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             (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID))
 201                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 202
 203         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
 204             fattr->cf_cifsattrs & ATTR_SYSTEM) {
 205                 if (fattr->cf_eof == 0)  {
 206                         fattr->cf_mode &= ~S_IFMT;
 207                         fattr->cf_mode |= S_IFIFO;
 208                         fattr->cf_dtype = DT_FIFO;
 209                 } else {
 210                         /*
 211                          * trying to get the type and mode via SFU can be slow,
 212                          * so just call those regular files for now, and mark
 213                          * for reval
 214                          */
 215                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 216                 }
 217         }
 218 }
 219
 220 static void __dir_info_to_fattr(struct cifs_fattr *fattr, const void *info)
 221 {
 222         const FILE_DIRECTORY_INFO *fi = info;
 223
 224         memset(fattr, 0, sizeof(*fattr));
 225         fattr->cf_cifsattrs = le32_to_cpu(fi->ExtFileAttributes);
 226         fattr->cf_eof = le64_to_cpu(fi->EndOfFile);
 227         fattr->cf_bytes = le64_to_cpu(fi->AllocationSize);
 228         fattr->cf_createtime = le64_to_cpu(fi->CreationTime);
 229         fattr->cf_atime = cifs_NTtimeToUnix(fi->LastAccessTime);
 230         fattr->cf_ctime = cifs_NTtimeToUnix(fi->ChangeTime);
 231         fattr->cf_mtime = cifs_NTtimeToUnix(fi->LastWriteTime);
 232 }
 233
 234 void
 235 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
 236                        struct cifs_sb_info *cifs_sb)
 237 {
 238         __dir_info_to_fattr(fattr, info);
 239         cifs_fill_common_info(fattr, cifs_sb);
 240 }
 241
 242 static void cifs_fulldir_info_to_fattr(struct cifs_fattr *fattr,
 243                                        SEARCH_ID_FULL_DIR_INFO *info,
 244                                        struct cifs_sb_info *cifs_sb)
 245 {
 246         __dir_info_to_fattr(fattr, info);
 247
 248         /* See MS-FSCC 2.4.18 FileIdFullDirectoryInformation */
 249         if (fattr->cf_cifsattrs & ATTR_REPARSE)
 250                 fattr->cf_cifstag = le32_to_cpu(info->EaSize);
 251         cifs_fill_common_info(fattr, cifs_sb);
 252 }
 253
 254 static void
 255 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 256                        struct cifs_sb_info *cifs_sb)
 257 {
 258         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 259
 260         memset(fattr, 0, sizeof(*fattr));
 261         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
 262                                             info->LastAccessTime, offset);
 263         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
 264                                             info->LastWriteTime, offset);
 265         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
 266                                             info->LastWriteTime, offset);
 267
 268         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
 269         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
 270         fattr->cf_eof = le32_to_cpu(info->DataSize);
 271
 272         cifs_fill_common_info(fattr, cifs_sb);
 273 }
 274
 275 /* BB eventually need to add the following helper function to
 276       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
 277       we try to do FindFirst on (NTFS) directory symlinks */
 278 /*
 279 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 280                              unsigned int xid)
 281 {
 282         __u16 fid;
 283         int len;
 284         int oplock = 0;
 285         int rc;
 286         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
 287         char *tmpbuffer;
 288
 289         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
 290                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 291                         cifs_sb->local_nls,
 292                         cifs_remap(cifs_sb);
 293         if (!rc) {
 294                 tmpbuffer = kmalloc(maxpath);
 295                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
 296                                 tmpbuffer,
 297                                 maxpath -1,
 298                                 fid,
 299                                 cifs_sb->local_nls);
 300                 if (CIFSSMBClose(xid, ptcon, fid)) {
 301                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
 302                 }
 303         }
 304 }
 305  */
 306
 307 static int
 308 initiate_cifs_search(const unsigned int xid, struct file *file)
 309 {
 310         __u16 search_flags;
 311         int rc = 0;
 312         char *full_path = NULL;
 313         struct cifsFileInfo *cifsFile;
 314         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 315         struct tcon_link *tlink = NULL;
 316         struct cifs_tcon *tcon;
 317         struct TCP_Server_Info *server;
 318
 319         if (file->private_data == NULL) {
 320                 tlink = cifs_sb_tlink(cifs_sb);
 321                 if (IS_ERR(tlink))
 322                         return PTR_ERR(tlink);
 323
 324                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 325                 if (cifsFile == NULL) {
 326                         rc = -ENOMEM;
 327                         goto error_exit;
 328                 }
 329                 spin_lock_init(&cifsFile->file_info_lock);
 330                 file->private_data = cifsFile;
 331                 cifsFile->tlink = cifs_get_tlink(tlink);
 332                 tcon = tlink_tcon(tlink);
 333         } else {
 334                 cifsFile = file->private_data;
 335                 tcon = tlink_tcon(cifsFile->tlink);
 336         }
 337
 338         server = tcon->ses->server;
 339
 340         if (!server->ops->query_dir_first) {
 341                 rc = -ENOSYS;
 342                 goto error_exit;
 343         }
 344
 345         cifsFile->invalidHandle = true;
 346         cifsFile->srch_inf.endOfSearch = false;
 347
 348         full_path = build_path_from_dentry(file_dentry(file));
 349         if (full_path == NULL) {
 350                 rc = -ENOMEM;
 351                 goto error_exit;
 352         }
 353
 354         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 355
 356 ffirst_retry:
 357         /* test for Unix extensions */
 358         /* but now check for them on the share/mount not on the SMB session */
 359         /* if (cap_unix(tcon->ses) { */
 360         if (tcon->unix_ext)
 361                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 362         else if ((tcon->ses->capabilities &
 363                   tcon->ses->server->vals->cap_nt_find) == 0) {
 364                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 365         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 366                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 367         } else /* not srvinos - BB fixme add check for backlevel? */ {
 368                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 369         }
 370
 371         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 372         if (backup_cred(cifs_sb))
 373                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 374
 375         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 376                                           &cifsFile->fid, search_flags,
 377                                           &cifsFile->srch_inf);
 378
 379         if (rc == 0)
 380                 cifsFile->invalidHandle = false;
 381         /* BB add following call to handle readdir on new NTFS symlink errors
 382         else if STATUS_STOPPED_ON_SYMLINK
 383                 call get_symlink_reparse_path and retry with new path */
 384         else if ((rc == -EOPNOTSUPP) &&
 385                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 386                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 387                 goto ffirst_retry;
 388         }
 389 error_exit:
 390         kfree(full_path);
 391         cifs_put_tlink(tlink);
 392         return rc;
 393 }
 394
 395 /* return length of unicode string in bytes */
 396 static int cifs_unicode_bytelen(const char *str)
 397 {
 398         int len;
 399         const __le16 *ustr = (const __le16 *)str;
 400
 401         for (len = 0; len <= PATH_MAX; len++) {
 402                 if (ustr[len] == 0)
 403                         return len << 1;
 404         }
 405         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 406         return len << 1;
 407 }
 408
 409 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 410 {
 411         char *new_entry;
 412         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 413
 414         if (level == SMB_FIND_FILE_INFO_STANDARD) {
 415                 FIND_FILE_STANDARD_INFO *pfData;
 416                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 417
 418                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
 419                                 pfData->FileNameLength;
 420         } else {
 421                 u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset);
 422
 423                 if (old_entry + next_offset < old_entry) {
 424                         cifs_dbg(VFS, "invalid offset %u\n", next_offset);
 425                         return NULL;
 426                 }
 427                 new_entry = old_entry + next_offset;
 428         }
 429         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 430         /* validate that new_entry is not past end of SMB */
 431         if (new_entry >= end_of_smb) {
 432                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 433                          new_entry, end_of_smb, old_entry);
 434                 return NULL;
 435         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 436                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
 437                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 438                    (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
 439                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 440                          new_entry, end_of_smb);
 441                 return NULL;
 442         } else
 443                 return new_entry;
 444
 445 }
 446
 447 struct cifs_dirent {
 448         const char      *name;
 449         size_t          namelen;
 450         u32             resume_key;
 451         u64             ino;
 452 };
 453
 454 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 455                 const FILE_UNIX_INFO *info, bool is_unicode)
 456 {
 457         de->name = &info->FileName[0];
 458         if (is_unicode)
 459                 de->namelen = cifs_unicode_bytelen(de->name);
 460         else
 461                 de->namelen = strnlen(de->name, PATH_MAX);
 462         de->resume_key = info->ResumeKey;
 463         de->ino = le64_to_cpu(info->basic.UniqueId);
 464 }
 465
 466 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 467                 const FILE_DIRECTORY_INFO *info)
 468 {
 469         de->name = &info->FileName[0];
 470         de->namelen = le32_to_cpu(info->FileNameLength);
 471         de->resume_key = info->FileIndex;
 472 }
 473
 474 static void cifs_fill_dirent_full(struct cifs_dirent *de,
 475                 const FILE_FULL_DIRECTORY_INFO *info)
 476 {
 477         de->name = &info->FileName[0];
 478         de->namelen = le32_to_cpu(info->FileNameLength);
 479         de->resume_key = info->FileIndex;
 480 }
 481
 482 static void cifs_fill_dirent_search(struct cifs_dirent *de,
 483                 const SEARCH_ID_FULL_DIR_INFO *info)
 484 {
 485         de->name = &info->FileName[0];
 486         de->namelen = le32_to_cpu(info->FileNameLength);
 487         de->resume_key = info->FileIndex;
 488         de->ino = le64_to_cpu(info->UniqueId);
 489 }
 490
 491 static void cifs_fill_dirent_both(struct cifs_dirent *de,
 492                 const FILE_BOTH_DIRECTORY_INFO *info)
 493 {
 494         de->name = &info->FileName[0];
 495         de->namelen = le32_to_cpu(info->FileNameLength);
 496         de->resume_key = info->FileIndex;
 497 }
 498
 499 static void cifs_fill_dirent_std(struct cifs_dirent *de,
 500                 const FIND_FILE_STANDARD_INFO *info)
 501 {
 502         de->name = &info->FileName[0];
 503         /* one byte length, no endianess conversion */
 504         de->namelen = info->FileNameLength;
 505         de->resume_key = info->ResumeKey;
 506 }
 507
 508 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 509                 u16 level, bool is_unicode)
 510 {
 511         memset(de, 0, sizeof(*de));
 512
 513         switch (level) {
 514         case SMB_FIND_FILE_UNIX:
 515                 cifs_fill_dirent_unix(de, info, is_unicode);
 516                 break;
 517         case SMB_FIND_FILE_DIRECTORY_INFO:
 518                 cifs_fill_dirent_dir(de, info);
 519                 break;
 520         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 521                 cifs_fill_dirent_full(de, info);
 522                 break;
 523         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 524                 cifs_fill_dirent_search(de, info);
 525                 break;
 526         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 527                 cifs_fill_dirent_both(de, info);
 528                 break;
 529         case SMB_FIND_FILE_INFO_STANDARD:
 530                 cifs_fill_dirent_std(de, info);
 531                 break;
 532         default:
 533                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 534                 return -EINVAL;
 535         }
 536
 537         return 0;
 538 }
 539
 540 #define UNICODE_DOT cpu_to_le16(0x2e)
 541
 542 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 543 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 544 {
 545         int rc = 0;
 546
 547         if (!de->name)
 548                 return 0;
 549
 550         if (is_unicode) {
 551                 __le16 *ufilename = (__le16 *)de->name;
 552                 if (de->namelen == 2) {
 553                         /* check for . */
 554                         if (ufilename[0] == UNICODE_DOT)
 555                                 rc = 1;
 556                 } else if (de->namelen == 4) {
 557                         /* check for .. */
 558                         if (ufilename[0] == UNICODE_DOT &&
 559                             ufilename[1] == UNICODE_DOT)
 560                                 rc = 2;
 561                 }
 562         } else /* ASCII */ {
 563                 if (de->namelen == 1) {
 564                         if (de->name[0] == '.')
 565                                 rc = 1;
 566                 } else if (de->namelen == 2) {
 567                         if (de->name[0] == '.' && de->name[1] == '.')
 568                                 rc = 2;
 569                 }
 570         }
 571
 572         return rc;
 573 }
 574
 575 /* Check if directory that we are searching has changed so we can decide
 576    whether we can use the cached search results from the previous search */
 577 static int is_dir_changed(struct file *file)
 578 {
 579         struct inode *inode = file_inode(file);
 580         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 581
 582         if (cifsInfo->time == 0)
 583                 return 1; /* directory was changed, perhaps due to unlink */
 584         else
 585                 return 0;
 586
 587 }
 588
 589 static int cifs_save_resume_key(const char *current_entry,
 590         struct cifsFileInfo *file_info)
 591 {
 592         struct cifs_dirent de;
 593         int rc;
 594
 595         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 596                               file_info->srch_inf.unicode);
 597         if (!rc) {
 598                 file_info->srch_inf.presume_name = de.name;
 599                 file_info->srch_inf.resume_name_len = de.namelen;
 600                 file_info->srch_inf.resume_key = de.resume_key;
 601         }
 602         return rc;
 603 }
 604
 605 /*
 606  * Find the corresponding entry in the search. Note that the SMB server returns
 607  * search entries for . and .. which complicates logic here if we choose to
 608  * parse for them and we do not assume that they are located in the findfirst
 609  * return buffer. We start counting in the buffer with entry 2 and increment for
 610  * every entry (do not increment for . or .. entry).
 611  */
 612 static int
 613 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
 614                 struct file *file, char **current_entry, int *num_to_ret)
 615 {
 616         __u16 search_flags;
 617         int rc = 0;
 618         int pos_in_buf = 0;
 619         loff_t first_entry_in_buffer;
 620         loff_t index_to_find = pos;
 621         struct cifsFileInfo *cfile = file->private_data;
 622         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 623         struct TCP_Server_Info *server = tcon->ses->server;
 624         /* check if index in the buffer */
 625
 626         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 627                 return -ENOSYS;
 628
 629         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 630                 return -ENOENT;
 631
 632         *current_entry = NULL;
 633         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 634                                         cfile->srch_inf.entries_in_buffer;
 635
 636         /*
 637          * If first entry in buf is zero then is first buffer
 638          * in search response data which means it is likely . and ..
 639          * will be in this buffer, although some servers do not return
 640          * . and .. for the root of a drive and for those we need
 641          * to start two entries earlier.
 642          */
 643
 644         dump_cifs_file_struct(file, "In fce ");
 645         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 646              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 647                 /* close and restart search */
 648                 cifs_dbg(FYI, "search backing up - close and restart search\n");
 649                 spin_lock(&cfile->file_info_lock);
 650                 if (server->ops->dir_needs_close(cfile)) {
 651                         cfile->invalidHandle = true;
 652                         spin_unlock(&cfile->file_info_lock);
 653                         if (server->ops->close_dir)
 654                                 server->ops->close_dir(xid, tcon, &cfile->fid);
 655                 } else
 656                         spin_unlock(&cfile->file_info_lock);
 657                 if (cfile->srch_inf.ntwrk_buf_start) {
 658                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 659                         if (cfile->srch_inf.smallBuf)
 660                                 cifs_small_buf_release(cfile->srch_inf.
 661                                                 ntwrk_buf_start);
 662                         else
 663                                 cifs_buf_release(cfile->srch_inf.
 664                                                 ntwrk_buf_start);
 665                         cfile->srch_inf.ntwrk_buf_start = NULL;
 666                 }
 667                 rc = initiate_cifs_search(xid, file);
 668                 if (rc) {
 669                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 670                                  rc);
 671                         return rc;
 672                 }
 673                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 674                 if (cfile->srch_inf.last_entry)
 675                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 676         }
 677
 678         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 679         if (backup_cred(cifs_sb))
 680                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 681
 682         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 683                (rc == 0) && !cfile->srch_inf.endOfSearch) {
 684                 cifs_dbg(FYI, "calling findnext2\n");
 685                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 686                                                  search_flags,
 687                                                  &cfile->srch_inf);
 688                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 689                 if (cfile->srch_inf.last_entry)
 690                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 691                 if (rc)
 692                         return -ENOENT;
 693         }
 694         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 695                 /* we found the buffer that contains the entry */
 696                 /* scan and find it */
 697                 int i;
 698                 char *cur_ent;
 699                 char *end_of_smb;
 700
 701                 if (cfile->srch_inf.ntwrk_buf_start == NULL) {
 702                         cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n");
 703                         return -EIO;
 704                 }
 705
 706                 end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 707                         server->ops->calc_smb_size(
 708                                         cfile->srch_inf.ntwrk_buf_start,
 709                                         server);
 710
 711                 cur_ent = cfile->srch_inf.srch_entries_start;
 712                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 713                                         - cfile->srch_inf.entries_in_buffer;
 714                 pos_in_buf = index_to_find - first_entry_in_buffer;
 715                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 716
 717                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 718                         /* go entry by entry figuring out which is first */
 719                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 720                                                 cfile->srch_inf.info_level);
 721                 }
 722                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
 723                         /* BB fixme - check if we should flag this error */
 724                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 725                                  pos_in_buf, index_to_find, rc);
 726                 }
 727                 rc = 0;
 728                 *current_entry = cur_ent;
 729         } else {
 730                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 731                 return 0;
 732         }
 733
 734         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 735                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 736                 *num_to_ret = 0;
 737         } else
 738                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 739
 740         return rc;
 741 }
 742
 743 static int cifs_filldir(char *find_entry, struct file *file,
 744                 struct dir_context *ctx,
 745                 char *scratch_buf, unsigned int max_len)
 746 {
 747         struct cifsFileInfo *file_info = file->private_data;
 748         struct super_block *sb = file_inode(file)->i_sb;
 749         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 750         struct cifs_dirent de = { NULL, };
 751         struct cifs_fattr fattr;
 752         struct qstr name;
 753         int rc = 0;
 754         ino_t ino;
 755
 756         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 757                               file_info->srch_inf.unicode);
 758         if (rc)
 759                 return rc;
 760
 761         if (de.namelen > max_len) {
 762                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 763                          de.namelen);
 764                 return -EINVAL;
 765         }
 766
 767         /* skip . and .. since we added them first */
 768         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 769                 return 0;
 770
 771         if (file_info->srch_inf.unicode) {
 772                 struct nls_table *nlt = cifs_sb->local_nls;
 773                 int map_type;
 774
 775                 map_type = cifs_remap(cifs_sb);
 776                 name.name = scratch_buf;
 777                 name.len =
 778                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 779                                         UNICODE_NAME_MAX,
 780                                         min_t(size_t, de.namelen,
 781                                               (size_t)max_len), nlt, map_type);
 782                 name.len -= nls_nullsize(nlt);
 783         } else {
 784                 name.name = de.name;
 785                 name.len = de.namelen;
 786         }
 787
 788         switch (file_info->srch_inf.info_level) {
 789         case SMB_FIND_FILE_UNIX:
 790                 cifs_unix_basic_to_fattr(&fattr,
 791                                          &((FILE_UNIX_INFO *)find_entry)->basic,
 792                                          cifs_sb);
 793                 break;
 794         case SMB_FIND_FILE_INFO_STANDARD:
 795                 cifs_std_info_to_fattr(&fattr,
 796                                        (FIND_FILE_STANDARD_INFO *)find_entry,
 797                                        cifs_sb);
 798                 break;
 799         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 800                 cifs_fulldir_info_to_fattr(&fattr,
 801                                            (SEARCH_ID_FULL_DIR_INFO *)find_entry,
 802                                            cifs_sb);
 803                 break;
 804         default:
 805                 cifs_dir_info_to_fattr(&fattr,
 806                                        (FILE_DIRECTORY_INFO *)find_entry,
 807                                        cifs_sb);
 808                 break;
 809         }
 810
 811         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 812                 fattr.cf_uniqueid = de.ino;
 813         } else {
 814                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
 815                 cifs_autodisable_serverino(cifs_sb);
 816         }
 817
 818         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
 819             couldbe_mf_symlink(&fattr))
 820                 /*
 821                  * trying to get the type and mode can be slow,
 822                  * so just call those regular files for now, and mark
 823                  * for reval
 824                  */
 825                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
 826
 827         cifs_prime_dcache(file_dentry(file), &name, &fattr);
 828
 829         ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
 830         return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
 831 }
 832
 833
 834 int cifs_readdir(struct file *file, struct dir_context *ctx)
 835 {
 836         int rc = 0;
 837         unsigned int xid;
 838         int i;
 839         struct cifs_tcon *tcon;
 840         struct cifsFileInfo *cifsFile = NULL;
 841         char *current_entry;
 842         int num_to_fill = 0;
 843         char *tmp_buf = NULL;
 844         char *end_of_smb;
 845         unsigned int max_len;
 846
 847         xid = get_xid();
 848
 849         /*
 850          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
 851          * '..'. Otherwise we won't be able to notify VFS in case of failure.
 852          */
 853         if (file->private_data == NULL) {
 854                 rc = initiate_cifs_search(xid, file);
 855                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
 856                 if (rc)
 857                         goto rddir2_exit;
 858         }
 859
 860         if (!dir_emit_dots(file, ctx))
 861                 goto rddir2_exit;
 862
 863         /* 1) If search is active,
 864                 is in current search buffer?
 865                 if it before then restart search
 866                 if after then keep searching till find it */
 867
 868         cifsFile = file->private_data;
 869         if (cifsFile->srch_inf.endOfSearch) {
 870                 if (cifsFile->srch_inf.emptyDir) {
 871                         cifs_dbg(FYI, "End of search, empty dir\n");
 872                         rc = 0;
 873                         goto rddir2_exit;
 874                 }
 875         } /* else {
 876                 cifsFile->invalidHandle = true;
 877                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
 878         } */
 879
 880         tcon = tlink_tcon(cifsFile->tlink);
 881         rc = find_cifs_entry(xid, tcon, ctx->pos, file, &current_entry,
 882                              &num_to_fill);
 883         if (rc) {
 884                 cifs_dbg(FYI, "fce error %d\n", rc);
 885                 goto rddir2_exit;
 886         } else if (current_entry != NULL) {
 887                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
 888         } else {
 889                 cifs_dbg(FYI, "could not find entry\n");
 890                 goto rddir2_exit;
 891         }
 892         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
 893                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
 894         max_len = tcon->ses->server->ops->calc_smb_size(
 895                         cifsFile->srch_inf.ntwrk_buf_start,
 896                         tcon->ses->server);
 897         end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
 898
 899         tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
 900         if (tmp_buf == NULL) {
 901                 rc = -ENOMEM;
 902                 goto rddir2_exit;
 903         }
 904
 905         for (i = 0; i < num_to_fill; i++) {
 906                 if (current_entry == NULL) {
 907                         /* evaluate whether this case is an error */
 908                         cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
 909                                  num_to_fill, i);
 910                         break;
 911                 }
 912                 /*
 913                  * if buggy server returns . and .. late do we want to
 914                  * check for that here?
 915                  */
 916                 *tmp_buf = 0;
 917                 rc = cifs_filldir(current_entry, file, ctx,
 918                                   tmp_buf, max_len);
 919                 if (rc) {
 920                         if (rc > 0)
 921                                 rc = 0;
 922                         break;
 923                 }
 924
 925                 ctx->pos++;
 926                 if (ctx->pos ==
 927                         cifsFile->srch_inf.index_of_last_entry) {
 928                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
 929                                  ctx->pos, tmp_buf);
 930                         cifs_save_resume_key(current_entry, cifsFile);
 931                         break;
 932                 } else
 933                         current_entry =
 934                                 nxt_dir_entry(current_entry, end_of_smb,
 935                                         cifsFile->srch_inf.info_level);
 936         }
 937         kfree(tmp_buf);
 938
 939 rddir2_exit:
 940         free_xid(xid);
 941         return rc;
 942 }