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., 2002,2008
   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         int dfsplen;
  53         char *full_path;
  54         char dirsep;
  55         struct cifs_sb_info *cifs_sb;
  56
  57         if (direntry == NULL)
  58                 return NULL;  /* not much we can do if dentry is freed and
  59                 we need to reopen the file after it was closed implicitly
  60                 when the server crashed */
  61
  62         cifs_sb = CIFS_SB(direntry->d_sb);
  63         dirsep = CIFS_DIR_SEP(cifs_sb);
  64         pplen = cifs_sb->prepathlen;
  65         if (cifs_sb->tcon && (cifs_sb->tcon->Flags & SMB_SHARE_IS_IN_DFS))
  66                 dfsplen = strnlen(cifs_sb->tcon->treeName, MAX_TREE_SIZE + 1);
  67         else
  68                 dfsplen = 0;
  69 cifs_bp_rename_retry:
  70         namelen = pplen + dfsplen;
  71         for (temp = direntry; !IS_ROOT(temp);) {
  72                 namelen += (1 + temp->d_name.len);
  73                 temp = temp->d_parent;
  74                 if (temp == NULL) {
  75                         cERROR(1, ("corrupt dentry"));
  76                         return NULL;
  77                 }
  78         }
  79
  80         full_path = kmalloc(namelen+1, GFP_KERNEL);
  81         if (full_path == NULL)
  82                 return full_path;
  83         full_path[namelen] = 0; /* trailing null */
  84         for (temp = direntry; !IS_ROOT(temp);) {
  85                 namelen -= 1 + temp->d_name.len;
  86                 if (namelen < 0) {
  87                         break;
  88                 } else {
  89                         full_path[namelen] = dirsep;
  90                         strncpy(full_path + namelen + 1, temp->d_name.name,
  91                                 temp->d_name.len);
  92                         cFYI(0, ("name: %s", full_path + namelen));
  93                 }
  94                 temp = temp->d_parent;
  95                 if (temp == NULL) {
  96                         cERROR(1, ("corrupt dentry"));
  97                         kfree(full_path);
  98                         return NULL;
  99                 }
 100         }
 101         if (namelen != pplen + dfsplen) {
 102                 cERROR(1,
 103                        ("did not end path lookup where expected namelen is %d",
 104                         namelen));
 105                 /* presumably this is only possible if racing with a rename
 106                 of one of the parent directories  (we can not lock the dentries
 107                 above us to prevent this, but retrying should be harmless) */
 108                 kfree(full_path);
 109                 goto cifs_bp_rename_retry;
 110         }
 111         /* DIR_SEP already set for byte  0 / vs \ but not for
 112            subsequent slashes in prepath which currently must
 113            be entered the right way - not sure if there is an alternative
 114            since the '\' is a valid posix character so we can not switch
 115            those safely to '/' if any are found in the middle of the prepath */
 116         /* BB test paths to Windows with '/' in the midst of prepath */
 117
 118         if (dfsplen) {
 119                 strncpy(full_path, cifs_sb->tcon->treeName, dfsplen);
 120                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) {
 121                         int i;
 122                         for (i = 0; i < dfsplen; i++) {
 123                                 if (full_path[i] == '\\')
 124                                         full_path[i] = '/';
 125                         }
 126                 }
 127         }
 128         strncpy(full_path + dfsplen, CIFS_SB(direntry->d_sb)->prepath, pplen);
 129         return full_path;
 130 }
 131
 132 /* Inode operations in similar order to how they appear in Linux file fs.h */
 133
 134 int
 135 cifs_create(struct inode *inode, struct dentry *direntry, int mode,
 136                 struct nameidata *nd)
 137 {
 138         int rc = -ENOENT;
 139         int xid;
 140         int create_options = CREATE_NOT_DIR;
 141         int oplock = 0;
 142         int desiredAccess = GENERIC_READ | GENERIC_WRITE;
 143         __u16 fileHandle;
 144         struct cifs_sb_info *cifs_sb;
 145         struct cifsTconInfo *pTcon;
 146         char *full_path = NULL;
 147         FILE_ALL_INFO *buf = NULL;
 148         struct inode *newinode = NULL;
 149         struct cifsFileInfo *pCifsFile = NULL;
 150         struct cifsInodeInfo *pCifsInode;
 151         int disposition = FILE_OVERWRITE_IF;
 152         bool write_only = false;
 153
 154         xid = GetXid();
 155
 156         cifs_sb = CIFS_SB(inode->i_sb);
 157         pTcon = cifs_sb->tcon;
 158
 159         full_path = build_path_from_dentry(direntry);
 160         if (full_path == NULL) {
 161                 FreeXid(xid);
 162                 return -ENOMEM;
 163         }
 164
 165         if (nd && (nd->flags & LOOKUP_OPEN)) {
 166                 int oflags = nd->intent.open.flags;
 167
 168                 desiredAccess = 0;
 169                 if (oflags & FMODE_READ)
 170                         desiredAccess |= GENERIC_READ;
 171                 if (oflags & FMODE_WRITE) {
 172                         desiredAccess |= GENERIC_WRITE;
 173                         if (!(oflags & FMODE_READ))
 174                                 write_only = true;
 175                 }
 176
 177                 if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
 178                         disposition = FILE_CREATE;
 179                 else if ((oflags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
 180                         disposition = FILE_OVERWRITE_IF;
 181                 else if ((oflags & O_CREAT) == O_CREAT)
 182                         disposition = FILE_OPEN_IF;
 183                 else
 184                         cFYI(1, ("Create flag not set in create function"));
 185         }
 186
 187         /* BB add processing to set equivalent of mode - e.g. via CreateX with
 188            ACLs */
 189         if (oplockEnabled)
 190                 oplock = REQ_OPLOCK;
 191
 192         buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
 193         if (buf == NULL) {
 194                 kfree(full_path);
 195                 FreeXid(xid);
 196                 return -ENOMEM;
 197         }
 198
 199         mode &= ~current->fs->umask;
 200
 201         /*
 202          * if we're not using unix extensions, see if we need to set
 203          * ATTR_READONLY on the create call
 204          */
 205         if (!pTcon->unix_ext && (mode & S_IWUGO) == 0)
 206                 create_options |= CREATE_OPTION_READONLY;
 207
 208         if (cifs_sb->tcon->ses->capabilities & CAP_NT_SMBS)
 209                 rc = CIFSSMBOpen(xid, pTcon, full_path, disposition,
 210                          desiredAccess, create_options,
 211                          &fileHandle, &oplock, buf, cifs_sb->local_nls,
 212                          cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
 213         else
 214                 rc = -EIO; /* no NT SMB support fall into legacy open below */
 215
 216         if (rc == -EIO) {
 217                 /* old server, retry the open legacy style */
 218                 rc = SMBLegacyOpen(xid, pTcon, full_path, disposition,
 219                         desiredAccess, create_options,
 220                         &fileHandle, &oplock, buf, cifs_sb->local_nls,
 221                         cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
 222         }
 223         if (rc) {
 224                 cFYI(1, ("cifs_create returned 0x%x", rc));
 225         } else {
 226                 /* If Open reported that we actually created a file
 227                 then we now have to set the mode if possible */
 228                 if ((pTcon->unix_ext) && (oplock & CIFS_CREATE_ACTION)) {
 229                         struct cifs_unix_set_info_args args = {
 230                                 .mode   = mode,
 231                                 .ctime  = NO_CHANGE_64,
 232                                 .atime  = NO_CHANGE_64,
 233                                 .mtime  = NO_CHANGE_64,
 234                                 .device = 0,
 235                         };
 236
 237                         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
 238                                 args.uid = (__u64) current->fsuid;
 239                                 args.gid = (__u64) current->fsgid;
 240                         } else {
 241                                 args.uid = NO_CHANGE_64;
 242                                 args.gid = NO_CHANGE_64;
 243                         }
 244
 245                         CIFSSMBUnixSetInfo(xid, pTcon, full_path, &args,
 246                                 cifs_sb->local_nls,
 247                                 cifs_sb->mnt_cifs_flags &
 248                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
 249                 } else {
 250                         /* BB implement mode setting via Windows security
 251                            descriptors e.g. */
 252                         /* CIFSSMBWinSetPerms(xid,pTcon,path,mode,-1,-1,nls);*/
 253
 254                         /* Could set r/o dos attribute if mode & 0222 == 0 */
 255                 }
 256
 257                 /* server might mask mode so we have to query for it */
 258                 if (pTcon->unix_ext)
 259                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 260                                                  inode->i_sb, xid);
 261                 else {
 262                         rc = cifs_get_inode_info(&newinode, full_path,
 263                                                  buf, inode->i_sb, xid,
 264                                                  &fileHandle);
 265                         if (newinode) {
 266                                 if (cifs_sb->mnt_cifs_flags &
 267                                     CIFS_MOUNT_DYNPERM)
 268                                         newinode->i_mode = mode;
 269                                 if ((oplock & CIFS_CREATE_ACTION) &&
 270                                     (cifs_sb->mnt_cifs_flags &
 271                                      CIFS_MOUNT_SET_UID)) {
 272                                         newinode->i_uid = current->fsuid;
 273                                         newinode->i_gid = current->fsgid;
 274                                 }
 275                         }
 276                 }
 277
 278                 if (rc != 0) {
 279                         cFYI(1,
 280                              ("Create worked but get_inode_info failed rc = %d",
 281                               rc));
 282                 } else {
 283                         if (pTcon->nocase)
 284                                 direntry->d_op = &cifs_ci_dentry_ops;
 285                         else
 286                                 direntry->d_op = &cifs_dentry_ops;
 287                         d_instantiate(direntry, newinode);
 288                 }
 289                 if ((nd == NULL /* nfsd case - nfs srv does not set nd */) ||
 290                         (!(nd->flags & LOOKUP_OPEN))) {
 291                         /* mknod case - do not leave file open */
 292                         CIFSSMBClose(xid, pTcon, fileHandle);
 293                 } else if (newinode) {
 294                         pCifsFile =
 295                            kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 296
 297                         if (pCifsFile == NULL)
 298                                 goto cifs_create_out;
 299                         pCifsFile->netfid = fileHandle;
 300                         pCifsFile->pid = current->tgid;
 301                         pCifsFile->pInode = newinode;
 302                         pCifsFile->invalidHandle = false;
 303                         pCifsFile->closePend     = false;
 304                         init_MUTEX(&pCifsFile->fh_sem);
 305                         mutex_init(&pCifsFile->lock_mutex);
 306                         INIT_LIST_HEAD(&pCifsFile->llist);
 307                         atomic_set(&pCifsFile->wrtPending, 0);
 308
 309                         /* set the following in open now
 310                                 pCifsFile->pfile = file; */
 311                         write_lock(&GlobalSMBSeslock);
 312                         list_add(&pCifsFile->tlist, &pTcon->openFileList);
 313                         pCifsInode = CIFS_I(newinode);
 314                         if (pCifsInode) {
 315                                 /* if readable file instance put first in list*/
 316                                 if (write_only) {
 317                                         list_add_tail(&pCifsFile->flist,
 318                                                 &pCifsInode->openFileList);
 319                                 } else {
 320                                         list_add(&pCifsFile->flist,
 321                                                 &pCifsInode->openFileList);
 322                                 }
 323                                 if ((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
 324                                         pCifsInode->clientCanCacheAll = true;
 325                                         pCifsInode->clientCanCacheRead = true;
 326                                         cFYI(1, ("Exclusive Oplock inode %p",
 327                                                 newinode));
 328                                 } else if ((oplock & 0xF) == OPLOCK_READ)
 329                                         pCifsInode->clientCanCacheRead = true;
 330                         }
 331                         write_unlock(&GlobalSMBSeslock);
 332                 }
 333         }
 334 cifs_create_out:
 335         kfree(buf);
 336         kfree(full_path);
 337         FreeXid(xid);
 338         return rc;
 339 }
 340
 341 int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
 342                 dev_t device_number)
 343 {
 344         int rc = -EPERM;
 345         int xid;
 346         struct cifs_sb_info *cifs_sb;
 347         struct cifsTconInfo *pTcon;
 348         char *full_path = NULL;
 349         struct inode *newinode = NULL;
 350
 351         if (!old_valid_dev(device_number))
 352                 return -EINVAL;
 353
 354         xid = GetXid();
 355
 356         cifs_sb = CIFS_SB(inode->i_sb);
 357         pTcon = cifs_sb->tcon;
 358
 359         full_path = build_path_from_dentry(direntry);
 360         if (full_path == NULL)
 361                 rc = -ENOMEM;
 362         else if (pTcon->unix_ext) {
 363                 struct cifs_unix_set_info_args args = {
 364                         .mode   = mode & ~current->fs->umask,
 365                         .ctime  = NO_CHANGE_64,
 366                         .atime  = NO_CHANGE_64,
 367                         .mtime  = NO_CHANGE_64,
 368                         .device = device_number,
 369                 };
 370                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
 371                         args.uid = (__u64) current->fsuid;
 372                         args.gid = (__u64) current->fsgid;
 373                 } else {
 374                         args.uid = NO_CHANGE_64;
 375                         args.gid = NO_CHANGE_64;
 376                 }
 377                 rc = CIFSSMBUnixSetInfo(xid, pTcon, full_path,
 378                         &args, cifs_sb->local_nls,
 379                         cifs_sb->mnt_cifs_flags &
 380                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 381
 382                 if (!rc) {
 383                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 384                                                 inode->i_sb, xid);
 385                         if (pTcon->nocase)
 386                                 direntry->d_op = &cifs_ci_dentry_ops;
 387                         else
 388                                 direntry->d_op = &cifs_dentry_ops;
 389                         if (rc == 0)
 390                                 d_instantiate(direntry, newinode);
 391                 }
 392         } else {
 393                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
 394                         int oplock = 0;
 395                         u16 fileHandle;
 396                         FILE_ALL_INFO *buf;
 397
 398                         cFYI(1, ("sfu compat create special file"));
 399
 400                         buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
 401                         if (buf == NULL) {
 402                                 kfree(full_path);
 403                                 FreeXid(xid);
 404                                 return -ENOMEM;
 405                         }
 406
 407                         rc = CIFSSMBOpen(xid, pTcon, full_path,
 408                                          FILE_CREATE, /* fail if exists */
 409                                          GENERIC_WRITE /* BB would
 410                                           WRITE_OWNER | WRITE_DAC be better? */,
 411                                          /* Create a file and set the
 412                                             file attribute to SYSTEM */
 413                                          CREATE_NOT_DIR | CREATE_OPTION_SPECIAL,
 414                                          &fileHandle, &oplock, buf,
 415                                          cifs_sb->local_nls,
 416                                          cifs_sb->mnt_cifs_flags &
 417                                             CIFS_MOUNT_MAP_SPECIAL_CHR);
 418
 419                         /* BB FIXME - add handling for backlevel servers
 420                            which need legacy open and check for all
 421                            calls to SMBOpen for fallback to SMBLeagcyOpen */
 422                         if (!rc) {
 423                                 /* BB Do not bother to decode buf since no
 424                                    local inode yet to put timestamps in,
 425                                    but we can reuse it safely */
 426                                 unsigned int bytes_written;
 427                                 struct win_dev *pdev;
 428                                 pdev = (struct win_dev *)buf;
 429                                 if (S_ISCHR(mode)) {
 430                                         memcpy(pdev->type, "IntxCHR", 8);
 431                                         pdev->major =
 432                                               cpu_to_le64(MAJOR(device_number));
 433                                         pdev->minor =
 434                                               cpu_to_le64(MINOR(device_number));
 435                                         rc = CIFSSMBWrite(xid, pTcon,
 436                                                 fileHandle,
 437                                                 sizeof(struct win_dev),
 438                                                 0, &bytes_written, (char *)pdev,
 439                                                 NULL, 0);
 440                                 } else if (S_ISBLK(mode)) {
 441                                         memcpy(pdev->type, "IntxBLK", 8);
 442                                         pdev->major =
 443                                               cpu_to_le64(MAJOR(device_number));
 444                                         pdev->minor =
 445                                               cpu_to_le64(MINOR(device_number));
 446                                         rc = CIFSSMBWrite(xid, pTcon,
 447                                                 fileHandle,
 448                                                 sizeof(struct win_dev),
 449                                                 0, &bytes_written, (char *)pdev,
 450                                                 NULL, 0);
 451                                 } /* else if(S_ISFIFO */
 452                                 CIFSSMBClose(xid, pTcon, fileHandle);
 453                                 d_drop(direntry);
 454                         }
 455                         kfree(buf);
 456                         /* add code here to set EAs */
 457                 }
 458         }
 459
 460         kfree(full_path);
 461         FreeXid(xid);
 462         return rc;
 463 }
 464
 465
 466 struct dentry *
 467 cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
 468             struct nameidata *nd)
 469 {
 470         int xid;
 471         int rc = 0; /* to get around spurious gcc warning, set to zero here */
 472         struct cifs_sb_info *cifs_sb;
 473         struct cifsTconInfo *pTcon;
 474         struct inode *newInode = NULL;
 475         char *full_path = NULL;
 476
 477         xid = GetXid();
 478
 479         cFYI(1, (" parent inode = 0x%p name is: %s and dentry = 0x%p",
 480               parent_dir_inode, direntry->d_name.name, direntry));
 481
 482         /* check whether path exists */
 483
 484         cifs_sb = CIFS_SB(parent_dir_inode->i_sb);
 485         pTcon = cifs_sb->tcon;
 486
 487         /*
 488          * Don't allow the separator character in a path component.
 489          * The VFS will not allow "/", but "\" is allowed by posix.
 490          */
 491         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)) {
 492                 int i;
 493                 for (i = 0; i < direntry->d_name.len; i++)
 494                         if (direntry->d_name.name[i] == '\\') {
 495                                 cFYI(1, ("Invalid file name"));
 496                                 FreeXid(xid);
 497                                 return ERR_PTR(-EINVAL);
 498                         }
 499         }
 500
 501         /* can not grab the rename sem here since it would
 502         deadlock in the cases (beginning of sys_rename itself)
 503         in which we already have the sb rename sem */
 504         full_path = build_path_from_dentry(direntry);
 505         if (full_path == NULL) {
 506                 FreeXid(xid);
 507                 return ERR_PTR(-ENOMEM);
 508         }
 509
 510         if (direntry->d_inode != NULL) {
 511                 cFYI(1, (" non-NULL inode in lookup"));
 512         } else {
 513                 cFYI(1, (" NULL inode in lookup"));
 514         }
 515         cFYI(1,
 516              (" Full path: %s inode = 0x%p", full_path, direntry->d_inode));
 517
 518         if (pTcon->unix_ext)
 519                 rc = cifs_get_inode_info_unix(&newInode, full_path,
 520                                               parent_dir_inode->i_sb, xid);
 521         else
 522                 rc = cifs_get_inode_info(&newInode, full_path, NULL,
 523                                          parent_dir_inode->i_sb, xid, NULL);
 524
 525         if ((rc == 0) && (newInode != NULL)) {
 526                 if (pTcon->nocase)
 527                         direntry->d_op = &cifs_ci_dentry_ops;
 528                 else
 529                         direntry->d_op = &cifs_dentry_ops;
 530                 d_add(direntry, newInode);
 531
 532                 /* since paths are not looked up by component - the parent
 533                    directories are presumed to be good here */
 534                 renew_parental_timestamps(direntry);
 535
 536         } else if (rc == -ENOENT) {
 537                 rc = 0;
 538                 direntry->d_time = jiffies;
 539                 if (pTcon->nocase)
 540                         direntry->d_op = &cifs_ci_dentry_ops;
 541                 else
 542                         direntry->d_op = &cifs_dentry_ops;
 543                 d_add(direntry, NULL);
 544         /*      if it was once a directory (but how can we tell?) we could do
 545                 shrink_dcache_parent(direntry); */
 546         } else if (rc != -EACCES) {
 547                 cERROR(1, ("Unexpected lookup error %d", rc));
 548                 /* We special case check for Access Denied - since that
 549                 is a common return code */
 550         }
 551
 552         kfree(full_path);
 553         FreeXid(xid);
 554         return ERR_PTR(rc);
 555 }
 556
 557 static int
 558 cifs_d_revalidate(struct dentry *direntry, struct nameidata *nd)
 559 {
 560         int isValid = 1;
 561
 562         if (direntry->d_inode) {
 563                 if (cifs_revalidate(direntry))
 564                         return 0;
 565         } else {
 566                 cFYI(1, ("neg dentry 0x%p name = %s",
 567                          direntry, direntry->d_name.name));
 568                 if (time_after(jiffies, direntry->d_time + HZ) ||
 569                         !lookupCacheEnabled) {
 570                         d_drop(direntry);
 571                         isValid = 0;
 572                 }
 573         }
 574
 575         return isValid;
 576 }
 577
 578 /* static int cifs_d_delete(struct dentry *direntry)
 579 {
 580         int rc = 0;
 581
 582         cFYI(1, ("In cifs d_delete, name = %s", direntry->d_name.name));
 583
 584         return rc;
 585 }     */
 586
 587 struct dentry_operations cifs_dentry_ops = {
 588         .d_revalidate = cifs_d_revalidate,
 589 /* d_delete:       cifs_d_delete,      */ /* not needed except for debugging */
 590 };
 591
 592 static int cifs_ci_hash(struct dentry *dentry, struct qstr *q)
 593 {
 594         struct nls_table *codepage = CIFS_SB(dentry->d_inode->i_sb)->local_nls;
 595         unsigned long hash;
 596         int i;
 597
 598         hash = init_name_hash();
 599         for (i = 0; i < q->len; i++)
 600                 hash = partial_name_hash(nls_tolower(codepage, q->name[i]),
 601                                          hash);
 602         q->hash = end_name_hash(hash);
 603
 604         return 0;
 605 }
 606
 607 static int cifs_ci_compare(struct dentry *dentry, struct qstr *a,
 608                            struct qstr *b)
 609 {
 610         struct nls_table *codepage = CIFS_SB(dentry->d_inode->i_sb)->local_nls;
 611
 612         if ((a->len == b->len) &&
 613             (nls_strnicmp(codepage, a->name, b->name, a->len) == 0)) {
 614                 /*
 615                  * To preserve case, don't let an existing negative dentry's
 616                  * case take precedence.  If a is not a negative dentry, this
 617                  * should have no side effects
 618                  */
 619                 memcpy((void *)a->name, b->name, a->len);
 620                 return 0;
 621         }
 622         return 1;
 623 }
 624
 625 struct dentry_operations cifs_ci_dentry_ops = {
 626         .d_revalidate = cifs_d_revalidate,
 627         .d_hash = cifs_ci_hash,
 628         .d_compare = cifs_ci_compare,
 629 };