fs/smb/client/readdir.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 /*
   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 ([email protected])
   9  *
  10  */
  11 #include <linux/fs.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/slab.h>
  14 #include <linux/stat.h>
  15 #include "cifspdu.h"
  16 #include "cifsglob.h"
  17 #include "cifsproto.h"
  18 #include "cifs_unicode.h"
  19 #include "cifs_debug.h"
  20 #include "cifs_fs_sb.h"
  21 #include "cifsfs.h"
  22 #include "smb2proto.h"
  23 #include "fs_context.h"
  24 #include "cached_dir.h"
  25
  26 /*
  27  * To be safe - for UCS to UTF-8 with strings loaded with the rare long
  28  * characters alloc more to account for such multibyte target UTF-8
  29  * characters.
  30  */
  31 #define UNICODE_NAME_MAX ((4 * NAME_MAX) + 2)
  32
  33 #ifdef CONFIG_CIFS_DEBUG2
  34 static void dump_cifs_file_struct(struct file *file, char *label)
  35 {
  36         struct cifsFileInfo *cf;
  37
  38         if (file) {
  39                 cf = file->private_data;
  40                 if (cf == NULL) {
  41                         cifs_dbg(FYI, "empty cifs private file data\n");
  42                         return;
  43                 }
  44                 if (cf->invalidHandle)
  45                         cifs_dbg(FYI, "Invalid handle\n");
  46                 if (cf->srch_inf.endOfSearch)
  47                         cifs_dbg(FYI, "end of search\n");
  48                 if (cf->srch_inf.emptyDir)
  49                         cifs_dbg(FYI, "empty dir\n");
  50         }
  51 }
  52 #else
  53 static inline void dump_cifs_file_struct(struct file *file, char *label)
  54 {
  55 }
  56 #endif /* DEBUG2 */
  57
  58 /*
  59  * Attempt to preload the dcache with the results from the FIND_FIRST/NEXT
  60  *
  61  * Find the dentry that matches "name". If there isn't one, create one. If it's
  62  * a negative dentry or the uniqueid or filetype(mode) changed,
  63  * then drop it and recreate it.
  64  */
  65 static void
  66 cifs_prime_dcache(struct dentry *parent, struct qstr *name,
  67                     struct cifs_fattr *fattr)
  68 {
  69         struct dentry *dentry, *alias;
  70         struct inode *inode;
  71         struct super_block *sb = parent->d_sb;
  72         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
  73         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
  74
  75         cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
  76
  77         dentry = d_hash_and_lookup(parent, name);
  78         if (!dentry) {
  79                 /*
  80                  * If we know that the inode will need to be revalidated
  81                  * immediately, then don't create a new dentry for it.
  82                  * We'll end up doing an on the wire call either way and
  83                  * this spares us an invalidation.
  84                  */
  85                 if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
  86                         return;
  87 retry:
  88                 dentry = d_alloc_parallel(parent, name, &wq);
  89         }
  90         if (IS_ERR(dentry))
  91                 return;
  92         if (!d_in_lookup(dentry)) {
  93                 inode = d_inode(dentry);
  94                 if (inode) {
  95                         if (d_mountpoint(dentry)) {
  96                                 dput(dentry);
  97                                 return;
  98                         }
  99                         /*
 100                          * If we're generating inode numbers, then we don't
 101                          * want to clobber the existing one with the one that
 102                          * the readdir code created.
 103                          */
 104                         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
 105                                 fattr->cf_uniqueid = CIFS_I(inode)->uniqueid;
 106
 107                         /* update inode in place
 108                          * if both i_ino and i_mode didn't change */
 109                         if (CIFS_I(inode)->uniqueid == fattr->cf_uniqueid &&
 110                             cifs_fattr_to_inode(inode, fattr) == 0) {
 111                                 dput(dentry);
 112                                 return;
 113                         }
 114                 }
 115                 d_invalidate(dentry);
 116                 dput(dentry);
 117                 goto retry;
 118         } else {
 119                 inode = cifs_iget(sb, fattr);
 120                 if (!inode)
 121                         inode = ERR_PTR(-ENOMEM);
 122                 alias = d_splice_alias(inode, dentry);
 123                 d_lookup_done(dentry);
 124                 if (alias && !IS_ERR(alias))
 125                         dput(alias);
 126         }
 127         dput(dentry);
 128 }
 129
 130 static bool reparse_file_needs_reval(const struct cifs_fattr *fattr)
 131 {
 132         if (!(fattr->cf_cifsattrs & ATTR_REPARSE))
 133                 return false;
 134         /*
 135          * The DFS tags should be only intepreted by server side as per
 136          * MS-FSCC 2.1.2.1, but let's include them anyway.
 137          *
 138          * Besides, if cf_cifstag is unset (0), then we still need it to be
 139          * revalidated to know exactly what reparse point it is.
 140          */
 141         switch (fattr->cf_cifstag) {
 142         case IO_REPARSE_TAG_DFS:
 143         case IO_REPARSE_TAG_DFSR:
 144         case IO_REPARSE_TAG_SYMLINK:
 145         case IO_REPARSE_TAG_NFS:
 146         case IO_REPARSE_TAG_MOUNT_POINT:
 147         case 0:
 148                 return true;
 149         }
 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->ctx->linux_uid;
 157         fattr->cf_gid = cifs_sb->ctx->linux_gid;
 158
 159         /*
 160          * The IO_REPARSE_TAG_LX_ tags originally were used by WSL but they
 161          * are preferred by the Linux client in some cases since, unlike
 162          * the NFS reparse tag (or EAs), they don't require an extra query
 163          * to determine which type of special file they represent.
 164          * TODO: go through all documented  reparse tags to see if we can
 165          * reasonably map some of them to directories vs. files vs. symlinks
 166          */
 167         if ((fattr->cf_cifsattrs & ATTR_REPARSE) &&
 168             cifs_reparse_point_to_fattr(cifs_sb, fattr, fattr->cf_cifstag))
 169                 goto out_reparse;
 170
 171         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 172                 fattr->cf_mode = S_IFDIR | cifs_sb->ctx->dir_mode;
 173                 fattr->cf_dtype = DT_DIR;
 174         } else {
 175                 fattr->cf_mode = S_IFREG | cifs_sb->ctx->file_mode;
 176                 fattr->cf_dtype = DT_REG;
 177         }
 178
 179 out_reparse:
 180         /*
 181          * We need to revalidate it further to make a decision about whether it
 182          * is a symbolic link, DFS referral or a reparse point with a direct
 183          * access like junctions, deduplicated files, NFS symlinks.
 184          */
 185         if (reparse_file_needs_reval(fattr))
 186                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 187
 188         /* non-unix readdir doesn't provide nlink */
 189         fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
 190
 191         if (fattr->cf_cifsattrs & ATTR_READONLY)
 192                 fattr->cf_mode &= ~S_IWUGO;
 193
 194         /*
 195          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
 196          * mark it for revalidation so that "ls -l" will look right. It might
 197          * be super-slow, but if we don't do this then the ownership of files
 198          * may look wrong since the inodes may not have timed out by the time
 199          * "ls" does a stat() call on them.
 200          */
 201         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) ||
 202             (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID))
 203                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 204
 205         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
 206             fattr->cf_cifsattrs & ATTR_SYSTEM) {
 207                 if (fattr->cf_eof == 0)  {
 208                         fattr->cf_mode &= ~S_IFMT;
 209                         fattr->cf_mode |= S_IFIFO;
 210                         fattr->cf_dtype = DT_FIFO;
 211                 } else {
 212                         /*
 213                          * trying to get the type and mode via SFU can be slow,
 214                          * so just call those regular files for now, and mark
 215                          * for reval
 216                          */
 217                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 218                 }
 219         }
 220 }
 221
 222 /* Fill a cifs_fattr struct with info from SMB_FIND_FILE_POSIX_INFO. */
 223 static void
 224 cifs_posix_to_fattr(struct cifs_fattr *fattr, struct smb2_posix_info *info,
 225                     struct cifs_sb_info *cifs_sb)
 226 {
 227         struct smb2_posix_info_parsed parsed;
 228
 229         posix_info_parse(info, NULL, &parsed);
 230
 231         memset(fattr, 0, sizeof(*fattr));
 232         fattr->cf_uniqueid = le64_to_cpu(info->Inode);
 233         fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
 234         fattr->cf_eof = le64_to_cpu(info->EndOfFile);
 235
 236         fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
 237         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
 238         fattr->cf_ctime = cifs_NTtimeToUnix(info->CreationTime);
 239
 240         fattr->cf_nlink = le32_to_cpu(info->HardLinks);
 241         fattr->cf_cifsattrs = le32_to_cpu(info->DosAttributes);
 242
 243         /*
 244          * Since we set the inode type below we need to mask off
 245          * to avoid strange results if bits set above.
 246          * XXX: why not make server&client use the type bits?
 247          */
 248         fattr->cf_mode = le32_to_cpu(info->Mode) & ~S_IFMT;
 249
 250         cifs_dbg(FYI, "posix fattr: dev %d, reparse %d, mode %o\n",
 251                  le32_to_cpu(info->DeviceId),
 252                  le32_to_cpu(info->ReparseTag),
 253                  le32_to_cpu(info->Mode));
 254
 255         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 256                 fattr->cf_mode |= S_IFDIR;
 257                 fattr->cf_dtype = DT_DIR;
 258         } else {
 259                 /*
 260                  * mark anything that is not a dir as regular
 261                  * file. special files should have the REPARSE
 262                  * attribute and will be marked as needing revaluation
 263                  */
 264                 fattr->cf_mode |= S_IFREG;
 265                 fattr->cf_dtype = DT_REG;
 266         }
 267
 268         if (reparse_file_needs_reval(fattr))
 269                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 270
 271         sid_to_id(cifs_sb, &parsed.owner, fattr, SIDOWNER);
 272         sid_to_id(cifs_sb, &parsed.group, fattr, SIDGROUP);
 273 }
 274
 275 static void __dir_info_to_fattr(struct cifs_fattr *fattr, const void *info)
 276 {
 277         const FILE_DIRECTORY_INFO *fi = info;
 278
 279         memset(fattr, 0, sizeof(*fattr));
 280         fattr->cf_cifsattrs = le32_to_cpu(fi->ExtFileAttributes);
 281         fattr->cf_eof = le64_to_cpu(fi->EndOfFile);
 282         fattr->cf_bytes = le64_to_cpu(fi->AllocationSize);
 283         fattr->cf_createtime = le64_to_cpu(fi->CreationTime);
 284         fattr->cf_atime = cifs_NTtimeToUnix(fi->LastAccessTime);
 285         fattr->cf_ctime = cifs_NTtimeToUnix(fi->ChangeTime);
 286         fattr->cf_mtime = cifs_NTtimeToUnix(fi->LastWriteTime);
 287 }
 288
 289 void
 290 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
 291                        struct cifs_sb_info *cifs_sb)
 292 {
 293         __dir_info_to_fattr(fattr, info);
 294         cifs_fill_common_info(fattr, cifs_sb);
 295 }
 296
 297 static void cifs_fulldir_info_to_fattr(struct cifs_fattr *fattr,
 298                                        SEARCH_ID_FULL_DIR_INFO *info,
 299                                        struct cifs_sb_info *cifs_sb)
 300 {
 301         __dir_info_to_fattr(fattr, info);
 302
 303         /* See MS-FSCC 2.4.19 FileIdFullDirectoryInformation */
 304         if (fattr->cf_cifsattrs & ATTR_REPARSE)
 305                 fattr->cf_cifstag = le32_to_cpu(info->EaSize);
 306         cifs_fill_common_info(fattr, cifs_sb);
 307 }
 308
 309 static void
 310 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 311                        struct cifs_sb_info *cifs_sb)
 312 {
 313         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 314
 315         memset(fattr, 0, sizeof(*fattr));
 316         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
 317                                             info->LastAccessTime, offset);
 318         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
 319                                             info->LastWriteTime, offset);
 320         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
 321                                             info->LastWriteTime, offset);
 322
 323         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
 324         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
 325         fattr->cf_eof = le32_to_cpu(info->DataSize);
 326
 327         cifs_fill_common_info(fattr, cifs_sb);
 328 }
 329
 330 /* BB eventually need to add the following helper function to
 331       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
 332       we try to do FindFirst on (NTFS) directory symlinks */
 333 /*
 334 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 335                              unsigned int xid)
 336 {
 337         __u16 fid;
 338         int len;
 339         int oplock = 0;
 340         int rc;
 341         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
 342         char *tmpbuffer;
 343
 344         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
 345                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 346                         cifs_sb->local_nls,
 347                         cifs_remap(cifs_sb);
 348         if (!rc) {
 349                 tmpbuffer = kmalloc(maxpath);
 350                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
 351                                 tmpbuffer,
 352                                 maxpath -1,
 353                                 fid,
 354                                 cifs_sb->local_nls);
 355                 if (CIFSSMBClose(xid, ptcon, fid)) {
 356                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
 357                 }
 358         }
 359 }
 360  */
 361
 362 static int
 363 _initiate_cifs_search(const unsigned int xid, struct file *file,
 364                      const char *full_path)
 365 {
 366         __u16 search_flags;
 367         int rc = 0;
 368         struct cifsFileInfo *cifsFile;
 369         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 370         struct tcon_link *tlink = NULL;
 371         struct cifs_tcon *tcon;
 372         struct TCP_Server_Info *server;
 373
 374         if (file->private_data == NULL) {
 375                 tlink = cifs_sb_tlink(cifs_sb);
 376                 if (IS_ERR(tlink))
 377                         return PTR_ERR(tlink);
 378
 379                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 380                 if (cifsFile == NULL) {
 381                         rc = -ENOMEM;
 382                         goto error_exit;
 383                 }
 384                 spin_lock_init(&cifsFile->file_info_lock);
 385                 file->private_data = cifsFile;
 386                 cifsFile->tlink = cifs_get_tlink(tlink);
 387                 tcon = tlink_tcon(tlink);
 388         } else {
 389                 cifsFile = file->private_data;
 390                 tcon = tlink_tcon(cifsFile->tlink);
 391         }
 392
 393         server = tcon->ses->server;
 394
 395         if (!server->ops->query_dir_first) {
 396                 rc = -ENOSYS;
 397                 goto error_exit;
 398         }
 399
 400         cifsFile->invalidHandle = true;
 401         cifsFile->srch_inf.endOfSearch = false;
 402
 403         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 404
 405 ffirst_retry:
 406         /* test for Unix extensions */
 407         /* but now check for them on the share/mount not on the SMB session */
 408         /* if (cap_unix(tcon->ses) { */
 409         if (tcon->unix_ext)
 410                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 411         else if (tcon->posix_extensions)
 412                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_POSIX_INFO;
 413         else if ((tcon->ses->capabilities &
 414                   tcon->ses->server->vals->cap_nt_find) == 0) {
 415                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 416         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 417                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 418         } else /* not srvinos - BB fixme add check for backlevel? */ {
 419                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 420         }
 421
 422         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 423         if (backup_cred(cifs_sb))
 424                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 425
 426         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 427                                           &cifsFile->fid, search_flags,
 428                                           &cifsFile->srch_inf);
 429
 430         if (rc == 0)
 431                 cifsFile->invalidHandle = false;
 432         /* BB add following call to handle readdir on new NTFS symlink errors
 433         else if STATUS_STOPPED_ON_SYMLINK
 434                 call get_symlink_reparse_path and retry with new path */
 435         else if ((rc == -EOPNOTSUPP) &&
 436                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 437                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 438                 goto ffirst_retry;
 439         }
 440 error_exit:
 441         cifs_put_tlink(tlink);
 442         return rc;
 443 }
 444
 445 static int
 446 initiate_cifs_search(const unsigned int xid, struct file *file,
 447                      const char *full_path)
 448 {
 449         int rc, retry_count = 0;
 450
 451         do {
 452                 rc = _initiate_cifs_search(xid, file, full_path);
 453                 /*
 454                  * If we don't have enough credits to start reading the
 455                  * directory just try again after short wait.
 456                  */
 457                 if (rc != -EDEADLK)
 458                         break;
 459
 460                 usleep_range(512, 2048);
 461         } while (retry_count++ < 5);
 462
 463         return rc;
 464 }
 465
 466 /* return length of unicode string in bytes */
 467 static int cifs_unicode_bytelen(const char *str)
 468 {
 469         int len;
 470         const __le16 *ustr = (const __le16 *)str;
 471
 472         for (len = 0; len <= PATH_MAX; len++) {
 473                 if (ustr[len] == 0)
 474                         return len << 1;
 475         }
 476         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 477         return len << 1;
 478 }
 479
 480 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 481 {
 482         char *new_entry;
 483         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 484
 485         if (level == SMB_FIND_FILE_INFO_STANDARD) {
 486                 FIND_FILE_STANDARD_INFO *pfData;
 487                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 488
 489                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) + 1 +
 490                                 pfData->FileNameLength;
 491         } else {
 492                 u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset);
 493
 494                 if (old_entry + next_offset < old_entry) {
 495                         cifs_dbg(VFS, "Invalid offset %u\n", next_offset);
 496                         return NULL;
 497                 }
 498                 new_entry = old_entry + next_offset;
 499         }
 500         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 501         /* validate that new_entry is not past end of SMB */
 502         if (new_entry >= end_of_smb) {
 503                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 504                          new_entry, end_of_smb, old_entry);
 505                 return NULL;
 506         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 507                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) + 1 > end_of_smb))
 508                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 509                    (new_entry + sizeof(FILE_DIRECTORY_INFO) + 1 > end_of_smb)))  {
 510                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 511                          new_entry, end_of_smb);
 512                 return NULL;
 513         } else
 514                 return new_entry;
 515
 516 }
 517
 518 struct cifs_dirent {
 519         const char      *name;
 520         size_t          namelen;
 521         u32             resume_key;
 522         u64             ino;
 523 };
 524
 525 static void cifs_fill_dirent_posix(struct cifs_dirent *de,
 526                                    const struct smb2_posix_info *info)
 527 {
 528         struct smb2_posix_info_parsed parsed;
 529
 530         /* payload should have already been checked at this point */
 531         if (posix_info_parse(info, NULL, &parsed) < 0) {
 532                 cifs_dbg(VFS, "Invalid POSIX info payload\n");
 533                 return;
 534         }
 535
 536         de->name = parsed.name;
 537         de->namelen = parsed.name_len;
 538         de->resume_key = info->Ignored;
 539         de->ino = le64_to_cpu(info->Inode);
 540 }
 541
 542 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 543                 const FILE_UNIX_INFO *info, bool is_unicode)
 544 {
 545         de->name = &info->FileName[0];
 546         if (is_unicode)
 547                 de->namelen = cifs_unicode_bytelen(de->name);
 548         else
 549                 de->namelen = strnlen(de->name, PATH_MAX);
 550         de->resume_key = info->ResumeKey;
 551         de->ino = le64_to_cpu(info->basic.UniqueId);
 552 }
 553
 554 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 555                 const FILE_DIRECTORY_INFO *info)
 556 {
 557         de->name = &info->FileName[0];
 558         de->namelen = le32_to_cpu(info->FileNameLength);
 559         de->resume_key = info->FileIndex;
 560 }
 561
 562 static void cifs_fill_dirent_full(struct cifs_dirent *de,
 563                 const FILE_FULL_DIRECTORY_INFO *info)
 564 {
 565         de->name = &info->FileName[0];
 566         de->namelen = le32_to_cpu(info->FileNameLength);
 567         de->resume_key = info->FileIndex;
 568 }
 569
 570 static void cifs_fill_dirent_search(struct cifs_dirent *de,
 571                 const SEARCH_ID_FULL_DIR_INFO *info)
 572 {
 573         de->name = &info->FileName[0];
 574         de->namelen = le32_to_cpu(info->FileNameLength);
 575         de->resume_key = info->FileIndex;
 576         de->ino = le64_to_cpu(info->UniqueId);
 577 }
 578
 579 static void cifs_fill_dirent_both(struct cifs_dirent *de,
 580                 const FILE_BOTH_DIRECTORY_INFO *info)
 581 {
 582         de->name = &info->FileName[0];
 583         de->namelen = le32_to_cpu(info->FileNameLength);
 584         de->resume_key = info->FileIndex;
 585 }
 586
 587 static void cifs_fill_dirent_std(struct cifs_dirent *de,
 588                 const FIND_FILE_STANDARD_INFO *info)
 589 {
 590         de->name = &info->FileName[0];
 591         /* one byte length, no endianess conversion */
 592         de->namelen = info->FileNameLength;
 593         de->resume_key = info->ResumeKey;
 594 }
 595
 596 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 597                 u16 level, bool is_unicode)
 598 {
 599         memset(de, 0, sizeof(*de));
 600
 601         switch (level) {
 602         case SMB_FIND_FILE_POSIX_INFO:
 603                 cifs_fill_dirent_posix(de, info);
 604                 break;
 605         case SMB_FIND_FILE_UNIX:
 606                 cifs_fill_dirent_unix(de, info, is_unicode);
 607                 break;
 608         case SMB_FIND_FILE_DIRECTORY_INFO:
 609                 cifs_fill_dirent_dir(de, info);
 610                 break;
 611         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 612                 cifs_fill_dirent_full(de, info);
 613                 break;
 614         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 615                 cifs_fill_dirent_search(de, info);
 616                 break;
 617         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 618                 cifs_fill_dirent_both(de, info);
 619                 break;
 620         case SMB_FIND_FILE_INFO_STANDARD:
 621                 cifs_fill_dirent_std(de, info);
 622                 break;
 623         default:
 624                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 625                 return -EINVAL;
 626         }
 627
 628         return 0;
 629 }
 630
 631 #define UNICODE_DOT cpu_to_le16(0x2e)
 632
 633 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 634 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 635 {
 636         int rc = 0;
 637
 638         if (!de->name)
 639                 return 0;
 640
 641         if (is_unicode) {
 642                 __le16 *ufilename = (__le16 *)de->name;
 643                 if (de->namelen == 2) {
 644                         /* check for . */
 645                         if (ufilename[0] == UNICODE_DOT)
 646                                 rc = 1;
 647                 } else if (de->namelen == 4) {
 648                         /* check for .. */
 649                         if (ufilename[0] == UNICODE_DOT &&
 650                             ufilename[1] == UNICODE_DOT)
 651                                 rc = 2;
 652                 }
 653         } else /* ASCII */ {
 654                 if (de->namelen == 1) {
 655                         if (de->name[0] == '.')
 656                                 rc = 1;
 657                 } else if (de->namelen == 2) {
 658                         if (de->name[0] == '.' && de->name[1] == '.')
 659                                 rc = 2;
 660                 }
 661         }
 662
 663         return rc;
 664 }
 665
 666 /* Check if directory that we are searching has changed so we can decide
 667    whether we can use the cached search results from the previous search */
 668 static int is_dir_changed(struct file *file)
 669 {
 670         struct inode *inode = file_inode(file);
 671         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 672
 673         if (cifsInfo->time == 0)
 674                 return 1; /* directory was changed, perhaps due to unlink */
 675         else
 676                 return 0;
 677
 678 }
 679
 680 static int cifs_save_resume_key(const char *current_entry,
 681         struct cifsFileInfo *file_info)
 682 {
 683         struct cifs_dirent de;
 684         int rc;
 685
 686         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 687                               file_info->srch_inf.unicode);
 688         if (!rc) {
 689                 file_info->srch_inf.presume_name = de.name;
 690                 file_info->srch_inf.resume_name_len = de.namelen;
 691                 file_info->srch_inf.resume_key = de.resume_key;
 692         }
 693         return rc;
 694 }
 695
 696 /*
 697  * Find the corresponding entry in the search. Note that the SMB server returns
 698  * search entries for . and .. which complicates logic here if we choose to
 699  * parse for them and we do not assume that they are located in the findfirst
 700  * return buffer. We start counting in the buffer with entry 2 and increment for
 701  * every entry (do not increment for . or .. entry).
 702  */
 703 static int
 704 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
 705                 struct file *file, const char *full_path,
 706                 char **current_entry, int *num_to_ret)
 707 {
 708         __u16 search_flags;
 709         int rc = 0;
 710         int pos_in_buf = 0;
 711         loff_t first_entry_in_buffer;
 712         loff_t index_to_find = pos;
 713         struct cifsFileInfo *cfile = file->private_data;
 714         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 715         struct TCP_Server_Info *server = tcon->ses->server;
 716         /* check if index in the buffer */
 717
 718         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 719                 return -ENOSYS;
 720
 721         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 722                 return -ENOENT;
 723
 724         *current_entry = NULL;
 725         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 726                                         cfile->srch_inf.entries_in_buffer;
 727
 728         /*
 729          * If first entry in buf is zero then is first buffer
 730          * in search response data which means it is likely . and ..
 731          * will be in this buffer, although some servers do not return
 732          * . and .. for the root of a drive and for those we need
 733          * to start two entries earlier.
 734          */
 735
 736         dump_cifs_file_struct(file, "In fce ");
 737         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 738              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 739                 /* close and restart search */
 740                 cifs_dbg(FYI, "search backing up - close and restart search\n");
 741                 spin_lock(&cfile->file_info_lock);
 742                 if (server->ops->dir_needs_close(cfile)) {
 743                         cfile->invalidHandle = true;
 744                         spin_unlock(&cfile->file_info_lock);
 745                         if (server->ops->close_dir)
 746                                 server->ops->close_dir(xid, tcon, &cfile->fid);
 747                 } else
 748                         spin_unlock(&cfile->file_info_lock);
 749                 if (cfile->srch_inf.ntwrk_buf_start) {
 750                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 751                         if (cfile->srch_inf.smallBuf)
 752                                 cifs_small_buf_release(cfile->srch_inf.
 753                                                 ntwrk_buf_start);
 754                         else
 755                                 cifs_buf_release(cfile->srch_inf.
 756                                                 ntwrk_buf_start);
 757                         cfile->srch_inf.ntwrk_buf_start = NULL;
 758                 }
 759                 rc = initiate_cifs_search(xid, file, full_path);
 760                 if (rc) {
 761                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 762                                  rc);
 763                         return rc;
 764                 }
 765                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 766                 if (cfile->srch_inf.last_entry)
 767                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 768         }
 769
 770         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 771         if (backup_cred(cifs_sb))
 772                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 773
 774         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 775                (rc == 0) && !cfile->srch_inf.endOfSearch) {
 776                 cifs_dbg(FYI, "calling findnext2\n");
 777                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 778                                                  search_flags,
 779                                                  &cfile->srch_inf);
 780                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 781                 if (cfile->srch_inf.last_entry)
 782                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 783                 if (rc)
 784                         return -ENOENT;
 785         }
 786         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 787                 /* we found the buffer that contains the entry */
 788                 /* scan and find it */
 789                 int i;
 790                 char *cur_ent;
 791                 char *end_of_smb;
 792
 793                 if (cfile->srch_inf.ntwrk_buf_start == NULL) {
 794                         cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n");
 795                         return -EIO;
 796                 }
 797
 798                 end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 799                         server->ops->calc_smb_size(
 800                                         cfile->srch_inf.ntwrk_buf_start);
 801
 802                 cur_ent = cfile->srch_inf.srch_entries_start;
 803                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 804                                         - cfile->srch_inf.entries_in_buffer;
 805                 pos_in_buf = index_to_find - first_entry_in_buffer;
 806                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 807
 808                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 809                         /* go entry by entry figuring out which is first */
 810                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 811                                                 cfile->srch_inf.info_level);
 812                 }
 813                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
 814                         /* BB fixme - check if we should flag this error */
 815                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 816                                  pos_in_buf, index_to_find, rc);
 817                 }
 818                 rc = 0;
 819                 *current_entry = cur_ent;
 820         } else {
 821                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 822                 return 0;
 823         }
 824
 825         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 826                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 827                 *num_to_ret = 0;
 828         } else
 829                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 830
 831         return rc;
 832 }
 833
 834 static bool emit_cached_dirents(struct cached_dirents *cde,
 835                                 struct dir_context *ctx)
 836 {
 837         struct cached_dirent *dirent;
 838         bool rc;
 839
 840         list_for_each_entry(dirent, &cde->entries, entry) {
 841                 /*
 842                  * Skip all early entries prior to the current lseek()
 843                  * position.
 844                  */
 845                 if (ctx->pos > dirent->pos)
 846                         continue;
 847                 /*
 848                  * We recorded the current ->pos value for the dirent
 849                  * when we stored it in the cache.
 850                  * However, this sequence of ->pos values may have holes
 851                  * in it, for example dot-dirs returned from the server
 852                  * are suppressed.
 853                  * Handle this bu forcing ctx->pos to be the same as the
 854                  * ->pos of the current dirent we emit from the cache.
 855                  * This means that when we emit these entries from the cache
 856                  * we now emit them with the same ->pos value as in the
 857                  * initial scan.
 858                  */
 859                 ctx->pos = dirent->pos;
 860                 rc = dir_emit(ctx, dirent->name, dirent->namelen,
 861                               dirent->fattr.cf_uniqueid,
 862                               dirent->fattr.cf_dtype);
 863                 if (!rc)
 864                         return rc;
 865                 ctx->pos++;
 866         }
 867         return true;
 868 }
 869
 870 static void update_cached_dirents_count(struct cached_dirents *cde,
 871                                         struct dir_context *ctx)
 872 {
 873         if (cde->ctx != ctx)
 874                 return;
 875         if (cde->is_valid || cde->is_failed)
 876                 return;
 877
 878         cde->pos++;
 879 }
 880
 881 static void finished_cached_dirents_count(struct cached_dirents *cde,
 882                                         struct dir_context *ctx)
 883 {
 884         if (cde->ctx != ctx)
 885                 return;
 886         if (cde->is_valid || cde->is_failed)
 887                 return;
 888         if (ctx->pos != cde->pos)
 889                 return;
 890
 891         cde->is_valid = 1;
 892 }
 893
 894 static void add_cached_dirent(struct cached_dirents *cde,
 895                               struct dir_context *ctx,
 896                               const char *name, int namelen,
 897                               struct cifs_fattr *fattr)
 898 {
 899         struct cached_dirent *de;
 900
 901         if (cde->ctx != ctx)
 902                 return;
 903         if (cde->is_valid || cde->is_failed)
 904                 return;
 905         if (ctx->pos != cde->pos) {
 906                 cde->is_failed = 1;
 907                 return;
 908         }
 909         de = kzalloc(sizeof(*de), GFP_ATOMIC);
 910         if (de == NULL) {
 911                 cde->is_failed = 1;
 912                 return;
 913         }
 914         de->namelen = namelen;
 915         de->name = kstrndup(name, namelen, GFP_ATOMIC);
 916         if (de->name == NULL) {
 917                 kfree(de);
 918                 cde->is_failed = 1;
 919                 return;
 920         }
 921         de->pos = ctx->pos;
 922
 923         memcpy(&de->fattr, fattr, sizeof(struct cifs_fattr));
 924
 925         list_add_tail(&de->entry, &cde->entries);
 926 }
 927
 928 static bool cifs_dir_emit(struct dir_context *ctx,
 929                           const char *name, int namelen,
 930                           struct cifs_fattr *fattr,
 931                           struct cached_fid *cfid)
 932 {
 933         bool rc;
 934         ino_t ino = cifs_uniqueid_to_ino_t(fattr->cf_uniqueid);
 935
 936         rc = dir_emit(ctx, name, namelen, ino, fattr->cf_dtype);
 937         if (!rc)
 938                 return rc;
 939
 940         if (cfid) {
 941                 mutex_lock(&cfid->dirents.de_mutex);
 942                 add_cached_dirent(&cfid->dirents, ctx, name, namelen,
 943                                   fattr);
 944                 mutex_unlock(&cfid->dirents.de_mutex);
 945         }
 946
 947         return rc;
 948 }
 949
 950 static int cifs_filldir(char *find_entry, struct file *file,
 951                         struct dir_context *ctx,
 952                         char *scratch_buf, unsigned int max_len,
 953                         struct cached_fid *cfid)
 954 {
 955         struct cifsFileInfo *file_info = file->private_data;
 956         struct super_block *sb = file_inode(file)->i_sb;
 957         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 958         struct cifs_dirent de = { NULL, };
 959         struct cifs_fattr fattr;
 960         struct qstr name;
 961         int rc = 0;
 962
 963         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 964                               file_info->srch_inf.unicode);
 965         if (rc)
 966                 return rc;
 967
 968         if (de.namelen > max_len) {
 969                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 970                          de.namelen);
 971                 return -EINVAL;
 972         }
 973
 974         /* skip . and .. since we added them first */
 975         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 976                 return 0;
 977
 978         if (file_info->srch_inf.unicode) {
 979                 struct nls_table *nlt = cifs_sb->local_nls;
 980                 int map_type;
 981
 982                 map_type = cifs_remap(cifs_sb);
 983                 name.name = scratch_buf;
 984                 name.len =
 985                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 986                                         UNICODE_NAME_MAX,
 987                                         min_t(size_t, de.namelen,
 988                                               (size_t)max_len), nlt, map_type);
 989                 name.len -= nls_nullsize(nlt);
 990         } else {
 991                 name.name = de.name;
 992                 name.len = de.namelen;
 993         }
 994
 995         switch (file_info->srch_inf.info_level) {
 996         case SMB_FIND_FILE_POSIX_INFO:
 997                 cifs_posix_to_fattr(&fattr,
 998                                     (struct smb2_posix_info *)find_entry,
 999                                     cifs_sb);
1000                 break;
1001         case SMB_FIND_FILE_UNIX:
1002                 cifs_unix_basic_to_fattr(&fattr,
1003                                          &((FILE_UNIX_INFO *)find_entry)->basic,
1004                                          cifs_sb);
1005                 if (S_ISLNK(fattr.cf_mode))
1006                         fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
1007                 break;
1008         case SMB_FIND_FILE_INFO_STANDARD:
1009                 cifs_std_info_to_fattr(&fattr,
1010                                        (FIND_FILE_STANDARD_INFO *)find_entry,
1011                                        cifs_sb);
1012                 break;
1013         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
1014                 cifs_fulldir_info_to_fattr(&fattr,
1015                                            (SEARCH_ID_FULL_DIR_INFO *)find_entry,
1016                                            cifs_sb);
1017                 break;
1018         default:
1019                 cifs_dir_info_to_fattr(&fattr,
1020                                        (FILE_DIRECTORY_INFO *)find_entry,
1021                                        cifs_sb);
1022                 break;
1023         }
1024
1025         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
1026                 fattr.cf_uniqueid = de.ino;
1027         } else {
1028                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
1029                 cifs_autodisable_serverino(cifs_sb);
1030         }
1031
1032         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
1033             couldbe_mf_symlink(&fattr))
1034                 /*
1035                  * trying to get the type and mode can be slow,
1036                  * so just call those regular files for now, and mark
1037                  * for reval
1038                  */
1039                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
1040
1041         cifs_prime_dcache(file_dentry(file), &name, &fattr);
1042
1043         return !cifs_dir_emit(ctx, name.name, name.len,
1044                               &fattr, cfid);
1045 }
1046
1047
1048 int cifs_readdir(struct file *file, struct dir_context *ctx)
1049 {
1050         int rc = 0;
1051         unsigned int xid;
1052         int i;
1053         struct tcon_link *tlink = NULL;
1054         struct cifs_tcon *tcon;
1055         struct cifsFileInfo *cifsFile;
1056         char *current_entry;
1057         int num_to_fill = 0;
1058         char *tmp_buf = NULL;
1059         char *end_of_smb;
1060         unsigned int max_len;
1061         const char *full_path;
1062         void *page = alloc_dentry_path();
1063         struct cached_fid *cfid = NULL;
1064         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
1065
1066         xid = get_xid();
1067
1068         full_path = build_path_from_dentry(file_dentry(file), page);
1069         if (IS_ERR(full_path)) {
1070                 rc = PTR_ERR(full_path);
1071                 goto rddir2_exit;
1072         }
1073
1074         if (file->private_data == NULL) {
1075                 tlink = cifs_sb_tlink(cifs_sb);
1076                 if (IS_ERR(tlink))
1077                         goto cache_not_found;
1078                 tcon = tlink_tcon(tlink);
1079         } else {
1080                 cifsFile = file->private_data;
1081                 tcon = tlink_tcon(cifsFile->tlink);
1082         }
1083
1084         rc = open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
1085         cifs_put_tlink(tlink);
1086         if (rc)
1087                 goto cache_not_found;
1088
1089         mutex_lock(&cfid->dirents.de_mutex);
1090         /*
1091          * If this was reading from the start of the directory
1092          * we need to initialize scanning and storing the
1093          * directory content.
1094          */
1095         if (ctx->pos == 0 && cfid->dirents.ctx == NULL) {
1096                 cfid->dirents.ctx = ctx;
1097                 cfid->dirents.pos = 2;
1098         }
1099         /*
1100          * If we already have the entire directory cached then
1101          * we can just serve the cache.
1102          */
1103         if (cfid->dirents.is_valid) {
1104                 if (!dir_emit_dots(file, ctx)) {
1105                         mutex_unlock(&cfid->dirents.de_mutex);
1106                         goto rddir2_exit;
1107                 }
1108                 emit_cached_dirents(&cfid->dirents, ctx);
1109                 mutex_unlock(&cfid->dirents.de_mutex);
1110                 goto rddir2_exit;
1111         }
1112         mutex_unlock(&cfid->dirents.de_mutex);
1113
1114         /* Drop the cache while calling initiate_cifs_search and
1115          * find_cifs_entry in case there will be reconnects during
1116          * query_directory.
1117          */
1118         close_cached_dir(cfid);
1119         cfid = NULL;
1120
1121  cache_not_found:
1122         /*
1123          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
1124          * '..'. Otherwise we won't be able to notify VFS in case of failure.
1125          */
1126         if (file->private_data == NULL) {
1127                 rc = initiate_cifs_search(xid, file, full_path);
1128                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
1129                 if (rc)
1130                         goto rddir2_exit;
1131         }
1132
1133         if (!dir_emit_dots(file, ctx))
1134                 goto rddir2_exit;
1135
1136         /* 1) If search is active,
1137                 is in current search buffer?
1138                 if it before then restart search
1139                 if after then keep searching till find it */
1140         cifsFile = file->private_data;
1141         if (cifsFile->srch_inf.endOfSearch) {
1142                 if (cifsFile->srch_inf.emptyDir) {
1143                         cifs_dbg(FYI, "End of search, empty dir\n");
1144                         rc = 0;
1145                         goto rddir2_exit;
1146                 }
1147         } /* else {
1148                 cifsFile->invalidHandle = true;
1149                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
1150         } */
1151
1152         tcon = tlink_tcon(cifsFile->tlink);
1153         rc = find_cifs_entry(xid, tcon, ctx->pos, file, full_path,
1154                              &current_entry, &num_to_fill);
1155         open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
1156         if (rc) {
1157                 cifs_dbg(FYI, "fce error %d\n", rc);
1158                 goto rddir2_exit;
1159         } else if (current_entry != NULL) {
1160                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
1161         } else {
1162                 if (cfid) {
1163                         mutex_lock(&cfid->dirents.de_mutex);
1164                         finished_cached_dirents_count(&cfid->dirents, ctx);
1165                         mutex_unlock(&cfid->dirents.de_mutex);
1166                 }
1167                 cifs_dbg(FYI, "Could not find entry\n");
1168                 goto rddir2_exit;
1169         }
1170         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
1171                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
1172         max_len = tcon->ses->server->ops->calc_smb_size(
1173                         cifsFile->srch_inf.ntwrk_buf_start);
1174         end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
1175
1176         tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
1177         if (tmp_buf == NULL) {
1178                 rc = -ENOMEM;
1179                 goto rddir2_exit;
1180         }
1181
1182         for (i = 0; i < num_to_fill; i++) {
1183                 if (current_entry == NULL) {
1184                         /* evaluate whether this case is an error */
1185                         cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
1186                                  num_to_fill, i);
1187                         break;
1188                 }
1189                 /*
1190                  * if buggy server returns . and .. late do we want to
1191                  * check for that here?
1192                  */
1193                 *tmp_buf = 0;
1194                 rc = cifs_filldir(current_entry, file, ctx,
1195                                   tmp_buf, max_len, cfid);
1196                 if (rc) {
1197                         if (rc > 0)
1198                                 rc = 0;
1199                         break;
1200                 }
1201
1202                 ctx->pos++;
1203                 if (cfid) {
1204                         mutex_lock(&cfid->dirents.de_mutex);
1205                         update_cached_dirents_count(&cfid->dirents, ctx);
1206                         mutex_unlock(&cfid->dirents.de_mutex);
1207                 }
1208
1209                 if (ctx->pos ==
1210                         cifsFile->srch_inf.index_of_last_entry) {
1211                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
1212                                  ctx->pos, tmp_buf);
1213                         cifs_save_resume_key(current_entry, cifsFile);
1214                         break;
1215                 }
1216                 current_entry =
1217                         nxt_dir_entry(current_entry, end_of_smb,
1218                                       cifsFile->srch_inf.info_level);
1219         }
1220         kfree(tmp_buf);
1221
1222 rddir2_exit:
1223         if (cfid)
1224                 close_cached_dir(cfid);
1225         free_dentry_path(page);
1226         free_xid(xid);
1227         return rc;
1228 }