For the fixed VHD format, round the raw image size to the next
multiple of the cylinder size. This is what qemu-img seems to be doing. Make sure to handle boundary cases where increasing the image size by 1 cyclinder's worth would also result in a change of geometry.
This commit is contained in:
parent
728d82cdd2
commit
2697d1ee89
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=284269
@ -62,6 +62,12 @@ __FBSDID("$FreeBSD$");
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#define VHD_SECTOR_SIZE 512
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#define VHD_BLOCK_SIZE (4096 * VHD_SECTOR_SIZE) /* 2MB blocks */
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struct vhd_geom {
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uint16_t cylinders;
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uint8_t heads;
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uint8_t sectors;
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};
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struct vhd_footer {
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uint64_t cookie;
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#define VHD_FOOTER_COOKIE 0x636f6e6563746978ULL
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@ -80,9 +86,7 @@ struct vhd_footer {
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#define VHD_CREATOR_OS 0x46425344
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uint64_t original_size;
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uint64_t current_size;
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uint16_t cylinders;
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uint8_t heads;
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uint8_t sectors;
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struct vhd_geom geometry;
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uint32_t disk_type;
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#define VHD_DISK_TYPE_FIXED 2
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#define VHD_DISK_TYPE_DYNAMIC 3
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@ -111,7 +115,7 @@ vhd_checksum(void *buf, size_t sz)
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}
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static void
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vhd_geometry(struct vhd_footer *footer, uint64_t image_size)
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vhd_geometry(uint64_t image_size, struct vhd_geom *geom)
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{
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lba_t imgsz;
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long cth;
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@ -120,9 +124,9 @@ vhd_geometry(struct vhd_footer *footer, uint64_t image_size)
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if (nheads > 1 && nheads < 256 &&
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nsecs > 1 && nsecs < 256 &&
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ncyls < 65536) {
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be16enc(&footer->cylinders, ncyls);
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footer->heads = nheads;
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footer->sectors = nsecs;
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geom->cylinders = ncyls;
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geom->heads = nheads;
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geom->sectors = nsecs;
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return;
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}
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@ -130,27 +134,27 @@ vhd_geometry(struct vhd_footer *footer, uint64_t image_size)
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if (imgsz > 65536 * 16 * 255)
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imgsz = 65536 * 16 * 255;
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if (imgsz >= 65535 * 16 * 63) {
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be16enc(&footer->cylinders, imgsz / (16 * 255));
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footer->heads = 16;
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footer->sectors = 255;
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geom->cylinders = imgsz / (16 * 255);
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geom->heads = 16;
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geom->sectors = 255;
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return;
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}
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footer->sectors = 17;
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geom->sectors = 17;
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cth = imgsz / 17;
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footer->heads = (cth + 1023) / 1024;
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if (footer->heads < 4)
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footer->heads = 4;
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if (cth >= (footer->heads * 1024) || footer->heads > 16) {
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footer->heads = 16;
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footer->sectors = 31;
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geom->heads = (cth + 1023) / 1024;
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if (geom->heads < 4)
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geom->heads = 4;
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if (cth >= (geom->heads * 1024) || geom->heads > 16) {
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geom->heads = 16;
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geom->sectors = 31;
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cth = imgsz / 31;
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}
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if (cth >= (footer->heads * 1024)) {
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footer->heads = 16;
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footer->sectors = 63;
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if (cth >= (geom->heads * 1024)) {
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geom->heads = 16;
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geom->sectors = 63;
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cth = imgsz / 63;
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}
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be16enc(&footer->cylinders, cth / footer->heads);
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geom->cylinders = cth / geom->heads;
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}
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static uint32_t
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@ -198,30 +202,14 @@ vhd_make_footer(struct vhd_footer *footer, uint64_t image_size,
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be32enc(&footer->creator_os, VHD_CREATOR_OS);
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be64enc(&footer->original_size, image_size);
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be64enc(&footer->current_size, image_size);
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vhd_geometry(footer, image_size);
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vhd_geometry(image_size, &footer->geometry);
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be16enc(&footer->geometry.cylinders, footer->geometry.cylinders);
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be32enc(&footer->disk_type, disk_type);
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mkimg_uuid(&id);
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vhd_uuid_enc(&footer->id, &id);
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be32enc(&footer->checksum, vhd_checksum(footer, sizeof(*footer)));
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}
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/*
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* We round the image size to 2MB for both the dynamic and
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* fixed VHD formats. For dynamic VHD, this is needed to
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* have the image size be a multiple of the grain size. For
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* fixed VHD this is not really needed, but makes sure that
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* it's easy to convert from fixed VHD to dynamic VHD.
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*/
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static int
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vhd_resize(lba_t imgsz)
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{
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uint64_t imagesz;
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imagesz = imgsz * secsz;
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imagesz = (imagesz + VHD_BLOCK_SIZE - 1) & ~(VHD_BLOCK_SIZE - 1);
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return (image_set_size(imagesz / secsz));
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}
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/*
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* PART 2: Dynamic VHD support
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*
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@ -261,6 +249,16 @@ _Static_assert(sizeof(struct vhd_dyn_header) == VHD_SECTOR_SIZE * 2,
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"Wrong size for header");
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#endif
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static int
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vhd_dyn_resize(lba_t imgsz)
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{
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uint64_t imagesz;
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imagesz = imgsz * secsz;
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imagesz = (imagesz + VHD_BLOCK_SIZE - 1) & ~(VHD_BLOCK_SIZE - 1);
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return (image_set_size(imagesz / secsz));
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}
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static int
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vhd_dyn_write(int fd)
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{
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@ -349,16 +347,35 @@ vhd_dyn_write(int fd)
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static struct mkimg_format vhd_dyn_format = {
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.name = "vhd",
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.description = "Virtual Hard Disk",
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.resize = vhd_resize,
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.resize = vhd_dyn_resize,
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.write = vhd_dyn_write,
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};
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FORMAT_DEFINE(vhd_dyn_format);
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/*
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* PART 2: Fixed VHD
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* PART 3: Fixed VHD
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*/
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static int
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vhd_fix_resize(lba_t imgsz)
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{
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struct vhd_geom geom;
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int64_t imagesz;
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imgsz *= secsz;
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imagesz = imgsz;
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while (1) {
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vhd_geometry(imagesz, &geom);
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imagesz = (int64_t)geom.cylinders * geom.heads *
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geom.sectors * VHD_SECTOR_SIZE;
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if (imagesz >= imgsz)
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break;
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imagesz += geom.heads * geom.sectors * VHD_SECTOR_SIZE;
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}
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return (image_set_size(imagesz / secsz));
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}
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static int
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vhd_fix_write(int fd)
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{
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@ -379,7 +396,7 @@ vhd_fix_write(int fd)
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static struct mkimg_format vhd_fix_format = {
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.name = "vhdf",
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.description = "Fixed Virtual Hard Disk",
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.resize = vhd_resize,
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.resize = vhd_fix_resize,
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.write = vhd_fix_write,
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};
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