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 9ebc1fe260e0e126c32a711c3deaa34c5d052bb6..2b997008f7782961b370439488a570642be452eb 100644 (file)
--- a/ccan/tdb2/hash.c
+++ b/ccan/tdb2/hash.c
@@ -857,10 +857,11 @@ static enum TDB_ERROR chainlock(struct tdb_context *tdb, const TDB_DATA *key,
    contention - it cannot guarantee how many records will be locked */
 enum TDB_ERROR tdb_chainlock(struct tdb_context *tdb, TDB_DATA key)
 {
-       return chainlock(tdb, &key, F_WRLCK, TDB_LOCK_WAIT, "tdb_chainlock");
+       return tdb->last_error = chainlock(tdb, &key, F_WRLCK, TDB_LOCK_WAIT,
+                                          "tdb_chainlock");
 }
 
-enum TDB_ERROR tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key)
+void tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key)
 {
        uint64_t h = tdb_hash(tdb, key.dptr, key.dsize);
        tdb_off_t lockstart, locksize;
@@ -872,5 +873,26 @@ enum TDB_ERROR tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key)
        lockstart = hlock_range(group, &locksize);
 
        tdb_trace_1rec(tdb, "tdb_chainunlock", key);
-       return tdb_unlock_hashes(tdb, lockstart, locksize, F_WRLCK);
+       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);
 }