[svn-r5519] Purpose:

Bug Fix

Description:
    The "dirty" flag for symbol table entries and symbol table nodes was not
    being cleared when they were flushed to the file, causing lots of extra
    metadata I/O.

Solution:
    Reset the symbol table entry & nodes' flags when thy are flushed to disk.

    This reduces the number of I/O operations which hit the disk for my test
    program from 83 to 53 (i.e. from 393 to 53, overall).

Platforms tested:
    Solaris 2.7 (arabica) w/FORTRAN & FreeBSD 4.5 (sleipnir) w/C++

release_docs/RELEASE.txt

@@ -36,6 +36,8 @@ Bug Fixes since HDF5-1.4.0
 Library
 -------
 
+    * Clear symbol table node "dirty" flag when flushing symbol tables to
+      disk, to reduce I/O calls made & improve performance.  QAK - 2002/06/03
     * Fixed bug where an object's header could get corrupted in certain obscure
       situations where many objects were created in the file.  QAK - 2002/05/31
     * Fixed bug where read/write intent in file IDs created with H5Freopen

src/H5Gnode.c

@@ -338,7 +338,13 @@ H5G_node_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5G_node_t *sym)
      * Look for dirty entries and set the node dirty flag.
      */
     for (i=0; i<sym->nsyms; i++) {
-	if (sym->entry[i].dirty) sym->dirty = TRUE;
+	if (sym->entry[i].dirty) {
+            /* Set the node's dirty flag */
+            sym->dirty = TRUE;
+
+            /* Reset the entry's dirty flag */
+            sym->entry[i].dirty=FALSE;
+        } /* end if */
     }
 
     /*
@@ -376,7 +382,11 @@ H5G_node_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5G_node_t *sym)
                   "unable to write symbol table node to the file");
         if (buf)
             H5FL_BLK_FREE(symbol_node,buf);
+
+        /* Reset the node's dirty flag */
+        sym->dirty = FALSE;
     }
+
     /*
      * Destroy the symbol node?	 This might happen if the node is being
      * preempted from the cache.