linux/fs/ntfs/dir.c
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   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 $I30 as a global constant.
  35 */
  36ntfschar I30[5] = { cpu_to_le16('$'), 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 */
  80MFT_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)) {
 160found_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;
 315descend_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);
 331fast_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)) {
 420found_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;
 586unm_err_out:
 587        unlock_page(page);
 588        ntfs_unmap_page(page);
 589err_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);
 601dir_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 */
 633u64 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)) {
 722found_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;
 793descend_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);
 809fast_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)) {
 909found_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;
 986unm_err_out:
 987        unlock_page(page);
 988        ntfs_unmap_page(page);
 989err_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);
 997dir_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 */
1027static 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 */
1100static 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;
1246skip_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);
1270get_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)))) {
1286find_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;
1433unm_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);
1440EOD:
1441        /* We are finished, set fpos to EOD. */
1442        fpos = i_size + vol->mft_record_size;
1443abort:
1444        kfree(name);
1445done:
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;
1455err_out:
1456        if (bmp_page) {
1457                ntfs_unmap_page(bmp_page);
1458iput_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 */
1494static 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 */
1530static int ntfs_dir_fsync(struct file *filp, loff_t start, loff_t end,
1531                          int datasync)
1532{
1533        struct inode *bmp_vi, *vi = filp->f_mapping->host;
1534        int err, ret;
1535        ntfs_attr na;
1536
1537        ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
1538
1539        err = filemap_write_and_wait_range(vi->i_mapping, start, end);
1540        if (err)
1541                return err;
1542        mutex_lock(&vi->i_mutex);
1543
1544        BUG_ON(!S_ISDIR(vi->i_mode));
1545        /* If the bitmap attribute inode is in memory sync it, too. */
1546        na.mft_no = vi->i_ino;
1547        na.type = AT_BITMAP;
1548        na.name = I30;
1549        na.name_len = 4;
1550        bmp_vi = ilookup5(vi->i_sb, vi->i_ino, (test_t)ntfs_test_inode, &na);
1551        if (bmp_vi) {
1552                write_inode_now(bmp_vi, !datasync);
1553                iput(bmp_vi);
1554        }
1555        ret = __ntfs_write_inode(vi, 1);
1556        write_inode_now(vi, !datasync);
1557        err = sync_blockdev(vi->i_sb->s_bdev);
1558        if (unlikely(err && !ret))
1559                ret = err;
1560        if (likely(!ret))
1561                ntfs_debug("Done.");
1562        else
1563                ntfs_warning(vi->i_sb, "Failed to f%ssync inode 0x%lx.  Error "
1564                                "%u.", datasync ? "data" : "", vi->i_ino, -ret);
1565        mutex_unlock(&vi->i_mutex);
1566        return ret;
1567}
1568
1569#endif /* NTFS_RW */
1570
1571const struct file_operations ntfs_dir_ops = {
1572        .llseek         = generic_file_llseek,  /* Seek inside directory. */
1573        .read           = generic_read_dir,     /* Return -EISDIR. */
1574        .readdir        = ntfs_readdir,         /* Read directory contents. */
1575#ifdef NTFS_RW
1576        .fsync          = ntfs_dir_fsync,       /* Sync a directory to disk. */
1577        /*.aio_fsync    = ,*/                   /* Sync all outstanding async
1578                                                   i/o operations on a kiocb. */
1579#endif /* NTFS_RW */
1580        /*.ioctl        = ,*/                   /* Perform function on the
1581                                                   mounted filesystem. */
1582        .open           = ntfs_dir_open,        /* Open directory. */
1583};
1584
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