More copyfd2 tweaks

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index d64c954990bef66080248a21109d2fa5af27ba98..6997ae9583056203c3f79502126260ab5cf7cb18 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -8087,7 +8087,6 @@ again:
                                break;
                        }
                }
-               my->mc_wlen[toggle] = wsize;
                if (rc) {
                        my->mc_status = rc;
                        pthread_mutex_unlock(&my->mc_mutex[toggle]);
@@ -8100,6 +8099,7 @@ again:
                        my->mc_olen[toggle] = 0;
                        goto again;
                }
+               my->mc_wlen[toggle] = 0;
                toggle ^= 1;
        }
        return (THREAD_RET)0;
@@ -8117,8 +8117,6 @@ mdb_env_cthr_toggle(mdb_copy *my)
                pthread_mutex_unlock(&my->mc_mutex[toggle]);
                return my->mc_status;
        }
-       my->mc_wlen[toggle] = 0;
-       my->mc_olen[toggle] = 0;
        my->mc_toggle = toggle;
        return 0;
 }
@@ -8134,6 +8132,10 @@ mdb_env_cwalk(mdb_copy *my, pgno_t *pg, int flags)
        int rc, toggle;
        unsigned int i;
 
+       /* Empty DB, nothing to do */
+       if (*pg == P_INVALID)
+               return MDB_SUCCESS;
+
        mc.mc_snum = 1;
        mc.mc_top = 0;
        mc.mc_txn = txn;
@@ -8307,6 +8309,7 @@ mdb_env_copyfd2(MDB_env *env, HANDLE fd)
        my.mc_env = env;
        my.mc_fd = fd;
        pthread_mutex_lock(&my.mc_mutex[0]);
+       THREAD_CREATE(thr, mdb_env_copythr, &my);
 
        /* Do the lock/unlock of the reader mutex before starting the
         * write txn.  Otherwise other read txns could block writers.
@@ -8365,7 +8368,6 @@ mdb_env_copyfd2(MDB_env *env, HANDLE fd)
        }
        my.mc_wlen[0] = env->me_psize * 2;
        my.mc_txn = txn;
-       THREAD_CREATE(thr, mdb_env_copythr, &my);
        rc = mdb_env_cwalk(&my, &txn->mt_dbs[1].md_root, 0);
        if (rc == MDB_SUCCESS && my.mc_wlen[my.mc_toggle])
                rc = mdb_env_cthr_toggle(&my);