xemu/block/parallels.c
Klim Kireev 555a608c5d block/parallels: check new image size
Before this patch incorrect image could be created via qemu-img
(Example: qemu-img create -f parallels -o size=4096T hack.img),
incorrect images cannot be used due to overflow in main image structure.

This patch add check of size in image creation.

After reading size it compare it with UINT32_MAX * cluster_size.

Signed-off-by: Klim Kireev <proffk@virtuozzo.mipt.ru>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Message-id: 1469639300-12155-1-git-send-email-den@openvz.org
CC: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-08-05 09:59:06 +01:00

776 lines
22 KiB
C

/*
* Block driver for Parallels disk image format
*
* Copyright (c) 2007 Alex Beregszaszi
* Copyright (c) 2015 Denis V. Lunev <den@openvz.org>
*
* This code was originally based on comparing different disk images created
* by Parallels. Currently it is based on opened OpenVZ sources
* available at
* http://git.openvz.org/?p=ploop;a=summary
*
* 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/osdep.h"
#include "qapi/error.h"
#include "qemu-common.h"
#include "block/block_int.h"
#include "sysemu/block-backend.h"
#include "qemu/module.h"
#include "qemu/bswap.h"
#include "qemu/bitmap.h"
#include "qapi/util.h"
/**************************************************************/
#define HEADER_MAGIC "WithoutFreeSpace"
#define HEADER_MAGIC2 "WithouFreSpacExt"
#define HEADER_VERSION 2
#define HEADER_INUSE_MAGIC (0x746F6E59)
#define MAX_PARALLELS_IMAGE_FACTOR (1ull << 32)
#define DEFAULT_CLUSTER_SIZE 1048576 /* 1 MiB */
// always little-endian
typedef struct ParallelsHeader {
char magic[16]; // "WithoutFreeSpace"
uint32_t version;
uint32_t heads;
uint32_t cylinders;
uint32_t tracks;
uint32_t bat_entries;
uint64_t nb_sectors;
uint32_t inuse;
uint32_t data_off;
char padding[12];
} QEMU_PACKED ParallelsHeader;
typedef enum ParallelsPreallocMode {
PRL_PREALLOC_MODE_FALLOCATE = 0,
PRL_PREALLOC_MODE_TRUNCATE = 1,
PRL_PREALLOC_MODE__MAX = 2,
} ParallelsPreallocMode;
static const char *prealloc_mode_lookup[] = {
"falloc",
"truncate",
NULL,
};
typedef struct BDRVParallelsState {
/** Locking is conservative, the lock protects
* - image file extending (truncate, fallocate)
* - any access to block allocation table
*/
CoMutex lock;
ParallelsHeader *header;
uint32_t header_size;
bool header_unclean;
unsigned long *bat_dirty_bmap;
unsigned int bat_dirty_block;
uint32_t *bat_bitmap;
unsigned int bat_size;
int64_t data_end;
uint64_t prealloc_size;
ParallelsPreallocMode prealloc_mode;
unsigned int tracks;
unsigned int off_multiplier;
} BDRVParallelsState;
#define PARALLELS_OPT_PREALLOC_MODE "prealloc-mode"
#define PARALLELS_OPT_PREALLOC_SIZE "prealloc-size"
static QemuOptsList parallels_runtime_opts = {
.name = "parallels",
.head = QTAILQ_HEAD_INITIALIZER(parallels_runtime_opts.head),
.desc = {
{
.name = PARALLELS_OPT_PREALLOC_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Preallocation size on image expansion",
.def_value_str = "128MiB",
},
{
.name = PARALLELS_OPT_PREALLOC_MODE,
.type = QEMU_OPT_STRING,
.help = "Preallocation mode on image expansion "
"(allowed values: falloc, truncate)",
.def_value_str = "falloc",
},
{ /* end of list */ },
},
};
static int64_t bat2sect(BDRVParallelsState *s, uint32_t idx)
{
return (uint64_t)le32_to_cpu(s->bat_bitmap[idx]) * s->off_multiplier;
}
static uint32_t bat_entry_off(uint32_t idx)
{
return sizeof(ParallelsHeader) + sizeof(uint32_t) * idx;
}
static int64_t seek_to_sector(BDRVParallelsState *s, int64_t sector_num)
{
uint32_t index, offset;
index = sector_num / s->tracks;
offset = sector_num % s->tracks;
/* not allocated */
if ((index >= s->bat_size) || (s->bat_bitmap[index] == 0)) {
return -1;
}
return bat2sect(s, index) + offset;
}
static int cluster_remainder(BDRVParallelsState *s, int64_t sector_num,
int nb_sectors)
{
int ret = s->tracks - sector_num % s->tracks;
return MIN(nb_sectors, ret);
}
static int64_t block_status(BDRVParallelsState *s, int64_t sector_num,
int nb_sectors, int *pnum)
{
int64_t start_off = -2, prev_end_off = -2;
*pnum = 0;
while (nb_sectors > 0 || start_off == -2) {
int64_t offset = seek_to_sector(s, sector_num);
int to_end;
if (start_off == -2) {
start_off = offset;
prev_end_off = offset;
} else if (offset != prev_end_off) {
break;
}
to_end = cluster_remainder(s, sector_num, nb_sectors);
nb_sectors -= to_end;
sector_num += to_end;
*pnum += to_end;
if (offset > 0) {
prev_end_off += to_end;
}
}
return start_off;
}
static int64_t allocate_clusters(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int *pnum)
{
BDRVParallelsState *s = bs->opaque;
uint32_t idx, to_allocate, i;
int64_t pos, space;
pos = block_status(s, sector_num, nb_sectors, pnum);
if (pos > 0) {
return pos;
}
idx = sector_num / s->tracks;
if (idx >= s->bat_size) {
return -EINVAL;
}
to_allocate = DIV_ROUND_UP(sector_num + *pnum, s->tracks) - idx;
space = to_allocate * s->tracks;
if (s->data_end + space > bdrv_getlength(bs->file->bs) >> BDRV_SECTOR_BITS) {
int ret;
space += s->prealloc_size;
if (s->prealloc_mode == PRL_PREALLOC_MODE_FALLOCATE) {
ret = bdrv_pwrite_zeroes(bs->file,
s->data_end << BDRV_SECTOR_BITS,
space << BDRV_SECTOR_BITS, 0);
} else {
ret = bdrv_truncate(bs->file->bs,
(s->data_end + space) << BDRV_SECTOR_BITS);
}
if (ret < 0) {
return ret;
}
}
for (i = 0; i < to_allocate; i++) {
s->bat_bitmap[idx + i] = cpu_to_le32(s->data_end / s->off_multiplier);
s->data_end += s->tracks;
bitmap_set(s->bat_dirty_bmap,
bat_entry_off(idx + i) / s->bat_dirty_block, 1);
}
return bat2sect(s, idx) + sector_num % s->tracks;
}
static coroutine_fn int parallels_co_flush_to_os(BlockDriverState *bs)
{
BDRVParallelsState *s = bs->opaque;
unsigned long size = DIV_ROUND_UP(s->header_size, s->bat_dirty_block);
unsigned long bit;
qemu_co_mutex_lock(&s->lock);
bit = find_first_bit(s->bat_dirty_bmap, size);
while (bit < size) {
uint32_t off = bit * s->bat_dirty_block;
uint32_t to_write = s->bat_dirty_block;
int ret;
if (off + to_write > s->header_size) {
to_write = s->header_size - off;
}
ret = bdrv_pwrite(bs->file, off, (uint8_t *)s->header + off,
to_write);
if (ret < 0) {
qemu_co_mutex_unlock(&s->lock);
return ret;
}
bit = find_next_bit(s->bat_dirty_bmap, size, bit + 1);
}
bitmap_zero(s->bat_dirty_bmap, size);
qemu_co_mutex_unlock(&s->lock);
return 0;
}
static int64_t coroutine_fn parallels_co_get_block_status(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file)
{
BDRVParallelsState *s = bs->opaque;
int64_t offset;
qemu_co_mutex_lock(&s->lock);
offset = block_status(s, sector_num, nb_sectors, pnum);
qemu_co_mutex_unlock(&s->lock);
if (offset < 0) {
return 0;
}
*file = bs->file->bs;
return (offset << BDRV_SECTOR_BITS) |
BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
}
static coroutine_fn int parallels_co_writev(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
{
BDRVParallelsState *s = bs->opaque;
uint64_t bytes_done = 0;
QEMUIOVector hd_qiov;
int ret = 0;
qemu_iovec_init(&hd_qiov, qiov->niov);
while (nb_sectors > 0) {
int64_t position;
int n, nbytes;
qemu_co_mutex_lock(&s->lock);
position = allocate_clusters(bs, sector_num, nb_sectors, &n);
qemu_co_mutex_unlock(&s->lock);
if (position < 0) {
ret = (int)position;
break;
}
nbytes = n << BDRV_SECTOR_BITS;
qemu_iovec_reset(&hd_qiov);
qemu_iovec_concat(&hd_qiov, qiov, bytes_done, nbytes);
ret = bdrv_co_writev(bs->file, position, n, &hd_qiov);
if (ret < 0) {
break;
}
nb_sectors -= n;
sector_num += n;
bytes_done += nbytes;
}
qemu_iovec_destroy(&hd_qiov);
return ret;
}
static coroutine_fn int parallels_co_readv(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
{
BDRVParallelsState *s = bs->opaque;
uint64_t bytes_done = 0;
QEMUIOVector hd_qiov;
int ret = 0;
qemu_iovec_init(&hd_qiov, qiov->niov);
while (nb_sectors > 0) {
int64_t position;
int n, nbytes;
qemu_co_mutex_lock(&s->lock);
position = block_status(s, sector_num, nb_sectors, &n);
qemu_co_mutex_unlock(&s->lock);
nbytes = n << BDRV_SECTOR_BITS;
if (position < 0) {
qemu_iovec_memset(qiov, bytes_done, 0, nbytes);
} else {
qemu_iovec_reset(&hd_qiov);
qemu_iovec_concat(&hd_qiov, qiov, bytes_done, nbytes);
ret = bdrv_co_readv(bs->file, position, n, &hd_qiov);
if (ret < 0) {
break;
}
}
nb_sectors -= n;
sector_num += n;
bytes_done += nbytes;
}
qemu_iovec_destroy(&hd_qiov);
return ret;
}
static int parallels_check(BlockDriverState *bs, BdrvCheckResult *res,
BdrvCheckMode fix)
{
BDRVParallelsState *s = bs->opaque;
int64_t size, prev_off, high_off;
int ret;
uint32_t i;
bool flush_bat = false;
int cluster_size = s->tracks << BDRV_SECTOR_BITS;
size = bdrv_getlength(bs->file->bs);
if (size < 0) {
res->check_errors++;
return size;
}
if (s->header_unclean) {
fprintf(stderr, "%s image was not closed correctly\n",
fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR");
res->corruptions++;
if (fix & BDRV_FIX_ERRORS) {
/* parallels_close will do the job right */
res->corruptions_fixed++;
s->header_unclean = false;
}
}
res->bfi.total_clusters = s->bat_size;
res->bfi.compressed_clusters = 0; /* compression is not supported */
high_off = 0;
prev_off = 0;
for (i = 0; i < s->bat_size; i++) {
int64_t off = bat2sect(s, i) << BDRV_SECTOR_BITS;
if (off == 0) {
prev_off = 0;
continue;
}
/* cluster outside the image */
if (off > size) {
fprintf(stderr, "%s cluster %u is outside image\n",
fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i);
res->corruptions++;
if (fix & BDRV_FIX_ERRORS) {
prev_off = 0;
s->bat_bitmap[i] = 0;
res->corruptions_fixed++;
flush_bat = true;
continue;
}
}
res->bfi.allocated_clusters++;
if (off > high_off) {
high_off = off;
}
if (prev_off != 0 && (prev_off + cluster_size) != off) {
res->bfi.fragmented_clusters++;
}
prev_off = off;
}
if (flush_bat) {
ret = bdrv_pwrite_sync(bs->file, 0, s->header, s->header_size);
if (ret < 0) {
res->check_errors++;
return ret;
}
}
res->image_end_offset = high_off + cluster_size;
if (size > res->image_end_offset) {
int64_t count;
count = DIV_ROUND_UP(size - res->image_end_offset, cluster_size);
fprintf(stderr, "%s space leaked at the end of the image %" PRId64 "\n",
fix & BDRV_FIX_LEAKS ? "Repairing" : "ERROR",
size - res->image_end_offset);
res->leaks += count;
if (fix & BDRV_FIX_LEAKS) {
ret = bdrv_truncate(bs->file->bs, res->image_end_offset);
if (ret < 0) {
res->check_errors++;
return ret;
}
res->leaks_fixed += count;
}
}
return 0;
}
static int parallels_create(const char *filename, QemuOpts *opts, Error **errp)
{
int64_t total_size, cl_size;
uint8_t tmp[BDRV_SECTOR_SIZE];
Error *local_err = NULL;
BlockBackend *file;
uint32_t bat_entries, bat_sectors;
ParallelsHeader header;
int ret;
total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
BDRV_SECTOR_SIZE);
cl_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE,
DEFAULT_CLUSTER_SIZE), BDRV_SECTOR_SIZE);
if (total_size >= MAX_PARALLELS_IMAGE_FACTOR * cl_size) {
error_propagate(errp, local_err);
return -E2BIG;
}
ret = bdrv_create_file(filename, opts, &local_err);
if (ret < 0) {
error_propagate(errp, local_err);
return ret;
}
file = blk_new_open(filename, NULL, NULL,
BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
if (file == NULL) {
error_propagate(errp, local_err);
return -EIO;
}
blk_set_allow_write_beyond_eof(file, true);
ret = blk_truncate(file, 0);
if (ret < 0) {
goto exit;
}
bat_entries = DIV_ROUND_UP(total_size, cl_size);
bat_sectors = DIV_ROUND_UP(bat_entry_off(bat_entries), cl_size);
bat_sectors = (bat_sectors * cl_size) >> BDRV_SECTOR_BITS;
memset(&header, 0, sizeof(header));
memcpy(header.magic, HEADER_MAGIC2, sizeof(header.magic));
header.version = cpu_to_le32(HEADER_VERSION);
/* don't care much about geometry, it is not used on image level */
header.heads = cpu_to_le32(16);
header.cylinders = cpu_to_le32(total_size / BDRV_SECTOR_SIZE / 16 / 32);
header.tracks = cpu_to_le32(cl_size >> BDRV_SECTOR_BITS);
header.bat_entries = cpu_to_le32(bat_entries);
header.nb_sectors = cpu_to_le64(DIV_ROUND_UP(total_size, BDRV_SECTOR_SIZE));
header.data_off = cpu_to_le32(bat_sectors);
/* write all the data */
memset(tmp, 0, sizeof(tmp));
memcpy(tmp, &header, sizeof(header));
ret = blk_pwrite(file, 0, tmp, BDRV_SECTOR_SIZE, 0);
if (ret < 0) {
goto exit;
}
ret = blk_pwrite_zeroes(file, BDRV_SECTOR_SIZE,
(bat_sectors - 1) << BDRV_SECTOR_BITS, 0);
if (ret < 0) {
goto exit;
}
ret = 0;
done:
blk_unref(file);
return ret;
exit:
error_setg_errno(errp, -ret, "Failed to create Parallels image");
goto done;
}
static int parallels_probe(const uint8_t *buf, int buf_size,
const char *filename)
{
const ParallelsHeader *ph = (const void *)buf;
if (buf_size < sizeof(ParallelsHeader)) {
return 0;
}
if ((!memcmp(ph->magic, HEADER_MAGIC, 16) ||
!memcmp(ph->magic, HEADER_MAGIC2, 16)) &&
(le32_to_cpu(ph->version) == HEADER_VERSION)) {
return 100;
}
return 0;
}
static int parallels_update_header(BlockDriverState *bs)
{
BDRVParallelsState *s = bs->opaque;
unsigned size = MAX(bdrv_opt_mem_align(bs->file->bs),
sizeof(ParallelsHeader));
if (size > s->header_size) {
size = s->header_size;
}
return bdrv_pwrite_sync(bs->file, 0, s->header, size);
}
static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVParallelsState *s = bs->opaque;
ParallelsHeader ph;
int ret, size, i;
QemuOpts *opts = NULL;
Error *local_err = NULL;
char *buf;
ret = bdrv_pread(bs->file, 0, &ph, sizeof(ph));
if (ret < 0) {
goto fail;
}
bs->total_sectors = le64_to_cpu(ph.nb_sectors);
if (le32_to_cpu(ph.version) != HEADER_VERSION) {
goto fail_format;
}
if (!memcmp(ph.magic, HEADER_MAGIC, 16)) {
s->off_multiplier = 1;
bs->total_sectors = 0xffffffff & bs->total_sectors;
} else if (!memcmp(ph.magic, HEADER_MAGIC2, 16)) {
s->off_multiplier = le32_to_cpu(ph.tracks);
} else {
goto fail_format;
}
s->tracks = le32_to_cpu(ph.tracks);
if (s->tracks == 0) {
error_setg(errp, "Invalid image: Zero sectors per track");
ret = -EINVAL;
goto fail;
}
if (s->tracks > INT32_MAX/513) {
error_setg(errp, "Invalid image: Too big cluster");
ret = -EFBIG;
goto fail;
}
s->bat_size = le32_to_cpu(ph.bat_entries);
if (s->bat_size > INT_MAX / sizeof(uint32_t)) {
error_setg(errp, "Catalog too large");
ret = -EFBIG;
goto fail;
}
size = bat_entry_off(s->bat_size);
s->header_size = ROUND_UP(size, bdrv_opt_mem_align(bs->file->bs));
s->header = qemu_try_blockalign(bs->file->bs, s->header_size);
if (s->header == NULL) {
ret = -ENOMEM;
goto fail;
}
s->data_end = le32_to_cpu(ph.data_off);
if (s->data_end == 0) {
s->data_end = ROUND_UP(bat_entry_off(s->bat_size), BDRV_SECTOR_SIZE);
}
if (s->data_end < s->header_size) {
/* there is not enough unused space to fit to block align between BAT
and actual data. We can't avoid read-modify-write... */
s->header_size = size;
}
ret = bdrv_pread(bs->file, 0, s->header, s->header_size);
if (ret < 0) {
goto fail;
}
s->bat_bitmap = (uint32_t *)(s->header + 1);
for (i = 0; i < s->bat_size; i++) {
int64_t off = bat2sect(s, i);
if (off >= s->data_end) {
s->data_end = off + s->tracks;
}
}
if (le32_to_cpu(ph.inuse) == HEADER_INUSE_MAGIC) {
/* Image was not closed correctly. The check is mandatory */
s->header_unclean = true;
if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) {
error_setg(errp, "parallels: Image was not closed correctly; "
"cannot be opened read/write");
ret = -EACCES;
goto fail;
}
}
opts = qemu_opts_create(&parallels_runtime_opts, NULL, 0, &local_err);
if (local_err != NULL) {
goto fail_options;
}
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err != NULL) {
goto fail_options;
}
s->prealloc_size =
qemu_opt_get_size_del(opts, PARALLELS_OPT_PREALLOC_SIZE, 0);
s->prealloc_size = MAX(s->tracks, s->prealloc_size >> BDRV_SECTOR_BITS);
buf = qemu_opt_get_del(opts, PARALLELS_OPT_PREALLOC_MODE);
s->prealloc_mode = qapi_enum_parse(prealloc_mode_lookup, buf,
PRL_PREALLOC_MODE__MAX, PRL_PREALLOC_MODE_FALLOCATE, &local_err);
g_free(buf);
if (local_err != NULL) {
goto fail_options;
}
if (!bdrv_has_zero_init(bs->file->bs) ||
bdrv_truncate(bs->file->bs, bdrv_getlength(bs->file->bs)) != 0) {
s->prealloc_mode = PRL_PREALLOC_MODE_FALLOCATE;
}
if (flags & BDRV_O_RDWR) {
s->header->inuse = cpu_to_le32(HEADER_INUSE_MAGIC);
ret = parallels_update_header(bs);
if (ret < 0) {
goto fail;
}
}
s->bat_dirty_block = 4 * getpagesize();
s->bat_dirty_bmap =
bitmap_new(DIV_ROUND_UP(s->header_size, s->bat_dirty_block));
qemu_co_mutex_init(&s->lock);
return 0;
fail_format:
error_setg(errp, "Image not in Parallels format");
ret = -EINVAL;
fail:
qemu_vfree(s->header);
return ret;
fail_options:
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
static void parallels_close(BlockDriverState *bs)
{
BDRVParallelsState *s = bs->opaque;
if (bs->open_flags & BDRV_O_RDWR) {
s->header->inuse = 0;
parallels_update_header(bs);
}
if (bs->open_flags & BDRV_O_RDWR) {
bdrv_truncate(bs->file->bs, s->data_end << BDRV_SECTOR_BITS);
}
g_free(s->bat_dirty_bmap);
qemu_vfree(s->header);
}
static QemuOptsList parallels_create_opts = {
.name = "parallels-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(parallels_create_opts.head),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size",
},
{
.name = BLOCK_OPT_CLUSTER_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Parallels image cluster size",
.def_value_str = stringify(DEFAULT_CLUSTER_SIZE),
},
{ /* end of list */ }
}
};
static BlockDriver bdrv_parallels = {
.format_name = "parallels",
.instance_size = sizeof(BDRVParallelsState),
.bdrv_probe = parallels_probe,
.bdrv_open = parallels_open,
.bdrv_close = parallels_close,
.bdrv_co_get_block_status = parallels_co_get_block_status,
.bdrv_has_zero_init = bdrv_has_zero_init_1,
.bdrv_co_flush_to_os = parallels_co_flush_to_os,
.bdrv_co_readv = parallels_co_readv,
.bdrv_co_writev = parallels_co_writev,
.bdrv_create = parallels_create,
.bdrv_check = parallels_check,
.create_opts = &parallels_create_opts,
};
static void bdrv_parallels_init(void)
{
bdrv_register(&bdrv_parallels);
}
block_init(bdrv_parallels_init);