r10408: now that we are using tdb transactions we don't need any additional

locking code in the ldb_tdb backend, except for a single read lock
during searches to ensure searches don't cross transaction boundaries

The tdb transactions code would map these extra locks to noops anyway
(as locking makes no sense inside a transaction), but the work in
setting up the locking keys still costs something, and it makes the
code needlessly complex
(This used to be commit 1b8d368a6771360fb0626127c02b3eb95f3eae59)

3 files changed, 36 insertions, 166 deletions

diff --git a/source4/lib/ldb/ldb_tdb/ldb_search.c b/source4/lib/ldb/ldb_tdb/ldb_search.c
index fc864ac2ea..83079eab81 100644
--- a/source4/lib/ldb/ldb_tdb/ldb_search.c
+++ b/source4/lib/ldb/ldb_tdb/ldb_search.c
@@ -242,6 +242,42 @@ int ltdb_search_dn1(struct ldb_module *module, const struct ldb_dn *dn, struct l
 	return 1;
 }
 
+/* the lock key for search locking. Note that this is not a DN, its
+   just an arbitrary key to give to tdb. Also note that as we and
+   using transactions for all write operations and transactions take
+   care of their own locks, we don't need to do any locking anywhere
+   other than in ldb_search() */
+#define LDBLOCK	"INT_LDBLOCK"
+
+/*
+  lock the database for read - use by ltdb_search
+*/
+static int ltdb_lock_read(struct ldb_module *module)
+{
+	struct ltdb_private *ltdb = module->private_data;
+	TDB_DATA key;
+
+	key.dptr = discard_const(LDBLOCK);
+	key.dsize = strlen(LDBLOCK);
+
+	return tdb_chainlock_read(ltdb->tdb, key);
+}
+
+/*
+  unlock the database after a ltdb_lock_read()
+*/
+static int ltdb_unlock_read(struct ldb_module *module)
+{
+	struct ltdb_private *ltdb = module->private_data;
+	TDB_DATA key;
+
+	key.dptr = discard_const(LDBLOCK);
+	key.dsize = strlen(LDBLOCK);
+
+	return tdb_chainunlock_read(ltdb->tdb, key);
+}
+
+
 
 /*
   search the database for a single simple dn
diff --git a/source4/lib/ldb/ldb_tdb/ldb_tdb.c b/source4/lib/ldb/ldb_tdb/ldb_tdb.c
index a2faaa805f..d8a03c3f55 100644
--- a/source4/lib/ldb/ldb_tdb/ldb_tdb.c
+++ b/source4/lib/ldb/ldb_tdb/ldb_tdb.c
@@ -41,9 +41,6 @@
 #include "ldb/include/ldb_private.h"
 #include "ldb/ldb_tdb/ldb_tdb.h"
 
-#define LDBLOCK	"@INT_LDBLOCK"
-
-
 /*
   form a TDB_DATA for a record key
   caller frees
@@ -96,141 +93,6 @@ failed:
 }
 
 /*
-  lock the database for write - currently a single lock is used
-*/
-static int ltdb_lock(struct ldb_module *module, const char *lockname)
-{
-	struct ltdb_private *ltdb = module->private_data;
-	struct ldb_dn *lock_dn;
-	char *ldn;
-	TDB_DATA key;
-	int ret;
-
-	if (lockname == NULL) {
-		return -1;
-	}
-
-	ldn = talloc_asprintf(module->ldb, "%s_%s", LDBLOCK, lockname);	
-	if (ldn == NULL) {
-		return -1;
-	}
-
-	lock_dn = ldb_dn_explode(module->ldb, ldn);
-	if (lock_dn == NULL) {
-		talloc_free(ldn);
-		return -1;
-	}
-	talloc_free(ldn);
-
-	key = ltdb_key(module, lock_dn);
-	if (!key.dptr) {
-		talloc_free(lock_dn);
-		return -1;
-	}
-
-	ret = tdb_chainlock(ltdb->tdb, key);
-
-	talloc_free(key.dptr);
-	talloc_free(lock_dn);
-
-	return ret;
-}
-
-/*
-  unlock the database after a ltdb_lock()
-*/
-static int ltdb_unlock(struct ldb_module *module, const char *lockname)
-{
-	struct ltdb_private *ltdb = module->private_data;
-	struct ldb_dn *lock_dn;
-	char *ldn;
-	TDB_DATA key;
-
-	if (lockname == NULL) {
-		return -1;
-	}
-
-	ldn = talloc_asprintf(module->ldb, "%s_%s", LDBLOCK, lockname);	
-	if (ldn == NULL) {
-		return -1;
-	}
-
-	lock_dn = ldb_dn_explode(module->ldb, ldn);
-	if (lock_dn == NULL) {
-		talloc_free(ldn);
-		return -1;
-	}
-	talloc_free(ldn);
-
-	key = ltdb_key(module, lock_dn);
-	if (!key.dptr) {
-		talloc_free(lock_dn);
-		return -1;
-	}
-
-	tdb_chainunlock(ltdb->tdb, key);
-
-	talloc_free(key.dptr);
-	talloc_free(lock_dn);
-
-	return 0;
-}
-
-
-/*
-  lock the database for read - use by ltdb_search
-*/
-int ltdb_lock_read(struct ldb_module *module)
-{
-	struct ltdb_private *ltdb = module->private_data;
-	TDB_DATA key;
-	struct ldb_dn *lock_dn;
-	int ret;
-
-	lock_dn = ldb_dn_explode(module, LDBLOCK);
-	if (lock_dn == NULL) {
-		return -1;
-	}
-
-	key = ltdb_key(module, lock_dn);
-	if (!key.dptr) {
-		talloc_free(lock_dn);
-		return -1;
-	}
-	talloc_free(lock_dn);
-
-	ret = tdb_chainlock_read(ltdb->tdb, key);
-	talloc_free(key.dptr);
-	return ret;
-}
-
-/*
-  unlock the database after a ltdb_lock_read()
-*/
-int ltdb_unlock_read(struct ldb_module *module)
-{
-	struct ltdb_private *ltdb = module->private_data;
-	struct ldb_dn *lock_dn;
-	TDB_DATA key;
-
-	lock_dn = ldb_dn_explode(module, LDBLOCK);
-	if (lock_dn == NULL) {
-		return -1;
-	}
-
-	key = ltdb_key(module, lock_dn);
-	if (!key.dptr) {
-		talloc_free(lock_dn);
-		return -1;
-	}
-	talloc_free(lock_dn);
-
-	tdb_chainunlock_read(ltdb->tdb, key);
-	talloc_free(key.dptr);
-	return 0;
-}
-
-/*
   check special dn's have valid attributes
   currently only @ATTRIBUTES is checked
 */
@@ -335,12 +197,7 @@ static int ltdb_add(struct ldb_module *module, const struct ldb_message *msg)
 		return ret;
 	}
 	
-	if (ltdb_lock(module, LDBLOCK) != 0) {
-		return LDB_ERR_OTHER;
-	}
-
 	if (ltdb_cache_load(module) != 0) {
-		ltdb_unlock(module, LDBLOCK);
 		return LDB_ERR_OTHER;
 	}
 
@@ -350,7 +207,6 @@ static int ltdb_add(struct ldb_module *module, const struct ldb_message *msg)
 		ltdb_modified(module, msg->dn);
 	}
 
-	ltdb_unlock(module, LDBLOCK);
 	return ret;
 }
 
@@ -386,10 +242,6 @@ static int ltdb_delete(struct ldb_module *module, const struct ldb_dn *dn)
 	struct ldb_message *msg = NULL;
 	int ret = LDB_ERR_OTHER;
 
-	if (ltdb_lock(module, LDBLOCK) != 0) {
-		return ret;
-	}
-
 	if (ltdb_cache_load(module) != 0) {
 		goto failed;
 	}
@@ -421,12 +273,10 @@ static int ltdb_delete(struct ldb_module *module, const struct ldb_dn *dn)
 		ret = LDB_ERR_OTHER;
 
 	talloc_free(msg);
-	ltdb_unlock(module, LDBLOCK);
 	return ret;
 
 failed:
 	talloc_free(msg);
-	ltdb_unlock(module, LDBLOCK);
 	return ret;
 }
 
@@ -749,12 +599,7 @@ static int ltdb_modify(struct ldb_module *module, const struct ldb_message *msg)
 		return ret;
 	}
 	
-	if (ltdb_lock(module, LDBLOCK) != 0) {
-		return -1;
-	}
-
 	if (ltdb_cache_load(module) != 0) {
-		ltdb_unlock(module, LDBLOCK);
 		return -1;
 	}
 
@@ -764,8 +609,6 @@ static int ltdb_modify(struct ldb_module *module, const struct ldb_message *msg)
 		ltdb_modified(module, msg->dn);
 	}
 
-	ltdb_unlock(module, LDBLOCK);
-
 	return ret;
 }
 
@@ -778,12 +621,7 @@ static int ltdb_rename(struct ldb_module *module, const struct ldb_dn *olddn, co
 	char *error_str;
 	int ret = LDB_ERR_OTHER;
 
-	if (ltdb_lock(module, LDBLOCK) != 0) {
-		return ret;
-	}
-
 	if (ltdb_cache_load(module) != 0) {
-		ltdb_unlock(module, LDBLOCK);
 		return ret;
 	}
 
@@ -821,13 +659,11 @@ static int ltdb_rename(struct ldb_module *module, const struct ldb_dn *olddn, co
 	ldb_set_errstring(module, error_str);
 
 	talloc_free(msg);
-	ltdb_unlock(module, LDBLOCK);
 
 	return ret;
 
 failed:
 	talloc_free(msg);
-	ltdb_unlock(module, LDBLOCK);
 	return ret;
 }
 
diff --git a/source4/lib/ldb/ldb_tdb/ldb_tdb.h b/source4/lib/ldb/ldb_tdb/ldb_tdb.h
index f1da556f99..c16db67e1f 100644
--- a/source4/lib/ldb/ldb_tdb/ldb_tdb.h
+++ b/source4/lib/ldb/ldb_tdb/ldb_tdb.h
@@ -96,8 +96,6 @@ struct TDB_DATA ltdb_key(struct ldb_module *module, const struct ldb_dn *dn);
 int ltdb_store(struct ldb_module *module, const struct ldb_message *msg, int flgs);
 int ltdb_delete_noindex(struct ldb_module *module, const struct ldb_dn *dn);
 int ltdb_modify_internal(struct ldb_module *module, const struct ldb_message *msg);
-int ltdb_lock_read(struct ldb_module *module);
-int ltdb_unlock_read(struct ldb_module *module);
 
 int ltdb_index_del_value(struct ldb_module *module, const char *dn, 
 			 struct ldb_message_element *el, int v_idx);