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         /*
 115          * If we know that the inode will need to be revalidated immediately,
 116          * then don't create a new dentry for it. We'll end up doing an on
 117          * the wire call either way and this spares us an invalidation.
 118          */
 119         if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
 120                 return;
 121
 122         dentry = d_alloc(parent, name);
 123         if (!dentry)
 124                 return;
 125
 126         inode = cifs_iget(sb, fattr);
 127         if (!inode)
 128                 goto out;
 129
 130         alias = d_materialise_unique(dentry, inode);
 131         if (alias && !IS_ERR(alias))
 132                 dput(alias);
 133 out:
 134         dput(dentry);
 135 }
 136
 137 /*
 138  * Is it possible that this directory might turn out to be a DFS referral
 139  * once we go to try and use it?
 140  */
 141 static bool
 142 cifs_dfs_is_possible(struct cifs_sb_info *cifs_sb)
 143 {
 144 #ifdef CONFIG_CIFS_DFS_UPCALL
 145         struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
 146
 147         if (tcon->Flags & SMB_SHARE_IS_IN_DFS)
 148                 return true;
 149 #endif
 150         return false;
 151 }
 152
 153 static void
 154 cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
 155 {
 156         fattr->cf_uid = cifs_sb->mnt_uid;
 157         fattr->cf_gid = cifs_sb->mnt_gid;
 158
 159         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 160                 fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
 161                 fattr->cf_dtype = DT_DIR;
 162                 /*
 163                  * Windows CIFS servers generally make DFS referrals look
 164                  * like directories in FIND_* responses with the reparse
 165                  * attribute flag also set (since DFS junctions are
 166                  * reparse points). We must revalidate at least these
 167                  * directory inodes before trying to use them (if
 168                  * they are DFS we will get PATH_NOT_COVERED back
 169                  * when queried directly and can then try to connect
 170                  * to the DFS target)
 171                  */
 172                 if (cifs_dfs_is_possible(cifs_sb) &&
 173                     (fattr->cf_cifsattrs & ATTR_REPARSE))
 174                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 175         } else if (fattr->cf_cifsattrs & ATTR_REPARSE) {
 176                 fattr->cf_mode = S_IFLNK;
 177                 fattr->cf_dtype = DT_LNK;
 178         } else {
 179                 fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
 180                 fattr->cf_dtype = DT_REG;
 181         }
 182
 183         if (fattr->cf_cifsattrs & ATTR_READONLY)
 184                 fattr->cf_mode &= ~S_IWUGO;
 185
 186         /*
 187          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
 188          * mark it for revalidation so that "ls -l" will look right. It might
 189          * be super-slow, but if we don't do this then the ownership of files
 190          * may look wrong since the inodes may not have timed out by the time
 191          * "ls" does a stat() call on them.
 192          */
 193         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL)
 194                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 195
 196         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
 197             fattr->cf_cifsattrs & ATTR_SYSTEM) {
 198                 if (fattr->cf_eof == 0)  {
 199                         fattr->cf_mode &= ~S_IFMT;
 200                         fattr->cf_mode |= S_IFIFO;
 201                         fattr->cf_dtype = DT_FIFO;
 202                 } else {
 203                         /*
 204                          * trying to get the type and mode via SFU can be slow,
 205                          * so just call those regular files for now, and mark
 206                          * for reval
 207                          */
 208                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 209                 }
 210         }
 211 }
 212
 213 void
 214 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
 215                        struct cifs_sb_info *cifs_sb)
 216 {
 217         memset(fattr, 0, sizeof(*fattr));
 218         fattr->cf_cifsattrs = le32_to_cpu(info->ExtFileAttributes);
 219         fattr->cf_eof = le64_to_cpu(info->EndOfFile);
 220         fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
 221         fattr->cf_createtime = le64_to_cpu(info->CreationTime);
 222         fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
 223         fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
 224         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
 225
 226         cifs_fill_common_info(fattr, cifs_sb);
 227 }
 228
 229 static void
 230 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 231                        struct cifs_sb_info *cifs_sb)
 232 {
 233         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 234
 235         memset(fattr, 0, sizeof(*fattr));
 236         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
 237                                             info->LastAccessTime, offset);
 238         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
 239                                             info->LastWriteTime, offset);
 240         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
 241                                             info->LastWriteTime, offset);
 242
 243         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
 244         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
 245         fattr->cf_eof = le32_to_cpu(info->DataSize);
 246
 247         cifs_fill_common_info(fattr, cifs_sb);
 248 }
 249
 250 /* BB eventually need to add the following helper function to
 251       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
 252       we try to do FindFirst on (NTFS) directory symlinks */
 253 /*
 254 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 255                              unsigned int xid)
 256 {
 257         __u16 fid;
 258         int len;
 259         int oplock = 0;
 260         int rc;
 261         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
 262         char *tmpbuffer;
 263
 264         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
 265                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 266                         cifs_sb->local_nls,
 267                         cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
 268         if (!rc) {
 269                 tmpbuffer = kmalloc(maxpath);
 270                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
 271                                 tmpbuffer,
 272                                 maxpath -1,
 273                                 fid,
 274                                 cifs_sb->local_nls);
 275                 if (CIFSSMBClose(xid, ptcon, fid)) {
 276                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
 277                 }
 278         }
 279 }
 280  */
 281
 282 static int
 283 initiate_cifs_search(const unsigned int xid, struct file *file)
 284 {
 285         __u16 search_flags;
 286         int rc = 0;
 287         char *full_path = NULL;
 288         struct cifsFileInfo *cifsFile;
 289         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 290         struct tcon_link *tlink = NULL;
 291         struct cifs_tcon *tcon;
 292         struct TCP_Server_Info *server;
 293
 294         if (file->private_data == NULL) {
 295                 tlink = cifs_sb_tlink(cifs_sb);
 296                 if (IS_ERR(tlink))
 297                         return PTR_ERR(tlink);
 298
 299                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 300                 if (cifsFile == NULL) {
 301                         rc = -ENOMEM;
 302                         goto error_exit;
 303                 }
 304                 file->private_data = cifsFile;
 305                 cifsFile->tlink = cifs_get_tlink(tlink);
 306                 tcon = tlink_tcon(tlink);
 307         } else {
 308                 cifsFile = file->private_data;
 309                 tcon = tlink_tcon(cifsFile->tlink);
 310         }
 311
 312         server = tcon->ses->server;
 313
 314         if (!server->ops->query_dir_first) {
 315                 rc = -ENOSYS;
 316                 goto error_exit;
 317         }
 318
 319         cifsFile->invalidHandle = true;
 320         cifsFile->srch_inf.endOfSearch = false;
 321
 322         full_path = build_path_from_dentry(file->f_path.dentry);
 323         if (full_path == NULL) {
 324                 rc = -ENOMEM;
 325                 goto error_exit;
 326         }
 327
 328         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 329
 330 ffirst_retry:
 331         /* test for Unix extensions */
 332         /* but now check for them on the share/mount not on the SMB session */
 333         /* if (cap_unix(tcon->ses) { */
 334         if (tcon->unix_ext)
 335                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 336         else if ((tcon->ses->capabilities &
 337                   tcon->ses->server->vals->cap_nt_find) == 0) {
 338                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 339         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 340                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 341         } else /* not srvinos - BB fixme add check for backlevel? */ {
 342                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 343         }
 344
 345         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 346         if (backup_cred(cifs_sb))
 347                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 348
 349         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 350                                           &cifsFile->fid, search_flags,
 351                                           &cifsFile->srch_inf);
 352
 353         if (rc == 0)
 354                 cifsFile->invalidHandle = false;
 355         /* BB add following call to handle readdir on new NTFS symlink errors
 356         else if STATUS_STOPPED_ON_SYMLINK
 357                 call get_symlink_reparse_path and retry with new path */
 358         else if ((rc == -EOPNOTSUPP) &&
 359                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 360                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 361                 goto ffirst_retry;
 362         }
 363 error_exit:
 364         kfree(full_path);
 365         cifs_put_tlink(tlink);
 366         return rc;
 367 }
 368
 369 /* return length of unicode string in bytes */
 370 static int cifs_unicode_bytelen(const char *str)
 371 {
 372         int len;
 373         const __le16 *ustr = (const __le16 *)str;
 374
 375         for (len = 0; len <= PATH_MAX; len++) {
 376                 if (ustr[len] == 0)
 377                         return len << 1;
 378         }
 379         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 380         return len << 1;
 381 }
 382
 383 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 384 {
 385         char *new_entry;
 386         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 387
 388         if (level == SMB_FIND_FILE_INFO_STANDARD) {
 389                 FIND_FILE_STANDARD_INFO *pfData;
 390                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 391
 392                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
 393                                 pfData->FileNameLength;
 394         } else
 395                 new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset);
 396         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 397         /* validate that new_entry is not past end of SMB */
 398         if (new_entry >= end_of_smb) {
 399                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 400                          new_entry, end_of_smb, old_entry);
 401                 return NULL;
 402         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 403                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
 404                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 405                    (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
 406                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 407                          new_entry, end_of_smb);
 408                 return NULL;
 409         } else
 410                 return new_entry;
 411
 412 }
 413
 414 struct cifs_dirent {
 415         const char      *name;
 416         size_t          namelen;
 417         u32             resume_key;
 418         u64             ino;
 419 };
 420
 421 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 422                 const FILE_UNIX_INFO *info, bool is_unicode)
 423 {
 424         de->name = &info->FileName[0];
 425         if (is_unicode)
 426                 de->namelen = cifs_unicode_bytelen(de->name);
 427         else
 428                 de->namelen = strnlen(de->name, PATH_MAX);
 429         de->resume_key = info->ResumeKey;
 430         de->ino = le64_to_cpu(info->basic.UniqueId);
 431 }
 432
 433 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 434                 const FILE_DIRECTORY_INFO *info)
 435 {
 436         de->name = &info->FileName[0];
 437         de->namelen = le32_to_cpu(info->FileNameLength);
 438         de->resume_key = info->FileIndex;
 439 }
 440
 441 static void cifs_fill_dirent_full(struct cifs_dirent *de,
 442                 const FILE_FULL_DIRECTORY_INFO *info)
 443 {
 444         de->name = &info->FileName[0];
 445         de->namelen = le32_to_cpu(info->FileNameLength);
 446         de->resume_key = info->FileIndex;
 447 }
 448
 449 static void cifs_fill_dirent_search(struct cifs_dirent *de,
 450                 const SEARCH_ID_FULL_DIR_INFO *info)
 451 {
 452         de->name = &info->FileName[0];
 453         de->namelen = le32_to_cpu(info->FileNameLength);
 454         de->resume_key = info->FileIndex;
 455         de->ino = le64_to_cpu(info->UniqueId);
 456 }
 457
 458 static void cifs_fill_dirent_both(struct cifs_dirent *de,
 459                 const FILE_BOTH_DIRECTORY_INFO *info)
 460 {
 461         de->name = &info->FileName[0];
 462         de->namelen = le32_to_cpu(info->FileNameLength);
 463         de->resume_key = info->FileIndex;
 464 }
 465
 466 static void cifs_fill_dirent_std(struct cifs_dirent *de,
 467                 const FIND_FILE_STANDARD_INFO *info)
 468 {
 469         de->name = &info->FileName[0];
 470         /* one byte length, no endianess conversion */
 471         de->namelen = info->FileNameLength;
 472         de->resume_key = info->ResumeKey;
 473 }
 474
 475 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 476                 u16 level, bool is_unicode)
 477 {
 478         memset(de, 0, sizeof(*de));
 479
 480         switch (level) {
 481         case SMB_FIND_FILE_UNIX:
 482                 cifs_fill_dirent_unix(de, info, is_unicode);
 483                 break;
 484         case SMB_FIND_FILE_DIRECTORY_INFO:
 485                 cifs_fill_dirent_dir(de, info);
 486                 break;
 487         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 488                 cifs_fill_dirent_full(de, info);
 489                 break;
 490         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 491                 cifs_fill_dirent_search(de, info);
 492                 break;
 493         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 494                 cifs_fill_dirent_both(de, info);
 495                 break;
 496         case SMB_FIND_FILE_INFO_STANDARD:
 497                 cifs_fill_dirent_std(de, info);
 498                 break;
 499         default:
 500                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 501                 return -EINVAL;
 502         }
 503
 504         return 0;
 505 }
 506
 507 #define UNICODE_DOT cpu_to_le16(0x2e)
 508
 509 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 510 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 511 {
 512         int rc = 0;
 513
 514         if (!de->name)
 515                 return 0;
 516
 517         if (is_unicode) {
 518                 __le16 *ufilename = (__le16 *)de->name;
 519                 if (de->namelen == 2) {
 520                         /* check for . */
 521                         if (ufilename[0] == UNICODE_DOT)
 522                                 rc = 1;
 523                 } else if (de->namelen == 4) {
 524                         /* check for .. */
 525                         if (ufilename[0] == UNICODE_DOT &&
 526                             ufilename[1] == UNICODE_DOT)
 527                                 rc = 2;
 528                 }
 529         } else /* ASCII */ {
 530                 if (de->namelen == 1) {
 531                         if (de->name[0] == '.')
 532                                 rc = 1;
 533                 } else if (de->namelen == 2) {
 534                         if (de->name[0] == '.' && de->name[1] == '.')
 535                                 rc = 2;
 536                 }
 537         }
 538
 539         return rc;
 540 }
 541
 542 /* Check if directory that we are searching has changed so we can decide
 543    whether we can use the cached search results from the previous search */
 544 static int is_dir_changed(struct file *file)
 545 {
 546         struct inode *inode = file_inode(file);
 547         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 548
 549         if (cifsInfo->time == 0)
 550                 return 1; /* directory was changed, perhaps due to unlink */
 551         else
 552                 return 0;
 553
 554 }
 555
 556 static int cifs_save_resume_key(const char *current_entry,
 557         struct cifsFileInfo *file_info)
 558 {
 559         struct cifs_dirent de;
 560         int rc;
 561
 562         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 563                               file_info->srch_inf.unicode);
 564         if (!rc) {
 565                 file_info->srch_inf.presume_name = de.name;
 566                 file_info->srch_inf.resume_name_len = de.namelen;
 567                 file_info->srch_inf.resume_key = de.resume_key;
 568         }
 569         return rc;
 570 }
 571
 572 /*
 573  * Find the corresponding entry in the search. Note that the SMB server returns
 574  * search entries for . and .. which complicates logic here if we choose to
 575  * parse for them and we do not assume that they are located in the findfirst
 576  * return buffer. We start counting in the buffer with entry 2 and increment for
 577  * every entry (do not increment for . or .. entry).
 578  */
 579 static int
 580 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
 581                 struct file *file, char **current_entry, int *num_to_ret)
 582 {
 583         __u16 search_flags;
 584         int rc = 0;
 585         int pos_in_buf = 0;
 586         loff_t first_entry_in_buffer;
 587         loff_t index_to_find = pos;
 588         struct cifsFileInfo *cfile = file->private_data;
 589         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 590         struct TCP_Server_Info *server = tcon->ses->server;
 591         /* check if index in the buffer */
 592
 593         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 594                 return -ENOSYS;
 595
 596         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 597                 return -ENOENT;
 598
 599         *current_entry = NULL;
 600         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 601                                         cfile->srch_inf.entries_in_buffer;
 602
 603         /*
 604          * If first entry in buf is zero then is first buffer
 605          * in search response data which means it is likely . and ..
 606          * will be in this buffer, although some servers do not return
 607          * . and .. for the root of a drive and for those we need
 608          * to start two entries earlier.
 609          */
 610
 611         dump_cifs_file_struct(file, "In fce ");
 612         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 613              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 614                 /* close and restart search */
 615                 cifs_dbg(FYI, "search backing up - close and restart search\n");
 616                 spin_lock(&cifs_file_list_lock);
 617                 if (!cfile->srch_inf.endOfSearch && !cfile->invalidHandle) {
 618                         cfile->invalidHandle = true;
 619                         spin_unlock(&cifs_file_list_lock);
 620                         if (server->ops->close)
 621                                 server->ops->close(xid, tcon, &cfile->fid);
 622                 } else
 623                         spin_unlock(&cifs_file_list_lock);
 624                 if (cfile->srch_inf.ntwrk_buf_start) {
 625                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 626                         if (cfile->srch_inf.smallBuf)
 627                                 cifs_small_buf_release(cfile->srch_inf.
 628                                                 ntwrk_buf_start);
 629                         else
 630                                 cifs_buf_release(cfile->srch_inf.
 631                                                 ntwrk_buf_start);
 632                         cfile->srch_inf.ntwrk_buf_start = NULL;
 633                 }
 634                 rc = initiate_cifs_search(xid, file);
 635                 if (rc) {
 636                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 637                                  rc);
 638                         return rc;
 639                 }
 640                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 641                 if (cfile->srch_inf.last_entry)
 642                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 643         }
 644
 645         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 646         if (backup_cred(cifs_sb))
 647                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 648
 649         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 650                (rc == 0) && !cfile->srch_inf.endOfSearch) {
 651                 cifs_dbg(FYI, "calling findnext2\n");
 652                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 653                                                  search_flags,
 654                                                  &cfile->srch_inf);
 655                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 656                 if (cfile->srch_inf.last_entry)
 657                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 658                 if (rc)
 659                         return -ENOENT;
 660         }
 661         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 662                 /* we found the buffer that contains the entry */
 663                 /* scan and find it */
 664                 int i;
 665                 char *cur_ent;
 666                 char *end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 667                         server->ops->calc_smb_size(
 668                                         cfile->srch_inf.ntwrk_buf_start);
 669
 670                 cur_ent = cfile->srch_inf.srch_entries_start;
 671                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 672                                         - cfile->srch_inf.entries_in_buffer;
 673                 pos_in_buf = index_to_find - first_entry_in_buffer;
 674                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 675
 676                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 677                         /* go entry by entry figuring out which is first */
 678                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 679                                                 cfile->srch_inf.info_level);
 680                 }
 681                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
 682                         /* BB fixme - check if we should flag this error */
 683                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 684                                  pos_in_buf, index_to_find, rc);
 685                 }
 686                 rc = 0;
 687                 *current_entry = cur_ent;
 688         } else {
 689                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 690                 return 0;
 691         }
 692
 693         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 694                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 695                 *num_to_ret = 0;
 696         } else
 697                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 698
 699         return rc;
 700 }
 701
 702 static int cifs_filldir(char *find_entry, struct file *file,
 703                 struct dir_context *ctx,
 704                 char *scratch_buf, unsigned int max_len)
 705 {
 706         struct cifsFileInfo *file_info = file->private_data;
 707         struct super_block *sb = file->f_path.dentry->d_sb;
 708         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 709         struct cifs_dirent de = { NULL, };
 710         struct cifs_fattr fattr;
 711         struct qstr name;
 712         int rc = 0;
 713         ino_t ino;
 714
 715         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 716                               file_info->srch_inf.unicode);
 717         if (rc)
 718                 return rc;
 719
 720         if (de.namelen > max_len) {
 721                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 722                          de.namelen);
 723                 return -EINVAL;
 724         }
 725
 726         /* skip . and .. since we added them first */
 727         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 728                 return 0;
 729
 730         if (file_info->srch_inf.unicode) {
 731                 struct nls_table *nlt = cifs_sb->local_nls;
 732
 733                 name.name = scratch_buf;
 734                 name.len =
 735                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 736                                         UNICODE_NAME_MAX,
 737                                         min_t(size_t, de.namelen,
 738                                               (size_t)max_len), nlt,
 739                                         cifs_sb->mnt_cifs_flags &
 740                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 741                 name.len -= nls_nullsize(nlt);
 742         } else {
 743                 name.name = de.name;
 744                 name.len = de.namelen;
 745         }
 746
 747         switch (file_info->srch_inf.info_level) {
 748         case SMB_FIND_FILE_UNIX:
 749                 cifs_unix_basic_to_fattr(&fattr,
 750                                          &((FILE_UNIX_INFO *)find_entry)->basic,
 751                                          cifs_sb);
 752                 break;
 753         case SMB_FIND_FILE_INFO_STANDARD:
 754                 cifs_std_info_to_fattr(&fattr,
 755                                        (FIND_FILE_STANDARD_INFO *)find_entry,
 756                                        cifs_sb);
 757                 break;
 758         default:
 759                 cifs_dir_info_to_fattr(&fattr,
 760                                        (FILE_DIRECTORY_INFO *)find_entry,
 761                                        cifs_sb);
 762                 break;
 763         }
 764
 765         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 766                 fattr.cf_uniqueid = de.ino;
 767         } else {
 768                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
 769                 cifs_autodisable_serverino(cifs_sb);
 770         }
 771
 772         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
 773             CIFSCouldBeMFSymlink(&fattr))
 774                 /*
 775                  * trying to get the type and mode can be slow,
 776                  * so just call those regular files for now, and mark
 777                  * for reval
 778                  */
 779                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
 780
 781         cifs_prime_dcache(file->f_dentry, &name, &fattr);
 782
 783         ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
 784         return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
 785 }
 786
 787
 788 int cifs_readdir(struct file *file, struct dir_context *ctx)
 789 {
 790         int rc = 0;
 791         unsigned int xid;
 792         int i;
 793         struct cifs_tcon *tcon;
 794         struct cifsFileInfo *cifsFile = NULL;
 795         char *current_entry;
 796         int num_to_fill = 0;
 797         char *tmp_buf = NULL;
 798         char *end_of_smb;
 799         unsigned int max_len;
 800
 801         xid = get_xid();
 802
 803         /*
 804          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
 805          * '..'. Otherwise we won't be able to notify VFS in case of failure.
 806          */
 807         if (file->private_data == NULL) {
 808                 rc = initiate_cifs_search(xid, file);
 809                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
 810                 if (rc)
 811                         goto rddir2_exit;
 812         }
 813
 814         if (!dir_emit_dots(file, ctx))
 815                 goto rddir2_exit;
 816
 817         /* 1) If search is active,
 818                 is in current search buffer?
 819                 if it before then restart search
 820                 if after then keep searching till find it */
 821
 822         if (file->private_data == NULL) {
 823                 rc = -EINVAL;
 824                 goto rddir2_exit;
 825         }
 826         cifsFile = file->private_data;
 827         if (cifsFile->srch_inf.endOfSearch) {
 828                 if (cifsFile->srch_inf.emptyDir) {
 829                         cifs_dbg(FYI, "End of search, empty dir\n");
 830                         rc = 0;
 831                         goto rddir2_exit;
 832                 }
 833         } /* else {
 834                 cifsFile->invalidHandle = true;
 835                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
 836         } */
 837
 838         tcon = tlink_tcon(cifsFile->tlink);
 839         rc = find_cifs_entry(xid, tcon, ctx->pos, file, &current_entry,
 840                              &num_to_fill);
 841         if (rc) {
 842                 cifs_dbg(FYI, "fce error %d\n", rc);
 843                 goto rddir2_exit;
 844         } else if (current_entry != NULL) {
 845                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
 846         } else {
 847                 cifs_dbg(FYI, "could not find entry\n");
 848                 goto rddir2_exit;
 849         }
 850         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
 851                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
 852         max_len = tcon->ses->server->ops->calc_smb_size(
 853                         cifsFile->srch_inf.ntwrk_buf_start);
 854         end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
 855
 856         tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
 857         if (tmp_buf == NULL) {
 858                 rc = -ENOMEM;
 859                 goto rddir2_exit;
 860         }
 861
 862         for (i = 0; i < num_to_fill; i++) {
 863                 if (current_entry == NULL) {
 864                         /* evaluate whether this case is an error */
 865                         cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
 866                                  num_to_fill, i);
 867                         break;
 868                 }
 869                 /*
 870                  * if buggy server returns . and .. late do we want to
 871                  * check for that here?
 872                  */
 873                 rc = cifs_filldir(current_entry, file, ctx,
 874                                   tmp_buf, max_len);
 875                 if (rc) {
 876                         if (rc > 0)
 877                                 rc = 0;
 878                         break;
 879                 }
 880
 881                 ctx->pos++;
 882                 if (ctx->pos ==
 883                         cifsFile->srch_inf.index_of_last_entry) {
 884                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
 885                                  ctx->pos, tmp_buf);
 886                         cifs_save_resume_key(current_entry, cifsFile);
 887                         break;
 888                 } else
 889                         current_entry =
 890                                 nxt_dir_entry(current_entry, end_of_smb,
 891                                         cifsFile->srch_inf.info_level);
 892         }
 893         kfree(tmp_buf);
 894
 895 rddir2_exit:
 896         free_xid(xid);
 897         return rc;
 898 }