xref: /openbmc/linux/fs/ntfs/logfile.c (revision 22246614)
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 
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 	VCN vcn, end_vcn;
728 	ntfs_inode *log_ni = NTFS_I(log_vi);
729 	ntfs_volume *vol = log_ni->vol;
730 	struct super_block *sb = vol->sb;
731 	runlist_element *rl;
732 	unsigned long flags;
733 	unsigned block_size, block_size_bits;
734 	int err;
735 	bool should_wait = true;
736 
737 	ntfs_debug("Entering.");
738 	if (NVolLogFileEmpty(vol)) {
739 		ntfs_debug("Done.");
740 		return true;
741 	}
742 	/*
743 	 * We cannot use ntfs_attr_set() because we may be still in the middle
744 	 * of a mount operation.  Thus we do the emptying by hand by first
745 	 * zapping the page cache pages for the $LogFile/$DATA attribute and
746 	 * then emptying each of the buffers in each of the clusters specified
747 	 * by the runlist by hand.
748 	 */
749 	block_size = sb->s_blocksize;
750 	block_size_bits = sb->s_blocksize_bits;
751 	vcn = 0;
752 	read_lock_irqsave(&log_ni->size_lock, flags);
753 	end_vcn = (log_ni->initialized_size + vol->cluster_size_mask) >>
754 			vol->cluster_size_bits;
755 	read_unlock_irqrestore(&log_ni->size_lock, flags);
756 	truncate_inode_pages(log_vi->i_mapping, 0);
757 	down_write(&log_ni->runlist.lock);
758 	rl = log_ni->runlist.rl;
759 	if (unlikely(!rl || vcn < rl->vcn || !rl->length)) {
760 map_vcn:
761 		err = ntfs_map_runlist_nolock(log_ni, vcn, NULL);
762 		if (err) {
763 			ntfs_error(sb, "Failed to map runlist fragment (error "
764 					"%d).", -err);
765 			goto err;
766 		}
767 		rl = log_ni->runlist.rl;
768 		BUG_ON(!rl || vcn < rl->vcn || !rl->length);
769 	}
770 	/* Seek to the runlist element containing @vcn. */
771 	while (rl->length && vcn >= rl[1].vcn)
772 		rl++;
773 	do {
774 		LCN lcn;
775 		sector_t block, end_block;
776 		s64 len;
777 
778 		/*
779 		 * If this run is not mapped map it now and start again as the
780 		 * runlist will have been updated.
781 		 */
782 		lcn = rl->lcn;
783 		if (unlikely(lcn == LCN_RL_NOT_MAPPED)) {
784 			vcn = rl->vcn;
785 			goto map_vcn;
786 		}
787 		/* If this run is not valid abort with an error. */
788 		if (unlikely(!rl->length || lcn < LCN_HOLE))
789 			goto rl_err;
790 		/* Skip holes. */
791 		if (lcn == LCN_HOLE)
792 			continue;
793 		block = lcn << vol->cluster_size_bits >> block_size_bits;
794 		len = rl->length;
795 		if (rl[1].vcn > end_vcn)
796 			len = end_vcn - rl->vcn;
797 		end_block = (lcn + len) << vol->cluster_size_bits >>
798 				block_size_bits;
799 		/* Iterate over the blocks in the run and empty them. */
800 		do {
801 			struct buffer_head *bh;
802 
803 			/* Obtain the buffer, possibly not uptodate. */
804 			bh = sb_getblk(sb, block);
805 			BUG_ON(!bh);
806 			/* Setup buffer i/o submission. */
807 			lock_buffer(bh);
808 			bh->b_end_io = end_buffer_write_sync;
809 			get_bh(bh);
810 			/* Set the entire contents of the buffer to 0xff. */
811 			memset(bh->b_data, -1, block_size);
812 			if (!buffer_uptodate(bh))
813 				set_buffer_uptodate(bh);
814 			if (buffer_dirty(bh))
815 				clear_buffer_dirty(bh);
816 			/*
817 			 * Submit the buffer and wait for i/o to complete but
818 			 * only for the first buffer so we do not miss really
819 			 * serious i/o errors.  Once the first buffer has
820 			 * completed ignore errors afterwards as we can assume
821 			 * that if one buffer worked all of them will work.
822 			 */
823 			submit_bh(WRITE, bh);
824 			if (should_wait) {
825 				should_wait = false;
826 				wait_on_buffer(bh);
827 				if (unlikely(!buffer_uptodate(bh)))
828 					goto io_err;
829 			}
830 			brelse(bh);
831 		} while (++block < end_block);
832 	} while ((++rl)->vcn < end_vcn);
833 	up_write(&log_ni->runlist.lock);
834 	/*
835 	 * Zap the pages again just in case any got instantiated whilst we were
836 	 * emptying the blocks by hand.  FIXME: We may not have completed
837 	 * writing to all the buffer heads yet so this may happen too early.
838 	 * We really should use a kernel thread to do the emptying
839 	 * asynchronously and then we can also set the volume dirty and output
840 	 * an error message if emptying should fail.
841 	 */
842 	truncate_inode_pages(log_vi->i_mapping, 0);
843 	/* Set the flag so we do not have to do it again on remount. */
844 	NVolSetLogFileEmpty(vol);
845 	ntfs_debug("Done.");
846 	return true;
847 io_err:
848 	ntfs_error(sb, "Failed to write buffer.  Unmount and run chkdsk.");
849 	goto dirty_err;
850 rl_err:
851 	ntfs_error(sb, "Runlist is corrupt.  Unmount and run chkdsk.");
852 dirty_err:
853 	NVolSetErrors(vol);
854 	err = -EIO;
855 err:
856 	up_write(&log_ni->runlist.lock);
857 	ntfs_error(sb, "Failed to fill $LogFile with 0xff bytes (error %d).",
858 			-err);
859 	return false;
860 }
861 
862 #endif /* NTFS_RW */
863