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 if (fattr->cf_cifsattrs & ATTR_REPARSE) {
 176                 fattr->cf_mode = S_IFLNK;
 177                 fattr->cf_dtype = DT_LNK;
 178         } else {
 179                 fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
 180                 fattr->cf_dtype = DT_REG;
 181         }
 182
 183         /* non-unix readdir doesn't provide nlink */
 184         fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
 185
 186         if (fattr->cf_cifsattrs & ATTR_READONLY)
 187                 fattr->cf_mode &= ~S_IWUGO;
 188
 189         /*
 190          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
 191          * mark it for revalidation so that "ls -l" will look right. It might
 192          * be super-slow, but if we don't do this then the ownership of files
 193          * may look wrong since the inodes may not have timed out by the time
 194          * "ls" does a stat() call on them.
 195          */
 196         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL)
 197                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 198
 199         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
 200             fattr->cf_cifsattrs & ATTR_SYSTEM) {
 201                 if (fattr->cf_eof == 0)  {
 202                         fattr->cf_mode &= ~S_IFMT;
 203                         fattr->cf_mode |= S_IFIFO;
 204                         fattr->cf_dtype = DT_FIFO;
 205                 } else {
 206                         /*
 207                          * trying to get the type and mode via SFU can be slow,
 208                          * so just call those regular files for now, and mark
 209                          * for reval
 210                          */
 211                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 212                 }
 213         }
 214 }
 215
 216 void
 217 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
 218                        struct cifs_sb_info *cifs_sb)
 219 {
 220         memset(fattr, 0, sizeof(*fattr));
 221         fattr->cf_cifsattrs = le32_to_cpu(info->ExtFileAttributes);
 222         fattr->cf_eof = le64_to_cpu(info->EndOfFile);
 223         fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
 224         fattr->cf_createtime = le64_to_cpu(info->CreationTime);
 225         fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
 226         fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
 227         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
 228
 229         cifs_fill_common_info(fattr, cifs_sb);
 230 }
 231
 232 static void
 233 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 234                        struct cifs_sb_info *cifs_sb)
 235 {
 236         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 237
 238         memset(fattr, 0, sizeof(*fattr));
 239         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
 240                                             info->LastAccessTime, offset);
 241         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
 242                                             info->LastWriteTime, offset);
 243         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
 244                                             info->LastWriteTime, offset);
 245
 246         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
 247         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
 248         fattr->cf_eof = le32_to_cpu(info->DataSize);
 249
 250         cifs_fill_common_info(fattr, cifs_sb);
 251 }
 252
 253 /* BB eventually need to add the following helper function to
 254       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
 255       we try to do FindFirst on (NTFS) directory symlinks */
 256 /*
 257 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 258                              unsigned int xid)
 259 {
 260         __u16 fid;
 261         int len;
 262         int oplock = 0;
 263         int rc;
 264         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
 265         char *tmpbuffer;
 266
 267         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
 268                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 269                         cifs_sb->local_nls,
 270                         cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
 271         if (!rc) {
 272                 tmpbuffer = kmalloc(maxpath);
 273                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
 274                                 tmpbuffer,
 275                                 maxpath -1,
 276                                 fid,
 277                                 cifs_sb->local_nls);
 278                 if (CIFSSMBClose(xid, ptcon, fid)) {
 279                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
 280                 }
 281         }
 282 }
 283  */
 284
 285 static int
 286 initiate_cifs_search(const unsigned int xid, struct file *file)
 287 {
 288         __u16 search_flags;
 289         int rc = 0;
 290         char *full_path = NULL;
 291         struct cifsFileInfo *cifsFile;
 292         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 293         struct tcon_link *tlink = NULL;
 294         struct cifs_tcon *tcon;
 295         struct TCP_Server_Info *server;
 296
 297         if (file->private_data == NULL) {
 298                 tlink = cifs_sb_tlink(cifs_sb);
 299                 if (IS_ERR(tlink))
 300                         return PTR_ERR(tlink);
 301
 302                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 303                 if (cifsFile == NULL) {
 304                         rc = -ENOMEM;
 305                         goto error_exit;
 306                 }
 307                 file->private_data = cifsFile;
 308                 cifsFile->tlink = cifs_get_tlink(tlink);
 309                 tcon = tlink_tcon(tlink);
 310         } else {
 311                 cifsFile = file->private_data;
 312                 tcon = tlink_tcon(cifsFile->tlink);
 313         }
 314
 315         server = tcon->ses->server;
 316
 317         if (!server->ops->query_dir_first) {
 318                 rc = -ENOSYS;
 319                 goto error_exit;
 320         }
 321
 322         cifsFile->invalidHandle = true;
 323         cifsFile->srch_inf.endOfSearch = false;
 324
 325         full_path = build_path_from_dentry(file->f_path.dentry);
 326         if (full_path == NULL) {
 327                 rc = -ENOMEM;
 328                 goto error_exit;
 329         }
 330
 331         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 332
 333 ffirst_retry:
 334         /* test for Unix extensions */
 335         /* but now check for them on the share/mount not on the SMB session */
 336         /* if (cap_unix(tcon->ses) { */
 337         if (tcon->unix_ext)
 338                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 339         else if ((tcon->ses->capabilities &
 340                   tcon->ses->server->vals->cap_nt_find) == 0) {
 341                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 342         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 343                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 344         } else /* not srvinos - BB fixme add check for backlevel? */ {
 345                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 346         }
 347
 348         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 349         if (backup_cred(cifs_sb))
 350                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 351
 352         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 353                                           &cifsFile->fid, search_flags,
 354                                           &cifsFile->srch_inf);
 355
 356         if (rc == 0)
 357                 cifsFile->invalidHandle = false;
 358         /* BB add following call to handle readdir on new NTFS symlink errors
 359         else if STATUS_STOPPED_ON_SYMLINK
 360                 call get_symlink_reparse_path and retry with new path */
 361         else if ((rc == -EOPNOTSUPP) &&
 362                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 363                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 364                 goto ffirst_retry;
 365         }
 366 error_exit:
 367         kfree(full_path);
 368         cifs_put_tlink(tlink);
 369         return rc;
 370 }
 371
 372 /* return length of unicode string in bytes */
 373 static int cifs_unicode_bytelen(const char *str)
 374 {
 375         int len;
 376         const __le16 *ustr = (const __le16 *)str;
 377
 378         for (len = 0; len <= PATH_MAX; len++) {
 379                 if (ustr[len] == 0)
 380                         return len << 1;
 381         }
 382         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 383         return len << 1;
 384 }
 385
 386 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 387 {
 388         char *new_entry;
 389         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 390
 391         if (level == SMB_FIND_FILE_INFO_STANDARD) {
 392                 FIND_FILE_STANDARD_INFO *pfData;
 393                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 394
 395                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
 396                                 pfData->FileNameLength;
 397         } else
 398                 new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset);
 399         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 400         /* validate that new_entry is not past end of SMB */
 401         if (new_entry >= end_of_smb) {
 402                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 403                          new_entry, end_of_smb, old_entry);
 404                 return NULL;
 405         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 406                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
 407                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 408                    (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
 409                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 410                          new_entry, end_of_smb);
 411                 return NULL;
 412         } else
 413                 return new_entry;
 414
 415 }
 416
 417 struct cifs_dirent {
 418         const char      *name;
 419         size_t          namelen;
 420         u32             resume_key;
 421         u64             ino;
 422 };
 423
 424 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 425                 const FILE_UNIX_INFO *info, bool is_unicode)
 426 {
 427         de->name = &info->FileName[0];
 428         if (is_unicode)
 429                 de->namelen = cifs_unicode_bytelen(de->name);
 430         else
 431                 de->namelen = strnlen(de->name, PATH_MAX);
 432         de->resume_key = info->ResumeKey;
 433         de->ino = le64_to_cpu(info->basic.UniqueId);
 434 }
 435
 436 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 437                 const FILE_DIRECTORY_INFO *info)
 438 {
 439         de->name = &info->FileName[0];
 440         de->namelen = le32_to_cpu(info->FileNameLength);
 441         de->resume_key = info->FileIndex;
 442 }
 443
 444 static void cifs_fill_dirent_full(struct cifs_dirent *de,
 445                 const FILE_FULL_DIRECTORY_INFO *info)
 446 {
 447         de->name = &info->FileName[0];
 448         de->namelen = le32_to_cpu(info->FileNameLength);
 449         de->resume_key = info->FileIndex;
 450 }
 451
 452 static void cifs_fill_dirent_search(struct cifs_dirent *de,
 453                 const SEARCH_ID_FULL_DIR_INFO *info)
 454 {
 455         de->name = &info->FileName[0];
 456         de->namelen = le32_to_cpu(info->FileNameLength);
 457         de->resume_key = info->FileIndex;
 458         de->ino = le64_to_cpu(info->UniqueId);
 459 }
 460
 461 static void cifs_fill_dirent_both(struct cifs_dirent *de,
 462                 const FILE_BOTH_DIRECTORY_INFO *info)
 463 {
 464         de->name = &info->FileName[0];
 465         de->namelen = le32_to_cpu(info->FileNameLength);
 466         de->resume_key = info->FileIndex;
 467 }
 468
 469 static void cifs_fill_dirent_std(struct cifs_dirent *de,
 470                 const FIND_FILE_STANDARD_INFO *info)
 471 {
 472         de->name = &info->FileName[0];
 473         /* one byte length, no endianess conversion */
 474         de->namelen = info->FileNameLength;
 475         de->resume_key = info->ResumeKey;
 476 }
 477
 478 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 479                 u16 level, bool is_unicode)
 480 {
 481         memset(de, 0, sizeof(*de));
 482
 483         switch (level) {
 484         case SMB_FIND_FILE_UNIX:
 485                 cifs_fill_dirent_unix(de, info, is_unicode);
 486                 break;
 487         case SMB_FIND_FILE_DIRECTORY_INFO:
 488                 cifs_fill_dirent_dir(de, info);
 489                 break;
 490         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 491                 cifs_fill_dirent_full(de, info);
 492                 break;
 493         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 494                 cifs_fill_dirent_search(de, info);
 495                 break;
 496         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 497                 cifs_fill_dirent_both(de, info);
 498                 break;
 499         case SMB_FIND_FILE_INFO_STANDARD:
 500                 cifs_fill_dirent_std(de, info);
 501                 break;
 502         default:
 503                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 504                 return -EINVAL;
 505         }
 506
 507         return 0;
 508 }
 509
 510 #define UNICODE_DOT cpu_to_le16(0x2e)
 511
 512 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 513 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 514 {
 515         int rc = 0;
 516
 517         if (!de->name)
 518                 return 0;
 519
 520         if (is_unicode) {
 521                 __le16 *ufilename = (__le16 *)de->name;
 522                 if (de->namelen == 2) {
 523                         /* check for . */
 524                         if (ufilename[0] == UNICODE_DOT)
 525                                 rc = 1;
 526                 } else if (de->namelen == 4) {
 527                         /* check for .. */
 528                         if (ufilename[0] == UNICODE_DOT &&
 529                             ufilename[1] == UNICODE_DOT)
 530                                 rc = 2;
 531                 }
 532         } else /* ASCII */ {
 533                 if (de->namelen == 1) {
 534                         if (de->name[0] == '.')
 535                                 rc = 1;
 536                 } else if (de->namelen == 2) {
 537                         if (de->name[0] == '.' && de->name[1] == '.')
 538                                 rc = 2;
 539                 }
 540         }
 541
 542         return rc;
 543 }
 544
 545 /* Check if directory that we are searching has changed so we can decide
 546    whether we can use the cached search results from the previous search */
 547 static int is_dir_changed(struct file *file)
 548 {
 549         struct inode *inode = file_inode(file);
 550         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 551
 552         if (cifsInfo->time == 0)
 553                 return 1; /* directory was changed, perhaps due to unlink */
 554         else
 555                 return 0;
 556
 557 }
 558
 559 static int cifs_save_resume_key(const char *current_entry,
 560         struct cifsFileInfo *file_info)
 561 {
 562         struct cifs_dirent de;
 563         int rc;
 564
 565         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 566                               file_info->srch_inf.unicode);
 567         if (!rc) {
 568                 file_info->srch_inf.presume_name = de.name;
 569                 file_info->srch_inf.resume_name_len = de.namelen;
 570                 file_info->srch_inf.resume_key = de.resume_key;
 571         }
 572         return rc;
 573 }
 574
 575 /*
 576  * Find the corresponding entry in the search. Note that the SMB server returns
 577  * search entries for . and .. which complicates logic here if we choose to
 578  * parse for them and we do not assume that they are located in the findfirst
 579  * return buffer. We start counting in the buffer with entry 2 and increment for
 580  * every entry (do not increment for . or .. entry).
 581  */
 582 static int
 583 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
 584                 struct file *file, char **current_entry, int *num_to_ret)
 585 {
 586         __u16 search_flags;
 587         int rc = 0;
 588         int pos_in_buf = 0;
 589         loff_t first_entry_in_buffer;
 590         loff_t index_to_find = pos;
 591         struct cifsFileInfo *cfile = file->private_data;
 592         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 593         struct TCP_Server_Info *server = tcon->ses->server;
 594         /* check if index in the buffer */
 595
 596         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 597                 return -ENOSYS;
 598
 599         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 600                 return -ENOENT;
 601
 602         *current_entry = NULL;
 603         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 604                                         cfile->srch_inf.entries_in_buffer;
 605
 606         /*
 607          * If first entry in buf is zero then is first buffer
 608          * in search response data which means it is likely . and ..
 609          * will be in this buffer, although some servers do not return
 610          * . and .. for the root of a drive and for those we need
 611          * to start two entries earlier.
 612          */
 613
 614         dump_cifs_file_struct(file, "In fce ");
 615         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 616              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 617                 /* close and restart search */
 618                 cifs_dbg(FYI, "search backing up - close and restart search\n");
 619                 spin_lock(&cifs_file_list_lock);
 620                 if (!cfile->srch_inf.endOfSearch && !cfile->invalidHandle) {
 621                         cfile->invalidHandle = true;
 622                         spin_unlock(&cifs_file_list_lock);
 623                         if (server->ops->close)
 624                                 server->ops->close(xid, tcon, &cfile->fid);
 625                 } else
 626                         spin_unlock(&cifs_file_list_lock);
 627                 if (cfile->srch_inf.ntwrk_buf_start) {
 628                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 629                         if (cfile->srch_inf.smallBuf)
 630                                 cifs_small_buf_release(cfile->srch_inf.
 631                                                 ntwrk_buf_start);
 632                         else
 633                                 cifs_buf_release(cfile->srch_inf.
 634                                                 ntwrk_buf_start);
 635                         cfile->srch_inf.ntwrk_buf_start = NULL;
 636                 }
 637                 rc = initiate_cifs_search(xid, file);
 638                 if (rc) {
 639                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 640                                  rc);
 641                         return rc;
 642                 }
 643                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 644                 if (cfile->srch_inf.last_entry)
 645                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 646         }
 647
 648         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 649         if (backup_cred(cifs_sb))
 650                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 651
 652         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 653                (rc == 0) && !cfile->srch_inf.endOfSearch) {
 654                 cifs_dbg(FYI, "calling findnext2\n");
 655                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 656                                                  search_flags,
 657                                                  &cfile->srch_inf);
 658                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 659                 if (cfile->srch_inf.last_entry)
 660                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 661                 if (rc)
 662                         return -ENOENT;
 663         }
 664         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 665                 /* we found the buffer that contains the entry */
 666                 /* scan and find it */
 667                 int i;
 668                 char *cur_ent;
 669                 char *end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 670                         server->ops->calc_smb_size(
 671                                         cfile->srch_inf.ntwrk_buf_start);
 672
 673                 cur_ent = cfile->srch_inf.srch_entries_start;
 674                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 675                                         - cfile->srch_inf.entries_in_buffer;
 676                 pos_in_buf = index_to_find - first_entry_in_buffer;
 677                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 678
 679                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 680                         /* go entry by entry figuring out which is first */
 681                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 682                                                 cfile->srch_inf.info_level);
 683                 }
 684                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
 685                         /* BB fixme - check if we should flag this error */
 686                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 687                                  pos_in_buf, index_to_find, rc);
 688                 }
 689                 rc = 0;
 690                 *current_entry = cur_ent;
 691         } else {
 692                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 693                 return 0;
 694         }
 695
 696         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 697                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 698                 *num_to_ret = 0;
 699         } else
 700                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 701
 702         return rc;
 703 }
 704
 705 static int cifs_filldir(char *find_entry, struct file *file,
 706                 struct dir_context *ctx,
 707                 char *scratch_buf, unsigned int max_len)
 708 {
 709         struct cifsFileInfo *file_info = file->private_data;
 710         struct super_block *sb = file->f_path.dentry->d_sb;
 711         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 712         struct cifs_dirent de = { NULL, };
 713         struct cifs_fattr fattr;
 714         struct qstr name;
 715         int rc = 0;
 716         ino_t ino;
 717
 718         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 719                               file_info->srch_inf.unicode);
 720         if (rc)
 721                 return rc;
 722
 723         if (de.namelen > max_len) {
 724                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 725                          de.namelen);
 726                 return -EINVAL;
 727         }
 728
 729         /* skip . and .. since we added them first */
 730         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 731                 return 0;
 732
 733         if (file_info->srch_inf.unicode) {
 734                 struct nls_table *nlt = cifs_sb->local_nls;
 735
 736                 name.name = scratch_buf;
 737                 name.len =
 738                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 739                                         UNICODE_NAME_MAX,
 740                                         min_t(size_t, de.namelen,
 741                                               (size_t)max_len), nlt,
 742                                         cifs_sb->mnt_cifs_flags &
 743                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 744                 name.len -= nls_nullsize(nlt);
 745         } else {
 746                 name.name = de.name;
 747                 name.len = de.namelen;
 748         }
 749
 750         switch (file_info->srch_inf.info_level) {
 751         case SMB_FIND_FILE_UNIX:
 752                 cifs_unix_basic_to_fattr(&fattr,
 753                                          &((FILE_UNIX_INFO *)find_entry)->basic,
 754                                          cifs_sb);
 755                 break;
 756         case SMB_FIND_FILE_INFO_STANDARD:
 757                 cifs_std_info_to_fattr(&fattr,
 758                                        (FIND_FILE_STANDARD_INFO *)find_entry,
 759                                        cifs_sb);
 760                 break;
 761         default:
 762                 cifs_dir_info_to_fattr(&fattr,
 763                                        (FILE_DIRECTORY_INFO *)find_entry,
 764                                        cifs_sb);
 765                 break;
 766         }
 767
 768         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 769                 fattr.cf_uniqueid = de.ino;
 770         } else {
 771                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
 772                 cifs_autodisable_serverino(cifs_sb);
 773         }
 774
 775         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
 776             CIFSCouldBeMFSymlink(&fattr))
 777                 /*
 778                  * trying to get the type and mode can be slow,
 779                  * so just call those regular files for now, and mark
 780                  * for reval
 781                  */
 782                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
 783
 784         cifs_prime_dcache(file->f_dentry, &name, &fattr);
 785
 786         ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
 787         return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
 788 }
 789
 790
 791 int cifs_readdir(struct file *file, struct dir_context *ctx)
 792 {
 793         int rc = 0;
 794         unsigned int xid;
 795         int i;
 796         struct cifs_tcon *tcon;
 797         struct cifsFileInfo *cifsFile = NULL;
 798         char *current_entry;
 799         int num_to_fill = 0;
 800         char *tmp_buf = NULL;
 801         char *end_of_smb;
 802         unsigned int max_len;
 803
 804         xid = get_xid();
 805
 806         /*
 807          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
 808          * '..'. Otherwise we won't be able to notify VFS in case of failure.
 809          */
 810         if (file->private_data == NULL) {
 811                 rc = initiate_cifs_search(xid, file);
 812                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
 813                 if (rc)
 814                         goto rddir2_exit;
 815         }
 816
 817         if (!dir_emit_dots(file, ctx))
 818                 goto rddir2_exit;
 819
 820         /* 1) If search is active,
 821                 is in current search buffer?
 822                 if it before then restart search
 823                 if after then keep searching till find it */
 824
 825         if (file->private_data == NULL) {
 826                 rc = -EINVAL;
 827                 goto rddir2_exit;
 828         }
 829         cifsFile = file->private_data;
 830         if (cifsFile->srch_inf.endOfSearch) {
 831                 if (cifsFile->srch_inf.emptyDir) {
 832                         cifs_dbg(FYI, "End of search, empty dir\n");
 833                         rc = 0;
 834                         goto rddir2_exit;
 835                 }
 836         } /* else {
 837                 cifsFile->invalidHandle = true;
 838                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
 839         } */
 840
 841         tcon = tlink_tcon(cifsFile->tlink);
 842         rc = find_cifs_entry(xid, tcon, ctx->pos, file, &current_entry,
 843                              &num_to_fill);
 844         if (rc) {
 845                 cifs_dbg(FYI, "fce error %d\n", rc);
 846                 goto rddir2_exit;
 847         } else if (current_entry != NULL) {
 848                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
 849         } else {
 850                 cifs_dbg(FYI, "could not find entry\n");
 851                 goto rddir2_exit;
 852         }
 853         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
 854                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
 855         max_len = tcon->ses->server->ops->calc_smb_size(
 856                         cifsFile->srch_inf.ntwrk_buf_start);
 857         end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
 858
 859         tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
 860         if (tmp_buf == NULL) {
 861                 rc = -ENOMEM;
 862                 goto rddir2_exit;
 863         }
 864
 865         for (i = 0; i < num_to_fill; i++) {
 866                 if (current_entry == NULL) {
 867                         /* evaluate whether this case is an error */
 868                         cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
 869                                  num_to_fill, i);
 870                         break;
 871                 }
 872                 /*
 873                  * if buggy server returns . and .. late do we want to
 874                  * check for that here?
 875                  */
 876                 rc = cifs_filldir(current_entry, file, ctx,
 877                                   tmp_buf, max_len);
 878                 if (rc) {
 879                         if (rc > 0)
 880                                 rc = 0;
 881                         break;
 882                 }
 883
 884                 ctx->pos++;
 885                 if (ctx->pos ==
 886                         cifsFile->srch_inf.index_of_last_entry) {
 887                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
 888                                  ctx->pos, tmp_buf);
 889                         cifs_save_resume_key(current_entry, cifsFile);
 890                         break;
 891                 } else
 892                         current_entry =
 893                                 nxt_dir_entry(current_entry, end_of_smb,
 894                                         cifsFile->srch_inf.info_level);
 895         }
 896         kfree(tmp_buf);
 897
 898 rddir2_exit:
 899         free_xid(xid);
 900         return rc;
 901 }