diff options
| -rw-r--r-- | block/vpc.c | 87 |
1 files changed, 82 insertions, 5 deletions
diff --git a/block/vpc.c b/block/vpc.c index f504536d1c..54a38a7aed 100644 --- a/block/vpc.c +++ b/block/vpc.c @@ -128,6 +128,8 @@ typedef struct BDRVVPCState { uint32_t block_size; uint32_t bitmap_size; + bool force_use_chs; + bool force_use_sz; #ifdef CACHE uint8_t *pageentry_u8; @@ -140,6 +142,22 @@ typedef struct BDRVVPCState { Error *migration_blocker; } BDRVVPCState; +#define VPC_OPT_SIZE_CALC "force_size_calc" +static QemuOptsList vpc_runtime_opts = { + .name = "vpc-runtime-opts", + .head = QTAILQ_HEAD_INITIALIZER(vpc_runtime_opts.head), + .desc = { + { + .name = VPC_OPT_SIZE_CALC, + .type = QEMU_OPT_STRING, + .help = "Force disk size calculation to use either CHS geometry, " + "or use the disk current_size specified in the VHD footer. " + "{chs, current_size}" + }, + { /* end of list */ } + } +}; + static uint32_t vpc_checksum(uint8_t* buf, size_t size) { uint32_t res = 0; @@ -159,6 +177,25 @@ static int vpc_probe(const uint8_t *buf, int buf_size, const char *filename) return 0; } +static void vpc_parse_options(BlockDriverState *bs, QemuOpts *opts, + Error **errp) +{ + BDRVVPCState *s = bs->opaque; + const char *size_calc; + + size_calc = qemu_opt_get(opts, VPC_OPT_SIZE_CALC); + + if (!size_calc) { + /* no override, use autodetect only */ + } else if (!strcmp(size_calc, "current_size")) { + s->force_use_sz = true; + } else if (!strcmp(size_calc, "chs")) { + s->force_use_chs = true; + } else { + error_setg(errp, "Invalid size calculation mode: '%s'", size_calc); + } +} + static int vpc_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { @@ -166,6 +203,9 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags, int i; VHDFooter *footer; VHDDynDiskHeader *dyndisk_header; + QemuOpts *opts = NULL; + Error *local_err = NULL; + bool use_chs; uint8_t buf[HEADER_SIZE]; uint32_t checksum; uint64_t computed_size; @@ -173,6 +213,21 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags, int disk_type = VHD_DYNAMIC; int ret; + opts = qemu_opts_create(&vpc_runtime_opts, NULL, 0, &error_abort); + qemu_opts_absorb_qdict(opts, options, &local_err); + if (local_err) { + error_propagate(errp, local_err); + ret = -EINVAL; + goto fail; + } + + vpc_parse_options(bs, opts, &local_err); + if (local_err) { + error_propagate(errp, local_err); + ret = -EINVAL; + goto fail; + } + ret = bdrv_pread(bs->file->bs, 0, s->footer_buf, HEADER_SIZE); if (ret < 0) { goto fail; @@ -218,12 +273,34 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags, bs->total_sectors = (int64_t) be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl; - /* Images that have exactly the maximum geometry are probably bigger and - * would be truncated if we adhered to the geometry for them. Rely on - * footer->current_size for them. */ - if (bs->total_sectors == VHD_MAX_GEOMETRY) { + /* Microsoft Virtual PC and Microsoft Hyper-V produce and read + * VHD image sizes differently. VPC will rely on CHS geometry, + * while Hyper-V and disk2vhd use the size specified in the footer. + * + * We use a couple of approaches to try and determine the correct method: + * look at the Creator App field, and look for images that have CHS + * geometry that is the maximum value. + * + * If the CHS geometry is the maximum CHS geometry, then we assume that + * the size is the footer->current_size to avoid truncation. Otherwise, + * we follow the table based on footer->creator_app: + * + * Known creator apps: + * 'vpc ' : CHS Virtual PC (uses disk geometry) + * 'qemu' : CHS QEMU (uses disk geometry) + * 'win ' : current_size Hyper-V + * 'd2v ' : current_size Disk2vhd + * + * The user can override the table values via drive options, however + * even with an override we will still use current_size for images + * that have CHS geometry of the maximum size. + */ + use_chs = (!!strncmp(footer->creator_app, "win ", 4) && + !!strncmp(footer->creator_app, "d2v ", 4)) || s->force_use_chs; + + if (!use_chs || bs->total_sectors == VHD_MAX_GEOMETRY || s->force_use_sz) { bs->total_sectors = be64_to_cpu(footer->current_size) / - BDRV_SECTOR_SIZE; + BDRV_SECTOR_SIZE; } /* Allow a maximum disk size of approximately 2 TB */ |