e2image: Add support for qcow2 format

This commit adds support for exporting filesystem into QCOW2 image
format. Like sparse format this saves space, by writing only necessary
(metadata blocks) into image. Unlike sparse image, QCOW2 image is NOT
sparse, hence does not change its size by copying with not-sparse-aware
tools.

New options '-Q' has been added to tell the e2image to use QCOW2 as an
output image format. QCOW2 supports encryption and compression, however
e2image so far does no support such features, however you can still
scramble filenames with '-s' option.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

2 files changed, 729 insertions, 89 deletions

diff --git a/misc/e2image.8.in b/misc/e2image.8.in
index e18a30b5..90be0d92 100644
--- a/misc/e2image.8.in
+++ b/misc/e2image.8.in
@@ -40,7 +40,8 @@ another program, such as
 (Note that this is currently only supported when
 creating a raw image file using the 
 .B \-r
-option, since the process of creating a normal image file currently
+option, since the process of creating a normal image file, or QCOW2
+image currently
 requires random access to the file, which cannot be done using a
 pipe.  This restriction will hopefully be lifted in a future version of
 .BR e2image .)
@@ -56,13 +57,14 @@ accessible in the case where the filesystem has been badly damaged.
 .PP
 To save disk space, 
 .B e2image
-creates the image file as a sparse file.  
-Hence, if the image file
+creates the image file as a sparse file, or in QCOW2 format.
+Hence, if the sparse image file
 needs to be copied to another location, it should
 either be compressed first or copied using the 
 .B \-\-sparse=always
 option to the GNU version of 
-.BR cp .  
+.BR cp .
+This does not apply to the QCOW2 image, which is not sparse.
 .PP
 The size of an ext2 image file depends primarily on the size of the
 filesystems and how many inodes are in use.  For a typical 10 gigabyte
@@ -129,6 +131,42 @@ the
 option will prevent analysis of problems related to hash-tree indexed
 directories.
 .PP
+.SH QCOW2 IMAGE FILES
+The
+.B \-Q
+option will create a QCOW2 image file instead of a normal, or raw image file.
+A QCOW2 image contains all the information the raw image does, however unlike
+the raw image it is not sparse. The QCOW2 image minimize the amount of disk
+space by storing data in special format with pack data closely together, hence
+avoiding holes while still minimizing size.
+.PP
+In order to send filesystem to the maintainer as a part of bug report to
+e2fsprogs, use following commands (replace hda1 with the appropriate device):
+.PP
+.br
+\	\fBe2image \-Q /dev/hda1 hda1.qcow2\fR
+.br
+\	\fBbzip2 -z hda1.qcow2\fR
+.PP
+This will only send the metadata information, without any data blocks.
+However, the filenames in the directory blocks can still reveal
+information about the contents of the filesystem that the bug reporter
+may wish to keep confidential.  To address this concern, the
+.B \-s
+option can be specified.  This will cause
+.B e2image
+to scramble directory entries and zero out any unused portions
+of the directory blocks before writing the image file.  However, the
+.B \-s
+option will prevent analysis of problems related to hash-tree indexed
+directories.
+.PP
+Note that QCOW2 image created by
+.B e2image
+is regular QCOW2 image and can be processed by tools aware of QCOW2 format
+such as for example
+.BR qemu-img .
+.PP
 .SH AUTHOR
 .B e2image 
 was written by Theodore Ts'o (tytso@mit.edu).
diff --git a/misc/e2image.c b/misc/e2image.c
index 003ac5ad..40ed713b 100644
--- a/misc/e2image.c
+++ b/misc/e2image.c
@@ -33,6 +33,7 @@ extern int optind;
 #include <errno.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <assert.h>
 
 #include "ext2fs/ext2_fs.h"
 #include "ext2fs/ext2fs.h"
@@ -40,51 +41,119 @@ extern int optind;
 #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)
+{
+	perror("seek");
+	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 [-rsI] device image_file\n"),
+	fprintf(stderr, _("Usage: %s [-rsIQ] device image_file\n"),
 		program_name);
 	exit (1);
 }
 
-static void write_header(int fd, struct ext2_image_hdr *hdr, int blocksize)
+static void generic_write(int fd, void *buf, int blocksize, blk64_t block)
 {
-	char *header_buf;
-	int actual;
+	int count, free_buf = 0;
+	errcode_t err;
+	blk64_t offset;
 
-	header_buf = malloc(blocksize);
-	if (!header_buf) {
-		fputs(_("Couldn't allocate header buffer\n"), stderr);
-		exit(1);
+	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);
+		}
 	}
 
-	if (lseek(fd, 0, SEEK_SET) < 0) {
-		perror("lseek while writing header");
+	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);
 	}
-	memset(header_buf, 0, blocksize);
+	if (free_buf)
+		ext2fs_free_mem(&buf);
+}
 
-	if (hdr)
-		memcpy(header_buf, hdr, sizeof(struct ext2_image_hdr));
+static void write_header(int fd, void *hdr, int hdr_size, int wrt_size)
+{
+	char *header_buf;
+	int actual, ret;
 
-	actual = write(fd, header_buf, blocksize);
-	if (actual < 0) {
-		perror("write header");
+	/* 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 (actual != blocksize) {
-		fprintf(stderr, _("short write (only %d bytes) for "
-				  "writing image header"), actual);
+
+	if (ext2fs_llseek(fd, 0, SEEK_SET) < 0) {
+		perror("ext2fs_llseek while writing header");
 		exit(1);
 	}
-	free(header_buf);
+	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)
@@ -93,17 +162,17 @@ static void write_image_file(ext2_filsys fs, int fd)
 	struct stat		st;
 	errcode_t		retval;
 
-	write_header(fd, NULL, fs->blocksize);
+	write_header(fd, NULL, fs->blocksize, fs->blocksize);
 	memset(&hdr, 0, sizeof(struct ext2_image_hdr));
 
-	hdr.offset_super = lseek(fd, 0, SEEK_CUR);
+	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 = lseek(fd, 0, SEEK_CUR);
+	hdr.offset_inode = ext2fs_llseek(fd, 0, SEEK_CUR);
 	retval = ext2fs_image_inode_write(fs, fd,
 				  (fd != 1) ? IMAGER_FLAG_SPARSEWRITE : 0);
 	if (retval) {
@@ -111,14 +180,14 @@ static void write_image_file(ext2_filsys fs, int fd)
 		exit(1);
 	}
 
-	hdr.offset_blockmap = lseek(fd, 0, SEEK_CUR);
+	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 = lseek(fd, 0, SEEK_CUR);
+	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"));
@@ -142,7 +211,7 @@ static void write_image_file(ext2_filsys fs, int fd)
 	memcpy(hdr.fs_uuid, fs->super->s_uuid, sizeof(hdr.fs_uuid));
 
 	hdr.image_time = time(0);
-	write_header(fd, &hdr, fs->blocksize);
+	write_header(fd, &hdr, fs->blocksize, fs->blocksize);
 }
 
 /*
@@ -150,6 +219,7 @@ static void write_image_file(ext2_filsys fs, int fd)
  */
 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;
@@ -226,6 +296,7 @@ static int process_dir_block(ext2_filsys fs EXT2FS_ATTR((unused)),
 	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;
@@ -240,6 +311,7 @@ static int process_file_block(ext2_filsys fs EXT2FS_ATTR((unused)),
 {
 	if (blockcnt < 0) {
 		ext2fs_mark_block_bitmap2(meta_block_map, *block_nr);
+		meta_blocks_count++;
 	}
 	return 0;
 }
@@ -254,6 +326,7 @@ static void mark_table_blocks(ext2_filsys fs)
 	 * Mark primary superblock
 	 */
 	ext2fs_mark_block_bitmap2(meta_block_map, first_block);
+	meta_blocks_count++;
 
 	/*
 	 * Mark the primary superblock descriptors
@@ -262,6 +335,7 @@ static void mark_table_blocks(ext2_filsys fs)
 		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++) {
 		/*
@@ -272,6 +346,7 @@ static void mark_table_blocks(ext2_filsys fs)
 			     j < (unsigned) fs->inode_blocks_per_group;
 			     j++, b++)
 				ext2fs_mark_block_bitmap2(meta_block_map, b);
+			meta_blocks_count += fs->inode_blocks_per_group;
 		}
 
 		/*
@@ -280,6 +355,7 @@ static void mark_table_blocks(ext2_filsys fs)
 		if (ext2fs_block_bitmap_loc(fs, i)) {
 			ext2fs_mark_block_bitmap2(meta_block_map,
 				     ext2fs_block_bitmap_loc(fs, i));
+			meta_blocks_count++;
 		}
 
 		/*
@@ -288,6 +364,7 @@ static void mark_table_blocks(ext2_filsys fs)
 		if (ext2fs_inode_bitmap_loc(fs, i)) {
 			ext2fs_mark_block_bitmap2(meta_block_map,
 				 ext2fs_inode_bitmap_loc(fs, i));
+			meta_blocks_count++;
 		}
 	}
 }
@@ -311,30 +388,14 @@ static int check_zero_block(char *buf, int blocksize)
 static void write_block(int fd, char *buf, int sparse_offset,
 			int blocksize, blk64_t block)
 {
-	int		count;
-	errcode_t	err;
+	ext2_loff_t	ret = 0;
 
-	if (sparse_offset) {
-#ifdef HAVE_LSEEK64
-		if (lseek64(fd, sparse_offset, SEEK_CUR) < 0)
-			perror("lseek");
-#else
-		if (lseek(fd, sparse_offset, SEEK_CUR) < 0)
-			perror("lseek");
-#endif
-	}
-	if (blocksize) {
-		count = write(fd, buf, blocksize);
-		if (count != blocksize) {
-			if (count == -1)
-				err = errno;
-			else
-				err = 0;
-			com_err(program_name, err, "error writing block %llu",
-				block);
-			exit(1);
-		}
-	}
+	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];
@@ -410,17 +471,16 @@ static void output_meta_data_blocks(ext2_filsys fs, int fd)
 	char		*buf, *zero_buf;
 	int		sparse = 0;
 
-	buf = malloc(fs->blocksize);
-	if (!buf) {
-		com_err(program_name, ENOMEM, "while allocating buffer");
+	retval = ext2fs_get_mem(fs->blocksize, &buf);
+	if (retval) {
+		com_err(program_name, retval, "while allocating buffer");
 		exit(1);
 	}
-	zero_buf = malloc(fs->blocksize);
-	if (!zero_buf) {
-		com_err(program_name, ENOMEM, "while allocating buffer");
+	retval = ext2fs_get_memzero(fs->blocksize, &zero_buf);
+	if (retval) {
+		com_err(program_name, retval, "while allocating buffer");
 		exit(1);
 	}
-	memset(zero_buf, 0, fs->blocksize);
 	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)) {
@@ -445,6 +505,7 @@ static void output_meta_data_blocks(ext2_filsys fs, int fd)
 			}
 			sparse += fs->blocksize;
 			if (sparse >= 1024*1024) {
+
 				write_block(fd, 0, sparse, 0, 0);
 				sparse = 0;
 			}
@@ -452,11 +513,530 @@ static void output_meta_data_blocks(ext2_filsys fs, int fd)
 	}
 	if (sparse)
 		write_block(fd, zero_buf, sparse-1, 1, -1);
-	free(zero_buf);
-	free(buf);
+	ext2fs_free_mem(&zero_buf);
+	ext2fs_free_mem(&buf);
 }
 
-static void write_raw_image_file(ext2_filsys fs, int fd, int scramble_flag)
+static void init_l1_table(struct ext2_super_block *sb,
+			  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(sb, image);
+	init_l2_cache(image);
+
+	return 0;
+}
+
+static void free_qcow2_image(struct ext2_qcow2_image *img)
+{
+	unsigned int i;
+
+	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 offset, seek = 0;
+	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, datablk, offset, size, actual, end;
+	char			*buf;
+	int			sparse = 0;
+	struct ext2_qcow2_image	*img;
+	unsigned int		header_size, i;
+	blk64_t			l1_index, l2_offset, l2_index;
+	char			*buffer;
+	__u64			*l2_table;
+
+	/* 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;
@@ -465,6 +1045,7 @@ static void write_raw_image_file(ext2_filsys fs, int fd, int scramble_flag)
 	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) {
@@ -472,7 +1053,7 @@ static void write_raw_image_file(ext2_filsys fs, int fd, int scramble_flag)
 		exit(1);
 	}
 
-	if (scramble_flag) {
+	if (flags & E2IMAGE_SCRAMBLE_FLAG) {
 		retval = ext2fs_allocate_block_bitmap(fs, "scramble block map",
 						      &scramble_block_map);
 		if (retval) {
@@ -490,8 +1071,8 @@ static void write_raw_image_file(ext2_filsys fs, int fd, int scramble_flag)
 		exit(1);
 	}
 
-	block_buf = malloc(fs->blocksize * 3);
-	if (!block_buf) {
+	retval = ext2fs_get_mem(fs->blocksize * 3, &block_buf);
+	if (retval) {
 		com_err(program_name, 0, "Can't allocate block buffer");
 		exit(1);
 	}
@@ -514,6 +1095,7 @@ static void write_raw_image_file(ext2_filsys fs, int fd, int scramble_flag)
 		if (ext2fs_file_acl_block(&inode)) {
 			ext2fs_mark_block_bitmap2(meta_block_map,
 						 ext2fs_file_acl_block(&inode));
+			meta_blocks_count++;
 		}
 		if (!ext2fs_inode_has_valid_blocks(&inode))
 			continue;
@@ -551,21 +1133,31 @@ static void write_raw_image_file(ext2_filsys fs, int fd, int scramble_flag)
 		}
 	}
 	use_inode_shortcuts(fs, 0);
-	output_meta_data_blocks(fs, fd);
-	free(block_buf);
+
+	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 raw_flag)
+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, image_io;
+	io_channel	io;
 
-	if (raw_flag) {
-		com_err(program_name, 0, "Raw images cannot be installed");
+	if (type) {
+		com_err(program_name, 0, "Raw and qcow2 images cannot"
+			"be installed");
 		exit(1);
 	}
 
@@ -607,12 +1199,10 @@ static void install_image(char *device, char *image_fn, int raw_flag)
 		exit(1);
 	}
 
-	image_io = fs->io;
-
 	ext2fs_rewrite_to_io(fs, io);
 
-	if (lseek(fd, fs->image_header->offset_inode, SEEK_SET) < 0) {
-		perror("lseek");
+	if (ext2fs_llseek(fd, fs->image_header->offset_inode, SEEK_SET) < 0) {
+		perror("ext2fs_llseek");
 		exit(1);
 	}
 
@@ -633,9 +1223,8 @@ int main (int argc, char ** argv)
 	ext2_filsys fs;
 	char *image_fn;
 	int open_flag = EXT2_FLAG_64BITS;
-	int raw_flag = 0;
-	int install_flag = 0;
-	int scramble_flag = 0;
+	int img_type = 0;
+	int flags = 0;
 	int fd = 0;
 
 #ifdef ENABLE_NLS
@@ -649,16 +1238,23 @@ int main (int argc, char ** argv)
 	if (argc && *argv)
 		program_name = *argv;
 	add_error_table(&et_ext2_error_table);
-	while ((c = getopt (argc, argv, "rsI")) != EOF)
+	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':
-			raw_flag++;
+			if (img_type)
+				usage();
+			img_type |= E2IMAGE_RAW;
 			break;
 		case 's':
-			scramble_flag++;
-			break;
-		case 'I':
-			install_flag++;
+			flags |= E2IMAGE_SCRAMBLE_FLAG;
 			break;
 		default:
 			usage();
@@ -668,8 +1264,8 @@ int main (int argc, char ** argv)
 	device_name = argv[optind];
 	image_fn = argv[optind+1];
 
-	if (install_flag) {
-		install_image(device_name, image_fn, raw_flag);
+	if (flags & E2IMAGE_INSTALL_FLAG) {
+		install_image(device_name, image_fn, img_type);
 		exit (0);
 	}
 
@@ -697,8 +1293,14 @@ int main (int argc, char ** argv)
 		}
 	}
 
-	if (raw_flag)
-		write_raw_image_file(fs, fd, scramble_flag);
+	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 (img_type)
+		write_raw_image_file(fs, fd, img_type, flags);
 	else
 		write_image_file(fs, fd);