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qemu/block/vdi.c
Kevin Wolf e67a64a869 vdi: Avoid direct AIO callback 
bdrv_aio_* must not call the callback before returning to its caller. In vdi,
this could happen in some error cases. This starts the real requests processing
in a BH to avoid this situation.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-06-15 14:35:15 +02:00

1000 lines
30 KiB
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/*
* Block driver for the Virtual Disk Image (VDI) format
*
* Copyright (c) 2009 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 adjacents 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-common.h"
#include "block_int.h"
#include "module.h"
#if defined(CONFIG_UUID)
#include <uuid/uuid.h>
#else
/* TODO: move uuid emulation to some central place in QEMU. */
#include "sysemu.h" /* UUID_FMT */
typedef unsigned char uuid_t[16];
void uuid_generate(uuid_t out);
int uuid_is_null(const uuid_t uu);
void uuid_unparse(const uuid_t uu, char *out);
#endif
/* 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 KiB 1024
#define MiB (KiB * KiB)
#define SECTOR_SIZE 512
#define DEFAULT_CLUSTER_SIZE (1 * MiB)
#if defined(CONFIG_VDI_DEBUG)
#define logout(fmt, ...) \
fprintf(stderr, "vdi\t%-24s" fmt, __func__, ##__VA_ARGS__)
#else
#define logout(fmt, ...) ((void)0)
#endif
/* 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"
/* Unallocated blocks use this index (no need to convert endianness). */
#define VDI_UNALLOCATED UINT32_MAX
#if !defined(CONFIG_UUID)
void uuid_generate(uuid_t out)
{
memset(out, 0, sizeof(uuid_t));
}
int uuid_is_null(const uuid_t uu)
{
uuid_t null_uuid = { 0 };
return memcmp(uu, null_uuid, sizeof(uuid_t)) == 0;
}
void uuid_unparse(const uuid_t uu, char *out)
{
snprintf(out, 37, UUID_FMT,
uu[0], uu[1], uu[2], uu[3], uu[4], uu[5], uu[6], uu[7],
uu[8], uu[9], uu[10], uu[11], uu[12], uu[13], uu[14], uu[15]);
}
#endif
typedef struct {
BlockDriverAIOCB common;
int64_t sector_num;
QEMUIOVector *qiov;
uint8_t *buf;
/* Total number of sectors. */
int nb_sectors;
/* Number of sectors for current AIO. */
int n_sectors;
/* New allocated block map entry. */
uint32_t bmap_first;
uint32_t bmap_last;
/* Buffer for new allocated block. */
void *block_buffer;
void *orig_buf;
bool is_write;
int header_modified;
BlockDriverAIOCB *hd_aiocb;
struct iovec hd_iov;
QEMUIOVector hd_qiov;
QEMUBH *bh;
} VdiAIOCB;
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;
uuid_t uuid_image;
uuid_t uuid_last_snap;
uuid_t uuid_link;
uuid_t uuid_parent;
uint64_t unused2[7];
} VdiHeader;
typedef struct {
/* The block map entries are little endian (even in memory). */
uint32_t *bmap;
/* Size of block (bytes). */
uint32_t block_size;
/* Size of block (sectors). */
uint32_t block_sectors;
/* First sector of block map. */
uint32_t bmap_sector;
/* VDI header (converted to host endianness). */
VdiHeader header;
} BDRVVdiState;
/* Change UUID from little endian (IPRT = VirtualBox format) to big endian
* format (network byte order, standard, see RFC 4122) and vice versa.
*/
static void uuid_convert(uuid_t uuid)
{
bswap32s((uint32_t *)&uuid[0]);
bswap16s((uint16_t *)&uuid[4]);
bswap16s((uint16_t *)&uuid[6]);
}
static void vdi_header_to_cpu(VdiHeader *header)
{
le32_to_cpus(&header->signature);
le32_to_cpus(&header->version);
le32_to_cpus(&header->header_size);
le32_to_cpus(&header->image_type);
le32_to_cpus(&header->image_flags);
le32_to_cpus(&header->offset_bmap);
le32_to_cpus(&header->offset_data);
le32_to_cpus(&header->cylinders);
le32_to_cpus(&header->heads);
le32_to_cpus(&header->sectors);
le32_to_cpus(&header->sector_size);
le64_to_cpus(&header->disk_size);
le32_to_cpus(&header->block_size);
le32_to_cpus(&header->block_extra);
le32_to_cpus(&header->blocks_in_image);
le32_to_cpus(&header->blocks_allocated);
uuid_convert(header->uuid_image);
uuid_convert(header->uuid_last_snap);
uuid_convert(header->uuid_link);
uuid_convert(header->uuid_parent);
}
static void vdi_header_to_le(VdiHeader *header)
{
cpu_to_le32s(&header->signature);
cpu_to_le32s(&header->version);
cpu_to_le32s(&header->header_size);
cpu_to_le32s(&header->image_type);
cpu_to_le32s(&header->image_flags);
cpu_to_le32s(&header->offset_bmap);
cpu_to_le32s(&header->offset_data);
cpu_to_le32s(&header->cylinders);
cpu_to_le32s(&header->heads);
cpu_to_le32s(&header->sectors);
cpu_to_le32s(&header->sector_size);
cpu_to_le64s(&header->disk_size);
cpu_to_le32s(&header->block_size);
cpu_to_le32s(&header->block_extra);
cpu_to_le32s(&header->blocks_in_image);
cpu_to_le32s(&header->blocks_allocated);
cpu_to_le32s(&header->blocks_allocated);
uuid_convert(header->uuid_image);
uuid_convert(header->uuid_last_snap);
uuid_convert(header->uuid_link);
uuid_convert(header->uuid_parent);
}
#if defined(CONFIG_VDI_DEBUG)
static void vdi_header_print(VdiHeader *header)
{
char uuid[37];
logout("text %s", header->text);
logout("signature 0x%04x\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_unparse(header->uuid_image, uuid);
logout("uuid image %s\n", uuid);
uuid_unparse(header->uuid_last_snap, uuid);
logout("uuid snap %s\n", uuid);
uuid_unparse(header->uuid_link, uuid);
logout("uuid link %s\n", uuid);
uuid_unparse(header->uuid_parent, uuid);
logout("uuid parent %s\n", uuid);
}
#endif
static int vdi_check(BlockDriverState *bs, BdrvCheckResult *res)
{
/* TODO: additional checks possible. */
BDRVVdiState *s = (BDRVVdiState *)bs->opaque;
uint32_t blocks_allocated = 0;
uint32_t block;
uint32_t *bmap;
logout("\n");
bmap = qemu_malloc(s->header.blocks_in_image * sizeof(uint32_t));
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 (bmap_entry != VDI_UNALLOCATED) {
if (bmap_entry < s->header.blocks_in_image) {
blocks_allocated++;
if (bmap[bmap_entry] == VDI_UNALLOCATED) {
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++;
}
qemu_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 result = 0;
logout("\n");
if (buf_size < sizeof(*header)) {
/* Header too small, no VDI. */
} else if (le32_to_cpu(header->signature) == VDI_SIGNATURE) {
result = 100;
}
if (result == 0) {
logout("no vdi image\n");
} else {
logout("%s", header->text);
}
return result;
}
static int vdi_open(BlockDriverState *bs, int flags)
{
BDRVVdiState *s = bs->opaque;
VdiHeader header;
size_t bmap_size;
logout("\n");
if (bdrv_read(bs->file, 0, (uint8_t *)&header, 1) < 0) {
goto fail;
}
vdi_header_to_cpu(&header);
#if defined(CONFIG_VDI_DEBUG)
vdi_header_print(&header);
#endif
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 += SECTOR_SIZE - 1;
header.disk_size &= ~(SECTOR_SIZE - 1);
}
if (header.version != VDI_VERSION_1_1) {
logout("unsupported version %u.%u\n",
header.version >> 16, header.version & 0xffff);
goto fail;
} else if (header.offset_bmap % SECTOR_SIZE != 0) {
/* We only support block maps which start on a sector boundary. */
logout("unsupported block map offset 0x%x B\n", header.offset_bmap);
goto fail;
} else if (header.offset_data % SECTOR_SIZE != 0) {
/* We only support data blocks which start on a sector boundary. */
logout("unsupported data offset 0x%x B\n", header.offset_data);
goto fail;
} else if (header.sector_size != SECTOR_SIZE) {
logout("unsupported sector size %u B\n", header.sector_size);
goto fail;
} else if (header.block_size != 1 * MiB) {
logout("unsupported block size %u B\n", header.block_size);
goto fail;
} else if (header.disk_size >
(uint64_t)header.blocks_in_image * header.block_size) {
logout("unsupported disk size %" PRIu64 " B\n", header.disk_size);
goto fail;
} else if (!uuid_is_null(header.uuid_link)) {
logout("link uuid != 0, unsupported\n");
goto fail;
} else if (!uuid_is_null(header.uuid_parent)) {
logout("parent uuid != 0, unsupported\n");
goto fail;
}
bs->total_sectors = header.disk_size / SECTOR_SIZE;
s->block_size = header.block_size;
s->block_sectors = header.block_size / SECTOR_SIZE;
s->bmap_sector = header.offset_bmap / SECTOR_SIZE;
s->header = header;
bmap_size = header.blocks_in_image * sizeof(uint32_t);
bmap_size = (bmap_size + SECTOR_SIZE - 1) / SECTOR_SIZE;
if (bmap_size > 0) {
s->bmap = qemu_malloc(bmap_size * SECTOR_SIZE);
}
if (bdrv_read(bs->file, s->bmap_sector, (uint8_t *)s->bmap, bmap_size) < 0) {
goto fail_free_bmap;
}
return 0;
fail_free_bmap:
qemu_free(s->bmap);
fail:
return -1;
}
static int vdi_is_allocated(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int *pnum)
{
/* TODO: Check for too large sector_num (in bdrv_is_allocated or here). */
BDRVVdiState *s = (BDRVVdiState *)bs->opaque;
size_t bmap_index = sector_num / s->block_sectors;
size_t sector_in_block = sector_num % s->block_sectors;
int n_sectors = s->block_sectors - sector_in_block;
uint32_t bmap_entry = le32_to_cpu(s->bmap[bmap_index]);
logout("%p, %" PRId64 ", %d, %p\n", bs, sector_num, nb_sectors, pnum);
if (n_sectors > nb_sectors) {
n_sectors = nb_sectors;
}
*pnum = n_sectors;
return bmap_entry != VDI_UNALLOCATED;
}
static void vdi_aio_cancel(BlockDriverAIOCB *blockacb)
{
/* TODO: This code is untested. How can I get it executed? */
VdiAIOCB *acb = container_of(blockacb, VdiAIOCB, common);
logout("\n");
if (acb->hd_aiocb) {
bdrv_aio_cancel(acb->hd_aiocb);
}
qemu_aio_release(acb);
}
static AIOPool vdi_aio_pool = {
.aiocb_size = sizeof(VdiAIOCB),
.cancel = vdi_aio_cancel,
};
static VdiAIOCB *vdi_aio_setup(BlockDriverState *bs, int64_t sector_num,
QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque, int is_write)
{
VdiAIOCB *acb;
logout("%p, %" PRId64 ", %p, %d, %p, %p, %d\n",
bs, sector_num, qiov, nb_sectors, cb, opaque, is_write);
acb = qemu_aio_get(&vdi_aio_pool, bs, cb, opaque);
if (acb) {
acb->hd_aiocb = NULL;
acb->sector_num = sector_num;
acb->qiov = qiov;
acb->is_write = is_write;
if (qiov->niov > 1) {
acb->buf = qemu_blockalign(bs, qiov->size);
acb->orig_buf = acb->buf;
if (is_write) {
qemu_iovec_to_buffer(qiov, acb->buf);
}
} else {
acb->buf = (uint8_t *)qiov->iov->iov_base;
}
acb->nb_sectors = nb_sectors;
acb->n_sectors = 0;
acb->bmap_first = VDI_UNALLOCATED;
acb->bmap_last = VDI_UNALLOCATED;
acb->block_buffer = NULL;
acb->header_modified = 0;
}
return acb;
}
static int vdi_schedule_bh(QEMUBHFunc *cb, VdiAIOCB *acb)
{
logout("\n");
if (acb->bh) {
return -EIO;
}
acb->bh = qemu_bh_new(cb, acb);
if (!acb->bh) {
return -EIO;
}
qemu_bh_schedule(acb->bh);
return 0;
}
static void vdi_aio_read_cb(void *opaque, int ret);
static void vdi_aio_write_cb(void *opaque, int ret);
static void vdi_aio_rw_bh(void *opaque)
{
VdiAIOCB *acb = opaque;
logout("\n");
qemu_bh_delete(acb->bh);
acb->bh = NULL;
if (acb->is_write) {
vdi_aio_write_cb(opaque, 0);
} else {
vdi_aio_read_cb(opaque, 0);
}
}
static void vdi_aio_read_cb(void *opaque, int ret)
{
VdiAIOCB *acb = opaque;
BlockDriverState *bs = acb->common.bs;
BDRVVdiState *s = bs->opaque;
uint32_t bmap_entry;
uint32_t block_index;
uint32_t sector_in_block;
uint32_t n_sectors;
logout("%u sectors read\n", acb->n_sectors);
acb->hd_aiocb = NULL;
if (ret < 0) {
goto done;
}
acb->nb_sectors -= acb->n_sectors;
if (acb->nb_sectors == 0) {
/* request completed */
ret = 0;
goto done;
}
acb->sector_num += acb->n_sectors;
acb->buf += acb->n_sectors * SECTOR_SIZE;
block_index = acb->sector_num / s->block_sectors;
sector_in_block = acb->sector_num % s->block_sectors;
n_sectors = s->block_sectors - sector_in_block;
if (n_sectors > acb->nb_sectors) {
n_sectors = acb->nb_sectors;
}
logout("will read %u sectors starting at sector %" PRIu64 "\n",
n_sectors, acb->sector_num);
/* prepare next AIO request */
acb->n_sectors = n_sectors;
bmap_entry = le32_to_cpu(s->bmap[block_index]);
if (bmap_entry == VDI_UNALLOCATED) {
/* Block not allocated, return zeros, no need to wait. */
memset(acb->buf, 0, n_sectors * SECTOR_SIZE);
ret = vdi_schedule_bh(vdi_aio_rw_bh, acb);
if (ret < 0) {
goto done;
}
} else {
uint64_t offset = s->header.offset_data / SECTOR_SIZE +
(uint64_t)bmap_entry * s->block_sectors +
sector_in_block;
acb->hd_iov.iov_base = (void *)acb->buf;
acb->hd_iov.iov_len = n_sectors * SECTOR_SIZE;
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
acb->hd_aiocb = bdrv_aio_readv(bs->file, offset, &acb->hd_qiov,
n_sectors, vdi_aio_read_cb, acb);
if (acb->hd_aiocb == NULL) {
ret = -EIO;
goto done;
}
}
return;
done:
if (acb->qiov->niov > 1) {
qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size);
qemu_vfree(acb->orig_buf);
}
acb->common.cb(acb->common.opaque, ret);
qemu_aio_release(acb);
}
static BlockDriverAIOCB *vdi_aio_readv(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque)
{
VdiAIOCB *acb;
int ret;
logout("\n");
acb = vdi_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
if (!acb) {
return NULL;
}
ret = vdi_schedule_bh(vdi_aio_rw_bh, acb);
if (ret < 0) {
if (acb->qiov->niov > 1) {
qemu_vfree(acb->orig_buf);
}
qemu_aio_release(acb);
return NULL;
}
return &acb->common;
}
static void vdi_aio_write_cb(void *opaque, int ret)
{
VdiAIOCB *acb = opaque;
BlockDriverState *bs = acb->common.bs;
BDRVVdiState *s = bs->opaque;
uint32_t bmap_entry;
uint32_t block_index;
uint32_t sector_in_block;
uint32_t n_sectors;
acb->hd_aiocb = NULL;
if (ret < 0) {
goto done;
}
acb->nb_sectors -= acb->n_sectors;
acb->sector_num += acb->n_sectors;
acb->buf += acb->n_sectors * SECTOR_SIZE;
if (acb->nb_sectors == 0) {
logout("finished data write\n");
acb->n_sectors = 0;
if (acb->header_modified) {
VdiHeader *header = acb->block_buffer;
logout("now writing modified header\n");
assert(acb->bmap_first != VDI_UNALLOCATED);
*header = s->header;
vdi_header_to_le(header);
acb->header_modified = 0;
acb->hd_iov.iov_base = acb->block_buffer;
acb->hd_iov.iov_len = SECTOR_SIZE;
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
acb->hd_aiocb = bdrv_aio_writev(bs->file, 0, &acb->hd_qiov, 1,
vdi_aio_write_cb, acb);
if (acb->hd_aiocb == NULL) {
ret = -EIO;
goto done;
}
return;
} else if (acb->bmap_first != VDI_UNALLOCATED) {
/* One or more new blocks were allocated. */
uint64_t offset;
uint32_t bmap_first;
uint32_t bmap_last;
qemu_free(acb->block_buffer);
acb->block_buffer = NULL;
bmap_first = acb->bmap_first;
bmap_last = acb->bmap_last;
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;
acb->bmap_first = VDI_UNALLOCATED;
acb->hd_iov.iov_base = (void *)((uint8_t *)&s->bmap[0] +
bmap_first * SECTOR_SIZE);
acb->hd_iov.iov_len = n_sectors * SECTOR_SIZE;
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
logout("will write %u block map sectors starting from entry %u\n",
n_sectors, bmap_first);
acb->hd_aiocb = bdrv_aio_writev(bs->file, offset, &acb->hd_qiov,
n_sectors, vdi_aio_write_cb, acb);
if (acb->hd_aiocb == NULL) {
ret = -EIO;
goto done;
}
return;
}
ret = 0;
goto done;
}
logout("%u sectors written\n", acb->n_sectors);
block_index = acb->sector_num / s->block_sectors;
sector_in_block = acb->sector_num % s->block_sectors;
n_sectors = s->block_sectors - sector_in_block;
if (n_sectors > acb->nb_sectors) {
n_sectors = acb->nb_sectors;
}
logout("will write %u sectors starting at sector %" PRIu64 "\n",
n_sectors, acb->sector_num);
/* prepare next AIO request */
acb->n_sectors = n_sectors;
bmap_entry = le32_to_cpu(s->bmap[block_index]);
if (bmap_entry == VDI_UNALLOCATED) {
/* Allocate new block and write to it. */
uint64_t offset;
uint8_t *block;
bmap_entry = s->header.blocks_allocated;
s->bmap[block_index] = cpu_to_le32(bmap_entry);
s->header.blocks_allocated++;
offset = s->header.offset_data / SECTOR_SIZE +
(uint64_t)bmap_entry * s->block_sectors;
block = acb->block_buffer;
if (block == NULL) {
block = qemu_mallocz(s->block_size);
acb->block_buffer = block;
acb->bmap_first = block_index;
assert(!acb->header_modified);
acb->header_modified = 1;
}
acb->bmap_last = block_index;
memcpy(block + sector_in_block * SECTOR_SIZE,
acb->buf, n_sectors * SECTOR_SIZE);
acb->hd_iov.iov_base = (void *)block;
acb->hd_iov.iov_len = s->block_size;
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
acb->hd_aiocb = bdrv_aio_writev(bs->file, offset,
&acb->hd_qiov, s->block_sectors,
vdi_aio_write_cb, acb);
if (acb->hd_aiocb == NULL) {
ret = -EIO;
goto done;
}
} else {
uint64_t offset = s->header.offset_data / SECTOR_SIZE +
(uint64_t)bmap_entry * s->block_sectors +
sector_in_block;
acb->hd_iov.iov_base = (void *)acb->buf;
acb->hd_iov.iov_len = n_sectors * SECTOR_SIZE;
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
acb->hd_aiocb = bdrv_aio_writev(bs->file, offset, &acb->hd_qiov,
n_sectors, vdi_aio_write_cb, acb);
if (acb->hd_aiocb == NULL) {
ret = -EIO;
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 *vdi_aio_writev(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque)
{
VdiAIOCB *acb;
int ret;
logout("\n");
acb = vdi_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
if (!acb) {
return NULL;
}
ret = vdi_schedule_bh(vdi_aio_rw_bh, acb);
if (ret < 0) {
if (acb->qiov->niov > 1) {
qemu_vfree(acb->orig_buf);
}
qemu_aio_release(acb);
return NULL;
}
return &acb->common;
}
static int vdi_create(const char *filename, QEMUOptionParameter *options)
{
int fd;
int result = 0;
uint64_t bytes = 0;
uint32_t blocks;
size_t block_size = DEFAULT_CLUSTER_SIZE;
uint32_t image_type = VDI_TYPE_DYNAMIC;
VdiHeader header;
size_t i;
size_t bmap_size;
uint32_t *bmap;
logout("\n");
/* Read out options. */
while (options && options->name) {
if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
bytes = options->value.n;
#if defined(CONFIG_VDI_BLOCK_SIZE)
} else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
if (options->value.n) {
/* TODO: Additional checks (SECTOR_SIZE * 2^n, ...). */
block_size = options->value.n;
}
#endif
#if defined(CONFIG_VDI_STATIC_IMAGE)
} else if (!strcmp(options->name, BLOCK_OPT_STATIC)) {
if (options->value.n) {
image_type = VDI_TYPE_STATIC;
}
#endif
}
options++;
}
fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
0644);
if (fd < 0) {
return -errno;
}
/* We need enough blocks to store the given disk size,
so always round up. */
blocks = (bytes + block_size - 1) / block_size;
bmap_size = blocks * sizeof(uint32_t);
bmap_size = ((bmap_size + SECTOR_SIZE - 1) & ~(SECTOR_SIZE -1));
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;
}
uuid_generate(header.uuid_image);
uuid_generate(header.uuid_last_snap);
/* There is no need to set header.uuid_link or header.uuid_parent here. */
#if defined(CONFIG_VDI_DEBUG)
vdi_header_print(&header);
#endif
vdi_header_to_le(&header);
if (write(fd, &header, sizeof(header)) < 0) {
result = -errno;
}
bmap = NULL;
if (bmap_size > 0) {
bmap = (uint32_t *)qemu_mallocz(bmap_size);
}
for (i = 0; i < blocks; i++) {
if (image_type == VDI_TYPE_STATIC) {
bmap[i] = i;
} else {
bmap[i] = VDI_UNALLOCATED;
}
}
if (write(fd, bmap, bmap_size) < 0) {
result = -errno;
}
qemu_free(bmap);
if (image_type == VDI_TYPE_STATIC) {
if (ftruncate(fd, sizeof(header) + bmap_size + blocks * block_size)) {
result = -errno;
}
}
if (close(fd) < 0) {
result = -errno;
}
return result;
}
static void vdi_close(BlockDriverState *bs)
{
}
static int vdi_flush(BlockDriverState *bs)
{
logout("\n");
return bdrv_flush(bs->file);
}
static QEMUOptionParameter vdi_create_options[] = {
{
.name = BLOCK_OPT_SIZE,
.type = OPT_SIZE,
.help = "Virtual disk size"
},
#if defined(CONFIG_VDI_BLOCK_SIZE)
{
.name = BLOCK_OPT_CLUSTER_SIZE,
.type = OPT_SIZE,
.help = "VDI cluster (block) size",
.value = { .n = DEFAULT_CLUSTER_SIZE },
},
#endif
#if defined(CONFIG_VDI_STATIC_IMAGE)
{
.name = BLOCK_OPT_STATIC,
.type = OPT_FLAG,
.help = "VDI static (pre-allocated) image"
},
#endif
/* TODO: An additional option to set UUID values might be useful. */
{ NULL }
};
static BlockDriver bdrv_vdi = {
.format_name = "vdi",
.instance_size = sizeof(BDRVVdiState),
.bdrv_probe = vdi_probe,
.bdrv_open = vdi_open,
.bdrv_close = vdi_close,
.bdrv_create = vdi_create,
.bdrv_flush = vdi_flush,
.bdrv_is_allocated = vdi_is_allocated,
.bdrv_make_empty = vdi_make_empty,
.bdrv_aio_readv = vdi_aio_readv,
#if defined(CONFIG_VDI_WRITE)
.bdrv_aio_writev = vdi_aio_writev,
#endif
.bdrv_get_info = vdi_get_info,
.create_options = vdi_create_options,
.bdrv_check = vdi_check,
};
static void bdrv_vdi_init(void)
{
logout("\n");
bdrv_register(&bdrv_vdi);
}
block_init(bdrv_vdi_init);
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