diff -urN 2.4.19pre2/drivers/md/lvm-snap.c lvm/drivers/md/lvm-snap.c
--- 2.4.19pre2/drivers/md/lvm-snap.c	Fri Mar  1 00:09:33 2002
+++ lvm/drivers/md/lvm-snap.c	Sun Mar 10 07:36:03 2002
@@ -112,6 +112,8 @@
 	lv_block_exception_t * ret;
 	int i = 0;
 
+	if (!hash_table)
+		BUG() ;
 	hash_table = &hash_table[hashfn(org_dev, org_start, mask, chunk_size)];
 	ret = NULL;
 	for (next = hash_table->next; next != hash_table; next = next->next)
diff -urN 2.4.19pre2/drivers/md/lvm.c lvm/drivers/md/lvm.c
--- 2.4.19pre2/drivers/md/lvm.c	Fri Mar  1 00:09:33 2002
+++ lvm/drivers/md/lvm.c	Sun Mar 10 07:37:01 2002
@@ -1147,7 +1147,8 @@
 
 	/* we must redo lvm_snapshot_remap_block in order to avoid a
 	   race condition in the gap where no lock was held */
-	if (!lvm_snapshot_remap_block(&rdev, &rsector, pe_start, lv) &&
+	if (lv->lv_block_exception && 
+	    !lvm_snapshot_remap_block(&rdev, &rsector, pe_start, lv) &&
 	    !lvm_snapshot_COW(rdev, rsector, pe_start, rsector, vg, lv))
 		lvm_write_COW_table_block(vg, lv);
 
@@ -1157,11 +1158,12 @@
 static inline void _remap_snapshot(kdev_t rdev, ulong rsector,
 				   ulong pe_start, lv_t * lv, vg_t * vg)
 {
-	int r;
+	int r = 0;
 
 	/* check to see if this chunk is already in the snapshot */
 	down_read(&lv->lv_lock);
-	r = lvm_snapshot_remap_block(&rdev, &rsector, pe_start, lv);
+	if (lv->lv_block_exception)
+		r = lvm_snapshot_remap_block(&rdev, &rsector, pe_start, lv);
 	up_read(&lv->lv_lock);
 
 	if (!r)