fs/cifs/readdir.c

   1 /*
   2  *   fs/cifs/readdir.c
   3  *
   4  *   Directory search handling
   5  *
   6  *   Copyright (C) International Business Machines  Corp., 2004, 2008
   7  *   Copyright (C) Red Hat, Inc., 2011
   8  *   Author(s): Steve French (sfrench@us.ibm.com)
   9  *
  10  *   This library is free software; you can redistribute it and/or modify
  11  *   it under the terms of the GNU Lesser General Public License as published
  12  *   by the Free Software Foundation; either version 2.1 of the License, or
  13  *   (at your option) any later version.
  14  *
  15  *   This library is distributed in the hope that it will be useful,
  16  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  18  *   the GNU Lesser General Public License for more details.
  19  *
  20  *   You should have received a copy of the GNU Lesser General Public License
  21  *   along with this library; if not, write to the Free Software
  22  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  */
  24 #include <linux/fs.h>
  25 #include <linux/pagemap.h>
  26 #include <linux/slab.h>
  27 #include <linux/stat.h>
  28 #include "cifspdu.h"
  29 #include "cifsglob.h"
  30 #include "cifsproto.h"
  31 #include "cifs_unicode.h"
  32 #include "cifs_debug.h"
  33 #include "cifs_fs_sb.h"
  34 #include "cifsfs.h"
  35
  36 /*
  37  * To be safe - for UCS to UTF-8 with strings loaded with the rare long
  38  * characters alloc more to account for such multibyte target UTF-8
  39  * characters.
  40  */
  41 #define UNICODE_NAME_MAX ((4 * NAME_MAX) + 2)
  42
  43 #ifdef CONFIG_CIFS_DEBUG2
  44 static void dump_cifs_file_struct(struct file *file, char *label)
  45 {
  46         struct cifsFileInfo *cf;
  47
  48         if (file) {
  49                 cf = file->private_data;
  50                 if (cf == NULL) {
  51                         cifs_dbg(FYI, "empty cifs private file data\n");
  52                         return;
  53                 }
  54                 if (cf->invalidHandle)
  55                         cifs_dbg(FYI, "invalid handle\n");
  56                 if (cf->srch_inf.endOfSearch)
  57                         cifs_dbg(FYI, "end of search\n");
  58                 if (cf->srch_inf.emptyDir)
  59                         cifs_dbg(FYI, "empty dir\n");
  60         }
  61 }
  62 #else
  63 static inline void dump_cifs_file_struct(struct file *file, char *label)
  64 {
  65 }
  66 #endif /* DEBUG2 */
  67
  68 /*
  69  * Attempt to preload the dcache with the results from the FIND_FIRST/NEXT
  70  *
  71  * Find the dentry that matches "name". If there isn't one, create one. If it's
  72  * a negative dentry or the uniqueid or filetype(mode) changed,
  73  * then drop it and recreate it.
  74  */
  75 static void
  76 cifs_prime_dcache(struct dentry *parent, struct qstr *name,
  77                     struct cifs_fattr *fattr)
  78 {
  79         struct dentry *dentry, *alias;
  80         struct inode *inode;
  81         struct super_block *sb = parent->d_sb;
  82         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
  83         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
  84
  85         cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
  86
  87         dentry = d_hash_and_lookup(parent, name);
  88         if (!dentry) {
  89                 /*
  90                  * If we know that the inode will need to be revalidated
  91                  * immediately, then don't create a new dentry for it.
  92                  * We'll end up doing an on the wire call either way and
  93                  * this spares us an invalidation.
  94                  */
  95                 if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
  96                         return;
  97 retry:
  98                 dentry = d_alloc_parallel(parent, name, &wq);
  99         }
 100         if (IS_ERR(dentry))
 101                 return;
 102         if (!d_in_lookup(dentry)) {
 103                 inode = d_inode(dentry);
 104                 if (inode) {
 105                         if (d_mountpoint(dentry)) {
 106                                 dput(dentry);
 107                                 return;
 108                         }
 109                         /*
 110                          * If we're generating inode numbers, then we don't
 111                          * want to clobber the existing one with the one that
 112                          * the readdir code created.
 113                          */
 114                         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
 115                                 fattr->cf_uniqueid = CIFS_I(inode)->uniqueid;
 116
 117                         /* update inode in place
 118                          * if both i_ino and i_mode didn't change */
 119                         if (CIFS_I(inode)->uniqueid == fattr->cf_uniqueid &&
 120                             (inode->i_mode & S_IFMT) ==
 121                             (fattr->cf_mode & S_IFMT)) {
 122                                 cifs_fattr_to_inode(inode, fattr);
 123                                 dput(dentry);
 124                                 return;
 125                         }
 126                 }
 127                 d_invalidate(dentry);
 128                 dput(dentry);
 129                 goto retry;
 130         } else {
 131                 inode = cifs_iget(sb, fattr);
 132                 if (!inode)
 133                         inode = ERR_PTR(-ENOMEM);
 134                 alias = d_splice_alias(inode, dentry);
 135                 d_lookup_done(dentry);
 136                 if (alias && !IS_ERR(alias))
 137                         dput(alias);
 138         }
 139         dput(dentry);
 140 }
 141
 142 static void
 143 cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
 144 {
 145         fattr->cf_uid = cifs_sb->mnt_uid;
 146         fattr->cf_gid = cifs_sb->mnt_gid;
 147
 148         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 149                 fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
 150                 fattr->cf_dtype = DT_DIR;
 151         } else {
 152                 fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
 153                 fattr->cf_dtype = DT_REG;
 154         }
 155
 156         /*
 157          * We need to revalidate it further to make a decision about whether it
 158          * is a symbolic link, DFS referral or a reparse point with a direct
 159          * access like junctions, deduplicated files, NFS symlinks.
 160          */
 161         if (fattr->cf_cifsattrs & ATTR_REPARSE)
 162                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 163
 164         /* non-unix readdir doesn't provide nlink */
 165         fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
 166
 167         if (fattr->cf_cifsattrs & ATTR_READONLY)
 168                 fattr->cf_mode &= ~S_IWUGO;
 169
 170         /*
 171          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
 172          * mark it for revalidation so that "ls -l" will look right. It might
 173          * be super-slow, but if we don't do this then the ownership of files
 174          * may look wrong since the inodes may not have timed out by the time
 175          * "ls" does a stat() call on them.
 176          */
 177         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL)
 178                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 179
 180         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
 181             fattr->cf_cifsattrs & ATTR_SYSTEM) {
 182                 if (fattr->cf_eof == 0)  {
 183                         fattr->cf_mode &= ~S_IFMT;
 184                         fattr->cf_mode |= S_IFIFO;
 185                         fattr->cf_dtype = DT_FIFO;
 186                 } else {
 187                         /*
 188                          * trying to get the type and mode via SFU can be slow,
 189                          * so just call those regular files for now, and mark
 190                          * for reval
 191                          */
 192                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 193                 }
 194         }
 195 }
 196
 197 void
 198 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
 199                        struct cifs_sb_info *cifs_sb)
 200 {
 201         memset(fattr, 0, sizeof(*fattr));
 202         fattr->cf_cifsattrs = le32_to_cpu(info->ExtFileAttributes);
 203         fattr->cf_eof = le64_to_cpu(info->EndOfFile);
 204         fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
 205         fattr->cf_createtime = le64_to_cpu(info->CreationTime);
 206         fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
 207         fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
 208         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
 209
 210         cifs_fill_common_info(fattr, cifs_sb);
 211 }
 212
 213 static void
 214 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 215                        struct cifs_sb_info *cifs_sb)
 216 {
 217         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 218
 219         memset(fattr, 0, sizeof(*fattr));
 220         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
 221                                             info->LastAccessTime, offset);
 222         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
 223                                             info->LastWriteTime, offset);
 224         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
 225                                             info->LastWriteTime, offset);
 226
 227         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
 228         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
 229         fattr->cf_eof = le32_to_cpu(info->DataSize);
 230
 231         cifs_fill_common_info(fattr, cifs_sb);
 232 }
 233
 234 /* BB eventually need to add the following helper function to
 235       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
 236       we try to do FindFirst on (NTFS) directory symlinks */
 237 /*
 238 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 239                              unsigned int xid)
 240 {
 241         __u16 fid;
 242         int len;
 243         int oplock = 0;
 244         int rc;
 245         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
 246         char *tmpbuffer;
 247
 248         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
 249                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 250                         cifs_sb->local_nls,
 251                         cifs_remap(cifs_sb);
 252         if (!rc) {
 253                 tmpbuffer = kmalloc(maxpath);
 254                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
 255                                 tmpbuffer,
 256                                 maxpath -1,
 257                                 fid,
 258                                 cifs_sb->local_nls);
 259                 if (CIFSSMBClose(xid, ptcon, fid)) {
 260                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
 261                 }
 262         }
 263 }
 264  */
 265
 266 static int
 267 initiate_cifs_search(const unsigned int xid, struct file *file)
 268 {
 269         __u16 search_flags;
 270         int rc = 0;
 271         char *full_path = NULL;
 272         struct cifsFileInfo *cifsFile;
 273         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 274         struct tcon_link *tlink = NULL;
 275         struct cifs_tcon *tcon;
 276         struct TCP_Server_Info *server;
 277
 278         if (file->private_data == NULL) {
 279                 tlink = cifs_sb_tlink(cifs_sb);
 280                 if (IS_ERR(tlink))
 281                         return PTR_ERR(tlink);
 282
 283                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 284                 if (cifsFile == NULL) {
 285                         rc = -ENOMEM;
 286                         goto error_exit;
 287                 }
 288                 spin_lock_init(&cifsFile->file_info_lock);
 289                 file->private_data = cifsFile;
 290                 cifsFile->tlink = cifs_get_tlink(tlink);
 291                 tcon = tlink_tcon(tlink);
 292         } else {
 293                 cifsFile = file->private_data;
 294                 tcon = tlink_tcon(cifsFile->tlink);
 295         }
 296
 297         server = tcon->ses->server;
 298
 299         if (!server->ops->query_dir_first) {
 300                 rc = -ENOSYS;
 301                 goto error_exit;
 302         }
 303
 304         cifsFile->invalidHandle = true;
 305         cifsFile->srch_inf.endOfSearch = false;
 306
 307         full_path = build_path_from_dentry(file_dentry(file));
 308         if (full_path == NULL) {
 309                 rc = -ENOMEM;
 310                 goto error_exit;
 311         }
 312
 313         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 314
 315 ffirst_retry:
 316         /* test for Unix extensions */
 317         /* but now check for them on the share/mount not on the SMB session */
 318         /* if (cap_unix(tcon->ses) { */
 319         if (tcon->unix_ext)
 320                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 321         else if ((tcon->ses->capabilities &
 322                   tcon->ses->server->vals->cap_nt_find) == 0) {
 323                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 324         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 325                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 326         } else /* not srvinos - BB fixme add check for backlevel? */ {
 327                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 328         }
 329
 330         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 331         if (backup_cred(cifs_sb))
 332                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 333
 334         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 335                                           &cifsFile->fid, search_flags,
 336                                           &cifsFile->srch_inf);
 337
 338         if (rc == 0)
 339                 cifsFile->invalidHandle = false;
 340         /* BB add following call to handle readdir on new NTFS symlink errors
 341         else if STATUS_STOPPED_ON_SYMLINK
 342                 call get_symlink_reparse_path and retry with new path */
 343         else if ((rc == -EOPNOTSUPP) &&
 344                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 345                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 346                 goto ffirst_retry;
 347         }
 348 error_exit:
 349         kfree(full_path);
 350         cifs_put_tlink(tlink);
 351         return rc;
 352 }
 353
 354 /* return length of unicode string in bytes */
 355 static int cifs_unicode_bytelen(const char *str)
 356 {
 357         int len;
 358         const __le16 *ustr = (const __le16 *)str;
 359
 360         for (len = 0; len <= PATH_MAX; len++) {
 361                 if (ustr[len] == 0)
 362                         return len << 1;
 363         }
 364         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 365         return len << 1;
 366 }
 367
 368 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 369 {
 370         char *new_entry;
 371         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 372
 373         if (level == SMB_FIND_FILE_INFO_STANDARD) {
 374                 FIND_FILE_STANDARD_INFO *pfData;
 375                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 376
 377                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
 378                                 pfData->FileNameLength;
 379         } else
 380                 new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset);
 381         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 382         /* validate that new_entry is not past end of SMB */
 383         if (new_entry >= end_of_smb) {
 384                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 385                          new_entry, end_of_smb, old_entry);
 386                 return NULL;
 387         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 388                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
 389                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 390                    (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
 391                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 392                          new_entry, end_of_smb);
 393                 return NULL;
 394         } else
 395                 return new_entry;
 396
 397 }
 398
 399 struct cifs_dirent {
 400         const char      *name;
 401         size_t          namelen;
 402         u32             resume_key;
 403         u64             ino;
 404 };
 405
 406 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 407                 const FILE_UNIX_INFO *info, bool is_unicode)
 408 {
 409         de->name = &info->FileName[0];
 410         if (is_unicode)
 411                 de->namelen = cifs_unicode_bytelen(de->name);
 412         else
 413                 de->namelen = strnlen(de->name, PATH_MAX);
 414         de->resume_key = info->ResumeKey;
 415         de->ino = le64_to_cpu(info->basic.UniqueId);
 416 }
 417
 418 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 419                 const FILE_DIRECTORY_INFO *info)
 420 {
 421         de->name = &info->FileName[0];
 422         de->namelen = le32_to_cpu(info->FileNameLength);
 423         de->resume_key = info->FileIndex;
 424 }
 425
 426 static void cifs_fill_dirent_full(struct cifs_dirent *de,
 427                 const FILE_FULL_DIRECTORY_INFO *info)
 428 {
 429         de->name = &info->FileName[0];
 430         de->namelen = le32_to_cpu(info->FileNameLength);
 431         de->resume_key = info->FileIndex;
 432 }
 433
 434 static void cifs_fill_dirent_search(struct cifs_dirent *de,
 435                 const SEARCH_ID_FULL_DIR_INFO *info)
 436 {
 437         de->name = &info->FileName[0];
 438         de->namelen = le32_to_cpu(info->FileNameLength);
 439         de->resume_key = info->FileIndex;
 440         de->ino = le64_to_cpu(info->UniqueId);
 441 }
 442
 443 static void cifs_fill_dirent_both(struct cifs_dirent *de,
 444                 const FILE_BOTH_DIRECTORY_INFO *info)
 445 {
 446         de->name = &info->FileName[0];
 447         de->namelen = le32_to_cpu(info->FileNameLength);
 448         de->resume_key = info->FileIndex;
 449 }
 450
 451 static void cifs_fill_dirent_std(struct cifs_dirent *de,
 452                 const FIND_FILE_STANDARD_INFO *info)
 453 {
 454         de->name = &info->FileName[0];
 455         /* one byte length, no endianess conversion */
 456         de->namelen = info->FileNameLength;
 457         de->resume_key = info->ResumeKey;
 458 }
 459
 460 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 461                 u16 level, bool is_unicode)
 462 {
 463         memset(de, 0, sizeof(*de));
 464
 465         switch (level) {
 466         case SMB_FIND_FILE_UNIX:
 467                 cifs_fill_dirent_unix(de, info, is_unicode);
 468                 break;
 469         case SMB_FIND_FILE_DIRECTORY_INFO:
 470                 cifs_fill_dirent_dir(de, info);
 471                 break;
 472         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 473                 cifs_fill_dirent_full(de, info);
 474                 break;
 475         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 476                 cifs_fill_dirent_search(de, info);
 477                 break;
 478         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 479                 cifs_fill_dirent_both(de, info);
 480                 break;
 481         case SMB_FIND_FILE_INFO_STANDARD:
 482                 cifs_fill_dirent_std(de, info);
 483                 break;
 484         default:
 485                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 486                 return -EINVAL;
 487         }
 488
 489         return 0;
 490 }
 491
 492 #define UNICODE_DOT cpu_to_le16(0x2e)
 493
 494 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 495 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 496 {
 497         int rc = 0;
 498
 499         if (!de->name)
 500                 return 0;
 501
 502         if (is_unicode) {
 503                 __le16 *ufilename = (__le16 *)de->name;
 504                 if (de->namelen == 2) {
 505                         /* check for . */
 506                         if (ufilename[0] == UNICODE_DOT)
 507                                 rc = 1;
 508                 } else if (de->namelen == 4) {
 509                         /* check for .. */
 510                         if (ufilename[0] == UNICODE_DOT &&
 511                             ufilename[1] == UNICODE_DOT)
 512                                 rc = 2;
 513                 }
 514         } else /* ASCII */ {
 515                 if (de->namelen == 1) {
 516                         if (de->name[0] == '.')
 517                                 rc = 1;
 518                 } else if (de->namelen == 2) {
 519                         if (de->name[0] == '.' && de->name[1] == '.')
 520                                 rc = 2;
 521                 }
 522         }
 523
 524         return rc;
 525 }
 526
 527 /* Check if directory that we are searching has changed so we can decide
 528    whether we can use the cached search results from the previous search */
 529 static int is_dir_changed(struct file *file)
 530 {
 531         struct inode *inode = file_inode(file);
 532         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 533
 534         if (cifsInfo->time == 0)
 535                 return 1; /* directory was changed, perhaps due to unlink */
 536         else
 537                 return 0;
 538
 539 }
 540
 541 static int cifs_save_resume_key(const char *current_entry,
 542         struct cifsFileInfo *file_info)
 543 {
 544         struct cifs_dirent de;
 545         int rc;
 546
 547         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 548                               file_info->srch_inf.unicode);
 549         if (!rc) {
 550                 file_info->srch_inf.presume_name = de.name;
 551                 file_info->srch_inf.resume_name_len = de.namelen;
 552                 file_info->srch_inf.resume_key = de.resume_key;
 553         }
 554         return rc;
 555 }
 556
 557 /*
 558  * Find the corresponding entry in the search. Note that the SMB server returns
 559  * search entries for . and .. which complicates logic here if we choose to
 560  * parse for them and we do not assume that they are located in the findfirst
 561  * return buffer. We start counting in the buffer with entry 2 and increment for
 562  * every entry (do not increment for . or .. entry).
 563  */
 564 static int
 565 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
 566                 struct file *file, char **current_entry, int *num_to_ret)
 567 {
 568         __u16 search_flags;
 569         int rc = 0;
 570         int pos_in_buf = 0;
 571         loff_t first_entry_in_buffer;
 572         loff_t index_to_find = pos;
 573         struct cifsFileInfo *cfile = file->private_data;
 574         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 575         struct TCP_Server_Info *server = tcon->ses->server;
 576         /* check if index in the buffer */
 577
 578         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 579                 return -ENOSYS;
 580
 581         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 582                 return -ENOENT;
 583
 584         *current_entry = NULL;
 585         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 586                                         cfile->srch_inf.entries_in_buffer;
 587
 588         /*
 589          * If first entry in buf is zero then is first buffer
 590          * in search response data which means it is likely . and ..
 591          * will be in this buffer, although some servers do not return
 592          * . and .. for the root of a drive and for those we need
 593          * to start two entries earlier.
 594          */
 595
 596         dump_cifs_file_struct(file, "In fce ");
 597         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 598              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 599                 /* close and restart search */
 600                 cifs_dbg(FYI, "search backing up - close and restart search\n");
 601                 spin_lock(&cfile->file_info_lock);
 602                 if (server->ops->dir_needs_close(cfile)) {
 603                         cfile->invalidHandle = true;
 604                         spin_unlock(&cfile->file_info_lock);
 605                         if (server->ops->close_dir)
 606                                 server->ops->close_dir(xid, tcon, &cfile->fid);
 607                 } else
 608                         spin_unlock(&cfile->file_info_lock);
 609                 if (cfile->srch_inf.ntwrk_buf_start) {
 610                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 611                         if (cfile->srch_inf.smallBuf)
 612                                 cifs_small_buf_release(cfile->srch_inf.
 613                                                 ntwrk_buf_start);
 614                         else
 615                                 cifs_buf_release(cfile->srch_inf.
 616                                                 ntwrk_buf_start);
 617                         cfile->srch_inf.ntwrk_buf_start = NULL;
 618                 }
 619                 rc = initiate_cifs_search(xid, file);
 620                 if (rc) {
 621                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 622                                  rc);
 623                         return rc;
 624                 }
 625                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 626                 if (cfile->srch_inf.last_entry)
 627                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 628         }
 629
 630         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 631         if (backup_cred(cifs_sb))
 632                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 633
 634         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 635                (rc == 0) && !cfile->srch_inf.endOfSearch) {
 636                 cifs_dbg(FYI, "calling findnext2\n");
 637                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 638                                                  search_flags,
 639                                                  &cfile->srch_inf);
 640                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 641                 if (cfile->srch_inf.last_entry)
 642                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 643                 if (rc)
 644                         return -ENOENT;
 645         }
 646         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 647                 /* we found the buffer that contains the entry */
 648                 /* scan and find it */
 649                 int i;
 650                 char *cur_ent;
 651                 char *end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 652                         server->ops->calc_smb_size(
 653                                         cfile->srch_inf.ntwrk_buf_start);
 654
 655                 cur_ent = cfile->srch_inf.srch_entries_start;
 656                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 657                                         - cfile->srch_inf.entries_in_buffer;
 658                 pos_in_buf = index_to_find - first_entry_in_buffer;
 659                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 660
 661                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 662                         /* go entry by entry figuring out which is first */
 663                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 664                                                 cfile->srch_inf.info_level);
 665                 }
 666                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
 667                         /* BB fixme - check if we should flag this error */
 668                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 669                                  pos_in_buf, index_to_find, rc);
 670                 }
 671                 rc = 0;
 672                 *current_entry = cur_ent;
 673         } else {
 674                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 675                 return 0;
 676         }
 677
 678         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 679                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 680                 *num_to_ret = 0;
 681         } else
 682                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 683
 684         return rc;
 685 }
 686
 687 static int cifs_filldir(char *find_entry, struct file *file,
 688                 struct dir_context *ctx,
 689                 char *scratch_buf, unsigned int max_len)
 690 {
 691         struct cifsFileInfo *file_info = file->private_data;
 692         struct super_block *sb = file_inode(file)->i_sb;
 693         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 694         struct cifs_dirent de = { NULL, };
 695         struct cifs_fattr fattr;
 696         struct qstr name;
 697         int rc = 0;
 698         ino_t ino;
 699
 700         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 701                               file_info->srch_inf.unicode);
 702         if (rc)
 703                 return rc;
 704
 705         if (de.namelen > max_len) {
 706                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 707                          de.namelen);
 708                 return -EINVAL;
 709         }
 710
 711         /* skip . and .. since we added them first */
 712         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 713                 return 0;
 714
 715         if (file_info->srch_inf.unicode) {
 716                 struct nls_table *nlt = cifs_sb->local_nls;
 717                 int map_type;
 718
 719                 map_type = cifs_remap(cifs_sb);
 720                 name.name = scratch_buf;
 721                 name.len =
 722                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 723                                         UNICODE_NAME_MAX,
 724                                         min_t(size_t, de.namelen,
 725                                               (size_t)max_len), nlt, map_type);
 726                 name.len -= nls_nullsize(nlt);
 727         } else {
 728                 name.name = de.name;
 729                 name.len = de.namelen;
 730         }
 731
 732         switch (file_info->srch_inf.info_level) {
 733         case SMB_FIND_FILE_UNIX:
 734                 cifs_unix_basic_to_fattr(&fattr,
 735                                          &((FILE_UNIX_INFO *)find_entry)->basic,
 736                                          cifs_sb);
 737                 break;
 738         case SMB_FIND_FILE_INFO_STANDARD:
 739                 cifs_std_info_to_fattr(&fattr,
 740                                        (FIND_FILE_STANDARD_INFO *)find_entry,
 741                                        cifs_sb);
 742                 break;
 743         default:
 744                 cifs_dir_info_to_fattr(&fattr,
 745                                        (FILE_DIRECTORY_INFO *)find_entry,
 746                                        cifs_sb);
 747                 break;
 748         }
 749
 750         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 751                 fattr.cf_uniqueid = de.ino;
 752         } else {
 753                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
 754                 cifs_autodisable_serverino(cifs_sb);
 755         }
 756
 757         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
 758             couldbe_mf_symlink(&fattr))
 759                 /*
 760                  * trying to get the type and mode can be slow,
 761                  * so just call those regular files for now, and mark
 762                  * for reval
 763                  */
 764                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
 765
 766         cifs_prime_dcache(file_dentry(file), &name, &fattr);
 767
 768         ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
 769         return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
 770 }
 771
 772
 773 int cifs_readdir(struct file *file, struct dir_context *ctx)
 774 {
 775         int rc = 0;
 776         unsigned int xid;
 777         int i;
 778         struct cifs_tcon *tcon;
 779         struct cifsFileInfo *cifsFile = NULL;
 780         char *current_entry;
 781         int num_to_fill = 0;
 782         char *tmp_buf = NULL;
 783         char *end_of_smb;
 784         unsigned int max_len;
 785
 786         xid = get_xid();
 787
 788         /*
 789          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
 790          * '..'. Otherwise we won't be able to notify VFS in case of failure.
 791          */
 792         if (file->private_data == NULL) {
 793                 rc = initiate_cifs_search(xid, file);
 794                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
 795                 if (rc)
 796                         goto rddir2_exit;
 797         }
 798
 799         if (!dir_emit_dots(file, ctx))
 800                 goto rddir2_exit;
 801
 802         /* 1) If search is active,
 803                 is in current search buffer?
 804                 if it before then restart search
 805                 if after then keep searching till find it */
 806
 807         cifsFile = file->private_data;
 808         if (cifsFile->srch_inf.endOfSearch) {
 809                 if (cifsFile->srch_inf.emptyDir) {
 810                         cifs_dbg(FYI, "End of search, empty dir\n");
 811                         rc = 0;
 812                         goto rddir2_exit;
 813                 }
 814         } /* else {
 815                 cifsFile->invalidHandle = true;
 816                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
 817         } */
 818
 819         tcon = tlink_tcon(cifsFile->tlink);
 820         rc = find_cifs_entry(xid, tcon, ctx->pos, file, &current_entry,
 821                              &num_to_fill);
 822         if (rc) {
 823                 cifs_dbg(FYI, "fce error %d\n", rc);
 824                 goto rddir2_exit;
 825         } else if (current_entry != NULL) {
 826                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
 827         } else {
 828                 cifs_dbg(FYI, "could not find entry\n");
 829                 goto rddir2_exit;
 830         }
 831         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
 832                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
 833         max_len = tcon->ses->server->ops->calc_smb_size(
 834                         cifsFile->srch_inf.ntwrk_buf_start);
 835         end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
 836
 837         tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
 838         if (tmp_buf == NULL) {
 839                 rc = -ENOMEM;
 840                 goto rddir2_exit;
 841         }
 842
 843         for (i = 0; i < num_to_fill; i++) {
 844                 if (current_entry == NULL) {
 845                         /* evaluate whether this case is an error */
 846                         cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
 847                                  num_to_fill, i);
 848                         break;
 849                 }
 850                 /*
 851                  * if buggy server returns . and .. late do we want to
 852                  * check for that here?
 853                  */
 854                 *tmp_buf = 0;
 855                 rc = cifs_filldir(current_entry, file, ctx,
 856                                   tmp_buf, max_len);
 857                 if (rc) {
 858                         if (rc > 0)
 859                                 rc = 0;
 860                         break;
 861                 }
 862
 863                 ctx->pos++;
 864                 if (ctx->pos ==
 865                         cifsFile->srch_inf.index_of_last_entry) {
 866                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
 867                                  ctx->pos, tmp_buf);
 868                         cifs_save_resume_key(current_entry, cifsFile);
 869                         break;
 870                 } else
 871                         current_entry =
 872                                 nxt_dir_entry(current_entry, end_of_smb,
 873                                         cifsFile->srch_inf.info_level);
 874         }
 875         kfree(tmp_buf);
 876
 877 rddir2_exit:
 878         free_xid(xid);
 879         return rc;
 880 }