Merge in reentrency changes to "make space in cache" from page_buffering branch.

2 files changed, 38 insertions, 0 deletions

diff --git a/src/H5C.c b/src/H5C.c
index 0eb9d9b..1759292 100644
--- a/src/H5C.c
+++ b/src/H5C.c
@@ -386,6 +386,7 @@ H5C_create(size_t		      max_cache_size,
     cache_ptr->cache_full			= FALSE;
     cache_ptr->size_decreased			= FALSE;
     cache_ptr->resize_in_progress		= FALSE;
+    cache_ptr->msic_in_progress			= FALSE;
 
     (cache_ptr->resize_ctl).version		= H5C__CURR_AUTO_SIZE_CTL_VER;
     (cache_ptr->resize_ctl).rpt_fcn		= NULL;
@@ -6904,6 +6905,7 @@ H5C__make_space_in_cache(H5F_t *f, hid_t dxpl_id, size_t space_needed,
     uint32_t		entries_examined = 0;
     uint32_t		initial_list_len;
     size_t		empty_space;
+    hbool_t             reentrant_call = FALSE;
     hbool_t		prev_is_dirty = FALSE;
     hbool_t             didnt_flush_entry = FALSE;
     hbool_t		restart_scan;
@@ -6921,6 +6923,18 @@ H5C__make_space_in_cache(H5F_t *f, hid_t dxpl_id, size_t space_needed,
     HDassert(cache_ptr->magic == H5C__H5C_T_MAGIC);
     HDassert(cache_ptr->index_size == (cache_ptr->clean_index_size + cache_ptr->dirty_index_size));
 
+    /* check to see if cache_ptr->msic_in_progress is TRUE.  If it, this
+     * is a re-entrant call via a client callback called in the make 
+     * space in cache process.  To avoid an infinite recursion, set 
+     * reentrant_call to TRUE, and goto done.
+     */
+    if(cache_ptr->msic_in_progress) {
+        reentrant_call = TRUE;
+        HGOTO_DONE(SUCCEED);
+    } /* end if */
+
+    cache_ptr->msic_in_progress = TRUE;
+
     if ( write_permitted ) {
         restart_scan = FALSE;
         initial_list_len = cache_ptr->LRU_list_len;
@@ -7180,6 +7194,12 @@ H5C__make_space_in_cache(H5F_t *f, hid_t dxpl_id, size_t space_needed,
     }
 
 done:
+    /* Sanity checks */
+    HDassert(cache_ptr->msic_in_progress);
+    if(!reentrant_call)
+        cache_ptr->msic_in_progress = FALSE;
+    HDassert((!reentrant_call) || (cache_ptr->msic_in_progress));
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5C__make_space_in_cache() */
 
diff --git a/src/H5Cpkg.h b/src/H5Cpkg.h
index 3ea5144..321f1fb 100644
--- a/src/H5Cpkg.h
+++ b/src/H5Cpkg.h
@@ -4104,6 +4104,23 @@ typedef struct H5C_tag_info_t {
  *		of changes to the file driver info superblock extension
  *		management code needed to support rings.
  *
+ * msic_in_progress: As the metadata cache has become re-entrant, and as
+ *              the free space manager code has become more tightly 
+ *              integrated with the metadata cache, it is possible that 
+ *              a call to H5C_insert_entry() may trigger a call to 
+ *              H5C_make_space_in_cache(), which, via H5C__flush_single_entry()
+ *              and client callbacks, may trigger an infinite regression
+ *              of calls to H5C_make_space_in_cache().
+ *
+ *              The msic_in_progress boolean flag is used to detect this,
+ *              and prevent the infinite regression that would otherwise
+ *              occur.
+ *
+ *              Note that this is issue is not hypothetical -- this field 
+ *              was added 2/16/17 to address this issue when it was 
+ *              exposed by modifications to test/fheap.c to cause it to 
+ *              use paged allocation.
+ *
  * resize_ctl:	Instance of H5C_auto_size_ctl_t containing configuration
  * 		data for automatic cache resizing.
  *
@@ -4743,6 +4760,7 @@ struct H5C_t {
     hbool_t			cache_full;
     hbool_t			size_decreased;
     hbool_t			resize_in_progress;
+    hbool_t			msic_in_progress;
     H5C_auto_size_ctl_t		resize_ctl;
 
     /* Fields for epoch markers used in automatic cache size adjustment */