e2fsck.c

busybox最新版的源码:学习和应用的好东东,多的不说了,大家看后再说吧

static void e2fsck_clear_recover(e2fsck_t ctx, int error)
{
	ctx->fs->super->s_feature_incompat &= ~EXT3_FEATURE_INCOMPAT_RECOVER;

	/* if we had an error doing journal recovery, we need a full fsck */
	if (error)
		ctx->fs->super->s_state &= ~EXT2_VALID_FS;
	ext2fs_mark_super_dirty(ctx->fs);
}

static errcode_t e2fsck_get_journal(e2fsck_t ctx, journal_t **ret_journal)
{
	struct ext2_super_block *sb = ctx->fs->super;
	struct ext2_super_block jsuper;
	struct problem_context  pctx;
	struct buffer_head      *bh;
	struct inode            *j_inode = NULL;
	struct kdev_s           *dev_fs = NULL, *dev_journal;
	const char              *journal_name = 0;
	journal_t               *journal = NULL;
	errcode_t               retval = 0;
	io_manager              io_ptr = 0;
	unsigned long           start = 0;
	blk_t                   blk;
	int                     ext_journal = 0;
	int                     tried_backup_jnl = 0;
	int                     i;

	clear_problem_context(&pctx);

	journal = e2fsck_allocate_memory(ctx, sizeof(journal_t), "journal");
	if (!journal) {
		return EXT2_ET_NO_MEMORY;
	}

	dev_fs = e2fsck_allocate_memory(ctx, 2*sizeof(struct kdev_s), "kdev");
	if (!dev_fs) {
		retval = EXT2_ET_NO_MEMORY;
		goto errout;
	}
	dev_journal = dev_fs+1;

	dev_fs->k_ctx = dev_journal->k_ctx = ctx;
	dev_fs->k_dev = K_DEV_FS;
	dev_journal->k_dev = K_DEV_JOURNAL;

	journal->j_dev = dev_journal;
	journal->j_fs_dev = dev_fs;
	journal->j_inode = NULL;
	journal->j_blocksize = ctx->fs->blocksize;

	if (uuid_is_null(sb->s_journal_uuid)) {
		if (!sb->s_journal_inum)
			return EXT2_ET_BAD_INODE_NUM;
		j_inode = e2fsck_allocate_memory(ctx, sizeof(*j_inode),
						 "journal inode");
		if (!j_inode) {
			retval = EXT2_ET_NO_MEMORY;
			goto errout;
		}

		j_inode->i_ctx = ctx;
		j_inode->i_ino = sb->s_journal_inum;

		if ((retval = ext2fs_read_inode(ctx->fs,
						sb->s_journal_inum,
						&j_inode->i_ext2))) {
		try_backup_journal:
			if (sb->s_jnl_backup_type != EXT3_JNL_BACKUP_BLOCKS ||
			    tried_backup_jnl)
				goto errout;
			memset(&j_inode->i_ext2, 0, sizeof(struct ext2_inode));
			memcpy(&j_inode->i_ext2.i_block[0], sb->s_jnl_blocks,
			       EXT2_N_BLOCKS*4);
			j_inode->i_ext2.i_size = sb->s_jnl_blocks[16];
			j_inode->i_ext2.i_links_count = 1;
			j_inode->i_ext2.i_mode = LINUX_S_IFREG | 0600;
			tried_backup_jnl++;
		}
		if (!j_inode->i_ext2.i_links_count ||
		    !LINUX_S_ISREG(j_inode->i_ext2.i_mode)) {
			retval = EXT2_ET_NO_JOURNAL;
			goto try_backup_journal;
		}
		if (j_inode->i_ext2.i_size / journal->j_blocksize <
		    JFS_MIN_JOURNAL_BLOCKS) {
			retval = EXT2_ET_JOURNAL_TOO_SMALL;
			goto try_backup_journal;
		}
		for (i=0; i < EXT2_N_BLOCKS; i++) {
			blk = j_inode->i_ext2.i_block[i];
			if (!blk) {
				if (i < EXT2_NDIR_BLOCKS) {
					retval = EXT2_ET_JOURNAL_TOO_SMALL;
					goto try_backup_journal;
				}
				continue;
			}
			if (blk < sb->s_first_data_block ||
			    blk >= sb->s_blocks_count) {
				retval = EXT2_ET_BAD_BLOCK_NUM;
				goto try_backup_journal;
			}
		}
		journal->j_maxlen = j_inode->i_ext2.i_size / journal->j_blocksize;

#ifdef USE_INODE_IO
		retval = ext2fs_inode_io_intern2(ctx->fs, sb->s_journal_inum,
						 &j_inode->i_ext2,
						 &journal_name);
		if (retval)
			goto errout;

		io_ptr = inode_io_manager;
#else
		journal->j_inode = j_inode;
		ctx->journal_io = ctx->fs->io;
		if ((retval = journal_bmap(journal, 0, &start)) != 0)
			goto errout;
#endif
	} else {
		ext_journal = 1;
		if (!ctx->journal_name) {
			char uuid[37];

			uuid_unparse(sb->s_journal_uuid, uuid);
			ctx->journal_name = blkid_get_devname(ctx->blkid,
							      "UUID", uuid);
			if (!ctx->journal_name)
				ctx->journal_name = blkid_devno_to_devname(sb->s_journal_dev);
		}
		journal_name = ctx->journal_name;

		if (!journal_name) {
			fix_problem(ctx, PR_0_CANT_FIND_JOURNAL, &pctx);
			return EXT2_ET_LOAD_EXT_JOURNAL;
		}

		io_ptr = unix_io_manager;
	}

#ifndef USE_INODE_IO
	if (ext_journal)
#endif
		retval = io_ptr->open(journal_name, IO_FLAG_RW,
				      &ctx->journal_io);
	if (retval)
		goto errout;

	io_channel_set_blksize(ctx->journal_io, ctx->fs->blocksize);

	if (ext_journal) {
		if (ctx->fs->blocksize == 1024)
			start = 1;
		bh = getblk(dev_journal, start, ctx->fs->blocksize);
		if (!bh) {
			retval = EXT2_ET_NO_MEMORY;
			goto errout;
		}
		ll_rw_block(READ, 1, &bh);
		if ((retval = bh->b_err) != 0)
			goto errout;
		memcpy(&jsuper, start ? bh->b_data :  bh->b_data + 1024,
		       sizeof(jsuper));
		brelse(bh);
#if BB_BIG_ENDIAN
		if (jsuper.s_magic == ext2fs_swab16(EXT2_SUPER_MAGIC))
			ext2fs_swap_super(&jsuper);
#endif
		if (jsuper.s_magic != EXT2_SUPER_MAGIC ||
		    !(jsuper.s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
			fix_problem(ctx, PR_0_EXT_JOURNAL_BAD_SUPER, &pctx);
			retval = EXT2_ET_LOAD_EXT_JOURNAL;
			goto errout;
		}
		/* Make sure the journal UUID is correct */
		if (memcmp(jsuper.s_uuid, ctx->fs->super->s_journal_uuid,
			   sizeof(jsuper.s_uuid))) {
			fix_problem(ctx, PR_0_JOURNAL_BAD_UUID, &pctx);
			retval = EXT2_ET_LOAD_EXT_JOURNAL;
			goto errout;
		}

		journal->j_maxlen = jsuper.s_blocks_count;
		start++;
	}

	if (!(bh = getblk(dev_journal, start, journal->j_blocksize))) {
		retval = EXT2_ET_NO_MEMORY;
		goto errout;
	}

	journal->j_sb_buffer = bh;
	journal->j_superblock = (journal_superblock_t *)bh->b_data;

#ifdef USE_INODE_IO
	ext2fs_free_mem(&j_inode);
#endif

	*ret_journal = journal;
	return 0;

errout:
	ext2fs_free_mem(&dev_fs);
	ext2fs_free_mem(&j_inode);
	ext2fs_free_mem(&journal);
	return retval;

}

static errcode_t e2fsck_journal_fix_bad_inode(e2fsck_t ctx,
					      struct problem_context *pctx)
{
	struct ext2_super_block *sb = ctx->fs->super;
	int recover = ctx->fs->super->s_feature_incompat &
		EXT3_FEATURE_INCOMPAT_RECOVER;
	int has_journal = ctx->fs->super->s_feature_compat &
		EXT3_FEATURE_COMPAT_HAS_JOURNAL;

	if (has_journal || sb->s_journal_inum) {
		/* The journal inode is bogus, remove and force full fsck */
		pctx->ino = sb->s_journal_inum;
		if (fix_problem(ctx, PR_0_JOURNAL_BAD_INODE, pctx)) {
			if (has_journal && sb->s_journal_inum)
				printf("*** ext3 journal has been deleted - "
				       "filesystem is now ext2 only ***\n\n");
			sb->s_feature_compat &= ~EXT3_FEATURE_COMPAT_HAS_JOURNAL;
			sb->s_journal_inum = 0;
			ctx->flags |= E2F_FLAG_JOURNAL_INODE; /* FIXME: todo */
			e2fsck_clear_recover(ctx, 1);
			return 0;
		}
		return EXT2_ET_BAD_INODE_NUM;
	} else if (recover) {
		if (fix_problem(ctx, PR_0_JOURNAL_RECOVER_SET, pctx)) {
			e2fsck_clear_recover(ctx, 1);
			return 0;
		}
		return EXT2_ET_UNSUPP_FEATURE;
	}
	return 0;
}

#define V1_SB_SIZE      0x0024
static void clear_v2_journal_fields(journal_t *journal)
{
	e2fsck_t ctx = journal->j_dev->k_ctx;
	struct problem_context pctx;

	clear_problem_context(&pctx);

	if (!fix_problem(ctx, PR_0_CLEAR_V2_JOURNAL, &pctx))
		return;

	memset(((char *) journal->j_superblock) + V1_SB_SIZE, 0,
	       ctx->fs->blocksize-V1_SB_SIZE);
	mark_buffer_dirty(journal->j_sb_buffer);
}


static errcode_t e2fsck_journal_load(journal_t *journal)
{
	e2fsck_t ctx = journal->j_dev->k_ctx;
	journal_superblock_t *jsb;
	struct buffer_head *jbh = journal->j_sb_buffer;
	struct problem_context pctx;

	clear_problem_context(&pctx);

	ll_rw_block(READ, 1, &jbh);
	if (jbh->b_err) {
		bb_error_msg(_("reading journal superblock"));
		return jbh->b_err;
	}

	jsb = journal->j_superblock;
	/* If we don't even have JFS_MAGIC, we probably have a wrong inode */
	if (jsb->s_header.h_magic != htonl(JFS_MAGIC_NUMBER))
		return e2fsck_journal_fix_bad_inode(ctx, &pctx);

	switch (ntohl(jsb->s_header.h_blocktype)) {
	case JFS_SUPERBLOCK_V1:
		journal->j_format_version = 1;
		if (jsb->s_feature_compat ||
		    jsb->s_feature_incompat ||
		    jsb->s_feature_ro_compat ||
		    jsb->s_nr_users)
			clear_v2_journal_fields(journal);
		break;

	case JFS_SUPERBLOCK_V2:
		journal->j_format_version = 2;
		if (ntohl(jsb->s_nr_users) > 1 &&
		    uuid_is_null(ctx->fs->super->s_journal_uuid))
			clear_v2_journal_fields(journal);
		if (ntohl(jsb->s_nr_users) > 1) {
			fix_problem(ctx, PR_0_JOURNAL_UNSUPP_MULTIFS, &pctx);
			return EXT2_ET_JOURNAL_UNSUPP_VERSION;
		}
		break;

	/*
	 * These should never appear in a journal super block, so if
	 * they do, the journal is badly corrupted.
	 */
	case JFS_DESCRIPTOR_BLOCK:
	case JFS_COMMIT_BLOCK:
	case JFS_REVOKE_BLOCK:
		return EXT2_ET_CORRUPT_SUPERBLOCK;

	/* If we don't understand the superblock major type, but there
	 * is a magic number, then it is likely to be a new format we
	 * just don't understand, so leave it alone. */
	default:
		return EXT2_ET_JOURNAL_UNSUPP_VERSION;
	}

	if (JFS_HAS_INCOMPAT_FEATURE(journal, ~JFS_KNOWN_INCOMPAT_FEATURES))
		return EXT2_ET_UNSUPP_FEATURE;

	if (JFS_HAS_RO_COMPAT_FEATURE(journal, ~JFS_KNOWN_ROCOMPAT_FEATURES))
		return EXT2_ET_RO_UNSUPP_FEATURE;

	/* We have now checked whether we know enough about the journal
	 * format to be able to proceed safely, so any other checks that
	 * fail we should attempt to recover from. */
	if (jsb->s_blocksize != htonl(journal->j_blocksize)) {
		bb_error_msg(_("%s: no valid journal superblock found"),
			ctx->device_name);
		return EXT2_ET_CORRUPT_SUPERBLOCK;
	}

	if (ntohl(jsb->s_maxlen) < journal->j_maxlen)
		journal->j_maxlen = ntohl(jsb->s_maxlen);
	else if (ntohl(jsb->s_maxlen) > journal->j_maxlen) {
		bb_error_msg(_("%s: journal too short"),
			ctx->device_name);
		return EXT2_ET_CORRUPT_SUPERBLOCK;
	}

	journal->j_tail_sequence = ntohl(jsb->s_sequence);
	journal->j_transaction_sequence = journal->j_tail_sequence;
	journal->j_tail = ntohl(jsb->s_start);
	journal->j_first = ntohl(jsb->s_first);
	journal->j_last = ntohl(jsb->s_maxlen);

	return 0;
}

static void e2fsck_journal_reset_super(e2fsck_t ctx, journal_superblock_t *jsb,
				       journal_t *journal)
{
	char *p;
	union {
		uuid_t uuid;
		__u32 val[4];
	} u;
	__u32 new_seq = 0;
	int i;

	/* Leave a valid existing V1 superblock signature alone.
	 * Anything unrecognisable we overwrite with a new V2
	 * signature. */

	if (jsb->s_header.h_magic != htonl(JFS_MAGIC_NUMBER) ||
	    jsb->s_header.h_blocktype != htonl(JFS_SUPERBLOCK_V1)) {
		jsb->s_header.h_magic = htonl(JFS_MAGIC_NUMBER);
		jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V2);
	}

	/* Zero out everything else beyond the superblock header */

	p = ((char *) jsb) + sizeof(journal_header_t);
	memset (p, 0, ctx->fs->blocksize-sizeof(journal_header_t));

	jsb->s_blocksize = htonl(ctx->fs->blocksize);
	jsb->s_maxlen = htonl(journal->j_maxlen);
	jsb->s_first = htonl(1);

	/* Initialize the journal sequence number so that there is "no"
	 * chance we will find old "valid" transactions in the journal.
	 * This avoids the need to zero the whole journal (slow to do,
	 * and risky when we are just recovering the filesystem).
	 */
	uuid_generate(u.uuid);
	for (i = 0; i < 4; i ++)
		new_seq ^= u.val[i];
	jsb->s_sequence = htonl(new_seq);

	mark_buffer_dirty(journal->j_sb_buffer);
	ll_rw_block(WRITE, 1, &journal->j_sb_buffer);
}

static errcode_t e2fsck_journal_fix_corrupt_super(e2fsck_t ctx,
						  journal_t *journal,
						  struct problem_context *pctx)
{
	struct ext2_super_block *sb = ctx->fs->super;
	int recover = ctx->fs->super->s_feature_incompat &
		EXT3_FEATURE_INCOMPAT_RECOVER;

	if (sb->s_feature_compat & EXT3_FEATURE_COMPAT_HAS_JOURNAL) {
		if (fix_problem(ctx, PR_0_JOURNAL_BAD_SUPER, pctx)) {
			e2fsck_journal_reset_super(ctx, journal->j_superblock,
						   journal);
			journal->j_transaction_sequence = 1;
			e2fsck_clear_recover(ctx, recover);
			return 0;
		}
		return EXT2_ET_CORRUPT_SUPERBLOCK;
	} else if (e2fsck_journal_fix_bad_inode(ctx, pctx))
		return EXT2_ET_CORRUPT_SUPERBLOCK;

	return 0;
}

static void e2fsck_journal_release(e2fsck_t ctx, journal_t *journal,
				   int reset, int drop)
{
	journal_superblock_t *jsb;

	if (drop)
		mark_buffer_clean(journal->j_sb_buffer);
	else if (!(ctx->options & E2F_OPT_READONLY)) {
		jsb = journal->j_superblock;
		jsb->s_sequence = htonl(journal->j_transaction_sequence);
		if (reset)
			jsb->s_start = 0; /* this marks the journal as empty */
		mark_buffer_dirty(journal->j_sb_buffer);
	}
	brelse(journal->j_sb_buffer);

	if (ctx->journal_io) {
		if (ctx->fs && ctx->fs->io != ctx->journal_io)
			io_channel_close(ctx->journal_io);
		ctx->journal_io = 0;
	}

#ifndef USE_INODE_IO
	ext2fs_free_mem(&journal->j_inode);
#endif
	ext2fs_free_mem(&journal->j_fs_dev);
	ext2fs_free_mem(&journal);
}

/*
 * This function makes sure that the superblock fields regarding the
 * journal are consistent.
 */
static int e2fsck_check_ext3_journal(e2fsck_t ctx)
{
	struct ext2_super_block *sb = ctx->fs->super;
	journal_t *journal;
	int recover = ctx->fs->super->s_feature_incompat &
		EXT3_FEATURE_INCOMPAT_RECOVER;
	struct problem_context pctx;
	problem_t problem;
	int reset = 0, force_fsck = 0;
	int retval;

	/* If we don't have any journal features, don't do anything more */
	if (!(sb->s_feature_compat & EXT3_FEATURE_COMPAT_HAS_JOURNAL) &&
	    !recover && sb->s_journal_inum == 0 && sb->s_journal_dev == 0 &&
	    uuid_is_null(sb->s_journal_uuid))
		return 0;

	clear_problem_context(&pctx);
	pctx.num = sb->s_journal_inum;

	retval = e2fsck_get_journal(ctx, &journal);
	if (retval) {
		if ((retval == EXT2_ET_BAD_INODE_NUM) ||
		    (retval == EXT2_ET_BAD_BLOCK_NUM) ||
		    (retval == EXT2_ET_JOURNAL_TOO_SMALL) ||
		    (retval == EXT2_ET_NO_JOURNAL))
			return e2fsck_journal_fix_bad_inode(ctx, &pctx);
		return retval;
	}

	retval = e2fsck_journal_load(journal);
	if (retval) {
		if ((retval == EXT2_ET_CORRUPT_SUPERBLOCK) ||
		    ((retval == EXT2_ET_UNSUPP_FEATURE) &&
		    (!fix_problem(ctx, PR_0_JOURNAL_UNSUPP_INCOMPAT,
				  &pctx))) ||
		    ((retval == EXT2_ET_RO_UNSUPP_FEATURE) &&
		    (!fix_problem(ctx, PR_0_JOURNAL_UNSUPP_ROCOMPAT,
				  &pctx))) ||
		    ((retval == EXT2_ET_JOURNAL_UNSUPP_VERSION) &&
		    (!fix_problem(ctx, PR_0_JOURNAL_UNSUPP_VERSION, &pctx))))
			retval = e2fsck_journal_fix_corrupt_super(ctx, journal,
								  &pctx);
		e2fsck_journal_release(ctx, journal, 0, 1);
		return retval;
	}

	/*
	 * We want to make the flags consistent here.  We will not leave with
	 * needs_recovery set but has_journal clear.  We can't get in a loop
	 * with -y, -n, or -p, only if a user isn't making up their mind.
	 */
no_has_journal:
	if (!(sb->s_feature_compat & EXT3_FEATURE_COMPAT_HAS_JOURNAL)) {
		recover = sb->s_feature_incompat & EXT3_FEATURE_INCOMPAT_RECOVER;
		pctx.str = "inode";
		if (fix_problem(ctx, PR_0_JOURNAL_HAS_JOURNAL, &pctx)) {
			if (recover &&
			    !fix_problem(ctx, PR_0_JOURNAL_RECOVER_SET, &pctx))
				goto no_has_journal;