From 0444dceee48fed54e8334428fa57f9ff997736e8 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 3 Mar 2015 11:41:53 +0100 Subject: vpc: Ignore geometry for large images The CHS calculation as done per the VHD spec imposes a maximum image size of ~127 GB. Real VHD images exist that are larger than that. Apparently there are two separate non-standard ways to achieve this: You could use more heads than the spec does - this is the option that qemu-img create chooses. However, other images exist where the geometry is set to the maximum (65535/16/255), but the actual image size is larger. Until now, such images are truncated at 127 GB when opening them with qemu. This patch changes the vpc driver to ignore geometry in this case and only trust the size field in the header. Signed-off-by: Kevin Wolf [PL: Fixed maximum geometry in the commit msg] Signed-off-by: Peter Lieven Message-id: 1425379316-19639-3-git-send-email-pl@kamp.de Reviewed-by: Max Reitz Signed-off-by: Max Reitz --- block/vpc.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'block/vpc.c') diff --git a/block/vpc.c b/block/vpc.c index c8e17cb058..1c9592ccf4 100644 --- a/block/vpc.c +++ b/block/vpc.c @@ -215,12 +215,10 @@ 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 created with disk2vhd report a far higher virtual size - * than expected with the cyls * heads * sectors_per_cyl formula. - * use the footer->size instead if the image was created with - * disk2vhd. - */ - if (!strncmp(footer->creator_app, "d2v", 4)) { + /* 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->size for them. */ + if (bs->total_sectors == 65535ULL * 16 * 255) { bs->total_sectors = be64_to_cpu(footer->size) / BDRV_SECTOR_SIZE; } -- cgit v1.2.3