Adding upstream version 2:4.17.12+dfsg.upstream/2%4.17.12+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1990 insertions, 0 deletions

diff --git a/ctdb/server/ctdb_vacuum.c b/ctdb/server/ctdb_vacuum.c
new file mode 100644
index 0000000..74d7215
--- /dev/null
+++ b/ctdb/server/ctdb_vacuum.c
@@ -0,0 +1,1990 @@
+/*
+   ctdb vacuuming events
+
+   Copyright (C) Ronnie Sahlberg  2009
+   Copyright (C) Michael Adam 2010-2013
+   Copyright (C) Stefan Metzmacher 2010-2011
+
+   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
+   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/filesys.h"
+#include "system/time.h"
+
+#include <talloc.h>
+#include <tevent.h>
+
+#include "lib/tdb_wrap/tdb_wrap.h"
+#include "lib/util/dlinklist.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 "protocol/protocol_private.h"
+
+#include "common/rb_tree.h"
+#include "common/common.h"
+#include "common/logging.h"
+
+#include "protocol/protocol_api.h"
+
+#define TIMELIMIT() timeval_current_ofs(10, 0)
+
+enum vacuum_child_status { VACUUM_RUNNING, VACUUM_OK, VACUUM_ERROR, VACUUM_TIMEOUT};
+
+struct ctdb_vacuum_child_context {
+	struct ctdb_vacuum_handle *vacuum_handle;
+	/* fd child writes status to */
+	int fd[2];
+	pid_t child_pid;
+	enum vacuum_child_status status;
+	struct timeval start_time;
+	bool scheduled;
+};
+
+struct ctdb_vacuum_handle {
+	struct ctdb_db_context *ctdb_db;
+	uint32_t fast_path_count;
+	uint32_t vacuum_interval;
+};
+
+
+/*  a list of records to possibly delete */
+struct vacuum_data {
+	struct ctdb_context *ctdb;
+	struct ctdb_db_context *ctdb_db;
+	struct tdb_context *dest_db;
+	trbt_tree_t *delete_list;
+	struct ctdb_marshall_buffer **vacuum_fetch_list;
+	struct timeval start;
+	bool traverse_error;
+	bool vacuum;
+	struct {
+		struct {
+			uint32_t added_to_vacuum_fetch_list;
+			uint32_t added_to_delete_list;
+			uint32_t deleted;
+			uint32_t skipped;
+			uint32_t error;
+			uint32_t total;
+		} delete_queue;
+		struct {
+			uint32_t scheduled;
+			uint32_t skipped;
+			uint32_t error;
+			uint32_t total;
+		} db_traverse;
+		struct {
+			uint32_t total;
+			uint32_t remote_error;
+			uint32_t local_error;
+			uint32_t deleted;
+			uint32_t skipped;
+			uint32_t left;
+		} delete_list;
+		struct {
+			uint32_t vacuumed;
+			uint32_t copied;
+		} repack;
+	} count;
+};
+
+/* this structure contains the information for one record to be deleted */
+struct delete_record_data {
+	struct ctdb_context *ctdb;
+	struct ctdb_db_context *ctdb_db;
+	struct ctdb_ltdb_header hdr;
+	uint32_t remote_fail_count;
+	TDB_DATA key;
+	uint8_t keydata[1];
+};
+
+struct delete_records_list {
+	struct ctdb_marshall_buffer *records;
+	struct vacuum_data *vdata;
+};
+
+struct fetch_record_data {
+	TDB_DATA key;
+	uint8_t keydata[1];
+};
+
+static int insert_record_into_delete_queue(struct ctdb_db_context *ctdb_db,
+					   const struct ctdb_ltdb_header *hdr,
+					   TDB_DATA key);
+
+/**
+ * Store key and header in a tree, indexed by the key hash.
+ */
+static int insert_delete_record_data_into_tree(struct ctdb_context *ctdb,
+					       struct ctdb_db_context *ctdb_db,
+					       trbt_tree_t *tree,
+					       const struct ctdb_ltdb_header *hdr,
+					       TDB_DATA key)
+{
+	struct delete_record_data *dd;
+	uint32_t hash;
+	size_t len;
+
+	len = offsetof(struct delete_record_data, keydata) + key.dsize;
+
+	dd = (struct delete_record_data *)talloc_size(tree, len);
+	if (dd == NULL) {
+		DEBUG(DEBUG_ERR,(__location__ " Out of memory\n"));
+		return -1;
+	}
+	talloc_set_name_const(dd, "struct delete_record_data");
+
+	dd->ctdb      = ctdb;
+	dd->ctdb_db   = ctdb_db;
+	dd->key.dsize = key.dsize;
+	dd->key.dptr  = dd->keydata;
+	memcpy(dd->keydata, key.dptr, key.dsize);
+
+	dd->hdr = *hdr;
+	dd->remote_fail_count = 0;
+
+	hash = ctdb_hash(&key);
+
+	trbt_insert32(tree, hash, dd);
+
+	return 0;
+}
+
+static int add_record_to_delete_list(struct vacuum_data *vdata, TDB_DATA key,
+				     struct ctdb_ltdb_header *hdr)
+{
+	struct ctdb_context *ctdb = vdata->ctdb;
+	struct ctdb_db_context *ctdb_db = vdata->ctdb_db;
+	uint32_t hash;
+	int ret;
+
+	hash = ctdb_hash(&key);
+
+	if (trbt_lookup32(vdata->delete_list, hash)) {
+		DEBUG(DEBUG_INFO, (__location__ " Hash collision when vacuuming, skipping this record.\n"));
+		return 0;
+	}
+
+	ret = insert_delete_record_data_into_tree(ctdb, ctdb_db,
+						  vdata->delete_list,
+						  hdr, key);
+	if (ret != 0) {
+		return -1;
+	}
+
+	vdata->count.delete_list.total++;
+
+	return 0;
+}
+
+/**
+ * Add a record to the list of records to be sent
+ * to their lmaster with VACUUM_FETCH.
+ */
+static int add_record_to_vacuum_fetch_list(struct vacuum_data *vdata,
+					   TDB_DATA key)
+{
+	struct ctdb_context *ctdb = vdata->ctdb;
+	uint32_t lmaster;
+	struct ctdb_marshall_buffer *vfl;
+
+	lmaster = ctdb_lmaster(ctdb, &key);
+
+	vfl = vdata->vacuum_fetch_list[lmaster];
+
+	vfl = ctdb_marshall_add(ctdb, vfl, vfl->db_id, ctdb->pnn,
+				key, NULL, tdb_null);
+	if (vfl == NULL) {
+		DEBUG(DEBUG_ERR,(__location__ " Out of memory\n"));
+		vdata->traverse_error = true;
+		return -1;
+	}
+
+	vdata->vacuum_fetch_list[lmaster] = vfl;
+
+	return 0;
+}
+
+
+static void ctdb_vacuum_event(struct tevent_context *ev,
+			      struct tevent_timer *te,
+			      struct timeval t, void *private_data);
+
+static int vacuum_record_parser(TDB_DATA key, TDB_DATA data, void *private_data)
+{
+	struct ctdb_ltdb_header *header =
+		(struct ctdb_ltdb_header *)private_data;
+
+	if (data.dsize != sizeof(struct ctdb_ltdb_header)) {
+		return -1;
+	}
+
+	*header = *(struct ctdb_ltdb_header *)data.dptr;
+
+	return 0;
+}
+
+/*
+ * traverse function for gathering the records that can be deleted
+ */
+static int vacuum_traverse(struct tdb_context *tdb, TDB_DATA key, TDB_DATA data,
+			   void *private_data)
+{
+	struct vacuum_data *vdata = talloc_get_type(private_data,
+						    struct vacuum_data);
+	struct ctdb_context *ctdb = vdata->ctdb;
+	struct ctdb_db_context *ctdb_db = vdata->ctdb_db;
+	uint32_t lmaster;
+	struct ctdb_ltdb_header *hdr;
+	int res = 0;
+
+	vdata->count.db_traverse.total++;
+
+	lmaster = ctdb_lmaster(ctdb, &key);
+	if (lmaster >= ctdb->num_nodes) {
+		vdata->count.db_traverse.error++;
+		DEBUG(DEBUG_CRIT, (__location__
+				   " lmaster[%u] >= ctdb->num_nodes[%u] for key"
+				   " with hash[%u]!\n",
+				   (unsigned)lmaster,
+				   (unsigned)ctdb->num_nodes,
+				   (unsigned)ctdb_hash(&key)));
+		return -1;
+	}
+
+	if (data.dsize != sizeof(struct ctdb_ltdb_header)) {
+		/* it is not a deleted record */
+		vdata->count.db_traverse.skipped++;
+		return 0;
+	}
+
+	hdr = (struct ctdb_ltdb_header *)data.dptr;
+
+	if (hdr->dmaster != ctdb->pnn) {
+		vdata->count.db_traverse.skipped++;
+		return 0;
+	}
+
+	/*
+	 * Add the record to this process's delete_queue for processing
+	 * in the subsequent traverse in the fast vacuum run.
+	 */
+	res = insert_record_into_delete_queue(ctdb_db, hdr, key);
+	if (res != 0) {
+		vdata->count.db_traverse.error++;
+	} else {
+		vdata->count.db_traverse.scheduled++;
+	}
+
+	return 0;
+}
+
+/*
+ * traverse the tree of records to delete and marshall them into
+ * a blob
+ */
+static int delete_marshall_traverse(void *param, void *data)
+{
+	struct delete_record_data *dd = talloc_get_type(data, struct delete_record_data);
+	struct delete_records_list *recs = talloc_get_type(param, struct delete_records_list);
+	struct ctdb_marshall_buffer *m;
+
+	m = ctdb_marshall_add(recs, recs->records, recs->records->db_id,
+			      recs->records->db_id,
+			      dd->key, &dd->hdr, tdb_null);
+	if (m == NULL) {
+		DEBUG(DEBUG_ERR, (__location__ " failed to marshall record\n"));
+		return -1;
+	}
+
+	recs->records = m;
+	return 0;
+}
+
+struct fetch_queue_state {
+	struct ctdb_db_context *ctdb_db;
+	int count;
+};
+
+struct fetch_record_migrate_state {
+	struct fetch_queue_state *fetch_queue;
+	TDB_DATA key;
+};
+
+static void fetch_record_migrate_callback(struct ctdb_client_call_state *state)
+{
+	struct fetch_record_migrate_state *fetch = talloc_get_type_abort(
+		state->async.private_data, struct fetch_record_migrate_state);
+	struct fetch_queue_state *fetch_queue = fetch->fetch_queue;
+	struct ctdb_ltdb_header hdr;
+	struct ctdb_call call = { 0 };
+	int ret;
+
+	ret = ctdb_call_recv(state, &call);
+	fetch_queue->count--;
+	if (ret != 0) {
+		D_ERR("Failed to migrate record for vacuuming\n");
+		goto done;
+	}
+
+	ret = tdb_chainlock_nonblock(fetch_queue->ctdb_db->ltdb->tdb,
+				     fetch->key);
+	if (ret != 0) {
+		goto done;
+	}
+
+	ret = tdb_parse_record(fetch_queue->ctdb_db->ltdb->tdb,
+			       fetch->key,
+			       vacuum_record_parser,
+			       &hdr);
+
+	tdb_chainunlock(fetch_queue->ctdb_db->ltdb->tdb, fetch->key);
+
+	if (ret != 0) {
+		goto done;
+	}
+
+	D_INFO("Vacuum Fetch record, key=%.*s\n",
+	       (int)fetch->key.dsize,
+	       fetch->key.dptr);
+
+	(void) ctdb_local_schedule_for_deletion(fetch_queue->ctdb_db,
+						&hdr,
+						fetch->key);
+
+done:
+	talloc_free(fetch);
+}
+
+static int fetch_record_parser(TDB_DATA key, TDB_DATA data, void *private_data)
+{
+	struct ctdb_ltdb_header *header =
+		(struct ctdb_ltdb_header *)private_data;
+
+	if (data.dsize < sizeof(struct ctdb_ltdb_header)) {
+		return -1;
+	}
+
+	memcpy(header, data.dptr, sizeof(*header));
+	return 0;
+}
+
+/**
+ * traverse function for the traversal of the fetch_queue.
+ *
+ * Send a record migration request.
+ */
+static int fetch_queue_traverse(void *param, void *data)
+{
+	struct fetch_record_data *rd = talloc_get_type_abort(
+		data, struct fetch_record_data);
+	struct fetch_queue_state *fetch_queue =
+		(struct fetch_queue_state *)param;
+	struct ctdb_db_context *ctdb_db = fetch_queue->ctdb_db;
+	struct ctdb_client_call_state *state;
+	struct fetch_record_migrate_state *fetch;
+	struct ctdb_call call = { 0 };
+	struct ctdb_ltdb_header header;
+	int ret;
+
+	ret = tdb_chainlock_nonblock(ctdb_db->ltdb->tdb, rd->key);
+	if (ret != 0) {
+		return 0;
+	}
+
+	ret = tdb_parse_record(ctdb_db->ltdb->tdb,
+			       rd->key,
+			       fetch_record_parser,
+			       &header);
+
+	tdb_chainunlock(ctdb_db->ltdb->tdb, rd->key);
+
+	if (ret != 0) {
+		goto skipped;
+	}
+
+	if (header.dmaster == ctdb_db->ctdb->pnn) {
+		/* If the record is already migrated, skip */
+		goto skipped;
+	}
+
+	fetch = talloc_zero(ctdb_db, struct fetch_record_migrate_state);
+	if (fetch == NULL) {
+		D_ERR("Failed to setup fetch record migrate state\n");
+		return 0;
+	}
+
+	fetch->fetch_queue = fetch_queue;
+
+	fetch->key.dsize = rd->key.dsize;
+	fetch->key.dptr = talloc_memdup(fetch, rd->key.dptr, rd->key.dsize);
+	if (fetch->key.dptr == NULL) {
+		D_ERR("Memory error in fetch_queue_traverse\n");
+		talloc_free(fetch);
+		return 0;
+	}
+
+	call.call_id = CTDB_NULL_FUNC;
+	call.flags = CTDB_IMMEDIATE_MIGRATION |
+		     CTDB_CALL_FLAG_VACUUM_MIGRATION;
+	call.key = fetch->key;
+
+	state = ctdb_call_send(ctdb_db, &call);
+	if (state == NULL) {
+		DEBUG(DEBUG_ERR, ("Failed to setup vacuum fetch call\n"));
+		talloc_free(fetch);
+		return 0;
+	}
+
+	state->async.fn = fetch_record_migrate_callback;
+	state->async.private_data = fetch;
+
+	fetch_queue->count++;
+
+	return 0;
+
+skipped:
+	D_INFO("Skipped Fetch record, key=%.*s\n",
+	       (int)rd->key.dsize,
+	       rd->key.dptr);
+	return 0;
+}
+
+/**
+ * Traverse the fetch.
+ * Records are migrated to the local node and
+ * added to delete queue for further processing.
+ */
+static void ctdb_process_fetch_queue(struct ctdb_db_context *ctdb_db)
+{
+	struct fetch_queue_state state;
+	int ret;
+
+	state.ctdb_db = ctdb_db;
+	state.count = 0;
+
+	ret = trbt_traversearray32(ctdb_db->fetch_queue, 1,
+				   fetch_queue_traverse, &state);
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR, (__location__ " Error traversing "
+		      "the fetch queue.\n"));
+	}
+
+	/* Wait for all migrations to complete */
+	while (state.count > 0) {
+		tevent_loop_once(ctdb_db->ctdb->ev);
+	}
+}
+
+/**
+ * traverse function for the traversal of the delete_queue,
+ * the fast-path vacuuming list.
+ *
+ *  - If the record has been migrated off the node
+ *    or has been revived (filled with data) on the node,
+ *    then skip the record.
+ *
+ *  - If the current node is the record's lmaster and it is
+ *    a record that has never been migrated with data, then
+ *    delete the record from the local tdb.
+ *
+ *  - If the current node is the record's lmaster and it has
+ *    been migrated with data, then schedule it for the normal
+ *    vacuuming procedure (i.e. add it to the delete_list).
+ *
+ *  - If the current node is NOT the record's lmaster then
+ *    add it to the list of records that are to be sent to
+ *    the lmaster with the VACUUM_FETCH message.
+ */
+static int delete_queue_traverse(void *param, void *data)
+{
+	struct delete_record_data *dd =
+		talloc_get_type(data, struct delete_record_data);
+	struct vacuum_data *vdata = talloc_get_type(param, struct vacuum_data);
+	struct ctdb_db_context *ctdb_db = dd->ctdb_db;
+	struct ctdb_context *ctdb = ctdb_db->ctdb; /* or dd->ctdb ??? */
+	int res;
+	struct ctdb_ltdb_header header;
+	uint32_t lmaster;
+	uint32_t hash = ctdb_hash(&(dd->key));
+
+	vdata->count.delete_queue.total++;
+
+	res = tdb_chainlock_nonblock(ctdb_db->ltdb->tdb, dd->key);
+	if (res != 0) {
+		vdata->count.delete_queue.error++;
+		return 0;
+	}
+
+	res = tdb_parse_record(ctdb_db->ltdb->tdb, dd->key,
+			       vacuum_record_parser, &header);
+	if (res != 0) {
+		goto skipped;
+	}
+
+	if (header.dmaster != ctdb->pnn) {
+		/* The record has been migrated off the node. Skip. */
+		goto skipped;
+	}
+
+	if (header.rsn != dd->hdr.rsn) {
+		/*
+		 * The record has been migrated off the node and back again.
+		 * But not requeued for deletion. Skip it.
+		 */
+		goto skipped;
+	}
+
+	/*
+	 * We are dmaster, and the record has no data, and it has
+	 * not been migrated after it has been queued for deletion.
+	 *
+	 * At this stage, the record could still have been revived locally
+	 * and last been written with empty data. This can only be
+	 * fixed with the addition of an active or delete flag. (TODO)
+	 */
+
+	lmaster = ctdb_lmaster(ctdb_db->ctdb, &dd->key);
+
+	if (lmaster != ctdb->pnn) {
+		res = add_record_to_vacuum_fetch_list(vdata, dd->key);
+
+		if (res != 0) {
+			DEBUG(DEBUG_ERR,
+			      (__location__ " Error adding record to list "
+			       "of records to send to lmaster.\n"));
+			vdata->count.delete_queue.error++;
+		} else {
+			vdata->count.delete_queue.added_to_vacuum_fetch_list++;
+		}
+		goto done;
+	}
+
+	/* use header->flags or dd->hdr.flags ?? */
+	if (dd->hdr.flags & CTDB_REC_FLAG_MIGRATED_WITH_DATA) {
+		res = add_record_to_delete_list(vdata, dd->key, &dd->hdr);
+
+		if (res != 0) {
+			DEBUG(DEBUG_ERR,
+			      (__location__ " Error adding record to list "
+			       "of records for deletion on lmaster.\n"));
+			vdata->count.delete_queue.error++;
+		} else {
+			vdata->count.delete_queue.added_to_delete_list++;
+		}
+	} else {
+		res = tdb_delete(ctdb_db->ltdb->tdb, dd->key);
+
+		if (res != 0) {
+			DEBUG(DEBUG_ERR,
+			      (__location__ " Error deleting record with key "
+			       "hash [0x%08x] from local data base db[%s].\n",
+			       hash, ctdb_db->db_name));
+			vdata->count.delete_queue.error++;
+			goto done;
+		}
+
+		DEBUG(DEBUG_DEBUG,
+		      (__location__ " Deleted record with key hash "
+		       "[0x%08x] from local data base db[%s].\n",
+		       hash, ctdb_db->db_name));
+		vdata->count.delete_queue.deleted++;
+	}
+
+	goto done;
+
+skipped:
+	vdata->count.delete_queue.skipped++;
+
+done:
+	tdb_chainunlock(ctdb_db->ltdb->tdb, dd->key);
+
+	return 0;
+}
+
+/**
+ * Delete the records that we are lmaster and dmaster for and
+ * that could be deleted on all other nodes via the TRY_DELETE_RECORDS
+ * control.
+ */
+static int delete_record_traverse(void *param, void *data)
+{
+	struct delete_record_data *dd =
+		talloc_get_type(data, struct delete_record_data);
+	struct vacuum_data *vdata = talloc_get_type(param, struct vacuum_data);
+	struct ctdb_db_context *ctdb_db = dd->ctdb_db;
+	struct ctdb_context *ctdb = ctdb_db->ctdb;
+	int res;
+	struct ctdb_ltdb_header header;
+	uint32_t lmaster;
+	uint32_t hash = ctdb_hash(&(dd->key));
+
+	if (dd->remote_fail_count > 0) {
+		vdata->count.delete_list.remote_error++;
+		vdata->count.delete_list.left--;
+		talloc_free(dd);
+		return 0;
+	}
+
+	res = tdb_chainlock(ctdb_db->ltdb->tdb, dd->key);
+	if (res != 0) {
+		DEBUG(DEBUG_ERR,
+		      (__location__ " Error getting chainlock on record with "
+		       "key hash [0x%08x] on database db[%s].\n",
+		       hash, ctdb_db->db_name));
+		vdata->count.delete_list.local_error++;
+		vdata->count.delete_list.left--;
+		talloc_free(dd);
+		return 0;
+	}
+
+	/*
+	 * Verify that the record is still empty, its RSN has not
+	 * changed and that we are still its lmaster and dmaster.
+	 */
+
+	res = tdb_parse_record(ctdb_db->ltdb->tdb, dd->key,
+			       vacuum_record_parser, &header);
+	if (res != 0) {
+		goto skip;
+	}
+
+	if (header.flags & CTDB_REC_RO_FLAGS) {
+		DEBUG(DEBUG_INFO, (__location__ ": record with hash [0x%08x] "
+				   "on database db[%s] has read-only flags. "
+				   "skipping.\n",
+				   hash, ctdb_db->db_name));
+		goto skip;
+	}
+
+	if (header.dmaster != ctdb->pnn) {
+		DEBUG(DEBUG_INFO, (__location__ ": record with hash [0x%08x] "
+				   "on database db[%s] has been migrated away. "
+				   "skipping.\n",
+				   hash, ctdb_db->db_name));
+		goto skip;
+	}
+
+	if (header.rsn != dd->hdr.rsn) {
+		/*
+		 * The record has been migrated off the node and back again.
+		 * But not requeued for deletion. Skip it.
+		 */
+		DEBUG(DEBUG_INFO, (__location__ ": record with hash [0x%08x] "
+				   "on database db[%s] seems to have been "
+				   "migrated away and back again (with empty "
+				   "data). skipping.\n",
+				   hash, ctdb_db->db_name));
+		goto skip;
+	}
+
+	lmaster = ctdb_lmaster(ctdb_db->ctdb, &dd->key);
+
+	if (lmaster != ctdb->pnn) {
+		DEBUG(DEBUG_INFO, (__location__ ": not lmaster for record in "
+				   "delete list (key hash [0x%08x], db[%s]). "
+				   "Strange! skipping.\n",
+				   hash, ctdb_db->db_name));
+		goto skip;
+	}
+
+	res = tdb_delete(ctdb_db->ltdb->tdb, dd->key);
+
+	if (res != 0) {
+		DEBUG(DEBUG_ERR,
+		      (__location__ " Error deleting record with key hash "
+		       "[0x%08x] from local data base db[%s].\n",
+		       hash, ctdb_db->db_name));
+		vdata->count.delete_list.local_error++;
+		goto done;
+	}
+
+	DEBUG(DEBUG_DEBUG,
+	      (__location__ " Deleted record with key hash [0x%08x] from "
+	       "local data base db[%s].\n", hash, ctdb_db->db_name));
+
+	vdata->count.delete_list.deleted++;
+	goto done;
+
+skip:
+	vdata->count.delete_list.skipped++;
+
+done:
+	tdb_chainunlock(ctdb_db->ltdb->tdb, dd->key);
+
+	talloc_free(dd);
+	vdata->count.delete_list.left--;
+
+	return 0;
+}
+
+/**
+ * Traverse the delete_queue.
+ * Records are either deleted directly or filled
+ * into the delete list or the vacuum fetch lists
+ * for further processing.
+ */
+static void ctdb_process_delete_queue(struct ctdb_db_context *ctdb_db,
+				      struct vacuum_data *vdata)
+{
+	uint32_t sum;
+	int ret;
+
+	ret = trbt_traversearray32(ctdb_db->delete_queue, 1,
+				   delete_queue_traverse, vdata);
+
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR, (__location__ " Error traversing "
+		      "the delete queue.\n"));
+	}
+
+	sum = vdata->count.delete_queue.deleted
+	    + vdata->count.delete_queue.skipped
+	    + vdata->count.delete_queue.error
+	    + vdata->count.delete_queue.added_to_delete_list
+	    + vdata->count.delete_queue.added_to_vacuum_fetch_list;
+
+	if (vdata->count.delete_queue.total != sum) {
+		DEBUG(DEBUG_ERR, (__location__ " Inconsistency in fast vacuum "
+		      "counts for db[%s]: total[%u] != sum[%u]\n",
+		      ctdb_db->db_name,
+		      (unsigned)vdata->count.delete_queue.total,
+		      (unsigned)sum));
+	}
+
+	if (vdata->count.delete_queue.total > 0) {
+		DEBUG(DEBUG_INFO,
+		      (__location__
+		       " fast vacuuming delete_queue traverse statistics: "
+		       "db[%s] "
+		       "total[%u] "
+		       "del[%u] "
+		       "skp[%u] "
+		       "err[%u] "
+		       "adl[%u] "
+		       "avf[%u]\n",
+		       ctdb_db->db_name,
+		       (unsigned)vdata->count.delete_queue.total,
+		       (unsigned)vdata->count.delete_queue.deleted,
+		       (unsigned)vdata->count.delete_queue.skipped,
+		       (unsigned)vdata->count.delete_queue.error,
+		       (unsigned)vdata->count.delete_queue.added_to_delete_list,
+		       (unsigned)vdata->count.delete_queue.added_to_vacuum_fetch_list));
+	}
+
+	return;
+}
+
+/**
+ * read-only traverse of the database, looking for records that
+ * might be able to be vacuumed.
+ *
+ * This is not done each time but only every tunable
+ * VacuumFastPathCount times.
+ */
+static void ctdb_vacuum_traverse_db(struct ctdb_db_context *ctdb_db,
+				    struct vacuum_data *vdata)
+{
+	int ret;
+
+	ret = tdb_traverse_read(ctdb_db->ltdb->tdb, vacuum_traverse, vdata);
+	if (ret == -1 || vdata->traverse_error) {
+		DEBUG(DEBUG_ERR, (__location__ " Traverse error in vacuuming "
+				  "'%s'\n", ctdb_db->db_name));
+		return;
+	}
+
+	if (vdata->count.db_traverse.total > 0) {
+		DEBUG(DEBUG_INFO,
+		      (__location__
+		       " full vacuuming db traverse statistics: "
+		       "db[%s] "
+		       "total[%u] "
+		       "skp[%u] "
+		       "err[%u] "
+		       "sched[%u]\n",
+		       ctdb_db->db_name,
+		       (unsigned)vdata->count.db_traverse.total,
+		       (unsigned)vdata->count.db_traverse.skipped,
+		       (unsigned)vdata->count.db_traverse.error,
+		       (unsigned)vdata->count.db_traverse.scheduled));
+	}
+
+	return;
+}
+
+/**
+ * Process the vacuum fetch lists:
+ * For records for which we are not the lmaster, tell the lmaster to
+ * fetch the record.
+ */
+static void ctdb_process_vacuum_fetch_lists(struct ctdb_db_context *ctdb_db,
+					    struct vacuum_data *vdata)
+{
+	unsigned int i;
+	struct ctdb_context *ctdb = ctdb_db->ctdb;
+	int ret, res;
+
+	for (i = 0; i < ctdb->num_nodes; i++) {
+		TDB_DATA data;
+		struct ctdb_marshall_buffer *vfl = vdata->vacuum_fetch_list[i];
+
+		if (ctdb->nodes[i]->pnn == ctdb->pnn) {
+			continue;
+		}
+
+		if (vfl->count == 0) {
+			continue;
+		}
+
+		DEBUG(DEBUG_INFO, ("Found %u records for lmaster %u in '%s'\n",
+				   vfl->count, ctdb->nodes[i]->pnn,
+				   ctdb_db->db_name));
+
+		data = ctdb_marshall_finish(vfl);
+
+		ret = ctdb_control(ctdb, ctdb->nodes[i]->pnn, 0,
+				   CTDB_CONTROL_VACUUM_FETCH, 0,
+				   data, NULL, NULL, &res, NULL, NULL);
+		if (ret != 0 || res != 0) {
+			DEBUG(DEBUG_ERR, ("Failed to send vacuum "
+					  "fetch control to node %u\n",
+					  ctdb->nodes[i]->pnn));
+		}
+	}
+}
+
+/**
+ * Process the delete list:
+ *
+ * This is the last step of vacuuming that consistently deletes
+ * those records that have been migrated with data and can hence
+ * not be deleted when leaving a node.
+ *
+ * In this step, the lmaster does the final deletion of those empty
+ * records that it is also dmaster for. It has ususally received
+ * at least some of these records previously from the former dmasters
+ * with the vacuum fetch message.
+ *
+ *  1) Send the records to all active nodes with the TRY_DELETE_RECORDS
+ *     control. The remote notes delete their local copy.
+ *  2) The lmaster locally deletes its copies of all records that
+ *     could successfully be deleted remotely in step #2.
+ */
+static void ctdb_process_delete_list(struct ctdb_db_context *ctdb_db,
+				     struct vacuum_data *vdata)
+{
+	int ret, i;
+	struct ctdb_context *ctdb = ctdb_db->ctdb;
+	struct delete_records_list *recs;
+	TDB_DATA indata;
+	struct ctdb_node_map_old *nodemap;
+	uint32_t *active_nodes;
+	int num_active_nodes;
+	TALLOC_CTX *tmp_ctx;
+	uint32_t sum;
+
+	if (vdata->count.delete_list.total == 0) {
+		return;
+	}
+
+	tmp_ctx = talloc_new(vdata);
+	if (tmp_ctx == NULL) {
+		DEBUG(DEBUG_ERR,(__location__ " Out of memory\n"));
+		return;
+	}
+
+	vdata->count.delete_list.left = vdata->count.delete_list.total;
+
+	/*
+	 * get the list of currently active nodes
+	 */
+
+	ret = ctdb_ctrl_getnodemap(ctdb, TIMELIMIT(),
+				   CTDB_CURRENT_NODE,
+				   tmp_ctx,
+				   &nodemap);
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR,(__location__ " unable to get node map\n"));
+		goto done;
+	}
+
+	active_nodes = list_of_active_nodes(ctdb, nodemap,
+					    nodemap, /* talloc context */
+					    false /* include self */);
+	/* yuck! ;-) */
+	num_active_nodes = talloc_get_size(active_nodes)/sizeof(*active_nodes);
+
+	/*
+	 * Now delete the records all active nodes in a two-phase process:
+	 * 1) tell all active remote nodes to delete all their copy
+	 * 2) if all remote nodes deleted their record copy, delete it locally
+	 */
+
+	recs = talloc_zero(tmp_ctx, struct delete_records_list);
+	if (recs == NULL) {
+		DEBUG(DEBUG_ERR,(__location__ " Out of memory\n"));
+		goto done;
+	}
+
+	/*
+	 * Step 1:
+	 * Send all records to all active nodes for deletion.
+	 */
+
+	/*
+	 * Create a marshall blob from the remaining list of records to delete.
+	 */
+
+	recs->records = (struct ctdb_marshall_buffer *)
+		talloc_zero_size(recs,
+				 offsetof(struct ctdb_marshall_buffer, data));
+	if (recs->records == NULL) {
+		DEBUG(DEBUG_ERR,(__location__ " Out of memory\n"));
+		goto done;
+	}
+	recs->records->db_id = ctdb_db->db_id;
+
+	ret = trbt_traversearray32(vdata->delete_list, 1,
+				   delete_marshall_traverse, recs);
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR, (__location__ " Error traversing the "
+		      "delete list for second marshalling.\n"));
+		goto done;
+	}
+
+	indata = ctdb_marshall_finish(recs->records);
+
+	for (i = 0; i < num_active_nodes; i++) {
+		struct ctdb_marshall_buffer *records;
+		struct ctdb_rec_data_old *rec;
+		int32_t res;
+		TDB_DATA outdata;
+
+		ret = ctdb_control(ctdb, active_nodes[i], 0,
+				CTDB_CONTROL_TRY_DELETE_RECORDS, 0,
+				indata, recs, &outdata, &res,
+				NULL, NULL);
+		if (ret != 0 || res != 0) {
+			DEBUG(DEBUG_ERR, ("Failed to delete records on "
+					  "node %u: ret[%d] res[%d]\n",
+					  active_nodes[i], ret, res));
+			goto done;
+		}
+
+		/*
+		 * outdata contains the list of records coming back
+		 * from the node: These are the records that the
+		 * remote node could not delete. We remove these from
+		 * the list to delete locally.
+		 */
+		records = (struct ctdb_marshall_buffer *)outdata.dptr;
+		rec = (struct ctdb_rec_data_old *)&records->data[0];
+		while (records->count-- > 0) {
+			TDB_DATA reckey, recdata;
+			struct ctdb_ltdb_header *rechdr;
+			struct delete_record_data *dd;
+
+			reckey.dptr = &rec->data[0];
+			reckey.dsize = rec->keylen;
+			recdata.dptr = &rec->data[reckey.dsize];
+			recdata.dsize = rec->datalen;
+
+			if (recdata.dsize < sizeof(struct ctdb_ltdb_header)) {
+				DEBUG(DEBUG_CRIT,(__location__ " bad ltdb record\n"));
+				goto done;
+			}
+			rechdr = (struct ctdb_ltdb_header *)recdata.dptr;
+			recdata.dptr += sizeof(*rechdr);
+			recdata.dsize -= sizeof(*rechdr);
+
+			dd = (struct delete_record_data *)trbt_lookup32(
+					vdata->delete_list,
+					ctdb_hash(&reckey));
+			if (dd != NULL) {
+				/*
+				 * The remote node could not delete the
+				 * record.  Since other remote nodes can
+				 * also fail, we just mark the record.
+				 */
+				dd->remote_fail_count++;
+			} else {
+				DEBUG(DEBUG_ERR, (__location__ " Failed to "
+				      "find record with hash 0x%08x coming "
+				      "back from TRY_DELETE_RECORDS "
+				      "control in delete list.\n",
+				      ctdb_hash(&reckey)));
+			}
+
+			rec = (struct ctdb_rec_data_old *)(rec->length + (uint8_t *)rec);
+		}
+	}
+
+	/*
+	 * Step 2:
+	 * Delete the remaining records locally.
+	 *
+	 * These records have successfully been deleted on all
+	 * active remote nodes.
+	 */
+
+	ret = trbt_traversearray32(vdata->delete_list, 1,
+				   delete_record_traverse, vdata);
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR, (__location__ " Error traversing the "
+		      "delete list for deletion.\n"));
+	}
+
+	if (vdata->count.delete_list.left != 0) {
+		DEBUG(DEBUG_ERR, (__location__ " Vaccum db[%s] error: "
+		      "there are %u records left for deletion after "
+		      "processing delete list\n",
+		      ctdb_db->db_name,
+		      (unsigned)vdata->count.delete_list.left));
+	}
+
+	sum = vdata->count.delete_list.deleted
+	    + vdata->count.delete_list.skipped
+	    + vdata->count.delete_list.remote_error
+	    + vdata->count.delete_list.local_error
+	    + vdata->count.delete_list.left;
+
+	if (vdata->count.delete_list.total != sum) {
+		DEBUG(DEBUG_ERR, (__location__ " Inconsistency in vacuum "
+		      "delete list counts for db[%s]: total[%u] != sum[%u]\n",
+		      ctdb_db->db_name,
+		      (unsigned)vdata->count.delete_list.total,
+		      (unsigned)sum));
+	}
+
+	if (vdata->count.delete_list.total > 0) {
+		DEBUG(DEBUG_INFO,
+		      (__location__
+		       " vacuum delete list statistics: "
+		       "db[%s] "
+		       "total[%u] "
+		       "del[%u] "
+		       "skip[%u] "
+		       "rem.err[%u] "
+		       "loc.err[%u] "
+		       "left[%u]\n",
+		       ctdb_db->db_name,
+		       (unsigned)vdata->count.delete_list.total,
+		       (unsigned)vdata->count.delete_list.deleted,
+		       (unsigned)vdata->count.delete_list.skipped,
+		       (unsigned)vdata->count.delete_list.remote_error,
+		       (unsigned)vdata->count.delete_list.local_error,
+		       (unsigned)vdata->count.delete_list.left));
+	}
+
+done:
+	talloc_free(tmp_ctx);
+
+	return;
+}
+
+/**
+ * initialize the vacuum_data
+ */
+static struct vacuum_data *ctdb_vacuum_init_vacuum_data(
+					struct ctdb_db_context *ctdb_db,
+					TALLOC_CTX *mem_ctx)
+{
+	unsigned int i;
+	struct ctdb_context *ctdb = ctdb_db->ctdb;
+	struct vacuum_data *vdata;
+
+	vdata = talloc_zero(mem_ctx, struct vacuum_data);
+	if (vdata == NULL) {
+		DEBUG(DEBUG_ERR,(__location__ " Out of memory\n"));
+		return NULL;
+	}
+
+	vdata->ctdb = ctdb_db->ctdb;
+	vdata->ctdb_db = ctdb_db;
+	vdata->delete_list = trbt_create(vdata, 0);
+	if (vdata->delete_list == NULL) {
+		DEBUG(DEBUG_ERR,(__location__ " Out of memory\n"));
+		goto fail;
+	}
+
+	vdata->start = timeval_current();
+
+	vdata->count.delete_queue.added_to_delete_list = 0;
+	vdata->count.delete_queue.added_to_vacuum_fetch_list = 0;
+	vdata->count.delete_queue.deleted = 0;
+	vdata->count.delete_queue.skipped = 0;
+	vdata->count.delete_queue.error = 0;
+	vdata->count.delete_queue.total = 0;
+	vdata->count.db_traverse.scheduled = 0;
+	vdata->count.db_traverse.skipped = 0;
+	vdata->count.db_traverse.error = 0;
+	vdata->count.db_traverse.total = 0;
+	vdata->count.delete_list.total = 0;
+	vdata->count.delete_list.left = 0;
+	vdata->count.delete_list.remote_error = 0;
+	vdata->count.delete_list.local_error = 0;
+	vdata->count.delete_list.skipped = 0;
+	vdata->count.delete_list.deleted = 0;
+
+	/* the list needs to be of length num_nodes */
+	vdata->vacuum_fetch_list = talloc_zero_array(vdata,
+						struct ctdb_marshall_buffer *,
+						ctdb->num_nodes);
+	if (vdata->vacuum_fetch_list == NULL) {
+		DEBUG(DEBUG_ERR,(__location__ " Out of memory\n"));
+		goto fail;
+	}
+	for (i = 0; i < ctdb->num_nodes; i++) {
+		vdata->vacuum_fetch_list[i] = (struct ctdb_marshall_buffer *)
+			talloc_zero_size(vdata->vacuum_fetch_list,
+					 offsetof(struct ctdb_marshall_buffer, data));
+		if (vdata->vacuum_fetch_list[i] == NULL) {
+			DEBUG(DEBUG_ERR,(__location__ " Out of memory\n"));
+			talloc_free(vdata);
+			return NULL;
+		}
+		vdata->vacuum_fetch_list[i]->db_id = ctdb_db->db_id;
+	}
+
+	return vdata;
+
+fail:
+	talloc_free(vdata);
+	return NULL;
+}
+
+/**
+ * Vacuum a DB:
+ *  - Always do the fast vacuuming run, which traverses
+ *    - the in-memory fetch queue: these records have been
+ *      scheduled for migration
+ *    - the in-memory delete queue: these records have been
+ *      scheduled for deletion.
+ *  - Only if explicitly requested, the database is traversed
+ *    in order to use the traditional heuristics on empty records
+ *    to trigger deletion.
+ *    This is done only every VacuumFastPathCount'th vacuuming run.
+ *
+ * The traverse runs fill two lists:
+ *
+ * - The delete_list:
+ *   This is the list of empty records the current
+ *   node is lmaster and dmaster for. These records are later
+ *   deleted first on other nodes and then locally.
+ *
+ *   The fast vacuuming run has a short cut for those records
+ *   that have never been migrated with data: these records
+ *   are immediately deleted locally, since they have left
+ *   no trace on other nodes.
+ *
+ * - The vacuum_fetch lists
+ *   (one for each other lmaster node):
+ *   The records in this list are sent for deletion to
+ *   their lmaster in a bulk VACUUM_FETCH control.
+ *
+ *   The lmaster then migrates all these records to itelf
+ *   so that they can be vacuumed there.
+ *
+ * This executes in the child context.
+ */
+static int ctdb_vacuum_db(struct ctdb_db_context *ctdb_db,
+			  bool full_vacuum_run)
+{
+	struct ctdb_context *ctdb = ctdb_db->ctdb;
+	int ret, pnn;
+	struct vacuum_data *vdata;
+	TALLOC_CTX *tmp_ctx;
+
+	DEBUG(DEBUG_INFO, (__location__ " Entering %s vacuum run for db "
+			   "%s db_id[0x%08x]\n",
+			   full_vacuum_run ? "full" : "fast",
+			   ctdb_db->db_name, ctdb_db->db_id));
+
+	ret = ctdb_ctrl_getvnnmap(ctdb, TIMELIMIT(), CTDB_CURRENT_NODE, ctdb, &ctdb->vnn_map);
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR, ("Unable to get vnnmap from local node\n"));
+		return ret;
+	}
+
+	pnn = ctdb_ctrl_getpnn(ctdb, TIMELIMIT(), CTDB_CURRENT_NODE);
+	if (pnn == -1) {
+		DEBUG(DEBUG_ERR, ("Unable to get pnn from local node\n"));
+		return -1;
+	}
+
+	ctdb->pnn = pnn;
+
+	tmp_ctx = talloc_new(ctdb_db);
+	if (tmp_ctx == NULL) {
+		DEBUG(DEBUG_ERR, ("Out of memory!\n"));
+		return -1;
+	}
+
+	vdata = ctdb_vacuum_init_vacuum_data(ctdb_db, tmp_ctx);
+	if (vdata == NULL) {
+		talloc_free(tmp_ctx);
+		return -1;
+	}
+
+	if (full_vacuum_run) {
+		ctdb_vacuum_traverse_db(ctdb_db, vdata);
+	}
+
+	ctdb_process_fetch_queue(ctdb_db);
+
+	ctdb_process_delete_queue(ctdb_db, vdata);
+
+	ctdb_process_vacuum_fetch_lists(ctdb_db, vdata);
+
+	ctdb_process_delete_list(ctdb_db, vdata);
+
+	talloc_free(tmp_ctx);
+
+	return 0;
+}
+
+/*
+ * repack and vaccum a db
+ * called from the child context
+ */
+static int ctdb_vacuum_and_repack_db(struct ctdb_db_context *ctdb_db,
+				     bool full_vacuum_run)
+{
+	uint32_t repack_limit = ctdb_db->ctdb->tunable.repack_limit;
+	const char *name = ctdb_db->db_name;
+	int freelist_size = 0;
+	int ret;
+
+	if (ctdb_vacuum_db(ctdb_db, full_vacuum_run) != 0) {
+		DEBUG(DEBUG_ERR,(__location__ " Failed to vacuum '%s'\n", name));
+	}
+
+	freelist_size = tdb_freelist_size(ctdb_db->ltdb->tdb);
+	if (freelist_size == -1) {
+		DEBUG(DEBUG_ERR,(__location__ " Failed to get freelist size for '%s'\n", name));
+		return -1;
+	}
+
+	/*
+	 * decide if a repack is necessary
+	 */
+	if ((repack_limit == 0 || (uint32_t)freelist_size < repack_limit))
+	{
+		return 0;
+	}
+
+	D_NOTICE("Repacking %s with %u freelist entries\n",
+		 name,
+		 freelist_size);
+
+	ret = tdb_repack(ctdb_db->ltdb->tdb);
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR,(__location__ " Failed to repack '%s'\n", name));
+		return -1;
+	}
+
+	return 0;
+}
+
+static uint32_t get_vacuum_interval(struct ctdb_db_context *ctdb_db)
+{
+	uint32_t interval = ctdb_db->ctdb->tunable.vacuum_interval;
+
+	return interval;
+}
+
+static int vacuum_child_destructor(struct ctdb_vacuum_child_context *child_ctx)
+{
+	double l = timeval_elapsed(&child_ctx->start_time);
+	struct ctdb_vacuum_handle *vacuum_handle = child_ctx->vacuum_handle;
+	struct ctdb_db_context *ctdb_db = vacuum_handle->ctdb_db;
+	struct ctdb_context *ctdb = ctdb_db->ctdb;
+
+	CTDB_UPDATE_DB_LATENCY(ctdb_db, "vacuum", vacuum.latency, l);
+	DEBUG(DEBUG_INFO,("Vacuuming took %.3f seconds for database %s\n", l, ctdb_db->db_name));
+
+	if (child_ctx->child_pid != -1) {
+		ctdb_kill(ctdb, child_ctx->child_pid, SIGKILL);
+	} else {
+		/* Bump the number of successful fast-path runs. */
+		vacuum_handle->fast_path_count++;
+	}
+
+	ctdb->vacuumer = NULL;
+
+	if (child_ctx->scheduled) {
+		vacuum_handle->vacuum_interval = get_vacuum_interval(ctdb_db);
+
+		tevent_add_timer(
+			ctdb->ev,
+			vacuum_handle,
+			timeval_current_ofs(vacuum_handle->vacuum_interval, 0),
+			ctdb_vacuum_event,
+			vacuum_handle);
+	}
+
+	return 0;
+}
+
+/*
+ * this event is generated when a vacuum child process times out
+ */
+static void vacuum_child_timeout(struct tevent_context *ev,
+				 struct tevent_timer *te,
+				 struct timeval t, void *private_data)
+{
+	struct ctdb_vacuum_child_context *child_ctx = talloc_get_type(private_data, struct ctdb_vacuum_child_context);
+
+	DEBUG(DEBUG_ERR,("Vacuuming child process timed out for db %s\n", child_ctx->vacuum_handle->ctdb_db->db_name));
+
+	child_ctx->status = VACUUM_TIMEOUT;
+
+	talloc_free(child_ctx);
+}
+
+
+/*
+ * this event is generated when a vacuum child process has completed
+ */
+static void vacuum_child_handler(struct tevent_context *ev,
+				 struct tevent_fd *fde,
+				 uint16_t flags, void *private_data)
+{
+	struct ctdb_vacuum_child_context *child_ctx = talloc_get_type(private_data, struct ctdb_vacuum_child_context);
+	char c = 0;
+	int ret;
+
+	DEBUG(DEBUG_INFO,("Vacuuming child process %d finished for db %s\n", child_ctx->child_pid, child_ctx->vacuum_handle->ctdb_db->db_name));
+	child_ctx->child_pid = -1;
+
+	ret = sys_read(child_ctx->fd[0], &c, 1);
+	if (ret != 1 || c != 0) {
+		child_ctx->status = VACUUM_ERROR;
+		DEBUG(DEBUG_ERR, ("A vacuum child process failed with an error for database %s. ret=%d c=%d\n", child_ctx->vacuum_handle->ctdb_db->db_name, ret, c));
+	} else {
+		child_ctx->status = VACUUM_OK;
+	}
+
+	talloc_free(child_ctx);
+}
+
+/*
+ * this event is called every time we need to start a new vacuum process
+ */
+static int vacuum_db_child(TALLOC_CTX *mem_ctx,
+			   struct ctdb_db_context *ctdb_db,
+			   bool scheduled,
+			   bool full_vacuum_run,
+			   struct ctdb_vacuum_child_context **out)
+{
+	struct ctdb_context *ctdb = ctdb_db->ctdb;
+	struct ctdb_vacuum_child_context *child_ctx;
+	struct tevent_fd *fde;
+	int ret;
+
+	/* we don't vacuum if we are in recovery mode, or db frozen */
+	if (ctdb->recovery_mode == CTDB_RECOVERY_ACTIVE ||
+	    ctdb_db_frozen(ctdb_db)) {
+		D_INFO("Not vacuuming %s (%s)\n", ctdb_db->db_name,
+		       ctdb->recovery_mode == CTDB_RECOVERY_ACTIVE ?
+		       "in recovery" : "frozen");
+		return EAGAIN;
+	}
+
+	/* Do not allow multiple vacuuming child processes to be active at the
+	 * same time.  If there is vacuuming child process active, delay
+	 * new vacuuming event to stagger vacuuming events.
+	 */
+	if (ctdb->vacuumer != NULL) {
+		return EBUSY;
+	}
+
+	child_ctx = talloc_zero(mem_ctx, struct ctdb_vacuum_child_context);
+	if (child_ctx == NULL) {
+		DBG_ERR("Failed to allocate child context for vacuuming of %s\n",
+			ctdb_db->db_name);
+		return ENOMEM;
+	}
+
+
+	ret = pipe(child_ctx->fd);
+	if (ret != 0) {
+		talloc_free(child_ctx);
+		D_ERR("Failed to create pipe for vacuum child process.\n");
+		return EAGAIN;
+	}
+
+	child_ctx->child_pid = ctdb_fork(ctdb);
+	if (child_ctx->child_pid == (pid_t)-1) {
+		close(child_ctx->fd[0]);
+		close(child_ctx->fd[1]);
+		talloc_free(child_ctx);
+		D_ERR("Failed to fork vacuum child process.\n");
+		return EAGAIN;
+	}
+
+
+	if (child_ctx->child_pid == 0) {
+		char cc = 0;
+		close(child_ctx->fd[0]);
+
+		D_INFO("Vacuuming child process %d for db %s started\n",
+		       getpid(),
+		       ctdb_db->db_name);
+		prctl_set_comment("ctdb_vacuum");
+		ret = switch_from_server_to_client(ctdb);
+		if (ret != 0) {
+			DBG_ERR("ERROR: failed to switch vacuum daemon "
+				"into client mode.\n");
+			return EIO;
+		}
+
+		cc = ctdb_vacuum_and_repack_db(ctdb_db, full_vacuum_run);
+
+		sys_write(child_ctx->fd[1], &cc, 1);
+		_exit(0);
+	}
+
+	set_close_on_exec(child_ctx->fd[0]);
+	close(child_ctx->fd[1]);
+
+	child_ctx->status = VACUUM_RUNNING;
+	child_ctx->scheduled = scheduled;
+	child_ctx->start_time = timeval_current();
+
+	ctdb->vacuumer = child_ctx;
+	talloc_set_destructor(child_ctx, vacuum_child_destructor);
+
+	/*
+	 * Clear the fastpath vacuuming list in the parent.
+	 */
+	talloc_free(ctdb_db->delete_queue);
+	ctdb_db->delete_queue = trbt_create(ctdb_db, 0);
+	if (ctdb_db->delete_queue == NULL) {
+		DBG_ERR("Out of memory when re-creating vacuum tree\n");
+		return ENOMEM;
+	}
+
+	talloc_free(ctdb_db->fetch_queue);
+	ctdb_db->fetch_queue = trbt_create(ctdb_db, 0);
+	if (ctdb_db->fetch_queue == NULL) {
+		ctdb_fatal(ctdb, "Out of memory when re-create fetch queue "
+				 " in parent context. Shutting down\n");
+	}
+
+	tevent_add_timer(ctdb->ev, child_ctx,
+			 timeval_current_ofs(ctdb->tunable.vacuum_max_run_time,
+					     0),
+			 vacuum_child_timeout, child_ctx);
+
+	DBG_DEBUG(" Created PIPE FD:%d to child vacuum process\n",
+		  child_ctx->fd[0]);
+
+	fde = tevent_add_fd(ctdb->ev, child_ctx, child_ctx->fd[0],
+			    TEVENT_FD_READ, vacuum_child_handler, child_ctx);
+	tevent_fd_set_auto_close(fde);
+
+	child_ctx->vacuum_handle = ctdb_db->vacuum_handle;
+
+	*out = child_ctx;
+	return 0;
+}
+
+static void ctdb_vacuum_event(struct tevent_context *ev,
+			      struct tevent_timer *te,
+			      struct timeval t, void *private_data)
+{
+	struct ctdb_vacuum_handle *vacuum_handle = talloc_get_type(
+		private_data, struct ctdb_vacuum_handle);
+	struct ctdb_db_context *ctdb_db = vacuum_handle->ctdb_db;
+	struct ctdb_context *ctdb = ctdb_db->ctdb;
+	struct ctdb_vacuum_child_context *child_ctx = NULL;
+	uint32_t fast_path_max = ctdb->tunable.vacuum_fast_path_count;
+	uint32_t vacuum_interval = get_vacuum_interval(ctdb_db);
+	bool full_vacuum_run = false;
+	int ret;
+
+	if (vacuum_interval > vacuum_handle->vacuum_interval) {
+		uint32_t d = vacuum_interval - vacuum_handle->vacuum_interval;
+
+		DBG_INFO("Vacuum interval increased from "
+			 "%"PRIu32" to %"PRIu32", rescheduling\n",
+			 vacuum_handle->vacuum_interval,
+			 vacuum_interval);
+		vacuum_handle->vacuum_interval = vacuum_interval;
+		tevent_add_timer(ctdb->ev,
+				 vacuum_handle,
+				 timeval_current_ofs(d, 0),
+				 ctdb_vacuum_event,
+				 vacuum_handle);
+		return;
+	}
+
+	vacuum_handle->vacuum_interval = vacuum_interval;
+
+	if (vacuum_handle->fast_path_count >= fast_path_max) {
+		if (fast_path_max > 0) {
+			full_vacuum_run = true;
+		}
+		vacuum_handle->fast_path_count = 0;
+	}
+
+	ret = vacuum_db_child(vacuum_handle,
+			      ctdb_db,
+			      true,
+			      full_vacuum_run,
+			      &child_ctx);
+
+	if (ret == 0) {
+		return;
+	}
+
+	switch (ret) {
+	case EBUSY:
+		/* Stagger */
+		tevent_add_timer(ctdb->ev,
+				 vacuum_handle,
+				 timeval_current_ofs(0, 500*1000),
+				 ctdb_vacuum_event,
+				 vacuum_handle);
+		break;
+
+	default:
+		/* Temporary failure, schedule next attempt */
+		tevent_add_timer(ctdb->ev,
+				 vacuum_handle,
+				 timeval_current_ofs(
+					 vacuum_handle->vacuum_interval, 0),
+				 ctdb_vacuum_event,
+				 vacuum_handle);
+	}
+
+}
+
+struct vacuum_control_state {
+	struct ctdb_vacuum_child_context *child_ctx;
+	struct ctdb_req_control_old *c;
+	struct ctdb_context *ctdb;
+};
+
+static int vacuum_control_state_destructor(struct vacuum_control_state *state)
+{
+	struct ctdb_vacuum_child_context *child_ctx = state->child_ctx;
+	int32_t status;
+
+	status = (child_ctx->status == VACUUM_OK ? 0 : -1);
+	ctdb_request_control_reply(state->ctdb, state->c, NULL, status, NULL);
+
+	return 0;
+}
+
+int32_t ctdb_control_db_vacuum(struct ctdb_context *ctdb,
+			       struct ctdb_req_control_old *c,
+			       TDB_DATA indata,
+			       bool *async_reply)
+{
+	struct ctdb_db_context *ctdb_db;
+	struct ctdb_vacuum_child_context *child_ctx = NULL;
+	struct ctdb_db_vacuum *db_vacuum;
+	struct vacuum_control_state *state;
+	size_t np;
+	int ret;
+
+	ret = ctdb_db_vacuum_pull(indata.dptr,
+				  indata.dsize,
+				  ctdb,
+				  &db_vacuum,
+				  &np);
+	if (ret != 0) {
+		DBG_ERR("Invalid data\n");
+		return -1;
+	}
+
+	ctdb_db = find_ctdb_db(ctdb, db_vacuum->db_id);
+	if (ctdb_db == NULL) {
+		DBG_ERR("Unknown db id 0x%08x\n", db_vacuum->db_id);
+		talloc_free(db_vacuum);
+		return -1;
+	}
+
+	state = talloc(ctdb, struct vacuum_control_state);
+	if (state == NULL) {
+		DBG_ERR("Memory allocation error\n");
+		return -1;
+	}
+
+	ret = vacuum_db_child(ctdb_db,
+			      ctdb_db,
+			      false,
+			      db_vacuum->full_vacuum_run,
+			      &child_ctx);
+
+	talloc_free(db_vacuum);
+
+	if (ret == 0) {
+		(void) talloc_steal(child_ctx, state);
+
+		state->child_ctx = child_ctx;
+		state->c = talloc_steal(state, c);
+		state->ctdb = ctdb;
+
+		talloc_set_destructor(state, vacuum_control_state_destructor);
+
+		*async_reply = true;
+		return 0;
+	}
+
+	talloc_free(state);
+
+	switch (ret) {
+	case EBUSY:
+		DBG_WARNING("Vacuuming collision\n");
+		break;
+
+	default:
+		DBG_ERR("Temporary vacuuming failure, ret=%d\n", ret);
+	}
+
+	return -1;
+}
+
+void ctdb_stop_vacuuming(struct ctdb_context *ctdb)
+{
+	if (ctdb->vacuumer != NULL) {
+		D_INFO("Aborting vacuuming for %s (%i)\n",
+		       ctdb->vacuumer->vacuum_handle->ctdb_db->db_name,
+		       (int)ctdb->vacuumer->child_pid);
+		/* vacuum_child_destructor kills it, removes from list */
+		talloc_free(ctdb->vacuumer);
+	}
+}
+
+/* this function initializes the vacuuming context for a database
+ * starts the vacuuming events
+ */
+int ctdb_vacuum_init(struct ctdb_db_context *ctdb_db)
+{
+	struct ctdb_vacuum_handle *vacuum_handle;
+
+	if (! ctdb_db_volatile(ctdb_db)) {
+		DEBUG(DEBUG_ERR,
+		      ("Vacuuming is disabled for non-volatile database %s\n",
+		       ctdb_db->db_name));
+		return 0;
+	}
+
+	vacuum_handle = talloc(ctdb_db, struct ctdb_vacuum_handle);
+	if (vacuum_handle == NULL) {
+		DBG_ERR("Memory allocation error\n");
+		return -1;
+	}
+
+	vacuum_handle->ctdb_db = ctdb_db;
+	vacuum_handle->fast_path_count = 0;
+	vacuum_handle->vacuum_interval = get_vacuum_interval(ctdb_db);
+
+	ctdb_db->vacuum_handle = vacuum_handle;
+
+	tevent_add_timer(ctdb_db->ctdb->ev,
+			 vacuum_handle,
+			 timeval_current_ofs(vacuum_handle->vacuum_interval, 0),
+			 ctdb_vacuum_event,
+			 vacuum_handle);
+
+	return 0;
+}
+
+static void remove_record_from_delete_queue(struct ctdb_db_context *ctdb_db,
+					    const struct ctdb_ltdb_header *hdr,
+					    const TDB_DATA key)
+{
+	struct delete_record_data *kd;
+	uint32_t hash;
+
+	hash = (uint32_t)ctdb_hash(&key);
+
+	DEBUG(DEBUG_DEBUG, (__location__
+			    " remove_record_from_delete_queue: "
+			    "db[%s] "
+			    "db_id[0x%08x] "
+			    "key_hash[0x%08x] "
+			    "lmaster[%u] "
+			    "migrated_with_data[%s]\n",
+			     ctdb_db->db_name, ctdb_db->db_id,
+			     hash,
+			     ctdb_lmaster(ctdb_db->ctdb, &key),
+			     hdr->flags & CTDB_REC_FLAG_MIGRATED_WITH_DATA ? "yes" : "no"));
+
+	kd = (struct delete_record_data *)trbt_lookup32(ctdb_db->delete_queue, hash);
+	if (kd == NULL) {
+		DEBUG(DEBUG_DEBUG, (__location__
+				    " remove_record_from_delete_queue: "
+				    "record not in queue (hash[0x%08x])\n.",
+				    hash));
+		return;
+	}
+
+	if ((kd->key.dsize != key.dsize) ||
+	    (memcmp(kd->key.dptr, key.dptr, key.dsize) != 0))
+	{
+		DEBUG(DEBUG_DEBUG, (__location__
+				    " remove_record_from_delete_queue: "
+				    "hash collision for key with hash[0x%08x] "
+				    "in db[%s] - skipping\n",
+				    hash, ctdb_db->db_name));
+		return;
+	}
+
+	DEBUG(DEBUG_DEBUG, (__location__
+			    " remove_record_from_delete_queue: "
+			    "removing key with hash[0x%08x]\n",
+			     hash));
+
+	talloc_free(kd);
+
+	return;
+}
+
+/**
+ * Insert a record into the ctdb_db context's delete queue,
+ * handling hash collisions.
+ */
+static int insert_record_into_delete_queue(struct ctdb_db_context *ctdb_db,
+					   const struct ctdb_ltdb_header *hdr,
+					   TDB_DATA key)
+{
+	struct delete_record_data *kd;
+	uint32_t hash;
+	int ret;
+
+	hash = (uint32_t)ctdb_hash(&key);
+
+	DEBUG(DEBUG_DEBUG, (__location__ " schedule for deletion: db[%s] "
+			    "db_id[0x%08x] "
+			    "key_hash[0x%08x] "
+			    "lmaster[%u] "
+			    "migrated_with_data[%s]\n",
+			    ctdb_db->db_name, ctdb_db->db_id,
+			    hash,
+			    ctdb_lmaster(ctdb_db->ctdb, &key),
+			    hdr->flags & CTDB_REC_FLAG_MIGRATED_WITH_DATA ? "yes" : "no"));
+
+	kd = (struct delete_record_data *)trbt_lookup32(ctdb_db->delete_queue, hash);
+	if (kd != NULL) {
+		if ((kd->key.dsize != key.dsize) ||
+		    (memcmp(kd->key.dptr, key.dptr, key.dsize) != 0))
+		{
+			DEBUG(DEBUG_INFO,
+			      (__location__ " schedule for deletion: "
+			       "hash collision for key hash [0x%08x]. "
+			       "Skipping the record.\n", hash));
+			return 0;
+		} else {
+			DEBUG(DEBUG_DEBUG,
+			      (__location__ " schedule for deletion: "
+			       "updating entry for key with hash [0x%08x].\n",
+			       hash));
+		}
+	}
+
+	ret = insert_delete_record_data_into_tree(ctdb_db->ctdb, ctdb_db,
+						  ctdb_db->delete_queue,
+						  hdr, key);
+	if (ret != 0) {
+		DEBUG(DEBUG_INFO,
+		      (__location__ " schedule for deletion: error "
+		       "inserting key with hash [0x%08x] into delete queue\n",
+		       hash));
+		return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * Schedule a record for deletetion.
+ * Called from the parent context.
+ */
+int32_t ctdb_control_schedule_for_deletion(struct ctdb_context *ctdb,
+					   TDB_DATA indata)
+{
+	struct ctdb_control_schedule_for_deletion *dd;
+	struct ctdb_db_context *ctdb_db;
+	int ret;
+	TDB_DATA key;
+
+	dd = (struct ctdb_control_schedule_for_deletion *)indata.dptr;
+
+	ctdb_db = find_ctdb_db(ctdb, dd->db_id);
+	if (ctdb_db == NULL) {
+		DEBUG(DEBUG_ERR, (__location__ " Unknown db id 0x%08x\n",
+				  dd->db_id));
+		return -1;
+	}
+
+	key.dsize = dd->keylen;
+	key.dptr = dd->key;
+
+	ret = insert_record_into_delete_queue(ctdb_db, &dd->hdr, key);
+
+	return ret;
+}
+
+int32_t ctdb_local_schedule_for_deletion(struct ctdb_db_context *ctdb_db,
+					 const struct ctdb_ltdb_header *hdr,
+					 TDB_DATA key)
+{
+	int ret;
+	struct ctdb_control_schedule_for_deletion *dd;
+	TDB_DATA indata;
+	int32_t status;
+
+	if (ctdb_db->ctdb->ctdbd_pid == getpid()) {
+		/* main daemon - directly queue */
+		ret = insert_record_into_delete_queue(ctdb_db, hdr, key);
+
+		return ret;
+	}
+
+	/* if we don't have a connection to the daemon we can not send
+	   a control. For example sometimes from update_record control child
+	   process.
+	*/
+	if (!ctdb_db->ctdb->can_send_controls) {
+		return -1;
+	}
+
+
+	/* child process: send the main daemon a control */
+	indata.dsize = offsetof(struct ctdb_control_schedule_for_deletion, key) + key.dsize;
+	indata.dptr = talloc_zero_array(ctdb_db, uint8_t, indata.dsize);
+	if (indata.dptr == NULL) {
+		DEBUG(DEBUG_ERR, (__location__ " out of memory\n"));
+		return -1;
+	}
+	dd = (struct ctdb_control_schedule_for_deletion *)(void *)indata.dptr;
+	dd->db_id = ctdb_db->db_id;
+	dd->hdr = *hdr;
+	dd->keylen = key.dsize;
+	memcpy(dd->key, key.dptr, key.dsize);
+
+	ret = ctdb_control(ctdb_db->ctdb,
+			   CTDB_CURRENT_NODE,
+			   ctdb_db->db_id,
+			   CTDB_CONTROL_SCHEDULE_FOR_DELETION,
+			   CTDB_CTRL_FLAG_NOREPLY, /* flags */
+			   indata,
+			   NULL, /* mem_ctx */
+			   NULL, /* outdata */
+			   &status,
+			   NULL, /* timeout : NULL == wait forever */
+			   NULL); /* error message */
+
+	talloc_free(indata.dptr);
+
+	if (ret != 0 || status != 0) {
+		DEBUG(DEBUG_ERR, (__location__ " Error sending "
+				  "SCHEDULE_FOR_DELETION "
+				  "control.\n"));
+		if (status != 0) {
+			ret = -1;
+		}
+	}
+
+	return ret;
+}
+
+void ctdb_local_remove_from_delete_queue(struct ctdb_db_context *ctdb_db,
+					 const struct ctdb_ltdb_header *hdr,
+					 const TDB_DATA key)
+{
+	if (ctdb_db->ctdb->ctdbd_pid != getpid()) {
+		/*
+		 * Only remove the record from the delete queue if called
+		 * in the main daemon.
+		 */
+		return;
+	}
+
+	remove_record_from_delete_queue(ctdb_db, hdr, key);
+
+	return;
+}
+
+static int vacuum_fetch_parser(uint32_t reqid,
+			       struct ctdb_ltdb_header *header,
+			       TDB_DATA key, TDB_DATA data,
+			       void *private_data)
+{
+	struct ctdb_db_context *ctdb_db = talloc_get_type_abort(
+		private_data, struct ctdb_db_context);
+	struct fetch_record_data *rd;
+	size_t len;
+	uint32_t hash;
+
+	len = offsetof(struct fetch_record_data, keydata) + key.dsize;
+
+	rd = (struct fetch_record_data *)talloc_size(ctdb_db->fetch_queue,
+						     len);
+	if (rd == NULL) {
+		DEBUG(DEBUG_ERR, (__location__ " Memory error\n"));
+		return -1;
+	}
+	talloc_set_name_const(rd, "struct fetch_record_data");
+
+	rd->key.dsize = key.dsize;
+	rd->key.dptr = rd->keydata;
+	memcpy(rd->keydata, key.dptr, key.dsize);
+
+	hash = ctdb_hash(&key);
+
+	trbt_insert32(ctdb_db->fetch_queue, hash, rd);
+
+	return 0;
+}
+
+int32_t ctdb_control_vacuum_fetch(struct ctdb_context *ctdb, TDB_DATA indata)
+{
+	struct ctdb_rec_buffer *recbuf;
+	struct ctdb_db_context *ctdb_db;
+	size_t npull;
+	int ret;
+
+	ret = ctdb_rec_buffer_pull(indata.dptr, indata.dsize, ctdb, &recbuf,
+				   &npull);
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR, ("Invalid data in vacuum_fetch\n"));
+		return -1;
+	}
+
+	ctdb_db = find_ctdb_db(ctdb, recbuf->db_id);
+	if (ctdb_db == NULL) {
+		talloc_free(recbuf);
+		DEBUG(DEBUG_ERR, (__location__ " Unknown db 0x%08x\n",
+				  recbuf->db_id));
+		return -1;
+	}
+
+	ret = ctdb_rec_buffer_traverse(recbuf, vacuum_fetch_parser, ctdb_db);
+	talloc_free(recbuf);
+	return ret;
+}