block-vpc: Don't silently create smaller image than requested
The algorithm from the VHD specification for CHS calculation silently limits
images to 127 GB which may confuse a user who requested a larger image. Better
output an error message and abort.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7109 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/block-vpc.c b/block-vpc.c
index 7ae5202..71a171d 100644
--- a/block-vpc.c
+++ b/block-vpc.c
@@ -433,14 +433,16 @@
*
* Note that the geometry doesn't always exactly match total_sectors but
* may round it down.
+ *
+ * Returns 0 on success, -EFBIG if the size is larger than 127 GB
*/
-static void calculate_geometry(int64_t total_sectors, uint16_t* cyls,
+static int calculate_geometry(int64_t total_sectors, uint16_t* cyls,
uint8_t* heads, uint8_t* secs_per_cyl)
{
uint32_t cyls_times_heads;
if (total_sectors > 65535 * 16 * 255)
- total_sectors = 65535 * 16 * 255;
+ return -EFBIG;
if (total_sectors > 65535 * 16 * 63) {
*secs_per_cyl = 255;
@@ -470,6 +472,8 @@
// 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;
+
+ return 0;
}
static int vpc_create(const char *filename, int64_t total_sectors,
@@ -493,7 +497,8 @@
return -EIO;
// Calculate matching total_size and geometry
- calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl);
+ if (calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl))
+ return -EFBIG;
total_sectors = (int64_t) cyls * heads * secs_per_cyl;
// Prepare the Hard Disk Footer
