refs #5153 minor cleanups from review

git-svn-id: file:///svn/toku/tokudb@45058 c7de825b-a66e-492c-adef-691d508d4ae1

ft/txn.c

@@ -519,9 +519,9 @@ toku_txn_is_read_only(TOKUTXN txn) {
     if (!txn->begin_was_logged) {
         // Did no work.
         invariant(txn->roll_info.num_rollentries == 0);
-        // Was not prepared.
         invariant(txn->do_fsync_lsn.lsn == ZERO_LSN.lsn);
         invariant(toku_omt_size(txn->open_fts) == 0);
+        invariant(txn->num_pin==0);
         return true;
     }
     return false;

ft/txn_manager.c

@@ -773,10 +773,8 @@ static void invalidate_xa_xid (TOKU_XA_XID *xid) {
 }
 
 void toku_txn_manager_note_abort_txn(TXN_MANAGER txn_manager, TOKUTXN txn) {
-    if (!txn->begin_was_logged) {
-        //Read only transaction
+    if (toku_txn_is_read_only(txn)) {
         invariant(txn->state==TOKUTXN_LIVE);
-        invariant(txn->num_pin==0);
         txn->state = TOKUTXN_ABORTING;
         goto done;
     }
@@ -802,10 +800,8 @@ void toku_txn_manager_note_abort_txn(TXN_MANAGER txn_manager, TOKUTXN txn) {
 }
 
 void toku_txn_manager_note_commit_txn(TXN_MANAGER txn_manager, TOKUTXN txn) {
-    if (!txn->begin_was_logged) {
-        //Read only transaction
+    if (toku_txn_is_read_only(txn)) {
         invariant(txn->state==TOKUTXN_LIVE);
-        invariant(txn->num_pin==0);
         txn->state = TOKUTXN_COMMITTING;
         goto done;
     }

src/ydb-internal.h

@@ -68,7 +68,7 @@ struct __toku_db_env_internal {
     TOKULOGGER logger;
     toku_ltm* ltm;
 
-    int open_txns;                                      // Number of open transactions
+    int32_t open_txns;                                      // Number of open transactions
     DB *directory;                                      // Maps dnames to inames
     DB *persistent_environment;                         // Stores environment settings, can be used for upgrade
     OMT open_dbs;                                       // Stores open db handles, sorted first by dname and then by numerical value of pointer to the db (arbitrarily assigned memory location)

src/ydb_txn.c

@@ -47,8 +47,8 @@ toku_txn_release_locks(DB_TXN* txn) {
 
 static void
 toku_txn_destroy(DB_TXN *txn) {
-    (void) __sync_fetch_and_sub(&txn->mgrp->i->open_txns, 1);
-    assert(txn->mgrp->i->open_txns>=0);
+    int32_t open_txns = __sync_sub_and_fetch(&txn->mgrp->i->open_txns, 1);
+    invariant(open-txns > 0);
     toku_txn_destroy_txn(db_txn_struct_i(txn)->tokutxn);
     toku_mutex_destroy(&db_txn_struct_i(txn)->txn_mutex);
 #if !TOKUDB_NATIVE_H