Make some changes to conserve filespace and ensure that all filespace is

eventually reclaimed.

Defer reclamation of raw data filespace, only.

XXX Deferring only raw-data reclamation isn't *quite* sufficient because
XXX a writer could conceivably reuse metadata space as raw-data space
XXX before max_lag ticks have elapsed.  Readers could see metadata
XXX corrupted by raw data.

Once a file starts to close, stop deferring reclamation.

In H5MF_free_aggrs(), perform all deferred reclamations if the file is
closing.

2 files changed, 8 insertions, 2 deletions

diff --git a/src/H5MF.c b/src/H5MF.c
index a3b5765..99263b9 100644
--- a/src/H5MF.c
+++ b/src/H5MF.c
@@ -1200,8 +1200,11 @@ H5MF_xfree(H5F_t *f, H5FD_mem_t alloc_type, haddr_t addr, hsize_t size)
         HGOTO_DONE(SUCCEED)
     HDassert(addr != 0);        /* Can't deallocate the superblock :-) */
 
-    if (!f->shared->vfd_swmr_writer) {
-        // not a VFD SWMR writer, do not defer or process deferrals
+    if (!f->shared->vfd_swmr_writer || f->shared->closing ||
+        alloc_type != H5FD_MEM_DRAW) {
+        /* VFD SWMR writers defer raw-data allocations until the
+         * file starts to close.
+         */
         ret_value = H5MF__xfree_impl(f, alloc_type, addr, size);
     } else if (defer_free(f->shared, alloc_type, addr, size) < 0)
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "could not defer")
diff --git a/src/H5MFaggr.c b/src/H5MFaggr.c
index d716ae2..919ba63 100644
--- a/src/H5MFaggr.c
+++ b/src/H5MFaggr.c
@@ -753,6 +753,9 @@ H5MF_free_aggrs(H5F_t *f)
     HDassert(f->shared);
     HDassert(f->shared->lf);
 
+    if (f->shared->closing && H5MF_process_deferred_frees(f, UINT64_MAX) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "could not process deferrals")
+
     /* Retrieve metadata aggregator info, if available */
     if(H5MF__aggr_query(f, &(f->shared->meta_aggr), &ma_addr, &ma_size) < 0)
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query metadata aggregator stats")