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