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xemu/block/vdi.c
Max Reitz c80d8b06cf block: Add @exact parameter to bdrv_co_truncate() 
We have two drivers (iscsi and file-posix) that (in some cases) return
success from their .bdrv_co_truncate() implementation if the block
device is larger than the requested offset, but cannot be shrunk.  Some
callers do not want that behavior, so this patch adds a new parameter
that they can use to turn off that behavior.

This patch just adds the parameter and lets the block/io.c and
block/block-backend.c functions pass it around.  All other callers
always pass false and none of the implementations evaluate it, so that
this patch does not change existing behavior.  Future patches take care
of that.

Suggested-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190918095144.955-5-mreitz@redhat.com
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-28 12:00:07 +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;
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;
Error *local_err = NULL;
QemuUUID uuid_link, uuid_parent;
bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
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, &local_err);
if (local_err) {
error_propagate(errp, local_err);
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 0;
}
*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) {
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_pwrite(bs->file, 0, block, sizeof(VdiHeader));
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_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(bdrv_get_aio_context(bs_file),
BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
ret = blk_insert_bs(blk, bs_file, errp);
if (ret < 0) {
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, 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(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;
Error *local_err = NULL;
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, &local_err);
visit_free(v);
if (local_err) {
error_propagate(errp, local_err);
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_format_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,
.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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