linux/fs/ntfs/logfile.c
<<
>>
Prefs
   1/*
   2 * logfile.c - NTFS kernel journal handling. Part of the Linux-NTFS project.
   3 *
   4 * Copyright (c) 2002-2007 Anton Altaparmakov
   5 *
   6 * This program/include file is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License as published
   8 * by the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program/include file is distributed in the hope that it will be
  12 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program (in the main directory of the Linux-NTFS
  18 * distribution in the file COPYING); if not, write to the Free Software
  19 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20 */
  21
  22#ifdef NTFS_RW
  23
  24#include <linux/types.h>
  25#include <linux/fs.h>
  26#include <linux/highmem.h>
  27#include <linux/buffer_head.h>
  28#include <linux/bitops.h>
  29#include <linux/log2.h>
  30
  31#include "attrib.h"
  32#include "aops.h"
  33#include "debug.h"
  34#include "logfile.h"
  35#include "malloc.h"
  36#include "volume.h"
  37#include "ntfs.h"
  38
  39/**
  40 * ntfs_check_restart_page_header - check the page header for consistency
  41 * @vi:         $LogFile inode to which the restart page header belongs
  42 * @rp:         restart page header to check
  43 * @pos:        position in @vi at which the restart page header resides
  44 *
  45 * Check the restart page header @rp for consistency and return 'true' if it is
  46 * consistent and 'false' otherwise.
  47 *
  48 * This function only needs NTFS_BLOCK_SIZE bytes in @rp, i.e. it does not
  49 * require the full restart page.
  50 */
  51static bool ntfs_check_restart_page_header(struct inode *vi,
  52                RESTART_PAGE_HEADER *rp, s64 pos)
  53{
  54        u32 logfile_system_page_size, logfile_log_page_size;
  55        u16 ra_ofs, usa_count, usa_ofs, usa_end = 0;
  56        bool have_usa = true;
  57
  58        ntfs_debug("Entering.");
  59        /*
  60         * If the system or log page sizes are smaller than the ntfs block size
  61         * or either is not a power of 2 we cannot handle this log file.
  62         */
  63        logfile_system_page_size = le32_to_cpu(rp->system_page_size);
  64        logfile_log_page_size = le32_to_cpu(rp->log_page_size);
  65        if (logfile_system_page_size < NTFS_BLOCK_SIZE ||
  66                        logfile_log_page_size < NTFS_BLOCK_SIZE ||
  67                        logfile_system_page_size &
  68                        (logfile_system_page_size - 1) ||
  69                        !is_power_of_2(logfile_log_page_size)) {
  70                ntfs_error(vi->i_sb, "$LogFile uses unsupported page size.");
  71                return false;
  72        }
  73        /*
  74         * We must be either at !pos (1st restart page) or at pos = system page
  75         * size (2nd restart page).
  76         */
  77        if (pos && pos != logfile_system_page_size) {
  78                ntfs_error(vi->i_sb, "Found restart area in incorrect "
  79                                "position in $LogFile.");
  80                return false;
  81        }
  82        /* We only know how to handle version 1.1. */
  83        if (sle16_to_cpu(rp->major_ver) != 1 ||
  84                        sle16_to_cpu(rp->minor_ver) != 1) {
  85                ntfs_error(vi->i_sb, "$LogFile version %i.%i is not "
  86                                "supported.  (This driver supports version "
  87                                "1.1 only.)", (int)sle16_to_cpu(rp->major_ver),
  88                                (int)sle16_to_cpu(rp->minor_ver));
  89                return false;
  90        }
  91        /*
  92         * If chkdsk has been run the restart page may not be protected by an
  93         * update sequence array.
  94         */
  95        if (ntfs_is_chkd_record(rp->magic) && !le16_to_cpu(rp->usa_count)) {
  96                have_usa = false;
  97                goto skip_usa_checks;
  98        }
  99        /* Verify the size of the update sequence array. */
 100        usa_count = 1 + (logfile_system_page_size >> NTFS_BLOCK_SIZE_BITS);
 101        if (usa_count != le16_to_cpu(rp->usa_count)) {
 102                ntfs_error(vi->i_sb, "$LogFile restart page specifies "
 103                                "inconsistent update sequence array count.");
 104                return false;
 105        }
 106        /* Verify the position of the update sequence array. */
 107        usa_ofs = le16_to_cpu(rp->usa_ofs);
 108        usa_end = usa_ofs + usa_count * sizeof(u16);
 109        if (usa_ofs < sizeof(RESTART_PAGE_HEADER) ||
 110                        usa_end > NTFS_BLOCK_SIZE - sizeof(u16)) {
 111                ntfs_error(vi->i_sb, "$LogFile restart page specifies "
 112                                "inconsistent update sequence array offset.");
 113                return false;
 114        }
 115skip_usa_checks:
 116        /*
 117         * Verify the position of the restart area.  It must be:
 118         *      - aligned to 8-byte boundary,
 119         *      - after the update sequence array, and
 120         *      - within the system page size.
 121         */
 122        ra_ofs = le16_to_cpu(rp->restart_area_offset);
 123        if (ra_ofs & 7 || (have_usa ? ra_ofs < usa_end :
 124                        ra_ofs < sizeof(RESTART_PAGE_HEADER)) ||
 125                        ra_ofs > logfile_system_page_size) {
 126                ntfs_error(vi->i_sb, "$LogFile restart page specifies "
 127                                "inconsistent restart area offset.");
 128                return false;
 129        }
 130        /*
 131         * Only restart pages modified by chkdsk are allowed to have chkdsk_lsn
 132         * set.
 133         */
 134        if (!ntfs_is_chkd_record(rp->magic) && sle64_to_cpu(rp->chkdsk_lsn)) {
 135                ntfs_error(vi->i_sb, "$LogFile restart page is not modified "
 136                                "by chkdsk but a chkdsk LSN is specified.");
 137                return false;
 138        }
 139        ntfs_debug("Done.");
 140        return true;
 141}
 142
 143/**
 144 * ntfs_check_restart_area - check the restart area for consistency
 145 * @vi:         $LogFile inode to which the restart page belongs
 146 * @rp:         restart page whose restart area to check
 147 *
 148 * Check the restart area of the restart page @rp for consistency and return
 149 * 'true' if it is consistent and 'false' otherwise.
 150 *
 151 * This function assumes that the restart page header has already been
 152 * consistency checked.
 153 *
 154 * This function only needs NTFS_BLOCK_SIZE bytes in @rp, i.e. it does not
 155 * require the full restart page.
 156 */
 157static bool ntfs_check_restart_area(struct inode *vi, RESTART_PAGE_HEADER *rp)
 158{
 159        u64 file_size;
 160        RESTART_AREA *ra;
 161        u16 ra_ofs, ra_len, ca_ofs;
 162        u8 fs_bits;
 163
 164        ntfs_debug("Entering.");
 165        ra_ofs = le16_to_cpu(rp->restart_area_offset);
 166        ra = (RESTART_AREA*)((u8*)rp + ra_ofs);
 167        /*
 168         * Everything before ra->file_size must be before the first word
 169         * protected by an update sequence number.  This ensures that it is
 170         * safe to access ra->client_array_offset.
 171         */
 172        if (ra_ofs + offsetof(RESTART_AREA, file_size) >
 173                        NTFS_BLOCK_SIZE - sizeof(u16)) {
 174                ntfs_error(vi->i_sb, "$LogFile restart area specifies "
 175                                "inconsistent file offset.");
 176                return false;
 177        }
 178        /*
 179         * Now that we can access ra->client_array_offset, make sure everything
 180         * up to the log client array is before the first word protected by an
 181         * update sequence number.  This ensures we can access all of the
 182         * restart area elements safely.  Also, the client array offset must be
 183         * aligned to an 8-byte boundary.
 184         */
 185        ca_ofs = le16_to_cpu(ra->client_array_offset);
 186        if (((ca_ofs + 7) & ~7) != ca_ofs ||
 187                        ra_ofs + ca_ofs > NTFS_BLOCK_SIZE - sizeof(u16)) {
 188                ntfs_error(vi->i_sb, "$LogFile restart area specifies "
 189                                "inconsistent client array offset.");
 190                return false;
 191        }
 192        /*
 193         * The restart area must end within the system page size both when
 194         * calculated manually and as specified by ra->restart_area_length.
 195         * Also, the calculated length must not exceed the specified length.
 196         */
 197        ra_len = ca_ofs + le16_to_cpu(ra->log_clients) *
 198                        sizeof(LOG_CLIENT_RECORD);
 199        if (ra_ofs + ra_len > le32_to_cpu(rp->system_page_size) ||
 200                        ra_ofs + le16_to_cpu(ra->restart_area_length) >
 201                        le32_to_cpu(rp->system_page_size) ||
 202                        ra_len > le16_to_cpu(ra->restart_area_length)) {
 203                ntfs_error(vi->i_sb, "$LogFile restart area is out of bounds "
 204                                "of the system page size specified by the "
 205                                "restart page header and/or the specified "
 206                                "restart area length is inconsistent.");
 207                return false;
 208        }
 209        /*
 210         * The ra->client_free_list and ra->client_in_use_list must be either
 211         * LOGFILE_NO_CLIENT or less than ra->log_clients or they are
 212         * overflowing the client array.
 213         */
 214        if ((ra->client_free_list != LOGFILE_NO_CLIENT &&
 215                        le16_to_cpu(ra->client_free_list) >=
 216                        le16_to_cpu(ra->log_clients)) ||
 217                        (ra->client_in_use_list != LOGFILE_NO_CLIENT &&
 218                        le16_to_cpu(ra->client_in_use_list) >=
 219                        le16_to_cpu(ra->log_clients))) {
 220                ntfs_error(vi->i_sb, "$LogFile restart area specifies "
 221                                "overflowing client free and/or in use lists.");
 222                return false;
 223        }
 224        /*
 225         * Check ra->seq_number_bits against ra->file_size for consistency.
 226         * We cannot just use ffs() because the file size is not a power of 2.
 227         */
 228        file_size = (u64)sle64_to_cpu(ra->file_size);
 229        fs_bits = 0;
 230        while (file_size) {
 231                file_size >>= 1;
 232                fs_bits++;
 233        }
 234        if (le32_to_cpu(ra->seq_number_bits) != 67 - fs_bits) {
 235                ntfs_error(vi->i_sb, "$LogFile restart area specifies "
 236                                "inconsistent sequence number bits.");
 237                return false;
 238        }
 239        /* The log record header length must be a multiple of 8. */
 240        if (((le16_to_cpu(ra->log_record_header_length) + 7) & ~7) !=
 241                        le16_to_cpu(ra->log_record_header_length)) {
 242                ntfs_error(vi->i_sb, "$LogFile restart area specifies "
 243                                "inconsistent log record header length.");
 244                return false;
 245        }
 246        /* Dito for the log page data offset. */
 247        if (((le16_to_cpu(ra->log_page_data_offset) + 7) & ~7) !=
 248                        le16_to_cpu(ra->log_page_data_offset)) {
 249                ntfs_error(vi->i_sb, "$LogFile restart area specifies "
 250                                "inconsistent log page data offset.");
 251                return false;
 252        }
 253        ntfs_debug("Done.");
 254        return true;
 255}
 256
 257/**
 258 * ntfs_check_log_client_array - check the log client array for consistency
 259 * @vi:         $LogFile inode to which the restart page belongs
 260 * @rp:         restart page whose log client array to check
 261 *
 262 * Check the log client array of the restart page @rp for consistency and
 263 * return 'true' if it is consistent and 'false' otherwise.
 264 *
 265 * This function assumes that the restart page header and the restart area have
 266 * already been consistency checked.
 267 *
 268 * Unlike ntfs_check_restart_page_header() and ntfs_check_restart_area(), this
 269 * function needs @rp->system_page_size bytes in @rp, i.e. it requires the full
 270 * restart page and the page must be multi sector transfer deprotected.
 271 */
 272static bool ntfs_check_log_client_array(struct inode *vi,
 273                RESTART_PAGE_HEADER *rp)
 274{
 275        RESTART_AREA *ra;
 276        LOG_CLIENT_RECORD *ca, *cr;
 277        u16 nr_clients, idx;
 278        bool in_free_list, idx_is_first;
 279
 280        ntfs_debug("Entering.");
 281        ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
 282        ca = (LOG_CLIENT_RECORD*)((u8*)ra +
 283                        le16_to_cpu(ra->client_array_offset));
 284        /*
 285         * Check the ra->client_free_list first and then check the
 286         * ra->client_in_use_list.  Check each of the log client records in
 287         * each of the lists and check that the array does not overflow the
 288         * ra->log_clients value.  Also keep track of the number of records
 289         * visited as there cannot be more than ra->log_clients records and
 290         * that way we detect eventual loops in within a list.
 291         */
 292        nr_clients = le16_to_cpu(ra->log_clients);
 293        idx = le16_to_cpu(ra->client_free_list);
 294        in_free_list = true;
 295check_list:
 296        for (idx_is_first = true; idx != LOGFILE_NO_CLIENT_CPU; nr_clients--,
 297                        idx = le16_to_cpu(cr->next_client)) {
 298                if (!nr_clients || idx >= le16_to_cpu(ra->log_clients))
 299                        goto err_out;
 300                /* Set @cr to the current log client record. */
 301                cr = ca + idx;
 302                /* The first log client record must not have a prev_client. */
 303                if (idx_is_first) {
 304                        if (cr->prev_client != LOGFILE_NO_CLIENT)
 305                                goto err_out;
 306                        idx_is_first = false;
 307                }
 308        }
 309        /* Switch to and check the in use list if we just did the free list. */
 310        if (in_free_list) {
 311                in_free_list = false;
 312                idx = le16_to_cpu(ra->client_in_use_list);
 313                goto check_list;
 314        }
 315        ntfs_debug("Done.");
 316        return true;
 317err_out:
 318        ntfs_error(vi->i_sb, "$LogFile log client array is corrupt.");
 319        return false;
 320}
 321
 322/**
 323 * ntfs_check_and_load_restart_page - check the restart page for consistency
 324 * @vi:         $LogFile inode to which the restart page belongs
 325 * @rp:         restart page to check
 326 * @pos:        position in @vi at which the restart page resides
 327 * @wrp:        [OUT] copy of the multi sector transfer deprotected restart page
 328 * @lsn:        [OUT] set to the current logfile lsn on success
 329 *
 330 * Check the restart page @rp for consistency and return 0 if it is consistent
 331 * and -errno otherwise.  The restart page may have been modified by chkdsk in
 332 * which case its magic is CHKD instead of RSTR.
 333 *
 334 * This function only needs NTFS_BLOCK_SIZE bytes in @rp, i.e. it does not
 335 * require the full restart page.
 336 *
 337 * If @wrp is not NULL, on success, *@wrp will point to a buffer containing a
 338 * copy of the complete multi sector transfer deprotected page.  On failure,
 339 * *@wrp is undefined.
 340 *
 341 * Simillarly, if @lsn is not NULL, on success *@lsn will be set to the current
 342 * logfile lsn according to this restart page.  On failure, *@lsn is undefined.
 343 *
 344 * The following error codes are defined:
 345 *      -EINVAL - The restart page is inconsistent.
 346 *      -ENOMEM - Not enough memory to load the restart page.
 347 *      -EIO    - Failed to reading from $LogFile.
 348 */
 349static int ntfs_check_and_load_restart_page(struct inode *vi,
 350                RESTART_PAGE_HEADER *rp, s64 pos, RESTART_PAGE_HEADER **wrp,
 351                LSN *lsn)
 352{
 353        RESTART_AREA *ra;
 354        RESTART_PAGE_HEADER *trp;
 355        int size, err;
 356
 357        ntfs_debug("Entering.");
 358        /* Check the restart page header for consistency. */
 359        if (!ntfs_check_restart_page_header(vi, rp, pos)) {
 360                /* Error output already done inside the function. */
 361                return -EINVAL;
 362        }
 363        /* Check the restart area for consistency. */
 364        if (!ntfs_check_restart_area(vi, rp)) {
 365                /* Error output already done inside the function. */
 366                return -EINVAL;
 367        }
 368        ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
 369        /*
 370         * Allocate a buffer to store the whole restart page so we can multi
 371         * sector transfer deprotect it.
 372         */
 373        trp = ntfs_malloc_nofs(le32_to_cpu(rp->system_page_size));
 374        if (!trp) {
 375                ntfs_error(vi->i_sb, "Failed to allocate memory for $LogFile "
 376                                "restart page buffer.");
 377                return -ENOMEM;
 378        }
 379        /*
 380         * Read the whole of the restart page into the buffer.  If it fits
 381         * completely inside @rp, just copy it from there.  Otherwise map all
 382         * the required pages and copy the data from them.
 383         */
 384        size = PAGE_CACHE_SIZE - (pos & ~PAGE_CACHE_MASK);
 385        if (size >= le32_to_cpu(rp->system_page_size)) {
 386                memcpy(trp, rp, le32_to_cpu(rp->system_page_size));
 387        } else {
 388                pgoff_t idx;
 389                struct page *page;
 390                int have_read, to_read;
 391
 392                /* First copy what we already have in @rp. */
 393                memcpy(trp, rp, size);
 394                /* Copy the remaining data one page at a time. */
 395                have_read = size;
 396                to_read = le32_to_cpu(rp->system_page_size) - size;
 397                idx = (pos + size) >> PAGE_CACHE_SHIFT;
 398                BUG_ON((pos + size) & ~PAGE_CACHE_MASK);
 399                do {
 400                        page = ntfs_map_page(vi->i_mapping, idx);
 401                        if (IS_ERR(page)) {
 402                                ntfs_error(vi->i_sb, "Error mapping $LogFile "
 403                                                "page (index %lu).", idx);
 404                                err = PTR_ERR(page);
 405                                if (err != -EIO && err != -ENOMEM)
 406                                        err = -EIO;
 407                                goto err_out;
 408                        }
 409                        size = min_t(int, to_read, PAGE_CACHE_SIZE);
 410                        memcpy((u8*)trp + have_read, page_address(page), size);
 411                        ntfs_unmap_page(page);
 412                        have_read += size;
 413                        to_read -= size;
 414                        idx++;
 415                } while (to_read > 0);
 416        }
 417        /*
 418         * Perform the multi sector transfer deprotection on the buffer if the
 419         * restart page is protected.
 420         */
 421        if ((!ntfs_is_chkd_record(trp->magic) || le16_to_cpu(trp->usa_count))
 422                        && post_read_mst_fixup((NTFS_RECORD*)trp,
 423                        le32_to_cpu(rp->system_page_size))) {
 424                /*
 425                 * A multi sector tranfer error was detected.  We only need to
 426                 * abort if the restart page contents exceed the multi sector
 427                 * transfer fixup of the first sector.
 428                 */
 429                if (le16_to_cpu(rp->restart_area_offset) +
 430                                le16_to_cpu(ra->restart_area_length) >
 431                                NTFS_BLOCK_SIZE - sizeof(u16)) {
 432                        ntfs_error(vi->i_sb, "Multi sector transfer error "
 433                                        "detected in $LogFile restart page.");
 434                        err = -EINVAL;
 435                        goto err_out;
 436                }
 437        }
 438        /*
 439         * If the restart page is modified by chkdsk or there are no active
 440         * logfile clients, the logfile is consistent.  Otherwise, need to
 441         * check the log client records for consistency, too.
 442         */
 443        err = 0;
 444        if (ntfs_is_rstr_record(rp->magic) &&
 445                        ra->client_in_use_list != LOGFILE_NO_CLIENT) {
 446                if (!ntfs_check_log_client_array(vi, trp)) {
 447                        err = -EINVAL;
 448                        goto err_out;
 449                }
 450        }
 451        if (lsn) {
 452                if (ntfs_is_rstr_record(rp->magic))
 453                        *lsn = sle64_to_cpu(ra->current_lsn);
 454                else /* if (ntfs_is_chkd_record(rp->magic)) */
 455                        *lsn = sle64_to_cpu(rp->chkdsk_lsn);
 456        }
 457        ntfs_debug("Done.");
 458        if (wrp)
 459                *wrp = trp;
 460        else {
 461err_out:
 462                ntfs_free(trp);
 463        }
 464        return err;
 465}
 466
 467/**
 468 * ntfs_check_logfile - check the journal for consistency
 469 * @log_vi:     struct inode of loaded journal $LogFile to check
 470 * @rp:         [OUT] on success this is a copy of the current restart page
 471 *
 472 * Check the $LogFile journal for consistency and return 'true' if it is
 473 * consistent and 'false' if not.  On success, the current restart page is
 474 * returned in *@rp.  Caller must call ntfs_free(*@rp) when finished with it.
 475 *
 476 * At present we only check the two restart pages and ignore the log record
 477 * pages.
 478 *
 479 * Note that the MstProtected flag is not set on the $LogFile inode and hence
 480 * when reading pages they are not deprotected.  This is because we do not know
 481 * if the $LogFile was created on a system with a different page size to ours
 482 * yet and mst deprotection would fail if our page size is smaller.
 483 */
 484bool ntfs_check_logfile(struct inode *log_vi, RESTART_PAGE_HEADER **rp)
 485{
 486        s64 size, pos;
 487        LSN rstr1_lsn, rstr2_lsn;
 488        ntfs_volume *vol = NTFS_SB(log_vi->i_sb);
 489        struct address_space *mapping = log_vi->i_mapping;
 490        struct page *page = NULL;
 491        u8 *kaddr = NULL;
 492        RESTART_PAGE_HEADER *rstr1_ph = NULL;
 493        RESTART_PAGE_HEADER *rstr2_ph = NULL;
 494        int log_page_size, log_page_mask, err;
 495        bool logfile_is_empty = true;
 496        u8 log_page_bits;
 497
 498        ntfs_debug("Entering.");
 499        /* An empty $LogFile must have been clean before it got emptied. */
 500        if (NVolLogFileEmpty(vol))
 501                goto is_empty;
 502        size = i_size_read(log_vi);
 503        /* Make sure the file doesn't exceed the maximum allowed size. */
 504        if (size > MaxLogFileSize)
 505                size = MaxLogFileSize;
 506        /*
 507         * Truncate size to a multiple of the page cache size or the default
 508         * log page size if the page cache size is between the default log page
 509         * log page size if the page cache size is between the default log page
 510         * size and twice that.
 511         */
 512        if (PAGE_CACHE_SIZE >= DefaultLogPageSize && PAGE_CACHE_SIZE <=
 513                        DefaultLogPageSize * 2)
 514                log_page_size = DefaultLogPageSize;
 515        else
 516                log_page_size = PAGE_CACHE_SIZE;
 517        log_page_mask = log_page_size - 1;
 518        /*
 519         * Use ntfs_ffs() instead of ffs() to enable the compiler to
 520         * optimize log_page_size and log_page_bits into constants.
 521         */
 522        log_page_bits = ntfs_ffs(log_page_size) - 1;
 523        size &= ~(s64)(log_page_size - 1);
 524        /*
 525         * Ensure the log file is big enough to store at least the two restart
 526         * pages and the minimum number of log record pages.
 527         */
 528        if (size < log_page_size * 2 || (size - log_page_size * 2) >>
 529                        log_page_bits < MinLogRecordPages) {
 530                ntfs_error(vol->sb, "$LogFile is too small.");
 531                return false;
 532        }
 533        /*
 534         * Read through the file looking for a restart page.  Since the restart
 535         * page header is at the beginning of a page we only need to search at
 536         * what could be the beginning of a page (for each page size) rather
 537         * than scanning the whole file byte by byte.  If all potential places
 538         * contain empty and uninitialzed records, the log file can be assumed
 539         * to be empty.
 540         */
 541        for (pos = 0; pos < size; pos <<= 1) {
 542                pgoff_t idx = pos >> PAGE_CACHE_SHIFT;
 543                if (!page || page->index != idx) {
 544                        if (page)
 545                                ntfs_unmap_page(page);
 546                        page = ntfs_map_page(mapping, idx);
 547                        if (IS_ERR(page)) {
 548                                ntfs_error(vol->sb, "Error mapping $LogFile "
 549                                                "page (index %lu).", idx);
 550                                goto err_out;
 551                        }
 552                }
 553                kaddr = (u8*)page_address(page) + (pos & ~PAGE_CACHE_MASK);
 554                /*
 555                 * A non-empty block means the logfile is not empty while an
 556                 * empty block after a non-empty block has been encountered
 557                 * means we are done.
 558                 */
 559                if (!ntfs_is_empty_recordp((le32*)kaddr))
 560                        logfile_is_empty = false;
 561                else if (!logfile_is_empty)
 562                        break;
 563                /*
 564                 * A log record page means there cannot be a restart page after
 565                 * this so no need to continue searching.
 566                 */
 567                if (ntfs_is_rcrd_recordp((le32*)kaddr))
 568                        break;
 569                /* If not a (modified by chkdsk) restart page, continue. */
 570                if (!ntfs_is_rstr_recordp((le32*)kaddr) &&
 571                                !ntfs_is_chkd_recordp((le32*)kaddr)) {
 572                        if (!pos)
 573                                pos = NTFS_BLOCK_SIZE >> 1;
 574                        continue;
 575                }
 576                /*
 577                 * Check the (modified by chkdsk) restart page for consistency
 578                 * and get a copy of the complete multi sector transfer
 579                 * deprotected restart page.
 580                 */
 581                err = ntfs_check_and_load_restart_page(log_vi,
 582                                (RESTART_PAGE_HEADER*)kaddr, pos,
 583                                !rstr1_ph ? &rstr1_ph : &rstr2_ph,
 584                                !rstr1_ph ? &rstr1_lsn : &rstr2_lsn);
 585                if (!err) {
 586                        /*
 587                         * If we have now found the first (modified by chkdsk)
 588                         * restart page, continue looking for the second one.
 589                         */
 590                        if (!pos) {
 591                                pos = NTFS_BLOCK_SIZE >> 1;
 592                                continue;
 593                        }
 594                        /*
 595                         * We have now found the second (modified by chkdsk)
 596                         * restart page, so we can stop looking.
 597                         */
 598                        break;
 599                }
 600                /*
 601                 * Error output already done inside the function.  Note, we do
 602                 * not abort if the restart page was invalid as we might still
 603                 * find a valid one further in the file.
 604                 */
 605                if (err != -EINVAL) {
 606                        ntfs_unmap_page(page);
 607                        goto err_out;
 608                }
 609                /* Continue looking. */
 610                if (!pos)
 611                        pos = NTFS_BLOCK_SIZE >> 1;
 612        }
 613        if (page)
 614                ntfs_unmap_page(page);
 615        if (logfile_is_empty) {
 616                NVolSetLogFileEmpty(vol);
 617is_empty:
 618                ntfs_debug("Done.  ($LogFile is empty.)");
 619                return true;
 620        }
 621        if (!rstr1_ph) {
 622                BUG_ON(rstr2_ph);
 623                ntfs_error(vol->sb, "Did not find any restart pages in "
 624                                "$LogFile and it was not empty.");
 625                return false;
 626        }
 627        /* If both restart pages were found, use the more recent one. */
 628        if (rstr2_ph) {
 629                /*
 630                 * If the second restart area is more recent, switch to it.
 631                 * Otherwise just throw it away.
 632                 */
 633                if (rstr2_lsn > rstr1_lsn) {
 634                        ntfs_debug("Using second restart page as it is more "
 635                                        "recent.");
 636                        ntfs_free(rstr1_ph);
 637                        rstr1_ph = rstr2_ph;
 638                        /* rstr1_lsn = rstr2_lsn; */
 639                } else {
 640                        ntfs_debug("Using first restart page as it is more "
 641                                        "recent.");
 642                        ntfs_free(rstr2_ph);
 643                }
 644                rstr2_ph = NULL;
 645        }
 646        /* All consistency checks passed. */
 647        if (rp)
 648                *rp = rstr1_ph;
 649        else
 650                ntfs_free(rstr1_ph);
 651        ntfs_debug("Done.");
 652        return true;
 653err_out:
 654        if (rstr1_ph)
 655                ntfs_free(rstr1_ph);
 656        return false;
 657}
 658
 659/**
 660 * ntfs_is_logfile_clean - check in the journal if the volume is clean
 661 * @log_vi:     struct inode of loaded journal $LogFile to check
 662 * @rp:         copy of the current restart page
 663 *
 664 * Analyze the $LogFile journal and return 'true' if it indicates the volume was
 665 * shutdown cleanly and 'false' if not.
 666 *
 667 * At present we only look at the two restart pages and ignore the log record
 668 * pages.  This is a little bit crude in that there will be a very small number
 669 * of cases where we think that a volume is dirty when in fact it is clean.
 670 * This should only affect volumes that have not been shutdown cleanly but did
 671 * not have any pending, non-check-pointed i/o, i.e. they were completely idle
 672 * at least for the five seconds preceding the unclean shutdown.
 673 *
 674 * This function assumes that the $LogFile journal has already been consistency
 675 * checked by a call to ntfs_check_logfile() and in particular if the $LogFile
 676 * is empty this function requires that NVolLogFileEmpty() is true otherwise an
 677 * empty volume will be reported as dirty.
 678 */
 679bool ntfs_is_logfile_clean(struct inode *log_vi, const RESTART_PAGE_HEADER *rp)
 680{
 681        ntfs_volume *vol = NTFS_SB(log_vi->i_sb);
 682        RESTART_AREA *ra;
 683
 684        ntfs_debug("Entering.");
 685        /* An empty $LogFile must have been clean before it got emptied. */
 686        if (NVolLogFileEmpty(vol)) {
 687                ntfs_debug("Done.  ($LogFile is empty.)");
 688                return true;
 689        }
 690        BUG_ON(!rp);
 691        if (!ntfs_is_rstr_record(rp->magic) &&
 692                        !ntfs_is_chkd_record(rp->magic)) {
 693                ntfs_error(vol->sb, "Restart page buffer is invalid.  This is "
 694                                "probably a bug in that the $LogFile should "
 695                                "have been consistency checked before calling "
 696                                "this function.");
 697                return false;
 698        }
 699        ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
 700        /*
 701         * If the $LogFile has active clients, i.e. it is open, and we do not
 702         * have the RESTART_VOLUME_IS_CLEAN bit set in the restart area flags,
 703         * we assume there was an unclean shutdown.
 704         */
 705        if (ra->client_in_use_list != LOGFILE_NO_CLIENT &&
 706                        !(ra->flags & RESTART_VOLUME_IS_CLEAN)) {
 707                ntfs_debug("Done.  $LogFile indicates a dirty shutdown.");
 708                return false;
 709        }
 710        /* $LogFile indicates a clean shutdown. */
 711        ntfs_debug("Done.  $LogFile indicates a clean shutdown.");
 712        return true;
 713}
 714
 715/**
 716 * ntfs_empty_logfile - empty the contents of the $LogFile journal
 717 * @log_vi:     struct inode of loaded journal $LogFile to empty
 718 *
 719 * Empty the contents of the $LogFile journal @log_vi and return 'true' on
 720 * success and 'false' on error.
 721 *
 722 * This function assumes that the $LogFile journal has already been consistency
 723 * checked by a call to ntfs_check_logfile() and that ntfs_is_logfile_clean()
 724 * has been used to ensure that the $LogFile is clean.
 725 */
 726bool ntfs_empty_logfile(struct inode *log_vi)
 727{
 728        VCN vcn, end_vcn;
 729        ntfs_inode *log_ni = NTFS_I(log_vi);
 730        ntfs_volume *vol = log_ni->vol;
 731        struct super_block *sb = vol->sb;
 732        runlist_element *rl;
 733        unsigned long flags;
 734        unsigned block_size, block_size_bits;
 735        int err;
 736        bool should_wait = true;
 737
 738        ntfs_debug("Entering.");
 739        if (NVolLogFileEmpty(vol)) {
 740                ntfs_debug("Done.");
 741                return true;
 742        }
 743        /*
 744         * We cannot use ntfs_attr_set() because we may be still in the middle
 745         * of a mount operation.  Thus we do the emptying by hand by first
 746         * zapping the page cache pages for the $LogFile/$DATA attribute and
 747         * then emptying each of the buffers in each of the clusters specified
 748         * by the runlist by hand.
 749         */
 750        block_size = sb->s_blocksize;
 751        block_size_bits = sb->s_blocksize_bits;
 752        vcn = 0;
 753        read_lock_irqsave(&log_ni->size_lock, flags);
 754        end_vcn = (log_ni->initialized_size + vol->cluster_size_mask) >>
 755                        vol->cluster_size_bits;
 756        read_unlock_irqrestore(&log_ni->size_lock, flags);
 757        truncate_inode_pages(log_vi->i_mapping, 0);
 758        down_write(&log_ni->runlist.lock);
 759        rl = log_ni->runlist.rl;
 760        if (unlikely(!rl || vcn < rl->vcn || !rl->length)) {
 761map_vcn:
 762                err = ntfs_map_runlist_nolock(log_ni, vcn, NULL);
 763                if (err) {
 764                        ntfs_error(sb, "Failed to map runlist fragment (error "
 765                                        "%d).", -err);
 766                        goto err;
 767                }
 768                rl = log_ni->runlist.rl;
 769                BUG_ON(!rl || vcn < rl->vcn || !rl->length);
 770        }
 771        /* Seek to the runlist element containing @vcn. */
 772        while (rl->length && vcn >= rl[1].vcn)
 773                rl++;
 774        do {
 775                LCN lcn;
 776                sector_t block, end_block;
 777                s64 len;
 778
 779                /*
 780                 * If this run is not mapped map it now and start again as the
 781                 * runlist will have been updated.
 782                 */
 783                lcn = rl->lcn;
 784                if (unlikely(lcn == LCN_RL_NOT_MAPPED)) {
 785                        vcn = rl->vcn;
 786                        goto map_vcn;
 787                }
 788                /* If this run is not valid abort with an error. */
 789                if (unlikely(!rl->length || lcn < LCN_HOLE))
 790                        goto rl_err;
 791                /* Skip holes. */
 792                if (lcn == LCN_HOLE)
 793                        continue;
 794                block = lcn << vol->cluster_size_bits >> block_size_bits;
 795                len = rl->length;
 796                if (rl[1].vcn > end_vcn)
 797                        len = end_vcn - rl->vcn;
 798                end_block = (lcn + len) << vol->cluster_size_bits >>
 799                                block_size_bits;
 800                /* Iterate over the blocks in the run and empty them. */
 801                do {
 802                        struct buffer_head *bh;
 803
 804                        /* Obtain the buffer, possibly not uptodate. */
 805                        bh = sb_getblk(sb, block);
 806                        BUG_ON(!bh);
 807                        /* Setup buffer i/o submission. */
 808                        lock_buffer(bh);
 809                        bh->b_end_io = end_buffer_write_sync;
 810                        get_bh(bh);
 811                        /* Set the entire contents of the buffer to 0xff. */
 812                        memset(bh->b_data, -1, block_size);
 813                        if (!buffer_uptodate(bh))
 814                                set_buffer_uptodate(bh);
 815                        if (buffer_dirty(bh))
 816                                clear_buffer_dirty(bh);
 817                        /*
 818                         * Submit the buffer and wait for i/o to complete but
 819                         * only for the first buffer so we do not miss really
 820                         * serious i/o errors.  Once the first buffer has
 821                         * completed ignore errors afterwards as we can assume
 822                         * that if one buffer worked all of them will work.
 823                         */
 824                        submit_bh(WRITE, bh);
 825                        if (should_wait) {
 826                                should_wait = false;
 827                                wait_on_buffer(bh);
 828                                if (unlikely(!buffer_uptodate(bh)))
 829                                        goto io_err;
 830                        }
 831                        brelse(bh);
 832                } while (++block < end_block);
 833        } while ((++rl)->vcn < end_vcn);
 834        up_write(&log_ni->runlist.lock);
 835        /*
 836         * Zap the pages again just in case any got instantiated whilst we were
 837         * emptying the blocks by hand.  FIXME: We may not have completed
 838         * writing to all the buffer heads yet so this may happen too early.
 839         * We really should use a kernel thread to do the emptying
 840         * asynchronously and then we can also set the volume dirty and output
 841         * an error message if emptying should fail.
 842         */
 843        truncate_inode_pages(log_vi->i_mapping, 0);
 844        /* Set the flag so we do not have to do it again on remount. */
 845        NVolSetLogFileEmpty(vol);
 846        ntfs_debug("Done.");
 847        return true;
 848io_err:
 849        ntfs_error(sb, "Failed to write buffer.  Unmount and run chkdsk.");
 850        goto dirty_err;
 851rl_err:
 852        ntfs_error(sb, "Runlist is corrupt.  Unmount and run chkdsk.");
 853dirty_err:
 854        NVolSetErrors(vol);
 855        err = -EIO;
 856err:
 857        up_write(&log_ni->runlist.lock);
 858        ntfs_error(sb, "Failed to fill $LogFile with 0xff bytes (error %d).",
 859                        -err);
 860        return false;
 861}
 862
 863#endif /* NTFS_RW */
 864
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.