Пример #1
0
/* Allocate the cache buffers */
static errcode_t alloc_cache(io_channel channel,
			     struct unix_private_data *data)
{
	errcode_t		retval;
	struct unix_cache	*cache;
	int			i;

	data->access_time = 0;
	for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
		cache->block = 0;
		cache->access_time = 0;
		cache->dirty = 0;
		cache->in_use = 0;
		if (cache->buf)
			ext2fs_free_mem(&cache->buf);
		retval = io_channel_alloc_buf(channel, 0, &cache->buf);
		if (retval)
			return retval;
	}
	if (channel->align) {
		if (data->bounce)
			ext2fs_free_mem(&data->bounce);
		retval = io_channel_alloc_buf(channel, 0, &data->bounce);
	}
	return retval;
}
Пример #2
0
static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block)
{
	dgrp_t 		i;
	unsigned int	j;
	int		block_nbytes, inode_nbytes;
	unsigned int	nbits;
	errcode_t	retval;
	char		*block_buf = NULL, *inode_buf = NULL;
	int		csum_flag = 0;
	blk64_t		blk;
	blk64_t		blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
	ext2_ino_t	ino_itr = 1;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (!(fs->flags & EXT2_FLAG_RW))
		return EXT2_ET_RO_FILSYS;

	if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
				       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
		csum_flag = 1;

	inode_nbytes = block_nbytes = 0;
	if (do_block) {
		block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
		retval = io_channel_alloc_buf(fs->io, 0, &block_buf);
		if (retval)
			goto errout;
		memset(block_buf, 0xff, fs->blocksize);
	}
	if (do_inode) {
		inode_nbytes = (size_t)
			((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
		retval = io_channel_alloc_buf(fs->io, 0, &inode_buf);
		if (retval)
			goto errout;
		memset(inode_buf, 0xff, fs->blocksize);
	}

	for (i = 0; i < fs->group_desc_count; i++) {
		if (!do_block)
			goto skip_block_bitmap;

		if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT)
		    )
			goto skip_this_block_bitmap;

		retval = ext2fs_get_block_bitmap_range2(fs->block_map,
				blk_itr, block_nbytes << 3, block_buf);
		if (retval)
			goto errout;

		if (i == fs->group_desc_count - 1) {
			/* Force bitmap padding for the last group */
			nbits = EXT2FS_NUM_B2C(fs,
				((ext2fs_blocks_count(fs->super)
				  - (__u64) fs->super->s_first_data_block)
				 % (__u64) EXT2_BLOCKS_PER_GROUP(fs->super)));
			if (nbits)
				for (j = nbits; j < fs->blocksize * 8; j++)
					ext2fs_set_bit(j, block_buf);
		}
		blk = ext2fs_block_bitmap_loc(fs, i);
		if (blk) {
			retval = io_channel_write_blk64(fs->io, blk, 1,
							block_buf);
			if (retval) {
				retval = EXT2_ET_BLOCK_BITMAP_WRITE;
				goto errout;
			}
		}
	skip_this_block_bitmap:
		blk_itr += block_nbytes << 3;
	skip_block_bitmap:

		if (!do_inode)
			continue;

		if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT)
		    )
			goto skip_this_inode_bitmap;

		retval = ext2fs_get_inode_bitmap_range2(fs->inode_map,
				ino_itr, inode_nbytes << 3, inode_buf);
		if (retval)
			goto errout;

		blk = ext2fs_inode_bitmap_loc(fs, i);
		if (blk) {
			retval = io_channel_write_blk64(fs->io, blk, 1,
						      inode_buf);
			if (retval) {
				retval = EXT2_ET_INODE_BITMAP_WRITE;
				goto errout;
			}
		}
	skip_this_inode_bitmap:
		ino_itr += inode_nbytes << 3;

	}
	if (do_block) {
		fs->flags &= ~EXT2_FLAG_BB_DIRTY;
		ext2fs_free_mem(&block_buf);
	}
	if (do_inode) {
		fs->flags &= ~EXT2_FLAG_IB_DIRTY;
		ext2fs_free_mem(&inode_buf);
	}
	return 0;
errout:
	if (inode_buf)
		ext2fs_free_mem(&inode_buf);
	if (block_buf)
		ext2fs_free_mem(&block_buf);
	return retval;
}
Пример #3
0
static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
{
	dgrp_t i;
	char *block_bitmap = 0, *inode_bitmap = 0;
	char *buf;
	errcode_t retval;
	int block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
	int inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8;
	int csum_flag = 0;
	unsigned int	cnt;
	blk64_t	blk;
	blk64_t	blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
	blk64_t   blk_cnt;
	ext2_ino_t ino_itr = 1;
	ext2_ino_t ino_cnt;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if ((block_nbytes > fs->blocksize) || (inode_nbytes > fs->blocksize))
		return EXT2_ET_CORRUPT_SUPERBLOCK;

	fs->write_bitmaps = ext2fs_write_bitmaps;

	if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
				       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
		csum_flag = 1;

	retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
	if (retval)
		return retval;
	if (do_block) {
		if (fs->block_map)
			ext2fs_free_block_bitmap(fs->block_map);
		strcpy(buf, "block bitmap for ");
		strcat(buf, fs->device_name);
		retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
		if (retval)
			goto cleanup;
		retval = io_channel_alloc_buf(fs->io, 0, &block_bitmap);
		if (retval)
			goto cleanup;
	} else
		block_nbytes = 0;
	if (do_inode) {
		if (fs->inode_map)
			ext2fs_free_inode_bitmap(fs->inode_map);
		strcpy(buf, "inode bitmap for ");
		strcat(buf, fs->device_name);
		retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
		if (retval)
			goto cleanup;
		retval = io_channel_alloc_buf(fs->io, 0, &inode_bitmap);
		if (retval)
			goto cleanup;
	} else
		inode_nbytes = 0;
	ext2fs_free_mem(&buf);

	if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
		blk = (fs->image_header->offset_inodemap / fs->blocksize);
		ino_cnt = fs->super->s_inodes_count;
		while (inode_nbytes > 0) {
			retval = io_channel_read_blk64(fs->image_io, blk++,
						     1, inode_bitmap);
			if (retval)
				goto cleanup;
			cnt = fs->blocksize << 3;
			if (cnt > ino_cnt)
				cnt = ino_cnt;
			retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
					       ino_itr, cnt, inode_bitmap);
			if (retval)
				goto cleanup;
			ino_itr += fs->blocksize << 3;
			ino_cnt -= fs->blocksize << 3;
			inode_nbytes -= fs->blocksize;
		}
		blk = (fs->image_header->offset_blockmap /
		       fs->blocksize);
		blk_cnt = (blk64_t)EXT2_CLUSTERS_PER_GROUP(fs->super) *
			fs->group_desc_count;
		while (block_nbytes > 0) {
			retval = io_channel_read_blk64(fs->image_io, blk++,
						     1, block_bitmap);
			if (retval)
				goto cleanup;
			cnt = fs->blocksize << 3;
			if (cnt > blk_cnt)
				cnt = blk_cnt;
			retval = ext2fs_set_block_bitmap_range2(fs->block_map,
				       blk_itr, cnt, block_bitmap);
			if (retval)
				goto cleanup;
			blk_itr += fs->blocksize << 3;
			blk_cnt -= fs->blocksize << 3;
			block_nbytes -= fs->blocksize;
		}
		goto success_cleanup;
	}

	for (i = 0; i < fs->group_desc_count; i++) {
		if (block_bitmap) {
			blk = ext2fs_block_bitmap_loc(fs, i);
			if (csum_flag &&
			    ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT) &&
			    ext2fs_group_desc_csum_verify(fs, i))
				blk = 0;
			if (blk) {
				retval = io_channel_read_blk64(fs->io, blk,
							       1, block_bitmap);
				if (retval) {
					retval = EXT2_ET_BLOCK_BITMAP_READ;
					goto cleanup;
				}
			} else
				memset(block_bitmap, 0, block_nbytes);
			cnt = block_nbytes << 3;
			retval = ext2fs_set_block_bitmap_range2(fs->block_map,
					       blk_itr, cnt, block_bitmap);
			if (retval)
				goto cleanup;
			blk_itr += block_nbytes << 3;
		}
		if (inode_bitmap) {
			blk = ext2fs_inode_bitmap_loc(fs, i);
			if (csum_flag &&
			    ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT) &&
			    ext2fs_group_desc_csum_verify(fs, i))
				blk = 0;
			if (blk) {
				retval = io_channel_read_blk64(fs->io, blk,
							       1, inode_bitmap);
				if (retval) {
					retval = EXT2_ET_INODE_BITMAP_READ;
					goto cleanup;
				}
			} else
				memset(inode_bitmap, 0, inode_nbytes);
			cnt = inode_nbytes << 3;
			retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
					       ino_itr, cnt, inode_bitmap);
			if (retval)
				goto cleanup;
			ino_itr += inode_nbytes << 3;
		}
	}
success_cleanup:
	if (inode_bitmap)
		ext2fs_free_mem(&inode_bitmap);
	if (block_bitmap)
		ext2fs_free_mem(&block_bitmap);
	return 0;

cleanup:
	if (do_block) {
		ext2fs_free_mem(&fs->block_map);
		fs->block_map = 0;
	}
	if (do_inode) {
		ext2fs_free_mem(&fs->inode_map);
		fs->inode_map = 0;
	}
	if (inode_bitmap)
		ext2fs_free_mem(&inode_bitmap);
	if (block_bitmap)
		ext2fs_free_mem(&block_bitmap);
	if (buf)
		ext2fs_free_mem(&buf);
	return retval;
}
Пример #4
0
errcode_t ext2fs_open_inode_scan(ext2_filsys fs, int buffer_blocks,
				 ext2_inode_scan *ret_scan)
{
	ext2_inode_scan	scan;
	errcode_t	retval;
	errcode_t (*save_get_blocks)(ext2_filsys f, ext2_ino_t ino, blk_t *blocks);

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	/*
	 * If fs->badblocks isn't set, then set it --- since the inode
	 * scanning functions require it.
	 */
	if (fs->badblocks == 0) {
		/*
		 * Temporarly save fs->get_blocks and set it to zero,
		 * for compatibility with old e2fsck's.
		 */
		save_get_blocks = fs->get_blocks;
		fs->get_blocks = 0;
		retval = ext2fs_read_bb_inode(fs, &fs->badblocks);
		if (retval && fs->badblocks) {
			ext2fs_badblocks_list_free(fs->badblocks);
			fs->badblocks = 0;
		}
		fs->get_blocks = save_get_blocks;
	}

	retval = ext2fs_get_mem(sizeof(struct ext2_struct_inode_scan), &scan);
	if (retval)
		return retval;
	memset(scan, 0, sizeof(struct ext2_struct_inode_scan));

	scan->magic = EXT2_ET_MAGIC_INODE_SCAN;
	scan->fs = fs;
	scan->inode_size = EXT2_INODE_SIZE(fs->super);
	scan->bytes_left = 0;
	scan->current_group = 0;
	scan->groups_left = fs->group_desc_count - 1;
	scan->inode_buffer_blocks = buffer_blocks ? buffer_blocks :
				    EXT2_INODE_SCAN_DEFAULT_BUFFER_BLOCKS;
	scan->current_block = ext2fs_inode_table_loc(scan->fs,
						     scan->current_group);
	scan->inodes_left = EXT2_INODES_PER_GROUP(scan->fs->super);
	scan->blocks_left = scan->fs->inode_blocks_per_group;
	if (ext2fs_has_group_desc_csum(fs)) {
		__u32 unused = ext2fs_bg_itable_unused(fs, scan->current_group);
		if (scan->inodes_left > unused)
			scan->inodes_left -= unused;
		else
			scan->inodes_left = 0;
		scan->blocks_left =
			(scan->inodes_left +
			 (fs->blocksize / scan->inode_size - 1)) *
			scan->inode_size / fs->blocksize;
	}
	retval = io_channel_alloc_buf(fs->io, scan->inode_buffer_blocks,
				      &scan->inode_buffer);
	scan->done_group = 0;
	scan->done_group_data = 0;
	scan->bad_block_ptr = 0;
	if (retval) {
		ext2fs_free_mem(&scan);
		return retval;
	}
	retval = ext2fs_get_mem(scan->inode_size + scan->inode_buffer_blocks,
				&scan->temp_buffer);
	if (retval) {
		ext2fs_free_mem(&scan->inode_buffer);
		ext2fs_free_mem(&scan);
		return retval;
	}
	memset(SCAN_BLOCK_STATUS(scan), 0, scan->inode_buffer_blocks);
	if (scan->fs->badblocks && scan->fs->badblocks->num)
		scan->scan_flags |= EXT2_SF_CHK_BADBLOCKS;
	if (ext2fs_has_group_desc_csum(fs))
		scan->scan_flags |= EXT2_SF_DO_LAZY;
	*ret_scan = scan;
	return 0;
}
Пример #5
0
/*
 *  Note: if superblock is non-zero, block-size must also be non-zero.
 * 	Superblock and block_size can be zero to use the default size.
 *
 * Valid flags for ext2fs_open()
 *
 * 	EXT2_FLAG_RW	- Open the filesystem for read/write.
 * 	EXT2_FLAG_FORCE - Open the filesystem even if some of the
 *				features aren't supported.
 *	EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
 *	EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check.
 *	EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large
 *				filesystems)
 */
errcode_t ext2fs_open2(const char *name, const char *io_options,
		       int flags, int superblock,
		       unsigned int block_size, io_manager manager,
		       ext2_filsys *ret_fs)
{
	ext2_filsys	fs;
	errcode_t	retval;
	unsigned long	i, first_meta_bg;
	__u32		features;
	unsigned int	blocks_per_group, io_flags;
	blk64_t		group_block, blk;
	char		*dest, *cp;
	int		group_zero_adjust = 0;
#ifdef WORDS_BIGENDIAN
	unsigned int	groups_per_block;
	struct ext2_group_desc *gdp;
	int		j;
#endif
	char		*time_env;

	EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);

	retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
	if (retval)
		return retval;

	memset(fs, 0, sizeof(struct struct_ext2_filsys));
	fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
	fs->flags = flags;
	/* don't overwrite sb backups unless flag is explicitly cleared */
	fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
	fs->umask = 022;

	time_env = getenv("E2FSPROGS_FAKE_TIME");
	if (time_env)
		fs->now = strtoul(time_env, NULL, 0);

	retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
	if (retval)
		goto cleanup;
	strcpy(fs->device_name, name);
	cp = strchr(fs->device_name, '?');
	if (!io_options && cp) {
		*cp++ = 0;
		io_options = cp;
	}

	io_flags = 0;
	if (flags & EXT2_FLAG_RW)
		io_flags |= IO_FLAG_RW;
	if (flags & EXT2_FLAG_EXCLUSIVE)
		io_flags |= IO_FLAG_EXCLUSIVE;
	if (flags & EXT2_FLAG_DIRECT_IO)
		io_flags |= IO_FLAG_DIRECT_IO;
	retval = manager->open(fs->device_name, io_flags, &fs->io);
	if (retval)
		goto cleanup;
	if (io_options &&
	    (retval = io_channel_set_options(fs->io, io_options)))
		goto cleanup;
	fs->image_io = fs->io;
	fs->io->app_data = fs;
	retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super);
	if (retval)
		goto cleanup;
	if (flags & EXT2_FLAG_IMAGE_FILE) {
		retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
					&fs->image_header);
		if (retval)
			goto cleanup;
		retval = io_channel_read_blk(fs->io, 0,
					     -(int)sizeof(struct ext2_image_hdr),
					     fs->image_header);
		if (retval)
			goto cleanup;
		if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
			return EXT2_ET_MAGIC_E2IMAGE;
		superblock = 1;
		block_size = fs->image_header->fs_blocksize;
	}

	/*
	 * If the user specifies a specific block # for the
	 * superblock, then he/she must also specify the block size!
	 * Otherwise, read the master superblock located at offset
	 * SUPERBLOCK_OFFSET from the start of the partition.
	 *
	 * Note: we only save a backup copy of the superblock if we
	 * are reading the superblock from the primary superblock location.
	 */
	if (superblock) {
		if (!block_size) {
			retval = EXT2_ET_INVALID_ARGUMENT;
			goto cleanup;
		}
		io_channel_set_blksize(fs->io, block_size);
		group_block = superblock;
		fs->orig_super = 0;
	} else {
		io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
		superblock = 1;
		group_block = 0;
		retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
		if (retval)
			goto cleanup;
	}
	retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
				     fs->super);
	if (retval)
		goto cleanup;
	if (fs->orig_super)
		memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);

	if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) {
		retval = 0;
		if (!ext2fs_verify_csum_type(fs, fs->super))
			retval = EXT2_ET_UNKNOWN_CSUM;
		if (!ext2fs_superblock_csum_verify(fs, fs->super))
			retval = EXT2_ET_SB_CSUM_INVALID;
	}

#ifdef WORDS_BIGENDIAN
	fs->flags |= EXT2_FLAG_SWAP_BYTES;
	ext2fs_swap_super(fs->super);
#else
	if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
		retval = EXT2_ET_UNIMPLEMENTED;
		goto cleanup;
	}
#endif

	if (fs->super->s_magic != EXT2_SUPER_MAGIC)
		retval = EXT2_ET_BAD_MAGIC;
	if (retval)
		goto cleanup;

	if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
		retval = EXT2_ET_REV_TOO_HIGH;
		goto cleanup;
	}

	/*
	 * Check for feature set incompatibility
	 */
	if (!(flags & EXT2_FLAG_FORCE)) {
		features = fs->super->s_feature_incompat;
#ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
		if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
			features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT;
#endif
		if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
			retval = EXT2_ET_UNSUPP_FEATURE;
			goto cleanup;
		}

		features = fs->super->s_feature_ro_compat;
#ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
		if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
			features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT;
#endif
		if ((flags & EXT2_FLAG_RW) &&
		    (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
			retval = EXT2_ET_RO_UNSUPP_FEATURE;
			goto cleanup;
		}

		if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
		    ext2fs_has_feature_journal_dev(fs->super)) {
			retval = EXT2_ET_UNSUPP_FEATURE;
			goto cleanup;
		}
	}

	if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) >
	    EXT2_MAX_BLOCK_LOG_SIZE) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}

	/*
	 * bigalloc requires cluster-aware bitfield operations, which at the
	 * moment means we need EXT2_FLAG_64BITS.
	 */
	if (ext2fs_has_feature_bigalloc(fs->super) &&
	    !(flags & EXT2_FLAG_64BITS)) {
		retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS;
		goto cleanup;
	}

	if (!ext2fs_has_feature_bigalloc(fs->super) &&
	    (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}
	fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
	if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}

	/* Enforce the block group descriptor size */
	if (ext2fs_has_feature_64bit(fs->super)) {
		if (fs->super->s_desc_size < EXT2_MIN_DESC_SIZE_64BIT) {
			retval = EXT2_ET_BAD_DESC_SIZE;
			goto cleanup;
		}
	} else {
		if (fs->super->s_desc_size &&
		    fs->super->s_desc_size != EXT2_MIN_DESC_SIZE) {
			retval = EXT2_ET_BAD_DESC_SIZE;
			goto cleanup;
		}
	}

	fs->cluster_ratio_bits = fs->super->s_log_cluster_size -
		fs->super->s_log_block_size;
	if (EXT2_BLOCKS_PER_GROUP(fs->super) !=
	    EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}
	fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
				       EXT2_INODE_SIZE(fs->super) +
				       EXT2_BLOCK_SIZE(fs->super) - 1) /
				      EXT2_BLOCK_SIZE(fs->super));
	if (block_size) {
		if (block_size != fs->blocksize) {
			retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
			goto cleanup;
		}
	}
	/*
	 * Set the blocksize to the filesystem's blocksize.
	 */
	io_channel_set_blksize(fs->io, fs->blocksize);

	/*
	 * If this is an external journal device, don't try to read
	 * the group descriptors, because they're not there.
	 */
	if (ext2fs_has_feature_journal_dev(fs->super)) {
		fs->group_desc_count = 0;
		*ret_fs = fs;
		return 0;
	}

	if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}
	/* Precompute the FS UUID to seed other checksums */
	ext2fs_init_csum_seed(fs);

	/*
	 * Read group descriptors
	 */
	blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
	if (blocks_per_group == 0 ||
	    blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
	    fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
           EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
           fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}
	fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
						 fs->super->s_first_data_block,
						 blocks_per_group);
	if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
	    fs->super->s_inodes_count) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}
	fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
					  EXT2_DESC_PER_BLOCK(fs->super));
	retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
				&fs->group_desc);
	if (retval)
		goto cleanup;
	if (!group_block)
		group_block = fs->super->s_first_data_block;
	/*
	 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders
	 * so we must increment block numbers to any group 0 items.
	 *
	 * However, we cannot touch group_block directly because in the meta_bg
	 * case, the ext2fs_descriptor_block_loc2() function will interpret
	 * group_block != s_first_data_block to mean that we want to access the
	 * backup group descriptors.  This is not what we want if the caller
	 * set superblock == 0 (i.e. auto-detect the superblock), which is
	 * what's going on here.
	 */
	if (group_block == 0 && fs->blocksize == 1024)
		group_zero_adjust = 1;
	dest = (char *) fs->group_desc;
#ifdef WORDS_BIGENDIAN
	groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
#endif
	if (ext2fs_has_feature_meta_bg(fs->super)) {
		first_meta_bg = fs->super->s_first_meta_bg;
		if (first_meta_bg > fs->desc_blocks)
			first_meta_bg = fs->desc_blocks;
	} else
		first_meta_bg = fs->desc_blocks;
	if (first_meta_bg) {
		retval = io_channel_read_blk(fs->io, group_block +
					     group_zero_adjust + 1,
					     first_meta_bg, dest);
		if (retval)
			goto cleanup;
#ifdef WORDS_BIGENDIAN
		gdp = (struct ext2_group_desc *) dest;
		for (j=0; j < groups_per_block*first_meta_bg; j++) {
			gdp = ext2fs_group_desc(fs, fs->group_desc, j);
			ext2fs_swap_group_desc2(fs, gdp);
		}
#endif
		dest += fs->blocksize*first_meta_bg;
	}
	for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
		blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
		retval = io_channel_read_blk64(fs->io, blk, 1, dest);
		if (retval)
			goto cleanup;
#ifdef WORDS_BIGENDIAN
		for (j=0; j < groups_per_block; j++) {
			gdp = ext2fs_group_desc(fs, fs->group_desc,
						i * groups_per_block + j);
			ext2fs_swap_group_desc2(fs, gdp);
		}
#endif
		dest += fs->blocksize;
	}

	fs->stride = fs->super->s_raid_stride;

	/*
	 * If recovery is from backup superblock, Clear _UNININT flags &
	 * reset bg_itable_unused to zero
	 */
	if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) {
		dgrp_t group;

		for (group = 0; group < fs->group_desc_count; group++) {
			ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
			ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
			ext2fs_bg_itable_unused_set(fs, group, 0);
			/* The checksum will be reset later, but fix it here
			 * anyway to avoid printing a lot of spurious errors. */
			ext2fs_group_desc_csum_set(fs, group);
		}
		if (fs->flags & EXT2_FLAG_RW)
			ext2fs_mark_super_dirty(fs);
	}

	if (ext2fs_has_feature_mmp(fs->super) &&
	    !(flags & EXT2_FLAG_SKIP_MMP) &&
	    (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) {
		retval = ext2fs_mmp_start(fs);
		if (retval) {
			fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */
			ext2fs_mmp_stop(fs);
			goto cleanup;
		}
	}

	if (fs->flags & EXT2_FLAG_SHARE_DUP) {
		fs->block_sha_map = ext2fs_hashmap_create(ext2fs_djb2_hash,
					block_sha_map_free_entry, 4096);
		if (!fs->block_sha_map) {
			retval = EXT2_ET_NO_MEMORY;
			goto cleanup;
		}
		ext2fs_set_feature_shared_blocks(fs->super);
	}

	fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
	*ret_fs = fs;

	return 0;
cleanup:
	if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) {
		ext2fs_free(fs);
		fs = NULL;
	}
	*ret_fs = fs;
	return retval;
}
Пример #6
0
static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
{
	dgrp_t i;
	char *block_bitmap = 0, *inode_bitmap = 0;
	char *buf;
	errcode_t retval;
	int block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
	int inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8;
	int csum_flag;
	unsigned int	cnt;
	blk64_t	blk;
	blk64_t	blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
	blk64_t   blk_cnt;
	ext2_ino_t ino_itr = 1;
	ext2_ino_t ino_cnt;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if ((block_nbytes > (int) fs->blocksize) ||
	    (inode_nbytes > (int) fs->blocksize))
		return EXT2_ET_CORRUPT_SUPERBLOCK;

	fs->write_bitmaps = ext2fs_write_bitmaps;

	csum_flag = ext2fs_has_group_desc_csum(fs);

	retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
	if (retval)
		return retval;
	if (do_block) {
		if (fs->block_map)
			ext2fs_free_block_bitmap(fs->block_map);
		strcpy(buf, "block bitmap for ");
		strcat(buf, fs->device_name);
		retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
		if (retval)
			goto cleanup;
		retval = io_channel_alloc_buf(fs->io, 0, &block_bitmap);
		if (retval)
			goto cleanup;
	} else
		block_nbytes = 0;
	if (do_inode) {
		if (fs->inode_map)
			ext2fs_free_inode_bitmap(fs->inode_map);
		strcpy(buf, "inode bitmap for ");
		strcat(buf, fs->device_name);
		retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
		if (retval)
			goto cleanup;
		retval = io_channel_alloc_buf(fs->io, 0, &inode_bitmap);
		if (retval)
			goto cleanup;
	} else
		inode_nbytes = 0;
	ext2fs_free_mem(&buf);

	if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
		blk = (ext2fs_le32_to_cpu(fs->image_header->offset_inodemap) / fs->blocksize);
		ino_cnt = fs->super->s_inodes_count;
		while (inode_bitmap && ino_cnt > 0) {
			retval = io_channel_read_blk64(fs->image_io, blk++,
						     1, inode_bitmap);
			if (retval)
				goto cleanup;
			cnt = fs->blocksize << 3;
			if (cnt > ino_cnt)
				cnt = ino_cnt;
			retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
					       ino_itr, cnt, inode_bitmap);
			if (retval)
				goto cleanup;
			ino_itr += cnt;
			ino_cnt -= cnt;
		}
		blk = (ext2fs_le32_to_cpu(fs->image_header->offset_blockmap) /
		       fs->blocksize);
		blk_cnt = EXT2_GROUPS_TO_CLUSTERS(fs->super,
						  fs->group_desc_count);
		while (block_bitmap && blk_cnt > 0) {
			retval = io_channel_read_blk64(fs->image_io, blk++,
						     1, block_bitmap);
			if (retval)
				goto cleanup;
			cnt = fs->blocksize << 3;
			if (cnt > blk_cnt)
				cnt = blk_cnt;
			retval = ext2fs_set_block_bitmap_range2(fs->block_map,
				       blk_itr, cnt, block_bitmap);
			if (retval)
				goto cleanup;
			blk_itr += cnt;
			blk_cnt -= cnt;
		}
		goto success_cleanup;
	}

	for (i = 0; i < fs->group_desc_count; i++) {
		if (block_bitmap) {
			blk = ext2fs_block_bitmap_loc(fs, i);
			if (csum_flag &&
			    ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT) &&
			    ext2fs_group_desc_csum_verify(fs, i))
				blk = 0;
			if (blk) {
				retval = io_channel_read_blk64(fs->io, blk,
							       1, block_bitmap);
				if (retval) {
					retval = EXT2_ET_BLOCK_BITMAP_READ;
					goto cleanup;
				}
				/* verify block bitmap checksum */
				if (!(fs->flags &
				      EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
				    !ext2fs_block_bitmap_csum_verify(fs, i,
						block_bitmap, block_nbytes)) {
					retval =
					EXT2_ET_BLOCK_BITMAP_CSUM_INVALID;
					goto cleanup;
				}
			} else
				memset(block_bitmap, 0, block_nbytes);
			cnt = block_nbytes << 3;
			retval = ext2fs_set_block_bitmap_range2(fs->block_map,
					       blk_itr, cnt, block_bitmap);
			if (retval)
				goto cleanup;
			blk_itr += block_nbytes << 3;
		}
		if (inode_bitmap) {
			blk = ext2fs_inode_bitmap_loc(fs, i);
			if (csum_flag &&
			    ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT) &&
			    ext2fs_group_desc_csum_verify(fs, i))
				blk = 0;
			if (blk) {
				retval = io_channel_read_blk64(fs->io, blk,
							       1, inode_bitmap);
				if (retval) {
					retval = EXT2_ET_INODE_BITMAP_READ;
					goto cleanup;
				}

				/* verify inode bitmap checksum */
				if (!(fs->flags &
				      EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
				    !ext2fs_inode_bitmap_csum_verify(fs, i,
						inode_bitmap, inode_nbytes)) {
					retval =
					EXT2_ET_INODE_BITMAP_CSUM_INVALID;
					goto cleanup;
				}
			} else
				memset(inode_bitmap, 0, inode_nbytes);
			cnt = inode_nbytes << 3;
			retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
					       ino_itr, cnt, inode_bitmap);
			if (retval)
				goto cleanup;
			ino_itr += inode_nbytes << 3;
		}
	}

	/* Mark group blocks for any BLOCK_UNINIT groups */
	if (do_block) {
		retval = mark_uninit_bg_group_blocks(fs);
		if (retval)
			goto cleanup;
	}

success_cleanup:
	if (inode_bitmap)
		ext2fs_free_mem(&inode_bitmap);
	if (block_bitmap)
		ext2fs_free_mem(&block_bitmap);
	return 0;

cleanup:
	if (do_block) {
		ext2fs_free_mem(&fs->block_map);
		fs->block_map = 0;
	}
	if (do_inode) {
		ext2fs_free_mem(&fs->inode_map);
		fs->inode_map = 0;
	}
	if (inode_bitmap)
		ext2fs_free_mem(&inode_bitmap);
	if (block_bitmap)
		ext2fs_free_mem(&block_bitmap);
	if (buf)
		ext2fs_free_mem(&buf);
	return retval;
}
Пример #7
0
/*
 *  Note: if superblock is non-zero, block-size must also be non-zero.
 * 	Superblock and block_size can be zero to use the default size.
 *
 * Valid flags for ext2fs_open()
 *
 * 	EXT2_FLAG_RW	- Open the filesystem for read/write.
 * 	EXT2_FLAG_FORCE - Open the filesystem even if some of the
 *				features aren't supported.
 *	EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
 *	EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check.
 *	EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large
 *				filesystems)
 */
errcode_t ext2fs_open2(const char *name, const char *io_options,
		       int flags, int superblock,
		       unsigned int block_size, io_channel io,
		       ext2_filsys *ret_fs)
{
	ext2_filsys	fs;
	io_manager manager = io->manager;
	errcode_t	retval;
	unsigned long	i, first_meta_bg;
	__u32		features;
	unsigned int	groups_per_block, blocks_per_group, io_flags;
	blk64_t		group_block, blk;
	char		*dest, *cp;
#ifdef WORDS_BIGENDIAN
	struct ext2_group_desc *gdp;
	int		j;
#endif

	EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);

	retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
	if (retval)
		return retval;

	memset(fs, 0, sizeof(struct struct_ext2_filsys));
	fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
	fs->io = io;
	fs->flags = flags;
	/* don't overwrite sb backups unless flag is explicitly cleared */
	fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
	fs->umask = 022;
	retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
	if (retval)
		goto cleanup;
	strcpy(fs->device_name, name);
	cp = strchr(fs->device_name, '?');
	if (!io_options && cp) {
		*cp++ = 0;
		io_options = cp;
	}

	io_flags = 0;
	if (flags & EXT2_FLAG_RW)
		io_flags |= IO_FLAG_RW;
	if (flags & EXT2_FLAG_EXCLUSIVE)
		io_flags |= IO_FLAG_EXCLUSIVE;
	if (flags & EXT2_FLAG_DIRECT_IO)
		io_flags |= IO_FLAG_DIRECT_IO;
	retval = manager->open(fs->device_name, io_flags, &fs->io);
	if (retval)
		goto cleanup;
	if (io_options &&
	    (retval = io_channel_set_options(fs->io, io_options)))
		goto cleanup;
	fs->image_io = fs->io;
	fs->io->app_data = fs;
	retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super);
	if (retval)
		goto cleanup;
	if (flags & EXT2_FLAG_IMAGE_FILE) {
		retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
					&fs->image_header);
		if (retval)
			goto cleanup;
		retval = io_channel_read_blk(fs->io, 0,
					     -(int)sizeof(struct ext2_image_hdr),
					     fs->image_header);
		if (retval)
			goto cleanup;
		if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
			return EXT2_ET_MAGIC_E2IMAGE;
		superblock = 1;
		block_size = fs->image_header->fs_blocksize;
	}

	/*
	 * If the user specifies a specific block # for the
	 * superblock, then he/she must also specify the block size!
	 * Otherwise, read the master superblock located at offset
	 * SUPERBLOCK_OFFSET from the start of the partition.
	 *
	 * Note: we only save a backup copy of the superblock if we
	 * are reading the superblock from the primary superblock location.
	 */
	if (superblock) {
		if (!block_size) {
			retval = EXT2_ET_INVALID_ARGUMENT;
			goto cleanup;
		}
		io_channel_set_blksize(fs->io, block_size);
		group_block = superblock;
		fs->orig_super = 0;
	} else {
		io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
		superblock = 1;
		group_block = 0;
		retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
		if (retval)
			goto cleanup;
	}
	retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
				     fs->super);
	if (retval)
		goto cleanup;
	if (fs->orig_super)
		memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);

#ifdef WORDS_BIGENDIAN
	fs->flags |= EXT2_FLAG_SWAP_BYTES;
	ext2fs_swap_super(fs->super);
#else
	if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
		retval = EXT2_ET_UNIMPLEMENTED;
		goto cleanup;
	}
#endif

	if (fs->super->s_magic != EXT2_SUPER_MAGIC) {
		retval = EXT2_ET_BAD_MAGIC;
		goto cleanup;
	}
	if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
		retval = EXT2_ET_REV_TOO_HIGH;
		goto cleanup;
	}

	/*
	 * Check for feature set incompatibility
	 */
	if (!(flags & EXT2_FLAG_FORCE)) {
		features = fs->super->s_feature_incompat;
#ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
		if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
			features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT;
#endif
		if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
			retval = EXT2_ET_UNSUPP_FEATURE;
			goto cleanup;
		}

		features = fs->super->s_feature_ro_compat;
#ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
		if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
			features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT;
#endif
		if ((flags & EXT2_FLAG_RW) &&
		    (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
			retval = EXT2_ET_RO_UNSUPP_FEATURE;
			goto cleanup;
		}

		if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
		    (fs->super->s_feature_incompat &
		     EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
			retval = EXT2_ET_UNSUPP_FEATURE;
			goto cleanup;
		}
	}

	if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) >
	    EXT2_MAX_BLOCK_LOG_SIZE) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}
	if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
					EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
	    (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}
	fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
	if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}
	fs->cluster_ratio_bits = fs->super->s_log_cluster_size -
		fs->super->s_log_block_size;
	if (EXT2_BLOCKS_PER_GROUP(fs->super) !=
	    EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}
	fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
				       EXT2_INODE_SIZE(fs->super) +
				       EXT2_BLOCK_SIZE(fs->super) - 1) /
				      EXT2_BLOCK_SIZE(fs->super));
	if (block_size) {
		if (block_size != fs->blocksize) {
			retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
			goto cleanup;
		}
	}
	/*
	 * Set the blocksize to the filesystem's blocksize.
	 */
	io_channel_set_blksize(fs->io, fs->blocksize);

	/*
	 * If this is an external journal device, don't try to read
	 * the group descriptors, because they're not there.
	 */
	if (fs->super->s_feature_incompat &
	    EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
		fs->group_desc_count = 0;
		*ret_fs = fs;
		return 0;
	}

	if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}

	/*
	 * Read group descriptors
	 */
	blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
	if (blocks_per_group == 0 ||
	    blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
	    fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
           EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
           fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}
	fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
						 fs->super->s_first_data_block,
						 blocks_per_group);
	if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
	    fs->super->s_inodes_count) {
		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
		goto cleanup;
	}
	fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
					  EXT2_DESC_PER_BLOCK(fs->super));
	retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
				&fs->group_desc);
	if (retval)
		goto cleanup;
	if (!group_block)
		group_block = fs->super->s_first_data_block;
	if (group_block == 0 && fs->blocksize == 1024)
		group_block = 1; /* Deal with 1024 blocksize && bigalloc */
	dest = (char *) fs->group_desc;
	groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
	if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
		first_meta_bg = fs->super->s_first_meta_bg;
	else
		first_meta_bg = fs->desc_blocks;
	if (first_meta_bg) {
		retval = io_channel_read_blk(fs->io, group_block+1,
					     first_meta_bg, dest);
		if (retval)
			goto cleanup;
#ifdef WORDS_BIGENDIAN
		gdp = (struct ext2_group_desc *) dest;
		for (j=0; j < groups_per_block*first_meta_bg; j++) {
			gdp = ext2fs_group_desc(fs, fs->group_desc, j);
			ext2fs_swap_group_desc2(fs, gdp);
		}
#endif
		dest += fs->blocksize*first_meta_bg;
	}
	for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
		blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
		retval = io_channel_read_blk64(fs->io, blk, 1, dest);
		if (retval)
			goto cleanup;
#ifdef WORDS_BIGENDIAN
		for (j=0; j < groups_per_block; j++) {
			gdp = ext2fs_group_desc(fs, fs->group_desc,
						i * groups_per_block + j);
			ext2fs_swap_group_desc2(fs, gdp);
		}
#endif
		dest += fs->blocksize;
	}

	fs->stride = fs->super->s_raid_stride;

	/*
	 * If recovery is from backup superblock, Clear _UNININT flags &
	 * reset bg_itable_unused to zero
	 */
	if (superblock > 1 && EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
					EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
		dgrp_t group;

		for (group = 0; group < fs->group_desc_count; group++) {
			ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
			ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
			ext2fs_bg_itable_unused_set(fs, group, 0);
			/* The checksum will be reset later, but fix it here
			 * anyway to avoid printing a lot of spurious errors. */
			ext2fs_group_desc_csum_set(fs, group);
		}
		if (fs->flags & EXT2_FLAG_RW)
			ext2fs_mark_super_dirty(fs);
	}

	fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
	*ret_fs = fs;

	if ((fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_MMP) &&
	    !(flags & EXT2_FLAG_SKIP_MMP) &&
	    (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) {
		retval = ext2fs_mmp_start(fs);
		if (retval) {
			fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */
			ext2fs_mmp_stop(fs);
			goto cleanup;
		}
	}

	return 0;
cleanup:
	if (flags & EXT2_FLAG_NOFREE_ON_ERROR)
		*ret_fs = fs;
	else
		ext2fs_free(fs);
	return retval;
}