/* 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 . */ #include "replace.h" #include "system/network.h" #include "system/time.h" #include #include #include "lib/tdb_wrap/tdb_wrap.h" #include "lib/util/debug.h" #include "lib/util/samba_util.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) { int ret, i; 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;icount;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) { DEBUG(DEBUG_ERR,("Failed to get next record %d 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"); debug_extra = talloc_asprintf(NULL, "childwrite-%s:", ctdb_db->db_name); 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); /* make sure we die when our parent dies */ while (ctdb_kill(ctdb_db->ctdb, parent, 0) == 0 || errno != ESRCH) { sleep(5); } _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->persistent) { 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; }