tdb: cleanup: tdb_have_extra_locks() helper

In many places we check whether locks are held: add a helper to do this.

The _tdb_lockall() case has already checked for the allrecord lock, so
the extra work done by tdb_have_extra_locks() is merely redundant.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

ccan/tdb/lock.c

@@ -474,8 +474,8 @@ static int _tdb_lockall(struct tdb_context *tdb, int ltype,
 		tdb->ecode = TDB_ERR_LOCK;
 		return -1;
 	}
-	
-	if (tdb->num_locks != 0) {
+
+	if (tdb_have_extra_locks(tdb)) {
 		/* can't combine global and chain locks */
 		tdb->ecode = TDB_ERR_LOCK;
 		return -1;
@@ -691,3 +691,14 @@ int tdb_unlock_record(struct tdb_context *tdb, tdb_off_t off)
 			count++;
 	return (count == 1 ? tdb->methods->brunlock(tdb, F_RDLCK, off, 1) : 0);
 }
+
+bool tdb_have_extra_locks(struct tdb_context *tdb)
+{
+	if (tdb->allrecord_lock.count) {
+		return true;
+	}
+	if (tdb->num_lockrecs) {
+		return true;
+	}
+	return false;
+}

ccan/tdb/open.c

@@ -461,7 +461,7 @@ static int tdb_reopen_internal(struct tdb_context *tdb, bool active_lock)
 		return 0; /* Nothing to do. */
 	}
 
-	if (tdb->num_locks != 0 || tdb->allrecord_lock.count) {
+	if (tdb_have_extra_locks(tdb)) {
 		TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed with locks held\n"));
 		goto fail;
 	}

ccan/tdb/tdb_private.h

@@ -266,6 +266,7 @@ int tdb_brlock(struct tdb_context *tdb,
 	       enum tdb_lock_flags flags);
 int tdb_brunlock(struct tdb_context *tdb,
 		 int rw_type, tdb_off_t offset, size_t len);
+bool tdb_have_extra_locks(struct tdb_context *tdb);
 int tdb_transaction_lock(struct tdb_context *tdb, int ltype);
 int tdb_transaction_unlock(struct tdb_context *tdb, int ltype);
 int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len);

ccan/tdb/transaction.c

@@ -564,7 +564,7 @@ int tdb_transaction_start(struct tdb_context *tdb)
 		return 0;
 	}
 
-	if (tdb->num_locks != 0 || tdb->allrecord_lock.count) {
+	if (tdb_have_extra_locks(tdb)) {
 		/* the caller must not have any locks when starting a
 		   transaction as otherwise we'll be screwed by lack
 		   of nested locks in posix */
@@ -944,7 +944,7 @@ static int _tdb_transaction_prepare_commit(struct tdb_context *tdb)
 	
 	/* if there are any locks pending then the caller has not
 	   nested their locks properly, so fail the transaction */
-	if (tdb->num_locks || tdb->allrecord_lock.count) {
+	if (tdb_have_extra_locks(tdb)) {
 		tdb->ecode = TDB_ERR_LOCK;
 		TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: locks pending on commit\n"));
 		_tdb_transaction_cancel(tdb, F_RDLCK);