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qemu/block/vpc.c
Kevin Wolf 72e775c7d9 block: Always set writeback mode in blk_new_open() 
All callers of blk_new_open() either don't rely on the WCE bit set after
blk_new_open() because they explicitly set it anyway, or they pass
BDRV_O_CACHE_WB unconditionally.

This patch changes blk_new_open() so that it always enables writeback
mode and asserts that BDRV_O_CACHE_WB is clear. For those callers that
used to pass BDRV_O_CACHE_WB unconditionally, the flag is removed now.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-03-30 12:16:01 +02:00

1061 lines
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/*
* Block driver for Connectix / Microsoft Virtual PC images
*
* Copyright (c) 2005 Alex Beregszaszi
* Copyright (c) 2009 Kevin Wolf <kwolf@suse.de>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu-common.h"
#include "block/block_int.h"
#include "sysemu/block-backend.h"
#include "qemu/module.h"
#include "migration/migration.h"
#if defined(CONFIG_UUID)
#include <uuid/uuid.h>
#endif
/**************************************************************/
#define HEADER_SIZE 512
//#define CACHE
enum vhd_type {
VHD_FIXED = 2,
VHD_DYNAMIC = 3,
VHD_DIFFERENCING = 4,
};
// Seconds since Jan 1, 2000 0:00:00 (UTC)
#define VHD_TIMESTAMP_BASE 946684800
#define VHD_CHS_MAX_C 65535LL
#define VHD_CHS_MAX_H 16
#define VHD_CHS_MAX_S 255
#define VHD_MAX_SECTORS (65535LL * 255 * 255)
#define VHD_MAX_GEOMETRY (VHD_CHS_MAX_C * VHD_CHS_MAX_H * VHD_CHS_MAX_S)
#define VPC_OPT_FORCE_SIZE "force_size"
// always big-endian
typedef struct vhd_footer {
char creator[8]; // "conectix"
uint32_t features;
uint32_t version;
// Offset of next header structure, 0xFFFFFFFF if none
uint64_t data_offset;
// Seconds since Jan 1, 2000 0:00:00 (UTC)
uint32_t timestamp;
char creator_app[4]; // "vpc "
uint16_t major;
uint16_t minor;
char creator_os[4]; // "Wi2k"
uint64_t orig_size;
uint64_t current_size;
uint16_t cyls;
uint8_t heads;
uint8_t secs_per_cyl;
uint32_t type;
// Checksum of the Hard Disk Footer ("one's complement of the sum of all
// the bytes in the footer without the checksum field")
uint32_t checksum;
// UUID used to identify a parent hard disk (backing file)
uint8_t uuid[16];
uint8_t in_saved_state;
} QEMU_PACKED VHDFooter;
typedef struct vhd_dyndisk_header {
char magic[8]; // "cxsparse"
// Offset of next header structure, 0xFFFFFFFF if none
uint64_t data_offset;
// Offset of the Block Allocation Table (BAT)
uint64_t table_offset;
uint32_t version;
uint32_t max_table_entries; // 32bit/entry
// 2 MB by default, must be a power of two
uint32_t block_size;
uint32_t checksum;
uint8_t parent_uuid[16];
uint32_t parent_timestamp;
uint32_t reserved;
// Backing file name (in UTF-16)
uint8_t parent_name[512];
struct {
uint32_t platform;
uint32_t data_space;
uint32_t data_length;
uint32_t reserved;
uint64_t data_offset;
} parent_locator[8];
} QEMU_PACKED VHDDynDiskHeader;
typedef struct BDRVVPCState {
CoMutex lock;
uint8_t footer_buf[HEADER_SIZE];
uint64_t free_data_block_offset;
int max_table_entries;
uint32_t *pagetable;
uint64_t bat_offset;
uint64_t last_bitmap_offset;
uint32_t block_size;
uint32_t bitmap_size;
bool force_use_chs;
bool force_use_sz;
#ifdef CACHE
uint8_t *pageentry_u8;
uint32_t *pageentry_u32;
uint16_t *pageentry_u16;
uint64_t last_bitmap;
#endif
Error *migration_blocker;
} BDRVVPCState;
#define VPC_OPT_SIZE_CALC "force_size_calc"
static QemuOptsList vpc_runtime_opts = {
.name = "vpc-runtime-opts",
.head = QTAILQ_HEAD_INITIALIZER(vpc_runtime_opts.head),
.desc = {
{
.name = VPC_OPT_SIZE_CALC,
.type = QEMU_OPT_STRING,
.help = "Force disk size calculation to use either CHS geometry, "
"or use the disk current_size specified in the VHD footer. "
"{chs, current_size}"
},
{ /* end of list */ }
}
};
static uint32_t vpc_checksum(uint8_t* buf, size_t size)
{
uint32_t res = 0;
int i;
for (i = 0; i < size; i++)
res += buf[i];
return ~res;
}
static int vpc_probe(const uint8_t *buf, int buf_size, const char *filename)
{
if (buf_size >= 8 && !strncmp((char *)buf, "conectix", 8))
return 100;
return 0;
}
static void vpc_parse_options(BlockDriverState *bs, QemuOpts *opts,
Error **errp)
{
BDRVVPCState *s = bs->opaque;
const char *size_calc;
size_calc = qemu_opt_get(opts, VPC_OPT_SIZE_CALC);
if (!size_calc) {
/* no override, use autodetect only */
} else if (!strcmp(size_calc, "current_size")) {
s->force_use_sz = true;
} else if (!strcmp(size_calc, "chs")) {
s->force_use_chs = true;
} else {
error_setg(errp, "Invalid size calculation mode: '%s'", size_calc);
}
}
static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVVPCState *s = bs->opaque;
int i;
VHDFooter *footer;
VHDDynDiskHeader *dyndisk_header;
QemuOpts *opts = NULL;
Error *local_err = NULL;
bool use_chs;
uint8_t buf[HEADER_SIZE];
uint32_t checksum;
uint64_t computed_size;
uint64_t pagetable_size;
int disk_type = VHD_DYNAMIC;
int ret;
opts = qemu_opts_create(&vpc_runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
vpc_parse_options(bs, opts, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
ret = bdrv_pread(bs->file->bs, 0, s->footer_buf, HEADER_SIZE);
if (ret < 0) {
goto fail;
}
footer = (VHDFooter *) s->footer_buf;
if (strncmp(footer->creator, "conectix", 8)) {
int64_t offset = bdrv_getlength(bs->file->bs);
if (offset < 0) {
ret = offset;
goto fail;
} else if (offset < HEADER_SIZE) {
ret = -EINVAL;
goto fail;
}
/* If a fixed disk, the footer is found only at the end of the file */
ret = bdrv_pread(bs->file->bs, offset-HEADER_SIZE, s->footer_buf,
HEADER_SIZE);
if (ret < 0) {
goto fail;
}
if (strncmp(footer->creator, "conectix", 8)) {
error_setg(errp, "invalid VPC image");
ret = -EINVAL;
goto fail;
}
disk_type = VHD_FIXED;
}
checksum = be32_to_cpu(footer->checksum);
footer->checksum = 0;
if (vpc_checksum(s->footer_buf, HEADER_SIZE) != checksum)
fprintf(stderr, "block-vpc: The header checksum of '%s' is "
"incorrect.\n", bs->filename);
/* Write 'checksum' back to footer, or else will leave it with zero. */
footer->checksum = cpu_to_be32(checksum);
// The visible size of a image in Virtual PC depends on the geometry
// rather than on the size stored in the footer (the size in the footer
// is too large usually)
bs->total_sectors = (int64_t)
be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl;
/* Microsoft Virtual PC and Microsoft Hyper-V produce and read
* VHD image sizes differently. VPC will rely on CHS geometry,
* while Hyper-V and disk2vhd use the size specified in the footer.
*
* We use a couple of approaches to try and determine the correct method:
* look at the Creator App field, and look for images that have CHS
* geometry that is the maximum value.
*
* If the CHS geometry is the maximum CHS geometry, then we assume that
* the size is the footer->current_size to avoid truncation. Otherwise,
* we follow the table based on footer->creator_app:
*
* Known creator apps:
* 'vpc ' : CHS Virtual PC (uses disk geometry)
* 'qemu' : CHS QEMU (uses disk geometry)
* 'qem2' : current_size QEMU (uses current_size)
* 'win ' : current_size Hyper-V
* 'd2v ' : current_size Disk2vhd
*
* The user can override the table values via drive options, however
* even with an override we will still use current_size for images
* that have CHS geometry of the maximum size.
*/
use_chs = (!!strncmp(footer->creator_app, "win ", 4) &&
!!strncmp(footer->creator_app, "qem2", 4) &&
!!strncmp(footer->creator_app, "d2v ", 4)) || s->force_use_chs;
if (!use_chs || bs->total_sectors == VHD_MAX_GEOMETRY || s->force_use_sz) {
bs->total_sectors = be64_to_cpu(footer->current_size) /
BDRV_SECTOR_SIZE;
}
/* Allow a maximum disk size of approximately 2 TB */
if (bs->total_sectors >= VHD_MAX_SECTORS) {
ret = -EFBIG;
goto fail;
}
if (disk_type == VHD_DYNAMIC) {
ret = bdrv_pread(bs->file->bs, be64_to_cpu(footer->data_offset), buf,
HEADER_SIZE);
if (ret < 0) {
goto fail;
}
dyndisk_header = (VHDDynDiskHeader *) buf;
if (strncmp(dyndisk_header->magic, "cxsparse", 8)) {
ret = -EINVAL;
goto fail;
}
s->block_size = be32_to_cpu(dyndisk_header->block_size);
if (!is_power_of_2(s->block_size) || s->block_size < BDRV_SECTOR_SIZE) {
error_setg(errp, "Invalid block size %" PRIu32, s->block_size);
ret = -EINVAL;
goto fail;
}
s->bitmap_size = ((s->block_size / (8 * 512)) + 511) & ~511;
s->max_table_entries = be32_to_cpu(dyndisk_header->max_table_entries);
if ((bs->total_sectors * 512) / s->block_size > 0xffffffffU) {
ret = -EINVAL;
goto fail;
}
if (s->max_table_entries > (VHD_MAX_SECTORS * 512) / s->block_size) {
ret = -EINVAL;
goto fail;
}
computed_size = (uint64_t) s->max_table_entries * s->block_size;
if (computed_size < bs->total_sectors * 512) {
ret = -EINVAL;
goto fail;
}
if (s->max_table_entries > SIZE_MAX / 4 ||
s->max_table_entries > (int) INT_MAX / 4) {
error_setg(errp, "Max Table Entries too large (%" PRId32 ")",
s->max_table_entries);
ret = -EINVAL;
goto fail;
}
pagetable_size = (uint64_t) s->max_table_entries * 4;
s->pagetable = qemu_try_blockalign(bs->file->bs, pagetable_size);
if (s->pagetable == NULL) {
ret = -ENOMEM;
goto fail;
}
s->bat_offset = be64_to_cpu(dyndisk_header->table_offset);
ret = bdrv_pread(bs->file->bs, s->bat_offset, s->pagetable,
pagetable_size);
if (ret < 0) {
goto fail;
}
s->free_data_block_offset =
ROUND_UP(s->bat_offset + pagetable_size, 512);
for (i = 0; i < s->max_table_entries; i++) {
be32_to_cpus(&s->pagetable[i]);
if (s->pagetable[i] != 0xFFFFFFFF) {
int64_t next = (512 * (int64_t) s->pagetable[i]) +
s->bitmap_size + s->block_size;
if (next > s->free_data_block_offset) {
s->free_data_block_offset = next;
}
}
}
if (s->free_data_block_offset > bdrv_getlength(bs->file->bs)) {
error_setg(errp, "block-vpc: free_data_block_offset points after "
"the end of file. The image has been truncated.");
ret = -EINVAL;
goto fail;
}
s->last_bitmap_offset = (int64_t) -1;
#ifdef CACHE
s->pageentry_u8 = g_malloc(512);
s->pageentry_u32 = s->pageentry_u8;
s->pageentry_u16 = s->pageentry_u8;
s->last_pagetable = -1;
#endif
}
qemu_co_mutex_init(&s->lock);
/* Disable migration when VHD images are used */
error_setg(&s->migration_blocker, "The vpc format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
migrate_add_blocker(s->migration_blocker);
return 0;
fail:
qemu_vfree(s->pagetable);
#ifdef CACHE
g_free(s->pageentry_u8);
#endif
return ret;
}
static int vpc_reopen_prepare(BDRVReopenState *state,
BlockReopenQueue *queue, Error **errp)
{
return 0;
}
/*
* Returns the absolute byte offset of the given sector in the image file.
* If the sector is not allocated, -1 is returned instead.
*
* The parameter write must be 1 if the offset will be used for a write
* operation (the block bitmaps is updated then), 0 otherwise.
*/
static inline int64_t get_sector_offset(BlockDriverState *bs,
int64_t sector_num, int write)
{
BDRVVPCState *s = bs->opaque;
uint64_t offset = sector_num * 512;
uint64_t bitmap_offset, block_offset;
uint32_t pagetable_index, pageentry_index;
pagetable_index = offset / s->block_size;
pageentry_index = (offset % s->block_size) / 512;
if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff)
return -1; // not allocated
bitmap_offset = 512 * (uint64_t) s->pagetable[pagetable_index];
block_offset = bitmap_offset + s->bitmap_size + (512 * pageentry_index);
// We must ensure that we don't write to any sectors which are marked as
// unused in the bitmap. We get away with setting all bits in the block
// bitmap each time we write to a new block. This might cause Virtual PC to
// miss sparse read optimization, but it's not a problem in terms of
// correctness.
if (write && (s->last_bitmap_offset != bitmap_offset)) {
uint8_t bitmap[s->bitmap_size];
s->last_bitmap_offset = bitmap_offset;
memset(bitmap, 0xff, s->bitmap_size);
bdrv_pwrite_sync(bs->file->bs, bitmap_offset, bitmap, s->bitmap_size);
}
return block_offset;
}
/*
* Writes the footer to the end of the image file. This is needed when the
* file grows as it overwrites the old footer
*
* Returns 0 on success and < 0 on error
*/
static int rewrite_footer(BlockDriverState* bs)
{
int ret;
BDRVVPCState *s = bs->opaque;
int64_t offset = s->free_data_block_offset;
ret = bdrv_pwrite_sync(bs->file->bs, offset, s->footer_buf, HEADER_SIZE);
if (ret < 0)
return ret;
return 0;
}
/*
* Allocates a new block. This involves writing a new footer and updating
* the Block Allocation Table to use the space at the old end of the image
* file (overwriting the old footer)
*
* Returns the sectors' offset in the image file on success and < 0 on error
*/
static int64_t alloc_block(BlockDriverState* bs, int64_t sector_num)
{
BDRVVPCState *s = bs->opaque;
int64_t bat_offset;
uint32_t index, bat_value;
int ret;
uint8_t bitmap[s->bitmap_size];
// Check if sector_num is valid
if ((sector_num < 0) || (sector_num > bs->total_sectors))
return -1;
// Write entry into in-memory BAT
index = (sector_num * 512) / s->block_size;
if (s->pagetable[index] != 0xFFFFFFFF)
return -1;
s->pagetable[index] = s->free_data_block_offset / 512;
// Initialize the block's bitmap
memset(bitmap, 0xff, s->bitmap_size);
ret = bdrv_pwrite_sync(bs->file->bs, s->free_data_block_offset, bitmap,
s->bitmap_size);
if (ret < 0) {
return ret;
}
// Write new footer (the old one will be overwritten)
s->free_data_block_offset += s->block_size + s->bitmap_size;
ret = rewrite_footer(bs);
if (ret < 0)
goto fail;
// Write BAT entry to disk
bat_offset = s->bat_offset + (4 * index);
bat_value = cpu_to_be32(s->pagetable[index]);
ret = bdrv_pwrite_sync(bs->file->bs, bat_offset, &bat_value, 4);
if (ret < 0)
goto fail;
return get_sector_offset(bs, sector_num, 0);
fail:
s->free_data_block_offset -= (s->block_size + s->bitmap_size);
return -1;
}
static int vpc_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
BDRVVPCState *s = (BDRVVPCState *)bs->opaque;
VHDFooter *footer = (VHDFooter *) s->footer_buf;
if (be32_to_cpu(footer->type) != VHD_FIXED) {
bdi->cluster_size = s->block_size;
}
bdi->unallocated_blocks_are_zero = true;
return 0;
}
static int vpc_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
BDRVVPCState *s = bs->opaque;
int ret;
int64_t offset;
int64_t sectors, sectors_per_block;
VHDFooter *footer = (VHDFooter *) s->footer_buf;
if (be32_to_cpu(footer->type) == VHD_FIXED) {
return bdrv_read(bs->file->bs, sector_num, buf, nb_sectors);
}
while (nb_sectors > 0) {
offset = get_sector_offset(bs, sector_num, 0);
sectors_per_block = s->block_size >> BDRV_SECTOR_BITS;
sectors = sectors_per_block - (sector_num % sectors_per_block);
if (sectors > nb_sectors) {
sectors = nb_sectors;
}
if (offset == -1) {
memset(buf, 0, sectors * BDRV_SECTOR_SIZE);
} else {
ret = bdrv_pread(bs->file->bs, offset, buf,
sectors * BDRV_SECTOR_SIZE);
if (ret != sectors * BDRV_SECTOR_SIZE) {
return -1;
}
}
nb_sectors -= sectors;
sector_num += sectors;
buf += sectors * BDRV_SECTOR_SIZE;
}
return 0;
}
static coroutine_fn int vpc_co_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
int ret;
BDRVVPCState *s = bs->opaque;
qemu_co_mutex_lock(&s->lock);
ret = vpc_read(bs, sector_num, buf, nb_sectors);
qemu_co_mutex_unlock(&s->lock);
return ret;
}
static int vpc_write(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors)
{
BDRVVPCState *s = bs->opaque;
int64_t offset;
int64_t sectors, sectors_per_block;
int ret;
VHDFooter *footer = (VHDFooter *) s->footer_buf;
if (be32_to_cpu(footer->type) == VHD_FIXED) {
return bdrv_write(bs->file->bs, sector_num, buf, nb_sectors);
}
while (nb_sectors > 0) {
offset = get_sector_offset(bs, sector_num, 1);
sectors_per_block = s->block_size >> BDRV_SECTOR_BITS;
sectors = sectors_per_block - (sector_num % sectors_per_block);
if (sectors > nb_sectors) {
sectors = nb_sectors;
}
if (offset == -1) {
offset = alloc_block(bs, sector_num);
if (offset < 0)
return -1;
}
ret = bdrv_pwrite(bs->file->bs, offset, buf,
sectors * BDRV_SECTOR_SIZE);
if (ret != sectors * BDRV_SECTOR_SIZE) {
return -1;
}
nb_sectors -= sectors;
sector_num += sectors;
buf += sectors * BDRV_SECTOR_SIZE;
}
return 0;
}
static coroutine_fn int vpc_co_write(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors)
{
int ret;
BDRVVPCState *s = bs->opaque;
qemu_co_mutex_lock(&s->lock);
ret = vpc_write(bs, sector_num, buf, nb_sectors);
qemu_co_mutex_unlock(&s->lock);
return ret;
}
static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file)
{
BDRVVPCState *s = bs->opaque;
VHDFooter *footer = (VHDFooter*) s->footer_buf;
int64_t start, offset;
bool allocated;
int n;
if (be32_to_cpu(footer->type) == VHD_FIXED) {
*pnum = nb_sectors;
*file = bs->file->bs;
return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
(sector_num << BDRV_SECTOR_BITS);
}
offset = get_sector_offset(bs, sector_num, 0);
start = offset;
allocated = (offset != -1);
*pnum = 0;
do {
/* All sectors in a block are contiguous (without using the bitmap) */
n = ROUND_UP(sector_num + 1, s->block_size / BDRV_SECTOR_SIZE)
- sector_num;
n = MIN(n, nb_sectors);
*pnum += n;
sector_num += n;
nb_sectors -= n;
/* *pnum can't be greater than one block for allocated
* sectors since there is always a bitmap in between. */
if (allocated) {
*file = bs->file->bs;
return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | start;
}
if (nb_sectors == 0) {
break;
}
offset = get_sector_offset(bs, sector_num, 0);
} while (offset == -1);
return 0;
}
/*
* Calculates the number of cylinders, heads and sectors per cylinder
* based on a given number of sectors. This is the algorithm described
* in the VHD specification.
*
* Note that the geometry doesn't always exactly match total_sectors but
* may round it down.
*
* Returns 0 on success, -EFBIG if the size is larger than ~2 TB. Override
* the hardware EIDE and ATA-2 limit of 16 heads (max disk size of 127 GB)
* and instead allow up to 255 heads.
*/
static int calculate_geometry(int64_t total_sectors, uint16_t* cyls,
uint8_t* heads, uint8_t* secs_per_cyl)
{
uint32_t cyls_times_heads;
total_sectors = MIN(total_sectors, VHD_MAX_GEOMETRY);
if (total_sectors >= 65535LL * 16 * 63) {
*secs_per_cyl = 255;
*heads = 16;
cyls_times_heads = total_sectors / *secs_per_cyl;
} else {
*secs_per_cyl = 17;
cyls_times_heads = total_sectors / *secs_per_cyl;
*heads = (cyls_times_heads + 1023) / 1024;
if (*heads < 4) {
*heads = 4;
}
if (cyls_times_heads >= (*heads * 1024) || *heads > 16) {
*secs_per_cyl = 31;
*heads = 16;
cyls_times_heads = total_sectors / *secs_per_cyl;
}
if (cyls_times_heads >= (*heads * 1024)) {
*secs_per_cyl = 63;
*heads = 16;
cyls_times_heads = total_sectors / *secs_per_cyl;
}
}
*cyls = cyls_times_heads / *heads;
return 0;
}
static int create_dynamic_disk(BlockBackend *blk, uint8_t *buf,
int64_t total_sectors)
{
VHDDynDiskHeader *dyndisk_header =
(VHDDynDiskHeader *) buf;
size_t block_size, num_bat_entries;
int i;
int ret;
int64_t offset = 0;
// Write the footer (twice: at the beginning and at the end)
block_size = 0x200000;
num_bat_entries = (total_sectors + block_size / 512) / (block_size / 512);
ret = blk_pwrite(blk, offset, buf, HEADER_SIZE);
if (ret) {
goto fail;
}
offset = 1536 + ((num_bat_entries * 4 + 511) & ~511);
ret = blk_pwrite(blk, offset, buf, HEADER_SIZE);
if (ret < 0) {
goto fail;
}
// Write the initial BAT
offset = 3 * 512;
memset(buf, 0xFF, 512);
for (i = 0; i < (num_bat_entries * 4 + 511) / 512; i++) {
ret = blk_pwrite(blk, offset, buf, 512);
if (ret < 0) {
goto fail;
}
offset += 512;
}
// Prepare the Dynamic Disk Header
memset(buf, 0, 1024);
memcpy(dyndisk_header->magic, "cxsparse", 8);
/*
* Note: The spec is actually wrong here for data_offset, it says
* 0xFFFFFFFF, but MS tools expect all 64 bits to be set.
*/
dyndisk_header->data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL);
dyndisk_header->table_offset = cpu_to_be64(3 * 512);
dyndisk_header->version = cpu_to_be32(0x00010000);
dyndisk_header->block_size = cpu_to_be32(block_size);
dyndisk_header->max_table_entries = cpu_to_be32(num_bat_entries);
dyndisk_header->checksum = cpu_to_be32(vpc_checksum(buf, 1024));
// Write the header
offset = 512;
ret = blk_pwrite(blk, offset, buf, 1024);
if (ret < 0) {
goto fail;
}
fail:
return ret;
}
static int create_fixed_disk(BlockBackend *blk, uint8_t *buf,
int64_t total_size)
{
int ret;
/* Add footer to total size */
total_size += HEADER_SIZE;
ret = blk_truncate(blk, total_size);
if (ret < 0) {
return ret;
}
ret = blk_pwrite(blk, total_size - HEADER_SIZE, buf, HEADER_SIZE);
if (ret < 0) {
return ret;
}
return ret;
}
static int vpc_create(const char *filename, QemuOpts *opts, Error **errp)
{
uint8_t buf[1024];
VHDFooter *footer = (VHDFooter *) buf;
char *disk_type_param;
int i;
uint16_t cyls = 0;
uint8_t heads = 0;
uint8_t secs_per_cyl = 0;
int64_t total_sectors;
int64_t total_size;
int disk_type;
int ret = -EIO;
bool force_size;
Error *local_err = NULL;
BlockBackend *blk = NULL;
/* Read out options */
total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
BDRV_SECTOR_SIZE);
disk_type_param = qemu_opt_get_del(opts, BLOCK_OPT_SUBFMT);
if (disk_type_param) {
if (!strcmp(disk_type_param, "dynamic")) {
disk_type = VHD_DYNAMIC;
} else if (!strcmp(disk_type_param, "fixed")) {
disk_type = VHD_FIXED;
} else {
ret = -EINVAL;
goto out;
}
} else {
disk_type = VHD_DYNAMIC;
}
force_size = qemu_opt_get_bool_del(opts, VPC_OPT_FORCE_SIZE, false);
ret = bdrv_create_file(filename, opts, &local_err);
if (ret < 0) {
error_propagate(errp, local_err);
goto out;
}
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 out;
}
blk_set_allow_write_beyond_eof(blk, true);
/*
* Calculate matching total_size and geometry. Increase the number of
* sectors requested until we get enough (or fail). This ensures that
* qemu-img convert doesn't truncate images, but rather rounds up.
*
* If the image size can't be represented by a spec conformant CHS geometry,
* we set the geometry to 65535 x 16 x 255 (CxHxS) sectors and use
* the image size from the VHD footer to calculate total_sectors.
*/
if (force_size) {
/* This will force the use of total_size for sector count, below */
cyls = VHD_CHS_MAX_C;
heads = VHD_CHS_MAX_H;
secs_per_cyl = VHD_CHS_MAX_S;
} else {
total_sectors = MIN(VHD_MAX_GEOMETRY, total_size / BDRV_SECTOR_SIZE);
for (i = 0; total_sectors > (int64_t)cyls * heads * secs_per_cyl; i++) {
calculate_geometry(total_sectors + i, &cyls, &heads, &secs_per_cyl);
}
}
if ((int64_t)cyls * heads * secs_per_cyl == VHD_MAX_GEOMETRY) {
total_sectors = total_size / BDRV_SECTOR_SIZE;
/* Allow a maximum disk size of approximately 2 TB */
if (total_sectors > VHD_MAX_SECTORS) {
ret = -EFBIG;
goto out;
}
} else {
total_sectors = (int64_t)cyls * heads * secs_per_cyl;
total_size = total_sectors * BDRV_SECTOR_SIZE;
}
/* Prepare the Hard Disk Footer */
memset(buf, 0, 1024);
memcpy(footer->creator, "conectix", 8);
if (force_size) {
memcpy(footer->creator_app, "qem2", 4);
} else {
memcpy(footer->creator_app, "qemu", 4);
}
memcpy(footer->creator_os, "Wi2k", 4);
footer->features = cpu_to_be32(0x02);
footer->version = cpu_to_be32(0x00010000);
if (disk_type == VHD_DYNAMIC) {
footer->data_offset = cpu_to_be64(HEADER_SIZE);
} else {
footer->data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL);
}
footer->timestamp = cpu_to_be32(time(NULL) - VHD_TIMESTAMP_BASE);
/* Version of Virtual PC 2007 */
footer->major = cpu_to_be16(0x0005);
footer->minor = cpu_to_be16(0x0003);
footer->orig_size = cpu_to_be64(total_size);
footer->current_size = cpu_to_be64(total_size);
footer->cyls = cpu_to_be16(cyls);
footer->heads = heads;
footer->secs_per_cyl = secs_per_cyl;
footer->type = cpu_to_be32(disk_type);
#if defined(CONFIG_UUID)
uuid_generate(footer->uuid);
#endif
footer->checksum = cpu_to_be32(vpc_checksum(buf, HEADER_SIZE));
if (disk_type == VHD_DYNAMIC) {
ret = create_dynamic_disk(blk, buf, total_sectors);
} else {
ret = create_fixed_disk(blk, buf, total_size);
}
out:
blk_unref(blk);
g_free(disk_type_param);
return ret;
}
static int vpc_has_zero_init(BlockDriverState *bs)
{
BDRVVPCState *s = bs->opaque;
VHDFooter *footer = (VHDFooter *) s->footer_buf;
if (be32_to_cpu(footer->type) == VHD_FIXED) {
return bdrv_has_zero_init(bs->file->bs);
} else {
return 1;
}
}
static void vpc_close(BlockDriverState *bs)
{
BDRVVPCState *s = bs->opaque;
qemu_vfree(s->pagetable);
#ifdef CACHE
g_free(s->pageentry_u8);
#endif
migrate_del_blocker(s->migration_blocker);
error_free(s->migration_blocker);
}
static QemuOptsList vpc_create_opts = {
.name = "vpc-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(vpc_create_opts.head),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size"
},
{
.name = BLOCK_OPT_SUBFMT,
.type = QEMU_OPT_STRING,
.help =
"Type of virtual hard disk format. Supported formats are "
"{dynamic (default) | fixed} "
},
{
.name = VPC_OPT_FORCE_SIZE,
.type = QEMU_OPT_BOOL,
.help = "Force disk size calculation to use the actual size "
"specified, rather than using the nearest CHS-based "
"calculation"
},
{ /* end of list */ }
}
};
static BlockDriver bdrv_vpc = {
.format_name = "vpc",
.instance_size = sizeof(BDRVVPCState),
.bdrv_probe = vpc_probe,
.bdrv_open = vpc_open,
.bdrv_close = vpc_close,
.bdrv_reopen_prepare = vpc_reopen_prepare,
.bdrv_create = vpc_create,
.bdrv_read = vpc_co_read,
.bdrv_write = vpc_co_write,
.bdrv_co_get_block_status = vpc_co_get_block_status,
.bdrv_get_info = vpc_get_info,
.create_opts = &vpc_create_opts,
.bdrv_has_zero_init = vpc_has_zero_init,
};
static void bdrv_vpc_init(void)
{
bdrv_register(&bdrv_vpc);
}
block_init(bdrv_vpc_init);
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