From f5ca9237a296f6deefb633b6fb1d61daea4b4f6e Mon Sep 17 00:00:00 2001
From: jhendersonHDF <jhenderson@hdfgroup.org>
Date: Tue, 27 Jun 2023 23:36:12 -0500
Subject: Fix assertion failure when attempting to use IOC VFD directly (#3187)

---
 release_docs/RELEASE.txt    | 11 +++++++++++
 src/H5FDsubfiling/H5FDioc.c | 13 +++++++++++++
 testpar/CMakeTests.cmake    |  1 +
 testpar/t_subfiling_vfd.c   | 41 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 66 insertions(+)

diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index f87631a..225b17e 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -249,6 +249,17 @@ Bug Fixes since HDF5-1.14.0 release
 ===================================
     Library
     -------
+    - Fixed an assertion failure when attempting to use the Subfiling IOC
+      VFD directly
+
+      The Subfiling feature makes use of two Virtual File Drivers, the
+      Subfiling VFD and the IOC (I/O Concentrator) VFD. The two VFDs are
+      intended to be stacked together such that the Subfiling VFD sits
+      "on top" of the IOC VFD and routes I/O requests through it; using the
+      IOC VFD alone is currently unsupported. The IOC VFD has been fixed so
+      that an error message is displayed in this situation rather than causing
+      an assertion failure.
+
     - Fixed a potential bug when copying empty enum datatypes
 
       Copying an empty enum datatype (including implicitly, as when an enum
diff --git a/src/H5FDsubfiling/H5FDioc.c b/src/H5FDsubfiling/H5FDioc.c
index c9fc920..d403e3c 100644
--- a/src/H5FDsubfiling/H5FDioc.c
+++ b/src/H5FDsubfiling/H5FDioc.c
@@ -819,6 +819,19 @@ H5FD__ioc_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr)
     /* Retrieve the HDF5 stub file ID for the current file */
     if (H5_subfiling_get_file_id_prop(plist_ptr, &file_ptr->file_id) < 0)
         H5_SUBFILING_GOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get stub file ID from FAPL");
+    if (file_ptr->file_id == UINT64_MAX) {
+        /* Since this VFD does no displaying of error stacks itself
+         * (it relies on the Subfiling VFD to do this), we must print
+         * the error stack here if we know it wasn't stacked under the
+         * Subfiling VFD.
+         */
+        H5_SUBFILING_DONE_ERROR(
+            H5E_PLIST, H5E_BADVALUE, NULL,
+            "subfiling stub file ID property was missing from FAPL - IOC VFD wasn't correctly stacked under "
+            "the Subfiling VFD and cannot currently be used alone");
+        PRINT_ERROR_STACK;
+        goto done;
+    }
 
     /*
      * Open the subfiles for this HDF5 file. A subfiling
diff --git a/testpar/CMakeTests.cmake b/testpar/CMakeTests.cmake
index a77535c..dfdde59 100644
--- a/testpar/CMakeTests.cmake
+++ b/testpar/CMakeTests.cmake
@@ -99,6 +99,7 @@ set (test_par_CLEANFILES
     MPItest.h5
     ShapeSameTest.h5
     test_subfiling_basic_create.h5
+    test_subfiling_only_ioc_fail.h5
     test_subfiling_config_file.h5
     test_subfiling_stripe_sizes.h5
     test_subfiling_selection_strategies.h5
diff --git a/testpar/t_subfiling_vfd.c b/testpar/t_subfiling_vfd.c
index 10a4dd2..04d8762 100644
--- a/testpar/t_subfiling_vfd.c
+++ b/testpar/t_subfiling_vfd.c
@@ -91,6 +91,7 @@ static hid_t create_subfiling_ioc_fapl(MPI_Comm comm, MPI_Info info, hbool_t cus
 
 /* Test functions */
 static void test_create_and_close(void);
+static void test_ioc_only_fail(void);
 static void test_config_file(void);
 static void test_stripe_sizes(void);
 static void test_selection_strategies(void);
@@ -102,6 +103,7 @@ static void test_subfiling_h5fuse(void);
 
 static test_func tests[] = {
     test_create_and_close,
+    test_ioc_only_fail,
     test_config_file,
     test_stripe_sizes,
     test_selection_strategies,
@@ -219,6 +221,45 @@ test_create_and_close(void)
 #undef SUBF_FILENAME
 
 /*
+ * A simple test that ensures file creation fails when
+ * attempting to use the IOC VFD by itself, without it
+ * being stacked under the Subfiling VFD. This is
+ * currently unsupported.
+ */
+#define SUBF_FILENAME "test_subfiling_only_ioc_fail.h5"
+static void
+test_ioc_only_fail(void)
+{
+    hid_t file_id = H5I_INVALID_HID;
+    hid_t fapl_id = H5I_INVALID_HID;
+
+    curr_nerrors = nerrors;
+
+    if (MAINPROCESS)
+        TESTING_2("invalid use of IOC VFD by itself");
+
+    /* Setup a FAPL using only the IOC VFD */
+    fapl_id = H5Pcreate(H5P_FILE_ACCESS);
+    VRFY((fapl_id >= 0), "H5Pcreate succeeded");
+
+    VRFY((H5Pset_mpi_params(fapl_id, comm_g, info_g) >= 0), "H5Pset_mpi_params succeeded");
+
+    VRFY((H5Pset_fapl_ioc(fapl_id, NULL) >= 0), "H5Pset_fapl_ioc succeeded");
+
+    H5E_BEGIN_TRY
+    {
+        file_id = H5Fcreate(SUBF_FILENAME, H5F_ACC_TRUNC, H5P_DEFAULT, fapl_id);
+    }
+    H5E_END_TRY;
+    VRFY((file_id < 0), "H5Fcreate failed successfully");
+
+    VRFY((H5Pclose(fapl_id) >= 0), "FAPL close succeeded");
+
+    CHECK_PASSED();
+}
+#undef SUBF_FILENAME
+
+/*
  * Test to check that Subfiling configuration file matches
  * what is expected for a given configuration
  */
-- 
cgit v0.12