diff --git a/Makefile.common b/Makefile.common
index 7101acb..69961be 100644
--- a/Makefile.common
+++ b/Makefile.common
@@ -634,7 +634,6 @@
 BLOCK_SOURCES += \
     block.c \
     blockdev.c \
-    block/qcow.c \
     block/qcow2.c \
     block/qcow2-refcount.c \
     block/qcow2-snapshot.c \
diff --git a/block/cow.c b/block/cow.c
deleted file mode 100644
index cce970e..0000000
--- a/block/cow.c
+++ /dev/null
@@ -1,324 +0,0 @@
-/*
- * Block driver for the COW format
- *
- * Copyright (c) 2004 Fabrice Bellard
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-#include "qemu-common.h"
-#include "block/block_int.h"
-#include "qemu/module.h"
-
-/**************************************************************/
-/* COW block driver using file system holes */
-
-/* user mode linux compatible COW file */
-#define COW_MAGIC 0x4f4f4f4d  /* MOOO */
-#define COW_VERSION 2
-
-struct cow_header_v2 {
-    uint32_t magic;
-    uint32_t version;
-    char backing_file[1024];
-    int32_t mtime;
-    uint64_t size;
-    uint32_t sectorsize;
-};
-
-typedef struct BDRVCowState {
-    int64_t cow_sectors_offset;
-} BDRVCowState;
-
-static int cow_probe(const uint8_t *buf, int buf_size, const char *filename)
-{
-    const struct cow_header_v2 *cow_header = (const void *)buf;
-
-    if (buf_size >= sizeof(struct cow_header_v2) &&
-        be32_to_cpu(cow_header->magic) == COW_MAGIC &&
-        be32_to_cpu(cow_header->version) == COW_VERSION)
-        return 100;
-    else
-        return 0;
-}
-
-static int cow_open(BlockDriverState *bs, int flags)
-{
-    BDRVCowState *s = bs->opaque;
-    struct cow_header_v2 cow_header;
-    int bitmap_size;
-    int64_t size;
-
-    /* see if it is a cow image */
-    if (bdrv_pread(bs->file, 0, &cow_header, sizeof(cow_header)) !=
-            sizeof(cow_header)) {
-        goto fail;
-    }
-
-    if (be32_to_cpu(cow_header.magic) != COW_MAGIC ||
-        be32_to_cpu(cow_header.version) != COW_VERSION) {
-        goto fail;
-    }
-
-    /* cow image found */
-    size = be64_to_cpu(cow_header.size);
-    bs->total_sectors = size / 512;
-
-    pstrcpy(bs->backing_file, sizeof(bs->backing_file),
-            cow_header.backing_file);
-
-    bitmap_size = ((bs->total_sectors + 7) >> 3) + sizeof(cow_header);
-    s->cow_sectors_offset = (bitmap_size + 511) & ~511;
-    return 0;
- fail:
-    return -1;
-}
-
-/*
- * XXX(hch): right now these functions are extremly ineffcient.
- * We should just read the whole bitmap we'll need in one go instead.
- */
-static inline int cow_set_bit(BlockDriverState *bs, int64_t bitnum)
-{
-    uint64_t offset = sizeof(struct cow_header_v2) + bitnum / 8;
-    uint8_t bitmap;
-    int ret;
-
-    ret = bdrv_pread(bs->file, offset, &bitmap, sizeof(bitmap));
-    if (ret < 0) {
-       return ret;
-    }
-
-    bitmap |= (1 << (bitnum % 8));
-
-    ret = bdrv_pwrite_sync(bs->file, offset, &bitmap, sizeof(bitmap));
-    if (ret < 0) {
-       return ret;
-    }
-    return 0;
-}
-
-static inline int is_bit_set(BlockDriverState *bs, int64_t bitnum)
-{
-    uint64_t offset = sizeof(struct cow_header_v2) + bitnum / 8;
-    uint8_t bitmap;
-    int ret;
-
-    ret = bdrv_pread(bs->file, offset, &bitmap, sizeof(bitmap));
-    if (ret < 0) {
-       return ret;
-    }
-
-    return !!(bitmap & (1 << (bitnum % 8)));
-}
-
-/* Return true if first block has been changed (ie. current version is
- * in COW file).  Set the number of continuous blocks for which that
- * is true. */
-static int cow_is_allocated(BlockDriverState *bs, int64_t sector_num,
-        int nb_sectors, int *num_same)
-{
-    int changed;
-
-    if (nb_sectors == 0) {
-	*num_same = nb_sectors;
-	return 0;
-    }
-
-    changed = is_bit_set(bs, sector_num);
-    if (changed < 0) {
-        return 0; /* XXX: how to return I/O errors? */
-    }
-
-    for (*num_same = 1; *num_same < nb_sectors; (*num_same)++) {
-	if (is_bit_set(bs, sector_num + *num_same) != changed)
-	    break;
-    }
-
-    return changed;
-}
-
-static int cow_update_bitmap(BlockDriverState *bs, int64_t sector_num,
-        int nb_sectors)
-{
-    int error = 0;
-    int i;
-
-    for (i = 0; i < nb_sectors; i++) {
-        error = cow_set_bit(bs, sector_num + i);
-        if (error) {
-            break;
-        }
-    }
-
-    return error;
-}
-
-static int cow_read(BlockDriverState *bs, int64_t sector_num,
-                    uint8_t *buf, int nb_sectors)
-{
-    BDRVCowState *s = bs->opaque;
-    int ret, n;
-
-    while (nb_sectors > 0) {
-        if (cow_is_allocated(bs, sector_num, nb_sectors, &n)) {
-            ret = bdrv_pread(bs->file,
-                        s->cow_sectors_offset + sector_num * 512,
-                        buf, n * 512);
-            if (ret != n * 512)
-                return -1;
-        } else {
-            if (bs->backing_hd) {
-                /* read from the base image */
-                ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
-                if (ret < 0)
-                    return -1;
-            } else {
-            memset(buf, 0, n * 512);
-        }
-        }
-        nb_sectors -= n;
-        sector_num += n;
-        buf += n * 512;
-    }
-    return 0;
-}
-
-static int cow_write(BlockDriverState *bs, int64_t sector_num,
-                     const uint8_t *buf, int nb_sectors)
-{
-    BDRVCowState *s = bs->opaque;
-    int ret;
-
-    ret = bdrv_pwrite(bs->file, s->cow_sectors_offset + sector_num * 512,
-                      buf, nb_sectors * 512);
-    if (ret != nb_sectors * 512)
-        return -1;
-
-    return cow_update_bitmap(bs, sector_num, nb_sectors);
-}
-
-static void cow_close(BlockDriverState *bs)
-{
-}
-
-static int cow_create(const char *filename, QEMUOptionParameter *options)
-{
-    int fd, cow_fd;
-    struct cow_header_v2 cow_header;
-    struct stat st;
-    int64_t image_sectors = 0;
-    const char *image_filename = NULL;
-    int ret;
-
-    /* Read out options */
-    while (options && options->name) {
-        if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
-            image_sectors = options->value.n / 512;
-        } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
-            image_filename = options->value.s;
-        }
-        options++;
-    }
-
-    cow_fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
-              0644);
-    if (cow_fd < 0)
-        return -errno;
-    memset(&cow_header, 0, sizeof(cow_header));
-    cow_header.magic = cpu_to_be32(COW_MAGIC);
-    cow_header.version = cpu_to_be32(COW_VERSION);
-    if (image_filename) {
-        /* Note: if no file, we put a dummy mtime */
-        cow_header.mtime = cpu_to_be32(0);
-
-        fd = open(image_filename, O_RDONLY | O_BINARY);
-        if (fd < 0) {
-            close(cow_fd);
-            goto mtime_fail;
-        }
-        if (fstat(fd, &st) != 0) {
-            close(fd);
-            goto mtime_fail;
-        }
-        close(fd);
-        cow_header.mtime = cpu_to_be32(st.st_mtime);
-    mtime_fail:
-        pstrcpy(cow_header.backing_file, sizeof(cow_header.backing_file),
-                image_filename);
-    }
-    cow_header.sectorsize = cpu_to_be32(512);
-    cow_header.size = cpu_to_be64(image_sectors * 512);
-    ret = qemu_write_full(cow_fd, &cow_header, sizeof(cow_header));
-    if (ret != sizeof(cow_header)) {
-        ret = -errno;
-        goto exit;
-    }
-
-    /* resize to include at least all the bitmap */
-    ret = ftruncate(cow_fd, sizeof(cow_header) + ((image_sectors + 7) >> 3));
-    if (ret) {
-        ret = -errno;
-        goto exit;
-    }
-
-exit:
-    close(cow_fd);
-    return ret;
-}
-
-static void cow_flush(BlockDriverState *bs)
-{
-    bdrv_flush(bs->file);
-}
-
-static QEMUOptionParameter cow_create_options[] = {
-    {
-        .name = BLOCK_OPT_SIZE,
-        .type = OPT_SIZE,
-        .help = "Virtual disk size"
-    },
-    {
-        .name = BLOCK_OPT_BACKING_FILE,
-        .type = OPT_STRING,
-        .help = "File name of a base image"
-    },
-    { NULL }
-};
-
-static BlockDriver bdrv_cow = {
-    .format_name	= "cow",
-    .instance_size	= sizeof(BDRVCowState),
-    .bdrv_probe		= cow_probe,
-    .bdrv_open		= cow_open,
-    .bdrv_read		= cow_read,
-    .bdrv_write		= cow_write,
-    .bdrv_close		= cow_close,
-    .bdrv_create	= cow_create,
-    .bdrv_flush		= cow_flush,
-    .bdrv_is_allocated	= cow_is_allocated,
-
-    .create_options = cow_create_options,
-};
-
-static void bdrv_cow_init(void)
-{
-    bdrv_register(&bdrv_cow);
-}
-
-block_init(bdrv_cow_init);
diff --git a/block/qcow.c b/block/qcow.c
deleted file mode 100644
index 7b22d32..0000000
--- a/block/qcow.c
+++ /dev/null
@@ -1,977 +0,0 @@
-/*
- * Block driver for the QCOW format
- *
- * Copyright (c) 2004-2006 Fabrice Bellard
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-#include "qemu-common.h"
-#include "block/block_int.h"
-#include "qemu/iov.h"
-#include "qemu/module.h"
-#include <zlib.h>
-#include "qemu/aes.h"
-
-/**************************************************************/
-/* QEMU COW block driver with compression and encryption support */
-
-#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
-#define QCOW_VERSION 1
-
-#define QCOW_CRYPT_NONE 0
-#define QCOW_CRYPT_AES  1
-
-#define QCOW_OFLAG_COMPRESSED (1LL << 63)
-
-typedef struct QCowHeader {
-    uint32_t magic;
-    uint32_t version;
-    uint64_t backing_file_offset;
-    uint32_t backing_file_size;
-    uint32_t mtime;
-    uint64_t size; /* in bytes */
-    uint8_t cluster_bits;
-    uint8_t l2_bits;
-    uint32_t crypt_method;
-    uint64_t l1_table_offset;
-} QCowHeader;
-
-#define L2_CACHE_SIZE 16
-
-typedef struct BDRVQcowState {
-    BlockDriverState *hd;
-    int cluster_bits;
-    int cluster_size;
-    int cluster_sectors;
-    int l2_bits;
-    int l2_size;
-    int l1_size;
-    uint64_t cluster_offset_mask;
-    uint64_t l1_table_offset;
-    uint64_t *l1_table;
-    uint64_t *l2_cache;
-    uint64_t l2_cache_offsets[L2_CACHE_SIZE];
-    uint32_t l2_cache_counts[L2_CACHE_SIZE];
-    uint8_t *cluster_cache;
-    uint8_t *cluster_data;
-    uint64_t cluster_cache_offset;
-    uint32_t crypt_method; /* current crypt method, 0 if no key yet */
-    uint32_t crypt_method_header;
-    AES_KEY aes_encrypt_key;
-    AES_KEY aes_decrypt_key;
-} BDRVQcowState;
-
-static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
-
-static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
-{
-    const QCowHeader *cow_header = (const void *)buf;
-
-    if (buf_size >= sizeof(QCowHeader) &&
-        be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
-        be32_to_cpu(cow_header->version) == QCOW_VERSION)
-        return 100;
-    else
-        return 0;
-}
-
-static int qcow_open(BlockDriverState *bs, int flags)
-{
-    BDRVQcowState *s = bs->opaque;
-    int len, i, shift;
-    QCowHeader header;
-
-    if (bdrv_pread(bs->file, 0, &header, sizeof(header)) != sizeof(header))
-        goto fail;
-    be32_to_cpus(&header.magic);
-    be32_to_cpus(&header.version);
-    be64_to_cpus(&header.backing_file_offset);
-    be32_to_cpus(&header.backing_file_size);
-    be32_to_cpus(&header.mtime);
-    be64_to_cpus(&header.size);
-    be32_to_cpus(&header.crypt_method);
-    be64_to_cpus(&header.l1_table_offset);
-
-    if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
-        goto fail;
-    if (header.size <= 1 || header.cluster_bits < 9)
-        goto fail;
-    if (header.crypt_method > QCOW_CRYPT_AES)
-        goto fail;
-    s->crypt_method_header = header.crypt_method;
-    if (s->crypt_method_header)
-        bs->encrypted = 1;
-    s->cluster_bits = header.cluster_bits;
-    s->cluster_size = 1 << s->cluster_bits;
-    s->cluster_sectors = 1 << (s->cluster_bits - 9);
-    s->l2_bits = header.l2_bits;
-    s->l2_size = 1 << s->l2_bits;
-    bs->total_sectors = header.size / 512;
-    s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
-
-    /* read the level 1 table */
-    shift = s->cluster_bits + s->l2_bits;
-    s->l1_size = (header.size + (1LL << shift) - 1) >> shift;
-
-    s->l1_table_offset = header.l1_table_offset;
-    s->l1_table = g_malloc(s->l1_size * sizeof(uint64_t));
-    if (!s->l1_table)
-        goto fail;
-    if (bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
-        s->l1_size * sizeof(uint64_t))
-        goto fail;
-    for(i = 0;i < s->l1_size; i++) {
-        be64_to_cpus(&s->l1_table[i]);
-    }
-    /* alloc L2 cache */
-    s->l2_cache = g_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
-    if (!s->l2_cache)
-        goto fail;
-    s->cluster_cache = g_malloc(s->cluster_size);
-    if (!s->cluster_cache)
-        goto fail;
-    s->cluster_data = g_malloc(s->cluster_size);
-    if (!s->cluster_data)
-        goto fail;
-    s->cluster_cache_offset = -1;
-
-    /* read the backing file name */
-    if (header.backing_file_offset != 0) {
-        len = header.backing_file_size;
-        if (len > 1023)
-            len = 1023;
-        if (bdrv_pread(bs->file, header.backing_file_offset, bs->backing_file, len) != len)
-            goto fail;
-        bs->backing_file[len] = '\0';
-    }
-    return 0;
-
- fail:
-    g_free(s->l1_table);
-    g_free(s->l2_cache);
-    g_free(s->cluster_cache);
-    g_free(s->cluster_data);
-    return -1;
-}
-
-static int qcow_set_key(BlockDriverState *bs, const char *key)
-{
-    BDRVQcowState *s = bs->opaque;
-    uint8_t keybuf[16];
-    int len, i;
-
-    memset(keybuf, 0, 16);
-    len = strlen(key);
-    if (len > 16)
-        len = 16;
-    /* XXX: we could compress the chars to 7 bits to increase
-       entropy */
-    for(i = 0;i < len;i++) {
-        keybuf[i] = key[i];
-    }
-    s->crypt_method = s->crypt_method_header;
-
-    if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
-        return -1;
-    if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
-        return -1;
-#if 0
-    /* test */
-    {
-        uint8_t in[16];
-        uint8_t out[16];
-        uint8_t tmp[16];
-        for(i=0;i<16;i++)
-            in[i] = i;
-        AES_encrypt(in, tmp, &s->aes_encrypt_key);
-        AES_decrypt(tmp, out, &s->aes_decrypt_key);
-        for(i = 0; i < 16; i++)
-            printf(" %02x", tmp[i]);
-        printf("\n");
-        for(i = 0; i < 16; i++)
-            printf(" %02x", out[i]);
-        printf("\n");
-    }
-#endif
-    return 0;
-}
-
-/* The crypt function is compatible with the linux cryptoloop
-   algorithm for < 4 GB images. NOTE: out_buf == in_buf is
-   supported */
-static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
-                            uint8_t *out_buf, const uint8_t *in_buf,
-                            int nb_sectors, int enc,
-                            const AES_KEY *key)
-{
-    union {
-        uint64_t ll[2];
-        uint8_t b[16];
-    } ivec;
-    int i;
-
-    for(i = 0; i < nb_sectors; i++) {
-        ivec.ll[0] = cpu_to_le64(sector_num);
-        ivec.ll[1] = 0;
-        AES_cbc_encrypt(in_buf, out_buf, 512, key,
-                        ivec.b, enc);
-        sector_num++;
-        in_buf += 512;
-        out_buf += 512;
-    }
-}
-
-/* 'allocate' is:
- *
- * 0 to not allocate.
- *
- * 1 to allocate a normal cluster (for sector indexes 'n_start' to
- * 'n_end')
- *
- * 2 to allocate a compressed cluster of size
- * 'compressed_size'. 'compressed_size' must be > 0 and <
- * cluster_size
- *
- * return 0 if not allocated.
- */
-static uint64_t get_cluster_offset(BlockDriverState *bs,
-                                   uint64_t offset, int allocate,
-                                   int compressed_size,
-                                   int n_start, int n_end)
-{
-    BDRVQcowState *s = bs->opaque;
-    int min_index, i, j, l1_index, l2_index;
-    uint64_t l2_offset, *l2_table, cluster_offset, tmp;
-    uint32_t min_count;
-    int new_l2_table;
-
-    l1_index = offset >> (s->l2_bits + s->cluster_bits);
-    l2_offset = s->l1_table[l1_index];
-    new_l2_table = 0;
-    if (!l2_offset) {
-        if (!allocate)
-            return 0;
-        /* allocate a new l2 entry */
-        l2_offset = bdrv_getlength(bs->file);
-        /* round to cluster size */
-        l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
-        /* update the L1 entry */
-        s->l1_table[l1_index] = l2_offset;
-        tmp = cpu_to_be64(l2_offset);
-        if (bdrv_pwrite_sync(bs->file,
-                s->l1_table_offset + l1_index * sizeof(tmp),
-                &tmp, sizeof(tmp)) < 0)
-            return 0;
-        new_l2_table = 1;
-    }
-    for(i = 0; i < L2_CACHE_SIZE; i++) {
-        if (l2_offset == s->l2_cache_offsets[i]) {
-            /* increment the hit count */
-            if (++s->l2_cache_counts[i] == 0xffffffff) {
-                for(j = 0; j < L2_CACHE_SIZE; j++) {
-                    s->l2_cache_counts[j] >>= 1;
-                }
-            }
-            l2_table = s->l2_cache + (i << s->l2_bits);
-            goto found;
-        }
-    }
-    /* not found: load a new entry in the least used one */
-    min_index = 0;
-    min_count = 0xffffffff;
-    for(i = 0; i < L2_CACHE_SIZE; i++) {
-        if (s->l2_cache_counts[i] < min_count) {
-            min_count = s->l2_cache_counts[i];
-            min_index = i;
-        }
-    }
-    l2_table = s->l2_cache + (min_index << s->l2_bits);
-    if (new_l2_table) {
-        memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
-        if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
-                s->l2_size * sizeof(uint64_t)) < 0)
-            return 0;
-    } else {
-        if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
-            s->l2_size * sizeof(uint64_t))
-            return 0;
-    }
-    s->l2_cache_offsets[min_index] = l2_offset;
-    s->l2_cache_counts[min_index] = 1;
- found:
-    l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
-    cluster_offset = be64_to_cpu(l2_table[l2_index]);
-    if (!cluster_offset ||
-        ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
-        if (!allocate)
-            return 0;
-        /* allocate a new cluster */
-        if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
-            (n_end - n_start) < s->cluster_sectors) {
-            /* if the cluster is already compressed, we must
-               decompress it in the case it is not completely
-               overwritten */
-            if (decompress_cluster(bs, cluster_offset) < 0)
-                return 0;
-            cluster_offset = bdrv_getlength(bs->file);
-            cluster_offset = (cluster_offset + s->cluster_size - 1) &
-                ~(s->cluster_size - 1);
-            /* write the cluster content */
-            if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) !=
-                s->cluster_size)
-                return -1;
-        } else {
-            cluster_offset = bdrv_getlength(bs->file);
-            if (allocate == 1) {
-                /* round to cluster size */
-                cluster_offset = (cluster_offset + s->cluster_size - 1) &
-                    ~(s->cluster_size - 1);
-                bdrv_truncate(bs->file, cluster_offset + s->cluster_size);
-                /* if encrypted, we must initialize the cluster
-                   content which won't be written */
-                if (s->crypt_method &&
-                    (n_end - n_start) < s->cluster_sectors) {
-                    uint64_t start_sect;
-                    start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
-                    memset(s->cluster_data + 512, 0x00, 512);
-                    for(i = 0; i < s->cluster_sectors; i++) {
-                        if (i < n_start || i >= n_end) {
-                            encrypt_sectors(s, start_sect + i,
-                                            s->cluster_data,
-                                            s->cluster_data + 512, 1, 1,
-                                            &s->aes_encrypt_key);
-                            if (bdrv_pwrite(bs->file, cluster_offset + i * 512,
-                                            s->cluster_data, 512) != 512)
-                                return -1;
-                        }
-                    }
-                }
-            } else if (allocate == 2) {
-                cluster_offset |= QCOW_OFLAG_COMPRESSED |
-                    (uint64_t)compressed_size << (63 - s->cluster_bits);
-            }
-        }
-        /* update L2 table */
-        tmp = cpu_to_be64(cluster_offset);
-        l2_table[l2_index] = tmp;
-        if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
-                &tmp, sizeof(tmp)) < 0)
-            return 0;
-    }
-    return cluster_offset;
-}
-
-static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
-                             int nb_sectors, int *pnum)
-{
-    BDRVQcowState *s = bs->opaque;
-    int index_in_cluster, n;
-    uint64_t cluster_offset;
-
-    cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
-    index_in_cluster = sector_num & (s->cluster_sectors - 1);
-    n = s->cluster_sectors - index_in_cluster;
-    if (n > nb_sectors)
-        n = nb_sectors;
-    *pnum = n;
-    return (cluster_offset != 0);
-}
-
-static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
-                             const uint8_t *buf, int buf_size)
-{
-    z_stream strm1, *strm = &strm1;
-    int ret, out_len;
-
-    memset(strm, 0, sizeof(*strm));
-
-    strm->next_in = (uint8_t *)buf;
-    strm->avail_in = buf_size;
-    strm->next_out = out_buf;
-    strm->avail_out = out_buf_size;
-
-    ret = inflateInit2(strm, -12);
-    if (ret != Z_OK)
-        return -1;
-    ret = inflate(strm, Z_FINISH);
-    out_len = strm->next_out - out_buf;
-    if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
-        out_len != out_buf_size) {
-        inflateEnd(strm);
-        return -1;
-    }
-    inflateEnd(strm);
-    return 0;
-}
-
-static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
-{
-    BDRVQcowState *s = bs->opaque;
-    int ret, csize;
-    uint64_t coffset;
-
-    coffset = cluster_offset & s->cluster_offset_mask;
-    if (s->cluster_cache_offset != coffset) {
-        csize = cluster_offset >> (63 - s->cluster_bits);
-        csize &= (s->cluster_size - 1);
-        ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
-        if (ret != csize)
-            return -1;
-        if (decompress_buffer(s->cluster_cache, s->cluster_size,
-                              s->cluster_data, csize) < 0) {
-            return -1;
-        }
-        s->cluster_cache_offset = coffset;
-    }
-    return 0;
-}
-
-#if 0
-
-static int qcow_read(BlockDriverState *bs, int64_t sector_num,
-                     uint8_t *buf, int nb_sectors)
-{
-    BDRVQcowState *s = bs->opaque;
-    int ret, index_in_cluster, n;
-    uint64_t cluster_offset;
-
-    while (nb_sectors > 0) {
-        cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
-        index_in_cluster = sector_num & (s->cluster_sectors - 1);
-        n = s->cluster_sectors - index_in_cluster;
-        if (n > nb_sectors)
-            n = nb_sectors;
-        if (!cluster_offset) {
-            if (bs->backing_hd) {
-                /* read from the base image */
-                ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
-                if (ret < 0)
-                    return -1;
-            } else {
-                memset(buf, 0, 512 * n);
-            }
-        } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
-            if (decompress_cluster(bs, cluster_offset) < 0)
-                return -1;
-            memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
-        } else {
-            ret = bdrv_pread(bs->file, cluster_offset + index_in_cluster * 512, buf, n * 512);
-            if (ret != n * 512)
-                return -1;
-            if (s->crypt_method) {
-                encrypt_sectors(s, sector_num, buf, buf, n, 0,
-                                &s->aes_decrypt_key);
-            }
-        }
-        nb_sectors -= n;
-        sector_num += n;
-        buf += n * 512;
-    }
-    return 0;
-}
-#endif
-
-typedef struct QCowAIOCB {
-    BlockDriverAIOCB common;
-    int64_t sector_num;
-    QEMUIOVector *qiov;
-    uint8_t *buf;
-    void *orig_buf;
-    int nb_sectors;
-    int n;
-    uint64_t cluster_offset;
-    uint8_t *cluster_data;
-    struct iovec hd_iov;
-    QEMUIOVector hd_qiov;
-    BlockDriverAIOCB *hd_aiocb;
-} QCowAIOCB;
-
-static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
-{
-    QCowAIOCB *acb = container_of(blockacb, QCowAIOCB, common);
-    if (acb->hd_aiocb)
-        bdrv_aio_cancel(acb->hd_aiocb);
-    qemu_aio_release(acb);
-}
-
-static AIOPool qcow_aio_pool = {
-    .aiocb_size         = sizeof(QCowAIOCB),
-    .cancel             = qcow_aio_cancel,
-};
-
-static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
-        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
-        BlockDriverCompletionFunc *cb, void *opaque, int is_write)
-{
-    QCowAIOCB *acb;
-
-    acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque);
-    if (!acb)
-        return NULL;
-    acb->hd_aiocb = NULL;
-    acb->sector_num = sector_num;
-    acb->qiov = qiov;
-    if (qiov->niov > 1) {
-        acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size);
-        if (is_write)
-            qemu_iovec_to_buf(qiov, 0, acb->buf, qiov->size);
-    } else {
-        acb->buf = (uint8_t *)qiov->iov->iov_base;
-    }
-    acb->nb_sectors = nb_sectors;
-    acb->n = 0;
-    acb->cluster_offset = 0;
-    return acb;
-}
-
-static void qcow_aio_read_cb(void *opaque, int ret)
-{
-    QCowAIOCB *acb = opaque;
-    BlockDriverState *bs = acb->common.bs;
-    BDRVQcowState *s = bs->opaque;
-    int index_in_cluster;
-
-    acb->hd_aiocb = NULL;
-    if (ret < 0)
-        goto done;
-
- redo:
-    /* post process the read buffer */
-    if (!acb->cluster_offset) {
-        /* nothing to do */
-    } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
-        /* nothing to do */
-    } else {
-        if (s->crypt_method) {
-            encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf,
-                            acb->n, 0,
-                            &s->aes_decrypt_key);
-        }
-    }
-
-    acb->nb_sectors -= acb->n;
-    acb->sector_num += acb->n;
-    acb->buf += acb->n * 512;
-
-    if (acb->nb_sectors == 0) {
-        /* request completed */
-        ret = 0;
-        goto done;
-    }
-
-    /* prepare next AIO request */
-    acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9,
-                                             0, 0, 0, 0);
-    index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
-    acb->n = s->cluster_sectors - index_in_cluster;
-    if (acb->n > acb->nb_sectors)
-        acb->n = acb->nb_sectors;
-
-    if (!acb->cluster_offset) {
-        if (bs->backing_hd) {
-            /* read from the base image */
-            acb->hd_iov.iov_base = (void *)acb->buf;
-            acb->hd_iov.iov_len = acb->n * 512;
-            qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
-            acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num,
-                &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
-            if (acb->hd_aiocb == NULL)
-                goto done;
-        } else {
-            /* Note: in this case, no need to wait */
-            memset(acb->buf, 0, 512 * acb->n);
-            goto redo;
-        }
-    } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
-        /* add AIO support for compressed blocks ? */
-        if (decompress_cluster(bs, acb->cluster_offset) < 0)
-            goto done;
-        memcpy(acb->buf,
-               s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
-        goto redo;
-    } else {
-        if ((acb->cluster_offset & 511) != 0) {
-            ret = -EIO;
-            goto done;
-        }
-        acb->hd_iov.iov_base = (void *)acb->buf;
-        acb->hd_iov.iov_len = acb->n * 512;
-        qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
-        acb->hd_aiocb = bdrv_aio_readv(bs->file,
-                            (acb->cluster_offset >> 9) + index_in_cluster,
-                            &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
-        if (acb->hd_aiocb == NULL)
-            goto done;
-    }
-
-    return;
-
-done:
-    if (acb->qiov->niov > 1) {
-        qemu_iovec_from_buf(acb->qiov, 0, acb->orig_buf, acb->qiov->size);
-        qemu_vfree(acb->orig_buf);
-    }
-    acb->common.cb(acb->common.opaque, ret);
-    qemu_aio_release(acb);
-}
-
-static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs,
-        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
-        BlockDriverCompletionFunc *cb, void *opaque)
-{
-    QCowAIOCB *acb;
-
-    acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
-    if (!acb)
-        return NULL;
-
-    qcow_aio_read_cb(acb, 0);
-    return &acb->common;
-}
-
-static void qcow_aio_write_cb(void *opaque, int ret)
-{
-    QCowAIOCB *acb = opaque;
-    BlockDriverState *bs = acb->common.bs;
-    BDRVQcowState *s = bs->opaque;
-    int index_in_cluster;
-    uint64_t cluster_offset;
-    const uint8_t *src_buf;
-
-    acb->hd_aiocb = NULL;
-
-    if (ret < 0)
-        goto done;
-
-    acb->nb_sectors -= acb->n;
-    acb->sector_num += acb->n;
-    acb->buf += acb->n * 512;
-
-    if (acb->nb_sectors == 0) {
-        /* request completed */
-        ret = 0;
-        goto done;
-    }
-
-    index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
-    acb->n = s->cluster_sectors - index_in_cluster;
-    if (acb->n > acb->nb_sectors)
-        acb->n = acb->nb_sectors;
-    cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 1, 0,
-                                        index_in_cluster,
-                                        index_in_cluster + acb->n);
-    if (!cluster_offset || (cluster_offset & 511) != 0) {
-        ret = -EIO;
-        goto done;
-    }
-    if (s->crypt_method) {
-        if (!acb->cluster_data) {
-            acb->cluster_data = g_malloc0(s->cluster_size);
-            if (!acb->cluster_data) {
-                ret = -ENOMEM;
-                goto done;
-            }
-        }
-        encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
-                        acb->n, 1, &s->aes_encrypt_key);
-        src_buf = acb->cluster_data;
-    } else {
-        src_buf = acb->buf;
-    }
-
-    acb->hd_iov.iov_base = (void *)src_buf;
-    acb->hd_iov.iov_len = acb->n * 512;
-    qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
-    acb->hd_aiocb = bdrv_aio_writev(bs->file,
-                                    (cluster_offset >> 9) + index_in_cluster,
-                                    &acb->hd_qiov, acb->n,
-                                    qcow_aio_write_cb, acb);
-    if (acb->hd_aiocb == NULL)
-        goto done;
-    return;
-
-done:
-    if (acb->qiov->niov > 1)
-        qemu_vfree(acb->orig_buf);
-    acb->common.cb(acb->common.opaque, ret);
-    qemu_aio_release(acb);
-}
-
-static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
-        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
-        BlockDriverCompletionFunc *cb, void *opaque)
-{
-    BDRVQcowState *s = bs->opaque;
-    QCowAIOCB *acb;
-
-    s->cluster_cache_offset = -1; /* disable compressed cache */
-
-    acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
-    if (!acb)
-        return NULL;
-
-
-    qcow_aio_write_cb(acb, 0);
-    return &acb->common;
-}
-
-static void qcow_close(BlockDriverState *bs)
-{
-    BDRVQcowState *s = bs->opaque;
-    g_free(s->l1_table);
-    g_free(s->l2_cache);
-    g_free(s->cluster_cache);
-    g_free(s->cluster_data);
-}
-
-static int qcow_create(const char *filename, QEMUOptionParameter *options)
-{
-    int fd, header_size, backing_filename_len, l1_size, i, shift;
-    QCowHeader header;
-    uint64_t tmp;
-    int64_t total_size = 0;
-    const char *backing_file = NULL;
-    int flags = 0;
-    int ret;
-
-    /* Read out options */
-    while (options && options->name) {
-        if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
-            total_size = options->value.n / 512;
-        } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
-            backing_file = options->value.s;
-        } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) {
-            flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
-        }
-        options++;
-    }
-
-    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
-    if (fd < 0)
-        return -errno;
-    memset(&header, 0, sizeof(header));
-    header.magic = cpu_to_be32(QCOW_MAGIC);
-    header.version = cpu_to_be32(QCOW_VERSION);
-    header.size = cpu_to_be64(total_size * 512);
-    header_size = sizeof(header);
-    backing_filename_len = 0;
-    if (backing_file) {
-        if (strcmp(backing_file, "fat:")) {
-            header.backing_file_offset = cpu_to_be64(header_size);
-            backing_filename_len = strlen(backing_file);
-            header.backing_file_size = cpu_to_be32(backing_filename_len);
-            header_size += backing_filename_len;
-        } else {
-            /* special backing file for vvfat */
-            backing_file = NULL;
-        }
-        header.cluster_bits = 9; /* 512 byte cluster to avoid copying
-                                    unmodifyed sectors */
-        header.l2_bits = 12; /* 32 KB L2 tables */
-    } else {
-        header.cluster_bits = 12; /* 4 KB clusters */
-        header.l2_bits = 9; /* 4 KB L2 tables */
-    }
-    header_size = (header_size + 7) & ~7;
-    shift = header.cluster_bits + header.l2_bits;
-    l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift;
-
-    header.l1_table_offset = cpu_to_be64(header_size);
-    if (flags & BLOCK_FLAG_ENCRYPT) {
-        header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
-    } else {
-        header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
-    }
-
-    /* write all the data */
-    ret = qemu_write_full(fd, &header, sizeof(header));
-    if (ret != sizeof(header)) {
-        ret = -errno;
-        goto exit;
-    }
-
-    if (backing_file) {
-        ret = qemu_write_full(fd, backing_file, backing_filename_len);
-        if (ret != backing_filename_len) {
-            ret = -errno;
-            goto exit;
-        }
-
-    }
-    lseek(fd, header_size, SEEK_SET);
-    tmp = 0;
-    for(i = 0;i < l1_size; i++) {
-        ret = qemu_write_full(fd, &tmp, sizeof(tmp));
-        if (ret != sizeof(tmp)) {
-            ret = -errno;
-            goto exit;
-        }
-    }
-
-    ret = 0;
-exit:
-    close(fd);
-    return ret;
-}
-
-static int qcow_make_empty(BlockDriverState *bs)
-{
-    BDRVQcowState *s = bs->opaque;
-    uint32_t l1_length = s->l1_size * sizeof(uint64_t);
-    int ret;
-
-    memset(s->l1_table, 0, l1_length);
-    if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table,
-            l1_length) < 0)
-        return -1;
-    ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length);
-    if (ret < 0)
-        return ret;
-
-    memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
-    memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
-    memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
-
-    return 0;
-}
-
-/* XXX: put compressed sectors first, then all the cluster aligned
-   tables to avoid losing bytes in alignment */
-static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
-                                 const uint8_t *buf, int nb_sectors)
-{
-    BDRVQcowState *s = bs->opaque;
-    z_stream strm;
-    int ret, out_len;
-    uint8_t *out_buf;
-    uint64_t cluster_offset;
-
-    if (nb_sectors != s->cluster_sectors)
-        return -EINVAL;
-
-    out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
-    if (!out_buf)
-        return -1;
-
-    /* best compression, small window, no zlib header */
-    memset(&strm, 0, sizeof(strm));
-    ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
-                       Z_DEFLATED, -12,
-                       9, Z_DEFAULT_STRATEGY);
-    if (ret != 0) {
-        g_free(out_buf);
-        return -1;
-    }
-
-    strm.avail_in = s->cluster_size;
-    strm.next_in = (uint8_t *)buf;
-    strm.avail_out = s->cluster_size;
-    strm.next_out = out_buf;
-
-    ret = deflate(&strm, Z_FINISH);
-    if (ret != Z_STREAM_END && ret != Z_OK) {
-        g_free(out_buf);
-        deflateEnd(&strm);
-        return -1;
-    }
-    out_len = strm.next_out - out_buf;
-
-    deflateEnd(&strm);
-
-    if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
-        /* could not compress: write normal cluster */
-        bdrv_write(bs, sector_num, buf, s->cluster_sectors);
-    } else {
-        cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
-                                            out_len, 0, 0);
-        cluster_offset &= s->cluster_offset_mask;
-        if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) {
-            g_free(out_buf);
-            return -1;
-        }
-    }
-
-    g_free(out_buf);
-    return 0;
-}
-
-static void qcow_flush(BlockDriverState *bs)
-{
-    bdrv_flush(bs->file);
-}
-
-static BlockDriverAIOCB *qcow_aio_flush(BlockDriverState *bs,
-        BlockDriverCompletionFunc *cb, void *opaque)
-{
-    return bdrv_aio_flush(bs->file, cb, opaque);
-}
-
-static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
-{
-    BDRVQcowState *s = bs->opaque;
-    bdi->cluster_size = s->cluster_size;
-    return 0;
-}
-
-
-static QEMUOptionParameter qcow_create_options[] = {
-    {
-        .name = BLOCK_OPT_SIZE,
-        .type = OPT_SIZE,
-        .help = "Virtual disk size"
-    },
-    {
-        .name = BLOCK_OPT_BACKING_FILE,
-        .type = OPT_STRING,
-        .help = "File name of a base image"
-    },
-    {
-        .name = BLOCK_OPT_ENCRYPT,
-        .type = OPT_FLAG,
-        .help = "Encrypt the image"
-    },
-    { NULL }
-};
-
-static BlockDriver bdrv_qcow = {
-    .format_name	= "qcow",
-    .instance_size	= sizeof(BDRVQcowState),
-    .bdrv_probe		= qcow_probe,
-    .bdrv_open		= qcow_open,
-    .bdrv_close		= qcow_close,
-    .bdrv_create	= qcow_create,
-    .bdrv_flush		= qcow_flush,
-    .bdrv_is_allocated	= qcow_is_allocated,
-    .bdrv_set_key	= qcow_set_key,
-    .bdrv_make_empty	= qcow_make_empty,
-    .bdrv_aio_readv	= qcow_aio_readv,
-    .bdrv_aio_writev	= qcow_aio_writev,
-    .bdrv_aio_flush	= qcow_aio_flush,
-    .bdrv_write_compressed = qcow_write_compressed,
-    .bdrv_get_info	= qcow_get_info,
-
-    .create_options = qcow_create_options,
-};
-
-static void bdrv_qcow_init(void)
-{
-    bdrv_register(&bdrv_qcow);
-}
-
-block_init(bdrv_qcow_init);