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qemu/block/vhdx.c

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/*
* Block driver for Hyper-V VHDX Images
*
* Copyright (c) 2013 Red Hat, Inc.,
*
* Authors:
* Jeff Cody <jcody@redhat.com>
*
* This is based on the "VHDX Format Specification v1.00", published 8/25/2012
* by Microsoft:
* https://www.microsoft.com/en-us/download/details.aspx?id=34750
*
* This work is licensed under the terms of the GNU LGPL, version 2 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#include "qemu-common.h"
#include "block/block_int.h"
#include "qemu/module.h"
#include "qemu/crc32c.h"
#include "block/vhdx.h"
#include "migration/migration.h"
#include <uuid/uuid.h>
#include <glib.h>
/* Options for VHDX creation */
#define VHDX_BLOCK_OPT_LOG_SIZE "log_size"
#define VHDX_BLOCK_OPT_BLOCK_SIZE "block_size"
#define VHDX_BLOCK_OPT_ZERO "block_state_zero"
typedef enum VHDXImageType {
VHDX_TYPE_DYNAMIC = 0,
VHDX_TYPE_FIXED,
VHDX_TYPE_DIFFERENCING, /* Currently unsupported */
} VHDXImageType;
/* Several metadata and region table data entries are identified by
* guids in a MS-specific GUID format. */
/* ------- Known Region Table GUIDs ---------------------- */
static const MSGUID bat_guid = { .data1 = 0x2dc27766,
.data2 = 0xf623,
.data3 = 0x4200,
.data4 = { 0x9d, 0x64, 0x11, 0x5e,
0x9b, 0xfd, 0x4a, 0x08} };
static const MSGUID metadata_guid = { .data1 = 0x8b7ca206,
.data2 = 0x4790,
.data3 = 0x4b9a,
.data4 = { 0xb8, 0xfe, 0x57, 0x5f,
0x05, 0x0f, 0x88, 0x6e} };
/* ------- Known Metadata Entry GUIDs ---------------------- */
static const MSGUID file_param_guid = { .data1 = 0xcaa16737,
.data2 = 0xfa36,
.data3 = 0x4d43,
.data4 = { 0xb3, 0xb6, 0x33, 0xf0,
0xaa, 0x44, 0xe7, 0x6b} };
static const MSGUID virtual_size_guid = { .data1 = 0x2FA54224,
.data2 = 0xcd1b,
.data3 = 0x4876,
.data4 = { 0xb2, 0x11, 0x5d, 0xbe,
0xd8, 0x3b, 0xf4, 0xb8} };
static const MSGUID page83_guid = { .data1 = 0xbeca12ab,
.data2 = 0xb2e6,
.data3 = 0x4523,
.data4 = { 0x93, 0xef, 0xc3, 0x09,
0xe0, 0x00, 0xc7, 0x46} };
static const MSGUID phys_sector_guid = { .data1 = 0xcda348c7,
.data2 = 0x445d,
.data3 = 0x4471,
.data4 = { 0x9c, 0xc9, 0xe9, 0x88,
0x52, 0x51, 0xc5, 0x56} };
static const MSGUID parent_locator_guid = { .data1 = 0xa8d35f2d,
.data2 = 0xb30b,
.data3 = 0x454d,
.data4 = { 0xab, 0xf7, 0xd3,
0xd8, 0x48, 0x34,
0xab, 0x0c} };
static const MSGUID logical_sector_guid = { .data1 = 0x8141bf1d,
.data2 = 0xa96f,
.data3 = 0x4709,
.data4 = { 0xba, 0x47, 0xf2,
0x33, 0xa8, 0xfa,
0xab, 0x5f} };
/* Each parent type must have a valid GUID; this is for parent images
* of type 'VHDX'. If we were to allow e.g. a QCOW2 parent, we would
* need to make up our own QCOW2 GUID type */
static const MSGUID parent_vhdx_guid = { .data1 = 0xb04aefb7,
.data2 = 0xd19e,
.data3 = 0x4a81,
.data4 = { 0xb7, 0x89, 0x25, 0xb8,
0xe9, 0x44, 0x59, 0x13} };
#define META_FILE_PARAMETER_PRESENT 0x01
#define META_VIRTUAL_DISK_SIZE_PRESENT 0x02
#define META_PAGE_83_PRESENT 0x04
#define META_LOGICAL_SECTOR_SIZE_PRESENT 0x08
#define META_PHYS_SECTOR_SIZE_PRESENT 0x10
#define META_PARENT_LOCATOR_PRESENT 0x20
#define META_ALL_PRESENT \
(META_FILE_PARAMETER_PRESENT | META_VIRTUAL_DISK_SIZE_PRESENT | \
META_PAGE_83_PRESENT | META_LOGICAL_SECTOR_SIZE_PRESENT | \
META_PHYS_SECTOR_SIZE_PRESENT)
typedef struct VHDXSectorInfo {
uint32_t bat_idx; /* BAT entry index */
uint32_t sectors_avail; /* sectors available in payload block */
uint32_t bytes_left; /* bytes left in the block after data to r/w */
uint32_t bytes_avail; /* bytes available in payload block */
uint64_t file_offset; /* absolute offset in bytes, in file */
uint64_t block_offset; /* block offset, in bytes */
} VHDXSectorInfo;
/* Calculates new checksum.
*
* Zero is substituted during crc calculation for the original crc field
* crc_offset: byte offset in buf of the buffer crc
* buf: buffer pointer
* size: size of buffer (must be > crc_offset+4)
*
* Note: The resulting checksum is in the CPU endianness, not necessarily
* in the file format endianness (LE). Any header export to disk should
* make sure that vhdx_header_le_export() is used to convert to the
* correct endianness
*/
uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset)
{
uint32_t crc;
assert(buf != NULL);
assert(size > (crc_offset + sizeof(crc)));
memset(buf + crc_offset, 0, sizeof(crc));
crc = crc32c(0xffffffff, buf, size);
memcpy(buf + crc_offset, &crc, sizeof(crc));
return crc;
}
uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
int crc_offset)
{
uint32_t crc_new;
uint32_t crc_orig;
assert(buf != NULL);
if (crc_offset > 0) {
memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
memset(buf + crc_offset, 0, sizeof(crc_orig));
}
crc_new = crc32c(crc, buf, size);
if (crc_offset > 0) {
memcpy(buf + crc_offset, &crc_orig, sizeof(crc_orig));
}
return crc_new;
}
/* Validates the checksum of the buffer, with an in-place CRC.
*
* Zero is substituted during crc calculation for the original crc field,
* and the crc field is restored afterwards. But the buffer will be modifed
* during the calculation, so this may not be not suitable for multi-threaded
* use.
*
* crc_offset: byte offset in buf of the buffer crc
* buf: buffer pointer
* size: size of buffer (must be > crc_offset+4)
*
* returns true if checksum is valid, false otherwise
*/
bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset)
{
uint32_t crc_orig;
uint32_t crc;
assert(buf != NULL);
assert(size > (crc_offset + 4));
memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
crc_orig = le32_to_cpu(crc_orig);
crc = vhdx_checksum_calc(0xffffffff, buf, size, crc_offset);
return crc == crc_orig;
}
/*
* This generates a UUID that is compliant with the MS GUIDs used
* in the VHDX spec (and elsewhere).
*/
void vhdx_guid_generate(MSGUID *guid)
{
uuid_t uuid;
assert(guid != NULL);
uuid_generate(uuid);
memcpy(guid, uuid, sizeof(MSGUID));
}
/* Check for region overlaps inside the VHDX image */
static int vhdx_region_check(BDRVVHDXState *s, uint64_t start, uint64_t length)
{
int ret = 0;
uint64_t end;
VHDXRegionEntry *r;
end = start + length;
QLIST_FOREACH(r, &s->regions, entries) {
if (!((start >= r->end) || (end <= r->start))) {
ret = -EINVAL;
goto exit;
}
}
exit:
return ret;
}
/* Register a region for future checks */
static void vhdx_region_register(BDRVVHDXState *s,
uint64_t start, uint64_t length)
{
VHDXRegionEntry *r;
r = g_malloc0(sizeof(*r));
r->start = start;
r->end = start + length;
QLIST_INSERT_HEAD(&s->regions, r, entries);
}
/* Free all registered regions */
static void vhdx_region_unregister_all(BDRVVHDXState *s)
{
VHDXRegionEntry *r, *r_next;
QLIST_FOREACH_SAFE(r, &s->regions, entries, r_next) {
QLIST_REMOVE(r, entries);
g_free(r);
}
}
static void vhdx_set_shift_bits(BDRVVHDXState *s)
{
s->logical_sector_size_bits = 31 - clz32(s->logical_sector_size);
s->sectors_per_block_bits = 31 - clz32(s->sectors_per_block);
s->chunk_ratio_bits = 63 - clz64(s->chunk_ratio);
s->block_size_bits = 31 - clz32(s->block_size);
}
/*
* Per the MS VHDX Specification, for every VHDX file:
* - The header section is fixed size - 1 MB
* - The header section is always the first "object"
* - The first 64KB of the header is the File Identifier
* - The first uint64 (8 bytes) is the VHDX Signature ("vhdxfile")
* - The following 512 bytes constitute a UTF-16 string identifiying the
* software that created the file, and is optional and diagnostic only.
*
* Therefore, we probe by looking for the vhdxfile signature "vhdxfile"
*/
static int vhdx_probe(const uint8_t *buf, int buf_size, const char *filename)
{
if (buf_size >= 8 && !memcmp(buf, "vhdxfile", 8)) {
return 100;
}
return 0;
}
/*
* Writes the header to the specified offset.
*
* This will optionally read in buffer data from disk (otherwise zero-fill),
* and then update the header checksum. Header is converted to proper
* endianness before being written to the specified file offset
*/
static int vhdx_write_header(BlockDriverState *bs_file, VHDXHeader *hdr,
uint64_t offset, bool read)
{
uint8_t *buffer = NULL;
int ret;
VHDXHeader header_le;
assert(bs_file != NULL);
assert(hdr != NULL);
/* the header checksum is not over just the packed size of VHDXHeader,
* but rather over the entire 'reserved' range for the header, which is
* 4KB (VHDX_HEADER_SIZE). */
buffer = qemu_blockalign(bs_file, VHDX_HEADER_SIZE);
if (read) {
/* if true, we can't assume the extra reserved bytes are 0 */
ret = bdrv_pread(bs_file, offset, buffer, VHDX_HEADER_SIZE);
if (ret < 0) {
goto exit;
}
} else {
memset(buffer, 0, VHDX_HEADER_SIZE);
}
/* overwrite the actual VHDXHeader portion */
memcpy(buffer, hdr, sizeof(VHDXHeader));
hdr->checksum = vhdx_update_checksum(buffer, VHDX_HEADER_SIZE,
offsetof(VHDXHeader, checksum));
vhdx_header_le_export(hdr, &header_le);
ret = bdrv_pwrite_sync(bs_file, offset, &header_le, sizeof(VHDXHeader));
exit:
qemu_vfree(buffer);
return ret;
}
/* Update the VHDX headers
*
* This follows the VHDX spec procedures for header updates.
*
* - non-current header is updated with largest sequence number
*/
static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s,
bool generate_data_write_guid, MSGUID *log_guid)
{
int ret = 0;
int hdr_idx = 0;
uint64_t header_offset = VHDX_HEADER1_OFFSET;
VHDXHeader *active_header;
VHDXHeader *inactive_header;
/* operate on the non-current header */
if (s->curr_header == 0) {
hdr_idx = 1;
header_offset = VHDX_HEADER2_OFFSET;
}
active_header = s->headers[s->curr_header];
inactive_header = s->headers[hdr_idx];
inactive_header->sequence_number = active_header->sequence_number + 1;
/* a new file guid must be generated before any file write, including
* headers */
inactive_header->file_write_guid = s->session_guid;
/* a new data guid only needs to be generated before any guest-visible
* writes (i.e. something observable via virtual disk read) */
if (generate_data_write_guid) {
vhdx_guid_generate(&inactive_header->data_write_guid);
}
/* update the log guid if present */
if (log_guid) {
inactive_header->log_guid = *log_guid;
}
ret = vhdx_write_header(bs->file, inactive_header, header_offset, true);
if (ret < 0) {
goto exit;
}
s->curr_header = hdr_idx;
exit:
return ret;
}
/*
* The VHDX spec calls for header updates to be performed twice, so that both
* the current and non-current header have valid info
*/
int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s,
bool generate_data_write_guid, MSGUID *log_guid)
{
int ret;
ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
if (ret < 0) {
return ret;
}
ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
return ret;
}
/* opens the specified header block from the VHDX file header section */
static void vhdx_parse_header(BlockDriverState *bs, BDRVVHDXState *s,
Error **errp)
{
int ret;
VHDXHeader *header1;
VHDXHeader *header2;
bool h1_valid = false;
bool h2_valid = false;
uint64_t h1_seq = 0;
uint64_t h2_seq = 0;
uint8_t *buffer;
/* header1 & header2 are freed in vhdx_close() */
header1 = qemu_blockalign(bs, sizeof(VHDXHeader));
header2 = qemu_blockalign(bs, sizeof(VHDXHeader));
buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE);
s->headers[0] = header1;
s->headers[1] = header2;
/* We have to read the whole VHDX_HEADER_SIZE instead of
* sizeof(VHDXHeader), because the checksum is over the whole
* region */
ret = bdrv_pread(bs->file, VHDX_HEADER1_OFFSET, buffer, VHDX_HEADER_SIZE);
if (ret < 0) {
goto fail;
}
/* copy over just the relevant portion that we need */
memcpy(header1, buffer, sizeof(VHDXHeader));
vhdx_header_le_import(header1);
if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4) &&
!memcmp(&header1->signature, "head", 4) &&
header1->version == 1) {
h1_seq = header1->sequence_number;
h1_valid = true;
}
ret = bdrv_pread(bs->file, VHDX_HEADER2_OFFSET, buffer, VHDX_HEADER_SIZE);
if (ret < 0) {
goto fail;
}
/* copy over just the relevant portion that we need */
memcpy(header2, buffer, sizeof(VHDXHeader));
vhdx_header_le_import(header2);
if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4) &&
!memcmp(&header2->signature, "head", 4) &&
header2->version == 1) {
h2_seq = header2->sequence_number;
h2_valid = true;
}
/* If there is only 1 valid header (or no valid headers), we
* don't care what the sequence numbers are */
if (h1_valid && !h2_valid) {
s->curr_header = 0;
} else if (!h1_valid && h2_valid) {
s->curr_header = 1;
} else if (!h1_valid && !h2_valid) {
goto fail;
} else {
/* If both headers are valid, then we choose the active one by the
* highest sequence number. If the sequence numbers are equal, that is
* invalid */
if (h1_seq > h2_seq) {
s->curr_header = 0;
} else if (h2_seq > h1_seq) {
s->curr_header = 1;
} else {
/* The Microsoft Disk2VHD tool will create 2 identical
* headers, with identical sequence numbers. If the headers are
* identical, don't consider the file corrupt */
if (!memcmp(header1, header2, sizeof(VHDXHeader))) {
s->curr_header = 0;
} else {
goto fail;
}
}
}
vhdx_region_register(s, s->headers[s->curr_header]->log_offset,
s->headers[s->curr_header]->log_length);
goto exit;
fail:
error_setg_errno(errp, -ret, "No valid VHDX header found");
qemu_vfree(header1);
qemu_vfree(header2);
s->headers[0] = NULL;
s->headers[1] = NULL;
exit:
qemu_vfree(buffer);
}
static int vhdx_open_region_tables(BlockDriverState *bs, BDRVVHDXState *s)
{
int ret = 0;
uint8_t *buffer;
int offset = 0;
VHDXRegionTableEntry rt_entry;
uint32_t i;
bool bat_rt_found = false;
bool metadata_rt_found = false;
/* We have to read the whole 64KB block, because the crc32 is over the
* whole block */
buffer = qemu_blockalign(bs, VHDX_HEADER_BLOCK_SIZE);
ret = bdrv_pread(bs->file, VHDX_REGION_TABLE_OFFSET, buffer,
VHDX_HEADER_BLOCK_SIZE);
if (ret < 0) {
goto fail;
}
memcpy(&s->rt, buffer, sizeof(s->rt));
vhdx_region_header_le_import(&s->rt);
offset += sizeof(s->rt);
if (!vhdx_checksum_is_valid(buffer, VHDX_HEADER_BLOCK_SIZE, 4) ||
memcmp(&s->rt.signature, "regi", 4)) {
ret = -EINVAL;
goto fail;
}
/* Per spec, maximum region table entry count is 2047 */
if (s->rt.entry_count > 2047) {
ret = -EINVAL;
goto fail;
}
for (i = 0; i < s->rt.entry_count; i++) {
memcpy(&rt_entry, buffer + offset, sizeof(rt_entry));
offset += sizeof(rt_entry);
vhdx_region_entry_le_import(&rt_entry);
/* check for region overlap between these entries, and any
* other memory regions in the file */
ret = vhdx_region_check(s, rt_entry.file_offset, rt_entry.length);
if (ret < 0) {
goto fail;
}
vhdx_region_register(s, rt_entry.file_offset, rt_entry.length);
/* see if we recognize the entry */
if (guid_eq(rt_entry.guid, bat_guid)) {
/* must be unique; if we have already found it this is invalid */
if (bat_rt_found) {
ret = -EINVAL;
goto fail;
}
bat_rt_found = true;
s->bat_rt = rt_entry;
continue;
}
if (guid_eq(rt_entry.guid, metadata_guid)) {
/* must be unique; if we have already found it this is invalid */
if (metadata_rt_found) {
ret = -EINVAL;
goto fail;
}
metadata_rt_found = true;
s->metadata_rt = rt_entry;
continue;
}
if (rt_entry.data_bits & VHDX_REGION_ENTRY_REQUIRED) {
/* cannot read vhdx file - required region table entry that
* we do not understand. per spec, we must fail to open */
ret = -ENOTSUP;
goto fail;
}
}
if (!bat_rt_found || !metadata_rt_found) {
ret = -EINVAL;
goto fail;
}
ret = 0;
fail:
qemu_vfree(buffer);
return ret;
}
/* Metadata initial parser
*
* This loads all the metadata entry fields. This may cause additional
* fields to be processed (e.g. parent locator, etc..).
*
* There are 5 Metadata items that are always required:
* - File Parameters (block size, has a parent)
* - Virtual Disk Size (size, in bytes, of the virtual drive)
* - Page 83 Data (scsi page 83 guid)
* - Logical Sector Size (logical sector size in bytes, either 512 or
* 4096. We only support 512 currently)
* - Physical Sector Size (512 or 4096)
*
* Also, if the File Parameters indicate this is a differencing file,
* we must also look for the Parent Locator metadata item.
*/
static int vhdx_parse_metadata(BlockDriverState *bs, BDRVVHDXState *s)
{
int ret = 0;
uint8_t *buffer;
int offset = 0;
uint32_t i = 0;
VHDXMetadataTableEntry md_entry;
buffer = qemu_blockalign(bs, VHDX_METADATA_TABLE_MAX_SIZE);
ret = bdrv_pread(bs->file, s->metadata_rt.file_offset, buffer,
VHDX_METADATA_TABLE_MAX_SIZE);
if (ret < 0) {
goto exit;
}
memcpy(&s->metadata_hdr, buffer, sizeof(s->metadata_hdr));
offset += sizeof(s->metadata_hdr);
vhdx_metadata_header_le_import(&s->metadata_hdr);
if (memcmp(&s->metadata_hdr.signature, "metadata", 8)) {
ret = -EINVAL;
goto exit;
}
s->metadata_entries.present = 0;
if ((s->metadata_hdr.entry_count * sizeof(md_entry)) >
(VHDX_METADATA_TABLE_MAX_SIZE - offset)) {
ret = -EINVAL;
goto exit;
}
for (i = 0; i < s->metadata_hdr.entry_count; i++) {
memcpy(&md_entry, buffer + offset, sizeof(md_entry));
offset += sizeof(md_entry);
vhdx_metadata_entry_le_import(&md_entry);
if (guid_eq(md_entry.item_id, file_param_guid)) {
if (s->metadata_entries.present & META_FILE_PARAMETER_PRESENT) {
ret = -EINVAL;
goto exit;
}
s->metadata_entries.file_parameters_entry = md_entry;
s->metadata_entries.present |= META_FILE_PARAMETER_PRESENT;
continue;
}
if (guid_eq(md_entry.item_id, virtual_size_guid)) {
if (s->metadata_entries.present & META_VIRTUAL_DISK_SIZE_PRESENT) {
ret = -EINVAL;
goto exit;
}
s->metadata_entries.virtual_disk_size_entry = md_entry;
s->metadata_entries.present |= META_VIRTUAL_DISK_SIZE_PRESENT;
continue;
}
if (guid_eq(md_entry.item_id, page83_guid)) {
if (s->metadata_entries.present & META_PAGE_83_PRESENT) {
ret = -EINVAL;
goto exit;
}
s->metadata_entries.page83_data_entry = md_entry;
s->metadata_entries.present |= META_PAGE_83_PRESENT;
continue;
}
if (guid_eq(md_entry.item_id, logical_sector_guid)) {
if (s->metadata_entries.present &
META_LOGICAL_SECTOR_SIZE_PRESENT) {
ret = -EINVAL;
goto exit;
}
s->metadata_entries.logical_sector_size_entry = md_entry;
s->metadata_entries.present |= META_LOGICAL_SECTOR_SIZE_PRESENT;
continue;
}
if (guid_eq(md_entry.item_id, phys_sector_guid)) {
if (s->metadata_entries.present & META_PHYS_SECTOR_SIZE_PRESENT) {
ret = -EINVAL;
goto exit;
}
s->metadata_entries.phys_sector_size_entry = md_entry;
s->metadata_entries.present |= META_PHYS_SECTOR_SIZE_PRESENT;
continue;
}
if (guid_eq(md_entry.item_id, parent_locator_guid)) {
if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
ret = -EINVAL;
goto exit;
}
s->metadata_entries.parent_locator_entry = md_entry;
s->metadata_entries.present |= META_PARENT_LOCATOR_PRESENT;
continue;
}
if (md_entry.data_bits & VHDX_META_FLAGS_IS_REQUIRED) {
/* cannot read vhdx file - required region table entry that
* we do not understand. per spec, we must fail to open */
ret = -ENOTSUP;
goto exit;
}
}
if (s->metadata_entries.present != META_ALL_PRESENT) {
ret = -ENOTSUP;
goto exit;
}
ret = bdrv_pread(bs->file,
s->metadata_entries.file_parameters_entry.offset
+ s->metadata_rt.file_offset,
&s->params,
sizeof(s->params));
if (ret < 0) {
goto exit;
}
le32_to_cpus(&s->params.block_size);
le32_to_cpus(&s->params.data_bits);
/* We now have the file parameters, so we can tell if this is a
* differencing file (i.e.. has_parent), is dynamic or fixed
* sized (leave_blocks_allocated), and the block size */
/* The parent locator required iff the file parameters has_parent set */
if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
/* TODO: parse parent locator fields */
ret = -ENOTSUP; /* temp, until differencing files are supported */
goto exit;
} else {
/* if has_parent is set, but there is not parent locator present,
* then that is an invalid combination */
ret = -EINVAL;
goto exit;
}
}
/* determine virtual disk size, logical sector size,
* and phys sector size */
ret = bdrv_pread(bs->file,
s->metadata_entries.virtual_disk_size_entry.offset
+ s->metadata_rt.file_offset,
&s->virtual_disk_size,
sizeof(uint64_t));
if (ret < 0) {
goto exit;
}
ret = bdrv_pread(bs->file,
s->metadata_entries.logical_sector_size_entry.offset
+ s->metadata_rt.file_offset,
&s->logical_sector_size,
sizeof(uint32_t));
if (ret < 0) {
goto exit;
}
ret = bdrv_pread(bs->file,
s->metadata_entries.phys_sector_size_entry.offset
+ s->metadata_rt.file_offset,
&s->physical_sector_size,
sizeof(uint32_t));
if (ret < 0) {
goto exit;
}
le64_to_cpus(&s->virtual_disk_size);
le32_to_cpus(&s->logical_sector_size);
le32_to_cpus(&s->physical_sector_size);
if (s->params.block_size < VHDX_BLOCK_SIZE_MIN ||
s->params.block_size > VHDX_BLOCK_SIZE_MAX) {
ret = -EINVAL;
goto exit;
}
/* only 2 supported sector sizes */
if (s->logical_sector_size != 512 && s->logical_sector_size != 4096) {
ret = -EINVAL;
goto exit;
}
/* Both block_size and sector_size are guaranteed powers of 2, below.
Due to range checks above, s->sectors_per_block can never be < 256 */
s->sectors_per_block = s->params.block_size / s->logical_sector_size;
s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
(uint64_t)s->logical_sector_size /
(uint64_t)s->params.block_size;
/* These values are ones we will want to use for division / multiplication
* later on, and they are all guaranteed (per the spec) to be powers of 2,
* so we can take advantage of that for shift operations during
* reads/writes */
if (s->logical_sector_size & (s->logical_sector_size - 1)) {
ret = -EINVAL;
goto exit;
}
if (s->sectors_per_block & (s->sectors_per_block - 1)) {
ret = -EINVAL;
goto exit;
}
if (s->chunk_ratio & (s->chunk_ratio - 1)) {
ret = -EINVAL;
goto exit;
}
s->block_size = s->params.block_size;
if (s->block_size & (s->block_size - 1)) {
ret = -EINVAL;
goto exit;
}
vhdx_set_shift_bits(s);
ret = 0;
exit:
qemu_vfree(buffer);
return ret;
}
/*
* Calculate the number of BAT entries, including sector
* bitmap entries.
*/
static void vhdx_calc_bat_entries(BDRVVHDXState *s)
{
uint32_t data_blocks_cnt, bitmap_blocks_cnt;
data_blocks_cnt = s->virtual_disk_size >> s->block_size_bits;
if (s->virtual_disk_size - (data_blocks_cnt << s->block_size_bits)) {
data_blocks_cnt++;
}
bitmap_blocks_cnt = data_blocks_cnt >> s->chunk_ratio_bits;
if (data_blocks_cnt - (bitmap_blocks_cnt << s->chunk_ratio_bits)) {
bitmap_blocks_cnt++;
}
if (s->parent_entries) {
s->bat_entries = bitmap_blocks_cnt * (s->chunk_ratio + 1);
} else {
s->bat_entries = data_blocks_cnt +
((data_blocks_cnt - 1) >> s->chunk_ratio_bits);
}
}
static void vhdx_close(BlockDriverState *bs)
{
BDRVVHDXState *s = bs->opaque;
qemu_vfree(s->headers[0]);
s->headers[0] = NULL;
qemu_vfree(s->headers[1]);
s->headers[1] = NULL;
qemu_vfree(s->bat);
s->bat = NULL;
qemu_vfree(s->parent_entries);
s->parent_entries = NULL;
migrate_del_blocker(s->migration_blocker);
error_free(s->migration_blocker);
qemu_vfree(s->log.hdr);
s->log.hdr = NULL;
vhdx_region_unregister_all(s);
}
static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVVHDXState *s = bs->opaque;
int ret = 0;
uint32_t i;
uint64_t signature;
Error *local_err = NULL;
s->bat = NULL;
s->first_visible_write = true;
qemu_co_mutex_init(&s->lock);
QLIST_INIT(&s->regions);
/* validate the file signature */
ret = bdrv_pread(bs->file, 0, &signature, sizeof(uint64_t));
if (ret < 0) {
goto fail;
}
if (memcmp(&signature, "vhdxfile", 8)) {
ret = -EINVAL;
goto fail;
}
/* This is used for any header updates, for the file_write_guid.
* The spec dictates that a new value should be used for the first
* header update */
vhdx_guid_generate(&s->session_guid);
vhdx_parse_header(bs, s, &local_err);
if (local_err != NULL) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
ret = vhdx_parse_log(bs, s, &s->log_replayed_on_open, errp);
if (ret < 0) {
goto fail;
}
ret = vhdx_open_region_tables(bs, s);
if (ret < 0) {
goto fail;
}
ret = vhdx_parse_metadata(bs, s);
if (ret < 0) {
goto fail;
}
s->block_size = s->params.block_size;
/* the VHDX spec dictates that virtual_disk_size is always a multiple of
* logical_sector_size */
bs->total_sectors = s->virtual_disk_size >> s->logical_sector_size_bits;
vhdx_calc_bat_entries(s);
s->bat_offset = s->bat_rt.file_offset;
if (s->bat_entries > s->bat_rt.length / sizeof(VHDXBatEntry)) {
/* BAT allocation is not large enough for all entries */
ret = -EINVAL;
goto fail;
}
/* s->bat is freed in vhdx_close() */
s->bat = qemu_blockalign(bs, s->bat_rt.length);
ret = bdrv_pread(bs->file, s->bat_offset, s->bat, s->bat_rt.length);
if (ret < 0) {
goto fail;
}
uint64_t payblocks = s->chunk_ratio;
/* endian convert, and verify populated BAT field file offsets against
* region table and log entries */
for (i = 0; i < s->bat_entries; i++) {
le64_to_cpus(&s->bat[i]);
if (payblocks--) {
/* payload bat entries */
if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) ==
PAYLOAD_BLOCK_FULLY_PRESENT) {
ret = vhdx_region_check(s, s->bat[i] & VHDX_BAT_FILE_OFF_MASK,
s->block_size);
if (ret < 0) {
goto fail;
}
}
} else {
payblocks = s->chunk_ratio;
/* Once differencing files are supported, verify sector bitmap
* blocks here */
}
}
if (flags & BDRV_O_RDWR) {
ret = vhdx_update_headers(bs, s, false, NULL);
if (ret < 0) {
goto fail;
}
}
/* TODO: differencing files */
/* Disable migration when VHDX images are used */
error_set(&s->migration_blocker,
QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
"vhdx", bs->device_name, "live migration");
migrate_add_blocker(s->migration_blocker);
return 0;
fail:
vhdx_close(bs);
return ret;
}
static int vhdx_reopen_prepare(BDRVReopenState *state,
BlockReopenQueue *queue, Error **errp)
{
return 0;
}
/*
* Perform sector to block offset translations, to get various
* sector and file offsets into the image. See VHDXSectorInfo
*/
static void vhdx_block_translate(BDRVVHDXState *s, int64_t sector_num,
int nb_sectors, VHDXSectorInfo *sinfo)
{
uint32_t block_offset;
sinfo->bat_idx = sector_num >> s->sectors_per_block_bits;
/* effectively a modulo - this gives us the offset into the block
* (in sector sizes) for our sector number */
block_offset = sector_num - (sinfo->bat_idx << s->sectors_per_block_bits);
/* the chunk ratio gives us the interleaving of the sector
* bitmaps, so we need to advance our page block index by the
* sector bitmaps entry number */
sinfo->bat_idx += sinfo->bat_idx >> s->chunk_ratio_bits;
/* the number of sectors we can read/write in this cycle */
sinfo->sectors_avail = s->sectors_per_block - block_offset;
sinfo->bytes_left = sinfo->sectors_avail << s->logical_sector_size_bits;
if (sinfo->sectors_avail > nb_sectors) {
sinfo->sectors_avail = nb_sectors;
}
sinfo->bytes_avail = sinfo->sectors_avail << s->logical_sector_size_bits;
sinfo->file_offset = s->bat[sinfo->bat_idx] & VHDX_BAT_FILE_OFF_MASK;
sinfo->block_offset = block_offset << s->logical_sector_size_bits;
/* The file offset must be past the header section, so must be > 0 */
if (sinfo->file_offset == 0) {
return;
}
/* block offset is the offset in vhdx logical sectors, in
* the payload data block. Convert that to a byte offset
* in the block, and add in the payload data block offset
* in the file, in bytes, to get the final read address */
sinfo->file_offset += sinfo->block_offset;
}
static int vhdx_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
BDRVVHDXState *s = bs->opaque;
bdi->cluster_size = s->block_size;
bdi->unallocated_blocks_are_zero =
(s->params.data_bits & VHDX_PARAMS_HAS_PARENT) == 0;
return 0;
}
static coroutine_fn int vhdx_co_readv(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
BDRVVHDXState *s = bs->opaque;
int ret = 0;
VHDXSectorInfo sinfo;
uint64_t bytes_done = 0;
QEMUIOVector hd_qiov;
qemu_iovec_init(&hd_qiov, qiov->niov);
qemu_co_mutex_lock(&s->lock);
while (nb_sectors > 0) {
/* We are a differencing file, so we need to inspect the sector bitmap
* to see if we have the data or not */
if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
/* not supported yet */
ret = -ENOTSUP;
goto exit;
} else {
vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
qemu_iovec_reset(&hd_qiov);
qemu_iovec_concat(&hd_qiov, qiov, bytes_done, sinfo.bytes_avail);
/* check the payload block state */
switch (s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK) {
case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
case PAYLOAD_BLOCK_UNDEFINED: /* fall through */
case PAYLOAD_BLOCK_UNMAPPED: /* fall through */
case PAYLOAD_BLOCK_ZERO:
/* return zero */
qemu_iovec_memset(&hd_qiov, 0, 0, sinfo.bytes_avail);
break;
case PAYLOAD_BLOCK_FULLY_PRESENT:
qemu_co_mutex_unlock(&s->lock);
ret = bdrv_co_readv(bs->file,
sinfo.file_offset >> BDRV_SECTOR_BITS,
sinfo.sectors_avail, &hd_qiov);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
goto exit;
}
break;
case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
/* we don't yet support difference files, fall through
* to error */
default:
ret = -EIO;
goto exit;
break;
}
nb_sectors -= sinfo.sectors_avail;
sector_num += sinfo.sectors_avail;
bytes_done += sinfo.bytes_avail;
}
}
ret = 0;
exit:
qemu_co_mutex_unlock(&s->lock);
qemu_iovec_destroy(&hd_qiov);
return ret;
}
/*
* Allocate a new payload block at the end of the file.
*
* Allocation will happen at 1MB alignment inside the file
*
* Returns the file offset start of the new payload block
*/
static int vhdx_allocate_block(BlockDriverState *bs, BDRVVHDXState *s,
uint64_t *new_offset)
{
*new_offset = bdrv_getlength(bs->file);
/* per the spec, the address for a block is in units of 1MB */
*new_offset = ROUND_UP(*new_offset, 1024 * 1024);
return bdrv_truncate(bs->file, *new_offset + s->block_size);
}
/*
* Update the BAT table entry with the new file offset, and the new entry
* state */
static void vhdx_update_bat_table_entry(BlockDriverState *bs, BDRVVHDXState *s,
VHDXSectorInfo *sinfo,
uint64_t *bat_entry_le,
uint64_t *bat_offset, int state)
{
/* The BAT entry is a uint64, with 44 bits for the file offset in units of
* 1MB, and 3 bits for the block state. */
s->bat[sinfo->bat_idx] = sinfo->file_offset;
s->bat[sinfo->bat_idx] |= state & VHDX_BAT_STATE_BIT_MASK;
*bat_entry_le = cpu_to_le64(s->bat[sinfo->bat_idx]);
*bat_offset = s->bat_offset + sinfo->bat_idx * sizeof(VHDXBatEntry);
}
/* Per the spec, on the first write of guest-visible data to the file the
* data write guid must be updated in the header */
int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s)
{
int ret = 0;
if (s->first_visible_write) {
s->first_visible_write = false;
ret = vhdx_update_headers(bs, s, true, NULL);
}
return ret;
}
static coroutine_fn int vhdx_co_writev(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
int ret = -ENOTSUP;
BDRVVHDXState *s = bs->opaque;
VHDXSectorInfo sinfo;
uint64_t bytes_done = 0;
uint64_t bat_entry = 0;
uint64_t bat_entry_offset = 0;
QEMUIOVector hd_qiov;
struct iovec iov1 = { 0 };
struct iovec iov2 = { 0 };
int sectors_to_write;
int bat_state;
uint64_t bat_prior_offset = 0;
bool bat_update = false;
qemu_iovec_init(&hd_qiov, qiov->niov);
qemu_co_mutex_lock(&s->lock);
ret = vhdx_user_visible_write(bs, s);
if (ret < 0) {
goto exit;
}
while (nb_sectors > 0) {
bool use_zero_buffers = false;
bat_update = false;
if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
/* not supported yet */
ret = -ENOTSUP;
goto exit;
} else {
vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
sectors_to_write = sinfo.sectors_avail;
qemu_iovec_reset(&hd_qiov);
/* check the payload block state */
bat_state = s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK;
switch (bat_state) {
case PAYLOAD_BLOCK_ZERO:
/* in this case, we need to preserve zero writes for
* data that is not part of this write, so we must pad
* the rest of the buffer to zeroes */
/* if we are on a posix system with ftruncate() that extends
* a file, then it is zero-filled for us. On Win32, the raw
* layer uses SetFilePointer and SetFileEnd, which does not
* zero fill AFAIK */
/* Queue another write of zero buffers if the underlying file
* does not zero-fill on file extension */
if (bdrv_has_zero_init(bs->file) == 0) {
use_zero_buffers = true;
/* zero fill the front, if any */
if (sinfo.block_offset) {
iov1.iov_len = sinfo.block_offset;
iov1.iov_base = qemu_blockalign(bs, iov1.iov_len);
memset(iov1.iov_base, 0, iov1.iov_len);
qemu_iovec_concat_iov(&hd_qiov, &iov1, 1, 0,
sinfo.block_offset);
sectors_to_write += iov1.iov_len >> BDRV_SECTOR_BITS;
}
/* our actual data */
qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
sinfo.bytes_avail);
/* zero fill the back, if any */
if ((sinfo.bytes_avail - sinfo.block_offset) <
s->block_size) {
iov2.iov_len = s->block_size -
(sinfo.bytes_avail + sinfo.block_offset);
iov2.iov_base = qemu_blockalign(bs, iov2.iov_len);
memset(iov2.iov_base, 0, iov2.iov_len);
qemu_iovec_concat_iov(&hd_qiov, &iov2, 1, 0,
sinfo.block_offset);
sectors_to_write += iov2.iov_len >> BDRV_SECTOR_BITS;
}
}
/* fall through */
case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
case PAYLOAD_BLOCK_UNMAPPED: /* fall through */
case PAYLOAD_BLOCK_UNDEFINED: /* fall through */
bat_prior_offset = sinfo.file_offset;
ret = vhdx_allocate_block(bs, s, &sinfo.file_offset);
if (ret < 0) {
goto exit;
}
/* once we support differencing files, this may also be
* partially present */
/* update block state to the newly specified state */
vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
&bat_entry_offset,
PAYLOAD_BLOCK_FULLY_PRESENT);
bat_update = true;
/* since we just allocated a block, file_offset is the
* beginning of the payload block. It needs to be the
* write address, which includes the offset into the block */
if (!use_zero_buffers) {
sinfo.file_offset += sinfo.block_offset;
}
/* fall through */
case PAYLOAD_BLOCK_FULLY_PRESENT:
/* if the file offset address is in the header zone,
* there is a problem */
if (sinfo.file_offset < (1024 * 1024)) {
ret = -EFAULT;
goto error_bat_restore;
}
if (!use_zero_buffers) {
qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
sinfo.bytes_avail);
}
/* block exists, so we can just overwrite it */
qemu_co_mutex_unlock(&s->lock);
ret = bdrv_co_writev(bs->file,
sinfo.file_offset >> BDRV_SECTOR_BITS,
sectors_to_write, &hd_qiov);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
goto error_bat_restore;
}
break;
case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
/* we don't yet support difference files, fall through
* to error */
default:
ret = -EIO;
goto exit;
break;
}
if (bat_update) {
/* this will update the BAT entry into the log journal, and
* then flush the log journal out to disk */
ret = vhdx_log_write_and_flush(bs, s, &bat_entry,
sizeof(VHDXBatEntry),
bat_entry_offset);
if (ret < 0) {
goto exit;
}
}
nb_sectors -= sinfo.sectors_avail;
sector_num += sinfo.sectors_avail;
bytes_done += sinfo.bytes_avail;
}
}
goto exit;
error_bat_restore:
if (bat_update) {
/* keep metadata in sync, and restore the bat entry state
* if error. */
sinfo.file_offset = bat_prior_offset;
vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
&bat_entry_offset, bat_state);
}
exit:
qemu_vfree(iov1.iov_base);
qemu_vfree(iov2.iov_base);
qemu_co_mutex_unlock(&s->lock);
qemu_iovec_destroy(&hd_qiov);
return ret;
}
/*
* Create VHDX Headers
*
* There are 2 headers, and the highest sequence number will represent
* the active header
*/
static int vhdx_create_new_headers(BlockDriverState *bs, uint64_t image_size,
uint32_t log_size)
{
int ret = 0;
VHDXHeader *hdr = NULL;
hdr = g_malloc0(sizeof(VHDXHeader));
hdr->signature = VHDX_HEADER_SIGNATURE;
hdr->sequence_number = g_random_int();
hdr->log_version = 0;
hdr->version = 1;
hdr->log_length = log_size;
hdr->log_offset = VHDX_HEADER_SECTION_END;
vhdx_guid_generate(&hdr->file_write_guid);
vhdx_guid_generate(&hdr->data_write_guid);
ret = vhdx_write_header(bs, hdr, VHDX_HEADER1_OFFSET, false);
if (ret < 0) {
goto exit;
}
hdr->sequence_number++;
ret = vhdx_write_header(bs, hdr, VHDX_HEADER2_OFFSET, false);
if (ret < 0) {
goto exit;
}
exit:
g_free(hdr);
return ret;
}
/*
* Create the Metadata entries.
*
* For more details on the entries, see section 3.5 (pg 29) in the
* VHDX 1.00 specification.
*
* We support 5 metadata entries (all required by spec):
* File Parameters,
* Virtual Disk Size,
* Page 83 Data,
* Logical Sector Size,
* Physical Sector Size
*
* The first 64KB of the Metadata section is reserved for the metadata
* header and entries; beyond that, the metadata items themselves reside.
*/
static int vhdx_create_new_metadata(BlockDriverState *bs,
uint64_t image_size,
uint32_t block_size,
uint32_t sector_size,
uint64_t metadata_offset,
VHDXImageType type)
{
int ret = 0;
uint32_t offset = 0;
void *buffer = NULL;
void *entry_buffer;
VHDXMetadataTableHeader *md_table;;
VHDXMetadataTableEntry *md_table_entry;
/* Metadata entries */
VHDXFileParameters *mt_file_params;
VHDXVirtualDiskSize *mt_virtual_size;
VHDXPage83Data *mt_page83;
VHDXVirtualDiskLogicalSectorSize *mt_log_sector_size;
VHDXVirtualDiskPhysicalSectorSize *mt_phys_sector_size;
entry_buffer = g_malloc0(sizeof(VHDXFileParameters) +
sizeof(VHDXVirtualDiskSize) +
sizeof(VHDXPage83Data) +
sizeof(VHDXVirtualDiskLogicalSectorSize) +
sizeof(VHDXVirtualDiskPhysicalSectorSize));
mt_file_params = entry_buffer;
offset += sizeof(VHDXFileParameters);
mt_virtual_size = entry_buffer + offset;
offset += sizeof(VHDXVirtualDiskSize);
mt_page83 = entry_buffer + offset;
offset += sizeof(VHDXPage83Data);
mt_log_sector_size = entry_buffer + offset;
offset += sizeof(VHDXVirtualDiskLogicalSectorSize);
mt_phys_sector_size = entry_buffer + offset;
mt_file_params->block_size = cpu_to_le32(block_size);
if (type == VHDX_TYPE_FIXED) {
mt_file_params->data_bits |= VHDX_PARAMS_LEAVE_BLOCKS_ALLOCED;
cpu_to_le32s(&mt_file_params->data_bits);
}
vhdx_guid_generate(&mt_page83->page_83_data);
cpu_to_leguids(&mt_page83->page_83_data);
mt_virtual_size->virtual_disk_size = cpu_to_le64(image_size);
mt_log_sector_size->logical_sector_size = cpu_to_le32(sector_size);
mt_phys_sector_size->physical_sector_size = cpu_to_le32(sector_size);
buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
md_table = buffer;
md_table->signature = VHDX_METADATA_SIGNATURE;
md_table->entry_count = 5;
vhdx_metadata_header_le_export(md_table);
/* This will reference beyond the reserved table portion */
offset = 64 * KiB;
md_table_entry = buffer + sizeof(VHDXMetadataTableHeader);
md_table_entry[0].item_id = file_param_guid;
md_table_entry[0].offset = offset;
md_table_entry[0].length = sizeof(VHDXFileParameters);
md_table_entry[0].data_bits |= VHDX_META_FLAGS_IS_REQUIRED;
offset += md_table_entry[0].length;
vhdx_metadata_entry_le_export(&md_table_entry[0]);
md_table_entry[1].item_id = virtual_size_guid;
md_table_entry[1].offset = offset;
md_table_entry[1].length = sizeof(VHDXVirtualDiskSize);
md_table_entry[1].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
VHDX_META_FLAGS_IS_VIRTUAL_DISK;
offset += md_table_entry[1].length;
vhdx_metadata_entry_le_export(&md_table_entry[1]);
md_table_entry[2].item_id = page83_guid;
md_table_entry[2].offset = offset;
md_table_entry[2].length = sizeof(VHDXPage83Data);
md_table_entry[2].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
VHDX_META_FLAGS_IS_VIRTUAL_DISK;
offset += md_table_entry[2].length;
vhdx_metadata_entry_le_export(&md_table_entry[2]);
md_table_entry[3].item_id = logical_sector_guid;
md_table_entry[3].offset = offset;
md_table_entry[3].length = sizeof(VHDXVirtualDiskLogicalSectorSize);
md_table_entry[3].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
VHDX_META_FLAGS_IS_VIRTUAL_DISK;
offset += md_table_entry[3].length;
vhdx_metadata_entry_le_export(&md_table_entry[3]);
md_table_entry[4].item_id = phys_sector_guid;
md_table_entry[4].offset = offset;
md_table_entry[4].length = sizeof(VHDXVirtualDiskPhysicalSectorSize);
md_table_entry[4].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
VHDX_META_FLAGS_IS_VIRTUAL_DISK;
vhdx_metadata_entry_le_export(&md_table_entry[4]);
ret = bdrv_pwrite(bs, metadata_offset, buffer, VHDX_HEADER_BLOCK_SIZE);
if (ret < 0) {
goto exit;
}
ret = bdrv_pwrite(bs, metadata_offset + (64 * KiB), entry_buffer,
VHDX_HEADER_BLOCK_SIZE);
if (ret < 0) {
goto exit;
}
exit:
g_free(buffer);
g_free(entry_buffer);
return ret;
}
/* This create the actual BAT itself. We currently only support
* 'Dynamic' and 'Fixed' image types.
*
* Dynamic images: default state of the BAT is all zeroes.
*
* Fixed images: default state of the BAT is fully populated, with
* file offsets and state PAYLOAD_BLOCK_FULLY_PRESENT.
*/
static int vhdx_create_bat(BlockDriverState *bs, BDRVVHDXState *s,
uint64_t image_size, VHDXImageType type,
bool use_zero_blocks, VHDXRegionTableEntry *rt_bat)
{
int ret = 0;
uint64_t data_file_offset;
uint64_t total_sectors = 0;
uint64_t sector_num = 0;
uint64_t unused;
int block_state;
VHDXSectorInfo sinfo;
assert(s->bat == NULL);
/* this gives a data start after BAT/bitmap entries, and well
* past any metadata entries (with a 4 MB buffer for future
* expansion */
data_file_offset = rt_bat->file_offset + rt_bat->length + 5 * MiB;
total_sectors = image_size >> s->logical_sector_size_bits;
if (type == VHDX_TYPE_DYNAMIC) {
/* All zeroes, so we can just extend the file - the end of the BAT
* is the furthest thing we have written yet */
ret = bdrv_truncate(bs, data_file_offset);
if (ret < 0) {
goto exit;
}
} else if (type == VHDX_TYPE_FIXED) {
ret = bdrv_truncate(bs, data_file_offset + image_size);
if (ret < 0) {
goto exit;
}
} else {
ret = -ENOTSUP;
goto exit;
}
if (type == VHDX_TYPE_FIXED ||
use_zero_blocks ||
bdrv_has_zero_init(bs) == 0) {
/* for a fixed file, the default BAT entry is not zero */
s->bat = g_malloc0(rt_bat->length);
block_state = type == VHDX_TYPE_FIXED ? PAYLOAD_BLOCK_FULLY_PRESENT :
PAYLOAD_BLOCK_NOT_PRESENT;
block_state = use_zero_blocks ? PAYLOAD_BLOCK_ZERO : block_state;
/* fill the BAT by emulating sector writes of sectors_per_block size */
while (sector_num < total_sectors) {
vhdx_block_translate(s, sector_num, s->sectors_per_block, &sinfo);
sinfo.file_offset = data_file_offset +
(sector_num << s->logical_sector_size_bits);
sinfo.file_offset = ROUND_UP(sinfo.file_offset, MiB);
vhdx_update_bat_table_entry(bs, s, &sinfo, &unused, &unused,
block_state);
cpu_to_le64s(&s->bat[sinfo.bat_idx]);
sector_num += s->sectors_per_block;
}
ret = bdrv_pwrite(bs, rt_bat->file_offset, s->bat, rt_bat->length);
if (ret < 0) {
goto exit;
}
}
exit:
g_free(s->bat);
return ret;
}
/* Creates the region table header, and region table entries.
* There are 2 supported region table entries: BAT, and Metadata/
*
* As the calculations for the BAT region table are also needed
* to create the BAT itself, we will also cause the BAT to be
* created.
*/
static int vhdx_create_new_region_table(BlockDriverState *bs,
uint64_t image_size,
uint32_t block_size,
uint32_t sector_size,
uint32_t log_size,
bool use_zero_blocks,
VHDXImageType type,
uint64_t *metadata_offset)
{
int ret = 0;
uint32_t offset = 0;
void *buffer = NULL;
BDRVVHDXState *s = NULL;
VHDXRegionTableHeader *region_table;
VHDXRegionTableEntry *rt_bat;
VHDXRegionTableEntry *rt_metadata;
assert(metadata_offset != NULL);
/* Populate enough of the BDRVVHDXState to be able to use the
* pre-existing BAT calculation, translation, and update functions */
s = g_malloc0(sizeof(BDRVVHDXState));
s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
(uint64_t) sector_size / (uint64_t) block_size;
s->sectors_per_block = block_size / sector_size;
s->virtual_disk_size = image_size;
s->block_size = block_size;
s->logical_sector_size = sector_size;
vhdx_set_shift_bits(s);
vhdx_calc_bat_entries(s);
/* At this point the VHDX state is populated enough for creation */
/* a single buffer is used so we can calculate the checksum over the
* entire 64KB block */
buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
region_table = buffer;
offset += sizeof(VHDXRegionTableHeader);
rt_bat = buffer + offset;
offset += sizeof(VHDXRegionTableEntry);
rt_metadata = buffer + offset;
region_table->signature = VHDX_REGION_SIGNATURE;
region_table->entry_count = 2; /* BAT and Metadata */
rt_bat->guid = bat_guid;
rt_bat->length = ROUND_UP(s->bat_entries * sizeof(VHDXBatEntry), MiB);
rt_bat->file_offset = ROUND_UP(VHDX_HEADER_SECTION_END + log_size, MiB);
s->bat_offset = rt_bat->file_offset;
rt_metadata->guid = metadata_guid;
rt_metadata->file_offset = ROUND_UP(rt_bat->file_offset + rt_bat->length,
MiB);
rt_metadata->length = 1 * MiB; /* min size, and more than enough */
*metadata_offset = rt_metadata->file_offset;
vhdx_update_checksum(buffer, VHDX_HEADER_BLOCK_SIZE,
offsetof(VHDXRegionTableHeader, checksum));
/* The region table gives us the data we need to create the BAT,
* so do that now */
ret = vhdx_create_bat(bs, s, image_size, type, use_zero_blocks, rt_bat);
/* Now write out the region headers to disk */
vhdx_region_header_le_export(region_table);
vhdx_region_entry_le_export(rt_bat);
vhdx_region_entry_le_export(rt_metadata);
ret = bdrv_pwrite(bs, VHDX_REGION_TABLE_OFFSET, buffer,
VHDX_HEADER_BLOCK_SIZE);
if (ret < 0) {
goto exit;
}
ret = bdrv_pwrite(bs, VHDX_REGION_TABLE2_OFFSET, buffer,
VHDX_HEADER_BLOCK_SIZE);
if (ret < 0) {
goto exit;
}
exit:
g_free(s);
g_free(buffer);
return ret;
}
/* We need to create the following elements:
*
* .-----------------------------------------------------------------.
* | (A) | (B) | (C) | (D) | (E) |
* | File ID | Header1 | Header 2 | Region Tbl 1 | Region Tbl 2 |
* | | | | | |
* .-----------------------------------------------------------------.
* 0 64KB 128KB 192KB 256KB 320KB
*
*
* .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
* | (F) | (G) | (H) | |
* | Journal Log | BAT / Bitmap | Metadata | .... data ...... |
* | | | | |
* .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
* 1MB
*/
static int vhdx_create(const char *filename, QemuOpts *opts, Error **errp)
{
int ret = 0;
uint64_t image_size = (uint64_t) 2 * GiB;
uint32_t log_size = 1 * MiB;
uint32_t block_size = 0;
uint64_t signature;
uint64_t metadata_offset;
bool use_zero_blocks = false;
gunichar2 *creator = NULL;
glong creator_items;
BlockDriverState *bs;
char *type = NULL;
VHDXImageType image_type;
Error *local_err = NULL;
image_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
log_size = qemu_opt_get_size_del(opts, VHDX_BLOCK_OPT_LOG_SIZE, 0);
block_size = qemu_opt_get_size_del(opts, VHDX_BLOCK_OPT_BLOCK_SIZE, 0);
type = qemu_opt_get_del(opts, BLOCK_OPT_SUBFMT);
use_zero_blocks = qemu_opt_get_bool_del(opts, VHDX_BLOCK_OPT_ZERO, false);
if (image_size > VHDX_MAX_IMAGE_SIZE) {
error_setg_errno(errp, EINVAL, "Image size too large; max of 64TB");
ret = -EINVAL;
goto exit;
}
if (type == NULL) {
type = g_strdup("dynamic");
}
if (!strcmp(type, "dynamic")) {
image_type = VHDX_TYPE_DYNAMIC;
} else if (!strcmp(type, "fixed")) {
image_type = VHDX_TYPE_FIXED;
} else if (!strcmp(type, "differencing")) {
error_setg_errno(errp, ENOTSUP,
"Differencing files not yet supported");
ret = -ENOTSUP;
goto exit;
} else {
ret = -EINVAL;
goto exit;
}
/* These are pretty arbitrary, and mainly designed to keep the BAT
* size reasonable to load into RAM */
if (block_size == 0) {
if (image_size > 32 * TiB) {
block_size = 64 * MiB;
} else if (image_size > (uint64_t) 100 * GiB) {
block_size = 32 * MiB;
} else if (image_size > 1 * GiB) {
block_size = 16 * MiB;
} else {
block_size = 8 * MiB;
}
}
/* make the log size close to what was specified, but must be
* min 1MB, and multiple of 1MB */
log_size = ROUND_UP(log_size, MiB);
block_size = ROUND_UP(block_size, MiB);
block_size = block_size > VHDX_BLOCK_SIZE_MAX ? VHDX_BLOCK_SIZE_MAX :
block_size;
ret = bdrv_create_file(filename, opts, &local_err);
if (ret < 0) {
error_propagate(errp, local_err);
goto exit;
}
bs = NULL;
ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
NULL, &local_err);
if (ret < 0) {
error_propagate(errp, local_err);
goto exit;
}
/* Create (A) */
/* The creator field is optional, but may be useful for
* debugging / diagnostics */
creator = g_utf8_to_utf16("QEMU v" QEMU_VERSION, -1, NULL,
&creator_items, NULL);
signature = cpu_to_le64(VHDX_FILE_SIGNATURE);
ret = bdrv_pwrite(bs, VHDX_FILE_ID_OFFSET, &signature, sizeof(signature));
if (ret < 0) {
goto delete_and_exit;
}
if (creator) {
ret = bdrv_pwrite(bs, VHDX_FILE_ID_OFFSET + sizeof(signature),
creator, creator_items * sizeof(gunichar2));
if (ret < 0) {
goto delete_and_exit;
}
}
/* Creates (B),(C) */
ret = vhdx_create_new_headers(bs, image_size, log_size);
if (ret < 0) {
goto delete_and_exit;
}
/* Creates (D),(E),(G) explicitly. (F) created as by-product */
ret = vhdx_create_new_region_table(bs, image_size, block_size, 512,
log_size, use_zero_blocks, image_type,
&metadata_offset);
if (ret < 0) {
goto delete_and_exit;
}
/* Creates (H) */
ret = vhdx_create_new_metadata(bs, image_size, block_size, 512,
metadata_offset, image_type);
if (ret < 0) {
goto delete_and_exit;
}
delete_and_exit:
bdrv_unref(bs);
exit:
g_free(type);
g_free(creator);
return ret;
}
/* If opened r/w, the VHDX driver will automatically replay the log,
* if one is present, inside the vhdx_open() call.
*
* If qemu-img check -r all is called, the image is automatically opened
* r/w and any log has already been replayed, so there is nothing (currently)
* for us to do here
*/
static int vhdx_check(BlockDriverState *bs, BdrvCheckResult *result,
BdrvCheckMode fix)
{
BDRVVHDXState *s = bs->opaque;
if (s->log_replayed_on_open) {
result->corruptions_fixed++;
}
return 0;
}
static QemuOptsList vhdx_create_opts = {
.name = "vhdx-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(vhdx_create_opts.head),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size; max of 64TB."
},
{
.name = VHDX_BLOCK_OPT_LOG_SIZE,
.type = QEMU_OPT_SIZE,
.def_value_str = stringify(DEFAULT_LOG_SIZE),
.help = "Log size; min 1MB."
},
{
.name = VHDX_BLOCK_OPT_BLOCK_SIZE,
.type = QEMU_OPT_SIZE,
.def_value_str = stringify(0),
.help = "Block Size; min 1MB, max 256MB. " \
"0 means auto-calculate based on image size."
},
{
.name = BLOCK_OPT_SUBFMT,
.type = QEMU_OPT_STRING,
.help = "VHDX format type, can be either 'dynamic' or 'fixed'. "\
"Default is 'dynamic'."
},
{
.name = VHDX_BLOCK_OPT_ZERO,
.type = QEMU_OPT_BOOL,
.help = "Force use of payload blocks of type 'ZERO'. Non-standard."
},
{ NULL }
}
};
static BlockDriver bdrv_vhdx = {
.format_name = "vhdx",
.instance_size = sizeof(BDRVVHDXState),
.bdrv_probe = vhdx_probe,
.bdrv_open = vhdx_open,
.bdrv_close = vhdx_close,
.bdrv_reopen_prepare = vhdx_reopen_prepare,
.bdrv_co_readv = vhdx_co_readv,
.bdrv_co_writev = vhdx_co_writev,
.bdrv_create = vhdx_create,
.bdrv_get_info = vhdx_get_info,
.bdrv_check = vhdx_check,
.create_opts = &vhdx_create_opts,
};
static void bdrv_vhdx_init(void)
{
bdrv_register(&bdrv_vhdx);
}
block_init(bdrv_vhdx_init);
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