From fb674c1cf58f19ddc0ff2ead443121d2c8359dd5 Mon Sep 17 00:00:00 2001 From: Howard Chu Date: Mon, 1 Jul 2013 14:53:29 -0700 Subject: [PATCH] ITS#7635 simplify 9474c1a0b62cad57b62855d09a201670385caa80 --- libraries/liblmdb/mdb.c | 18 ++++-------------- 1 file changed, 4 insertions(+), 14 deletions(-) diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c index 84405e8963..0badbbbf69 100644 --- 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mt_next_pgno = lastpg2; - /* When this situation occurs, the txnid will certainly also - * be out of date.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; imt_numdbs; i++) { x = env->me_dbflags[i]; txn->mt_dbs[i].md_flags = x & PERSISTENT_FLAGS; -- 2.39.5