Pileus Git - ~andy/linux/blob - 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 /*
 138  * Is it possible that this directory might turn out to be a DFS referral
 139  * once we go to try and use it?
 140  */
 141 static bool
 142 cifs_dfs_is_possible(struct cifs_sb_info *cifs_sb)
 143 {
 144 #ifdef CONFIG_CIFS_DFS_UPCALL
 145         struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
 146
 147         if (tcon->Flags & SMB_SHARE_IS_IN_DFS)
 148                 return true;
 149 #endif
 150         return false;
 151 }
 152
 153 static void
 154 cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
 155 {
 156         fattr->cf_uid = cifs_sb->mnt_uid;
 157         fattr->cf_gid = cifs_sb->mnt_gid;
 158
 159         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 160                 fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
 161                 fattr->cf_dtype = DT_DIR;
 162                 /*
 163                  * Windows CIFS servers generally make DFS referrals look
 164                  * like directories in FIND_* responses with the reparse
 165                  * attribute flag also set (since DFS junctions are
 166                  * reparse points). We must revalidate at least these
 167                  * directory inodes before trying to use them (if
 168                  * they are DFS we will get PATH_NOT_COVERED back
 169                  * when queried directly and can then try to connect
 170                  * to the DFS target)
 171                  */
 172                 if (cifs_dfs_is_possible(cifs_sb) &&
 173                     (fattr->cf_cifsattrs & ATTR_REPARSE))
 174                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 175         } else {
 176                 fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
 177                 fattr->cf_dtype = DT_REG;
 178         }
 179
 180         if (fattr->cf_cifsattrs & ATTR_READONLY)
 181                 fattr->cf_mode &= ~S_IWUGO;
 182
 183         /*
 184          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
 185          * mark it for revalidation so that "ls -l" will look right. It might
 186          * be super-slow, but if we don't do this then the ownership of files
 187          * may look wrong since the inodes may not have timed out by the time
 188          * "ls" does a stat() call on them.
 189          */
 190         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL)
 191                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 192
 193         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
 194             fattr->cf_cifsattrs & ATTR_SYSTEM) {
 195                 if (fattr->cf_eof == 0)  {
 196                         fattr->cf_mode &= ~S_IFMT;
 197                         fattr->cf_mode |= S_IFIFO;
 198                         fattr->cf_dtype = DT_FIFO;
 199                 } else {
 200                         /*
 201                          * trying to get the type and mode via SFU can be slow,
 202                          * so just call those regular files for now, and mark
 203                          * for reval
 204                          */
 205                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 206                 }
 207         }
 208 }
 209
 210 void
 211 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
 212                        struct cifs_sb_info *cifs_sb)
 213 {
 214         memset(fattr, 0, sizeof(*fattr));
 215         fattr->cf_cifsattrs = le32_to_cpu(info->ExtFileAttributes);
 216         fattr->cf_eof = le64_to_cpu(info->EndOfFile);
 217         fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
 218         fattr->cf_createtime = le64_to_cpu(info->CreationTime);
 219         fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
 220         fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
 221         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
 222
 223         cifs_fill_common_info(fattr, cifs_sb);
 224 }
 225
 226 static void
 227 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 228                        struct cifs_sb_info *cifs_sb)
 229 {
 230         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 231
 232         memset(fattr, 0, sizeof(*fattr));
 233         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
 234                                             info->LastAccessTime, offset);
 235         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
 236                                             info->LastWriteTime, offset);
 237         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
 238                                             info->LastWriteTime, offset);
 239
 240         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
 241         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
 242         fattr->cf_eof = le32_to_cpu(info->DataSize);
 243
 244         cifs_fill_common_info(fattr, cifs_sb);
 245 }
 246
 247 /* BB eventually need to add the following helper function to
 248       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
 249       we try to do FindFirst on (NTFS) directory symlinks */
 250 /*
 251 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 252                              unsigned int xid)
 253 {
 254         __u16 fid;
 255         int len;
 256         int oplock = 0;
 257         int rc;
 258         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
 259         char *tmpbuffer;
 260
 261         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
 262                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 263                         cifs_sb->local_nls,
 264                         cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
 265         if (!rc) {
 266                 tmpbuffer = kmalloc(maxpath);
 267                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
 268                                 tmpbuffer,
 269                                 maxpath -1,
 270                                 fid,
 271                                 cifs_sb->local_nls);
 272                 if (CIFSSMBClose(xid, ptcon, fid)) {
 273                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
 274                 }
 275         }
 276 }
 277  */
 278
 279 static int
 280 initiate_cifs_search(const unsigned int xid, struct file *file)
 281 {
 282         __u16 search_flags;
 283         int rc = 0;
 284         char *full_path = NULL;
 285         struct cifsFileInfo *cifsFile;
 286         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 287         struct tcon_link *tlink = NULL;
 288         struct cifs_tcon *tcon;
 289         struct TCP_Server_Info *server;
 290
 291         if (file->private_data == NULL) {
 292                 tlink = cifs_sb_tlink(cifs_sb);
 293                 if (IS_ERR(tlink))
 294                         return PTR_ERR(tlink);
 295
 296                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 297                 if (cifsFile == NULL) {
 298                         rc = -ENOMEM;
 299                         goto error_exit;
 300                 }
 301                 file->private_data = cifsFile;
 302                 cifsFile->tlink = cifs_get_tlink(tlink);
 303                 tcon = tlink_tcon(tlink);
 304         } else {
 305                 cifsFile = file->private_data;
 306                 tcon = tlink_tcon(cifsFile->tlink);
 307         }
 308
 309         server = tcon->ses->server;
 310
 311         if (!server->ops->query_dir_first) {
 312                 rc = -ENOSYS;
 313                 goto error_exit;
 314         }
 315
 316         cifsFile->invalidHandle = true;
 317         cifsFile->srch_inf.endOfSearch = false;
 318
 319         full_path = build_path_from_dentry(file->f_path.dentry);
 320         if (full_path == NULL) {
 321                 rc = -ENOMEM;
 322                 goto error_exit;
 323         }
 324
 325         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 326
 327 ffirst_retry:
 328         /* test for Unix extensions */
 329         /* but now check for them on the share/mount not on the SMB session */
 330         /* if (cap_unix(tcon->ses) { */
 331         if (tcon->unix_ext)
 332                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 333         else if ((tcon->ses->capabilities &
 334                   tcon->ses->server->vals->cap_nt_find) == 0) {
 335                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 336         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 337                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 338         } else /* not srvinos - BB fixme add check for backlevel? */ {
 339                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 340         }
 341
 342         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 343         if (backup_cred(cifs_sb))
 344                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 345
 346         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 347                                           &cifsFile->fid, search_flags,
 348                                           &cifsFile->srch_inf);
 349
 350         if (rc == 0)
 351                 cifsFile->invalidHandle = false;
 352         /* BB add following call to handle readdir on new NTFS symlink errors
 353         else if STATUS_STOPPED_ON_SYMLINK
 354                 call get_symlink_reparse_path and retry with new path */
 355         else if ((rc == -EOPNOTSUPP) &&
 356                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 357                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 358                 goto ffirst_retry;
 359         }
 360 error_exit:
 361         kfree(full_path);
 362         cifs_put_tlink(tlink);
 363         return rc;
 364 }
 365
 366 /* return length of unicode string in bytes */
 367 static int cifs_unicode_bytelen(const char *str)
 368 {
 369         int len;
 370         const __le16 *ustr = (const __le16 *)str;
 371
 372         for (len = 0; len <= PATH_MAX; len++) {
 373                 if (ustr[len] == 0)
 374                         return len << 1;
 375         }
 376         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 377         return len << 1;
 378 }
 379
 380 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 381 {
 382         char *new_entry;
 383         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 384
 385         if (level == SMB_FIND_FILE_INFO_STANDARD) {
 386                 FIND_FILE_STANDARD_INFO *pfData;
 387                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 388
 389                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
 390                                 pfData->FileNameLength;
 391         } else
 392                 new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset);
 393         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 394         /* validate that new_entry is not past end of SMB */
 395         if (new_entry >= end_of_smb) {
 396                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 397                          new_entry, end_of_smb, old_entry);
 398                 return NULL;
 399         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 400                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
 401                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 402                    (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
 403                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 404                          new_entry, end_of_smb);
 405                 return NULL;
 406         } else
 407                 return new_entry;
 408
 409 }
 410
 411 struct cifs_dirent {
 412         const char      *name;
 413         size_t          namelen;
 414         u32             resume_key;
 415         u64             ino;
 416 };
 417
 418 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 419                 const FILE_UNIX_INFO *info, bool is_unicode)
 420 {
 421         de->name = &info->FileName[0];
 422         if (is_unicode)
 423                 de->namelen = cifs_unicode_bytelen(de->name);
 424         else
 425                 de->namelen = strnlen(de->name, PATH_MAX);
 426         de->resume_key = info->ResumeKey;
 427         de->ino = le64_to_cpu(info->basic.UniqueId);
 428 }
 429
 430 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 431                 const FILE_DIRECTORY_INFO *info)
 432 {
 433         de->name = &info->FileName[0];
 434         de->namelen = le32_to_cpu(info->FileNameLength);
 435         de->resume_key = info->FileIndex;
 436 }
 437
 438 static void cifs_fill_dirent_full(struct cifs_dirent *de,
 439                 const FILE_FULL_DIRECTORY_INFO *info)
 440 {
 441         de->name = &info->FileName[0];
 442         de->namelen = le32_to_cpu(info->FileNameLength);
 443         de->resume_key = info->FileIndex;
 444 }
 445
 446 static void cifs_fill_dirent_search(struct cifs_dirent *de,
 447                 const SEARCH_ID_FULL_DIR_INFO *info)
 448 {
 449         de->name = &info->FileName[0];
 450         de->namelen = le32_to_cpu(info->FileNameLength);
 451         de->resume_key = info->FileIndex;
 452         de->ino = le64_to_cpu(info->UniqueId);
 453 }
 454
 455 static void cifs_fill_dirent_both(struct cifs_dirent *de,
 456                 const FILE_BOTH_DIRECTORY_INFO *info)
 457 {
 458         de->name = &info->FileName[0];
 459         de->namelen = le32_to_cpu(info->FileNameLength);
 460         de->resume_key = info->FileIndex;
 461 }
 462
 463 static void cifs_fill_dirent_std(struct cifs_dirent *de,
 464                 const FIND_FILE_STANDARD_INFO *info)
 465 {
 466         de->name = &info->FileName[0];
 467         /* one byte length, no endianess conversion */
 468         de->namelen = info->FileNameLength;
 469         de->resume_key = info->ResumeKey;
 470 }
 471
 472 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 473                 u16 level, bool is_unicode)
 474 {
 475         memset(de, 0, sizeof(*de));
 476
 477         switch (level) {
 478         case SMB_FIND_FILE_UNIX:
 479                 cifs_fill_dirent_unix(de, info, is_unicode);
 480                 break;
 481         case SMB_FIND_FILE_DIRECTORY_INFO:
 482                 cifs_fill_dirent_dir(de, info);
 483                 break;
 484         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 485                 cifs_fill_dirent_full(de, info);
 486                 break;
 487         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 488                 cifs_fill_dirent_search(de, info);
 489                 break;
 490         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 491                 cifs_fill_dirent_both(de, info);
 492                 break;
 493         case SMB_FIND_FILE_INFO_STANDARD:
 494                 cifs_fill_dirent_std(de, info);
 495                 break;
 496         default:
 497                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 498                 return -EINVAL;
 499         }
 500
 501         return 0;
 502 }
 503
 504 #define UNICODE_DOT cpu_to_le16(0x2e)
 505
 506 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 507 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 508 {
 509         int rc = 0;
 510
 511         if (!de->name)
 512                 return 0;
 513
 514         if (is_unicode) {
 515                 __le16 *ufilename = (__le16 *)de->name;
 516                 if (de->namelen == 2) {
 517                         /* check for . */
 518                         if (ufilename[0] == UNICODE_DOT)
 519                                 rc = 1;
 520                 } else if (de->namelen == 4) {
 521                         /* check for .. */
 522                         if (ufilename[0] == UNICODE_DOT &&
 523                             ufilename[1] == UNICODE_DOT)
 524                                 rc = 2;
 525                 }
 526         } else /* ASCII */ {
 527                 if (de->namelen == 1) {
 528                         if (de->name[0] == '.')
 529                                 rc = 1;
 530                 } else if (de->namelen == 2) {
 531                         if (de->name[0] == '.' && de->name[1] == '.')
 532                                 rc = 2;
 533                 }
 534         }
 535
 536         return rc;
 537 }
 538
 539 /* Check if directory that we are searching has changed so we can decide
 540    whether we can use the cached search results from the previous search */
 541 static int is_dir_changed(struct file *file)
 542 {
 543         struct inode *inode = file_inode(file);
 544         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 545
 546         if (cifsInfo->time == 0)
 547                 return 1; /* directory was changed, perhaps due to unlink */
 548         else
 549                 return 0;
 550
 551 }
 552
 553 static int cifs_save_resume_key(const char *current_entry,
 554         struct cifsFileInfo *file_info)
 555 {
 556         struct cifs_dirent de;
 557         int rc;
 558
 559         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 560                               file_info->srch_inf.unicode);
 561         if (!rc) {
 562                 file_info->srch_inf.presume_name = de.name;
 563                 file_info->srch_inf.resume_name_len = de.namelen;
 564                 file_info->srch_inf.resume_key = de.resume_key;
 565         }
 566         return rc;
 567 }
 568
 569 /*
 570  * Find the corresponding entry in the search. Note that the SMB server returns
 571  * search entries for . and .. which complicates logic here if we choose to
 572  * parse for them and we do not assume that they are located in the findfirst
 573  * return buffer. We start counting in the buffer with entry 2 and increment for
 574  * every entry (do not increment for . or .. entry).
 575  */
 576 static int
 577 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
 578                 struct file *file, char **current_entry, int *num_to_ret)
 579 {
 580         __u16 search_flags;
 581         int rc = 0;
 582         int pos_in_buf = 0;
 583         loff_t first_entry_in_buffer;
 584         loff_t index_to_find = pos;
 585         struct cifsFileInfo *cfile = file->private_data;
 586         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 587         struct TCP_Server_Info *server = tcon->ses->server;
 588         /* check if index in the buffer */
 589
 590         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 591                 return -ENOSYS;
 592
 593         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 594                 return -ENOENT;
 595
 596         *current_entry = NULL;
 597         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 598                                         cfile->srch_inf.entries_in_buffer;
 599
 600         /*
 601          * If first entry in buf is zero then is first buffer
 602          * in search response data which means it is likely . and ..
 603          * will be in this buffer, although some servers do not return
 604          * . and .. for the root of a drive and for those we need
 605          * to start two entries earlier.
 606          */
 607
 608         dump_cifs_file_struct(file, "In fce ");
 609         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 610              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 611                 /* close and restart search */
 612                 cifs_dbg(FYI, "search backing up - close and restart search\n");
 613                 spin_lock(&cifs_file_list_lock);
 614                 if (!cfile->srch_inf.endOfSearch && !cfile->invalidHandle) {
 615                         cfile->invalidHandle = true;
 616                         spin_unlock(&cifs_file_list_lock);
 617                         if (server->ops->close)
 618                                 server->ops->close(xid, tcon, &cfile->fid);
 619                 } else
 620                         spin_unlock(&cifs_file_list_lock);
 621                 if (cfile->srch_inf.ntwrk_buf_start) {
 622                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 623                         if (cfile->srch_inf.smallBuf)
 624                                 cifs_small_buf_release(cfile->srch_inf.
 625                                                 ntwrk_buf_start);
 626                         else
 627                                 cifs_buf_release(cfile->srch_inf.
 628                                                 ntwrk_buf_start);
 629                         cfile->srch_inf.ntwrk_buf_start = NULL;
 630                 }
 631                 rc = initiate_cifs_search(xid, file);
 632                 if (rc) {
 633                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 634                                  rc);
 635                         return rc;
 636                 }
 637                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 638                 if (cfile->srch_inf.last_entry)
 639                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 640         }
 641
 642         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 643         if (backup_cred(cifs_sb))
 644                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 645
 646         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 647                (rc == 0) && !cfile->srch_inf.endOfSearch) {
 648                 cifs_dbg(FYI, "calling findnext2\n");
 649                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 650                                                  search_flags,
 651                                                  &cfile->srch_inf);
 652                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 653                 if (cfile->srch_inf.last_entry)
 654                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 655                 if (rc)
 656                         return -ENOENT;
 657         }
 658         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 659                 /* we found the buffer that contains the entry */
 660                 /* scan and find it */
 661                 int i;
 662                 char *cur_ent;
 663                 char *end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 664                         server->ops->calc_smb_size(
 665                                         cfile->srch_inf.ntwrk_buf_start);
 666
 667                 cur_ent = cfile->srch_inf.srch_entries_start;
 668                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 669                                         - cfile->srch_inf.entries_in_buffer;
 670                 pos_in_buf = index_to_find - first_entry_in_buffer;
 671                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 672
 673                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 674                         /* go entry by entry figuring out which is first */
 675                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 676                                                 cfile->srch_inf.info_level);
 677                 }
 678                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
 679                         /* BB fixme - check if we should flag this error */
 680                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 681                                  pos_in_buf, index_to_find, rc);
 682                 }
 683                 rc = 0;
 684                 *current_entry = cur_ent;
 685         } else {
 686                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 687                 return 0;
 688         }
 689
 690         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 691                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 692                 *num_to_ret = 0;
 693         } else
 694                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 695
 696         return rc;
 697 }
 698
 699 static int cifs_filldir(char *find_entry, struct file *file,
 700                 struct dir_context *ctx,
 701                 char *scratch_buf, unsigned int max_len)
 702 {
 703         struct cifsFileInfo *file_info = file->private_data;
 704         struct super_block *sb = file->f_path.dentry->d_sb;
 705         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 706         struct cifs_dirent de = { NULL, };
 707         struct cifs_fattr fattr;
 708         struct qstr name;
 709         int rc = 0;
 710         ino_t ino;
 711
 712         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 713                               file_info->srch_inf.unicode);
 714         if (rc)
 715                 return rc;
 716
 717         if (de.namelen > max_len) {
 718                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 719                          de.namelen);
 720                 return -EINVAL;
 721         }
 722
 723         /* skip . and .. since we added them first */
 724         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 725                 return 0;
 726
 727         if (file_info->srch_inf.unicode) {
 728                 struct nls_table *nlt = cifs_sb->local_nls;
 729
 730                 name.name = scratch_buf;
 731                 name.len =
 732                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 733                                         UNICODE_NAME_MAX,
 734                                         min_t(size_t, de.namelen,
 735                                               (size_t)max_len), nlt,
 736                                         cifs_sb->mnt_cifs_flags &
 737                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 738                 name.len -= nls_nullsize(nlt);
 739         } else {
 740                 name.name = de.name;
 741                 name.len = de.namelen;
 742         }
 743
 744         switch (file_info->srch_inf.info_level) {
 745         case SMB_FIND_FILE_UNIX:
 746                 cifs_unix_basic_to_fattr(&fattr,
 747                                          &((FILE_UNIX_INFO *)find_entry)->basic,
 748                                          cifs_sb);
 749                 break;
 750         case SMB_FIND_FILE_INFO_STANDARD:
 751                 cifs_std_info_to_fattr(&fattr,
 752                                        (FIND_FILE_STANDARD_INFO *)find_entry,
 753                                        cifs_sb);
 754                 break;
 755         default:
 756                 cifs_dir_info_to_fattr(&fattr,
 757                                        (FILE_DIRECTORY_INFO *)find_entry,
 758                                        cifs_sb);
 759                 break;
 760         }
 761
 762         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 763                 fattr.cf_uniqueid = de.ino;
 764         } else {
 765                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
 766                 cifs_autodisable_serverino(cifs_sb);
 767         }
 768
 769         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
 770             CIFSCouldBeMFSymlink(&fattr))
 771                 /*
 772                  * trying to get the type and mode can be slow,
 773                  * so just call those regular files for now, and mark
 774                  * for reval
 775                  */
 776                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
 777
 778         cifs_prime_dcache(file->f_dentry, &name, &fattr);
 779
 780         ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
 781         return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
 782 }
 783
 784
 785 int cifs_readdir(struct file *file, struct dir_context *ctx)
 786 {
 787         int rc = 0;
 788         unsigned int xid;
 789         int i;
 790         struct cifs_tcon *tcon;
 791         struct cifsFileInfo *cifsFile = NULL;
 792         char *current_entry;
 793         int num_to_fill = 0;
 794         char *tmp_buf = NULL;
 795         char *end_of_smb;
 796         unsigned int max_len;
 797
 798         xid = get_xid();
 799
 800         /*
 801          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
 802          * '..'. Otherwise we won't be able to notify VFS in case of failure.
 803          */
 804         if (file->private_data == NULL) {
 805                 rc = initiate_cifs_search(xid, file);
 806                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
 807                 if (rc)
 808                         goto rddir2_exit;
 809         }
 810
 811         if (!dir_emit_dots(file, ctx))
 812                 goto rddir2_exit;
 813
 814         /* 1) If search is active,
 815                 is in current search buffer?
 816                 if it before then restart search
 817                 if after then keep searching till find it */
 818
 819         if (file->private_data == NULL) {
 820                 rc = -EINVAL;
 821                 goto rddir2_exit;
 822         }
 823         cifsFile = file->private_data;
 824         if (cifsFile->srch_inf.endOfSearch) {
 825                 if (cifsFile->srch_inf.emptyDir) {
 826                         cifs_dbg(FYI, "End of search, empty dir\n");
 827                         rc = 0;
 828                         goto rddir2_exit;
 829                 }
 830         } /* else {
 831                 cifsFile->invalidHandle = true;
 832                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
 833         } */
 834
 835         tcon = tlink_tcon(cifsFile->tlink);
 836         rc = find_cifs_entry(xid, tcon, ctx->pos, file, &current_entry,
 837                              &num_to_fill);
 838         if (rc) {
 839                 cifs_dbg(FYI, "fce error %d\n", rc);
 840                 goto rddir2_exit;
 841         } else if (current_entry != NULL) {
 842                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
 843         } else {
 844                 cifs_dbg(FYI, "could not find entry\n");
 845                 goto rddir2_exit;
 846         }
 847         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
 848                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
 849         max_len = tcon->ses->server->ops->calc_smb_size(
 850                         cifsFile->srch_inf.ntwrk_buf_start);
 851         end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
 852
 853         tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
 854         if (tmp_buf == NULL) {
 855                 rc = -ENOMEM;
 856                 goto rddir2_exit;
 857         }
 858
 859         for (i = 0; i < num_to_fill; i++) {
 860                 if (current_entry == NULL) {
 861                         /* evaluate whether this case is an error */
 862                         cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
 863                                  num_to_fill, i);
 864                         break;
 865                 }
 866                 /*
 867                  * if buggy server returns . and .. late do we want to
 868                  * check for that here?
 869                  */
 870                 rc = cifs_filldir(current_entry, file, ctx,
 871                                   tmp_buf, max_len);
 872                 if (rc) {
 873                         if (rc > 0)
 874                                 rc = 0;
 875                         break;
 876                 }
 877
 878                 ctx->pos++;
 879                 if (ctx->pos ==
 880                         cifsFile->srch_inf.index_of_last_entry) {
 881                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
 882                                  ctx->pos, tmp_buf);
 883                         cifs_save_resume_key(current_entry, cifsFile);
 884                         break;
 885                 } else
 886                         current_entry =
 887                                 nxt_dir_entry(current_entry, end_of_smb,
 888                                         cifsFile->srch_inf.info_level);
 889         }
 890         kfree(tmp_buf);
 891
 892 rddir2_exit:
 893         free_xid(xid);
 894         return rc;
 895 }