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 = parent->d_sb;
  82         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
  83         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
  84
  85         cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
  86
  87         dentry = d_hash_and_lookup(parent, name);
  88         if (!dentry) {
  89                 /*
  90                  * If we know that the inode will need to be revalidated
  91                  * immediately, then don't create a new dentry for it.
  92                  * We'll end up doing an on the wire call either way and
  93                  * this spares us an invalidation.
  94                  */
  95                 if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
  96                         return;
  97 retry:
  98                 dentry = d_alloc_parallel(parent, name, &wq);
  99         }
 100         if (IS_ERR(dentry))
 101                 return;
 102         if (!d_in_lookup(dentry)) {
 103                 inode = d_inode(dentry);
 104                 if (inode) {
 105                         if (d_mountpoint(dentry)) {
 106                                 dput(dentry);
 107                                 return;
 108                         }
 109                         /*
 110                          * If we're generating inode numbers, then we don't
 111                          * want to clobber the existing one with the one that
 112                          * the readdir code created.
 113                          */
 114                         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
 115                                 fattr->cf_uniqueid = CIFS_I(inode)->uniqueid;
 116
 117                         /* update inode in place
 118                          * if both i_ino and i_mode didn't change */
 119                         if (CIFS_I(inode)->uniqueid == fattr->cf_uniqueid &&
 120                             (inode->i_mode & S_IFMT) ==
 121                             (fattr->cf_mode & S_IFMT)) {
 122                                 cifs_fattr_to_inode(inode, fattr);
 123                                 dput(dentry);
 124                                 return;
 125                         }
 126                 }
 127                 d_invalidate(dentry);
 128                 dput(dentry);
 129                 goto retry;
 130         } else {
 131                 inode = cifs_iget(sb, fattr);
 132                 if (!inode)
 133                         inode = ERR_PTR(-ENOMEM);
 134                 alias = d_splice_alias(inode, dentry);
 135                 d_lookup_done(dentry);
 136                 if (alias && !IS_ERR(alias))
 137                         dput(alias);
 138         }
 139         dput(dentry);
 140 }
 141
 142 static void
 143 cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
 144 {
 145         fattr->cf_uid = cifs_sb->mnt_uid;
 146         fattr->cf_gid = cifs_sb->mnt_gid;
 147
 148         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 149                 fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
 150                 fattr->cf_dtype = DT_DIR;
 151         } else {
 152                 fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
 153                 fattr->cf_dtype = DT_REG;
 154         }
 155
 156         /*
 157          * We need to revalidate it further to make a decision about whether it
 158          * is a symbolic link, DFS referral or a reparse point with a direct
 159          * access like junctions, deduplicated files, NFS symlinks.
 160          */
 161         if (fattr->cf_cifsattrs & ATTR_REPARSE)
 162                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 163
 164         /* non-unix readdir doesn't provide nlink */
 165         fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
 166
 167         if (fattr->cf_cifsattrs & ATTR_READONLY)
 168                 fattr->cf_mode &= ~S_IWUGO;
 169
 170         /*
 171          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
 172          * mark it for revalidation so that "ls -l" will look right. It might
 173          * be super-slow, but if we don't do this then the ownership of files
 174          * may look wrong since the inodes may not have timed out by the time
 175          * "ls" does a stat() call on them.
 176          */
 177         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL)
 178                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 179
 180         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
 181             fattr->cf_cifsattrs & ATTR_SYSTEM) {
 182                 if (fattr->cf_eof == 0)  {
 183                         fattr->cf_mode &= ~S_IFMT;
 184                         fattr->cf_mode |= S_IFIFO;
 185                         fattr->cf_dtype = DT_FIFO;
 186                 } else {
 187                         /*
 188                          * trying to get the type and mode via SFU can be slow,
 189                          * so just call those regular files for now, and mark
 190                          * for reval
 191                          */
 192                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 193                 }
 194         }
 195 }
 196
 197 void
 198 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
 199                        struct cifs_sb_info *cifs_sb)
 200 {
 201         memset(fattr, 0, sizeof(*fattr));
 202         fattr->cf_cifsattrs = le32_to_cpu(info->ExtFileAttributes);
 203         fattr->cf_eof = le64_to_cpu(info->EndOfFile);
 204         fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
 205         fattr->cf_createtime = le64_to_cpu(info->CreationTime);
 206         fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
 207         fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
 208         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
 209
 210         cifs_fill_common_info(fattr, cifs_sb);
 211 }
 212
 213 static void
 214 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 215                        struct cifs_sb_info *cifs_sb)
 216 {
 217         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 218
 219         memset(fattr, 0, sizeof(*fattr));
 220         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
 221                                             info->LastAccessTime, offset);
 222         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
 223                                             info->LastWriteTime, offset);
 224         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
 225                                             info->LastWriteTime, offset);
 226
 227         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
 228         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
 229         fattr->cf_eof = le32_to_cpu(info->DataSize);
 230
 231         cifs_fill_common_info(fattr, cifs_sb);
 232 }
 233
 234 /* BB eventually need to add the following helper function to
 235       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
 236       we try to do FindFirst on (NTFS) directory symlinks */
 237 /*
 238 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 239                              unsigned int xid)
 240 {
 241         __u16 fid;
 242         int len;
 243         int oplock = 0;
 244         int rc;
 245         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
 246         char *tmpbuffer;
 247
 248         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
 249                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 250                         cifs_sb->local_nls,
 251                         cifs_remap(cifs_sb);
 252         if (!rc) {
 253                 tmpbuffer = kmalloc(maxpath);
 254                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
 255                                 tmpbuffer,
 256                                 maxpath -1,
 257                                 fid,
 258                                 cifs_sb->local_nls);
 259                 if (CIFSSMBClose(xid, ptcon, fid)) {
 260                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
 261                 }
 262         }
 263 }
 264  */
 265
 266 static int
 267 initiate_cifs_search(const unsigned int xid, struct file *file)
 268 {
 269         __u16 search_flags;
 270         int rc = 0;
 271         char *full_path = NULL;
 272         struct cifsFileInfo *cifsFile;
 273         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 274         struct tcon_link *tlink = NULL;
 275         struct cifs_tcon *tcon;
 276         struct TCP_Server_Info *server;
 277
 278         if (file->private_data == NULL) {
 279                 tlink = cifs_sb_tlink(cifs_sb);
 280                 if (IS_ERR(tlink))
 281                         return PTR_ERR(tlink);
 282
 283                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 284                 if (cifsFile == NULL) {
 285                         rc = -ENOMEM;
 286                         goto error_exit;
 287                 }
 288                 spin_lock_init(&cifsFile->file_info_lock);
 289                 file->private_data = cifsFile;
 290                 cifsFile->tlink = cifs_get_tlink(tlink);
 291                 tcon = tlink_tcon(tlink);
 292         } else {
 293                 cifsFile = file->private_data;
 294                 tcon = tlink_tcon(cifsFile->tlink);
 295         }
 296
 297         server = tcon->ses->server;
 298
 299         if (!server->ops->query_dir_first) {
 300                 rc = -ENOSYS;
 301                 goto error_exit;
 302         }
 303
 304         cifsFile->invalidHandle = true;
 305         cifsFile->srch_inf.endOfSearch = false;
 306
 307         full_path = build_path_from_dentry(file_dentry(file));
 308         if (full_path == NULL) {
 309                 rc = -ENOMEM;
 310                 goto error_exit;
 311         }
 312
 313         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 314
 315 ffirst_retry:
 316         /* test for Unix extensions */
 317         /* but now check for them on the share/mount not on the SMB session */
 318         /* if (cap_unix(tcon->ses) { */
 319         if (tcon->unix_ext)
 320                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 321         else if ((tcon->ses->capabilities &
 322                   tcon->ses->server->vals->cap_nt_find) == 0) {
 323                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 324         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 325                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 326         } else /* not srvinos - BB fixme add check for backlevel? */ {
 327                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 328         }
 329
 330         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 331         if (backup_cred(cifs_sb))
 332                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 333
 334         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 335                                           &cifsFile->fid, search_flags,
 336                                           &cifsFile->srch_inf);
 337
 338         if (rc == 0)
 339                 cifsFile->invalidHandle = false;
 340         /* BB add following call to handle readdir on new NTFS symlink errors
 341         else if STATUS_STOPPED_ON_SYMLINK
 342                 call get_symlink_reparse_path and retry with new path */
 343         else if ((rc == -EOPNOTSUPP) &&
 344                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 345                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 346                 goto ffirst_retry;
 347         }
 348 error_exit:
 349         kfree(full_path);
 350         cifs_put_tlink(tlink);
 351         return rc;
 352 }
 353
 354 /* return length of unicode string in bytes */
 355 static int cifs_unicode_bytelen(const char *str)
 356 {
 357         int len;
 358         const __le16 *ustr = (const __le16 *)str;
 359
 360         for (len = 0; len <= PATH_MAX; len++) {
 361                 if (ustr[len] == 0)
 362                         return len << 1;
 363         }
 364         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 365         return len << 1;
 366 }
 367
 368 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 369 {
 370         char *new_entry;
 371         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 372
 373         if (level == SMB_FIND_FILE_INFO_STANDARD) {
 374                 FIND_FILE_STANDARD_INFO *pfData;
 375                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 376
 377                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
 378                                 pfData->FileNameLength;
 379         } else {
 380                 u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset);
 381
 382                 if (old_entry + next_offset < old_entry) {
 383                         cifs_dbg(VFS, "invalid offset %u\n", next_offset);
 384                         return NULL;
 385                 }
 386                 new_entry = old_entry + next_offset;
 387         }
 388         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 389         /* validate that new_entry is not past end of SMB */
 390         if (new_entry >= end_of_smb) {
 391                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 392                          new_entry, end_of_smb, old_entry);
 393                 return NULL;
 394         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 395                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
 396                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 397                    (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
 398                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 399                          new_entry, end_of_smb);
 400                 return NULL;
 401         } else
 402                 return new_entry;
 403
 404 }
 405
 406 struct cifs_dirent {
 407         const char      *name;
 408         size_t          namelen;
 409         u32             resume_key;
 410         u64             ino;
 411 };
 412
 413 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 414                 const FILE_UNIX_INFO *info, bool is_unicode)
 415 {
 416         de->name = &info->FileName[0];
 417         if (is_unicode)
 418                 de->namelen = cifs_unicode_bytelen(de->name);
 419         else
 420                 de->namelen = strnlen(de->name, PATH_MAX);
 421         de->resume_key = info->ResumeKey;
 422         de->ino = le64_to_cpu(info->basic.UniqueId);
 423 }
 424
 425 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 426                 const FILE_DIRECTORY_INFO *info)
 427 {
 428         de->name = &info->FileName[0];
 429         de->namelen = le32_to_cpu(info->FileNameLength);
 430         de->resume_key = info->FileIndex;
 431 }
 432
 433 static void cifs_fill_dirent_full(struct cifs_dirent *de,
 434                 const FILE_FULL_DIRECTORY_INFO *info)
 435 {
 436         de->name = &info->FileName[0];
 437         de->namelen = le32_to_cpu(info->FileNameLength);
 438         de->resume_key = info->FileIndex;
 439 }
 440
 441 static void cifs_fill_dirent_search(struct cifs_dirent *de,
 442                 const SEARCH_ID_FULL_DIR_INFO *info)
 443 {
 444         de->name = &info->FileName[0];
 445         de->namelen = le32_to_cpu(info->FileNameLength);
 446         de->resume_key = info->FileIndex;
 447         de->ino = le64_to_cpu(info->UniqueId);
 448 }
 449
 450 static void cifs_fill_dirent_both(struct cifs_dirent *de,
 451                 const FILE_BOTH_DIRECTORY_INFO *info)
 452 {
 453         de->name = &info->FileName[0];
 454         de->namelen = le32_to_cpu(info->FileNameLength);
 455         de->resume_key = info->FileIndex;
 456 }
 457
 458 static void cifs_fill_dirent_std(struct cifs_dirent *de,
 459                 const FIND_FILE_STANDARD_INFO *info)
 460 {
 461         de->name = &info->FileName[0];
 462         /* one byte length, no endianess conversion */
 463         de->namelen = info->FileNameLength;
 464         de->resume_key = info->ResumeKey;
 465 }
 466
 467 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 468                 u16 level, bool is_unicode)
 469 {
 470         memset(de, 0, sizeof(*de));
 471
 472         switch (level) {
 473         case SMB_FIND_FILE_UNIX:
 474                 cifs_fill_dirent_unix(de, info, is_unicode);
 475                 break;
 476         case SMB_FIND_FILE_DIRECTORY_INFO:
 477                 cifs_fill_dirent_dir(de, info);
 478                 break;
 479         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 480                 cifs_fill_dirent_full(de, info);
 481                 break;
 482         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 483                 cifs_fill_dirent_search(de, info);
 484                 break;
 485         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 486                 cifs_fill_dirent_both(de, info);
 487                 break;
 488         case SMB_FIND_FILE_INFO_STANDARD:
 489                 cifs_fill_dirent_std(de, info);
 490                 break;
 491         default:
 492                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 493                 return -EINVAL;
 494         }
 495
 496         return 0;
 497 }
 498
 499 #define UNICODE_DOT cpu_to_le16(0x2e)
 500
 501 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 502 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 503 {
 504         int rc = 0;
 505
 506         if (!de->name)
 507                 return 0;
 508
 509         if (is_unicode) {
 510                 __le16 *ufilename = (__le16 *)de->name;
 511                 if (de->namelen == 2) {
 512                         /* check for . */
 513                         if (ufilename[0] == UNICODE_DOT)
 514                                 rc = 1;
 515                 } else if (de->namelen == 4) {
 516                         /* check for .. */
 517                         if (ufilename[0] == UNICODE_DOT &&
 518                             ufilename[1] == UNICODE_DOT)
 519                                 rc = 2;
 520                 }
 521         } else /* ASCII */ {
 522                 if (de->namelen == 1) {
 523                         if (de->name[0] == '.')
 524                                 rc = 1;
 525                 } else if (de->namelen == 2) {
 526                         if (de->name[0] == '.' && de->name[1] == '.')
 527                                 rc = 2;
 528                 }
 529         }
 530
 531         return rc;
 532 }
 533
 534 /* Check if directory that we are searching has changed so we can decide
 535    whether we can use the cached search results from the previous search */
 536 static int is_dir_changed(struct file *file)
 537 {
 538         struct inode *inode = file_inode(file);
 539         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 540
 541         if (cifsInfo->time == 0)
 542                 return 1; /* directory was changed, perhaps due to unlink */
 543         else
 544                 return 0;
 545
 546 }
 547
 548 static int cifs_save_resume_key(const char *current_entry,
 549         struct cifsFileInfo *file_info)
 550 {
 551         struct cifs_dirent de;
 552         int rc;
 553
 554         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 555                               file_info->srch_inf.unicode);
 556         if (!rc) {
 557                 file_info->srch_inf.presume_name = de.name;
 558                 file_info->srch_inf.resume_name_len = de.namelen;
 559                 file_info->srch_inf.resume_key = de.resume_key;
 560         }
 561         return rc;
 562 }
 563
 564 /*
 565  * Find the corresponding entry in the search. Note that the SMB server returns
 566  * search entries for . and .. which complicates logic here if we choose to
 567  * parse for them and we do not assume that they are located in the findfirst
 568  * return buffer. We start counting in the buffer with entry 2 and increment for
 569  * every entry (do not increment for . or .. entry).
 570  */
 571 static int
 572 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
 573                 struct file *file, char **current_entry, int *num_to_ret)
 574 {
 575         __u16 search_flags;
 576         int rc = 0;
 577         int pos_in_buf = 0;
 578         loff_t first_entry_in_buffer;
 579         loff_t index_to_find = pos;
 580         struct cifsFileInfo *cfile = file->private_data;
 581         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 582         struct TCP_Server_Info *server = tcon->ses->server;
 583         /* check if index in the buffer */
 584
 585         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 586                 return -ENOSYS;
 587
 588         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 589                 return -ENOENT;
 590
 591         *current_entry = NULL;
 592         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 593                                         cfile->srch_inf.entries_in_buffer;
 594
 595         /*
 596          * If first entry in buf is zero then is first buffer
 597          * in search response data which means it is likely . and ..
 598          * will be in this buffer, although some servers do not return
 599          * . and .. for the root of a drive and for those we need
 600          * to start two entries earlier.
 601          */
 602
 603         dump_cifs_file_struct(file, "In fce ");
 604         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 605              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 606                 /* close and restart search */
 607                 cifs_dbg(FYI, "search backing up - close and restart search\n");
 608                 spin_lock(&cfile->file_info_lock);
 609                 if (server->ops->dir_needs_close(cfile)) {
 610                         cfile->invalidHandle = true;
 611                         spin_unlock(&cfile->file_info_lock);
 612                         if (server->ops->close_dir)
 613                                 server->ops->close_dir(xid, tcon, &cfile->fid);
 614                 } else
 615                         spin_unlock(&cfile->file_info_lock);
 616                 if (cfile->srch_inf.ntwrk_buf_start) {
 617                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 618                         if (cfile->srch_inf.smallBuf)
 619                                 cifs_small_buf_release(cfile->srch_inf.
 620                                                 ntwrk_buf_start);
 621                         else
 622                                 cifs_buf_release(cfile->srch_inf.
 623                                                 ntwrk_buf_start);
 624                         cfile->srch_inf.ntwrk_buf_start = NULL;
 625                 }
 626                 rc = initiate_cifs_search(xid, file);
 627                 if (rc) {
 628                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 629                                  rc);
 630                         return rc;
 631                 }
 632                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 633                 if (cfile->srch_inf.last_entry)
 634                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 635         }
 636
 637         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 638         if (backup_cred(cifs_sb))
 639                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 640
 641         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 642                (rc == 0) && !cfile->srch_inf.endOfSearch) {
 643                 cifs_dbg(FYI, "calling findnext2\n");
 644                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 645                                                  search_flags,
 646                                                  &cfile->srch_inf);
 647                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 648                 if (cfile->srch_inf.last_entry)
 649                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 650                 if (rc)
 651                         return -ENOENT;
 652         }
 653         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 654                 /* we found the buffer that contains the entry */
 655                 /* scan and find it */
 656                 int i;
 657                 char *cur_ent;
 658                 char *end_of_smb;
 659
 660                 if (cfile->srch_inf.ntwrk_buf_start == NULL) {
 661                         cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n");
 662                         return -EIO;
 663                 }
 664
 665                 end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 666                         server->ops->calc_smb_size(
 667                                         cfile->srch_inf.ntwrk_buf_start,
 668                                         server);
 669
 670                 cur_ent = cfile->srch_inf.srch_entries_start;
 671                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 672                                         - cfile->srch_inf.entries_in_buffer;
 673                 pos_in_buf = index_to_find - first_entry_in_buffer;
 674                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 675
 676                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 677                         /* go entry by entry figuring out which is first */
 678                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 679                                                 cfile->srch_inf.info_level);
 680                 }
 681                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
 682                         /* BB fixme - check if we should flag this error */
 683                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 684                                  pos_in_buf, index_to_find, rc);
 685                 }
 686                 rc = 0;
 687                 *current_entry = cur_ent;
 688         } else {
 689                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 690                 return 0;
 691         }
 692
 693         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 694                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 695                 *num_to_ret = 0;
 696         } else
 697                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 698
 699         return rc;
 700 }
 701
 702 static int cifs_filldir(char *find_entry, struct file *file,
 703                 struct dir_context *ctx,
 704                 char *scratch_buf, unsigned int max_len)
 705 {
 706         struct cifsFileInfo *file_info = file->private_data;
 707         struct super_block *sb = file_inode(file)->i_sb;
 708         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 709         struct cifs_dirent de = { NULL, };
 710         struct cifs_fattr fattr;
 711         struct qstr name;
 712         int rc = 0;
 713         ino_t ino;
 714
 715         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 716                               file_info->srch_inf.unicode);
 717         if (rc)
 718                 return rc;
 719
 720         if (de.namelen > max_len) {
 721                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 722                          de.namelen);
 723                 return -EINVAL;
 724         }
 725
 726         /* skip . and .. since we added them first */
 727         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 728                 return 0;
 729
 730         if (file_info->srch_inf.unicode) {
 731                 struct nls_table *nlt = cifs_sb->local_nls;
 732                 int map_type;
 733
 734                 map_type = cifs_remap(cifs_sb);
 735                 name.name = scratch_buf;
 736                 name.len =
 737                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 738                                         UNICODE_NAME_MAX,
 739                                         min_t(size_t, de.namelen,
 740                                               (size_t)max_len), nlt, map_type);
 741                 name.len -= nls_nullsize(nlt);
 742         } else {
 743                 name.name = de.name;
 744                 name.len = de.namelen;
 745         }
 746
 747         switch (file_info->srch_inf.info_level) {
 748         case SMB_FIND_FILE_UNIX:
 749                 cifs_unix_basic_to_fattr(&fattr,
 750                                          &((FILE_UNIX_INFO *)find_entry)->basic,
 751                                          cifs_sb);
 752                 break;
 753         case SMB_FIND_FILE_INFO_STANDARD:
 754                 cifs_std_info_to_fattr(&fattr,
 755                                        (FIND_FILE_STANDARD_INFO *)find_entry,
 756                                        cifs_sb);
 757                 break;
 758         default:
 759                 cifs_dir_info_to_fattr(&fattr,
 760                                        (FILE_DIRECTORY_INFO *)find_entry,
 761                                        cifs_sb);
 762                 break;
 763         }
 764
 765         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 766                 fattr.cf_uniqueid = de.ino;
 767         } else {
 768                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
 769                 cifs_autodisable_serverino(cifs_sb);
 770         }
 771
 772         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
 773             couldbe_mf_symlink(&fattr))
 774                 /*
 775                  * trying to get the type and mode can be slow,
 776                  * so just call those regular files for now, and mark
 777                  * for reval
 778                  */
 779                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
 780
 781         cifs_prime_dcache(file_dentry(file), &name, &fattr);
 782
 783         ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
 784         return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
 785 }
 786
 787
 788 int cifs_readdir(struct file *file, struct dir_context *ctx)
 789 {
 790         int rc = 0;
 791         unsigned int xid;
 792         int i;
 793         struct cifs_tcon *tcon;
 794         struct cifsFileInfo *cifsFile = NULL;
 795         char *current_entry;
 796         int num_to_fill = 0;
 797         char *tmp_buf = NULL;
 798         char *end_of_smb;
 799         unsigned int max_len;
 800
 801         xid = get_xid();
 802
 803         /*
 804          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
 805          * '..'. Otherwise we won't be able to notify VFS in case of failure.
 806          */
 807         if (file->private_data == NULL) {
 808                 rc = initiate_cifs_search(xid, file);
 809                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
 810                 if (rc)
 811                         goto rddir2_exit;
 812         }
 813
 814         if (!dir_emit_dots(file, ctx))
 815                 goto rddir2_exit;
 816
 817         /* 1) If search is active,
 818                 is in current search buffer?
 819                 if it before then restart search
 820                 if after then keep searching till find it */
 821
 822         cifsFile = file->private_data;
 823         if (cifsFile->srch_inf.endOfSearch) {
 824                 if (cifsFile->srch_inf.emptyDir) {
 825                         cifs_dbg(FYI, "End of search, empty dir\n");
 826                         rc = 0;
 827                         goto rddir2_exit;
 828                 }
 829         } /* else {
 830                 cifsFile->invalidHandle = true;
 831                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
 832         } */
 833
 834         tcon = tlink_tcon(cifsFile->tlink);
 835         rc = find_cifs_entry(xid, tcon, ctx->pos, file, &current_entry,
 836                              &num_to_fill);
 837         if (rc) {
 838                 cifs_dbg(FYI, "fce error %d\n", rc);
 839                 goto rddir2_exit;
 840         } else if (current_entry != NULL) {
 841                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
 842         } else {
 843                 cifs_dbg(FYI, "could not find entry\n");
 844                 goto rddir2_exit;
 845         }
 846         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
 847                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
 848         max_len = tcon->ses->server->ops->calc_smb_size(
 849                         cifsFile->srch_inf.ntwrk_buf_start,
 850                         tcon->ses->server);
 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                 *tmp_buf = 0;
 871                 rc = cifs_filldir(current_entry, file, ctx,
 872                                   tmp_buf, max_len);
 873                 if (rc) {
 874                         if (rc > 0)
 875                                 rc = 0;
 876                         break;
 877                 }
 878
 879                 ctx->pos++;
 880                 if (ctx->pos ==
 881                         cifsFile->srch_inf.index_of_last_entry) {
 882                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
 883                                  ctx->pos, tmp_buf);
 884                         cifs_save_resume_key(current_entry, cifsFile);
 885                         break;
 886                 } else
 887                         current_entry =
 888                                 nxt_dir_entry(current_entry, end_of_smb,
 889                                         cifsFile->srch_inf.info_level);
 890         }
 891         kfree(tmp_buf);
 892
 893 rddir2_exit:
 894         free_xid(xid);
 895         return rc;
 896 }