_path, NULL,
 723                                                  inode->i_sb, xid, NULL);
 724
 725                 if (rc != 0) {
 726                         cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
 727                                  rc);
 728                 } else {
 729                         d_instantiate(direntry, newinode);
 730                 }
 731         }
 732 symlink_exit:
 733         free_dentry_path(page);
 734         cifs_put_tlink(tlink);
 735         free_xid(xid);
 736         return rc;
 737 }