fs/cifs/dir.c

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