Merge remote-tracking branch 'origin/develop' into threading_updates

doxygen/dox/IntroParHDF5.dox

@@ -23,8 +23,13 @@ Implementation requirements were to:
 \li Not have a reserved process, as this might interfere with parallel algorithms.
 \li Not spawn any processes, as this is not even commonly supported now.
 
-The following shows the Parallel HDF5 implementation layers.
+The following shows the Parallel HDF5 implementation layers:
 
+<table>
+<tr><td>
+\image html pimplayer.gif
+</td></tr>
+</table>
 
 \subsection subsec_pintro_prog Parallel Programming with HDF5
 This tutorial assumes that you are somewhat familiar with parallel programming with MPI (Message Passing Interface).

src/H5Fpkg.h

@@ -131,6 +131,10 @@
     (H5F_SUPERBLOCK_FIXED_SIZE +                                                                             \
      H5F_SUPERBLOCK_VARLEN_SIZE((s)->super_vers, (s)->sizeof_addr, (s)->sizeof_size))
 
+/* Optimistic read size for superblock */
+/* Size of a v2+ superblock, w/8-byte addresses & lengths */
+#define H5F_SUPERBLOCK_SPEC_READ_SIZE (H5F_SUPERBLOCK_FIXED_SIZE + H5F_SUPERBLOCK_VARLEN_SIZE(2, 8, 8))
+
 /* For superblock version 0 & 1:
    Offset to the file consistency flags (status_flags) in the superblock (excluding H5F_SUPERBLOCK_FIXED_SIZE)
  */

src/H5Fsuper.c

@@ -416,8 +416,7 @@ H5F__super_read(H5F_t *f, H5P_genplist_t *fa_plist, bool initial_read)
         HGOTO_ERROR(H5E_FILE, H5E_BADTYPE, FAIL, "can't get property list");
 
     /* Make certain we can read the fixed-size portion of the superblock */
-    if (H5F__set_eoa(f, H5FD_MEM_SUPER,
-                     (haddr_t)(H5F_SUPERBLOCK_FIXED_SIZE + H5F_SUPERBLOCK_MINIMAL_VARLEN_SIZE)) < 0)
+    if (H5F__set_eoa(f, H5FD_MEM_SUPER, (haddr_t)H5F_SUPERBLOCK_SPEC_READ_SIZE) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "set end of space allocation request failed");
 
     /* Set up the user data for cache callbacks */
@@ -583,13 +582,10 @@ H5F__super_read(H5F_t *f, H5P_genplist_t *fa_plist, bool initial_read)
 
     if (H5F_INTENT(f) & H5F_ACC_SWMR_READ) {
         /*
-         * When the file is opened for SWMR read access, skip the check if:
-         * --the file is already marked for SWMR writing and
-         * --the file has version 3 superblock for SWMR support
+         * When the file is opened for SWMR read access, skip the check if
+         * the file has a version 3 superblock capable of SWMR support
          */
-        if ((sblock->status_flags & H5F_SUPER_SWMR_WRITE_ACCESS) &&
-            (sblock->status_flags & H5F_SUPER_WRITE_ACCESS) &&
-            sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_3)
+        if (sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_3)
             skip_eof_check = true;
     }
     if (!skip_eof_check && initial_read) {

src/H5Fsuper_cache.c

@@ -306,8 +306,7 @@ H5F__cache_superblock_get_initial_load_size(void H5_ATTR_UNUSED *_udata, size_t
     assert(image_len);
 
     /* Set the initial image length size */
-    *image_len = H5F_SUPERBLOCK_FIXED_SIZE + /* Fixed size of superblock */
-                 H5F_SUPERBLOCK_MINIMAL_VARLEN_SIZE;
+    *image_len = H5F_SUPERBLOCK_SPEC_READ_SIZE;
 
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* end H5F__cache_superblock_get_initial_load_size() */