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 bool reparse_file_needs_reval(const struct cifs_fattr *fattr)
 143 {
 144         if (!(fattr->cf_cifsattrs & ATTR_REPARSE))
 145                 return false;
 146         /*
 147          * The DFS tags should be only intepreted by server side as per
 148          * MS-FSCC 2.1.2.1, but let's include them anyway.
 149          *
 150          * Besides, if cf_cifstag is unset (0), then we still need it to be
 151          * revalidated to know exactly what reparse point it is.
 152          */
 153         switch (fattr->cf_cifstag) {
 154         case IO_REPARSE_TAG_DFS:
 155         case IO_REPARSE_TAG_DFSR:
 156         case IO_REPARSE_TAG_SYMLINK:
 157         case IO_REPARSE_TAG_NFS:
 158         case 0:
 159                 return true;
 160         }
 161         return false;
 162 }
 163
 164 static void
 165 cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
 166 {
 167         fattr->cf_uid = cifs_sb->mnt_uid;
 168         fattr->cf_gid = cifs_sb->mnt_gid;
 169
 170         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 171                 fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
 172                 fattr->cf_dtype = DT_DIR;
 173         } else {
 174                 fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
 175                 fattr->cf_dtype = DT_REG;
 176         }
 177
 178         /*
 179          * We need to revalidate it further to make a decision about whether it
 180          * is a symbolic link, DFS referral or a reparse point with a direct
 181          * access like junctions, deduplicated files, NFS symlinks.
 182          */
 183         if (reparse_file_needs_reval(fattr))
 184                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 185
 186         /* non-unix readdir doesn't provide nlink */
 187         fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
 188
 189         if (fattr->cf_cifsattrs & ATTR_READONLY)
 190                 fattr->cf_mode &= ~S_IWUGO;
 191
 192         /*
 193          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
 194          * mark it for revalidation so that "ls -l" will look right. It might
 195          * be super-slow, but if we don't do this then the ownership of files
 196          * may look wrong since the inodes may not have timed out by the time
 197          * "ls" does a stat() call on them.
 198          */
 199         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL)
 200                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 201
 202         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
 203             fattr->cf_cifsattrs & ATTR_SYSTEM) {
 204                 if (fattr->cf_eof == 0)  {
 205                         fattr->cf_mode &= ~S_IFMT;
 206                         fattr->cf_mode |= S_IFIFO;
 207                         fattr->cf_dtype = DT_FIFO;
 208                 } else {
 209                         /*
 210                          * trying to get the type and mode via SFU can be slow,
 211                          * so just call those regular files for now, and mark
 212                          * for reval
 213                          */
 214                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 215                 }
 216         }
 217 }
 218
 219 static void __dir_info_to_fattr(struct cifs_fattr *fattr, const void *info)
 220 {
 221         const FILE_DIRECTORY_INFO *fi = info;
 222
 223         memset(fattr, 0, sizeof(*fattr));
 224         fattr->cf_cifsattrs = le32_to_cpu(fi->ExtFileAttributes);
 225         fattr->cf_eof = le64_to_cpu(fi->EndOfFile);
 226         fattr->cf_bytes = le64_to_cpu(fi->AllocationSize);
 227         fattr->cf_createtime = le64_to_cpu(fi->CreationTime);
 228         fattr->cf_atime = cifs_NTtimeToUnix(fi->LastAccessTime);
 229         fattr->cf_ctime = cifs_NTtimeToUnix(fi->ChangeTime);
 230         fattr->cf_mtime = cifs_NTtimeToUnix(fi->LastWriteTime);
 231 }
 232
 233 void
 234 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
 235                        struct cifs_sb_info *cifs_sb)
 236 {
 237         __dir_info_to_fattr(fattr, info);
 238         cifs_fill_common_info(fattr, cifs_sb);
 239 }
 240
 241 static void cifs_fulldir_info_to_fattr(struct cifs_fattr *fattr,
 242                                        SEARCH_ID_FULL_DIR_INFO *info,
 243                                        struct cifs_sb_info *cifs_sb)
 244 {
 245         __dir_info_to_fattr(fattr, info);
 246
 247         /* See MS-FSCC 2.4.18 FileIdFullDirectoryInformation */
 248         if (fattr->cf_cifsattrs & ATTR_REPARSE)
 249                 fattr->cf_cifstag = le32_to_cpu(info->EaSize);
 250         cifs_fill_common_info(fattr, cifs_sb);
 251 }
 252
 253 static void
 254 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 255                        struct cifs_sb_info *cifs_sb)
 256 {
 257         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 258
 259         memset(fattr, 0, sizeof(*fattr));
 260         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
 261                                             info->LastAccessTime, offset);
 262         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
 263                                             info->LastWriteTime, offset);
 264         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
 265                                             info->LastWriteTime, offset);
 266
 267         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
 268         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
 269         fattr->cf_eof = le32_to_cpu(info->DataSize);
 270
 271         cifs_fill_common_info(fattr, cifs_sb);
 272 }
 273
 274 /* BB eventually need to add the following helper function to
 275       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
 276       we try to do FindFirst on (NTFS) directory symlinks */
 277 /*
 278 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 279                              unsigned int xid)
 280 {
 281         __u16 fid;
 282         int len;
 283         int oplock = 0;
 284         int rc;
 285         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
 286         char *tmpbuffer;
 287
 288         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
 289                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 290                         cifs_sb->local_nls,
 291                         cifs_remap(cifs_sb);
 292         if (!rc) {
 293                 tmpbuffer = kmalloc(maxpath);
 294                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
 295                                 tmpbuffer,
 296                                 maxpath -1,
 297                                 fid,
 298                                 cifs_sb->local_nls);
 299                 if (CIFSSMBClose(xid, ptcon, fid)) {
 300                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
 301                 }
 302         }
 303 }
 304  */
 305
 306 static int
 307 initiate_cifs_search(const unsigned int xid, struct file *file)
 308 {
 309         __u16 search_flags;
 310         int rc = 0;
 311         char *full_path = NULL;
 312         struct cifsFileInfo *cifsFile;
 313         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 314         struct tcon_link *tlink = NULL;
 315         struct cifs_tcon *tcon;
 316         struct TCP_Server_Info *server;
 317
 318         if (file->private_data == NULL) {
 319                 tlink = cifs_sb_tlink(cifs_sb);
 320                 if (IS_ERR(tlink))
 321                         return PTR_ERR(tlink);
 322
 323                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 324                 if (cifsFile == NULL) {
 325                         rc = -ENOMEM;
 326                         goto error_exit;
 327                 }
 328                 spin_lock_init(&cifsFile->file_info_lock);
 329                 file->private_data = cifsFile;
 330                 cifsFile->tlink = cifs_get_tlink(tlink);
 331                 tcon = tlink_tcon(tlink);
 332         } else {
 333                 cifsFile = file->private_data;
 334                 tcon = tlink_tcon(cifsFile->tlink);
 335         }
 336
 337         server = tcon->ses->server;
 338
 339         if (!server->ops->query_dir_first) {
 340                 rc = -ENOSYS;
 341                 goto error_exit;
 342         }
 343
 344         cifsFile->invalidHandle = true;
 345         cifsFile->srch_inf.endOfSearch = false;
 346
 347         full_path = build_path_from_dentry(file_dentry(file));
 348         if (full_path == NULL) {
 349                 rc = -ENOMEM;
 350                 goto error_exit;
 351         }
 352
 353         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 354
 355 ffirst_retry:
 356         /* test for Unix extensions */
 357         /* but now check for them on the share/mount not on the SMB session */
 358         /* if (cap_unix(tcon->ses) { */
 359         if (tcon->unix_ext)
 360                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 361         else if ((tcon->ses->capabilities &
 362                   tcon->ses->server->vals->cap_nt_find) == 0) {
 363                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 364         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 365                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 366         } else /* not srvinos - BB fixme add check for backlevel? */ {
 367                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 368         }
 369
 370         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 371         if (backup_cred(cifs_sb))
 372                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 373
 374         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 375                                           &cifsFile->fid, search_flags,
 376                                           &cifsFile->srch_inf);
 377
 378         if (rc == 0)
 379                 cifsFile->invalidHandle = false;
 380         /* BB add following call to handle readdir on new NTFS symlink errors
 381         else if STATUS_STOPPED_ON_SYMLINK
 382                 call get_symlink_reparse_path and retry with new path */
 383         else if ((rc == -EOPNOTSUPP) &&
 384                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 385                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 386                 goto ffirst_retry;
 387         }
 388 error_exit:
 389         kfree(full_path);
 390         cifs_put_tlink(tlink);
 391         return rc;
 392 }
 393
 394 /* return length of unicode string in bytes */
 395 static int cifs_unicode_bytelen(const char *str)
 396 {
 397         int len;
 398         const __le16 *ustr = (const __le16 *)str;
 399
 400         for (len = 0; len <= PATH_MAX; len++) {
 401                 if (ustr[len] == 0)
 402                         return len << 1;
 403         }
 404         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 405         return len << 1;
 406 }
 407
 408 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 409 {
 410         char *new_entry;
 411         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 412
 413         if (level == SMB_FIND_FILE_INFO_STANDARD) {
 414                 FIND_FILE_STANDARD_INFO *pfData;
 415                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 416
 417                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
 418                                 pfData->FileNameLength;
 419         } else {
 420                 u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset);
 421
 422                 if (old_entry + next_offset < old_entry) {
 423                         cifs_dbg(VFS, "invalid offset %u\n", next_offset);
 424                         return NULL;
 425                 }
 426                 new_entry = old_entry + next_offset;
 427         }
 428         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 429         /* validate that new_entry is not past end of SMB */
 430         if (new_entry >= end_of_smb) {
 431                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 432                          new_entry, end_of_smb, old_entry);
 433                 return NULL;
 434         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 435                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
 436                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 437                    (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
 438                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 439                          new_entry, end_of_smb);
 440                 return NULL;
 441         } else
 442                 return new_entry;
 443
 444 }
 445
 446 struct cifs_dirent {
 447         const char      *name;
 448         size_t          namelen;
 449         u32             resume_key;
 450         u64             ino;
 451 };
 452
 453 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 454                 const FILE_UNIX_INFO *info, bool is_unicode)
 455 {
 456         de->name = &info->FileName[0];
 457         if (is_unicode)
 458                 de->namelen = cifs_unicode_bytelen(de->name);
 459         else
 460                 de->namelen = strnlen(de->name, PATH_MAX);
 461         de->resume_key = info->ResumeKey;
 462         de->ino = le64_to_cpu(info->basic.UniqueId);
 463 }
 464
 465 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 466                 const FILE_DIRECTORY_INFO *info)
 467 {
 468         de->name = &info->FileName[0];
 469         de->namelen = le32_to_cpu(info->FileNameLength);
 470         de->resume_key = info->FileIndex;
 471 }
 472
 473 static void cifs_fill_dirent_full(struct cifs_dirent *de,
 474                 const FILE_FULL_DIRECTORY_INFO *info)
 475 {
 476         de->name = &info->FileName[0];
 477         de->namelen = le32_to_cpu(info->FileNameLength);
 478         de->resume_key = info->FileIndex;
 479 }
 480
 481 static void cifs_fill_dirent_search(struct cifs_dirent *de,
 482                 const SEARCH_ID_FULL_DIR_INFO *info)
 483 {
 484         de->name = &info->FileName[0];
 485         de->namelen = le32_to_cpu(info->FileNameLength);
 486         de->resume_key = info->FileIndex;
 487         de->ino = le64_to_cpu(info->UniqueId);
 488 }
 489
 490 static void cifs_fill_dirent_both(struct cifs_dirent *de,
 491                 const FILE_BOTH_DIRECTORY_INFO *info)
 492 {
 493         de->name = &info->FileName[0];
 494         de->namelen = le32_to_cpu(info->FileNameLength);
 495         de->resume_key = info->FileIndex;
 496 }
 497
 498 static void cifs_fill_dirent_std(struct cifs_dirent *de,
 499                 const FIND_FILE_STANDARD_INFO *info)
 500 {
 501         de->name = &info->FileName[0];
 502         /* one byte length, no endianess conversion */
 503         de->namelen = info->FileNameLength;
 504         de->resume_key = info->ResumeKey;
 505 }
 506
 507 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 508                 u16 level, bool is_unicode)
 509 {
 510         memset(de, 0, sizeof(*de));
 511
 512         switch (level) {
 513         case SMB_FIND_FILE_UNIX:
 514                 cifs_fill_dirent_unix(de, info, is_unicode);
 515                 break;
 516         case SMB_FIND_FILE_DIRECTORY_INFO:
 517                 cifs_fill_dirent_dir(de, info);
 518                 break;
 519         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 520                 cifs_fill_dirent_full(de, info);
 521                 break;
 522         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 523                 cifs_fill_dirent_search(de, info);
 524                 break;
 525         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 526                 cifs_fill_dirent_both(de, info);
 527                 break;
 528         case SMB_FIND_FILE_INFO_STANDARD:
 529                 cifs_fill_dirent_std(de, info);
 530                 break;
 531         default:
 532                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 533                 return -EINVAL;
 534         }
 535
 536         return 0;
 537 }
 538
 539 #define UNICODE_DOT cpu_to_le16(0x2e)
 540
 541 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 542 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 543 {
 544         int rc = 0;
 545
 546         if (!de->name)
 547                 return 0;
 548
 549         if (is_unicode) {
 550                 __le16 *ufilename = (__le16 *)de->name;
 551                 if (de->namelen == 2) {
 552                         /* check for . */
 553                         if (ufilename[0] == UNICODE_DOT)
 554                                 rc = 1;
 555                 } else if (de->namelen == 4) {
 556                         /* check for .. */
 557                         if (ufilename[0] == UNICODE_DOT &&
 558                             ufilename[1] == UNICODE_DOT)
 559                                 rc = 2;
 560                 }
 561         } else /* ASCII */ {
 562                 if (de->namelen == 1) {
 563                         if (de->name[0] == '.')
 564                                 rc = 1;
 565                 } else if (de->namelen == 2) {
 566                         if (de->name[0] == '.' && de->name[1] == '.')
 567                                 rc = 2;
 568                 }
 569         }
 570
 571         return rc;
 572 }
 573
 574 /* Check if directory that we are searching has changed so we can decide
 575    whether we can use the cached search results from the previous search */
 576 static int is_dir_changed(struct file *file)
 577 {
 578         struct inode *inode = file_inode(file);
 579         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 580
 581         if (cifsInfo->time == 0)
 582                 return 1; /* directory was changed, perhaps due to unlink */
 583         else
 584                 return 0;
 585
 586 }
 587
 588 static int cifs_save_resume_key(const char *current_entry,
 589         struct cifsFileInfo *file_info)
 590 {
 591         struct cifs_dirent de;
 592         int rc;
 593
 594         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 595                               file_info->srch_inf.unicode);
 596         if (!rc) {
 597                 file_info->srch_inf.presume_name = de.name;
 598                 file_info->srch_inf.resume_name_len = de.namelen;
 599                 file_info->srch_inf.resume_key = de.resume_key;
 600         }
 601         return rc;
 602 }
 603
 604 /*
 605  * Find the corresponding entry in the search. Note that the SMB server returns
 606  * search entries for . and .. which complicates logic here if we choose to
 607  * parse for them and we do not assume that they are located in the findfirst
 608  * return buffer. We start counting in the buffer with entry 2 and increment for
 609  * every entry (do not increment for . or .. entry).
 610  */
 611 static int
 612 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
 613                 struct file *file, char **current_entry, int *num_to_ret)
 614 {
 615         __u16 search_flags;
 616         int rc = 0;
 617         int pos_in_buf = 0;
 618         loff_t first_entry_in_buffer;
 619         loff_t index_to_find = pos;
 620         struct cifsFileInfo *cfile = file->private_data;
 621         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 622         struct TCP_Server_Info *server = tcon->ses->server;
 623         /* check if index in the buffer */
 624
 625         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 626                 return -ENOSYS;
 627
 628         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 629                 return -ENOENT;
 630
 631         *current_entry = NULL;
 632         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 633                                         cfile->srch_inf.entries_in_buffer;
 634
 635         /*
 636          * If first entry in buf is zero then is first buffer
 637          * in search response data which means it is likely . and ..
 638          * will be in this buffer, although some servers do not return
 639          * . and .. for the root of a drive and for those we need
 640          * to start two entries earlier.
 641          */
 642
 643         dump_cifs_file_struct(file, "In fce ");
 644         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 645              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 646                 /* close and restart search */
 647                 cifs_dbg(FYI, "search backing up - close and restart search\n");
 648                 spin_lock(&cfile->file_info_lock);
 649                 if (server->ops->dir_needs_close(cfile)) {
 650                         cfile->invalidHandle = true;
 651                         spin_unlock(&cfile->file_info_lock);
 652                         if (server->ops->close_dir)
 653                                 server->ops->close_dir(xid, tcon, &cfile->fid);
 654                 } else
 655                         spin_unlock(&cfile->file_info_lock);
 656                 if (cfile->srch_inf.ntwrk_buf_start) {
 657                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 658                         if (cfile->srch_inf.smallBuf)
 659                                 cifs_small_buf_release(cfile->srch_inf.
 660                                                 ntwrk_buf_start);
 661                         else
 662                                 cifs_buf_release(cfile->srch_inf.
 663                                                 ntwrk_buf_start);
 664                         cfile->srch_inf.ntwrk_buf_start = NULL;
 665                 }
 666                 rc = initiate_cifs_search(xid, file);
 667                 if (rc) {
 668                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 669                                  rc);
 670                         return rc;
 671                 }
 672                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 673                 if (cfile->srch_inf.last_entry)
 674                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 675         }
 676
 677         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 678         if (backup_cred(cifs_sb))
 679                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 680
 681         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 682                (rc == 0) && !cfile->srch_inf.endOfSearch) {
 683                 cifs_dbg(FYI, "calling findnext2\n");
 684                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 685                                                  search_flags,
 686                                                  &cfile->srch_inf);
 687                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 688                 if (cfile->srch_inf.last_entry)
 689                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 690                 if (rc)
 691                         return -ENOENT;
 692         }
 693         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 694                 /* we found the buffer that contains the entry */
 695                 /* scan and find it */
 696                 int i;
 697                 char *cur_ent;
 698                 char *end_of_smb;
 699
 700                 if (cfile->srch_inf.ntwrk_buf_start == NULL) {
 701                         cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n");
 702                         return -EIO;
 703                 }
 704
 705                 end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 706                         server->ops->calc_smb_size(
 707                                         cfile->srch_inf.ntwrk_buf_start,
 708                                         server);
 709
 710                 cur_ent = cfile->srch_inf.srch_entries_start;
 711                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 712                                         - cfile->srch_inf.entries_in_buffer;
 713                 pos_in_buf = index_to_find - first_entry_in_buffer;
 714                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 715
 716                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 717                         /* go entry by entry figuring out which is first */
 718                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 719                                                 cfile->srch_inf.info_level);
 720                 }
 721                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
 722                         /* BB fixme - check if we should flag this error */
 723                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 724                                  pos_in_buf, index_to_find, rc);
 725                 }
 726                 rc = 0;
 727                 *current_entry = cur_ent;
 728         } else {
 729                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 730                 return 0;
 731         }
 732
 733         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 734                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 735                 *num_to_ret = 0;
 736         } else
 737                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 738
 739         return rc;
 740 }
 741
 742 static int cifs_filldir(char *find_entry, struct file *file,
 743                 struct dir_context *ctx,
 744                 char *scratch_buf, unsigned int max_len)
 745 {
 746         struct cifsFileInfo *file_info = file->private_data;
 747         struct super_block *sb = file_inode(file)->i_sb;
 748         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 749         struct cifs_dirent de = { NULL, };
 750         struct cifs_fattr fattr;
 751         struct qstr name;
 752         int rc = 0;
 753         ino_t ino;
 754
 755         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 756                               file_info->srch_inf.unicode);
 757         if (rc)
 758                 return rc;
 759
 760         if (de.namelen > max_len) {
 761                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 762                          de.namelen);
 763                 return -EINVAL;
 764         }
 765
 766         /* skip . and .. since we added them first */
 767         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 768                 return 0;
 769
 770         if (file_info->srch_inf.unicode) {
 771                 struct nls_table *nlt = cifs_sb->local_nls;
 772                 int map_type;
 773
 774                 map_type = cifs_remap(cifs_sb);
 775                 name.name = scratch_buf;
 776                 name.len =
 777                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 778                                         UNICODE_NAME_MAX,
 779                                         min_t(size_t, de.namelen,
 780                                               (size_t)max_len), nlt, map_type);
 781                 name.len -= nls_nullsize(nlt);
 782         } else {
 783                 name.name = de.name;
 784                 name.len = de.namelen;
 785         }
 786
 787         switch (file_info->srch_inf.info_level) {
 788         case SMB_FIND_FILE_UNIX:
 789                 cifs_unix_basic_to_fattr(&fattr,
 790                                          &((FILE_UNIX_INFO *)find_entry)->basic,
 791                                          cifs_sb);
 792                 break;
 793         case SMB_FIND_FILE_INFO_STANDARD:
 794                 cifs_std_info_to_fattr(&fattr,
 795                                        (FIND_FILE_STANDARD_INFO *)find_entry,
 796                                        cifs_sb);
 797                 break;
 798         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 799                 cifs_fulldir_info_to_fattr(&fattr,
 800                                            (SEARCH_ID_FULL_DIR_INFO *)find_entry,
 801                                            cifs_sb);
 802                 break;
 803         default:
 804                 cifs_dir_info_to_fattr(&fattr,
 805                                        (FILE_DIRECTORY_INFO *)find_entry,
 806                                        cifs_sb);
 807                 break;
 808         }
 809
 810         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 811                 fattr.cf_uniqueid = de.ino;
 812         } else {
 813                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
 814                 cifs_autodisable_serverino(cifs_sb);
 815         }
 816
 817         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
 818             couldbe_mf_symlink(&fattr))
 819                 /*
 820                  * trying to get the type and mode can be slow,
 821                  * so just call those regular files for now, and mark
 822                  * for reval
 823                  */
 824                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
 825
 826         cifs_prime_dcache(file_dentry(file), &name, &fattr);
 827
 828         ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
 829         return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
 830 }
 831
 832
 833 int cifs_readdir(struct file *file, struct dir_context *ctx)
 834 {
 835         int rc = 0;
 836         unsigned int xid;
 837         int i;
 838         struct cifs_tcon *tcon;
 839         struct cifsFileInfo *cifsFile = NULL;
 840         char *current_entry;
 841         int num_to_fill = 0;
 842         char *tmp_buf = NULL;
 843         char *end_of_smb;
 844         unsigned int max_len;
 845
 846         xid = get_xid();
 847
 848         /*
 849          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
 850          * '..'. Otherwise we won't be able to notify VFS in case of failure.
 851          */
 852         if (file->private_data == NULL) {
 853                 rc = initiate_cifs_search(xid, file);
 854                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
 855                 if (rc)
 856                         goto rddir2_exit;
 857         }
 858
 859         if (!dir_emit_dots(file, ctx))
 860                 goto rddir2_exit;
 861
 862         /* 1) If search is active,
 863                 is in current search buffer?
 864                 if it before then restart search
 865                 if after then keep searching till find it */
 866
 867         cifsFile = file->private_data;
 868         if (cifsFile->srch_inf.endOfSearch) {
 869                 if (cifsFile->srch_inf.emptyDir) {
 870                         cifs_dbg(FYI, "End of search, empty dir\n");
 871                         rc = 0;
 872                         goto rddir2_exit;
 873                 }
 874         } /* else {
 875                 cifsFile->invalidHandle = true;
 876                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
 877         } */
 878
 879         tcon = tlink_tcon(cifsFile->tlink);
 880         rc = find_cifs_entry(xid, tcon, ctx->pos, file, &current_entry,
 881                              &num_to_fill);
 882         if (rc) {
 883                 cifs_dbg(FYI, "fce error %d\n", rc);
 884                 goto rddir2_exit;
 885         } else if (current_entry != NULL) {
 886                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
 887         } else {
 888                 cifs_dbg(FYI, "could not find entry\n");
 889                 goto rddir2_exit;
 890         }
 891         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
 892                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
 893         max_len = tcon->ses->server->ops->calc_smb_size(
 894                         cifsFile->srch_inf.ntwrk_buf_start,
 895                         tcon->ses->server);
 896         end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
 897
 898         tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
 899         if (tmp_buf == NULL) {
 900                 rc = -ENOMEM;
 901                 goto rddir2_exit;
 902         }
 903
 904         for (i = 0; i < num_to_fill; i++) {
 905                 if (current_entry == NULL) {
 906                         /* evaluate whether this case is an error */
 907                         cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
 908                                  num_to_fill, i);
 909                         break;
 910                 }
 911                 /*
 912                  * if buggy server returns . and .. late do we want to
 913                  * check for that here?
 914                  */
 915                 *tmp_buf = 0;
 916                 rc = cifs_filldir(current_entry, file, ctx,
 917                                   tmp_buf, max_len);
 918                 if (rc) {
 919                         if (rc > 0)
 920                                 rc = 0;
 921                         break;
 922                 }
 923
 924                 ctx->pos++;
 925                 if (ctx->pos ==
 926                         cifsFile->srch_inf.index_of_last_entry) {
 927                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
 928                                  ctx->pos, tmp_buf);
 929                         cifs_save_resume_key(current_entry, cifsFile);
 930                         break;
 931                 } else
 932                         current_entry =
 933                                 nxt_dir_entry(current_entry, end_of_smb,
 934                                         cifsFile->srch_inf.info_level);
 935         }
 936         kfree(tmp_buf);
 937
 938 rddir2_exit:
 939         free_xid(xid);
 940         return rc;
 941 }