fs/cifs/readdir.c

   1 /*
   2  *   fs/cifs/readdir.c
   3  *
   4  *   Directory search handling
   5  *
   6  *   Copyright (C) International Business Machines  Corp., 2004, 2008
   7  *   Copyright (C) Red Hat, Inc., 2011
   8  *   Author(s): Steve French (sfrench@us.ibm.com)
   9  *
  10  *   This library is free software; you can redistribute it and/or modify
  11  *   it under the terms of the GNU Lesser General Public License as published
  12  *   by the Free Software Foundation; either version 2.1 of the License, or
  13  *   (at your option) any later version.
  14  *
  15  *   This library is distributed in the hope that it will be useful,
  16  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  18  *   the GNU Lesser General Public License for more details.
  19  *
  20  *   You should have received a copy of the GNU Lesser General Public License
  21  *   along with this library; if not, write to the Free Software
  22  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  */
  24 #include <linux/fs.h>
  25 #include <linux/pagemap.h>
  26 #include <linux/slab.h>
  27 #include <linux/stat.h>
  28 #include "cifspdu.h"
  29 #include "cifsglob.h"
  30 #include "cifsproto.h"
  31 #include "cifs_unicode.h"
  32 #include "cifs_debug.h"
  33 #include "cifs_fs_sb.h"
  34 #include "cifsfs.h"
  35
  36 /*
  37  * To be safe - for UCS to UTF-8 with strings loaded with the rare long
  38  * characters alloc more to account for such multibyte target UTF-8
  39  * characters.
  40  */
  41 #define UNICODE_NAME_MAX ((4 * NAME_MAX) + 2)
  42
  43 #ifdef CONFIG_CIFS_DEBUG2
  44 static void dump_cifs_file_struct(struct file *file, char *label)
  45 {
  46         struct cifsFileInfo *cf;
  47
  48         if (file) {
  49                 cf = file->private_data;
  50                 if (cf == NULL) {
  51                         cifs_dbg(FYI, "empty cifs private file data\n");
  52                         return;
  53                 }
  54                 if (cf->invalidHandle)
  55                         cifs_dbg(FYI, "invalid handle\n");
  56                 if (cf->srch_inf.endOfSearch)
  57                         cifs_dbg(FYI, "end of search\n");
  58                 if (cf->srch_inf.emptyDir)
  59                         cifs_dbg(FYI, "empty dir\n");
  60         }
  61 }
  62 #else
  63 static inline void dump_cifs_file_struct(struct file *file, char *label)
  64 {
  65 }
  66 #endif /* DEBUG2 */
  67
  68 /*
  69  * Attempt to preload the dcache with the results from the FIND_FIRST/NEXT
  70  *
  71  * Find the dentry that matches "name". If there isn't one, create one. If it's
  72  * a negative dentry or the uniqueid changed, then drop it and recreate it.
  73  */
  74 static void
  75 cifs_prime_dcache(struct dentry *parent, struct qstr *name,
  76                     struct cifs_fattr *fattr)
  77 {
  78         struct dentry *dentry, *alias;
  79         struct inode *inode;
  80         struct super_block *sb = parent->d_inode->i_sb;
  81         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
  82
  83         cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
  84
  85         dentry = d_hash_and_lookup(parent, name);
  86         if (unlikely(IS_ERR(dentry)))
  87                 return;
  88
  89         if (dentry) {
  90                 int err;
  91
  92                 inode = dentry->d_inode;
  93                 if (inode) {
  94                         /*
  95                          * If we're generating inode numbers, then we don't
  96                          * want to clobber the existing one with the one that
  97                          * the readdir code created.
  98                          */
  99                         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
 100                                 fattr->cf_uniqueid = CIFS_I(inode)->uniqueid;
 101
 102                         /* update inode in place if i_ino didn't change */
 103                         if (CIFS_I(inode)->uniqueid == fattr->cf_uniqueid) {
 104                                 cifs_fattr_to_inode(inode, fattr);
 105                                 goto out;
 106                         }
 107                 }
 108                 err = d_invalidate(dentry);
 109                 dput(dentry);
 110                 if (err)
 111                         return;
 112         }
 113
 114         /*
 115          * If we know that the inode will need to be revalidated immediately,
 116          * then don't create a new dentry for it. We'll end up doing an on
 117          * the wire call either way and this spares us an invalidation.
 118          */
 119         if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
 120                 return;
 121
 122         dentry = d_alloc(parent, name);
 123         if (!dentry)
 124                 return;
 125
 126         inode = cifs_iget(sb, fattr);
 127         if (!inode)
 128                 goto out;
 129
 130         alias = d_materialise_unique(dentry, inode);
 131         if (alias && !IS_ERR(alias))
 132                 dput(alias);
 133 out:
 134         dput(dentry);
 135 }
 136
 137 static void
 138 cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
 139 {
 140         fattr->cf_uid = cifs_sb->mnt_uid;
 141         fattr->cf_gid = cifs_sb->mnt_gid;
 142
 143         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 144                 fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
 145                 fattr->cf_dtype = DT_DIR;
 146         } else {
 147                 fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
 148                 fattr->cf_dtype = DT_REG;
 149         }
 150
 151         if (fattr->cf_cifsattrs & ATTR_READONLY)
 152                 fattr->cf_mode &= ~S_IWUGO;
 153
 154         /*
 155          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
 156          * mark it for revalidation so that "ls -l" will look right. It might
 157          * be super-slow, but if we don't do this then the ownership of files
 158          * may look wrong since the inodes may not have timed out by the time
 159          * "ls" does a stat() call on them.
 160          */
 161         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL)
 162                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 163
 164         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
 165             fattr->cf_cifsattrs & ATTR_SYSTEM) {
 166                 if (fattr->cf_eof == 0)  {
 167                         fattr->cf_mode &= ~S_IFMT;
 168                         fattr->cf_mode |= S_IFIFO;
 169                         fattr->cf_dtype = DT_FIFO;
 170                 } else {
 171                         /*
 172                          * trying to get the type and mode via SFU can be slow,
 173                          * so just call those regular files for now, and mark
 174                          * for reval
 175                          */
 176                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 177                 }
 178         }
 179 }
 180
 181 void
 182 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
 183                        struct cifs_sb_info *cifs_sb)
 184 {
 185         memset(fattr, 0, sizeof(*fattr));
 186         fattr->cf_cifsattrs = le32_to_cpu(info->ExtFileAttributes);
 187         fattr->cf_eof = le64_to_cpu(info->EndOfFile);
 188         fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
 189         fattr->cf_createtime = le64_to_cpu(info->CreationTime);
 190         fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
 191         fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
 192         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
 193
 194         cifs_fill_common_info(fattr, cifs_sb);
 195 }
 196
 197 static void
 198 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 199                        struct cifs_sb_info *cifs_sb)
 200 {
 201         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 202
 203         memset(fattr, 0, sizeof(*fattr));
 204         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
 205                                             info->LastAccessTime, offset);
 206         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
 207                                             info->LastWriteTime, offset);
 208         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
 209                                             info->LastWriteTime, offset);
 210
 211         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
 212         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
 213         fattr->cf_eof = le32_to_cpu(info->DataSize);
 214
 215         cifs_fill_common_info(fattr, cifs_sb);
 216 }
 217
 218 /* BB eventually need to add the following helper function to
 219       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
 220       we try to do FindFirst on (NTFS) directory symlinks */
 221 /*
 222 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 223                              unsigned int xid)
 224 {
 225         __u16 fid;
 226         int len;
 227         int oplock = 0;
 228         int rc;
 229         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
 230         char *tmpbuffer;
 231
 232         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
 233                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 234                         cifs_sb->local_nls,
 235                         cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
 236         if (!rc) {
 237                 tmpbuffer = kmalloc(maxpath);
 238                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
 239                                 tmpbuffer,
 240                                 maxpath -1,
 241                                 fid,
 242                                 cifs_sb->local_nls);
 243                 if (CIFSSMBClose(xid, ptcon, fid)) {
 244                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
 245                 }
 246         }
 247 }
 248  */
 249
 250 static int
 251 initiate_cifs_search(const unsigned int xid, struct file *file)
 252 {
 253         __u16 search_flags;
 254         int rc = 0;
 255         char *full_path = NULL;
 256         struct cifsFileInfo *cifsFile;
 257         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 258         struct tcon_link *tlink = NULL;
 259         struct cifs_tcon *tcon;
 260         struct TCP_Server_Info *server;
 261
 262         if (file->private_data == NULL) {
 263                 tlink = cifs_sb_tlink(cifs_sb);
 264                 if (IS_ERR(tlink))
 265                         return PTR_ERR(tlink);
 266
 267                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 268                 if (cifsFile == NULL) {
 269                         rc = -ENOMEM;
 270                         goto error_exit;
 271                 }
 272                 file->private_data = cifsFile;
 273                 cifsFile->tlink = cifs_get_tlink(tlink);
 274                 tcon = tlink_tcon(tlink);
 275         } else {
 276                 cifsFile = file->private_data;
 277                 tcon = tlink_tcon(cifsFile->tlink);
 278         }
 279
 280         server = tcon->ses->server;
 281
 282         if (!server->ops->query_dir_first) {
 283                 rc = -ENOSYS;
 284                 goto error_exit;
 285         }
 286
 287         cifsFile->invalidHandle = true;
 288         cifsFile->srch_inf.endOfSearch = false;
 289
 290         full_path = build_path_from_dentry(file->f_path.dentry);
 291         if (full_path == NULL) {
 292                 rc = -ENOMEM;
 293                 goto error_exit;
 294         }
 295
 296         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 297
 298 ffirst_retry:
 299         /* test for Unix extensions */
 300         /* but now check for them on the share/mount not on the SMB session */
 301         /* if (cap_unix(tcon->ses) { */
 302         if (tcon->unix_ext)
 303                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 304         else if ((tcon->ses->capabilities &
 305                   tcon->ses->server->vals->cap_nt_find) == 0) {
 306                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 307         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 308                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 309         } else /* not srvinos - BB fixme add check for backlevel? */ {
 310                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 311         }
 312
 313         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 314         if (backup_cred(cifs_sb))
 315                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 316
 317         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 318                                           &cifsFile->fid, search_flags,
 319                                           &cifsFile->srch_inf);
 320
 321         if (rc == 0)
 322                 cifsFile->invalidHandle = false;
 323         /* BB add following call to handle readdir on new NTFS symlink errors
 324         else if STATUS_STOPPED_ON_SYMLINK
 325                 call get_symlink_reparse_path and retry with new path */
 326         else if ((rc == -EOPNOTSUPP) &&
 327                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 328                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 329                 goto ffirst_retry;
 330         }
 331 error_exit:
 332         kfree(full_path);
 333         cifs_put_tlink(tlink);
 334         return rc;
 335 }
 336
 337 /* return length of unicode string in bytes */
 338 static int cifs_unicode_bytelen(const char *str)
 339 {
 340         int len;
 341         const __le16 *ustr = (const __le16 *)str;
 342
 343         for (len = 0; len <= PATH_MAX; len++) {
 344                 if (ustr[len] == 0)
 345                         return len << 1;
 346         }
 347         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 348         return len << 1;
 349 }
 350
 351 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 352 {
 353         char *new_entry;
 354         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 355
 356         if (level == SMB_FIND_FILE_INFO_STANDARD) {
 357                 FIND_FILE_STANDARD_INFO *pfData;
 358                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 359
 360                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
 361                                 pfData->FileNameLength;
 362         } else
 363                 new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset);
 364         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 365         /* validate that new_entry is not past end of SMB */
 366         if (new_entry >= end_of_smb) {
 367                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 368                          new_entry, end_of_smb, old_entry);
 369                 return NULL;
 370         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 371                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
 372                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 373                    (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
 374                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 375                          new_entry, end_of_smb);
 376                 return NULL;
 377         } else
 378                 return new_entry;
 379
 380 }
 381
 382 struct cifs_dirent {
 383         const char      *name;
 384         size_t          namelen;
 385         u32             resume_key;
 386         u64             ino;
 387 };
 388
 389 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 390                 const FILE_UNIX_INFO *info, bool is_unicode)
 391 {
 392         de->name = &info->FileName[0];
 393         if (is_unicode)
 394                 de->namelen = cifs_unicode_bytelen(de->name);
 395         else
 396                 de->namelen = strnlen(de->name, PATH_MAX);
 397         de->resume_key = info->ResumeKey;
 398         de->ino = le64_to_cpu(info->basic.UniqueId);
 399 }
 400
 401 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 402                 const FILE_DIRECTORY_INFO *info)
 403 {
 404         de->name = &info->FileName[0];
 405         de->namelen = le32_to_cpu(info->FileNameLength);
 406         de->resume_key = info->FileIndex;
 407 }
 408
 409 static void cifs_fill_dirent_full(struct cifs_dirent *de,
 410                 const FILE_FULL_DIRECTORY_INFO *info)
 411 {
 412         de->name = &info->FileName[0];
 413         de->namelen = le32_to_cpu(info->FileNameLength);
 414         de->resume_key = info->FileIndex;
 415 }
 416
 417 static void cifs_fill_dirent_search(struct cifs_dirent *de,
 418                 const SEARCH_ID_FULL_DIR_INFO *info)
 419 {
 420         de->name = &info->FileName[0];
 421         de->namelen = le32_to_cpu(info->FileNameLength);
 422         de->resume_key = info->FileIndex;
 423         de->ino = le64_to_cpu(info->UniqueId);
 424 }
 425
 426 static void cifs_fill_dirent_both(struct cifs_dirent *de,
 427                 const FILE_BOTH_DIRECTORY_INFO *info)
 428 {
 429         de->name = &info->FileName[0];
 430         de->namelen = le32_to_cpu(info->FileNameLength);
 431         de->resume_key = info->FileIndex;
 432 }
 433
 434 static void cifs_fill_dirent_std(struct cifs_dirent *de,
 435                 const FIND_FILE_STANDARD_INFO *info)
 436 {
 437         de->name = &info->FileName[0];
 438         /* one byte length, no endianess conversion */
 439         de->namelen = info->FileNameLength;
 440         de->resume_key = info->ResumeKey;
 441 }
 442
 443 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 444                 u16 level, bool is_unicode)
 445 {
 446         memset(de, 0, sizeof(*de));
 447
 448         switch (level) {
 449         case SMB_FIND_FILE_UNIX:
 450                 cifs_fill_dirent_unix(de, info, is_unicode);
 451                 break;
 452         case SMB_FIND_FILE_DIRECTORY_INFO:
 453                 cifs_fill_dirent_dir(de, info);
 454                 break;
 455         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 456                 cifs_fill_dirent_full(de, info);
 457                 break;
 458         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 459                 cifs_fill_dirent_search(de, info);
 460                 break;
 461         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 462                 cifs_fill_dirent_both(de, info);
 463                 break;
 464         case SMB_FIND_FILE_INFO_STANDARD:
 465                 cifs_fill_dirent_std(de, info);
 466                 break;
 467         default:
 468                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 469                 return -EINVAL;
 470         }
 471
 472         return 0;
 473 }
 474
 475 #define UNICODE_DOT cpu_to_le16(0x2e)
 476
 477 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 478 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 479 {
 480         int rc = 0;
 481
 482         if (!de->name)
 483                 return 0;
 484
 485         if (is_unicode) {
 486                 __le16 *ufilename = (__le16 *)de->name;
 487                 if (de->namelen == 2) {
 488                         /* check for . */
 489                         if (ufilename[0] == UNICODE_DOT)
 490                                 rc = 1;
 491                 } else if (de->namelen == 4) {
 492                         /* check for .. */
 493                         if (ufilename[0] == UNICODE_DOT &&
 494                             ufilename[1] == UNICODE_DOT)
 495                                 rc = 2;
 496                 }
 497         } else /* ASCII */ {
 498                 if (de->namelen == 1) {
 499                         if (de->name[0] == '.')
 500                                 rc = 1;
 501                 } else if (de->namelen == 2) {
 502                         if (de->name[0] == '.' && de->name[1] == '.')
 503                                 rc = 2;
 504                 }
 505         }
 506
 507         return rc;
 508 }
 509
 510 /* Check if directory that we are searching has changed so we can decide
 511    whether we can use the cached search results from the previous search */
 512 static int is_dir_changed(struct file *file)
 513 {
 514         struct inode *inode = file_inode(file);
 515         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 516
 517         if (cifsInfo->time == 0)
 518                 return 1; /* directory was changed, perhaps due to unlink */
 519         else
 520                 return 0;
 521
 522 }
 523
 524 static int cifs_save_resume_key(const char *current_entry,
 525         struct cifsFileInfo *file_info)
 526 {
 527         struct cifs_dirent de;
 528         int rc;
 529
 530         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 531                               file_info->srch_inf.unicode);
 532         if (!rc) {
 533                 file_info->srch_inf.presume_name = de.name;
 534                 file_info->srch_inf.resume_name_len = de.namelen;
 535                 file_info->srch_inf.resume_key = de.resume_key;
 536         }
 537         return rc;
 538 }
 539
 540 /*
 541  * Find the corresponding entry in the search. Note that the SMB server returns
 542  * search entries for . and .. which complicates logic here if we choose to
 543  * parse for them and we do not assume that they are located in the findfirst
 544  * return buffer. We start counting in the buffer with entry 2 and increment for
 545  * every entry (do not increment for . or .. entry).
 546  */
 547 static int
 548 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon,
 549                 struct file *file, char **current_entry, int *num_to_ret)
 550 {
 551         __u16 search_flags;
 552         int rc = 0;
 553         int pos_in_buf = 0;
 554         loff_t first_entry_in_buffer;
 555         loff_t index_to_find = file->f_pos;
 556         struct cifsFileInfo *cfile = file->private_data;
 557         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 558         struct TCP_Server_Info *server = tcon->ses->server;
 559         /* check if index in the buffer */
 560
 561         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 562                 return -ENOSYS;
 563
 564         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 565                 return -ENOENT;
 566
 567         *current_entry = NULL;
 568         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 569                                         cfile->srch_inf.entries_in_buffer;
 570
 571         /*
 572          * If first entry in buf is zero then is first buffer
 573          * in search response data which means it is likely . and ..
 574          * will be in this buffer, although some servers do not return
 575          * . and .. for the root of a drive and for those we need
 576          * to start two entries earlier.
 577          */
 578
 579         dump_cifs_file_struct(file, "In fce ");
 580         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 581              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 582                 /* close and restart search */
 583                 cifs_dbg(FYI, "search backing up - close and restart search\n");
 584                 spin_lock(&cifs_file_list_lock);
 585                 if (!cfile->srch_inf.endOfSearch && !cfile->invalidHandle) {
 586                         cfile->invalidHandle = true;
 587                         spin_unlock(&cifs_file_list_lock);
 588                         if (server->ops->close)
 589                                 server->ops->close(xid, tcon, &cfile->fid);
 590                 } else
 591                         spin_unlock(&cifs_file_list_lock);
 592                 if (cfile->srch_inf.ntwrk_buf_start) {
 593                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 594                         if (cfile->srch_inf.smallBuf)
 595                                 cifs_small_buf_release(cfile->srch_inf.
 596                                                 ntwrk_buf_start);
 597                         else
 598                                 cifs_buf_release(cfile->srch_inf.
 599                                                 ntwrk_buf_start);
 600                         cfile->srch_inf.ntwrk_buf_start = NULL;
 601                 }
 602                 rc = initiate_cifs_search(xid, file);
 603                 if (rc) {
 604                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 605                                  rc);
 606                         return rc;
 607                 }
 608                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 609                 if (cfile->srch_inf.last_entry)
 610                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 611         }
 612
 613         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 614         if (backup_cred(cifs_sb))
 615                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 616
 617         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 618                (rc == 0) && !cfile->srch_inf.endOfSearch) {
 619                 cifs_dbg(FYI, "calling findnext2\n");
 620                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 621                                                  search_flags,
 622                                                  &cfile->srch_inf);
 623                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 624                 if (cfile->srch_inf.last_entry)
 625                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 626                 if (rc)
 627                         return -ENOENT;
 628         }
 629         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 630                 /* we found the buffer that contains the entry */
 631                 /* scan and find it */
 632                 int i;
 633                 char *cur_ent;
 634                 char *end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 635                         server->ops->calc_smb_size(
 636                                         cfile->srch_inf.ntwrk_buf_start);
 637
 638                 cur_ent = cfile->srch_inf.srch_entries_start;
 639                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 640                                         - cfile->srch_inf.entries_in_buffer;
 641                 pos_in_buf = index_to_find - first_entry_in_buffer;
 642                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 643
 644                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 645                         /* go entry by entry figuring out which is first */
 646                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 647                                                 cfile->srch_inf.info_level);
 648                 }
 649                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
 650                         /* BB fixme - check if we should flag this error */
 651                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 652                                  pos_in_buf, index_to_find, rc);
 653                 }
 654                 rc = 0;
 655                 *current_entry = cur_ent;
 656         } else {
 657                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 658                 return 0;
 659         }
 660
 661         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 662                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 663                 *num_to_ret = 0;
 664         } else
 665                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 666
 667         return rc;
 668 }
 669
 670 static int cifs_filldir(char *find_entry, struct file *file, filldir_t filldir,
 671                 void *dirent, char *scratch_buf, unsigned int max_len)
 672 {
 673         struct cifsFileInfo *file_info = file->private_data;
 674         struct super_block *sb = file->f_path.dentry->d_sb;
 675         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 676         struct cifs_dirent de = { NULL, };
 677         struct cifs_fattr fattr;
 678         struct qstr name;
 679         int rc = 0;
 680         ino_t ino;
 681
 682         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 683                               file_info->srch_inf.unicode);
 684         if (rc)
 685                 return rc;
 686
 687         if (de.namelen > max_len) {
 688                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 689                          de.namelen);
 690                 return -EINVAL;
 691         }
 692
 693         /* skip . and .. since we added them first */
 694         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 695                 return 0;
 696
 697         if (file_info->srch_inf.unicode) {
 698                 struct nls_table *nlt = cifs_sb->local_nls;
 699
 700                 name.name = scratch_buf;
 701                 name.len =
 702                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 703                                         UNICODE_NAME_MAX,
 704                                         min_t(size_t, de.namelen,
 705                                               (size_t)max_len), nlt,
 706                                         cifs_sb->mnt_cifs_flags &
 707                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 708                 name.len -= nls_nullsize(nlt);
 709         } else {
 710                 name.name = de.name;
 711                 name.len = de.namelen;
 712         }
 713
 714         switch (file_info->srch_inf.info_level) {
 715         case SMB_FIND_FILE_UNIX:
 716                 cifs_unix_basic_to_fattr(&fattr,
 717                                          &((FILE_UNIX_INFO *)find_entry)->basic,
 718                                          cifs_sb);
 719                 break;
 720         case SMB_FIND_FILE_INFO_STANDARD:
 721                 cifs_std_info_to_fattr(&fattr,
 722                                        (FIND_FILE_STANDARD_INFO *)find_entry,
 723                                        cifs_sb);
 724                 break;
 725         default:
 726                 cifs_dir_info_to_fattr(&fattr,
 727                                        (FILE_DIRECTORY_INFO *)find_entry,
 728                                        cifs_sb);
 729                 break;
 730         }
 731
 732         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 733                 fattr.cf_uniqueid = de.ino;
 734         } else {
 735                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
 736                 cifs_autodisable_serverino(cifs_sb);
 737         }
 738
 739         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
 740             CIFSCouldBeMFSymlink(&fattr))
 741                 /*
 742                  * trying to get the type and mode can be slow,
 743                  * so just call those regular files for now, and mark
 744                  * for reval
 745                  */
 746                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
 747
 748         cifs_prime_dcache(file->f_dentry, &name, &fattr);
 749
 750         ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
 751         rc = filldir(dirent, name.name, name.len, file->f_pos, ino,
 752                      fattr.cf_dtype);
 753         return rc;
 754 }
 755
 756
 757 int cifs_readdir(struct file *file, void *direntry, filldir_t filldir)
 758 {
 759         int rc = 0;
 760         unsigned int xid;
 761         int i;
 762         struct cifs_tcon *tcon;
 763         struct cifsFileInfo *cifsFile = NULL;
 764         char *current_entry;
 765         int num_to_fill = 0;
 766         char *tmp_buf = NULL;
 767         char *end_of_smb;
 768         unsigned int max_len;
 769
 770         xid = get_xid();
 771
 772         /*
 773          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
 774          * '..'. Otherwise we won't be able to notify VFS in case of failure.
 775          */
 776         if (file->private_data == NULL) {
 777                 rc = initiate_cifs_search(xid, file);
 778                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
 779                 if (rc)
 780                         goto rddir2_exit;
 781         }
 782
 783         switch ((int) file->f_pos) {
 784         case 0:
 785                 if (filldir(direntry, ".", 1, file->f_pos,
 786                      file_inode(file)->i_ino, DT_DIR) < 0) {
 787                         cifs_dbg(VFS, "Filldir for current dir failed\n");
 788                         rc = -ENOMEM;
 789                         break;
 790                 }
 791                 file->f_pos++;
 792         case 1:
 793                 if (filldir(direntry, "..", 2, file->f_pos,
 794                      parent_ino(file->f_path.dentry), DT_DIR) < 0) {
 795                         cifs_dbg(VFS, "Filldir for parent dir failed\n");
 796                         rc = -ENOMEM;
 797                         break;
 798                 }
 799                 file->f_pos++;
 800         default:
 801                 /* 1) If search is active,
 802                         is in current search buffer?
 803                         if it before then restart search
 804                         if after then keep searching till find it */
 805
 806                 if (file->private_data == NULL) {
 807                         rc = -EINVAL;
 808                         free_xid(xid);
 809                         return rc;
 810                 }
 811                 cifsFile = file->private_data;
 812                 if (cifsFile->srch_inf.endOfSearch) {
 813                         if (cifsFile->srch_inf.emptyDir) {
 814                                 cifs_dbg(FYI, "End of search, empty dir\n");
 815                                 rc = 0;
 816                                 break;
 817                         }
 818                 } /* else {
 819                         cifsFile->invalidHandle = true;
 820                         tcon->ses->server->close(xid, tcon, &cifsFile->fid);
 821                 } */
 822
 823                 tcon = tlink_tcon(cifsFile->tlink);
 824                 rc = find_cifs_entry(xid, tcon, file, &current_entry,
 825                                      &num_to_fill);
 826                 if (rc) {
 827                         cifs_dbg(FYI, "fce error %d\n", rc);
 828                         goto rddir2_exit;
 829                 } else if (current_entry != NULL) {
 830                         cifs_dbg(FYI, "entry %lld found\n", file->f_pos);
 831                 } else {
 832                         cifs_dbg(FYI, "could not find entry\n");
 833                         goto rddir2_exit;
 834                 }
 835                 cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
 836                          num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
 837                 max_len = tcon->ses->server->ops->calc_smb_size(
 838                                 cifsFile->srch_inf.ntwrk_buf_start);
 839                 end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
 840
 841                 tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
 842                 if (tmp_buf == NULL) {
 843                         rc = -ENOMEM;
 844                         break;
 845                 }
 846
 847                 for (i = 0; (i < num_to_fill) && (rc == 0); i++) {
 848                         if (current_entry == NULL) {
 849                                 /* evaluate whether this case is an error */
 850                                 cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
 851                                          num_to_fill, i);
 852                                 break;
 853                         }
 854                         /*
 855                          * if buggy server returns . and .. late do we want to
 856                          * check for that here?
 857                          */
 858                         rc = cifs_filldir(current_entry, file, filldir,
 859                                           direntry, tmp_buf, max_len);
 860                         if (rc == -EOVERFLOW) {
 861                                 rc = 0;
 862                                 break;
 863                         }
 864
 865                         file->f_pos++;
 866                         if (file->f_pos ==
 867                                 cifsFile->srch_inf.index_of_last_entry) {
 868                                 cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
 869                                          file->f_pos, tmp_buf);
 870                                 cifs_save_resume_key(current_entry, cifsFile);
 871                                 break;
 872                         } else
 873                                 current_entry =
 874                                         nxt_dir_entry(current_entry, end_of_smb,
 875                                                 cifsFile->srch_inf.info_level);
 876                 }
 877                 kfree(tmp_buf);
 878                 break;
 879         } /* end switch */
 880
 881 rddir2_exit:
 882         free_xid(xid);
 883         return rc;
 884 }