1 files changed, 95 insertions, 0 deletions
diff --git a/db/lock/lock_failchk.c b/db/lock/lock_failchk.c
new file mode 100644
index 000000000..55f729694
--- /dev/null
+++ b/db/lock/lock_failchk.c
@@ -0,0 +1,95 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 2005-2006
+ *	Oracle Corporation.  All rights reserved.
+ *
+ * $Id: lock_failchk.c,v 12.9 2006/08/24 14:46:11 bostic Exp $
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/lock.h"
+#include "dbinc/txn.h"
+
+/*
+ * __lock_failchk --
+ *	Check for locks held by dead threads of control.
+ *
+ * PUBLIC: int __lock_failchk __P((DB_ENV *));
+ */
+int
+__lock_failchk(dbenv)
+	DB_ENV *dbenv;
+{
+	DB_LOCKER *lip;
+	DB_LOCKREGION *lrp;
+	DB_LOCKREQ request;
+	DB_LOCKTAB *lt;
+	u_int32_t i;
+	int ret;
+	char buf[DB_THREADID_STRLEN];
+
+	lt = dbenv->lk_handle;
+	lrp = lt->reginfo.primary;
+
+retry:	LOCK_SYSTEM_LOCK(dbenv);
+
+	ret = 0;
+	for (i = 0; i < lrp->locker_t_size; i++)
+		SH_TAILQ_FOREACH(lip, &lt->locker_tab[i], links, __db_locker) {
+			/*
+			 * If the locker is transactional, we can ignore it;
+			 * __txn_failchk aborts any transactions the locker
+			 * is involved in.
+			 */
+			if (lip->id >= TXN_MINIMUM)
+				continue;
+
+			/* If the locker is still alive, it's not a problem. */
+			if (dbenv->is_alive(dbenv, lip->pid, lip->tid, 0))
+				continue;
+
+			/*
+			 * We can only deal with read locks.  If the locker
+			 * holds write locks we have to assume a Berkeley DB
+			 * operation was interrupted with only 1-of-N pages
+			 * modified.
+			 */
+			if (lip->nwrites != 0) {
+				ret = __db_failed(dbenv,
+				     "locker has write locks",
+				     lip->pid, lip->tid);
+				break;
+			}
+
+			/*
+			 * Discard the locker and its read locks.
+			 */
+			__db_msg(dbenv, "Freeing locks for locker %#lx: %s",
+			    (u_long)lip->id, dbenv->thread_id_string(
+			    dbenv, lip->pid, lip->tid, buf));
+			LOCK_SYSTEM_UNLOCK(dbenv);
+			memset(&request, 0, sizeof(request));
+			request.op = DB_LOCK_PUT_ALL;
+			if ((ret = __lock_vec(
+			    dbenv, lip->id, 0, &request, 1, NULL)) != 0)
+				return (ret);
+
+			/*
+			 * This locker is most likely referenced by a cursor
+			 * which is owned by a dead thread.  Normally the
+			 * cursor would be available for other threads
+			 * but we assume the dead thread will never release
+			 * it.
+			 */
+			if ((ret = __lock_freefamilylocker(lt, lip->id)) != 0)
+				return (ret);
+			goto retry;
+		}
+
+	LOCK_SYSTEM_UNLOCK(dbenv);
+
+	return (ret);
+}