Omnibus checkin for several relatively minor modifications:

1) Added code test/page_buffer.c to verify that page buffering is
   disabled in parallel builds.

2) Added code to test/cache_image.c to verify correct interaction
   between evict on close and cache image -- in particular management
   of a file containing a cache image containing dirty metadata that
   has been opened R/O.  Also fix for the bug exposed.

3) Added code to testpar/t_cache_image.c to verify expected procedure
   for reading cache images, and also supporting stats collection code
   needed for the test.

4) Repair of an overactive sanity check in H5C__reconstruct_cache_contents().

5) Other minor tidies in passing.

Tested serial and parallel, debug and production on Jelly.

1 files changed, 21 insertions, 0 deletions

diff --git a/src/H5Cpkg.h b/src/H5Cpkg.h
index 69e8145..90a84c4 100644
--- a/src/H5Cpkg.h
+++ b/src/H5Cpkg.h
@@ -686,6 +686,13 @@ if ( ( ( ( (head_ptr) == NULL ) || ( (tail_ptr) == NULL ) ) &&             \
     (cache_ptr)->images_created++;                          \
 }
 
+#define H5C__UPDATE_STATS_FOR_CACHE_IMAGE_READ(cache_ptr)  \
+{                                                          \
+    /* make sure image len is still good */                \
+    HDassert((cache_ptr)->image_len > 0);                  \
+    (cache_ptr)->images_read++;                            \
+}
+
 #define H5C__UPDATE_STATS_FOR_CACHE_IMAGE_LOAD(cache_ptr)  \
 {                                                          \
     /* make sure image len is still good */                \
@@ -931,6 +938,7 @@ if ( ( ( ( (head_ptr) == NULL ) || ( (tail_ptr) == NULL ) ) &&             \
 #define H5C__UPDATE_STATS_FOR_LRU_SCAN_RESTART(cache_ptr)
 #define H5C__UPDATE_STATS_FOR_INDEX_SCAN_RESTART(cache_ptr)
 #define H5C__UPDATE_STATS_FOR_CACHE_IMAGE_CREATE(cache_ptr)
+#define H5C__UPDATE_STATS_FOR_CACHE_IMAGE_READ(cache_ptr)
 #define H5C__UPDATE_STATS_FOR_CACHE_IMAGE_LOAD(cache_ptr)
 #define H5C__UPDATE_STATS_FOR_PREFETCH(cache_ptr, dirty)
 #define H5C__UPDATE_STATS_FOR_PREFETCH_HIT(cache_ptr)
@@ -4549,6 +4557,18 @@ typedef struct H5C_tag_info_t {
  *		Further, since cache images are only created at file 
  *		close, this field should only be set at that time.
  *
+ * images_read: Integer field containing the number of cache images 
+ *              read from file.  Note that reading an image is different
+ *              from loading it -- reading the image means just that,
+ *              while loading the image refers to decoding it and loading
+ *              it into the metadata cache.
+ *
+ *              In the serial case, image_read should always equal 
+ *              images_loaded.  However, in the parallel case, the 
+ *              image should only be read by process 0.  All other 
+ *              processes should receive the cache image via a broadcast
+ *              from process 0.
+ *
  * images_loaded:  Integer field containing the number of cache images
  *		loaded since the last time statistics were reset.
  *
@@ -4864,6 +4884,7 @@ struct H5C_t {
 
     /* Fields for tracking cache image operations */
     int32_t			images_created;
+    int32_t			images_read;
     int32_t			images_loaded;
     hsize_t			last_image_size;