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