block/iscsi: fix memory corruption on iscsi resize

bs->total_sectors is not yet updated at this point. resulting
in memory corruption if the volume has grown and data is written
to the newly availble areas.

CC: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

block/iscsi.c

@@ -1512,7 +1512,8 @@ static int iscsi_truncate(BlockDriverState *bs, int64_t offset)
     if (iscsilun->allocationmap != NULL) {
         g_free(iscsilun->allocationmap);
         iscsilun->allocationmap =
-            bitmap_new(DIV_ROUND_UP(bs->total_sectors,
+            bitmap_new(DIV_ROUND_UP(sector_lun2qemu(iscsilun->num_blocks,
+                                                    iscsilun),
                                     iscsilun->cluster_sectors));
     }