qemu-io: Respect early image end for map bdrv_is_allocated() may report zero clusters which most probably means the image (file) is shorter than expected. Respect this case in order to avoid an infinite loop. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoît Canet <benoit.canet@nodalink.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>

diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index b224ede..d94fb1e 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c

@@ -1900,7 +1900,7 @@
 
         num_checked = MIN(nb_sectors, INT_MAX);
         ret = bdrv_is_allocated(bs, sector_num, num_checked, &num);
-        if (ret == firstret) {
+        if (ret == firstret && num) {
             *pnum += num;
         } else {
             break;
@@ -1927,6 +1927,9 @@
         if (ret < 0) {
             error_report("Failed to get allocation status: %s", strerror(-ret));
             return 0;
+        } else if (!num) {
+            error_report("Unexpected end of image");
+            return 0;
         }
 
         retstr = ret ? "    allocated" : "not allocated";