Merge pull request #207 in HDFFV/hdf5 from ~KOZIOL/hdf5:develop_swmr_merge_06 to develop

* commit 'f8cfbee05e26a815134cd1f1fb0ad87d8d9b16dd':
  Merge SWMR-related testing to existing tests.
  Bring over tweak for missing environment variable.
  Update CMake configuration files with SWMR accumulator changes.
  Add missing accumulator test.
  Merge SWMR-oriented accumulator tests from revise_chunks to develop.

13 files changed, 743 insertions, 61 deletions

diff --git a/MANIFEST b/MANIFEST
index 1f26d95..3141519 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -884,6 +884,7 @@
 ./test/H5srcdir_str.h.in
 ./test/Makefile.am
 ./test/accum.c
+./test/accum_swmr_reader.c
 ./test/app_ref.c
 ./test/bad_compound.h5
 ./test/be_data.h5
diff --git a/src/H5Ocache.c b/src/H5Ocache.c
index 94498ee..d398e41 100644
--- a/src/H5Ocache.c
+++ b/src/H5Ocache.c
@@ -46,12 +46,6 @@
 /* Local Macros */
 /****************/
 
-/* Set the object header size to speculatively read in */
-/* (needs to be more than the object header prefix size to work at all and
- *      should be larger than the largest object type's default object header
- *      size to save the extra I/O operations) */
-#define H5O_SPEC_READ_SIZE 512
-
 
 /******************/
 /* Local Typedefs */
diff --git a/src/H5Opkg.h b/src/H5Opkg.h
index e778f90..ef49535 100644
--- a/src/H5Opkg.h
+++ b/src/H5Opkg.h
@@ -217,6 +217,12 @@
 #define H5O_SHARE_IS_SHARABLE   0x01
 #define H5O_SHARE_IN_OHDR       0x02
 
+/* Set the object header size to speculatively read in */
+/* (needs to be more than the object header prefix size to work at all and
+ *      should be larger than the largest object type's default object header
+ *      size to save the extra I/O operations) */
+#define H5O_SPEC_READ_SIZE 512
+
 
 /* The "message class" type */
 struct H5O_msg_class_t {
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 5a55616..0197524 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -196,7 +196,6 @@ MACRO (ADD_H5_EXE file)
 ENDMACRO (ADD_H5_EXE file)
 
 set (H5_TESTS
-    #testhdf5
     cache
     cache_api
     cache_tagging
@@ -211,7 +210,6 @@ set (H5_TESTS
     fheap
     pool
     accum
-    #hyperslab
     istore
     bittests
     dt_arith
@@ -234,7 +232,6 @@ set (H5_TESTS
     app_ref
     enum
     set_extent
-    #ttsafe
     enc_dec_plist
     enc_dec_plist_cross_platform
     getname
@@ -328,6 +325,21 @@ foreach (test ${H5_CHECK_TESTS})
   ADD_H5_EXE(${test})
 endforeach (test ${H5_CHECK_TESTS})
 
+#-- Adding test for accum_swmr_reader
+#   This has to be copied to the test directory for execve() to find it
+#   and it can't be renamed (i.e., no <foo>-shared).
+add_executable (accum_swmr_reader ${HDF5_TEST_SOURCE_DIR}/accum_swmr_reader.c)
+TARGET_NAMING (accum_swmr_reader STATIC)
+TARGET_C_PROPERTIES (accum_swmr_reader STATIC " " " ")
+target_link_libraries (accum_swmr_reader ${HDF5_LIB_TARGET} ${HDF5_TEST_LIB_TARGET})
+set_target_properties (accum_swmr_reader PROPERTIES FOLDER test)
+
+#-- Set accum dependencies
+set_target_properties (accum PROPERTIES DEPENDS accum_swmr_reader)
+if (BUILD_SHARED_LIBS)
+  set_target_properties (accum-shared PROPERTIES DEPENDS accum_swmr_reader)
+endif (BUILD_SHARED_LIBS)
+
 #-- Adding test for libinfo
 set (GREP_RUNNER ${PROJECT_BINARY_DIR}/GrepRunner.cmake)
 file (WRITE ${GREP_RUNNER}
diff --git a/test/CMakeTests.cmake b/test/CMakeTests.cmake
index 3fc0fb6..0ccb557 100644
--- a/test/CMakeTests.cmake
+++ b/test/CMakeTests.cmake
@@ -43,6 +43,21 @@ set (HDF5_TEST_FILES
   tnullspace.h5
 )
 
+add_custom_command (
+    TARGET     accum_swmr_reader
+    POST_BUILD
+    COMMAND    ${CMAKE_COMMAND}
+    ARGS       -E copy_if_different "$<TARGET_FILE:accum_swmr_reader>" "${PROJECT_BINARY_DIR}/H5TEST/accum_swmr_reader"
+)
+if (BUILD_SHARED_LIBS)
+  add_custom_command (
+      TARGET     accum_swmr_reader
+      POST_BUILD
+      COMMAND    ${CMAKE_COMMAND}
+      ARGS       -E copy_if_different "$<TARGET_FILE:accum_swmr_reader>" "${PROJECT_BINARY_DIR}/H5TEST-shared/accum_swmr_reader"
+  )
+endif (BUILD_SHARED_LIBS)
+
 foreach (h5_tfile ${HDF5_TEST_FILES})
   HDFTEST_COPY_FILE("${HDF5_TOOLS_DIR}/testfiles/${h5_tfile}" "${PROJECT_BINARY_DIR}/H5TEST/${h5_tfile}" "HDF5_TEST_LIB_files")
   if (BUILD_SHARED_LIBS)
@@ -493,6 +508,8 @@ set (test_CLEANFILES
     vds_src_0.h5
     vds_src_1.h5
     tbogus.h5.copy
+    accum_swmr_big.h5
+    ohdr_swmr.h5
     cache_logging.h5
     cache_logging.out
 )
diff --git a/test/Makefile.am b/test/Makefile.am
index 380043a..5a63c89 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -53,12 +53,13 @@ TEST_PROG= testhdf5 cache cache_api cache_tagging lheap ohdr stab gheap \
 # List programs to be built when testing here.
 # error_test and err_compat are built at the same time as the other tests, but executed by testerror.sh.
 # tcheck_version is used by testcheck_version.sh.
+# accum_swmr_reader is used by accum.c.
 # links_env is used by testlinks_env.sh
 # 'make check' doesn't run them directly, so they are not included in TEST_PROG.
 # Also build testmeta, which is used for timings test.  It builds quickly,
 # and this lets automake keep all its test programs in one place.
 check_PROGRAMS=$(TEST_PROG) error_test err_compat tcheck_version \
-    testmeta \
+    testmeta accum_swmr_reader \
     links_env 
 if HAVE_SHARED_CONDITIONAL
   check_PROGRAMS+= plugin
@@ -162,6 +163,7 @@ CHECK_CLEANFILES+=accum.h5 cmpd_dset.h5 compact_dataset.h5 dataset.h5 dset_offse
     split_get_file_image_test-m.h5 split_get_file_image_test-r.h5    \
     file_image_core_test.h5.copy unregister_filter_1.h5 unregister_filter_2.h5 \
     vds_virt.h5 vds_dapl.h5 vds_src_[0-1].h5 \
+    accum_swmr_big.h5 ohdr_swmr.h5 \
     cache_logging.h5 cache_logging.out \
     swmr[0-2].h5
 # Sources for testhdf5 executable
diff --git a/test/accum.c b/test/accum.c
index 3b9f9e6..1fcd051 100644
--- a/test/accum.c
+++ b/test/accum.c
@@ -18,13 +18,20 @@
 #include "h5test.h"
 
 #define H5F_FRIEND		/*suppress error about including H5Fpkg	  */
+#define H5FD_FRIEND		/*suppress error about including H5FDpkg	  */
+#define H5FD_TESTING
 #include "H5Fpkg.h"
-#include "H5FDprivate.h"
+#include "H5FDpkg.h"
 #include "H5Iprivate.h"
 
 /* Filename */
 #define FILENAME "accum.h5"
 
+/* The file name is the same as the define in accum_swmr_reader.c */
+#define SWMR_FILENAME "accum_swmr_big.h5"
+/* The reader forked by test_swmr_write_big() */
+#define SWMR_READER "accum_swmr_reader"
+
 /* "big" I/O test values */
 #define BIG_BUF_SIZE (6 * 1024 * 1024)
 
@@ -50,6 +57,7 @@ unsigned test_read_after(const H5F_io_info_t *fio_info);
 unsigned test_free(const H5F_io_info_t *fio_info);
 unsigned test_big(const H5F_io_info_t *fio_info);
 unsigned test_random_write(const H5F_io_info_t *fio_info);
+unsigned test_swmr_write_big(hbool_t newest_format);
 
 /* Helper Function Prototypes */
 void accum_printf(void);
@@ -124,6 +132,10 @@ main(void)
     if(H5Fclose(fid) < 0) TEST_ERROR
     HDremove(FILENAME);
 
+    /* This test uses a different file */
+    nerrors += test_swmr_write_big(TRUE);
+    nerrors += test_swmr_write_big(FALSE);
+
     if(nerrors)
         goto error;
     puts("All metadata accumulator tests passed.");
@@ -1777,6 +1789,216 @@ error:
     return 1;
 } /* end test_random_write() */
 
+/*-------------------------------------------------------------------------
+ * Function:    test_swmr_write_big
+ * 
+ * Purpose:    	A SWMR test: verifies that writing "large" metadata to a file
+ *		opened with SWMR_WRITE will flush the existing metadata in the 
+ *		accumulator to disk first before writing the "large" metadata
+ *	 	to disk.  
+ *		This test will fork and exec a reader "accum_swmr_reader" which
+ *		opens the same file with SWMR_READ and verifies that the correct
+ *		metadata is read from disk.
+ * 
+ * Return:      Success: 0
+ *              Failure: 1
+ * 
+ * Programmer:  Vailin Choi; April 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+unsigned 
+test_swmr_write_big(hbool_t newest_format)
+{
+    hid_t fid = -1;			    /* File ID */
+    hid_t fapl = -1;			/* File access property list */
+    H5F_t *rf = NULL;			/* File pointer */
+    uint8_t *wbuf2 = NULL, *rbuf = NULL;      /* Buffers for reading & writing */
+    uint8_t wbuf[1024];			/* Buffer for reading & writing */
+    unsigned u;                 /* Local index variable */
+#ifdef H5_HAVE_UNISTD_H
+    pid_t pid;				    /* Process ID */
+#endif /* H5_HAVE_UNISTD_H */
+    int status;				    /* Status returned from child process */
+    H5F_io_info_t fio_info;     /* I/O info for operation */
+    char *new_argv[] = {NULL};
+    char *driver = NULL;        /* VFD string (from env variable) */
+
+    if(newest_format) {
+	    TESTING("SWMR write of large metadata: with latest format");
+    } else {
+	    TESTING("SWMR write of large metadata: with non-latest-format");
+    } /* end if */
+
+#if !(defined(H5_HAVE_FORK) && defined(H5_HAVE_WAITPID))
+
+    SKIPPED();
+    HDputs("    Test skipped due to fork or waitpid not defined.");
+    return 0;
+
+#else /* defined(H5_HAVE_FORK && defined(H5_HAVE_WAITPID) */
+
+    /* Skip this test if SWMR I/O is not supported for the VFD specified
+     * by the environment variable.
+     */
+    driver = HDgetenv("HDF5_DRIVER");
+    if (!H5FD_supports_swmr_test(driver)) {
+        SKIPPED();
+        HDputs("    Test skipped due to VFD not supporting SWMR I/O.");
+        return 0;
+    } /* end if */
+
+    /* File access property list */
+    if((fapl = h5_fileaccess()) < 0)
+        FAIL_STACK_ERROR
+
+    /* Both cases will result in v3 superblock and version 2 object header for SWMR */
+    if(newest_format) { /* latest format */
+        if(H5Pset_libver_bounds(fapl, H5F_LIBVER_LATEST, H5F_LIBVER_LATEST) < 0)
+            FAIL_STACK_ERROR
+
+	if((fid = H5Fcreate(SWMR_FILENAME, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+	    FAIL_STACK_ERROR
+    } else { /* non-latest-format */
+        if((fid = H5Fcreate(SWMR_FILENAME, H5F_ACC_TRUNC|H5F_ACC_SWMR_WRITE, H5P_DEFAULT, fapl)) < 0)
+            FAIL_STACK_ERROR
+    } /* end if */
+
+    /* Close the file */
+    if(H5Fclose(fid) < 0)
+        FAIL_STACK_ERROR
+
+    /* Open the file with SWMR_WRITE */
+    if((fid = H5Fopen(SWMR_FILENAME, H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE, fapl)) < 0)
+        FAIL_STACK_ERROR
+
+    /* Get H5F_t * to internal file structure */
+    if(NULL == (rf = (H5F_t *)H5I_object(fid))) FAIL_STACK_ERROR
+
+    /* Set up I/O info for operation */
+    fio_info.f = rf;
+    if(NULL == (fio_info.dxpl = (H5P_genplist_t *)H5I_object(H5AC_ind_read_dxpl_id)))
+        FAIL_STACK_ERROR
+
+    /* We'll be writing lots of garbage data, so extend the
+        file a ways. 10MB should do. */
+    if(H5FD_set_eoa(rf->shared->lf, H5FD_MEM_DEFAULT, (haddr_t)(1024*1024*10)) < 0)
+        FAIL_STACK_ERROR
+
+    if(H5Fflush(fid, H5F_SCOPE_GLOBAL) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Reset metadata accumulator for the file */
+    if(accum_reset(&fio_info) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Allocate space for the write & read buffers */
+    if((wbuf2 = (uint8_t *)HDmalloc((size_t)BIG_BUF_SIZE)) == NULL)
+	    FAIL_STACK_ERROR;
+    if((rbuf = (uint8_t *)HDmalloc((size_t)BIG_BUF_SIZE)) == NULL)
+	    FAIL_STACK_ERROR;
+
+    /* Initialize wbuf with "0, 1, 2...1024"*/
+    for(u = 0; u < 1024; u++)
+        wbuf[u] = (uint8_t)u;
+
+    /* Write [1024, 1024] bytes with wbuf */
+    if(H5F_block_write(rf, H5FD_MEM_DEFAULT, (haddr_t)1024, (size_t)1024, H5AC_ind_read_dxpl_id, wbuf) < 0)
+	    FAIL_STACK_ERROR;
+    /* Read the data */
+    if(H5F_block_read(rf, H5FD_MEM_DEFAULT, (haddr_t)1024, (size_t)1024, H5AC_ind_read_dxpl_id, rbuf) < 0)
+	    FAIL_STACK_ERROR;
+    /* Verify the data read is correct */
+    if(HDmemcmp(wbuf, rbuf, (size_t)1024) != 0)
+        TEST_ERROR;
+    /* Flush the data to disk */
+    if(accum_reset(&fio_info) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Initialize wbuf with all 1s */
+    for(u = 0; u < 1024; u++)
+        wbuf[u] = (uint8_t)1;
+
+    /* Initialize wbuf2 */
+    for(u = 0; u < BIG_BUF_SIZE; u++)
+        wbuf2[u] = (uint8_t)(u + 1);
+
+    /* Write [1024,1024] with wbuf--all 1s */
+    if(H5F_block_write(rf, H5FD_MEM_DEFAULT, (haddr_t)1024, (size_t)1024, H5AC_ind_read_dxpl_id, wbuf) < 0)
+	    FAIL_STACK_ERROR;
+    /* Read the data */
+    if(H5F_block_read(rf, H5FD_MEM_DEFAULT, (haddr_t)1024, (size_t)1024, H5AC_ind_read_dxpl_id, rbuf) < 0)
+	    FAIL_STACK_ERROR;
+    /* Verify the data read is correct */
+    if(HDmemcmp(wbuf, rbuf, (size_t)1024) != 0)
+        TEST_ERROR;
+    /* The data stays in the accumulator */
+
+    /* Write a large piece of metadata [2048, BIG_BUF_SIZE] with wbuf2 */
+    if(H5F_block_write(rf, H5FD_MEM_DEFAULT, (haddr_t)2048, (size_t)BIG_BUF_SIZE, H5AC_ind_read_dxpl_id, wbuf2) < 0)
+	    FAIL_STACK_ERROR;
+    /* Read the data */
+    if(H5F_block_read(rf, H5FD_MEM_DEFAULT, (haddr_t)2048, (size_t)BIG_BUF_SIZE, H5AC_ind_read_dxpl_id, rbuf) < 0)
+	    FAIL_STACK_ERROR;
+    /* Verify the data read is correct */
+    if(HDmemcmp(wbuf2, rbuf, (size_t)BIG_BUF_SIZE) != 0)
+        TEST_ERROR;
+
+    /* Fork child process to verify that the data at [1024, 2014] does get written to disk */
+    if((pid = HDfork()) < 0) {
+        HDperror("fork");
+        FAIL_STACK_ERROR;
+    } else if(0 == pid) { /* Child process */
+	    /* Run the reader */
+	    status = HDexecv(SWMR_READER, new_argv);
+	    printf("errno from execv = %s\n", strerror(errno));
+        FAIL_STACK_ERROR;
+    } /* end if */
+
+    /* Parent process -- wait for the child process to complete */
+    while(pid != HDwaitpid(pid, &status, 0))
+        /*void*/;
+
+    /* Check if child process terminates normally and its return value */
+    if(WIFEXITED(status) && !WEXITSTATUS(status)) {
+	    /* Flush the accumulator */
+	    if(accum_reset(&fio_info) < 0)
+            FAIL_STACK_ERROR;
+	    /* Close the property list */
+	    if(H5Pclose(fapl) < 0) 
+	        FAIL_STACK_ERROR;
+
+	    /* Close and remove the file */
+	    if(H5Fclose(fid) < 0) 
+	        FAIL_STACK_ERROR;
+	    HDremove(SWMR_FILENAME);
+
+        /* Release memory */
+        if(wbuf2)
+            HDfree(wbuf2);
+        if(rbuf)
+            HDfree(rbuf);
+        PASSED();
+        return 0;
+    } /* end if */
+
+error:
+    /* Closing and remove the file */
+    H5Pclose(fapl);
+    H5Fclose(fid);
+    HDremove(SWMR_FILENAME);
+    /* Release memory */
+    if(wbuf2)
+        HDfree(wbuf2);
+    if(rbuf)
+        HDfree(rbuf);
+
+    return 1;
+
+#endif
+
+} /* end test_swmr_write_big() */
+
 
 /*-------------------------------------------------------------------------
  * Function:    accum_printf
diff --git a/test/accum_swmr_reader.c b/test/accum_swmr_reader.c
new file mode 100644
index 0000000..d98fe70
--- /dev/null
+++ b/test/accum_swmr_reader.c
@@ -0,0 +1,99 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
+ * access to either file, you may request a copy from help@hdfgroup.org.     *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+#include "h5test.h"
+
+#define H5F_FRIEND		/*suppress error about including H5Fpkg	  */
+#define H5FD_FRIEND		/*suppress error about including H5FDpkg	  */
+#define H5FD_TESTING
+
+#include "H5Fpkg.h"
+#include "H5FDpkg.h"
+#include "H5Iprivate.h"
+
+/* Filename: this is the same as the define in accum.c used by test_swmr_write_big() */
+#define SWMR_FILENAME "accum_swmr_big.h5"
+
+
+/*-------------------------------------------------------------------------
+ * Function:    main
+ * 
+ * Purpose:     This is the reader forked/execved by "test_swmr_write_big()" 
+ *		        test in accum.c.  The reader reads at address 1024 from the file
+ *		        and verifies that the metadata in the accumulator at address
+ * 		        1024 does get written to disk.
+ * 
+ * Return:      Success: EXIT_SUCCESS
+ *              Failure: EXIT_FAILURE
+ * 
+ * Programmer:  Vailin Choi; June 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+main(void)
+{
+    hid_t fid = -1;	        /* File ID */
+    hid_t fapl = -1;        /* file access property list ID */
+    H5F_t *f = NULL;	    /* File pointer */
+    unsigned u;		        /* Local index variable */
+    uint8_t rbuf[1024];	    /* Buffer for reading */
+    uint8_t buf[1024];	    /* Buffer for holding the expected data */
+    char *driver = NULL;    /* VFD string (from env variable) */
+
+    /* Skip this test if SWMR I/O is not supported for the VFD specified
+     * by the environment variable.
+     */
+    driver = HDgetenv("HDF5_DRIVER");
+    if(!H5FD_supports_swmr_test(driver)) {
+        return EXIT_SUCCESS;
+    }
+
+    /* Initialize buffers */
+    for(u = 0; u < 1024; u++) {
+        rbuf[u] = 0;	/* The buffer for reading */
+        buf[u] = 1;	/* The expected data should be all 1s */
+    }
+
+    if((fapl = h5_fileaccess()) < 0)
+        FAIL_STACK_ERROR
+
+    /* Open the file with SWMR_READ */
+    if((fid = H5Fopen(SWMR_FILENAME, H5F_ACC_RDONLY | H5F_ACC_SWMR_READ, fapl)) < 0)
+	    FAIL_STACK_ERROR
+
+    /* Get H5F_t * to internal file structure */
+    if(NULL == (f = (H5F_t *)H5I_object(fid))) 
+	    FAIL_STACK_ERROR
+
+    /* Should read in [1024, 2024] with buf data */
+    if(H5F_block_read(f, H5FD_MEM_DEFAULT, (haddr_t)1024, (size_t)1024, H5AC_ind_read_dxpl_id, rbuf) < 0)
+	    FAIL_STACK_ERROR;
+
+    /* Verify the data read is correct */
+    if(HDmemcmp(buf, rbuf, (size_t)1024) != 0) 
+	    TEST_ERROR;
+
+    /* CLose the file */
+    if(H5Pclose(fapl) < 0)
+	    FAIL_STACK_ERROR;
+    if(H5Fclose(fid) < 0)
+	    FAIL_STACK_ERROR;
+
+    return EXIT_SUCCESS;
+
+error: 
+    H5Fclose(fid);
+    return EXIT_FAILURE;
+} /* end main() */
+
diff --git a/test/cork.c b/test/cork.c
index 95f08b5..6cca163 100644
--- a/test/cork.c
+++ b/test/cork.c
@@ -66,14 +66,14 @@
 /* ===================== */
 
 /* Tests */
-static unsigned test_objs_cork(hbool_t new_format);
-static unsigned test_dset_cork(hbool_t new_format);
+static unsigned test_objs_cork(hbool_t swmr, hbool_t new_format);
+static unsigned test_dset_cork(hbool_t swmr, hbool_t new_format);
 static unsigned verify_old_dset_cork(void);
-static unsigned verify_obj_dset_cork(void);
-static unsigned verify_dset_cork(hbool_t new_format);
-static unsigned verify_group_cork(void);
-static unsigned verify_named_cork(void);
-static unsigned verify_multiple_cork(void);
+static unsigned verify_obj_dset_cork(hbool_t swmr);
+static unsigned verify_dset_cork(hbool_t swmr, hbool_t new_format);
+static unsigned verify_group_cork(hbool_t swmr);
+static unsigned verify_named_cork(hbool_t swmr);
+static unsigned verify_multiple_cork(hbool_t swmr);
 
 
 /*-------------------------------------------------------------------------
@@ -284,7 +284,7 @@ error:
  *-------------------------------------------------------------------------
  */
 static unsigned
-verify_obj_dset_cork(void)
+verify_obj_dset_cork(hbool_t swmr)
 {
     /* Variable Declarations */
     hid_t fid = -1;     /* File ID */
@@ -301,7 +301,11 @@ verify_obj_dset_cork(void)
     char attrname[500];         /* Name of attribute */
     unsigned flags;     /* File access flags */
 
-    TESTING("cork status for dataset objects with attributes");
+    if(swmr) {
+        TESTING("cork status for dataset objects with attributes (SWMR)");
+    } else {
+        TESTING("cork status for dataset objects with attributes");
+    }
 
     /* Create fapl */
     if((fapl = H5Pcreate(H5P_FILE_ACCESS)) < 0)
@@ -312,6 +316,8 @@ verify_obj_dset_cork(void)
 
     /* Create the file with/without SWMR access */
     flags = H5F_ACC_TRUNC;
+    if(swmr)
+        flags |= H5F_ACC_SWMR_WRITE;
     if((fid = H5Fcreate(FILENAME, flags, H5P_DEFAULT, fapl)) < 0)
         TEST_ERROR
 
@@ -405,6 +411,8 @@ verify_obj_dset_cork(void)
 
     /* Re-open the file */
     flags = H5F_ACC_RDWR;
+    if(swmr)
+        flags |= H5F_ACC_SWMR_WRITE;
     if((fid = H5Fopen(FILENAME, flags, fapl)) < 0) 
         TEST_ERROR
 
@@ -478,7 +486,7 @@ error:
  *-------------------------------------------------------------------------
  */
 static unsigned
-verify_dset_cork(hbool_t new_format)
+verify_dset_cork(hbool_t swmr, hbool_t new_format)
 {
     /* Variable Declarations */
     hid_t fid = -1;                     /* File ID */
@@ -494,10 +502,18 @@ verify_dset_cork(hbool_t new_format)
     unsigned flags;             /* File access flags */
 
     /* Testing Macro */
-    if(new_format) {
-        TESTING("cork status for chunked datasets with different indexing types (latest)");
+    if(swmr) {
+        if(new_format) {
+            TESTING("cork status for chunked datasets with different indexing types (SWMR & latest)");
+        } else {
+            TESTING("cork status for chunked datasets with different indexing types (SWMR & non-latest)");
+        } /* end if */
     } else {
-        TESTING("cork status for chunked datasets with different indexing types (non-latest)");
+        if(new_format) {
+            TESTING("cork status for chunked datasets with different indexing types (non-SWMR & latest)");
+        } else {
+            TESTING("cork status for chunked datasets with different indexing types (non-SWMR & non-latest)");
+        } /* end if */
     } /* end if */
 
     /* Create fapl */
@@ -511,6 +527,8 @@ verify_dset_cork(hbool_t new_format)
 
     /* Create the file */
     flags = H5F_ACC_TRUNC;
+    if(swmr)
+        flags |= H5F_ACC_SWMR_WRITE;
     if((fid = H5Fcreate(FILENAME, flags, H5P_DEFAULT, fapl)) < 0)
         TEST_ERROR
 
@@ -608,6 +626,8 @@ verify_dset_cork(hbool_t new_format)
 
     /* Reopen the file */
     flags = H5F_ACC_RDWR;
+    if(swmr)
+        flags |= H5F_ACC_SWMR_WRITE;
     if((fid = H5Fopen(FILENAME, flags, fapl)) < 0)
         TEST_ERROR
 
@@ -704,7 +724,7 @@ error:
  *-------------------------------------------------------------------------
  */
 static unsigned
-verify_group_cork(void)
+verify_group_cork(hbool_t swmr)
 {
     /* Variable Declarations */
     hid_t fid = -1;                     /* File ID */
@@ -718,7 +738,11 @@ verify_group_cork(void)
     int i = 0;                          /* Local index variable */
 
     /* Testing Macro */
-    TESTING("cork status for groups");
+    if(swmr) {
+        TESTING("cork status for groups (SWMR)");
+    } else {
+        TESTING("cork status for groups");
+    }
 
     /* Create fapl */
     if((fapl = H5Pcreate(H5P_FILE_ACCESS)) < 0)
@@ -729,6 +753,8 @@ verify_group_cork(void)
 
     /* Create the file */
     flags = H5F_ACC_TRUNC;
+    if(swmr)
+        flags |= H5F_ACC_SWMR_WRITE;
     if((fid = H5Fcreate(FILENAME, flags, H5P_DEFAULT, fapl)) < 0)
         TEST_ERROR
 
@@ -784,6 +810,8 @@ verify_group_cork(void)
 
     /* Re-open the file and the three groups */
     flags = H5F_ACC_RDWR;
+    if(swmr)
+        flags |= H5F_ACC_SWMR_WRITE;
     if((fid = H5Fopen(FILENAME, flags, fapl)) < 0)
         FAIL_STACK_ERROR
     if((gid = H5Gopen2(fid, GRP, H5P_DEFAULT)) < 0) 
@@ -863,7 +891,7 @@ error:
  *-------------------------------------------------------------------------
  */
 static unsigned
-verify_named_cork(void)
+verify_named_cork(hbool_t swmr)
 {
     /* Variable Declarations */
     hid_t fid = -1;                     /* File ID */
@@ -879,7 +907,11 @@ verify_named_cork(void)
     int i = 0;                          /* Local index variable */
 
     /* Testing Macro */
-    TESTING("cork status for named datatypes");
+    if(swmr) {
+        TESTING("cork status for named datatypes (SWMR)");
+    } else {
+        TESTING("cork status for named datatypes");
+    }
 
     /* Create fapl */
     if((fapl = H5Pcreate(H5P_FILE_ACCESS)) < 0)
@@ -890,6 +922,8 @@ verify_named_cork(void)
 
     /* Create the file */
     flags = H5F_ACC_TRUNC;
+    if(swmr)
+        flags |= H5F_ACC_SWMR_WRITE;
     if((fid = H5Fcreate(FILENAME, flags, H5P_DEFAULT, fapl)) < 0)
         TEST_ERROR
 
@@ -982,6 +1016,8 @@ verify_named_cork(void)
 
     /* Re-open the file and the three groups */
     flags = H5F_ACC_RDWR;
+    if(swmr)
+        flags |= H5F_ACC_SWMR_WRITE;
     if((fid = H5Fopen(FILENAME, flags, fapl)) < 0)
         FAIL_STACK_ERROR
     if((gid = H5Gopen2(fid, GRP, H5P_DEFAULT)) < 0) 
@@ -1131,7 +1167,7 @@ error:
  *-------------------------------------------------------------------------
  */
 static unsigned
-verify_multiple_cork(void)
+verify_multiple_cork(hbool_t swmr)
 {
     /* Variable Declarations */
     hid_t fid1 = -1, fid2 = -1;     /* File ID */
@@ -1150,7 +1186,11 @@ verify_multiple_cork(void)
     herr_t ret;                     /* Return value */
 
     /* Testing Macro */
-    TESTING("cork status for multiple opens");
+    if(swmr) {
+        TESTING("cork status for multiple opens (SWMR)");
+    } else {
+        TESTING("cork status for multiple opens");
+    }
 
     /* Create fapl */
     if((fapl = H5Pcreate(H5P_FILE_ACCESS)) < 0)
@@ -1161,6 +1201,8 @@ verify_multiple_cork(void)
 
     /* Create the file */
     flags = H5F_ACC_TRUNC;
+    if(swmr)
+        flags |= H5F_ACC_SWMR_WRITE;
     if((fid1 = H5Fcreate(FILENAME, flags, H5P_DEFAULT, fapl)) < 0)
         TEST_ERROR
 
@@ -1212,6 +1254,8 @@ verify_multiple_cork(void)
 
     /* Open the file twice: fid1, fid2 */
     flags = H5F_ACC_RDWR;
+    if(swmr)
+        flags |= H5F_ACC_SWMR_WRITE;
     if((fid1 = H5Fopen(FILENAME, flags, fapl)) < 0)
         TEST_ERROR
     if((fid2 = H5Fopen(FILENAME, flags, fapl)) < 0)
@@ -1484,7 +1528,7 @@ error:
  *-------------------------------------------------------------------------
  */
 static unsigned
-test_objs_cork(hbool_t new_format)
+test_objs_cork(hbool_t swmr, hbool_t new_format)
 {
     hid_t       fid;                    /* HDF5 File ID */
     hid_t       fapl;                   /* File access property list */
@@ -1493,14 +1537,25 @@ test_objs_cork(hbool_t new_format)
     hid_t   aid;            /* Attribute ID */
     hsize_t     dims[RANK];     /* Dataset dimension sizes */
     hbool_t     corked;         /* Cork status of an object */
+    unsigned flags;             /* File access flags */
     herr_t      ret;                    /* Return value */
 
     /* Testing Macro */
     if(new_format) {
-        TESTING("H5Odisable_mdc_flushes/H5Oenable_mdc_flushes/H5Oare_mdc_flushes_disabled (new library format)");
+        if(swmr) {
+            TESTING("H5Odisable_mdc_flushes/H5Oenable_mdc_flushes/H5Oare_mdc_flushes_disabled (new library format) (SWMR)");
+        } /* end if */
+        else {
+            TESTING("H5Odisable_mdc_flushes/H5Oenable_mdc_flushes/H5Oare_mdc_flushes_disabled (new library format)");
+        } /* end else */
     } else {
-        TESTING("H5Odisable_mdc_flushes/H5Oenable_mdc_flushes/H5Oare_mdc_flushes_disabled (old library format)");
-    } /* end if */
+        if(swmr) {
+            TESTING("H5Odisable_mdc_flushes/H5Oenable_mdc_flushes/H5Oare_mdc_flushes_disabled (old library format) (SWMR)");
+        } /* end if */
+        else {
+            TESTING("H5Odisable_mdc_flushes/H5Oenable_mdc_flushes/H5Oare_mdc_flushes_disabled (old library format)");
+        } /* end else */
+    } /* end else */
 
     /* Create fapl */
     if((fapl = H5Pcreate(H5P_FILE_ACCESS)) < 0)
@@ -1512,8 +1567,11 @@ test_objs_cork(hbool_t new_format)
             TEST_ERROR
     } /* end if */
 
-    /* Create an HDF5 file */
-    if((fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+    /* Create the file with/without SWMR access */
+    flags = H5F_ACC_TRUNC;
+    if(swmr)
+        flags |= H5F_ACC_SWMR_WRITE;
+    if((fid = H5Fcreate(FILENAME, flags, H5P_DEFAULT, fapl)) < 0)
         TEST_ERROR
 
     /* Create group */
@@ -1753,7 +1811,7 @@ error:
  *-------------------------------------------------------------------------
  */
 static unsigned
-test_dset_cork(hbool_t new_format)
+test_dset_cork(hbool_t swmr, hbool_t new_format)
 {
     hid_t       fid;                            /* File ID */
     hid_t       fapl;                           /* File access property list */
@@ -1770,12 +1828,23 @@ test_dset_cork(hbool_t new_format)
     int     data[DIMS0][DIMS1];     /* Data buffer */
     int     rbuf[DIMS0][DIMS1];     /* Data buffer */
     hbool_t     corked;             /* Cork status of an object */
+    unsigned flags;                 /* File access flags */
 
     /* Testing Macro */
     if(new_format) {
-        TESTING("H5Odisable_mdc_flushes/H5Oenable_mdc_flushes/H5Oare_mdc_flushes_disabled on datasets (new library format)");
+        if(swmr) {
+            TESTING("H5Odisable_mdc_flushes/H5Oenable_mdc_flushes/H5Oare_mdc_flushes_disabled on datasets (new library format) (SWMR)");
+        } /* end if */
+        else {
+            TESTING("H5Odisable_mdc_flushes/H5Oenable_mdc_flushes/H5Oare_mdc_flushes_disabled on datasets (new library format)");
+        } /* end else */
     } else {
-        TESTING("H5Odisable_mdc_flushes/H5Oenable_mdc_flushes/H5Oare_mdc_flushes_disabled on datasets (old library format)");
+        if(swmr) {
+            TESTING("H5Odisable_mdc_flushes/H5Oenable_mdc_flushes/H5Oare_mdc_flushes_disabled on datasets (old library format) (SWMR)");
+        } /* end if */
+        else {
+            TESTING("H5Odisable_mdc_flushes/H5Oenable_mdc_flushes/H5Oare_mdc_flushes_disabled on datasets (old library format)");
+        } /* end else */
     } /* end if */
 
     /* Create fapl */
@@ -1788,8 +1857,11 @@ test_dset_cork(hbool_t new_format)
             TEST_ERROR
     } /* end if */
 
-    /* Create a new HDF5 file */
-    if((fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+    /* Create the file with/without SWMR access */
+    flags = H5F_ACC_TRUNC;
+    if(swmr)
+        flags |= H5F_ACC_SWMR_WRITE;
+    if((fid = H5Fcreate(FILENAME, flags, H5P_DEFAULT, fapl)) < 0)
         TEST_ERROR
 
     /* Create a group */
@@ -2070,26 +2142,29 @@ error:
 int 
 main(void) 
 {
+    unsigned swmr;              /* Loop over SWMR/non-SWMR */
     unsigned nerrs = 0;         /* Error Encountered */
     
     /* Test for dataset created with old library format */
     nerrs += verify_old_dset_cork();
 
-    /* Tests with new/old library format */
-    /* This is the test moved from th5o.c: test_h5o_cork() */
-    nerrs += test_objs_cork(TRUE);
-    nerrs += test_objs_cork(FALSE);
-    /* This is the test moved from th5o.c: test_h5o_cork_dataset() */
-    nerrs += test_dset_cork(TRUE);
-    nerrs += test_dset_cork(FALSE);
-
-    /* Tests with/without SWMR access */
-    nerrs += verify_obj_dset_cork();
-    nerrs += verify_dset_cork(TRUE); 
-    nerrs += verify_dset_cork(FALSE); 
-    nerrs += verify_group_cork(); 
-    nerrs += verify_named_cork();
-    nerrs += verify_multiple_cork();
+    for(swmr = 0; swmr <= 1; swmr++) {
+        /* Tests with new/old library format */
+        /* This is the test moved from th5o.c: test_h5o_cork() */
+        nerrs += test_objs_cork(swmr, TRUE);
+        nerrs += test_objs_cork(swmr, FALSE);
+        /* This is the test moved from th5o.c: test_h5o_cork_dataset() */
+        nerrs += test_dset_cork(swmr, TRUE);
+        nerrs += test_dset_cork(swmr, FALSE);
+
+        /* Tests with/without SWMR access */
+        nerrs += verify_obj_dset_cork(swmr);
+        nerrs += verify_dset_cork(swmr, TRUE); 
+        nerrs += verify_dset_cork(swmr, FALSE); 
+        nerrs += verify_group_cork(swmr); 
+        nerrs += verify_named_cork(swmr); 
+        nerrs += verify_multiple_cork(swmr);
+    } /* end for */
 
     /* Delete test files */
     HDremove(FILENAME);
diff --git a/test/dsets.c b/test/dsets.c
index 31ef88a..d086c58 100644
--- a/test/dsets.c
+++ b/test/dsets.c
@@ -12667,7 +12667,7 @@ main(void)
     /* Don't run this test using certain file drivers */
     envval = HDgetenv("HDF5_DRIVER");
     if(envval == NULL)
-        envval = "nomatch";
+        envval = "sec2";
 
     /* Set the random # seed */
     HDsrandom((unsigned)HDtime(NULL));
diff --git a/test/links.c b/test/links.c
index 2c841f0..182eb6c 100644
--- a/test/links.c
+++ b/test/links.c
@@ -27,8 +27,12 @@
 #define H5G_FRIEND		/*suppress error about including H5Gpkg	  */
 #define H5G_TESTING
 
+#define H5FD_FRIEND		/*suppress error about including H5FDpkg	  */
+#define H5FD_TESTING
+
 #include "h5test.h"
 #include "H5srcdir.h"
+#include "H5FDpkg.h"            /* File drivers         */
 #include "H5Gpkg.h"		/* Groups 				*/
 #include "H5Iprivate.h"		/* IDs			  		*/
 #include "H5Lprivate.h"         /* Links                                */
@@ -3951,7 +3955,7 @@ external_set_elink_fapl3(hbool_t new_format)
  *-------------------------------------------------------------------------
  */
 static int
-external_set_elink_acc_flags(hid_t fapl, hbool_t new_format)
+external_set_elink_acc_flags(const char *env_h5_drvr, hid_t fapl, hbool_t new_format)
 {
     hid_t       file1 = -1, file2 = -1, group = -1, subgroup = -1, gapl = -1;
     char        filename1[NAME_BUF_SIZE],
@@ -4010,6 +4014,15 @@ external_set_elink_acc_flags(hid_t fapl, hbool_t new_format)
     } H5E_END_TRY;
     if(subgroup != FAIL) TEST_ERROR
 
+    /* Attempt to set SWMR flags on gapl.
+     * This is just a smoke check of the flags. The actual external link
+     * functionality is tested in the SWMR tests.
+     */
+    /* Set SWMR reader flags on gapl */
+    if(H5Pset_elink_acc_flags(gapl, H5F_ACC_RDONLY | H5F_ACC_SWMR_READ) < 0) TEST_ERROR
+    /* Set SWMR writer flags on gapl */
+    if(H5Pset_elink_acc_flags(gapl, H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE) < 0) TEST_ERROR
+
     /* Attempt to set invalid flags on gapl */
     H5E_BEGIN_TRY {
         ret = H5Pset_elink_acc_flags(gapl, H5F_ACC_TRUNC);
@@ -4023,10 +4036,94 @@ external_set_elink_acc_flags(hid_t fapl, hbool_t new_format)
         ret = H5Pset_elink_acc_flags(gapl, H5F_ACC_CREAT);
     } H5E_END_TRY;
     if(ret != FAIL) TEST_ERROR
+    /* SWMR reader with write access */
+    H5E_BEGIN_TRY {
+        ret = H5Pset_elink_acc_flags(gapl, H5F_ACC_RDWR | H5F_ACC_SWMR_READ);
+    } H5E_END_TRY;
+    if(ret != FAIL) TEST_ERROR
+    /* SWMR writer with read-only access */
+    H5E_BEGIN_TRY {
+        ret = H5Pset_elink_acc_flags(gapl, H5F_ACC_RDONLY | H5F_ACC_SWMR_WRITE);
+    } H5E_END_TRY;
+    if(ret != FAIL) TEST_ERROR
 
     /* Close file1 */
     if(H5Fclose(file1) < 0) TEST_ERROR
 
+    /* Only run this part with VFDs that support SWMR */
+    if(H5FD_supports_swmr_test(env_h5_drvr)) {
+
+        /* Reopen file1, with read-write and SWMR-write access */
+        /* Only supported under the latest file format */
+        if(new_format) {
+            if((file1 = H5Fopen(filename1, H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE, fapl)) < 0) FAIL_STACK_ERROR
+
+            /* Open a group through the external link using default gapl */
+            if((group = H5Gopen2(file1, "/ext_link/group", H5P_DEFAULT)) < 0) FAIL_STACK_ERROR
+
+            /* Verify that the correct parameters have been set on file2 */
+            if((file2 = H5Iget_file_id(group)) < 0) FAIL_STACK_ERROR
+            if(H5Fget_intent(file2, &flags) < 0) FAIL_STACK_ERROR
+            if(flags != (H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE)) TEST_ERROR
+
+            /* Close file2 and group */
+            if(H5Gclose(group) < 0) FAIL_STACK_ERROR
+            if(H5Fclose(file2) < 0) FAIL_STACK_ERROR
+
+            /* Set elink access flags on gapl to be H5F_ACC_RDWR (dropping SWMR_WRITE) */
+            if(H5Pset_elink_acc_flags(gapl, H5F_ACC_RDWR) < 0) FAIL_STACK_ERROR
+
+            /* Open a group through the external link using gapl */
+            if((group = H5Gopen2(file1, "/ext_link/group", gapl)) < 0) FAIL_STACK_ERROR
+
+            /* Verify that the correct parameters have been set on file2 */
+            if((file2 = H5Iget_file_id(group)) < 0) FAIL_STACK_ERROR
+            if(H5Fget_intent(file2, &flags) < 0) FAIL_STACK_ERROR
+            if(flags != H5F_ACC_RDWR) TEST_ERROR
+
+            /* Close file2 and group */
+            if(H5Gclose(group) < 0) FAIL_STACK_ERROR
+            if(H5Fclose(file2) < 0) FAIL_STACK_ERROR
+
+            /* Close file1 */
+            if(H5Fclose(file1) < 0) TEST_ERROR
+        }
+
+        /* Reopen file1, with read-only and SWMR-read access */
+        if((file1 = H5Fopen(filename1, H5F_ACC_RDONLY | H5F_ACC_SWMR_READ, fapl)) < 0) FAIL_STACK_ERROR
+
+        /* Open a group through the external link using default gapl */
+        if((group = H5Gopen2(file1, "/ext_link/group", H5P_DEFAULT)) < 0) FAIL_STACK_ERROR
+
+        /* Verify that the correct parameters have been set on file2 */
+        if((file2 = H5Iget_file_id(group)) < 0) FAIL_STACK_ERROR
+        if(H5Fget_intent(file2, &flags) < 0) FAIL_STACK_ERROR
+        if(flags != (H5F_ACC_RDONLY | H5F_ACC_SWMR_READ)) TEST_ERROR
+
+        /* Close file2 and group */
+        if(H5Gclose(group) < 0) FAIL_STACK_ERROR
+        if(H5Fclose(file2) < 0) FAIL_STACK_ERROR
+
+        /* Set elink access flags on gapl to be H5F_ACC_RDWR (dropping SWMR_WRITE) */
+        if(H5Pset_elink_acc_flags(gapl, H5F_ACC_RDONLY) < 0) FAIL_STACK_ERROR
+
+        /* Open a group through the external link using gapl */
+        if((group = H5Gopen2(file1, "/ext_link/group", gapl)) < 0) FAIL_STACK_ERROR
+
+        /* Verify that the correct parameters have been set on file2 */
+        if((file2 = H5Iget_file_id(group)) < 0) FAIL_STACK_ERROR
+        if(H5Fget_intent(file2, &flags) < 0) FAIL_STACK_ERROR
+        if(flags != H5F_ACC_RDONLY) TEST_ERROR
+
+        /* Close file2 and group */
+        if(H5Gclose(group) < 0) FAIL_STACK_ERROR
+        if(H5Fclose(file2) < 0) FAIL_STACK_ERROR
+
+        /* Close file1 */
+        if(H5Fclose(file1) < 0) TEST_ERROR
+    } /* end if */
+
+
     /* Verify that H5Fcreate and H5Fopen reject H5F_ACC_DEFAULT */
     H5E_BEGIN_TRY {
         file1 = H5Fcreate(filename1, H5F_ACC_DEFAULT, H5P_DEFAULT, fapl);
@@ -14840,7 +14937,7 @@ main(void)
 
         /* This test cannot run with the EFC because the EFC cannot currently
          * reopen a cached file with a different intent */
-        nerrors += external_set_elink_acc_flags(my_fapl, new_format) < 0 ? 1 : 0;
+        nerrors += external_set_elink_acc_flags(env_h5_drvr, my_fapl, new_format) < 0 ? 1 : 0;
 
         /* Try external link tests both with and without the external file cache
          */
diff --git a/test/ohdr.c b/test/ohdr.c
index f06dc71..2ac9866 100644
--- a/test/ohdr.c
+++ b/test/ohdr.c
@@ -44,6 +44,11 @@ const char *FILENAME[] = {
  */
 #define FILE_BOGUS "tbogus.h5"
 
+/*  */
+#define FILE_OHDR_SWMR "ohdr_swmr.h5"
+#define DSET_NAME "COMPACT_DSET"
+#define OBJ_VERSION_LATEST 2
+
 /*
  *  Verify that messages are moved forward into a "continuation message":
  *	Create an object header with several continuation chunks
@@ -297,6 +302,152 @@ error:
 } /* test_ohdr_cache() */
 
 /*
+ *  To exercise the coding for the re-read of the object header for SWMR access.
+ *  When the object header is read in H5O_load() of H5Ocache.c, the library initially reads
+ *  H5O_SPEC_READ_SIZE (512, currently)  bytes for decoding, then reads the
+ *  remaining bytes later if the object header is greater than H5O_SPEC_READ_SIZE
+ *  bytes.  For SWMR access, the read should be done all at one time.
+ */
+static herr_t
+test_ohdr_swmr(hbool_t new_format)
+{
+    hid_t fid = -1;			    /* File ID */
+    hid_t fapl = -1;			/* File access property list */
+    hid_t did = -1;			    /* Dataset ID */
+    hid_t sid = -1;             /* Dataspace ID */
+    hid_t plist = -1;			/* Dataset creation property list */
+    size_t compact_size = 1024;	/* The size of compact dataset */
+    int *wbuf = NULL;			/* Buffer for writing */
+    hsize_t dims[1];			/* Dimension sizes */
+    size_t u;		            /* Iterator */
+    int n;                      /* Data variable */
+    H5O_info_t obj_info;		/* Information for the object */
+
+    if(new_format) {
+        TESTING("exercise the coding for the re-read of the object header for SWMR access: latest-format");
+    } else {
+        TESTING("exercise the coding for the re-read of the object header for SWMR access: non-latest-format");
+    } /* end if */
+
+    /* File access property list */
+    if((fapl = H5Pcreate(H5P_FILE_ACCESS)) < 0)
+        FAIL_STACK_ERROR
+
+    /* Create the file with/without latest format: ensure version 2 object header for SWMR */
+    if(new_format)  {
+        /* Set to use latest library format */
+        if(H5Pset_libver_bounds(fapl, H5F_LIBVER_LATEST, H5F_LIBVER_LATEST) < 0)
+            FAIL_STACK_ERROR
+
+        if((fid = H5Fcreate(FILE_OHDR_SWMR, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+            TEST_ERROR
+    } /* end if */
+    else {
+        if((fid = H5Fcreate(FILE_OHDR_SWMR, H5F_ACC_TRUNC|H5F_ACC_SWMR_WRITE, H5P_DEFAULT, fapl)) < 0)
+            TEST_ERROR
+    } /* end else */
+
+    /* Initialize data */
+    wbuf = (int *)HDcalloc(compact_size, sizeof(int));
+    n = 0;
+    for(u = 0; u < compact_size; u++)
+        wbuf[u] = n++;
+
+    /* Create a small data space for compact dataset */
+    dims[0] = (hsize_t)compact_size;
+    if((sid = H5Screate_simple(1, dims, NULL)) < 0)
+        FAIL_STACK_ERROR
+    
+    /* Create property list for compact dataset creation */
+    if((plist = H5Pcreate(H5P_DATASET_CREATE)) < 0)
+        FAIL_STACK_ERROR
+
+    /* Set the layout for the compact dataset */
+    if(H5Pset_layout(plist, H5D_COMPACT) < 0)
+        FAIL_STACK_ERROR
+
+    /* Create a compact dataset */
+    if((did = H5Dcreate2(fid, DSET_NAME, H5T_NATIVE_INT, sid, H5P_DEFAULT, plist, H5P_DEFAULT)) < 0)
+        FAIL_STACK_ERROR
+
+    /* Write to the compact dataset */
+    if(H5Dwrite(did, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, wbuf) < 0)
+        FAIL_STACK_ERROR
+
+    /* Close the dataset */
+    if(H5Dclose(did) < 0)
+        FAIL_STACK_ERROR
+
+    /* Close the file */
+    if(H5Fclose(fid) < 0)
+        FAIL_STACK_ERROR
+
+    /* Open the file for SWMR write with/without latest format */
+    if((fid = H5Fopen(FILE_OHDR_SWMR, H5F_ACC_RDWR|H5F_ACC_SWMR_WRITE, fapl)) < 0)
+        FAIL_STACK_ERROR
+
+    /* Open the compact dataset */
+    if((did = H5Dopen2(fid, DSET_NAME, H5P_DEFAULT)) < 0)
+        FAIL_STACK_ERROR
+
+    /* Get the object information */
+    if(H5Oget_info(did, &obj_info) < 0)
+        FAIL_STACK_ERROR
+
+    if(obj_info.hdr.version != OBJ_VERSION_LATEST)
+        FAIL_STACK_ERROR
+
+    /* The size of object header should be greater than the speculative read size of H5O_SPEC_READ_SIZE */
+    /* This will exercise the coding for the re-read of the object header for SWMR access */
+    if(obj_info.hdr.space.total < H5O_SPEC_READ_SIZE)
+        TEST_ERROR;
+
+    /* Close the dataset */
+    if(H5Dclose(did) < 0)
+        FAIL_STACK_ERROR
+
+    /* Close the file */
+    if(H5Fclose(fid) < 0)
+        FAIL_STACK_ERROR
+
+    /* Close the dataspace */
+    if(H5Sclose(sid) < 0)
+        FAIL_STACK_ERROR
+
+    /* Close the dataset creation property list */
+    if(H5Pclose(plist) < 0)
+        FAIL_STACK_ERROR
+
+    /* Close the file access property list */
+    if(H5Pclose(fapl) < 0)
+        FAIL_STACK_ERROR
+
+    /* Remove the test file */
+    if(HDremove(FILE_OHDR_SWMR) < 0)
+        FAIL_STACK_ERROR
+
+    /* Free the buffer */
+    HDfree(wbuf);
+
+    PASSED();
+
+    return SUCCEED;
+
+error:
+    H5E_BEGIN_TRY {
+        H5Fclose(fid);
+        H5Dclose(did);
+        H5Sclose(sid);
+        H5Pclose(plist);
+        H5Pclose(fapl);
+        HDremove(FILE_OHDR_SWMR);
+        HDfree(wbuf);
+    } H5E_END_TRY;
+
+    return FAIL;
+} /* test_ohdr_swmr() */
+
+/*
  *  To test objects with unknown messages in a file with:
  *  	a) H5O_BOGUS_VALID_ID:
  *	   --the bogus_id is within the range of H5O_msg_class_g[]
@@ -832,6 +983,10 @@ main(void)
     /* Verify symbol table messages are cached */
     if(h5_verify_cached_stabs(FILENAME, fapl) < 0) TEST_ERROR
 
+    /* A test to exercise the re-read of the object header for SWMR access */
+    if(test_ohdr_swmr(TRUE) < 0) TEST_ERROR
+    if(test_ohdr_swmr(FALSE) < 0) TEST_ERROR
+
     HDputs("All object header tests passed.");
     h5_cleanup(FILENAME, fapl);
     return 0;
diff --git a/test/tfile.c b/test/tfile.c
index 82905d5..19a2df4 100644
--- a/test/tfile.c
+++ b/test/tfile.c
@@ -3847,7 +3847,8 @@ test_libver_macros(void)
     VERIFY(H5_VERSION_GE(major-1,minor,release+1), TRUE, "H5_VERSION_GE");
     VERIFY(H5_VERSION_GE(major,minor-1,release), TRUE, "H5_VERSION_GE");
     VERIFY(H5_VERSION_GE(major,minor-1,release+1), TRUE, "H5_VERSION_GE");
-    VERIFY(H5_VERSION_GE(major,minor,release-1), TRUE, "H5_VERSION_GE");
+    if(H5_VERS_RELEASE > 0)
+        VERIFY(H5_VERSION_GE(major,minor,release-1), TRUE, "H5_VERSION_GE");
 
     VERIFY(H5_VERSION_GE(major+1,minor,release), FALSE, "H5_VERSION_GE");
     VERIFY(H5_VERSION_GE(major+1,minor-1,release), FALSE, "H5_VERSION_GE");
@@ -3869,7 +3870,8 @@ test_libver_macros(void)
     VERIFY(H5_VERSION_LE(major-1,minor+1,release+1), FALSE, "H5_VERSION_LE");
     VERIFY(H5_VERSION_LE(major,minor-1,release), FALSE, "H5_VERSION_LE");
     VERIFY(H5_VERSION_LE(major,minor-1,release+1), FALSE, "H5_VERSION_LE");
-    VERIFY(H5_VERSION_LE(major,minor,release-1), FALSE, "H5_VERSION_LE");
+    if(H5_VERS_RELEASE > 0)
+        VERIFY(H5_VERSION_LE(major,minor,release-1), FALSE, "H5_VERSION_LE");
 } /* test_libver_macros() */
 
 /****************************************************************