modules/kvs: avoid extra treeobj_encode in store_cache

Problem: treeobj that is to be stored in the cache is encoded
once to calculate its hash, and again to be stored in raw
form.

Just encode the treeobj in raw form, then calculate its
hash and store it raw.

src/modules/kvs/commit.c

@@ -206,7 +206,7 @@ static int store_cache (commit_t *c, int current_epoch, json_t *o,
                         bool is_raw, href_t ref, struct cache_entry **hpp)
 {
     struct cache_entry *hp;
-    int saved_errno, rc = -1;
+    int saved_errno, rc;
     const char *xdata;
     char *data = NULL;
     int xlen, len;
@@ -231,40 +231,38 @@ static int store_cache (commit_t *c, int current_epoch, json_t *o,
             free (data);
             data = NULL;
         }
-        blobref_hash (c->cm->hash_name, data, len, ref, sizeof (href_t));
     }
     else {
-        if (treeobj_hash (c->cm->hash_name, o, ref, sizeof (href_t)) < 0) {
-            flux_log_error (c->cm->h, "treeobj_hash");
+        if (treeobj_validate (o) < 0 || !(data = treeobj_encode (o))) {
+            flux_log_error (c->cm->h, "%s: treeobj_encode", __FUNCTION__);
             goto error;
         }
+        len = strlen (data);
+    }
+    if (blobref_hash (c->cm->hash_name, data, len, ref, sizeof (href_t)) < 0) {
+        flux_log_error (c->cm->h, "%s: blobref_hash", __FUNCTION__);
+        goto error;
     }
     if (!(hp = cache_lookup (c->cm->cache, ref, current_epoch))) {
-        if (!(hp = cache_entry_create ()))
+        if (!(hp = cache_entry_create ())) {
+            flux_log_error (c->cm->h, "%s: cache_entry_create", __FUNCTION__);
             goto error;
+        }
         cache_insert (c->cm->cache, ref, hp);
     }
     if (cache_entry_get_valid (hp)) {
         c->cm->noop_stores++;
         rc = 0;
-    } else {
-        if (is_raw) {
-            if (cache_entry_set_raw (hp, data, len) < 0) {
-                int ret;
-                ret = cache_remove_entry (c->cm->cache, ref);
-                assert (ret == 1);
-                goto error;
-            }
-        }
-        else {
-            if (cache_entry_set_treeobj (hp, o) < 0) {
-                int ret;
-                ret = cache_remove_entry (c->cm->cache, ref);
-                assert (ret == 1);
-                goto error;
-            }
+    }
+    else {
+        if (cache_entry_set_raw (hp, data, len) < 0) {
+            int ret;
+            ret = cache_remove_entry (c->cm->cache, ref);
+            assert (ret == 1);
+            goto error;
         }
         if (cache_entry_set_dirty (hp, true) < 0) {
+            flux_log_error (c->cm->h, "%s: cache_entry_set_dirty",__FUNCTION__);
             int ret;
             ret = cache_remove_entry (c->cm->cache, ref);
             assert (ret == 1);
@@ -280,7 +278,7 @@ static int store_cache (commit_t *c, int current_epoch, json_t *o,
     saved_errno = errno;
     free (data);
     errno = saved_errno;
-    return rc;
+    return -1;
 }
 
 /* Store DIRVAL objects, converting them to DIRREFs.