Bug Fix: open files that use Lustre Progressive File Layout (PFL)

configure.ac

@@ -2937,6 +2937,7 @@ AC_CONFIG_FILES(Makefile \
                 test/F90/Makefile \
                 test/burst_buffer/Makefile \
                 test/cdl/Makefile \
+                test/Lustre/Makefile \
 )
 
 dnl The following dependency is for configure.in and configure

sneak_peek.md

@@ -62,6 +62,10 @@ This is essentially a placeholder for the next release note ...
     See [PR #230](https://github.com/Parallel-NetCDF/PnetCDF/pull/230).
 
 * Bug fixes
+  + Fix a divide-by-zero error when opening a file that is striped using the
+    Lustre Progressive File Layout (PFL). The bug was reported in
+    [Issue #234](https://github.com/Parallel-NetCDF/PnetCDF/issues/234).
+    See fix in [PR #236](https://github.com/Parallel-NetCDF/PnetCDF/pull/236).
   + Fix detection of the MPI base compiler names when PrgEnv-cray is loaded,
     where cc, CC, and ftn are wrappers of Cray clang and Cray Fortran
     compilers.

test/Lustre/Makefile.am

@@ -0,0 +1,57 @@
+#
+# Copyright (C) 2026, Northwestern University and Argonne National Laboratory
+# See COPYRIGHT notice in top-level directory.
+#
+# @configure_input@
+
+SUFFIXES = .o .c
+
+AM_DEFAULT_SOURCE_EXT = .c
+
+AM_CPPFLAGS =
+
+LDADD =
+
+if DECL_MPI_OFFSET
+   AM_CPPFLAGS += -DHAVE_DECL_MPI_OFFSET
+endif
+
+check_PROGRAMS =
+
+# autimake 1.11.3 has not yet implemented AM_TESTS_ENVIRONMENT
+# For newer versions, we can use AM_TESTS_ENVIRONMENT instead
+TESTS_ENVIRONMENT  = export SED="$(SED)";
+TESTS_ENVIRONMENT += export srcdir="$(srcdir)";
+TESTS_ENVIRONMENT += export top_builddir="$(top_builddir)";
+TESTS_ENVIRONMENT += export TESTOUTDIR="$(FSTYPE_PREFIX)$(TESTOUTDIR)";
+TESTS_ENVIRONMENT += export TESTSEQRUN="$(TESTSEQRUN)";
+TESTS_ENVIRONMENT += export TESTMPIRUN="$(TESTMPIRUN)";
+TESTS_ENVIRONMENT += export check_PROGRAMS="$(check_PROGRAMS)";
+
+TESTS_ENVIRONMENT += export ENABLE_BURST_BUFFER=@ENABLE_BURST_BUFFER@;
+TESTS_ENVIRONMENT += export ENABLE_NETCDF4=@ENABLE_NETCDF4@;
+TESTS_ENVIRONMENT += export ENABLE_THREAD_SAFE=@ENABLE_THREAD_SAFE@;
+TESTS_ENVIRONMENT += export MIMIC_LUSTRE=@MIMIC_LUSTRE@;
+
+# build check targets but not invoke by not setting TESTS
+# TESTS = $(check_PROGRAMS)
+TEST_EXTENSIONS = .sh
+LOG_COMPILER = $(srcdir)/seq_runs.sh
+SH_LOG_COMPILER =
+
+check_SCRIPTS = seq_runs.sh parallel_run.sh
+
+EXTRA_DIST = seq_runs.sh parallel_run.sh
+
+CLEANFILES = core core.* *.gcda *.gcno *.gcov gmon.out
+
+../common/libtestutils.la:
+	set -e; cd ../common && $(MAKE) $(MFLAGS) tests
+
+ptest2 ptest4 ptest6 ptest8 ptest10:
+
+# build check targets but not invoke
+tests-local: all $(check_PROGRAMS)
+
+.PHONY: ptest ptests ptest2 ptest4 ptest6 ptest8 ptest10
+

test/Lustre/parallel_run.sh

@@ -0,0 +1,50 @@
+#!/bin/bash
+#
+# Copyright (C) 2026, Northwestern University and Argonne National Laboratory
+# See COPYRIGHT notice in top-level directory.
+#
+
+# Exit immediately if a command exits with a non-zero status.
+set -e
+
+DRY_RUN=no
+VERBOSE=no
+
+run_cmd() {
+   local lineno=${BASH_LINENO[$((${#BASH_LINENO[@]} - 2))]}
+   if test "x$VERBOSE" = xyes || test "x$DRY_RUN" = xyes ; then
+      echo "Line $lineno CMD: $MPIRUN $@"
+   fi
+   if test "x$DRY_RUN" = xno ; then
+      $MPIRUN $@
+   fi
+}
+
+MPIRUN=`echo ${TESTMPIRUN} | ${SED} -e "s/NP/$1/g"`
+# echo "MPIRUN = ${MPIRUN}"
+# echo "check_PROGRAMS=${check_PROGRAMS}"
+
+# prevent user environment setting of PNETCDF_HINTS to interfere
+unset PNETCDF_HINTS
+
+if test "x$MIMIC_LUSTRE" != x1 ; then
+   PNETCDF_HINTS="cb_nodes=2"
+fi
+
+for i in ${check_PROGRAMS} ; do
+
+   # SECONDS=0
+   # start_ns=$(date +%s.%4N)
+
+   exe_name=`basename $i`
+
+   run_cmd ./$i -q -o ${TESTOUTDIR}/${exe_name}.nc
+
+   # # echo "Elapsed: $SECONDS seconds"
+   # end_ns=$(date +%s.%4N)
+   # # Calculate difference (requires bc for floating point math)
+   # elapsed_ns=$(echo "$end_ns - $start_ns" | bc)
+   # echo "Elapsed time: ${elapsed_ns} seconds"
+
+done # check_PROGRAMS
+

test/Lustre/seq_runs.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+#
+# Copyright (C) 2026, Northwestern University and Argonne National Laboratory
+# See COPYRIGHT notice in top-level directory.
+#
+
+# Exit immediately if a command exits with a non-zero status.
+set -e
+
+DRY_RUN=no
+VERBOSE=no
+
+run_cmd() {
+   local lineno=${BASH_LINENO[$((${#BASH_LINENO[@]} - 2))]}
+   if test "x$VERBOSE" = xyes || test "x$DRY_RUN" = xyes ; then
+      echo "Line $lineno CMD: $TESTSEQRUN $@"
+   fi
+   if test "x$DRY_RUN" = xno ; then
+      $TESTSEQRUN $@
+   fi
+}
+
+exe_name=`basename $1`
+
+# prevent user environment setting of PNETCDF_HINTS to interfere
+unset PNETCDF_HINTS
+
+run_cmd ./$1 -q -o ${TESTOUTDIR}/${exe_name}.nc
+