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qemu-e2k/block/vdi.c
Kevin Wolf a03ef88f77 block: Convert bdrv_co_preadv/pwritev to BdrvChild 
This is the final patch for converting the common I/O path to take
a BdrvChild parameter instead of BlockDriverState.

The completion of this conversion means that all users that perform I/O
on an image need to actually hold a reference (in the form of BdrvChild,
possible as part of a BlockBackend) to that image. This also protects
against inconsistent use of BlockBackend vs. BlockDriverState functions
because direct use of a BlockDriverState isn't possible any more and
blk->root is private for block-backends.c.

In addition, we can now distinguish different users in the I/O path,
and the future op blockers work is going to add assertions based on
permissions stored in BdrvChild.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05 16:46:27 +02:00

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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 "qapi/error.h"
#include "block/block_int.h"
#include "sysemu/block-backend.h"
#include "qemu/module.h"
#include "qemu/bswap.h"
#include "migration/migration.h"
#include "qemu/coroutine.h"
#include "qemu/cutils.h"
#if defined(CONFIG_UUID)
#include <uuid/uuid.h>
#else
/* TODO: move uuid emulation to some central place in QEMU. */
#include "sysemu/sysemu.h" /* UUID_FMT */
typedef unsigned char uuid_t[16];
#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"
/* 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)
#if !defined(CONFIG_UUID)
static inline void uuid_generate(uuid_t out)
{
memset(out, 0, sizeof(uuid_t));
}
static inline int uuid_is_null(const uuid_t uu)
{
uuid_t null_uuid = { 0 };
return memcmp(uu, null_uuid, sizeof(uuid_t)) == 0;
}
# if defined(CONFIG_VDI_DEBUG)
static inline 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
#endif
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];
} QEMU_PACKED 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;
CoMutex write_lock;
Error *migration_blocker;
} 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);
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%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_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,
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;
bdi->unallocated_blocks_are_zero = true;
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;
logout("\n");
ret = bdrv_read(bs->file, 0, (uint8_t *)&header, 1);
if (ret < 0) {
goto fail;
}
vdi_header_to_cpu(&header);
#if defined(CONFIG_VDI_DEBUG)
vdi_header_print(&header);
#endif
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;
}
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 %u)", 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 (!uuid_is_null(header.uuid_link)) {
error_setg(errp, "unsupported VDI image (non-NULL link UUID)");
ret = -ENOTSUP;
goto fail;
} else if (!uuid_is_null(header.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->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 = 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_read(bs->file, s->bmap_sector, (uint8_t *)s->bmap,
bmap_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));
migrate_add_blocker(s->migration_blocker);
qemu_co_mutex_init(&s->write_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 int64_t coroutine_fn vdi_co_get_block_status(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file)
{
/* 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]);
uint64_t offset;
int result;
logout("%p, %" PRId64 ", %d, %p\n", bs, sector_num, nb_sectors, pnum);
if (n_sectors > nb_sectors) {
n_sectors = nb_sectors;
}
*pnum = n_sectors;
result = VDI_IS_ALLOCATED(bmap_entry);
if (!result) {
return 0;
}
offset = s->header.offset_data +
(uint64_t)bmap_entry * s->block_size +
sector_in_block * SECTOR_SIZE;
*file = bs->file->bs;
return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | offset;
}
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 */
bmap_entry = le32_to_cpu(s->bmap[block_index]);
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;
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 */
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;
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);
/* Note that this coroutine does not yield anywhere from reading the
* bmap entry until here, so in regards to all the coroutines trying
* to write to this cluster, the one doing the allocation will
* always be the first to try to acquire the lock.
* Therefore, it is also the first that will actually be able to
* acquire the lock and thus the padded cluster is written before
* the other coroutines can write to the affected area. */
qemu_co_mutex_lock(&s->write_lock);
ret = bdrv_pwrite(bs->file, data_offset, block, s->block_size);
qemu_co_mutex_unlock(&s->write_lock);
} else {
uint64_t data_offset = s->header.offset_data +
(uint64_t)bmap_entry * s->block_size +
offset_in_block;
qemu_co_mutex_lock(&s->write_lock);
/* This lock is only used to make sure the following write operation
* is executed after the write issued by the coroutine allocating
* this cluster, therefore we do not need to keep it locked.
* As stated above, the allocating coroutine will always try to lock
* the mutex before all the other concurrent accesses to that
* cluster, therefore at this point we can be absolutely certain
* that that write operation has returned (there may be other writes
* in flight, but they do not concern this very operation). */
qemu_co_mutex_unlock(&s->write_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) {
return ret;
}
if (block) {
/* One or more new blocks were allocated. */
VdiHeader *header = (VdiHeader *) block;
uint8_t *base;
uint64_t offset;
uint32_t n_sectors;
logout("now writing modified header\n");
assert(VDI_IS_ALLOCATED(bmap_first));
*header = s->header;
vdi_header_to_le(header);
ret = bdrv_write(bs->file, 0, block, 1);
g_free(block);
block = NULL;
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_write(bs->file, offset, base, n_sectors);
}
return ret;
}
static int vdi_create(const char *filename, QemuOpts *opts, Error **errp)
{
int ret = 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;
int64_t offset = 0;
Error *local_err = NULL;
BlockBackend *blk = NULL;
uint32_t *bmap = NULL;
logout("\n");
/* Read out options. */
bytes = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
BDRV_SECTOR_SIZE);
#if defined(CONFIG_VDI_BLOCK_SIZE)
/* TODO: Additional checks (SECTOR_SIZE * 2^n, ...). */
block_size = qemu_opt_get_size_del(opts,
BLOCK_OPT_CLUSTER_SIZE,
DEFAULT_CLUSTER_SIZE);
#endif
#if defined(CONFIG_VDI_STATIC_IMAGE)
if (qemu_opt_get_bool_del(opts, BLOCK_OPT_STATIC, false)) {
image_type = VDI_TYPE_STATIC;
}
#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;
}
ret = bdrv_create_file(filename, opts, &local_err);
if (ret < 0) {
error_propagate(errp, local_err);
goto exit;
}
blk = blk_new_open(filename, NULL, NULL,
BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
if (blk == NULL) {
error_propagate(errp, local_err);
ret = -EIO;
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;
}
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);
ret = blk_pwrite(blk, offset, &header, sizeof(header), 0);
if (ret < 0) {
error_setg(errp, "Error writing header to %s", filename);
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 to %s", filename);
goto exit;
}
offset += bmap_size;
}
if (image_type == VDI_TYPE_STATIC) {
ret = blk_truncate(blk, offset + blocks * block_size);
if (ret < 0) {
error_setg(errp, "Failed to statically allocate %s", filename);
goto exit;
}
}
exit:
blk_unref(blk);
g_free(bmap);
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 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_create = vdi_create,
.bdrv_has_zero_init = bdrv_has_zero_init_1,
.bdrv_co_get_block_status = vdi_co_get_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,
.create_opts = &vdi_create_opts,
.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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