daos: add epoch supporting code

Added epc to daos_args_t and some supporting
functionality that paves the way for being able to pass
an epc through the command line in the future.

Signed-off-by: Dalton Bohning <daltonx.bohning@intel.com>

src/common/mfu_daos.c

@@ -633,6 +633,8 @@ daos_args_t* daos_args_new(void)
     /* By default, try to automatically determine the API */
     da->api = DAOS_API_AUTO;
 
+    da->epc = 0;
+
     return da;
 }
 
@@ -666,6 +668,18 @@ int daos_parse_api_str(
     return rc;
 }
 
+int daos_parse_epc_str(
+    const char* epc_str,
+    daos_epoch_t* epc)
+{
+    *epc = strtoull(epc_str, NULL, 10);
+    if (*epc == 0 || (*epc == ULLONG_MAX && errno != 0)) {
+        return 1;
+    }
+
+    return 0;
+}
+
 int daos_setup(
     int rank,
     char** argpaths,
@@ -1165,7 +1179,7 @@ static int daos_obj_copy(
     return rc;
 }
 
-static int daos_obj_list_oids(daos_args_t* da, daos_epoch_t* epoch, mfu_flist bflist) {
+static int daos_obj_list_oids(daos_args_t* da, mfu_flist bflist) {
     /* List objects in src container to be copied to 
      * destination container */
     static const int     OID_ARR_SIZE = 50;
@@ -1177,7 +1191,7 @@ static int daos_obj_list_oids(daos_args_t* da, daos_epoch_t* epoch, mfu_flist bf
     int                  rc = 0;
 
     /* create snapshot to pass to object iterator table */
-    rc = daos_cont_create_snap_opt(da->src_coh, epoch, NULL,
+    rc = daos_cont_create_snap_opt(da->src_coh, &da->epc, NULL,
     				   DAOS_SNAP_OPT_CR | DAOS_SNAP_OPT_OIT,
 				   NULL);
     if (rc != 0) {
@@ -1187,7 +1201,7 @@ static int daos_obj_list_oids(daos_args_t* da, daos_epoch_t* epoch, mfu_flist bf
     }
 
     /* open object iterator table */
-    rc = daos_oit_open(da->src_coh, *epoch, &toh, NULL);
+    rc = daos_oit_open(da->src_coh, da->epc, &toh, NULL);
     if (rc != 0) {
         MFU_LOG(MFU_LOG_ERR, "DAOS failed to open oit: ", MFU_ERRF,
                 MFU_ERRP(-MFU_ERR_DAOS));
@@ -1229,7 +1243,6 @@ static int daos_obj_list_oids(daos_args_t* da, daos_epoch_t* epoch, mfu_flist bf
 
 int mfu_flist_walk_daos(
     daos_args_t* da,
-    daos_epoch_t* epoch,
     mfu_flist flist)
 {
     /* assume we'll succeed */
@@ -1241,7 +1254,7 @@ int mfu_flist_walk_daos(
 
     /* have rank 0 do the work of listing the objects */
     if (rank == 0) {
-        rc = daos_obj_list_oids(da, epoch, flist);
+        rc = daos_obj_list_oids(da, flist);
         if (rc != 0) {
             MFU_LOG(MFU_LOG_ERR, "DAOS failed to list oids: ",
                 MFU_ERRF, MFU_ERRP(-MFU_ERR_DAOS));

src/common/mfu_daos.h

@@ -34,6 +34,7 @@ typedef struct {
     char* src_path;        /* allocated src path */
     char* dst_path;        /* allocated dst path */
     daos_api_t api;        /* API to use */
+    daos_epoch_t epc;      /* src container epoch */
 } daos_args_t;
 
 /* Return a newly allocated daos_args_t structure.
@@ -48,6 +49,11 @@ int daos_parse_api_str(
     const char* api_str,
     daos_api_t* api);
 
+/* Parse a string representation of the epoch */
+int daos_parse_epc_str(
+    const char* epc_str,
+    daos_epoch_t* epc);
+
 /* Setup DAOS arguments.
  * Connect to pools.
  * Open containers.
@@ -74,7 +80,6 @@ int daos_cleanup(
 /* walk objects in daos and insert to given flist */
 int mfu_flist_walk_daos(
     daos_args_t* da,
-    daos_epoch_t* epoch,
     mfu_flist flist
 );
 

src/dcp/dcp.c

@@ -469,8 +469,7 @@ int main(int argc, char** argv)
     else {
         /* take a snapshot and walk container to get list of objects,
          * returns epoch number of snapshot */
-        daos_epoch_t epoch;
-        int tmp_rc = mfu_flist_walk_daos(daos_args, &epoch, flist);
+        int tmp_rc = mfu_flist_walk_daos(daos_args, flist);
         if (tmp_rc != 0) {
             rc = 1;
         }
@@ -491,10 +490,11 @@ int main(int argc, char** argv)
         }
 
         /* destroy snapshot after copy */
+        /* TODO consider moving this into mfu_flist_copy_daos */
         if (rank == 0) {
             daos_epoch_range_t epr;
-            epr.epr_lo = epoch;
-            epr.epr_hi = epoch;
+            epr.epr_lo = daos_args->epc;
+            epr.epr_hi = daos_args->epc;
             rc = daos_cont_destroy_snap(daos_args->src_coh, epr, NULL);
             if (rc != 0) {
                 MFU_LOG(MFU_LOG_ERR, "DAOS destroy snapshot failed: ", MFU_ERRF,