ITS#7635 simplify 9474c1a0b62cad57b62855d09a201670385caa80

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 84405e89634f0b31d319bd01c7246b46a8a3d5c1..0badbbbf690ba5f53586cce6ea7f32aa65ca6178 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -1743,7 +1743,6 @@ mdb_txn_renew0(MDB_txn *txn)
        unsigned int i;
        uint16_t x;
        int rc, new_notls = 0;
-       pgno_t lastpg2;
 
        /* Setup db info */
        txn->mt_numdbs = env->me_numdbs;
@@ -1790,13 +1789,11 @@ mdb_txn_renew0(MDB_txn *txn)
                        txn->mt_u.reader = r;
                }
                txn->mt_toggle = txn->mt_txnid & 1;
-               txn->mt_next_pgno = env->me_metas[txn->mt_toggle]->mm_last_pg+1;
        } else {
                LOCK_MUTEX_W(env);
 
                txn->mt_txnid = env->me_txns->mti_txnid;
                txn->mt_toggle = txn->mt_txnid & 1;
-               txn->mt_next_pgno = env->me_metas[txn->mt_toggle]->mm_last_pg+1;
                txn->mt_txnid++;
 #if MDB_DEBUG
                if (txn->mt_txnid == mdb_debug_start)
@@ -1812,17 +1809,10 @@ mdb_txn_renew0(MDB_txn *txn)
 
        /* Copy the DB info and flags */
        memcpy(txn->mt_dbs, env->me_metas[txn->mt_toggle]->mm_dbs, 2 * sizeof(MDB_db));
-       /* In a read txn, there is a data race here. Make sure our
-        * last_pg/next_pg are up to date.
-        */
-       lastpg2 = env->me_metas[txn->mt_toggle]->mm_last_pg+1;
-       if (lastpg2 != txn->mt_next_pgno) {
-               txn->mt_next_pgno = lastpg2;
-               /* When this situation occurs, the txnid will certainly also
-                * be out of date. But as noted before, we don't care about having
-                * up to date read txn IDs.
-                */
-       }
+
+       /* Moved to here to avoid a data race in read TXNs */
+       txn->mt_next_pgno = env->me_metas[txn->mt_toggle]->mm_last_pg+1;
+
        for (i=2; i<txn->mt_numdbs; i++) {
                x = env->me_dbflags[i];
                txn->mt_dbs[i].md_flags = x & PERSISTENT_FLAGS;