diff --git a/doc/dev/rbd-diff.rst b/doc/dev/rbd-diff.rst
index 77a9a35d4c6..e258afd100b 100644
--- a/doc/dev/rbd-diff.rst
+++ b/doc/dev/rbd-diff.rst
@@ -5,15 +5,19 @@ This is a simple streaming file format for representing a diff between
 two snapshots (or a snapshot and the head) of an RBD image.
 
 Header
-------
+~~~~~~
 
 "rbd diff v1\n"
 
-Record
-------
+Metadata records
+~~~~~~~~~~~~~~~~
 
-Every record has a one byte "tag" that identifies the record type, followed by some other
-data.
+Every record has a one byte "tag" that identifies the record type,
+followed by some other data.
+
+Metadata records come in the first part of the image.  Order is not
+important, as long as all the metadata records come before the data
+records.
 
 From snap
 ---------
@@ -35,6 +39,11 @@ Size
 u8: 's'
 u64: (ending) image size
 
+Data Records
+~~~~~~~~~~~~
+
+These records come in the second part of the sequence.
+
 Updated data
 ------------
 
@@ -50,6 +59,10 @@ u8: 'z'
 le64: offset
 le64: length
 
+
+Final Record
+~~~~~~~~~~~~
+
 End
 ---
 
diff --git a/src/librbd/internal.h b/src/librbd/internal.h
index e0ea13ba496..7f66006e12c 100644
--- a/src/librbd/internal.h
+++ b/src/librbd/internal.h
@@ -102,7 +102,7 @@ namespace librbd {
   int resize_helper(ImageCtx *ictx, uint64_t size, ProgressContext& prog_ctx);
   int snap_create(ImageCtx *ictx, const char *snap_name);
   int snap_list(ImageCtx *ictx, std::vector<snap_info_t>& snaps);
-  bool snap_list(ImageCtx *ictx, const char *snap_name);
+  bool snap_exists(ImageCtx *ictx, const char *snap_name);
   int snap_rollback(ImageCtx *ictx, const char *snap_name,
 		    ProgressContext& prog_ctx);
   int snap_remove(ImageCtx *ictx, const char *snap_name);