bool ctdb_readrecordlock_async(struct ctdb_db *ctdb_db, TDB_DATA key,
ctdb_rrl_callback_t callback, void *cbdata);
+/**
+ * ctdb_readonlyrecordlock_async - read and lock a record for read-only access
+ * @ctdb_db: the database handle from ctdb_attachdb/ctdb_attachdb_recv.
+ * @key: the key of the record to lock.
+ * @callback: the callback once the record is locked (typesafe).
+ * @cbdata: the argument to callback()
+ *
+ * This returns true on success. Commonly, we can obtain the record
+ * immediately and so the callback will be invoked. Otherwise a request
+ * will be queued to ctdbd for the record.
+ *
+ * If failure is immediate, false is returned. Otherwise, the callback
+ * may receive a NULL lock arg to indicate asynchronous failure.
+ */
+bool ctdb_readonlyrecordlock_async(struct ctdb_db *ctdb_db, TDB_DATA key,
+ ctdb_rrl_callback_t callback, void *cbdata);
+
+
/**
* ctdb_writerecord - write a locked record in a TDB
* @ctdb_db: the database handle from ctdb_attachdb/ctdb_attachdb_recv.
core of libctdb
Copyright (C) Rusty Russell 2010
+ Copyright (C) Ronnie Sahlberg 2011
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
/* Remove type-safety macros. */
#undef ctdb_attachdb_send
#undef ctdb_readrecordlock_async
+#undef ctdb_readonlyrecordlock_async
#undef ctdb_connect
struct ctdb_lock {
struct ctdb_db *ctdb_db;
TDB_DATA key;
+ /* Is this a request for read-only lock ? */
+ bool readonly;
+
/* This will always be set by the time user sees this. */
unsigned long held_magic;
struct ctdb_ltdb_header *hdr;
}
hdr = ctdb_local_fetch(lock->ctdb_db->tdb, lock->key, data);
+ if (hdr && lock->readonly && (hdr->flags & CTDB_REC_RO_HAVE_READONLY) ) {
+ DEBUG(lock->ctdb_db->ctdb, LOG_DEBUG,
+ "ctdb_readrecordlock_async: got local lock for ro");
+ lock->held_magic = lock_magic(lock);
+ lock->hdr = hdr;
+ add_lock(lock->ctdb_db->ctdb, lock);
+ return true;
+ }
if (hdr && hdr->dmaster == lock->ctdb_db->ctdb->pnn) {
DEBUG(lock->ctdb_db->ctdb, LOG_DEBUG,
"ctdb_readrecordlock_async: got local lock");
struct ctdb_reply_call *reply;
TDB_DATA data;
- /* OK, we've received reply to noop migration */
- reply = unpack_reply_call(req, CTDB_NULL_FUNC);
+ /* OK, we've received reply to fetch-with-header migration */
+ reply = unpack_reply_call(req, CTDB_FETCH_WITH_HEADER_FUNC);
if (!reply || reply->status != 0) {
if (reply) {
DEBUG(ctdb, LOG_ERR,
"ctdb_readrecordlock_async(async):"
- " NULL_FUNC returned %i", reply->status);
+ " FETCH_WITH_HEADER_FUNC returned %i", reply->status);
}
lock->callback(lock->ctdb_db, NULL, tdb_null, private);
ctdb_request_free(req); /* Also frees lock. */
DLIST_ADD(ctdb->outq, req);
}
-bool
-ctdb_readrecordlock_async(struct ctdb_db *ctdb_db, TDB_DATA key,
- ctdb_rrl_callback_t callback, void *cbdata)
+static bool
+ctdb_readrecordlock_internal(struct ctdb_db *ctdb_db, TDB_DATA key,
+ bool readonly,
+ ctdb_rrl_callback_t callback, void *cbdata)
{
struct ctdb_request *req;
struct ctdb_lock *lock;
lock->ctdb_db = ctdb_db;
lock->hdr = NULL;
lock->held_magic = 0;
+ lock->readonly = readonly;
/* Fast path. */
if (try_readrecordlock(lock, &data)) {
io_elem_init_req_header(req->io, CTDB_REQ_CALL, CTDB_CURRENT_NODE,
new_reqid(ctdb_db->ctdb));
- req->hdr.call->flags = CTDB_IMMEDIATE_MIGRATION;
+ if (lock->readonly) {
+ req->hdr.call->flags = CTDB_WANT_READONLY;
+ } else {
+ req->hdr.call->flags = CTDB_IMMEDIATE_MIGRATION;
+ }
req->hdr.call->db_id = ctdb_db->id;
- req->hdr.call->callid = CTDB_NULL_FUNC;
+ req->hdr.call->callid = CTDB_FETCH_WITH_HEADER_FUNC;
req->hdr.call->hopcount = 0;
req->hdr.call->keylen = key.dsize;
req->hdr.call->calldatalen = 0;
return true;
}
+bool
+ctdb_readrecordlock_async(struct ctdb_db *ctdb_db, TDB_DATA key,
+ ctdb_rrl_callback_t callback, void *cbdata)
+{
+ return ctdb_readrecordlock_internal(ctdb_db, key,
+ false,
+ callback, cbdata);
+}
+
+bool
+ctdb_readonlyrecordlock_async(struct ctdb_db *ctdb_db, TDB_DATA key,
+ ctdb_rrl_callback_t callback, void *cbdata)
+{
+ return ctdb_readrecordlock_internal(ctdb_db, key,
+ true,
+ callback, cbdata);
+}
+
bool ctdb_writerecord(struct ctdb_db *ctdb_db,
struct ctdb_lock *lock, TDB_DATA data)
{