qemu/block/vhdx.c
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   1/*
   2 * Block driver for Hyper-V VHDX Images
   3 *
   4 * Copyright (c) 2013 Red Hat, Inc.,
   5 *
   6 * Authors:
   7 *  Jeff Cody <jcody@redhat.com>
   8 *
   9 *  This is based on the "VHDX Format Specification v1.00", published 8/25/2012
  10 *  by Microsoft:
  11 *      https://www.microsoft.com/en-us/download/details.aspx?id=34750
  12 *
  13 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
  14 * See the COPYING.LIB file in the top-level directory.
  15 *
  16 */
  17
  18#include "qemu/osdep.h"
  19#include "qapi/error.h"
  20#include "qemu-common.h"
  21#include "block/block_int.h"
  22#include "sysemu/block-backend.h"
  23#include "qemu/module.h"
  24#include "qemu/crc32c.h"
  25#include "block/vhdx.h"
  26#include "migration/migration.h"
  27
  28#include <uuid/uuid.h>
  29#include <glib.h>
  30
  31/* Options for VHDX creation */
  32
  33#define VHDX_BLOCK_OPT_LOG_SIZE   "log_size"
  34#define VHDX_BLOCK_OPT_BLOCK_SIZE "block_size"
  35#define VHDX_BLOCK_OPT_ZERO "block_state_zero"
  36
  37typedef enum VHDXImageType {
  38    VHDX_TYPE_DYNAMIC = 0,
  39    VHDX_TYPE_FIXED,
  40    VHDX_TYPE_DIFFERENCING,   /* Currently unsupported */
  41} VHDXImageType;
  42
  43/* Several metadata and region table data entries are identified by
  44 * guids in  a MS-specific GUID format. */
  45
  46
  47/* ------- Known Region Table GUIDs ---------------------- */
  48static const MSGUID bat_guid =      { .data1 = 0x2dc27766,
  49                                      .data2 = 0xf623,
  50                                      .data3 = 0x4200,
  51                                      .data4 = { 0x9d, 0x64, 0x11, 0x5e,
  52                                                 0x9b, 0xfd, 0x4a, 0x08} };
  53
  54static const MSGUID metadata_guid = { .data1 = 0x8b7ca206,
  55                                      .data2 = 0x4790,
  56                                      .data3 = 0x4b9a,
  57                                      .data4 = { 0xb8, 0xfe, 0x57, 0x5f,
  58                                                 0x05, 0x0f, 0x88, 0x6e} };
  59
  60
  61
  62/* ------- Known Metadata Entry GUIDs ---------------------- */
  63static const MSGUID file_param_guid =   { .data1 = 0xcaa16737,
  64                                          .data2 = 0xfa36,
  65                                          .data3 = 0x4d43,
  66                                          .data4 = { 0xb3, 0xb6, 0x33, 0xf0,
  67                                                     0xaa, 0x44, 0xe7, 0x6b} };
  68
  69static const MSGUID virtual_size_guid = { .data1 = 0x2FA54224,
  70                                          .data2 = 0xcd1b,
  71                                          .data3 = 0x4876,
  72                                          .data4 = { 0xb2, 0x11, 0x5d, 0xbe,
  73                                                     0xd8, 0x3b, 0xf4, 0xb8} };
  74
  75static const MSGUID page83_guid =       { .data1 = 0xbeca12ab,
  76                                          .data2 = 0xb2e6,
  77                                          .data3 = 0x4523,
  78                                          .data4 = { 0x93, 0xef, 0xc3, 0x09,
  79                                                     0xe0, 0x00, 0xc7, 0x46} };
  80
  81
  82static const MSGUID phys_sector_guid =  { .data1 = 0xcda348c7,
  83                                          .data2 = 0x445d,
  84                                          .data3 = 0x4471,
  85                                          .data4 = { 0x9c, 0xc9, 0xe9, 0x88,
  86                                                     0x52, 0x51, 0xc5, 0x56} };
  87
  88static const MSGUID parent_locator_guid = { .data1 = 0xa8d35f2d,
  89                                            .data2 = 0xb30b,
  90                                            .data3 = 0x454d,
  91                                            .data4 = { 0xab, 0xf7, 0xd3,
  92                                                       0xd8, 0x48, 0x34,
  93                                                       0xab, 0x0c} };
  94
  95static const MSGUID logical_sector_guid = { .data1 = 0x8141bf1d,
  96                                            .data2 = 0xa96f,
  97                                            .data3 = 0x4709,
  98                                            .data4 = { 0xba, 0x47, 0xf2,
  99                                                       0x33, 0xa8, 0xfa,
 100                                                       0xab, 0x5f} };
 101
 102/* Each parent type must have a valid GUID; this is for parent images
 103 * of type 'VHDX'.  If we were to allow e.g. a QCOW2 parent, we would
 104 * need to make up our own QCOW2 GUID type */
 105static const MSGUID parent_vhdx_guid __attribute__((unused))
 106                                     = { .data1 = 0xb04aefb7,
 107                                         .data2 = 0xd19e,
 108                                         .data3 = 0x4a81,
 109                                         .data4 = { 0xb7, 0x89, 0x25, 0xb8,
 110                                                    0xe9, 0x44, 0x59, 0x13} };
 111
 112
 113#define META_FILE_PARAMETER_PRESENT      0x01
 114#define META_VIRTUAL_DISK_SIZE_PRESENT   0x02
 115#define META_PAGE_83_PRESENT             0x04
 116#define META_LOGICAL_SECTOR_SIZE_PRESENT 0x08
 117#define META_PHYS_SECTOR_SIZE_PRESENT    0x10
 118#define META_PARENT_LOCATOR_PRESENT      0x20
 119
 120#define META_ALL_PRESENT    \
 121    (META_FILE_PARAMETER_PRESENT | META_VIRTUAL_DISK_SIZE_PRESENT | \
 122     META_PAGE_83_PRESENT | META_LOGICAL_SECTOR_SIZE_PRESENT | \
 123     META_PHYS_SECTOR_SIZE_PRESENT)
 124
 125
 126typedef struct VHDXSectorInfo {
 127    uint32_t bat_idx;       /* BAT entry index */
 128    uint32_t sectors_avail; /* sectors available in payload block */
 129    uint32_t bytes_left;    /* bytes left in the block after data to r/w */
 130    uint32_t bytes_avail;   /* bytes available in payload block */
 131    uint64_t file_offset;   /* absolute offset in bytes, in file */
 132    uint64_t block_offset;  /* block offset, in bytes */
 133} VHDXSectorInfo;
 134
 135/* Calculates new checksum.
 136 *
 137 * Zero is substituted during crc calculation for the original crc field
 138 * crc_offset: byte offset in buf of the buffer crc
 139 * buf: buffer pointer
 140 * size: size of buffer (must be > crc_offset+4)
 141 *
 142 * Note: The buffer should have all multi-byte data in little-endian format,
 143 *       and the resulting checksum is in little endian format.
 144 */
 145uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset)
 146{
 147    uint32_t crc;
 148
 149    assert(buf != NULL);
 150    assert(size > (crc_offset + sizeof(crc)));
 151
 152    memset(buf + crc_offset, 0, sizeof(crc));
 153    crc =  crc32c(0xffffffff, buf, size);
 154    cpu_to_le32s(&crc);
 155    memcpy(buf + crc_offset, &crc, sizeof(crc));
 156
 157    return crc;
 158}
 159
 160uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
 161                            int crc_offset)
 162{
 163    uint32_t crc_new;
 164    uint32_t crc_orig;
 165    assert(buf != NULL);
 166
 167    if (crc_offset > 0) {
 168        memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
 169        memset(buf + crc_offset, 0, sizeof(crc_orig));
 170    }
 171
 172    crc_new = crc32c(crc, buf, size);
 173    if (crc_offset > 0) {
 174        memcpy(buf + crc_offset, &crc_orig, sizeof(crc_orig));
 175    }
 176
 177    return crc_new;
 178}
 179
 180/* Validates the checksum of the buffer, with an in-place CRC.
 181 *
 182 * Zero is substituted during crc calculation for the original crc field,
 183 * and the crc field is restored afterwards.  But the buffer will be modifed
 184 * during the calculation, so this may not be not suitable for multi-threaded
 185 * use.
 186 *
 187 * crc_offset: byte offset in buf of the buffer crc
 188 * buf: buffer pointer
 189 * size: size of buffer (must be > crc_offset+4)
 190 *
 191 * returns true if checksum is valid, false otherwise
 192 */
 193bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset)
 194{
 195    uint32_t crc_orig;
 196    uint32_t crc;
 197
 198    assert(buf != NULL);
 199    assert(size > (crc_offset + 4));
 200
 201    memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
 202    crc_orig = le32_to_cpu(crc_orig);
 203
 204    crc = vhdx_checksum_calc(0xffffffff, buf, size, crc_offset);
 205
 206    return crc == crc_orig;
 207}
 208
 209
 210/*
 211 * This generates a UUID that is compliant with the MS GUIDs used
 212 * in the VHDX spec (and elsewhere).
 213 */
 214void vhdx_guid_generate(MSGUID *guid)
 215{
 216    uuid_t uuid;
 217    assert(guid != NULL);
 218
 219    uuid_generate(uuid);
 220    memcpy(guid, uuid, sizeof(MSGUID));
 221}
 222
 223/* Check for region overlaps inside the VHDX image */
 224static int vhdx_region_check(BDRVVHDXState *s, uint64_t start, uint64_t length)
 225{
 226    int ret = 0;
 227    uint64_t end;
 228    VHDXRegionEntry *r;
 229
 230    end = start + length;
 231    QLIST_FOREACH(r, &s->regions, entries) {
 232        if (!((start >= r->end) || (end <= r->start))) {
 233            ret = -EINVAL;
 234            goto exit;
 235        }
 236    }
 237
 238exit:
 239    return ret;
 240}
 241
 242/* Register a region for future checks */
 243static void vhdx_region_register(BDRVVHDXState *s,
 244                                 uint64_t start, uint64_t length)
 245{
 246    VHDXRegionEntry *r;
 247
 248    r = g_malloc0(sizeof(*r));
 249
 250    r->start = start;
 251    r->end = start + length;
 252
 253    QLIST_INSERT_HEAD(&s->regions, r, entries);
 254}
 255
 256/* Free all registered regions */
 257static void vhdx_region_unregister_all(BDRVVHDXState *s)
 258{
 259    VHDXRegionEntry *r, *r_next;
 260
 261    QLIST_FOREACH_SAFE(r, &s->regions, entries, r_next) {
 262        QLIST_REMOVE(r, entries);
 263        g_free(r);
 264    }
 265}
 266
 267static void vhdx_set_shift_bits(BDRVVHDXState *s)
 268{
 269    s->logical_sector_size_bits = ctz32(s->logical_sector_size);
 270    s->sectors_per_block_bits =   ctz32(s->sectors_per_block);
 271    s->chunk_ratio_bits =         ctz64(s->chunk_ratio);
 272    s->block_size_bits =          ctz32(s->block_size);
 273}
 274
 275/*
 276 * Per the MS VHDX Specification, for every VHDX file:
 277 *      - The header section is fixed size - 1 MB
 278 *      - The header section is always the first "object"
 279 *      - The first 64KB of the header is the File Identifier
 280 *      - The first uint64 (8 bytes) is the VHDX Signature ("vhdxfile")
 281 *      - The following 512 bytes constitute a UTF-16 string identifiying the
 282 *        software that created the file, and is optional and diagnostic only.
 283 *
 284 *  Therefore, we probe by looking for the vhdxfile signature "vhdxfile"
 285 */
 286static int vhdx_probe(const uint8_t *buf, int buf_size, const char *filename)
 287{
 288    if (buf_size >= 8 && !memcmp(buf, "vhdxfile", 8)) {
 289        return 100;
 290    }
 291    return 0;
 292}
 293
 294/*
 295 * Writes the header to the specified offset.
 296 *
 297 * This will optionally read in buffer data from disk (otherwise zero-fill),
 298 * and then update the header checksum.  Header is converted to proper
 299 * endianness before being written to the specified file offset
 300 */
 301static int vhdx_write_header(BlockDriverState *bs_file, VHDXHeader *hdr,
 302                             uint64_t offset, bool read)
 303{
 304    uint8_t *buffer = NULL;
 305    int ret;
 306    VHDXHeader *header_le;
 307
 308    assert(bs_file != NULL);
 309    assert(hdr != NULL);
 310
 311    /* the header checksum is not over just the packed size of VHDXHeader,
 312     * but rather over the entire 'reserved' range for the header, which is
 313     * 4KB (VHDX_HEADER_SIZE). */
 314
 315    buffer = qemu_blockalign(bs_file, VHDX_HEADER_SIZE);
 316    if (read) {
 317        /* if true, we can't assume the extra reserved bytes are 0 */
 318        ret = bdrv_pread(bs_file, offset, buffer, VHDX_HEADER_SIZE);
 319        if (ret < 0) {
 320            goto exit;
 321        }
 322    } else {
 323        memset(buffer, 0, VHDX_HEADER_SIZE);
 324    }
 325
 326    /* overwrite the actual VHDXHeader portion */
 327    header_le = (VHDXHeader *)buffer;
 328    memcpy(header_le, hdr, sizeof(VHDXHeader));
 329    vhdx_header_le_export(hdr, header_le);
 330    vhdx_update_checksum(buffer, VHDX_HEADER_SIZE,
 331                         offsetof(VHDXHeader, checksum));
 332    ret = bdrv_pwrite_sync(bs_file, offset, header_le, sizeof(VHDXHeader));
 333
 334exit:
 335    qemu_vfree(buffer);
 336    return ret;
 337}
 338
 339/* Update the VHDX headers
 340 *
 341 * This follows the VHDX spec procedures for header updates.
 342 *
 343 *  - non-current header is updated with largest sequence number
 344 */
 345static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s,
 346                              bool generate_data_write_guid, MSGUID *log_guid)
 347{
 348    int ret = 0;
 349    int hdr_idx = 0;
 350    uint64_t header_offset = VHDX_HEADER1_OFFSET;
 351
 352    VHDXHeader *active_header;
 353    VHDXHeader *inactive_header;
 354
 355    /* operate on the non-current header */
 356    if (s->curr_header == 0) {
 357        hdr_idx = 1;
 358        header_offset = VHDX_HEADER2_OFFSET;
 359    }
 360
 361    active_header   = s->headers[s->curr_header];
 362    inactive_header = s->headers[hdr_idx];
 363
 364    inactive_header->sequence_number = active_header->sequence_number + 1;
 365
 366    /* a new file guid must be generated before any file write, including
 367     * headers */
 368    inactive_header->file_write_guid = s->session_guid;
 369
 370    /* a new data guid only needs to be generated before any guest-visible
 371     * writes (i.e. something observable via virtual disk read) */
 372    if (generate_data_write_guid) {
 373        vhdx_guid_generate(&inactive_header->data_write_guid);
 374    }
 375
 376    /* update the log guid if present */
 377    if (log_guid) {
 378        inactive_header->log_guid = *log_guid;
 379    }
 380
 381    ret = vhdx_write_header(bs->file->bs, inactive_header, header_offset, true);
 382    if (ret < 0) {
 383        goto exit;
 384    }
 385    s->curr_header = hdr_idx;
 386
 387exit:
 388    return ret;
 389}
 390
 391/*
 392 * The VHDX spec calls for header updates to be performed twice, so that both
 393 * the current and non-current header have valid info
 394 */
 395int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s,
 396                        bool generate_data_write_guid, MSGUID *log_guid)
 397{
 398    int ret;
 399
 400    ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
 401    if (ret < 0) {
 402        return ret;
 403    }
 404    ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
 405    return ret;
 406}
 407
 408/* opens the specified header block from the VHDX file header section */
 409static void vhdx_parse_header(BlockDriverState *bs, BDRVVHDXState *s,
 410                              Error **errp)
 411{
 412    int ret;
 413    VHDXHeader *header1;
 414    VHDXHeader *header2;
 415    bool h1_valid = false;
 416    bool h2_valid = false;
 417    uint64_t h1_seq = 0;
 418    uint64_t h2_seq = 0;
 419    uint8_t *buffer;
 420
 421    /* header1 & header2 are freed in vhdx_close() */
 422    header1 = qemu_blockalign(bs, sizeof(VHDXHeader));
 423    header2 = qemu_blockalign(bs, sizeof(VHDXHeader));
 424
 425    buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE);
 426
 427    s->headers[0] = header1;
 428    s->headers[1] = header2;
 429
 430    /* We have to read the whole VHDX_HEADER_SIZE instead of
 431     * sizeof(VHDXHeader), because the checksum is over the whole
 432     * region */
 433    ret = bdrv_pread(bs->file->bs, VHDX_HEADER1_OFFSET, buffer,
 434                     VHDX_HEADER_SIZE);
 435    if (ret < 0) {
 436        goto fail;
 437    }
 438    /* copy over just the relevant portion that we need */
 439    memcpy(header1, buffer, sizeof(VHDXHeader));
 440
 441    if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4)) {
 442        vhdx_header_le_import(header1);
 443        if (header1->signature == VHDX_HEADER_SIGNATURE &&
 444            header1->version == 1) {
 445            h1_seq = header1->sequence_number;
 446            h1_valid = true;
 447        }
 448    }
 449
 450    ret = bdrv_pread(bs->file->bs, VHDX_HEADER2_OFFSET, buffer,
 451                     VHDX_HEADER_SIZE);
 452    if (ret < 0) {
 453        goto fail;
 454    }
 455    /* copy over just the relevant portion that we need */
 456    memcpy(header2, buffer, sizeof(VHDXHeader));
 457
 458    if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4)) {
 459        vhdx_header_le_import(header2);
 460        if (header2->signature == VHDX_HEADER_SIGNATURE &&
 461            header2->version == 1) {
 462            h2_seq = header2->sequence_number;
 463            h2_valid = true;
 464        }
 465    }
 466
 467    /* If there is only 1 valid header (or no valid headers), we
 468     * don't care what the sequence numbers are */
 469    if (h1_valid && !h2_valid) {
 470        s->curr_header = 0;
 471    } else if (!h1_valid && h2_valid) {
 472        s->curr_header = 1;
 473    } else if (!h1_valid && !h2_valid) {
 474        goto fail;
 475    } else {
 476        /* If both headers are valid, then we choose the active one by the
 477         * highest sequence number.  If the sequence numbers are equal, that is
 478         * invalid */
 479        if (h1_seq > h2_seq) {
 480            s->curr_header = 0;
 481        } else if (h2_seq > h1_seq) {
 482            s->curr_header = 1;
 483        } else {
 484            /* The Microsoft Disk2VHD tool will create 2 identical
 485             * headers, with identical sequence numbers.  If the headers are
 486             * identical, don't consider the file corrupt */
 487            if (!memcmp(header1, header2, sizeof(VHDXHeader))) {
 488                s->curr_header = 0;
 489            } else {
 490                goto fail;
 491            }
 492        }
 493    }
 494
 495    vhdx_region_register(s, s->headers[s->curr_header]->log_offset,
 496                            s->headers[s->curr_header]->log_length);
 497    goto exit;
 498
 499fail:
 500    error_setg_errno(errp, -ret, "No valid VHDX header found");
 501    qemu_vfree(header1);
 502    qemu_vfree(header2);
 503    s->headers[0] = NULL;
 504    s->headers[1] = NULL;
 505exit:
 506    qemu_vfree(buffer);
 507}
 508
 509
 510static int vhdx_open_region_tables(BlockDriverState *bs, BDRVVHDXState *s)
 511{
 512    int ret = 0;
 513    uint8_t *buffer;
 514    int offset = 0;
 515    VHDXRegionTableEntry rt_entry;
 516    uint32_t i;
 517    bool bat_rt_found = false;
 518    bool metadata_rt_found = false;
 519
 520    /* We have to read the whole 64KB block, because the crc32 is over the
 521     * whole block */
 522    buffer = qemu_blockalign(bs, VHDX_HEADER_BLOCK_SIZE);
 523
 524    ret = bdrv_pread(bs->file->bs, VHDX_REGION_TABLE_OFFSET, buffer,
 525                     VHDX_HEADER_BLOCK_SIZE);
 526    if (ret < 0) {
 527        goto fail;
 528    }
 529    memcpy(&s->rt, buffer, sizeof(s->rt));
 530    offset += sizeof(s->rt);
 531
 532    if (!vhdx_checksum_is_valid(buffer, VHDX_HEADER_BLOCK_SIZE, 4)) {
 533        ret = -EINVAL;
 534        goto fail;
 535    }
 536
 537    vhdx_region_header_le_import(&s->rt);
 538
 539    if (s->rt.signature != VHDX_REGION_SIGNATURE) {
 540        ret = -EINVAL;
 541        goto fail;
 542    }
 543
 544
 545    /* Per spec, maximum region table entry count is 2047 */
 546    if (s->rt.entry_count > 2047) {
 547        ret = -EINVAL;
 548        goto fail;
 549    }
 550
 551    for (i = 0; i < s->rt.entry_count; i++) {
 552        memcpy(&rt_entry, buffer + offset, sizeof(rt_entry));
 553        offset += sizeof(rt_entry);
 554
 555        vhdx_region_entry_le_import(&rt_entry);
 556
 557        /* check for region overlap between these entries, and any
 558         * other memory regions in the file */
 559        ret = vhdx_region_check(s, rt_entry.file_offset, rt_entry.length);
 560        if (ret < 0) {
 561            goto fail;
 562        }
 563
 564        vhdx_region_register(s, rt_entry.file_offset, rt_entry.length);
 565
 566        /* see if we recognize the entry */
 567        if (guid_eq(rt_entry.guid, bat_guid)) {
 568            /* must be unique; if we have already found it this is invalid */
 569            if (bat_rt_found) {
 570                ret = -EINVAL;
 571                goto fail;
 572            }
 573            bat_rt_found = true;
 574            s->bat_rt = rt_entry;
 575            continue;
 576        }
 577
 578        if (guid_eq(rt_entry.guid, metadata_guid)) {
 579            /* must be unique; if we have already found it this is invalid */
 580            if (metadata_rt_found) {
 581                ret = -EINVAL;
 582                goto fail;
 583            }
 584            metadata_rt_found = true;
 585            s->metadata_rt = rt_entry;
 586            continue;
 587        }
 588
 589        if (rt_entry.data_bits & VHDX_REGION_ENTRY_REQUIRED) {
 590            /* cannot read vhdx file - required region table entry that
 591             * we do not understand.  per spec, we must fail to open */
 592            ret = -ENOTSUP;
 593            goto fail;
 594        }
 595    }
 596
 597    if (!bat_rt_found || !metadata_rt_found) {
 598        ret = -EINVAL;
 599        goto fail;
 600    }
 601
 602    ret = 0;
 603
 604fail:
 605    qemu_vfree(buffer);
 606    return ret;
 607}
 608
 609
 610
 611/* Metadata initial parser
 612 *
 613 * This loads all the metadata entry fields.  This may cause additional
 614 * fields to be processed (e.g. parent locator, etc..).
 615 *
 616 * There are 5 Metadata items that are always required:
 617 *      - File Parameters (block size, has a parent)
 618 *      - Virtual Disk Size (size, in bytes, of the virtual drive)
 619 *      - Page 83 Data (scsi page 83 guid)
 620 *      - Logical Sector Size (logical sector size in bytes, either 512 or
 621 *                             4096.  We only support 512 currently)
 622 *      - Physical Sector Size (512 or 4096)
 623 *
 624 * Also, if the File Parameters indicate this is a differencing file,
 625 * we must also look for the Parent Locator metadata item.
 626 */
 627static int vhdx_parse_metadata(BlockDriverState *bs, BDRVVHDXState *s)
 628{
 629    int ret = 0;
 630    uint8_t *buffer;
 631    int offset = 0;
 632    uint32_t i = 0;
 633    VHDXMetadataTableEntry md_entry;
 634
 635    buffer = qemu_blockalign(bs, VHDX_METADATA_TABLE_MAX_SIZE);
 636
 637    ret = bdrv_pread(bs->file->bs, s->metadata_rt.file_offset, buffer,
 638                     VHDX_METADATA_TABLE_MAX_SIZE);
 639    if (ret < 0) {
 640        goto exit;
 641    }
 642    memcpy(&s->metadata_hdr, buffer, sizeof(s->metadata_hdr));
 643    offset += sizeof(s->metadata_hdr);
 644
 645    vhdx_metadata_header_le_import(&s->metadata_hdr);
 646
 647    if (s->metadata_hdr.signature != VHDX_METADATA_SIGNATURE) {
 648        ret = -EINVAL;
 649        goto exit;
 650    }
 651
 652    s->metadata_entries.present = 0;
 653
 654    if ((s->metadata_hdr.entry_count * sizeof(md_entry)) >
 655        (VHDX_METADATA_TABLE_MAX_SIZE - offset)) {
 656        ret = -EINVAL;
 657        goto exit;
 658    }
 659
 660    for (i = 0; i < s->metadata_hdr.entry_count; i++) {
 661        memcpy(&md_entry, buffer + offset, sizeof(md_entry));
 662        offset += sizeof(md_entry);
 663
 664        vhdx_metadata_entry_le_import(&md_entry);
 665
 666        if (guid_eq(md_entry.item_id, file_param_guid)) {
 667            if (s->metadata_entries.present & META_FILE_PARAMETER_PRESENT) {
 668                ret = -EINVAL;
 669                goto exit;
 670            }
 671            s->metadata_entries.file_parameters_entry = md_entry;
 672            s->metadata_entries.present |= META_FILE_PARAMETER_PRESENT;
 673            continue;
 674        }
 675
 676        if (guid_eq(md_entry.item_id, virtual_size_guid)) {
 677            if (s->metadata_entries.present & META_VIRTUAL_DISK_SIZE_PRESENT) {
 678                ret = -EINVAL;
 679                goto exit;
 680            }
 681            s->metadata_entries.virtual_disk_size_entry = md_entry;
 682            s->metadata_entries.present |= META_VIRTUAL_DISK_SIZE_PRESENT;
 683            continue;
 684        }
 685
 686        if (guid_eq(md_entry.item_id, page83_guid)) {
 687            if (s->metadata_entries.present & META_PAGE_83_PRESENT) {
 688                ret = -EINVAL;
 689                goto exit;
 690            }
 691            s->metadata_entries.page83_data_entry = md_entry;
 692            s->metadata_entries.present |= META_PAGE_83_PRESENT;
 693            continue;
 694        }
 695
 696        if (guid_eq(md_entry.item_id, logical_sector_guid)) {
 697            if (s->metadata_entries.present &
 698                META_LOGICAL_SECTOR_SIZE_PRESENT) {
 699                ret = -EINVAL;
 700                goto exit;
 701            }
 702            s->metadata_entries.logical_sector_size_entry = md_entry;
 703            s->metadata_entries.present |= META_LOGICAL_SECTOR_SIZE_PRESENT;
 704            continue;
 705        }
 706
 707        if (guid_eq(md_entry.item_id, phys_sector_guid)) {
 708            if (s->metadata_entries.present & META_PHYS_SECTOR_SIZE_PRESENT) {
 709                ret = -EINVAL;
 710                goto exit;
 711            }
 712            s->metadata_entries.phys_sector_size_entry = md_entry;
 713            s->metadata_entries.present |= META_PHYS_SECTOR_SIZE_PRESENT;
 714            continue;
 715        }
 716
 717        if (guid_eq(md_entry.item_id, parent_locator_guid)) {
 718            if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
 719                ret = -EINVAL;
 720                goto exit;
 721            }
 722            s->metadata_entries.parent_locator_entry = md_entry;
 723            s->metadata_entries.present |= META_PARENT_LOCATOR_PRESENT;
 724            continue;
 725        }
 726
 727        if (md_entry.data_bits & VHDX_META_FLAGS_IS_REQUIRED) {
 728            /* cannot read vhdx file - required region table entry that
 729             * we do not understand.  per spec, we must fail to open */
 730            ret = -ENOTSUP;
 731            goto exit;
 732        }
 733    }
 734
 735    if (s->metadata_entries.present != META_ALL_PRESENT) {
 736        ret = -ENOTSUP;
 737        goto exit;
 738    }
 739
 740    ret = bdrv_pread(bs->file->bs,
 741                     s->metadata_entries.file_parameters_entry.offset
 742                                         + s->metadata_rt.file_offset,
 743                     &s->params,
 744                     sizeof(s->params));
 745
 746    if (ret < 0) {
 747        goto exit;
 748    }
 749
 750    le32_to_cpus(&s->params.block_size);
 751    le32_to_cpus(&s->params.data_bits);
 752
 753
 754    /* We now have the file parameters, so we can tell if this is a
 755     * differencing file (i.e.. has_parent), is dynamic or fixed
 756     * sized (leave_blocks_allocated), and the block size */
 757
 758    /* The parent locator required iff the file parameters has_parent set */
 759    if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
 760        if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
 761            /* TODO: parse  parent locator fields */
 762            ret = -ENOTSUP; /* temp, until differencing files are supported */
 763            goto exit;
 764        } else {
 765            /* if has_parent is set, but there is not parent locator present,
 766             * then that is an invalid combination */
 767            ret = -EINVAL;
 768            goto exit;
 769        }
 770    }
 771
 772    /* determine virtual disk size, logical sector size,
 773     * and phys sector size */
 774
 775    ret = bdrv_pread(bs->file->bs,
 776                     s->metadata_entries.virtual_disk_size_entry.offset
 777                                           + s->metadata_rt.file_offset,
 778                     &s->virtual_disk_size,
 779                     sizeof(uint64_t));
 780    if (ret < 0) {
 781        goto exit;
 782    }
 783    ret = bdrv_pread(bs->file->bs,
 784                     s->metadata_entries.logical_sector_size_entry.offset
 785                                             + s->metadata_rt.file_offset,
 786                     &s->logical_sector_size,
 787                     sizeof(uint32_t));
 788    if (ret < 0) {
 789        goto exit;
 790    }
 791    ret = bdrv_pread(bs->file->bs,
 792                     s->metadata_entries.phys_sector_size_entry.offset
 793                                          + s->metadata_rt.file_offset,
 794                     &s->physical_sector_size,
 795                     sizeof(uint32_t));
 796    if (ret < 0) {
 797        goto exit;
 798    }
 799
 800    le64_to_cpus(&s->virtual_disk_size);
 801    le32_to_cpus(&s->logical_sector_size);
 802    le32_to_cpus(&s->physical_sector_size);
 803
 804    if (s->params.block_size < VHDX_BLOCK_SIZE_MIN ||
 805        s->params.block_size > VHDX_BLOCK_SIZE_MAX) {
 806        ret = -EINVAL;
 807        goto exit;
 808    }
 809
 810    /* only 2 supported sector sizes */
 811    if (s->logical_sector_size != 512 && s->logical_sector_size != 4096) {
 812        ret = -EINVAL;
 813        goto exit;
 814    }
 815
 816    /* Both block_size and sector_size are guaranteed powers of 2, below.
 817       Due to range checks above, s->sectors_per_block can never be < 256 */
 818    s->sectors_per_block = s->params.block_size / s->logical_sector_size;
 819    s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
 820                     (uint64_t)s->logical_sector_size /
 821                     (uint64_t)s->params.block_size;
 822
 823    /* These values are ones we will want to use for division / multiplication
 824     * later on, and they are all guaranteed (per the spec) to be powers of 2,
 825     * so we can take advantage of that for shift operations during
 826     * reads/writes */
 827    if (s->logical_sector_size & (s->logical_sector_size - 1)) {
 828        ret = -EINVAL;
 829        goto exit;
 830    }
 831    if (s->sectors_per_block & (s->sectors_per_block - 1)) {
 832        ret = -EINVAL;
 833        goto exit;
 834    }
 835    if (s->chunk_ratio & (s->chunk_ratio - 1)) {
 836        ret = -EINVAL;
 837        goto exit;
 838    }
 839    s->block_size = s->params.block_size;
 840    if (s->block_size & (s->block_size - 1)) {
 841        ret = -EINVAL;
 842        goto exit;
 843    }
 844
 845    vhdx_set_shift_bits(s);
 846
 847    ret = 0;
 848
 849exit:
 850    qemu_vfree(buffer);
 851    return ret;
 852}
 853
 854/*
 855 * Calculate the number of BAT entries, including sector
 856 * bitmap entries.
 857 */
 858static void vhdx_calc_bat_entries(BDRVVHDXState *s)
 859{
 860    uint32_t data_blocks_cnt, bitmap_blocks_cnt;
 861
 862    data_blocks_cnt = DIV_ROUND_UP(s->virtual_disk_size, s->block_size);
 863    bitmap_blocks_cnt = DIV_ROUND_UP(data_blocks_cnt, s->chunk_ratio);
 864
 865    if (s->parent_entries) {
 866        s->bat_entries = bitmap_blocks_cnt * (s->chunk_ratio + 1);
 867    } else {
 868        s->bat_entries = data_blocks_cnt +
 869                         ((data_blocks_cnt - 1) >> s->chunk_ratio_bits);
 870    }
 871
 872}
 873
 874static void vhdx_close(BlockDriverState *bs)
 875{
 876    BDRVVHDXState *s = bs->opaque;
 877    qemu_vfree(s->headers[0]);
 878    s->headers[0] = NULL;
 879    qemu_vfree(s->headers[1]);
 880    s->headers[1] = NULL;
 881    qemu_vfree(s->bat);
 882    s->bat = NULL;
 883    qemu_vfree(s->parent_entries);
 884    s->parent_entries = NULL;
 885    migrate_del_blocker(s->migration_blocker);
 886    error_free(s->migration_blocker);
 887    qemu_vfree(s->log.hdr);
 888    s->log.hdr = NULL;
 889    vhdx_region_unregister_all(s);
 890}
 891
 892static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
 893                     Error **errp)
 894{
 895    BDRVVHDXState *s = bs->opaque;
 896    int ret = 0;
 897    uint32_t i;
 898    uint64_t signature;
 899    Error *local_err = NULL;
 900
 901    s->bat = NULL;
 902    s->first_visible_write = true;
 903
 904    qemu_co_mutex_init(&s->lock);
 905    QLIST_INIT(&s->regions);
 906
 907    /* validate the file signature */
 908    ret = bdrv_pread(bs->file->bs, 0, &signature, sizeof(uint64_t));
 909    if (ret < 0) {
 910        goto fail;
 911    }
 912    if (memcmp(&signature, "vhdxfile", 8)) {
 913        ret = -EINVAL;
 914        goto fail;
 915    }
 916
 917    /* This is used for any header updates, for the file_write_guid.
 918     * The spec dictates that a new value should be used for the first
 919     * header update */
 920    vhdx_guid_generate(&s->session_guid);
 921
 922    vhdx_parse_header(bs, s, &local_err);
 923    if (local_err != NULL) {
 924        error_propagate(errp, local_err);
 925        ret = -EINVAL;
 926        goto fail;
 927    }
 928
 929    ret = vhdx_parse_log(bs, s, &s->log_replayed_on_open, errp);
 930    if (ret < 0) {
 931        goto fail;
 932    }
 933
 934    ret = vhdx_open_region_tables(bs, s);
 935    if (ret < 0) {
 936        goto fail;
 937    }
 938
 939    ret = vhdx_parse_metadata(bs, s);
 940    if (ret < 0) {
 941        goto fail;
 942    }
 943
 944    s->block_size = s->params.block_size;
 945
 946    /* the VHDX spec dictates that virtual_disk_size is always a multiple of
 947     * logical_sector_size */
 948    bs->total_sectors = s->virtual_disk_size >> s->logical_sector_size_bits;
 949
 950    vhdx_calc_bat_entries(s);
 951
 952    s->bat_offset = s->bat_rt.file_offset;
 953
 954    if (s->bat_entries > s->bat_rt.length / sizeof(VHDXBatEntry)) {
 955        /* BAT allocation is not large enough for all entries */
 956        ret = -EINVAL;
 957        goto fail;
 958    }
 959
 960    /* s->bat is freed in vhdx_close() */
 961    s->bat = qemu_try_blockalign(bs->file->bs, s->bat_rt.length);
 962    if (s->bat == NULL) {
 963        ret = -ENOMEM;
 964        goto fail;
 965    }
 966
 967    ret = bdrv_pread(bs->file->bs, s->bat_offset, s->bat, s->bat_rt.length);
 968    if (ret < 0) {
 969        goto fail;
 970    }
 971
 972    uint64_t payblocks = s->chunk_ratio;
 973    /* endian convert, and verify populated BAT field file offsets against
 974     * region table and log entries */
 975    for (i = 0; i < s->bat_entries; i++) {
 976        le64_to_cpus(&s->bat[i]);
 977        if (payblocks--) {
 978            /* payload bat entries */
 979            if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) ==
 980                    PAYLOAD_BLOCK_FULLY_PRESENT) {
 981                ret = vhdx_region_check(s, s->bat[i] & VHDX_BAT_FILE_OFF_MASK,
 982                                        s->block_size);
 983                if (ret < 0) {
 984                    goto fail;
 985                }
 986            }
 987        } else {
 988            payblocks = s->chunk_ratio;
 989            /* Once differencing files are supported, verify sector bitmap
 990             * blocks here */
 991        }
 992    }
 993
 994    if (flags & BDRV_O_RDWR) {
 995        ret = vhdx_update_headers(bs, s, false, NULL);
 996        if (ret < 0) {
 997            goto fail;
 998        }
 999    }
1000
1001    /* TODO: differencing files */
1002
1003    /* Disable migration when VHDX images are used */
1004    error_setg(&s->migration_blocker, "The vhdx format used by node '%s' "
1005               "does not support live migration",
1006               bdrv_get_device_or_node_name(bs));
1007    migrate_add_blocker(s->migration_blocker);
1008
1009    return 0;
1010fail:
1011    vhdx_close(bs);
1012    return ret;
1013}
1014
1015static int vhdx_reopen_prepare(BDRVReopenState *state,
1016                               BlockReopenQueue *queue, Error **errp)
1017{
1018    return 0;
1019}
1020
1021
1022/*
1023 * Perform sector to block offset translations, to get various
1024 * sector and file offsets into the image.  See VHDXSectorInfo
1025 */
1026static void vhdx_block_translate(BDRVVHDXState *s, int64_t sector_num,
1027                                 int nb_sectors, VHDXSectorInfo *sinfo)
1028{
1029    uint32_t block_offset;
1030
1031    sinfo->bat_idx = sector_num >> s->sectors_per_block_bits;
1032    /* effectively a modulo - this gives us the offset into the block
1033     * (in sector sizes) for our sector number */
1034    block_offset = sector_num - (sinfo->bat_idx << s->sectors_per_block_bits);
1035    /* the chunk ratio gives us the interleaving of the sector
1036     * bitmaps, so we need to advance our page block index by the
1037     * sector bitmaps entry number */
1038    sinfo->bat_idx += sinfo->bat_idx >> s->chunk_ratio_bits;
1039
1040    /* the number of sectors we can read/write in this cycle */
1041    sinfo->sectors_avail = s->sectors_per_block - block_offset;
1042
1043    sinfo->bytes_left = sinfo->sectors_avail << s->logical_sector_size_bits;
1044
1045    if (sinfo->sectors_avail > nb_sectors) {
1046        sinfo->sectors_avail = nb_sectors;
1047    }
1048
1049    sinfo->bytes_avail = sinfo->sectors_avail << s->logical_sector_size_bits;
1050
1051    sinfo->file_offset = s->bat[sinfo->bat_idx] & VHDX_BAT_FILE_OFF_MASK;
1052
1053    sinfo->block_offset = block_offset << s->logical_sector_size_bits;
1054
1055    /* The file offset must be past the header section, so must be > 0 */
1056    if (sinfo->file_offset == 0) {
1057        return;
1058    }
1059
1060    /* block offset is the offset in vhdx logical sectors, in
1061     * the payload data block. Convert that to a byte offset
1062     * in the block, and add in the payload data block offset
1063     * in the file, in bytes, to get the final read address */
1064
1065    sinfo->file_offset += sinfo->block_offset;
1066}
1067
1068
1069static int vhdx_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1070{
1071    BDRVVHDXState *s = bs->opaque;
1072
1073    bdi->cluster_size = s->block_size;
1074
1075    bdi->unallocated_blocks_are_zero =
1076        (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) == 0;
1077
1078    return 0;
1079}
1080
1081
1082static coroutine_fn int vhdx_co_readv(BlockDriverState *bs, int64_t sector_num,
1083                                      int nb_sectors, QEMUIOVector *qiov)
1084{
1085    BDRVVHDXState *s = bs->opaque;
1086    int ret = 0;
1087    VHDXSectorInfo sinfo;
1088    uint64_t bytes_done = 0;
1089    QEMUIOVector hd_qiov;
1090
1091    qemu_iovec_init(&hd_qiov, qiov->niov);
1092
1093    qemu_co_mutex_lock(&s->lock);
1094
1095    while (nb_sectors > 0) {
1096        /* We are a differencing file, so we need to inspect the sector bitmap
1097         * to see if we have the data or not */
1098        if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1099            /* not supported yet */
1100            ret = -ENOTSUP;
1101            goto exit;
1102        } else {
1103            vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1104
1105            qemu_iovec_reset(&hd_qiov);
1106            qemu_iovec_concat(&hd_qiov, qiov,  bytes_done, sinfo.bytes_avail);
1107
1108            /* check the payload block state */
1109            switch (s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK) {
1110            case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1111            case PAYLOAD_BLOCK_UNDEFINED:
1112            case PAYLOAD_BLOCK_UNMAPPED:
1113            case PAYLOAD_BLOCK_UNMAPPED_v095:
1114            case PAYLOAD_BLOCK_ZERO:
1115                /* return zero */
1116                qemu_iovec_memset(&hd_qiov, 0, 0, sinfo.bytes_avail);
1117                break;
1118            case PAYLOAD_BLOCK_FULLY_PRESENT:
1119                qemu_co_mutex_unlock(&s->lock);
1120                ret = bdrv_co_readv(bs->file->bs,
1121                                    sinfo.file_offset >> BDRV_SECTOR_BITS,
1122                                    sinfo.sectors_avail, &hd_qiov);
1123                qemu_co_mutex_lock(&s->lock);
1124                if (ret < 0) {
1125                    goto exit;
1126                }
1127                break;
1128            case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1129                /* we don't yet support difference files, fall through
1130                 * to error */
1131            default:
1132                ret = -EIO;
1133                goto exit;
1134                break;
1135            }
1136            nb_sectors -= sinfo.sectors_avail;
1137            sector_num += sinfo.sectors_avail;
1138            bytes_done += sinfo.bytes_avail;
1139        }
1140    }
1141    ret = 0;
1142exit:
1143    qemu_co_mutex_unlock(&s->lock);
1144    qemu_iovec_destroy(&hd_qiov);
1145    return ret;
1146}
1147
1148/*
1149 * Allocate a new payload block at the end of the file.
1150 *
1151 * Allocation will happen at 1MB alignment inside the file
1152 *
1153 * Returns the file offset start of the new payload block
1154 */
1155static int vhdx_allocate_block(BlockDriverState *bs, BDRVVHDXState *s,
1156                                    uint64_t *new_offset)
1157{
1158    *new_offset = bdrv_getlength(bs->file->bs);
1159
1160    /* per the spec, the address for a block is in units of 1MB */
1161    *new_offset = ROUND_UP(*new_offset, 1024 * 1024);
1162
1163    return bdrv_truncate(bs->file->bs, *new_offset + s->block_size);
1164}
1165
1166/*
1167 * Update the BAT table entry with the new file offset, and the new entry
1168 * state */
1169static void vhdx_update_bat_table_entry(BlockDriverState *bs, BDRVVHDXState *s,
1170                                       VHDXSectorInfo *sinfo,
1171                                       uint64_t *bat_entry_le,
1172                                       uint64_t *bat_offset, int state)
1173{
1174    /* The BAT entry is a uint64, with 44 bits for the file offset in units of
1175     * 1MB, and 3 bits for the block state. */
1176    if ((state == PAYLOAD_BLOCK_ZERO)        ||
1177        (state == PAYLOAD_BLOCK_UNDEFINED)   ||
1178        (state == PAYLOAD_BLOCK_NOT_PRESENT) ||
1179        (state == PAYLOAD_BLOCK_UNMAPPED)) {
1180        s->bat[sinfo->bat_idx]  = 0;  /* For PAYLOAD_BLOCK_ZERO, the
1181                                         FileOffsetMB field is denoted as
1182                                         'reserved' in the v1.0 spec.  If it is
1183                                         non-zero, MS Hyper-V will fail to read
1184                                         the disk image */
1185    } else {
1186        s->bat[sinfo->bat_idx]  = sinfo->file_offset;
1187    }
1188
1189    s->bat[sinfo->bat_idx] |= state & VHDX_BAT_STATE_BIT_MASK;
1190
1191    *bat_entry_le = cpu_to_le64(s->bat[sinfo->bat_idx]);
1192    *bat_offset = s->bat_offset + sinfo->bat_idx * sizeof(VHDXBatEntry);
1193
1194}
1195
1196/* Per the spec, on the first write of guest-visible data to the file the
1197 * data write guid must be updated in the header */
1198int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s)
1199{
1200    int ret = 0;
1201    if (s->first_visible_write) {
1202        s->first_visible_write = false;
1203        ret = vhdx_update_headers(bs, s, true, NULL);
1204    }
1205    return ret;
1206}
1207
1208static coroutine_fn int vhdx_co_writev(BlockDriverState *bs, int64_t sector_num,
1209                                      int nb_sectors, QEMUIOVector *qiov)
1210{
1211    int ret = -ENOTSUP;
1212    BDRVVHDXState *s = bs->opaque;
1213    VHDXSectorInfo sinfo;
1214    uint64_t bytes_done = 0;
1215    uint64_t bat_entry = 0;
1216    uint64_t bat_entry_offset = 0;
1217    QEMUIOVector hd_qiov;
1218    struct iovec iov1 = { 0 };
1219    struct iovec iov2 = { 0 };
1220    int sectors_to_write;
1221    int bat_state;
1222    uint64_t bat_prior_offset = 0;
1223    bool bat_update = false;
1224
1225    qemu_iovec_init(&hd_qiov, qiov->niov);
1226
1227    qemu_co_mutex_lock(&s->lock);
1228
1229    ret = vhdx_user_visible_write(bs, s);
1230    if (ret < 0) {
1231        goto exit;
1232    }
1233
1234    while (nb_sectors > 0) {
1235        bool use_zero_buffers = false;
1236        bat_update = false;
1237        if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1238            /* not supported yet */
1239            ret = -ENOTSUP;
1240            goto exit;
1241        } else {
1242            vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1243            sectors_to_write = sinfo.sectors_avail;
1244
1245            qemu_iovec_reset(&hd_qiov);
1246            /* check the payload block state */
1247            bat_state = s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK;
1248            switch (bat_state) {
1249            case PAYLOAD_BLOCK_ZERO:
1250                /* in this case, we need to preserve zero writes for
1251                 * data that is not part of this write, so we must pad
1252                 * the rest of the buffer to zeroes */
1253
1254                /* if we are on a posix system with ftruncate() that extends
1255                 * a file, then it is zero-filled for us.  On Win32, the raw
1256                 * layer uses SetFilePointer and SetFileEnd, which does not
1257                 * zero fill AFAIK */
1258
1259                /* Queue another write of zero buffers if the underlying file
1260                 * does not zero-fill on file extension */
1261
1262                if (bdrv_has_zero_init(bs->file->bs) == 0) {
1263                    use_zero_buffers = true;
1264
1265                    /* zero fill the front, if any */
1266                    if (sinfo.block_offset) {
1267                        iov1.iov_len = sinfo.block_offset;
1268                        iov1.iov_base = qemu_blockalign(bs, iov1.iov_len);
1269                        memset(iov1.iov_base, 0, iov1.iov_len);
1270                        qemu_iovec_concat_iov(&hd_qiov, &iov1, 1, 0,
1271                                              iov1.iov_len);
1272                        sectors_to_write += iov1.iov_len >> BDRV_SECTOR_BITS;
1273                    }
1274
1275                    /* our actual data */
1276                    qemu_iovec_concat(&hd_qiov, qiov,  bytes_done,
1277                                      sinfo.bytes_avail);
1278
1279                    /* zero fill the back, if any */
1280                    if ((sinfo.bytes_avail - sinfo.block_offset) <
1281                         s->block_size) {
1282                        iov2.iov_len = s->block_size -
1283                                      (sinfo.bytes_avail + sinfo.block_offset);
1284                        iov2.iov_base = qemu_blockalign(bs, iov2.iov_len);
1285                        memset(iov2.iov_base, 0, iov2.iov_len);
1286                        qemu_iovec_concat_iov(&hd_qiov, &iov2, 1, 0,
1287                                              iov2.iov_len);
1288                        sectors_to_write += iov2.iov_len >> BDRV_SECTOR_BITS;
1289                    }
1290                }
1291                /* fall through */
1292            case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1293            case PAYLOAD_BLOCK_UNMAPPED:
1294            case PAYLOAD_BLOCK_UNMAPPED_v095:
1295            case PAYLOAD_BLOCK_UNDEFINED:
1296                bat_prior_offset = sinfo.file_offset;
1297                ret = vhdx_allocate_block(bs, s, &sinfo.file_offset);
1298                if (ret < 0) {
1299                    goto exit;
1300                }
1301                /* once we support differencing files, this may also be
1302                 * partially present */
1303                /* update block state to the newly specified state */
1304                vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1305                                            &bat_entry_offset,
1306                                            PAYLOAD_BLOCK_FULLY_PRESENT);
1307                bat_update = true;
1308                /* since we just allocated a block, file_offset is the
1309                 * beginning of the payload block. It needs to be the
1310                 * write address, which includes the offset into the block */
1311                if (!use_zero_buffers) {
1312                    sinfo.file_offset += sinfo.block_offset;
1313                }
1314                /* fall through */
1315            case PAYLOAD_BLOCK_FULLY_PRESENT:
1316                /* if the file offset address is in the header zone,
1317                 * there is a problem */
1318                if (sinfo.file_offset < (1024 * 1024)) {
1319                    ret = -EFAULT;
1320                    goto error_bat_restore;
1321                }
1322
1323                if (!use_zero_buffers) {
1324                    qemu_iovec_concat(&hd_qiov, qiov,  bytes_done,
1325                                      sinfo.bytes_avail);
1326                }
1327                /* block exists, so we can just overwrite it */
1328                qemu_co_mutex_unlock(&s->lock);
1329                ret = bdrv_co_writev(bs->file->bs,
1330                                    sinfo.file_offset >> BDRV_SECTOR_BITS,
1331                                    sectors_to_write, &hd_qiov);
1332                qemu_co_mutex_lock(&s->lock);
1333                if (ret < 0) {
1334                    goto error_bat_restore;
1335                }
1336                break;
1337            case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1338                /* we don't yet support difference files, fall through
1339                 * to error */
1340            default:
1341                ret = -EIO;
1342                goto exit;
1343                break;
1344            }
1345
1346            if (bat_update) {
1347                /* this will update the BAT entry into the log journal, and
1348                 * then flush the log journal out to disk */
1349                ret =  vhdx_log_write_and_flush(bs, s, &bat_entry,
1350                                                sizeof(VHDXBatEntry),
1351                                                bat_entry_offset);
1352                if (ret < 0) {
1353                    goto exit;
1354                }
1355            }
1356
1357            nb_sectors -= sinfo.sectors_avail;
1358            sector_num += sinfo.sectors_avail;
1359            bytes_done += sinfo.bytes_avail;
1360
1361        }
1362    }
1363
1364    goto exit;
1365
1366error_bat_restore:
1367    if (bat_update) {
1368        /* keep metadata in sync, and restore the bat entry state
1369         * if error. */
1370        sinfo.file_offset = bat_prior_offset;
1371        vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1372                                    &bat_entry_offset, bat_state);
1373    }
1374exit:
1375    qemu_vfree(iov1.iov_base);
1376    qemu_vfree(iov2.iov_base);
1377    qemu_co_mutex_unlock(&s->lock);
1378    qemu_iovec_destroy(&hd_qiov);
1379    return ret;
1380}
1381
1382
1383
1384/*
1385 * Create VHDX Headers
1386 *
1387 * There are 2 headers, and the highest sequence number will represent
1388 * the active header
1389 */
1390static int vhdx_create_new_headers(BlockDriverState *bs, uint64_t image_size,
1391                                   uint32_t log_size)
1392{
1393    int ret = 0;
1394    VHDXHeader *hdr = NULL;
1395
1396    hdr = g_new0(VHDXHeader, 1);
1397
1398    hdr->signature       = VHDX_HEADER_SIGNATURE;
1399    hdr->sequence_number = g_random_int();
1400    hdr->log_version     = 0;
1401    hdr->version         = 1;
1402    hdr->log_length      = log_size;
1403    hdr->log_offset      = VHDX_HEADER_SECTION_END;
1404    vhdx_guid_generate(&hdr->file_write_guid);
1405    vhdx_guid_generate(&hdr->data_write_guid);
1406
1407    ret = vhdx_write_header(bs, hdr, VHDX_HEADER1_OFFSET, false);
1408    if (ret < 0) {
1409        goto exit;
1410    }
1411    hdr->sequence_number++;
1412    ret = vhdx_write_header(bs, hdr, VHDX_HEADER2_OFFSET, false);
1413    if (ret < 0) {
1414        goto exit;
1415    }
1416
1417exit:
1418    g_free(hdr);
1419    return ret;
1420}
1421
1422#define VHDX_METADATA_ENTRY_BUFFER_SIZE \
1423                                    (sizeof(VHDXFileParameters)               +\
1424                                     sizeof(VHDXVirtualDiskSize)              +\
1425                                     sizeof(VHDXPage83Data)                   +\
1426                                     sizeof(VHDXVirtualDiskLogicalSectorSize) +\
1427                                     sizeof(VHDXVirtualDiskPhysicalSectorSize))
1428
1429/*
1430 * Create the Metadata entries.
1431 *
1432 * For more details on the entries, see section 3.5 (pg 29) in the
1433 * VHDX 1.00 specification.
1434 *
1435 * We support 5 metadata entries (all required by spec):
1436 *          File Parameters,
1437 *          Virtual Disk Size,
1438 *          Page 83 Data,
1439 *          Logical Sector Size,
1440 *          Physical Sector Size
1441 *
1442 * The first 64KB of the Metadata section is reserved for the metadata
1443 * header and entries; beyond that, the metadata items themselves reside.
1444 */
1445static int vhdx_create_new_metadata(BlockDriverState *bs,
1446                                    uint64_t image_size,
1447                                    uint32_t block_size,
1448                                    uint32_t sector_size,
1449                                    uint64_t metadata_offset,
1450                                    VHDXImageType type)
1451{
1452    int ret = 0;
1453    uint32_t offset = 0;
1454    void *buffer = NULL;
1455    void *entry_buffer;
1456    VHDXMetadataTableHeader *md_table;
1457    VHDXMetadataTableEntry  *md_table_entry;
1458
1459    /* Metadata entries */
1460    VHDXFileParameters     *mt_file_params;
1461    VHDXVirtualDiskSize    *mt_virtual_size;
1462    VHDXPage83Data         *mt_page83;
1463    VHDXVirtualDiskLogicalSectorSize  *mt_log_sector_size;
1464    VHDXVirtualDiskPhysicalSectorSize *mt_phys_sector_size;
1465
1466    entry_buffer = g_malloc0(VHDX_METADATA_ENTRY_BUFFER_SIZE);
1467
1468    mt_file_params = entry_buffer;
1469    offset += sizeof(VHDXFileParameters);
1470    mt_virtual_size = entry_buffer + offset;
1471    offset += sizeof(VHDXVirtualDiskSize);
1472    mt_page83 = entry_buffer + offset;
1473    offset += sizeof(VHDXPage83Data);
1474    mt_log_sector_size = entry_buffer + offset;
1475    offset += sizeof(VHDXVirtualDiskLogicalSectorSize);
1476    mt_phys_sector_size = entry_buffer + offset;
1477
1478    mt_file_params->block_size = cpu_to_le32(block_size);
1479    if (type == VHDX_TYPE_FIXED) {
1480        mt_file_params->data_bits |= VHDX_PARAMS_LEAVE_BLOCKS_ALLOCED;
1481        cpu_to_le32s(&mt_file_params->data_bits);
1482    }
1483
1484    vhdx_guid_generate(&mt_page83->page_83_data);
1485    cpu_to_leguids(&mt_page83->page_83_data);
1486    mt_virtual_size->virtual_disk_size        = cpu_to_le64(image_size);
1487    mt_log_sector_size->logical_sector_size   = cpu_to_le32(sector_size);
1488    mt_phys_sector_size->physical_sector_size = cpu_to_le32(sector_size);
1489
1490    buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1491    md_table = buffer;
1492
1493    md_table->signature   = VHDX_METADATA_SIGNATURE;
1494    md_table->entry_count = 5;
1495    vhdx_metadata_header_le_export(md_table);
1496
1497
1498    /* This will reference beyond the reserved table portion */
1499    offset = 64 * KiB;
1500
1501    md_table_entry = buffer + sizeof(VHDXMetadataTableHeader);
1502
1503    md_table_entry[0].item_id = file_param_guid;
1504    md_table_entry[0].offset  = offset;
1505    md_table_entry[0].length  = sizeof(VHDXFileParameters);
1506    md_table_entry[0].data_bits |= VHDX_META_FLAGS_IS_REQUIRED;
1507    offset += md_table_entry[0].length;
1508    vhdx_metadata_entry_le_export(&md_table_entry[0]);
1509
1510    md_table_entry[1].item_id = virtual_size_guid;
1511    md_table_entry[1].offset  = offset;
1512    md_table_entry[1].length  = sizeof(VHDXVirtualDiskSize);
1513    md_table_entry[1].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1514                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1515    offset += md_table_entry[1].length;
1516    vhdx_metadata_entry_le_export(&md_table_entry[1]);
1517
1518    md_table_entry[2].item_id = page83_guid;
1519    md_table_entry[2].offset  = offset;
1520    md_table_entry[2].length  = sizeof(VHDXPage83Data);
1521    md_table_entry[2].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1522                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1523    offset += md_table_entry[2].length;
1524    vhdx_metadata_entry_le_export(&md_table_entry[2]);
1525
1526    md_table_entry[3].item_id = logical_sector_guid;
1527    md_table_entry[3].offset  = offset;
1528    md_table_entry[3].length  = sizeof(VHDXVirtualDiskLogicalSectorSize);
1529    md_table_entry[3].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1530                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1531    offset += md_table_entry[3].length;
1532    vhdx_metadata_entry_le_export(&md_table_entry[3]);
1533
1534    md_table_entry[4].item_id = phys_sector_guid;
1535    md_table_entry[4].offset  = offset;
1536    md_table_entry[4].length  = sizeof(VHDXVirtualDiskPhysicalSectorSize);
1537    md_table_entry[4].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1538                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1539    vhdx_metadata_entry_le_export(&md_table_entry[4]);
1540
1541    ret = bdrv_pwrite(bs, metadata_offset, buffer, VHDX_HEADER_BLOCK_SIZE);
1542    if (ret < 0) {
1543        goto exit;
1544    }
1545
1546    ret = bdrv_pwrite(bs, metadata_offset + (64 * KiB), entry_buffer,
1547                      VHDX_METADATA_ENTRY_BUFFER_SIZE);
1548    if (ret < 0) {
1549        goto exit;
1550    }
1551
1552
1553exit:
1554    g_free(buffer);
1555    g_free(entry_buffer);
1556    return ret;
1557}
1558
1559/* This create the actual BAT itself.  We currently only support
1560 * 'Dynamic' and 'Fixed' image types.
1561 *
1562 *  Dynamic images: default state of the BAT is all zeroes.
1563 *
1564 *  Fixed images: default state of the BAT is fully populated, with
1565 *                file offsets and state PAYLOAD_BLOCK_FULLY_PRESENT.
1566 */
1567static int vhdx_create_bat(BlockDriverState *bs, BDRVVHDXState *s,
1568                           uint64_t image_size, VHDXImageType type,
1569                           bool use_zero_blocks, uint64_t file_offset,
1570                           uint32_t length)
1571{
1572    int ret = 0;
1573    uint64_t data_file_offset;
1574    uint64_t total_sectors = 0;
1575    uint64_t sector_num = 0;
1576    uint64_t unused;
1577    int block_state;
1578    VHDXSectorInfo sinfo;
1579
1580    assert(s->bat == NULL);
1581
1582    /* this gives a data start after BAT/bitmap entries, and well
1583     * past any metadata entries (with a 4 MB buffer for future
1584     * expansion */
1585    data_file_offset = file_offset + length + 5 * MiB;
1586    total_sectors = image_size >> s->logical_sector_size_bits;
1587
1588    if (type == VHDX_TYPE_DYNAMIC) {
1589        /* All zeroes, so we can just extend the file - the end of the BAT
1590         * is the furthest thing we have written yet */
1591        ret = bdrv_truncate(bs, data_file_offset);
1592        if (ret < 0) {
1593            goto exit;
1594        }
1595    } else if (type == VHDX_TYPE_FIXED) {
1596        ret = bdrv_truncate(bs, data_file_offset + image_size);
1597        if (ret < 0) {
1598            goto exit;
1599        }
1600    } else {
1601        ret = -ENOTSUP;
1602        goto exit;
1603    }
1604
1605    if (type == VHDX_TYPE_FIXED ||
1606                use_zero_blocks ||
1607                bdrv_has_zero_init(bs) == 0) {
1608        /* for a fixed file, the default BAT entry is not zero */
1609        s->bat = g_try_malloc0(length);
1610        if (length && s->bat == NULL) {
1611            ret = -ENOMEM;
1612            goto exit;
1613        }
1614        block_state = type == VHDX_TYPE_FIXED ? PAYLOAD_BLOCK_FULLY_PRESENT :
1615                                                PAYLOAD_BLOCK_NOT_PRESENT;
1616        block_state = use_zero_blocks ? PAYLOAD_BLOCK_ZERO : block_state;
1617        /* fill the BAT by emulating sector writes of sectors_per_block size */
1618        while (sector_num < total_sectors) {
1619            vhdx_block_translate(s, sector_num, s->sectors_per_block, &sinfo);
1620            sinfo.file_offset = data_file_offset +
1621                                (sector_num << s->logical_sector_size_bits);
1622            sinfo.file_offset = ROUND_UP(sinfo.file_offset, MiB);
1623            vhdx_update_bat_table_entry(bs, s, &sinfo, &unused, &unused,
1624                                        block_state);
1625            cpu_to_le64s(&s->bat[sinfo.bat_idx]);
1626            sector_num += s->sectors_per_block;
1627        }
1628        ret = bdrv_pwrite(bs, file_offset, s->bat, length);
1629        if (ret < 0) {
1630            goto exit;
1631        }
1632    }
1633
1634
1635
1636exit:
1637    g_free(s->bat);
1638    return ret;
1639}
1640
1641/* Creates the region table header, and region table entries.
1642 * There are 2 supported region table entries: BAT, and Metadata/
1643 *
1644 * As the calculations for the BAT region table are also needed
1645 * to create the BAT itself, we will also cause the BAT to be
1646 * created.
1647 */
1648static int vhdx_create_new_region_table(BlockDriverState *bs,
1649                                        uint64_t image_size,
1650                                        uint32_t block_size,
1651                                        uint32_t sector_size,
1652                                        uint32_t log_size,
1653                                        bool use_zero_blocks,
1654                                        VHDXImageType type,
1655                                        uint64_t *metadata_offset)
1656{
1657    int ret = 0;
1658    uint32_t offset = 0;
1659    void *buffer = NULL;
1660    uint64_t bat_file_offset;
1661    uint32_t bat_length;
1662    BDRVVHDXState *s = NULL;
1663    VHDXRegionTableHeader *region_table;
1664    VHDXRegionTableEntry *rt_bat;
1665    VHDXRegionTableEntry *rt_metadata;
1666
1667    assert(metadata_offset != NULL);
1668
1669    /* Populate enough of the BDRVVHDXState to be able to use the
1670     * pre-existing BAT calculation, translation, and update functions */
1671    s = g_new0(BDRVVHDXState, 1);
1672
1673    s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
1674                     (uint64_t) sector_size / (uint64_t) block_size;
1675
1676    s->sectors_per_block = block_size / sector_size;
1677    s->virtual_disk_size = image_size;
1678    s->block_size = block_size;
1679    s->logical_sector_size = sector_size;
1680
1681    vhdx_set_shift_bits(s);
1682
1683    vhdx_calc_bat_entries(s);
1684
1685    /* At this point the VHDX state is populated enough for creation */
1686
1687    /* a single buffer is used so we can calculate the checksum over the
1688     * entire 64KB block */
1689    buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1690    region_table = buffer;
1691    offset += sizeof(VHDXRegionTableHeader);
1692    rt_bat = buffer + offset;
1693    offset += sizeof(VHDXRegionTableEntry);
1694    rt_metadata  = buffer + offset;
1695
1696    region_table->signature = VHDX_REGION_SIGNATURE;
1697    region_table->entry_count = 2;   /* BAT and Metadata */
1698
1699    rt_bat->guid        = bat_guid;
1700    rt_bat->length      = ROUND_UP(s->bat_entries * sizeof(VHDXBatEntry), MiB);
1701    rt_bat->file_offset = ROUND_UP(VHDX_HEADER_SECTION_END + log_size, MiB);
1702    s->bat_offset = rt_bat->file_offset;
1703
1704    rt_metadata->guid        = metadata_guid;
1705    rt_metadata->file_offset = ROUND_UP(rt_bat->file_offset + rt_bat->length,
1706                                        MiB);
1707    rt_metadata->length      = 1 * MiB; /* min size, and more than enough */
1708    *metadata_offset = rt_metadata->file_offset;
1709
1710    bat_file_offset = rt_bat->file_offset;
1711    bat_length = rt_bat->length;
1712
1713    vhdx_region_header_le_export(region_table);
1714    vhdx_region_entry_le_export(rt_bat);
1715    vhdx_region_entry_le_export(rt_metadata);
1716
1717    vhdx_update_checksum(buffer, VHDX_HEADER_BLOCK_SIZE,
1718                         offsetof(VHDXRegionTableHeader, checksum));
1719
1720
1721    /* The region table gives us the data we need to create the BAT,
1722     * so do that now */
1723    ret = vhdx_create_bat(bs, s, image_size, type, use_zero_blocks,
1724                          bat_file_offset, bat_length);
1725    if (ret < 0) {
1726        goto exit;
1727    }
1728
1729    /* Now write out the region headers to disk */
1730    ret = bdrv_pwrite(bs, VHDX_REGION_TABLE_OFFSET, buffer,
1731                      VHDX_HEADER_BLOCK_SIZE);
1732    if (ret < 0) {
1733        goto exit;
1734    }
1735
1736    ret = bdrv_pwrite(bs, VHDX_REGION_TABLE2_OFFSET, buffer,
1737                      VHDX_HEADER_BLOCK_SIZE);
1738    if (ret < 0) {
1739        goto exit;
1740    }
1741
1742exit:
1743    g_free(s);
1744    g_free(buffer);
1745    return ret;
1746}
1747
1748/* We need to create the following elements:
1749 *
1750 *    .-----------------------------------------------------------------.
1751 *    |   (A)    |   (B)    |    (C)    |     (D)       |     (E)       |
1752 *    |  File ID |  Header1 |  Header 2 |  Region Tbl 1 |  Region Tbl 2 |
1753 *    |          |          |           |               |               |
1754 *    .-----------------------------------------------------------------.
1755 *    0         64KB      128KB       192KB           256KB           320KB
1756 *
1757 *
1758 *    .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1759 *    |     (F)     |     (G)       |    (H)    |                        |
1760 *    | Journal Log |  BAT / Bitmap |  Metadata |  .... data ......      |
1761 *    |             |               |           |                        |
1762 *    .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1763 *   1MB
1764 */
1765static int vhdx_create(const char *filename, QemuOpts *opts, Error **errp)
1766{
1767    int ret = 0;
1768    uint64_t image_size = (uint64_t) 2 * GiB;
1769    uint32_t log_size   = 1 * MiB;
1770    uint32_t block_size = 0;
1771    uint64_t signature;
1772    uint64_t metadata_offset;
1773    bool use_zero_blocks = false;
1774
1775    gunichar2 *creator = NULL;
1776    glong creator_items;
1777    BlockBackend *blk;
1778    char *type = NULL;
1779    VHDXImageType image_type;
1780    Error *local_err = NULL;
1781
1782    image_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
1783                          BDRV_SECTOR_SIZE);
1784    log_size = qemu_opt_get_size_del(opts, VHDX_BLOCK_OPT_LOG_SIZE, 0);
1785    block_size = qemu_opt_get_size_del(opts, VHDX_BLOCK_OPT_BLOCK_SIZE, 0);
1786    type = qemu_opt_get_del(opts, BLOCK_OPT_SUBFMT);
1787    use_zero_blocks = qemu_opt_get_bool_del(opts, VHDX_BLOCK_OPT_ZERO, true);
1788
1789    if (image_size > VHDX_MAX_IMAGE_SIZE) {
1790        error_setg_errno(errp, EINVAL, "Image size too large; max of 64TB");
1791        ret = -EINVAL;
1792        goto exit;
1793    }
1794
1795    if (type == NULL) {
1796        type = g_strdup("dynamic");
1797    }
1798
1799    if (!strcmp(type, "dynamic")) {
1800        image_type = VHDX_TYPE_DYNAMIC;
1801    } else if (!strcmp(type, "fixed")) {
1802        image_type = VHDX_TYPE_FIXED;
1803    } else if (!strcmp(type, "differencing")) {
1804        error_setg_errno(errp, ENOTSUP,
1805                         "Differencing files not yet supported");
1806        ret = -ENOTSUP;
1807        goto exit;
1808    } else {
1809        ret = -EINVAL;
1810        goto exit;
1811    }
1812
1813    /* These are pretty arbitrary, and mainly designed to keep the BAT
1814     * size reasonable to load into RAM */
1815    if (block_size == 0) {
1816        if (image_size > 32 * TiB) {
1817            block_size = 64 * MiB;
1818        } else if (image_size > (uint64_t) 100 * GiB) {
1819            block_size = 32 * MiB;
1820        } else if (image_size > 1 * GiB) {
1821            block_size = 16 * MiB;
1822        } else {
1823            block_size = 8 * MiB;
1824        }
1825    }
1826
1827
1828    /* make the log size close to what was specified, but must be
1829     * min 1MB, and multiple of 1MB */
1830    log_size = ROUND_UP(log_size, MiB);
1831
1832    block_size = ROUND_UP(block_size, MiB);
1833    block_size = block_size > VHDX_BLOCK_SIZE_MAX ? VHDX_BLOCK_SIZE_MAX :
1834                                                    block_size;
1835
1836    ret = bdrv_create_file(filename, opts, &local_err);
1837    if (ret < 0) {
1838        error_propagate(errp, local_err);
1839        goto exit;
1840    }
1841
1842    blk = blk_new_open(filename, NULL, NULL,
1843                       BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
1844    if (blk == NULL) {
1845        error_propagate(errp, local_err);
1846        ret = -EIO;
1847        goto exit;
1848    }
1849
1850    blk_set_allow_write_beyond_eof(blk, true);
1851
1852    /* Create (A) */
1853
1854    /* The creator field is optional, but may be useful for
1855     * debugging / diagnostics */
1856    creator = g_utf8_to_utf16("QEMU v" QEMU_VERSION, -1, NULL,
1857                              &creator_items, NULL);
1858    signature = cpu_to_le64(VHDX_FILE_SIGNATURE);
1859    ret = blk_pwrite(blk, VHDX_FILE_ID_OFFSET, &signature, sizeof(signature));
1860    if (ret < 0) {
1861        goto delete_and_exit;
1862    }
1863    if (creator) {
1864        ret = blk_pwrite(blk, VHDX_FILE_ID_OFFSET + sizeof(signature),
1865                         creator, creator_items * sizeof(gunichar2));
1866        if (ret < 0) {
1867            goto delete_and_exit;
1868        }
1869    }
1870
1871
1872    /* Creates (B),(C) */
1873    ret = vhdx_create_new_headers(blk_bs(blk), image_size, log_size);
1874    if (ret < 0) {
1875        goto delete_and_exit;
1876    }
1877
1878    /* Creates (D),(E),(G) explicitly. (F) created as by-product */
1879    ret = vhdx_create_new_region_table(blk_bs(blk), image_size, block_size, 512,
1880                                       log_size, use_zero_blocks, image_type,
1881                                       &metadata_offset);
1882    if (ret < 0) {
1883        goto delete_and_exit;
1884    }
1885
1886    /* Creates (H) */
1887    ret = vhdx_create_new_metadata(blk_bs(blk), image_size, block_size, 512,
1888                                   metadata_offset, image_type);
1889    if (ret < 0) {
1890        goto delete_and_exit;
1891    }
1892
1893
1894delete_and_exit:
1895    blk_unref(blk);
1896exit:
1897    g_free(type);
1898    g_free(creator);
1899    return ret;
1900}
1901
1902/* If opened r/w, the VHDX driver will automatically replay the log,
1903 * if one is present, inside the vhdx_open() call.
1904 *
1905 * If qemu-img check -r all is called, the image is automatically opened
1906 * r/w and any log has already been replayed, so there is nothing (currently)
1907 * for us to do here
1908 */
1909static int vhdx_check(BlockDriverState *bs, BdrvCheckResult *result,
1910                       BdrvCheckMode fix)
1911{
1912    BDRVVHDXState *s = bs->opaque;
1913
1914    if (s->log_replayed_on_open) {
1915        result->corruptions_fixed++;
1916    }
1917    return 0;
1918}
1919
1920static QemuOptsList vhdx_create_opts = {
1921    .name = "vhdx-create-opts",
1922    .head = QTAILQ_HEAD_INITIALIZER(vhdx_create_opts.head),
1923    .desc = {
1924        {
1925           .name = BLOCK_OPT_SIZE,
1926           .type = QEMU_OPT_SIZE,
1927           .help = "Virtual disk size; max of 64TB."
1928       },
1929       {
1930           .name = VHDX_BLOCK_OPT_LOG_SIZE,
1931           .type = QEMU_OPT_SIZE,
1932           .def_value_str = stringify(DEFAULT_LOG_SIZE),
1933           .help = "Log size; min 1MB."
1934       },
1935       {
1936           .name = VHDX_BLOCK_OPT_BLOCK_SIZE,
1937           .type = QEMU_OPT_SIZE,
1938           .def_value_str = stringify(0),
1939           .help = "Block Size; min 1MB, max 256MB. " \
1940                   "0 means auto-calculate based on image size."
1941       },
1942       {
1943           .name = BLOCK_OPT_SUBFMT,
1944           .type = QEMU_OPT_STRING,
1945           .help = "VHDX format type, can be either 'dynamic' or 'fixed'. "\
1946                   "Default is 'dynamic'."
1947       },
1948       {
1949           .name = VHDX_BLOCK_OPT_ZERO,
1950           .type = QEMU_OPT_BOOL,
1951           .help = "Force use of payload blocks of type 'ZERO'. "\
1952                   "Non-standard, but default.  Do not set to 'off' when "\
1953                   "using 'qemu-img convert' with subformat=dynamic."
1954       },
1955       { NULL }
1956    }
1957};
1958
1959static BlockDriver bdrv_vhdx = {
1960    .format_name            = "vhdx",
1961    .instance_size          = sizeof(BDRVVHDXState),
1962    .bdrv_probe             = vhdx_probe,
1963    .bdrv_open              = vhdx_open,
1964    .bdrv_close             = vhdx_close,
1965    .bdrv_reopen_prepare    = vhdx_reopen_prepare,
1966    .bdrv_co_readv          = vhdx_co_readv,
1967    .bdrv_co_writev         = vhdx_co_writev,
1968    .bdrv_create            = vhdx_create,
1969    .bdrv_get_info          = vhdx_get_info,
1970    .bdrv_check             = vhdx_check,
1971    .bdrv_has_zero_init     = bdrv_has_zero_init_1,
1972
1973    .create_opts            = &vhdx_create_opts,
1974};
1975
1976static void bdrv_vhdx_init(void)
1977{
1978    bdrv_register(&bdrv_vhdx);
1979}
1980
1981block_init(bdrv_vhdx_init);
1982