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https://github.com/samba-team/samba.git
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b99436e425
Signed-off-by: Amitay Isaacs <amitay@gmail.com> Reviewed-by: Martin Schwenke <martin@meltin.net>
372 lines
10 KiB
C
372 lines
10 KiB
C
/*
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implementation of the update record control
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Copyright (C) Andrew Tridgell 2007
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Copyright (C) Ronnie Sahlberg 2007
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "replace.h"
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#include "system/network.h"
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#include "system/time.h"
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#include <talloc.h>
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#include <tevent.h>
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#include "lib/tdb_wrap/tdb_wrap.h"
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#include "lib/util/debug.h"
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#include "lib/util/samba_util.h"
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#include "ctdb_private.h"
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#include "ctdb_client.h"
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#include "ctdb_logging.h"
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#include "common/system.h"
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#include "common/common.h"
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struct ctdb_persistent_write_state {
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struct ctdb_db_context *ctdb_db;
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struct ctdb_marshall_buffer *m;
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struct ctdb_req_control_old *c;
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uint32_t flags;
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};
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/* dont create/update records that does not exist locally */
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#define UPDATE_FLAGS_REPLACE_ONLY 1
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/*
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called from a child process to write the data
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*/
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static int ctdb_persistent_store(struct ctdb_persistent_write_state *state)
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{
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int ret, i;
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struct ctdb_rec_data_old *rec = NULL;
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struct ctdb_marshall_buffer *m = state->m;
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ret = tdb_transaction_start(state->ctdb_db->ltdb->tdb);
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if (ret == -1) {
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DEBUG(DEBUG_ERR,("Failed to start transaction for db_id 0x%08x in ctdb_persistent_store\n",
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state->ctdb_db->db_id));
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return -1;
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}
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for (i=0;i<m->count;i++) {
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struct ctdb_ltdb_header oldheader;
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struct ctdb_ltdb_header header;
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TDB_DATA key, data, olddata;
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TALLOC_CTX *tmp_ctx = talloc_new(state);
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rec = ctdb_marshall_loop_next(m, rec, NULL, &header, &key, &data);
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if (rec == NULL) {
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DEBUG(DEBUG_ERR,("Failed to get next record %d for db_id 0x%08x in ctdb_persistent_store\n",
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i, state->ctdb_db->db_id));
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talloc_free(tmp_ctx);
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goto failed;
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}
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/* we must check if the record exists or not because
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ctdb_ltdb_fetch will unconditionally create a record
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*/
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if (state->flags & UPDATE_FLAGS_REPLACE_ONLY) {
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TDB_DATA trec;
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trec = tdb_fetch(state->ctdb_db->ltdb->tdb, key);
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if (trec.dsize == 0) {
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talloc_free(tmp_ctx);
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continue;
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}
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free(trec.dptr);
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}
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/* fetch the old header and ensure the rsn is less than the new rsn */
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ret = ctdb_ltdb_fetch(state->ctdb_db, key, &oldheader, tmp_ctx, &olddata);
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if (ret != 0) {
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DEBUG(DEBUG_ERR,("Failed to fetch old record for db_id 0x%08x in ctdb_persistent_store\n",
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state->ctdb_db->db_id));
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talloc_free(tmp_ctx);
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goto failed;
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}
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if (oldheader.rsn >= header.rsn &&
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(olddata.dsize != data.dsize ||
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memcmp(olddata.dptr, data.dptr, data.dsize) != 0)) {
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DEBUG(DEBUG_CRIT,("existing header for db_id 0x%08x has larger RSN %llu than new RSN %llu in ctdb_persistent_store\n",
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state->ctdb_db->db_id,
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(unsigned long long)oldheader.rsn, (unsigned long long)header.rsn));
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talloc_free(tmp_ctx);
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goto failed;
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}
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talloc_free(tmp_ctx);
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ret = ctdb_ltdb_store(state->ctdb_db, key, &header, data);
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if (ret != 0) {
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DEBUG(DEBUG_CRIT,("Failed to store record for db_id 0x%08x in ctdb_persistent_store\n",
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state->ctdb_db->db_id));
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goto failed;
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}
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}
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ret = tdb_transaction_commit(state->ctdb_db->ltdb->tdb);
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if (ret == -1) {
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DEBUG(DEBUG_ERR,("Failed to commit transaction for db_id 0x%08x in ctdb_persistent_store\n",
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state->ctdb_db->db_id));
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return -1;
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}
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return 0;
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failed:
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tdb_transaction_cancel(state->ctdb_db->ltdb->tdb);
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return -1;
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}
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/*
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called when we the child has completed the persistent write
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on our behalf
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*/
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static void ctdb_persistent_write_callback(int status, void *private_data)
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{
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struct ctdb_persistent_write_state *state = talloc_get_type(private_data,
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struct ctdb_persistent_write_state);
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ctdb_request_control_reply(state->ctdb_db->ctdb, state->c, NULL, status, NULL);
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talloc_free(state);
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}
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/*
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called if our lockwait child times out
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*/
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static void ctdb_persistent_lock_timeout(struct tevent_context *ev,
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struct tevent_timer *te,
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struct timeval t, void *private_data)
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{
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struct ctdb_persistent_write_state *state = talloc_get_type(private_data,
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struct ctdb_persistent_write_state);
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ctdb_request_control_reply(state->ctdb_db->ctdb, state->c, NULL, -1, "timeout in ctdb_persistent_lock");
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talloc_free(state);
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}
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struct childwrite_handle {
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struct ctdb_context *ctdb;
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struct ctdb_db_context *ctdb_db;
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struct tevent_fd *fde;
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int fd[2];
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pid_t child;
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void *private_data;
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void (*callback)(int, void *);
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struct timeval start_time;
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};
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static int childwrite_destructor(struct childwrite_handle *h)
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{
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CTDB_DECREMENT_STAT(h->ctdb, pending_childwrite_calls);
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ctdb_kill(h->ctdb, h->child, SIGKILL);
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return 0;
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}
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/* called when the child process has finished writing the record to the
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database
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*/
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static void childwrite_handler(struct tevent_context *ev,
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struct tevent_fd *fde,
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uint16_t flags, void *private_data)
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{
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struct childwrite_handle *h = talloc_get_type(private_data,
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struct childwrite_handle);
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void *p = h->private_data;
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void (*callback)(int, void *) = h->callback;
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pid_t child = h->child;
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TALLOC_CTX *tmp_ctx = talloc_new(ev);
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int ret;
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char c;
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CTDB_UPDATE_LATENCY(h->ctdb, h->ctdb_db, "persistent", childwrite_latency, h->start_time);
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CTDB_DECREMENT_STAT(h->ctdb, pending_childwrite_calls);
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/* the handle needs to go away when the context is gone - when
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the handle goes away this implicitly closes the pipe, which
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kills the child */
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talloc_steal(tmp_ctx, h);
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talloc_set_destructor(h, NULL);
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ret = sys_read(h->fd[0], &c, 1);
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if (ret < 1) {
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DEBUG(DEBUG_ERR, (__location__ " Read returned %d. Childwrite failed\n", ret));
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c = 1;
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}
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callback(c, p);
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ctdb_kill(h->ctdb, child, SIGKILL);
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talloc_free(tmp_ctx);
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}
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/* this creates a child process which will take out a tdb transaction
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and write the record to the database.
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*/
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static struct childwrite_handle *ctdb_childwrite(
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struct ctdb_db_context *ctdb_db,
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void (*callback)(int, void *private_data),
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struct ctdb_persistent_write_state *state)
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{
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struct childwrite_handle *result;
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int ret;
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pid_t parent = getpid();
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CTDB_INCREMENT_STAT(ctdb_db->ctdb, childwrite_calls);
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CTDB_INCREMENT_STAT(ctdb_db->ctdb, pending_childwrite_calls);
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if (!(result = talloc_zero(state, struct childwrite_handle))) {
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CTDB_DECREMENT_STAT(ctdb_db->ctdb, pending_childwrite_calls);
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return NULL;
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}
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ret = pipe(result->fd);
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if (ret != 0) {
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talloc_free(result);
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CTDB_DECREMENT_STAT(ctdb_db->ctdb, pending_childwrite_calls);
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return NULL;
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}
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result->child = ctdb_fork(ctdb_db->ctdb);
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if (result->child == (pid_t)-1) {
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close(result->fd[0]);
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close(result->fd[1]);
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talloc_free(result);
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CTDB_DECREMENT_STAT(ctdb_db->ctdb, pending_childwrite_calls);
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return NULL;
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}
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result->callback = callback;
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result->private_data = state;
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result->ctdb = ctdb_db->ctdb;
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result->ctdb_db = ctdb_db;
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if (result->child == 0) {
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char c = 0;
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close(result->fd[0]);
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ctdb_set_process_name("ctdb_write_persistent");
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debug_extra = talloc_asprintf(NULL, "childwrite-%s:", ctdb_db->db_name);
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ret = ctdb_persistent_store(state);
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if (ret != 0) {
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DEBUG(DEBUG_ERR, (__location__ " Failed to write persistent data\n"));
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c = 1;
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}
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sys_write(result->fd[1], &c, 1);
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/* make sure we die when our parent dies */
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while (ctdb_kill(ctdb_db->ctdb, parent, 0) == 0 || errno != ESRCH) {
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sleep(5);
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}
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_exit(0);
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}
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close(result->fd[1]);
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set_close_on_exec(result->fd[0]);
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talloc_set_destructor(result, childwrite_destructor);
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DEBUG(DEBUG_DEBUG, (__location__ " Created PIPE FD:%d for ctdb_childwrite\n", result->fd[0]));
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result->fde = tevent_add_fd(ctdb_db->ctdb->ev, result, result->fd[0],
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TEVENT_FD_READ, childwrite_handler,
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(void *)result);
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if (result->fde == NULL) {
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talloc_free(result);
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CTDB_DECREMENT_STAT(ctdb_db->ctdb, pending_childwrite_calls);
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return NULL;
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}
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tevent_fd_set_auto_close(result->fde);
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result->start_time = timeval_current();
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return result;
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}
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/*
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update a record on this node if the new record has a higher rsn than the
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current record
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*/
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int32_t ctdb_control_update_record(struct ctdb_context *ctdb,
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struct ctdb_req_control_old *c, TDB_DATA recdata,
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bool *async_reply)
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{
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struct ctdb_db_context *ctdb_db;
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struct ctdb_persistent_write_state *state;
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struct childwrite_handle *handle;
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struct ctdb_marshall_buffer *m = (struct ctdb_marshall_buffer *)recdata.dptr;
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if (ctdb->recovery_mode != CTDB_RECOVERY_NORMAL) {
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DEBUG(DEBUG_INFO,("rejecting ctdb_control_update_record when recovery active\n"));
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return -1;
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}
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ctdb_db = find_ctdb_db(ctdb, m->db_id);
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if (ctdb_db == NULL) {
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DEBUG(DEBUG_ERR,("Unknown database 0x%08x in ctdb_control_update_record\n", m->db_id));
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return -1;
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}
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if (ctdb_db->unhealthy_reason) {
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DEBUG(DEBUG_ERR,("db(%s) unhealty in ctdb_control_update_record: %s\n",
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ctdb_db->db_name, ctdb_db->unhealthy_reason));
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return -1;
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}
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state = talloc(ctdb, struct ctdb_persistent_write_state);
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CTDB_NO_MEMORY(ctdb, state);
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state->ctdb_db = ctdb_db;
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state->c = c;
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state->m = m;
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state->flags = 0;
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if (!ctdb_db->persistent) {
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state->flags = UPDATE_FLAGS_REPLACE_ONLY;
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}
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/* create a child process to take out a transaction and
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write the data.
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*/
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handle = ctdb_childwrite(ctdb_db, ctdb_persistent_write_callback, state);
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if (handle == NULL) {
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DEBUG(DEBUG_ERR,("Failed to setup childwrite handler in ctdb_control_update_record\n"));
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talloc_free(state);
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return -1;
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}
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/* we need to wait for the replies */
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*async_reply = true;
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/* need to keep the control structure around */
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talloc_steal(state, c);
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/* but we won't wait forever */
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tevent_add_timer(ctdb->ev, state,
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timeval_current_ofs(ctdb->tunable.control_timeout, 0),
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ctdb_persistent_lock_timeout, state);
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return 0;
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}
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