fs/ntfs/dir.c

   1 /**
   2  * dir.c - NTFS kernel directory operations. Part of the Linux-NTFS project.
   3  *
   4  * Copyright (c) 2001-2007 Anton Altaparmakov
   5  * Copyright (c) 2002 Richard Russon
   6  *
   7  * This program/include file is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as published
   9  * by the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program/include file is distributed in the hope that it will be
  13  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  14  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program (in the main directory of the Linux-NTFS
  19  * distribution in the file COPYING); if not, write to the Free Software
  20  * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <linux/buffer_head.h>
  24 #include <linux/slab.h>
  25
  26 #include "dir.h"
  27 #include "aops.h"
  28 #include "attrib.h"
  29 #include "mft.h"
  30 #include "debug.h"
  31 #include "ntfs.h"
  32
  33 /**
  34  * The little endian Unicode string $I30 as a global constant.
  35  */
  36 ntfschar I30[5] = { cpu_to_le16('$'), cpu_to_le16('I'),
  37                 cpu_to_le16('3'),       cpu_to_le16('0'), 0 };
  38
  39 /**
  40  * ntfs_lookup_inode_by_name - find an inode in a directory given its name
  41  * @dir_ni:     ntfs inode of the directory in which to search for the name
  42  * @uname:      Unicode name for which to search in the directory
  43  * @uname_len:  length of the name @uname in Unicode characters
  44  * @res:        return the found file name if necessary (see below)
  45  *
  46  * Look for an inode with name @uname in the directory with inode @dir_ni.
  47  * ntfs_lookup_inode_by_name() walks the contents of the directory looking for
  48  * the Unicode name. If the name is found in the directory, the corresponding
  49  * inode number (>= 0) is returned as a mft reference in cpu format, i.e. it
  50  * is a 64-bit number containing the sequence number.
  51  *
  52  * On error, a negative value is returned corresponding to the error code. In
  53  * particular if the inode is not found -ENOENT is returned. Note that you
  54  * can't just check the return value for being negative, you have to check the
  55  * inode number for being negative which you can extract using MREC(return
  56  * value).
  57  *
  58  * Note, @uname_len does not include the (optional) terminating NULL character.
  59  *
  60  * Note, we look for a case sensitive match first but we also look for a case
  61  * insensitive match at the same time. If we find a case insensitive match, we
  62  * save that for the case that we don't find an exact match, where we return
  63  * the case insensitive match and setup @res (which we allocate!) with the mft
  64  * reference, the file name type, length and with a copy of the little endian
  65  * Unicode file name itself. If we match a file name which is in the DOS name
  66  * space, we only return the mft reference and file name type in @res.
  67  * ntfs_lookup() then uses this to find the long file name in the inode itself.
  68  * This is to avoid polluting the dcache with short file names. We want them to
  69  * work but we don't care for how quickly one can access them. This also fixes
  70  * the dcache aliasing issues.
  71  *
  72  * Locking:  - Caller must hold i_mutex on the directory.
  73  *           - Each page cache page in the index allocation mapping must be
  74  *             locked whilst being accessed otherwise we may find a corrupt
  75  *             page due to it being under ->writepage at the moment which
  76  *             applies the mst protection fixups before writing out and then
  77  *             removes them again after the write is complete after which it
  78  *             unlocks the page.
  79  */
  80 MFT_REF ntfs_lookup_inode_by_name(ntfs_inode *dir_ni, const ntfschar *uname,
  81                 const int uname_len, ntfs_name **res)
  82 {
  83         ntfs_volume *vol = dir_ni->vol;
  84         struct super_block *sb = vol->sb;
  85         MFT_RECORD *m;
  86         INDEX_ROOT *ir;
  87         INDEX_ENTRY *ie;
  88         INDEX_ALLOCATION *ia;
  89         u8 *index_end;
  90         u64 mref;
  91         ntfs_attr_search_ctx *ctx;
  92         int err, rc;
  93         VCN vcn, old_vcn;
  94         struct address_space *ia_mapping;
  95         struct page *page;
  96         u8 *kaddr;
  97         ntfs_name *name = NULL;
  98
  99         BUG_ON(!S_ISDIR(VFS_I(dir_ni)->i_mode));
 100         BUG_ON(NInoAttr(dir_ni));
 101         /* Get hold of the mft record for the directory. */
 102         m = map_mft_record(dir_ni);
 103         if (IS_ERR(m)) {
 104                 ntfs_error(sb, "map_mft_record() failed with error code %ld.",
 105                                 -PTR_ERR(m));
 106                 return ERR_MREF(PTR_ERR(m));
 107         }
 108         ctx = ntfs_attr_get_search_ctx(dir_ni, m);
 109         if (unlikely(!ctx)) {
 110                 err = -ENOMEM;
 111                 goto err_out;
 112         }
 113         /* Find the index root attribute in the mft record. */
 114         err = ntfs_attr_lookup(AT_INDEX_ROOT, I30, 4, CASE_SENSITIVE, 0, NULL,
 115                         0, ctx);
 116         if (unlikely(err)) {
 117                 if (err == -ENOENT) {
 118                         ntfs_error(sb, "Index root attribute missing in "
 119                                         "directory inode 0x%lx.",
 120                                         dir_ni->mft_no);
 121                         err = -EIO;
 122                 }
 123                 goto err_out;
 124         }
 125         /* Get to the index root value (it's been verified in read_inode). */
 126         ir = (INDEX_ROOT*)((u8*)ctx->attr +
 127                         le16_to_cpu(ctx->attr->data.resident.value_offset));
 128         index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
 129         /* The first index entry. */
 130         ie = (INDEX_ENTRY*)((u8*)&ir->index +
 131                         le32_to_cpu(ir->index.entries_offset));
 132         /*
 133          * Loop until we exceed valid memory (corruption case) or until we
 134          * reach the last entry.
 135          */
 136         for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
 137                 /* Bounds checks. */
 138                 if ((u8*)ie < (u8*)ctx->mrec || (u8*)ie +
 139                                 sizeof(INDEX_ENTRY_HEADER) > index_end ||
 140                                 (u8*)ie + le16_to_cpu(ie->key_length) >
 141                                 index_end)
 142                         goto dir_err_out;
 143                 /*
 144                  * The last entry cannot contain a name. It can however contain
 145                  * a pointer to a child node in the B+tree so we just break out.
 146                  */
 147                 if (ie->flags & INDEX_ENTRY_END)
 148                         break;
 149                 /*
 150                  * We perform a case sensitive comparison and if that matches
 151                  * we are done and return the mft reference of the inode (i.e.
 152                  * the inode number together with the sequence number for
 153                  * consistency checking). We convert it to cpu format before
 154                  * returning.
 155                  */
 156                 if (ntfs_are_names_equal(uname, uname_len,
 157                                 (ntfschar*)&ie->key.file_name.file_name,
 158                                 ie->key.file_name.file_name_length,
 159                                 CASE_SENSITIVE, vol->upcase, vol->upcase_len)) {
 160 found_it:
 161                         /*
 162                          * We have a perfect match, so we don't need to care
 163                          * about having matched imperfectly before, so we can
 164                          * free name and set *res to NULL.
 165                          * However, if the perfect match is a short file name,
 166                          * we need to signal this through *res, so that
 167                          * ntfs_lookup() can fix dcache aliasing issues.
 168                          * As an optimization we just reuse an existing
 169                          * allocation of *res.
 170                          */
 171                         if (ie->key.file_name.file_name_type == FILE_NAME_DOS) {
 172                                 if (!name) {
 173                                         name = kmalloc(sizeof(ntfs_name),
 174                                                         GFP_NOFS);
 175                                         if (!name) {
 176                                                 err = -ENOMEM;
 177                                                 goto err_out;
 178                                         }
 179                                 }
 180                                 name->mref = le64_to_cpu(
 181                                                 ie->data.dir.indexed_file);
 182                                 name->type = FILE_NAME_DOS;
 183                                 name->len = 0;
 184                                 *res = name;
 185                         } else {
 186                                 kfree(name);
 187                                 *res = NULL;
 188                         }
 189                         mref = le64_to_cpu(ie->data.dir.indexed_file);
 190                         ntfs_attr_put_search_ctx(ctx);
 191                         unmap_mft_record(dir_ni);
 192                         return mref;
 193                 }
 194                 /*
 195                  * For a case insensitive mount, we also perform a case
 196                  * insensitive comparison (provided the file name is not in the
 197                  * POSIX namespace). If the comparison matches, and the name is
 198                  * in the WIN32 namespace, we cache the filename in *res so
 199                  * that the caller, ntfs_lookup(), can work on it. If the
 200                  * comparison matches, and the name is in the DOS namespace, we
 201                  * only cache the mft reference and the file name type (we set
 202                  * the name length to zero for simplicity).
 203                  */
 204                 if (!NVolCaseSensitive(vol) &&
 205                                 ie->key.file_name.file_name_type &&
 206                                 ntfs_are_names_equal(uname, uname_len,
 207                                 (ntfschar*)&ie->key.file_name.file_name,
 208                                 ie->key.file_name.file_name_length,
 209                                 IGNORE_CASE, vol->upcase, vol->upcase_len)) {
 210                         int name_size = sizeof(ntfs_name);
 211                         u8 type = ie->key.file_name.file_name_type;
 212                         u8 len = ie->key.file_name.file_name_length;
 213
 214                         /* Only one case insensitive matching name allowed. */
 215                         if (name) {
 216                                 ntfs_error(sb, "Found already allocated name "
 217                                                 "in phase 1. Please run chkdsk "
 218                                                 "and if that doesn't find any "
 219                                                 "errors please report you saw "
 220                                                 "this message to "
 221                                                 "linux-ntfs-dev@lists."
 222                                                 "sourceforge.net.");
 223                                 goto dir_err_out;
 224                         }
 225
 226                         if (type != FILE_NAME_DOS)
 227                                 name_size += len * sizeof(ntfschar);
 228                         name = kmalloc(name_size, GFP_NOFS);
 229                         if (!name) {
 230                                 err = -ENOMEM;
 231                                 goto err_out;
 232                         }
 233                         name->mref = le64_to_cpu(ie->data.dir.indexed_file);
 234                         name->type = type;
 235                         if (type != FILE_NAME_DOS) {
 236                                 name->len = len;
 237                                 memcpy(name->name, ie->key.file_name.file_name,
 238                                                 len * sizeof(ntfschar));
 239                         } else
 240                                 name->len = 0;
 241                         *res = name;
 242                 }
 243                 /*
 244                  * Not a perfect match, need to do full blown collation so we
 245                  * know which way in the B+tree we have to go.
 246                  */
 247                 rc = ntfs_collate_names(uname, uname_len,
 248                                 (ntfschar*)&ie->key.file_name.file_name,
 249                                 ie->key.file_name.file_name_length, 1,
 250                                 IGNORE_CASE, vol->upcase, vol->upcase_len);
 251                 /*
 252                  * If uname collates before the name of the current entry, there
 253                  * is definitely no such name in this index but we might need to
 254                  * descend into the B+tree so we just break out of the loop.
 255                  */
 256                 if (rc == -1)
 257                         break;
 258                 /* The names are not equal, continue the search. */
 259                 if (rc)
 260                         continue;
 261                 /*
 262                  * Names match with case insensitive comparison, now try the
 263                  * case sensitive comparison, which is required for proper
 264                  * collation.
 265                  */
 266                 rc = ntfs_collate_names(uname, uname_len,
 267                                 (ntfschar*)&ie->key.file_name.file_name,
 268                                 ie->key.file_name.file_name_length, 1,
 269                                 CASE_SENSITIVE, vol->upcase, vol->upcase_len);
 270                 if (rc == -1)
 271                         break;
 272                 if (rc)
 273                         continue;
 274                 /*
 275                  * Perfect match, this will never happen as the
 276                  * ntfs_are_names_equal() call will have gotten a match but we
 277                  * still treat it correctly.
 278                  */
 279                 goto found_it;
 280         }
 281         /*
 282          * We have finished with this index without success. Check for the
 283          * presence of a child node and if not present return -ENOENT, unless
 284          * we have got a matching name cached in name in which case return the
 285          * mft reference associated with it.
 286          */
 287         if (!(ie->flags & INDEX_ENTRY_NODE)) {
 288                 if (name) {
 289                         ntfs_attr_put_search_ctx(ctx);
 290                         unmap_mft_record(dir_ni);
 291                         return name->mref;
 292                 }
 293                 ntfs_debug("Entry not found.");
 294                 err = -ENOENT;
 295                 goto err_out;
 296         } /* Child node present, descend into it. */
 297         /* Consistency check: Verify that an index allocation exists. */
 298         if (!NInoIndexAllocPresent(dir_ni)) {
 299                 ntfs_error(sb, "No index allocation attribute but index entry "
 300                                 "requires one. Directory inode 0x%lx is "
 301                                 "corrupt or driver bug.", dir_ni->mft_no);
 302                 goto err_out;
 303         }
 304         /* Get the starting vcn of the index_block holding the child node. */
 305         vcn = sle64_to_cpup((sle64*)((u8*)ie + le16_to_cpu(ie->length) - 8));
 306         ia_mapping = VFS_I(dir_ni)->i_mapping;
 307         /*
 308          * We are done with the index root and the mft record. Release them,
 309          * otherwise we deadlock with ntfs_map_page().
 310          */
 311         ntfs_attr_put_search_ctx(ctx);
 312         unmap_mft_record(dir_ni);
 313         m = NULL;
 314         ctx = NULL;
 315 descend_into_child_node:
 316         /*
 317          * Convert vcn to index into the index allocation attribute in units
 318          * of PAGE_CACHE_SIZE and map the page cache page, reading it from
 319          * disk if necessary.
 320          */
 321         page = ntfs_map_page(ia_mapping, vcn <<
 322                         dir_ni->itype.index.vcn_size_bits >> PAGE_CACHE_SHIFT);
 323         if (IS_ERR(page)) {
 324                 ntfs_error(sb, "Failed to map directory index page, error %ld.",
 325                                 -PTR_ERR(page));
 326                 err = PTR_ERR(page);
 327                 goto err_out;
 328         }
 329         lock_page(page);
 330         kaddr = (u8*)page_address(page);
 331 fast_descend_into_child_node:
 332         /* Get to the index allocation block. */
 333         ia = (INDEX_ALLOCATION*)(kaddr + ((vcn <<
 334                         dir_ni->itype.index.vcn_size_bits) & ~PAGE_CACHE_MASK));
 335         /* Bounds checks. */
 336         if ((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_CACHE_SIZE) {
 337                 ntfs_error(sb, "Out of bounds check failed. Corrupt directory "
 338                                 "inode 0x%lx or driver bug.", dir_ni->mft_no);
 339                 goto unm_err_out;
 340         }
 341         /* Catch multi sector transfer fixup errors. */
 342         if (unlikely(!ntfs_is_indx_record(ia->magic))) {
 343                 ntfs_error(sb, "Directory index record with vcn 0x%llx is "
 344                                 "corrupt.  Corrupt inode 0x%lx.  Run chkdsk.",
 345                                 (unsigned long long)vcn, dir_ni->mft_no);
 346                 goto unm_err_out;
 347         }
 348         if (sle64_to_cpu(ia->index_block_vcn) != vcn) {
 349                 ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is "
 350                                 "different from expected VCN (0x%llx). "
 351                                 "Directory inode 0x%lx is corrupt or driver "
 352                                 "bug.", (unsigned long long)
 353                                 sle64_to_cpu(ia->index_block_vcn),
 354                                 (unsigned long long)vcn, dir_ni->mft_no);
 355                 goto unm_err_out;
 356         }
 357         if (le32_to_cpu(ia->index.allocated_size) + 0x18 !=
 358                         dir_ni->itype.index.block_size) {
 359                 ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
 360                                 "0x%lx has a size (%u) differing from the "
 361                                 "directory specified size (%u). Directory "
 362                                 "inode is corrupt or driver bug.",
 363                                 (unsigned long long)vcn, dir_ni->mft_no,
 364                                 le32_to_cpu(ia->index.allocated_size) + 0x18,
 365                                 dir_ni->itype.index.block_size);
 366                 goto unm_err_out;
 367         }
 368         index_end = (u8*)ia + dir_ni->itype.index.block_size;
 369         if (index_end > kaddr + PAGE_CACHE_SIZE) {
 370                 ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
 371                                 "0x%lx crosses page boundary. Impossible! "
 372                                 "Cannot access! This is probably a bug in the "
 373                                 "driver.", (unsigned long long)vcn,
 374                                 dir_ni->mft_no);
 375                 goto unm_err_out;
 376         }
 377         index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
 378         if (index_end > (u8*)ia + dir_ni->itype.index.block_size) {
 379                 ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of directory "
 380                                 "inode 0x%lx exceeds maximum size.",
 381                                 (unsigned long long)vcn, dir_ni->mft_no);
 382                 goto unm_err_out;
 383         }
 384         /* The first index entry. */
 385         ie = (INDEX_ENTRY*)((u8*)&ia->index +
 386                         le32_to_cpu(ia->index.entries_offset));
 387         /*
 388          * Iterate similar to above big loop but applied to index buffer, thus
 389          * loop until we exceed valid memory (corruption case) or until we
 390          * reach the last entry.
 391          */
 392         for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
 393                 /* Bounds check. */
 394                 if ((u8*)ie < (u8*)ia || (u8*)ie +
 395                                 sizeof(INDEX_ENTRY_HEADER) > index_end ||
 396                                 (u8*)ie + le16_to_cpu(ie->key_length) >
 397                                 index_end) {
 398                         ntfs_error(sb, "Index entry out of bounds in "
 399                                         "directory inode 0x%lx.",
 400                                         dir_ni->mft_no);
 401                         goto unm_err_out;
 402                 }
 403                 /*
 404                  * The last entry cannot contain a name. It can however contain
 405                  * a pointer to a child node in the B+tree so we just break out.
 406                  */
 407                 if (ie->flags & INDEX_ENTRY_END)
 408                         break;
 409                 /*
 410                  * We perform a case sensitive comparison and if that matches
 411                  * we are done and return the mft reference of the inode (i.e.
 412                  * the inode number together with the sequence number for
 413                  * consistency checking). We convert it to cpu format before
 414                  * returning.
 415                  */
 416                 if (ntfs_are_names_equal(uname, uname_len,
 417                                 (ntfschar*)&ie->key.file_name.file_name,
 418                                 ie->key.file_name.file_name_length,
 419                                 CASE_SENSITIVE, vol->upcase, vol->upcase_len)) {
 420 found_it2:
 421                         /*
 422                          * We have a perfect match, so we don't need to care
 423                          * about having matched imperfectly before, so we can
 424                          * free name and set *res to NULL.
 425                          * However, if the perfect match is a short file name,
 426                          * we need to signal this through *res, so that
 427                          * ntfs_lookup() can fix dcache aliasing issues.
 428                          * As an optimization we just reuse an existing
 429                          * allocation of *res.
 430                          */
 431                         if (ie->key.file_name.file_name_type == FILE_NAME_DOS) {
 432                                 if (!name) {
 433                                         name = kmalloc(sizeof(ntfs_name),
 434                                                         GFP_NOFS);
 435                                         if (!name) {
 436                                                 err = -ENOMEM;
 437                                                 goto unm_err_out;
 438                                         }
 439                                 }
 440                                 name->mref = le64_to_cpu(
 441                                                 ie->data.dir.indexed_file);
 442                                 name->type = FILE_NAME_DOS;
 443                                 name->len = 0;
 444                                 *res = name;
 445                         } else {
 446                                 kfree(name);
 447                                 *res = NULL;
 448                         }
 449                         mref = le64_to_cpu(ie->data.dir.indexed_file);
 450                         unlock_page(page);
 451                         ntfs_unmap_page(page);
 452                         return mref;
 453                 }
 454                 /*
 455                  * For a case insensitive mount, we also perform a case
 456                  * insensitive comparison (provided the file name is not in the
 457                  * POSIX namespace). If the comparison matches, and the name is
 458                  * in the WIN32 namespace, we cache the filename in *res so
 459                  * that the caller, ntfs_lookup(), can work on it. If the
 460                  * comparison matches, and the name is in the DOS namespace, we
 461                  * only cache the mft reference and the file name type (we set
 462                  * the name length to zero for simplicity).
 463                  */
 464                 if (!NVolCaseSensitive(vol) &&
 465                                 ie->key.file_name.file_name_type &&
 466                                 ntfs_are_names_equal(uname, uname_len,
 467                                 (ntfschar*)&ie->key.file_name.file_name,
 468                                 ie->key.file_name.file_name_length,
 469                                 IGNORE_CASE, vol->upcase, vol->upcase_len)) {
 470                         int name_size = sizeof(ntfs_name);
 471                         u8 type = ie->key.file_name.file_name_type;
 472                         u8 len = ie->key.file_name.file_name_length;
 473
 474                         /* Only one case insensitive matching name allowed. */
 475                         if (name) {
 476                                 ntfs_error(sb, "Found already allocated name "
 477                                                 "in phase 2. Please run chkdsk "
 478                                                 "and if that doesn't find any "
 479                                                 "errors please report you saw "
 480                                                 "this message to "
 481                                                 "linux-ntfs-dev@lists."
 482                                                 "sourceforge.net.");
 483                                 unlock_page(page);
 484                                 ntfs_unmap_page(page);
 485                                 goto dir_err_out;
 486                         }
 487
 488                         if (type != FILE_NAME_DOS)
 489                                 name_size += len * sizeof(ntfschar);
 490                         name = kmalloc(name_size, GFP_NOFS);
 491                         if (!name) {
 492                                 err = -ENOMEM;
 493                                 goto unm_err_out;
 494                         }
 495                         name->mref = le64_to_cpu(ie->data.dir.indexed_file);
 496                         name->type = type;
 497                         if (type != FILE_NAME_DOS) {
 498                                 name->len = len;
 499                                 memcpy(name->name, ie->key.file_name.file_name,
 500                                                 len * sizeof(ntfschar));
 501                         } else
 502                                 name->len = 0;
 503                         *res = name;
 504                 }
 505                 /*
 506                  * Not a perfect match, need to do full blown collation so we
 507                  * know which way in the B+tree we have to go.
 508                  */
 509                 rc = ntfs_collate_names(uname, uname_len,
 510                                 (ntfschar*)&ie->key.file_name.file_name,
 511                                 ie->key.file_name.file_name_length, 1,
 512                                 IGNORE_CASE, vol->upcase, vol->upcase_len);
 513                 /*
 514                  * If uname collates before the name of the current entry, there
 515                  * is definitely no such name in this index but we might need to
 516                  * descend into the B+tree so we just break out of the loop.
 517                  */
 518                 if (rc == -1)
 519                         break;
 520                 /* The names are not equal, continue the search. */
 521                 if (rc)
 522                         continue;
 523                 /*
 524                  * Names match with case insensitive comparison, now try the
 525                  * case sensitive comparison, which is required for proper
 526                  * collation.
 527                  */
 528                 rc = ntfs_collate_names(uname, uname_len,
 529                                 (ntfschar*)&ie->key.file_name.file_name,
 530                                 ie->key.file_name.file_name_length, 1,
 531                                 CASE_SENSITIVE, vol->upcase, vol->upcase_len);
 532                 if (rc == -1)
 533                         break;
 534                 if (rc)
 535                         continue;
 536                 /*
 537                  * Perfect match, this will never happen as the
 538                  * ntfs_are_names_equal() call will have gotten a match but we
 539                  * still treat it correctly.
 540                  */
 541                 goto found_it2;
 542         }
 543         /*
 544          * We have finished with this index buffer without success. Check for
 545          * the presence of a child node.
 546          */
 547         if (ie->flags & INDEX_ENTRY_NODE) {
 548                 if ((ia->index.flags & NODE_MASK) == LEAF_NODE) {
 549                         ntfs_error(sb, "Index entry with child node found in "
 550                                         "a leaf node in directory inode 0x%lx.",
 551                                         dir_ni->mft_no);
 552                         goto unm_err_out;
 553                 }
 554                 /* Child node present, descend into it. */
 555                 old_vcn = vcn;
 556                 vcn = sle64_to_cpup((sle64*)((u8*)ie +
 557                                 le16_to_cpu(ie->length) - 8));
 558                 if (vcn >= 0) {
 559                         /* If vcn is in the same page cache page as old_vcn we
 560                          * recycle the mapped page. */
 561                         if (old_vcn << vol->cluster_size_bits >>
 562                                         PAGE_CACHE_SHIFT == vcn <<
 563                                         vol->cluster_size_bits >>
 564                                         PAGE_CACHE_SHIFT)
 565                                 goto fast_descend_into_child_node;
 566                         unlock_page(page);
 567                         ntfs_unmap_page(page);
 568                         goto descend_into_child_node;
 569                 }
 570                 ntfs_error(sb, "Negative child node vcn in directory inode "
 571                                 "0x%lx.", dir_ni->mft_no);
 572                 goto unm_err_out;
 573         }
 574         /*
 575          * No child node present, return -ENOENT, unless we have got a matching
 576          * name cached in name in which case return the mft reference
 577          * associated with it.
 578          */
 579         if (name) {
 580                 unlock_page(page);
 581                 ntfs_unmap_page(page);
 582                 return name->mref;
 583         }
 584         ntfs_debug("Entry not found.");
 585         err = -ENOENT;
 586 unm_err_out:
 587         unlock_page(page);
 588         ntfs_unmap_page(page);
 589 err_out:
 590         if (!err)
 591                 err = -EIO;
 592         if (ctx)
 593                 ntfs_attr_put_search_ctx(ctx);
 594         if (m)
 595                 unmap_mft_record(dir_ni);
 596         if (name) {
 597                 kfree(name);
 598                 *res = NULL;
 599         }
 600         return ERR_MREF(err);
 601 dir_err_out:
 602         ntfs_error(sb, "Corrupt directory.  Aborting lookup.");
 603         goto err_out;
 604 }
 605
 606 #if 0
 607
 608 // TODO: (AIA)
 609 // The algorithm embedded in this code will be required for the time when we
 610 // want to support adding of entries to directories, where we require correct
 611 // collation of file names in order not to cause corruption of the filesystem.
 612
 613 /**
 614  * ntfs_lookup_inode_by_name - find an inode in a directory given its name
 615  * @dir_ni:     ntfs inode of the directory in which to search for the name
 616  * @uname:      Unicode name for which to search in the directory
 617  * @uname_len:  length of the name @uname in Unicode characters
 618  *
 619  * Look for an inode with name @uname in the directory with inode @dir_ni.
 620  * ntfs_lookup_inode_by_name() walks the contents of the directory looking for
 621  * the Unicode name. If the name is found in the directory, the corresponding
 622  * inode number (>= 0) is returned as a mft reference in cpu format, i.e. it
 623  * is a 64-bit number containing the sequence number.
 624  *
 625  * On error, a negative value is returned corresponding to the error code. In
 626  * particular if the inode is not found -ENOENT is returned. Note that you
 627  * can't just check the return value for being negative, you have to check the
 628  * inode number for being negative which you can extract using MREC(return
 629  * value).
 630  *
 631  * Note, @uname_len does not include the (optional) terminating NULL character.
 632  */
 633 u64 ntfs_lookup_inode_by_name(ntfs_inode *dir_ni, const ntfschar *uname,
 634                 const int uname_len)
 635 {
 636         ntfs_volume *vol = dir_ni->vol;
 637         struct super_block *sb = vol->sb;
 638         MFT_RECORD *m;
 639         INDEX_ROOT *ir;
 640         INDEX_ENTRY *ie;
 641         INDEX_ALLOCATION *ia;
 642         u8 *index_end;
 643         u64 mref;
 644         ntfs_attr_search_ctx *ctx;
 645         int err, rc;
 646         IGNORE_CASE_BOOL ic;
 647         VCN vcn, old_vcn;
 648         struct address_space *ia_mapping;
 649         struct page *page;
 650         u8 *kaddr;
 651
 652         /* Get hold of the mft record for the directory. */
 653         m = map_mft_record(dir_ni);
 654         if (IS_ERR(m)) {
 655                 ntfs_error(sb, "map_mft_record() failed with error code %ld.",
 656                                 -PTR_ERR(m));
 657                 return ERR_MREF(PTR_ERR(m));
 658         }
 659         ctx = ntfs_attr_get_search_ctx(dir_ni, m);
 660         if (!ctx) {
 661                 err = -ENOMEM;
 662                 goto err_out;
 663         }
 664         /* Find the index root attribute in the mft record. */
 665         err = ntfs_attr_lookup(AT_INDEX_ROOT, I30, 4, CASE_SENSITIVE, 0, NULL,
 666                         0, ctx);
 667         if (unlikely(err)) {
 668                 if (err == -ENOENT) {
 669                         ntfs_error(sb, "Index root attribute missing in "
 670                                         "directory inode 0x%lx.",
 671                                         dir_ni->mft_no);
 672                         err = -EIO;
 673                 }
 674                 goto err_out;
 675         }
 676         /* Get to the index root value (it's been verified in read_inode). */
 677         ir = (INDEX_ROOT*)((u8*)ctx->attr +
 678                         le16_to_cpu(ctx->attr->data.resident.value_offset));
 679         index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
 680         /* The first index entry. */
 681         ie = (INDEX_ENTRY*)((u8*)&ir->index +
 682                         le32_to_cpu(ir->index.entries_offset));
 683         /*
 684          * Loop until we exceed valid memory (corruption case) or until we
 685          * reach the last entry.
 686          */
 687         for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
 688                 /* Bounds checks. */
 689                 if ((u8*)ie < (u8*)ctx->mrec || (u8*)ie +
 690                                 sizeof(INDEX_ENTRY_HEADER) > index_end ||
 691                                 (u8*)ie + le16_to_cpu(ie->key_length) >
 692                                 index_end)
 693                         goto dir_err_out;
 694                 /*
 695                  * The last entry cannot contain a name. It can however contain
 696                  * a pointer to a child node in the B+tree so we just break out.
 697                  */
 698                 if (ie->flags & INDEX_ENTRY_END)
 699                         break;
 700                 /*
 701                  * If the current entry has a name type of POSIX, the name is
 702                  * case sensitive and not otherwise. This has the effect of us
 703                  * not being able to access any POSIX file names which collate
 704                  * after the non-POSIX one when they only differ in case, but
 705                  * anyone doing screwy stuff like that deserves to burn in
 706                  * hell... Doing that kind of stuff on NT4 actually causes
 707                  * corruption on the partition even when using SP6a and Linux
 708                  * is not involved at all.
 709                  */
 710                 ic = ie->key.file_name.file_name_type ? IGNORE_CASE :
 711                                 CASE_SENSITIVE;
 712                 /*
 713                  * If the names match perfectly, we are done and return the
 714                  * mft reference of the inode (i.e. the inode number together
 715                  * with the sequence number for consistency checking. We
 716                  * convert it to cpu format before returning.
 717                  */
 718                 if (ntfs_are_names_equal(uname, uname_len,
 719                                 (ntfschar*)&ie->key.file_name.file_name,
 720                                 ie->key.file_name.file_name_length, ic,
 721                                 vol->upcase, vol->upcase_len)) {
 722 found_it:
 723                         mref = le64_to_cpu(ie->data.dir.indexed_file);
 724                         ntfs_attr_put_search_ctx(ctx);
 725                         unmap_mft_record(dir_ni);
 726                         return mref;
 727                 }
 728                 /*
 729                  * Not a perfect match, need to do full blown collation so we
 730                  * know which way in the B+tree we have to go.
 731                  */
 732                 rc = ntfs_collate_names(uname, uname_len,
 733                                 (ntfschar*)&ie->key.file_name.file_name,
 734                                 ie->key.file_name.file_name_length, 1,
 735                                 IGNORE_CASE, vol->upcase, vol->upcase_len);
 736                 /*
 737                  * If uname collates before the name of the current entry, there
 738                  * is definitely no such name in this index but we might need to
 739                  * descend into the B+tree so we just break out of the loop.
 740                  */
 741                 if (rc == -1)
 742                         break;
 743                 /* The names are not equal, continue the search. */
 744                 if (rc)
 745                         continue;
 746                 /*
 747                  * Names match with case insensitive comparison, now try the
 748                  * case sensitive comparison, which is required for proper
 749                  * collation.
 750                  */
 751                 rc = ntfs_collate_names(uname, uname_len,
 752                                 (ntfschar*)&ie->key.file_name.file_name,
 753                                 ie->key.file_name.file_name_length, 1,
 754                                 CASE_SENSITIVE, vol->upcase, vol->upcase_len);
 755                 if (rc == -1)
 756                         break;
 757                 if (rc)
 758                         continue;
 759                 /*
 760                  * Perfect match, this will never happen as the
 761                  * ntfs_are_names_equal() call will have gotten a match but we
 762                  * still treat it correctly.
 763                  */
 764                 goto found_it;
 765         }
 766         /*
 767          * We have finished with this index without success. Check for the
 768          * presence of a child node.
 769          */
 770         if (!(ie->flags & INDEX_ENTRY_NODE)) {
 771                 /* No child node, return -ENOENT. */
 772                 err = -ENOENT;
 773                 goto err_out;
 774         } /* Child node present, descend into it. */
 775         /* Consistency check: Verify that an index allocation exists. */
 776         if (!NInoIndexAllocPresent(dir_ni)) {
 777                 ntfs_error(sb, "No index allocation attribute but index entry "
 778                                 "requires one. Directory inode 0x%lx is "
 779                                 "corrupt or driver bug.", dir_ni->mft_no);
 780                 goto err_out;
 781         }
 782         /* Get the starting vcn of the index_block holding the child node. */
 783         vcn = sle64_to_cpup((u8*)ie + le16_to_cpu(ie->length) - 8);
 784         ia_mapping = VFS_I(dir_ni)->i_mapping;
 785         /*
 786          * We are done with the index root and the mft record. Release them,
 787          * otherwise we deadlock with ntfs_map_page().
 788          */
 789         ntfs_attr_put_search_ctx(ctx);
 790         unmap_mft_record(dir_ni);
 791         m = NULL;
 792         ctx = NULL;
 793 descend_into_child_node:
 794         /*
 795          * Convert vcn to index into the index allocation attribute in units
 796          * of PAGE_CACHE_SIZE and map the page cache page, reading it from
 797          * disk if necessary.
 798          */
 799         page = ntfs_map_page(ia_mapping, vcn <<
 800                         dir_ni->itype.index.vcn_size_bits >> PAGE_CACHE_SHIFT);
 801         if (IS_ERR(page)) {
 802                 ntfs_error(sb, "Failed to map directory index page, error %ld.",
 803                                 -PTR_ERR(page));
 804                 err = PTR_ERR(page);
 805                 goto err_out;
 806         }
 807         lock_page(page);
 808         kaddr = (u8*)page_address(page);
 809 fast_descend_into_child_node:
 810         /* Get to the index allocation block. */
 811         ia = (INDEX_ALLOCATION*)(kaddr + ((vcn <<
 812                         dir_ni->itype.index.vcn_size_bits) & ~PAGE_CACHE_MASK));
 813         /* Bounds checks. */
 814         if ((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_CACHE_SIZE) {
 815                 ntfs_error(sb, "Out of bounds check failed. Corrupt directory "
 816                                 "inode 0x%lx or driver bug.", dir_ni->mft_no);
 817                 goto unm_err_out;
 818         }
 819         /* Catch multi sector transfer fixup errors. */
 820         if (unlikely(!ntfs_is_indx_record(ia->magic))) {
 821                 ntfs_error(sb, "Directory index record with vcn 0x%llx is "
 822                                 "corrupt.  Corrupt inode 0x%lx.  Run chkdsk.",
 823                                 (unsigned long long)vcn, dir_ni->mft_no);
 824                 goto unm_err_out;
 825         }
 826         if (sle64_to_cpu(ia->index_block_vcn) != vcn) {
 827                 ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is "
 828                                 "different from expected VCN (0x%llx). "
 829                                 "Directory inode 0x%lx is corrupt or driver "
 830                                 "bug.", (unsigned long long)
 831                                 sle64_to_cpu(ia->index_block_vcn),
 832                                 (unsigned long long)vcn, dir_ni->mft_no);
 833                 goto unm_err_out;
 834         }
 835         if (le32_to_cpu(ia->index.allocated_size) + 0x18 !=
 836                         dir_ni->itype.index.block_size) {
 837                 ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
 838                                 "0x%lx has a size (%u) differing from the "
 839                                 "directory specified size (%u). Directory "
 840                                 "inode is corrupt or driver bug.",
 841                                 (unsigned long long)vcn, dir_ni->mft_no,
 842                                 le32_to_cpu(ia->index.allocated_size) + 0x18,
 843                                 dir_ni->itype.index.block_size);
 844                 goto unm_err_out;
 845         }
 846         index_end = (u8*)ia + dir_ni->itype.index.block_size;
 847         if (index_end > kaddr + PAGE_CACHE_SIZE) {
 848                 ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
 849                                 "0x%lx crosses page boundary. Impossible! "
 850                                 "Cannot access! This is probably a bug in the "
 851                                 "driver.", (unsigned long long)vcn,
 852                                 dir_ni->mft_no);
 853                 goto unm_err_out;
 854         }
 855         index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
 856         if (index_end > (u8*)ia + dir_ni->itype.index.block_size) {
 857                 ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of directory "
 858                                 "inode 0x%lx exceeds maximum size.",
 859                                 (unsigned long long)vcn, dir_ni->mft_no);
 860                 goto unm_err_out;
 861         }
 862         /* The first index entry. */
 863         ie = (INDEX_ENTRY*)((u8*)&ia->index +
 864                         le32_to_cpu(ia->index.entries_offset));
 865         /*
 866          * Iterate similar to above big loop but applied to index buffer, thus
 867          * loop until we exceed valid memory (corruption case) or until we
 868          * reach the last entry.
 869          */
 870         for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
 871                 /* Bounds check. */
 872                 if ((u8*)ie < (u8*)ia || (u8*)ie +
 873                                 sizeof(INDEX_ENTRY_HEADER) > index_end ||
 874                                 (u8*)ie + le16_to_cpu(ie->key_length) >
 875                                 index_end) {
 876                         ntfs_error(sb, "Index entry out of bounds in "
 877                                         "directory inode 0x%lx.",
 878                                         dir_ni->mft_no);
 879                         goto unm_err_out;
 880                 }
 881                 /*
 882                  * The last entry cannot contain a name. It can however contain
 883                  * a pointer to a child node in the B+tree so we just break out.
 884                  */
 885                 if (ie->flags & INDEX_ENTRY_END)
 886                         break;
 887                 /*
 888                  * If the current entry has a name type of POSIX, the name is
 889                  * case sensitive and not otherwise. This has the effect of us
 890                  * not being able to access any POSIX file names which collate
 891                  * after the non-POSIX one when they only differ in case, but
 892                  * anyone doing screwy stuff like that deserves to burn in
 893                  * hell... Doing that kind of stuff on NT4 actually causes
 894                  * corruption on the partition even when using SP6a and Linux
 895                  * is not involved at all.
 896                  */
 897                 ic = ie->key.file_name.file_name_type ? IGNORE_CASE :
 898                                 CASE_SENSITIVE;
 899                 /*
 900                  * If the names match perfectly, we are done and return the
 901                  * mft reference of the inode (i.e. the inode number together
 902                  * with the sequence number for consistency checking. We
 903                  * convert it to cpu format before returning.
 904                  */
 905                 if (ntfs_are_names_equal(uname, uname_len,
 906                                 (ntfschar*)&ie->key.file_name.file_name,
 907                                 ie->key.file_name.file_name_length, ic,
 908                                 vol->upcase, vol->upcase_len)) {
 909 found_it2:
 910                         mref = le64_to_cpu(ie->data.dir.indexed_file);
 911                         unlock_page(page);
 912                         ntfs_unmap_page(page);
 913                         return mref;
 914                 }
 915                 /*
 916                  * Not a perfect match, need to do full blown collation so we
 917                  * know which way in the B+tree we have to go.
 918                  */
 919                 rc = ntfs_collate_names(uname, uname_len,
 920                                 (ntfschar*)&ie->key.file_name.file_name,
 921                                 ie->key.file_name.file_name_length, 1,
 922                                 IGNORE_CASE, vol->upcase, vol->upcase_len);
 923                 /*
 924                  * If uname collates before the name of the current entry, there
 925                  * is definitely no such name in this index but we might need to
 926                  * descend into the B+tree so we just break out of the loop.
 927                  */
 928                 if (rc == -1)
 929                         break;
 930                 /* The names are not equal, continue the search. */
 931                 if (rc)
 932                         continue;
 933                 /*
 934                  * Names match with case insensitive comparison, now try the
 935                  * case sensitive comparison, which is required for proper
 936                  * collation.
 937                  */
 938                 rc = ntfs_collate_names(uname, uname_len,
 939                                 (ntfschar*)&ie->key.file_name.file_name,
 940                                 ie->key.file_name.file_name_length, 1,
 941                                 CASE_SENSITIVE, vol->upcase, vol->upcase_len);
 942                 if (rc == -1)
 943                         break;
 944                 if (rc)
 945                         continue;
 946                 /*
 947                  * Perfect match, this will never happen as the
 948                  * ntfs_are_names_equal() call will have gotten a match but we
 949                  * still treat it correctly.
 950                  */
 951                 goto found_it2;
 952         }
 953         /*
 954          * We have finished with this index buffer without success. Check for
 955          * the presence of a child node.
 956          */
 957         if (ie->flags & INDEX_ENTRY_NODE) {
 958                 if ((ia->index.flags & NODE_MASK) == LEAF_NODE) {
 959                         ntfs_error(sb, "Index entry with child node found in "
 960                                         "a leaf node in directory inode 0x%lx.",
 961                                         dir_ni->mft_no);
 962                         goto unm_err_out;
 963                 }
 964                 /* Child node present, descend into it. */
 965                 old_vcn = vcn;
 966                 vcn = sle64_to_cpup((u8*)ie + le16_to_cpu(ie->length) - 8);
 967                 if (vcn >= 0) {
 968                         /* If vcn is in the same page cache page as old_vcn we
 969                          * recycle the mapped page. */
 970                         if (old_vcn << vol->cluster_size_bits >>
 971                                         PAGE_CACHE_SHIFT == vcn <<
 972                                         vol->cluster_size_bits >>
 973                                         PAGE_CACHE_SHIFT)
 974                                 goto fast_descend_into_child_node;
 975                         unlock_page(page);
 976                         ntfs_unmap_page(page);
 977                         goto descend_into_child_node;
 978                 }
 979                 ntfs_error(sb, "Negative child node vcn in directory inode "
 980                                 "0x%lx.", dir_ni->mft_no);
 981                 goto unm_err_out;
 982         }
 983         /* No child node, return -ENOENT. */
 984         ntfs_debug("Entry not found.");
 985         err = -ENOENT;
 986 unm_err_out:
 987         unlock_page(page);
 988         ntfs_unmap_page(page);
 989 err_out:
 990         if (!err)
 991                 err = -EIO;
 992         if (ctx)
 993                 ntfs_attr_put_search_ctx(ctx);
 994         if (m)
 995                 unmap_mft_record(dir_ni);
 996         return ERR_MREF(err);
 997 dir_err_out:
 998         ntfs_error(sb, "Corrupt directory. Aborting lookup.");
 999         goto err_out;
1000 }
1001
1002 #endif
1003
1004 /**
1005  * ntfs_filldir - ntfs specific filldir method
1006  * @vol:        current ntfs volume
1007  * @fpos:       position in the directory
1008  * @ndir:       ntfs inode of current directory
1009  * @ia_page:    page in which the index allocation buffer @ie is in resides
1010  * @ie:         current index entry
1011  * @name:       buffer to use for the converted name
1012  * @dirent:     vfs filldir callback context
1013  * @filldir:    vfs filldir callback
1014  *
1015  * Convert the Unicode @name to the loaded NLS and pass it to the @filldir
1016  * callback.
1017  *
1018  * If @ia_page is not NULL it is the locked page containing the index
1019  * allocation block containing the index entry @ie.
1020  *
1021  * Note, we drop (and then reacquire) the page lock on @ia_page across the
1022  * @filldir() call otherwise we would deadlock with NFSd when it calls ->lookup
1023  * since ntfs_lookup() will lock the same page.  As an optimization, we do not
1024  * retake the lock if we are returning a non-zero value as ntfs_readdir()
1025  * would need to drop the lock immediately anyway.
1026  */
1027 static inline int ntfs_filldir(ntfs_volume *vol, loff_t fpos,
1028                 ntfs_inode *ndir, struct page *ia_page, INDEX_ENTRY *ie,
1029                 u8 *name, void *dirent, filldir_t filldir)
1030 {
1031         unsigned long mref;
1032         int name_len, rc;
1033         unsigned dt_type;
1034         FILE_NAME_TYPE_FLAGS name_type;
1035
1036         name_type = ie->key.file_name.file_name_type;
1037         if (name_type == FILE_NAME_DOS) {
1038                 ntfs_debug("Skipping DOS name space entry.");
1039                 return 0;
1040         }
1041         if (MREF_LE(ie->data.dir.indexed_file) == FILE_root) {
1042                 ntfs_debug("Skipping root directory self reference entry.");
1043                 return 0;
1044         }
1045         if (MREF_LE(ie->data.dir.indexed_file) < FILE_first_user &&
1046                         !NVolShowSystemFiles(vol)) {
1047                 ntfs_debug("Skipping system file.");
1048                 return 0;
1049         }
1050         name_len = ntfs_ucstonls(vol, (ntfschar*)&ie->key.file_name.file_name,
1051                         ie->key.file_name.file_name_length, &name,
1052                         NTFS_MAX_NAME_LEN * NLS_MAX_CHARSET_SIZE + 1);
1053         if (name_len <= 0) {
1054                 ntfs_warning(vol->sb, "Skipping unrepresentable inode 0x%llx.",
1055                                 (long long)MREF_LE(ie->data.dir.indexed_file));
1056                 return 0;
1057         }
1058         if (ie->key.file_name.file_attributes &
1059                         FILE_ATTR_DUP_FILE_NAME_INDEX_PRESENT)
1060                 dt_type = DT_DIR;
1061         else
1062                 dt_type = DT_REG;
1063         mref = MREF_LE(ie->data.dir.indexed_file);
1064         /*
1065          * Drop the page lock otherwise we deadlock with NFS when it calls
1066          * ->lookup since ntfs_lookup() will lock the same page.
1067          */
1068         if (ia_page)
1069                 unlock_page(ia_page);
1070         ntfs_debug("Calling filldir for %s with len %i, fpos 0x%llx, inode "
1071                         "0x%lx, DT_%s.", name, name_len, fpos, mref,
1072                         dt_type == DT_DIR ? "DIR" : "REG");
1073         rc = filldir(dirent, name, name_len, fpos, mref, dt_type);
1074         /* Relock the page but not if we are aborting ->readdir. */
1075         if (!rc && ia_page)
1076                 lock_page(ia_page);
1077         return rc;
1078 }
1079
1080 /*
1081  * We use the same basic approach as the old NTFS driver, i.e. we parse the
1082  * index root entries and then the index allocation entries that are marked
1083  * as in use in the index bitmap.
1084  *
1085  * While this will return the names in random order this doesn't matter for
1086  * ->readdir but OTOH results in a faster ->readdir.
1087  *
1088  * VFS calls ->readdir without BKL but with i_mutex held. This protects the VFS
1089  * parts (e.g. ->f_pos and ->i_size, and it also protects against directory
1090  * modifications).
1091  *
1092  * Locking:  - Caller must hold i_mutex on the directory.
1093  *           - Each page cache page in the index allocation mapping must be
1094  *             locked whilst being accessed otherwise we may find a corrupt
1095  *             page due to it being under ->writepage at the moment which
1096  *             applies the mst protection fixups before writing out and then
1097  *             removes them again after the write is complete after which it
1098  *             unlocks the page.
1099  */
1100 static int ntfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
1101 {
1102         s64 ia_pos, ia_start, prev_ia_pos, bmp_pos;
1103         loff_t fpos, i_size;
1104         struct inode *bmp_vi, *vdir = filp->f_path.dentry->d_inode;
1105         struct super_block *sb = vdir->i_sb;
1106         ntfs_inode *ndir = NTFS_I(vdir);
1107         ntfs_volume *vol = NTFS_SB(sb);
1108         MFT_RECORD *m;
1109         INDEX_ROOT *ir = NULL;
1110         INDEX_ENTRY *ie;
1111         INDEX_ALLOCATION *ia;
1112         u8 *name = NULL;
1113         int rc, err, ir_pos, cur_bmp_pos;
1114         struct address_space *ia_mapping, *bmp_mapping;
1115         struct page *bmp_page = NULL, *ia_page = NULL;
1116         u8 *kaddr, *bmp, *index_end;
1117         ntfs_attr_search_ctx *ctx;
1118
1119         fpos = filp->f_pos;
1120         ntfs_debug("Entering for inode 0x%lx, fpos 0x%llx.",
1121                         vdir->i_ino, fpos);
1122         rc = err = 0;
1123         /* Are we at end of dir yet? */
1124         i_size = i_size_read(vdir);
1125         if (fpos >= i_size + vol->mft_record_size)
1126                 goto done;
1127         /* Emulate . and .. for all directories. */
1128         if (!fpos) {
1129                 ntfs_debug("Calling filldir for . with len 1, fpos 0x0, "
1130                                 "inode 0x%lx, DT_DIR.", vdir->i_ino);
1131                 rc = filldir(dirent, ".", 1, fpos, vdir->i_ino, DT_DIR);
1132                 if (rc)
1133                         goto done;
1134                 fpos++;
1135         }
1136         if (fpos == 1) {
1137                 ntfs_debug("Calling filldir for .. with len 2, fpos 0x1, "
1138                                 "inode 0x%lx, DT_DIR.",
1139                                 (unsigned long)parent_ino(filp->f_path.dentry));
1140                 rc = filldir(dirent, "..", 2, fpos,
1141                                 parent_ino(filp->f_path.dentry), DT_DIR);
1142                 if (rc)
1143                         goto done;
1144                 fpos++;
1145         }
1146         m = NULL;
1147         ctx = NULL;
1148         /*
1149          * Allocate a buffer to store the current name being processed
1150          * converted to format determined by current NLS.
1151          */
1152         name = kmalloc(NTFS_MAX_NAME_LEN * NLS_MAX_CHARSET_SIZE + 1, GFP_NOFS);
1153         if (unlikely(!name)) {
1154                 err = -ENOMEM;
1155                 goto err_out;
1156         }
1157         /* Are we jumping straight into the index allocation attribute? */
1158         if (fpos >= vol->mft_record_size)
1159                 goto skip_index_root;
1160         /* Get hold of the mft record for the directory. */
1161         m = map_mft_record(ndir);
1162         if (IS_ERR(m)) {
1163                 err = PTR_ERR(m);
1164                 m = NULL;
1165                 goto err_out;
1166         }
1167         ctx = ntfs_attr_get_search_ctx(ndir, m);
1168         if (unlikely(!ctx)) {
1169                 err = -ENOMEM;
1170                 goto err_out;
1171         }
1172         /* Get the offset into the index root attribute. */
1173         ir_pos = (s64)fpos;
1174         /* Find the index root attribute in the mft record. */
1175         err = ntfs_attr_lookup(AT_INDEX_ROOT, I30, 4, CASE_SENSITIVE, 0, NULL,
1176                         0, ctx);
1177         if (unlikely(err)) {
1178                 ntfs_error(sb, "Index root attribute missing in directory "
1179                                 "inode 0x%lx.", vdir->i_ino);
1180                 goto err_out;
1181         }
1182         /*
1183          * Copy the index root attribute value to a buffer so that we can put
1184          * the search context and unmap the mft record before calling the
1185          * filldir() callback.  We need to do this because of NFSd which calls
1186          * ->lookup() from its filldir callback() and this causes NTFS to
1187          * deadlock as ntfs_lookup() maps the mft record of the directory and
1188          * we have got it mapped here already.  The only solution is for us to
1189          * unmap the mft record here so that a call to ntfs_lookup() is able to
1190          * map the mft record without deadlocking.
1191          */
1192         rc = le32_to_cpu(ctx->attr->data.resident.value_length);
1193         ir = kmalloc(rc, GFP_NOFS);
1194         if (unlikely(!ir)) {
1195                 err = -ENOMEM;
1196                 goto err_out;
1197         }
1198         /* Copy the index root value (it has been verified in read_inode). */
1199         memcpy(ir, (u8*)ctx->attr +
1200                         le16_to_cpu(ctx->attr->data.resident.value_offset), rc);
1201         ntfs_attr_put_search_ctx(ctx);
1202         unmap_mft_record(ndir);
1203         ctx = NULL;
1204         m = NULL;
1205         index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
1206         /* The first index entry. */
1207         ie = (INDEX_ENTRY*)((u8*)&ir->index +
1208                         le32_to_cpu(ir->index.entries_offset));
1209         /*
1210          * Loop until we exceed valid memory (corruption case) or until we
1211          * reach the last entry or until filldir tells us it has had enough
1212          * or signals an error (both covered by the rc test).
1213          */
1214         for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
1215                 ntfs_debug("In index root, offset 0x%zx.", (u8*)ie - (u8*)ir);
1216                 /* Bounds checks. */
1217                 if (unlikely((u8*)ie < (u8*)ir || (u8*)ie +
1218                                 sizeof(INDEX_ENTRY_HEADER) > index_end ||
1219                                 (u8*)ie + le16_to_cpu(ie->key_length) >
1220                                 index_end))
1221                         goto err_out;
1222                 /* The last entry cannot contain a name. */
1223                 if (ie->flags & INDEX_ENTRY_END)
1224                         break;
1225                 /* Skip index root entry if continuing previous readdir. */
1226                 if (ir_pos > (u8*)ie - (u8*)ir)
1227                         continue;
1228                 /* Advance the position even if going to skip the entry. */
1229                 fpos = (u8*)ie - (u8*)ir;
1230                 /* Submit the name to the filldir callback. */
1231                 rc = ntfs_filldir(vol, fpos, ndir, NULL, ie, name, dirent,
1232                                 filldir);
1233                 if (rc) {
1234                         kfree(ir);
1235                         goto abort;
1236                 }
1237         }
1238         /* We are done with the index root and can free the buffer. */
1239         kfree(ir);
1240         ir = NULL;
1241         /* If there is no index allocation attribute we are finished. */
1242         if (!NInoIndexAllocPresent(ndir))
1243                 goto EOD;
1244         /* Advance fpos to the beginning of the index allocation. */
1245         fpos = vol->mft_record_size;
1246 skip_index_root:
1247         kaddr = NULL;
1248         prev_ia_pos = -1LL;
1249         /* Get the offset into the index allocation attribute. */
1250         ia_pos = (s64)fpos - vol->mft_record_size;
1251         ia_mapping = vdir->i_mapping;
1252         ntfs_debug("Inode 0x%lx, getting index bitmap.", vdir->i_ino);
1253         bmp_vi = ntfs_attr_iget(vdir, AT_BITMAP, I30, 4);
1254         if (IS_ERR(bmp_vi)) {
1255                 ntfs_error(sb, "Failed to get bitmap attribute.");
1256                 err = PTR_ERR(bmp_vi);
1257                 goto err_out;
1258         }
1259         bmp_mapping = bmp_vi->i_mapping;
1260         /* Get the starting bitmap bit position and sanity check it. */
1261         bmp_pos = ia_pos >> ndir->itype.index.block_size_bits;
1262         if (unlikely(bmp_pos >> 3 >= i_size_read(bmp_vi))) {
1263                 ntfs_error(sb, "Current index allocation position exceeds "
1264                                 "index bitmap size.");
1265                 goto iput_err_out;
1266         }
1267         /* Get the starting bit position in the current bitmap page. */
1268         cur_bmp_pos = bmp_pos & ((PAGE_CACHE_SIZE * 8) - 1);
1269         bmp_pos &= ~(u64)((PAGE_CACHE_SIZE * 8) - 1);
1270 get_next_bmp_page:
1271         ntfs_debug("Reading bitmap with page index 0x%llx, bit ofs 0x%llx",
1272                         (unsigned long long)bmp_pos >> (3 + PAGE_CACHE_SHIFT),
1273                         (unsigned long long)bmp_pos &
1274                         (unsigned long long)((PAGE_CACHE_SIZE * 8) - 1));
1275         bmp_page = ntfs_map_page(bmp_mapping,
1276                         bmp_pos >> (3 + PAGE_CACHE_SHIFT));
1277         if (IS_ERR(bmp_page)) {
1278                 ntfs_error(sb, "Reading index bitmap failed.");
1279                 err = PTR_ERR(bmp_page);
1280                 bmp_page = NULL;
1281                 goto iput_err_out;
1282         }
1283         bmp = (u8*)page_address(bmp_page);
1284         /* Find next index block in use. */
1285         while (!(bmp[cur_bmp_pos >> 3] & (1 << (cur_bmp_pos & 7)))) {
1286 find_next_index_buffer:
1287                 cur_bmp_pos++;
1288                 /*
1289                  * If we have reached the end of the bitmap page, get the next
1290                  * page, and put away the old one.
1291                  */
1292                 if (unlikely((cur_bmp_pos >> 3) >= PAGE_CACHE_SIZE)) {
1293                         ntfs_unmap_page(bmp_page);
1294                         bmp_pos += PAGE_CACHE_SIZE * 8;
1295                         cur_bmp_pos = 0;
1296                         goto get_next_bmp_page;
1297                 }
1298                 /* If we have reached the end of the bitmap, we are done. */
1299                 if (unlikely(((bmp_pos + cur_bmp_pos) >> 3) >= i_size))
1300                         goto unm_EOD;
1301                 ia_pos = (bmp_pos + cur_bmp_pos) <<
1302                                 ndir->itype.index.block_size_bits;
1303         }
1304         ntfs_debug("Handling index buffer 0x%llx.",
1305                         (unsigned long long)bmp_pos + cur_bmp_pos);
1306         /* If the current index buffer is in the same page we reuse the page. */
1307         if ((prev_ia_pos & (s64)PAGE_CACHE_MASK) !=
1308                         (ia_pos & (s64)PAGE_CACHE_MASK)) {
1309                 prev_ia_pos = ia_pos;
1310                 if (likely(ia_page != NULL)) {
1311                         unlock_page(ia_page);
1312                         ntfs_unmap_page(ia_page);
1313                 }
1314                 /*
1315                  * Map the page cache page containing the current ia_pos,
1316                  * reading it from disk if necessary.
1317                  */
1318                 ia_page = ntfs_map_page(ia_mapping, ia_pos >> PAGE_CACHE_SHIFT);
1319                 if (IS_ERR(ia_page)) {
1320                         ntfs_error(sb, "Reading index allocation data failed.");
1321                         err = PTR_ERR(ia_page);
1322                         ia_page = NULL;
1323                         goto err_out;
1324                 }
1325                 lock_page(ia_page);
1326                 kaddr = (u8*)page_address(ia_page);
1327         }
1328         /* Get the current index buffer. */
1329         ia = (INDEX_ALLOCATION*)(kaddr + (ia_pos & ~PAGE_CACHE_MASK &
1330                         ~(s64)(ndir->itype.index.block_size - 1)));
1331         /* Bounds checks. */
1332         if (unlikely((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_CACHE_SIZE)) {
1333                 ntfs_error(sb, "Out of bounds check failed. Corrupt directory "
1334                                 "inode 0x%lx or driver bug.", vdir->i_ino);
1335                 goto err_out;
1336         }
1337         /* Catch multi sector transfer fixup errors. */
1338         if (unlikely(!ntfs_is_indx_record(ia->magic))) {
1339                 ntfs_error(sb, "Directory index record with vcn 0x%llx is "
1340                                 "corrupt.  Corrupt inode 0x%lx.  Run chkdsk.",
1341                                 (unsigned long long)ia_pos >>
1342                                 ndir->itype.index.vcn_size_bits, vdir->i_ino);
1343                 goto err_out;
1344         }
1345         if (unlikely(sle64_to_cpu(ia->index_block_vcn) != (ia_pos &
1346                         ~(s64)(ndir->itype.index.block_size - 1)) >>
1347                         ndir->itype.index.vcn_size_bits)) {
1348                 ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is "
1349                                 "different from expected VCN (0x%llx). "
1350                                 "Directory inode 0x%lx is corrupt or driver "
1351                                 "bug. ", (unsigned long long)
1352                                 sle64_to_cpu(ia->index_block_vcn),
1353                                 (unsigned long long)ia_pos >>
1354                                 ndir->itype.index.vcn_size_bits, vdir->i_ino);
1355                 goto err_out;
1356         }
1357         if (unlikely(le32_to_cpu(ia->index.allocated_size) + 0x18 !=
1358                         ndir->itype.index.block_size)) {
1359                 ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
1360                                 "0x%lx has a size (%u) differing from the "
1361                                 "directory specified size (%u). Directory "
1362                                 "inode is corrupt or driver bug.",
1363                                 (unsigned long long)ia_pos >>
1364                                 ndir->itype.index.vcn_size_bits, vdir->i_ino,
1365                                 le32_to_cpu(ia->index.allocated_size) + 0x18,
1366                                 ndir->itype.index.block_size);
1367                 goto err_out;
1368         }
1369         index_end = (u8*)ia + ndir->itype.index.block_size;
1370         if (unlikely(index_end > kaddr + PAGE_CACHE_SIZE)) {
1371                 ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
1372                                 "0x%lx crosses page boundary. Impossible! "
1373                                 "Cannot access! This is probably a bug in the "
1374                                 "driver.", (unsigned long long)ia_pos >>
1375                                 ndir->itype.index.vcn_size_bits, vdir->i_ino);
1376                 goto err_out;
1377         }
1378         ia_start = ia_pos & ~(s64)(ndir->itype.index.block_size - 1);
1379         index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
1380         if (unlikely(index_end > (u8*)ia + ndir->itype.index.block_size)) {
1381                 ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of directory "
1382                                 "inode 0x%lx exceeds maximum size.",
1383                                 (unsigned long long)ia_pos >>
1384                                 ndir->itype.index.vcn_size_bits, vdir->i_ino);
1385                 goto err_out;
1386         }
1387         /* The first index entry in this index buffer. */
1388         ie = (INDEX_ENTRY*)((u8*)&ia->index +
1389                         le32_to_cpu(ia->index.entries_offset));
1390         /*
1391          * Loop until we exceed valid memory (corruption case) or until we
1392          * reach the last entry or until filldir tells us it has had enough
1393          * or signals an error (both covered by the rc test).
1394          */
1395         for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
1396                 ntfs_debug("In index allocation, offset 0x%llx.",
1397                                 (unsigned long long)ia_start +
1398                                 (unsigned long long)((u8*)ie - (u8*)ia));
1399                 /* Bounds checks. */
1400                 if (unlikely((u8*)ie < (u8*)ia || (u8*)ie +
1401                                 sizeof(INDEX_ENTRY_HEADER) > index_end ||
1402                                 (u8*)ie + le16_to_cpu(ie->key_length) >
1403                                 index_end))
1404                         goto err_out;
1405                 /* The last entry cannot contain a name. */
1406                 if (ie->flags & INDEX_ENTRY_END)
1407                         break;
1408                 /* Skip index block entry if continuing previous readdir. */
1409                 if (ia_pos - ia_start > (u8*)ie - (u8*)ia)
1410                         continue;
1411                 /* Advance the position even if going to skip the entry. */
1412                 fpos = (u8*)ie - (u8*)ia +
1413                                 (sle64_to_cpu(ia->index_block_vcn) <<
1414                                 ndir->itype.index.vcn_size_bits) +
1415                                 vol->mft_record_size;
1416                 /*
1417                  * Submit the name to the @filldir callback.  Note,
1418                  * ntfs_filldir() drops the lock on @ia_page but it retakes it
1419                  * before returning, unless a non-zero value is returned in
1420                  * which case the page is left unlocked.
1421                  */
1422                 rc = ntfs_filldir(vol, fpos, ndir, ia_page, ie, name, dirent,
1423                                 filldir);
1424                 if (rc) {
1425                         /* @ia_page is already unlocked in this case. */
1426                         ntfs_unmap_page(ia_page);
1427                         ntfs_unmap_page(bmp_page);
1428                         iput(bmp_vi);
1429                         goto abort;
1430                 }
1431         }
1432         goto find_next_index_buffer;
1433 unm_EOD:
1434         if (ia_page) {
1435                 unlock_page(ia_page);
1436                 ntfs_unmap_page(ia_page);
1437         }
1438         ntfs_unmap_page(bmp_page);
1439         iput(bmp_vi);
1440 EOD:
1441         /* We are finished, set fpos to EOD. */
1442         fpos = i_size + vol->mft_record_size;
1443 abort:
1444         kfree(name);
1445 done:
1446 #ifdef DEBUG
1447         if (!rc)
1448                 ntfs_debug("EOD, fpos 0x%llx, returning 0.", fpos);
1449         else
1450                 ntfs_debug("filldir returned %i, fpos 0x%llx, returning 0.",
1451                                 rc, fpos);
1452 #endif
1453         filp->f_pos = fpos;
1454         return 0;
1455 err_out:
1456         if (bmp_page) {
1457                 ntfs_unmap_page(bmp_page);
1458 iput_err_out:
1459                 iput(bmp_vi);
1460         }
1461         if (ia_page) {
1462                 unlock_page(ia_page);
1463                 ntfs_unmap_page(ia_page);
1464         }
1465         kfree(ir);
1466         kfree(name);
1467         if (ctx)
1468                 ntfs_attr_put_search_ctx(ctx);
1469         if (m)
1470                 unmap_mft_record(ndir);
1471         if (!err)
1472                 err = -EIO;
1473         ntfs_debug("Failed. Returning error code %i.", -err);
1474         filp->f_pos = fpos;
1475         return err;
1476 }
1477
1478 /**
1479  * ntfs_dir_open - called when an inode is about to be opened
1480  * @vi:         inode to be opened
1481  * @filp:       file structure describing the inode
1482  *
1483  * Limit directory size to the page cache limit on architectures where unsigned
1484  * long is 32-bits. This is the most we can do for now without overflowing the
1485  * page cache page index. Doing it this way means we don't run into problems
1486  * because of existing too large directories. It would be better to allow the
1487  * user to read the accessible part of the directory but I doubt very much
1488  * anyone is going to hit this check on a 32-bit architecture, so there is no
1489  * point in adding the extra complexity required to support this.
1490  *
1491  * On 64-bit architectures, the check is hopefully optimized away by the
1492  * compiler.
1493  */
1494 static int ntfs_dir_open(struct inode *vi, struct file *filp)
1495 {
1496         if (sizeof(unsigned long) < 8) {
1497                 if (i_size_read(vi) > MAX_LFS_FILESIZE)
1498                         return -EFBIG;
1499         }
1500         return 0;
1501 }
1502
1503 #ifdef NTFS_RW
1504
1505 /**
1506  * ntfs_dir_fsync - sync a directory to disk
1507  * @filp:       directory to be synced
1508  * @dentry:     dentry describing the directory to sync
1509  * @datasync:   if non-zero only flush user data and not metadata
1510  *
1511  * Data integrity sync of a directory to disk.  Used for fsync, fdatasync, and
1512  * msync system calls.  This function is based on file.c::ntfs_file_fsync().
1513  *
1514  * Write the mft record and all associated extent mft records as well as the
1515  * $INDEX_ALLOCATION and $BITMAP attributes and then sync the block device.
1516  *
1517  * If @datasync is true, we do not wait on the inode(s) to be written out
1518  * but we always wait on the page cache pages to be written out.
1519  *
1520  * Note: In the past @filp could be NULL so we ignore it as we don't need it
1521  * anyway.
1522  *
1523  * Locking: Caller must hold i_mutex on the inode.
1524  *
1525  * TODO: We should probably also write all attribute/index inodes associated
1526  * with this inode but since we have no simple way of getting to them we ignore
1527  * this problem for now.  We do write the $BITMAP attribute if it is present
1528  * which is the important one for a directory so things are not too bad.
1529  */
1530 static int ntfs_dir_fsync(struct file *filp, int datasync)
1531 {
1532         struct inode *bmp_vi, *vi = filp->f_mapping->host;
1533         int err, ret;
1534         ntfs_attr na;
1535
1536         ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
1537         BUG_ON(!S_ISDIR(vi->i_mode));
1538         /* If the bitmap attribute inode is in memory sync it, too. */
1539         na.mft_no = vi->i_ino;
1540         na.type = AT_BITMAP;
1541         na.name = I30;
1542         na.name_len = 4;
1543         bmp_vi = ilookup5(vi->i_sb, vi->i_ino, (test_t)ntfs_test_inode, &na);
1544         if (bmp_vi) {
1545                 write_inode_now(bmp_vi, !datasync);
1546                 iput(bmp_vi);
1547         }
1548         ret = __ntfs_write_inode(vi, 1);
1549         write_inode_now(vi, !datasync);
1550         err = sync_blockdev(vi->i_sb->s_bdev);
1551         if (unlikely(err && !ret))
1552                 ret = err;
1553         if (likely(!ret))
1554                 ntfs_debug("Done.");
1555         else
1556                 ntfs_warning(vi->i_sb, "Failed to f%ssync inode 0x%lx.  Error "
1557                                 "%u.", datasync ? "data" : "", vi->i_ino, -ret);
1558         return ret;
1559 }
1560
1561 #endif /* NTFS_RW */
1562
1563 const struct file_operations ntfs_dir_ops = {
1564         .llseek         = generic_file_llseek,  /* Seek inside directory. */
1565         .read           = generic_read_dir,     /* Return -EISDIR. */
1566         .readdir        = ntfs_readdir,         /* Read directory contents. */
1567 #ifdef NTFS_RW
1568         .fsync          = ntfs_dir_fsync,       /* Sync a directory to disk. */
1569         /*.aio_fsync    = ,*/                   /* Sync all outstanding async
1570                                                    i/o operations on a kiocb. */
1571 #endif /* NTFS_RW */
1572         /*.ioctl        = ,*/                   /* Perform function on the
1573                                                    mounted filesystem. */
1574         .open           = ntfs_dir_open,        /* Open directory. */
1575 };