misc/e2image.c

/*
 * e2image.c --- Program which writes an image file backing up
 * critical metadata for the filesystem.
 *
 * Copyright 2000, 2001 by Theodore Ts'o.
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Public
 * License.
 * %End-Header%
 */

#define _LARGEFILE_SOURCE
#define _LARGEFILE64_SOURCE

#include "config.h"
#include <fcntl.h>
#include <grp.h>
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#else
extern char *optarg;
extern int optind;
#endif
#include <pwd.h>
#include <stdio.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <assert.h>

#include "ext2fs/ext2_fs.h"
#include "ext2fs/ext2fs.h"
#include "et/com_err.h"
#include "uuid/uuid.h"
#include "e2p/e2p.h"
#include "ext2fs/e2image.h"
#include "ext2fs/qcow2.h"

#include "../version.h"
#include "nls-enable.h"

#define QCOW_OFLAG_COPIED     (1LL << 63)


const char * program_name = "e2image";
char * device_name = NULL;

static void lseek_error_and_exit(int errnum)
{
	fprintf(stderr, "seek: %s\n", error_message(errnum));
	exit(1);
}

static blk64_t align_offset(blk64_t offset, int n)
{
	return (offset + n - 1) & ~(n - 1);
}

static int get_bits_from_size(size_t size)
{
	int res = 0;

	if (size == 0)
		return -1;

	while (size != 1) {
		/* Not a power of two */
		if (size & 1)
			return -1;

		size >>= 1;
		res++;
	}
	return res;
}

static void usage(void)
{
	fprintf(stderr, _("Usage: %s [-rsIQ] device image_file\n"),
		program_name);
	exit (1);
}

static void generic_write(int fd, void *buf, int blocksize, blk64_t block)
{
	int count, free_buf = 0;
	errcode_t err;

	if (!blocksize)
		return;

	if (!buf) {
		free_buf = 1;
		err = ext2fs_get_arrayzero(1, blocksize, &buf);
		if (err) {
			com_err(program_name, err, "while allocating buffer");
			exit(1);
		}
	}

	count = write(fd, buf, blocksize);
	if (count != blocksize) {
		if (count == -1)
			err = errno;
		else
			err = 0;

		if (block)
			com_err(program_name, err, "error writing block %llu",
				block);
		else
			com_err(program_name, err, "error in write()");

		exit(1);
	}
	if (free_buf)
		ext2fs_free_mem(&buf);
}

static void write_header(int fd, void *hdr, int hdr_size, int wrt_size)
{
	char *header_buf;
	int ret;

	/* Sanity check */
	if (hdr_size > wrt_size) {
		fprintf(stderr, _("Error: header size is bigger than "
				  "wrt_size\n"));
	}

	ret = ext2fs_get_mem(wrt_size, &header_buf);
	if (ret) {
		fputs(_("Couldn't allocate header buffer\n"), stderr);
		exit(1);
	}

	if (ext2fs_llseek(fd, 0, SEEK_SET) < 0) {
		perror("ext2fs_llseek while writing header");
		exit(1);
	}
	memset(header_buf, 0, wrt_size);

	if (hdr)
		memcpy(header_buf, hdr, hdr_size);

	generic_write(fd, header_buf, wrt_size, 0);

	ext2fs_free_mem(&header_buf);
}

static void write_image_file(ext2_filsys fs, int fd)
{
	struct ext2_image_hdr	hdr;
	struct stat		st;
	errcode_t		retval;

	write_header(fd, NULL, fs->blocksize, fs->blocksize);
	memset(&hdr, 0, sizeof(struct ext2_image_hdr));

	hdr.offset_super = ext2fs_llseek(fd, 0, SEEK_CUR);
	retval = ext2fs_image_super_write(fs, fd, 0);
	if (retval) {
		com_err(program_name, retval, _("while writing superblock"));
		exit(1);
	}

	hdr.offset_inode = ext2fs_llseek(fd, 0, SEEK_CUR);
	retval = ext2fs_image_inode_write(fs, fd,
				  (fd != 1) ? IMAGER_FLAG_SPARSEWRITE : 0);
	if (retval) {
		com_err(program_name, retval, _("while writing inode table"));
		exit(1);
	}

	hdr.offset_blockmap = ext2fs_llseek(fd, 0, SEEK_CUR);
	retval = ext2fs_image_bitmap_write(fs, fd, 0);
	if (retval) {
		com_err(program_name, retval, _("while writing block bitmap"));
		exit(1);
	}

	hdr.offset_inodemap = ext2fs_llseek(fd, 0, SEEK_CUR);
	retval = ext2fs_image_bitmap_write(fs, fd, IMAGER_FLAG_INODEMAP);
	if (retval) {
		com_err(program_name, retval, _("while writing inode bitmap"));
		exit(1);
	}

	hdr.magic_number = EXT2_ET_MAGIC_E2IMAGE;
	strcpy(hdr.magic_descriptor, "Ext2 Image 1.0");
	gethostname(hdr.fs_hostname, sizeof(hdr.fs_hostname));
	strncpy(hdr.fs_device_name, device_name, sizeof(hdr.fs_device_name)-1);
	hdr.fs_device_name[sizeof(hdr.fs_device_name) - 1] = 0;
	hdr.fs_blocksize = fs->blocksize;

	if (stat(device_name, &st) == 0)
		hdr.fs_device = st.st_rdev;

	if (fstat(fd, &st) == 0) {
		hdr.image_device = st.st_dev;
		hdr.image_inode = st.st_ino;
	}
	memcpy(hdr.fs_uuid, fs->super->s_uuid, sizeof(hdr.fs_uuid));

	hdr.image_time = time(0);
	write_header(fd, &hdr, fs->blocksize, fs->blocksize);
}

/*
 * These set of functions are used to write a RAW image file.
 */
ext2fs_block_bitmap meta_block_map;
ext2fs_block_bitmap scramble_block_map;	/* Directory blocks to be scrambled */
blk64_t meta_blocks_count;

struct process_block_struct {
	ext2_ino_t	ino;
	int		is_dir;
};

/*
 * These subroutines short circuits ext2fs_get_blocks and
 * ext2fs_check_directory; we use them since we already have the inode
 * structure, so there's no point in letting the ext2fs library read
 * the inode again.
 */
static ino_t stashed_ino = 0;
static struct ext2_inode *stashed_inode;

static errcode_t meta_get_blocks(ext2_filsys fs EXT2FS_ATTR((unused)),
				 ext2_ino_t ino,
				 blk_t *blocks)
{
	int	i;

	if ((ino != stashed_ino) || !stashed_inode)
		return EXT2_ET_CALLBACK_NOTHANDLED;

	for (i=0; i < EXT2_N_BLOCKS; i++)
		blocks[i] = stashed_inode->i_block[i];
	return 0;
}

static errcode_t meta_check_directory(ext2_filsys fs EXT2FS_ATTR((unused)),
				      ext2_ino_t ino)
{
	if ((ino != stashed_ino) || !stashed_inode)
		return EXT2_ET_CALLBACK_NOTHANDLED;

	if (!LINUX_S_ISDIR(stashed_inode->i_mode))
		return EXT2_ET_NO_DIRECTORY;
	return 0;
}

static errcode_t meta_read_inode(ext2_filsys fs EXT2FS_ATTR((unused)),
				 ext2_ino_t ino,
				 struct ext2_inode *inode)
{
	if ((ino != stashed_ino) || !stashed_inode)
		return EXT2_ET_CALLBACK_NOTHANDLED;
	*inode = *stashed_inode;
	return 0;
}

static void use_inode_shortcuts(ext2_filsys fs, int bool)
{
	if (bool) {
		fs->get_blocks = meta_get_blocks;
		fs->check_directory = meta_check_directory;
		fs->read_inode = meta_read_inode;
		stashed_ino = 0;
	} else {
		fs->get_blocks = 0;
		fs->check_directory = 0;
		fs->read_inode = 0;
	}
}

static int process_dir_block(ext2_filsys fs EXT2FS_ATTR((unused)),
			     blk64_t *block_nr,
			     e2_blkcnt_t blockcnt EXT2FS_ATTR((unused)),
			     blk64_t ref_block EXT2FS_ATTR((unused)),
			     int ref_offset EXT2FS_ATTR((unused)),
			     void *priv_data EXT2FS_ATTR((unused)))
{
	struct process_block_struct *p;

	p = (struct process_block_struct *) priv_data;

	ext2fs_mark_block_bitmap2(meta_block_map, *block_nr);
	meta_blocks_count++;
	if (scramble_block_map && p->is_dir && blockcnt >= 0)
		ext2fs_mark_block_bitmap2(scramble_block_map, *block_nr);
	return 0;
}

static int process_file_block(ext2_filsys fs EXT2FS_ATTR((unused)),
			      blk64_t *block_nr,
			      e2_blkcnt_t blockcnt,
			      blk64_t ref_block EXT2FS_ATTR((unused)),
			      int ref_offset EXT2FS_ATTR((unused)),
			      void *priv_data EXT2FS_ATTR((unused)))
{
	if (blockcnt < 0) {
		ext2fs_mark_block_bitmap2(meta_block_map, *block_nr);
		meta_blocks_count++;
	}
	return 0;
}

static void mark_table_blocks(ext2_filsys fs)
{
	blk64_t	first_block, b;
	unsigned int	i,j;

	first_block = fs->super->s_first_data_block;
	/*
	 * Mark primary superblock
	 */
	ext2fs_mark_block_bitmap2(meta_block_map, first_block);
	meta_blocks_count++;

	/*
	 * Mark the primary superblock descriptors
	 */
	for (j = 0; j < fs->desc_blocks; j++) {
		ext2fs_mark_block_bitmap2(meta_block_map,
			 ext2fs_descriptor_block_loc2(fs, first_block, j));
	}
	meta_blocks_count += fs->desc_blocks;

	for (i = 0; i < fs->group_desc_count; i++) {
		/*
		 * Mark the blocks used for the inode table
		 */
		if (!ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT) &&
		    ext2fs_inode_table_loc(fs, i)) {
			unsigned int end = (unsigned) fs->inode_blocks_per_group;
			/* skip unused blocks */
			if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
						       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
				end -= (ext2fs_bg_itable_unused(fs, i) /
					EXT2_INODES_PER_BLOCK(fs->super));
			for (j = 0, b = ext2fs_inode_table_loc(fs, i);
			     j < end;
			     j++, b++) {
				ext2fs_mark_block_bitmap2(meta_block_map, b);
				meta_blocks_count++;
			}
		}

		/*
		 * Mark block used for the block bitmap
		 */
		if (!ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT) &&
		    ext2fs_block_bitmap_loc(fs, i)) {
			ext2fs_mark_block_bitmap2(meta_block_map,
				     ext2fs_block_bitmap_loc(fs, i));
			meta_blocks_count++;
		}

		/*
		 * Mark block used for the inode bitmap
		 */
		if (!ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT) &&
		    ext2fs_inode_bitmap_loc(fs, i)) {
			ext2fs_mark_block_bitmap2(meta_block_map,
				 ext2fs_inode_bitmap_loc(fs, i));
			meta_blocks_count++;
		}
	}
}

/*
 * This function returns 1 if the specified block is all zeros
 */
static int check_zero_block(char *buf, int blocksize)
{
	char	*cp = buf;
	int	left = blocksize;

	while (left > 0) {
		if (*cp++)
			return 0;
		left--;
	}
	return 1;
}

static void write_block(int fd, char *buf, int sparse_offset,
			int blocksize, blk64_t block)
{
	ext2_loff_t	ret = 0;

	if (sparse_offset)
		ret = ext2fs_llseek(fd, sparse_offset, SEEK_CUR);

	if (ret < 0)
		lseek_error_and_exit(errno);
	generic_write(fd, buf, blocksize, block);
}

int name_id[256];

#define EXT4_MAX_REC_LEN		((1<<16)-1)

static void scramble_dir_block(ext2_filsys fs, blk64_t blk, char *buf)
{
	char *p, *end, *cp;
	struct ext2_dir_entry_2 *dirent;
	unsigned int rec_len;
	int id, len;

	end = buf + fs->blocksize;
	for (p = buf; p < end-8; p += rec_len) {
		dirent = (struct ext2_dir_entry_2 *) p;
		rec_len = dirent->rec_len;
#ifdef WORDS_BIGENDIAN
		rec_len = ext2fs_swab16(rec_len);
#endif
		if (rec_len == EXT4_MAX_REC_LEN || rec_len == 0)
			rec_len = fs->blocksize;
		else 
			rec_len = (rec_len & 65532) | ((rec_len & 3) << 16);
#if 0
		printf("rec_len = %d, name_len = %d\n", rec_len, dirent->name_len);
#endif
		if (rec_len < 8 || (rec_len % 4) ||
		    (p+rec_len > end)) {
			printf("Corrupt directory block %lu: "
			       "bad rec_len (%d)\n", (unsigned long) blk,
			       rec_len);
			rec_len = end - p;
			(void) ext2fs_set_rec_len(fs, rec_len,
					(struct ext2_dir_entry *) dirent);
#ifdef WORDS_BIGENDIAN
			dirent->rec_len = ext2fs_swab16(dirent->rec_len);
#endif
			continue;
		}
		if (dirent->name_len + 8 > rec_len) {
			printf("Corrupt directory block %lu: "
			       "bad name_len (%d)\n", (unsigned long) blk,
			       dirent->name_len);
			dirent->name_len = rec_len - 8;
			continue;
		}
		cp = p+8;
		len = rec_len - dirent->name_len - 8;
		if (len > 0)
			memset(cp+dirent->name_len, 0, len);
		if (dirent->name_len==1 && cp[0] == '.')
			continue;
		if (dirent->name_len==2 && cp[0] == '.' && cp[1] == '.')
			continue;

		memset(cp, 'A', dirent->name_len);
		len = dirent->name_len;
		id = name_id[len]++;
		while ((len > 0) && (id > 0)) {
			*cp += id % 26;
			id = id / 26;
			cp++;
			len--;
		}
	}
}

static void output_meta_data_blocks(ext2_filsys fs, int fd)
{
	errcode_t	retval;
	blk64_t		blk;
	char		*buf, *zero_buf;
	int		sparse = 0;

	retval = ext2fs_get_mem(fs->blocksize, &buf);
	if (retval) {
		com_err(program_name, retval, "while allocating buffer");
		exit(1);
	}
	retval = ext2fs_get_memzero(fs->blocksize, &zero_buf);
	if (retval) {
		com_err(program_name, retval, "while allocating buffer");
		exit(1);
	}
	for (blk = 0; blk < ext2fs_blocks_count(fs->super); blk++) {
		if ((blk >= fs->super->s_first_data_block) &&
		    ext2fs_test_block_bitmap2(meta_block_map, blk)) {
			retval = io_channel_read_blk64(fs->io, blk, 1, buf);
			if (retval) {
				com_err(program_name, retval,
					"error reading block %llu", blk);
			}
			if (scramble_block_map &&
			    ext2fs_test_block_bitmap2(scramble_block_map, blk))
				scramble_dir_block(fs, blk, buf);
			if ((fd != 1) && check_zero_block(buf, fs->blocksize))
				goto sparse_write;
			write_block(fd, buf, sparse, fs->blocksize, blk);
			sparse = 0;
		} else {
		sparse_write:
			if (fd == 1) {
				write_block(fd, zero_buf, 0,
					    fs->blocksize, blk);
				continue;
			}
			sparse += fs->blocksize;
			if (sparse > 1024*1024) {
				write_block(fd, 0, 1024*1024, 0, 0);
				sparse -= 1024*1024;
			}
		}
	}
#ifdef HAVE_FTRUNCATE64
	if (sparse) {
		ext2_loff_t offset = ext2fs_llseek(fd, sparse, SEEK_CUR);

		if (offset < 0)
			lseek_error_and_exit(errno);
		if (ftruncate64(fd, offset) < 0)
			write_block(fd, zero_buf, -1, 1, -1);
	}
#else
	if (sparse)
		write_block(fd, zero_buf, sparse-1, 1, -1);
#endif
	ext2fs_free_mem(&zero_buf);
	ext2fs_free_mem(&buf);
}

static void init_l1_table(struct ext2_qcow2_image *image)
{
	__u64 *l1_table;
	errcode_t ret;

	ret = ext2fs_get_arrayzero(image->l1_size, sizeof(__u64), &l1_table);
	if (ret) {
		com_err(program_name, ret, "while allocating l1 table");
		exit(1);
	}

	image->l1_table = l1_table;
}

static void init_l2_cache(struct ext2_qcow2_image *image)
{
	unsigned int count, i;
	struct ext2_qcow2_l2_cache *cache;
	struct ext2_qcow2_l2_table *table;
	errcode_t ret;

	ret = ext2fs_get_arrayzero(1, sizeof(struct ext2_qcow2_l2_cache),
				   &cache);
	if (ret)
		goto alloc_err;

	count = (image->l1_size > L2_CACHE_PREALLOC) ? L2_CACHE_PREALLOC :
		 image->l1_size;

	cache->count = count;
	cache->free = count;
	cache->next_offset = image->l2_offset;

	for (i = 0; i < count; i++) {
		ret = ext2fs_get_arrayzero(1,
				sizeof(struct ext2_qcow2_l2_table), &table);
		if (ret)
			goto alloc_err;

		ret = ext2fs_get_arrayzero(image->l2_size,
						   sizeof(__u64), &table->data);
		if (ret)
			goto alloc_err;

		table->next = cache->free_head;
		cache->free_head = table;
	}

	image->l2_cache = cache;
	return;

alloc_err:
	com_err(program_name, ret, "while allocating l2 cache");
	exit(1);
}

static void put_l2_cache(struct ext2_qcow2_image *image)
{
	struct ext2_qcow2_l2_cache *cache = image->l2_cache;
	struct ext2_qcow2_l2_table *tmp, *table;

	if (!cache)
		return;

	table = cache->free_head;
	cache->free_head = NULL;
again:
	while (table) {
		tmp = table;
		table = table->next;
		ext2fs_free_mem(&tmp->data);
		ext2fs_free_mem(&tmp);
	}

	if (cache->free != cache->count) {
		fprintf(stderr, "Warning: There are still tables in the "
				"cache while putting the cache, data will "
				"be lost so the image may not be valid.\n");
		table = cache->used_head;
		cache->used_head = NULL;
		goto again;
	}

	ext2fs_free_mem(&cache);
}

static int init_refcount(struct ext2_qcow2_image *img, blk64_t table_offset)
{
	struct	ext2_qcow2_refcount	*ref;
	blk64_t table_clusters;
	errcode_t ret;

	ref = &(img->refcount);

	/*
	 * One refcount block addresses 2048 clusters, one refcount table
	 * addresses cluster/sizeof(__u64) refcount blocks, and we need
	 * to address meta_blocks_count clusters + qcow2 metadata clusters
	 * in the worst case.
	 */
	table_clusters = meta_blocks_count + (table_offset >>
					      img->cluster_bits);
	table_clusters >>= (img->cluster_bits + 6 - 1);
	table_clusters = (table_clusters == 0) ? 1 : table_clusters;

	ref->refcount_table_offset = table_offset;
	ref->refcount_table_clusters = table_clusters;
	ref->refcount_table_index = 0;
	ref->refcount_block_index = 0;

	/* Allocate refcount table */
	ret = ext2fs_get_arrayzero(ref->refcount_table_clusters,
				   img->cluster_size, &ref->refcount_table);
	if (ret)
		return ret;

	/* Allocate refcount block */
	ret = ext2fs_get_arrayzero(1, img->cluster_size, &ref->refcount_block);
	if (ret)
		ext2fs_free_mem(&ref->refcount_table);

	return ret;
}

static int initialize_qcow2_image(int fd, ext2_filsys fs,
			    struct ext2_qcow2_image *image)
{
	struct ext2_qcow2_hdr *header;
	blk64_t total_size, offset;
	int shift, l2_bits, header_size, l1_size, ret;
	int cluster_bits = get_bits_from_size(fs->blocksize);
	struct ext2_super_block *sb = fs->super;

	/* Allocate header */
	ret = ext2fs_get_memzero(sizeof(struct ext2_qcow2_hdr), &header);
	if (ret)
		return ret;

	total_size = ext2fs_blocks_count(sb) << cluster_bits;
	image->cluster_size = fs->blocksize;
	image->l2_size = 1 << (cluster_bits - 3);
	image->cluster_bits = cluster_bits;
	image->fd = fd;

	header->magic = ext2fs_cpu_to_be32(QCOW_MAGIC);
	header->version = ext2fs_cpu_to_be32(QCOW_VERSION);
	header->size = ext2fs_cpu_to_be64(total_size);
	header->cluster_bits = ext2fs_cpu_to_be32(cluster_bits);

	header_size = (sizeof(struct ext2_qcow2_hdr) + 7) & ~7;
	offset = align_offset(header_size, image->cluster_size);

	header->l1_table_offset = ext2fs_cpu_to_be64(offset);
	image->l1_offset = offset;

	l2_bits = cluster_bits - 3;
	shift = cluster_bits + l2_bits;
	l1_size = ((total_size + (1LL << shift) - 1) >> shift);
	header->l1_size = ext2fs_cpu_to_be32(l1_size);
	image->l1_size = l1_size;

	/* Make space for L1 table */
	offset += align_offset(l1_size * sizeof(blk64_t), image->cluster_size);

	/* Initialize refcounting */
	ret = init_refcount(image, offset);
	if (ret) {
		ext2fs_free_mem(&header);
		return ret;
	}
	header->refcount_table_offset = ext2fs_cpu_to_be64(offset);
	header->refcount_table_clusters =
		ext2fs_cpu_to_be32(image->refcount.refcount_table_clusters);
	offset += image->cluster_size;
	offset += image->refcount.refcount_table_clusters <<
		image->cluster_bits;

	/* Make space for L2 tables */
	image->l2_offset = offset;
	offset += image->cluster_size;

	/* Make space for first refcount block */
	image->refcount.refcount_block_offset = offset;

	image->hdr = header;
	/* Initialize l1 and l2 tables */
	init_l1_table(image);
	init_l2_cache(image);

	return 0;
}

static void free_qcow2_image(struct ext2_qcow2_image *img)
{
	if (!img)
		return;

	if (img->hdr)
		ext2fs_free_mem(&img->hdr);

	if (img->l1_table)
		ext2fs_free_mem(&img->l1_table);

	if (img->refcount.refcount_table)
		ext2fs_free_mem(&img->refcount.refcount_table);
	if (img->refcount.refcount_block)
		ext2fs_free_mem(&img->refcount.refcount_block);

	put_l2_cache(img);

	ext2fs_free_mem(&img);
}

/**
 * Put table from used list (used_head) into free list (free_head).
 * l2_table is used to return pointer to the next used table (used_head).
 */
static void put_used_table(struct ext2_qcow2_image *img,
			  struct ext2_qcow2_l2_table **l2_table)
{
	struct ext2_qcow2_l2_cache *cache = img->l2_cache;
	struct ext2_qcow2_l2_table *table;

	table = cache->used_head;
	cache->used_head = table->next;

	assert(table);
	if (!table->next)
		cache->used_tail = NULL;

	/* Clean the table for case we will need to use it again */
	memset(table->data, 0, img->cluster_size);
	table->next = cache->free_head;
	cache->free_head = table;

	cache->free++;

	*l2_table = cache->used_head;
}

static void flush_l2_cache(struct ext2_qcow2_image *image)
{
	blk64_t seek = 0;
	ext2_loff_t offset;
	struct ext2_qcow2_l2_cache *cache = image->l2_cache;
	struct ext2_qcow2_l2_table *table = cache->used_head;
	int fd = image->fd;

	/* Store current position */
	if ((offset = ext2fs_llseek(fd, 0, SEEK_CUR)) < 0)
		lseek_error_and_exit(errno);

	assert(table);
	while (cache->free < cache->count) {
		if (seek != table->offset) {
			if (ext2fs_llseek(fd, table->offset, SEEK_SET) < 0)
				lseek_error_and_exit(errno);
			seek = table->offset;
		}

		generic_write(fd, (char *)table->data, image->cluster_size , 0);
		put_used_table(image, &table);
		seek += image->cluster_size;
	}

	/* Restore previous position */
	if (ext2fs_llseek(fd, offset, SEEK_SET) < 0)
		lseek_error_and_exit(errno);
}

/**
 * Get first free table (from free_head) and put it into tail of used list
 * (to used_tail).
 * l2_table is used to return pointer to moved table.
 * Returns 1 if the cache is full, 0 otherwise.
 */
static void get_free_table(struct ext2_qcow2_image *image,
			  struct ext2_qcow2_l2_table **l2_table)
{
	struct ext2_qcow2_l2_table *table;
	struct ext2_qcow2_l2_cache *cache = image->l2_cache;

	if (0 == cache->free)
		flush_l2_cache(image);

	table = cache->free_head;
	assert(table);
	cache->free_head = table->next;

	if (cache->used_tail)
		cache->used_tail->next = table;
	else
		/* First item in the used list */
		cache->used_head = table;

	cache->used_tail = table;
	cache->free--;

	*l2_table = table;
}

static int add_l2_item(struct ext2_qcow2_image *img, blk64_t blk,
		       blk64_t data, blk64_t next)
{
	struct ext2_qcow2_l2_cache *cache = img->l2_cache;
	struct ext2_qcow2_l2_table *table = cache->used_tail;
	blk64_t l1_index = blk / img->l2_size;
	blk64_t l2_index = blk & (img->l2_size - 1);
	int ret = 0;

	/*
	 * Need to create new table if it does not exist,
	 * or if it is full
	 */
	if (!table || (table->l1_index != l1_index)) {
		get_free_table(img, &table);
		table->l1_index = l1_index;
		table->offset = cache->next_offset;
		cache->next_offset = next;
		img->l1_table[l1_index] =
			ext2fs_cpu_to_be64(table->offset | QCOW_OFLAG_COPIED);
		ret++;
	}

	table->data[l2_index] = ext2fs_cpu_to_be64(data | QCOW_OFLAG_COPIED);
	return ret;
}

static int update_refcount(int fd, struct ext2_qcow2_image *img,
			   blk64_t offset, blk64_t rfblk_pos)
{
	struct	ext2_qcow2_refcount	*ref;
	__u32	table_index;
	int ret = 0;

	ref = &(img->refcount);
	table_index = offset >> (2 * img->cluster_bits - 1);

	/*
	 * Need to create new refcount block when the offset addresses
	 * another item in the refcount table
	 */
	if (table_index != ref->refcount_table_index) {

		if (ext2fs_llseek(fd, ref->refcount_block_offset, SEEK_SET) < 0)
			lseek_error_and_exit(errno);

		generic_write(fd, (char *)ref->refcount_block,
			      img->cluster_size, 0);
		memset(ref->refcount_block, 0, img->cluster_size);

		ref->refcount_table[ref->refcount_table_index] =
			ext2fs_cpu_to_be64(ref->refcount_block_offset);
		ref->refcount_block_offset = rfblk_pos;
		ref->refcount_block_index = 0;
		ref->refcount_table_index = table_index;
		ret++;
	}

	/*
	 * We are relying on the fact that we are creating the qcow2
	 * image sequentially, hence we will always allocate refcount
	 * block items sequentialy.
	 */
	ref->refcount_block[ref->refcount_block_index] = ext2fs_cpu_to_be16(1);
	ref->refcount_block_index++;
	return ret;
}

static int sync_refcount(int fd, struct ext2_qcow2_image *img)
{
	struct	ext2_qcow2_refcount	*ref;

	ref = &(img->refcount);

	ref->refcount_table[ref->refcount_table_index] =
		ext2fs_cpu_to_be64(ref->refcount_block_offset);
	if (ext2fs_llseek(fd, ref->refcount_table_offset, SEEK_SET) < 0)
		lseek_error_and_exit(errno);
	generic_write(fd, (char *)ref->refcount_table,
		ref->refcount_table_clusters << img->cluster_bits, 0);

	if (ext2fs_llseek(fd, ref->refcount_block_offset, SEEK_SET) < 0)
		lseek_error_and_exit(errno);
	generic_write(fd, (char *)ref->refcount_block, img->cluster_size, 0);
	return 0;
}

static void output_qcow2_meta_data_blocks(ext2_filsys fs, int fd)
{
	errcode_t		retval;
	blk64_t			blk, offset, size, end;
	char			*buf;
	struct ext2_qcow2_image	*img;
	unsigned int		header_size;

	/* allocate  struct ext2_qcow2_image */
	retval = ext2fs_get_mem(sizeof(struct ext2_qcow2_image), &img);
	if (retval) {
		com_err(program_name, retval,
			"while allocating ext2_qcow2_image");
		exit(1);
	}

	retval = initialize_qcow2_image(fd, fs, img);
	if (retval) {
		com_err(program_name, retval,
			"while initializing ext2_qcow2_image");
		exit(1);
	}
	header_size = align_offset(sizeof(struct ext2_qcow2_hdr),
				   img->cluster_size);
	write_header(fd, img->hdr, sizeof(struct ext2_qcow2_hdr), header_size);

	/* Refcount all qcow2 related metadata up to refcount_block_offset */
	end = img->refcount.refcount_block_offset;
	if (ext2fs_llseek(fd, end, SEEK_SET) < 0)
		lseek_error_and_exit(errno);
	blk = end + img->cluster_size;
	for (offset = 0; offset <= end; offset += img->cluster_size) {
		if (update_refcount(fd, img, offset, blk)) {
			blk += img->cluster_size;
			/*
			 * If we create new refcount block, we need to refcount
			 * it as well.
			 */
			end += img->cluster_size;
		}
	}
	if (ext2fs_llseek(fd, offset, SEEK_SET) < 0)
		lseek_error_and_exit(errno);

	retval = ext2fs_get_mem(fs->blocksize, &buf);
	if (retval) {
		com_err(program_name, retval, "while allocating buffer");
		exit(1);
	}
	/* Write qcow2 data blocks */
	for (blk = 0; blk < ext2fs_blocks_count(fs->super); blk++) {
		if ((blk >= fs->super->s_first_data_block) &&
		    ext2fs_test_block_bitmap2(meta_block_map, blk)) {
			retval = io_channel_read_blk64(fs->io, blk, 1, buf);
			if (retval) {
				com_err(program_name, retval,
					"error reading block %llu", blk);
				continue;
			}
			if (scramble_block_map &&
			    ext2fs_test_block_bitmap2(scramble_block_map, blk))
				scramble_dir_block(fs, blk, buf);
			if (check_zero_block(buf, fs->blocksize))
				continue;

			if (update_refcount(fd, img, offset, offset)) {
				/* Make space for another refcount block */
				offset += img->cluster_size;
				if (ext2fs_llseek(fd, offset, SEEK_SET) < 0)
					lseek_error_and_exit(errno);
				/*
				 * We have created the new refcount block, this
				 * means that we need to refcount it as well.
				 * So the previous update_refcount refcounted
				 * the block itself and now we are going to
				 * create refcount for data. New refcount
				 * block should not be created!
				 */
				if (update_refcount(fd, img, offset, offset)) {
					fprintf(stderr, "Programming error: "
						"multiple sequential refcount "
						"blocks created!\n");
					exit(1);
				}
			}

			generic_write(fd, buf, fs->blocksize, 0);

			if (add_l2_item(img, blk, offset,
					offset + img->cluster_size)) {
				offset += img->cluster_size;
				if (update_refcount(fd, img, offset,
					offset + img->cluster_size)) {
					offset += img->cluster_size;
					if (update_refcount(fd, img, offset,
							    offset)) {
						fprintf(stderr,
			"Programming error: multiple sequential refcount "
			"blocks created!\n");
						exit(1);
					}
				}
				offset += img->cluster_size;
				if (ext2fs_llseek(fd, offset, SEEK_SET) < 0)
					lseek_error_and_exit(errno);
				continue;
			}

			offset += img->cluster_size;
		}
	}
	update_refcount(fd, img, offset, offset);
	flush_l2_cache(img);
	sync_refcount(fd, img);

	/* Write l1_table*/
	if (ext2fs_llseek(fd, img->l1_offset, SEEK_SET) < 0)
		lseek_error_and_exit(errno);
	size = img->l1_size * sizeof(__u64);
	generic_write(fd, (char *)img->l1_table, size, 0);

	ext2fs_free_mem(&buf);
	free_qcow2_image(img);
}

static void write_raw_image_file(ext2_filsys fs, int fd, int type, int flags)
{
	struct process_block_struct	pb;
	struct ext2_inode		inode;
	ext2_inode_scan			scan;
	ext2_ino_t			ino;
	errcode_t			retval;
	char *				block_buf;

	meta_blocks_count = 0;
	retval = ext2fs_allocate_block_bitmap(fs, "in-use block map",
					      &meta_block_map);
	if (retval) {
		com_err(program_name, retval, "while allocating block bitmap");
		exit(1);
	}

	if (flags & E2IMAGE_SCRAMBLE_FLAG) {
		retval = ext2fs_allocate_block_bitmap(fs, "scramble block map",
						      &scramble_block_map);
		if (retval) {
			com_err(program_name, retval,
				"while allocating scramble block bitmap");
			exit(1);
		}
	}

	mark_table_blocks(fs);

	retval = ext2fs_open_inode_scan(fs, 0, &scan);
	if (retval) {
		com_err(program_name, retval, _("while opening inode scan"));
		exit(1);
	}

	retval = ext2fs_get_mem(fs->blocksize * 3, &block_buf);
	if (retval) {
		com_err(program_name, 0, "Can't allocate block buffer");
		exit(1);
	}

	use_inode_shortcuts(fs, 1);
	stashed_inode = &inode;
	while (1) {
		retval = ext2fs_get_next_inode(scan, &ino, &inode);
		if (retval == EXT2_ET_BAD_BLOCK_IN_INODE_TABLE)
			continue;
		if (retval) {
			com_err(program_name, retval,
				_("while getting next inode"));
			exit(1);
		}
		if (ino == 0)
			break;
		if (!inode.i_links_count)
			continue;
		if (ext2fs_file_acl_block(fs, &inode)) {
			ext2fs_mark_block_bitmap2(meta_block_map,
					ext2fs_file_acl_block(fs, &inode));
			meta_blocks_count++;
		}
		if (!ext2fs_inode_has_valid_blocks2(fs, &inode))
			continue;

		stashed_ino = ino;
		pb.ino = ino;
		pb.is_dir = LINUX_S_ISDIR(inode.i_mode);
		if (LINUX_S_ISDIR(inode.i_mode) ||
		    (LINUX_S_ISLNK(inode.i_mode) &&
		     ext2fs_inode_has_valid_blocks2(fs, &inode)) ||
		    ino == fs->super->s_journal_inum) {
			retval = ext2fs_block_iterate3(fs, ino,
					BLOCK_FLAG_READ_ONLY, block_buf,
					process_dir_block, &pb);
			if (retval) {
				com_err(program_name, retval,
					"while iterating over inode %u",
					ino);
				exit(1);
			}
		} else {
			if ((inode.i_flags & EXT4_EXTENTS_FL) ||
			    inode.i_block[EXT2_IND_BLOCK] ||
			    inode.i_block[EXT2_DIND_BLOCK] ||
			    inode.i_block[EXT2_TIND_BLOCK]) {
				retval = ext2fs_block_iterate3(fs,
				       ino, BLOCK_FLAG_READ_ONLY, block_buf,
				       process_file_block, &pb);
				if (retval) {
					com_err(program_name, retval,
					"while iterating over inode %u", ino);
					exit(1);
				}
			}
		}
	}
	use_inode_shortcuts(fs, 0);

	if (type & E2IMAGE_QCOW2)
		output_qcow2_meta_data_blocks(fs, fd);
	else
		output_meta_data_blocks(fs, fd);

	ext2fs_free_mem(&block_buf);
	ext2fs_close_inode_scan(scan);
	ext2fs_free_block_bitmap(meta_block_map);
	if (type & E2IMAGE_SCRAMBLE_FLAG)
		ext2fs_free_block_bitmap(scramble_block_map);
}

static void install_image(char *device, char *image_fn, int type)
{
	errcode_t retval;
	ext2_filsys fs;
	int open_flag = EXT2_FLAG_IMAGE_FILE;
	int fd = 0;
	io_manager	io_ptr;
	io_channel	io;

	if (type) {
		com_err(program_name, 0, "Raw and qcow2 images cannot"
			"be installed");
		exit(1);
	}

#ifdef CONFIG_TESTIO_DEBUG
	if (getenv("TEST_IO_FLAGS") || getenv("TEST_IO_BLOCK")) {
		io_ptr = test_io_manager;
		test_io_backing_manager = unix_io_manager;
	} else
#endif
		io_ptr = unix_io_manager;

	retval = ext2fs_open (image_fn, open_flag, 0, 0,
			      io_ptr, &fs);
        if (retval) {
		com_err (program_name, retval, _("while trying to open %s"),
			 image_fn);
		exit(1);
	}

	retval = ext2fs_read_bitmaps (fs);
	if (retval) {
		com_err(program_name, retval, "error reading bitmaps");
		exit(1);
	}

	fd = ext2fs_open_file(image_fn, O_RDONLY, 0);
	if (fd < 0) {
		perror(image_fn);
		exit(1);
	}

	retval = io_ptr->open(device, IO_FLAG_RW, &io);
	if (retval) {
		com_err(device, 0, "while opening device file");
		exit(1);
	}

	ext2fs_rewrite_to_io(fs, io);

	if (ext2fs_llseek(fd, fs->image_header->offset_inode, SEEK_SET) < 0) {
		perror("ext2fs_llseek");
		exit(1);
	}

	retval = ext2fs_image_inode_read(fs, fd, 0);
	if (retval) {
		com_err(image_fn, 0, "while restoring the image table");
		exit(1);
	}

	ext2fs_close (fs);
	exit (0);
}

static struct ext2_qcow2_hdr *check_qcow2_image(int *fd, char *name)
{

	*fd = ext2fs_open_file(name, O_RDONLY, 0600);
	if (*fd < 0)
		return NULL;

	return qcow2_read_header(*fd);
}

int main (int argc, char ** argv)
{
	int c;
	errcode_t retval;
	ext2_filsys fs;
	char *image_fn;
	struct ext2_qcow2_hdr *header = NULL;
	int open_flag = EXT2_FLAG_64BITS;
	int img_type = 0;
	int flags = 0;
	int qcow2_fd = 0;
	int fd = 0;
	int ret = 0;

#ifdef ENABLE_NLS
	setlocale(LC_MESSAGES, "");
	setlocale(LC_CTYPE, "");
	bindtextdomain(NLS_CAT_NAME, LOCALEDIR);
	textdomain(NLS_CAT_NAME);
	set_com_err_gettext(gettext);
#endif
	fprintf (stderr, "e2image %s (%s)\n", E2FSPROGS_VERSION,
		 E2FSPROGS_DATE);
	if (argc && *argv)
		program_name = *argv;
	add_error_table(&et_ext2_error_table);
	while ((c = getopt(argc, argv, "rsIQ")) != EOF)
		switch (c) {
		case 'I':
			flags |= E2IMAGE_INSTALL_FLAG;
			break;
		case 'Q':
			if (img_type)
				usage();
			img_type |= E2IMAGE_QCOW2;
			break;
		case 'r':
			if (img_type)
				usage();
			img_type |= E2IMAGE_RAW;
			break;
		case 's':
			flags |= E2IMAGE_SCRAMBLE_FLAG;
			break;
		default:
			usage();
		}
	if (optind != argc - 2 )
		usage();
	device_name = argv[optind];
	image_fn = argv[optind+1];

	if (flags & E2IMAGE_INSTALL_FLAG) {
		install_image(device_name, image_fn, img_type);
		exit (0);
	}

	if (img_type & E2IMAGE_RAW) {
		header = check_qcow2_image(&qcow2_fd, device_name);
		if (header) {
			flags |= E2IMAGE_IS_QCOW2_FLAG;
			goto skip_device;
		}
	}

	retval = ext2fs_open (device_name, open_flag, 0, 0,
			      unix_io_manager, &fs);
        if (retval) {
		com_err (program_name, retval, _("while trying to open %s"),
			 device_name);
		fputs(_("Couldn't find valid filesystem superblock.\n"), stdout);
		exit(1);
	}

skip_device:
	if (strcmp(image_fn, "-") == 0)
		fd = 1;
	else {
		fd = ext2fs_open_file(image_fn, O_CREAT|O_TRUNC|O_WRONLY, 0600);
		if (fd < 0) {
			com_err(program_name, errno,
				_("while trying to open %s"), argv[optind+1]);
			exit(1);
		}
	}

	if ((img_type & E2IMAGE_QCOW2) && (fd == 1)) {
		com_err(program_name, 0, "QCOW2 image can not be written to "
					 "the stdout!\n");
		exit(1);
	}

	if (flags & E2IMAGE_IS_QCOW2_FLAG) {
		ret = qcow2_write_raw_image(qcow2_fd, fd, header);
		if (ret) {
			if (ret == -QCOW_COMPRESSED)
				fprintf(stderr, "Image (%s) is compressed\n",
					image_fn);
			if (ret == -QCOW_ENCRYPTED)
				fprintf(stderr, "Image (%s) is encrypted\n",
					image_fn);
			com_err(program_name, ret,
				_("while trying to convert qcow2 image"
				" (%s) into raw image (%s)"),
				device_name, image_fn);
		}
		goto out;
	}


	if (img_type)
		write_raw_image_file(fs, fd, img_type, flags);
	else
		write_image_file(fs, fd);

	ext2fs_close (fs);
out:
	if (header)
		free(header);
	if (qcow2_fd)
		close(qcow2_fd);
	remove_error_table(&et_ext2_error_table);
	return ret;
}