1 files changed, 372 insertions, 0 deletions

diff --git a/ctdb/server/ctdb_update_record.c b/ctdb/server/ctdb_update_record.c
new file mode 100644
index 0000000..405499c
--- /dev/null
+++ b/ctdb/server/ctdb_update_record.c
@@ -0,0 +1,372 @@
+/* 
+   implementation of the update record control
+
+   Copyright (C) Andrew Tridgell  2007
+   Copyright (C) Ronnie Sahlberg  2007
+
+   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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "replace.h"
+#include "system/network.h"
+#include "system/time.h"
+
+#include <talloc.h>
+#include <tevent.h>
+
+#include "lib/tdb_wrap/tdb_wrap.h"
+#include "lib/util/debug.h"
+#include "lib/util/samba_util.h"
+#include "lib/util/sys_rw.h"
+#include "lib/util/util_process.h"
+
+#include "ctdb_private.h"
+#include "ctdb_client.h"
+
+#include "common/system.h"
+#include "common/common.h"
+#include "common/logging.h"
+
+struct ctdb_persistent_write_state {
+	struct ctdb_db_context *ctdb_db;
+	struct ctdb_marshall_buffer *m;
+	struct ctdb_req_control_old *c;
+	uint32_t flags;
+};
+
+/* don't create/update records that does not exist locally */
+#define UPDATE_FLAGS_REPLACE_ONLY	1
+
+/*
+  called from a child process to write the data
+ */
+static int ctdb_persistent_store(struct ctdb_persistent_write_state *state)
+{
+	unsigned int i;
+	int ret;
+	struct ctdb_rec_data_old *rec = NULL;
+	struct ctdb_marshall_buffer *m = state->m;
+
+	ret = tdb_transaction_start(state->ctdb_db->ltdb->tdb);
+	if (ret == -1) {
+		DEBUG(DEBUG_ERR,("Failed to start transaction for db_id 0x%08x in ctdb_persistent_store\n",
+				 state->ctdb_db->db_id));
+		return -1;
+	}
+
+	for (i=0;i<m->count;i++) {
+		struct ctdb_ltdb_header oldheader;
+		struct ctdb_ltdb_header header;
+		TDB_DATA key, data, olddata;
+		TALLOC_CTX *tmp_ctx = talloc_new(state);
+
+		rec = ctdb_marshall_loop_next(m, rec, NULL, &header, &key, &data);
+
+		if (rec == NULL) {
+			D_ERR("Failed to get next record %u for db_id 0x%08x "
+			      "in ctdb_persistent_store\n",
+			      i,
+			      state->ctdb_db->db_id);
+			talloc_free(tmp_ctx);
+			goto failed;
+		}
+
+		/* we must check if the record exists or not because
+		   ctdb_ltdb_fetch will unconditionally create a record
+		 */
+		if (state->flags & UPDATE_FLAGS_REPLACE_ONLY) {
+			TDB_DATA trec;
+			trec = tdb_fetch(state->ctdb_db->ltdb->tdb, key);
+			if (trec.dsize == 0) {
+				talloc_free(tmp_ctx);
+				continue;
+			}
+			free(trec.dptr);
+		}
+
+		/* fetch the old header and ensure the rsn is less than the new rsn */
+		ret = ctdb_ltdb_fetch(state->ctdb_db, key, &oldheader, tmp_ctx, &olddata);
+		if (ret != 0) {
+			DEBUG(DEBUG_ERR,("Failed to fetch old record for db_id 0x%08x in ctdb_persistent_store\n",
+					 state->ctdb_db->db_id));
+			talloc_free(tmp_ctx);
+			goto failed;
+		}
+
+		if (oldheader.rsn >= header.rsn &&
+		    (olddata.dsize != data.dsize ||
+		     memcmp(olddata.dptr, data.dptr, data.dsize) != 0)) {
+			DEBUG(DEBUG_CRIT,("existing header for db_id 0x%08x has larger RSN %llu than new RSN %llu in ctdb_persistent_store\n",
+					  state->ctdb_db->db_id,
+					  (unsigned long long)oldheader.rsn, (unsigned long long)header.rsn));
+			talloc_free(tmp_ctx);
+			goto failed;
+		}
+
+		talloc_free(tmp_ctx);
+
+		ret = ctdb_ltdb_store(state->ctdb_db, key, &header, data);
+		if (ret != 0) {
+			DEBUG(DEBUG_CRIT,("Failed to store record for db_id 0x%08x in ctdb_persistent_store\n",
+					  state->ctdb_db->db_id));
+			goto failed;
+		}
+	}
+
+	ret = tdb_transaction_commit(state->ctdb_db->ltdb->tdb);
+	if (ret == -1) {
+		DEBUG(DEBUG_ERR,("Failed to commit transaction for db_id 0x%08x in ctdb_persistent_store\n",
+				 state->ctdb_db->db_id));
+		return -1;
+	}
+
+	return 0;
+
+failed:
+	tdb_transaction_cancel(state->ctdb_db->ltdb->tdb);
+	return -1;
+}
+
+
+/*
+  called when we the child has completed the persistent write
+  on our behalf
+ */
+static void ctdb_persistent_write_callback(int status, void *private_data)
+{
+	struct ctdb_persistent_write_state *state = talloc_get_type(private_data,
+								   struct ctdb_persistent_write_state);
+
+
+	ctdb_request_control_reply(state->ctdb_db->ctdb, state->c, NULL, status, NULL);
+
+	talloc_free(state);
+}
+
+/*
+  called if our lockwait child times out
+ */
+static void ctdb_persistent_lock_timeout(struct tevent_context *ev,
+					 struct tevent_timer *te,
+					 struct timeval t, void *private_data)
+{
+	struct ctdb_persistent_write_state *state = talloc_get_type(private_data,
+								   struct ctdb_persistent_write_state);
+	ctdb_request_control_reply(state->ctdb_db->ctdb, state->c, NULL, -1, "timeout in ctdb_persistent_lock");
+	talloc_free(state);
+}
+
+struct childwrite_handle {
+	struct ctdb_context *ctdb;
+	struct ctdb_db_context *ctdb_db;
+	struct tevent_fd *fde;
+	int fd[2];
+	pid_t child;
+	void *private_data;
+	void (*callback)(int, void *);
+	struct timeval start_time;
+};
+
+static int childwrite_destructor(struct childwrite_handle *h)
+{
+	CTDB_DECREMENT_STAT(h->ctdb, pending_childwrite_calls);
+	ctdb_kill(h->ctdb, h->child, SIGKILL);
+	return 0;
+}
+
+/* called when the child process has finished writing the record to the
+   database
+*/
+static void childwrite_handler(struct tevent_context *ev,
+			       struct tevent_fd *fde,
+			       uint16_t flags, void *private_data)
+{
+	struct childwrite_handle *h = talloc_get_type(private_data,
+						     struct childwrite_handle);
+	void *p = h->private_data;
+	void (*callback)(int, void *) = h->callback;
+	pid_t child = h->child;
+	TALLOC_CTX *tmp_ctx = talloc_new(ev);
+	int ret;
+	char c;
+
+	CTDB_UPDATE_LATENCY(h->ctdb, h->ctdb_db, "persistent", childwrite_latency, h->start_time);
+	CTDB_DECREMENT_STAT(h->ctdb, pending_childwrite_calls);
+
+	/* the handle needs to go away when the context is gone - when
+	   the handle goes away this implicitly closes the pipe, which
+	   kills the child */
+	talloc_steal(tmp_ctx, h);
+
+	talloc_set_destructor(h, NULL);
+
+	ret = sys_read(h->fd[0], &c, 1);
+	if (ret < 1) {
+		DEBUG(DEBUG_ERR, (__location__ " Read returned %d. Childwrite failed\n", ret));
+		c = 1;
+	}
+
+	callback(c, p);
+
+	ctdb_kill(h->ctdb, child, SIGKILL);
+	talloc_free(tmp_ctx);
+}
+
+/* this creates a child process which will take out a tdb transaction
+   and write the record to the database.
+*/
+static struct childwrite_handle *ctdb_childwrite(
+				struct ctdb_db_context *ctdb_db,
+				void (*callback)(int, void *private_data),
+				struct ctdb_persistent_write_state *state)
+{
+	struct childwrite_handle *result;
+	int ret;
+	pid_t parent = getpid();
+
+	CTDB_INCREMENT_STAT(ctdb_db->ctdb, childwrite_calls);
+	CTDB_INCREMENT_STAT(ctdb_db->ctdb, pending_childwrite_calls);
+
+	if (!(result = talloc_zero(state, struct childwrite_handle))) {
+		CTDB_DECREMENT_STAT(ctdb_db->ctdb, pending_childwrite_calls);
+		return NULL;
+	}
+
+	ret = pipe(result->fd);
+
+	if (ret != 0) {
+		talloc_free(result);
+		CTDB_DECREMENT_STAT(ctdb_db->ctdb, pending_childwrite_calls);
+		return NULL;
+	}
+
+	result->child = ctdb_fork(ctdb_db->ctdb);
+
+	if (result->child == (pid_t)-1) {
+		close(result->fd[0]);
+		close(result->fd[1]);
+		talloc_free(result);
+		CTDB_DECREMENT_STAT(ctdb_db->ctdb, pending_childwrite_calls);
+		return NULL;
+	}
+
+	result->callback = callback;
+	result->private_data = state;
+	result->ctdb = ctdb_db->ctdb;
+	result->ctdb_db = ctdb_db;
+
+	if (result->child == 0) {
+		char c = 0;
+
+		close(result->fd[0]);
+		prctl_set_comment("ctdb_write_persistent");
+		ret = ctdb_persistent_store(state);
+		if (ret != 0) {
+			DEBUG(DEBUG_ERR, (__location__ " Failed to write persistent data\n"));
+			c = 1;
+		}
+
+		sys_write(result->fd[1], &c, 1);
+
+		ctdb_wait_for_process_to_exit(parent);
+		_exit(0);
+	}
+
+	close(result->fd[1]);
+	set_close_on_exec(result->fd[0]);
+
+	talloc_set_destructor(result, childwrite_destructor);
+
+	DEBUG(DEBUG_DEBUG, (__location__ " Created PIPE FD:%d for ctdb_childwrite\n", result->fd[0]));
+
+	result->fde = tevent_add_fd(ctdb_db->ctdb->ev, result, result->fd[0],
+				    TEVENT_FD_READ, childwrite_handler,
+				    (void *)result);
+	if (result->fde == NULL) {
+		talloc_free(result);
+		CTDB_DECREMENT_STAT(ctdb_db->ctdb, pending_childwrite_calls);
+		return NULL;
+	}
+	tevent_fd_set_auto_close(result->fde);
+
+	result->start_time = timeval_current();
+
+	return result;
+}
+
+/*
+   update a record on this node if the new record has a higher rsn than the
+   current record
+ */
+int32_t ctdb_control_update_record(struct ctdb_context *ctdb,
+				   struct ctdb_req_control_old *c, TDB_DATA recdata,
+				   bool *async_reply)
+{
+	struct ctdb_db_context *ctdb_db;
+	struct ctdb_persistent_write_state *state;
+	struct childwrite_handle *handle;
+	struct ctdb_marshall_buffer *m = (struct ctdb_marshall_buffer *)recdata.dptr;
+
+	if (ctdb->recovery_mode != CTDB_RECOVERY_NORMAL) {
+		DEBUG(DEBUG_INFO,("rejecting ctdb_control_update_record when recovery active\n"));
+		return -1;
+	}
+
+	ctdb_db = find_ctdb_db(ctdb, m->db_id);
+	if (ctdb_db == NULL) {
+		DEBUG(DEBUG_ERR,("Unknown database 0x%08x in ctdb_control_update_record\n", m->db_id));
+		return -1;
+	}
+
+	if (ctdb_db->unhealthy_reason) {
+		DEBUG(DEBUG_ERR,("db(%s) unhealty in ctdb_control_update_record: %s\n",
+				 ctdb_db->db_name, ctdb_db->unhealthy_reason));
+		return -1;
+	}
+
+	state = talloc(ctdb, struct ctdb_persistent_write_state);
+	CTDB_NO_MEMORY(ctdb, state);
+
+	state->ctdb_db = ctdb_db;
+	state->c       = c;
+	state->m       = m;
+	state->flags   = 0;
+	if (ctdb_db_volatile(ctdb_db)) {
+		state->flags   = UPDATE_FLAGS_REPLACE_ONLY;
+	}
+
+	/* create a child process to take out a transaction and
+	   write the data.
+	*/
+	handle = ctdb_childwrite(ctdb_db, ctdb_persistent_write_callback, state);
+	if (handle == NULL) {
+		DEBUG(DEBUG_ERR,("Failed to setup childwrite handler in ctdb_control_update_record\n"));
+		talloc_free(state);
+		return -1;
+	}
+
+	/* we need to wait for the replies */
+	*async_reply = true;
+
+	/* need to keep the control structure around */
+	talloc_steal(state, c);
+
+	/* but we won't wait forever */
+	tevent_add_timer(ctdb->ev, state,
+			 timeval_current_ofs(ctdb->tunable.control_timeout, 0),
+			 ctdb_persistent_lock_timeout, state);
+
+	return 0;
+}
+