summaryrefslogtreecommitdiff
path: root/fs/ext4/ext4_journal.c
blob: ba4a7bb713d2c4e2cfce80b702d37e8f720064f1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
/*
 * (C) Copyright 2011 - 2012 Samsung Electronics
 * EXT4 filesystem implementation in Uboot by
 * Uma Shankar <uma.shankar@samsung.com>
 * Manjunatha C Achar <a.manjunatha@samsung.com>
 *
 * Journal data structures and headers for Journaling feature of ext4
 * have been referred from JBD2 (Journaling Block device 2)
 * implementation in Linux Kernel.
 * Written by Stephen C. Tweedie <sct@redhat.com>
 *
 * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
 * This file is part of the Linux kernel and is made available under
 * the terms of the GNU General Public License, version 2, or at your
 * option, any later version, incorporated herein by reference.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <common.h>
#include <ext4fs.h>
#include <malloc.h>
#include <ext_common.h>
#include "ext4_common.h"

static struct revoke_blk_list *revk_blk_list;
static struct revoke_blk_list *prev_node;
static int first_node = true;

int gindex;
int gd_index;
int jrnl_blk_idx;
struct journal_log *journal_ptr[MAX_JOURNAL_ENTRIES];
struct dirty_blocks *dirty_block_ptr[MAX_JOURNAL_ENTRIES];

int ext4fs_init_journal(void)
{
	int i;
	char *temp = NULL;
	struct ext_filesystem *fs = get_fs();

	/* init globals */
	revk_blk_list = NULL;
	prev_node = NULL;
	gindex = 0;
	gd_index = 0;
	jrnl_blk_idx = 1;

	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
		journal_ptr[i] = zalloc(sizeof(struct journal_log));
		if (!journal_ptr[i])
			goto fail;
		dirty_block_ptr[i] = zalloc(sizeof(struct dirty_blocks));
		if (!dirty_block_ptr[i])
			goto fail;
		journal_ptr[i]->buf = NULL;
		journal_ptr[i]->blknr = -1;

		dirty_block_ptr[i]->buf = NULL;
		dirty_block_ptr[i]->blknr = -1;
	}

	if (fs->blksz == 4096) {
		temp = zalloc(fs->blksz);
		if (!temp)
			goto fail;
		journal_ptr[gindex]->buf = zalloc(fs->blksz);
		if (!journal_ptr[gindex]->buf)
			goto fail;
		ext4fs_devread(0, 0, fs->blksz, temp);
		memcpy(temp + SUPERBLOCK_SIZE, fs->sb, SUPERBLOCK_SIZE);
		memcpy(journal_ptr[gindex]->buf, temp, fs->blksz);
		journal_ptr[gindex++]->blknr = 0;
		free(temp);
	} else {
		journal_ptr[gindex]->buf = zalloc(fs->blksz);
		if (!journal_ptr[gindex]->buf)
			goto fail;
		memcpy(journal_ptr[gindex]->buf, fs->sb, SUPERBLOCK_SIZE);
		journal_ptr[gindex++]->blknr = 1;
	}

	/* Check the file system state using journal super block */
	if (ext4fs_check_journal_state(SCAN))
		goto fail;
	/* Check the file system state using journal super block */
	if (ext4fs_check_journal_state(RECOVER))
		goto fail;

	return 0;
fail:
	return -1;
}

void ext4fs_dump_metadata(void)
{
	struct ext_filesystem *fs = get_fs();
	int i;
	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
		if (dirty_block_ptr[i]->blknr == -1)
			break;
		put_ext4((uint64_t) ((uint64_t)dirty_block_ptr[i]->blknr *
				(uint64_t)fs->blksz), dirty_block_ptr[i]->buf,
								fs->blksz);
	}
}

void ext4fs_free_journal(void)
{
	int i;
	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
		if (dirty_block_ptr[i]->blknr == -1)
			break;
		if (dirty_block_ptr[i]->buf)
			free(dirty_block_ptr[i]->buf);
	}

	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
		if (journal_ptr[i]->blknr == -1)
			break;
		if (journal_ptr[i]->buf)
			free(journal_ptr[i]->buf);
	}

	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
		if (journal_ptr[i])
			free(journal_ptr[i]);
		if (dirty_block_ptr[i])
			free(dirty_block_ptr[i]);
	}
	gindex = 0;
	gd_index = 0;
	jrnl_blk_idx = 1;
}

int ext4fs_log_gdt(char *gd_table)
{
	struct ext_filesystem *fs = get_fs();
	short i;
	long int var = fs->gdtable_blkno;
	for (i = 0; i < fs->no_blk_pergdt; i++) {
		journal_ptr[gindex]->buf = zalloc(fs->blksz);
		if (!journal_ptr[gindex]->buf)
			return -ENOMEM;
		memcpy(journal_ptr[gindex]->buf, gd_table, fs->blksz);
		gd_table += fs->blksz;
		journal_ptr[gindex++]->blknr = var++;
	}

	return 0;
}

/*
 * This function stores the backup copy of meta data in RAM
 * journal_buffer -- Buffer containing meta data
 * blknr -- Block number on disk of the meta data buffer
 */
int ext4fs_log_journal(char *journal_buffer, long int blknr)
{
	struct ext_filesystem *fs = get_fs();
	short i;

	if (!journal_buffer) {
		printf("Invalid input arguments %s\n", __func__);
		return -EINVAL;
	}

	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
		if (journal_ptr[i]->blknr == -1)
			break;
		if (journal_ptr[i]->blknr == blknr)
			return 0;
	}

	journal_ptr[gindex]->buf = zalloc(fs->blksz);
	if (!journal_ptr[gindex]->buf)
		return -ENOMEM;

	memcpy(journal_ptr[gindex]->buf, journal_buffer, fs->blksz);
	journal_ptr[gindex++]->blknr = blknr;

	return 0;
}

/*
 * This function stores the modified meta data in RAM
 * metadata_buffer -- Buffer containing meta data
 * blknr -- Block number on disk of the meta data buffer
 */
int ext4fs_put_metadata(char *metadata_buffer, long int blknr)
{
	struct ext_filesystem *fs = get_fs();
	if (!metadata_buffer) {
		printf("Invalid input arguments %s\n", __func__);
		return -EINVAL;
	}
	dirty_block_ptr[gd_index]->buf = zalloc(fs->blksz);
	if (!dirty_block_ptr[gd_index]->buf)
		return -ENOMEM;
	memcpy(dirty_block_ptr[gd_index]->buf, metadata_buffer, fs->blksz);
	dirty_block_ptr[gd_index++]->blknr = blknr;

	return 0;
}

void print_revoke_blks(char *revk_blk)
{
	int offset;
	int max;
	long int blocknr;
	struct journal_revoke_header_t *header;

	if (revk_blk == NULL)
		return;

	header = (struct journal_revoke_header_t *) revk_blk;
	offset = sizeof(struct journal_revoke_header_t);
	max = be32_to_cpu(header->r_count);
	printf("total bytes %d\n", max);

	while (offset < max) {
		blocknr = be32_to_cpu(*((long int *)(revk_blk + offset)));
		printf("revoke blknr is %ld\n", blocknr);
		offset += 4;
	}
}

static struct revoke_blk_list *_get_node(void)
{
	struct revoke_blk_list *tmp_node;
	tmp_node = zalloc(sizeof(struct revoke_blk_list));
	if (tmp_node == NULL)
		return NULL;
	tmp_node->content = NULL;
	tmp_node->next = NULL;

	return tmp_node;
}

void ext4fs_push_revoke_blk(char *buffer)
{
	struct revoke_blk_list *node = NULL;
	struct ext_filesystem *fs = get_fs();
	if (buffer == NULL) {
		printf("buffer ptr is NULL\n");
		return;
	}
	node = _get_node();
	if (!node) {
		printf("_get_node: malloc failed\n");
		return;
	}

	node->content = zalloc(fs->blksz);
	if (node->content == NULL)
		return;
	memcpy(node->content, buffer, fs->blksz);

	if (first_node == true) {
		revk_blk_list = node;
		prev_node = node;
		 first_node = false;
	} else {
		prev_node->next = node;
		prev_node = node;
	}
}

void ext4fs_free_revoke_blks(void)
{
	struct revoke_blk_list *tmp_node = revk_blk_list;
	struct revoke_blk_list *next_node = NULL;

	while (tmp_node != NULL) {
		if (tmp_node->content)
			free(tmp_node->content);
		tmp_node = tmp_node->next;
	}

	tmp_node = revk_blk_list;
	while (tmp_node != NULL) {
		next_node = tmp_node->next;
		free(tmp_node);
		tmp_node = next_node;
	}

	revk_blk_list = NULL;
	prev_node = NULL;
	first_node = true;
}

int check_blknr_for_revoke(long int blknr, int sequence_no)
{
	struct journal_revoke_header_t *header;
	int offset;
	int max;
	long int blocknr;
	char *revk_blk;
	struct revoke_blk_list *tmp_revk_node = revk_blk_list;
	while (tmp_revk_node != NULL) {
		revk_blk = tmp_revk_node->content;

		header = (struct journal_revoke_header_t *) revk_blk;
		if (sequence_no < be32_to_cpu(header->r_header.h_sequence)) {
			offset = sizeof(struct journal_revoke_header_t);
			max = be32_to_cpu(header->r_count);

			while (offset < max) {
				blocknr = be32_to_cpu(*((long int *)
						  (revk_blk + offset)));
				if (blocknr == blknr)
					goto found;
				offset += 4;
			}
		}
		tmp_revk_node = tmp_revk_node->next;
	}

	return -1;

found:
	return 0;
}

/*
 * This function parses the journal blocks and replays the
 * suceessful transactions. A transaction is successfull
 * if commit block is found for a descriptor block
 * The tags in descriptor block contain the disk block
 * numbers of the metadata  to be replayed
 */
void recover_transaction(int prev_desc_logical_no)
{
	struct ext2_inode inode_journal;
	struct ext_filesystem *fs = get_fs();
	struct journal_header_t *jdb;
	long int blknr;
	char *p_jdb;
	int ofs, flags;
	int i;
	struct ext3_journal_block_tag *tag;
	char *temp_buff = zalloc(fs->blksz);
	char *metadata_buff = zalloc(fs->blksz);
	if (!temp_buff || !metadata_buff)
		goto fail;
	i = prev_desc_logical_no;
	ext4fs_read_inode(ext4fs_root, EXT2_JOURNAL_INO,
			  (struct ext2_inode *)&inode_journal);
	blknr = read_allocated_block((struct ext2_inode *)
				     &inode_journal, i);
	ext4fs_devread(blknr * fs->sect_perblk, 0, fs->blksz, temp_buff);
	p_jdb = (char *)temp_buff;
	jdb = (struct journal_header_t *) temp_buff;
	ofs = sizeof(struct journal_header_t);

	do {
		tag = (struct ext3_journal_block_tag *)&p_jdb[ofs];
		ofs += sizeof(struct ext3_journal_block_tag);

		if (ofs > fs->blksz)
			break;

		flags = be32_to_cpu(tag->flags);
		if (!(flags & EXT3_JOURNAL_FLAG_SAME_UUID))
			ofs += 16;

		i++;
		debug("\t\ttag %u\n", be32_to_cpu(tag->block));
		if (revk_blk_list != NULL) {
			if (check_blknr_for_revoke(be32_to_cpu(tag->block),
				be32_to_cpu(jdb->h_sequence)) == 0)
				continue;
		}
		blknr = read_allocated_block(&inode_journal, i);
		ext4fs_devread(blknr * fs->sect_perblk, 0,
			       fs->blksz, metadata_buff);
		put_ext4((uint64_t)(be32_to_cpu(tag->block) * fs->blksz),
			 metadata_buff, (uint32_t) fs->blksz);
	} while (!(flags & EXT3_JOURNAL_FLAG_LAST_TAG));
fail:
	free(temp_buff);
	free(metadata_buff);
}

void print_jrnl_status(int recovery_flag)
{
	if (recovery_flag == RECOVER)
		printf("Journal Recovery Completed\n");
	else
		printf("Journal Scan Completed\n");
}

int ext4fs_check_journal_state(int recovery_flag)
{
	int i;
	int DB_FOUND = NO;
	long int blknr;
	int transaction_state = TRANSACTION_COMPLETE;
	int prev_desc_logical_no = 0;
	int curr_desc_logical_no = 0;
	int ofs, flags;
	struct ext2_inode inode_journal;
	struct journal_superblock_t *jsb = NULL;
	struct journal_header_t *jdb = NULL;
	char *p_jdb = NULL;
	struct ext3_journal_block_tag *tag = NULL;
	char *temp_buff = NULL;
	char *temp_buff1 = NULL;
	struct ext_filesystem *fs = get_fs();

	temp_buff = zalloc(fs->blksz);
	if (!temp_buff)
		return -ENOMEM;
	temp_buff1 = zalloc(fs->blksz);
	if (!temp_buff1) {
		free(temp_buff);
		return -ENOMEM;
	}

	ext4fs_read_inode(ext4fs_root, EXT2_JOURNAL_INO, &inode_journal);
	blknr = read_allocated_block(&inode_journal, EXT2_JOURNAL_SUPERBLOCK);
	ext4fs_devread(blknr * fs->sect_perblk, 0, fs->blksz, temp_buff);
	jsb = (struct journal_superblock_t *) temp_buff;

	if (fs->sb->feature_incompat & EXT3_FEATURE_INCOMPAT_RECOVER) {
		if (recovery_flag == RECOVER)
			printf("Recovery required\n");
	} else {
		if (recovery_flag == RECOVER)
			printf("File System is consistent\n");
		goto end;
	}

	if (be32_to_cpu(jsb->s_start) == 0)
		goto end;

	if (!(jsb->s_feature_compat &
				cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM)))
		jsb->s_feature_compat |=
				cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);

	i = be32_to_cpu(jsb->s_first);
	while (1) {
		blknr = read_allocated_block(&inode_journal, i);
		memset(temp_buff1, '\0', fs->blksz);
		ext4fs_devread(blknr * fs->sect_perblk,
			       0, fs->blksz, temp_buff1);
		jdb = (struct journal_header_t *) temp_buff1;

		if (be32_to_cpu(jdb->h_blocktype) ==
		    EXT3_JOURNAL_DESCRIPTOR_BLOCK) {
			if (be32_to_cpu(jdb->h_sequence) !=
			    be32_to_cpu(jsb->s_sequence)) {
				print_jrnl_status(recovery_flag);
				break;
			}

			curr_desc_logical_no = i;
			if (transaction_state == TRANSACTION_COMPLETE)
				transaction_state = TRANSACTION_RUNNING;
			else
				return -1;
			p_jdb = (char *)temp_buff1;
			ofs = sizeof(struct journal_header_t);
			do {
				tag = (struct ext3_journal_block_tag *)
				    &p_jdb[ofs];
				ofs += sizeof(struct ext3_journal_block_tag);
				if (ofs > fs->blksz)
					break;
				flags = be32_to_cpu(tag->flags);
				if (!(flags & EXT3_JOURNAL_FLAG_SAME_UUID))
					ofs += 16;
				i++;
				debug("\t\ttag %u\n", be32_to_cpu(tag->block));
			} while (!(flags & EXT3_JOURNAL_FLAG_LAST_TAG));
			i++;
			DB_FOUND = YES;
		} else if (be32_to_cpu(jdb->h_blocktype) ==
				EXT3_JOURNAL_COMMIT_BLOCK) {
			if (be32_to_cpu(jdb->h_sequence) !=
			     be32_to_cpu(jsb->s_sequence)) {
				print_jrnl_status(recovery_flag);
				break;
			}

			if (transaction_state == TRANSACTION_RUNNING ||
					(DB_FOUND == NO)) {
				transaction_state = TRANSACTION_COMPLETE;
				i++;
				jsb->s_sequence =
					cpu_to_be32(be32_to_cpu(
						jsb->s_sequence) + 1);
			}
			prev_desc_logical_no = curr_desc_logical_no;
			if ((recovery_flag == RECOVER) && (DB_FOUND == YES))
				recover_transaction(prev_desc_logical_no);

			DB_FOUND = NO;
		} else if (be32_to_cpu(jdb->h_blocktype) ==
				EXT3_JOURNAL_REVOKE_BLOCK) {
			if (be32_to_cpu(jdb->h_sequence) !=
			    be32_to_cpu(jsb->s_sequence)) {
				print_jrnl_status(recovery_flag);
				break;
			}
			if (recovery_flag == SCAN)
				ext4fs_push_revoke_blk((char *)jdb);
			i++;
		} else {
			debug("Else Case\n");
			if (be32_to_cpu(jdb->h_sequence) !=
			    be32_to_cpu(jsb->s_sequence)) {
				print_jrnl_status(recovery_flag);
				break;
			}
		}
	}

end:
	if (recovery_flag == RECOVER) {
		jsb->s_start = cpu_to_be32(1);
		jsb->s_sequence = cpu_to_be32(be32_to_cpu(jsb->s_sequence) + 1);
		/* get the superblock */
		ext4fs_devread(SUPERBLOCK_SECTOR, 0, SUPERBLOCK_SIZE,
			       (char *)fs->sb);
		fs->sb->feature_incompat |= EXT3_FEATURE_INCOMPAT_RECOVER;

		/* Update the super block */
		put_ext4((uint64_t) (SUPERBLOCK_SIZE),
			 (struct ext2_sblock *)fs->sb,
			 (uint32_t) SUPERBLOCK_SIZE);
		ext4fs_devread(SUPERBLOCK_SECTOR, 0, SUPERBLOCK_SIZE,
			       (char *)fs->sb);

		blknr = read_allocated_block(&inode_journal,
					 EXT2_JOURNAL_SUPERBLOCK);
		put_ext4((uint64_t) (blknr * fs->blksz),
			 (struct journal_superblock_t *)temp_buff,
			 (uint32_t) fs->blksz);
		ext4fs_free_revoke_blks();
	}
	free(temp_buff);
	free(temp_buff1);

	return 0;
}

static void update_descriptor_block(long int blknr)
{
	int i;
	long int jsb_blknr;
	struct journal_header_t jdb;
	struct ext3_journal_block_tag tag;
	struct ext2_inode inode_journal;
	struct journal_superblock_t *jsb = NULL;
	char *buf = NULL;
	char *temp = NULL;
	struct ext_filesystem *fs = get_fs();
	char *temp_buff = zalloc(fs->blksz);
	if (!temp_buff)
		return;

	ext4fs_read_inode(ext4fs_root, EXT2_JOURNAL_INO, &inode_journal);
	jsb_blknr = read_allocated_block(&inode_journal,
					 EXT2_JOURNAL_SUPERBLOCK);
	ext4fs_devread(jsb_blknr * fs->sect_perblk, 0, fs->blksz, temp_buff);
	jsb = (struct journal_superblock_t *) temp_buff;

	jdb.h_blocktype = cpu_to_be32(EXT3_JOURNAL_DESCRIPTOR_BLOCK);
	jdb.h_magic = cpu_to_be32(EXT3_JOURNAL_MAGIC_NUMBER);
	jdb.h_sequence = jsb->s_sequence;
	buf = zalloc(fs->blksz);
	if (!buf) {
		free(temp_buff);
		return;
	}
	temp = buf;
	memcpy(buf, &jdb, sizeof(struct journal_header_t));
	temp += sizeof(struct journal_header_t);

	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
		if (journal_ptr[i]->blknr == -1)
			break;

		tag.block = cpu_to_be32(journal_ptr[i]->blknr);
		tag.flags = cpu_to_be32(EXT3_JOURNAL_FLAG_SAME_UUID);
		memcpy(temp, &tag, sizeof(struct ext3_journal_block_tag));
		temp = temp + sizeof(struct ext3_journal_block_tag);
	}

	tag.block = cpu_to_be32(journal_ptr[--i]->blknr);
	tag.flags = cpu_to_be32(EXT3_JOURNAL_FLAG_LAST_TAG);
	memcpy(temp - sizeof(struct ext3_journal_block_tag), &tag,
	       sizeof(struct ext3_journal_block_tag));
	put_ext4((uint64_t) (blknr * fs->blksz), buf, (uint32_t) fs->blksz);

	free(temp_buff);
	free(buf);
}

static void update_commit_block(long int blknr)
{
	struct journal_header_t jdb;
	struct ext_filesystem *fs = get_fs();
	char *buf = NULL;
	struct ext2_inode inode_journal;
	struct journal_superblock_t *jsb;
	long int jsb_blknr;
	char *temp_buff = zalloc(fs->blksz);
	if (!temp_buff)
		return;

	ext4fs_read_inode(ext4fs_root, EXT2_JOURNAL_INO, &inode_journal);
	jsb_blknr = read_allocated_block(&inode_journal,
					 EXT2_JOURNAL_SUPERBLOCK);
	ext4fs_devread(jsb_blknr * fs->sect_perblk, 0, fs->blksz, temp_buff);
	jsb = (struct journal_superblock_t *) temp_buff;

	jdb.h_blocktype = cpu_to_be32(EXT3_JOURNAL_COMMIT_BLOCK);
	jdb.h_magic = cpu_to_be32(EXT3_JOURNAL_MAGIC_NUMBER);
	jdb.h_sequence = jsb->s_sequence;
	buf = zalloc(fs->blksz);
	if (!buf) {
		free(temp_buff);
		return;
	}
	memcpy(buf, &jdb, sizeof(struct journal_header_t));
	put_ext4((uint64_t) (blknr * fs->blksz), buf, (uint32_t) fs->blksz);

	free(temp_buff);
	free(buf);
}

void ext4fs_update_journal(void)
{
	struct ext2_inode inode_journal;
	struct ext_filesystem *fs = get_fs();
	long int blknr;
	int i;
	ext4fs_read_inode(ext4fs_root, EXT2_JOURNAL_INO, &inode_journal);
	blknr = read_allocated_block(&inode_journal, jrnl_blk_idx++);
	update_descriptor_block(blknr);
	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
		if (journal_ptr[i]->blknr == -1)
			break;
		blknr = read_allocated_block(&inode_journal, jrnl_blk_idx++);
		put_ext4((uint64_t) ((uint64_t)blknr * (uint64_t)fs->blksz),
			 journal_ptr[i]->buf, fs->blksz);
	}
	blknr = read_allocated_block(&inode_journal, jrnl_blk_idx++);
	update_commit_block(blknr);
	printf("update journal finished\n");
}