tdb2: implement tdb_chainlock_read/tdb_chainunlock_read.

[ccan] / ccan / tdb2 / hash.c

diff --git a/ccan/tdb2/hash.c b/ccan/tdb2/hash.c
index 8bda587df88787ebed4d195ca8c57e4f909f3ed1..2b997008f7782961b370439488a570642be452eb 100644 (file)
--- a/ccan/tdb2/hash.c
+++ b/ccan/tdb2/hash.c
@@ -875,3 +875,24 @@ void tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key)
        tdb_trace_1rec(tdb, "tdb_chainunlock", key);
        tdb_unlock_hashes(tdb, lockstart, locksize, F_WRLCK);
 }
+
+enum TDB_ERROR tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key)
+{
+       return tdb->last_error = chainlock(tdb, &key, F_RDLCK, TDB_LOCK_WAIT,
+                                          "tdb_chainlock_read");
+}
+
+void tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key)
+{
+       uint64_t h = tdb_hash(tdb, key.dptr, key.dsize);
+       tdb_off_t lockstart, locksize;
+       unsigned int group, gbits;
+
+       gbits = TDB_TOPLEVEL_HASH_BITS - TDB_HASH_GROUP_BITS;
+       group = bits_from(h, 64 - gbits, gbits);
+
+       lockstart = hlock_range(group, &locksize);
+
+       tdb_trace_1rec(tdb, "tdb_chainunlock_read", key);
+       tdb_unlock_hashes(tdb, lockstart, locksize, F_RDLCK);
+}