mon: fix mon_keyvaluedb application

In 42a6b0efe1a3269c8e6c10e89f92bc0f28923af2 I mistakenly thought that
create_or_open was the path taken for normal open (not during mkfs) and
made it assume a missing kv_type meant leveldb.  In reality, this is the
only path where mon_keyvaluedb is ever used (during mkfs), and
create_or_open is only called during mkfs.  The bug I was (probably?)
trying to fix was that regular open() did not write out a kv_type file
(with the assumption of leveldb) if it was missing.  As a result, the
previous fix was forcing all mons to be leveldb.

Fix this by reverting the create_or_open hunk (so that we express
mon_keyvaluedb on mkfs), and fixing the normal open path to write kv_type
if it is missing.  This effectively switches the mon back to rocksdb by
default (and allows teuthology to test both rocksdb and leveldb by setting
the option).

Signed-off-by: Sage Weil <sage@redhat.com>

diff --git a/src/mon/MonitorDBStore.h b/src/mon/MonitorDBStore.h
index e6732384c206613d48f31a4bb82677f2b93e7a68..707d635af557a01a91c4a5f694797e9d9f7dd017 100644 (file)
--- a/src/mon/MonitorDBStore.h
+++ b/src/mon/MonitorDBStore.h
@@ -629,9 +629,13 @@ class MonitorDBStore
   int open(ostream &out) {
     string kv_type;
     int r = read_meta("kv_backend", &kv_type);
-    if (r < 0 || kv_type.length() == 0)
+    if (r < 0 || kv_type.empty()) {
+      // assume old monitors that did not mark the type were leveldb.
       kv_type = "leveldb";
-
+      r = write_meta("kv_backend", kv_type);
+      if (r < 0)
+       return r;
+    }
     _open(kv_type);
     r = db->open(out);
     if (r < 0)
@@ -646,8 +650,7 @@ class MonitorDBStore
     string kv_type;
     int r = read_meta("kv_backend", &kv_type);
     if (r < 0) {
-      // assume old monitors that did not mark the type were leveldb.
-      kv_type = "leveldb";
+      kv_type = g_conf->mon_keyvaluedb;
       r = write_meta("kv_backend", kv_type);
       if (r < 0)
        return r;