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 (sfrench@us.ibm.com)
   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         struct cifs_open_info_data data = {
 157                 .reparse = { .tag = fattr->cf_cifstag, },
 158         };
 159
 160         fattr->cf_uid = cifs_sb->ctx->linux_uid;
 161         fattr->cf_gid = cifs_sb->ctx->linux_gid;
 162
 163         /*
 164          * The IO_REPARSE_TAG_LX_ tags originally were used by WSL but they
 165          * are preferred by the Linux client in some cases since, unlike
 166          * the NFS reparse tag (or EAs), they don't require an extra query
 167          * to determine which type of special file they represent.
 168          * TODO: go through all documented  reparse tags to see if we can
 169          * reasonably map some of them to directories vs. files vs. symlinks
 170          */
 171         if ((fattr->cf_cifsattrs & ATTR_REPARSE) &&
 172             cifs_reparse_point_to_fattr(cifs_sb, fattr, &data))
 173                 goto out_reparse;
 174
 175         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 176                 fattr->cf_mode = S_IFDIR | cifs_sb->ctx->dir_mode;
 177                 fattr->cf_dtype = DT_DIR;
 178         } else {
 179                 fattr->cf_mode = S_IFREG | cifs_sb->ctx->file_mode;
 180                 fattr->cf_dtype = DT_REG;
 181         }
 182
 183 out_reparse:
 184         /*
 185          * We need to revalidate it further to make a decision about whether it
 186          * is a symbolic link, DFS referral or a reparse point with a direct
 187          * access like junctions, deduplicated files, NFS symlinks.
 188          */
 189         if (reparse_file_needs_reval(fattr))
 190                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 191
 192         /* non-unix readdir doesn't provide nlink */
 193         fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
 194
 195         if (fattr->cf_cifsattrs & ATTR_READONLY)
 196                 fattr->cf_mode &= ~S_IWUGO;
 197
 198         /*
 199          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
 200          * mark it for revalidation so that "ls -l" will look right. It might
 201          * be super-slow, but if we don't do this then the ownership of files
 202          * may look wrong since the inodes may not have timed out by the time
 203          * "ls" does a stat() call on them.
 204          */
 205         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) ||
 206             (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID))
 207                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 208
 209         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
 210             fattr->cf_cifsattrs & ATTR_SYSTEM) {
 211                 if (fattr->cf_eof == 0)  {
 212                         fattr->cf_mode &= ~S_IFMT;
 213                         fattr->cf_mode |= S_IFIFO;
 214                         fattr->cf_dtype = DT_FIFO;
 215                 } else {
 216                         /*
 217                          * trying to get the type and mode via SFU can be slow,
 218                          * so just call those regular files for now, and mark
 219                          * for reval
 220                          */
 221                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 222                 }
 223         }
 224 }
 225
 226 /* Fill a cifs_fattr struct with info from SMB_FIND_FILE_POSIX_INFO. */
 227 static void
 228 cifs_posix_to_fattr(struct cifs_fattr *fattr, struct smb2_posix_info *info,
 229                     struct cifs_sb_info *cifs_sb)
 230 {
 231         struct smb2_posix_info_parsed parsed;
 232
 233         posix_info_parse(info, NULL, &parsed);
 234
 235         memset(fattr, 0, sizeof(*fattr));
 236         fattr->cf_uniqueid = le64_to_cpu(info->Inode);
 237         fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
 238         fattr->cf_eof = le64_to_cpu(info->EndOfFile);
 239
 240         fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
 241         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
 242         fattr->cf_ctime = cifs_NTtimeToUnix(info->CreationTime);
 243
 244         fattr->cf_nlink = le32_to_cpu(info->HardLinks);
 245         fattr->cf_cifsattrs = le32_to_cpu(info->DosAttributes);
 246
 247         /*
 248          * Since we set the inode type below we need to mask off
 249          * to avoid strange results if bits set above.
 250          * XXX: why not make server&client use the type bits?
 251          */
 252         fattr->cf_mode = le32_to_cpu(info->Mode) & ~S_IFMT;
 253
 254         cifs_dbg(FYI, "posix fattr: dev %d, reparse %d, mode %o\n",
 255                  le32_to_cpu(info->DeviceId),
 256                  le32_to_cpu(info->ReparseTag),
 257                  le32_to_cpu(info->Mode));
 258
 259         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 260                 fattr->cf_mode |= S_IFDIR;
 261                 fattr->cf_dtype = DT_DIR;
 262         } else {
 263                 /*
 264                  * mark anything that is not a dir as regular
 265                  * file. special files should have the REPARSE
 266                  * attribute and will be marked as needing revaluation
 267                  */
 268                 fattr->cf_mode |= S_IFREG;
 269                 fattr->cf_dtype = DT_REG;
 270         }
 271
 272         if (reparse_file_needs_reval(fattr))
 273                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 274
 275         sid_to_id(cifs_sb, &parsed.owner, fattr, SIDOWNER);
 276         sid_to_id(cifs_sb, &parsed.group, fattr, SIDGROUP);
 277 }
 278
 279 static void __dir_info_to_fattr(struct cifs_fattr *fattr, const void *info)
 280 {
 281         const FILE_DIRECTORY_INFO *fi = info;
 282
 283         memset(fattr, 0, sizeof(*fattr));
 284         fattr->cf_cifsattrs = le32_to_cpu(fi->ExtFileAttributes);
 285         fattr->cf_eof = le64_to_cpu(fi->EndOfFile);
 286         fattr->cf_bytes = le64_to_cpu(fi->AllocationSize);
 287         fattr->cf_createtime = le64_to_cpu(fi->CreationTime);
 288         fattr->cf_atime = cifs_NTtimeToUnix(fi->LastAccessTime);
 289         fattr->cf_ctime = cifs_NTtimeToUnix(fi->ChangeTime);
 290         fattr->cf_mtime = cifs_NTtimeToUnix(fi->LastWriteTime);
 291 }
 292
 293 void
 294 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
 295                        struct cifs_sb_info *cifs_sb)
 296 {
 297         __dir_info_to_fattr(fattr, info);
 298         cifs_fill_common_info(fattr, cifs_sb);
 299 }
 300
 301 static void cifs_fulldir_info_to_fattr(struct cifs_fattr *fattr,
 302                                        SEARCH_ID_FULL_DIR_INFO *info,
 303                                        struct cifs_sb_info *cifs_sb)
 304 {
 305         __dir_info_to_fattr(fattr, info);
 306
 307         /* See MS-FSCC 2.4.19 FileIdFullDirectoryInformation */
 308         if (fattr->cf_cifsattrs & ATTR_REPARSE)
 309                 fattr->cf_cifstag = le32_to_cpu(info->EaSize);
 310         cifs_fill_common_info(fattr, cifs_sb);
 311 }
 312
 313 static void
 314 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 315                        struct cifs_sb_info *cifs_sb)
 316 {
 317         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 318
 319         memset(fattr, 0, sizeof(*fattr));
 320         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
 321                                             info->LastAccessTime, offset);
 322         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
 323                                             info->LastWriteTime, offset);
 324         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
 325                                             info->LastWriteTime, offset);
 326
 327         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
 328         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
 329         fattr->cf_eof = le32_to_cpu(info->DataSize);
 330
 331         cifs_fill_common_info(fattr, cifs_sb);
 332 }
 333
 334 /* BB eventually need to add the following helper function to
 335       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
 336       we try to do FindFirst on (NTFS) directory symlinks */
 337 /*
 338 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 339                              unsigned int xid)
 340 {
 341         __u16 fid;
 342         int len;
 343         int oplock = 0;
 344         int rc;
 345         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
 346         char *tmpbuffer;
 347
 348         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
 349                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 350                         cifs_sb->local_nls,
 351                         cifs_remap(cifs_sb);
 352         if (!rc) {
 353                 tmpbuffer = kmalloc(maxpath);
 354                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
 355                                 tmpbuffer,
 356                                 maxpath -1,
 357                                 fid,
 358                                 cifs_sb->local_nls);
 359                 if (CIFSSMBClose(xid, ptcon, fid)) {
 360                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
 361                 }
 362         }
 363 }
 364  */
 365
 366 static int
 367 _initiate_cifs_search(const unsigned int xid, struct file *file,
 368                      const char *full_path)
 369 {
 370         __u16 search_flags;
 371         int rc = 0;
 372         struct cifsFileInfo *cifsFile;
 373         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 374         struct tcon_link *tlink = NULL;
 375         struct cifs_tcon *tcon;
 376         struct TCP_Server_Info *server;
 377
 378         if (file->private_data == NULL) {
 379                 tlink = cifs_sb_tlink(cifs_sb);
 380                 if (IS_ERR(tlink))
 381                         return PTR_ERR(tlink);
 382
 383                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 384                 if (cifsFile == NULL) {
 385                         rc = -ENOMEM;
 386                         goto error_exit;
 387                 }
 388                 spin_lock_init(&cifsFile->file_info_lock);
 389                 file->private_data = cifsFile;
 390                 cifsFile->tlink = cifs_get_tlink(tlink);
 391                 tcon = tlink_tcon(tlink);
 392         } else {
 393                 cifsFile = file->private_data;
 394                 tcon = tlink_tcon(cifsFile->tlink);
 395         }
 396
 397         server = tcon->ses->server;
 398
 399         if (!server->ops->query_dir_first) {
 400                 rc = -ENOSYS;
 401                 goto error_exit;
 402         }
 403
 404         cifsFile->invalidHandle = true;
 405         cifsFile->srch_inf.endOfSearch = false;
 406
 407         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 408
 409 ffirst_retry:
 410         /* test for Unix extensions */
 411         /* but now check for them on the share/mount not on the SMB session */
 412         /* if (cap_unix(tcon->ses) { */
 413         if (tcon->unix_ext)
 414                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 415         else if (tcon->posix_extensions)
 416                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_POSIX_INFO;
 417         else if ((tcon->ses->capabilities &
 418                   tcon->ses->server->vals->cap_nt_find) == 0) {
 419                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 420         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 421                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 422         } else /* not srvinos - BB fixme add check for backlevel? */ {
 423                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 424         }
 425
 426         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 427         if (backup_cred(cifs_sb))
 428                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 429
 430         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 431                                           &cifsFile->fid, search_flags,
 432                                           &cifsFile->srch_inf);
 433
 434         if (rc == 0)
 435                 cifsFile->invalidHandle = false;
 436         /* BB add following call to handle readdir on new NTFS symlink errors
 437         else if STATUS_STOPPED_ON_SYMLINK
 438                 call get_symlink_reparse_path and retry with new path */
 439         else if ((rc == -EOPNOTSUPP) &&
 440                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 441                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 442                 goto ffirst_retry;
 443         }
 444 error_exit:
 445         cifs_put_tlink(tlink);
 446         return rc;
 447 }
 448
 449 static int
 450 initiate_cifs_search(const unsigned int xid, struct file *file,
 451                      const char *full_path)
 452 {
 453         int rc, retry_count = 0;
 454
 455         do {
 456                 rc = _initiate_cifs_search(xid, file, full_path);
 457                 /*
 458                  * If we don't have enough credits to start reading the
 459                  * directory just try again after short wait.
 460                  */
 461                 if (rc != -EDEADLK)
 462                         break;
 463
 464                 usleep_range(512, 2048);
 465         } while (retry_count++ < 5);
 466
 467         return rc;
 468 }
 469
 470 /* return length of unicode string in bytes */
 471 static int cifs_unicode_bytelen(const char *str)
 472 {
 473         int len;
 474         const __le16 *ustr = (const __le16 *)str;
 475
 476         for (len = 0; len <= PATH_MAX; len++) {
 477                 if (ustr[len] == 0)
 478                         return len << 1;
 479         }
 480         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 481         return len << 1;
 482 }
 483
 484 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 485 {
 486         char *new_entry;
 487         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 488
 489         if (level == SMB_FIND_FILE_INFO_STANDARD) {
 490                 FIND_FILE_STANDARD_INFO *pfData;
 491                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 492
 493                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) + 1 +
 494                                 pfData->FileNameLength;
 495         } else {
 496                 u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset);
 497
 498                 if (old_entry + next_offset < old_entry) {
 499                         cifs_dbg(VFS, "Invalid offset %u\n", next_offset);
 500                         return NULL;
 501                 }
 502                 new_entry = old_entry + next_offset;
 503         }
 504         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 505         /* validate that new_entry is not past end of SMB */
 506         if (new_entry >= end_of_smb) {
 507                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 508                          new_entry, end_of_smb, old_entry);
 509                 return NULL;
 510         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 511                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) + 1 > end_of_smb))
 512                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 513                    (new_entry + sizeof(FILE_DIRECTORY_INFO) + 1 > end_of_smb)))  {
 514                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 515                          new_entry, end_of_smb);
 516                 return NULL;
 517         } else
 518                 return new_entry;
 519
 520 }
 521
 522 struct cifs_dirent {
 523         const char      *name;
 524         size_t          namelen;
 525         u32             resume_key;
 526         u64             ino;
 527 };
 528
 529 static void cifs_fill_dirent_posix(struct cifs_dirent *de,
 530                                    const struct smb2_posix_info *info)
 531 {
 532         struct smb2_posix_info_parsed parsed;
 533
 534         /* payload should have already been checked at this point */
 535         if (posix_info_parse(info, NULL, &parsed) < 0) {
 536                 cifs_dbg(VFS, "Invalid POSIX info payload\n");
 537                 return;
 538         }
 539
 540         de->name = parsed.name;
 541         de->namelen = parsed.name_len;
 542         de->resume_key = info->Ignored;
 543         de->ino = le64_to_cpu(info->Inode);
 544 }
 545
 546 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 547                 const FILE_UNIX_INFO *info, bool is_unicode)
 548 {
 549         de->name = &info->FileName[0];
 550         if (is_unicode)
 551                 de->namelen = cifs_unicode_bytelen(de->name);
 552         else
 553                 de->namelen = strnlen(de->name, PATH_MAX);
 554         de->resume_key = info->ResumeKey;
 555         de->ino = le64_to_cpu(info->basic.UniqueId);
 556 }
 557
 558 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 559                 const FILE_DIRECTORY_INFO *info)
 560 {
 561         de->name = &info->FileName[0];
 562         de->namelen = le32_to_cpu(info->FileNameLength);
 563         de->resume_key = info->FileIndex;
 564 }
 565
 566 static void cifs_fill_dirent_full(struct cifs_dirent *de,
 567                 const FILE_FULL_DIRECTORY_INFO *info)
 568 {
 569         de->name = &info->FileName[0];
 570         de->namelen = le32_to_cpu(info->FileNameLength);
 571         de->resume_key = info->FileIndex;
 572 }
 573
 574 static void cifs_fill_dirent_search(struct cifs_dirent *de,
 575                 const SEARCH_ID_FULL_DIR_INFO *info)
 576 {
 577         de->name = &info->FileName[0];
 578         de->namelen = le32_to_cpu(info->FileNameLength);
 579         de->resume_key = info->FileIndex;
 580         de->ino = le64_to_cpu(info->UniqueId);
 581 }
 582
 583 static void cifs_fill_dirent_both(struct cifs_dirent *de,
 584                 const FILE_BOTH_DIRECTORY_INFO *info)
 585 {
 586         de->name = &info->FileName[0];
 587         de->namelen = le32_to_cpu(info->FileNameLength);
 588         de->resume_key = info->FileIndex;
 589 }
 590
 591 static void cifs_fill_dirent_std(struct cifs_dirent *de,
 592                 const FIND_FILE_STANDARD_INFO *info)
 593 {
 594         de->name = &info->FileName[0];
 595         /* one byte length, no endianess conversion */
 596         de->namelen = info->FileNameLength;
 597         de->resume_key = info->ResumeKey;
 598 }
 599
 600 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 601                 u16 level, bool is_unicode)
 602 {
 603         memset(de, 0, sizeof(*de));
 604
 605         switch (level) {
 606         case SMB_FIND_FILE_POSIX_INFO:
 607                 cifs_fill_dirent_posix(de, info);
 608                 break;
 609         case SMB_FIND_FILE_UNIX:
 610                 cifs_fill_dirent_unix(de, info, is_unicode);
 611                 break;
 612         case SMB_FIND_FILE_DIRECTORY_INFO:
 613                 cifs_fill_dirent_dir(de, info);
 614                 break;
 615         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 616                 cifs_fill_dirent_full(de, info);
 617                 break;
 618         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 619                 cifs_fill_dirent_search(de, info);
 620                 break;
 621         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 622                 cifs_fill_dirent_both(de, info);
 623                 break;
 624         case SMB_FIND_FILE_INFO_STANDARD:
 625                 cifs_fill_dirent_std(de, info);
 626                 break;
 627         default:
 628                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 629                 return -EINVAL;
 630         }
 631
 632         return 0;
 633 }
 634
 635 #define UNICODE_DOT cpu_to_le16(0x2e)
 636
 637 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 638 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 639 {
 640         int rc = 0;
 641
 642         if (!de->name)
 643                 return 0;
 644
 645         if (is_unicode) {
 646                 __le16 *ufilename = (__le16 *)de->name;
 647                 if (de->namelen == 2) {
 648                         /* check for . */
 649                         if (ufilename[0] == UNICODE_DOT)
 650                                 rc = 1;
 651                 } else if (de->namelen == 4) {
 652                         /* check for .. */
 653                         if (ufilename[0] == UNICODE_DOT &&
 654                             ufilename[1] == UNICODE_DOT)
 655                                 rc = 2;
 656                 }
 657         } else /* ASCII */ {
 658                 if (de->namelen == 1) {
 659                         if (de->name[0] == '.')
 660                                 rc = 1;
 661                 } else if (de->namelen == 2) {
 662                         if (de->name[0] == '.' && de->name[1] == '.')
 663                                 rc = 2;
 664                 }
 665         }
 666
 667         return rc;
 668 }
 669
 670 /* Check if directory that we are searching has changed so we can decide
 671    whether we can use the cached search results from the previous search */
 672 static int is_dir_changed(struct file *file)
 673 {
 674         struct inode *inode = file_inode(file);
 675         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 676
 677         if (cifsInfo->time == 0)
 678                 return 1; /* directory was changed, perhaps due to unlink */
 679         else
 680                 return 0;
 681
 682 }
 683
 684 static int cifs_save_resume_key(const char *current_entry,
 685         struct cifsFileInfo *file_info)
 686 {
 687         struct cifs_dirent de;
 688         int rc;
 689
 690         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 691                               file_info->srch_inf.unicode);
 692         if (!rc) {
 693                 file_info->srch_inf.presume_name = de.name;
 694                 file_info->srch_inf.resume_name_len = de.namelen;
 695                 file_info->srch_inf.resume_key = de.resume_key;
 696         }
 697         return rc;
 698 }
 699
 700 /*
 701  * Find the corresponding entry in the search. Note that the SMB server returns
 702  * search entries for . and .. which complicates logic here if we choose to
 703  * parse for them and we do not assume that they are located in the findfirst
 704  * return buffer. We start counting in the buffer with entry 2 and increment for
 705  * every entry (do not increment for . or .. entry).
 706  */
 707 static int
 708 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
 709                 struct file *file, const char *full_path,
 710                 char **current_entry, int *num_to_ret)
 711 {
 712         __u16 search_flags;
 713         int rc = 0;
 714         int pos_in_buf = 0;
 715         loff_t first_entry_in_buffer;
 716         loff_t index_to_find = pos;
 717         struct cifsFileInfo *cfile = file->private_data;
 718         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 719         struct TCP_Server_Info *server = tcon->ses->server;
 720         /* check if index in the buffer */
 721
 722         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 723                 return -ENOSYS;
 724
 725         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 726                 return -ENOENT;
 727
 728         *current_entry = NULL;
 729         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 730                                         cfile->srch_inf.entries_in_buffer;
 731
 732         /*
 733          * If first entry in buf is zero then is first buffer
 734          * in search response data which means it is likely . and ..
 735          * will be in this buffer, although some servers do not return
 736          * . and .. for the root of a drive and for those we need
 737          * to start two entries earlier.
 738          */
 739
 740         dump_cifs_file_struct(file, "In fce ");
 741         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 742              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 743                 /* close and restart search */
 744                 cifs_dbg(FYI, "search backing up - close and restart search\n");
 745                 spin_lock(&cfile->file_info_lock);
 746                 if (server->ops->dir_needs_close(cfile)) {
 747                         cfile->invalidHandle = true;
 748                         spin_unlock(&cfile->file_info_lock);
 749                         if (server->ops->close_dir)
 750                                 server->ops->close_dir(xid, tcon, &cfile->fid);
 751                 } else
 752                         spin_unlock(&cfile->file_info_lock);
 753                 if (cfile->srch_inf.ntwrk_buf_start) {
 754                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 755                         if (cfile->srch_inf.smallBuf)
 756                                 cifs_small_buf_release(cfile->srch_inf.
 757                                                 ntwrk_buf_start);
 758                         else
 759                                 cifs_buf_release(cfile->srch_inf.
 760                                                 ntwrk_buf_start);
 761                         cfile->srch_inf.ntwrk_buf_start = NULL;
 762                 }
 763                 rc = initiate_cifs_search(xid, file, full_path);
 764                 if (rc) {
 765                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 766                                  rc);
 767                         return rc;
 768                 }
 769                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 770                 if (cfile->srch_inf.last_entry)
 771                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 772         }
 773
 774         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 775         if (backup_cred(cifs_sb))
 776                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 777
 778         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 779                (rc == 0) && !cfile->srch_inf.endOfSearch) {
 780                 cifs_dbg(FYI, "calling findnext2\n");
 781                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 782                                                  search_flags,
 783                                                  &cfile->srch_inf);
 784                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 785                 if (cfile->srch_inf.last_entry)
 786                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 787                 if (rc)
 788                         return -ENOENT;
 789         }
 790         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 791                 /* we found the buffer that contains the entry */
 792                 /* scan and find it */
 793                 int i;
 794                 char *cur_ent;
 795                 char *end_of_smb;
 796
 797                 if (cfile->srch_inf.ntwrk_buf_start == NULL) {
 798                         cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n");
 799                         return -EIO;
 800                 }
 801
 802                 end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 803                         server->ops->calc_smb_size(
 804                                         cfile->srch_inf.ntwrk_buf_start);
 805
 806                 cur_ent = cfile->srch_inf.srch_entries_start;
 807                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 808                                         - cfile->srch_inf.entries_in_buffer;
 809                 pos_in_buf = index_to_find - first_entry_in_buffer;
 810                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 811
 812                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 813                         /* go entry by entry figuring out which is first */
 814                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 815                                                 cfile->srch_inf.info_level);
 816                 }
 817                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
 818                         /* BB fixme - check if we should flag this error */
 819                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 820                                  pos_in_buf, index_to_find, rc);
 821                 }
 822                 rc = 0;
 823                 *current_entry = cur_ent;
 824         } else {
 825                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 826                 return 0;
 827         }
 828
 829         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 830                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 831                 *num_to_ret = 0;
 832         } else
 833                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 834
 835         return rc;
 836 }
 837
 838 static bool emit_cached_dirents(struct cached_dirents *cde,
 839                                 struct dir_context *ctx)
 840 {
 841         struct cached_dirent *dirent;
 842         bool rc;
 843
 844         list_for_each_entry(dirent, &cde->entries, entry) {
 845                 /*
 846                  * Skip all early entries prior to the current lseek()
 847                  * position.
 848                  */
 849                 if (ctx->pos > dirent->pos)
 850                         continue;
 851                 /*
 852                  * We recorded the current ->pos value for the dirent
 853                  * when we stored it in the cache.
 854                  * However, this sequence of ->pos values may have holes
 855                  * in it, for example dot-dirs returned from the server
 856                  * are suppressed.
 857                  * Handle this bu forcing ctx->pos to be the same as the
 858                  * ->pos of the current dirent we emit from the cache.
 859                  * This means that when we emit these entries from the cache
 860                  * we now emit them with the same ->pos value as in the
 861                  * initial scan.
 862                  */
 863                 ctx->pos = dirent->pos;
 864                 rc = dir_emit(ctx, dirent->name, dirent->namelen,
 865                               dirent->fattr.cf_uniqueid,
 866                               dirent->fattr.cf_dtype);
 867                 if (!rc)
 868                         return rc;
 869                 ctx->pos++;
 870         }
 871         return true;
 872 }
 873
 874 static void update_cached_dirents_count(struct cached_dirents *cde,
 875                                         struct dir_context *ctx)
 876 {
 877         if (cde->ctx != ctx)
 878                 return;
 879         if (cde->is_valid || cde->is_failed)
 880                 return;
 881
 882         cde->pos++;
 883 }
 884
 885 static void finished_cached_dirents_count(struct cached_dirents *cde,
 886                                         struct dir_context *ctx)
 887 {
 888         if (cde->ctx != ctx)
 889                 return;
 890         if (cde->is_valid || cde->is_failed)
 891                 return;
 892         if (ctx->pos != cde->pos)
 893                 return;
 894
 895         cde->is_valid = 1;
 896 }
 897
 898 static void add_cached_dirent(struct cached_dirents *cde,
 899                               struct dir_context *ctx,
 900                               const char *name, int namelen,
 901                               struct cifs_fattr *fattr)
 902 {
 903         struct cached_dirent *de;
 904
 905         if (cde->ctx != ctx)
 906                 return;
 907         if (cde->is_valid || cde->is_failed)
 908                 return;
 909         if (ctx->pos != cde->pos) {
 910                 cde->is_failed = 1;
 911                 return;
 912         }
 913         de = kzalloc(sizeof(*de), GFP_ATOMIC);
 914         if (de == NULL) {
 915                 cde->is_failed = 1;
 916                 return;
 917         }
 918         de->namelen = namelen;
 919         de->name = kstrndup(name, namelen, GFP_ATOMIC);
 920         if (de->name == NULL) {
 921                 kfree(de);
 922                 cde->is_failed = 1;
 923                 return;
 924         }
 925         de->pos = ctx->pos;
 926
 927         memcpy(&de->fattr, fattr, sizeof(struct cifs_fattr));
 928
 929         list_add_tail(&de->entry, &cde->entries);
 930 }
 931
 932 static bool cifs_dir_emit(struct dir_context *ctx,
 933                           const char *name, int namelen,
 934                           struct cifs_fattr *fattr,
 935                           struct cached_fid *cfid)
 936 {
 937         bool rc;
 938         ino_t ino = cifs_uniqueid_to_ino_t(fattr->cf_uniqueid);
 939
 940         rc = dir_emit(ctx, name, namelen, ino, fattr->cf_dtype);
 941         if (!rc)
 942                 return rc;
 943
 944         if (cfid) {
 945                 mutex_lock(&cfid->dirents.de_mutex);
 946                 add_cached_dirent(&cfid->dirents, ctx, name, namelen,
 947                                   fattr);
 948                 mutex_unlock(&cfid->dirents.de_mutex);
 949         }
 950
 951         return rc;
 952 }
 953
 954 static int cifs_filldir(char *find_entry, struct file *file,
 955                         struct dir_context *ctx,
 956                         char *scratch_buf, unsigned int max_len,
 957                         struct cached_fid *cfid)
 958 {
 959         struct cifsFileInfo *file_info = file->private_data;
 960         struct super_block *sb = file_inode(file)->i_sb;
 961         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 962         struct cifs_dirent de = { NULL, };
 963         struct cifs_fattr fattr;
 964         struct qstr name;
 965         int rc = 0;
 966
 967         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 968                               file_info->srch_inf.unicode);
 969         if (rc)
 970                 return rc;
 971
 972         if (de.namelen > max_len) {
 973                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 974                          de.namelen);
 975                 return -EINVAL;
 976         }
 977
 978         /* skip . and .. since we added them first */
 979         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 980                 return 0;
 981
 982         if (file_info->srch_inf.unicode) {
 983                 struct nls_table *nlt = cifs_sb->local_nls;
 984                 int map_type;
 985
 986                 map_type = cifs_remap(cifs_sb);
 987                 name.name = scratch_buf;
 988                 name.len =
 989                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 990                                         UNICODE_NAME_MAX,
 991                                         min_t(size_t, de.namelen,
 992                                               (size_t)max_len), nlt, map_type);
 993                 name.len -= nls_nullsize(nlt);
 994         } else {
 995                 name.name = de.name;
 996                 name.len = de.namelen;
 997         }
 998
 999         switch (file_info->srch_inf.info_level) {
1000         case SMB_FIND_FILE_POSIX_INFO:
1001                 cifs_posix_to_fattr(&fattr,
1002                                     (struct smb2_posix_info *)find_entry,
1003                                     cifs_sb);
1004                 break;
1005         case SMB_FIND_FILE_UNIX:
1006                 cifs_unix_basic_to_fattr(&fattr,
1007                                          &((FILE_UNIX_INFO *)find_entry)->basic,
1008                                          cifs_sb);
1009                 if (S_ISLNK(fattr.cf_mode))
1010                         fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
1011                 break;
1012         case SMB_FIND_FILE_INFO_STANDARD:
1013                 cifs_std_info_to_fattr(&fattr,
1014                                        (FIND_FILE_STANDARD_INFO *)find_entry,
1015                                        cifs_sb);
1016                 break;
1017         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
1018                 cifs_fulldir_info_to_fattr(&fattr,
1019                                            (SEARCH_ID_FULL_DIR_INFO *)find_entry,
1020                                            cifs_sb);
1021                 break;
1022         default:
1023                 cifs_dir_info_to_fattr(&fattr,
1024                                        (FILE_DIRECTORY_INFO *)find_entry,
1025                                        cifs_sb);
1026                 break;
1027         }
1028
1029         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
1030                 fattr.cf_uniqueid = de.ino;
1031         } else {
1032                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
1033                 cifs_autodisable_serverino(cifs_sb);
1034         }
1035
1036         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
1037             couldbe_mf_symlink(&fattr))
1038                 /*
1039                  * trying to get the type and mode can be slow,
1040                  * so just call those regular files for now, and mark
1041                  * for reval
1042                  */
1043                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
1044
1045         cifs_prime_dcache(file_dentry(file), &name, &fattr);
1046
1047         return !cifs_dir_emit(ctx, name.name, name.len,
1048                               &fattr, cfid);
1049 }
1050
1051
1052 int cifs_readdir(struct file *file, struct dir_context *ctx)
1053 {
1054         int rc = 0;
1055         unsigned int xid;
1056         int i;
1057         struct tcon_link *tlink = NULL;
1058         struct cifs_tcon *tcon;
1059         struct cifsFileInfo *cifsFile;
1060         char *current_entry;
1061         int num_to_fill = 0;
1062         char *tmp_buf = NULL;
1063         char *end_of_smb;
1064         unsigned int max_len;
1065         const char *full_path;
1066         void *page = alloc_dentry_path();
1067         struct cached_fid *cfid = NULL;
1068         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
1069
1070         xid = get_xid();
1071
1072         full_path = build_path_from_dentry(file_dentry(file), page);
1073         if (IS_ERR(full_path)) {
1074                 rc = PTR_ERR(full_path);
1075                 goto rddir2_exit;
1076         }
1077
1078         if (file->private_data == NULL) {
1079                 tlink = cifs_sb_tlink(cifs_sb);
1080                 if (IS_ERR(tlink))
1081                         goto cache_not_found;
1082                 tcon = tlink_tcon(tlink);
1083         } else {
1084                 cifsFile = file->private_data;
1085                 tcon = tlink_tcon(cifsFile->tlink);
1086         }
1087
1088         rc = open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
1089         cifs_put_tlink(tlink);
1090         if (rc)
1091                 goto cache_not_found;
1092
1093         mutex_lock(&cfid->dirents.de_mutex);
1094         /*
1095          * If this was reading from the start of the directory
1096          * we need to initialize scanning and storing the
1097          * directory content.
1098          */
1099         if (ctx->pos == 0 && cfid->dirents.ctx == NULL) {
1100                 cfid->dirents.ctx = ctx;
1101                 cfid->dirents.pos = 2;
1102         }
1103         /*
1104          * If we already have the entire directory cached then
1105          * we can just serve the cache.
1106          */
1107         if (cfid->dirents.is_valid) {
1108                 if (!dir_emit_dots(file, ctx)) {
1109                         mutex_unlock(&cfid->dirents.de_mutex);
1110                         goto rddir2_exit;
1111                 }
1112                 emit_cached_dirents(&cfid->dirents, ctx);
1113                 mutex_unlock(&cfid->dirents.de_mutex);
1114                 goto rddir2_exit;
1115         }
1116         mutex_unlock(&cfid->dirents.de_mutex);
1117
1118         /* Drop the cache while calling initiate_cifs_search and
1119          * find_cifs_entry in case there will be reconnects during
1120          * query_directory.
1121          */
1122         close_cached_dir(cfid);
1123         cfid = NULL;
1124
1125  cache_not_found:
1126         /*
1127          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
1128          * '..'. Otherwise we won't be able to notify VFS in case of failure.
1129          */
1130         if (file->private_data == NULL) {
1131                 rc = initiate_cifs_search(xid, file, full_path);
1132                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
1133                 if (rc)
1134                         goto rddir2_exit;
1135         }
1136
1137         if (!dir_emit_dots(file, ctx))
1138                 goto rddir2_exit;
1139
1140         /* 1) If search is active,
1141                 is in current search buffer?
1142                 if it before then restart search
1143                 if after then keep searching till find it */
1144         cifsFile = file->private_data;
1145         if (cifsFile->srch_inf.endOfSearch) {
1146                 if (cifsFile->srch_inf.emptyDir) {
1147                         cifs_dbg(FYI, "End of search, empty dir\n");
1148                         rc = 0;
1149                         goto rddir2_exit;
1150                 }
1151         } /* else {
1152                 cifsFile->invalidHandle = true;
1153                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
1154         } */
1155
1156         tcon = tlink_tcon(cifsFile->tlink);
1157         rc = find_cifs_entry(xid, tcon, ctx->pos, file, full_path,
1158                              &current_entry, &num_to_fill);
1159         open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
1160         if (rc) {
1161                 cifs_dbg(FYI, "fce error %d\n", rc);
1162                 goto rddir2_exit;
1163         } else if (current_entry != NULL) {
1164                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
1165         } else {
1166                 if (cfid) {
1167                         mutex_lock(&cfid->dirents.de_mutex);
1168                         finished_cached_dirents_count(&cfid->dirents, ctx);
1169                         mutex_unlock(&cfid->dirents.de_mutex);
1170                 }
1171                 cifs_dbg(FYI, "Could not find entry\n");
1172                 goto rddir2_exit;
1173         }
1174         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
1175                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
1176         max_len = tcon->ses->server->ops->calc_smb_size(
1177                         cifsFile->srch_inf.ntwrk_buf_start);
1178         end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
1179
1180         tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
1181         if (tmp_buf == NULL) {
1182                 rc = -ENOMEM;
1183                 goto rddir2_exit;
1184         }
1185
1186         for (i = 0; i < num_to_fill; i++) {
1187                 if (current_entry == NULL) {
1188                         /* evaluate whether this case is an error */
1189                         cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
1190                                  num_to_fill, i);
1191                         break;
1192                 }
1193                 /*
1194                  * if buggy server returns . and .. late do we want to
1195                  * check for that here?
1196                  */
1197                 *tmp_buf = 0;
1198                 rc = cifs_filldir(current_entry, file, ctx,
1199                                   tmp_buf, max_len, cfid);
1200                 if (rc) {
1201                         if (rc > 0)
1202                                 rc = 0;
1203                         break;
1204                 }
1205
1206                 ctx->pos++;
1207                 if (cfid) {
1208                         mutex_lock(&cfid->dirents.de_mutex);
1209                         update_cached_dirents_count(&cfid->dirents, ctx);
1210                         mutex_unlock(&cfid->dirents.de_mutex);
1211                 }
1212
1213                 if (ctx->pos ==
1214                         cifsFile->srch_inf.index_of_last_entry) {
1215                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
1216                                  ctx->pos, tmp_buf);
1217                         cifs_save_resume_key(current_entry, cifsFile);
1218                         break;
1219                 }
1220                 current_entry =
1221                         nxt_dir_entry(current_entry, end_of_smb,
1222                                       cifsFile->srch_inf.info_level);
1223         }
1224         kfree(tmp_buf);
1225
1226 rddir2_exit:
1227         if (cfid)
1228                 close_cached_dir(cfid);
1229         free_dentry_path(page);
1230         free_xid(xid);
1231         return rc;
1232 }