fs/ntfs/logfile.c

   1 /*
   2  * logfile.c - NTFS kernel journal handling. Part of the Linux-NTFS project.
   3  *
   4  * Copyright (c) 2002-2005 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
  30 #include "attrib.h"
  31 #include "aops.h"
  32 #include "debug.h"
  33 #include "logfile.h"
  34 #include "malloc.h"
  35 #include "volume.h"
  36 #include "ntfs.h"
  37
  38 /**
  39  * ntfs_check_restart_page_header - check the page header for consistency
  40  * @vi:         $LogFile inode to which the restart page header belongs
  41  * @rp:         restart page header to check
  42  * @pos:        position in @vi at which the restart page header resides
  43  *
  44  * Check the restart page header @rp for consistency and return 'true' if it is
  45  * consistent and 'false' otherwise.
  46  *
  47  * This function only needs NTFS_BLOCK_SIZE bytes in @rp, i.e. it does not
  48  * require the full restart page.
  49  */
  50 static bool ntfs_check_restart_page_header(struct inode *vi,
  51                 RESTART_PAGE_HEADER *rp, s64 pos)
  52 {
  53         u32 logfile_system_page_size, logfile_log_page_size;
  54         u16 ra_ofs, usa_count, usa_ofs, usa_end = 0;
  55         bool have_usa = true;
  56
  57         ntfs_debug("Entering.");
  58         /*
  59          * If the system or log page sizes are smaller than the ntfs block size
  60          * or either is not a power of 2 we cannot handle this log file.
  61          */
  62         logfile_system_page_size = le32_to_cpu(rp->system_page_size);
  63         logfile_log_page_size = le32_to_cpu(rp->log_page_size);
  64         if (logfile_system_page_size < NTFS_BLOCK_SIZE ||
  65                         logfile_log_page_size < NTFS_BLOCK_SIZE ||
  66                         logfile_system_page_size &
  67                         (logfile_system_page_size - 1) ||
  68                         logfile_log_page_size & (logfile_log_page_size - 1)) {
  69                 ntfs_error(vi->i_sb, "$LogFile uses unsupported page size.");
  70                 return false;
  71         }
  72         /*
  73          * We must be either at !pos (1st restart page) or at pos = system page
  74          * size (2nd restart page).
  75          */
  76         if (pos && pos != logfile_system_page_size) {
  77                 ntfs_error(vi->i_sb, "Found restart area in incorrect "
  78                                 "position in $LogFile.");
  79                 return false;
  80         }
  81         /* We only know how to handle version 1.1. */
  82         if (sle16_to_cpu(rp->major_ver) != 1 ||
  83                         sle16_to_cpu(rp->minor_ver) != 1) {
  84                 ntfs_error(vi->i_sb, "$LogFile version %i.%i is not "
  85                                 "supported.  (This driver supports version "
  86                                 "1.1 only.)", (int)sle16_to_cpu(rp->major_ver),
  87                                 (int)sle16_to_cpu(rp->minor_ver));
  88                 return false;
  89         }
  90         /*
  91          * If chkdsk has been run the restart page may not be protected by an
  92          * update sequence array.
  93          */
  94         if (ntfs_is_chkd_record(rp->magic) && !le16_to_cpu(rp->usa_count)) {
  95                 have_usa = false;
  96                 goto skip_usa_checks;
  97         }
  98         /* Verify the size of the update sequence array. */
  99         usa_count = 1 + (logfile_system_page_size >> NTFS_BLOCK_SIZE_BITS);
 100         if (usa_count != le16_to_cpu(rp->usa_count)) {
 101                 ntfs_error(vi->i_sb, "$LogFile restart page specifies "
 102                                 "inconsistent update sequence array count.");
 103                 return false;
 104         }
 105         /* Verify the position of the update sequence array. */
 106         usa_ofs = le16_to_cpu(rp->usa_ofs);
 107         usa_end = usa_ofs + usa_count * sizeof(u16);
 108         if (usa_ofs < sizeof(RESTART_PAGE_HEADER) ||
 109                         usa_end > NTFS_BLOCK_SIZE - sizeof(u16)) {
 110                 ntfs_error(vi->i_sb, "$LogFile restart page specifies "
 111                                 "inconsistent update sequence array offset.");
 112                 return false;
 113         }
 114 skip_usa_checks:
 115         /*
 116          * Verify the position of the restart area.  It must be:
 117          *      - aligned to 8-byte boundary,
 118          *      - after the update sequence array, and
 119          *      - within the system page size.
 120          */
 121         ra_ofs = le16_to_cpu(rp->restart_area_offset);
 122         if (ra_ofs & 7 || (have_usa ? ra_ofs < usa_end :
 123                         ra_ofs < sizeof(RESTART_PAGE_HEADER)) ||
 124                         ra_ofs > logfile_system_page_size) {
 125                 ntfs_error(vi->i_sb, "$LogFile restart page specifies "
 126                                 "inconsistent restart area offset.");
 127                 return false;
 128         }
 129         /*
 130          * Only restart pages modified by chkdsk are allowed to have chkdsk_lsn
 131          * set.
 132          */
 133         if (!ntfs_is_chkd_record(rp->magic) && sle64_to_cpu(rp->chkdsk_lsn)) {
 134                 ntfs_error(vi->i_sb, "$LogFile restart page is not modified "
 135                                 "by chkdsk but a chkdsk LSN is specified.");
 136                 return false;
 137         }
 138         ntfs_debug("Done.");
 139         return true;
 140 }
 141
 142 /**
 143  * ntfs_check_restart_area - check the restart area for consistency
 144  * @vi:         $LogFile inode to which the restart page belongs
 145  * @rp:         restart page whose restart area to check
 146  *
 147  * Check the restart area of the restart page @rp for consistency and return
 148  * 'true' if it is consistent and 'false' otherwise.
 149  *
 150  * This function assumes that the restart page header has already been
 151  * consistency checked.
 152  *
 153  * This function only needs NTFS_BLOCK_SIZE bytes in @rp, i.e. it does not
 154  * require the full restart page.
 155  */
 156 static bool ntfs_check_restart_area(struct inode *vi, RESTART_PAGE_HEADER *rp)
 157 {
 158         u64 file_size;
 159         RESTART_AREA *ra;
 160         u16 ra_ofs, ra_len, ca_ofs;
 161         u8 fs_bits;
 162
 163         ntfs_debug("Entering.");
 164         ra_ofs = le16_to_cpu(rp->restart_area_offset);
 165         ra = (RESTART_AREA*)((u8*)rp + ra_ofs);
 166         /*
 167          * Everything before ra->file_size must be before the first word
 168          * protected by an update sequence number.  This ensures that it is
 169          * safe to access ra->client_array_offset.
 170          */
 171         if (ra_ofs + offsetof(RESTART_AREA, file_size) >
 172                         NTFS_BLOCK_SIZE - sizeof(u16)) {
 173                 ntfs_error(vi->i_sb, "$LogFile restart area specifies "
 174                                 "inconsistent file offset.");
 175                 return false;
 176         }
 177         /*
 178          * Now that we can access ra->client_array_offset, make sure everything
 179          * up to the log client array is before the first word protected by an
 180          * update sequence number.  This ensures we can access all of the
 181          * restart area elements safely.  Also, the client array offset must be
 182          * aligned to an 8-byte boundary.
 183          */
 184         ca_ofs = le16_to_cpu(ra->client_array_offset);
 185         if (((ca_ofs + 7) & ~7) != ca_ofs ||
 186                         ra_ofs + ca_ofs > NTFS_BLOCK_SIZE - sizeof(u16)) {
 187                 ntfs_error(vi->i_sb, "$LogFile restart area specifies "
 188                                 "inconsistent client array offset.");
 189                 return false;
 190         }
 191         /*
 192          * The restart area must end within the system page size both when
 193          * calculated manually and as specified by ra->restart_area_length.
 194          * Also, the calculated length must not exceed the specified length.
 195          */
 196         ra_len = ca_ofs + le16_to_cpu(ra->log_clients) *
 197                         sizeof(LOG_CLIENT_RECORD);
 198         if (ra_ofs + ra_len > le32_to_cpu(rp->system_page_size) ||
 199                         ra_ofs + le16_to_cpu(ra->restart_area_length) >
 200                         le32_to_cpu(rp->system_page_size) ||
 201                         ra_len > le16_to_cpu(ra->restart_area_length)) {
 202                 ntfs_error(vi->i_sb, "$LogFile restart area is out of bounds "
 203                                 "of the system page size specified by the "
 204                                 "restart page header and/or the specified "
 205                                 "restart area length is inconsistent.");
 206                 return false;
 207         }
 208         /*
 209          * The ra->client_free_list and ra->client_in_use_list must be either
 210          * LOGFILE_NO_CLIENT or less than ra->log_clients or they are
 211          * overflowing the client array.
 212          */
 213         if ((ra->client_free_list != LOGFILE_NO_CLIENT &&
 214                         le16_to_cpu(ra->client_free_list) >=
 215                         le16_to_cpu(ra->log_clients)) ||
 216                         (ra->client_in_use_list != LOGFILE_NO_CLIENT &&
 217                         le16_to_cpu(ra->client_in_use_list) >=
 218                         le16_to_cpu(ra->log_clients))) {
 219                 ntfs_error(vi->i_sb, "$LogFile restart area specifies "
 220                                 "overflowing client free and/or in use lists.");
 221                 return false;
 222         }
 223         /*
 224          * Check ra->seq_number_bits against ra->file_size for consistency.
 225          * We cannot just use ffs() because the file size is not a power of 2.
 226          */
 227         file_size = (u64)sle64_to_cpu(ra->file_size);
 228         fs_bits = 0;
 229         while (file_size) {
 230                 file_size >>= 1;
 231                 fs_bits++;
 232         }
 233         if (le32_to_cpu(ra->seq_number_bits) != 67 - fs_bits) {
 234                 ntfs_error(vi->i_sb, "$LogFile restart area specifies "
 235                                 "inconsistent sequence number bits.");
 236                 return false;
 237         }
 238         /* The log record header length must be a multiple of 8. */
 239         if (((le16_to_cpu(ra->log_record_header_length) + 7) & ~7) !=
 240                         le16_to_cpu(ra->log_record_header_length)) {
 241                 ntfs_error(vi->i_sb, "$LogFile restart area specifies "
 242                                 "inconsistent log record header length.");
 243                 return false;
 244         }
 245         /* Dito for the log page data offset. */
 246         if (((le16_to_cpu(ra->log_page_data_offset) + 7) & ~7) !=
 247                         le16_to_cpu(ra->log_page_data_offset)) {
 248                 ntfs_error(vi->i_sb, "$LogFile restart area specifies "
 249                                 "inconsistent log page data offset.");
 250                 return false;
 251         }
 252         ntfs_debug("Done.");
 253         return true;
 254 }
 255
 256 /**
 257  * ntfs_check_log_client_array - check the log client array for consistency
 258  * @vi:         $LogFile inode to which the restart page belongs
 259  * @rp:         restart page whose log client array to check
 260  *
 261  * Check the log client array of the restart page @rp for consistency and
 262  * return 'true' if it is consistent and 'false' otherwise.
 263  *
 264  * This function assumes that the restart page header and the restart area have
 265  * already been consistency checked.
 266  *
 267  * Unlike ntfs_check_restart_page_header() and ntfs_check_restart_area(), this
 268  * function needs @rp->system_page_size bytes in @rp, i.e. it requires the full
 269  * restart page and the page must be multi sector transfer deprotected.
 270  */
 271 static bool ntfs_check_log_client_array(struct inode *vi,
 272                 RESTART_PAGE_HEADER *rp)
 273 {
 274         RESTART_AREA *ra;
 275         LOG_CLIENT_RECORD *ca, *cr;
 276         u16 nr_clients, idx;
 277         bool in_free_list, idx_is_first;
 278
 279         ntfs_debug("Entering.");
 280         ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
 281         ca = (LOG_CLIENT_RECORD*)((u8*)ra +
 282                         le16_to_cpu(ra->client_array_offset));
 283         /*
 284          * Check the ra->client_free_list first and then check the
 285          * ra->client_in_use_list.  Check each of the log client records in
 286          * each of the lists and check that the array does not overflow the
 287          * ra->log_clients value.  Also keep track of the number of records
 288          * visited as there cannot be more than ra->log_clients records and
 289          * that way we detect eventual loops in within a list.
 290          */
 291         nr_clients = le16_to_cpu(ra->log_clients);
 292         idx = le16_to_cpu(ra->client_free_list);
 293         in_free_list = true;
 294 check_list:
 295         for (idx_is_first = true; idx != LOGFILE_NO_CLIENT_CPU; nr_clients--,
 296                         idx = le16_to_cpu(cr->next_client)) {
 297                 if (!nr_clients || idx >= le16_to_cpu(ra->log_clients))
 298                         goto err_out;
 299                 /* Set @cr to the current log client record. */
 300                 cr = ca + idx;
 301                 /* The first log client record must not have a prev_client. */
 302                 if (idx_is_first) {
 303                         if (cr->prev_client != LOGFILE_NO_CLIENT)
 304                                 goto err_out;
 305                         idx_is_first = false;
 306                 }
 307         }
 308         /* Switch to and check the in use list if we just did the free list. */
 309         if (in_free_list) {
 310                 in_free_list = false;
 311                 idx = le16_to_cpu(ra->client_in_use_list);
 312                 goto check_list;
 313         }
 314         ntfs_debug("Done.");
 315         return true;
 316 err_out:
 317         ntfs_error(vi->i_sb, "$LogFile log client array is corrupt.");
 318         return false;
 319 }
 320
 321 /**
 322  * ntfs_check_and_load_restart_page - check the restart page for consistency
 323  * @vi:         $LogFile inode to which the restart page belongs
 324  * @rp:         restart page to check
 325  * @pos:        position in @vi at which the restart page resides
 326  * @wrp:        [OUT] copy of the multi sector transfer deprotected restart page
 327  * @lsn:        [OUT] set to the current logfile lsn on success
 328  *
 329  * Check the restart page @rp for consistency and return 0 if it is consistent
 330  * and -errno otherwise.  The restart page may have been modified by chkdsk in
 331  * which case its magic is CHKD instead of RSTR.
 332  *
 333  * This function only needs NTFS_BLOCK_SIZE bytes in @rp, i.e. it does not
 334  * require the full restart page.
 335  *
 336  * If @wrp is not NULL, on success, *@wrp will point to a buffer containing a
 337  * copy of the complete multi sector transfer deprotected page.  On failure,
 338  * *@wrp is undefined.
 339  *
 340  * Simillarly, if @lsn is not NULL, on succes *@lsn will be set to the current
 341  * logfile lsn according to this restart page.  On failure, *@lsn is undefined.
 342  *
 343  * The following error codes are defined:
 344  *      -EINVAL - The restart page is inconsistent.
 345  *      -ENOMEM - Not enough memory to load the restart page.
 346  *      -EIO    - Failed to reading from $LogFile.
 347  */
 348 static int ntfs_check_and_load_restart_page(struct inode *vi,
 349                 RESTART_PAGE_HEADER *rp, s64 pos, RESTART_PAGE_HEADER **wrp,
 350                 LSN *lsn)
 351 {
 352         RESTART_AREA *ra;
 353         RESTART_PAGE_HEADER *trp;
 354         int size, err;
 355
 356         ntfs_debug("Entering.");
 357         /* Check the restart page header for consistency. */
 358         if (!ntfs_check_restart_page_header(vi, rp, pos)) {
 359                 /* Error output already done inside the function. */
 360                 return -EINVAL;
 361         }
 362         /* Check the restart area for consistency. */
 363         if (!ntfs_check_restart_area(vi, rp)) {
 364                 /* Error output already done inside the function. */
 365                 return -EINVAL;
 366         }
 367         ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
 368         /*
 369          * Allocate a buffer to store the whole restart page so we can multi
 370          * sector transfer deprotect it.
 371          */
 372         trp = ntfs_malloc_nofs(le32_to_cpu(rp->system_page_size));
 373         if (!trp) {
 374                 ntfs_error(vi->i_sb, "Failed to allocate memory for $LogFile "
 375                                 "restart page buffer.");
 376                 return -ENOMEM;
 377         }
 378         /*
 379          * Read the whole of the restart page into the buffer.  If it fits
 380          * completely inside @rp, just copy it from there.  Otherwise map all
 381          * the required pages and copy the data from them.
 382          */
 383         size = PAGE_CACHE_SIZE - (pos & ~PAGE_CACHE_MASK);
 384         if (size >= le32_to_cpu(rp->system_page_size)) {
 385                 memcpy(trp, rp, le32_to_cpu(rp->system_page_size));
 386         } else {
 387                 pgoff_t idx;
 388                 struct page *page;
 389                 int have_read, to_read;
 390
 391                 /* First copy what we already have in @rp. */
 392                 memcpy(trp, rp, size);
 393                 /* Copy the remaining data one page at a time. */
 394                 have_read = size;
 395                 to_read = le32_to_cpu(rp->system_page_size) - size;
 396                 idx = (pos + size) >> PAGE_CACHE_SHIFT;
 397                 BUG_ON((pos + size) & ~PAGE_CACHE_MASK);
 398                 do {
 399                         page = ntfs_map_page(vi->i_mapping, idx);
 400                         if (IS_ERR(page)) {
 401                                 ntfs_error(vi->i_sb, "Error mapping $LogFile "
 402                                                 "page (index %lu).", idx);
 403                                 err = PTR_ERR(page);
 404                                 if (err != -EIO && err != -ENOMEM)
 405                                         err = -EIO;
 406                                 goto err_out;
 407                         }
 408                         size = min_t(int, to_read, PAGE_CACHE_SIZE);
 409                         memcpy((u8*)trp + have_read, page_address(page), size);
 410                         ntfs_unmap_page(page);
 411                         have_read += size;
 412                         to_read -= size;
 413                         idx++;
 414                 } while (to_read > 0);
 415         }
 416         /*
 417          * Perform the multi sector transfer deprotection on the buffer if the
 418          * restart page is protected.
 419          */
 420         if ((!ntfs_is_chkd_record(trp->magic) || le16_to_cpu(trp->usa_count))
 421                         && post_read_mst_fixup((NTFS_RECORD*)trp,
 422                         le32_to_cpu(rp->system_page_size))) {
 423                 /*
 424                  * A multi sector tranfer error was detected.  We only need to
 425                  * abort if the restart page contents exceed the multi sector
 426                  * transfer fixup of the first sector.
 427                  */
 428                 if (le16_to_cpu(rp->restart_area_offset) +
 429                                 le16_to_cpu(ra->restart_area_length) >
 430                                 NTFS_BLOCK_SIZE - sizeof(u16)) {
 431                         ntfs_error(vi->i_sb, "Multi sector transfer error "
 432                                         "detected in $LogFile restart page.");
 433                         err = -EINVAL;
 434                         goto err_out;
 435                 }
 436         }
 437         /*
 438          * If the restart page is modified by chkdsk or there are no active
 439          * logfile clients, the logfile is consistent.  Otherwise, need to
 440          * check the log client records for consistency, too.
 441          */
 442         err = 0;
 443         if (ntfs_is_rstr_record(rp->magic) &&
 444                         ra->client_in_use_list != LOGFILE_NO_CLIENT) {
 445                 if (!ntfs_check_log_client_array(vi, trp)) {
 446                         err = -EINVAL;
 447                         goto err_out;
 448                 }
 449         }
 450         if (lsn) {
 451                 if (ntfs_is_rstr_record(rp->magic))
 452                         *lsn = sle64_to_cpu(ra->current_lsn);
 453                 else /* if (ntfs_is_chkd_record(rp->magic)) */
 454                         *lsn = sle64_to_cpu(rp->chkdsk_lsn);
 455         }
 456         ntfs_debug("Done.");
 457         if (wrp)
 458                 *wrp = trp;
 459         else {
 460 err_out:
 461                 ntfs_free(trp);
 462         }
 463         return err;
 464 }
 465
 466 /**
 467  * ntfs_check_logfile - check the journal for consistency
 468  * @log_vi:     struct inode of loaded journal $LogFile to check
 469  * @rp:         [OUT] on success this is a copy of the current restart page
 470  *
 471  * Check the $LogFile journal for consistency and return 'true' if it is
 472  * consistent and 'false' if not.  On success, the current restart page is
 473  * returned in *@rp.  Caller must call ntfs_free(*@rp) when finished with it.
 474  *
 475  * At present we only check the two restart pages and ignore the log record
 476  * pages.
 477  *
 478  * Note that the MstProtected flag is not set on the $LogFile inode and hence
 479  * when reading pages they are not deprotected.  This is because we do not know
 480  * if the $LogFile was created on a system with a different page size to ours
 481  * yet and mst deprotection would fail if our page size is smaller.
 482  */
 483 bool ntfs_check_logfile(struct inode *log_vi, RESTART_PAGE_HEADER **rp)
 484 {
 485         s64 size, pos;
 486         LSN rstr1_lsn, rstr2_lsn;
 487         ntfs_volume *vol = NTFS_SB(log_vi->i_sb);
 488         struct address_space *mapping = log_vi->i_mapping;
 489         struct page *page = NULL;
 490         u8 *kaddr = NULL;
 491         RESTART_PAGE_HEADER *rstr1_ph = NULL;
 492         RESTART_PAGE_HEADER *rstr2_ph = NULL;
 493         int log_page_size, log_page_mask, err;
 494         bool logfile_is_empty = true;
 495         u8 log_page_bits;
 496
 497         ntfs_debug("Entering.");
 498         /* An empty $LogFile must have been clean before it got emptied. */
 499         if (NVolLogFileEmpty(vol))
 500                 goto is_empty;
 501         size = i_size_read(log_vi);
 502         /* Make sure the file doesn't exceed the maximum allowed size. */
 503         if (size > MaxLogFileSize)
 504                 size = MaxLogFileSize;
 505         /*
 506          * Truncate size to a multiple of the page cache size or the default
 507          * log page size if the page cache size is between the default log page
 508          * log page size if the page cache size is between the default log page
 509          * size and twice that.
 510          */
 511         if (PAGE_CACHE_SIZE >= DefaultLogPageSize && PAGE_CACHE_SIZE <=
 512                         DefaultLogPageSize * 2)
 513                 log_page_size = DefaultLogPageSize;
 514         else
 515                 log_page_size = PAGE_CACHE_SIZE;
 516         log_page_mask = log_page_size - 1;
 517         /*
 518          * Use ntfs_ffs() instead of ffs() to enable the compiler to
 519          * optimize log_page_size and log_page_bits into constants.
 520          */
 521         log_page_bits = ntfs_ffs(log_page_size) - 1;
 522         size &= ~(s64)(log_page_size - 1);
 523         /*
 524          * Ensure the log file is big enough to store at least the two restart
 525          * pages and the minimum number of log record pages.
 526          */
 527         if (size < log_page_size * 2 || (size - log_page_size * 2) >>
 528                         log_page_bits < MinLogRecordPages) {
 529                 ntfs_error(vol->sb, "$LogFile is too small.");
 530                 return false;
 531         }
 532         /*
 533          * Read through the file looking for a restart page.  Since the restart
 534          * page header is at the beginning of a page we only need to search at
 535          * what could be the beginning of a page (for each page size) rather
 536          * than scanning the whole file byte by byte.  If all potential places
 537          * contain empty and uninitialzed records, the log file can be assumed
 538          * to be empty.
 539          */
 540         for (pos = 0; pos < size; pos <<= 1) {
 541                 pgoff_t idx = pos >> PAGE_CACHE_SHIFT;
 542                 if (!page || page->index != idx) {
 543                         if (page)
 544                                 ntfs_unmap_page(page);
 545                         page = ntfs_map_page(mapping, idx);
 546                         if (IS_ERR(page)) {
 547                                 ntfs_error(vol->sb, "Error mapping $LogFile "
 548                                                 "page (index %lu).", idx);
 549                                 goto err_out;
 550                         }
 551                 }
 552                 kaddr = (u8*)page_address(page) + (pos & ~PAGE_CACHE_MASK);
 553                 /*
 554                  * A non-empty block means the logfile is not empty while an
 555                  * empty block after a non-empty block has been encountered
 556                  * means we are done.
 557                  */
 558                 if (!ntfs_is_empty_recordp((le32*)kaddr))
 559                         logfile_is_empty = false;
 560                 else if (!logfile_is_empty)
 561                         break;
 562                 /*
 563                  * A log record page means there cannot be a restart page after
 564                  * this so no need to continue searching.
 565                  */
 566                 if (ntfs_is_rcrd_recordp((le32*)kaddr))
 567                         break;
 568                 /* If not a (modified by chkdsk) restart page, continue. */
 569                 if (!ntfs_is_rstr_recordp((le32*)kaddr) &&
 570                                 !ntfs_is_chkd_recordp((le32*)kaddr)) {
 571                         if (!pos)
 572                                 pos = NTFS_BLOCK_SIZE >> 1;
 573                         continue;
 574                 }
 575                 /*
 576                  * Check the (modified by chkdsk) restart page for consistency
 577                  * and get a copy of the complete multi sector transfer
 578                  * deprotected restart page.
 579                  */
 580                 err = ntfs_check_and_load_restart_page(log_vi,
 581                                 (RESTART_PAGE_HEADER*)kaddr, pos,
 582                                 !rstr1_ph ? &rstr1_ph : &rstr2_ph,
 583                                 !rstr1_ph ? &rstr1_lsn : &rstr2_lsn);
 584                 if (!err) {
 585                         /*
 586                          * If we have now found the first (modified by chkdsk)
 587                          * restart page, continue looking for the second one.
 588                          */
 589                         if (!pos) {
 590                                 pos = NTFS_BLOCK_SIZE >> 1;
 591                                 continue;
 592                         }
 593                         /*
 594                          * We have now found the second (modified by chkdsk)
 595                          * restart page, so we can stop looking.
 596                          */
 597                         break;
 598                 }
 599                 /*
 600                  * Error output already done inside the function.  Note, we do
 601                  * not abort if the restart page was invalid as we might still
 602                  * find a valid one further in the file.
 603                  */
 604                 if (err != -EINVAL) {
 605                         ntfs_unmap_page(page);
 606                         goto err_out;
 607                 }
 608                 /* Continue looking. */
 609                 if (!pos)
 610                         pos = NTFS_BLOCK_SIZE >> 1;
 611         }
 612         if (page)
 613                 ntfs_unmap_page(page);
 614         if (logfile_is_empty) {
 615                 NVolSetLogFileEmpty(vol);
 616 is_empty:
 617                 ntfs_debug("Done.  ($LogFile is empty.)");
 618                 return true;
 619         }
 620         if (!rstr1_ph) {
 621                 BUG_ON(rstr2_ph);
 622                 ntfs_error(vol->sb, "Did not find any restart pages in "
 623                                 "$LogFile and it was not empty.");
 624                 return false;
 625         }
 626         /* If both restart pages were found, use the more recent one. */
 627         if (rstr2_ph) {
 628                 /*
 629                  * If the second restart area is more recent, switch to it.
 630                  * Otherwise just throw it away.
 631                  */
 632                 if (rstr2_lsn > rstr1_lsn) {
 633                         ntfs_debug("Using second restart page as it is more "
 634                                         "recent.");
 635                         ntfs_free(rstr1_ph);
 636                         rstr1_ph = rstr2_ph;
 637                         /* rstr1_lsn = rstr2_lsn; */
 638                 } else {
 639                         ntfs_debug("Using first restart page as it is more "
 640                                         "recent.");
 641                         ntfs_free(rstr2_ph);
 642                 }
 643                 rstr2_ph = NULL;
 644         }
 645         /* All consistency checks passed. */
 646         if (rp)
 647                 *rp = rstr1_ph;
 648         else
 649                 ntfs_free(rstr1_ph);
 650         ntfs_debug("Done.");
 651         return true;
 652 err_out:
 653         if (rstr1_ph)
 654                 ntfs_free(rstr1_ph);
 655         return false;
 656 }
 657
 658 /**
 659  * ntfs_is_logfile_clean - check in the journal if the volume is clean
 660  * @log_vi:     struct inode of loaded journal $LogFile to check
 661  * @rp:         copy of the current restart page
 662  *
 663  * Analyze the $LogFile journal and return 'true' if it indicates the volume was
 664  * shutdown cleanly and 'false' if not.
 665  *
 666  * At present we only look at the two restart pages and ignore the log record
 667  * pages.  This is a little bit crude in that there will be a very small number
 668  * of cases where we think that a volume is dirty when in fact it is clean.
 669  * This should only affect volumes that have not been shutdown cleanly but did
 670  * not have any pending, non-check-pointed i/o, i.e. they were completely idle
 671  * at least for the five seconds preceeding the unclean shutdown.
 672  *
 673  * This function assumes that the $LogFile journal has already been consistency
 674  * checked by a call to ntfs_check_logfile() and in particular if the $LogFile
 675  * is empty this function requires that NVolLogFileEmpty() is true otherwise an
 676  * empty volume will be reported as dirty.
 677  */
 678 bool ntfs_is_logfile_clean(struct inode *log_vi, const RESTART_PAGE_HEADER *rp)
 679 {
 680         ntfs_volume *vol = NTFS_SB(log_vi->i_sb);
 681         RESTART_AREA *ra;
 682
 683         ntfs_debug("Entering.");
 684         /* An empty $LogFile must have been clean before it got emptied. */
 685         if (NVolLogFileEmpty(vol)) {
 686                 ntfs_debug("Done.  ($LogFile is empty.)");
 687                 return true;
 688         }
 689         BUG_ON(!rp);
 690         if (!ntfs_is_rstr_record(rp->magic) &&
 691                         !ntfs_is_chkd_record(rp->magic)) {
 692                 ntfs_error(vol->sb, "Restart page buffer is invalid.  This is "
 693                                 "probably a bug in that the $LogFile should "
 694                                 "have been consistency checked before calling "
 695                                 "this function.");
 696                 return false;
 697         }
 698         ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
 699         /*
 700          * If the $LogFile has active clients, i.e. it is open, and we do not
 701          * have the RESTART_VOLUME_IS_CLEAN bit set in the restart area flags,
 702          * we assume there was an unclean shutdown.
 703          */
 704         if (ra->client_in_use_list != LOGFILE_NO_CLIENT &&
 705                         !(ra->flags & RESTART_VOLUME_IS_CLEAN)) {
 706                 ntfs_debug("Done.  $LogFile indicates a dirty shutdown.");
 707                 return false;
 708         }
 709         /* $LogFile indicates a clean shutdown. */
 710         ntfs_debug("Done.  $LogFile indicates a clean shutdown.");
 711         return true;
 712 }
 713
 714 /**
 715  * ntfs_empty_logfile - empty the contents of the $LogFile journal
 716  * @log_vi:     struct inode of loaded journal $LogFile to empty
 717  *
 718  * Empty the contents of the $LogFile journal @log_vi and return 'true' on
 719  * success and 'false' on error.
 720  *
 721  * This function assumes that the $LogFile journal has already been consistency
 722  * checked by a call to ntfs_check_logfile() and that ntfs_is_logfile_clean()
 723  * has been used to ensure that the $LogFile is clean.
 724  */
 725 bool ntfs_empty_logfile(struct inode *log_vi)
 726 {
 727         ntfs_volume *vol = NTFS_SB(log_vi->i_sb);
 728
 729         ntfs_debug("Entering.");
 730         if (!NVolLogFileEmpty(vol)) {
 731                 int err;
 732
 733                 err = ntfs_attr_set(NTFS_I(log_vi), 0, i_size_read(log_vi),
 734                                 0xff);
 735                 if (unlikely(err)) {
 736                         ntfs_error(vol->sb, "Failed to fill $LogFile with "
 737                                         "0xff bytes (error code %i).", err);
 738                         return false;
 739                 }
 740                 /* Set the flag so we do not have to do it again on remount. */
 741                 NVolSetLogFileEmpty(vol);
 742         }
 743         ntfs_debug("Done.");
 744         return true;
 745 }
 746
 747 #endif /* NTFS_RW */