Preliminary checkins for implementation done so far:

1) Public routines: H5Pget/set_vfd_swmr_config
2) Public routine: H5Fvfd_swmr_end_tick
3) Initialization when opening a file with VFD SWMR writer
4) Tests in test/vfd_swmr.c for VFD SWMR
5) Fix a bug in src/H5Fint.c: when error is encountered after the root group is created
Note the following:
--This is WORK IN PROGRESS and will subject to change as implementation goes.
--There is test failure form enc_dec_plist.c: I will fix this when changes to the property list are settled.
--The branch is updated with the latest from develop as of 8/14/2018

1 files changed, 213 insertions, 0 deletions

diff --git a/src/H5Pfapl.c b/src/H5Pfapl.c
index 7ba9c11..a0291e6 100644
--- a/src/H5Pfapl.c
+++ b/src/H5Pfapl.c
@@ -259,6 +259,11 @@
 #define H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_ENC            H5P__encode_unsigned
 #define H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_DEC            H5P__decode_unsigned
 
+/* Definitions for the VFD SWMR configuration */
+#define H5F_ACS_VFD_SWMR_CONFIG_SIZE   sizeof(H5F_vfd_swmr_config_t)
+#define H5F_ACS_VFD_SWMR_CONFIG_DEF    H5F__DEFAULT_VFD_SWMR_CONFIG
+#define H5F_ACS_VFD_SWMR_CONFIG_ENC    H5P__facc_vfd_swmr_config_enc
+#define H5F_ACS_VFD_SWMR_CONFIG_DEC    H5P__facc_vfd_swmr_config_dec
 
 /******************/
 /* Local Typedefs */
@@ -306,6 +311,8 @@ static herr_t H5P__facc_multi_type_enc(const void *value, void **_pp, size_t *si
 static herr_t H5P__facc_multi_type_dec(const void **_pp, void *value);
 static herr_t H5P__facc_libver_type_enc(const void *value, void **_pp, size_t *size);
 static herr_t H5P__facc_libver_type_dec(const void **_pp, void *value);
+static herr_t H5P__facc_vfd_swmr_config_enc(const void *value, void **_pp, size_t *size);
+static herr_t H5P__facc_vfd_swmr_config_dec(const void **_pp, void *value);
 
 /* Metadata cache log location property callbacks */
 static herr_t H5P_facc_mdc_log_location_enc(const void *value, void **_pp, size_t *size);
@@ -398,6 +405,8 @@ static const size_t H5F_def_page_buf_size_g = H5F_ACS_PAGE_BUFFER_SIZE_DEF;
 static const unsigned H5F_def_page_buf_min_meta_perc_g = H5F_ACS_PAGE_BUFFER_MIN_META_PERC_DEF;      /* Default page buffer minimum metadata size */
 static const unsigned H5F_def_page_buf_min_raw_perc_g = H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_DEF;      /* Default page buffer mininum raw data size */
 
+static const H5F_vfd_swmr_config_t *H5F_def_vfd_swmr_config_g = H5F_ACS_VFD_SWMR_CONFIG_DEF;  /* Default vfd swmr configuration */
+
 
 /*-------------------------------------------------------------------------
  * Function:    H5P__facc_reg_prop
@@ -644,6 +653,12 @@ H5P__facc_reg_prop(H5P_genclass_t *pclass)
             NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
+    /* Register the default VFD SWMR configuration */
+    if(H5P_register_real(pclass, H5F_ACS_VFD_SWMR_CONFIG_NAME, H5F_ACS_VFD_SWMR_CONFIG_SIZE, &H5F_def_vfd_swmr_config_g,
+            NULL, NULL, NULL, H5F_ACS_VFD_SWMR_CONFIG_ENC, H5F_ACS_VFD_SWMR_CONFIG_DEC,
+            NULL, NULL, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5P__facc_reg_prop() */
@@ -3643,6 +3658,7 @@ H5P__facc_cache_config_dec(const void **_pp, void *_value)
     enc_size = *(*pp)++;
     HDassert(enc_size < 256);
     UINT64DECODE_VAR(*pp, enc_value, enc_size);
+
     config->max_size = (size_t)enc_value;
 
     enc_size = *(*pp)++;
@@ -3927,6 +3943,105 @@ H5P__facc_libver_type_dec(const void **_pp, void *_value)
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5P__facc_vfd_swmr_config_enc
+ *
+ * Purpose:     Callback routine which is called whenever the VFD SWMR config
+ *              property in the file access property list is encoded.
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ * Programmer:  Vailin Choi; July 2018
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_vfd_swmr_config_enc(const void *value, void **_pp, size_t *size)
+{
+    const H5F_vfd_swmr_config_t *config = (const H5F_vfd_swmr_config_t *)value; /* Create local aliases for values */
+    uint8_t **pp = (uint8_t **)_pp;
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity check */
+    HDassert(value);
+    HDcompile_assert(sizeof(size_t) <= sizeof(uint64_t));
+
+    if(NULL != *pp) {
+
+        /* int */
+        INT32ENCODE(*pp, (int32_t)config->version);
+        INT32ENCODE(*pp, (int32_t)config->tick_len);
+        INT32ENCODE(*pp, (int32_t)config->max_lag);
+        H5_ENCODE_UNSIGNED(*pp, config->vfd_swmr_writer);
+        H5_ENCODE_UNSIGNED(*pp, config->flush_raw_data);
+        INT32ENCODE(*pp, (int32_t)config->md_pages_reserved);
+        HDmemcpy(*pp, (const uint8_t *)(config->md_file_path), (size_t)(H5F__MAX_VFD_SWMR_FILE_NAME_LEN + 1));
+        *pp += H5F__MAX_VFD_SWMR_FILE_NAME_LEN + 1;
+        HDmemcpy(*pp, (const uint8_t *)(config->log_file_path), (size_t)(H5F__MAX_VFD_SWMR_FILE_NAME_LEN + 1));
+        *pp += H5F__MAX_VFD_SWMR_FILE_NAME_LEN + 1;
+
+    } /* end if */
+
+    /* Compute encoded size */
+    *size += ( (4 * sizeof(int32_t)) + sizeof(unsigned) + 
+               (2 * (H5F__MAX_VFD_SWMR_FILE_NAME_LEN + 1)) );
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5P__facc_vfd_swmr_config_enc() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P__facc_vfd_swmr_config_dec
+ *
+ * Purpose:     Callback routine which is called whenever the VFD SWMR
+ *              config property in the file access property list is decoded.
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ * Programmer:  Vailin Choi; July 2018
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_vfd_swmr_config_dec(const void **_pp, void *_value)
+{
+    H5F_vfd_swmr_config_t *config = (H5F_vfd_swmr_config_t *)_value;
+    const uint8_t **pp = (const uint8_t **)_pp;
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity checks */
+    HDassert(pp);
+    HDassert(*pp);
+    HDassert(config);
+    HDcompile_assert(sizeof(size_t) <= sizeof(uint64_t));
+
+    /* Set property to default value */
+    HDmemcpy(config, &H5F_def_vfd_swmr_config_g, sizeof(H5F_vfd_swmr_config_t));
+
+    /* int */
+    INT32DECODE(*pp, config->version);
+    INT32DECODE(*pp, config->tick_len);
+    INT32DECODE(*pp, config->max_lag);
+
+    H5_DECODE_UNSIGNED(*pp, config->vfd_swmr_writer);
+    H5_DECODE_UNSIGNED(*pp, config->flush_raw_data);
+
+    /* int */
+    INT32DECODE(*pp, config->md_pages_reserved);
+
+    HDstrcpy(config->md_file_path, (const char *)(*pp));
+    *pp += H5F__MAX_VFD_SWMR_FILE_NAME_LEN + 1;
+
+    HDstrcpy(config->log_file_path, (const char *)(*pp));
+    *pp += H5F__MAX_VFD_SWMR_FILE_NAME_LEN + 1;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5P__facc_vfd_swmr_config_dec() */
+
+/*-------------------------------------------------------------------------
  * Function:    H5Pset_core_write_tracking
  *
  * Purpose:    Enables/disables core VFD write tracking and page
@@ -4939,3 +5054,101 @@ done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Pget_page_buffer_size() */
 
+/*-------------------------------------------------------------------------
+ * Function:    H5Pset_vfd_swmr_config
+ *
+ * Purpose:     Set VFD SWMR configuration in the target FAPL.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Vailin Choi; July 2018
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_vfd_swmr_config(hid_t plist_id, H5F_vfd_swmr_config_t *config_ptr)
+{
+    H5P_genplist_t *plist;      /* Property list pointer */
+    size_t name_len;
+    herr_t ret_value = SUCCEED;   /* return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE2("e", "i*x", plist_id, config_ptr);
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_ACCESS)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Validate the input configuration */
+
+     /* Check args */
+    if(config_ptr == NULL)
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "NULL config_ptr on entry")
+
+    /* This field must always be set to a known version */
+    if(config_ptr->version != H5F__CURR_VFD_SWMR_CONFIG_VERSION)
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "Unknown config version")
+
+    /* This field must be >= 0 */
+    if(config_ptr->tick_len < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "tick_len must be greater than 0")
+
+    /* This field must be at least 3 */
+    if(config_ptr->max_lag < 3 )
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "max_lag must be at least 3")
+
+    /* This field must be >= 1 */
+    if(config_ptr->md_pages_reserved < 1 )
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "md_pages_reserved must be at least 1")
+
+    /* Must provide the path for the metadata file */
+    name_len = HDstrlen(config_ptr->md_file_path);
+    if(name_len == 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "md_file_path is empty")
+    else if(name_len > H5F__MAX_VFD_SWMR_FILE_NAME_LEN)
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "md_file_path is too long")
+
+    /* Set the modified config */
+    if(H5P_set(plist, H5F_ACS_VFD_SWMR_CONFIG_NAME, config_ptr) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set metadata cache initial config")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5Pset_vfd_swmr_config() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Pget_vfd_swmr_config
+ *
+ * Purpose:     Retrieve the VFD SWMR configuration from the target FAPL.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Vailin Choi; July 2018
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pget_vfd_swmr_config(hid_t plist_id, H5F_vfd_swmr_config_t *config_ptr)
+{
+    H5P_genplist_t *plist;      /* Property list pointer */
+    herr_t ret_value = SUCCEED;   /* return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE2("e", "i*x", plist_id, config_ptr);
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_ACCESS)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Validate the config_ptr */
+    if(config_ptr == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "NULL config_ptr on entry.")
+
+    /* Get the current VFD SWMR configuration */
+    if(H5P_get(plist, H5F_ACS_VFD_SWMR_CONFIG_NAME, config_ptr) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET,FAIL, "can't get VFD SWMR config")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5Pget_vfd_swmr_config() */