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 changed, then drop it and recreate it.
  73  */
  74 static void
  75 cifs_prime_dcache(struct dentry *parent, struct qstr *name,
  76                     struct cifs_fattr *fattr)
  77 {
  78         struct dentry *dentry, *alias;
  79         struct inode *inode;
  80         struct super_block *sb = parent->d_inode->i_sb;
  81         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
  82
  83         cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
  84
  85         dentry = d_hash_and_lookup(parent, name);
  86         if (unlikely(IS_ERR(dentry)))
  87                 return;
  88
  89         if (dentry) {
  90                 int err;
  91
  92                 inode = dentry->d_inode;
  93                 if (inode) {
  94                         /*
  95                          * If we're generating inode numbers, then we don't
  96                          * want to clobber the existing one with the one that
  97                          * the readdir code created.
  98                          */
  99                         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
 100                                 fattr->cf_uniqueid = CIFS_I(inode)->uniqueid;
 101
 102                         /* update inode in place if i_ino didn't change */
 103                         if (CIFS_I(inode)->uniqueid == fattr->cf_uniqueid) {
 104                                 cifs_fattr_to_inode(inode, fattr);
 105                                 goto out;
 106                         }
 107                 }
 108                 err = d_invalidate(dentry);
 109                 dput(dentry);
 110                 if (err)
 111                         return;
 112         }
 113
 114         dentry = d_alloc(parent, name);
 115         if (!dentry)
 116                 return;
 117
 118         inode = cifs_iget(sb, fattr);
 119         if (!inode)
 120                 goto out;
 121
 122         alias = d_materialise_unique(dentry, inode);
 123         if (alias && !IS_ERR(alias))
 124                 dput(alias);
 125 out:
 126         dput(dentry);
 127 }
 128
 129 /*
 130  * Is it possible that this directory might turn out to be a DFS referral
 131  * once we go to try and use it?
 132  */
 133 static bool
 134 cifs_dfs_is_possible(struct cifs_sb_info *cifs_sb)
 135 {
 136 #ifdef CONFIG_CIFS_DFS_UPCALL
 137         struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
 138
 139         if (tcon->Flags & SMB_SHARE_IS_IN_DFS)
 140                 return true;
 141 #endif
 142         return false;
 143 }
 144
 145 static void
 146 cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
 147 {
 148         fattr->cf_uid = cifs_sb->mnt_uid;
 149         fattr->cf_gid = cifs_sb->mnt_gid;
 150
 151         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 152                 fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
 153                 fattr->cf_dtype = DT_DIR;
 154                 /*
 155                  * Windows CIFS servers generally make DFS referrals look
 156                  * like directories in FIND_* responses with the reparse
 157                  * attribute flag also set (since DFS junctions are
 158                  * reparse points). We must revalidate at least these
 159                  * directory inodes before trying to use them (if
 160                  * they are DFS we will get PATH_NOT_COVERED back
 161                  * when queried directly and can then try to connect
 162                  * to the DFS target)
 163                  */
 164                 if (cifs_dfs_is_possible(cifs_sb) &&
 165                     (fattr->cf_cifsattrs & ATTR_REPARSE))
 166                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 167         } else {
 168                 fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
 169                 fattr->cf_dtype = DT_REG;
 170         }
 171
 172         if (fattr->cf_cifsattrs & ATTR_READONLY)
 173                 fattr->cf_mode &= ~S_IWUGO;
 174
 175         /*
 176          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
 177          * mark it for revalidation so that "ls -l" will look right. It might
 178          * be super-slow, but if we don't do this then the ownership of files
 179          * may look wrong since the inodes may not have timed out by the time
 180          * "ls" does a stat() call on them.
 181          */
 182         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL)
 183                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 184
 185         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
 186             fattr->cf_cifsattrs & ATTR_SYSTEM) {
 187                 if (fattr->cf_eof == 0)  {
 188                         fattr->cf_mode &= ~S_IFMT;
 189                         fattr->cf_mode |= S_IFIFO;
 190                         fattr->cf_dtype = DT_FIFO;
 191                 } else {
 192                         /*
 193                          * trying to get the type and mode via SFU can be slow,
 194                          * so just call those regular files for now, and mark
 195                          * for reval
 196                          */
 197                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 198                 }
 199         }
 200 }
 201
 202 void
 203 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
 204                        struct cifs_sb_info *cifs_sb)
 205 {
 206         memset(fattr, 0, sizeof(*fattr));
 207         fattr->cf_cifsattrs = le32_to_cpu(info->ExtFileAttributes);
 208         fattr->cf_eof = le64_to_cpu(info->EndOfFile);
 209         fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
 210         fattr->cf_createtime = le64_to_cpu(info->CreationTime);
 211         fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
 212         fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
 213         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
 214
 215         cifs_fill_common_info(fattr, cifs_sb);
 216 }
 217
 218 static void
 219 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 220                        struct cifs_sb_info *cifs_sb)
 221 {
 222         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 223
 224         memset(fattr, 0, sizeof(*fattr));
 225         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
 226                                             info->LastAccessTime, offset);
 227         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
 228                                             info->LastWriteTime, offset);
 229         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
 230                                             info->LastWriteTime, offset);
 231
 232         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
 233         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
 234         fattr->cf_eof = le32_to_cpu(info->DataSize);
 235
 236         cifs_fill_common_info(fattr, cifs_sb);
 237 }
 238
 239 /* BB eventually need to add the following helper function to
 240       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
 241       we try to do FindFirst on (NTFS) directory symlinks */
 242 /*
 243 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 244                              unsigned int xid)
 245 {
 246         __u16 fid;
 247         int len;
 248         int oplock = 0;
 249         int rc;
 250         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
 251         char *tmpbuffer;
 252
 253         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
 254                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 255                         cifs_sb->local_nls,
 256                         cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
 257         if (!rc) {
 258                 tmpbuffer = kmalloc(maxpath);
 259                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
 260                                 tmpbuffer,
 261                                 maxpath -1,
 262                                 fid,
 263                                 cifs_sb->local_nls);
 264                 if (CIFSSMBClose(xid, ptcon, fid)) {
 265                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
 266                 }
 267         }
 268 }
 269  */
 270
 271 static int
 272 initiate_cifs_search(const unsigned int xid, struct file *file)
 273 {
 274         __u16 search_flags;
 275         int rc = 0;
 276         char *full_path = NULL;
 277         struct cifsFileInfo *cifsFile;
 278         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 279         struct tcon_link *tlink = NULL;
 280         struct cifs_tcon *tcon;
 281         struct TCP_Server_Info *server;
 282
 283         if (file->private_data == NULL) {
 284                 tlink = cifs_sb_tlink(cifs_sb);
 285                 if (IS_ERR(tlink))
 286                         return PTR_ERR(tlink);
 287
 288                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 289                 if (cifsFile == NULL) {
 290                         rc = -ENOMEM;
 291                         goto error_exit;
 292                 }
 293                 file->private_data = cifsFile;
 294                 cifsFile->tlink = cifs_get_tlink(tlink);
 295                 tcon = tlink_tcon(tlink);
 296         } else {
 297                 cifsFile = file->private_data;
 298                 tcon = tlink_tcon(cifsFile->tlink);
 299         }
 300
 301         server = tcon->ses->server;
 302
 303         if (!server->ops->query_dir_first) {
 304                 rc = -ENOSYS;
 305                 goto error_exit;
 306         }
 307
 308         cifsFile->invalidHandle = true;
 309         cifsFile->srch_inf.endOfSearch = false;
 310
 311         full_path = build_path_from_dentry(file->f_path.dentry);
 312         if (full_path == NULL) {
 313                 rc = -ENOMEM;
 314                 goto error_exit;
 315         }
 316
 317         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 318
 319 ffirst_retry:
 320         /* test for Unix extensions */
 321         /* but now check for them on the share/mount not on the SMB session */
 322         /* if (cap_unix(tcon->ses) { */
 323         if (tcon->unix_ext)
 324                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 325         else if ((tcon->ses->capabilities &
 326                   tcon->ses->server->vals->cap_nt_find) == 0) {
 327                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 328         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 329                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 330         } else /* not srvinos - BB fixme add check for backlevel? */ {
 331                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 332         }
 333
 334         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 335         if (backup_cred(cifs_sb))
 336                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 337
 338         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 339                                           &cifsFile->fid, search_flags,
 340                                           &cifsFile->srch_inf);
 341
 342         if (rc == 0)
 343                 cifsFile->invalidHandle = false;
 344         /* BB add following call to handle readdir on new NTFS symlink errors
 345         else if STATUS_STOPPED_ON_SYMLINK
 346                 call get_symlink_reparse_path and retry with new path */
 347         else if ((rc == -EOPNOTSUPP) &&
 348                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 349                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 350                 goto ffirst_retry;
 351         }
 352 error_exit:
 353         kfree(full_path);
 354         cifs_put_tlink(tlink);
 355         return rc;
 356 }
 357
 358 /* return length of unicode string in bytes */
 359 static int cifs_unicode_bytelen(const char *str)
 360 {
 361         int len;
 362         const __le16 *ustr = (const __le16 *)str;
 363
 364         for (len = 0; len <= PATH_MAX; len++) {
 365                 if (ustr[len] == 0)
 366                         return len << 1;
 367         }
 368         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 369         return len << 1;
 370 }
 371
 372 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 373 {
 374         char *new_entry;
 375         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 376
 377         if (level == SMB_FIND_FILE_INFO_STANDARD) {
 378                 FIND_FILE_STANDARD_INFO *pfData;
 379                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 380
 381                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
 382                                 pfData->FileNameLength;
 383         } else
 384                 new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset);
 385         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 386         /* validate that new_entry is not past end of SMB */
 387         if (new_entry >= end_of_smb) {
 388                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 389                          new_entry, end_of_smb, old_entry);
 390                 return NULL;
 391         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 392                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
 393                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 394                    (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
 395                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 396                          new_entry, end_of_smb);
 397                 return NULL;
 398         } else
 399                 return new_entry;
 400
 401 }
 402
 403 struct cifs_dirent {
 404         const char      *name;
 405         size_t          namelen;
 406         u32             resume_key;
 407         u64             ino;
 408 };
 409
 410 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 411                 const FILE_UNIX_INFO *info, bool is_unicode)
 412 {
 413         de->name = &info->FileName[0];
 414         if (is_unicode)
 415                 de->namelen = cifs_unicode_bytelen(de->name);
 416         else
 417                 de->namelen = strnlen(de->name, PATH_MAX);
 418         de->resume_key = info->ResumeKey;
 419         de->ino = le64_to_cpu(info->basic.UniqueId);
 420 }
 421
 422 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 423                 const FILE_DIRECTORY_INFO *info)
 424 {
 425         de->name = &info->FileName[0];
 426         de->namelen = le32_to_cpu(info->FileNameLength);
 427         de->resume_key = info->FileIndex;
 428 }
 429
 430 static void cifs_fill_dirent_full(struct cifs_dirent *de,
 431                 const FILE_FULL_DIRECTORY_INFO *info)
 432 {
 433         de->name = &info->FileName[0];
 434         de->namelen = le32_to_cpu(info->FileNameLength);
 435         de->resume_key = info->FileIndex;
 436 }
 437
 438 static void cifs_fill_dirent_search(struct cifs_dirent *de,
 439                 const SEARCH_ID_FULL_DIR_INFO *info)
 440 {
 441         de->name = &info->FileName[0];
 442         de->namelen = le32_to_cpu(info->FileNameLength);
 443         de->resume_key = info->FileIndex;
 444         de->ino = le64_to_cpu(info->UniqueId);
 445 }
 446
 447 static void cifs_fill_dirent_both(struct cifs_dirent *de,
 448                 const FILE_BOTH_DIRECTORY_INFO *info)
 449 {
 450         de->name = &info->FileName[0];
 451         de->namelen = le32_to_cpu(info->FileNameLength);
 452         de->resume_key = info->FileIndex;
 453 }
 454
 455 static void cifs_fill_dirent_std(struct cifs_dirent *de,
 456                 const FIND_FILE_STANDARD_INFO *info)
 457 {
 458         de->name = &info->FileName[0];
 459         /* one byte length, no endianess conversion */
 460         de->namelen = info->FileNameLength;
 461         de->resume_key = info->ResumeKey;
 462 }
 463
 464 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 465                 u16 level, bool is_unicode)
 466 {
 467         memset(de, 0, sizeof(*de));
 468
 469         switch (level) {
 470         case SMB_FIND_FILE_UNIX:
 471                 cifs_fill_dirent_unix(de, info, is_unicode);
 472                 break;
 473         case SMB_FIND_FILE_DIRECTORY_INFO:
 474                 cifs_fill_dirent_dir(de, info);
 475                 break;
 476         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 477                 cifs_fill_dirent_full(de, info);
 478                 break;
 479         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 480                 cifs_fill_dirent_search(de, info);
 481                 break;
 482         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 483                 cifs_fill_dirent_both(de, info);
 484                 break;
 485         case SMB_FIND_FILE_INFO_STANDARD:
 486                 cifs_fill_dirent_std(de, info);
 487                 break;
 488         default:
 489                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 490                 return -EINVAL;
 491         }
 492
 493         return 0;
 494 }
 495
 496 #define UNICODE_DOT cpu_to_le16(0x2e)
 497
 498 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 499 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 500 {
 501         int rc = 0;
 502
 503         if (!de->name)
 504                 return 0;
 505
 506         if (is_unicode) {
 507                 __le16 *ufilename = (__le16 *)de->name;
 508                 if (de->namelen == 2) {
 509                         /* check for . */
 510                         if (ufilename[0] == UNICODE_DOT)
 511                                 rc = 1;
 512                 } else if (de->namelen == 4) {
 513                         /* check for .. */
 514                         if (ufilename[0] == UNICODE_DOT &&
 515                             ufilename[1] == UNICODE_DOT)
 516                                 rc = 2;
 517                 }
 518         } else /* ASCII */ {
 519                 if (de->namelen == 1) {
 520                         if (de->name[0] == '.')
 521                                 rc = 1;
 522                 } else if (de->namelen == 2) {
 523                         if (de->name[0] == '.' && de->name[1] == '.')
 524                                 rc = 2;
 525                 }
 526         }
 527
 528         return rc;
 529 }
 530
 531 /* Check if directory that we are searching has changed so we can decide
 532    whether we can use the cached search results from the previous search */
 533 static int is_dir_changed(struct file *file)
 534 {
 535         struct inode *inode = file_inode(file);
 536         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 537
 538         if (cifsInfo->time == 0)
 539                 return 1; /* directory was changed, perhaps due to unlink */
 540         else
 541                 return 0;
 542
 543 }
 544
 545 static int cifs_save_resume_key(const char *current_entry,
 546         struct cifsFileInfo *file_info)
 547 {
 548         struct cifs_dirent de;
 549         int rc;
 550
 551         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 552                               file_info->srch_inf.unicode);
 553         if (!rc) {
 554                 file_info->srch_inf.presume_name = de.name;
 555                 file_info->srch_inf.resume_name_len = de.namelen;
 556                 file_info->srch_inf.resume_key = de.resume_key;
 557         }
 558         return rc;
 559 }
 560
 561 /*
 562  * Find the corresponding entry in the search. Note that the SMB server returns
 563  * search entries for . and .. which complicates logic here if we choose to
 564  * parse for them and we do not assume that they are located in the findfirst
 565  * return buffer. We start counting in the buffer with entry 2 and increment for
 566  * every entry (do not increment for . or .. entry).
 567  */
 568 static int
 569 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
 570                 struct file *file, char **current_entry, int *num_to_ret)
 571 {
 572         __u16 search_flags;
 573         int rc = 0;
 574         int pos_in_buf = 0;
 575         loff_t first_entry_in_buffer;
 576         loff_t index_to_find = pos;
 577         struct cifsFileInfo *cfile = file->private_data;
 578         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 579         struct TCP_Server_Info *server = tcon->ses->server;
 580         /* check if index in the buffer */
 581
 582         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 583                 return -ENOSYS;
 584
 585         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 586                 return -ENOENT;
 587
 588         *current_entry = NULL;
 589         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 590                                         cfile->srch_inf.entries_in_buffer;
 591
 592         /*
 593          * If first entry in buf is zero then is first buffer
 594          * in search response data which means it is likely . and ..
 595          * will be in this buffer, although some servers do not return
 596          * . and .. for the root of a drive and for those we need
 597          * to start two entries earlier.
 598          */
 599
 600         dump_cifs_file_struct(file, "In fce ");
 601         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 602              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 603                 /* close and restart search */
 604                 cifs_dbg(FYI, "search backing up - close and restart search\n");
 605                 spin_lock(&cifs_file_list_lock);
 606                 if (!cfile->srch_inf.endOfSearch && !cfile->invalidHandle) {
 607                         cfile->invalidHandle = true;
 608                         spin_unlock(&cifs_file_list_lock);
 609                         if (server->ops->close)
 610                                 server->ops->close(xid, tcon, &cfile->fid);
 611                 } else
 612                         spin_unlock(&cifs_file_list_lock);
 613                 if (cfile->srch_inf.ntwrk_buf_start) {
 614                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 615                         if (cfile->srch_inf.smallBuf)
 616                                 cifs_small_buf_release(cfile->srch_inf.
 617                                                 ntwrk_buf_start);
 618                         else
 619                                 cifs_buf_release(cfile->srch_inf.
 620                                                 ntwrk_buf_start);
 621                         cfile->srch_inf.ntwrk_buf_start = NULL;
 622                 }
 623                 rc = initiate_cifs_search(xid, file);
 624                 if (rc) {
 625                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 626                                  rc);
 627                         return rc;
 628                 }
 629                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 630                 if (cfile->srch_inf.last_entry)
 631                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 632         }
 633
 634         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 635         if (backup_cred(cifs_sb))
 636                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 637
 638         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 639                (rc == 0) && !cfile->srch_inf.endOfSearch) {
 640                 cifs_dbg(FYI, "calling findnext2\n");
 641                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 642                                                  search_flags,
 643                                                  &cfile->srch_inf);
 644                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 645                 if (cfile->srch_inf.last_entry)
 646                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 647                 if (rc)
 648                         return -ENOENT;
 649         }
 650         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 651                 /* we found the buffer that contains the entry */
 652                 /* scan and find it */
 653                 int i;
 654                 char *cur_ent;
 655                 char *end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 656                         server->ops->calc_smb_size(
 657                                         cfile->srch_inf.ntwrk_buf_start);
 658
 659                 cur_ent = cfile->srch_inf.srch_entries_start;
 660                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 661                                         - cfile->srch_inf.entries_in_buffer;
 662                 pos_in_buf = index_to_find - first_entry_in_buffer;
 663                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 664
 665                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 666                         /* go entry by entry figuring out which is first */
 667                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 668                                                 cfile->srch_inf.info_level);
 669                 }
 670                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
 671                         /* BB fixme - check if we should flag this error */
 672                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 673                                  pos_in_buf, index_to_find, rc);
 674                 }
 675                 rc = 0;
 676                 *current_entry = cur_ent;
 677         } else {
 678                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 679                 return 0;
 680         }
 681
 682         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 683                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 684                 *num_to_ret = 0;
 685         } else
 686                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 687
 688         return rc;
 689 }
 690
 691 static int cifs_filldir(char *find_entry, struct file *file,
 692                 struct dir_context *ctx,
 693                 char *scratch_buf, unsigned int max_len)
 694 {
 695         struct cifsFileInfo *file_info = file->private_data;
 696         struct super_block *sb = file->f_path.dentry->d_sb;
 697         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 698         struct cifs_dirent de = { NULL, };
 699         struct cifs_fattr fattr;
 700         struct qstr name;
 701         int rc = 0;
 702         ino_t ino;
 703
 704         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 705                               file_info->srch_inf.unicode);
 706         if (rc)
 707                 return rc;
 708
 709         if (de.namelen > max_len) {
 710                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 711                          de.namelen);
 712                 return -EINVAL;
 713         }
 714
 715         /* skip . and .. since we added them first */
 716         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 717                 return 0;
 718
 719         if (file_info->srch_inf.unicode) {
 720                 struct nls_table *nlt = cifs_sb->local_nls;
 721
 722                 name.name = scratch_buf;
 723                 name.len =
 724                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 725                                         UNICODE_NAME_MAX,
 726                                         min_t(size_t, de.namelen,
 727                                               (size_t)max_len), nlt,
 728                                         cifs_sb->mnt_cifs_flags &
 729                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 730                 name.len -= nls_nullsize(nlt);
 731         } else {
 732                 name.name = de.name;
 733                 name.len = de.namelen;
 734         }
 735
 736         switch (file_info->srch_inf.info_level) {
 737         case SMB_FIND_FILE_UNIX:
 738                 cifs_unix_basic_to_fattr(&fattr,
 739                                          &((FILE_UNIX_INFO *)find_entry)->basic,
 740                                          cifs_sb);
 741                 break;
 742         case SMB_FIND_FILE_INFO_STANDARD:
 743                 cifs_std_info_to_fattr(&fattr,
 744                                        (FIND_FILE_STANDARD_INFO *)find_entry,
 745                                        cifs_sb);
 746                 break;
 747         default:
 748                 cifs_dir_info_to_fattr(&fattr,
 749                                        (FILE_DIRECTORY_INFO *)find_entry,
 750                                        cifs_sb);
 751                 break;
 752         }
 753
 754         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 755                 fattr.cf_uniqueid = de.ino;
 756         } else {
 757                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
 758                 cifs_autodisable_serverino(cifs_sb);
 759         }
 760
 761         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
 762             CIFSCouldBeMFSymlink(&fattr))
 763                 /*
 764                  * trying to get the type and mode can be slow,
 765                  * so just call those regular files for now, and mark
 766                  * for reval
 767                  */
 768                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
 769
 770         cifs_prime_dcache(file->f_dentry, &name, &fattr);
 771
 772         ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
 773         return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
 774 }
 775
 776
 777 int cifs_readdir(struct file *file, struct dir_context *ctx)
 778 {
 779         int rc = 0;
 780         unsigned int xid;
 781         int i;
 782         struct cifs_tcon *tcon;
 783         struct cifsFileInfo *cifsFile = NULL;
 784         char *current_entry;
 785         int num_to_fill = 0;
 786         char *tmp_buf = NULL;
 787         char *end_of_smb;
 788         unsigned int max_len;
 789
 790         xid = get_xid();
 791
 792         /*
 793          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
 794          * '..'. Otherwise we won't be able to notify VFS in case of failure.
 795          */
 796         if (file->private_data == NULL) {
 797                 rc = initiate_cifs_search(xid, file);
 798                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
 799                 if (rc)
 800                         goto rddir2_exit;
 801         }
 802
 803         if (!dir_emit_dots(file, ctx))
 804                 goto rddir2_exit;
 805
 806         /* 1) If search is active,
 807                 is in current search buffer?
 808                 if it before then restart search
 809                 if after then keep searching till find it */
 810
 811         if (file->private_data == NULL) {
 812                 rc = -EINVAL;
 813                 goto rddir2_exit;
 814         }
 815         cifsFile = file->private_data;
 816         if (cifsFile->srch_inf.endOfSearch) {
 817                 if (cifsFile->srch_inf.emptyDir) {
 818                         cifs_dbg(FYI, "End of search, empty dir\n");
 819                         rc = 0;
 820                         goto rddir2_exit;
 821                 }
 822         } /* else {
 823                 cifsFile->invalidHandle = true;
 824                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
 825         } */
 826
 827         tcon = tlink_tcon(cifsFile->tlink);
 828         rc = find_cifs_entry(xid, tcon, ctx->pos, file, &current_entry,
 829                              &num_to_fill);
 830         if (rc) {
 831                 cifs_dbg(FYI, "fce error %d\n", rc);
 832                 goto rddir2_exit;
 833         } else if (current_entry != NULL) {
 834                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
 835         } else {
 836                 cifs_dbg(FYI, "could not find entry\n");
 837                 goto rddir2_exit;
 838         }
 839         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
 840                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
 841         max_len = tcon->ses->server->ops->calc_smb_size(
 842                         cifsFile->srch_inf.ntwrk_buf_start);
 843         end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
 844
 845         tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
 846         if (tmp_buf == NULL) {
 847                 rc = -ENOMEM;
 848                 goto rddir2_exit;
 849         }
 850
 851         for (i = 0; i < num_to_fill; i++) {
 852                 if (current_entry == NULL) {
 853                         /* evaluate whether this case is an error */
 854                         cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
 855                                  num_to_fill, i);
 856                         break;
 857                 }
 858                 /*
 859                  * if buggy server returns . and .. late do we want to
 860                  * check for that here?
 861                  */
 862                 rc = cifs_filldir(current_entry, file, ctx,
 863                                   tmp_buf, max_len);
 864                 if (rc) {
 865                         if (rc > 0)
 866                                 rc = 0;
 867                         break;
 868                 }
 869
 870                 ctx->pos++;
 871                 if (ctx->pos ==
 872                         cifsFile->srch_inf.index_of_last_entry) {
 873                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
 874                                  ctx->pos, tmp_buf);
 875                         cifs_save_resume_key(current_entry, cifsFile);
 876                         break;
 877                 } else
 878                         current_entry =
 879                                 nxt_dir_entry(current_entry, end_of_smb,
 880                                         cifsFile->srch_inf.info_level);
 881         }
 882         kfree(tmp_buf);
 883
 884 rddir2_exit:
 885         free_xid(xid);
 886         return rc;
 887 }