tdb: Add a non-blocking version of tdb_transaction_start

4 files changed, 22 insertions, 7 deletions

diff --git a/lib/tdb/common/lock.c b/lib/tdb/common/lock.c
index 0b130a8935..285b7a34c3 100644
--- a/lib/tdb/common/lock.c
+++ b/lib/tdb/common/lock.c
@@ -472,9 +472,10 @@ int tdb_unlock(struct tdb_context *tdb, int list, int ltype)
 /*
   get the transaction lock
  */
-int tdb_transaction_lock(struct tdb_context *tdb, int ltype)
+int tdb_transaction_lock(struct tdb_context *tdb, int ltype,
+			 enum tdb_lock_flags lockflags)
 {
-	return tdb_nest_lock(tdb, TRANSACTION_LOCK, ltype, TDB_LOCK_WAIT);
+	return tdb_nest_lock(tdb, TRANSACTION_LOCK, ltype, lockflags);
 }
 
 /*
diff --git a/lib/tdb/common/tdb_private.h b/lib/tdb/common/tdb_private.h
index 4e979ac748..b23b76a416 100644
--- a/lib/tdb/common/tdb_private.h
+++ b/lib/tdb/common/tdb_private.h
@@ -232,7 +232,8 @@ 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);
 void tdb_release_transaction_locks(struct tdb_context *tdb);
-int tdb_transaction_lock(struct tdb_context *tdb, int ltype);
+int tdb_transaction_lock(struct tdb_context *tdb, int ltype,
+			 enum tdb_lock_flags lockflags);
 int tdb_transaction_unlock(struct tdb_context *tdb, int ltype);
 int tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
 		       enum tdb_lock_flags flags, bool upgradable);
diff --git a/lib/tdb/common/transaction.c b/lib/tdb/common/transaction.c
index 504d0f681a..304a03fa38 100644
--- a/lib/tdb/common/transaction.c
+++ b/lib/tdb/common/transaction.c
@@ -421,7 +421,8 @@ static const struct tdb_methods transaction_methods = {
   start a tdb transaction. No token is returned, as only a single
   transaction is allowed to be pending per tdb_context
 */
-int tdb_transaction_start(struct tdb_context *tdb)
+static int _tdb_transaction_start(struct tdb_context *tdb,
+				  enum tdb_lock_flags lockflags)
 {
 	/* some sanity checks */
 	if (tdb->read_only || (tdb->flags & TDB_INTERNAL) || tdb->traverse_read) {
@@ -473,9 +474,12 @@ int tdb_transaction_start(struct tdb_context *tdb)
 	/* get the transaction write lock. This is a blocking lock. As
 	   discussed with Volker, there are a number of ways we could
 	   make this async, which we will probably do in the future */
-	if (tdb_transaction_lock(tdb, F_WRLCK) == -1) {
+	if (tdb_transaction_lock(tdb, F_WRLCK, lockflags) == -1) {
 		SAFE_FREE(tdb->transaction->blocks);
 		SAFE_FREE(tdb->transaction);
+		if ((lockflags & TDB_LOCK_WAIT) == 0) {
+			tdb->ecode = TDB_ERR_NOLOCK;
+		}
 		return -1;
 	}
 
@@ -525,6 +529,15 @@ fail_allrecord_lock:
 	return -1;
 }
 
+int tdb_transaction_start(struct tdb_context *tdb)
+{
+	return _tdb_transaction_start(tdb, TDB_LOCK_WAIT);
+}
+
+int tdb_transaction_start_nonblock(struct tdb_context *tdb)
+{
+	return _tdb_transaction_start(tdb, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
+}
 
 /*
   sync to disk
diff --git a/lib/tdb/common/traverse.c b/lib/tdb/common/traverse.c
index baaf58ae87..d77086a79a 100644
--- a/lib/tdb/common/traverse.c
+++ b/lib/tdb/common/traverse.c
@@ -220,7 +220,7 @@ int tdb_traverse_read(struct tdb_context *tdb,
 
 	/* we need to get a read lock on the transaction lock here to
 	   cope with the lock ordering semantics of solaris10 */
-	if (tdb_transaction_lock(tdb, F_RDLCK)) {
+	if (tdb_transaction_lock(tdb, F_RDLCK, TDB_LOCK_WAIT)) {
 		return -1;
 	}
 
@@ -251,7 +251,7 @@ int tdb_traverse(struct tdb_context *tdb,
 		return tdb_traverse_read(tdb, fn, private_data);
 	}
 
-	if (tdb_transaction_lock(tdb, F_WRLCK)) {
+	if (tdb_transaction_lock(tdb, F_WRLCK, TDB_LOCK_WAIT)) {
 		return -1;
 	}