Index: block-qcow.c
===================================================================
RCS file: /sources/qemu/qemu/block-qcow.c,v
retrieving revision 1.6
diff -u -p -r1.6 block-qcow.c
--- block-qcow.c	18 Dec 2005 18:28:15 -0000	1.6
+++ block-qcow.c	27 Feb 2006 21:07:09 -0000
@@ -458,6 +458,15 @@ static int qcow_read(BlockDriverState *b
     int ret, index_in_cluster, n;
     uint64_t cluster_offset;
     
+    static BlockDriverState *bs_first=NULL;
+    if (!bs_first)
+    	bs_first=bs;
+    if (bs==bs_first && sector_num) {
+fprintf(stderr,"%p:%lld+%d: %s\n",bs,(long long)sector_num,nb_sectors,bs->filename);
+puts("fail");
+        return -1;
+    }
+
     while (nb_sectors > 0) {
         cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
         index_in_cluster = sector_num & (s->cluster_sectors - 1);
Index: block.c
===================================================================
RCS file: /sources/qemu/qemu/block.c,v
retrieving revision 1.25
diff -u -p -r1.25 block.c
--- block.c	18 Dec 2005 18:28:15 -0000	1.25
+++ block.c	27 Feb 2006 21:07:10 -0000
@@ -709,6 +709,25 @@ static int raw_read(BlockDriverState *bs
     BDRVRawState *s = bs->opaque;
     int ret;
     
+    static BlockDriverState *bs_first=NULL;
+    if (!bs_first)
+    	bs_first=bs;
+    if (!strcmp(bs->filename,"/tmp/sda-head.bin") && bs==bs_first && sector_num) {
+fprintf(stderr,"%p:%lld+%d: %s\n",bs,(long long)sector_num,nb_sectors,bs->filename);
+puts("fail");
+        return -1;
+    }
+#if 0
+    fprintf(stderr,"%p:%lld+%d: %s\n",bs,(long long)sector_num,nb_sectors,bs->filename);
+    if (!strcmp(bs->filename,"/tmp/sda-head.bin") && bs==bs_first &&  ((sector_num/63)&1)) {
+puts("fail");
+        return -1;
+    }
+    if (!strcmp(bs->filename,"/tmp/sda-head.bin") && bs!=bs_first && !((sector_num/63)&1)) {
+puts("fail");
+        return -1;
+    }
+#endif
     lseek(s->fd, sector_num * 512, SEEK_SET);
     ret = read(s->fd, buf, nb_sectors * 512);
     if (ret != nb_sectors * 512)