From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=53497 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OZ04u-0006Rw-Rp for qemu-devel@nongnu.org; Wed, 14 Jul 2010 07:24:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OZ04t-0001Ry-5W for qemu-devel@nongnu.org; Wed, 14 Jul 2010 07:24:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40180) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OZ04s-0001Rp-VO for qemu-devel@nongnu.org; Wed, 14 Jul 2010 07:24:39 -0400 From: Kevin Wolf Date: Wed, 14 Jul 2010 13:24:04 +0200 Message-Id: <1279106653-24351-6-git-send-email-kwolf@redhat.com> In-Reply-To: <1279106653-24351-1-git-send-email-kwolf@redhat.com> References: <1279106653-24351-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [STABLE][PATCH 05/14] block/vpc: Fix conversion from size to disk geometry List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: aurelien@aurel32.net Cc: kwolf@redhat.com, qemu-devel@nongnu.org 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) --- block/vpc.c | 21 ++++++++++++--------- 1 files changed, 12 insertions(+), 9 deletions(-) diff --git a/block/vpc.c b/block/vpc.c index 950ad58..afe6f1a 100644 --- a/block/vpc.c +++ b/block/vpc.c @@ -470,9 +470,7 @@ 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; } @@ -484,9 +482,9 @@ 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; @@ -503,9 +501,14 @@ 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 -- 1.7.1.1