From b80f97e724da8388b544413d6a3dcac35d347d9b Mon Sep 17 00:00:00 2001 Message-Id: From: Jeffrey Cody Date: Wed, 28 Aug 2013 13:14:43 +0200 Subject: [PATCH 01/13] block/vpc: Fix conversion from size to disk geometry RH-Author: Jeffrey Cody Message-id: <77176e1a7e9b121b01e6e59ec71344e2b1958b6d.1377694139.git.jcody@redhat.com> Patchwork-id: 53836 O-Subject: [RHEL6.5 qemu-kvm PATCH 01/13] block/vpc: Fix conversion from size to disk geometry Bugzilla: 999779 RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Kevin Wolf RH-Acked-by: Fam Zheng From: Stefan Weil The VHD algorithm calculates a disk geometry which is usually smaller than the requested size. QEMU tried to round up but failed for certain sizes: qemu-img create -f vpc disk.vpc 9437184 would create an image with 9435136 bytes (which is too small for qemu-img convert). Instead of hacking the geometry algorithm, the patch increases the number of sectors until we get enough sectors. Cc: Kevin Wolf Signed-off-by: Stefan Weil Signed-off-by: Kevin Wolf (cherry picked from commit dede4188cc817a039154ed2ecd7f3285f6b94056) Signed-off-by: Jeff Cody --- block/vpc.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) Signed-off-by: Michal Novotny --- block/vpc.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/block/vpc.c b/block/vpc.c index 4dfacfd..fd79547 100644 --- a/block/vpc.c +++ b/block/vpc.c @@ -498,9 +498,7 @@ static int calculate_geometry(int64_t total_sectors, uint16_t* cyls, } } - // Note: Rounding up deviates from the Virtual PC behaviour - // However, we need this to avoid truncating images in qemu-img convert - *cyls = (cyls_times_heads + *heads - 1) / *heads; + *cyls = cyls_times_heads / *heads; return 0; } @@ -512,9 +510,9 @@ static int vpc_create(const char *filename, QEMUOptionParameter *options) struct vhd_dyndisk_header* dyndisk_header = (struct vhd_dyndisk_header*) buf; int fd, i; - uint16_t cyls; - uint8_t heads; - uint8_t secs_per_cyl; + uint16_t cyls = 0; + uint8_t heads = 0; + uint8_t secs_per_cyl = 0; size_t block_size, num_bat_entries; int64_t total_sectors = 0; @@ -531,9 +529,14 @@ static int vpc_create(const char *filename, QEMUOptionParameter *options) if (fd < 0) return -EIO; - // Calculate matching total_size and geometry - if (calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl)) - return -EFBIG; + /* Calculate matching total_size and geometry. Increase the number of + sectors requested until we get enough (or fail). */ + for (i = 0; total_sectors > (int64_t)cyls * heads * secs_per_cyl; i++) { + if (calculate_geometry(total_sectors + i, + &cyls, &heads, &secs_per_cyl)) { + return -EFBIG; + } + } total_sectors = (int64_t) cyls * heads * secs_per_cyl; // Prepare the Hard Disk Footer -- 1.7.11.7