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 "block/block_int.h"
  21#include "block/qdict.h"
  22#include "sysemu/block-backend.h"
  23#include "qemu/module.h"
  24#include "qemu/option.h"
  25#include "qemu/crc32c.h"
  26#include "qemu/bswap.h"
  27#include "vhdx.h"
  28#include "migration/blocker.h"
  29#include "qemu/uuid.h"
  30#include "qapi/qmp/qdict.h"
  31#include "qapi/qobject-input-visitor.h"
  32#include "qapi/qapi-visit-block-core.h"
  33
  34/* Options for VHDX creation */
  35
  36#define VHDX_BLOCK_OPT_LOG_SIZE   "log_size"
  37#define VHDX_BLOCK_OPT_BLOCK_SIZE "block_size"
  38#define VHDX_BLOCK_OPT_ZERO "block_state_zero"
  39
  40typedef enum VHDXImageType {
  41    VHDX_TYPE_DYNAMIC = 0,
  42    VHDX_TYPE_FIXED,
  43    VHDX_TYPE_DIFFERENCING,   /* Currently unsupported */
  44} VHDXImageType;
  45
  46static QemuOptsList vhdx_create_opts;
  47
  48/* Several metadata and region table data entries are identified by
  49 * guids in  a MS-specific GUID format. */
  50
  51
  52/* ------- Known Region Table GUIDs ---------------------- */
  53static const MSGUID bat_guid =      { .data1 = 0x2dc27766,
  54                                      .data2 = 0xf623,
  55                                      .data3 = 0x4200,
  56                                      .data4 = { 0x9d, 0x64, 0x11, 0x5e,
  57                                                 0x9b, 0xfd, 0x4a, 0x08} };
  58
  59static const MSGUID metadata_guid = { .data1 = 0x8b7ca206,
  60                                      .data2 = 0x4790,
  61                                      .data3 = 0x4b9a,
  62                                      .data4 = { 0xb8, 0xfe, 0x57, 0x5f,
  63                                                 0x05, 0x0f, 0x88, 0x6e} };
  64
  65
  66
  67/* ------- Known Metadata Entry GUIDs ---------------------- */
  68static const MSGUID file_param_guid =   { .data1 = 0xcaa16737,
  69                                          .data2 = 0xfa36,
  70                                          .data3 = 0x4d43,
  71                                          .data4 = { 0xb3, 0xb6, 0x33, 0xf0,
  72                                                     0xaa, 0x44, 0xe7, 0x6b} };
  73
  74static const MSGUID virtual_size_guid = { .data1 = 0x2FA54224,
  75                                          .data2 = 0xcd1b,
  76                                          .data3 = 0x4876,
  77                                          .data4 = { 0xb2, 0x11, 0x5d, 0xbe,
  78                                                     0xd8, 0x3b, 0xf4, 0xb8} };
  79
  80static const MSGUID page83_guid =       { .data1 = 0xbeca12ab,
  81                                          .data2 = 0xb2e6,
  82                                          .data3 = 0x4523,
  83                                          .data4 = { 0x93, 0xef, 0xc3, 0x09,
  84                                                     0xe0, 0x00, 0xc7, 0x46} };
  85
  86
  87static const MSGUID phys_sector_guid =  { .data1 = 0xcda348c7,
  88                                          .data2 = 0x445d,
  89                                          .data3 = 0x4471,
  90                                          .data4 = { 0x9c, 0xc9, 0xe9, 0x88,
  91                                                     0x52, 0x51, 0xc5, 0x56} };
  92
  93static const MSGUID parent_locator_guid = { .data1 = 0xa8d35f2d,
  94                                            .data2 = 0xb30b,
  95                                            .data3 = 0x454d,
  96                                            .data4 = { 0xab, 0xf7, 0xd3,
  97                                                       0xd8, 0x48, 0x34,
  98                                                       0xab, 0x0c} };
  99
 100static const MSGUID logical_sector_guid = { .data1 = 0x8141bf1d,
 101                                            .data2 = 0xa96f,
 102                                            .data3 = 0x4709,
 103                                            .data4 = { 0xba, 0x47, 0xf2,
 104                                                       0x33, 0xa8, 0xfa,
 105                                                       0xab, 0x5f} };
 106
 107/* Each parent type must have a valid GUID; this is for parent images
 108 * of type 'VHDX'.  If we were to allow e.g. a QCOW2 parent, we would
 109 * need to make up our own QCOW2 GUID type */
 110static const MSGUID parent_vhdx_guid __attribute__((unused))
 111                                     = { .data1 = 0xb04aefb7,
 112                                         .data2 = 0xd19e,
 113                                         .data3 = 0x4a81,
 114                                         .data4 = { 0xb7, 0x89, 0x25, 0xb8,
 115                                                    0xe9, 0x44, 0x59, 0x13} };
 116
 117
 118#define META_FILE_PARAMETER_PRESENT      0x01
 119#define META_VIRTUAL_DISK_SIZE_PRESENT   0x02
 120#define META_PAGE_83_PRESENT             0x04
 121#define META_LOGICAL_SECTOR_SIZE_PRESENT 0x08
 122#define META_PHYS_SECTOR_SIZE_PRESENT    0x10
 123#define META_PARENT_LOCATOR_PRESENT      0x20
 124
 125#define META_ALL_PRESENT    \
 126    (META_FILE_PARAMETER_PRESENT | META_VIRTUAL_DISK_SIZE_PRESENT | \
 127     META_PAGE_83_PRESENT | META_LOGICAL_SECTOR_SIZE_PRESENT | \
 128     META_PHYS_SECTOR_SIZE_PRESENT)
 129
 130
 131typedef struct VHDXSectorInfo {
 132    uint32_t bat_idx;       /* BAT entry index */
 133    uint32_t sectors_avail; /* sectors available in payload block */
 134    uint32_t bytes_left;    /* bytes left in the block after data to r/w */
 135    uint32_t bytes_avail;   /* bytes available in payload block */
 136    uint64_t file_offset;   /* absolute offset in bytes, in file */
 137    uint64_t block_offset;  /* block offset, in bytes */
 138} VHDXSectorInfo;
 139
 140/* Calculates new checksum.
 141 *
 142 * Zero is substituted during crc calculation for the original crc field
 143 * crc_offset: byte offset in buf of the buffer crc
 144 * buf: buffer pointer
 145 * size: size of buffer (must be > crc_offset+4)
 146 *
 147 * Note: The buffer should have all multi-byte data in little-endian format,
 148 *       and the resulting checksum is in little endian format.
 149 */
 150uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset)
 151{
 152    uint32_t crc;
 153
 154    assert(buf != NULL);
 155    assert(size > (crc_offset + sizeof(crc)));
 156
 157    memset(buf + crc_offset, 0, sizeof(crc));
 158    crc =  crc32c(0xffffffff, buf, size);
 159    crc = cpu_to_le32(crc);
 160    memcpy(buf + crc_offset, &crc, sizeof(crc));
 161
 162    return crc;
 163}
 164
 165uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
 166                            int crc_offset)
 167{
 168    uint32_t crc_new;
 169    uint32_t crc_orig;
 170    assert(buf != NULL);
 171
 172    if (crc_offset > 0) {
 173        memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
 174        memset(buf + crc_offset, 0, sizeof(crc_orig));
 175    }
 176
 177    crc_new = crc32c(crc, buf, size);
 178    if (crc_offset > 0) {
 179        memcpy(buf + crc_offset, &crc_orig, sizeof(crc_orig));
 180    }
 181
 182    return crc_new;
 183}
 184
 185/* Validates the checksum of the buffer, with an in-place CRC.
 186 *
 187 * Zero is substituted during crc calculation for the original crc field,
 188 * and the crc field is restored afterwards.  But the buffer will be modified
 189 * during the calculation, so this may not be not suitable for multi-threaded
 190 * use.
 191 *
 192 * crc_offset: byte offset in buf of the buffer crc
 193 * buf: buffer pointer
 194 * size: size of buffer (must be > crc_offset+4)
 195 *
 196 * returns true if checksum is valid, false otherwise
 197 */
 198bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset)
 199{
 200    uint32_t crc_orig;
 201    uint32_t crc;
 202
 203    assert(buf != NULL);
 204    assert(size > (crc_offset + 4));
 205
 206    memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
 207    crc_orig = le32_to_cpu(crc_orig);
 208
 209    crc = vhdx_checksum_calc(0xffffffff, buf, size, crc_offset);
 210
 211    return crc == crc_orig;
 212}
 213
 214
 215/*
 216 * This generates a UUID that is compliant with the MS GUIDs used
 217 * in the VHDX spec (and elsewhere).
 218 */
 219void vhdx_guid_generate(MSGUID *guid)
 220{
 221    QemuUUID uuid;
 222    assert(guid != NULL);
 223
 224    qemu_uuid_generate(&uuid);
 225    memcpy(guid, &uuid, sizeof(MSGUID));
 226}
 227
 228/* Check for region overlaps inside the VHDX image */
 229static int vhdx_region_check(BDRVVHDXState *s, uint64_t start, uint64_t length)
 230{
 231    int ret = 0;
 232    uint64_t end;
 233    VHDXRegionEntry *r;
 234
 235    end = start + length;
 236    QLIST_FOREACH(r, &s->regions, entries) {
 237        if (!((start >= r->end) || (end <= r->start))) {
 238            ret = -EINVAL;
 239            goto exit;
 240        }
 241    }
 242
 243exit:
 244    return ret;
 245}
 246
 247/* Register a region for future checks */
 248static void vhdx_region_register(BDRVVHDXState *s,
 249                                 uint64_t start, uint64_t length)
 250{
 251    VHDXRegionEntry *r;
 252
 253    r = g_malloc0(sizeof(*r));
 254
 255    r->start = start;
 256    r->end = start + length;
 257
 258    QLIST_INSERT_HEAD(&s->regions, r, entries);
 259}
 260
 261/* Free all registered regions */
 262static void vhdx_region_unregister_all(BDRVVHDXState *s)
 263{
 264    VHDXRegionEntry *r, *r_next;
 265
 266    QLIST_FOREACH_SAFE(r, &s->regions, entries, r_next) {
 267        QLIST_REMOVE(r, entries);
 268        g_free(r);
 269    }
 270}
 271
 272static void vhdx_set_shift_bits(BDRVVHDXState *s)
 273{
 274    s->logical_sector_size_bits = ctz32(s->logical_sector_size);
 275    s->sectors_per_block_bits =   ctz32(s->sectors_per_block);
 276    s->chunk_ratio_bits =         ctz64(s->chunk_ratio);
 277    s->block_size_bits =          ctz32(s->block_size);
 278}
 279
 280/*
 281 * Per the MS VHDX Specification, for every VHDX file:
 282 *      - The header section is fixed size - 1 MB
 283 *      - The header section is always the first "object"
 284 *      - The first 64KB of the header is the File Identifier
 285 *      - The first uint64 (8 bytes) is the VHDX Signature ("vhdxfile")
 286 *      - The following 512 bytes constitute a UTF-16 string identifiying the
 287 *        software that created the file, and is optional and diagnostic only.
 288 *
 289 *  Therefore, we probe by looking for the vhdxfile signature "vhdxfile"
 290 */
 291static int vhdx_probe(const uint8_t *buf, int buf_size, const char *filename)
 292{
 293    if (buf_size >= 8 && !memcmp(buf, "vhdxfile", 8)) {
 294        return 100;
 295    }
 296    return 0;
 297}
 298
 299/*
 300 * Writes the header to the specified offset.
 301 *
 302 * This will optionally read in buffer data from disk (otherwise zero-fill),
 303 * and then update the header checksum.  Header is converted to proper
 304 * endianness before being written to the specified file offset
 305 */
 306static int vhdx_write_header(BdrvChild *file, VHDXHeader *hdr,
 307                             uint64_t offset, bool read)
 308{
 309    BlockDriverState *bs_file = file->bs;
 310    uint8_t *buffer = NULL;
 311    int ret;
 312    VHDXHeader *header_le;
 313
 314    assert(bs_file != NULL);
 315    assert(hdr != NULL);
 316
 317    /* the header checksum is not over just the packed size of VHDXHeader,
 318     * but rather over the entire 'reserved' range for the header, which is
 319     * 4KB (VHDX_HEADER_SIZE). */
 320
 321    buffer = qemu_blockalign(bs_file, VHDX_HEADER_SIZE);
 322    if (read) {
 323        /* if true, we can't assume the extra reserved bytes are 0 */
 324        ret = bdrv_pread(file, offset, buffer, VHDX_HEADER_SIZE);
 325        if (ret < 0) {
 326            goto exit;
 327        }
 328    } else {
 329        memset(buffer, 0, VHDX_HEADER_SIZE);
 330    }
 331
 332    /* overwrite the actual VHDXHeader portion */
 333    header_le = (VHDXHeader *)buffer;
 334    memcpy(header_le, hdr, sizeof(VHDXHeader));
 335    vhdx_header_le_export(hdr, header_le);
 336    vhdx_update_checksum(buffer, VHDX_HEADER_SIZE,
 337                         offsetof(VHDXHeader, checksum));
 338    ret = bdrv_pwrite_sync(file, offset, header_le, sizeof(VHDXHeader));
 339
 340exit:
 341    qemu_vfree(buffer);
 342    return ret;
 343}
 344
 345/* Update the VHDX headers
 346 *
 347 * This follows the VHDX spec procedures for header updates.
 348 *
 349 *  - non-current header is updated with largest sequence number
 350 */
 351static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s,
 352                              bool generate_data_write_guid, MSGUID *log_guid)
 353{
 354    int ret = 0;
 355    int hdr_idx = 0;
 356    uint64_t header_offset = VHDX_HEADER1_OFFSET;
 357
 358    VHDXHeader *active_header;
 359    VHDXHeader *inactive_header;
 360
 361    /* operate on the non-current header */
 362    if (s->curr_header == 0) {
 363        hdr_idx = 1;
 364        header_offset = VHDX_HEADER2_OFFSET;
 365    }
 366
 367    active_header   = s->headers[s->curr_header];
 368    inactive_header = s->headers[hdr_idx];
 369
 370    inactive_header->sequence_number = active_header->sequence_number + 1;
 371
 372    /* a new file guid must be generated before any file write, including
 373     * headers */
 374    inactive_header->file_write_guid = s->session_guid;
 375
 376    /* a new data guid only needs to be generated before any guest-visible
 377     * writes (i.e. something observable via virtual disk read) */
 378    if (generate_data_write_guid) {
 379        vhdx_guid_generate(&inactive_header->data_write_guid);
 380    }
 381
 382    /* update the log guid if present */
 383    if (log_guid) {
 384        inactive_header->log_guid = *log_guid;
 385    }
 386
 387    ret = vhdx_write_header(bs->file, inactive_header, header_offset, true);
 388    if (ret < 0) {
 389        goto exit;
 390    }
 391    s->curr_header = hdr_idx;
 392
 393exit:
 394    return ret;
 395}
 396
 397/*
 398 * The VHDX spec calls for header updates to be performed twice, so that both
 399 * the current and non-current header have valid info
 400 */
 401int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s,
 402                        bool generate_data_write_guid, MSGUID *log_guid)
 403{
 404    int ret;
 405
 406    ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
 407    if (ret < 0) {
 408        return ret;
 409    }
 410    ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
 411    return ret;
 412}
 413
 414/* opens the specified header block from the VHDX file header section */
 415static void vhdx_parse_header(BlockDriverState *bs, BDRVVHDXState *s,
 416                              Error **errp)
 417{
 418    int ret;
 419    VHDXHeader *header1;
 420    VHDXHeader *header2;
 421    bool h1_valid = false;
 422    bool h2_valid = false;
 423    uint64_t h1_seq = 0;
 424    uint64_t h2_seq = 0;
 425    uint8_t *buffer;
 426
 427    /* header1 & header2 are freed in vhdx_close() */
 428    header1 = qemu_blockalign(bs, sizeof(VHDXHeader));
 429    header2 = qemu_blockalign(bs, sizeof(VHDXHeader));
 430
 431    buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE);
 432
 433    s->headers[0] = header1;
 434    s->headers[1] = header2;
 435
 436    /* We have to read the whole VHDX_HEADER_SIZE instead of
 437     * sizeof(VHDXHeader), because the checksum is over the whole
 438     * region */
 439    ret = bdrv_pread(bs->file, VHDX_HEADER1_OFFSET, buffer,
 440                     VHDX_HEADER_SIZE);
 441    if (ret < 0) {
 442        goto fail;
 443    }
 444    /* copy over just the relevant portion that we need */
 445    memcpy(header1, buffer, sizeof(VHDXHeader));
 446
 447    if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4)) {
 448        vhdx_header_le_import(header1);
 449        if (header1->signature == VHDX_HEADER_SIGNATURE &&
 450            header1->version == 1) {
 451            h1_seq = header1->sequence_number;
 452            h1_valid = true;
 453        }
 454    }
 455
 456    ret = bdrv_pread(bs->file, VHDX_HEADER2_OFFSET, buffer,
 457                     VHDX_HEADER_SIZE);
 458    if (ret < 0) {
 459        goto fail;
 460    }
 461    /* copy over just the relevant portion that we need */
 462    memcpy(header2, buffer, sizeof(VHDXHeader));
 463
 464    if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4)) {
 465        vhdx_header_le_import(header2);
 466        if (header2->signature == VHDX_HEADER_SIGNATURE &&
 467            header2->version == 1) {
 468            h2_seq = header2->sequence_number;
 469            h2_valid = true;
 470        }
 471    }
 472
 473    /* If there is only 1 valid header (or no valid headers), we
 474     * don't care what the sequence numbers are */
 475    if (h1_valid && !h2_valid) {
 476        s->curr_header = 0;
 477    } else if (!h1_valid && h2_valid) {
 478        s->curr_header = 1;
 479    } else if (!h1_valid && !h2_valid) {
 480        goto fail;
 481    } else {
 482        /* If both headers are valid, then we choose the active one by the
 483         * highest sequence number.  If the sequence numbers are equal, that is
 484         * invalid */
 485        if (h1_seq > h2_seq) {
 486            s->curr_header = 0;
 487        } else if (h2_seq > h1_seq) {
 488            s->curr_header = 1;
 489        } else {
 490            /* The Microsoft Disk2VHD tool will create 2 identical
 491             * headers, with identical sequence numbers.  If the headers are
 492             * identical, don't consider the file corrupt */
 493            if (!memcmp(header1, header2, sizeof(VHDXHeader))) {
 494                s->curr_header = 0;
 495            } else {
 496                goto fail;
 497            }
 498        }
 499    }
 500
 501    vhdx_region_register(s, s->headers[s->curr_header]->log_offset,
 502                            s->headers[s->curr_header]->log_length);
 503    goto exit;
 504
 505fail:
 506    error_setg_errno(errp, -ret, "No valid VHDX header found");
 507    qemu_vfree(header1);
 508    qemu_vfree(header2);
 509    s->headers[0] = NULL;
 510    s->headers[1] = NULL;
 511exit:
 512    qemu_vfree(buffer);
 513}
 514
 515
 516static int vhdx_open_region_tables(BlockDriverState *bs, BDRVVHDXState *s)
 517{
 518    int ret = 0;
 519    uint8_t *buffer;
 520    int offset = 0;
 521    VHDXRegionTableEntry rt_entry;
 522    uint32_t i;
 523    bool bat_rt_found = false;
 524    bool metadata_rt_found = false;
 525
 526    /* We have to read the whole 64KB block, because the crc32 is over the
 527     * whole block */
 528    buffer = qemu_blockalign(bs, VHDX_HEADER_BLOCK_SIZE);
 529
 530    ret = bdrv_pread(bs->file, VHDX_REGION_TABLE_OFFSET, buffer,
 531                     VHDX_HEADER_BLOCK_SIZE);
 532    if (ret < 0) {
 533        goto fail;
 534    }
 535    memcpy(&s->rt, buffer, sizeof(s->rt));
 536    offset += sizeof(s->rt);
 537
 538    if (!vhdx_checksum_is_valid(buffer, VHDX_HEADER_BLOCK_SIZE, 4)) {
 539        ret = -EINVAL;
 540        goto fail;
 541    }
 542
 543    vhdx_region_header_le_import(&s->rt);
 544
 545    if (s->rt.signature != VHDX_REGION_SIGNATURE) {
 546        ret = -EINVAL;
 547        goto fail;
 548    }
 549
 550
 551    /* Per spec, maximum region table entry count is 2047 */
 552    if (s->rt.entry_count > 2047) {
 553        ret = -EINVAL;
 554        goto fail;
 555    }
 556
 557    for (i = 0; i < s->rt.entry_count; i++) {
 558        memcpy(&rt_entry, buffer + offset, sizeof(rt_entry));
 559        offset += sizeof(rt_entry);
 560
 561        vhdx_region_entry_le_import(&rt_entry);
 562
 563        /* check for region overlap between these entries, and any
 564         * other memory regions in the file */
 565        ret = vhdx_region_check(s, rt_entry.file_offset, rt_entry.length);
 566        if (ret < 0) {
 567            goto fail;
 568        }
 569
 570        vhdx_region_register(s, rt_entry.file_offset, rt_entry.length);
 571
 572        /* see if we recognize the entry */
 573        if (guid_eq(rt_entry.guid, bat_guid)) {
 574            /* must be unique; if we have already found it this is invalid */
 575            if (bat_rt_found) {
 576                ret = -EINVAL;
 577                goto fail;
 578            }
 579            bat_rt_found = true;
 580            s->bat_rt = rt_entry;
 581            continue;
 582        }
 583
 584        if (guid_eq(rt_entry.guid, metadata_guid)) {
 585            /* must be unique; if we have already found it this is invalid */
 586            if (metadata_rt_found) {
 587                ret = -EINVAL;
 588                goto fail;
 589            }
 590            metadata_rt_found = true;
 591            s->metadata_rt = rt_entry;
 592            continue;
 593        }
 594
 595        if (rt_entry.data_bits & VHDX_REGION_ENTRY_REQUIRED) {
 596            /* cannot read vhdx file - required region table entry that
 597             * we do not understand.  per spec, we must fail to open */
 598            ret = -ENOTSUP;
 599            goto fail;
 600        }
 601    }
 602
 603    if (!bat_rt_found || !metadata_rt_found) {
 604        ret = -EINVAL;
 605        goto fail;
 606    }
 607
 608    ret = 0;
 609
 610fail:
 611    qemu_vfree(buffer);
 612    return ret;
 613}
 614
 615
 616
 617/* Metadata initial parser
 618 *
 619 * This loads all the metadata entry fields.  This may cause additional
 620 * fields to be processed (e.g. parent locator, etc..).
 621 *
 622 * There are 5 Metadata items that are always required:
 623 *      - File Parameters (block size, has a parent)
 624 *      - Virtual Disk Size (size, in bytes, of the virtual drive)
 625 *      - Page 83 Data (scsi page 83 guid)
 626 *      - Logical Sector Size (logical sector size in bytes, either 512 or
 627 *                             4096.  We only support 512 currently)
 628 *      - Physical Sector Size (512 or 4096)
 629 *
 630 * Also, if the File Parameters indicate this is a differencing file,
 631 * we must also look for the Parent Locator metadata item.
 632 */
 633static int vhdx_parse_metadata(BlockDriverState *bs, BDRVVHDXState *s)
 634{
 635    int ret = 0;
 636    uint8_t *buffer;
 637    int offset = 0;
 638    uint32_t i = 0;
 639    VHDXMetadataTableEntry md_entry;
 640
 641    buffer = qemu_blockalign(bs, VHDX_METADATA_TABLE_MAX_SIZE);
 642
 643    ret = bdrv_pread(bs->file, s->metadata_rt.file_offset, buffer,
 644                     VHDX_METADATA_TABLE_MAX_SIZE);
 645    if (ret < 0) {
 646        goto exit;
 647    }
 648    memcpy(&s->metadata_hdr, buffer, sizeof(s->metadata_hdr));
 649    offset += sizeof(s->metadata_hdr);
 650
 651    vhdx_metadata_header_le_import(&s->metadata_hdr);
 652
 653    if (s->metadata_hdr.signature != VHDX_METADATA_SIGNATURE) {
 654        ret = -EINVAL;
 655        goto exit;
 656    }
 657
 658    s->metadata_entries.present = 0;
 659
 660    if ((s->metadata_hdr.entry_count * sizeof(md_entry)) >
 661        (VHDX_METADATA_TABLE_MAX_SIZE - offset)) {
 662        ret = -EINVAL;
 663        goto exit;
 664    }
 665
 666    for (i = 0; i < s->metadata_hdr.entry_count; i++) {
 667        memcpy(&md_entry, buffer + offset, sizeof(md_entry));
 668        offset += sizeof(md_entry);
 669
 670        vhdx_metadata_entry_le_import(&md_entry);
 671
 672        if (guid_eq(md_entry.item_id, file_param_guid)) {
 673            if (s->metadata_entries.present & META_FILE_PARAMETER_PRESENT) {
 674                ret = -EINVAL;
 675                goto exit;
 676            }
 677            s->metadata_entries.file_parameters_entry = md_entry;
 678            s->metadata_entries.present |= META_FILE_PARAMETER_PRESENT;
 679            continue;
 680        }
 681
 682        if (guid_eq(md_entry.item_id, virtual_size_guid)) {
 683            if (s->metadata_entries.present & META_VIRTUAL_DISK_SIZE_PRESENT) {
 684                ret = -EINVAL;
 685                goto exit;
 686            }
 687            s->metadata_entries.virtual_disk_size_entry = md_entry;
 688            s->metadata_entries.present |= META_VIRTUAL_DISK_SIZE_PRESENT;
 689            continue;
 690        }
 691
 692        if (guid_eq(md_entry.item_id, page83_guid)) {
 693            if (s->metadata_entries.present & META_PAGE_83_PRESENT) {
 694                ret = -EINVAL;
 695                goto exit;
 696            }
 697            s->metadata_entries.page83_data_entry = md_entry;
 698            s->metadata_entries.present |= META_PAGE_83_PRESENT;
 699            continue;
 700        }
 701
 702        if (guid_eq(md_entry.item_id, logical_sector_guid)) {
 703            if (s->metadata_entries.present &
 704                META_LOGICAL_SECTOR_SIZE_PRESENT) {
 705                ret = -EINVAL;
 706                goto exit;
 707            }
 708            s->metadata_entries.logical_sector_size_entry = md_entry;
 709            s->metadata_entries.present |= META_LOGICAL_SECTOR_SIZE_PRESENT;
 710            continue;
 711        }
 712
 713        if (guid_eq(md_entry.item_id, phys_sector_guid)) {
 714            if (s->metadata_entries.present & META_PHYS_SECTOR_SIZE_PRESENT) {
 715                ret = -EINVAL;
 716                goto exit;
 717            }
 718            s->metadata_entries.phys_sector_size_entry = md_entry;
 719            s->metadata_entries.present |= META_PHYS_SECTOR_SIZE_PRESENT;
 720            continue;
 721        }
 722
 723        if (guid_eq(md_entry.item_id, parent_locator_guid)) {
 724            if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
 725                ret = -EINVAL;
 726                goto exit;
 727            }
 728            s->metadata_entries.parent_locator_entry = md_entry;
 729            s->metadata_entries.present |= META_PARENT_LOCATOR_PRESENT;
 730            continue;
 731        }
 732
 733        if (md_entry.data_bits & VHDX_META_FLAGS_IS_REQUIRED) {
 734            /* cannot read vhdx file - required region table entry that
 735             * we do not understand.  per spec, we must fail to open */
 736            ret = -ENOTSUP;
 737            goto exit;
 738        }
 739    }
 740
 741    if (s->metadata_entries.present != META_ALL_PRESENT) {
 742        ret = -ENOTSUP;
 743        goto exit;
 744    }
 745
 746    ret = bdrv_pread(bs->file,
 747                     s->metadata_entries.file_parameters_entry.offset
 748                                         + s->metadata_rt.file_offset,
 749                     &s->params,
 750                     sizeof(s->params));
 751
 752    if (ret < 0) {
 753        goto exit;
 754    }
 755
 756    s->params.block_size = le32_to_cpu(s->params.block_size);
 757    s->params.data_bits = le32_to_cpu(s->params.data_bits);
 758
 759
 760    /* We now have the file parameters, so we can tell if this is a
 761     * differencing file (i.e.. has_parent), is dynamic or fixed
 762     * sized (leave_blocks_allocated), and the block size */
 763
 764    /* The parent locator required iff the file parameters has_parent set */
 765    if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
 766        if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
 767            /* TODO: parse  parent locator fields */
 768            ret = -ENOTSUP; /* temp, until differencing files are supported */
 769            goto exit;
 770        } else {
 771            /* if has_parent is set, but there is not parent locator present,
 772             * then that is an invalid combination */
 773            ret = -EINVAL;
 774            goto exit;
 775        }
 776    }
 777
 778    /* determine virtual disk size, logical sector size,
 779     * and phys sector size */
 780
 781    ret = bdrv_pread(bs->file,
 782                     s->metadata_entries.virtual_disk_size_entry.offset
 783                                           + s->metadata_rt.file_offset,
 784                     &s->virtual_disk_size,
 785                     sizeof(uint64_t));
 786    if (ret < 0) {
 787        goto exit;
 788    }
 789    ret = bdrv_pread(bs->file,
 790                     s->metadata_entries.logical_sector_size_entry.offset
 791                                             + s->metadata_rt.file_offset,
 792                     &s->logical_sector_size,
 793                     sizeof(uint32_t));
 794    if (ret < 0) {
 795        goto exit;
 796    }
 797    ret = bdrv_pread(bs->file,
 798                     s->metadata_entries.phys_sector_size_entry.offset
 799                                          + s->metadata_rt.file_offset,
 800                     &s->physical_sector_size,
 801                     sizeof(uint32_t));
 802    if (ret < 0) {
 803        goto exit;
 804    }
 805
 806    s->virtual_disk_size = le64_to_cpu(s->virtual_disk_size);
 807    s->logical_sector_size = le32_to_cpu(s->logical_sector_size);
 808    s->physical_sector_size = le32_to_cpu(s->physical_sector_size);
 809
 810    if (s->params.block_size < VHDX_BLOCK_SIZE_MIN ||
 811        s->params.block_size > VHDX_BLOCK_SIZE_MAX) {
 812        ret = -EINVAL;
 813        goto exit;
 814    }
 815
 816    /* only 2 supported sector sizes */
 817    if (s->logical_sector_size != 512 && s->logical_sector_size != 4096) {
 818        ret = -EINVAL;
 819        goto exit;
 820    }
 821
 822    /* Both block_size and sector_size are guaranteed powers of 2, below.
 823       Due to range checks above, s->sectors_per_block can never be < 256 */
 824    s->sectors_per_block = s->params.block_size / s->logical_sector_size;
 825    s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
 826                     (uint64_t)s->logical_sector_size /
 827                     (uint64_t)s->params.block_size;
 828
 829    /* These values are ones we will want to use for division / multiplication
 830     * later on, and they are all guaranteed (per the spec) to be powers of 2,
 831     * so we can take advantage of that for shift operations during
 832     * reads/writes */
 833    if (s->logical_sector_size & (s->logical_sector_size - 1)) {
 834        ret = -EINVAL;
 835        goto exit;
 836    }
 837    if (s->sectors_per_block & (s->sectors_per_block - 1)) {
 838        ret = -EINVAL;
 839        goto exit;
 840    }
 841    if (s->chunk_ratio & (s->chunk_ratio - 1)) {
 842        ret = -EINVAL;
 843        goto exit;
 844    }
 845    s->block_size = s->params.block_size;
 846    if (s->block_size & (s->block_size - 1)) {
 847        ret = -EINVAL;
 848        goto exit;
 849    }
 850
 851    vhdx_set_shift_bits(s);
 852
 853    ret = 0;
 854
 855exit:
 856    qemu_vfree(buffer);
 857    return ret;
 858}
 859
 860/*
 861 * Calculate the number of BAT entries, including sector
 862 * bitmap entries.
 863 */
 864static void vhdx_calc_bat_entries(BDRVVHDXState *s)
 865{
 866    uint32_t data_blocks_cnt, bitmap_blocks_cnt;
 867
 868    data_blocks_cnt = DIV_ROUND_UP(s->virtual_disk_size, s->block_size);
 869    bitmap_blocks_cnt = DIV_ROUND_UP(data_blocks_cnt, s->chunk_ratio);
 870
 871    if (s->parent_entries) {
 872        s->bat_entries = bitmap_blocks_cnt * (s->chunk_ratio + 1);
 873    } else {
 874        s->bat_entries = data_blocks_cnt +
 875                         ((data_blocks_cnt - 1) >> s->chunk_ratio_bits);
 876    }
 877
 878}
 879
 880static void vhdx_close(BlockDriverState *bs)
 881{
 882    BDRVVHDXState *s = bs->opaque;
 883    qemu_vfree(s->headers[0]);
 884    s->headers[0] = NULL;
 885    qemu_vfree(s->headers[1]);
 886    s->headers[1] = NULL;
 887    qemu_vfree(s->bat);
 888    s->bat = NULL;
 889    qemu_vfree(s->parent_entries);
 890    s->parent_entries = NULL;
 891    migrate_del_blocker(s->migration_blocker);
 892    error_free(s->migration_blocker);
 893    qemu_vfree(s->log.hdr);
 894    s->log.hdr = NULL;
 895    vhdx_region_unregister_all(s);
 896}
 897
 898static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
 899                     Error **errp)
 900{
 901    BDRVVHDXState *s = bs->opaque;
 902    int ret = 0;
 903    uint32_t i;
 904    uint64_t signature;
 905    Error *local_err = NULL;
 906
 907    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
 908                               false, errp);
 909    if (!bs->file) {
 910        return -EINVAL;
 911    }
 912
 913    s->bat = NULL;
 914    s->first_visible_write = true;
 915
 916    qemu_co_mutex_init(&s->lock);
 917    QLIST_INIT(&s->regions);
 918
 919    /* validate the file signature */
 920    ret = bdrv_pread(bs->file, 0, &signature, sizeof(uint64_t));
 921    if (ret < 0) {
 922        goto fail;
 923    }
 924    if (memcmp(&signature, "vhdxfile", 8)) {
 925        ret = -EINVAL;
 926        goto fail;
 927    }
 928
 929    /* This is used for any header updates, for the file_write_guid.
 930     * The spec dictates that a new value should be used for the first
 931     * header update */
 932    vhdx_guid_generate(&s->session_guid);
 933
 934    vhdx_parse_header(bs, s, &local_err);
 935    if (local_err != NULL) {
 936        error_propagate(errp, local_err);
 937        ret = -EINVAL;
 938        goto fail;
 939    }
 940
 941    ret = vhdx_parse_log(bs, s, &s->log_replayed_on_open, errp);
 942    if (ret < 0) {
 943        goto fail;
 944    }
 945
 946    ret = vhdx_open_region_tables(bs, s);
 947    if (ret < 0) {
 948        goto fail;
 949    }
 950
 951    ret = vhdx_parse_metadata(bs, s);
 952    if (ret < 0) {
 953        goto fail;
 954    }
 955
 956    s->block_size = s->params.block_size;
 957
 958    /* the VHDX spec dictates that virtual_disk_size is always a multiple of
 959     * logical_sector_size */
 960    bs->total_sectors = s->virtual_disk_size >> s->logical_sector_size_bits;
 961
 962    vhdx_calc_bat_entries(s);
 963
 964    s->bat_offset = s->bat_rt.file_offset;
 965
 966    if (s->bat_entries > s->bat_rt.length / sizeof(VHDXBatEntry)) {
 967        /* BAT allocation is not large enough for all entries */
 968        ret = -EINVAL;
 969        goto fail;
 970    }
 971
 972    /* s->bat is freed in vhdx_close() */
 973    s->bat = qemu_try_blockalign(bs->file->bs, s->bat_rt.length);
 974    if (s->bat == NULL) {
 975        ret = -ENOMEM;
 976        goto fail;
 977    }
 978
 979    ret = bdrv_pread(bs->file, s->bat_offset, s->bat, s->bat_rt.length);
 980    if (ret < 0) {
 981        goto fail;
 982    }
 983
 984    uint64_t payblocks = s->chunk_ratio;
 985    /* endian convert, and verify populated BAT field file offsets against
 986     * region table and log entries */
 987    for (i = 0; i < s->bat_entries; i++) {
 988        s->bat[i] = le64_to_cpu(s->bat[i]);
 989        if (payblocks--) {
 990            /* payload bat entries */
 991            if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) ==
 992                    PAYLOAD_BLOCK_FULLY_PRESENT) {
 993                ret = vhdx_region_check(s, s->bat[i] & VHDX_BAT_FILE_OFF_MASK,
 994                                        s->block_size);
 995                if (ret < 0) {
 996                    goto fail;
 997                }
 998            }
 999        } else {
1000            payblocks = s->chunk_ratio;
1001            /* Once differencing files are supported, verify sector bitmap
1002             * blocks here */
1003        }
1004    }
1005
1006    /* Disable migration when VHDX images are used */
1007    error_setg(&s->migration_blocker, "The vhdx format used by node '%s' "
1008               "does not support live migration",
1009               bdrv_get_device_or_node_name(bs));
1010    ret = migrate_add_blocker(s->migration_blocker, &local_err);
1011    if (local_err) {
1012        error_propagate(errp, local_err);
1013        error_free(s->migration_blocker);
1014        goto fail;
1015    }
1016
1017    /* TODO: differencing files */
1018
1019    return 0;
1020fail:
1021    vhdx_close(bs);
1022    return ret;
1023}
1024
1025static int vhdx_reopen_prepare(BDRVReopenState *state,
1026                               BlockReopenQueue *queue, Error **errp)
1027{
1028    return 0;
1029}
1030
1031
1032/*
1033 * Perform sector to block offset translations, to get various
1034 * sector and file offsets into the image.  See VHDXSectorInfo
1035 */
1036static void vhdx_block_translate(BDRVVHDXState *s, int64_t sector_num,
1037                                 int nb_sectors, VHDXSectorInfo *sinfo)
1038{
1039    uint32_t block_offset;
1040
1041    sinfo->bat_idx = sector_num >> s->sectors_per_block_bits;
1042    /* effectively a modulo - this gives us the offset into the block
1043     * (in sector sizes) for our sector number */
1044    block_offset = sector_num - (sinfo->bat_idx << s->sectors_per_block_bits);
1045    /* the chunk ratio gives us the interleaving of the sector
1046     * bitmaps, so we need to advance our page block index by the
1047     * sector bitmaps entry number */
1048    sinfo->bat_idx += sinfo->bat_idx >> s->chunk_ratio_bits;
1049
1050    /* the number of sectors we can read/write in this cycle */
1051    sinfo->sectors_avail = s->sectors_per_block - block_offset;
1052
1053    sinfo->bytes_left = sinfo->sectors_avail << s->logical_sector_size_bits;
1054
1055    if (sinfo->sectors_avail > nb_sectors) {
1056        sinfo->sectors_avail = nb_sectors;
1057    }
1058
1059    sinfo->bytes_avail = sinfo->sectors_avail << s->logical_sector_size_bits;
1060
1061    sinfo->file_offset = s->bat[sinfo->bat_idx] & VHDX_BAT_FILE_OFF_MASK;
1062
1063    sinfo->block_offset = block_offset << s->logical_sector_size_bits;
1064
1065    /* The file offset must be past the header section, so must be > 0 */
1066    if (sinfo->file_offset == 0) {
1067        return;
1068    }
1069
1070    /* block offset is the offset in vhdx logical sectors, in
1071     * the payload data block. Convert that to a byte offset
1072     * in the block, and add in the payload data block offset
1073     * in the file, in bytes, to get the final read address */
1074
1075    sinfo->file_offset += sinfo->block_offset;
1076}
1077
1078
1079static int vhdx_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1080{
1081    BDRVVHDXState *s = bs->opaque;
1082
1083    bdi->cluster_size = s->block_size;
1084
1085    bdi->unallocated_blocks_are_zero =
1086        (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) == 0;
1087
1088    return 0;
1089}
1090
1091
1092static coroutine_fn int vhdx_co_readv(BlockDriverState *bs, int64_t sector_num,
1093                                      int nb_sectors, QEMUIOVector *qiov)
1094{
1095    BDRVVHDXState *s = bs->opaque;
1096    int ret = 0;
1097    VHDXSectorInfo sinfo;
1098    uint64_t bytes_done = 0;
1099    QEMUIOVector hd_qiov;
1100
1101    qemu_iovec_init(&hd_qiov, qiov->niov);
1102
1103    qemu_co_mutex_lock(&s->lock);
1104
1105    while (nb_sectors > 0) {
1106        /* We are a differencing file, so we need to inspect the sector bitmap
1107         * to see if we have the data or not */
1108        if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1109            /* not supported yet */
1110            ret = -ENOTSUP;
1111            goto exit;
1112        } else {
1113            vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1114
1115            qemu_iovec_reset(&hd_qiov);
1116            qemu_iovec_concat(&hd_qiov, qiov,  bytes_done, sinfo.bytes_avail);
1117
1118            /* check the payload block state */
1119            switch (s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK) {
1120            case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1121            case PAYLOAD_BLOCK_UNDEFINED:
1122            case PAYLOAD_BLOCK_UNMAPPED:
1123            case PAYLOAD_BLOCK_UNMAPPED_v095:
1124            case PAYLOAD_BLOCK_ZERO:
1125                /* return zero */
1126                qemu_iovec_memset(&hd_qiov, 0, 0, sinfo.bytes_avail);
1127                break;
1128            case PAYLOAD_BLOCK_FULLY_PRESENT:
1129                qemu_co_mutex_unlock(&s->lock);
1130                ret = bdrv_co_preadv(bs->file, sinfo.file_offset,
1131                                     sinfo.sectors_avail * BDRV_SECTOR_SIZE,
1132                                     &hd_qiov, 0);
1133                qemu_co_mutex_lock(&s->lock);
1134                if (ret < 0) {
1135                    goto exit;
1136                }
1137                break;
1138            case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1139                /* we don't yet support difference files, fall through
1140                 * to error */
1141            default:
1142                ret = -EIO;
1143                goto exit;
1144                break;
1145            }
1146            nb_sectors -= sinfo.sectors_avail;
1147            sector_num += sinfo.sectors_avail;
1148            bytes_done += sinfo.bytes_avail;
1149        }
1150    }
1151    ret = 0;
1152exit:
1153    qemu_co_mutex_unlock(&s->lock);
1154    qemu_iovec_destroy(&hd_qiov);
1155    return ret;
1156}
1157
1158/*
1159 * Allocate a new payload block at the end of the file.
1160 *
1161 * Allocation will happen at 1MB alignment inside the file
1162 *
1163 * Returns the file offset start of the new payload block
1164 */
1165static int vhdx_allocate_block(BlockDriverState *bs, BDRVVHDXState *s,
1166                                    uint64_t *new_offset)
1167{
1168    int64_t current_len;
1169
1170    current_len = bdrv_getlength(bs->file->bs);
1171    if (current_len < 0) {
1172        return current_len;
1173    }
1174
1175    *new_offset = current_len;
1176
1177    /* per the spec, the address for a block is in units of 1MB */
1178    *new_offset = ROUND_UP(*new_offset, 1024 * 1024);
1179    if (*new_offset > INT64_MAX) {
1180        return -EINVAL;
1181    }
1182
1183    return bdrv_truncate(bs->file, *new_offset + s->block_size,
1184                         PREALLOC_MODE_OFF, NULL);
1185}
1186
1187/*
1188 * Update the BAT table entry with the new file offset, and the new entry
1189 * state */
1190static void vhdx_update_bat_table_entry(BlockDriverState *bs, BDRVVHDXState *s,
1191                                       VHDXSectorInfo *sinfo,
1192                                       uint64_t *bat_entry_le,
1193                                       uint64_t *bat_offset, int state)
1194{
1195    /* The BAT entry is a uint64, with 44 bits for the file offset in units of
1196     * 1MB, and 3 bits for the block state. */
1197    if ((state == PAYLOAD_BLOCK_ZERO)        ||
1198        (state == PAYLOAD_BLOCK_UNDEFINED)   ||
1199        (state == PAYLOAD_BLOCK_NOT_PRESENT) ||
1200        (state == PAYLOAD_BLOCK_UNMAPPED)) {
1201        s->bat[sinfo->bat_idx]  = 0;  /* For PAYLOAD_BLOCK_ZERO, the
1202                                         FileOffsetMB field is denoted as
1203                                         'reserved' in the v1.0 spec.  If it is
1204                                         non-zero, MS Hyper-V will fail to read
1205                                         the disk image */
1206    } else {
1207        s->bat[sinfo->bat_idx]  = sinfo->file_offset;
1208    }
1209
1210    s->bat[sinfo->bat_idx] |= state & VHDX_BAT_STATE_BIT_MASK;
1211
1212    *bat_entry_le = cpu_to_le64(s->bat[sinfo->bat_idx]);
1213    *bat_offset = s->bat_offset + sinfo->bat_idx * sizeof(VHDXBatEntry);
1214
1215}
1216
1217/* Per the spec, on the first write of guest-visible data to the file the
1218 * data write guid must be updated in the header */
1219int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s)
1220{
1221    int ret = 0;
1222    if (s->first_visible_write) {
1223        s->first_visible_write = false;
1224        ret = vhdx_update_headers(bs, s, true, NULL);
1225    }
1226    return ret;
1227}
1228
1229static coroutine_fn int vhdx_co_writev(BlockDriverState *bs, int64_t sector_num,
1230                                       int nb_sectors, QEMUIOVector *qiov,
1231                                       int flags)
1232{
1233    int ret = -ENOTSUP;
1234    BDRVVHDXState *s = bs->opaque;
1235    VHDXSectorInfo sinfo;
1236    uint64_t bytes_done = 0;
1237    uint64_t bat_entry = 0;
1238    uint64_t bat_entry_offset = 0;
1239    QEMUIOVector hd_qiov;
1240    struct iovec iov1 = { 0 };
1241    struct iovec iov2 = { 0 };
1242    int sectors_to_write;
1243    int bat_state;
1244    uint64_t bat_prior_offset = 0;
1245    bool bat_update = false;
1246
1247    assert(!flags);
1248    qemu_iovec_init(&hd_qiov, qiov->niov);
1249
1250    qemu_co_mutex_lock(&s->lock);
1251
1252    ret = vhdx_user_visible_write(bs, s);
1253    if (ret < 0) {
1254        goto exit;
1255    }
1256
1257    while (nb_sectors > 0) {
1258        bool use_zero_buffers = false;
1259        bat_update = false;
1260        if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1261            /* not supported yet */
1262            ret = -ENOTSUP;
1263            goto exit;
1264        } else {
1265            vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1266            sectors_to_write = sinfo.sectors_avail;
1267
1268            qemu_iovec_reset(&hd_qiov);
1269            /* check the payload block state */
1270            bat_state = s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK;
1271            switch (bat_state) {
1272            case PAYLOAD_BLOCK_ZERO:
1273                /* in this case, we need to preserve zero writes for
1274                 * data that is not part of this write, so we must pad
1275                 * the rest of the buffer to zeroes */
1276
1277                /* if we are on a posix system with ftruncate() that extends
1278                 * a file, then it is zero-filled for us.  On Win32, the raw
1279                 * layer uses SetFilePointer and SetFileEnd, which does not
1280                 * zero fill AFAIK */
1281
1282                /* Queue another write of zero buffers if the underlying file
1283                 * does not zero-fill on file extension */
1284
1285                if (bdrv_has_zero_init(bs->file->bs) == 0) {
1286                    use_zero_buffers = true;
1287
1288                    /* zero fill the front, if any */
1289                    if (sinfo.block_offset) {
1290                        iov1.iov_len = sinfo.block_offset;
1291                        iov1.iov_base = qemu_blockalign(bs, iov1.iov_len);
1292                        memset(iov1.iov_base, 0, iov1.iov_len);
1293                        qemu_iovec_concat_iov(&hd_qiov, &iov1, 1, 0,
1294                                              iov1.iov_len);
1295                        sectors_to_write += iov1.iov_len >> BDRV_SECTOR_BITS;
1296                    }
1297
1298                    /* our actual data */
1299                    qemu_iovec_concat(&hd_qiov, qiov,  bytes_done,
1300                                      sinfo.bytes_avail);
1301
1302                    /* zero fill the back, if any */
1303                    if ((sinfo.bytes_avail - sinfo.block_offset) <
1304                         s->block_size) {
1305                        iov2.iov_len = s->block_size -
1306                                      (sinfo.bytes_avail + sinfo.block_offset);
1307                        iov2.iov_base = qemu_blockalign(bs, iov2.iov_len);
1308                        memset(iov2.iov_base, 0, iov2.iov_len);
1309                        qemu_iovec_concat_iov(&hd_qiov, &iov2, 1, 0,
1310                                              iov2.iov_len);
1311                        sectors_to_write += iov2.iov_len >> BDRV_SECTOR_BITS;
1312                    }
1313                }
1314                /* fall through */
1315            case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1316            case PAYLOAD_BLOCK_UNMAPPED:
1317            case PAYLOAD_BLOCK_UNMAPPED_v095:
1318            case PAYLOAD_BLOCK_UNDEFINED:
1319                bat_prior_offset = sinfo.file_offset;
1320                ret = vhdx_allocate_block(bs, s, &sinfo.file_offset);
1321                if (ret < 0) {
1322                    goto exit;
1323                }
1324                /* once we support differencing files, this may also be
1325                 * partially present */
1326                /* update block state to the newly specified state */
1327                vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1328                                            &bat_entry_offset,
1329                                            PAYLOAD_BLOCK_FULLY_PRESENT);
1330                bat_update = true;
1331                /* since we just allocated a block, file_offset is the
1332                 * beginning of the payload block. It needs to be the
1333                 * write address, which includes the offset into the block */
1334                if (!use_zero_buffers) {
1335                    sinfo.file_offset += sinfo.block_offset;
1336                }
1337                /* fall through */
1338            case PAYLOAD_BLOCK_FULLY_PRESENT:
1339                /* if the file offset address is in the header zone,
1340                 * there is a problem */
1341                if (sinfo.file_offset < (1024 * 1024)) {
1342                    ret = -EFAULT;
1343                    goto error_bat_restore;
1344                }
1345
1346                if (!use_zero_buffers) {
1347                    qemu_iovec_concat(&hd_qiov, qiov,  bytes_done,
1348                                      sinfo.bytes_avail);
1349                }
1350                /* block exists, so we can just overwrite it */
1351                qemu_co_mutex_unlock(&s->lock);
1352                ret = bdrv_co_pwritev(bs->file, sinfo.file_offset,
1353                                      sectors_to_write * BDRV_SECTOR_SIZE,
1354                                      &hd_qiov, 0);
1355                qemu_co_mutex_lock(&s->lock);
1356                if (ret < 0) {
1357                    goto error_bat_restore;
1358                }
1359                break;
1360            case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1361                /* we don't yet support difference files, fall through
1362                 * to error */
1363            default:
1364                ret = -EIO;
1365                goto exit;
1366                break;
1367            }
1368
1369            if (bat_update) {
1370                /* this will update the BAT entry into the log journal, and
1371                 * then flush the log journal out to disk */
1372                ret =  vhdx_log_write_and_flush(bs, s, &bat_entry,
1373                                                sizeof(VHDXBatEntry),
1374                                                bat_entry_offset);
1375                if (ret < 0) {
1376                    goto exit;
1377                }
1378            }
1379
1380            nb_sectors -= sinfo.sectors_avail;
1381            sector_num += sinfo.sectors_avail;
1382            bytes_done += sinfo.bytes_avail;
1383
1384        }
1385    }
1386
1387    goto exit;
1388
1389error_bat_restore:
1390    if (bat_update) {
1391        /* keep metadata in sync, and restore the bat entry state
1392         * if error. */
1393        sinfo.file_offset = bat_prior_offset;
1394        vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1395                                    &bat_entry_offset, bat_state);
1396    }
1397exit:
1398    qemu_vfree(iov1.iov_base);
1399    qemu_vfree(iov2.iov_base);
1400    qemu_co_mutex_unlock(&s->lock);
1401    qemu_iovec_destroy(&hd_qiov);
1402    return ret;
1403}
1404
1405
1406
1407/*
1408 * Create VHDX Headers
1409 *
1410 * There are 2 headers, and the highest sequence number will represent
1411 * the active header
1412 */
1413static int vhdx_create_new_headers(BlockBackend *blk, uint64_t image_size,
1414                                   uint32_t log_size)
1415{
1416    BlockDriverState *bs = blk_bs(blk);
1417    BdrvChild *child;
1418    int ret = 0;
1419    VHDXHeader *hdr = NULL;
1420
1421    hdr = g_new0(VHDXHeader, 1);
1422
1423    hdr->signature       = VHDX_HEADER_SIGNATURE;
1424    hdr->sequence_number = g_random_int();
1425    hdr->log_version     = 0;
1426    hdr->version         = 1;
1427    hdr->log_length      = log_size;
1428    hdr->log_offset      = VHDX_HEADER_SECTION_END;
1429    vhdx_guid_generate(&hdr->file_write_guid);
1430    vhdx_guid_generate(&hdr->data_write_guid);
1431
1432    /* XXX Ugly way to get blk->root, but that's a feature, not a bug. This
1433     * hack makes it obvious that vhdx_write_header() bypasses the BlockBackend
1434     * here, which it really shouldn't be doing. */
1435    child = QLIST_FIRST(&bs->parents);
1436    assert(!QLIST_NEXT(child, next_parent));
1437
1438    ret = vhdx_write_header(child, hdr, VHDX_HEADER1_OFFSET, false);
1439    if (ret < 0) {
1440        goto exit;
1441    }
1442    hdr->sequence_number++;
1443    ret = vhdx_write_header(child, hdr, VHDX_HEADER2_OFFSET, false);
1444    if (ret < 0) {
1445        goto exit;
1446    }
1447
1448exit:
1449    g_free(hdr);
1450    return ret;
1451}
1452
1453#define VHDX_METADATA_ENTRY_BUFFER_SIZE \
1454                                    (sizeof(VHDXFileParameters)               +\
1455                                     sizeof(VHDXVirtualDiskSize)              +\
1456                                     sizeof(VHDXPage83Data)                   +\
1457                                     sizeof(VHDXVirtualDiskLogicalSectorSize) +\
1458                                     sizeof(VHDXVirtualDiskPhysicalSectorSize))
1459
1460/*
1461 * Create the Metadata entries.
1462 *
1463 * For more details on the entries, see section 3.5 (pg 29) in the
1464 * VHDX 1.00 specification.
1465 *
1466 * We support 5 metadata entries (all required by spec):
1467 *          File Parameters,
1468 *          Virtual Disk Size,
1469 *          Page 83 Data,
1470 *          Logical Sector Size,
1471 *          Physical Sector Size
1472 *
1473 * The first 64KB of the Metadata section is reserved for the metadata
1474 * header and entries; beyond that, the metadata items themselves reside.
1475 */
1476static int vhdx_create_new_metadata(BlockBackend *blk,
1477                                    uint64_t image_size,
1478                                    uint32_t block_size,
1479                                    uint32_t sector_size,
1480                                    uint64_t metadata_offset,
1481                                    VHDXImageType type)
1482{
1483    int ret = 0;
1484    uint32_t offset = 0;
1485    void *buffer = NULL;
1486    void *entry_buffer;
1487    VHDXMetadataTableHeader *md_table;
1488    VHDXMetadataTableEntry  *md_table_entry;
1489
1490    /* Metadata entries */
1491    VHDXFileParameters     *mt_file_params;
1492    VHDXVirtualDiskSize    *mt_virtual_size;
1493    VHDXPage83Data         *mt_page83;
1494    VHDXVirtualDiskLogicalSectorSize  *mt_log_sector_size;
1495    VHDXVirtualDiskPhysicalSectorSize *mt_phys_sector_size;
1496
1497    entry_buffer = g_malloc0(VHDX_METADATA_ENTRY_BUFFER_SIZE);
1498
1499    mt_file_params = entry_buffer;
1500    offset += sizeof(VHDXFileParameters);
1501    mt_virtual_size = entry_buffer + offset;
1502    offset += sizeof(VHDXVirtualDiskSize);
1503    mt_page83 = entry_buffer + offset;
1504    offset += sizeof(VHDXPage83Data);
1505    mt_log_sector_size = entry_buffer + offset;
1506    offset += sizeof(VHDXVirtualDiskLogicalSectorSize);
1507    mt_phys_sector_size = entry_buffer + offset;
1508
1509    mt_file_params->block_size = cpu_to_le32(block_size);
1510    if (type == VHDX_TYPE_FIXED) {
1511        mt_file_params->data_bits |= VHDX_PARAMS_LEAVE_BLOCKS_ALLOCED;
1512        mt_file_params->data_bits = cpu_to_le32(mt_file_params->data_bits);
1513    }
1514
1515    vhdx_guid_generate(&mt_page83->page_83_data);
1516    cpu_to_leguids(&mt_page83->page_83_data);
1517    mt_virtual_size->virtual_disk_size        = cpu_to_le64(image_size);
1518    mt_log_sector_size->logical_sector_size   = cpu_to_le32(sector_size);
1519    mt_phys_sector_size->physical_sector_size = cpu_to_le32(sector_size);
1520
1521    buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1522    md_table = buffer;
1523
1524    md_table->signature   = VHDX_METADATA_SIGNATURE;
1525    md_table->entry_count = 5;
1526    vhdx_metadata_header_le_export(md_table);
1527
1528
1529    /* This will reference beyond the reserved table portion */
1530    offset = 64 * KiB;
1531
1532    md_table_entry = buffer + sizeof(VHDXMetadataTableHeader);
1533
1534    md_table_entry[0].item_id = file_param_guid;
1535    md_table_entry[0].offset  = offset;
1536    md_table_entry[0].length  = sizeof(VHDXFileParameters);
1537    md_table_entry[0].data_bits |= VHDX_META_FLAGS_IS_REQUIRED;
1538    offset += md_table_entry[0].length;
1539    vhdx_metadata_entry_le_export(&md_table_entry[0]);
1540
1541    md_table_entry[1].item_id = virtual_size_guid;
1542    md_table_entry[1].offset  = offset;
1543    md_table_entry[1].length  = sizeof(VHDXVirtualDiskSize);
1544    md_table_entry[1].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1545                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1546    offset += md_table_entry[1].length;
1547    vhdx_metadata_entry_le_export(&md_table_entry[1]);
1548
1549    md_table_entry[2].item_id = page83_guid;
1550    md_table_entry[2].offset  = offset;
1551    md_table_entry[2].length  = sizeof(VHDXPage83Data);
1552    md_table_entry[2].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1553                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1554    offset += md_table_entry[2].length;
1555    vhdx_metadata_entry_le_export(&md_table_entry[2]);
1556
1557    md_table_entry[3].item_id = logical_sector_guid;
1558    md_table_entry[3].offset  = offset;
1559    md_table_entry[3].length  = sizeof(VHDXVirtualDiskLogicalSectorSize);
1560    md_table_entry[3].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1561                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1562    offset += md_table_entry[3].length;
1563    vhdx_metadata_entry_le_export(&md_table_entry[3]);
1564
1565    md_table_entry[4].item_id = phys_sector_guid;
1566    md_table_entry[4].offset  = offset;
1567    md_table_entry[4].length  = sizeof(VHDXVirtualDiskPhysicalSectorSize);
1568    md_table_entry[4].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1569                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1570    vhdx_metadata_entry_le_export(&md_table_entry[4]);
1571
1572    ret = blk_pwrite(blk, metadata_offset, buffer, VHDX_HEADER_BLOCK_SIZE, 0);
1573    if (ret < 0) {
1574        goto exit;
1575    }
1576
1577    ret = blk_pwrite(blk, metadata_offset + (64 * KiB), entry_buffer,
1578                     VHDX_METADATA_ENTRY_BUFFER_SIZE, 0);
1579    if (ret < 0) {
1580        goto exit;
1581    }
1582
1583
1584exit:
1585    g_free(buffer);
1586    g_free(entry_buffer);
1587    return ret;
1588}
1589
1590/* This create the actual BAT itself.  We currently only support
1591 * 'Dynamic' and 'Fixed' image types.
1592 *
1593 *  Dynamic images: default state of the BAT is all zeroes.
1594 *
1595 *  Fixed images: default state of the BAT is fully populated, with
1596 *                file offsets and state PAYLOAD_BLOCK_FULLY_PRESENT.
1597 */
1598static int vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
1599                           uint64_t image_size, VHDXImageType type,
1600                           bool use_zero_blocks, uint64_t file_offset,
1601                           uint32_t length, Error **errp)
1602{
1603    int ret = 0;
1604    uint64_t data_file_offset;
1605    uint64_t total_sectors = 0;
1606    uint64_t sector_num = 0;
1607    uint64_t unused;
1608    int block_state;
1609    VHDXSectorInfo sinfo;
1610
1611    assert(s->bat == NULL);
1612
1613    /* this gives a data start after BAT/bitmap entries, and well
1614     * past any metadata entries (with a 4 MB buffer for future
1615     * expansion */
1616    data_file_offset = file_offset + length + 5 * MiB;
1617    total_sectors = image_size >> s->logical_sector_size_bits;
1618
1619    if (type == VHDX_TYPE_DYNAMIC) {
1620        /* All zeroes, so we can just extend the file - the end of the BAT
1621         * is the furthest thing we have written yet */
1622        ret = blk_truncate(blk, data_file_offset, PREALLOC_MODE_OFF, errp);
1623        if (ret < 0) {
1624            goto exit;
1625        }
1626    } else if (type == VHDX_TYPE_FIXED) {
1627        ret = blk_truncate(blk, data_file_offset + image_size,
1628                           PREALLOC_MODE_OFF, errp);
1629        if (ret < 0) {
1630            goto exit;
1631        }
1632    } else {
1633        error_setg(errp, "Unsupported image type");
1634        ret = -ENOTSUP;
1635        goto exit;
1636    }
1637
1638    if (type == VHDX_TYPE_FIXED ||
1639                use_zero_blocks ||
1640                bdrv_has_zero_init(blk_bs(blk)) == 0) {
1641        /* for a fixed file, the default BAT entry is not zero */
1642        s->bat = g_try_malloc0(length);
1643        if (length && s->bat == NULL) {
1644            error_setg(errp, "Failed to allocate memory for the BAT");
1645            ret = -ENOMEM;
1646            goto exit;
1647        }
1648        block_state = type == VHDX_TYPE_FIXED ? PAYLOAD_BLOCK_FULLY_PRESENT :
1649                                                PAYLOAD_BLOCK_NOT_PRESENT;
1650        block_state = use_zero_blocks ? PAYLOAD_BLOCK_ZERO : block_state;
1651        /* fill the BAT by emulating sector writes of sectors_per_block size */
1652        while (sector_num < total_sectors) {
1653            vhdx_block_translate(s, sector_num, s->sectors_per_block, &sinfo);
1654            sinfo.file_offset = data_file_offset +
1655                                (sector_num << s->logical_sector_size_bits);
1656            sinfo.file_offset = ROUND_UP(sinfo.file_offset, MiB);
1657            vhdx_update_bat_table_entry(blk_bs(blk), s, &sinfo, &unused, &unused,
1658                                        block_state);
1659            s->bat[sinfo.bat_idx] = cpu_to_le64(s->bat[sinfo.bat_idx]);
1660            sector_num += s->sectors_per_block;
1661        }
1662        ret = blk_pwrite(blk, file_offset, s->bat, length, 0);
1663        if (ret < 0) {
1664            error_setg_errno(errp, -ret, "Failed to write the BAT");
1665            goto exit;
1666        }
1667    }
1668
1669
1670
1671exit:
1672    g_free(s->bat);
1673    return ret;
1674}
1675
1676/* Creates the region table header, and region table entries.
1677 * There are 2 supported region table entries: BAT, and Metadata/
1678 *
1679 * As the calculations for the BAT region table are also needed
1680 * to create the BAT itself, we will also cause the BAT to be
1681 * created.
1682 */
1683static int vhdx_create_new_region_table(BlockBackend *blk,
1684                                        uint64_t image_size,
1685                                        uint32_t block_size,
1686                                        uint32_t sector_size,
1687                                        uint32_t log_size,
1688                                        bool use_zero_blocks,
1689                                        VHDXImageType type,
1690                                        uint64_t *metadata_offset,
1691                                        Error **errp)
1692{
1693    int ret = 0;
1694    uint32_t offset = 0;
1695    void *buffer = NULL;
1696    uint64_t bat_file_offset;
1697    uint32_t bat_length;
1698    BDRVVHDXState *s = NULL;
1699    VHDXRegionTableHeader *region_table;
1700    VHDXRegionTableEntry *rt_bat;
1701    VHDXRegionTableEntry *rt_metadata;
1702
1703    assert(metadata_offset != NULL);
1704
1705    /* Populate enough of the BDRVVHDXState to be able to use the
1706     * pre-existing BAT calculation, translation, and update functions */
1707    s = g_new0(BDRVVHDXState, 1);
1708
1709    s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
1710                     (uint64_t) sector_size / (uint64_t) block_size;
1711
1712    s->sectors_per_block = block_size / sector_size;
1713    s->virtual_disk_size = image_size;
1714    s->block_size = block_size;
1715    s->logical_sector_size = sector_size;
1716
1717    vhdx_set_shift_bits(s);
1718
1719    vhdx_calc_bat_entries(s);
1720
1721    /* At this point the VHDX state is populated enough for creation */
1722
1723    /* a single buffer is used so we can calculate the checksum over the
1724     * entire 64KB block */
1725    buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1726    region_table = buffer;
1727    offset += sizeof(VHDXRegionTableHeader);
1728    rt_bat = buffer + offset;
1729    offset += sizeof(VHDXRegionTableEntry);
1730    rt_metadata  = buffer + offset;
1731
1732    region_table->signature = VHDX_REGION_SIGNATURE;
1733    region_table->entry_count = 2;   /* BAT and Metadata */
1734
1735    rt_bat->guid        = bat_guid;
1736    rt_bat->length      = ROUND_UP(s->bat_entries * sizeof(VHDXBatEntry), MiB);
1737    rt_bat->file_offset = ROUND_UP(VHDX_HEADER_SECTION_END + log_size, MiB);
1738    s->bat_offset = rt_bat->file_offset;
1739
1740    rt_metadata->guid        = metadata_guid;
1741    rt_metadata->file_offset = ROUND_UP(rt_bat->file_offset + rt_bat->length,
1742                                        MiB);
1743    rt_metadata->length      = 1 * MiB; /* min size, and more than enough */
1744    *metadata_offset = rt_metadata->file_offset;
1745
1746    bat_file_offset = rt_bat->file_offset;
1747    bat_length = rt_bat->length;
1748
1749    vhdx_region_header_le_export(region_table);
1750    vhdx_region_entry_le_export(rt_bat);
1751    vhdx_region_entry_le_export(rt_metadata);
1752
1753    vhdx_update_checksum(buffer, VHDX_HEADER_BLOCK_SIZE,
1754                         offsetof(VHDXRegionTableHeader, checksum));
1755
1756
1757    /* The region table gives us the data we need to create the BAT,
1758     * so do that now */
1759    ret = vhdx_create_bat(blk, s, image_size, type, use_zero_blocks,
1760                          bat_file_offset, bat_length, errp);
1761    if (ret < 0) {
1762        goto exit;
1763    }
1764
1765    /* Now write out the region headers to disk */
1766    ret = blk_pwrite(blk, VHDX_REGION_TABLE_OFFSET, buffer,
1767                     VHDX_HEADER_BLOCK_SIZE, 0);
1768    if (ret < 0) {
1769        error_setg_errno(errp, -ret, "Failed to write first region table");
1770        goto exit;
1771    }
1772
1773    ret = blk_pwrite(blk, VHDX_REGION_TABLE2_OFFSET, buffer,
1774                     VHDX_HEADER_BLOCK_SIZE, 0);
1775    if (ret < 0) {
1776        error_setg_errno(errp, -ret, "Failed to write second region table");
1777        goto exit;
1778    }
1779
1780exit:
1781    g_free(s);
1782    g_free(buffer);
1783    return ret;
1784}
1785
1786/* We need to create the following elements:
1787 *
1788 *    .-----------------------------------------------------------------.
1789 *    |   (A)    |   (B)    |    (C)    |     (D)       |     (E)       |
1790 *    |  File ID |  Header1 |  Header 2 |  Region Tbl 1 |  Region Tbl 2 |
1791 *    |          |          |           |               |               |
1792 *    .-----------------------------------------------------------------.
1793 *    0         64KB      128KB       192KB           256KB           320KB
1794 *
1795 *
1796 *    .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1797 *    |     (F)     |     (G)       |    (H)    |                        |
1798 *    | Journal Log |  BAT / Bitmap |  Metadata |  .... data ......      |
1799 *    |             |               |           |                        |
1800 *    .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1801 *   1MB
1802 */
1803static int coroutine_fn vhdx_co_create(BlockdevCreateOptions *opts,
1804                                       Error **errp)
1805{
1806    BlockdevCreateOptionsVhdx *vhdx_opts;
1807    BlockBackend *blk = NULL;
1808    BlockDriverState *bs = NULL;
1809
1810    int ret = 0;
1811    uint64_t image_size;
1812    uint32_t log_size;
1813    uint32_t block_size;
1814    uint64_t signature;
1815    uint64_t metadata_offset;
1816    bool use_zero_blocks = false;
1817
1818    gunichar2 *creator = NULL;
1819    glong creator_items;
1820    VHDXImageType image_type;
1821
1822    assert(opts->driver == BLOCKDEV_DRIVER_VHDX);
1823    vhdx_opts = &opts->u.vhdx;
1824
1825    /* Validate options and set default values */
1826    image_size = vhdx_opts->size;
1827    if (image_size > VHDX_MAX_IMAGE_SIZE) {
1828        error_setg(errp, "Image size too large; max of 64TB");
1829        return -EINVAL;
1830    }
1831
1832    if (!vhdx_opts->has_log_size) {
1833        log_size = DEFAULT_LOG_SIZE;
1834    } else {
1835        if (vhdx_opts->log_size > UINT32_MAX) {
1836            error_setg(errp, "Log size must be smaller than 4 GB");
1837            return -EINVAL;
1838        }
1839        log_size = vhdx_opts->log_size;
1840    }
1841    if (log_size < MiB || (log_size % MiB) != 0) {
1842        error_setg(errp, "Log size must be a multiple of 1 MB");
1843        return -EINVAL;
1844    }
1845
1846    if (!vhdx_opts->has_block_state_zero) {
1847        use_zero_blocks = true;
1848    } else {
1849        use_zero_blocks = vhdx_opts->block_state_zero;
1850    }
1851
1852    if (!vhdx_opts->has_subformat) {
1853        vhdx_opts->subformat = BLOCKDEV_VHDX_SUBFORMAT_DYNAMIC;
1854    }
1855
1856    switch (vhdx_opts->subformat) {
1857    case BLOCKDEV_VHDX_SUBFORMAT_DYNAMIC:
1858        image_type = VHDX_TYPE_DYNAMIC;
1859        break;
1860    case BLOCKDEV_VHDX_SUBFORMAT_FIXED:
1861        image_type = VHDX_TYPE_FIXED;
1862        break;
1863    default:
1864        g_assert_not_reached();
1865    }
1866
1867    /* These are pretty arbitrary, and mainly designed to keep the BAT
1868     * size reasonable to load into RAM */
1869    if (vhdx_opts->has_block_size) {
1870        block_size = vhdx_opts->block_size;
1871    } else {
1872        if (image_size > 32 * TiB) {
1873            block_size = 64 * MiB;
1874        } else if (image_size > (uint64_t) 100 * GiB) {
1875            block_size = 32 * MiB;
1876        } else if (image_size > 1 * GiB) {
1877            block_size = 16 * MiB;
1878        } else {
1879            block_size = 8 * MiB;
1880        }
1881    }
1882
1883    if (block_size < MiB || (block_size % MiB) != 0) {
1884        error_setg(errp, "Block size must be a multiple of 1 MB");
1885        return -EINVAL;
1886    }
1887    if (!is_power_of_2(block_size)) {
1888        error_setg(errp, "Block size must be a power of two");
1889        return -EINVAL;
1890    }
1891    if (block_size > VHDX_BLOCK_SIZE_MAX) {
1892        error_setg(errp, "Block size must not exceed %d", VHDX_BLOCK_SIZE_MAX);
1893        return -EINVAL;
1894    }
1895
1896    /* Create BlockBackend to write to the image */
1897    bs = bdrv_open_blockdev_ref(vhdx_opts->file, errp);
1898    if (bs == NULL) {
1899        return -EIO;
1900    }
1901
1902    blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
1903    ret = blk_insert_bs(blk, bs, errp);
1904    if (ret < 0) {
1905        goto delete_and_exit;
1906    }
1907    blk_set_allow_write_beyond_eof(blk, true);
1908
1909    /* Create (A) */
1910
1911    /* The creator field is optional, but may be useful for
1912     * debugging / diagnostics */
1913    creator = g_utf8_to_utf16("QEMU v" QEMU_VERSION, -1, NULL,
1914                              &creator_items, NULL);
1915    signature = cpu_to_le64(VHDX_FILE_SIGNATURE);
1916    ret = blk_pwrite(blk, VHDX_FILE_ID_OFFSET, &signature, sizeof(signature),
1917                     0);
1918    if (ret < 0) {
1919        error_setg_errno(errp, -ret, "Failed to write file signature");
1920        goto delete_and_exit;
1921    }
1922    if (creator) {
1923        ret = blk_pwrite(blk, VHDX_FILE_ID_OFFSET + sizeof(signature),
1924                         creator, creator_items * sizeof(gunichar2), 0);
1925        if (ret < 0) {
1926            error_setg_errno(errp, -ret, "Failed to write creator field");
1927            goto delete_and_exit;
1928        }
1929    }
1930
1931
1932    /* Creates (B),(C) */
1933    ret = vhdx_create_new_headers(blk, image_size, log_size);
1934    if (ret < 0) {
1935        error_setg_errno(errp, -ret, "Failed to write image headers");
1936        goto delete_and_exit;
1937    }
1938
1939    /* Creates (D),(E),(G) explicitly. (F) created as by-product */
1940    ret = vhdx_create_new_region_table(blk, image_size, block_size, 512,
1941                                       log_size, use_zero_blocks, image_type,
1942                                       &metadata_offset, errp);
1943    if (ret < 0) {
1944        goto delete_and_exit;
1945    }
1946
1947    /* Creates (H) */
1948    ret = vhdx_create_new_metadata(blk, image_size, block_size, 512,
1949                                   metadata_offset, image_type);
1950    if (ret < 0) {
1951        error_setg_errno(errp, -ret, "Failed to initialize metadata");
1952        goto delete_and_exit;
1953    }
1954
1955    ret = 0;
1956delete_and_exit:
1957    blk_unref(blk);
1958    bdrv_unref(bs);
1959    g_free(creator);
1960    return ret;
1961}
1962
1963static int coroutine_fn vhdx_co_create_opts(const char *filename,
1964                                            QemuOpts *opts,
1965                                            Error **errp)
1966{
1967    BlockdevCreateOptions *create_options = NULL;
1968    QDict *qdict;
1969    Visitor *v;
1970    BlockDriverState *bs = NULL;
1971    Error *local_err = NULL;
1972    int ret;
1973
1974    static const QDictRenames opt_renames[] = {
1975        { VHDX_BLOCK_OPT_LOG_SIZE,      "log-size" },
1976        { VHDX_BLOCK_OPT_BLOCK_SIZE,    "block-size" },
1977        { VHDX_BLOCK_OPT_ZERO,          "block-state-zero" },
1978        { NULL, NULL },
1979    };
1980
1981    /* Parse options and convert legacy syntax */
1982    qdict = qemu_opts_to_qdict_filtered(opts, NULL, &vhdx_create_opts, true);
1983
1984    if (!qdict_rename_keys(qdict, opt_renames, errp)) {
1985        ret = -EINVAL;
1986        goto fail;
1987    }
1988
1989    /* Create and open the file (protocol layer) */
1990    ret = bdrv_create_file(filename, opts, &local_err);
1991    if (ret < 0) {
1992        error_propagate(errp, local_err);
1993        goto fail;
1994    }
1995
1996    bs = bdrv_open(filename, NULL, NULL,
1997                   BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
1998    if (bs == NULL) {
1999        ret = -EIO;
2000        goto fail;
2001    }
2002
2003    /* Now get the QAPI type BlockdevCreateOptions */
2004    qdict_put_str(qdict, "driver", "vhdx");
2005    qdict_put_str(qdict, "file", bs->node_name);
2006
2007    v = qobject_input_visitor_new_flat_confused(qdict, errp);
2008    if (!v) {
2009        ret = -EINVAL;
2010        goto fail;
2011    }
2012
2013    visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err);
2014    visit_free(v);
2015
2016    if (local_err) {
2017        error_propagate(errp, local_err);
2018        ret = -EINVAL;
2019        goto fail;
2020    }
2021
2022    /* Silently round up sizes:
2023     * The image size is rounded to 512 bytes. Make the block and log size
2024     * close to what was specified, but must be at least 1MB, and a multiple of
2025     * 1 MB. Also respect VHDX_BLOCK_SIZE_MAX for block sizes. block_size = 0
2026     * means auto, which is represented by a missing key in QAPI. */
2027    assert(create_options->driver == BLOCKDEV_DRIVER_VHDX);
2028    create_options->u.vhdx.size =
2029        ROUND_UP(create_options->u.vhdx.size, BDRV_SECTOR_SIZE);
2030
2031    if (create_options->u.vhdx.has_log_size) {
2032        create_options->u.vhdx.log_size =
2033            ROUND_UP(create_options->u.vhdx.log_size, MiB);
2034    }
2035    if (create_options->u.vhdx.has_block_size) {
2036        create_options->u.vhdx.block_size =
2037            ROUND_UP(create_options->u.vhdx.block_size, MiB);
2038
2039        if (create_options->u.vhdx.block_size == 0) {
2040            create_options->u.vhdx.has_block_size = false;
2041        }
2042        if (create_options->u.vhdx.block_size > VHDX_BLOCK_SIZE_MAX) {
2043            create_options->u.vhdx.block_size = VHDX_BLOCK_SIZE_MAX;
2044        }
2045    }
2046
2047    /* Create the vhdx image (format layer) */
2048    ret = vhdx_co_create(create_options, errp);
2049
2050fail:
2051    qobject_unref(qdict);
2052    bdrv_unref(bs);
2053    qapi_free_BlockdevCreateOptions(create_options);
2054    return ret;
2055}
2056
2057/* If opened r/w, the VHDX driver will automatically replay the log,
2058 * if one is present, inside the vhdx_open() call.
2059 *
2060 * If qemu-img check -r all is called, the image is automatically opened
2061 * r/w and any log has already been replayed, so there is nothing (currently)
2062 * for us to do here
2063 */
2064static int coroutine_fn vhdx_co_check(BlockDriverState *bs,
2065                                      BdrvCheckResult *result,
2066                                      BdrvCheckMode fix)
2067{
2068    BDRVVHDXState *s = bs->opaque;
2069
2070    if (s->log_replayed_on_open) {
2071        result->corruptions_fixed++;
2072    }
2073    return 0;
2074}
2075
2076static QemuOptsList vhdx_create_opts = {
2077    .name = "vhdx-create-opts",
2078    .head = QTAILQ_HEAD_INITIALIZER(vhdx_create_opts.head),
2079    .desc = {
2080        {
2081           .name = BLOCK_OPT_SIZE,
2082           .type = QEMU_OPT_SIZE,
2083           .help = "Virtual disk size; max of 64TB."
2084       },
2085       {
2086           .name = VHDX_BLOCK_OPT_LOG_SIZE,
2087           .type = QEMU_OPT_SIZE,
2088           .def_value_str = stringify(DEFAULT_LOG_SIZE),
2089           .help = "Log size; min 1MB."
2090       },
2091       {
2092           .name = VHDX_BLOCK_OPT_BLOCK_SIZE,
2093           .type = QEMU_OPT_SIZE,
2094           .def_value_str = stringify(0),
2095           .help = "Block Size; min 1MB, max 256MB. " \
2096                   "0 means auto-calculate based on image size."
2097       },
2098       {
2099           .name = BLOCK_OPT_SUBFMT,
2100           .type = QEMU_OPT_STRING,
2101           .help = "VHDX format type, can be either 'dynamic' or 'fixed'. "\
2102                   "Default is 'dynamic'."
2103       },
2104       {
2105           .name = VHDX_BLOCK_OPT_ZERO,
2106           .type = QEMU_OPT_BOOL,
2107           .help = "Force use of payload blocks of type 'ZERO'. "\
2108                   "Non-standard, but default.  Do not set to 'off' when "\
2109                   "using 'qemu-img convert' with subformat=dynamic."
2110       },
2111       { NULL }
2112    }
2113};
2114
2115static BlockDriver bdrv_vhdx = {
2116    .format_name            = "vhdx",
2117    .instance_size          = sizeof(BDRVVHDXState),
2118    .bdrv_probe             = vhdx_probe,
2119    .bdrv_open              = vhdx_open,
2120    .bdrv_close             = vhdx_close,
2121    .bdrv_reopen_prepare    = vhdx_reopen_prepare,
2122    .bdrv_child_perm        = bdrv_format_default_perms,
2123    .bdrv_co_readv          = vhdx_co_readv,
2124    .bdrv_co_writev         = vhdx_co_writev,
2125    .bdrv_co_create         = vhdx_co_create,
2126    .bdrv_co_create_opts    = vhdx_co_create_opts,
2127    .bdrv_get_info          = vhdx_get_info,
2128    .bdrv_co_check          = vhdx_co_check,
2129    .bdrv_has_zero_init     = bdrv_has_zero_init_1,
2130
2131    .create_opts            = &vhdx_create_opts,
2132};
2133
2134static void bdrv_vhdx_init(void)
2135{
2136    bdrv_register(&bdrv_vhdx);
2137}
2138
2139block_init(bdrv_vhdx_init);
2140