tdb: cleanup: split brlock and brunlock methods.

This is taken from the CCAN code base: rather than using tdb_brlock for
locking and unlocking, we split it into brlock and brunlock functions.

For extra debugging information, brunlock says what kind of lock it is
unlocking (even though fnctl locks don't need this).  This requires an
extra argument to tdb_transaction_unlock() so we know whether the
lock was upgraded to a write lock or not.

We also use a "flags" argument tdb_brlock:
1) TDB_LOCK_NOWAIT replaces lck_type = F_SETLK (vs F_SETLKW).
2) TDB_LOCK_MARK_ONLY replaces setting TDB_MARK_LOCK bit in ltype.
3) TDB_LOCK_PROBE replaces the "probe" argument.

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

1 files changed, 18 insertions, 4 deletions

diff --git a/lib/tdb/common/tdb_private.h b/lib/tdb/common/tdb_private.h
index 0e74b103b3..26d2cf55fa 100644
--- a/lib/tdb/common/tdb_private.h
+++ b/lib/tdb/common/tdb_private.h
@@ -163,6 +163,15 @@ struct tdb_traverse_lock {
 	int lock_rw;
 };
 
+enum tdb_lock_flags {
+	/* WAIT == F_SETLKW, NOWAIT == F_SETLK */
+	TDB_LOCK_NOWAIT = 0,
+	TDB_LOCK_WAIT = 1,
+	/* If set, don't log an error on failure. */
+	TDB_LOCK_PROBE = 2,
+	/* If set, don't actually lock at all. */
+	TDB_LOCK_MARK_ONLY = 4,
+};
 
 struct tdb_methods {
 	int (*tdb_read)(struct tdb_context *, tdb_off_t , void *, tdb_len_t , int );
@@ -170,7 +179,8 @@ struct tdb_methods {
 	void (*next_hash_chain)(struct tdb_context *, uint32_t *);
 	int (*tdb_oob)(struct tdb_context *, tdb_off_t , int );
 	int (*tdb_expand_file)(struct tdb_context *, tdb_off_t , tdb_off_t );
-	int (*tdb_brlock)(struct tdb_context *, tdb_off_t , int, int, int, size_t);
+	int (*brlock)(struct tdb_context *, int, tdb_off_t, size_t, enum tdb_lock_flags);
+	int (*brunlock)(struct tdb_context *, int, tdb_off_t, size_t);
 };
 
 struct tdb_context {
@@ -215,9 +225,13 @@ void tdb_mmap(struct tdb_context *tdb);
 int tdb_lock(struct tdb_context *tdb, int list, int ltype);
 int tdb_lock_nonblock(struct tdb_context *tdb, int list, int ltype);
 int tdb_unlock(struct tdb_context *tdb, int list, int ltype);
-int tdb_brlock(struct tdb_context *tdb, tdb_off_t offset, int rw_type, int lck_type, int probe, size_t len);
+int tdb_brlock(struct tdb_context *tdb,
+	       int rw_type, tdb_off_t offset, size_t len,
+	       enum tdb_lock_flags flags);
+int tdb_brunlock(struct tdb_context *tdb,
+		 int rw_type, tdb_off_t offset, size_t len);
 int tdb_transaction_lock(struct tdb_context *tdb, int ltype);
-int tdb_transaction_unlock(struct tdb_context *tdb);
+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);
 int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off);
 int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off);
@@ -230,7 +244,7 @@ int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 int tdb_lock_record(struct tdb_context *tdb, tdb_off_t off);
 int tdb_unlock_record(struct tdb_context *tdb, tdb_off_t off);
-int _tdb_transaction_cancel(struct tdb_context *tdb);
+int _tdb_transaction_cancel(struct tdb_context *tdb, int ltype);
 int tdb_rec_read(struct tdb_context *tdb, tdb_off_t offset, struct tdb_record *rec);
 int tdb_rec_write(struct tdb_context *tdb, tdb_off_t offset, struct tdb_record *rec);
 int tdb_do_delete(struct tdb_context *tdb, tdb_off_t rec_ptr, struct tdb_record *rec);