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  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * logfile.c - NTFS kernel journal handling. Part of the Linux-NTFS project.
  4 *
  5 * Copyright (c) 2002-2007 Anton Altaparmakov
  6 */
  7
  8#ifdef NTFS_RW
  9
 10#include <linux/types.h>
 11#include <linux/fs.h>
 12#include <linux/highmem.h>
 13#include <linux/buffer_head.h>
 14#include <linux/bitops.h>
 15#include <linux/log2.h>
 16#include <linux/bio.h>
 17
 18#include "attrib.h"
 19#include "aops.h"
 20#include "debug.h"
 21#include "logfile.h"
 22#include "malloc.h"
 23#include "volume.h"
 24#include "ntfs.h"
 25
 26/**
 27 * ntfs_check_restart_page_header - check the page header for consistency
 28 * @vi:		$LogFile inode to which the restart page header belongs
 29 * @rp:		restart page header to check
 30 * @pos:	position in @vi at which the restart page header resides
 31 *
 32 * Check the restart page header @rp for consistency and return 'true' if it is
 33 * consistent and 'false' otherwise.
 34 *
 35 * This function only needs NTFS_BLOCK_SIZE bytes in @rp, i.e. it does not
 36 * require the full restart page.
 37 */
 38static bool ntfs_check_restart_page_header(struct inode *vi,
 39		RESTART_PAGE_HEADER *rp, s64 pos)
 40{
 41	u32 logfile_system_page_size, logfile_log_page_size;
 42	u16 ra_ofs, usa_count, usa_ofs, usa_end = 0;
 43	bool have_usa = true;
 44
 45	ntfs_debug("Entering.");
 46	/*
 47	 * If the system or log page sizes are smaller than the ntfs block size
 48	 * or either is not a power of 2 we cannot handle this log file.
 49	 */
 50	logfile_system_page_size = le32_to_cpu(rp->system_page_size);
 51	logfile_log_page_size = le32_to_cpu(rp->log_page_size);
 52	if (logfile_system_page_size < NTFS_BLOCK_SIZE ||
 53			logfile_log_page_size < NTFS_BLOCK_SIZE ||
 54			logfile_system_page_size &
 55			(logfile_system_page_size - 1) ||
 56			!is_power_of_2(logfile_log_page_size)) {
 57		ntfs_error(vi->i_sb, "$LogFile uses unsupported page size.");
 58		return false;
 59	}
 60	/*
 61	 * We must be either at !pos (1st restart page) or at pos = system page
 62	 * size (2nd restart page).
 63	 */
 64	if (pos && pos != logfile_system_page_size) {
 65		ntfs_error(vi->i_sb, "Found restart area in incorrect "
 66				"position in $LogFile.");
 67		return false;
 68	}
 69	/* We only know how to handle version 1.1. */
 70	if (sle16_to_cpu(rp->major_ver) != 1 ||
 71			sle16_to_cpu(rp->minor_ver) != 1) {
 72		ntfs_error(vi->i_sb, "$LogFile version %i.%i is not "
 73				"supported.  (This driver supports version "
 74				"1.1 only.)", (int)sle16_to_cpu(rp->major_ver),
 75				(int)sle16_to_cpu(rp->minor_ver));
 76		return false;
 77	}
 78	/*
 79	 * If chkdsk has been run the restart page may not be protected by an
 80	 * update sequence array.
 81	 */
 82	if (ntfs_is_chkd_record(rp->magic) && !le16_to_cpu(rp->usa_count)) {
 83		have_usa = false;
 84		goto skip_usa_checks;
 85	}
 86	/* Verify the size of the update sequence array. */
 87	usa_count = 1 + (logfile_system_page_size >> NTFS_BLOCK_SIZE_BITS);
 88	if (usa_count != le16_to_cpu(rp->usa_count)) {
 89		ntfs_error(vi->i_sb, "$LogFile restart page specifies "
 90				"inconsistent update sequence array count.");
 91		return false;
 92	}
 93	/* Verify the position of the update sequence array. */
 94	usa_ofs = le16_to_cpu(rp->usa_ofs);
 95	usa_end = usa_ofs + usa_count * sizeof(u16);
 96	if (usa_ofs < sizeof(RESTART_PAGE_HEADER) ||
 97			usa_end > NTFS_BLOCK_SIZE - sizeof(u16)) {
 98		ntfs_error(vi->i_sb, "$LogFile restart page specifies "
 99				"inconsistent update sequence array offset.");
100		return false;
101	}
102skip_usa_checks:
103	/*
104	 * Verify the position of the restart area.  It must be:
105	 *	- aligned to 8-byte boundary,
106	 *	- after the update sequence array, and
107	 *	- within the system page size.
108	 */
109	ra_ofs = le16_to_cpu(rp->restart_area_offset);
110	if (ra_ofs & 7 || (have_usa ? ra_ofs < usa_end :
111			ra_ofs < sizeof(RESTART_PAGE_HEADER)) ||
112			ra_ofs > logfile_system_page_size) {
113		ntfs_error(vi->i_sb, "$LogFile restart page specifies "
114				"inconsistent restart area offset.");
115		return false;
116	}
117	/*
118	 * Only restart pages modified by chkdsk are allowed to have chkdsk_lsn
119	 * set.
120	 */
121	if (!ntfs_is_chkd_record(rp->magic) && sle64_to_cpu(rp->chkdsk_lsn)) {
122		ntfs_error(vi->i_sb, "$LogFile restart page is not modified "
123				"by chkdsk but a chkdsk LSN is specified.");
124		return false;
125	}
126	ntfs_debug("Done.");
127	return true;
128}
129
130/**
131 * ntfs_check_restart_area - check the restart area for consistency
132 * @vi:		$LogFile inode to which the restart page belongs
133 * @rp:		restart page whose restart area to check
134 *
135 * Check the restart area of the restart page @rp for consistency and return
136 * 'true' if it is consistent and 'false' otherwise.
137 *
138 * This function assumes that the restart page header has already been
139 * consistency checked.
140 *
141 * This function only needs NTFS_BLOCK_SIZE bytes in @rp, i.e. it does not
142 * require the full restart page.
143 */
144static bool ntfs_check_restart_area(struct inode *vi, RESTART_PAGE_HEADER *rp)
145{
146	u64 file_size;
147	RESTART_AREA *ra;
148	u16 ra_ofs, ra_len, ca_ofs;
149	u8 fs_bits;
150
151	ntfs_debug("Entering.");
152	ra_ofs = le16_to_cpu(rp->restart_area_offset);
153	ra = (RESTART_AREA*)((u8*)rp + ra_ofs);
154	/*
155	 * Everything before ra->file_size must be before the first word
156	 * protected by an update sequence number.  This ensures that it is
157	 * safe to access ra->client_array_offset.
158	 */
159	if (ra_ofs + offsetof(RESTART_AREA, file_size) >
160			NTFS_BLOCK_SIZE - sizeof(u16)) {
161		ntfs_error(vi->i_sb, "$LogFile restart area specifies "
162				"inconsistent file offset.");
163		return false;
164	}
165	/*
166	 * Now that we can access ra->client_array_offset, make sure everything
167	 * up to the log client array is before the first word protected by an
168	 * update sequence number.  This ensures we can access all of the
169	 * restart area elements safely.  Also, the client array offset must be
170	 * aligned to an 8-byte boundary.
171	 */
172	ca_ofs = le16_to_cpu(ra->client_array_offset);
173	if (((ca_ofs + 7) & ~7) != ca_ofs ||
174			ra_ofs + ca_ofs > NTFS_BLOCK_SIZE - sizeof(u16)) {
175		ntfs_error(vi->i_sb, "$LogFile restart area specifies "
176				"inconsistent client array offset.");
177		return false;
178	}
179	/*
180	 * The restart area must end within the system page size both when
181	 * calculated manually and as specified by ra->restart_area_length.
182	 * Also, the calculated length must not exceed the specified length.
183	 */
184	ra_len = ca_ofs + le16_to_cpu(ra->log_clients) *
185			sizeof(LOG_CLIENT_RECORD);
186	if (ra_ofs + ra_len > le32_to_cpu(rp->system_page_size) ||
187			ra_ofs + le16_to_cpu(ra->restart_area_length) >
188			le32_to_cpu(rp->system_page_size) ||
189			ra_len > le16_to_cpu(ra->restart_area_length)) {
190		ntfs_error(vi->i_sb, "$LogFile restart area is out of bounds "
191				"of the system page size specified by the "
192				"restart page header and/or the specified "
193				"restart area length is inconsistent.");
194		return false;
195	}
196	/*
197	 * The ra->client_free_list and ra->client_in_use_list must be either
198	 * LOGFILE_NO_CLIENT or less than ra->log_clients or they are
199	 * overflowing the client array.
200	 */
201	if ((ra->client_free_list != LOGFILE_NO_CLIENT &&
202			le16_to_cpu(ra->client_free_list) >=
203			le16_to_cpu(ra->log_clients)) ||
204			(ra->client_in_use_list != LOGFILE_NO_CLIENT &&
205			le16_to_cpu(ra->client_in_use_list) >=
206			le16_to_cpu(ra->log_clients))) {
207		ntfs_error(vi->i_sb, "$LogFile restart area specifies "
208				"overflowing client free and/or in use lists.");
209		return false;
210	}
211	/*
212	 * Check ra->seq_number_bits against ra->file_size for consistency.
213	 * We cannot just use ffs() because the file size is not a power of 2.
214	 */
215	file_size = (u64)sle64_to_cpu(ra->file_size);
216	fs_bits = 0;
217	while (file_size) {
218		file_size >>= 1;
219		fs_bits++;
220	}
221	if (le32_to_cpu(ra->seq_number_bits) != 67 - fs_bits) {
222		ntfs_error(vi->i_sb, "$LogFile restart area specifies "
223				"inconsistent sequence number bits.");
224		return false;
225	}
226	/* The log record header length must be a multiple of 8. */
227	if (((le16_to_cpu(ra->log_record_header_length) + 7) & ~7) !=
228			le16_to_cpu(ra->log_record_header_length)) {
229		ntfs_error(vi->i_sb, "$LogFile restart area specifies "
230				"inconsistent log record header length.");
231		return false;
232	}
233	/* Dito for the log page data offset. */
234	if (((le16_to_cpu(ra->log_page_data_offset) + 7) & ~7) !=
235			le16_to_cpu(ra->log_page_data_offset)) {
236		ntfs_error(vi->i_sb, "$LogFile restart area specifies "
237				"inconsistent log page data offset.");
238		return false;
239	}
240	ntfs_debug("Done.");
241	return true;
242}
243
244/**
245 * ntfs_check_log_client_array - check the log client array for consistency
246 * @vi:		$LogFile inode to which the restart page belongs
247 * @rp:		restart page whose log client array to check
248 *
249 * Check the log client array of the restart page @rp for consistency and
250 * return 'true' if it is consistent and 'false' otherwise.
251 *
252 * This function assumes that the restart page header and the restart area have
253 * already been consistency checked.
254 *
255 * Unlike ntfs_check_restart_page_header() and ntfs_check_restart_area(), this
256 * function needs @rp->system_page_size bytes in @rp, i.e. it requires the full
257 * restart page and the page must be multi sector transfer deprotected.
258 */
259static bool ntfs_check_log_client_array(struct inode *vi,
260		RESTART_PAGE_HEADER *rp)
261{
262	RESTART_AREA *ra;
263	LOG_CLIENT_RECORD *ca, *cr;
264	u16 nr_clients, idx;
265	bool in_free_list, idx_is_first;
266
267	ntfs_debug("Entering.");
268	ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
269	ca = (LOG_CLIENT_RECORD*)((u8*)ra +
270			le16_to_cpu(ra->client_array_offset));
271	/*
272	 * Check the ra->client_free_list first and then check the
273	 * ra->client_in_use_list.  Check each of the log client records in
274	 * each of the lists and check that the array does not overflow the
275	 * ra->log_clients value.  Also keep track of the number of records
276	 * visited as there cannot be more than ra->log_clients records and
277	 * that way we detect eventual loops in within a list.
278	 */
279	nr_clients = le16_to_cpu(ra->log_clients);
280	idx = le16_to_cpu(ra->client_free_list);
281	in_free_list = true;
282check_list:
283	for (idx_is_first = true; idx != LOGFILE_NO_CLIENT_CPU; nr_clients--,
284			idx = le16_to_cpu(cr->next_client)) {
285		if (!nr_clients || idx >= le16_to_cpu(ra->log_clients))
286			goto err_out;
287		/* Set @cr to the current log client record. */
288		cr = ca + idx;
289		/* The first log client record must not have a prev_client. */
290		if (idx_is_first) {
291			if (cr->prev_client != LOGFILE_NO_CLIENT)
292				goto err_out;
293			idx_is_first = false;
294		}
295	}
296	/* Switch to and check the in use list if we just did the free list. */
297	if (in_free_list) {
298		in_free_list = false;
299		idx = le16_to_cpu(ra->client_in_use_list);
300		goto check_list;
301	}
302	ntfs_debug("Done.");
303	return true;
304err_out:
305	ntfs_error(vi->i_sb, "$LogFile log client array is corrupt.");
306	return false;
307}
308
309/**
310 * ntfs_check_and_load_restart_page - check the restart page for consistency
311 * @vi:		$LogFile inode to which the restart page belongs
312 * @rp:		restart page to check
313 * @pos:	position in @vi at which the restart page resides
314 * @wrp:	[OUT] copy of the multi sector transfer deprotected restart page
315 * @lsn:	[OUT] set to the current logfile lsn on success
316 *
317 * Check the restart page @rp for consistency and return 0 if it is consistent
318 * and -errno otherwise.  The restart page may have been modified by chkdsk in
319 * which case its magic is CHKD instead of RSTR.
320 *
321 * This function only needs NTFS_BLOCK_SIZE bytes in @rp, i.e. it does not
322 * require the full restart page.
323 *
324 * If @wrp is not NULL, on success, *@wrp will point to a buffer containing a
325 * copy of the complete multi sector transfer deprotected page.  On failure,
326 * *@wrp is undefined.
327 *
328 * Simillarly, if @lsn is not NULL, on success *@lsn will be set to the current
329 * logfile lsn according to this restart page.  On failure, *@lsn is undefined.
330 *
331 * The following error codes are defined:
332 *	-EINVAL	- The restart page is inconsistent.
333 *	-ENOMEM	- Not enough memory to load the restart page.
334 *	-EIO	- Failed to reading from $LogFile.
335 */
336static int ntfs_check_and_load_restart_page(struct inode *vi,
337		RESTART_PAGE_HEADER *rp, s64 pos, RESTART_PAGE_HEADER **wrp,
338		LSN *lsn)
339{
340	RESTART_AREA *ra;
341	RESTART_PAGE_HEADER *trp;
342	int size, err;
343
344	ntfs_debug("Entering.");
345	/* Check the restart page header for consistency. */
346	if (!ntfs_check_restart_page_header(vi, rp, pos)) {
347		/* Error output already done inside the function. */
348		return -EINVAL;
349	}
350	/* Check the restart area for consistency. */
351	if (!ntfs_check_restart_area(vi, rp)) {
352		/* Error output already done inside the function. */
353		return -EINVAL;
354	}
355	ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
356	/*
357	 * Allocate a buffer to store the whole restart page so we can multi
358	 * sector transfer deprotect it.
359	 */
360	trp = ntfs_malloc_nofs(le32_to_cpu(rp->system_page_size));
361	if (!trp) {
362		ntfs_error(vi->i_sb, "Failed to allocate memory for $LogFile "
363				"restart page buffer.");
364		return -ENOMEM;
365	}
366	/*
367	 * Read the whole of the restart page into the buffer.  If it fits
368	 * completely inside @rp, just copy it from there.  Otherwise map all
369	 * the required pages and copy the data from them.
370	 */
371	size = PAGE_SIZE - (pos & ~PAGE_MASK);
372	if (size >= le32_to_cpu(rp->system_page_size)) {
373		memcpy(trp, rp, le32_to_cpu(rp->system_page_size));
374	} else {
375		pgoff_t idx;
376		struct page *page;
377		int have_read, to_read;
378
379		/* First copy what we already have in @rp. */
380		memcpy(trp, rp, size);
381		/* Copy the remaining data one page at a time. */
382		have_read = size;
383		to_read = le32_to_cpu(rp->system_page_size) - size;
384		idx = (pos + size) >> PAGE_SHIFT;
385		BUG_ON((pos + size) & ~PAGE_MASK);
386		do {
387			page = ntfs_map_page(vi->i_mapping, idx);
388			if (IS_ERR(page)) {
389				ntfs_error(vi->i_sb, "Error mapping $LogFile "
390						"page (index %lu).", idx);
391				err = PTR_ERR(page);
392				if (err != -EIO && err != -ENOMEM)
393					err = -EIO;
394				goto err_out;
395			}
396			size = min_t(int, to_read, PAGE_SIZE);
397			memcpy((u8*)trp + have_read, page_address(page), size);
398			ntfs_unmap_page(page);
399			have_read += size;
400			to_read -= size;
401			idx++;
402		} while (to_read > 0);
403	}
404	/*
405	 * Perform the multi sector transfer deprotection on the buffer if the
406	 * restart page is protected.
407	 */
408	if ((!ntfs_is_chkd_record(trp->magic) || le16_to_cpu(trp->usa_count))
409			&& post_read_mst_fixup((NTFS_RECORD*)trp,
410			le32_to_cpu(rp->system_page_size))) {
411		/*
412		 * A multi sector tranfer error was detected.  We only need to
413		 * abort if the restart page contents exceed the multi sector
414		 * transfer fixup of the first sector.
415		 */
416		if (le16_to_cpu(rp->restart_area_offset) +
417				le16_to_cpu(ra->restart_area_length) >
418				NTFS_BLOCK_SIZE - sizeof(u16)) {
419			ntfs_error(vi->i_sb, "Multi sector transfer error "
420					"detected in $LogFile restart page.");
421			err = -EINVAL;
422			goto err_out;
423		}
424	}
425	/*
426	 * If the restart page is modified by chkdsk or there are no active
427	 * logfile clients, the logfile is consistent.  Otherwise, need to
428	 * check the log client records for consistency, too.
429	 */
430	err = 0;
431	if (ntfs_is_rstr_record(rp->magic) &&
432			ra->client_in_use_list != LOGFILE_NO_CLIENT) {
433		if (!ntfs_check_log_client_array(vi, trp)) {
434			err = -EINVAL;
435			goto err_out;
436		}
437	}
438	if (lsn) {
439		if (ntfs_is_rstr_record(rp->magic))
440			*lsn = sle64_to_cpu(ra->current_lsn);
441		else /* if (ntfs_is_chkd_record(rp->magic)) */
442			*lsn = sle64_to_cpu(rp->chkdsk_lsn);
443	}
444	ntfs_debug("Done.");
445	if (wrp)
446		*wrp = trp;
447	else {
448err_out:
449		ntfs_free(trp);
450	}
451	return err;
452}
453
454/**
455 * ntfs_check_logfile - check the journal for consistency
456 * @log_vi:	struct inode of loaded journal $LogFile to check
457 * @rp:		[OUT] on success this is a copy of the current restart page
458 *
459 * Check the $LogFile journal for consistency and return 'true' if it is
460 * consistent and 'false' if not.  On success, the current restart page is
461 * returned in *@rp.  Caller must call ntfs_free(*@rp) when finished with it.
462 *
463 * At present we only check the two restart pages and ignore the log record
464 * pages.
465 *
466 * Note that the MstProtected flag is not set on the $LogFile inode and hence
467 * when reading pages they are not deprotected.  This is because we do not know
468 * if the $LogFile was created on a system with a different page size to ours
469 * yet and mst deprotection would fail if our page size is smaller.
470 */
471bool ntfs_check_logfile(struct inode *log_vi, RESTART_PAGE_HEADER **rp)
472{
473	s64 size, pos;
474	LSN rstr1_lsn, rstr2_lsn;
475	ntfs_volume *vol = NTFS_SB(log_vi->i_sb);
476	struct address_space *mapping = log_vi->i_mapping;
477	struct page *page = NULL;
478	u8 *kaddr = NULL;
479	RESTART_PAGE_HEADER *rstr1_ph = NULL;
480	RESTART_PAGE_HEADER *rstr2_ph = NULL;
481	int log_page_size, err;
482	bool logfile_is_empty = true;
483	u8 log_page_bits;
484
485	ntfs_debug("Entering.");
486	/* An empty $LogFile must have been clean before it got emptied. */
487	if (NVolLogFileEmpty(vol))
488		goto is_empty;
489	size = i_size_read(log_vi);
490	/* Make sure the file doesn't exceed the maximum allowed size. */
491	if (size > MaxLogFileSize)
492		size = MaxLogFileSize;
493	/*
494	 * Truncate size to a multiple of the page cache size or the default
495	 * log page size if the page cache size is between the default log page
496	 * log page size if the page cache size is between the default log page
497	 * size and twice that.
498	 */
499	if (PAGE_SIZE >= DefaultLogPageSize && PAGE_SIZE <=
500			DefaultLogPageSize * 2)
501		log_page_size = DefaultLogPageSize;
502	else
503		log_page_size = PAGE_SIZE;
504	/*
505	 * Use ntfs_ffs() instead of ffs() to enable the compiler to
506	 * optimize log_page_size and log_page_bits into constants.
507	 */
508	log_page_bits = ntfs_ffs(log_page_size) - 1;
509	size &= ~(s64)(log_page_size - 1);
510	/*
511	 * Ensure the log file is big enough to store at least the two restart
512	 * pages and the minimum number of log record pages.
513	 */
514	if (size < log_page_size * 2 || (size - log_page_size * 2) >>
515			log_page_bits < MinLogRecordPages) {
516		ntfs_error(vol->sb, "$LogFile is too small.");
517		return false;
518	}
519	/*
520	 * Read through the file looking for a restart page.  Since the restart
521	 * page header is at the beginning of a page we only need to search at
522	 * what could be the beginning of a page (for each page size) rather
523	 * than scanning the whole file byte by byte.  If all potential places
524	 * contain empty and uninitialzed records, the log file can be assumed
525	 * to be empty.
526	 */
527	for (pos = 0; pos < size; pos <<= 1) {
528		pgoff_t idx = pos >> PAGE_SHIFT;
529		if (!page || page->index != idx) {
530			if (page)
531				ntfs_unmap_page(page);
532			page = ntfs_map_page(mapping, idx);
533			if (IS_ERR(page)) {
534				ntfs_error(vol->sb, "Error mapping $LogFile "
535						"page (index %lu).", idx);
536				goto err_out;
537			}
538		}
539		kaddr = (u8*)page_address(page) + (pos & ~PAGE_MASK);
540		/*
541		 * A non-empty block means the logfile is not empty while an
542		 * empty block after a non-empty block has been encountered
543		 * means we are done.
544		 */
545		if (!ntfs_is_empty_recordp((le32*)kaddr))
546			logfile_is_empty = false;
547		else if (!logfile_is_empty)
548			break;
549		/*
550		 * A log record page means there cannot be a restart page after
551		 * this so no need to continue searching.
552		 */
553		if (ntfs_is_rcrd_recordp((le32*)kaddr))
554			break;
555		/* If not a (modified by chkdsk) restart page, continue. */
556		if (!ntfs_is_rstr_recordp((le32*)kaddr) &&
557				!ntfs_is_chkd_recordp((le32*)kaddr)) {
558			if (!pos)
559				pos = NTFS_BLOCK_SIZE >> 1;
560			continue;
561		}
562		/*
563		 * Check the (modified by chkdsk) restart page for consistency
564		 * and get a copy of the complete multi sector transfer
565		 * deprotected restart page.
566		 */
567		err = ntfs_check_and_load_restart_page(log_vi,
568				(RESTART_PAGE_HEADER*)kaddr, pos,
569				!rstr1_ph ? &rstr1_ph : &rstr2_ph,
570				!rstr1_ph ? &rstr1_lsn : &rstr2_lsn);
571		if (!err) {
572			/*
573			 * If we have now found the first (modified by chkdsk)
574			 * restart page, continue looking for the second one.
575			 */
576			if (!pos) {
577				pos = NTFS_BLOCK_SIZE >> 1;
578				continue;
579			}
580			/*
581			 * We have now found the second (modified by chkdsk)
582			 * restart page, so we can stop looking.
583			 */
584			break;
585		}
586		/*
587		 * Error output already done inside the function.  Note, we do
588		 * not abort if the restart page was invalid as we might still
589		 * find a valid one further in the file.
590		 */
591		if (err != -EINVAL) {
592			ntfs_unmap_page(page);
593			goto err_out;
594		}
595		/* Continue looking. */
596		if (!pos)
597			pos = NTFS_BLOCK_SIZE >> 1;
598	}
599	if (page)
600		ntfs_unmap_page(page);
601	if (logfile_is_empty) {
602		NVolSetLogFileEmpty(vol);
603is_empty:
604		ntfs_debug("Done.  ($LogFile is empty.)");
605		return true;
606	}
607	if (!rstr1_ph) {
608		BUG_ON(rstr2_ph);
609		ntfs_error(vol->sb, "Did not find any restart pages in "
610				"$LogFile and it was not empty.");
611		return false;
612	}
613	/* If both restart pages were found, use the more recent one. */
614	if (rstr2_ph) {
615		/*
616		 * If the second restart area is more recent, switch to it.
617		 * Otherwise just throw it away.
618		 */
619		if (rstr2_lsn > rstr1_lsn) {
620			ntfs_debug("Using second restart page as it is more "
621					"recent.");
622			ntfs_free(rstr1_ph);
623			rstr1_ph = rstr2_ph;
624			/* rstr1_lsn = rstr2_lsn; */
625		} else {
626			ntfs_debug("Using first restart page as it is more "
627					"recent.");
628			ntfs_free(rstr2_ph);
629		}
630		rstr2_ph = NULL;
631	}
632	/* All consistency checks passed. */
633	if (rp)
634		*rp = rstr1_ph;
635	else
636		ntfs_free(rstr1_ph);
637	ntfs_debug("Done.");
638	return true;
639err_out:
640	if (rstr1_ph)
641		ntfs_free(rstr1_ph);
642	return false;
643}
644
645/**
646 * ntfs_is_logfile_clean - check in the journal if the volume is clean
647 * @log_vi:	struct inode of loaded journal $LogFile to check
648 * @rp:		copy of the current restart page
649 *
650 * Analyze the $LogFile journal and return 'true' if it indicates the volume was
651 * shutdown cleanly and 'false' if not.
652 *
653 * At present we only look at the two restart pages and ignore the log record
654 * pages.  This is a little bit crude in that there will be a very small number
655 * of cases where we think that a volume is dirty when in fact it is clean.
656 * This should only affect volumes that have not been shutdown cleanly but did
657 * not have any pending, non-check-pointed i/o, i.e. they were completely idle
658 * at least for the five seconds preceding the unclean shutdown.
659 *
660 * This function assumes that the $LogFile journal has already been consistency
661 * checked by a call to ntfs_check_logfile() and in particular if the $LogFile
662 * is empty this function requires that NVolLogFileEmpty() is true otherwise an
663 * empty volume will be reported as dirty.
664 */
665bool ntfs_is_logfile_clean(struct inode *log_vi, const RESTART_PAGE_HEADER *rp)
666{
667	ntfs_volume *vol = NTFS_SB(log_vi->i_sb);
668	RESTART_AREA *ra;
669
670	ntfs_debug("Entering.");
671	/* An empty $LogFile must have been clean before it got emptied. */
672	if (NVolLogFileEmpty(vol)) {
673		ntfs_debug("Done.  ($LogFile is empty.)");
674		return true;
675	}
676	BUG_ON(!rp);
677	if (!ntfs_is_rstr_record(rp->magic) &&
678			!ntfs_is_chkd_record(rp->magic)) {
679		ntfs_error(vol->sb, "Restart page buffer is invalid.  This is "
680				"probably a bug in that the $LogFile should "
681				"have been consistency checked before calling "
682				"this function.");
683		return false;
684	}
685	ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
686	/*
687	 * If the $LogFile has active clients, i.e. it is open, and we do not
688	 * have the RESTART_VOLUME_IS_CLEAN bit set in the restart area flags,
689	 * we assume there was an unclean shutdown.
690	 */
691	if (ra->client_in_use_list != LOGFILE_NO_CLIENT &&
692			!(ra->flags & RESTART_VOLUME_IS_CLEAN)) {
693		ntfs_debug("Done.  $LogFile indicates a dirty shutdown.");
694		return false;
695	}
696	/* $LogFile indicates a clean shutdown. */
697	ntfs_debug("Done.  $LogFile indicates a clean shutdown.");
698	return true;
699}
700
701/**
702 * ntfs_empty_logfile - empty the contents of the $LogFile journal
703 * @log_vi:	struct inode of loaded journal $LogFile to empty
704 *
705 * Empty the contents of the $LogFile journal @log_vi and return 'true' on
706 * success and 'false' on error.
707 *
708 * This function assumes that the $LogFile journal has already been consistency
709 * checked by a call to ntfs_check_logfile() and that ntfs_is_logfile_clean()
710 * has been used to ensure that the $LogFile is clean.
711 */
712bool ntfs_empty_logfile(struct inode *log_vi)
713{
714	VCN vcn, end_vcn;
715	ntfs_inode *log_ni = NTFS_I(log_vi);
716	ntfs_volume *vol = log_ni->vol;
717	struct super_block *sb = vol->sb;
718	runlist_element *rl;
719	unsigned long flags;
720	unsigned block_size, block_size_bits;
721	int err;
722	bool should_wait = true;
723
724	ntfs_debug("Entering.");
725	if (NVolLogFileEmpty(vol)) {
726		ntfs_debug("Done.");
727		return true;
728	}
729	/*
730	 * We cannot use ntfs_attr_set() because we may be still in the middle
731	 * of a mount operation.  Thus we do the emptying by hand by first
732	 * zapping the page cache pages for the $LogFile/$DATA attribute and
733	 * then emptying each of the buffers in each of the clusters specified
734	 * by the runlist by hand.
735	 */
736	block_size = sb->s_blocksize;
737	block_size_bits = sb->s_blocksize_bits;
738	vcn = 0;
739	read_lock_irqsave(&log_ni->size_lock, flags);
740	end_vcn = (log_ni->initialized_size + vol->cluster_size_mask) >>
741			vol->cluster_size_bits;
742	read_unlock_irqrestore(&log_ni->size_lock, flags);
743	truncate_inode_pages(log_vi->i_mapping, 0);
744	down_write(&log_ni->runlist.lock);
745	rl = log_ni->runlist.rl;
746	if (unlikely(!rl || vcn < rl->vcn || !rl->length)) {
747map_vcn:
748		err = ntfs_map_runlist_nolock(log_ni, vcn, NULL);
749		if (err) {
750			ntfs_error(sb, "Failed to map runlist fragment (error "
751					"%d).", -err);
752			goto err;
753		}
754		rl = log_ni->runlist.rl;
755		BUG_ON(!rl || vcn < rl->vcn || !rl->length);
756	}
757	/* Seek to the runlist element containing @vcn. */
758	while (rl->length && vcn >= rl[1].vcn)
759		rl++;
760	do {
761		LCN lcn;
762		sector_t block, end_block;
763		s64 len;
764
765		/*
766		 * If this run is not mapped map it now and start again as the
767		 * runlist will have been updated.
768		 */
769		lcn = rl->lcn;
770		if (unlikely(lcn == LCN_RL_NOT_MAPPED)) {
771			vcn = rl->vcn;
772			goto map_vcn;
773		}
774		/* If this run is not valid abort with an error. */
775		if (unlikely(!rl->length || lcn < LCN_HOLE))
776			goto rl_err;
777		/* Skip holes. */
778		if (lcn == LCN_HOLE)
779			continue;
780		block = lcn << vol->cluster_size_bits >> block_size_bits;
781		len = rl->length;
782		if (rl[1].vcn > end_vcn)
783			len = end_vcn - rl->vcn;
784		end_block = (lcn + len) << vol->cluster_size_bits >>
785				block_size_bits;
786		/* Iterate over the blocks in the run and empty them. */
787		do {
788			struct buffer_head *bh;
789
790			/* Obtain the buffer, possibly not uptodate. */
791			bh = sb_getblk(sb, block);
792			BUG_ON(!bh);
793			/* Setup buffer i/o submission. */
794			lock_buffer(bh);
795			bh->b_end_io = end_buffer_write_sync;
796			get_bh(bh);
797			/* Set the entire contents of the buffer to 0xff. */
798			memset(bh->b_data, -1, block_size);
799			if (!buffer_uptodate(bh))
800				set_buffer_uptodate(bh);
801			if (buffer_dirty(bh))
802				clear_buffer_dirty(bh);
803			/*
804			 * Submit the buffer and wait for i/o to complete but
805			 * only for the first buffer so we do not miss really
806			 * serious i/o errors.  Once the first buffer has
807			 * completed ignore errors afterwards as we can assume
808			 * that if one buffer worked all of them will work.
809			 */
810			submit_bh(REQ_OP_WRITE, bh);
811			if (should_wait) {
812				should_wait = false;
813				wait_on_buffer(bh);
814				if (unlikely(!buffer_uptodate(bh)))
815					goto io_err;
816			}
817			brelse(bh);
818		} while (++block < end_block);
819	} while ((++rl)->vcn < end_vcn);
820	up_write(&log_ni->runlist.lock);
821	/*
822	 * Zap the pages again just in case any got instantiated whilst we were
823	 * emptying the blocks by hand.  FIXME: We may not have completed
824	 * writing to all the buffer heads yet so this may happen too early.
825	 * We really should use a kernel thread to do the emptying
826	 * asynchronously and then we can also set the volume dirty and output
827	 * an error message if emptying should fail.
828	 */
829	truncate_inode_pages(log_vi->i_mapping, 0);
830	/* Set the flag so we do not have to do it again on remount. */
831	NVolSetLogFileEmpty(vol);
832	ntfs_debug("Done.");
833	return true;
834io_err:
835	ntfs_error(sb, "Failed to write buffer.  Unmount and run chkdsk.");
836	goto dirty_err;
837rl_err:
838	ntfs_error(sb, "Runlist is corrupt.  Unmount and run chkdsk.");
839dirty_err:
840	NVolSetErrors(vol);
841	err = -EIO;
842err:
843	up_write(&log_ni->runlist.lock);
844	ntfs_error(sb, "Failed to fill $LogFile with 0xff bytes (error %d).",
845			-err);
846	return false;
847}
848
849#endif /* NTFS_RW */