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 #include <linux/bio.h>
31 
32 #include "attrib.h"
33 #include "aops.h"
34 #include "debug.h"
35 #include "logfile.h"
36 #include "malloc.h"
37 #include "volume.h"
38 #include "ntfs.h"
39 
40 /**
41  * ntfs_check_restart_page_header - check the page header for consistency
42  * @vi:		$LogFile inode to which the restart page header belongs
43  * @rp:		restart page header to check
44  * @pos:	position in @vi at which the restart page header resides
45  *
46  * Check the restart page header @rp for consistency and return 'true' if it is
47  * consistent and 'false' otherwise.
48  *
49  * This function only needs NTFS_BLOCK_SIZE bytes in @rp, i.e. it does not
50  * require the full restart page.
51  */
ntfs_check_restart_page_header(struct inode * vi,RESTART_PAGE_HEADER * rp,s64 pos)52 static bool ntfs_check_restart_page_header(struct inode *vi,
53 		RESTART_PAGE_HEADER *rp, s64 pos)
54 {
55 	u32 logfile_system_page_size, logfile_log_page_size;
56 	u16 ra_ofs, usa_count, usa_ofs, usa_end = 0;
57 	bool have_usa = true;
58 
59 	ntfs_debug("Entering.");
60 	/*
61 	 * If the system or log page sizes are smaller than the ntfs block size
62 	 * or either is not a power of 2 we cannot handle this log file.
63 	 */
64 	logfile_system_page_size = le32_to_cpu(rp->system_page_size);
65 	logfile_log_page_size = le32_to_cpu(rp->log_page_size);
66 	if (logfile_system_page_size < NTFS_BLOCK_SIZE ||
67 			logfile_log_page_size < NTFS_BLOCK_SIZE ||
68 			logfile_system_page_size &
69 			(logfile_system_page_size - 1) ||
70 			!is_power_of_2(logfile_log_page_size)) {
71 		ntfs_error(vi->i_sb, "$LogFile uses unsupported page size.");
72 		return false;
73 	}
74 	/*
75 	 * We must be either at !pos (1st restart page) or at pos = system page
76 	 * size (2nd restart page).
77 	 */
78 	if (pos && pos != logfile_system_page_size) {
79 		ntfs_error(vi->i_sb, "Found restart area in incorrect "
80 				"position in $LogFile.");
81 		return false;
82 	}
83 	/* We only know how to handle version 1.1. */
84 	if (sle16_to_cpu(rp->major_ver) != 1 ||
85 			sle16_to_cpu(rp->minor_ver) != 1) {
86 		ntfs_error(vi->i_sb, "$LogFile version %i.%i is not "
87 				"supported.  (This driver supports version "
88 				"1.1 only.)", (int)sle16_to_cpu(rp->major_ver),
89 				(int)sle16_to_cpu(rp->minor_ver));
90 		return false;
91 	}
92 	/*
93 	 * If chkdsk has been run the restart page may not be protected by an
94 	 * update sequence array.
95 	 */
96 	if (ntfs_is_chkd_record(rp->magic) && !le16_to_cpu(rp->usa_count)) {
97 		have_usa = false;
98 		goto skip_usa_checks;
99 	}
100 	/* Verify the size of the update sequence array. */
101 	usa_count = 1 + (logfile_system_page_size >> NTFS_BLOCK_SIZE_BITS);
102 	if (usa_count != le16_to_cpu(rp->usa_count)) {
103 		ntfs_error(vi->i_sb, "$LogFile restart page specifies "
104 				"inconsistent update sequence array count.");
105 		return false;
106 	}
107 	/* Verify the position of the update sequence array. */
108 	usa_ofs = le16_to_cpu(rp->usa_ofs);
109 	usa_end = usa_ofs + usa_count * sizeof(u16);
110 	if (usa_ofs < sizeof(RESTART_PAGE_HEADER) ||
111 			usa_end > NTFS_BLOCK_SIZE - sizeof(u16)) {
112 		ntfs_error(vi->i_sb, "$LogFile restart page specifies "
113 				"inconsistent update sequence array offset.");
114 		return false;
115 	}
116 skip_usa_checks:
117 	/*
118 	 * Verify the position of the restart area.  It must be:
119 	 *	- aligned to 8-byte boundary,
120 	 *	- after the update sequence array, and
121 	 *	- within the system page size.
122 	 */
123 	ra_ofs = le16_to_cpu(rp->restart_area_offset);
124 	if (ra_ofs & 7 || (have_usa ? ra_ofs < usa_end :
125 			ra_ofs < sizeof(RESTART_PAGE_HEADER)) ||
126 			ra_ofs > logfile_system_page_size) {
127 		ntfs_error(vi->i_sb, "$LogFile restart page specifies "
128 				"inconsistent restart area offset.");
129 		return false;
130 	}
131 	/*
132 	 * Only restart pages modified by chkdsk are allowed to have chkdsk_lsn
133 	 * set.
134 	 */
135 	if (!ntfs_is_chkd_record(rp->magic) && sle64_to_cpu(rp->chkdsk_lsn)) {
136 		ntfs_error(vi->i_sb, "$LogFile restart page is not modified "
137 				"by chkdsk but a chkdsk LSN is specified.");
138 		return false;
139 	}
140 	ntfs_debug("Done.");
141 	return true;
142 }
143 
144 /**
145  * ntfs_check_restart_area - check the restart area for consistency
146  * @vi:		$LogFile inode to which the restart page belongs
147  * @rp:		restart page whose restart area to check
148  *
149  * Check the restart area of the restart page @rp for consistency and return
150  * 'true' if it is consistent and 'false' otherwise.
151  *
152  * This function assumes that the restart page header has already been
153  * consistency checked.
154  *
155  * This function only needs NTFS_BLOCK_SIZE bytes in @rp, i.e. it does not
156  * require the full restart page.
157  */
ntfs_check_restart_area(struct inode * vi,RESTART_PAGE_HEADER * rp)158 static bool ntfs_check_restart_area(struct inode *vi, RESTART_PAGE_HEADER *rp)
159 {
160 	u64 file_size;
161 	RESTART_AREA *ra;
162 	u16 ra_ofs, ra_len, ca_ofs;
163 	u8 fs_bits;
164 
165 	ntfs_debug("Entering.");
166 	ra_ofs = le16_to_cpu(rp->restart_area_offset);
167 	ra = (RESTART_AREA*)((u8*)rp + ra_ofs);
168 	/*
169 	 * Everything before ra->file_size must be before the first word
170 	 * protected by an update sequence number.  This ensures that it is
171 	 * safe to access ra->client_array_offset.
172 	 */
173 	if (ra_ofs + offsetof(RESTART_AREA, file_size) >
174 			NTFS_BLOCK_SIZE - sizeof(u16)) {
175 		ntfs_error(vi->i_sb, "$LogFile restart area specifies "
176 				"inconsistent file offset.");
177 		return false;
178 	}
179 	/*
180 	 * Now that we can access ra->client_array_offset, make sure everything
181 	 * up to the log client array is before the first word protected by an
182 	 * update sequence number.  This ensures we can access all of the
183 	 * restart area elements safely.  Also, the client array offset must be
184 	 * aligned to an 8-byte boundary.
185 	 */
186 	ca_ofs = le16_to_cpu(ra->client_array_offset);
187 	if (((ca_ofs + 7) & ~7) != ca_ofs ||
188 			ra_ofs + ca_ofs > NTFS_BLOCK_SIZE - sizeof(u16)) {
189 		ntfs_error(vi->i_sb, "$LogFile restart area specifies "
190 				"inconsistent client array offset.");
191 		return false;
192 	}
193 	/*
194 	 * The restart area must end within the system page size both when
195 	 * calculated manually and as specified by ra->restart_area_length.
196 	 * Also, the calculated length must not exceed the specified length.
197 	 */
198 	ra_len = ca_ofs + le16_to_cpu(ra->log_clients) *
199 			sizeof(LOG_CLIENT_RECORD);
200 	if (ra_ofs + ra_len > le32_to_cpu(rp->system_page_size) ||
201 			ra_ofs + le16_to_cpu(ra->restart_area_length) >
202 			le32_to_cpu(rp->system_page_size) ||
203 			ra_len > le16_to_cpu(ra->restart_area_length)) {
204 		ntfs_error(vi->i_sb, "$LogFile restart area is out of bounds "
205 				"of the system page size specified by the "
206 				"restart page header and/or the specified "
207 				"restart area length is inconsistent.");
208 		return false;
209 	}
210 	/*
211 	 * The ra->client_free_list and ra->client_in_use_list must be either
212 	 * LOGFILE_NO_CLIENT or less than ra->log_clients or they are
213 	 * overflowing the client array.
214 	 */
215 	if ((ra->client_free_list != LOGFILE_NO_CLIENT &&
216 			le16_to_cpu(ra->client_free_list) >=
217 			le16_to_cpu(ra->log_clients)) ||
218 			(ra->client_in_use_list != LOGFILE_NO_CLIENT &&
219 			le16_to_cpu(ra->client_in_use_list) >=
220 			le16_to_cpu(ra->log_clients))) {
221 		ntfs_error(vi->i_sb, "$LogFile restart area specifies "
222 				"overflowing client free and/or in use lists.");
223 		return false;
224 	}
225 	/*
226 	 * Check ra->seq_number_bits against ra->file_size for consistency.
227 	 * We cannot just use ffs() because the file size is not a power of 2.
228 	 */
229 	file_size = (u64)sle64_to_cpu(ra->file_size);
230 	fs_bits = 0;
231 	while (file_size) {
232 		file_size >>= 1;
233 		fs_bits++;
234 	}
235 	if (le32_to_cpu(ra->seq_number_bits) != 67 - fs_bits) {
236 		ntfs_error(vi->i_sb, "$LogFile restart area specifies "
237 				"inconsistent sequence number bits.");
238 		return false;
239 	}
240 	/* The log record header length must be a multiple of 8. */
241 	if (((le16_to_cpu(ra->log_record_header_length) + 7) & ~7) !=
242 			le16_to_cpu(ra->log_record_header_length)) {
243 		ntfs_error(vi->i_sb, "$LogFile restart area specifies "
244 				"inconsistent log record header length.");
245 		return false;
246 	}
247 	/* Dito for the log page data offset. */
248 	if (((le16_to_cpu(ra->log_page_data_offset) + 7) & ~7) !=
249 			le16_to_cpu(ra->log_page_data_offset)) {
250 		ntfs_error(vi->i_sb, "$LogFile restart area specifies "
251 				"inconsistent log page data offset.");
252 		return false;
253 	}
254 	ntfs_debug("Done.");
255 	return true;
256 }
257 
258 /**
259  * ntfs_check_log_client_array - check the log client array for consistency
260  * @vi:		$LogFile inode to which the restart page belongs
261  * @rp:		restart page whose log client array to check
262  *
263  * Check the log client array of the restart page @rp for consistency and
264  * return 'true' if it is consistent and 'false' otherwise.
265  *
266  * This function assumes that the restart page header and the restart area have
267  * already been consistency checked.
268  *
269  * Unlike ntfs_check_restart_page_header() and ntfs_check_restart_area(), this
270  * function needs @rp->system_page_size bytes in @rp, i.e. it requires the full
271  * restart page and the page must be multi sector transfer deprotected.
272  */
ntfs_check_log_client_array(struct inode * vi,RESTART_PAGE_HEADER * rp)273 static bool ntfs_check_log_client_array(struct inode *vi,
274 		RESTART_PAGE_HEADER *rp)
275 {
276 	RESTART_AREA *ra;
277 	LOG_CLIENT_RECORD *ca, *cr;
278 	u16 nr_clients, idx;
279 	bool in_free_list, idx_is_first;
280 
281 	ntfs_debug("Entering.");
282 	ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
283 	ca = (LOG_CLIENT_RECORD*)((u8*)ra +
284 			le16_to_cpu(ra->client_array_offset));
285 	/*
286 	 * Check the ra->client_free_list first and then check the
287 	 * ra->client_in_use_list.  Check each of the log client records in
288 	 * each of the lists and check that the array does not overflow the
289 	 * ra->log_clients value.  Also keep track of the number of records
290 	 * visited as there cannot be more than ra->log_clients records and
291 	 * that way we detect eventual loops in within a list.
292 	 */
293 	nr_clients = le16_to_cpu(ra->log_clients);
294 	idx = le16_to_cpu(ra->client_free_list);
295 	in_free_list = true;
296 check_list:
297 	for (idx_is_first = true; idx != LOGFILE_NO_CLIENT_CPU; nr_clients--,
298 			idx = le16_to_cpu(cr->next_client)) {
299 		if (!nr_clients || idx >= le16_to_cpu(ra->log_clients))
300 			goto err_out;
301 		/* Set @cr to the current log client record. */
302 		cr = ca + idx;
303 		/* The first log client record must not have a prev_client. */
304 		if (idx_is_first) {
305 			if (cr->prev_client != LOGFILE_NO_CLIENT)
306 				goto err_out;
307 			idx_is_first = false;
308 		}
309 	}
310 	/* Switch to and check the in use list if we just did the free list. */
311 	if (in_free_list) {
312 		in_free_list = false;
313 		idx = le16_to_cpu(ra->client_in_use_list);
314 		goto check_list;
315 	}
316 	ntfs_debug("Done.");
317 	return true;
318 err_out:
319 	ntfs_error(vi->i_sb, "$LogFile log client array is corrupt.");
320 	return false;
321 }
322 
323 /**
324  * ntfs_check_and_load_restart_page - check the restart page for consistency
325  * @vi:		$LogFile inode to which the restart page belongs
326  * @rp:		restart page to check
327  * @pos:	position in @vi at which the restart page resides
328  * @wrp:	[OUT] copy of the multi sector transfer deprotected restart page
329  * @lsn:	[OUT] set to the current logfile lsn on success
330  *
331  * Check the restart page @rp for consistency and return 0 if it is consistent
332  * and -errno otherwise.  The restart page may have been modified by chkdsk in
333  * which case its magic is CHKD instead of RSTR.
334  *
335  * This function only needs NTFS_BLOCK_SIZE bytes in @rp, i.e. it does not
336  * require the full restart page.
337  *
338  * If @wrp is not NULL, on success, *@wrp will point to a buffer containing a
339  * copy of the complete multi sector transfer deprotected page.  On failure,
340  * *@wrp is undefined.
341  *
342  * Simillarly, if @lsn is not NULL, on success *@lsn will be set to the current
343  * logfile lsn according to this restart page.  On failure, *@lsn is undefined.
344  *
345  * The following error codes are defined:
346  *	-EINVAL	- The restart page is inconsistent.
347  *	-ENOMEM	- Not enough memory to load the restart page.
348  *	-EIO	- Failed to reading from $LogFile.
349  */
ntfs_check_and_load_restart_page(struct inode * vi,RESTART_PAGE_HEADER * rp,s64 pos,RESTART_PAGE_HEADER ** wrp,LSN * lsn)350 static int ntfs_check_and_load_restart_page(struct inode *vi,
351 		RESTART_PAGE_HEADER *rp, s64 pos, RESTART_PAGE_HEADER **wrp,
352 		LSN *lsn)
353 {
354 	RESTART_AREA *ra;
355 	RESTART_PAGE_HEADER *trp;
356 	int size, err;
357 
358 	ntfs_debug("Entering.");
359 	/* Check the restart page header for consistency. */
360 	if (!ntfs_check_restart_page_header(vi, rp, pos)) {
361 		/* Error output already done inside the function. */
362 		return -EINVAL;
363 	}
364 	/* Check the restart area for consistency. */
365 	if (!ntfs_check_restart_area(vi, rp)) {
366 		/* Error output already done inside the function. */
367 		return -EINVAL;
368 	}
369 	ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
370 	/*
371 	 * Allocate a buffer to store the whole restart page so we can multi
372 	 * sector transfer deprotect it.
373 	 */
374 	trp = ntfs_malloc_nofs(le32_to_cpu(rp->system_page_size));
375 	if (!trp) {
376 		ntfs_error(vi->i_sb, "Failed to allocate memory for $LogFile "
377 				"restart page buffer.");
378 		return -ENOMEM;
379 	}
380 	/*
381 	 * Read the whole of the restart page into the buffer.  If it fits
382 	 * completely inside @rp, just copy it from there.  Otherwise map all
383 	 * the required pages and copy the data from them.
384 	 */
385 	size = PAGE_SIZE - (pos & ~PAGE_MASK);
386 	if (size >= le32_to_cpu(rp->system_page_size)) {
387 		memcpy(trp, rp, le32_to_cpu(rp->system_page_size));
388 	} else {
389 		pgoff_t idx;
390 		struct page *page;
391 		int have_read, to_read;
392 
393 		/* First copy what we already have in @rp. */
394 		memcpy(trp, rp, size);
395 		/* Copy the remaining data one page at a time. */
396 		have_read = size;
397 		to_read = le32_to_cpu(rp->system_page_size) - size;
398 		idx = (pos + size) >> PAGE_SHIFT;
399 		BUG_ON((pos + size) & ~PAGE_MASK);
400 		do {
401 			page = ntfs_map_page(vi->i_mapping, idx);
402 			if (IS_ERR(page)) {
403 				ntfs_error(vi->i_sb, "Error mapping $LogFile "
404 						"page (index %lu).", idx);
405 				err = PTR_ERR(page);
406 				if (err != -EIO && err != -ENOMEM)
407 					err = -EIO;
408 				goto err_out;
409 			}
410 			size = min_t(int, to_read, PAGE_SIZE);
411 			memcpy((u8*)trp + have_read, page_address(page), size);
412 			ntfs_unmap_page(page);
413 			have_read += size;
414 			to_read -= size;
415 			idx++;
416 		} while (to_read > 0);
417 	}
418 	/*
419 	 * Perform the multi sector transfer deprotection on the buffer if the
420 	 * restart page is protected.
421 	 */
422 	if ((!ntfs_is_chkd_record(trp->magic) || le16_to_cpu(trp->usa_count))
423 			&& post_read_mst_fixup((NTFS_RECORD*)trp,
424 			le32_to_cpu(rp->system_page_size))) {
425 		/*
426 		 * A multi sector tranfer error was detected.  We only need to
427 		 * abort if the restart page contents exceed the multi sector
428 		 * transfer fixup of the first sector.
429 		 */
430 		if (le16_to_cpu(rp->restart_area_offset) +
431 				le16_to_cpu(ra->restart_area_length) >
432 				NTFS_BLOCK_SIZE - sizeof(u16)) {
433 			ntfs_error(vi->i_sb, "Multi sector transfer error "
434 					"detected in $LogFile restart page.");
435 			err = -EINVAL;
436 			goto err_out;
437 		}
438 	}
439 	/*
440 	 * If the restart page is modified by chkdsk or there are no active
441 	 * logfile clients, the logfile is consistent.  Otherwise, need to
442 	 * check the log client records for consistency, too.
443 	 */
444 	err = 0;
445 	if (ntfs_is_rstr_record(rp->magic) &&
446 			ra->client_in_use_list != LOGFILE_NO_CLIENT) {
447 		if (!ntfs_check_log_client_array(vi, trp)) {
448 			err = -EINVAL;
449 			goto err_out;
450 		}
451 	}
452 	if (lsn) {
453 		if (ntfs_is_rstr_record(rp->magic))
454 			*lsn = sle64_to_cpu(ra->current_lsn);
455 		else /* if (ntfs_is_chkd_record(rp->magic)) */
456 			*lsn = sle64_to_cpu(rp->chkdsk_lsn);
457 	}
458 	ntfs_debug("Done.");
459 	if (wrp)
460 		*wrp = trp;
461 	else {
462 err_out:
463 		ntfs_free(trp);
464 	}
465 	return err;
466 }
467 
468 /**
469  * ntfs_check_logfile - check the journal for consistency
470  * @log_vi:	struct inode of loaded journal $LogFile to check
471  * @rp:		[OUT] on success this is a copy of the current restart page
472  *
473  * Check the $LogFile journal for consistency and return 'true' if it is
474  * consistent and 'false' if not.  On success, the current restart page is
475  * returned in *@rp.  Caller must call ntfs_free(*@rp) when finished with it.
476  *
477  * At present we only check the two restart pages and ignore the log record
478  * pages.
479  *
480  * Note that the MstProtected flag is not set on the $LogFile inode and hence
481  * when reading pages they are not deprotected.  This is because we do not know
482  * if the $LogFile was created on a system with a different page size to ours
483  * yet and mst deprotection would fail if our page size is smaller.
484  */
ntfs_check_logfile(struct inode * log_vi,RESTART_PAGE_HEADER ** rp)485 bool ntfs_check_logfile(struct inode *log_vi, RESTART_PAGE_HEADER **rp)
486 {
487 	s64 size, pos;
488 	LSN rstr1_lsn, rstr2_lsn;
489 	ntfs_volume *vol = NTFS_SB(log_vi->i_sb);
490 	struct address_space *mapping = log_vi->i_mapping;
491 	struct page *page = NULL;
492 	u8 *kaddr = NULL;
493 	RESTART_PAGE_HEADER *rstr1_ph = NULL;
494 	RESTART_PAGE_HEADER *rstr2_ph = NULL;
495 	int log_page_size, log_page_mask, err;
496 	bool logfile_is_empty = true;
497 	u8 log_page_bits;
498 
499 	ntfs_debug("Entering.");
500 	/* An empty $LogFile must have been clean before it got emptied. */
501 	if (NVolLogFileEmpty(vol))
502 		goto is_empty;
503 	size = i_size_read(log_vi);
504 	/* Make sure the file doesn't exceed the maximum allowed size. */
505 	if (size > MaxLogFileSize)
506 		size = MaxLogFileSize;
507 	/*
508 	 * Truncate size to a multiple of the page cache size or the default
509 	 * log page size if the page cache size is between the default log page
510 	 * log page size if the page cache size is between the default log page
511 	 * size and twice that.
512 	 */
513 	if (PAGE_SIZE >= DefaultLogPageSize && PAGE_SIZE <=
514 			DefaultLogPageSize * 2)
515 		log_page_size = DefaultLogPageSize;
516 	else
517 		log_page_size = PAGE_SIZE;
518 	log_page_mask = log_page_size - 1;
519 	/*
520 	 * Use ntfs_ffs() instead of ffs() to enable the compiler to
521 	 * optimize log_page_size and log_page_bits into constants.
522 	 */
523 	log_page_bits = ntfs_ffs(log_page_size) - 1;
524 	size &= ~(s64)(log_page_size - 1);
525 	/*
526 	 * Ensure the log file is big enough to store at least the two restart
527 	 * pages and the minimum number of log record pages.
528 	 */
529 	if (size < log_page_size * 2 || (size - log_page_size * 2) >>
530 			log_page_bits < MinLogRecordPages) {
531 		ntfs_error(vol->sb, "$LogFile is too small.");
532 		return false;
533 	}
534 	/*
535 	 * Read through the file looking for a restart page.  Since the restart
536 	 * page header is at the beginning of a page we only need to search at
537 	 * what could be the beginning of a page (for each page size) rather
538 	 * than scanning the whole file byte by byte.  If all potential places
539 	 * contain empty and uninitialzed records, the log file can be assumed
540 	 * to be empty.
541 	 */
542 	for (pos = 0; pos < size; pos <<= 1) {
543 		pgoff_t idx = pos >> PAGE_SHIFT;
544 		if (!page || page->index != idx) {
545 			if (page)
546 				ntfs_unmap_page(page);
547 			page = ntfs_map_page(mapping, idx);
548 			if (IS_ERR(page)) {
549 				ntfs_error(vol->sb, "Error mapping $LogFile "
550 						"page (index %lu).", idx);
551 				goto err_out;
552 			}
553 		}
554 		kaddr = (u8*)page_address(page) + (pos & ~PAGE_MASK);
555 		/*
556 		 * A non-empty block means the logfile is not empty while an
557 		 * empty block after a non-empty block has been encountered
558 		 * means we are done.
559 		 */
560 		if (!ntfs_is_empty_recordp((le32*)kaddr))
561 			logfile_is_empty = false;
562 		else if (!logfile_is_empty)
563 			break;
564 		/*
565 		 * A log record page means there cannot be a restart page after
566 		 * this so no need to continue searching.
567 		 */
568 		if (ntfs_is_rcrd_recordp((le32*)kaddr))
569 			break;
570 		/* If not a (modified by chkdsk) restart page, continue. */
571 		if (!ntfs_is_rstr_recordp((le32*)kaddr) &&
572 				!ntfs_is_chkd_recordp((le32*)kaddr)) {
573 			if (!pos)
574 				pos = NTFS_BLOCK_SIZE >> 1;
575 			continue;
576 		}
577 		/*
578 		 * Check the (modified by chkdsk) restart page for consistency
579 		 * and get a copy of the complete multi sector transfer
580 		 * deprotected restart page.
581 		 */
582 		err = ntfs_check_and_load_restart_page(log_vi,
583 				(RESTART_PAGE_HEADER*)kaddr, pos,
584 				!rstr1_ph ? &rstr1_ph : &rstr2_ph,
585 				!rstr1_ph ? &rstr1_lsn : &rstr2_lsn);
586 		if (!err) {
587 			/*
588 			 * If we have now found the first (modified by chkdsk)
589 			 * restart page, continue looking for the second one.
590 			 */
591 			if (!pos) {
592 				pos = NTFS_BLOCK_SIZE >> 1;
593 				continue;
594 			}
595 			/*
596 			 * We have now found the second (modified by chkdsk)
597 			 * restart page, so we can stop looking.
598 			 */
599 			break;
600 		}
601 		/*
602 		 * Error output already done inside the function.  Note, we do
603 		 * not abort if the restart page was invalid as we might still
604 		 * find a valid one further in the file.
605 		 */
606 		if (err != -EINVAL) {
607 			ntfs_unmap_page(page);
608 			goto err_out;
609 		}
610 		/* Continue looking. */
611 		if (!pos)
612 			pos = NTFS_BLOCK_SIZE >> 1;
613 	}
614 	if (page)
615 		ntfs_unmap_page(page);
616 	if (logfile_is_empty) {
617 		NVolSetLogFileEmpty(vol);
618 is_empty:
619 		ntfs_debug("Done.  ($LogFile is empty.)");
620 		return true;
621 	}
622 	if (!rstr1_ph) {
623 		BUG_ON(rstr2_ph);
624 		ntfs_error(vol->sb, "Did not find any restart pages in "
625 				"$LogFile and it was not empty.");
626 		return false;
627 	}
628 	/* If both restart pages were found, use the more recent one. */
629 	if (rstr2_ph) {
630 		/*
631 		 * If the second restart area is more recent, switch to it.
632 		 * Otherwise just throw it away.
633 		 */
634 		if (rstr2_lsn > rstr1_lsn) {
635 			ntfs_debug("Using second restart page as it is more "
636 					"recent.");
637 			ntfs_free(rstr1_ph);
638 			rstr1_ph = rstr2_ph;
639 			/* rstr1_lsn = rstr2_lsn; */
640 		} else {
641 			ntfs_debug("Using first restart page as it is more "
642 					"recent.");
643 			ntfs_free(rstr2_ph);
644 		}
645 		rstr2_ph = NULL;
646 	}
647 	/* All consistency checks passed. */
648 	if (rp)
649 		*rp = rstr1_ph;
650 	else
651 		ntfs_free(rstr1_ph);
652 	ntfs_debug("Done.");
653 	return true;
654 err_out:
655 	if (rstr1_ph)
656 		ntfs_free(rstr1_ph);
657 	return false;
658 }
659 
660 /**
661  * ntfs_is_logfile_clean - check in the journal if the volume is clean
662  * @log_vi:	struct inode of loaded journal $LogFile to check
663  * @rp:		copy of the current restart page
664  *
665  * Analyze the $LogFile journal and return 'true' if it indicates the volume was
666  * shutdown cleanly and 'false' if not.
667  *
668  * At present we only look at the two restart pages and ignore the log record
669  * pages.  This is a little bit crude in that there will be a very small number
670  * of cases where we think that a volume is dirty when in fact it is clean.
671  * This should only affect volumes that have not been shutdown cleanly but did
672  * not have any pending, non-check-pointed i/o, i.e. they were completely idle
673  * at least for the five seconds preceding the unclean shutdown.
674  *
675  * This function assumes that the $LogFile journal has already been consistency
676  * checked by a call to ntfs_check_logfile() and in particular if the $LogFile
677  * is empty this function requires that NVolLogFileEmpty() is true otherwise an
678  * empty volume will be reported as dirty.
679  */
ntfs_is_logfile_clean(struct inode * log_vi,const RESTART_PAGE_HEADER * rp)680 bool ntfs_is_logfile_clean(struct inode *log_vi, const RESTART_PAGE_HEADER *rp)
681 {
682 	ntfs_volume *vol = NTFS_SB(log_vi->i_sb);
683 	RESTART_AREA *ra;
684 
685 	ntfs_debug("Entering.");
686 	/* An empty $LogFile must have been clean before it got emptied. */
687 	if (NVolLogFileEmpty(vol)) {
688 		ntfs_debug("Done.  ($LogFile is empty.)");
689 		return true;
690 	}
691 	BUG_ON(!rp);
692 	if (!ntfs_is_rstr_record(rp->magic) &&
693 			!ntfs_is_chkd_record(rp->magic)) {
694 		ntfs_error(vol->sb, "Restart page buffer is invalid.  This is "
695 				"probably a bug in that the $LogFile should "
696 				"have been consistency checked before calling "
697 				"this function.");
698 		return false;
699 	}
700 	ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
701 	/*
702 	 * If the $LogFile has active clients, i.e. it is open, and we do not
703 	 * have the RESTART_VOLUME_IS_CLEAN bit set in the restart area flags,
704 	 * we assume there was an unclean shutdown.
705 	 */
706 	if (ra->client_in_use_list != LOGFILE_NO_CLIENT &&
707 			!(ra->flags & RESTART_VOLUME_IS_CLEAN)) {
708 		ntfs_debug("Done.  $LogFile indicates a dirty shutdown.");
709 		return false;
710 	}
711 	/* $LogFile indicates a clean shutdown. */
712 	ntfs_debug("Done.  $LogFile indicates a clean shutdown.");
713 	return true;
714 }
715 
716 /**
717  * ntfs_empty_logfile - empty the contents of the $LogFile journal
718  * @log_vi:	struct inode of loaded journal $LogFile to empty
719  *
720  * Empty the contents of the $LogFile journal @log_vi and return 'true' on
721  * success and 'false' on error.
722  *
723  * This function assumes that the $LogFile journal has already been consistency
724  * checked by a call to ntfs_check_logfile() and that ntfs_is_logfile_clean()
725  * has been used to ensure that the $LogFile is clean.
726  */
ntfs_empty_logfile(struct inode * log_vi)727 bool ntfs_empty_logfile(struct inode *log_vi)
728 {
729 	VCN vcn, end_vcn;
730 	ntfs_inode *log_ni = NTFS_I(log_vi);
731 	ntfs_volume *vol = log_ni->vol;
732 	struct super_block *sb = vol->sb;
733 	runlist_element *rl;
734 	unsigned long flags;
735 	unsigned block_size, block_size_bits;
736 	int err;
737 	bool should_wait = true;
738 
739 	ntfs_debug("Entering.");
740 	if (NVolLogFileEmpty(vol)) {
741 		ntfs_debug("Done.");
742 		return true;
743 	}
744 	/*
745 	 * We cannot use ntfs_attr_set() because we may be still in the middle
746 	 * of a mount operation.  Thus we do the emptying by hand by first
747 	 * zapping the page cache pages for the $LogFile/$DATA attribute and
748 	 * then emptying each of the buffers in each of the clusters specified
749 	 * by the runlist by hand.
750 	 */
751 	block_size = sb->s_blocksize;
752 	block_size_bits = sb->s_blocksize_bits;
753 	vcn = 0;
754 	read_lock_irqsave(&log_ni->size_lock, flags);
755 	end_vcn = (log_ni->initialized_size + vol->cluster_size_mask) >>
756 			vol->cluster_size_bits;
757 	read_unlock_irqrestore(&log_ni->size_lock, flags);
758 	truncate_inode_pages(log_vi->i_mapping, 0);
759 	down_write(&log_ni->runlist.lock);
760 	rl = log_ni->runlist.rl;
761 	if (unlikely(!rl || vcn < rl->vcn || !rl->length)) {
762 map_vcn:
763 		err = ntfs_map_runlist_nolock(log_ni, vcn, NULL);
764 		if (err) {
765 			ntfs_error(sb, "Failed to map runlist fragment (error "
766 					"%d).", -err);
767 			goto err;
768 		}
769 		rl = log_ni->runlist.rl;
770 		BUG_ON(!rl || vcn < rl->vcn || !rl->length);
771 	}
772 	/* Seek to the runlist element containing @vcn. */
773 	while (rl->length && vcn >= rl[1].vcn)
774 		rl++;
775 	do {
776 		LCN lcn;
777 		sector_t block, end_block;
778 		s64 len;
779 
780 		/*
781 		 * If this run is not mapped map it now and start again as the
782 		 * runlist will have been updated.
783 		 */
784 		lcn = rl->lcn;
785 		if (unlikely(lcn == LCN_RL_NOT_MAPPED)) {
786 			vcn = rl->vcn;
787 			goto map_vcn;
788 		}
789 		/* If this run is not valid abort with an error. */
790 		if (unlikely(!rl->length || lcn < LCN_HOLE))
791 			goto rl_err;
792 		/* Skip holes. */
793 		if (lcn == LCN_HOLE)
794 			continue;
795 		block = lcn << vol->cluster_size_bits >> block_size_bits;
796 		len = rl->length;
797 		if (rl[1].vcn > end_vcn)
798 			len = end_vcn - rl->vcn;
799 		end_block = (lcn + len) << vol->cluster_size_bits >>
800 				block_size_bits;
801 		/* Iterate over the blocks in the run and empty them. */
802 		do {
803 			struct buffer_head *bh;
804 
805 			/* Obtain the buffer, possibly not uptodate. */
806 			bh = sb_getblk(sb, block);
807 			BUG_ON(!bh);
808 			/* Setup buffer i/o submission. */
809 			lock_buffer(bh);
810 			bh->b_end_io = end_buffer_write_sync;
811 			get_bh(bh);
812 			/* Set the entire contents of the buffer to 0xff. */
813 			memset(bh->b_data, -1, block_size);
814 			if (!buffer_uptodate(bh))
815 				set_buffer_uptodate(bh);
816 			if (buffer_dirty(bh))
817 				clear_buffer_dirty(bh);
818 			/*
819 			 * Submit the buffer and wait for i/o to complete but
820 			 * only for the first buffer so we do not miss really
821 			 * serious i/o errors.  Once the first buffer has
822 			 * completed ignore errors afterwards as we can assume
823 			 * that if one buffer worked all of them will work.
824 			 */
825 			submit_bh(REQ_OP_WRITE, 0, bh);
826 			if (should_wait) {
827 				should_wait = false;
828 				wait_on_buffer(bh);
829 				if (unlikely(!buffer_uptodate(bh)))
830 					goto io_err;
831 			}
832 			brelse(bh);
833 		} while (++block < end_block);
834 	} while ((++rl)->vcn < end_vcn);
835 	up_write(&log_ni->runlist.lock);
836 	/*
837 	 * Zap the pages again just in case any got instantiated whilst we were
838 	 * emptying the blocks by hand.  FIXME: We may not have completed
839 	 * writing to all the buffer heads yet so this may happen too early.
840 	 * We really should use a kernel thread to do the emptying
841 	 * asynchronously and then we can also set the volume dirty and output
842 	 * an error message if emptying should fail.
843 	 */
844 	truncate_inode_pages(log_vi->i_mapping, 0);
845 	/* Set the flag so we do not have to do it again on remount. */
846 	NVolSetLogFileEmpty(vol);
847 	ntfs_debug("Done.");
848 	return true;
849 io_err:
850 	ntfs_error(sb, "Failed to write buffer.  Unmount and run chkdsk.");
851 	goto dirty_err;
852 rl_err:
853 	ntfs_error(sb, "Runlist is corrupt.  Unmount and run chkdsk.");
854 dirty_err:
855 	NVolSetErrors(vol);
856 	err = -EIO;
857 err:
858 	up_write(&log_ni->runlist.lock);
859 	ntfs_error(sb, "Failed to fill $LogFile with 0xff bytes (error %d).",
860 			-err);
861 	return false;
862 }
863 
864 #endif /* NTFS_RW */
865