Root/fs/ntfs/logfile.c

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

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