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   1 /*
   2  *   fs/cifs/dir.c
   3  *
   4  *   vfs operations that deal with dentries
   5  *
   6  *   Copyright (C) International Business Machines  Corp., 2002,2005
   7  *   Author(s): Steve French (sfrench@us.ibm.com)
   8  *
   9  *   This library is free software; you can redistribute it and/or modify
  10  *   it under the terms of the GNU Lesser General Public License as published
  11  *   by the Free Software Foundation; either version 2.1 of the License, or
  12  *   (at your option) any later version.
  13  *
  14  *   This library is distributed in the hope that it will be useful,
  15  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  17  *   the GNU Lesser General Public License for more details.
  18  *
  19  *   You should have received a copy of the GNU Lesser General Public License
  20  *   along with this library; if not, write to the Free Software
  21  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  22  */
  23 #include <linux/fs.h>
  24 #include <linux/stat.h>
  25 #include <linux/slab.h>
  26 #include <linux/namei.h>
  27 #include "cifsfs.h"
  28 #include "cifspdu.h"
  29 #include "cifsglob.h"
  30 #include "cifsproto.h"
  31 #include "cifs_debug.h"
  32 #include "cifs_fs_sb.h"
  33
  34 static void
  35 renew_parental_timestamps(struct dentry *direntry)
  36 {
  37         /* BB check if there is a way to get the kernel to do this or if we
  38            really need this */
  39         do {
  40                 direntry->d_time = jiffies;
  41                 direntry = direntry->d_parent;
  42         } while (!IS_ROOT(direntry));
  43 }
  44
  45 /* Note: caller must free return buffer */
  46 char *
  47 build_path_from_dentry(struct dentry *direntry)
  48 {
  49         struct dentry *temp;
  50         int namelen;
  51         int pplen;
  52         char *full_path;
  53         char dirsep;
  54
  55         if (direntry == NULL)
  56                 return NULL;  /* not much we can do if dentry is freed and
  57                 we need to reopen the file after it was closed implicitly
  58                 when the server crashed */
  59
  60         dirsep = CIFS_DIR_SEP(CIFS_SB(direntry->d_sb));
  61         pplen = CIFS_SB(direntry->d_sb)->prepathlen;
  62 cifs_bp_rename_retry:
  63         namelen = pplen;
  64         for (temp = direntry; !IS_ROOT(temp);) {
  65                 namelen += (1 + temp->d_name.len);
  66                 temp = temp->d_parent;
  67                 if (temp == NULL) {
  68                         cERROR(1, ("corrupt dentry"));
  69                         return NULL;
  70                 }
  71         }
  72
  73         full_path = kmalloc(namelen+1, GFP_KERNEL);
  74         if (full_path == NULL)
  75                 return full_path;
  76         full_path[namelen] = 0; /* trailing null */
  77         for (temp = direntry; !IS_ROOT(temp);) {
  78                 namelen -= 1 + temp->d_name.len;
  79                 if (namelen < 0) {
  80                         break;
  81                 } else {
  82                         full_path[namelen] = dirsep;
  83                         strncpy(full_path + namelen + 1, temp->d_name.name,
  84                                 temp->d_name.len);
  85                         cFYI(0, ("name: %s", full_path + namelen));
  86                 }
  87                 temp = temp->d_parent;
  88                 if (temp == NULL) {
  89                         cERROR(1, ("corrupt dentry"));
  90                         kfree(full_path);
  91                         return NULL;
  92                 }
  93         }
  94         if (namelen != pplen) {
  95                 cERROR(1,
  96                        ("did not end path lookup where expected namelen is %d",
  97                         namelen));
  98                 /* presumably this is only possible if racing with a rename
  99                 of one of the parent directories  (we can not lock the dentries
 100                 above us to prevent this, but retrying should be harmless) */
 101                 kfree(full_path);
 102                 goto cifs_bp_rename_retry;
 103         }
 104         /* DIR_SEP already set for byte  0 / vs \ but not for
 105            subsequent slashes in prepath which currently must
 106            be entered the right way - not sure if there is an alternative
 107            since the '\' is a valid posix character so we can not switch
 108            those safely to '/' if any are found in the middle of the prepath */
 109         /* BB test paths to Windows with '/' in the midst of prepath */
 110         strncpy(full_path, CIFS_SB(direntry->d_sb)->prepath, pplen);
 111         return full_path;
 112 }
 113
 114 /* char * build_wildcard_path_from_dentry(struct dentry *direntry)
 115 {
 116         if(full_path == NULL)
 117                 return full_path;
 118
 119         full_path[namelen] = '\\';
 120         full_path[namelen+1] = '*';
 121         full_path[namelen+2] = 0;
 122 BB remove above eight lines BB */
 123
 124 /* Inode operations in similar order to how they appear in Linux file fs.h */
 125
 126 int
 127 cifs_create(struct inode *inode, struct dentry *direntry, int mode,
 128                 struct nameidata *nd)
 129 {
 130         int rc = -ENOENT;
 131         int xid;
 132         int oplock = 0;
 133         int desiredAccess = GENERIC_READ | GENERIC_WRITE;
 134         __u16 fileHandle;
 135         struct cifs_sb_info *cifs_sb;
 136         struct cifsTconInfo *pTcon;
 137         char *full_path = NULL;
 138         FILE_ALL_INFO * buf = NULL;
 139         struct inode *newinode = NULL;
 140         struct cifsFileInfo * pCifsFile = NULL;
 141         struct cifsInodeInfo * pCifsInode;
 142         int disposition = FILE_OVERWRITE_IF;
 143         int write_only = FALSE;
 144
 145         xid = GetXid();
 146
 147         cifs_sb = CIFS_SB(inode->i_sb);
 148         pTcon = cifs_sb->tcon;
 149
 150         full_path = build_path_from_dentry(direntry);
 151         if (full_path == NULL) {
 152                 FreeXid(xid);
 153                 return -ENOMEM;
 154         }
 155
 156         if (nd && (nd->flags & LOOKUP_OPEN)) {
 157                 int oflags = nd->intent.open.flags;
 158
 159                 desiredAccess = 0;
 160                 if (oflags & FMODE_READ)
 161                         desiredAccess |= GENERIC_READ;
 162                 if (oflags & FMODE_WRITE) {
 163                         desiredAccess |= GENERIC_WRITE;
 164                         if (!(oflags & FMODE_READ))
 165                                 write_only = TRUE;
 166                 }
 167
 168                 if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
 169                         disposition = FILE_CREATE;
 170                 else if ((oflags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
 171                         disposition = FILE_OVERWRITE_IF;
 172                 else if ((oflags & O_CREAT) == O_CREAT)
 173                         disposition = FILE_OPEN_IF;
 174                 else {
 175                         cFYI(1, ("Create flag not set in create function"));
 176                 }
 177         }
 178
 179         /* BB add processing to set equivalent of mode - e.g. via CreateX with
 180            ACLs */
 181         if (oplockEnabled)
 182                 oplock = REQ_OPLOCK;
 183
 184         buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
 185         if (buf == NULL) {
 186                 kfree(full_path);
 187                 FreeXid(xid);
 188                 return -ENOMEM;
 189         }
 190         if (cifs_sb->tcon->ses->capabilities & CAP_NT_SMBS)
 191                 rc = CIFSSMBOpen(xid, pTcon, full_path, disposition,
 192                          desiredAccess, CREATE_NOT_DIR,
 193                          &fileHandle, &oplock, buf, cifs_sb->local_nls,
 194                          cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
 195         else
 196                 rc = -EIO; /* no NT SMB support fall into legacy open below */
 197
 198         if (rc == -EIO) {
 199                 /* old server, retry the open legacy style */
 200                 rc = SMBLegacyOpen(xid, pTcon, full_path, disposition,
 201                         desiredAccess, CREATE_NOT_DIR,
 202                         &fileHandle, &oplock, buf, cifs_sb->local_nls,
 203                         cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
 204         }
 205         if (rc) {
 206                 cFYI(1, ("cifs_create returned 0x%x", rc));
 207         } else {
 208                 /* If Open reported that we actually created a file
 209                 then we now have to set the mode if possible */
 210                 if ((cifs_sb->tcon->ses->capabilities & CAP_UNIX) &&
 211                         (oplock & CIFS_CREATE_ACTION)) {
 212                         mode &= ~current->fs->umask;
 213                         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
 214                                 CIFSSMBUnixSetPerms(xid, pTcon, full_path, mode,
 215                                         (__u64)current->fsuid,
 216                                         (__u64)current->fsgid,
 217                                         0 /* dev */,
 218                                         cifs_sb->local_nls,
 219                                         cifs_sb->mnt_cifs_flags &
 220                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 221                         } else {
 222                                 CIFSSMBUnixSetPerms(xid, pTcon, full_path, mode,
 223                                         (__u64)-1,
 224                                         (__u64)-1,
 225                                         0 /* dev */,
 226                                         cifs_sb->local_nls,
 227                                         cifs_sb->mnt_cifs_flags &
 228                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 229                         }
 230                 } else {
 231                         /* BB implement mode setting via Windows security
 232                            descriptors e.g. */
 233                         /* CIFSSMBWinSetPerms(xid,pTcon,path,mode,-1,-1,nls);*/
 234
 235                         /* Could set r/o dos attribute if mode & 0222 == 0 */
 236                 }
 237
 238         /* BB server might mask mode so we have to query for Unix case*/
 239                 if (pTcon->ses->capabilities & CAP_UNIX)
 240                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 241                                                  inode->i_sb, xid);
 242                 else {
 243                         rc = cifs_get_inode_info(&newinode, full_path,
 244                                                  buf, inode->i_sb, xid);
 245                         if (newinode) {
 246                                 newinode->i_mode = mode;
 247                                 if ((oplock & CIFS_CREATE_ACTION) &&
 248                                     (cifs_sb->mnt_cifs_flags &
 249                                      CIFS_MOUNT_SET_UID)) {
 250                                         newinode->i_uid = current->fsuid;
 251                                         newinode->i_gid = current->fsgid;
 252                                 }
 253                         }
 254                 }
 255
 256                 if (rc != 0) {
 257                         cFYI(1,
 258                              ("Create worked but get_inode_info failed rc = %d",
 259                               rc));
 260                 } else {
 261                         if (pTcon->nocase)
 262                                 direntry->d_op = &cifs_ci_dentry_ops;
 263                         else
 264                                 direntry->d_op = &cifs_dentry_ops;
 265                         d_instantiate(direntry, newinode);
 266                 }
 267                 if ((nd->flags & LOOKUP_OPEN) == FALSE) {
 268                         /* mknod case - do not leave file open */
 269                         CIFSSMBClose(xid, pTcon, fileHandle);
 270                 } else if (newinode) {
 271                         pCifsFile =
 272                            kzalloc(sizeof (struct cifsFileInfo), GFP_KERNEL);
 273
 274                         if (pCifsFile == NULL)
 275                                 goto cifs_create_out;
 276                         pCifsFile->netfid = fileHandle;
 277                         pCifsFile->pid = current->tgid;
 278                         pCifsFile->pInode = newinode;
 279                         pCifsFile->invalidHandle = FALSE;
 280                         pCifsFile->closePend     = FALSE;
 281                         init_MUTEX(&pCifsFile->fh_sem);
 282                         mutex_init(&pCifsFile->lock_mutex);
 283                         INIT_LIST_HEAD(&pCifsFile->llist);
 284                         atomic_set(&pCifsFile->wrtPending, 0);
 285
 286                         /* set the following in open now
 287                                 pCifsFile->pfile = file; */
 288                         write_lock(&GlobalSMBSeslock);
 289                         list_add(&pCifsFile->tlist, &pTcon->openFileList);
 290                         pCifsInode = CIFS_I(newinode);
 291                         if (pCifsInode) {
 292                                 /* if readable file instance put first in list*/
 293                                 if (write_only == TRUE) {
 294                                         list_add_tail(&pCifsFile->flist,
 295                                                 &pCifsInode->openFileList);
 296                                 } else {
 297                                         list_add(&pCifsFile->flist,
 298                                                 &pCifsInode->openFileList);
 299                                 }
 300                                 if ((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
 301                                         pCifsInode->clientCanCacheAll = TRUE;
 302                                         pCifsInode->clientCanCacheRead = TRUE;
 303                                         cFYI(1, ("Exclusive Oplock inode %p",
 304                                                 newinode));
 305                                 } else if ((oplock & 0xF) == OPLOCK_READ)
 306                                         pCifsInode->clientCanCacheRead = TRUE;
 307                         }
 308                         write_unlock(&GlobalSMBSeslock);
 309                 }
 310         }
 311 cifs_create_out:
 312         kfree(buf);
 313         kfree(full_path);
 314         FreeXid(xid);
 315         return rc;
 316 }
 317
 318 int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
 319                 dev_t device_number)
 320 {
 321         int rc = -EPERM;
 322         int xid;
 323         struct cifs_sb_info *cifs_sb;
 324         struct cifsTconInfo *pTcon;
 325         char *full_path = NULL;
 326         struct inode * newinode = NULL;
 327
 328         if (!old_valid_dev(device_number))
 329                 return -EINVAL;
 330
 331         xid = GetXid();
 332
 333         cifs_sb = CIFS_SB(inode->i_sb);
 334         pTcon = cifs_sb->tcon;
 335
 336         full_path = build_path_from_dentry(direntry);
 337         if (full_path == NULL)
 338                 rc = -ENOMEM;
 339         else if (pTcon->ses->capabilities & CAP_UNIX) {
 340                 mode &= ~current->fs->umask;
 341                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
 342                         rc = CIFSSMBUnixSetPerms(xid, pTcon, full_path,
 343                                 mode, (__u64)current->fsuid,
 344                                 (__u64)current->fsgid,
 345                                 device_number, cifs_sb->local_nls,
 346                                 cifs_sb->mnt_cifs_flags &
 347                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
 348                 } else {
 349                         rc = CIFSSMBUnixSetPerms(xid, pTcon,
 350                                 full_path, mode, (__u64)-1, (__u64)-1,
 351                                 device_number, cifs_sb->local_nls,
 352                                 cifs_sb->mnt_cifs_flags &
 353                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
 354                 }
 355
 356                 if (!rc) {
 357                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 358                                                 inode->i_sb, xid);
 359                         if (pTcon->nocase)
 360                                 direntry->d_op = &cifs_ci_dentry_ops;
 361                         else
 362                                 direntry->d_op = &cifs_dentry_ops;
 363                         if (rc == 0)
 364                                 d_instantiate(direntry, newinode);
 365                 }
 366         } else {
 367                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
 368                         int oplock = 0;
 369                         u16 fileHandle;
 370                         FILE_ALL_INFO * buf;
 371
 372                         cFYI(1, ("sfu compat create special file"));
 373
 374                         buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
 375                         if (buf == NULL) {
 376                                 kfree(full_path);
 377                                 FreeXid(xid);
 378                                 return -ENOMEM;
 379                         }
 380
 381                         rc = CIFSSMBOpen(xid, pTcon, full_path,
 382                                          FILE_CREATE, /* fail if exists */
 383                                          GENERIC_WRITE /* BB would
 384                                           WRITE_OWNER | WRITE_DAC be better? */,
 385                                          /* Create a file and set the
 386                                             file attribute to SYSTEM */
 387                                          CREATE_NOT_DIR | CREATE_OPTION_SPECIAL,
 388                                          &fileHandle, &oplock, buf,
 389                                          cifs_sb->local_nls,
 390                                          cifs_sb->mnt_cifs_flags &
 391                                             CIFS_MOUNT_MAP_SPECIAL_CHR);
 392
 393                         /* BB FIXME - add handling for backlevel servers
 394                            which need legacy open and check for all
 395                            calls to SMBOpen for fallback to SMBLeagcyOpen */
 396                         if (!rc) {
 397                                 /* BB Do not bother to decode buf since no
 398                                    local inode yet to put timestamps in,
 399                                    but we can reuse it safely */
 400                                 int bytes_written;
 401                                 struct win_dev *pdev;
 402                                 pdev = (struct win_dev *)buf;
 403                                 if (S_ISCHR(mode)) {
 404                                         memcpy(pdev->type, "IntxCHR", 8);
 405                                         pdev->major =
 406                                               cpu_to_le64(MAJOR(device_number));
 407                                         pdev->minor =
 408                                               cpu_to_le64(MINOR(device_number));
 409                                         rc = CIFSSMBWrite(xid, pTcon,
 410                                                 fileHandle,
 411                                                 sizeof(struct win_dev),
 412                                                 0, &bytes_written, (char *)pdev,
 413                                                 NULL, 0);
 414                                 } else if (S_ISBLK(mode)) {
 415                                         memcpy(pdev->type, "IntxBLK", 8);
 416                                         pdev->major =
 417                                               cpu_to_le64(MAJOR(device_number));
 418                                         pdev->minor =
 419                                               cpu_to_le64(MINOR(device_number));
 420                                         rc = CIFSSMBWrite(xid, pTcon,
 421                                                 fileHandle,
 422                                                 sizeof(struct win_dev),
 423                                                 0, &bytes_written, (char *)pdev,
 424                                                 NULL, 0);
 425                                 } /* else if(S_ISFIFO */
 426                                 CIFSSMBClose(xid, pTcon, fileHandle);
 427                                 d_drop(direntry);
 428                         }
 429                         kfree(buf);
 430                         /* add code here to set EAs */
 431                 }
 432         }
 433
 434         kfree(full_path);
 435         FreeXid(xid);
 436         return rc;
 437 }
 438
 439
 440 struct dentry *
 441 cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
 442             struct nameidata *nd)
 443 {
 444         int xid;
 445         int rc = 0; /* to get around spurious gcc warning, set to zero here */
 446         struct cifs_sb_info *cifs_sb;
 447         struct cifsTconInfo *pTcon;
 448         struct inode *newInode = NULL;
 449         char *full_path = NULL;
 450
 451         xid = GetXid();
 452
 453         cFYI(1,
 454              (" parent inode = 0x%p name is: %s and dentry = 0x%p",
 455               parent_dir_inode, direntry->d_name.name, direntry));
 456
 457         /* check whether path exists */
 458
 459         cifs_sb = CIFS_SB(parent_dir_inode->i_sb);
 460         pTcon = cifs_sb->tcon;
 461
 462         /*
 463          * Don't allow the separator character in a path component.
 464          * The VFS will not allow "/", but "\" is allowed by posix.
 465          */
 466         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)) {
 467                 int i;
 468                 for (i = 0; i < direntry->d_name.len; i++)
 469                         if (direntry->d_name.name[i] == '\\') {
 470                                 cFYI(1, ("Invalid file name"));
 471                                 FreeXid(xid);
 472                                 return ERR_PTR(-EINVAL);
 473                         }
 474         }
 475
 476         /* can not grab the rename sem here since it would
 477         deadlock in the cases (beginning of sys_rename itself)
 478         in which we already have the sb rename sem */
 479         full_path = build_path_from_dentry(direntry);
 480         if (full_path == NULL) {
 481                 FreeXid(xid);
 482                 return ERR_PTR(-ENOMEM);
 483         }
 484
 485         if (direntry->d_inode != NULL) {
 486                 cFYI(1, (" non-NULL inode in lookup"));
 487         } else {
 488                 cFYI(1, (" NULL inode in lookup"));
 489         }
 490         cFYI(1,
 491              (" Full path: %s inode = 0x%p", full_path, direntry->d_inode));
 492
 493         if (pTcon->ses->capabilities & CAP_UNIX)
 494                 rc = cifs_get_inode_info_unix(&newInode, full_path,
 495                                               parent_dir_inode->i_sb, xid);
 496         else
 497                 rc = cifs_get_inode_info(&newInode, full_path, NULL,
 498                                          parent_dir_inode->i_sb, xid);
 499
 500         if ((rc == 0) && (newInode != NULL)) {
 501                 if (pTcon->nocase)
 502                         direntry->d_op = &cifs_ci_dentry_ops;
 503                 else
 504                         direntry->d_op = &cifs_dentry_ops;
 505                 d_add(direntry, newInode);
 506
 507                 /* since paths are not looked up by component - the parent
 508                    directories are presumed to be good here */
 509                 renew_parental_timestamps(direntry);
 510
 511         } else if (rc == -ENOENT) {
 512                 rc = 0;
 513                 direntry->d_time = jiffies;
 514                 if (pTcon->nocase)
 515                         direntry->d_op = &cifs_ci_dentry_ops;
 516                 else
 517                         direntry->d_op = &cifs_dentry_ops;
 518                 d_add(direntry, NULL);
 519         /*      if it was once a directory (but how can we tell?) we could do
 520                 shrink_dcache_parent(direntry); */
 521         } else {
 522                 cERROR(1, ("Error 0x%x on cifs_get_inode_info in lookup of %s",
 523                            rc, full_path));
 524                 /* BB special case check for Access Denied - watch security
 525                 exposure of returning dir info implicitly via different rc
 526                 if file exists or not but no access BB */
 527         }
 528
 529         kfree(full_path);
 530         FreeXid(xid);
 531         return ERR_PTR(rc);
 532 }
 533
 534 static int
 535 cifs_d_revalidate(struct dentry *direntry, struct nameidata *nd)
 536 {
 537         int isValid = 1;
 538
 539         if (direntry->d_inode) {
 540                 if (cifs_revalidate(direntry)) {
 541                         return 0;
 542                 }
 543         } else {
 544                 cFYI(1, ("neg dentry 0x%p name = %s",
 545                          direntry, direntry->d_name.name));
 546                 if (time_after(jiffies, direntry->d_time + HZ) ||
 547                         !lookupCacheEnabled) {
 548                         d_drop(direntry);
 549                         isValid = 0;
 550                 }
 551         }
 552
 553         return isValid;
 554 }
 555
 556 /* static int cifs_d_delete(struct dentry *direntry)
 557 {
 558         int rc = 0;
 559
 560         cFYI(1, ("In cifs d_delete, name = %s", direntry->d_name.name));
 561
 562         return rc;
 563 }     */
 564
 565 struct dentry_operations cifs_dentry_ops = {
 566         .d_revalidate = cifs_d_revalidate,
 567 /* d_delete:       cifs_d_delete,      */ /* not needed except for debugging */
 568 };
 569
 570 static int cifs_ci_hash(struct dentry *dentry, struct qstr *q)
 571 {
 572         struct nls_table *codepage = CIFS_SB(dentry->d_inode->i_sb)->local_nls;
 573         unsigned long hash;
 574         int i;
 575
 576         hash = init_name_hash();
 577         for (i = 0; i < q->len; i++)
 578                 hash = partial_name_hash(nls_tolower(codepage, q->name[i]),
 579                                          hash);
 580         q->hash = end_name_hash(hash);
 581
 582         return 0;
 583 }
 584
 585 static int cifs_ci_compare(struct dentry *dentry, struct qstr *a,
 586                            struct qstr *b)
 587 {
 588         struct nls_table *codepage = CIFS_SB(dentry->d_inode->i_sb)->local_nls;
 589
 590         if ((a->len == b->len) &&
 591             (nls_strnicmp(codepage, a->name, b->name, a->len) == 0)) {
 592                 /*
 593                  * To preserve case, don't let an existing negative dentry's
 594                  * case take precedence.  If a is not a negative dentry, this
 595                  * should have no side effects
 596                  */
 597                 memcpy((unsigned char *)a->name, b->name, a->len);
 598                 return 0;
 599         }
 600         return 1;
 601 }
 602
 603 struct dentry_operations cifs_ci_dentry_ops = {
 604         .d_revalidate = cifs_d_revalidate,
 605         .d_hash = cifs_ci_hash,
 606         .d_compare = cifs_ci_compare,
 607 };