diff --git a/chunk-format.c b/chunk-format.c
index cdc7f39b70..be078dcca8 100644
--- a/chunk-format.c
+++ b/chunk-format.c
@@ -163,6 +163,10 @@ int read_table_of_contents(struct chunkfile *cf,
 struct pair_chunk_data {
 	const unsigned char **p;
 	size_t *size;
+
+	/* for pair_chunk_expect() only */
+	size_t record_size;
+	size_t record_nr;
 };
 
 static int pair_chunk_fn(const unsigned char *chunk_start,
@@ -175,6 +179,17 @@ static int pair_chunk_fn(const unsigned char *chunk_start,
 	return 0;
 }
 
+static int pair_chunk_expect_fn(const unsigned char *chunk_start,
+				size_t chunk_size,
+				void *data)
+{
+	struct pair_chunk_data *pcd = data;
+	if (chunk_size / pcd->record_size != pcd->record_nr)
+		return -1;
+	*pcd->p = chunk_start;
+	return 0;
+}
+
 int pair_chunk(struct chunkfile *cf,
 	       uint32_t chunk_id,
 	       const unsigned char **p,
@@ -184,6 +199,20 @@ int pair_chunk(struct chunkfile *cf,
 	return read_chunk(cf, chunk_id, pair_chunk_fn, &pcd);
 }
 
+int pair_chunk_expect(struct chunkfile *cf,
+		      uint32_t chunk_id,
+		      const unsigned char **p,
+		      size_t record_size,
+		      size_t record_nr)
+{
+	struct pair_chunk_data pcd = {
+		.p = p,
+		.record_size = record_size,
+		.record_nr = record_nr,
+	};
+	return read_chunk(cf, chunk_id, pair_chunk_expect_fn, &pcd);
+}
+
 int read_chunk(struct chunkfile *cf,
 	       uint32_t chunk_id,
 	       chunk_read_fn fn,
diff --git a/chunk-format.h b/chunk-format.h
index 14b76180ef..10806d7a9a 100644
--- a/chunk-format.h
+++ b/chunk-format.h
@@ -17,7 +17,8 @@ struct chunkfile;
  *
  * If reading a file, use a NULL 'struct hashfile *' and then call
  * read_table_of_contents(). Supply the memory-mapped data to the
- * pair_chunk() or read_chunk() methods, as appropriate.
+ * pair_chunk(), pair_chunk_expect(), or read_chunk() methods, as
+ * appropriate.
  *
  * DO NOT MIX THESE MODES. Use different 'struct chunkfile' instances
  * for reading and writing.
@@ -54,6 +55,16 @@ int pair_chunk(struct chunkfile *cf,
 	       const unsigned char **p,
 	       size_t *size);
 
+/*
+ * Similar to 'pair_chunk', but used for callers who are reading a chunk
+ * with a known number of fixed-width records.
+ */
+int pair_chunk_expect(struct chunkfile *cf,
+		      uint32_t chunk_id,
+		      const unsigned char **p,
+		      size_t record_size,
+		      size_t record_nr);
+
 typedef int (*chunk_read_fn)(const unsigned char *chunk_start,
 			     size_t chunk_size, void *data);
 /*