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 "qemu/bswap.h"
  26#include "block/vhdx.h"
  27#include "migration/blocker.h"
  28#include "qemu/uuid.h"
  29
  30/* Options for VHDX creation */
  31
  32#define VHDX_BLOCK_OPT_LOG_SIZE   "log_size"
  33#define VHDX_BLOCK_OPT_BLOCK_SIZE "block_size"
  34#define VHDX_BLOCK_OPT_ZERO "block_state_zero"
  35
  36typedef enum VHDXImageType {
  37    VHDX_TYPE_DYNAMIC = 0,
  38    VHDX_TYPE_FIXED,
  39    VHDX_TYPE_DIFFERENCING,   /* Currently unsupported */
  40} VHDXImageType;
  41
  42/* Several metadata and region table data entries are identified by
  43 * guids in  a MS-specific GUID format. */
  44
  45
  46/* ------- Known Region Table GUIDs ---------------------- */
  47static const MSGUID bat_guid =      { .data1 = 0x2dc27766,
  48                                      .data2 = 0xf623,
  49                                      .data3 = 0x4200,
  50                                      .data4 = { 0x9d, 0x64, 0x11, 0x5e,
  51                                                 0x9b, 0xfd, 0x4a, 0x08} };
  52
  53static const MSGUID metadata_guid = { .data1 = 0x8b7ca206,
  54                                      .data2 = 0x4790,
  55                                      .data3 = 0x4b9a,
  56                                      .data4 = { 0xb8, 0xfe, 0x57, 0x5f,
  57                                                 0x05, 0x0f, 0x88, 0x6e} };
  58
  59
  60
  61/* ------- Known Metadata Entry GUIDs ---------------------- */
  62static const MSGUID file_param_guid =   { .data1 = 0xcaa16737,
  63                                          .data2 = 0xfa36,
  64                                          .data3 = 0x4d43,
  65                                          .data4 = { 0xb3, 0xb6, 0x33, 0xf0,
  66                                                     0xaa, 0x44, 0xe7, 0x6b} };
  67
  68static const MSGUID virtual_size_guid = { .data1 = 0x2FA54224,
  69                                          .data2 = 0xcd1b,
  70                                          .data3 = 0x4876,
  71                                          .data4 = { 0xb2, 0x11, 0x5d, 0xbe,
  72                                                     0xd8, 0x3b, 0xf4, 0xb8} };
  73
  74static const MSGUID page83_guid =       { .data1 = 0xbeca12ab,
  75                                          .data2 = 0xb2e6,
  76                                          .data3 = 0x4523,
  77                                          .data4 = { 0x93, 0xef, 0xc3, 0x09,
  78                                                     0xe0, 0x00, 0xc7, 0x46} };
  79
  80
  81static const MSGUID phys_sector_guid =  { .data1 = 0xcda348c7,
  82                                          .data2 = 0x445d,
  83                                          .data3 = 0x4471,
  84                                          .data4 = { 0x9c, 0xc9, 0xe9, 0x88,
  85                                                     0x52, 0x51, 0xc5, 0x56} };
  86
  87static const MSGUID parent_locator_guid = { .data1 = 0xa8d35f2d,
  88                                            .data2 = 0xb30b,
  89                                            .data3 = 0x454d,
  90                                            .data4 = { 0xab, 0xf7, 0xd3,
  91                                                       0xd8, 0x48, 0x34,
  92                                                       0xab, 0x0c} };
  93
  94static const MSGUID logical_sector_guid = { .data1 = 0x8141bf1d,
  95                                            .data2 = 0xa96f,
  96                                            .data3 = 0x4709,
  97                                            .data4 = { 0xba, 0x47, 0xf2,
  98                                                       0x33, 0xa8, 0xfa,
  99                                                       0xab, 0x5f} };
 100
 101/* Each parent type must have a valid GUID; this is for parent images
 102 * of type 'VHDX'.  If we were to allow e.g. a QCOW2 parent, we would
 103 * need to make up our own QCOW2 GUID type */
 104static const MSGUID parent_vhdx_guid __attribute__((unused))
 105                                     = { .data1 = 0xb04aefb7,
 106                                         .data2 = 0xd19e,
 107                                         .data3 = 0x4a81,
 108                                         .data4 = { 0xb7, 0x89, 0x25, 0xb8,
 109                                                    0xe9, 0x44, 0x59, 0x13} };
 110
 111
 112#define META_FILE_PARAMETER_PRESENT      0x01
 113#define META_VIRTUAL_DISK_SIZE_PRESENT   0x02
 114#define META_PAGE_83_PRESENT             0x04
 115#define META_LOGICAL_SECTOR_SIZE_PRESENT 0x08
 116#define META_PHYS_SECTOR_SIZE_PRESENT    0x10
 117#define META_PARENT_LOCATOR_PRESENT      0x20
 118
 119#define META_ALL_PRESENT    \
 120    (META_FILE_PARAMETER_PRESENT | META_VIRTUAL_DISK_SIZE_PRESENT | \
 121     META_PAGE_83_PRESENT | META_LOGICAL_SECTOR_SIZE_PRESENT | \
 122     META_PHYS_SECTOR_SIZE_PRESENT)
 123
 124
 125typedef struct VHDXSectorInfo {
 126    uint32_t bat_idx;       /* BAT entry index */
 127    uint32_t sectors_avail; /* sectors available in payload block */
 128    uint32_t bytes_left;    /* bytes left in the block after data to r/w */
 129    uint32_t bytes_avail;   /* bytes available in payload block */
 130    uint64_t file_offset;   /* absolute offset in bytes, in file */
 131    uint64_t block_offset;  /* block offset, in bytes */
 132} VHDXSectorInfo;
 133
 134/* Calculates new checksum.
 135 *
 136 * Zero is substituted during crc calculation for the original crc field
 137 * crc_offset: byte offset in buf of the buffer crc
 138 * buf: buffer pointer
 139 * size: size of buffer (must be > crc_offset+4)
 140 *
 141 * Note: The buffer should have all multi-byte data in little-endian format,
 142 *       and the resulting checksum is in little endian format.
 143 */
 144uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset)
 145{
 146    uint32_t crc;
 147
 148    assert(buf != NULL);
 149    assert(size > (crc_offset + sizeof(crc)));
 150
 151    memset(buf + crc_offset, 0, sizeof(crc));
 152    crc =  crc32c(0xffffffff, buf, size);
 153    cpu_to_le32s(&crc);
 154    memcpy(buf + crc_offset, &crc, sizeof(crc));
 155
 156    return crc;
 157}
 158
 159uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
 160                            int crc_offset)
 161{
 162    uint32_t crc_new;
 163    uint32_t crc_orig;
 164    assert(buf != NULL);
 165
 166    if (crc_offset > 0) {
 167        memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
 168        memset(buf + crc_offset, 0, sizeof(crc_orig));
 169    }
 170
 171    crc_new = crc32c(crc, buf, size);
 172    if (crc_offset > 0) {
 173        memcpy(buf + crc_offset, &crc_orig, sizeof(crc_orig));
 174    }
 175
 176    return crc_new;
 177}
 178
 179/* Validates the checksum of the buffer, with an in-place CRC.
 180 *
 181 * Zero is substituted during crc calculation for the original crc field,
 182 * and the crc field is restored afterwards.  But the buffer will be modifed
 183 * during the calculation, so this may not be not suitable for multi-threaded
 184 * use.
 185 *
 186 * crc_offset: byte offset in buf of the buffer crc
 187 * buf: buffer pointer
 188 * size: size of buffer (must be > crc_offset+4)
 189 *
 190 * returns true if checksum is valid, false otherwise
 191 */
 192bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset)
 193{
 194    uint32_t crc_orig;
 195    uint32_t crc;
 196
 197    assert(buf != NULL);
 198    assert(size > (crc_offset + 4));
 199
 200    memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
 201    crc_orig = le32_to_cpu(crc_orig);
 202
 203    crc = vhdx_checksum_calc(0xffffffff, buf, size, crc_offset);
 204
 205    return crc == crc_orig;
 206}
 207
 208
 209/*
 210 * This generates a UUID that is compliant with the MS GUIDs used
 211 * in the VHDX spec (and elsewhere).
 212 */
 213void vhdx_guid_generate(MSGUID *guid)
 214{
 215    QemuUUID uuid;
 216    assert(guid != NULL);
 217
 218    qemu_uuid_generate(&uuid);
 219    memcpy(guid, &uuid, sizeof(MSGUID));
 220}
 221
 222/* Check for region overlaps inside the VHDX image */
 223static int vhdx_region_check(BDRVVHDXState *s, uint64_t start, uint64_t length)
 224{
 225    int ret = 0;
 226    uint64_t end;
 227    VHDXRegionEntry *r;
 228
 229    end = start + length;
 230    QLIST_FOREACH(r, &s->regions, entries) {
 231        if (!((start >= r->end) || (end <= r->start))) {
 232            ret = -EINVAL;
 233            goto exit;
 234        }
 235    }
 236
 237exit:
 238    return ret;
 239}
 240
 241/* Register a region for future checks */
 242static void vhdx_region_register(BDRVVHDXState *s,
 243                                 uint64_t start, uint64_t length)
 244{
 245    VHDXRegionEntry *r;
 246
 247    r = g_malloc0(sizeof(*r));
 248
 249    r->start = start;
 250    r->end = start + length;
 251
 252    QLIST_INSERT_HEAD(&s->regions, r, entries);
 253}
 254
 255/* Free all registered regions */
 256static void vhdx_region_unregister_all(BDRVVHDXState *s)
 257{
 258    VHDXRegionEntry *r, *r_next;
 259
 260    QLIST_FOREACH_SAFE(r, &s->regions, entries, r_next) {
 261        QLIST_REMOVE(r, entries);
 262        g_free(r);
 263    }
 264}
 265
 266static void vhdx_set_shift_bits(BDRVVHDXState *s)
 267{
 268    s->logical_sector_size_bits = ctz32(s->logical_sector_size);
 269    s->sectors_per_block_bits =   ctz32(s->sectors_per_block);
 270    s->chunk_ratio_bits =         ctz64(s->chunk_ratio);
 271    s->block_size_bits =          ctz32(s->block_size);
 272}
 273
 274/*
 275 * Per the MS VHDX Specification, for every VHDX file:
 276 *      - The header section is fixed size - 1 MB
 277 *      - The header section is always the first "object"
 278 *      - The first 64KB of the header is the File Identifier
 279 *      - The first uint64 (8 bytes) is the VHDX Signature ("vhdxfile")
 280 *      - The following 512 bytes constitute a UTF-16 string identifiying the
 281 *        software that created the file, and is optional and diagnostic only.
 282 *
 283 *  Therefore, we probe by looking for the vhdxfile signature "vhdxfile"
 284 */
 285static int vhdx_probe(const uint8_t *buf, int buf_size, const char *filename)
 286{
 287    if (buf_size >= 8 && !memcmp(buf, "vhdxfile", 8)) {
 288        return 100;
 289    }
 290    return 0;
 291}
 292
 293/*
 294 * Writes the header to the specified offset.
 295 *
 296 * This will optionally read in buffer data from disk (otherwise zero-fill),
 297 * and then update the header checksum.  Header is converted to proper
 298 * endianness before being written to the specified file offset
 299 */
 300static int vhdx_write_header(BdrvChild *file, VHDXHeader *hdr,
 301                             uint64_t offset, bool read)
 302{
 303    BlockDriverState *bs_file = file->bs;
 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(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(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, 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, 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, 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, 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, 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,
 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,
 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,
 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,
 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    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
 902                               false, errp);
 903    if (!bs->file) {
 904        return -EINVAL;
 905    }
 906
 907    s->bat = NULL;
 908    s->first_visible_write = true;
 909
 910    qemu_co_mutex_init(&s->lock);
 911    QLIST_INIT(&s->regions);
 912
 913    /* validate the file signature */
 914    ret = bdrv_pread(bs->file, 0, &signature, sizeof(uint64_t));
 915    if (ret < 0) {
 916        goto fail;
 917    }
 918    if (memcmp(&signature, "vhdxfile", 8)) {
 919        ret = -EINVAL;
 920        goto fail;
 921    }
 922
 923    /* This is used for any header updates, for the file_write_guid.
 924     * The spec dictates that a new value should be used for the first
 925     * header update */
 926    vhdx_guid_generate(&s->session_guid);
 927
 928    vhdx_parse_header(bs, s, &local_err);
 929    if (local_err != NULL) {
 930        error_propagate(errp, local_err);
 931        ret = -EINVAL;
 932        goto fail;
 933    }
 934
 935    ret = vhdx_parse_log(bs, s, &s->log_replayed_on_open, errp);
 936    if (ret < 0) {
 937        goto fail;
 938    }
 939
 940    ret = vhdx_open_region_tables(bs, s);
 941    if (ret < 0) {
 942        goto fail;
 943    }
 944
 945    ret = vhdx_parse_metadata(bs, s);
 946    if (ret < 0) {
 947        goto fail;
 948    }
 949
 950    s->block_size = s->params.block_size;
 951
 952    /* the VHDX spec dictates that virtual_disk_size is always a multiple of
 953     * logical_sector_size */
 954    bs->total_sectors = s->virtual_disk_size >> s->logical_sector_size_bits;
 955
 956    vhdx_calc_bat_entries(s);
 957
 958    s->bat_offset = s->bat_rt.file_offset;
 959
 960    if (s->bat_entries > s->bat_rt.length / sizeof(VHDXBatEntry)) {
 961        /* BAT allocation is not large enough for all entries */
 962        ret = -EINVAL;
 963        goto fail;
 964    }
 965
 966    /* s->bat is freed in vhdx_close() */
 967    s->bat = qemu_try_blockalign(bs->file->bs, s->bat_rt.length);
 968    if (s->bat == NULL) {
 969        ret = -ENOMEM;
 970        goto fail;
 971    }
 972
 973    ret = bdrv_pread(bs->file, s->bat_offset, s->bat, s->bat_rt.length);
 974    if (ret < 0) {
 975        goto fail;
 976    }
 977
 978    uint64_t payblocks = s->chunk_ratio;
 979    /* endian convert, and verify populated BAT field file offsets against
 980     * region table and log entries */
 981    for (i = 0; i < s->bat_entries; i++) {
 982        le64_to_cpus(&s->bat[i]);
 983        if (payblocks--) {
 984            /* payload bat entries */
 985            if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) ==
 986                    PAYLOAD_BLOCK_FULLY_PRESENT) {
 987                ret = vhdx_region_check(s, s->bat[i] & VHDX_BAT_FILE_OFF_MASK,
 988                                        s->block_size);
 989                if (ret < 0) {
 990                    goto fail;
 991                }
 992            }
 993        } else {
 994            payblocks = s->chunk_ratio;
 995            /* Once differencing files are supported, verify sector bitmap
 996             * blocks here */
 997        }
 998    }
 999
1000    /* Disable migration when VHDX images are used */
1001    error_setg(&s->migration_blocker, "The vhdx format used by node '%s' "
1002               "does not support live migration",
1003               bdrv_get_device_or_node_name(bs));
1004    ret = migrate_add_blocker(s->migration_blocker, &local_err);
1005    if (local_err) {
1006        error_propagate(errp, local_err);
1007        error_free(s->migration_blocker);
1008        goto fail;
1009    }
1010
1011    /* TODO: differencing files */
1012
1013    return 0;
1014fail:
1015    vhdx_close(bs);
1016    return ret;
1017}
1018
1019static int vhdx_reopen_prepare(BDRVReopenState *state,
1020                               BlockReopenQueue *queue, Error **errp)
1021{
1022    return 0;
1023}
1024
1025
1026/*
1027 * Perform sector to block offset translations, to get various
1028 * sector and file offsets into the image.  See VHDXSectorInfo
1029 */
1030static void vhdx_block_translate(BDRVVHDXState *s, int64_t sector_num,
1031                                 int nb_sectors, VHDXSectorInfo *sinfo)
1032{
1033    uint32_t block_offset;
1034
1035    sinfo->bat_idx = sector_num >> s->sectors_per_block_bits;
1036    /* effectively a modulo - this gives us the offset into the block
1037     * (in sector sizes) for our sector number */
1038    block_offset = sector_num - (sinfo->bat_idx << s->sectors_per_block_bits);
1039    /* the chunk ratio gives us the interleaving of the sector
1040     * bitmaps, so we need to advance our page block index by the
1041     * sector bitmaps entry number */
1042    sinfo->bat_idx += sinfo->bat_idx >> s->chunk_ratio_bits;
1043
1044    /* the number of sectors we can read/write in this cycle */
1045    sinfo->sectors_avail = s->sectors_per_block - block_offset;
1046
1047    sinfo->bytes_left = sinfo->sectors_avail << s->logical_sector_size_bits;
1048
1049    if (sinfo->sectors_avail > nb_sectors) {
1050        sinfo->sectors_avail = nb_sectors;
1051    }
1052
1053    sinfo->bytes_avail = sinfo->sectors_avail << s->logical_sector_size_bits;
1054
1055    sinfo->file_offset = s->bat[sinfo->bat_idx] & VHDX_BAT_FILE_OFF_MASK;
1056
1057    sinfo->block_offset = block_offset << s->logical_sector_size_bits;
1058
1059    /* The file offset must be past the header section, so must be > 0 */
1060    if (sinfo->file_offset == 0) {
1061        return;
1062    }
1063
1064    /* block offset is the offset in vhdx logical sectors, in
1065     * the payload data block. Convert that to a byte offset
1066     * in the block, and add in the payload data block offset
1067     * in the file, in bytes, to get the final read address */
1068
1069    sinfo->file_offset += sinfo->block_offset;
1070}
1071
1072
1073static int vhdx_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1074{
1075    BDRVVHDXState *s = bs->opaque;
1076
1077    bdi->cluster_size = s->block_size;
1078
1079    bdi->unallocated_blocks_are_zero =
1080        (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) == 0;
1081
1082    return 0;
1083}
1084
1085
1086static coroutine_fn int vhdx_co_readv(BlockDriverState *bs, int64_t sector_num,
1087                                      int nb_sectors, QEMUIOVector *qiov)
1088{
1089    BDRVVHDXState *s = bs->opaque;
1090    int ret = 0;
1091    VHDXSectorInfo sinfo;
1092    uint64_t bytes_done = 0;
1093    QEMUIOVector hd_qiov;
1094
1095    qemu_iovec_init(&hd_qiov, qiov->niov);
1096
1097    qemu_co_mutex_lock(&s->lock);
1098
1099    while (nb_sectors > 0) {
1100        /* We are a differencing file, so we need to inspect the sector bitmap
1101         * to see if we have the data or not */
1102        if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1103            /* not supported yet */
1104            ret = -ENOTSUP;
1105            goto exit;
1106        } else {
1107            vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1108
1109            qemu_iovec_reset(&hd_qiov);
1110            qemu_iovec_concat(&hd_qiov, qiov,  bytes_done, sinfo.bytes_avail);
1111
1112            /* check the payload block state */
1113            switch (s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK) {
1114            case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1115            case PAYLOAD_BLOCK_UNDEFINED:
1116            case PAYLOAD_BLOCK_UNMAPPED:
1117            case PAYLOAD_BLOCK_UNMAPPED_v095:
1118            case PAYLOAD_BLOCK_ZERO:
1119                /* return zero */
1120                qemu_iovec_memset(&hd_qiov, 0, 0, sinfo.bytes_avail);
1121                break;
1122            case PAYLOAD_BLOCK_FULLY_PRESENT:
1123                qemu_co_mutex_unlock(&s->lock);
1124                ret = bdrv_co_readv(bs->file,
1125                                    sinfo.file_offset >> BDRV_SECTOR_BITS,
1126                                    sinfo.sectors_avail, &hd_qiov);
1127                qemu_co_mutex_lock(&s->lock);
1128                if (ret < 0) {
1129                    goto exit;
1130                }
1131                break;
1132            case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1133                /* we don't yet support difference files, fall through
1134                 * to error */
1135            default:
1136                ret = -EIO;
1137                goto exit;
1138                break;
1139            }
1140            nb_sectors -= sinfo.sectors_avail;
1141            sector_num += sinfo.sectors_avail;
1142            bytes_done += sinfo.bytes_avail;
1143        }
1144    }
1145    ret = 0;
1146exit:
1147    qemu_co_mutex_unlock(&s->lock);
1148    qemu_iovec_destroy(&hd_qiov);
1149    return ret;
1150}
1151
1152/*
1153 * Allocate a new payload block at the end of the file.
1154 *
1155 * Allocation will happen at 1MB alignment inside the file
1156 *
1157 * Returns the file offset start of the new payload block
1158 */
1159static int vhdx_allocate_block(BlockDriverState *bs, BDRVVHDXState *s,
1160                                    uint64_t *new_offset)
1161{
1162    int64_t current_len;
1163
1164    current_len = bdrv_getlength(bs->file->bs);
1165    if (current_len < 0) {
1166        return current_len;
1167    }
1168
1169    *new_offset = current_len;
1170
1171    /* per the spec, the address for a block is in units of 1MB */
1172    *new_offset = ROUND_UP(*new_offset, 1024 * 1024);
1173    if (*new_offset > INT64_MAX) {
1174        return -EINVAL;
1175    }
1176
1177    return bdrv_truncate(bs->file, *new_offset + s->block_size,
1178                         PREALLOC_MODE_OFF, NULL);
1179}
1180
1181/*
1182 * Update the BAT table entry with the new file offset, and the new entry
1183 * state */
1184static void vhdx_update_bat_table_entry(BlockDriverState *bs, BDRVVHDXState *s,
1185                                       VHDXSectorInfo *sinfo,
1186                                       uint64_t *bat_entry_le,
1187                                       uint64_t *bat_offset, int state)
1188{
1189    /* The BAT entry is a uint64, with 44 bits for the file offset in units of
1190     * 1MB, and 3 bits for the block state. */
1191    if ((state == PAYLOAD_BLOCK_ZERO)        ||
1192        (state == PAYLOAD_BLOCK_UNDEFINED)   ||
1193        (state == PAYLOAD_BLOCK_NOT_PRESENT) ||
1194        (state == PAYLOAD_BLOCK_UNMAPPED)) {
1195        s->bat[sinfo->bat_idx]  = 0;  /* For PAYLOAD_BLOCK_ZERO, the
1196                                         FileOffsetMB field is denoted as
1197                                         'reserved' in the v1.0 spec.  If it is
1198                                         non-zero, MS Hyper-V will fail to read
1199                                         the disk image */
1200    } else {
1201        s->bat[sinfo->bat_idx]  = sinfo->file_offset;
1202    }
1203
1204    s->bat[sinfo->bat_idx] |= state & VHDX_BAT_STATE_BIT_MASK;
1205
1206    *bat_entry_le = cpu_to_le64(s->bat[sinfo->bat_idx]);
1207    *bat_offset = s->bat_offset + sinfo->bat_idx * sizeof(VHDXBatEntry);
1208
1209}
1210
1211/* Per the spec, on the first write of guest-visible data to the file the
1212 * data write guid must be updated in the header */
1213int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s)
1214{
1215    int ret = 0;
1216    if (s->first_visible_write) {
1217        s->first_visible_write = false;
1218        ret = vhdx_update_headers(bs, s, true, NULL);
1219    }
1220    return ret;
1221}
1222
1223static coroutine_fn int vhdx_co_writev(BlockDriverState *bs, int64_t sector_num,
1224                                      int nb_sectors, QEMUIOVector *qiov)
1225{
1226    int ret = -ENOTSUP;
1227    BDRVVHDXState *s = bs->opaque;
1228    VHDXSectorInfo sinfo;
1229    uint64_t bytes_done = 0;
1230    uint64_t bat_entry = 0;
1231    uint64_t bat_entry_offset = 0;
1232    QEMUIOVector hd_qiov;
1233    struct iovec iov1 = { 0 };
1234    struct iovec iov2 = { 0 };
1235    int sectors_to_write;
1236    int bat_state;
1237    uint64_t bat_prior_offset = 0;
1238    bool bat_update = false;
1239
1240    qemu_iovec_init(&hd_qiov, qiov->niov);
1241
1242    qemu_co_mutex_lock(&s->lock);
1243
1244    ret = vhdx_user_visible_write(bs, s);
1245    if (ret < 0) {
1246        goto exit;
1247    }
1248
1249    while (nb_sectors > 0) {
1250        bool use_zero_buffers = false;
1251        bat_update = false;
1252        if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1253            /* not supported yet */
1254            ret = -ENOTSUP;
1255            goto exit;
1256        } else {
1257            vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1258            sectors_to_write = sinfo.sectors_avail;
1259
1260            qemu_iovec_reset(&hd_qiov);
1261            /* check the payload block state */
1262            bat_state = s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK;
1263            switch (bat_state) {
1264            case PAYLOAD_BLOCK_ZERO:
1265                /* in this case, we need to preserve zero writes for
1266                 * data that is not part of this write, so we must pad
1267                 * the rest of the buffer to zeroes */
1268
1269                /* if we are on a posix system with ftruncate() that extends
1270                 * a file, then it is zero-filled for us.  On Win32, the raw
1271                 * layer uses SetFilePointer and SetFileEnd, which does not
1272                 * zero fill AFAIK */
1273
1274                /* Queue another write of zero buffers if the underlying file
1275                 * does not zero-fill on file extension */
1276
1277                if (bdrv_has_zero_init(bs->file->bs) == 0) {
1278                    use_zero_buffers = true;
1279
1280                    /* zero fill the front, if any */
1281                    if (sinfo.block_offset) {
1282                        iov1.iov_len = sinfo.block_offset;
1283                        iov1.iov_base = qemu_blockalign(bs, iov1.iov_len);
1284                        memset(iov1.iov_base, 0, iov1.iov_len);
1285                        qemu_iovec_concat_iov(&hd_qiov, &iov1, 1, 0,
1286                                              iov1.iov_len);
1287                        sectors_to_write += iov1.iov_len >> BDRV_SECTOR_BITS;
1288                    }
1289
1290                    /* our actual data */
1291                    qemu_iovec_concat(&hd_qiov, qiov,  bytes_done,
1292                                      sinfo.bytes_avail);
1293
1294                    /* zero fill the back, if any */
1295                    if ((sinfo.bytes_avail - sinfo.block_offset) <
1296                         s->block_size) {
1297                        iov2.iov_len = s->block_size -
1298                                      (sinfo.bytes_avail + sinfo.block_offset);
1299                        iov2.iov_base = qemu_blockalign(bs, iov2.iov_len);
1300                        memset(iov2.iov_base, 0, iov2.iov_len);
1301                        qemu_iovec_concat_iov(&hd_qiov, &iov2, 1, 0,
1302                                              iov2.iov_len);
1303                        sectors_to_write += iov2.iov_len >> BDRV_SECTOR_BITS;
1304                    }
1305                }
1306                /* fall through */
1307            case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1308            case PAYLOAD_BLOCK_UNMAPPED:
1309            case PAYLOAD_BLOCK_UNMAPPED_v095:
1310            case PAYLOAD_BLOCK_UNDEFINED:
1311                bat_prior_offset = sinfo.file_offset;
1312                ret = vhdx_allocate_block(bs, s, &sinfo.file_offset);
1313                if (ret < 0) {
1314                    goto exit;
1315                }
1316                /* once we support differencing files, this may also be
1317                 * partially present */
1318                /* update block state to the newly specified state */
1319                vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1320                                            &bat_entry_offset,
1321                                            PAYLOAD_BLOCK_FULLY_PRESENT);
1322                bat_update = true;
1323                /* since we just allocated a block, file_offset is the
1324                 * beginning of the payload block. It needs to be the
1325                 * write address, which includes the offset into the block */
1326                if (!use_zero_buffers) {
1327                    sinfo.file_offset += sinfo.block_offset;
1328                }
1329                /* fall through */
1330            case PAYLOAD_BLOCK_FULLY_PRESENT:
1331                /* if the file offset address is in the header zone,
1332                 * there is a problem */
1333                if (sinfo.file_offset < (1024 * 1024)) {
1334                    ret = -EFAULT;
1335                    goto error_bat_restore;
1336                }
1337
1338                if (!use_zero_buffers) {
1339                    qemu_iovec_concat(&hd_qiov, qiov,  bytes_done,
1340                                      sinfo.bytes_avail);
1341                }
1342                /* block exists, so we can just overwrite it */
1343                qemu_co_mutex_unlock(&s->lock);
1344                ret = bdrv_co_writev(bs->file,
1345                                    sinfo.file_offset >> BDRV_SECTOR_BITS,
1346                                    sectors_to_write, &hd_qiov);
1347                qemu_co_mutex_lock(&s->lock);
1348                if (ret < 0) {
1349                    goto error_bat_restore;
1350                }
1351                break;
1352            case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1353                /* we don't yet support difference files, fall through
1354                 * to error */
1355            default:
1356                ret = -EIO;
1357                goto exit;
1358                break;
1359            }
1360
1361            if (bat_update) {
1362                /* this will update the BAT entry into the log journal, and
1363                 * then flush the log journal out to disk */
1364                ret =  vhdx_log_write_and_flush(bs, s, &bat_entry,
1365                                                sizeof(VHDXBatEntry),
1366                                                bat_entry_offset);
1367                if (ret < 0) {
1368                    goto exit;
1369                }
1370            }
1371
1372            nb_sectors -= sinfo.sectors_avail;
1373            sector_num += sinfo.sectors_avail;
1374            bytes_done += sinfo.bytes_avail;
1375
1376        }
1377    }
1378
1379    goto exit;
1380
1381error_bat_restore:
1382    if (bat_update) {
1383        /* keep metadata in sync, and restore the bat entry state
1384         * if error. */
1385        sinfo.file_offset = bat_prior_offset;
1386        vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1387                                    &bat_entry_offset, bat_state);
1388    }
1389exit:
1390    qemu_vfree(iov1.iov_base);
1391    qemu_vfree(iov2.iov_base);
1392    qemu_co_mutex_unlock(&s->lock);
1393    qemu_iovec_destroy(&hd_qiov);
1394    return ret;
1395}
1396
1397
1398
1399/*
1400 * Create VHDX Headers
1401 *
1402 * There are 2 headers, and the highest sequence number will represent
1403 * the active header
1404 */
1405static int vhdx_create_new_headers(BlockBackend *blk, uint64_t image_size,
1406                                   uint32_t log_size)
1407{
1408    BlockDriverState *bs = blk_bs(blk);
1409    BdrvChild *child;
1410    int ret = 0;
1411    VHDXHeader *hdr = NULL;
1412
1413    hdr = g_new0(VHDXHeader, 1);
1414
1415    hdr->signature       = VHDX_HEADER_SIGNATURE;
1416    hdr->sequence_number = g_random_int();
1417    hdr->log_version     = 0;
1418    hdr->version         = 1;
1419    hdr->log_length      = log_size;
1420    hdr->log_offset      = VHDX_HEADER_SECTION_END;
1421    vhdx_guid_generate(&hdr->file_write_guid);
1422    vhdx_guid_generate(&hdr->data_write_guid);
1423
1424    /* XXX Ugly way to get blk->root, but that's a feature, not a bug. This
1425     * hack makes it obvious that vhdx_write_header() bypasses the BlockBackend
1426     * here, which it really shouldn't be doing. */
1427    child = QLIST_FIRST(&bs->parents);
1428    assert(!QLIST_NEXT(child, next_parent));
1429
1430    ret = vhdx_write_header(child, hdr, VHDX_HEADER1_OFFSET, false);
1431    if (ret < 0) {
1432        goto exit;
1433    }
1434    hdr->sequence_number++;
1435    ret = vhdx_write_header(child, hdr, VHDX_HEADER2_OFFSET, false);
1436    if (ret < 0) {
1437        goto exit;
1438    }
1439
1440exit:
1441    g_free(hdr);
1442    return ret;
1443}
1444
1445#define VHDX_METADATA_ENTRY_BUFFER_SIZE \
1446                                    (sizeof(VHDXFileParameters)               +\
1447                                     sizeof(VHDXVirtualDiskSize)              +\
1448                                     sizeof(VHDXPage83Data)                   +\
1449                                     sizeof(VHDXVirtualDiskLogicalSectorSize) +\
1450                                     sizeof(VHDXVirtualDiskPhysicalSectorSize))
1451
1452/*
1453 * Create the Metadata entries.
1454 *
1455 * For more details on the entries, see section 3.5 (pg 29) in the
1456 * VHDX 1.00 specification.
1457 *
1458 * We support 5 metadata entries (all required by spec):
1459 *          File Parameters,
1460 *          Virtual Disk Size,
1461 *          Page 83 Data,
1462 *          Logical Sector Size,
1463 *          Physical Sector Size
1464 *
1465 * The first 64KB of the Metadata section is reserved for the metadata
1466 * header and entries; beyond that, the metadata items themselves reside.
1467 */
1468static int vhdx_create_new_metadata(BlockBackend *blk,
1469                                    uint64_t image_size,
1470                                    uint32_t block_size,
1471                                    uint32_t sector_size,
1472                                    uint64_t metadata_offset,
1473                                    VHDXImageType type)
1474{
1475    int ret = 0;
1476    uint32_t offset = 0;
1477    void *buffer = NULL;
1478    void *entry_buffer;
1479    VHDXMetadataTableHeader *md_table;
1480    VHDXMetadataTableEntry  *md_table_entry;
1481
1482    /* Metadata entries */
1483    VHDXFileParameters     *mt_file_params;
1484    VHDXVirtualDiskSize    *mt_virtual_size;
1485    VHDXPage83Data         *mt_page83;
1486    VHDXVirtualDiskLogicalSectorSize  *mt_log_sector_size;
1487    VHDXVirtualDiskPhysicalSectorSize *mt_phys_sector_size;
1488
1489    entry_buffer = g_malloc0(VHDX_METADATA_ENTRY_BUFFER_SIZE);
1490
1491    mt_file_params = entry_buffer;
1492    offset += sizeof(VHDXFileParameters);
1493    mt_virtual_size = entry_buffer + offset;
1494    offset += sizeof(VHDXVirtualDiskSize);
1495    mt_page83 = entry_buffer + offset;
1496    offset += sizeof(VHDXPage83Data);
1497    mt_log_sector_size = entry_buffer + offset;
1498    offset += sizeof(VHDXVirtualDiskLogicalSectorSize);
1499    mt_phys_sector_size = entry_buffer + offset;
1500
1501    mt_file_params->block_size = cpu_to_le32(block_size);
1502    if (type == VHDX_TYPE_FIXED) {
1503        mt_file_params->data_bits |= VHDX_PARAMS_LEAVE_BLOCKS_ALLOCED;
1504        cpu_to_le32s(&mt_file_params->data_bits);
1505    }
1506
1507    vhdx_guid_generate(&mt_page83->page_83_data);
1508    cpu_to_leguids(&mt_page83->page_83_data);
1509    mt_virtual_size->virtual_disk_size        = cpu_to_le64(image_size);
1510    mt_log_sector_size->logical_sector_size   = cpu_to_le32(sector_size);
1511    mt_phys_sector_size->physical_sector_size = cpu_to_le32(sector_size);
1512
1513    buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1514    md_table = buffer;
1515
1516    md_table->signature   = VHDX_METADATA_SIGNATURE;
1517    md_table->entry_count = 5;
1518    vhdx_metadata_header_le_export(md_table);
1519
1520
1521    /* This will reference beyond the reserved table portion */
1522    offset = 64 * KiB;
1523
1524    md_table_entry = buffer + sizeof(VHDXMetadataTableHeader);
1525
1526    md_table_entry[0].item_id = file_param_guid;
1527    md_table_entry[0].offset  = offset;
1528    md_table_entry[0].length  = sizeof(VHDXFileParameters);
1529    md_table_entry[0].data_bits |= VHDX_META_FLAGS_IS_REQUIRED;
1530    offset += md_table_entry[0].length;
1531    vhdx_metadata_entry_le_export(&md_table_entry[0]);
1532
1533    md_table_entry[1].item_id = virtual_size_guid;
1534    md_table_entry[1].offset  = offset;
1535    md_table_entry[1].length  = sizeof(VHDXVirtualDiskSize);
1536    md_table_entry[1].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1537                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1538    offset += md_table_entry[1].length;
1539    vhdx_metadata_entry_le_export(&md_table_entry[1]);
1540
1541    md_table_entry[2].item_id = page83_guid;
1542    md_table_entry[2].offset  = offset;
1543    md_table_entry[2].length  = sizeof(VHDXPage83Data);
1544    md_table_entry[2].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1545                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1546    offset += md_table_entry[2].length;
1547    vhdx_metadata_entry_le_export(&md_table_entry[2]);
1548
1549    md_table_entry[3].item_id = logical_sector_guid;
1550    md_table_entry[3].offset  = offset;
1551    md_table_entry[3].length  = sizeof(VHDXVirtualDiskLogicalSectorSize);
1552    md_table_entry[3].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1553                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1554    offset += md_table_entry[3].length;
1555    vhdx_metadata_entry_le_export(&md_table_entry[3]);
1556
1557    md_table_entry[4].item_id = phys_sector_guid;
1558    md_table_entry[4].offset  = offset;
1559    md_table_entry[4].length  = sizeof(VHDXVirtualDiskPhysicalSectorSize);
1560    md_table_entry[4].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1561                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1562    vhdx_metadata_entry_le_export(&md_table_entry[4]);
1563
1564    ret = blk_pwrite(blk, metadata_offset, buffer, VHDX_HEADER_BLOCK_SIZE, 0);
1565    if (ret < 0) {
1566        goto exit;
1567    }
1568
1569    ret = blk_pwrite(blk, metadata_offset + (64 * KiB), entry_buffer,
1570                     VHDX_METADATA_ENTRY_BUFFER_SIZE, 0);
1571    if (ret < 0) {
1572        goto exit;
1573    }
1574
1575
1576exit:
1577    g_free(buffer);
1578    g_free(entry_buffer);
1579    return ret;
1580}
1581
1582/* This create the actual BAT itself.  We currently only support
1583 * 'Dynamic' and 'Fixed' image types.
1584 *
1585 *  Dynamic images: default state of the BAT is all zeroes.
1586 *
1587 *  Fixed images: default state of the BAT is fully populated, with
1588 *                file offsets and state PAYLOAD_BLOCK_FULLY_PRESENT.
1589 */
1590static int vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
1591                           uint64_t image_size, VHDXImageType type,
1592                           bool use_zero_blocks, uint64_t file_offset,
1593                           uint32_t length, Error **errp)
1594{
1595    int ret = 0;
1596    uint64_t data_file_offset;
1597    uint64_t total_sectors = 0;
1598    uint64_t sector_num = 0;
1599    uint64_t unused;
1600    int block_state;
1601    VHDXSectorInfo sinfo;
1602
1603    assert(s->bat == NULL);
1604
1605    /* this gives a data start after BAT/bitmap entries, and well
1606     * past any metadata entries (with a 4 MB buffer for future
1607     * expansion */
1608    data_file_offset = file_offset + length + 5 * MiB;
1609    total_sectors = image_size >> s->logical_sector_size_bits;
1610
1611    if (type == VHDX_TYPE_DYNAMIC) {
1612        /* All zeroes, so we can just extend the file - the end of the BAT
1613         * is the furthest thing we have written yet */
1614        ret = blk_truncate(blk, data_file_offset, PREALLOC_MODE_OFF, errp);
1615        if (ret < 0) {
1616            goto exit;
1617        }
1618    } else if (type == VHDX_TYPE_FIXED) {
1619        ret = blk_truncate(blk, data_file_offset + image_size,
1620                           PREALLOC_MODE_OFF, errp);
1621        if (ret < 0) {
1622            goto exit;
1623        }
1624    } else {
1625        error_setg(errp, "Unsupported image type");
1626        ret = -ENOTSUP;
1627        goto exit;
1628    }
1629
1630    if (type == VHDX_TYPE_FIXED ||
1631                use_zero_blocks ||
1632                bdrv_has_zero_init(blk_bs(blk)) == 0) {
1633        /* for a fixed file, the default BAT entry is not zero */
1634        s->bat = g_try_malloc0(length);
1635        if (length && s->bat == NULL) {
1636            error_setg(errp, "Failed to allocate memory for the BAT");
1637            ret = -ENOMEM;
1638            goto exit;
1639        }
1640        block_state = type == VHDX_TYPE_FIXED ? PAYLOAD_BLOCK_FULLY_PRESENT :
1641                                                PAYLOAD_BLOCK_NOT_PRESENT;
1642        block_state = use_zero_blocks ? PAYLOAD_BLOCK_ZERO : block_state;
1643        /* fill the BAT by emulating sector writes of sectors_per_block size */
1644        while (sector_num < total_sectors) {
1645            vhdx_block_translate(s, sector_num, s->sectors_per_block, &sinfo);
1646            sinfo.file_offset = data_file_offset +
1647                                (sector_num << s->logical_sector_size_bits);
1648            sinfo.file_offset = ROUND_UP(sinfo.file_offset, MiB);
1649            vhdx_update_bat_table_entry(blk_bs(blk), s, &sinfo, &unused, &unused,
1650                                        block_state);
1651            cpu_to_le64s(&s->bat[sinfo.bat_idx]);
1652            sector_num += s->sectors_per_block;
1653        }
1654        ret = blk_pwrite(blk, file_offset, s->bat, length, 0);
1655        if (ret < 0) {
1656            error_setg_errno(errp, -ret, "Failed to write the BAT");
1657            goto exit;
1658        }
1659    }
1660
1661
1662
1663exit:
1664    g_free(s->bat);
1665    return ret;
1666}
1667
1668/* Creates the region table header, and region table entries.
1669 * There are 2 supported region table entries: BAT, and Metadata/
1670 *
1671 * As the calculations for the BAT region table are also needed
1672 * to create the BAT itself, we will also cause the BAT to be
1673 * created.
1674 */
1675static int vhdx_create_new_region_table(BlockBackend *blk,
1676                                        uint64_t image_size,
1677                                        uint32_t block_size,
1678                                        uint32_t sector_size,
1679                                        uint32_t log_size,
1680                                        bool use_zero_blocks,
1681                                        VHDXImageType type,
1682                                        uint64_t *metadata_offset,
1683                                        Error **errp)
1684{
1685    int ret = 0;
1686    uint32_t offset = 0;
1687    void *buffer = NULL;
1688    uint64_t bat_file_offset;
1689    uint32_t bat_length;
1690    BDRVVHDXState *s = NULL;
1691    VHDXRegionTableHeader *region_table;
1692    VHDXRegionTableEntry *rt_bat;
1693    VHDXRegionTableEntry *rt_metadata;
1694
1695    assert(metadata_offset != NULL);
1696
1697    /* Populate enough of the BDRVVHDXState to be able to use the
1698     * pre-existing BAT calculation, translation, and update functions */
1699    s = g_new0(BDRVVHDXState, 1);
1700
1701    s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
1702                     (uint64_t) sector_size / (uint64_t) block_size;
1703
1704    s->sectors_per_block = block_size / sector_size;
1705    s->virtual_disk_size = image_size;
1706    s->block_size = block_size;
1707    s->logical_sector_size = sector_size;
1708
1709    vhdx_set_shift_bits(s);
1710
1711    vhdx_calc_bat_entries(s);
1712
1713    /* At this point the VHDX state is populated enough for creation */
1714
1715    /* a single buffer is used so we can calculate the checksum over the
1716     * entire 64KB block */
1717    buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1718    region_table = buffer;
1719    offset += sizeof(VHDXRegionTableHeader);
1720    rt_bat = buffer + offset;
1721    offset += sizeof(VHDXRegionTableEntry);
1722    rt_metadata  = buffer + offset;
1723
1724    region_table->signature = VHDX_REGION_SIGNATURE;
1725    region_table->entry_count = 2;   /* BAT and Metadata */
1726
1727    rt_bat->guid        = bat_guid;
1728    rt_bat->length      = ROUND_UP(s->bat_entries * sizeof(VHDXBatEntry), MiB);
1729    rt_bat->file_offset = ROUND_UP(VHDX_HEADER_SECTION_END + log_size, MiB);
1730    s->bat_offset = rt_bat->file_offset;
1731
1732    rt_metadata->guid        = metadata_guid;
1733    rt_metadata->file_offset = ROUND_UP(rt_bat->file_offset + rt_bat->length,
1734                                        MiB);
1735    rt_metadata->length      = 1 * MiB; /* min size, and more than enough */
1736    *metadata_offset = rt_metadata->file_offset;
1737
1738    bat_file_offset = rt_bat->file_offset;
1739    bat_length = rt_bat->length;
1740
1741    vhdx_region_header_le_export(region_table);
1742    vhdx_region_entry_le_export(rt_bat);
1743    vhdx_region_entry_le_export(rt_metadata);
1744
1745    vhdx_update_checksum(buffer, VHDX_HEADER_BLOCK_SIZE,
1746                         offsetof(VHDXRegionTableHeader, checksum));
1747
1748
1749    /* The region table gives us the data we need to create the BAT,
1750     * so do that now */
1751    ret = vhdx_create_bat(blk, s, image_size, type, use_zero_blocks,
1752                          bat_file_offset, bat_length, errp);
1753    if (ret < 0) {
1754        goto exit;
1755    }
1756
1757    /* Now write out the region headers to disk */
1758    ret = blk_pwrite(blk, VHDX_REGION_TABLE_OFFSET, buffer,
1759                     VHDX_HEADER_BLOCK_SIZE, 0);
1760    if (ret < 0) {
1761        error_setg_errno(errp, -ret, "Failed to write first region table");
1762        goto exit;
1763    }
1764
1765    ret = blk_pwrite(blk, VHDX_REGION_TABLE2_OFFSET, buffer,
1766                     VHDX_HEADER_BLOCK_SIZE, 0);
1767    if (ret < 0) {
1768        error_setg_errno(errp, -ret, "Failed to write second region table");
1769        goto exit;
1770    }
1771
1772exit:
1773    g_free(s);
1774    g_free(buffer);
1775    return ret;
1776}
1777
1778/* We need to create the following elements:
1779 *
1780 *    .-----------------------------------------------------------------.
1781 *    |   (A)    |   (B)    |    (C)    |     (D)       |     (E)       |
1782 *    |  File ID |  Header1 |  Header 2 |  Region Tbl 1 |  Region Tbl 2 |
1783 *    |          |          |           |               |               |
1784 *    .-----------------------------------------------------------------.
1785 *    0         64KB      128KB       192KB           256KB           320KB
1786 *
1787 *
1788 *    .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1789 *    |     (F)     |     (G)       |    (H)    |                        |
1790 *    | Journal Log |  BAT / Bitmap |  Metadata |  .... data ......      |
1791 *    |             |               |           |                        |
1792 *    .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1793 *   1MB
1794 */
1795static int vhdx_create(const char *filename, QemuOpts *opts, Error **errp)
1796{
1797    int ret = 0;
1798    uint64_t image_size = (uint64_t) 2 * GiB;
1799    uint32_t log_size   = 1 * MiB;
1800    uint32_t block_size = 0;
1801    uint64_t signature;
1802    uint64_t metadata_offset;
1803    bool use_zero_blocks = false;
1804
1805    gunichar2 *creator = NULL;
1806    glong creator_items;
1807    BlockBackend *blk;
1808    char *type = NULL;
1809    VHDXImageType image_type;
1810    Error *local_err = NULL;
1811
1812    image_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
1813                          BDRV_SECTOR_SIZE);
1814    log_size = qemu_opt_get_size_del(opts, VHDX_BLOCK_OPT_LOG_SIZE, 0);
1815    block_size = qemu_opt_get_size_del(opts, VHDX_BLOCK_OPT_BLOCK_SIZE, 0);
1816    type = qemu_opt_get_del(opts, BLOCK_OPT_SUBFMT);
1817    use_zero_blocks = qemu_opt_get_bool_del(opts, VHDX_BLOCK_OPT_ZERO, true);
1818
1819    if (image_size > VHDX_MAX_IMAGE_SIZE) {
1820        error_setg_errno(errp, EINVAL, "Image size too large; max of 64TB");
1821        ret = -EINVAL;
1822        goto exit;
1823    }
1824
1825    if (type == NULL) {
1826        type = g_strdup("dynamic");
1827    }
1828
1829    if (!strcmp(type, "dynamic")) {
1830        image_type = VHDX_TYPE_DYNAMIC;
1831    } else if (!strcmp(type, "fixed")) {
1832        image_type = VHDX_TYPE_FIXED;
1833    } else if (!strcmp(type, "differencing")) {
1834        error_setg_errno(errp, ENOTSUP,
1835                         "Differencing files not yet supported");
1836        ret = -ENOTSUP;
1837        goto exit;
1838    } else {
1839        error_setg(errp, "Invalid subformat '%s'", type);
1840        ret = -EINVAL;
1841        goto exit;
1842    }
1843
1844    /* These are pretty arbitrary, and mainly designed to keep the BAT
1845     * size reasonable to load into RAM */
1846    if (block_size == 0) {
1847        if (image_size > 32 * TiB) {
1848            block_size = 64 * MiB;
1849        } else if (image_size > (uint64_t) 100 * GiB) {
1850            block_size = 32 * MiB;
1851        } else if (image_size > 1 * GiB) {
1852            block_size = 16 * MiB;
1853        } else {
1854            block_size = 8 * MiB;
1855        }
1856    }
1857
1858
1859    /* make the log size close to what was specified, but must be
1860     * min 1MB, and multiple of 1MB */
1861    log_size = ROUND_UP(log_size, MiB);
1862
1863    block_size = ROUND_UP(block_size, MiB);
1864    block_size = block_size > VHDX_BLOCK_SIZE_MAX ? VHDX_BLOCK_SIZE_MAX :
1865                                                    block_size;
1866
1867    ret = bdrv_create_file(filename, opts, &local_err);
1868    if (ret < 0) {
1869        error_propagate(errp, local_err);
1870        goto exit;
1871    }
1872
1873    blk = blk_new_open(filename, NULL, NULL,
1874                       BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL,
1875                       &local_err);
1876    if (blk == NULL) {
1877        error_propagate(errp, local_err);
1878        ret = -EIO;
1879        goto exit;
1880    }
1881
1882    blk_set_allow_write_beyond_eof(blk, true);
1883
1884    /* Create (A) */
1885
1886    /* The creator field is optional, but may be useful for
1887     * debugging / diagnostics */
1888    creator = g_utf8_to_utf16("QEMU v" QEMU_VERSION, -1, NULL,
1889                              &creator_items, NULL);
1890    signature = cpu_to_le64(VHDX_FILE_SIGNATURE);
1891    ret = blk_pwrite(blk, VHDX_FILE_ID_OFFSET, &signature, sizeof(signature),
1892                     0);
1893    if (ret < 0) {
1894        error_setg_errno(errp, -ret, "Failed to write file signature");
1895        goto delete_and_exit;
1896    }
1897    if (creator) {
1898        ret = blk_pwrite(blk, VHDX_FILE_ID_OFFSET + sizeof(signature),
1899                         creator, creator_items * sizeof(gunichar2), 0);
1900        if (ret < 0) {
1901            error_setg_errno(errp, -ret, "Failed to write creator field");
1902            goto delete_and_exit;
1903        }
1904    }
1905
1906
1907    /* Creates (B),(C) */
1908    ret = vhdx_create_new_headers(blk, image_size, log_size);
1909    if (ret < 0) {
1910        error_setg_errno(errp, -ret, "Failed to write image headers");
1911        goto delete_and_exit;
1912    }
1913
1914    /* Creates (D),(E),(G) explicitly. (F) created as by-product */
1915    ret = vhdx_create_new_region_table(blk, image_size, block_size, 512,
1916                                       log_size, use_zero_blocks, image_type,
1917                                       &metadata_offset, errp);
1918    if (ret < 0) {
1919        goto delete_and_exit;
1920    }
1921
1922    /* Creates (H) */
1923    ret = vhdx_create_new_metadata(blk, image_size, block_size, 512,
1924                                   metadata_offset, image_type);
1925    if (ret < 0) {
1926        error_setg_errno(errp, -ret, "Failed to initialize metadata");
1927        goto delete_and_exit;
1928    }
1929
1930
1931delete_and_exit:
1932    blk_unref(blk);
1933exit:
1934    g_free(type);
1935    g_free(creator);
1936    return ret;
1937}
1938
1939/* If opened r/w, the VHDX driver will automatically replay the log,
1940 * if one is present, inside the vhdx_open() call.
1941 *
1942 * If qemu-img check -r all is called, the image is automatically opened
1943 * r/w and any log has already been replayed, so there is nothing (currently)
1944 * for us to do here
1945 */
1946static int vhdx_check(BlockDriverState *bs, BdrvCheckResult *result,
1947                       BdrvCheckMode fix)
1948{
1949    BDRVVHDXState *s = bs->opaque;
1950
1951    if (s->log_replayed_on_open) {
1952        result->corruptions_fixed++;
1953    }
1954    return 0;
1955}
1956
1957static QemuOptsList vhdx_create_opts = {
1958    .name = "vhdx-create-opts",
1959    .head = QTAILQ_HEAD_INITIALIZER(vhdx_create_opts.head),
1960    .desc = {
1961        {
1962           .name = BLOCK_OPT_SIZE,
1963           .type = QEMU_OPT_SIZE,
1964           .help = "Virtual disk size; max of 64TB."
1965       },
1966       {
1967           .name = VHDX_BLOCK_OPT_LOG_SIZE,
1968           .type = QEMU_OPT_SIZE,
1969           .def_value_str = stringify(DEFAULT_LOG_SIZE),
1970           .help = "Log size; min 1MB."
1971       },
1972       {
1973           .name = VHDX_BLOCK_OPT_BLOCK_SIZE,
1974           .type = QEMU_OPT_SIZE,
1975           .def_value_str = stringify(0),
1976           .help = "Block Size; min 1MB, max 256MB. " \
1977                   "0 means auto-calculate based on image size."
1978       },
1979       {
1980           .name = BLOCK_OPT_SUBFMT,
1981           .type = QEMU_OPT_STRING,
1982           .help = "VHDX format type, can be either 'dynamic' or 'fixed'. "\
1983                   "Default is 'dynamic'."
1984       },
1985       {
1986           .name = VHDX_BLOCK_OPT_ZERO,
1987           .type = QEMU_OPT_BOOL,
1988           .help = "Force use of payload blocks of type 'ZERO'. "\
1989                   "Non-standard, but default.  Do not set to 'off' when "\
1990                   "using 'qemu-img convert' with subformat=dynamic."
1991       },
1992       { NULL }
1993    }
1994};
1995
1996static BlockDriver bdrv_vhdx = {
1997    .format_name            = "vhdx",
1998    .instance_size          = sizeof(BDRVVHDXState),
1999    .bdrv_probe             = vhdx_probe,
2000    .bdrv_open              = vhdx_open,
2001    .bdrv_close             = vhdx_close,
2002    .bdrv_reopen_prepare    = vhdx_reopen_prepare,
2003    .bdrv_child_perm        = bdrv_format_default_perms,
2004    .bdrv_co_readv          = vhdx_co_readv,
2005    .bdrv_co_writev         = vhdx_co_writev,
2006    .bdrv_create            = vhdx_create,
2007    .bdrv_get_info          = vhdx_get_info,
2008    .bdrv_check             = vhdx_check,
2009    .bdrv_has_zero_init     = bdrv_has_zero_init_1,
2010
2011    .create_opts            = &vhdx_create_opts,
2012};
2013
2014static void bdrv_vhdx_init(void)
2015{
2016    bdrv_register(&bdrv_vhdx);
2017}
2018
2019block_init(bdrv_vhdx_init);
2020