ITS#7961,#7987 Re-fix txn init.

More fallout from 4d02c741b120786df1b87ee9ed49c1d3f9bc7522:
Don't modify another thread's write txn. Reinit me_txn0 fully.

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index b7b2ab3c06aa810e8461319f22fd42024ddea558..3b82277a56ba4d91af600a56e9d6b7ad085caaa2 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -2584,6 +2584,10 @@ mdb_txn_renew0(MDB_txn *txn)
                if (txn->mt_txnid == mdb_debug_start)
                        mdb_debug = 1;
 #endif
+               txn->mt_flags = 0;
+               txn->mt_child = NULL;
+               txn->mt_loose_pgs = NULL;
+               txn->mt_loose_count = 0;
                txn->mt_dirty_room = MDB_IDL_UM_MAX;
                txn->mt_u.dirty_list = env->me_dirty_list;
                txn->mt_u.dirty_list[0].mid = 0;
@@ -2669,7 +2673,6 @@ mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
        if (!(flags & MDB_RDONLY)) {
                if (!parent) {
                        txn = env->me_txn0;     /* just reuse preallocated write txn */
-                       txn->mt_flags = 0;
                        goto ok;
                }
                /* child txns use own copy of cursors */
@@ -2820,6 +2823,8 @@ mdb_txn_reset0(MDB_txn *txn, const char *act)
                env->me_pghead = NULL;
                env->me_pglast = 0;
 
+               mdb_cursors_close(txn, 0);
+
                if (!(env->me_flags & MDB_WRITEMAP)) {
                        mdb_dlist_free(txn);
                }
@@ -2832,19 +2837,15 @@ mdb_txn_reset0(MDB_txn *txn, const char *act)
                        /* The writer mutex was locked in mdb_txn_begin. */
                        if (env->me_txns)
                                UNLOCK_MUTEX(MDB_MUTEX(env, w));
-               }
-
-               mdb_cursors_close(txn, 0);
-
-               mdb_midl_free(pghead);
-
-               if (txn->mt_parent) {
+               } else {
                        txn->mt_parent->mt_child = NULL;
                        env->me_pgstate = ((MDB_ntxn *)txn)->mnt_pgstate;
                        mdb_midl_free(txn->mt_free_pgs);
                        mdb_midl_free(txn->mt_spill_pgs);
                        free(txn->mt_u.dirty_list);
                }
+
+               mdb_midl_free(pghead);
        }
 }