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      1 /*
      2  * journal.c --- code for handling the "ext3" journal
      3  *
      4  * Copyright (C) 2000 Andreas Dilger
      5  * Copyright (C) 2000 Theodore Ts'o
      6  *
      7  * Parts of the code are based on fs/jfs/journal.c by Stephen C. Tweedie
      8  * Copyright (C) 1999 Red Hat Software
      9  *
     10  * This file may be redistributed under the terms of the
     11  * GNU General Public License version 2 or at your discretion
     12  * any later version.
     13  */
     14 
     15 #include "config.h"
     16 #ifdef HAVE_SYS_MOUNT_H
     17 #include <sys/param.h>
     18 #include <sys/mount.h>
     19 #define MNT_FL (MS_MGC_VAL | MS_RDONLY)
     20 #endif
     21 #ifdef HAVE_SYS_STAT_H
     22 #include <sys/stat.h>
     23 #endif
     24 
     25 #define E2FSCK_INCLUDE_INLINE_FUNCS
     26 #include "uuid/uuid.h"
     27 #include "journal.h"
     28 
     29 #ifdef CONFIG_JBD_DEBUG		/* Enabled by configure --enable-jfs-debug */
     30 static int bh_count = 0;
     31 #endif
     32 
     33 #if EXT2_FLAT_INCLUDES
     34 #include "blkid.h"
     35 #else
     36 #include "blkid/blkid.h"
     37 #endif
     38 
     39 /*
     40  * Define USE_INODE_IO to use the inode_io.c / fileio.c codepaths.
     41  * This creates a larger static binary, and a smaller binary using
     42  * shared libraries.  It's also probably slightly less CPU-efficient,
     43  * which is why it's not on by default.  But, it's a good way of
     44  * testing the functions in inode_io.c and fileio.c.
     45  */
     46 #undef USE_INODE_IO
     47 
     48 /* Checksumming functions */
     49 static int ext2fs_journal_verify_csum_type(journal_t *j,
     50 					   journal_superblock_t *jsb)
     51 {
     52 	if (!journal_has_csum_v2or3(j))
     53 		return 1;
     54 
     55 	return jsb->s_checksum_type == JBD2_CRC32C_CHKSUM;
     56 }
     57 
     58 static __u32 ext2fs_journal_sb_csum(journal_superblock_t *jsb)
     59 {
     60 	__u32 crc, old_crc;
     61 
     62 	old_crc = jsb->s_checksum;
     63 	jsb->s_checksum = 0;
     64 	crc = ext2fs_crc32c_le(~0, (unsigned char *)jsb,
     65 			       sizeof(journal_superblock_t));
     66 	jsb->s_checksum = old_crc;
     67 
     68 	return crc;
     69 }
     70 
     71 static int ext2fs_journal_sb_csum_verify(journal_t *j,
     72 					 journal_superblock_t *jsb)
     73 {
     74 	__u32 provided, calculated;
     75 
     76 	if (!journal_has_csum_v2or3(j))
     77 		return 1;
     78 
     79 	provided = ext2fs_be32_to_cpu(jsb->s_checksum);
     80 	calculated = ext2fs_journal_sb_csum(jsb);
     81 
     82 	return provided == calculated;
     83 }
     84 
     85 static errcode_t ext2fs_journal_sb_csum_set(journal_t *j,
     86 					    journal_superblock_t *jsb)
     87 {
     88 	__u32 crc;
     89 
     90 	if (!journal_has_csum_v2or3(j))
     91 		return 0;
     92 
     93 	crc = ext2fs_journal_sb_csum(jsb);
     94 	jsb->s_checksum = ext2fs_cpu_to_be32(crc);
     95 	return 0;
     96 }
     97 
     98 /* Kernel compatibility functions for handling the journal.  These allow us
     99  * to use the recovery.c file virtually unchanged from the kernel, so we
    100  * don't have to do much to keep kernel and user recovery in sync.
    101  */
    102 int journal_bmap(journal_t *journal, blk64_t block, unsigned long long *phys)
    103 {
    104 #ifdef USE_INODE_IO
    105 	*phys = block;
    106 	return 0;
    107 #else
    108 	struct inode	*inode = journal->j_inode;
    109 	errcode_t	retval;
    110 	blk64_t		pblk;
    111 
    112 	if (!inode) {
    113 		*phys = block;
    114 		return 0;
    115 	}
    116 
    117 	retval = ext2fs_bmap2(inode->i_fs, inode->i_ino,
    118 			      &inode->i_ext2, NULL, 0, block, 0, &pblk);
    119 	*phys = pblk;
    120 	return (int) retval;
    121 #endif
    122 }
    123 
    124 struct buffer_head *getblk(kdev_t kdev, blk64_t blocknr, int blocksize)
    125 {
    126 	struct buffer_head *bh;
    127 	int bufsize = sizeof(*bh) + kdev->k_fs->blocksize -
    128 		sizeof(bh->b_data);
    129 	errcode_t retval;
    130 
    131 	retval = ext2fs_get_memzero(bufsize, &bh);
    132 	if (retval)
    133 		return NULL;
    134 
    135 #ifdef CONFIG_JBD_DEBUG
    136 	if (journal_enable_debug >= 3)
    137 		bh_count++;
    138 #endif
    139 	jfs_debug(4, "getblk for block %llu (%d bytes)(total %d)\n",
    140 		  (unsigned long long) blocknr, blocksize, bh_count);
    141 
    142 	bh->b_fs = kdev->k_fs;
    143 	if (kdev->k_dev == K_DEV_FS)
    144 		bh->b_io = kdev->k_fs->io;
    145 	else
    146 		bh->b_io = kdev->k_fs->journal_io;
    147 	bh->b_size = blocksize;
    148 	bh->b_blocknr = blocknr;
    149 
    150 	return bh;
    151 }
    152 
    153 int sync_blockdev(kdev_t kdev)
    154 {
    155 	io_channel	io;
    156 
    157 	if (kdev->k_dev == K_DEV_FS)
    158 		io = kdev->k_fs->io;
    159 	else
    160 		io = kdev->k_fs->journal_io;
    161 
    162 	return io_channel_flush(io) ? EIO : 0;
    163 }
    164 
    165 void ll_rw_block(int rw, int nr, struct buffer_head *bhp[])
    166 {
    167 	errcode_t retval;
    168 	struct buffer_head *bh;
    169 
    170 	for (; nr > 0; --nr) {
    171 		bh = *bhp++;
    172 		if (rw == READ && !bh->b_uptodate) {
    173 			jfs_debug(3, "reading block %llu/%p\n",
    174 				  bh->b_blocknr, (void *) bh);
    175 			retval = io_channel_read_blk64(bh->b_io,
    176 						     bh->b_blocknr,
    177 						     1, bh->b_data);
    178 			if (retval) {
    179 				com_err(bh->b_fs->device_name, retval,
    180 					"while reading block %llu\n",
    181 					bh->b_blocknr);
    182 				bh->b_err = (int) retval;
    183 				continue;
    184 			}
    185 			bh->b_uptodate = 1;
    186 		} else if (rw == WRITE && bh->b_dirty) {
    187 			jfs_debug(3, "writing block %llu/%p\n",
    188 				  bh->b_blocknr,
    189 				  (void *) bh);
    190 			retval = io_channel_write_blk64(bh->b_io,
    191 						      bh->b_blocknr,
    192 						      1, bh->b_data);
    193 			if (retval) {
    194 				com_err(bh->b_fs->device_name, retval,
    195 					"while writing block %llu\n",
    196 					bh->b_blocknr);
    197 				bh->b_err = (int) retval;
    198 				continue;
    199 			}
    200 			bh->b_dirty = 0;
    201 			bh->b_uptodate = 1;
    202 		} else {
    203 			jfs_debug(3, "no-op %s for block %llu\n",
    204 				  rw == READ ? "read" : "write",
    205 				  bh->b_blocknr);
    206 		}
    207 	}
    208 }
    209 
    210 void mark_buffer_dirty(struct buffer_head *bh)
    211 {
    212 	bh->b_dirty = 1;
    213 }
    214 
    215 static void mark_buffer_clean(struct buffer_head *bh)
    216 {
    217 	bh->b_dirty = 0;
    218 }
    219 
    220 void brelse(struct buffer_head *bh)
    221 {
    222 	if (bh->b_dirty)
    223 		ll_rw_block(WRITE, 1, &bh);
    224 	jfs_debug(3, "freeing block %llu/%p (total %d)\n",
    225 		  bh->b_blocknr, (void *) bh, --bh_count);
    226 	ext2fs_free_mem(&bh);
    227 }
    228 
    229 int buffer_uptodate(struct buffer_head *bh)
    230 {
    231 	return bh->b_uptodate;
    232 }
    233 
    234 void mark_buffer_uptodate(struct buffer_head *bh, int val)
    235 {
    236 	bh->b_uptodate = val;
    237 }
    238 
    239 void wait_on_buffer(struct buffer_head *bh)
    240 {
    241 	if (!bh->b_uptodate)
    242 		ll_rw_block(READ, 1, &bh);
    243 }
    244 
    245 
    246 static void ext2fs_clear_recover(ext2_filsys fs, int error)
    247 {
    248 	ext2fs_clear_feature_journal_needs_recovery(fs->super);
    249 
    250 	/* if we had an error doing journal recovery, we need a full fsck */
    251 	if (error)
    252 		fs->super->s_state &= ~EXT2_VALID_FS;
    253 	/*
    254 	 * If we replayed the journal by definition the file system
    255 	 * was mounted since the last time it was checked
    256 	 */
    257 	if (fs->super->s_lastcheck >= fs->super->s_mtime)
    258 		fs->super->s_lastcheck = fs->super->s_mtime - 1;
    259 	ext2fs_mark_super_dirty(fs);
    260 }
    261 
    262 /*
    263  * This is a helper function to check the validity of the journal.
    264  */
    265 struct process_block_struct {
    266 	e2_blkcnt_t	last_block;
    267 };
    268 
    269 static int process_journal_block(ext2_filsys fs,
    270 				 blk64_t	*block_nr,
    271 				 e2_blkcnt_t blockcnt,
    272 				 blk64_t ref_block EXT2FS_ATTR((unused)),
    273 				 int ref_offset EXT2FS_ATTR((unused)),
    274 				 void *priv_data)
    275 {
    276 	struct process_block_struct *p;
    277 	blk64_t	blk = *block_nr;
    278 
    279 	p = (struct process_block_struct *) priv_data;
    280 
    281 	if (!blk || blk < fs->super->s_first_data_block ||
    282 	    blk >= ext2fs_blocks_count(fs->super))
    283 		return BLOCK_ABORT;
    284 
    285 	if (blockcnt >= 0)
    286 		p->last_block = blockcnt;
    287 	return 0;
    288 }
    289 
    290 static errcode_t ext2fs_get_journal(ext2_filsys fs, journal_t **ret_journal)
    291 {
    292 	struct process_block_struct pb;
    293 	struct ext2_super_block *sb = fs->super;
    294 	struct ext2_super_block jsuper;
    295 	struct buffer_head	*bh;
    296 	struct inode		*j_inode = NULL;
    297 	struct kdev_s		*dev_fs = NULL, *dev_journal;
    298 	const char		*journal_name = 0;
    299 	journal_t		*journal = NULL;
    300 	errcode_t		retval = 0;
    301 	io_manager		io_ptr = 0;
    302 	unsigned long long	start = 0;
    303 	int			ext_journal = 0;
    304 	int			tried_backup_jnl = 0;
    305 
    306 	retval = ext2fs_get_memzero(sizeof(journal_t), &journal);
    307 	if (retval)
    308 		return retval;
    309 
    310 	retval = ext2fs_get_memzero(2 * sizeof(struct kdev_s), &dev_fs);
    311 	if (retval)
    312 		goto errout;
    313 	dev_journal = dev_fs+1;
    314 
    315 	dev_fs->k_fs = dev_journal->k_fs = fs;
    316 	dev_fs->k_dev = K_DEV_FS;
    317 	dev_journal->k_dev = K_DEV_JOURNAL;
    318 
    319 	journal->j_dev = dev_journal;
    320 	journal->j_fs_dev = dev_fs;
    321 	journal->j_inode = NULL;
    322 	journal->j_blocksize = fs->blocksize;
    323 
    324 	if (uuid_is_null(sb->s_journal_uuid)) {
    325 		if (!sb->s_journal_inum) {
    326 			retval = EXT2_ET_BAD_INODE_NUM;
    327 			goto errout;
    328 		}
    329 		retval = ext2fs_get_memzero(sizeof(*j_inode), &j_inode);
    330 		if (retval)
    331 			goto errout;
    332 
    333 		j_inode->i_fs = fs;
    334 		j_inode->i_ino = sb->s_journal_inum;
    335 
    336 		retval = ext2fs_read_inode(fs, sb->s_journal_inum,
    337 					   &j_inode->i_ext2);
    338 		if (retval) {
    339 try_backup_journal:
    340 			if (sb->s_jnl_backup_type != EXT3_JNL_BACKUP_BLOCKS ||
    341 			    tried_backup_jnl)
    342 				goto errout;
    343 			memset(&j_inode->i_ext2, 0, sizeof(struct ext2_inode));
    344 			memcpy(&j_inode->i_ext2.i_block[0], sb->s_jnl_blocks,
    345 			       EXT2_N_BLOCKS*4);
    346 			j_inode->i_ext2.i_size_high = sb->s_jnl_blocks[15];
    347 			j_inode->i_ext2.i_size = sb->s_jnl_blocks[16];
    348 			j_inode->i_ext2.i_links_count = 1;
    349 			j_inode->i_ext2.i_mode = LINUX_S_IFREG | 0600;
    350 			tried_backup_jnl++;
    351 		}
    352 		if (!j_inode->i_ext2.i_links_count ||
    353 		    !LINUX_S_ISREG(j_inode->i_ext2.i_mode)) {
    354 			retval = EXT2_ET_NO_JOURNAL;
    355 			goto try_backup_journal;
    356 		}
    357 		if (EXT2_I_SIZE(&j_inode->i_ext2) / journal->j_blocksize <
    358 		    JFS_MIN_JOURNAL_BLOCKS) {
    359 			retval = EXT2_ET_JOURNAL_TOO_SMALL;
    360 			goto try_backup_journal;
    361 		}
    362 		pb.last_block = -1;
    363 		retval = ext2fs_block_iterate3(fs, j_inode->i_ino,
    364 					       BLOCK_FLAG_HOLE, 0,
    365 					       process_journal_block, &pb);
    366 		if ((pb.last_block + 1) * fs->blocksize <
    367 		    (int) EXT2_I_SIZE(&j_inode->i_ext2)) {
    368 			retval = EXT2_ET_JOURNAL_TOO_SMALL;
    369 			goto try_backup_journal;
    370 		}
    371 		if (tried_backup_jnl && (fs->flags & EXT2_FLAG_RW)) {
    372 			retval = ext2fs_write_inode(fs, sb->s_journal_inum,
    373 						    &j_inode->i_ext2);
    374 			if (retval)
    375 				goto errout;
    376 		}
    377 
    378 		journal->j_maxlen = EXT2_I_SIZE(&j_inode->i_ext2) /
    379 			journal->j_blocksize;
    380 
    381 #ifdef USE_INODE_IO
    382 		retval = ext2fs_inode_io_intern2(fs, sb->s_journal_inum,
    383 						 &j_inode->i_ext2,
    384 						 &journal_name);
    385 		if (retval)
    386 			goto errout;
    387 
    388 		io_ptr = inode_io_manager;
    389 #else
    390 		journal->j_inode = j_inode;
    391 		fs->journal_io = fs->io;
    392 		retval = (errcode_t)journal_bmap(journal, 0, &start);
    393 		if (retval)
    394 			goto errout;
    395 #endif
    396 	} else {
    397 		ext_journal = 1;
    398 		if (!fs->journal_name) {
    399 			char uuid[37];
    400 			blkid_cache blkid;
    401 
    402 			blkid_get_cache(&blkid, NULL);
    403 			uuid_unparse(sb->s_journal_uuid, uuid);
    404 			fs->journal_name = blkid_get_devname(blkid,
    405 							      "UUID", uuid);
    406 			if (!fs->journal_name)
    407 				fs->journal_name = blkid_devno_to_devname(sb->s_journal_dev);
    408 			blkid_put_cache(blkid);
    409 		}
    410 		journal_name = fs->journal_name;
    411 
    412 		if (!journal_name) {
    413 			retval = EXT2_ET_LOAD_EXT_JOURNAL;
    414 			goto errout;
    415 		}
    416 
    417 		jfs_debug(1, "Using journal file %s\n", journal_name);
    418 		io_ptr = unix_io_manager;
    419 	}
    420 
    421 #if 0
    422 	test_io_backing_manager = io_ptr;
    423 	io_ptr = test_io_manager;
    424 #endif
    425 #ifndef USE_INODE_IO
    426 	if (ext_journal)
    427 #endif
    428 	{
    429 		retval = io_ptr->open(journal_name, fs->flags & EXT2_FLAG_RW,
    430 				      &fs->journal_io);
    431 	}
    432 	if (retval)
    433 		goto errout;
    434 
    435 	io_channel_set_blksize(fs->journal_io, fs->blocksize);
    436 
    437 	if (ext_journal) {
    438 		blk64_t maxlen;
    439 
    440 		start = ext2fs_journal_sb_start(fs->blocksize) - 1;
    441 		bh = getblk(dev_journal, start, fs->blocksize);
    442 		if (!bh) {
    443 			retval = EXT2_ET_NO_MEMORY;
    444 			goto errout;
    445 		}
    446 		ll_rw_block(READ, 1, &bh);
    447 		retval = bh->b_err;
    448 		if (retval) {
    449 			brelse(bh);
    450 			goto errout;
    451 		}
    452 		memcpy(&jsuper, start ? bh->b_data :
    453 				bh->b_data + SUPERBLOCK_OFFSET,
    454 		       sizeof(jsuper));
    455 #ifdef WORDS_BIGENDIAN
    456 		if (jsuper.s_magic == ext2fs_swab16(EXT2_SUPER_MAGIC))
    457 			ext2fs_swap_super(&jsuper);
    458 #endif
    459 		if (jsuper.s_magic != EXT2_SUPER_MAGIC ||
    460 		    !ext2fs_has_feature_journal_dev(&jsuper)) {
    461 			retval = EXT2_ET_LOAD_EXT_JOURNAL;
    462 			brelse(bh);
    463 			goto errout;
    464 		}
    465 		/* Make sure the journal UUID is correct */
    466 		if (memcmp(jsuper.s_uuid, fs->super->s_journal_uuid,
    467 			   sizeof(jsuper.s_uuid))) {
    468 			retval = EXT2_ET_LOAD_EXT_JOURNAL;
    469 			brelse(bh);
    470 			goto errout;
    471 		}
    472 
    473 		/* Check the superblock checksum */
    474 		if (ext2fs_has_feature_metadata_csum(&jsuper)) {
    475 			struct struct_ext2_filsys fsx;
    476 			struct ext2_super_block	superx;
    477 			void *p;
    478 
    479 			p = start ? bh->b_data : bh->b_data + SUPERBLOCK_OFFSET;
    480 			memcpy(&fsx, fs, sizeof(fsx));
    481 			memcpy(&superx, fs->super, sizeof(superx));
    482 			fsx.super = &superx;
    483 			ext2fs_set_feature_metadata_csum(fsx.super);
    484 			if (!ext2fs_superblock_csum_verify(&fsx, p)) {
    485 				retval = EXT2_ET_LOAD_EXT_JOURNAL;
    486 				brelse(bh);
    487 				goto errout;
    488 			}
    489 		}
    490 		brelse(bh);
    491 
    492 		maxlen = ext2fs_blocks_count(&jsuper);
    493 		journal->j_maxlen = (maxlen < 1ULL << 32) ? maxlen :
    494 				    (1ULL << 32) - 1;
    495 		start++;
    496 	}
    497 
    498 	bh = getblk(dev_journal, start, journal->j_blocksize);
    499 	if (!bh) {
    500 		retval = EXT2_ET_NO_MEMORY;
    501 		goto errout;
    502 	}
    503 
    504 	journal->j_sb_buffer = bh;
    505 	journal->j_superblock = (journal_superblock_t *)bh->b_data;
    506 
    507 #ifdef USE_INODE_IO
    508 	if (j_inode)
    509 		ext2fs_free_mem(&j_inode);
    510 #endif
    511 
    512 	*ret_journal = journal;
    513 	return 0;
    514 
    515 errout:
    516 	if (dev_fs)
    517 		ext2fs_free_mem(&dev_fs);
    518 	if (j_inode)
    519 		ext2fs_free_mem(&j_inode);
    520 	if (journal)
    521 		ext2fs_free_mem(&journal);
    522 	return retval;
    523 }
    524 
    525 static errcode_t ext2fs_journal_fix_bad_inode(ext2_filsys fs)
    526 {
    527 	struct ext2_super_block *sb = fs->super;
    528 	int recover = ext2fs_has_feature_journal_needs_recovery(fs->super);
    529 	int has_journal = ext2fs_has_feature_journal(fs->super);
    530 
    531 	if (has_journal || sb->s_journal_inum) {
    532 		/* The journal inode is bogus, remove and force full fsck */
    533 		return EXT2_ET_BAD_INODE_NUM;
    534 	} else if (recover) {
    535 		return EXT2_ET_UNSUPP_FEATURE;
    536 	}
    537 	return 0;
    538 }
    539 
    540 #define V1_SB_SIZE	0x0024
    541 static void clear_v2_journal_fields(journal_t *journal)
    542 {
    543 	ext2_filsys fs = journal->j_dev->k_fs;
    544 
    545 	memset(((char *) journal->j_superblock) + V1_SB_SIZE, 0,
    546 	       fs->blocksize-V1_SB_SIZE);
    547 	mark_buffer_dirty(journal->j_sb_buffer);
    548 }
    549 
    550 
    551 static errcode_t ext2fs_journal_load(journal_t *journal)
    552 {
    553 	ext2_filsys fs = journal->j_dev->k_fs;
    554 	journal_superblock_t *jsb;
    555 	struct buffer_head *jbh = journal->j_sb_buffer;
    556 
    557 	ll_rw_block(READ, 1, &jbh);
    558 	if (jbh->b_err)
    559 		return jbh->b_err;
    560 
    561 	jsb = journal->j_superblock;
    562 	/* If we don't even have JFS_MAGIC, we probably have a wrong inode */
    563 	if (jsb->s_header.h_magic != htonl(JFS_MAGIC_NUMBER))
    564 		return ext2fs_journal_fix_bad_inode(fs);
    565 
    566 	switch (ntohl(jsb->s_header.h_blocktype)) {
    567 	case JFS_SUPERBLOCK_V1:
    568 		journal->j_format_version = 1;
    569 		if (jsb->s_feature_compat ||
    570 		    jsb->s_feature_incompat ||
    571 		    jsb->s_feature_ro_compat ||
    572 		    jsb->s_nr_users)
    573 			clear_v2_journal_fields(journal);
    574 		break;
    575 
    576 	case JFS_SUPERBLOCK_V2:
    577 		journal->j_format_version = 2;
    578 		if (ntohl(jsb->s_nr_users) > 1 &&
    579 		    uuid_is_null(fs->super->s_journal_uuid))
    580 			clear_v2_journal_fields(journal);
    581 		if (ntohl(jsb->s_nr_users) > 1)
    582 			return EXT2_ET_JOURNAL_UNSUPP_VERSION;
    583 		break;
    584 
    585 	/*
    586 	 * These should never appear in a journal super block, so if
    587 	 * they do, the journal is badly corrupted.
    588 	 */
    589 	case JFS_DESCRIPTOR_BLOCK:
    590 	case JFS_COMMIT_BLOCK:
    591 	case JFS_REVOKE_BLOCK:
    592 		return EXT2_ET_CORRUPT_JOURNAL_SB;
    593 
    594 	/* If we don't understand the superblock major type, but there
    595 	 * is a magic number, then it is likely to be a new format we
    596 	 * just don't understand, so leave it alone. */
    597 	default:
    598 		return EXT2_ET_JOURNAL_UNSUPP_VERSION;
    599 	}
    600 
    601 	if (JFS_HAS_INCOMPAT_FEATURE(journal, ~JFS_KNOWN_INCOMPAT_FEATURES))
    602 		return EXT2_ET_UNSUPP_FEATURE;
    603 
    604 	if (JFS_HAS_RO_COMPAT_FEATURE(journal, ~JFS_KNOWN_ROCOMPAT_FEATURES))
    605 		return EXT2_ET_RO_UNSUPP_FEATURE;
    606 
    607 	/* Checksum v1-3 are mutually exclusive features. */
    608 	if (jfs_has_feature_csum2(journal) && jfs_has_feature_csum3(journal))
    609 		return EXT2_ET_CORRUPT_JOURNAL_SB;
    610 
    611 	if (journal_has_csum_v2or3(journal) &&
    612 	    jfs_has_feature_checksum(journal))
    613 		return EXT2_ET_CORRUPT_JOURNAL_SB;
    614 
    615 	if (!ext2fs_journal_verify_csum_type(journal, jsb) ||
    616 	    !ext2fs_journal_sb_csum_verify(journal, jsb))
    617 		return EXT2_ET_CORRUPT_JOURNAL_SB;
    618 
    619 	if (journal_has_csum_v2or3(journal))
    620 		journal->j_csum_seed = jbd2_chksum(journal, ~0, jsb->s_uuid,
    621 						   sizeof(jsb->s_uuid));
    622 
    623 	/* We have now checked whether we know enough about the journal
    624 	 * format to be able to proceed safely, so any other checks that
    625 	 * fail we should attempt to recover from. */
    626 	if (jsb->s_blocksize != htonl(journal->j_blocksize))
    627 		return EXT2_ET_CORRUPT_JOURNAL_SB;
    628 
    629 	if (ntohl(jsb->s_maxlen) < journal->j_maxlen)
    630 		journal->j_maxlen = ntohl(jsb->s_maxlen);
    631 	else if (ntohl(jsb->s_maxlen) > journal->j_maxlen)
    632 		return EXT2_ET_CORRUPT_JOURNAL_SB;
    633 
    634 	journal->j_tail_sequence = ntohl(jsb->s_sequence);
    635 	journal->j_transaction_sequence = journal->j_tail_sequence;
    636 	journal->j_tail = ntohl(jsb->s_start);
    637 	journal->j_first = ntohl(jsb->s_first);
    638 	journal->j_last = ntohl(jsb->s_maxlen);
    639 
    640 	return 0;
    641 }
    642 
    643 static void ext2fs_journal_release(ext2_filsys fs, journal_t *journal,
    644 				   int reset, int drop)
    645 {
    646 	journal_superblock_t *jsb;
    647 
    648 	if (drop)
    649 		mark_buffer_clean(journal->j_sb_buffer);
    650 	else if (fs->flags & EXT2_FLAG_RW) {
    651 		jsb = journal->j_superblock;
    652 		jsb->s_sequence = htonl(journal->j_tail_sequence);
    653 		if (reset)
    654 			jsb->s_start = 0; /* this marks the journal as empty */
    655 		ext2fs_journal_sb_csum_set(journal, jsb);
    656 		mark_buffer_dirty(journal->j_sb_buffer);
    657 	}
    658 	brelse(journal->j_sb_buffer);
    659 
    660 	if (fs && fs->journal_io) {
    661 		if (fs->io != fs->journal_io)
    662 			io_channel_close(fs->journal_io);
    663 		fs->journal_io = NULL;
    664 		free(fs->journal_name);
    665 		fs->journal_name = NULL;
    666 	}
    667 
    668 #ifndef USE_INODE_IO
    669 	if (journal->j_inode)
    670 		ext2fs_free_mem(&journal->j_inode);
    671 #endif
    672 	if (journal->j_fs_dev)
    673 		ext2fs_free_mem(&journal->j_fs_dev);
    674 	ext2fs_free_mem(&journal);
    675 }
    676 
    677 /*
    678  * This function makes sure that the superblock fields regarding the
    679  * journal are consistent.
    680  */
    681 static errcode_t ext2fs_check_ext3_journal(ext2_filsys fs)
    682 {
    683 	struct ext2_super_block *sb = fs->super;
    684 	journal_t *journal;
    685 	int recover = ext2fs_has_feature_journal_needs_recovery(fs->super);
    686 	errcode_t retval;
    687 
    688 	/* If we don't have any journal features, don't do anything more */
    689 	if (!ext2fs_has_feature_journal(sb) &&
    690 	    !recover && sb->s_journal_inum == 0 && sb->s_journal_dev == 0 &&
    691 	    uuid_is_null(sb->s_journal_uuid))
    692 		return 0;
    693 
    694 	retval = ext2fs_get_journal(fs, &journal);
    695 	if (retval)
    696 		return retval;
    697 
    698 	retval = ext2fs_journal_load(journal);
    699 	if (retval)
    700 		goto err;
    701 
    702 	/*
    703 	 * We want to make the flags consistent here.  We will not leave with
    704 	 * needs_recovery set but has_journal clear.  We can't get in a loop
    705 	 * with -y, -n, or -p, only if a user isn't making up their mind.
    706 	 */
    707 	if (!ext2fs_has_feature_journal(sb)) {
    708 		retval = EXT2_ET_JOURNAL_FLAGS_WRONG;
    709 		goto err;
    710 	}
    711 
    712 	if (ext2fs_has_feature_journal(sb) &&
    713 	    !ext2fs_has_feature_journal_needs_recovery(sb) &&
    714 	    journal->j_superblock->s_start != 0) {
    715 		retval = EXT2_ET_JOURNAL_FLAGS_WRONG;
    716 		goto err;
    717 	}
    718 
    719 	/*
    720 	 * If we don't need to do replay the journal, check to see if
    721 	 * the journal's errno is set; if so, we need to mark the file
    722 	 * system as being corrupt and clear the journal's s_errno.
    723 	 */
    724 	if (!ext2fs_has_feature_journal_needs_recovery(sb) &&
    725 	    journal->j_superblock->s_errno) {
    726 		fs->super->s_state |= EXT2_ERROR_FS;
    727 		ext2fs_mark_super_dirty(fs);
    728 		journal->j_superblock->s_errno = 0;
    729 		ext2fs_journal_sb_csum_set(journal, journal->j_superblock);
    730 		mark_buffer_dirty(journal->j_sb_buffer);
    731 	}
    732 
    733 err:
    734 	ext2fs_journal_release(fs, journal, 0, retval ? 1 : 0);
    735 	return retval;
    736 }
    737 
    738 static errcode_t recover_ext3_journal(ext2_filsys fs)
    739 {
    740 	journal_t *journal;
    741 	errcode_t retval;
    742 
    743 	journal_init_revoke_caches();
    744 	retval = ext2fs_get_journal(fs, &journal);
    745 	if (retval)
    746 		return retval;
    747 
    748 	retval = ext2fs_journal_load(journal);
    749 	if (retval)
    750 		goto errout;
    751 
    752 	retval = journal_init_revoke(journal, 1024);
    753 	if (retval)
    754 		goto errout;
    755 
    756 	retval = -journal_recover(journal);
    757 	if (retval)
    758 		goto errout;
    759 
    760 	if (journal->j_failed_commit) {
    761 		journal->j_superblock->s_errno = -EINVAL;
    762 		mark_buffer_dirty(journal->j_sb_buffer);
    763 	}
    764 
    765 errout:
    766 	journal_destroy_revoke(journal);
    767 	journal_destroy_revoke_caches();
    768 	ext2fs_journal_release(fs, journal, 1, 0);
    769 	return retval;
    770 }
    771 
    772 errcode_t ext2fs_run_ext3_journal(ext2_filsys *fsp)
    773 {
    774 	ext2_filsys fs = *fsp;
    775 	io_manager io_ptr = fs->io->manager;
    776 	errcode_t	retval, recover_retval;
    777 	io_stats	stats = 0;
    778 	unsigned long long kbytes_written = 0;
    779 	char *fsname;
    780 	int fsflags;
    781 	int fsblocksize;
    782 
    783 	if (!(fs->flags & EXT2_FLAG_RW))
    784 		return EXT2_ET_FILE_RO;
    785 
    786 	if (fs->flags & EXT2_FLAG_DIRTY)
    787 		ext2fs_flush(fs);	/* Force out any modifications */
    788 
    789 	recover_retval = recover_ext3_journal(fs);
    790 
    791 	/*
    792 	 * Reload the filesystem context to get up-to-date data from disk
    793 	 * because journal recovery will change the filesystem under us.
    794 	 */
    795 	if (fs->super->s_kbytes_written &&
    796 	    fs->io->manager->get_stats)
    797 		fs->io->manager->get_stats(fs->io, &stats);
    798 	if (stats && stats->bytes_written)
    799 		kbytes_written = stats->bytes_written >> 10;
    800 
    801 	ext2fs_mmp_stop(fs);
    802 	fsname = fs->device_name;
    803 	fs->device_name = NULL;
    804 	fsflags = fs->flags;
    805 	fsblocksize = fs->blocksize;
    806 	ext2fs_free(fs);
    807 	*fsp = NULL;
    808 	retval = ext2fs_open(fsname, fsflags, 0, fsblocksize, io_ptr, fsp);
    809 	ext2fs_free_mem(&fsname);
    810 	if (retval)
    811 		return retval;
    812 
    813 	fs = *fsp;
    814 	fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
    815 	fs->super->s_kbytes_written += kbytes_written;
    816 
    817 	/* Set the superblock flags */
    818 	ext2fs_clear_recover(fs, recover_retval != 0);
    819 
    820 	/*
    821 	 * Do one last sanity check, and propagate journal->s_errno to
    822 	 * the EXT2_ERROR_FS flag in the fs superblock if needed.
    823 	 */
    824 	retval = ext2fs_check_ext3_journal(fs);
    825 	return retval ? retval : recover_retval;
    826 }
    827 
    828 errcode_t ext2fs_open_journal(ext2_filsys fs, journal_t **j)
    829 {
    830 	journal_t *journal;
    831 	errcode_t retval;
    832 
    833 	journal_init_revoke_caches();
    834 	retval = ext2fs_get_journal(fs, &journal);
    835 	if (retval)
    836 		return retval;
    837 
    838 	retval = ext2fs_journal_load(journal);
    839 	if (retval)
    840 		goto errout;
    841 
    842 	retval = journal_init_revoke(journal, 1024);
    843 	if (retval)
    844 		goto errout;
    845 
    846 	if (journal->j_failed_commit) {
    847 		journal->j_superblock->s_errno = -EINVAL;
    848 		mark_buffer_dirty(journal->j_sb_buffer);
    849 	}
    850 
    851 	*j = journal;
    852 	return 0;
    853 
    854 errout:
    855 	journal_destroy_revoke(journal);
    856 	journal_destroy_revoke_caches();
    857 	ext2fs_journal_release(fs, journal, 1, 0);
    858 	return retval;
    859 }
    860 
    861 errcode_t ext2fs_close_journal(ext2_filsys fs, journal_t **j)
    862 {
    863 	journal_t *journal = *j;
    864 
    865 	journal_destroy_revoke(journal);
    866 	journal_destroy_revoke_caches();
    867 	ext2fs_journal_release(fs, journal, 0, 0);
    868 	*j = NULL;
    869 
    870 	return 0;
    871 }
    872 
    873 void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
    874 {
    875 	struct commit_header *h;
    876 	__u32 csum;
    877 
    878 	if (!journal_has_csum_v2or3(j))
    879 		return;
    880 
    881 	h = (struct commit_header *)(bh->b_data);
    882 	h->h_chksum_type = 0;
    883 	h->h_chksum_size = 0;
    884 	h->h_chksum[0] = 0;
    885 	csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
    886 	h->h_chksum[0] = ext2fs_cpu_to_be32(csum);
    887 }
    888 
    889 void jbd2_revoke_csum_set(journal_t *j, struct buffer_head *bh)
    890 {
    891 	struct journal_revoke_tail *tail;
    892 	__u32 csum;
    893 
    894 	if (!journal_has_csum_v2or3(j))
    895 		return;
    896 
    897 	tail = (struct journal_revoke_tail *)(bh->b_data + j->j_blocksize -
    898 			sizeof(struct journal_revoke_tail));
    899 	tail->r_checksum = 0;
    900 	csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
    901 	tail->r_checksum = ext2fs_cpu_to_be32(csum);
    902 }
    903 
    904 void jbd2_descr_block_csum_set(journal_t *j, struct buffer_head *bh)
    905 {
    906 	struct journal_block_tail *tail;
    907 	__u32 csum;
    908 
    909 	if (!journal_has_csum_v2or3(j))
    910 		return;
    911 
    912 	tail = (struct journal_block_tail *)(bh->b_data + j->j_blocksize -
    913 			sizeof(struct journal_block_tail));
    914 	tail->t_checksum = 0;
    915 	csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
    916 	tail->t_checksum = ext2fs_cpu_to_be32(csum);
    917 }
    918 
    919 void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
    920 			     struct buffer_head *bh, __u32 sequence)
    921 {
    922 	journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
    923 	__u32 csum32;
    924 	__be32 seq;
    925 
    926 	if (!journal_has_csum_v2or3(j))
    927 		return;
    928 
    929 	seq = ext2fs_cpu_to_be32(sequence);
    930 	csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
    931 	csum32 = jbd2_chksum(j, csum32, bh->b_data, bh->b_size);
    932 
    933 	if (jfs_has_feature_csum3(j))
    934 		tag3->t_checksum = ext2fs_cpu_to_be32(csum32);
    935 	else
    936 		tag->t_checksum = ext2fs_cpu_to_be16(csum32);
    937 }
    938 
    939