File ioemu-blktap-zero-size.patch of Package xen.6117

From cb982fd919a52ff86f01025d0f92225bc7b2a956 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@suse.de>
Date: Tue, 10 Mar 2009 16:44:31 +0100
Subject: [PATCH 5/6] ioemu: Fail on too small blktap disks

The blktap infrastructure doesn't seems to be able to cope with images
that are smaller than a sector, it produced hangs for me. Such an
image isn't really useful anyway, so just fail gracefully.

Signed-off-by: Kevin Wolf <kwolf@suse.de>
---
 hw/xen_blktap.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

Index: xen-4.2.0-testing/tools/qemu-xen-traditional-dir-remote/hw/xen_blktap.c
===================================================================
--- xen-4.2.0-testing.orig/tools/qemu-xen-traditional-dir-remote/hw/xen_blktap.c
+++ xen-4.2.0-testing/tools/qemu-xen-traditional-dir-remote/hw/xen_blktap.c
@@ -256,6 +256,12 @@ static int open_disk(struct td_state *s,
 	s->size = bs->total_sectors;
 	s->sector_size = 512;
 
+	if (s->size == 0) {
+		fprintf(stderr, "Error: Disk image %s is too small\n",
+			path);
+		return -ENOMEM;
+	}
+
 	s->info = ((s->flags & TD_RDONLY) ? VDISK_READONLY : 0);
 
 #ifndef QEMU_TOOL