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