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qemu/block/vdi.c
David Edmondson 07ee2ab4fd block/vdi: Don't assume that blocks are larger than VdiHeader 
Given that the block size is read from the header of the VDI file, a
wide variety of sizes might be seen. Rather than re-using a block
sized memory region when writing the VDI header, allocate an
appropriately sized buffer.

Signed-off-by: David Edmondson <david.edmondson@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Max Reitz <mreitz@redhat.com>
Message-id: 20210325112941.365238-3-pbonzini@redhat.com
Message-Id: <20210309144015.557477-3-david.edmondson@oracle.com>
Acked-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-03-31 10:44:21 +01:00

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/*
* Block driver for the Virtual Disk Image (VDI) format
*
* Copyright (c) 2009, 2012 Stefan Weil
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) version 3 or any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Reference:
* http://forums.virtualbox.org/viewtopic.php?t=8046
*
* This driver supports create / read / write operations on VDI images.
*
* Todo (see also TODO in code):
*
* Some features like snapshots are still missing.
*
* Deallocation of zero-filled blocks and shrinking images are missing, too
* (might be added to common block layer).
*
* Allocation of blocks could be optimized (less writes to block map and
* header).
*
* Read and write of adjacent blocks could be done in one operation
* (current code uses one operation per block (1 MiB).
*
* The code is not thread safe (missing locks for changes in header and
* block table, no problem with current QEMU).
*
* Hints:
*
* Blocks (VDI documentation) correspond to clusters (QEMU).
* QEMU's backing files could be implemented using VDI snapshot files (TODO).
* VDI snapshot files may also contain the complete machine state.
* Maybe this machine state can be converted to QEMU PC machine snapshot data.
*
* The driver keeps a block cache (little endian entries) in memory.
* For the standard block size (1 MiB), a 1 TiB disk will use 4 MiB RAM,
* so this seems to be reasonable.
*/
#include "qemu/osdep.h"
#include "qemu/units.h"
#include "qapi/error.h"
#include "qapi/qobject-input-visitor.h"
#include "qapi/qapi-visit-block-core.h"
#include "block/block_int.h"
#include "block/qdict.h"
#include "sysemu/block-backend.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include "qemu/bswap.h"
#include "migration/blocker.h"
#include "qemu/coroutine.h"
#include "qemu/cutils.h"
#include "qemu/uuid.h"
/* Code configuration options. */
/* Enable debug messages. */
//~ #define CONFIG_VDI_DEBUG
/* Support write operations on VDI images. */
#define CONFIG_VDI_WRITE
/* Support non-standard block (cluster) size. This is untested.
* Maybe it will be needed for very large images.
*/
//~ #define CONFIG_VDI_BLOCK_SIZE
/* Support static (fixed, pre-allocated) images. */
#define CONFIG_VDI_STATIC_IMAGE
/* Command line option for static images. */
#define BLOCK_OPT_STATIC "static"
#define SECTOR_SIZE 512
#define DEFAULT_CLUSTER_SIZE 1048576
/* Note: can't use 1 * MiB, because it's passed to stringify() */
#if defined(CONFIG_VDI_DEBUG)
#define VDI_DEBUG 1
#else
#define VDI_DEBUG 0
#endif
#define logout(fmt, ...) \
do { \
if (VDI_DEBUG) { \
fprintf(stderr, "vdi\t%-24s" fmt, __func__, ##__VA_ARGS__); \
} \
} while (0)
/* Image signature. */
#define VDI_SIGNATURE 0xbeda107f
/* Image version. */
#define VDI_VERSION_1_1 0x00010001
/* Image type. */
#define VDI_TYPE_DYNAMIC 1
#define VDI_TYPE_STATIC 2
/* Innotek / SUN images use these strings in header.text:
* "<<< innotek VirtualBox Disk Image >>>\n"
* "<<< Sun xVM VirtualBox Disk Image >>>\n"
* "<<< Sun VirtualBox Disk Image >>>\n"
* The value does not matter, so QEMU created images use a different text.
*/
#define VDI_TEXT "<<< QEMU VM Virtual Disk Image >>>\n"
/* A never-allocated block; semantically arbitrary content. */
#define VDI_UNALLOCATED 0xffffffffU
/* A discarded (no longer allocated) block; semantically zero-filled. */
#define VDI_DISCARDED 0xfffffffeU
#define VDI_IS_ALLOCATED(X) ((X) < VDI_DISCARDED)
/* The bmap will take up VDI_BLOCKS_IN_IMAGE_MAX * sizeof(uint32_t) bytes; since
* the bmap is read and written in a single operation, its size needs to be
* limited to INT_MAX; furthermore, when opening an image, the bmap size is
* rounded up to be aligned on BDRV_SECTOR_SIZE.
* Therefore this should satisfy the following:
* VDI_BLOCKS_IN_IMAGE_MAX * sizeof(uint32_t) + BDRV_SECTOR_SIZE == INT_MAX + 1
* (INT_MAX + 1 is the first value not representable as an int)
* This guarantees that any value below or equal to the constant will, when
* multiplied by sizeof(uint32_t) and rounded up to a BDRV_SECTOR_SIZE boundary,
* still be below or equal to INT_MAX. */
#define VDI_BLOCKS_IN_IMAGE_MAX \
((unsigned)((INT_MAX + 1u - BDRV_SECTOR_SIZE) / sizeof(uint32_t)))
#define VDI_DISK_SIZE_MAX ((uint64_t)VDI_BLOCKS_IN_IMAGE_MAX * \
(uint64_t)DEFAULT_CLUSTER_SIZE)
static QemuOptsList vdi_create_opts;
typedef struct {
char text[0x40];
uint32_t signature;
uint32_t version;
uint32_t header_size;
uint32_t image_type;
uint32_t image_flags;
char description[256];
uint32_t offset_bmap;
uint32_t offset_data;
uint32_t cylinders; /* disk geometry, unused here */
uint32_t heads; /* disk geometry, unused here */
uint32_t sectors; /* disk geometry, unused here */
uint32_t sector_size;
uint32_t unused1;
uint64_t disk_size;
uint32_t block_size;
uint32_t block_extra; /* unused here */
uint32_t blocks_in_image;
uint32_t blocks_allocated;
QemuUUID uuid_image;
QemuUUID uuid_last_snap;
QemuUUID uuid_link;
QemuUUID uuid_parent;
uint64_t unused2[7];
} QEMU_PACKED VdiHeader;
QEMU_BUILD_BUG_ON(sizeof(VdiHeader) != 512);
typedef struct {
/* The block map entries are little endian (even in memory). */
uint32_t *bmap;
/* Size of block (bytes). */
uint32_t block_size;
/* First sector of block map. */
uint32_t bmap_sector;
/* VDI header (converted to host endianness). */
VdiHeader header;
CoRwlock bmap_lock;
Error *migration_blocker;
} BDRVVdiState;
static void vdi_header_to_cpu(VdiHeader *header)
{
header->signature = le32_to_cpu(header->signature);
header->version = le32_to_cpu(header->version);
header->header_size = le32_to_cpu(header->header_size);
header->image_type = le32_to_cpu(header->image_type);
header->image_flags = le32_to_cpu(header->image_flags);
header->offset_bmap = le32_to_cpu(header->offset_bmap);
header->offset_data = le32_to_cpu(header->offset_data);
header->cylinders = le32_to_cpu(header->cylinders);
header->heads = le32_to_cpu(header->heads);
header->sectors = le32_to_cpu(header->sectors);
header->sector_size = le32_to_cpu(header->sector_size);
header->disk_size = le64_to_cpu(header->disk_size);
header->block_size = le32_to_cpu(header->block_size);
header->block_extra = le32_to_cpu(header->block_extra);
header->blocks_in_image = le32_to_cpu(header->blocks_in_image);
header->blocks_allocated = le32_to_cpu(header->blocks_allocated);
header->uuid_image = qemu_uuid_bswap(header->uuid_image);
header->uuid_last_snap = qemu_uuid_bswap(header->uuid_last_snap);
header->uuid_link = qemu_uuid_bswap(header->uuid_link);
header->uuid_parent = qemu_uuid_bswap(header->uuid_parent);
}
static void vdi_header_to_le(VdiHeader *header)
{
header->signature = cpu_to_le32(header->signature);
header->version = cpu_to_le32(header->version);
header->header_size = cpu_to_le32(header->header_size);
header->image_type = cpu_to_le32(header->image_type);
header->image_flags = cpu_to_le32(header->image_flags);
header->offset_bmap = cpu_to_le32(header->offset_bmap);
header->offset_data = cpu_to_le32(header->offset_data);
header->cylinders = cpu_to_le32(header->cylinders);
header->heads = cpu_to_le32(header->heads);
header->sectors = cpu_to_le32(header->sectors);
header->sector_size = cpu_to_le32(header->sector_size);
header->disk_size = cpu_to_le64(header->disk_size);
header->block_size = cpu_to_le32(header->block_size);
header->block_extra = cpu_to_le32(header->block_extra);
header->blocks_in_image = cpu_to_le32(header->blocks_in_image);
header->blocks_allocated = cpu_to_le32(header->blocks_allocated);
header->uuid_image = qemu_uuid_bswap(header->uuid_image);
header->uuid_last_snap = qemu_uuid_bswap(header->uuid_last_snap);
header->uuid_link = qemu_uuid_bswap(header->uuid_link);
header->uuid_parent = qemu_uuid_bswap(header->uuid_parent);
}
static void vdi_header_print(VdiHeader *header)
{
char uuidstr[37];
QemuUUID uuid;
logout("text %s", header->text);
logout("signature 0x%08x\n", header->signature);
logout("header size 0x%04x\n", header->header_size);
logout("image type 0x%04x\n", header->image_type);
logout("image flags 0x%04x\n", header->image_flags);
logout("description %s\n", header->description);
logout("offset bmap 0x%04x\n", header->offset_bmap);
logout("offset data 0x%04x\n", header->offset_data);
logout("cylinders 0x%04x\n", header->cylinders);
logout("heads 0x%04x\n", header->heads);
logout("sectors 0x%04x\n", header->sectors);
logout("sector size 0x%04x\n", header->sector_size);
logout("image size 0x%" PRIx64 " B (%" PRIu64 " MiB)\n",
header->disk_size, header->disk_size / MiB);
logout("block size 0x%04x\n", header->block_size);
logout("block extra 0x%04x\n", header->block_extra);
logout("blocks tot. 0x%04x\n", header->blocks_in_image);
logout("blocks all. 0x%04x\n", header->blocks_allocated);
uuid = header->uuid_image;
qemu_uuid_unparse(&uuid, uuidstr);
logout("uuid image %s\n", uuidstr);
uuid = header->uuid_last_snap;
qemu_uuid_unparse(&uuid, uuidstr);
logout("uuid snap %s\n", uuidstr);
uuid = header->uuid_link;
qemu_uuid_unparse(&uuid, uuidstr);
logout("uuid link %s\n", uuidstr);
uuid = header->uuid_parent;
qemu_uuid_unparse(&uuid, uuidstr);
logout("uuid parent %s\n", uuidstr);
}
static int coroutine_fn vdi_co_check(BlockDriverState *bs, BdrvCheckResult *res,
BdrvCheckMode fix)
{
/* TODO: additional checks possible. */
BDRVVdiState *s = (BDRVVdiState *)bs->opaque;
uint32_t blocks_allocated = 0;
uint32_t block;
uint32_t *bmap;
logout("\n");
if (fix) {
return -ENOTSUP;
}
bmap = g_try_new(uint32_t, s->header.blocks_in_image);
if (s->header.blocks_in_image && bmap == NULL) {
res->check_errors++;
return -ENOMEM;
}
memset(bmap, 0xff, s->header.blocks_in_image * sizeof(uint32_t));
/* Check block map and value of blocks_allocated. */
for (block = 0; block < s->header.blocks_in_image; block++) {
uint32_t bmap_entry = le32_to_cpu(s->bmap[block]);
if (VDI_IS_ALLOCATED(bmap_entry)) {
if (bmap_entry < s->header.blocks_in_image) {
blocks_allocated++;
if (!VDI_IS_ALLOCATED(bmap[bmap_entry])) {
bmap[bmap_entry] = bmap_entry;
} else {
fprintf(stderr, "ERROR: block index %" PRIu32
" also used by %" PRIu32 "\n", bmap[bmap_entry], bmap_entry);
res->corruptions++;
}
} else {
fprintf(stderr, "ERROR: block index %" PRIu32
" too large, is %" PRIu32 "\n", block, bmap_entry);
res->corruptions++;
}
}
}
if (blocks_allocated != s->header.blocks_allocated) {
fprintf(stderr, "ERROR: allocated blocks mismatch, is %" PRIu32
", should be %" PRIu32 "\n",
blocks_allocated, s->header.blocks_allocated);
res->corruptions++;
}
g_free(bmap);
return 0;
}
static int vdi_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
/* TODO: vdi_get_info would be needed for machine snapshots.
vm_state_offset is still missing. */
BDRVVdiState *s = (BDRVVdiState *)bs->opaque;
logout("\n");
bdi->cluster_size = s->block_size;
bdi->vm_state_offset = 0;
return 0;
}
static int vdi_make_empty(BlockDriverState *bs)
{
/* TODO: missing code. */
logout("\n");
/* The return value for missing code must be 0, see block.c. */
return 0;
}
static int vdi_probe(const uint8_t *buf, int buf_size, const char *filename)
{
const VdiHeader *header = (const VdiHeader *)buf;
int ret = 0;
logout("\n");
if (buf_size < sizeof(*header)) {
/* Header too small, no VDI. */
} else if (le32_to_cpu(header->signature) == VDI_SIGNATURE) {
ret = 100;
}
if (ret == 0) {
logout("no vdi image\n");
} else {
logout("%s", header->text);
}
return ret;
}
static int vdi_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVVdiState *s = bs->opaque;
VdiHeader header;
size_t bmap_size;
int ret;
QemuUUID uuid_link, uuid_parent;
bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
BDRV_CHILD_IMAGE, false, errp);
if (!bs->file) {
return -EINVAL;
}
logout("\n");
ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
if (ret < 0) {
goto fail;
}
vdi_header_to_cpu(&header);
if (VDI_DEBUG) {
vdi_header_print(&header);
}
if (header.disk_size > VDI_DISK_SIZE_MAX) {
error_setg(errp, "Unsupported VDI image size (size is 0x%" PRIx64
", max supported is 0x%" PRIx64 ")",
header.disk_size, VDI_DISK_SIZE_MAX);
ret = -ENOTSUP;
goto fail;
}
uuid_link = header.uuid_link;
uuid_parent = header.uuid_parent;
if (header.disk_size % SECTOR_SIZE != 0) {
/* 'VBoxManage convertfromraw' can create images with odd disk sizes.
We accept them but round the disk size to the next multiple of
SECTOR_SIZE. */
logout("odd disk size %" PRIu64 " B, round up\n", header.disk_size);
header.disk_size = ROUND_UP(header.disk_size, SECTOR_SIZE);
}
if (header.signature != VDI_SIGNATURE) {
error_setg(errp, "Image not in VDI format (bad signature %08" PRIx32
")", header.signature);
ret = -EINVAL;
goto fail;
} else if (header.version != VDI_VERSION_1_1) {
error_setg(errp, "unsupported VDI image (version %" PRIu32 ".%" PRIu32
")", header.version >> 16, header.version & 0xffff);
ret = -ENOTSUP;
goto fail;
} else if (header.offset_bmap % SECTOR_SIZE != 0) {
/* We only support block maps which start on a sector boundary. */
error_setg(errp, "unsupported VDI image (unaligned block map offset "
"0x%" PRIx32 ")", header.offset_bmap);
ret = -ENOTSUP;
goto fail;
} else if (header.offset_data % SECTOR_SIZE != 0) {
/* We only support data blocks which start on a sector boundary. */
error_setg(errp, "unsupported VDI image (unaligned data offset 0x%"
PRIx32 ")", header.offset_data);
ret = -ENOTSUP;
goto fail;
} else if (header.sector_size != SECTOR_SIZE) {
error_setg(errp, "unsupported VDI image (sector size %" PRIu32
" is not %u)", header.sector_size, SECTOR_SIZE);
ret = -ENOTSUP;
goto fail;
} else if (header.block_size != DEFAULT_CLUSTER_SIZE) {
error_setg(errp, "unsupported VDI image (block size %" PRIu32
" is not %" PRIu32 ")",
header.block_size, DEFAULT_CLUSTER_SIZE);
ret = -ENOTSUP;
goto fail;
} else if (header.disk_size >
(uint64_t)header.blocks_in_image * header.block_size) {
error_setg(errp, "unsupported VDI image (disk size %" PRIu64 ", "
"image bitmap has room for %" PRIu64 ")",
header.disk_size,
(uint64_t)header.blocks_in_image * header.block_size);
ret = -ENOTSUP;
goto fail;
} else if (!qemu_uuid_is_null(&uuid_link)) {
error_setg(errp, "unsupported VDI image (non-NULL link UUID)");
ret = -ENOTSUP;
goto fail;
} else if (!qemu_uuid_is_null(&uuid_parent)) {
error_setg(errp, "unsupported VDI image (non-NULL parent UUID)");
ret = -ENOTSUP;
goto fail;
} else if (header.blocks_in_image > VDI_BLOCKS_IN_IMAGE_MAX) {
error_setg(errp, "unsupported VDI image "
"(too many blocks %u, max is %u)",
header.blocks_in_image, VDI_BLOCKS_IN_IMAGE_MAX);
ret = -ENOTSUP;
goto fail;
}
bs->total_sectors = header.disk_size / SECTOR_SIZE;
s->block_size = header.block_size;
s->bmap_sector = header.offset_bmap / SECTOR_SIZE;
s->header = header;
bmap_size = header.blocks_in_image * sizeof(uint32_t);
bmap_size = DIV_ROUND_UP(bmap_size, SECTOR_SIZE);
s->bmap = qemu_try_blockalign(bs->file->bs, bmap_size * SECTOR_SIZE);
if (s->bmap == NULL) {
ret = -ENOMEM;
goto fail;
}
ret = bdrv_pread(bs->file, header.offset_bmap, s->bmap,
bmap_size * SECTOR_SIZE);
if (ret < 0) {
goto fail_free_bmap;
}
/* Disable migration when vdi images are used */
error_setg(&s->migration_blocker, "The vdi format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
ret = migrate_add_blocker(s->migration_blocker, errp);
if (ret < 0) {
error_free(s->migration_blocker);
goto fail_free_bmap;
}
qemu_co_rwlock_init(&s->bmap_lock);
return 0;
fail_free_bmap:
qemu_vfree(s->bmap);
fail:
return ret;
}
static int vdi_reopen_prepare(BDRVReopenState *state,
BlockReopenQueue *queue, Error **errp)
{
return 0;
}
static int coroutine_fn vdi_co_block_status(BlockDriverState *bs,
bool want_zero,
int64_t offset, int64_t bytes,
int64_t *pnum, int64_t *map,
BlockDriverState **file)
{
BDRVVdiState *s = (BDRVVdiState *)bs->opaque;
size_t bmap_index = offset / s->block_size;
size_t index_in_block = offset % s->block_size;
uint32_t bmap_entry = le32_to_cpu(s->bmap[bmap_index]);
int result;
logout("%p, %" PRId64 ", %" PRId64 ", %p\n", bs, offset, bytes, pnum);
*pnum = MIN(s->block_size - index_in_block, bytes);
result = VDI_IS_ALLOCATED(bmap_entry);
if (!result) {
return BDRV_BLOCK_ZERO;
}
*map = s->header.offset_data + (uint64_t)bmap_entry * s->block_size +
index_in_block;
*file = bs->file->bs;
return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID |
(s->header.image_type == VDI_TYPE_STATIC ? BDRV_BLOCK_RECURSE : 0);
}
static int coroutine_fn
vdi_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags)
{
BDRVVdiState *s = bs->opaque;
QEMUIOVector local_qiov;
uint32_t bmap_entry;
uint32_t block_index;
uint32_t offset_in_block;
uint32_t n_bytes;
uint64_t bytes_done = 0;
int ret = 0;
logout("\n");
qemu_iovec_init(&local_qiov, qiov->niov);
while (ret >= 0 && bytes > 0) {
block_index = offset / s->block_size;
offset_in_block = offset % s->block_size;
n_bytes = MIN(bytes, s->block_size - offset_in_block);
logout("will read %u bytes starting at offset %" PRIu64 "\n",
n_bytes, offset);
/* prepare next AIO request */
qemu_co_rwlock_rdlock(&s->bmap_lock);
bmap_entry = le32_to_cpu(s->bmap[block_index]);
qemu_co_rwlock_unlock(&s->bmap_lock);
if (!VDI_IS_ALLOCATED(bmap_entry)) {
/* Block not allocated, return zeros, no need to wait. */
qemu_iovec_memset(qiov, bytes_done, 0, n_bytes);
ret = 0;
} else {
uint64_t data_offset = s->header.offset_data +
(uint64_t)bmap_entry * s->block_size +
offset_in_block;
qemu_iovec_reset(&local_qiov);
qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes);
ret = bdrv_co_preadv(bs->file, data_offset, n_bytes,
&local_qiov, 0);
}
logout("%u bytes read\n", n_bytes);
bytes -= n_bytes;
offset += n_bytes;
bytes_done += n_bytes;
}
qemu_iovec_destroy(&local_qiov);
return ret;
}
static int coroutine_fn
vdi_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags)
{
BDRVVdiState *s = bs->opaque;
QEMUIOVector local_qiov;
uint32_t bmap_entry;
uint32_t block_index;
uint32_t offset_in_block;
uint32_t n_bytes;
uint64_t data_offset;
uint32_t bmap_first = VDI_UNALLOCATED;
uint32_t bmap_last = VDI_UNALLOCATED;
uint8_t *block = NULL;
uint64_t bytes_done = 0;
int ret = 0;
logout("\n");
qemu_iovec_init(&local_qiov, qiov->niov);
while (ret >= 0 && bytes > 0) {
block_index = offset / s->block_size;
offset_in_block = offset % s->block_size;
n_bytes = MIN(bytes, s->block_size - offset_in_block);
logout("will write %u bytes starting at offset %" PRIu64 "\n",
n_bytes, offset);
/* prepare next AIO request */
qemu_co_rwlock_rdlock(&s->bmap_lock);
bmap_entry = le32_to_cpu(s->bmap[block_index]);
if (!VDI_IS_ALLOCATED(bmap_entry)) {
/* Allocate new block and write to it. */
uint64_t data_offset;
qemu_co_rwlock_upgrade(&s->bmap_lock);
bmap_entry = le32_to_cpu(s->bmap[block_index]);
if (VDI_IS_ALLOCATED(bmap_entry)) {
/* A concurrent allocation did the work for us. */
qemu_co_rwlock_downgrade(&s->bmap_lock);
goto nonallocating_write;
}
bmap_entry = s->header.blocks_allocated;
s->bmap[block_index] = cpu_to_le32(bmap_entry);
s->header.blocks_allocated++;
data_offset = s->header.offset_data +
(uint64_t)bmap_entry * s->block_size;
if (block == NULL) {
block = g_malloc(s->block_size);
bmap_first = block_index;
}
bmap_last = block_index;
/* Copy data to be written to new block and zero unused parts. */
memset(block, 0, offset_in_block);
qemu_iovec_to_buf(qiov, bytes_done, block + offset_in_block,
n_bytes);
memset(block + offset_in_block + n_bytes, 0,
s->block_size - n_bytes - offset_in_block);
/* Write the new block under CoRwLock write-side protection,
* so this full-cluster write does not overlap a partial write
* of the same cluster, issued from the "else" branch.
*/
ret = bdrv_pwrite(bs->file, data_offset, block, s->block_size);
qemu_co_rwlock_unlock(&s->bmap_lock);
} else {
nonallocating_write:
data_offset = s->header.offset_data +
(uint64_t)bmap_entry * s->block_size +
offset_in_block;
qemu_co_rwlock_unlock(&s->bmap_lock);
qemu_iovec_reset(&local_qiov);
qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes);
ret = bdrv_co_pwritev(bs->file, data_offset, n_bytes,
&local_qiov, 0);
}
bytes -= n_bytes;
offset += n_bytes;
bytes_done += n_bytes;
logout("%u bytes written\n", n_bytes);
}
qemu_iovec_destroy(&local_qiov);
logout("finished data write\n");
if (ret < 0) {
g_free(block);
return ret;
}
if (block) {
/* One or more new blocks were allocated. */
VdiHeader *header;
uint8_t *base;
uint64_t offset;
uint32_t n_sectors;
g_free(block);
header = g_malloc(sizeof(*header));
logout("now writing modified header\n");
assert(VDI_IS_ALLOCATED(bmap_first));
*header = s->header;
vdi_header_to_le(header);
ret = bdrv_pwrite(bs->file, 0, header, sizeof(*header));
g_free(header);
if (ret < 0) {
return ret;
}
logout("now writing modified block map entry %u...%u\n",
bmap_first, bmap_last);
/* Write modified sectors from block map. */
bmap_first /= (SECTOR_SIZE / sizeof(uint32_t));
bmap_last /= (SECTOR_SIZE / sizeof(uint32_t));
n_sectors = bmap_last - bmap_first + 1;
offset = s->bmap_sector + bmap_first;
base = ((uint8_t *)&s->bmap[0]) + bmap_first * SECTOR_SIZE;
logout("will write %u block map sectors starting from entry %u\n",
n_sectors, bmap_first);
ret = bdrv_pwrite(bs->file, offset * SECTOR_SIZE, base,
n_sectors * SECTOR_SIZE);
}
return ret < 0 ? ret : 0;
}
static int coroutine_fn vdi_co_do_create(BlockdevCreateOptions *create_options,
size_t block_size, Error **errp)
{
BlockdevCreateOptionsVdi *vdi_opts;
int ret = 0;
uint64_t bytes = 0;
uint32_t blocks;
uint32_t image_type;
VdiHeader header;
size_t i;
size_t bmap_size;
int64_t offset = 0;
BlockDriverState *bs_file = NULL;
BlockBackend *blk = NULL;
uint32_t *bmap = NULL;
QemuUUID uuid;
assert(create_options->driver == BLOCKDEV_DRIVER_VDI);
vdi_opts = &create_options->u.vdi;
logout("\n");
/* Validate options and set default values */
bytes = vdi_opts->size;
if (!vdi_opts->has_preallocation) {
vdi_opts->preallocation = PREALLOC_MODE_OFF;
}
switch (vdi_opts->preallocation) {
case PREALLOC_MODE_OFF:
image_type = VDI_TYPE_DYNAMIC;
break;
case PREALLOC_MODE_METADATA:
image_type = VDI_TYPE_STATIC;
break;
default:
error_setg(errp, "Preallocation mode not supported for vdi");
return -EINVAL;
}
#ifndef CONFIG_VDI_STATIC_IMAGE
if (image_type == VDI_TYPE_STATIC) {
ret = -ENOTSUP;
error_setg(errp, "Statically allocated images cannot be created in "
"this build");
goto exit;
}
#endif
#ifndef CONFIG_VDI_BLOCK_SIZE
if (block_size != DEFAULT_CLUSTER_SIZE) {
ret = -ENOTSUP;
error_setg(errp,
"A non-default cluster size is not supported in this build");
goto exit;
}
#endif
if (bytes > VDI_DISK_SIZE_MAX) {
ret = -ENOTSUP;
error_setg(errp, "Unsupported VDI image size (size is 0x%" PRIx64
", max supported is 0x%" PRIx64 ")",
bytes, VDI_DISK_SIZE_MAX);
goto exit;
}
/* Create BlockBackend to write to the image */
bs_file = bdrv_open_blockdev_ref(vdi_opts->file, errp);
if (!bs_file) {
ret = -EIO;
goto exit;
}
blk = blk_new_with_bs(bs_file, BLK_PERM_WRITE | BLK_PERM_RESIZE,
BLK_PERM_ALL, errp);
if (!blk) {
ret = -EPERM;
goto exit;
}
blk_set_allow_write_beyond_eof(blk, true);
/* We need enough blocks to store the given disk size,
so always round up. */
blocks = DIV_ROUND_UP(bytes, block_size);
bmap_size = blocks * sizeof(uint32_t);
bmap_size = ROUND_UP(bmap_size, SECTOR_SIZE);
memset(&header, 0, sizeof(header));
pstrcpy(header.text, sizeof(header.text), VDI_TEXT);
header.signature = VDI_SIGNATURE;
header.version = VDI_VERSION_1_1;
header.header_size = 0x180;
header.image_type = image_type;
header.offset_bmap = 0x200;
header.offset_data = 0x200 + bmap_size;
header.sector_size = SECTOR_SIZE;
header.disk_size = bytes;
header.block_size = block_size;
header.blocks_in_image = blocks;
if (image_type == VDI_TYPE_STATIC) {
header.blocks_allocated = blocks;
}
qemu_uuid_generate(&uuid);
header.uuid_image = uuid;
qemu_uuid_generate(&uuid);
header.uuid_last_snap = uuid;
/* There is no need to set header.uuid_link or header.uuid_parent here. */
if (VDI_DEBUG) {
vdi_header_print(&header);
}
vdi_header_to_le(&header);
ret = blk_pwrite(blk, offset, &header, sizeof(header), 0);
if (ret < 0) {
error_setg(errp, "Error writing header");
goto exit;
}
offset += sizeof(header);
if (bmap_size > 0) {
bmap = g_try_malloc0(bmap_size);
if (bmap == NULL) {
ret = -ENOMEM;
error_setg(errp, "Could not allocate bmap");
goto exit;
}
for (i = 0; i < blocks; i++) {
if (image_type == VDI_TYPE_STATIC) {
bmap[i] = i;
} else {
bmap[i] = VDI_UNALLOCATED;
}
}
ret = blk_pwrite(blk, offset, bmap, bmap_size, 0);
if (ret < 0) {
error_setg(errp, "Error writing bmap");
goto exit;
}
offset += bmap_size;
}
if (image_type == VDI_TYPE_STATIC) {
ret = blk_truncate(blk, offset + blocks * block_size, false,
PREALLOC_MODE_OFF, 0, errp);
if (ret < 0) {
error_prepend(errp, "Failed to statically allocate file");
goto exit;
}
}
ret = 0;
exit:
blk_unref(blk);
bdrv_unref(bs_file);
g_free(bmap);
return ret;
}
static int coroutine_fn vdi_co_create(BlockdevCreateOptions *create_options,
Error **errp)
{
return vdi_co_do_create(create_options, DEFAULT_CLUSTER_SIZE, errp);
}
static int coroutine_fn vdi_co_create_opts(BlockDriver *drv,
const char *filename,
QemuOpts *opts,
Error **errp)
{
QDict *qdict = NULL;
BlockdevCreateOptions *create_options = NULL;
BlockDriverState *bs_file = NULL;
uint64_t block_size = DEFAULT_CLUSTER_SIZE;
bool is_static = false;
Visitor *v;
int ret;
/* Parse options and convert legacy syntax.
*
* Since CONFIG_VDI_BLOCK_SIZE is disabled by default,
* cluster-size is not part of the QAPI schema; therefore we have
* to parse it before creating the QAPI object. */
#if defined(CONFIG_VDI_BLOCK_SIZE)
block_size = qemu_opt_get_size_del(opts,
BLOCK_OPT_CLUSTER_SIZE,
DEFAULT_CLUSTER_SIZE);
if (block_size < BDRV_SECTOR_SIZE || block_size > UINT32_MAX ||
!is_power_of_2(block_size))
{
error_setg(errp, "Invalid cluster size");
ret = -EINVAL;
goto done;
}
#endif
if (qemu_opt_get_bool_del(opts, BLOCK_OPT_STATIC, false)) {
is_static = true;
}
qdict = qemu_opts_to_qdict_filtered(opts, NULL, &vdi_create_opts, true);
/* Create and open the file (protocol layer) */
ret = bdrv_create_file(filename, opts, errp);
if (ret < 0) {
goto done;
}
bs_file = bdrv_open(filename, NULL, NULL,
BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
if (!bs_file) {
ret = -EIO;
goto done;
}
qdict_put_str(qdict, "driver", "vdi");
qdict_put_str(qdict, "file", bs_file->node_name);
if (is_static) {
qdict_put_str(qdict, "preallocation", "metadata");
}
/* Get the QAPI object */
v = qobject_input_visitor_new_flat_confused(qdict, errp);
if (!v) {
ret = -EINVAL;
goto done;
}
visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
visit_free(v);
if (!create_options) {
ret = -EINVAL;
goto done;
}
/* Silently round up size */
assert(create_options->driver == BLOCKDEV_DRIVER_VDI);
create_options->u.vdi.size = ROUND_UP(create_options->u.vdi.size,
BDRV_SECTOR_SIZE);
/* Create the vdi image (format layer) */
ret = vdi_co_do_create(create_options, block_size, errp);
done:
qobject_unref(qdict);
qapi_free_BlockdevCreateOptions(create_options);
bdrv_unref(bs_file);
return ret;
}
static void vdi_close(BlockDriverState *bs)
{
BDRVVdiState *s = bs->opaque;
qemu_vfree(s->bmap);
migrate_del_blocker(s->migration_blocker);
error_free(s->migration_blocker);
}
static int vdi_has_zero_init(BlockDriverState *bs)
{
BDRVVdiState *s = bs->opaque;
if (s->header.image_type == VDI_TYPE_STATIC) {
return bdrv_has_zero_init(bs->file->bs);
} else {
return 1;
}
}
static QemuOptsList vdi_create_opts = {
.name = "vdi-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(vdi_create_opts.head),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size"
},
#if defined(CONFIG_VDI_BLOCK_SIZE)
{
.name = BLOCK_OPT_CLUSTER_SIZE,
.type = QEMU_OPT_SIZE,
.help = "VDI cluster (block) size",
.def_value_str = stringify(DEFAULT_CLUSTER_SIZE)
},
#endif
#if defined(CONFIG_VDI_STATIC_IMAGE)
{
.name = BLOCK_OPT_STATIC,
.type = QEMU_OPT_BOOL,
.help = "VDI static (pre-allocated) image",
.def_value_str = "off"
},
#endif
/* TODO: An additional option to set UUID values might be useful. */
{ /* end of list */ }
}
};
static BlockDriver bdrv_vdi = {
.format_name = "vdi",
.instance_size = sizeof(BDRVVdiState),
.bdrv_probe = vdi_probe,
.bdrv_open = vdi_open,
.bdrv_close = vdi_close,
.bdrv_reopen_prepare = vdi_reopen_prepare,
.bdrv_child_perm = bdrv_default_perms,
.bdrv_co_create = vdi_co_create,
.bdrv_co_create_opts = vdi_co_create_opts,
.bdrv_has_zero_init = vdi_has_zero_init,
.bdrv_co_block_status = vdi_co_block_status,
.bdrv_make_empty = vdi_make_empty,
.bdrv_co_preadv = vdi_co_preadv,
#if defined(CONFIG_VDI_WRITE)
.bdrv_co_pwritev = vdi_co_pwritev,
#endif
.bdrv_get_info = vdi_get_info,
.is_format = true,
.create_opts = &vdi_create_opts,
.bdrv_co_check = vdi_co_check,
};
static void bdrv_vdi_init(void)
{
logout("\n");
bdrv_register(&bdrv_vdi);
}
block_init(bdrv_vdi_init);
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