Adding upstream version 2:4.20.0+dfsg.upstream/2%4.20.0+dfsg

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

6 files changed, 3597 insertions, 0 deletions

diff --git a/source3/lib/dbwrap/dbwrap_ctdb.c b/source3/lib/dbwrap/dbwrap_ctdb.c
new file mode 100644
index 0000000..46165e8
--- /dev/null
+++ b/source3/lib/dbwrap/dbwrap_ctdb.c
@@ -0,0 +1,1985 @@
+/*
+   Unix SMB/CIFS implementation.
+   Database interface wrapper around ctdbd
+   Copyright (C) Volker Lendecke 2007-2009
+   Copyright (C) Michael Adam 2009
+
+   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 "includes.h"
+#include "system/filesys.h"
+#include "lib/tdb_wrap/tdb_wrap.h"
+#include "util_tdb.h"
+#include "dbwrap/dbwrap.h"
+#include "dbwrap/dbwrap_ctdb.h"
+#include "dbwrap/dbwrap_rbt.h"
+#include "lib/param/param.h"
+
+#include "ctdb/include/ctdb_protocol.h"
+#include "ctdbd_conn.h"
+#include "dbwrap/dbwrap.h"
+#include "dbwrap/dbwrap_private.h"
+#include "dbwrap/dbwrap_ctdb.h"
+#include "g_lock.h"
+#include "messages.h"
+#include "messages_ctdb.h"
+#include "lib/cluster_support.h"
+#include "lib/util/tevent_ntstatus.h"
+
+struct db_ctdb_transaction_handle {
+	struct db_ctdb_ctx *ctx;
+	/*
+	 * we store the writes done under a transaction:
+	 */
+	struct ctdb_marshall_buffer *m_write;
+	uint32_t nesting;
+	bool nested_cancel;
+	char *lock_name;
+};
+
+struct db_ctdb_ctx {
+	struct db_context *db;
+	struct tdb_wrap *wtdb;
+	uint32_t db_id;
+	struct db_ctdb_transaction_handle *transaction;
+	struct g_lock_ctx *lock_ctx;
+
+	/* thresholds for warning messages */
+	int warn_unlock_msecs;
+	int warn_migrate_msecs;
+	int warn_migrate_attempts;
+	int warn_locktime_msecs;
+};
+
+struct db_ctdb_rec {
+	struct db_ctdb_ctx *ctdb_ctx;
+	struct ctdb_ltdb_header header;
+	struct timeval lock_time;
+};
+
+struct ctdb_async_ctx {
+	bool initialized;
+	struct ctdbd_connection *async_conn;
+};
+
+static struct ctdb_async_ctx ctdb_async_ctx;
+
+static int ctdb_async_ctx_init_internal(TALLOC_CTX *mem_ctx,
+					struct tevent_context *ev,
+					bool reinit)
+{
+	int ret;
+
+	if (reinit) {
+		TALLOC_FREE(ctdb_async_ctx.async_conn);
+		ctdb_async_ctx.initialized = false;
+	}
+
+	if (ctdb_async_ctx.initialized) {
+		return 0;
+	}
+
+	become_root();
+	ret = ctdbd_init_async_connection(
+		mem_ctx,
+		lp_ctdbd_socket(),
+		lp_ctdb_timeout(),
+		&ctdb_async_ctx.async_conn);
+	unbecome_root();
+
+	if (ret != 0) {
+		DBG_ERR("ctdbd_init_async_connection(%s, timeout=%d) "
+			"failed: ret=%d %s\n",
+			lp_ctdbd_socket(),
+			lp_ctdb_timeout(),
+			ret, strerror(ret));
+		return ret;
+	}
+
+	SMB_ASSERT(ctdb_async_ctx.async_conn != NULL);
+
+	ctdb_async_ctx.initialized = true;
+	return 0;
+}
+
+static int ctdb_async_ctx_init(TALLOC_CTX *mem_ctx, struct tevent_context *ev)
+{
+	return ctdb_async_ctx_init_internal(mem_ctx, ev, false);
+}
+
+int ctdb_async_ctx_reinit(TALLOC_CTX *mem_ctx, struct tevent_context *ev)
+{
+	return ctdb_async_ctx_init_internal(mem_ctx, ev, true);
+}
+
+static NTSTATUS tdb_error_to_ntstatus(struct tdb_context *tdb)
+{
+	enum TDB_ERROR tret = tdb_error(tdb);
+
+	return map_nt_error_from_tdb(tret);
+}
+
+struct db_ctdb_ltdb_parse_state {
+	void (*parser)(TDB_DATA key, struct ctdb_ltdb_header *header,
+		       TDB_DATA data, void *private_data);
+	void *private_data;
+};
+
+static int db_ctdb_ltdb_parser(TDB_DATA key, TDB_DATA data,
+			       void *private_data)
+{
+	struct db_ctdb_ltdb_parse_state *state =
+		(struct db_ctdb_ltdb_parse_state *)private_data;
+
+	if (data.dsize < sizeof(struct ctdb_ltdb_header)) {
+		return -1;
+	}
+
+	state->parser(
+		key, (struct ctdb_ltdb_header *)data.dptr,
+		make_tdb_data(data.dptr + sizeof(struct ctdb_ltdb_header),
+			      data.dsize - sizeof(struct ctdb_ltdb_header)),
+		state->private_data);
+	return 0;
+}
+
+static NTSTATUS db_ctdb_ltdb_parse(
+	struct db_ctdb_ctx *db, TDB_DATA key,
+	void (*parser)(TDB_DATA key, struct ctdb_ltdb_header *header,
+		       TDB_DATA data, void *private_data),
+	void *private_data)
+{
+	struct db_ctdb_ltdb_parse_state state;
+	int ret;
+
+	state.parser = parser;
+	state.private_data = private_data;
+
+	ret = tdb_parse_record(db->wtdb->tdb, key, db_ctdb_ltdb_parser,
+			       &state);
+	if (ret == -1) {
+		return NT_STATUS_NOT_FOUND;
+	}
+	return NT_STATUS_OK;
+}
+
+/*
+ * Store a record together with the ctdb record header
+ * in the local copy of the database.
+ */
+static NTSTATUS db_ctdb_ltdb_store(struct db_ctdb_ctx *db,
+				   TDB_DATA key,
+				   struct ctdb_ltdb_header *header,
+				   const TDB_DATA *dbufs, int num_dbufs)
+{
+	TDB_DATA recs[num_dbufs+1];
+	int ret;
+
+	recs[0] = (TDB_DATA) { .dptr = (uint8_t *)header,
+			       .dsize = sizeof(struct ctdb_ltdb_header) };
+	memcpy(&recs[1], dbufs, sizeof(TDB_DATA) * num_dbufs);
+
+	ret = tdb_storev(db->wtdb->tdb, key, recs, num_dbufs + 1, TDB_REPLACE);
+
+	return (ret == 0) ? NT_STATUS_OK
+			  : tdb_error_to_ntstatus(db->wtdb->tdb);
+
+}
+
+/*
+  form a ctdb_rec_data record from a key/data pair
+ */
+static struct ctdb_rec_data_old *db_ctdb_marshall_record(TALLOC_CTX *mem_ctx, uint32_t reqid,
+						  TDB_DATA key,
+						  struct ctdb_ltdb_header *header,
+						  TDB_DATA data)
+{
+	size_t length;
+	struct ctdb_rec_data_old *d;
+
+	length = offsetof(struct ctdb_rec_data_old, data) + key.dsize +
+		data.dsize + sizeof(*header);
+	d = (struct ctdb_rec_data_old *)talloc_size(mem_ctx, length);
+	if (d == NULL) {
+		return NULL;
+	}
+	d->length = length;
+	d->reqid = reqid;
+	d->keylen = key.dsize;
+	memcpy(&d->data[0], key.dptr, key.dsize);
+
+	d->datalen = data.dsize + sizeof(*header);
+	memcpy(&d->data[key.dsize], header, sizeof(*header));
+	memcpy(&d->data[key.dsize+sizeof(*header)], data.dptr, data.dsize);
+	return d;
+}
+
+
+/* helper function for marshalling multiple records */
+static struct ctdb_marshall_buffer *db_ctdb_marshall_add(TALLOC_CTX *mem_ctx,
+					       struct ctdb_marshall_buffer *m,
+					       uint32_t db_id,
+					       uint32_t reqid,
+					       TDB_DATA key,
+					       struct ctdb_ltdb_header *header,
+					       TDB_DATA data)
+{
+	struct ctdb_rec_data_old *r;
+	size_t m_size, r_size;
+	struct ctdb_marshall_buffer *m2 = NULL;
+
+	r = db_ctdb_marshall_record(talloc_tos(), reqid, key, header, data);
+	if (r == NULL) {
+		talloc_free(m);
+		return NULL;
+	}
+
+	if (m == NULL) {
+		m = (struct ctdb_marshall_buffer *)talloc_zero_size(
+			mem_ctx, offsetof(struct ctdb_marshall_buffer, data));
+		if (m == NULL) {
+			goto done;
+		}
+		m->db_id = db_id;
+	}
+
+	m_size = talloc_get_size(m);
+	r_size = talloc_get_size(r);
+
+	m2 = (struct ctdb_marshall_buffer *)talloc_realloc_size(
+		mem_ctx, m,  m_size + r_size);
+	if (m2 == NULL) {
+		talloc_free(m);
+		goto done;
+	}
+
+	memcpy(m_size + (uint8_t *)m2, r, r_size);
+
+	m2->count++;
+
+done:
+	talloc_free(r);
+	return m2;
+}
+
+/* we've finished marshalling, return a data blob with the marshalled records */
+static TDB_DATA db_ctdb_marshall_finish(struct ctdb_marshall_buffer *m)
+{
+	TDB_DATA data;
+	data.dptr = (uint8_t *)m;
+	data.dsize = talloc_get_size(m);
+	return data;
+}
+
+/*
+   loop over a marshalling buffer
+
+     - pass r==NULL to start
+     - loop the number of times indicated by m->count
+*/
+static struct ctdb_rec_data_old *db_ctdb_marshall_loop_next_key(
+	struct ctdb_marshall_buffer *m, struct ctdb_rec_data_old *r, TDB_DATA *key)
+{
+	if (r == NULL) {
+		r = (struct ctdb_rec_data_old *)&m->data[0];
+	} else {
+		r = (struct ctdb_rec_data_old *)(r->length + (uint8_t *)r);
+	}
+
+	key->dptr   = &r->data[0];
+	key->dsize  = r->keylen;
+	return r;
+}
+
+static bool db_ctdb_marshall_buf_parse(
+	struct ctdb_rec_data_old *r, uint32_t *reqid,
+	struct ctdb_ltdb_header **header, TDB_DATA *data)
+{
+	if (r->datalen < sizeof(struct ctdb_ltdb_header)) {
+		return false;
+	}
+
+	*reqid = r->reqid;
+
+	data->dptr  = &r->data[r->keylen] + sizeof(struct ctdb_ltdb_header);
+	data->dsize = r->datalen - sizeof(struct ctdb_ltdb_header);
+
+	*header = (struct ctdb_ltdb_header *)&r->data[r->keylen];
+
+	return true;
+}
+
+/**
+ * CTDB transaction destructor
+ */
+static int db_ctdb_transaction_destructor(struct db_ctdb_transaction_handle *h)
+{
+	NTSTATUS status;
+
+	status = g_lock_unlock(h->ctx->lock_ctx,
+			       string_term_tdb_data(h->lock_name));
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0, ("g_lock_unlock failed for %s: %s\n", h->lock_name,
+			  nt_errstr(status)));
+		return -1;
+	}
+	return 0;
+}
+
+/**
+ * CTDB dbwrap API: transaction_start function
+ * starts a transaction on a persistent database
+ */
+static int db_ctdb_transaction_start(struct db_context *db)
+{
+	struct db_ctdb_transaction_handle *h;
+	NTSTATUS status;
+	struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
+							struct db_ctdb_ctx);
+
+	if (!db->persistent) {
+		DEBUG(0,("transactions not supported on non-persistent database 0x%08x\n", 
+			 ctx->db_id));
+		return -1;
+	}
+
+	if (ctx->transaction) {
+		ctx->transaction->nesting++;
+		DEBUG(5, (__location__ " transaction start on db 0x%08x: nesting %d -> %d\n",
+			  ctx->db_id, ctx->transaction->nesting - 1, ctx->transaction->nesting));
+		return 0;
+	}
+
+	h = talloc_zero(db, struct db_ctdb_transaction_handle);
+	if (h == NULL) {
+		DEBUG(0,(__location__ " oom for transaction handle\n"));
+		return -1;
+	}
+
+	h->ctx = ctx;
+
+	h->lock_name = talloc_asprintf(h, "transaction_db_0x%08x",
+				       (unsigned int)ctx->db_id);
+	if (h->lock_name == NULL) {
+		DEBUG(0, ("talloc_asprintf failed\n"));
+		TALLOC_FREE(h);
+		return -1;
+	}
+
+	/*
+	 * Wait a day, i.e. forever...
+	 */
+	status = g_lock_lock(ctx->lock_ctx, string_term_tdb_data(h->lock_name),
+			     G_LOCK_WRITE, timeval_set(86400, 0), NULL, NULL);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0, ("g_lock_lock failed: %s\n", nt_errstr(status)));
+		TALLOC_FREE(h);
+		return -1;
+	}
+
+	talloc_set_destructor(h, db_ctdb_transaction_destructor);
+
+	ctx->transaction = h;
+
+	DEBUG(5,(__location__ " transaction started on db 0x%08x\n", ctx->db_id));
+
+	return 0;
+}
+
+static bool parse_newest_in_marshall_buffer(
+	struct ctdb_marshall_buffer *buf, TDB_DATA key,
+	void (*parser)(TDB_DATA key, struct ctdb_ltdb_header *header,
+		       TDB_DATA data, void *private_data),
+	void *private_data)
+{
+	struct ctdb_rec_data_old *rec = NULL;
+	struct ctdb_ltdb_header *h = NULL;
+	TDB_DATA data;
+	uint32_t i;
+
+	if (buf == NULL) {
+		return false;
+	}
+
+	/*
+	 * Walk the list of records written during this
+	 * transaction. If we want to read one we have already
+	 * written, return the last written sample. Thus we do not do
+	 * a "break;" for the first hit, this record might have been
+	 * overwritten later.
+	 */
+
+	for (i=0; i<buf->count; i++) {
+		TDB_DATA tkey;
+		uint32_t reqid;
+
+		rec = db_ctdb_marshall_loop_next_key(buf, rec, &tkey);
+		if (rec == NULL) {
+			return false;
+		}
+
+		if (!tdb_data_equal(key, tkey)) {
+			continue;
+		}
+
+		if (!db_ctdb_marshall_buf_parse(rec, &reqid, &h, &data)) {
+			return false;
+		}
+	}
+
+	if (h == NULL) {
+		return false;
+	}
+
+	parser(key, h, data, private_data);
+
+	return true;
+}
+
+struct pull_newest_from_marshall_buffer_state {
+	struct ctdb_ltdb_header *pheader;
+	TALLOC_CTX *mem_ctx;
+	TDB_DATA *pdata;
+};
+
+static void pull_newest_from_marshall_buffer_parser(
+	TDB_DATA key, struct ctdb_ltdb_header *header,
+	TDB_DATA data, void *private_data)
+{
+	struct pull_newest_from_marshall_buffer_state *state =
+		(struct pull_newest_from_marshall_buffer_state *)private_data;
+
+	if (state->pheader != NULL) {
+		memcpy(state->pheader, header, sizeof(*state->pheader));
+	}
+	if (state->pdata != NULL) {
+		state->pdata->dsize = data.dsize;
+		state->pdata->dptr = (uint8_t *)talloc_memdup(
+			state->mem_ctx, data.dptr, data.dsize);
+	}
+}
+
+static bool pull_newest_from_marshall_buffer(struct ctdb_marshall_buffer *buf,
+					     TDB_DATA key,
+					     struct ctdb_ltdb_header *pheader,
+					     TALLOC_CTX *mem_ctx,
+					     TDB_DATA *pdata)
+{
+	struct pull_newest_from_marshall_buffer_state state;
+
+	state.pheader = pheader;
+	state.mem_ctx = mem_ctx;
+	state.pdata = pdata;
+
+	if (!parse_newest_in_marshall_buffer(
+		    buf, key, pull_newest_from_marshall_buffer_parser,
+		    &state)) {
+		return false;
+	}
+	if ((pdata != NULL) && (pdata->dsize != 0) && (pdata->dptr == NULL)) {
+		/* ENOMEM */
+		return false;
+	}
+	return true;
+}
+
+static NTSTATUS db_ctdb_storev_transaction(struct db_record *rec,
+					   const TDB_DATA *dbufs, int num_dbufs,
+					   int flag);
+static NTSTATUS db_ctdb_delete_transaction(struct db_record *rec);
+
+static struct db_record *db_ctdb_fetch_locked_transaction(struct db_ctdb_ctx *ctx,
+							  TALLOC_CTX *mem_ctx,
+							  TDB_DATA key)
+{
+	struct db_record *result;
+	TDB_DATA ctdb_data;
+
+	if (!(result = talloc(mem_ctx, struct db_record))) {
+		DEBUG(0, ("talloc failed\n"));
+		return NULL;
+	}
+
+	result->db = ctx->db;
+	result->private_data = ctx->transaction;
+
+	result->key.dsize = key.dsize;
+	result->key.dptr = (uint8_t *)talloc_memdup(result, key.dptr,
+						    key.dsize);
+	if (result->key.dptr == NULL) {
+		DEBUG(0, ("talloc failed\n"));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	result->storev = db_ctdb_storev_transaction;
+	result->delete_rec = db_ctdb_delete_transaction;
+
+	if (ctx->transaction == NULL) {
+		DEBUG(0, ("no transaction available\n"));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+	if (pull_newest_from_marshall_buffer(ctx->transaction->m_write, key,
+					     NULL, result, &result->value)) {
+		result->value_valid = true;
+		return result;
+	}
+
+	ctdb_data = tdb_fetch(ctx->wtdb->tdb, key);
+	if (ctdb_data.dptr == NULL) {
+		/* create the record */
+		result->value = tdb_null;
+		result->value_valid = true;
+		return result;
+	}
+
+	result->value.dsize = ctdb_data.dsize - sizeof(struct ctdb_ltdb_header);
+	result->value.dptr = NULL;
+
+	if ((result->value.dsize != 0)
+	    && !(result->value.dptr = (uint8_t *)talloc_memdup(
+			 result, ctdb_data.dptr + sizeof(struct ctdb_ltdb_header),
+			 result->value.dsize))) {
+		DEBUG(0, ("talloc failed\n"));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+	result->value_valid = true;
+
+	SAFE_FREE(ctdb_data.dptr);
+
+	return result;
+}
+
+static int db_ctdb_record_destructor(struct db_record **recp)
+{
+	struct db_record *rec = talloc_get_type_abort(*recp, struct db_record);
+	struct db_ctdb_transaction_handle *h = talloc_get_type_abort(
+		rec->private_data, struct db_ctdb_transaction_handle);
+	int ret = h->ctx->db->transaction_commit(h->ctx->db);
+	if (ret != 0) {
+		DEBUG(0,(__location__ " transaction_commit failed\n"));
+	}
+	return 0;
+}
+
+/*
+  auto-create a transaction for persistent databases
+ */
+static struct db_record *db_ctdb_fetch_locked_persistent(struct db_ctdb_ctx *ctx,
+							 TALLOC_CTX *mem_ctx,
+							 TDB_DATA key)
+{
+	int res;
+	struct db_record *rec, **recp;
+
+	res = db_ctdb_transaction_start(ctx->db);
+	if (res == -1) {
+		return NULL;
+	}
+
+	rec = db_ctdb_fetch_locked_transaction(ctx, mem_ctx, key);
+	if (rec == NULL) {
+		ctx->db->transaction_cancel(ctx->db);
+		return NULL;
+	}
+
+	/* destroy this transaction when we release the lock */
+	recp = talloc(rec, struct db_record *);
+	if (recp == NULL) {
+		ctx->db->transaction_cancel(ctx->db);
+		talloc_free(rec);
+		return NULL;
+	}
+	*recp = rec;
+	talloc_set_destructor(recp, db_ctdb_record_destructor);
+	return rec;
+}
+
+
+/*
+  stores a record inside a transaction
+ */
+static NTSTATUS db_ctdb_transaction_store(struct db_ctdb_transaction_handle *h,
+					  TDB_DATA key, TDB_DATA data)
+{
+	TALLOC_CTX *tmp_ctx = talloc_new(h);
+	TDB_DATA rec;
+	struct ctdb_ltdb_header header;
+
+	ZERO_STRUCT(header);
+
+	/* we need the header so we can update the RSN */
+
+	if (!pull_newest_from_marshall_buffer(h->m_write, key, &header,
+					      NULL, NULL)) {
+
+		rec = tdb_fetch(h->ctx->wtdb->tdb, key);
+
+		if (rec.dptr != NULL) {
+			memcpy(&header, rec.dptr,
+			       sizeof(struct ctdb_ltdb_header));
+			rec.dsize -= sizeof(struct ctdb_ltdb_header);
+
+			/*
+			 * a special case, we are writing the same
+			 * data that is there now
+			 */
+			if (data.dsize == rec.dsize &&
+			    memcmp(data.dptr,
+				   rec.dptr + sizeof(struct ctdb_ltdb_header),
+				   data.dsize) == 0) {
+				SAFE_FREE(rec.dptr);
+				talloc_free(tmp_ctx);
+				return NT_STATUS_OK;
+			}
+		}
+		SAFE_FREE(rec.dptr);
+	}
+
+	header.dmaster = get_my_vnn();
+	header.rsn++;
+
+	h->m_write = db_ctdb_marshall_add(h, h->m_write, h->ctx->db_id, 0, key, &header, data);
+	if (h->m_write == NULL) {
+		DEBUG(0,(__location__ " Failed to add to marshalling record\n"));
+		talloc_free(tmp_ctx);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	talloc_free(tmp_ctx);
+	return NT_STATUS_OK;
+}
+
+
+/* 
+   a record store inside a transaction
+ */
+static NTSTATUS db_ctdb_storev_transaction(
+	struct db_record *rec, const TDB_DATA *dbufs, int num_dbufs, int flag)
+{
+	struct db_ctdb_transaction_handle *h = talloc_get_type_abort(
+		rec->private_data, struct db_ctdb_transaction_handle);
+	NTSTATUS status;
+	TDB_DATA data = {0};
+
+	status = dbwrap_merge_dbufs(&data, rec, dbufs, num_dbufs);
+	if (!NT_STATUS_IS_OK(status)) {
+		return status;
+	}
+
+	status = db_ctdb_transaction_store(h, rec->key, data);
+
+	TALLOC_FREE(data.dptr);
+
+	return status;
+}
+
+/*
+   a record delete inside a transaction
+ */
+static NTSTATUS db_ctdb_delete_transaction(struct db_record *rec)
+{
+	struct db_ctdb_transaction_handle *h = talloc_get_type_abort(
+		rec->private_data, struct db_ctdb_transaction_handle);
+	NTSTATUS status;
+
+	status =  db_ctdb_transaction_store(h, rec->key, tdb_null);
+	return status;
+}
+
+static void db_ctdb_fetch_db_seqnum_parser(
+	TDB_DATA key, struct ctdb_ltdb_header *header,
+	TDB_DATA data, void *private_data)
+{
+	uint64_t *seqnum = (uint64_t *)private_data;
+
+	if (data.dsize != sizeof(uint64_t)) {
+		*seqnum = 0;
+		return;
+	}
+	memcpy(seqnum, data.dptr, sizeof(*seqnum));
+}
+
+/**
+ * Fetch the db sequence number of a persistent db directly from the db.
+ */
+static NTSTATUS db_ctdb_fetch_db_seqnum_from_db(struct db_ctdb_ctx *db,
+						uint64_t *seqnum)
+{
+	NTSTATUS status;
+	TDB_DATA key;
+
+	if (seqnum == NULL) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	key = string_term_tdb_data(CTDB_DB_SEQNUM_KEY);
+
+	status = db_ctdb_ltdb_parse(
+		db, key, db_ctdb_fetch_db_seqnum_parser, seqnum);
+
+	if (NT_STATUS_IS_OK(status)) {
+		return NT_STATUS_OK;
+	}
+	if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) {
+		*seqnum = 0;
+		return NT_STATUS_OK;
+	}
+	return status;
+}
+
+/**
+ * Store the database sequence number inside a transaction.
+ */
+static NTSTATUS db_ctdb_store_db_seqnum(struct db_ctdb_transaction_handle *h,
+					uint64_t seqnum)
+{
+	NTSTATUS status;
+	TDB_DATA key = string_term_tdb_data(CTDB_DB_SEQNUM_KEY);
+	TDB_DATA data = { .dptr=(uint8_t *)&seqnum, .dsize=sizeof(seqnum) };
+
+	status = db_ctdb_transaction_store(h, key, data);
+
+	return status;
+}
+
+/*
+  commit a transaction
+ */
+static int db_ctdb_transaction_commit(struct db_context *db)
+{
+	struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
+							struct db_ctdb_ctx);
+	NTSTATUS rets;
+	int32_t status;
+	struct db_ctdb_transaction_handle *h = ctx->transaction;
+	uint64_t old_seqnum, new_seqnum;
+	int ret;
+
+	if (h == NULL) {
+		DEBUG(0,(__location__ " transaction commit with no open transaction on db 0x%08x\n", ctx->db_id));
+		return -1;
+	}
+
+	if (h->nested_cancel) {
+		db->transaction_cancel(db);
+		DEBUG(5,(__location__ " Failed transaction commit after nested cancel\n"));
+		return -1;
+	}
+
+	if (h->nesting != 0) {
+		h->nesting--;
+		DEBUG(5, (__location__ " transaction commit on db 0x%08x: nesting %d -> %d\n",
+			  ctx->db_id, ctx->transaction->nesting + 1, ctx->transaction->nesting));
+		return 0;
+	}
+
+	if (h->m_write == NULL) {
+		/*
+		 * No changes were made, so don't change the seqnum,
+		 * don't push to other node, just exit with success.
+		 */
+		ret = 0;
+		goto done;
+	}
+
+	DEBUG(5,(__location__ " transaction commit on db 0x%08x\n", ctx->db_id));
+
+	/*
+	 * As the last db action before committing, bump the database sequence
+	 * number. Note that this undoes all changes to the seqnum records
+	 * performed under the transaction. This record is not meant to be
+	 * modified by user interaction. It is for internal use only...
+	 */
+	rets = db_ctdb_fetch_db_seqnum_from_db(ctx, &old_seqnum);
+	if (!NT_STATUS_IS_OK(rets)) {
+		DEBUG(1, (__location__ " failed to fetch the db sequence number "
+			  "in transaction commit on db 0x%08x\n", ctx->db_id));
+		ret = -1;
+		goto done;
+	}
+
+	new_seqnum = old_seqnum + 1;
+
+	rets = db_ctdb_store_db_seqnum(h, new_seqnum);
+	if (!NT_STATUS_IS_OK(rets)) {
+		DEBUG(1, (__location__ "failed to store the db sequence number "
+			  " in transaction commit on db 0x%08x\n", ctx->db_id));
+		ret = -1;
+		goto done;
+	}
+
+again:
+	/* tell ctdbd to commit to the other nodes */
+	ret = ctdbd_control_local(messaging_ctdb_connection(),
+				  CTDB_CONTROL_TRANS3_COMMIT,
+				  h->ctx->db_id, 0,
+				  db_ctdb_marshall_finish(h->m_write),
+				  NULL, NULL, &status);
+	if ((ret != 0) || status != 0) {
+		/*
+		 * The TRANS3_COMMIT control should only possibly fail when a
+		 * recovery has been running concurrently. In any case, the db
+		 * will be the same on all nodes, either the new copy or the
+		 * old copy.  This can be detected by comparing the old and new
+		 * local sequence numbers.
+		 */
+		rets = db_ctdb_fetch_db_seqnum_from_db(ctx, &new_seqnum);
+		if (!NT_STATUS_IS_OK(rets)) {
+			DEBUG(1, (__location__ " failed to refetch db sequence "
+				  "number after failed TRANS3_COMMIT\n"));
+			ret = -1;
+			goto done;
+		}
+
+		if (new_seqnum == old_seqnum) {
+			/* Recovery prevented all our changes: retry. */
+			goto again;
+		}
+		if (new_seqnum != (old_seqnum + 1)) {
+			DEBUG(0, (__location__ " ERROR: new_seqnum[%lu] != "
+				  "old_seqnum[%lu] + (0 or 1) after failed "
+				  "TRANS3_COMMIT - this should not happen!\n",
+				  (unsigned long)new_seqnum,
+				  (unsigned long)old_seqnum));
+			ret = -1;
+			goto done;
+		}
+		/*
+		 * Recovery propagated our changes to all nodes, completing
+		 * our commit for us - succeed.
+		 */
+	}
+
+	ret = 0;
+
+done:
+	h->ctx->transaction = NULL;
+	talloc_free(h);
+	return ret;
+}
+
+
+/*
+  cancel a transaction
+ */
+static int db_ctdb_transaction_cancel(struct db_context *db)
+{
+	struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
+							struct db_ctdb_ctx);
+	struct db_ctdb_transaction_handle *h = ctx->transaction;
+
+	if (h == NULL) {
+		DEBUG(0,(__location__ " transaction cancel with no open transaction on db 0x%08x\n", ctx->db_id));
+		return -1;
+	}
+
+	if (h->nesting != 0) {
+		h->nesting--;
+		h->nested_cancel = true;
+		DEBUG(5, (__location__ " transaction cancel on db 0x%08x: nesting %d -> %d\n",
+			  ctx->db_id, ctx->transaction->nesting + 1, ctx->transaction->nesting));
+		return 0;
+	}
+
+	DEBUG(5,(__location__ " Cancel transaction on db 0x%08x\n", ctx->db_id));
+
+	ctx->transaction = NULL;
+	talloc_free(h);
+	return 0;
+}
+
+
+static NTSTATUS db_ctdb_storev(struct db_record *rec,
+			       const TDB_DATA *dbufs, int num_dbufs, int flag)
+{
+	struct db_ctdb_rec *crec = talloc_get_type_abort(
+		rec->private_data, struct db_ctdb_rec);
+	NTSTATUS status;
+
+	status = db_ctdb_ltdb_store(crec->ctdb_ctx, rec->key, &(crec->header),
+				    dbufs, num_dbufs);
+	return status;
+}
+
+
+
+static NTSTATUS db_ctdb_send_schedule_for_deletion(struct db_record *rec)
+{
+	NTSTATUS status = NT_STATUS_OK;
+	int ret;
+	struct ctdb_control_schedule_for_deletion *dd;
+	TDB_DATA indata;
+	int32_t cstatus;
+	struct db_ctdb_rec *crec = talloc_get_type_abort(
+		rec->private_data, struct db_ctdb_rec);
+	struct db_ctdb_ctx *ctx = crec->ctdb_ctx;
+
+	indata.dsize = offsetof(struct ctdb_control_schedule_for_deletion, key) + rec->key.dsize;
+	indata.dptr = talloc_zero_array(crec, uint8_t, indata.dsize);
+	if (indata.dptr == NULL) {
+		DEBUG(0, (__location__ " talloc failed!\n"));
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	dd = (struct ctdb_control_schedule_for_deletion *)(void *)indata.dptr;
+	dd->db_id = ctx->db_id;
+	dd->hdr = crec->header;
+	dd->keylen = rec->key.dsize;
+	memcpy(dd->key, rec->key.dptr, rec->key.dsize);
+
+	ret = ctdbd_control_local(messaging_ctdb_connection(),
+				  CTDB_CONTROL_SCHEDULE_FOR_DELETION,
+				  crec->ctdb_ctx->db_id,
+				  CTDB_CTRL_FLAG_NOREPLY, /* flags */
+				  indata,
+				  NULL, /* mem_ctx */
+				  NULL, /* outdata */
+				  &cstatus);
+	talloc_free(indata.dptr);
+
+	if ((ret != 0) || cstatus != 0) {
+		DEBUG(1, (__location__ " Error sending local control "
+			  "SCHEDULE_FOR_DELETION: %s, cstatus = %"PRIi32"\n",
+			  strerror(ret), cstatus));
+		if (ret != 0) {
+			status = map_nt_error_from_unix(ret);
+		} else {
+			status = NT_STATUS_UNSUCCESSFUL;
+		}
+	}
+
+	return status;
+}
+
+static NTSTATUS db_ctdb_delete(struct db_record *rec)
+{
+	NTSTATUS status;
+
+	/*
+	 * We have to store the header with empty data. TODO: Fix the
+	 * tdb-level cleanup
+	 */
+
+	status = db_ctdb_storev(rec, &tdb_null, 1, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		return status;
+	}
+
+	status = db_ctdb_send_schedule_for_deletion(rec);
+	return status;
+}
+
+static int db_ctdb_record_destr(struct db_record* data)
+{
+	struct db_ctdb_rec *crec = talloc_get_type_abort(
+		data->private_data, struct db_ctdb_rec);
+	int threshold;
+	int ret;
+	struct timeval before;
+	double timediff;
+
+	DEBUG(10, (DEBUGLEVEL > 10
+		   ? "Unlocking db %u key %s\n"
+		   : "Unlocking db %u key %.20s\n",
+		   (int)crec->ctdb_ctx->db_id,
+		   hex_encode_talloc(data, (unsigned char *)data->key.dptr,
+			      data->key.dsize)));
+
+	before = timeval_current();
+
+	ret = tdb_chainunlock(crec->ctdb_ctx->wtdb->tdb, data->key);
+
+	timediff = timeval_elapsed(&before);
+	timediff *= 1000;	/* get us milliseconds */
+
+	if (timediff > crec->ctdb_ctx->warn_unlock_msecs) {
+		char *key;
+		key = hex_encode_talloc(talloc_tos(),
+					(unsigned char *)data->key.dptr,
+					data->key.dsize);
+		DEBUG(0, ("tdb_chainunlock on db %s, key %s took %f milliseconds\n",
+			  tdb_name(crec->ctdb_ctx->wtdb->tdb), key,
+			  timediff));
+		TALLOC_FREE(key);
+	}
+
+	if (ret != 0) {
+		DEBUG(0, ("tdb_chainunlock failed\n"));
+		return -1;
+	}
+
+	threshold = crec->ctdb_ctx->warn_locktime_msecs;
+	if (threshold != 0) {
+		timediff = timeval_elapsed(&crec->lock_time) * 1000;
+		if (timediff > threshold) {
+			const char *key;
+
+			key = hex_encode_talloc(data,
+						(unsigned char *)data->key.dptr,
+						data->key.dsize);
+			DEBUG(0, ("Held tdb lock on db %s, key %s "
+				  "%f milliseconds\n",
+				  tdb_name(crec->ctdb_ctx->wtdb->tdb),
+				  key, timediff));
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * Check whether we have a valid local copy of the given record,
+ * either for reading or for writing.
+ */
+static bool db_ctdb_can_use_local_hdr(const struct ctdb_ltdb_header *hdr,
+				      uint32_t my_vnn, bool read_only)
+{
+	if (hdr->dmaster != my_vnn) {
+		/* If we're not dmaster, it must be r/o copy. */
+		return read_only && (hdr->flags & CTDB_REC_RO_HAVE_READONLY);
+	}
+
+	/*
+	 * If we want write access, no one may have r/o copies.
+	 */
+	return read_only || !(hdr->flags & CTDB_REC_RO_HAVE_DELEGATIONS);
+}
+
+static bool db_ctdb_can_use_local_copy(TDB_DATA ctdb_data, uint32_t my_vnn,
+				       bool read_only)
+{
+	if (ctdb_data.dptr == NULL) {
+		return false;
+	}
+
+	if (ctdb_data.dsize < sizeof(struct ctdb_ltdb_header)) {
+		return false;
+	}
+
+	return db_ctdb_can_use_local_hdr(
+		(struct ctdb_ltdb_header *)ctdb_data.dptr, my_vnn, read_only);
+}
+
+static struct db_record *fetch_locked_internal(struct db_ctdb_ctx *ctx,
+					       TALLOC_CTX *mem_ctx,
+					       TDB_DATA key)
+{
+	struct db_record *result;
+	struct db_ctdb_rec *crec;
+	TDB_DATA ctdb_data;
+	int migrate_attempts;
+	struct timeval migrate_start;
+	struct timeval chainlock_start;
+	struct timeval ctdb_start_time;
+	double chainlock_time = 0;
+	double ctdb_time = 0;
+	int duration_msecs;
+	int lockret;
+	int ret;
+
+	if (!(result = talloc(mem_ctx, struct db_record))) {
+		DEBUG(0, ("talloc failed\n"));
+		return NULL;
+	}
+
+	if (!(crec = talloc_zero(result, struct db_ctdb_rec))) {
+		DEBUG(0, ("talloc failed\n"));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	result->db = ctx->db;
+	result->private_data = (void *)crec;
+	crec->ctdb_ctx = ctx;
+
+	result->key.dsize = key.dsize;
+	result->key.dptr = (uint8_t *)talloc_memdup(result, key.dptr,
+						    key.dsize);
+	if (result->key.dptr == NULL) {
+		DEBUG(0, ("talloc failed\n"));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	migrate_attempts = 0;
+	GetTimeOfDay(&migrate_start);
+
+	/*
+	 * Do a blocking lock on the record
+	 */
+again:
+
+	if (DEBUGLEVEL >= 10) {
+		char *keystr = hex_encode_talloc(result, key.dptr, key.dsize);
+		DEBUG(10, (DEBUGLEVEL > 10
+			   ? "Locking db %u key %s\n"
+			   : "Locking db %u key %.20s\n",
+			   (int)crec->ctdb_ctx->db_id, keystr));
+		TALLOC_FREE(keystr);
+	}
+
+	GetTimeOfDay(&chainlock_start);
+	lockret = tdb_chainlock(ctx->wtdb->tdb, key);
+	chainlock_time += timeval_elapsed(&chainlock_start);
+
+	if (lockret != 0) {
+		DEBUG(3, ("tdb_chainlock failed\n"));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	result->storev = db_ctdb_storev;
+	result->delete_rec = db_ctdb_delete;
+	talloc_set_destructor(result, db_ctdb_record_destr);
+
+	ctdb_data = tdb_fetch(ctx->wtdb->tdb, key);
+
+	/*
+	 * See if we have a valid record and we are the dmaster. If so, we can
+	 * take the shortcut and just return it.
+	 */
+
+	if (!db_ctdb_can_use_local_copy(ctdb_data, get_my_vnn(), false)) {
+		SAFE_FREE(ctdb_data.dptr);
+		tdb_chainunlock(ctx->wtdb->tdb, key);
+		talloc_set_destructor(result, NULL);
+
+		migrate_attempts += 1;
+
+		DEBUG(10, ("ctdb_data.dptr = %p, dmaster = %"PRIu32" "
+			   "(%"PRIu32") %"PRIu32"\n",
+			   ctdb_data.dptr, ctdb_data.dptr ?
+			   ((struct ctdb_ltdb_header *)ctdb_data.dptr)->dmaster :
+			   UINT32_MAX,
+			   get_my_vnn(),
+			   ctdb_data.dptr ?
+			   ((struct ctdb_ltdb_header *)ctdb_data.dptr)->flags : 0));
+
+		GetTimeOfDay(&ctdb_start_time);
+		ret = ctdbd_migrate(messaging_ctdb_connection(), ctx->db_id,
+				    key);
+		ctdb_time += timeval_elapsed(&ctdb_start_time);
+
+		if (ret != 0) {
+			DEBUG(5, ("ctdbd_migrate failed: %s\n",
+				  strerror(ret)));
+			TALLOC_FREE(result);
+			return NULL;
+		}
+		/* now its migrated, try again */
+		goto again;
+	}
+
+	{
+		double duration;
+		duration = timeval_elapsed(&migrate_start);
+
+		/*
+		 * Convert the duration to milliseconds to avoid a
+		 * floating-point division of
+		 * lp_parm_int("migrate_duration") by 1000.
+		 */
+		duration_msecs = duration * 1000;
+	}
+
+	if ((migrate_attempts > ctx->warn_migrate_attempts) ||
+	    (duration_msecs > ctx->warn_migrate_msecs)) {
+		int chain = 0;
+
+		if (tdb_get_flags(ctx->wtdb->tdb) & TDB_INCOMPATIBLE_HASH) {
+			chain = tdb_jenkins_hash(&key) %
+				tdb_hash_size(ctx->wtdb->tdb);
+		}
+
+		DEBUG(0, ("db_ctdb_fetch_locked for %s key %s, chain %d "
+			  "needed %d attempts, %d milliseconds, "
+			  "chainlock: %f ms, CTDB %f ms\n",
+			  tdb_name(ctx->wtdb->tdb),
+			  hex_encode_talloc(talloc_tos(),
+					    (unsigned char *)key.dptr,
+					    key.dsize),
+			  chain,
+			  migrate_attempts, duration_msecs,
+			  chainlock_time * 1000.0,
+			  ctdb_time * 1000.0));
+	}
+
+	GetTimeOfDay(&crec->lock_time);
+
+	memcpy(&crec->header, ctdb_data.dptr, sizeof(crec->header));
+
+	result->value.dsize = ctdb_data.dsize - sizeof(crec->header);
+	result->value.dptr = NULL;
+
+	if (result->value.dsize != 0) {
+		result->value.dptr = talloc_memdup(
+			result, ctdb_data.dptr + sizeof(crec->header),
+			result->value.dsize);
+		if (result->value.dptr == NULL) {
+			DBG_ERR("talloc failed\n");
+			TALLOC_FREE(result);
+			return NULL;
+		}
+	}
+	result->value_valid = true;
+
+	SAFE_FREE(ctdb_data.dptr);
+
+	return result;
+}
+
+static struct db_record *db_ctdb_fetch_locked(struct db_context *db,
+					      TALLOC_CTX *mem_ctx,
+					      TDB_DATA key)
+{
+	struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
+							struct db_ctdb_ctx);
+
+	if (ctx->transaction != NULL) {
+		return db_ctdb_fetch_locked_transaction(ctx, mem_ctx, key);
+	}
+
+	if (db->persistent) {
+		return db_ctdb_fetch_locked_persistent(ctx, mem_ctx, key);
+	}
+
+	return fetch_locked_internal(ctx, mem_ctx, key);
+}
+
+struct db_ctdb_parse_record_state {
+	void (*parser)(TDB_DATA key, TDB_DATA data, void *private_data);
+	void *private_data;
+	uint32_t my_vnn;
+	bool ask_for_readonly_copy;
+	bool done;
+	bool empty_record;
+};
+
+static void db_ctdb_parse_record_parser(
+	TDB_DATA key, struct ctdb_ltdb_header *header,
+	TDB_DATA data, void *private_data)
+{
+	struct db_ctdb_parse_record_state *state =
+		(struct db_ctdb_parse_record_state *)private_data;
+	state->parser(key, data, state->private_data);
+}
+
+static void db_ctdb_parse_record_parser_nonpersistent(
+	TDB_DATA key, struct ctdb_ltdb_header *header,
+	TDB_DATA data, void *private_data)
+{
+	struct db_ctdb_parse_record_state *state =
+		(struct db_ctdb_parse_record_state *)private_data;
+
+	if (db_ctdb_can_use_local_hdr(header, state->my_vnn, true)) {
+		/*
+		 * A record consisting only of the ctdb header can be
+		 * a validly created empty record or a tombstone
+		 * record of a deleted record (not vacuumed yet). Mark
+		 * it accordingly.
+		 */
+		state->empty_record = (data.dsize == 0);
+		if (!state->empty_record) {
+			state->parser(key, data, state->private_data);
+		}
+		state->done = true;
+	} else {
+		/*
+		 * We found something in the db, so it seems that this record,
+		 * while not usable locally right now, is popular. Ask for a
+		 * R/O copy.
+		 */
+		state->ask_for_readonly_copy = true;
+	}
+}
+
+static NTSTATUS db_ctdb_try_parse_local_record(struct db_ctdb_ctx *ctx,
+					       TDB_DATA key,
+					       struct db_ctdb_parse_record_state *state)
+{
+	NTSTATUS status;
+
+	if (ctx->transaction != NULL) {
+		struct db_ctdb_transaction_handle *h = ctx->transaction;
+		bool found;
+
+		/*
+		 * Transactions only happen for persistent db's.
+		 */
+
+		found = parse_newest_in_marshall_buffer(
+			h->m_write, key, db_ctdb_parse_record_parser, state);
+
+		if (found) {
+			return NT_STATUS_OK;
+		}
+	}
+
+	if (ctx->db->persistent) {
+		/*
+		 * Persistent db, but not found in the transaction buffer
+		 */
+		return db_ctdb_ltdb_parse(
+			ctx, key, db_ctdb_parse_record_parser, state);
+	}
+
+	state->done = false;
+	state->ask_for_readonly_copy = false;
+
+	status = db_ctdb_ltdb_parse(
+		ctx, key, db_ctdb_parse_record_parser_nonpersistent, state);
+	if (NT_STATUS_IS_OK(status) && state->done) {
+		if (state->empty_record) {
+			/*
+			 * We know authoritatively, that this is an empty
+			 * record. Since ctdb does not distinguish between empty
+			 * and deleted records, this can be a record stored as
+			 * empty or a not-yet-vacuumed tombstone record of a
+			 * deleted record. Now Samba right now can live without
+			 * empty records, so we can safely report this record
+			 * as non-existing.
+			 *
+			 * See bugs 10008 and 12005.
+			 */
+			return NT_STATUS_NOT_FOUND;
+		}
+		return NT_STATUS_OK;
+	}
+
+	return NT_STATUS_MORE_PROCESSING_REQUIRED;
+}
+
+static NTSTATUS db_ctdb_parse_record(struct db_context *db, TDB_DATA key,
+				     void (*parser)(TDB_DATA key,
+						    TDB_DATA data,
+						    void *private_data),
+				     void *private_data)
+{
+	struct db_ctdb_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_ctdb_ctx);
+	struct db_ctdb_parse_record_state state;
+	NTSTATUS status;
+	int ret;
+
+	state.parser = parser;
+	state.private_data = private_data;
+	state.my_vnn = get_my_vnn();
+	state.empty_record = false;
+
+	status = db_ctdb_try_parse_local_record(ctx, key, &state);
+	if (!NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
+		return status;
+	}
+
+	ret = ctdbd_parse(messaging_ctdb_connection(), ctx->db_id, key,
+			  state.ask_for_readonly_copy, parser, private_data);
+	if (ret != 0) {
+		if (ret == ENOENT) {
+			/*
+			 * This maps to
+			 * NT_STATUS_OBJECT_NAME_NOT_FOUND. Our upper
+			 * layers expect NT_STATUS_NOT_FOUND for "no
+			 * record around". We need to convert dbwrap
+			 * to 0/errno away from NTSTATUS ... :-)
+			 */
+			return NT_STATUS_NOT_FOUND;
+		}
+		return map_nt_error_from_unix(ret);
+	}
+	return NT_STATUS_OK;
+}
+
+static void db_ctdb_parse_record_done(struct tevent_req *subreq);
+
+static struct tevent_req *db_ctdb_parse_record_send(
+	TALLOC_CTX *mem_ctx,
+	struct tevent_context *ev,
+	struct db_context *db,
+	TDB_DATA key,
+	void (*parser)(TDB_DATA key,
+		       TDB_DATA data,
+		       void *private_data),
+	void *private_data,
+	enum dbwrap_req_state *req_state)
+{
+	struct db_ctdb_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_ctdb_ctx);
+	struct tevent_req *req = NULL;
+	struct tevent_req *subreq = NULL;
+	struct db_ctdb_parse_record_state *state = NULL;
+	NTSTATUS status;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct db_ctdb_parse_record_state);
+	if (req == NULL) {
+		*req_state = DBWRAP_REQ_ERROR;
+		return NULL;
+
+	}
+
+	*state = (struct db_ctdb_parse_record_state) {
+		.parser = parser,
+		.private_data = private_data,
+		.my_vnn = get_my_vnn(),
+		.empty_record = false,
+	};
+
+	status = db_ctdb_try_parse_local_record(ctx, key, state);
+	if (!NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
+		if (tevent_req_nterror(req, status)) {
+			*req_state = DBWRAP_REQ_ERROR;
+			return tevent_req_post(req, ev);
+		}
+		*req_state = DBWRAP_REQ_DONE;
+		tevent_req_done(req);
+		return tevent_req_post(req, ev);
+	}
+
+	subreq = ctdbd_parse_send(state,
+				  ev,
+				  ctdb_async_ctx.async_conn,
+				  ctx->db_id,
+				  key,
+				  state->ask_for_readonly_copy,
+				  parser,
+				  private_data,
+				  req_state);
+	if (tevent_req_nomem(subreq, req)) {
+		*req_state = DBWRAP_REQ_ERROR;
+		return tevent_req_post(req, ev);
+	}
+	tevent_req_set_callback(subreq, db_ctdb_parse_record_done, req);
+
+	return req;
+}
+
+static void db_ctdb_parse_record_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(
+		subreq, struct tevent_req);
+	int ret;
+
+	ret = ctdbd_parse_recv(subreq);
+	TALLOC_FREE(subreq);
+	if (ret != 0) {
+		if (ret == ENOENT) {
+			/*
+			 * This maps to NT_STATUS_OBJECT_NAME_NOT_FOUND. Our
+			 * upper layers expect NT_STATUS_NOT_FOUND for "no
+			 * record around". We need to convert dbwrap to 0/errno
+			 * away from NTSTATUS ... :-)
+			 */
+			tevent_req_nterror(req, NT_STATUS_NOT_FOUND);
+			return;
+		}
+		tevent_req_nterror(req, map_nt_error_from_unix(ret));
+		return;
+	}
+
+	tevent_req_done(req);
+	return;
+}
+
+static NTSTATUS db_ctdb_parse_record_recv(struct tevent_req *req)
+{
+	return tevent_req_simple_recv_ntstatus(req);
+}
+
+struct traverse_state {
+	struct db_context *db;
+	int (*fn)(struct db_record *rec, void *private_data);
+	void *private_data;
+	int count;
+};
+
+static void traverse_callback(TDB_DATA key, TDB_DATA data, void *private_data)
+{
+	struct traverse_state *state = (struct traverse_state *)private_data;
+	struct db_record *rec = NULL;
+	TALLOC_CTX *tmp_ctx = NULL;
+
+	tmp_ctx = talloc_new(state->db);
+	if (tmp_ctx == NULL) {
+		DBG_ERR("talloc_new failed\n");
+		return;
+	}
+
+	/* we have to give them a locked record to prevent races */
+	rec = db_ctdb_fetch_locked(state->db, tmp_ctx, key);
+	if (rec != NULL && rec->value.dsize > 0) {
+		state->fn(rec, state->private_data);
+		state->count++;
+	}
+	talloc_free(tmp_ctx);
+}
+
+static int traverse_persistent_callback(TDB_CONTEXT *tdb, TDB_DATA kbuf, TDB_DATA dbuf,
+					void *private_data)
+{
+	struct traverse_state *state = (struct traverse_state *)private_data;
+	struct db_record *rec;
+	TALLOC_CTX *tmp_ctx = talloc_new(state->db);
+	int ret = 0;
+
+	/*
+	 * Skip the __db_sequence_number__ key:
+	 * This is used for persistent transactions internally.
+	 */
+	if (kbuf.dsize == strlen(CTDB_DB_SEQNUM_KEY) + 1 &&
+	    strcmp((const char*)kbuf.dptr, CTDB_DB_SEQNUM_KEY) == 0)
+	{
+		goto done;
+	}
+
+	/* we have to give them a locked record to prevent races */
+	rec = db_ctdb_fetch_locked(state->db, tmp_ctx, kbuf);
+	if (rec && rec->value.dsize > 0) {
+		ret = state->fn(rec, state->private_data);
+	}
+
+done:
+	talloc_free(tmp_ctx);
+	return ret;
+}
+
+/* wrapper to use traverse_persistent_callback with dbwrap */
+static int traverse_persistent_callback_dbwrap(struct db_record *rec, void* data)
+{
+	return traverse_persistent_callback(NULL, rec->key, rec->value, data);
+}
+
+static int db_ctdbd_traverse(uint32_t db_id,
+			     void (*fn)(TDB_DATA key, TDB_DATA data,
+					void *private_data),
+			     void *private_data)
+{
+	struct ctdbd_connection *conn;
+	int ret;
+
+	become_root();
+	ret = ctdbd_init_connection(talloc_tos(), lp_ctdbd_socket(),
+				    lp_ctdb_timeout(), &conn);
+	unbecome_root();
+	if (ret != 0) {
+		DBG_WARNING("ctdbd_init_connection failed: %s\n",
+			    strerror(ret));
+		return ret;
+	}
+
+	ret = ctdbd_traverse(conn, db_id, fn, private_data);
+	TALLOC_FREE(conn);
+
+	if (ret != 0) {
+		DBG_WARNING("ctdbd_traverse failed: %s\n",
+			    strerror(ret));
+		return ret;
+	}
+
+	return 0;
+}
+
+
+static int db_ctdb_traverse(struct db_context *db,
+			    int (*fn)(struct db_record *rec,
+				      void *private_data),
+			    void *private_data)
+{
+	int ret;
+        struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
+                                                        struct db_ctdb_ctx);
+	struct traverse_state state;
+
+	state = (struct traverse_state) {
+		.db = db,
+		.fn = fn,
+		.private_data = private_data,
+	};
+
+	if (db->persistent) {
+		struct tdb_context *ltdb = ctx->wtdb->tdb;
+
+		/* for persistent databases we don't need to do a ctdb traverse,
+		   we can do a faster local traverse */
+		ret = tdb_traverse(ltdb, traverse_persistent_callback, &state);
+		if (ret < 0) {
+			return ret;
+		}
+		if (ctx->transaction && ctx->transaction->m_write) {
+			/*
+			 * we now have to handle keys not yet
+			 * present at transaction start
+			 */
+			struct db_context *newkeys = db_open_rbt(talloc_tos());
+			struct ctdb_marshall_buffer *mbuf = ctx->transaction->m_write;
+			struct ctdb_rec_data_old *rec=NULL;
+			uint32_t i;
+			int count = 0;
+			NTSTATUS status;
+
+			if (newkeys == NULL) {
+				return -1;
+			}
+
+			for (i=0; i<mbuf->count; i++) {
+				TDB_DATA key;
+				rec = db_ctdb_marshall_loop_next_key(
+					mbuf, rec, &key);
+				SMB_ASSERT(rec != NULL);
+
+				if (!tdb_exists(ltdb, key)) {
+					dbwrap_store(newkeys, key, tdb_null, 0);
+				}
+			}
+			status = dbwrap_traverse(newkeys,
+						 traverse_persistent_callback_dbwrap,
+						 &state,
+						 &count);
+			talloc_free(newkeys);
+			if (!NT_STATUS_IS_OK(status)) {
+				return -1;
+			}
+			ret += count;
+		}
+		return ret;
+	}
+
+	ret = db_ctdbd_traverse(ctx->db_id, traverse_callback, &state);
+	if (ret != 0) {
+		return -1;
+	}
+	return state.count;
+}
+
+static NTSTATUS db_ctdb_storev_deny(struct db_record *rec,
+				    const TDB_DATA *dbufs, int num_dbufs, int flag)
+{
+	return NT_STATUS_MEDIA_WRITE_PROTECTED;
+}
+
+static NTSTATUS db_ctdb_delete_deny(struct db_record *rec)
+{
+	return NT_STATUS_MEDIA_WRITE_PROTECTED;
+}
+
+static void traverse_read_callback(TDB_DATA key, TDB_DATA data, void *private_data)
+{
+	struct traverse_state *state = (struct traverse_state *)private_data;
+	struct db_record rec;
+
+	ZERO_STRUCT(rec);
+	rec.db = state->db;
+	rec.key = key;
+	rec.value = data;
+	rec.storev = db_ctdb_storev_deny;
+	rec.delete_rec = db_ctdb_delete_deny;
+	rec.private_data = NULL;
+	rec.value_valid = true;
+	state->fn(&rec, state->private_data);
+	state->count++;
+}
+
+static int traverse_persistent_callback_read(TDB_CONTEXT *tdb, TDB_DATA kbuf, TDB_DATA dbuf,
+					void *private_data)
+{
+	struct traverse_state *state = (struct traverse_state *)private_data;
+	struct db_record rec;
+
+	/*
+	 * Skip the __db_sequence_number__ key:
+	 * This is used for persistent transactions internally.
+	 */
+	if (kbuf.dsize == strlen(CTDB_DB_SEQNUM_KEY) + 1 &&
+	    strcmp((const char*)kbuf.dptr, CTDB_DB_SEQNUM_KEY) == 0)
+	{
+		return 0;
+	}
+
+	ZERO_STRUCT(rec);
+	rec.db = state->db;
+	rec.key = kbuf;
+	rec.value = dbuf;
+	rec.value_valid = true;
+	rec.storev = db_ctdb_storev_deny;
+	rec.delete_rec = db_ctdb_delete_deny;
+	rec.private_data = NULL;
+
+	if (rec.value.dsize <= sizeof(struct ctdb_ltdb_header)) {
+		/* a deleted record */
+		return 0;
+	}
+	rec.value.dsize -= sizeof(struct ctdb_ltdb_header);
+	rec.value.dptr += sizeof(struct ctdb_ltdb_header);
+
+	state->count++;
+	return state->fn(&rec, state->private_data);
+}
+
+static int db_ctdb_traverse_read(struct db_context *db,
+				 int (*fn)(struct db_record *rec,
+					   void *private_data),
+				 void *private_data)
+{
+	int ret;
+        struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
+                                                        struct db_ctdb_ctx);
+	struct traverse_state state;
+
+	state = (struct traverse_state) {
+		.db = db,
+		.fn = fn,
+		.private_data = private_data,
+	};
+
+	if (db->persistent) {
+		/* for persistent databases we don't need to do a ctdb traverse,
+		   we can do a faster local traverse */
+		int nrecs;
+
+		nrecs = tdb_traverse_read(ctx->wtdb->tdb,
+					  traverse_persistent_callback_read,
+					  &state);
+		if (nrecs == -1) {
+			return -1;
+		}
+		return state.count;
+	}
+
+	ret = db_ctdbd_traverse(ctx->db_id, traverse_read_callback, &state);
+	if (ret != 0) {
+		return -1;
+	}
+	return state.count;
+}
+
+static int db_ctdb_get_seqnum(struct db_context *db)
+{
+        struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
+                                                        struct db_ctdb_ctx);
+	return tdb_get_seqnum(ctx->wtdb->tdb);
+}
+
+static size_t db_ctdb_id(struct db_context *db, uint8_t *id, size_t idlen)
+{
+	struct db_ctdb_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_ctdb_ctx);
+
+	if (idlen >= sizeof(ctx->db_id)) {
+		memcpy(id, &ctx->db_id, sizeof(ctx->db_id));
+	}
+
+	return sizeof(ctx->db_id);
+}
+
+struct db_context *db_open_ctdb(TALLOC_CTX *mem_ctx,
+				struct messaging_context *msg_ctx,
+				const char *name,
+				int hash_size, int tdb_flags,
+				int open_flags, mode_t mode,
+				enum dbwrap_lock_order lock_order,
+				uint64_t dbwrap_flags)
+{
+	struct db_context *result;
+	struct db_ctdb_ctx *db_ctdb;
+	char *db_path;
+	struct loadparm_context *lp_ctx;
+	TDB_DATA data;
+	TDB_DATA outdata = {0};
+	bool persistent = (tdb_flags & TDB_CLEAR_IF_FIRST) == 0;
+	int32_t cstatus;
+	int ret;
+
+	if (!lp_clustering()) {
+		DEBUG(10, ("Clustering disabled -- no ctdb\n"));
+		return NULL;
+	}
+
+	if (!(result = talloc_zero(mem_ctx, struct db_context))) {
+		DEBUG(0, ("talloc failed\n"));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	if (!(db_ctdb = talloc(result, struct db_ctdb_ctx))) {
+		DEBUG(0, ("talloc failed\n"));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	result->name = talloc_strdup(result, name);
+	if (result->name == NULL) {
+		DEBUG(0, ("talloc failed\n"));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	db_ctdb->transaction = NULL;
+	db_ctdb->db = result;
+
+	ret = ctdbd_db_attach(messaging_ctdb_connection(), name,
+			      &db_ctdb->db_id, persistent);
+	if (ret != 0) {
+		DEBUG(0, ("ctdbd_db_attach failed for %s: %s\n", name,
+			  strerror(ret)));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	if (tdb_flags & TDB_SEQNUM) {
+		data.dptr = (uint8_t *)&db_ctdb->db_id;
+		data.dsize = sizeof(db_ctdb->db_id);
+
+		ret = ctdbd_control_local(messaging_ctdb_connection(),
+					  CTDB_CONTROL_ENABLE_SEQNUM,
+					  0, 0, data,
+					  NULL, NULL, &cstatus);
+		if ((ret != 0) || cstatus != 0) {
+			DBG_ERR("ctdb_control for enable seqnum "
+				"failed: %s\n", strerror(ret));
+			TALLOC_FREE(result);
+			return NULL;
+		}
+	}
+
+	db_path = ctdbd_dbpath(messaging_ctdb_connection(), db_ctdb,
+			       db_ctdb->db_id);
+	if (db_path == NULL) {
+		DBG_ERR("ctdbd_dbpath failed\n");
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	result->persistent = persistent;
+	result->lock_order = lock_order;
+
+	data.dptr = (uint8_t *)&db_ctdb->db_id;
+	data.dsize = sizeof(db_ctdb->db_id);
+
+	ret = ctdbd_control_local(messaging_ctdb_connection(),
+				  CTDB_CONTROL_DB_OPEN_FLAGS,
+				  0, 0, data, NULL, &outdata, &cstatus);
+	if (ret != 0) {
+		DBG_ERR(" ctdb control for db_open_flags "
+			 "failed: %s\n", strerror(ret));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	if (cstatus != 0 || outdata.dsize != sizeof(int)) {
+		DBG_ERR("ctdb_control for db_open_flags failed\n");
+		TALLOC_FREE(outdata.dptr);
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	tdb_flags = *(int *)outdata.dptr;
+	TALLOC_FREE(outdata.dptr);
+
+	if (!result->persistent) {
+		ret = ctdb_async_ctx_init(NULL, messaging_tevent_context(msg_ctx));
+		if (ret != 0) {
+			DBG_ERR("ctdb_async_ctx_init failed: %s\n", strerror(ret));
+			TALLOC_FREE(result);
+			return NULL;
+		}
+	}
+
+	if (!result->persistent &&
+	    (dbwrap_flags & DBWRAP_FLAG_OPTIMIZE_READONLY_ACCESS))
+	{
+		TDB_DATA indata;
+
+		indata = make_tdb_data((uint8_t *)&db_ctdb->db_id,
+				       sizeof(db_ctdb->db_id));
+
+		ret = ctdbd_control_local(
+			messaging_ctdb_connection(),
+			CTDB_CONTROL_SET_DB_READONLY, 0, 0,
+			indata, NULL, NULL, &cstatus);
+		if ((ret != 0) || (cstatus != 0)) {
+			DEBUG(1, ("CTDB_CONTROL_SET_DB_READONLY failed: "
+				  "%s, %"PRIi32"\n", strerror(ret), cstatus));
+			TALLOC_FREE(result);
+			return NULL;
+		}
+	}
+
+	lp_ctx = loadparm_init_s3(db_path, loadparm_s3_helpers());
+
+	if (hash_size == 0) {
+		hash_size = lpcfg_tdb_hash_size(lp_ctx, db_path);
+	}
+
+	db_ctdb->wtdb = tdb_wrap_open(db_ctdb, db_path, hash_size,
+				      lpcfg_tdb_flags(lp_ctx, tdb_flags),
+				      O_RDWR, 0);
+	talloc_unlink(db_path, lp_ctx);
+	if (db_ctdb->wtdb == NULL) {
+		DEBUG(0, ("Could not open tdb %s: %s\n", db_path, strerror(errno)));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+	talloc_free(db_path);
+
+	/* honor permissions if user has specified O_CREAT */
+	if (open_flags & O_CREAT) {
+		int fd;
+		fd = tdb_fd(db_ctdb->wtdb->tdb);
+		ret = fchmod(fd, mode);
+		if (ret == -1) {
+			DBG_WARNING("fchmod failed: %s\n",
+				    strerror(errno));
+			TALLOC_FREE(result);
+			return NULL;
+		}
+	}
+
+	if (result->persistent) {
+		db_ctdb->lock_ctx = g_lock_ctx_init(db_ctdb, msg_ctx);
+		if (db_ctdb->lock_ctx == NULL) {
+			DEBUG(0, ("g_lock_ctx_init failed\n"));
+			TALLOC_FREE(result);
+			return NULL;
+		}
+	}
+
+	db_ctdb->warn_unlock_msecs = lp_parm_int(-1, "ctdb",
+						 "unlock_warn_threshold", 5);
+	db_ctdb->warn_migrate_attempts = lp_parm_int(-1, "ctdb",
+						     "migrate_attempts", 10);
+	db_ctdb->warn_migrate_msecs = lp_parm_int(-1, "ctdb",
+						  "migrate_duration", 5000);
+	db_ctdb->warn_locktime_msecs = lp_ctdb_locktime_warn_threshold();
+
+	result->private_data = (void *)db_ctdb;
+	result->fetch_locked = db_ctdb_fetch_locked;
+	result->parse_record = db_ctdb_parse_record;
+	result->parse_record_send = db_ctdb_parse_record_send;
+	result->parse_record_recv = db_ctdb_parse_record_recv;
+	result->traverse = db_ctdb_traverse;
+	result->traverse_read = db_ctdb_traverse_read;
+	result->get_seqnum = db_ctdb_get_seqnum;
+	result->transaction_start = db_ctdb_transaction_start;
+	result->transaction_commit = db_ctdb_transaction_commit;
+	result->transaction_cancel = db_ctdb_transaction_cancel;
+	result->id = db_ctdb_id;
+
+	DEBUG(3,("db_open_ctdb: opened database '%s' with dbid 0x%x\n",
+		 name, db_ctdb->db_id));
+
+	return result;
+}
diff --git a/source3/lib/dbwrap/dbwrap_ctdb.h b/source3/lib/dbwrap/dbwrap_ctdb.h
new file mode 100644
index 0000000..0b82479
--- /dev/null
+++ b/source3/lib/dbwrap/dbwrap_ctdb.h
@@ -0,0 +1,40 @@
+/* 
+   Unix SMB/CIFS implementation.
+   Database interface wrapper around ctdbd
+   Copyright (C) Volker Lendecke 2007-2009
+   Copyright (C) Michael Adam 2009
+
+   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/>.
+*/
+
+#ifndef __DBWRAP_CTDB_H__
+#define __DBWRAP_CTDB_H__
+
+#include <talloc.h>
+
+#include "dbwrap/dbwrap_private.h"
+
+struct db_context;
+struct ctdbd_connection;
+
+struct db_context *db_open_ctdb(TALLOC_CTX *mem_ctx,
+				struct messaging_context *msg_ctx,
+				const char *name,
+				int hash_size, int tdb_flags,
+				int open_flags, mode_t mode,
+				enum dbwrap_lock_order lock_order,
+				uint64_t dbwrap_flags);
+int ctdb_async_ctx_reinit(TALLOC_CTX *mem_ctx, struct tevent_context *ev);
+
+#endif /* __DBWRAP_CTDB_H__ */
diff --git a/source3/lib/dbwrap/dbwrap_open.c b/source3/lib/dbwrap/dbwrap_open.c
new file mode 100644
index 0000000..52c8a94
--- /dev/null
+++ b/source3/lib/dbwrap/dbwrap_open.c
@@ -0,0 +1,197 @@
+/*
+   Unix SMB/CIFS implementation.
+   Database interface wrapper
+
+   Copyright (C) Volker Lendecke 2005-2007
+
+   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 "includes.h"
+#include "dbwrap/dbwrap.h"
+#include "dbwrap/dbwrap_private.h"
+#include "dbwrap/dbwrap_open.h"
+#include "dbwrap/dbwrap_tdb.h"
+#include "dbwrap/dbwrap_ctdb.h"
+#include "lib/param/param.h"
+#include "lib/cluster_support.h"
+#include "lib/messages_ctdb.h"
+#include "util_tdb.h"
+#include "ctdbd_conn.h"
+#include "global_contexts.h"
+
+bool db_is_local(const char *name)
+{
+	const char *sockname = lp_ctdbd_socket();
+
+	if (lp_clustering() && socket_exist(sockname)) {
+		const char *partname;
+		/* ctdb only wants the file part of the name */
+		partname = strrchr(name, '/');
+		if (partname) {
+			partname++;
+		} else {
+			partname = name;
+		}
+		/* allow ctdb for individual databases to be disabled */
+		if (lp_parm_bool(-1, "ctdb", partname, True)) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
+/**
+ * open a database
+ */
+struct db_context *db_open(TALLOC_CTX *mem_ctx,
+			   const char *name,
+			   int hash_size, int tdb_flags,
+			   int open_flags, mode_t mode,
+			   enum dbwrap_lock_order lock_order,
+			   uint64_t dbwrap_flags)
+{
+	struct db_context *result = NULL;
+	const char *base;
+	struct loadparm_context *lp_ctx = NULL;
+
+	if ((lock_order != DBWRAP_LOCK_ORDER_NONE) &&
+	    !DBWRAP_LOCK_ORDER_VALID(lock_order)) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	base = strrchr_m(name, '/');
+	if (base != NULL) {
+		base++;
+	} else {
+		base = name;
+	}
+
+	if (tdb_flags & TDB_CLEAR_IF_FIRST) {
+		bool try_readonly = false;
+
+		if (dbwrap_flags & DBWRAP_FLAG_OPTIMIZE_READONLY_ACCESS) {
+			try_readonly = true;
+		}
+
+		try_readonly = lp_parm_bool(-1, "dbwrap_optimize_readonly", "*", try_readonly);
+		try_readonly = lp_parm_bool(-1, "dbwrap_optimize_readonly", base, try_readonly);
+
+		if (try_readonly) {
+			dbwrap_flags |= DBWRAP_FLAG_OPTIMIZE_READONLY_ACCESS;
+		} else {
+			dbwrap_flags &= ~DBWRAP_FLAG_OPTIMIZE_READONLY_ACCESS;
+		}
+	}
+
+	if (tdb_flags & TDB_CLEAR_IF_FIRST) {
+		bool try_mutex = true;
+		bool require_mutex = false;
+
+		try_mutex = lp_parm_bool(-1, "dbwrap_tdb_mutexes", "*", try_mutex);
+		try_mutex = lp_parm_bool(-1, "dbwrap_tdb_mutexes", base, try_mutex);
+
+		if (!lp_use_mmap()) {
+			/*
+			 * Mutexes require mmap. "use mmap = no" can
+			 * be a debugging tool, so let it override the
+			 * mutex parameters
+			 */
+			try_mutex = false;
+		}
+
+		if (try_mutex && tdb_runtime_check_for_robust_mutexes()) {
+			tdb_flags |= TDB_MUTEX_LOCKING;
+		}
+
+		require_mutex = lp_parm_bool(-1, "dbwrap_tdb_require_mutexes",
+					   "*", require_mutex);
+		require_mutex = lp_parm_bool(-1, "dbwrap_tdb_require_mutexes",
+					   base, require_mutex);
+
+		if (require_mutex) {
+			tdb_flags |= TDB_MUTEX_LOCKING;
+		}
+	}
+
+	if (lp_clustering()) {
+		const char *sockname;
+
+		sockname = lp_ctdbd_socket();
+		if (!socket_exist(sockname)) {
+			DBG_WARNING("ctdb socket does %s not exist - "
+				    "is ctdb not running?\n",
+				    sockname);
+			return NULL;
+		}
+
+		/* allow ctdb for individual databases to be disabled */
+		if (lp_parm_bool(-1, "ctdb", base, true)) {
+			struct messaging_context *msg_ctx;
+			struct ctdbd_connection *conn;
+
+			/*
+			 * Initialize messaging before getting the ctdb
+			 * connection, as the ctdb connection requires messaging
+			 * to be initialized.
+			 */
+			msg_ctx = global_messaging_context();
+			if (msg_ctx == NULL) {
+				DBG_ERR("Failed to initialize messaging\n");
+				return NULL;
+			}
+
+			conn = messaging_ctdb_connection();
+			if (conn == NULL) {
+				DBG_WARNING("No ctdb connection\n");
+				errno = EIO;
+				return NULL;
+			}
+
+			result = db_open_ctdb(mem_ctx, msg_ctx, base,
+					      hash_size,
+					      tdb_flags, open_flags, mode,
+					      lock_order, dbwrap_flags);
+			if (result == NULL) {
+				DBG_ERR("failed to attach to ctdb %s\n", base);
+				if (errno == 0) {
+					errno = EIO;
+				}
+				return NULL;
+			}
+
+			return result;
+		}
+	}
+
+	lp_ctx = loadparm_init_s3(mem_ctx, loadparm_s3_helpers());
+
+	if (hash_size == 0) {
+		hash_size = lpcfg_tdb_hash_size(lp_ctx, name);
+	}
+	tdb_flags = lpcfg_tdb_flags(lp_ctx, tdb_flags);
+
+	result = dbwrap_local_open(mem_ctx,
+				   name,
+				   hash_size,
+				   tdb_flags,
+				   open_flags,
+				   mode,
+				   lock_order,
+				   dbwrap_flags);
+	talloc_unlink(mem_ctx, lp_ctx);
+	return result;
+}
diff --git a/source3/lib/dbwrap/dbwrap_open.h b/source3/lib/dbwrap/dbwrap_open.h
new file mode 100644
index 0000000..d14794e
--- /dev/null
+++ b/source3/lib/dbwrap/dbwrap_open.h
@@ -0,0 +1,45 @@
+/* 
+   Unix SMB/CIFS implementation.
+   Database interface wrapper around tdb
+
+   Copyright (C) Volker Lendecke 2005-2007
+
+   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/>.
+*/
+
+#ifndef __DBWRAP_OPEN_H__
+#define __DBWRAP_OPEN_H__
+
+struct db_context;
+
+/**
+ * Convenience function to check whether a tdb database
+ * is local or clustered (ctdb) in a clustered environment.
+ */
+bool db_is_local(const char *name);
+
+/**
+ * Convenience function that will determine whether to
+ * open a tdb database via the tdb backend or via the ctdb
+ * backend, based on lp_clustering() and a db-specific
+ * settings.
+ */
+struct db_context *db_open(TALLOC_CTX *mem_ctx,
+			   const char *name,
+			   int hash_size, int tdb_flags,
+			   int open_flags, mode_t mode,
+			   enum dbwrap_lock_order lock_order,
+			   uint64_t dbwrap_flags);
+
+#endif /* __DBWRAP_OPEN_H__ */
diff --git a/source3/lib/dbwrap/dbwrap_watch.c b/source3/lib/dbwrap/dbwrap_watch.c
new file mode 100644
index 0000000..df93119
--- /dev/null
+++ b/source3/lib/dbwrap/dbwrap_watch.c
@@ -0,0 +1,1285 @@
+/*
+   Unix SMB/CIFS implementation.
+   Watch dbwrap record changes
+   Copyright (C) Volker Lendecke 2012
+
+   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 "includes.h"
+#include "system/filesys.h"
+#include "lib/util/server_id.h"
+#include "dbwrap/dbwrap.h"
+#include "dbwrap_watch.h"
+#include "dbwrap_open.h"
+#include "lib/util/util_tdb.h"
+#include "lib/util/tevent_ntstatus.h"
+#include "serverid.h"
+#include "server_id_watch.h"
+#include "lib/dbwrap/dbwrap_private.h"
+
+struct dbwrap_watcher {
+	/*
+	 * Process watching this record
+	 */
+	struct server_id pid;
+	/*
+	 * Individual instance inside the waiter, incremented each
+	 * time a watcher is created
+	 */
+	uint64_t instance;
+};
+
+#define DBWRAP_WATCHER_BUF_LENGTH (SERVER_ID_BUF_LENGTH + sizeof(uint64_t))
+#define DBWRAP_MAX_WATCHERS (INT32_MAX/DBWRAP_WATCHER_BUF_LENGTH)
+
+/*
+ * Watched records contain a header of:
+ *
+ * [uint32] num_records
+ * 0 [DBWRAP_WATCHER_BUF_LENGTH]              \
+ * 1 [DBWRAP_WATCHER_BUF_LENGTH]              |
+ * ..                                         |- Array of watchers
+ * (num_records-1)[DBWRAP_WATCHER_BUF_LENGTH] /
+ *
+ * [Remainder of record....]
+ *
+ * If this header is absent then this is a
+ * fresh record of length zero (no watchers).
+ */
+
+static bool dbwrap_watch_rec_parse(
+	TDB_DATA data,
+	uint8_t **pwatchers,
+	size_t *pnum_watchers,
+	TDB_DATA *pdata)
+{
+	size_t num_watchers;
+
+	if (data.dsize == 0) {
+		/* Fresh record */
+		if (pwatchers != NULL) {
+			*pwatchers = NULL;
+		}
+		if (pnum_watchers != NULL) {
+			*pnum_watchers = 0;
+		}
+		if (pdata != NULL) {
+			*pdata = (TDB_DATA) { .dptr = NULL };
+		}
+		return true;
+	}
+
+	if (data.dsize < sizeof(uint32_t)) {
+		/* Invalid record */
+		return false;
+	}
+
+	num_watchers = IVAL(data.dptr, 0);
+
+	data.dptr += sizeof(uint32_t);
+	data.dsize -= sizeof(uint32_t);
+
+	if (num_watchers > data.dsize/DBWRAP_WATCHER_BUF_LENGTH) {
+		/* Invalid record */
+		return false;
+	}
+
+	if (pwatchers != NULL) {
+		*pwatchers = data.dptr;
+	}
+	if (pnum_watchers != NULL) {
+		*pnum_watchers = num_watchers;
+	}
+	if (pdata != NULL) {
+		size_t watchers_len = num_watchers * DBWRAP_WATCHER_BUF_LENGTH;
+		*pdata = (TDB_DATA) {
+			.dptr = data.dptr + watchers_len,
+			.dsize = data.dsize - watchers_len
+		};
+	}
+
+	return true;
+}
+
+static void dbwrap_watcher_get(struct dbwrap_watcher *w,
+			       const uint8_t buf[DBWRAP_WATCHER_BUF_LENGTH])
+{
+	server_id_get(&w->pid, buf);
+	w->instance = BVAL(buf, SERVER_ID_BUF_LENGTH);
+}
+
+static void dbwrap_watcher_put(uint8_t buf[DBWRAP_WATCHER_BUF_LENGTH],
+			       const struct dbwrap_watcher *w)
+{
+	server_id_put(buf, w->pid);
+	SBVAL(buf, SERVER_ID_BUF_LENGTH, w->instance);
+}
+
+static void dbwrap_watch_log_invalid_record(
+	struct db_context *db, TDB_DATA key, TDB_DATA value)
+{
+	DBG_ERR("Found invalid record in %s\n", dbwrap_name(db));
+	dump_data(1, key.dptr, key.dsize);
+	dump_data(1, value.dptr, value.dsize);
+}
+
+struct db_watched_ctx {
+	struct db_context *backend;
+	struct messaging_context *msg;
+};
+
+struct db_watched_record {
+	struct db_record *rec;
+	struct server_id self;
+	struct {
+		struct db_record *rec;
+		TDB_DATA initial_value;
+		bool initial_valid;
+	} backend;
+	bool force_fini_store;
+	struct dbwrap_watcher added;
+	bool removed_first;
+	struct {
+		/*
+		 * The is the number of watcher records
+		 * parsed from backend.initial_value
+		 */
+		size_t count;
+		/*
+		 * This is the pointer to
+		 * the optentially first watcher record
+		 * parsed from backend.initial_value
+		 *
+		 * The pointer actually points to memory
+		 * in backend.initial_value.
+		 *
+		 * Note it might be NULL, if count is 0.
+		 */
+		uint8_t *first;
+		/*
+		 * This remembers if we already
+		 * notified the watchers.
+		 *
+		 * As we only need to do that once during:
+		 *   do_locked
+		 * or:
+		 *   between rec = fetch_locked
+		 *   and
+		 *   TALLOC_FREE(rec)
+		 */
+		bool alerted;
+	} watchers;
+	struct {
+		struct dbwrap_watcher watcher;
+	} wakeup;
+};
+
+static struct db_watched_record *db_record_get_watched_record(struct db_record *rec)
+{
+	/*
+	 * we can't use wrec = talloc_get_type_abort() here!
+	 * because wrec is likely a stack variable in
+	 * dbwrap_watched_do_locked_fn()
+	 *
+	 * In order to have a least some protection
+	 * we verify the cross reference pointers
+	 * between rec and wrec
+	 */
+	struct db_watched_record *wrec =
+		(struct db_watched_record *)rec->private_data;
+	SMB_ASSERT(wrec->rec == rec);
+	return wrec;
+}
+
+static NTSTATUS dbwrap_watched_record_storev(
+	struct db_watched_record *wrec,
+	const TDB_DATA *dbufs, int num_dbufs, int flags);
+static NTSTATUS dbwrap_watched_storev(struct db_record *rec,
+				      const TDB_DATA *dbufs, int num_dbufs,
+				      int flags);
+static NTSTATUS dbwrap_watched_delete(struct db_record *rec);
+static void dbwrap_watched_trigger_wakeup(struct messaging_context *msg_ctx,
+					  struct dbwrap_watcher *watcher);
+static int db_watched_record_destructor(struct db_watched_record *wrec);
+
+static void db_watched_record_init(struct db_context *db,
+				   struct messaging_context *msg_ctx,
+				   struct db_record *rec,
+				   struct db_watched_record *wrec,
+				   struct db_record *backend_rec,
+				   TDB_DATA backend_value)
+{
+	bool ok;
+
+	*rec = (struct db_record) {
+		.db = db,
+		.key = dbwrap_record_get_key(backend_rec),
+		.storev = dbwrap_watched_storev,
+		.delete_rec = dbwrap_watched_delete,
+		.private_data = wrec,
+	};
+
+	*wrec = (struct db_watched_record) {
+		.rec = rec,
+		.self = messaging_server_id(msg_ctx),
+		.backend = {
+			.rec = backend_rec,
+			.initial_value = backend_value,
+			.initial_valid = true,
+		},
+	};
+
+	ok = dbwrap_watch_rec_parse(backend_value,
+				    &wrec->watchers.first,
+				    &wrec->watchers.count,
+				    &rec->value);
+	if (!ok) {
+		dbwrap_watch_log_invalid_record(rec->db, rec->key, backend_value);
+		/* wipe invalid data */
+		rec->value = (TDB_DATA) { .dptr = NULL, .dsize = 0 };
+	}
+}
+
+static struct db_record *dbwrap_watched_fetch_locked(
+	struct db_context *db, TALLOC_CTX *mem_ctx, TDB_DATA key)
+{
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+	struct db_record *rec = NULL;
+	struct db_watched_record *wrec = NULL;
+	struct db_record *backend_rec = NULL;
+	TDB_DATA backend_value = { .dptr = NULL, };
+
+	rec = talloc_zero(mem_ctx, struct db_record);
+	if (rec == NULL) {
+		return NULL;
+	}
+	wrec = talloc_zero(rec, struct db_watched_record);
+	if (wrec == NULL) {
+		TALLOC_FREE(rec);
+		return NULL;
+	}
+
+	backend_rec = dbwrap_fetch_locked(ctx->backend, wrec, key);
+	if (backend_rec == NULL) {
+		TALLOC_FREE(rec);
+		return NULL;
+	}
+	backend_value = dbwrap_record_get_value(backend_rec);
+
+	db_watched_record_init(db, ctx->msg,
+			       rec, wrec,
+			       backend_rec, backend_value);
+	rec->value_valid = true;
+	talloc_set_destructor(wrec, db_watched_record_destructor);
+
+	return rec;
+}
+
+struct db_watched_record_fini_state {
+	struct db_watched_record *wrec;
+	TALLOC_CTX *frame;
+	TDB_DATA dbufs[2];
+	int num_dbufs;
+	bool ok;
+};
+
+static void db_watched_record_fini_fetcher(TDB_DATA key,
+					   TDB_DATA backend_value,
+					   void *private_data)
+{
+	struct db_watched_record_fini_state *state =
+		(struct db_watched_record_fini_state *)private_data;
+	struct db_watched_record *wrec = state->wrec;
+	struct db_record *rec = wrec->rec;
+	TDB_DATA value = {};
+	bool ok;
+	size_t copy_size;
+
+	/*
+	 * We're within dbwrap_parse_record()
+	 * and backend_value directly points into
+	 * the mmap'ed tdb, so we need to copy the
+	 * parts we require.
+	 */
+
+	ok = dbwrap_watch_rec_parse(backend_value, NULL, NULL, &value);
+	if (!ok) {
+		struct db_context *db = dbwrap_record_get_db(rec);
+
+		dbwrap_watch_log_invalid_record(db, key, backend_value);
+
+		/* wipe invalid data */
+		value = (TDB_DATA) { .dptr = NULL, .dsize = 0 };
+	}
+
+	copy_size = MIN(rec->value.dsize, value.dsize);
+	if (copy_size != 0) {
+		/*
+		 * First reuse the buffer we already had
+		 * as much as we can.
+		 */
+		memcpy(rec->value.dptr, value.dptr, copy_size);
+		state->dbufs[state->num_dbufs++] = rec->value;
+		value.dsize -= copy_size;
+		value.dptr += copy_size;
+	}
+
+	if (value.dsize != 0) {
+		uint8_t *p = NULL;
+
+		/*
+		 * There's still new data left
+		 * allocate it on callers stackframe
+		 */
+		p = talloc_memdup(state->frame, value.dptr, value.dsize);
+		if (p == NULL) {
+			DBG_WARNING("failed to allocate %zu bytes\n",
+				    value.dsize);
+			return;
+		}
+
+		state->dbufs[state->num_dbufs++] = (TDB_DATA) {
+			.dptr = p, .dsize = value.dsize,
+		};
+	}
+
+	state->ok = true;
+}
+
+static void db_watched_record_fini(struct db_watched_record *wrec)
+{
+	struct db_watched_record_fini_state state = { .wrec = wrec, };
+	struct db_context *backend = dbwrap_record_get_db(wrec->backend.rec);
+	struct db_record *rec = wrec->rec;
+	TDB_DATA key = dbwrap_record_get_key(wrec->backend.rec);
+	NTSTATUS status;
+
+	if (!wrec->force_fini_store) {
+		return;
+	}
+
+	if (wrec->backend.initial_valid) {
+		if (rec->value.dsize != 0) {
+			state.dbufs[state.num_dbufs++] = rec->value;
+		}
+	} else {
+		/*
+		 * We need to fetch the current
+		 * value from the backend again,
+		 * which may need to allocate memory
+		 * on the provided stackframe.
+		 */
+
+		state.frame = talloc_stackframe();
+
+		status = dbwrap_parse_record(backend, key,
+				db_watched_record_fini_fetcher, &state);
+		if (!NT_STATUS_IS_OK(status)) {
+			DBG_WARNING("dbwrap_parse_record failed: %s\n",
+				    nt_errstr(status));
+			TALLOC_FREE(state.frame);
+			return;
+		}
+		if (!state.ok) {
+			TALLOC_FREE(state.frame);
+			return;
+		}
+	}
+
+	/*
+	 * We don't want to wake up others just because
+	 * we added ourself as new watcher. But if we
+	 * removed outself from the first position
+	 * we need to alert the next one.
+	 */
+	if (!wrec->removed_first) {
+		dbwrap_watched_watch_skip_alerting(rec);
+	}
+
+	status = dbwrap_watched_record_storev(wrec, state.dbufs, state.num_dbufs, 0);
+	TALLOC_FREE(state.frame);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_WARNING("dbwrap_watched_record_storev failed: %s\n",
+			    nt_errstr(status));
+		return;
+	}
+
+	return;
+}
+
+static int db_watched_record_destructor(struct db_watched_record *wrec)
+{
+	struct db_record *rec = wrec->rec;
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		rec->db->private_data, struct db_watched_ctx);
+
+	db_watched_record_fini(wrec);
+	TALLOC_FREE(wrec->backend.rec);
+	dbwrap_watched_trigger_wakeup(ctx->msg, &wrec->wakeup.watcher);
+	return 0;
+}
+
+struct dbwrap_watched_do_locked_state {
+	struct db_context *db;
+	struct messaging_context *msg_ctx;
+	struct db_watched_record *wrec;
+	struct db_record *rec;
+	void (*fn)(struct db_record *rec,
+		   TDB_DATA value,
+		   void *private_data);
+	void *private_data;
+};
+
+static void dbwrap_watched_do_locked_fn(
+	struct db_record *backend_rec,
+	TDB_DATA backend_value,
+	void *private_data)
+{
+	struct dbwrap_watched_do_locked_state *state =
+		(struct dbwrap_watched_do_locked_state *)private_data;
+
+	db_watched_record_init(state->db, state->msg_ctx,
+			       state->rec, state->wrec,
+			       backend_rec, backend_value);
+
+	state->fn(state->rec, state->rec->value, state->private_data);
+
+	db_watched_record_fini(state->wrec);
+}
+
+static NTSTATUS dbwrap_watched_do_locked(struct db_context *db, TDB_DATA key,
+					 void (*fn)(struct db_record *rec,
+						    TDB_DATA value,
+						    void *private_data),
+					 void *private_data)
+{
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+	struct db_watched_record wrec;
+	struct db_record rec;
+	struct dbwrap_watched_do_locked_state state = {
+		.db = db, .msg_ctx = ctx->msg,
+		.rec = &rec, .wrec = &wrec,
+		.fn = fn, .private_data = private_data,
+	};
+	NTSTATUS status;
+
+	status = dbwrap_do_locked(
+		ctx->backend, key, dbwrap_watched_do_locked_fn, &state);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("dbwrap_do_locked returned %s\n", nt_errstr(status));
+		return status;
+	}
+
+	DBG_DEBUG("dbwrap_watched_do_locked_fn returned\n");
+
+	dbwrap_watched_trigger_wakeup(state.msg_ctx, &wrec.wakeup.watcher);
+
+	return NT_STATUS_OK;
+}
+
+static void dbwrap_watched_record_prepare_wakeup(
+	struct db_watched_record *wrec)
+{
+	/*
+	 * Wakeup only needs to happen once (if at all)
+	 */
+	if (wrec->watchers.alerted) {
+		/* already done */
+		return;
+	}
+	wrec->watchers.alerted = true;
+
+	if (wrec->watchers.count == 0) {
+		DBG_DEBUG("No watchers\n");
+		return;
+	}
+
+	while (wrec->watchers.count != 0) {
+		struct server_id_buf tmp;
+		bool exists;
+
+		dbwrap_watcher_get(&wrec->wakeup.watcher, wrec->watchers.first);
+		exists = serverid_exists(&wrec->wakeup.watcher.pid);
+		if (!exists) {
+			DBG_DEBUG("Discard non-existing waiter %s:%"PRIu64"\n",
+				  server_id_str_buf(wrec->wakeup.watcher.pid, &tmp),
+				  wrec->wakeup.watcher.instance);
+			wrec->watchers.first += DBWRAP_WATCHER_BUF_LENGTH;
+			wrec->watchers.count -= 1;
+			continue;
+		}
+
+		/*
+		 * We will only wakeup the first waiter, via
+		 * dbwrap_watched_trigger_wakeup(), but keep
+		 * all (including the first one) in the list that
+		 * will be flushed back to the backend record
+		 * again. Waiters are removing their entries
+		 * via dbwrap_watched_watch_remove_instance()
+		 * when they no longer want to monitor the record.
+		 */
+		DBG_DEBUG("Will alert first waiter %s:%"PRIu64"\n",
+			  server_id_str_buf(wrec->wakeup.watcher.pid, &tmp),
+			  wrec->wakeup.watcher.instance);
+		break;
+	}
+}
+
+static void dbwrap_watched_trigger_wakeup(struct messaging_context *msg_ctx,
+					  struct dbwrap_watcher *watcher)
+{
+	struct server_id_buf tmp;
+	uint8_t instance_buf[8];
+	NTSTATUS status;
+
+	if (watcher->instance == 0) {
+		DBG_DEBUG("No one to wakeup\n");
+		return;
+	}
+
+	DBG_DEBUG("Alerting %s:%"PRIu64"\n",
+		  server_id_str_buf(watcher->pid, &tmp),
+		  watcher->instance);
+
+	SBVAL(instance_buf, 0, watcher->instance);
+
+	status = messaging_send_buf(
+		msg_ctx,
+		watcher->pid,
+		MSG_DBWRAP_MODIFIED,
+		instance_buf,
+		sizeof(instance_buf));
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_WARNING("messaging_send_buf to %s failed: %s - ignoring...\n",
+			    server_id_str_buf(watcher->pid, &tmp),
+			    nt_errstr(status));
+	}
+}
+
+static NTSTATUS dbwrap_watched_record_storev(
+	struct db_watched_record *wrec,
+	const TDB_DATA *dbufs, int num_dbufs, int flags)
+{
+	uint8_t num_watchers_buf[4] = { 0 };
+	uint8_t add_buf[DBWRAP_WATCHER_BUF_LENGTH];
+	size_t num_store_watchers;
+	TDB_DATA my_dbufs[num_dbufs+3];
+	int num_my_dbufs = 0;
+	NTSTATUS status;
+	size_t add_count = 0;
+
+	dbwrap_watched_record_prepare_wakeup(wrec);
+
+	wrec->backend.initial_valid = false;
+	wrec->force_fini_store = false;
+
+	if (wrec->added.pid.pid != 0) {
+		dbwrap_watcher_put(add_buf, &wrec->added);
+		add_count = 1;
+	}
+
+	num_store_watchers = wrec->watchers.count + add_count;
+	if (num_store_watchers == 0 && num_dbufs == 0) {
+		status = dbwrap_record_delete(wrec->backend.rec);
+		return status;
+	}
+	if (num_store_watchers >= DBWRAP_MAX_WATCHERS) {
+		DBG_WARNING("Can't handle %zu watchers\n",
+			    num_store_watchers);
+		return NT_STATUS_INSUFFICIENT_RESOURCES;
+	}
+
+	SIVAL(num_watchers_buf, 0, num_store_watchers);
+
+	my_dbufs[num_my_dbufs++] = (TDB_DATA) {
+		.dptr = num_watchers_buf, .dsize = sizeof(num_watchers_buf),
+	};
+	if (wrec->watchers.count != 0) {
+		my_dbufs[num_my_dbufs++] = (TDB_DATA) {
+			.dptr = wrec->watchers.first, .dsize = wrec->watchers.count * DBWRAP_WATCHER_BUF_LENGTH,
+		};
+	}
+	if (add_count != 0) {
+		my_dbufs[num_my_dbufs++] = (TDB_DATA) {
+			.dptr = add_buf,
+			.dsize = sizeof(add_buf),
+		};
+	}
+	if (num_dbufs != 0) {
+		memcpy(my_dbufs+num_my_dbufs, dbufs, num_dbufs * sizeof(*dbufs));
+		num_my_dbufs += num_dbufs;
+	}
+
+	SMB_ASSERT(num_my_dbufs <= ARRAY_SIZE(my_dbufs));
+
+	status = dbwrap_record_storev(
+		wrec->backend.rec, my_dbufs, num_my_dbufs, flags);
+	return status;
+}
+
+static NTSTATUS dbwrap_watched_storev(struct db_record *rec,
+				      const TDB_DATA *dbufs, int num_dbufs,
+				      int flags)
+{
+	struct db_watched_record *wrec = db_record_get_watched_record(rec);
+
+	return dbwrap_watched_record_storev(wrec, dbufs, num_dbufs, flags);
+}
+
+static NTSTATUS dbwrap_watched_delete(struct db_record *rec)
+{
+	struct db_watched_record *wrec = db_record_get_watched_record(rec);
+
+	/*
+	 * dbwrap_watched_record_storev() will figure out
+	 * if the record should be deleted or if there are still
+	 * watchers to be stored.
+	 */
+	return dbwrap_watched_record_storev(wrec, NULL, 0, 0);
+}
+
+struct dbwrap_watched_traverse_state {
+	int (*fn)(struct db_record *rec, void *private_data);
+	void *private_data;
+};
+
+static int dbwrap_watched_traverse_fn(struct db_record *rec,
+				      void *private_data)
+{
+	struct dbwrap_watched_traverse_state *state = private_data;
+	struct db_record prec = *rec;
+	bool ok;
+
+	ok = dbwrap_watch_rec_parse(rec->value, NULL, NULL, &prec.value);
+	if (!ok) {
+		return 0;
+	}
+	if (prec.value.dsize == 0) {
+		return 0;
+	}
+	prec.value_valid = true;
+
+	return state->fn(&prec, state->private_data);
+}
+
+static int dbwrap_watched_traverse(struct db_context *db,
+				   int (*fn)(struct db_record *rec,
+					     void *private_data),
+				   void *private_data)
+{
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+	struct dbwrap_watched_traverse_state state = {
+		.fn = fn, .private_data = private_data };
+	NTSTATUS status;
+	int ret;
+
+	status = dbwrap_traverse(
+		ctx->backend, dbwrap_watched_traverse_fn, &state, &ret);
+	if (!NT_STATUS_IS_OK(status)) {
+		return -1;
+	}
+	return ret;
+}
+
+static int dbwrap_watched_traverse_read(struct db_context *db,
+					int (*fn)(struct db_record *rec,
+						  void *private_data),
+					void *private_data)
+{
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+	struct dbwrap_watched_traverse_state state = {
+		.fn = fn, .private_data = private_data };
+	NTSTATUS status;
+	int ret;
+
+	status = dbwrap_traverse_read(
+		ctx->backend, dbwrap_watched_traverse_fn, &state, &ret);
+	if (!NT_STATUS_IS_OK(status)) {
+		return -1;
+	}
+	return ret;
+}
+
+static int dbwrap_watched_get_seqnum(struct db_context *db)
+{
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+	return dbwrap_get_seqnum(ctx->backend);
+}
+
+static int dbwrap_watched_transaction_start(struct db_context *db)
+{
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+	return dbwrap_transaction_start(ctx->backend);
+}
+
+static int dbwrap_watched_transaction_commit(struct db_context *db)
+{
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+	return dbwrap_transaction_commit(ctx->backend);
+}
+
+static int dbwrap_watched_transaction_cancel(struct db_context *db)
+{
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+	return dbwrap_transaction_cancel(ctx->backend);
+}
+
+struct dbwrap_watched_parse_record_state {
+	struct db_context *db;
+	void (*parser)(TDB_DATA key, TDB_DATA data, void *private_data);
+	void *private_data;
+	bool ok;
+};
+
+static void dbwrap_watched_parse_record_parser(TDB_DATA key, TDB_DATA data,
+					       void *private_data)
+{
+	struct dbwrap_watched_parse_record_state *state = private_data;
+	TDB_DATA userdata;
+
+	state->ok = dbwrap_watch_rec_parse(data, NULL, NULL, &userdata);
+	if (!state->ok) {
+		dbwrap_watch_log_invalid_record(state->db, key, data);
+		return;
+	}
+
+	state->parser(key, userdata, state->private_data);
+}
+
+static NTSTATUS dbwrap_watched_parse_record(
+	struct db_context *db, TDB_DATA key,
+	void (*parser)(TDB_DATA key, TDB_DATA data, void *private_data),
+	void *private_data)
+{
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+	struct dbwrap_watched_parse_record_state state = {
+		.db = db,
+		.parser = parser,
+		.private_data = private_data,
+	};
+	NTSTATUS status;
+
+	status = dbwrap_parse_record(
+		ctx->backend, key, dbwrap_watched_parse_record_parser, &state);
+	if (!NT_STATUS_IS_OK(status)) {
+		return status;
+	}
+	if (!state.ok) {
+		return NT_STATUS_NOT_FOUND;
+	}
+	return NT_STATUS_OK;
+}
+
+static void dbwrap_watched_parse_record_done(struct tevent_req *subreq);
+
+static struct tevent_req *dbwrap_watched_parse_record_send(
+	TALLOC_CTX *mem_ctx,
+	struct tevent_context *ev,
+	struct db_context *db,
+	TDB_DATA key,
+	void (*parser)(TDB_DATA key, TDB_DATA data, void *private_data),
+	void *private_data,
+	enum dbwrap_req_state *req_state)
+{
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+	struct tevent_req *req = NULL;
+	struct tevent_req *subreq = NULL;
+	struct dbwrap_watched_parse_record_state *state = NULL;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct dbwrap_watched_parse_record_state);
+	if (req == NULL) {
+		*req_state = DBWRAP_REQ_ERROR;
+		return NULL;
+	}
+
+	*state = (struct dbwrap_watched_parse_record_state) {
+		.parser = parser,
+		.private_data = private_data,
+		.ok = true,
+	};
+
+	subreq = dbwrap_parse_record_send(state,
+					  ev,
+					  ctx->backend,
+					  key,
+					  dbwrap_watched_parse_record_parser,
+					  state,
+					  req_state);
+	if (tevent_req_nomem(subreq, req)) {
+		*req_state = DBWRAP_REQ_ERROR;
+		return tevent_req_post(req, ev);
+	}
+
+	tevent_req_set_callback(subreq, dbwrap_watched_parse_record_done, req);
+	return req;
+}
+
+static void dbwrap_watched_parse_record_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(
+		subreq, struct tevent_req);
+	struct dbwrap_watched_parse_record_state *state = tevent_req_data(
+		req, struct dbwrap_watched_parse_record_state);
+	NTSTATUS status;
+
+	status = dbwrap_parse_record_recv(subreq);
+	TALLOC_FREE(subreq);
+	if (tevent_req_nterror(req, status)) {
+		return;
+	}
+
+	if (!state->ok) {
+		tevent_req_nterror(req, NT_STATUS_NOT_FOUND);
+		return;
+	}
+
+	tevent_req_done(req);
+	return;
+}
+
+static NTSTATUS dbwrap_watched_parse_record_recv(struct tevent_req *req)
+{
+	NTSTATUS status;
+
+	if (tevent_req_is_nterror(req, &status)) {
+		tevent_req_received(req);
+		return status;
+	}
+
+	tevent_req_received(req);
+	return NT_STATUS_OK;
+}
+
+static int dbwrap_watched_exists(struct db_context *db, TDB_DATA key)
+{
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+
+	return dbwrap_exists(ctx->backend, key);
+}
+
+static size_t dbwrap_watched_id(struct db_context *db, uint8_t *id,
+				size_t idlen)
+{
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+
+	return dbwrap_db_id(ctx->backend, id, idlen);
+}
+
+struct db_context *db_open_watched(TALLOC_CTX *mem_ctx,
+				   struct db_context **backend,
+				   struct messaging_context *msg)
+{
+	struct db_context *db;
+	struct db_watched_ctx *ctx;
+
+	db = talloc_zero(mem_ctx, struct db_context);
+	if (db == NULL) {
+		return NULL;
+	}
+	ctx = talloc_zero(db, struct db_watched_ctx);
+	if (ctx == NULL) {
+		TALLOC_FREE(db);
+		return NULL;
+	}
+	db->private_data = ctx;
+
+	ctx->msg = msg;
+
+	ctx->backend = talloc_move(ctx, backend);
+	db->lock_order = ctx->backend->lock_order;
+	ctx->backend->lock_order = DBWRAP_LOCK_ORDER_NONE;
+
+	db->fetch_locked = dbwrap_watched_fetch_locked;
+	db->do_locked = dbwrap_watched_do_locked;
+	db->traverse = dbwrap_watched_traverse;
+	db->traverse_read = dbwrap_watched_traverse_read;
+	db->get_seqnum = dbwrap_watched_get_seqnum;
+	db->transaction_start = dbwrap_watched_transaction_start;
+	db->transaction_commit = dbwrap_watched_transaction_commit;
+	db->transaction_cancel = dbwrap_watched_transaction_cancel;
+	db->parse_record = dbwrap_watched_parse_record;
+	db->parse_record_send = dbwrap_watched_parse_record_send;
+	db->parse_record_recv = dbwrap_watched_parse_record_recv;
+	db->exists = dbwrap_watched_exists;
+	db->id = dbwrap_watched_id;
+	db->name = dbwrap_name(ctx->backend);
+
+	return db;
+}
+
+uint64_t dbwrap_watched_watch_add_instance(struct db_record *rec)
+{
+	struct db_watched_record *wrec = db_record_get_watched_record(rec);
+	static uint64_t global_instance = 1;
+
+	SMB_ASSERT(wrec->added.instance == 0);
+
+	wrec->added = (struct dbwrap_watcher) {
+		.pid = wrec->self,
+		.instance = global_instance++,
+	};
+
+	wrec->force_fini_store = true;
+
+	return wrec->added.instance;
+}
+
+void dbwrap_watched_watch_remove_instance(struct db_record *rec, uint64_t instance)
+{
+	struct db_watched_record *wrec = db_record_get_watched_record(rec);
+	struct dbwrap_watcher clear_watcher = {
+		.pid = wrec->self,
+		.instance = instance,
+	};
+	size_t i;
+	struct server_id_buf buf;
+
+	if (instance == 0) {
+		return;
+	}
+
+	if (wrec->added.instance == instance) {
+		SMB_ASSERT(server_id_equal(&wrec->added.pid, &wrec->self));
+		DBG_DEBUG("Watcher %s:%"PRIu64" reverted from adding\n",
+			  server_id_str_buf(clear_watcher.pid, &buf),
+			  clear_watcher.instance);
+		ZERO_STRUCT(wrec->added);
+	}
+
+	for (i=0; i < wrec->watchers.count; i++) {
+		struct dbwrap_watcher watcher;
+		size_t off = i*DBWRAP_WATCHER_BUF_LENGTH;
+		size_t next_off;
+		size_t full_len;
+		size_t move_len;
+
+		dbwrap_watcher_get(&watcher, wrec->watchers.first + off);
+
+		if (clear_watcher.instance != watcher.instance) {
+			continue;
+		}
+		if (!server_id_equal(&clear_watcher.pid, &watcher.pid)) {
+			continue;
+		}
+
+		wrec->force_fini_store = true;
+
+		if (i == 0) {
+			DBG_DEBUG("Watcher %s:%"PRIu64" removed from first position of %zu\n",
+				  server_id_str_buf(clear_watcher.pid, &buf),
+				  clear_watcher.instance,
+				  wrec->watchers.count);
+			wrec->watchers.first += DBWRAP_WATCHER_BUF_LENGTH;
+			wrec->watchers.count -= 1;
+			wrec->removed_first = true;
+			return;
+		}
+		if (i == (wrec->watchers.count-1)) {
+			DBG_DEBUG("Watcher %s:%"PRIu64" removed from last position of %zu\n",
+				  server_id_str_buf(clear_watcher.pid, &buf),
+				  clear_watcher.instance,
+				  wrec->watchers.count);
+			wrec->watchers.count -= 1;
+			return;
+		}
+
+		DBG_DEBUG("Watcher %s:%"PRIu64" cleared at position %zu from %zu\n",
+			  server_id_str_buf(clear_watcher.pid, &buf),
+			  clear_watcher.instance, i+1,
+			  wrec->watchers.count);
+
+		next_off = off + DBWRAP_WATCHER_BUF_LENGTH;
+		full_len = wrec->watchers.count * DBWRAP_WATCHER_BUF_LENGTH;
+		move_len = full_len - next_off;
+		memmove(wrec->watchers.first + off,
+			wrec->watchers.first + next_off,
+			move_len);
+		wrec->watchers.count -= 1;
+		return;
+	}
+
+	DBG_DEBUG("Watcher %s:%"PRIu64" not found in %zu watchers\n",
+		  server_id_str_buf(clear_watcher.pid, &buf),
+		  clear_watcher.instance,
+		  wrec->watchers.count);
+	return;
+}
+
+void dbwrap_watched_watch_skip_alerting(struct db_record *rec)
+{
+	struct db_watched_record *wrec = db_record_get_watched_record(rec);
+
+	wrec->wakeup.watcher = (struct dbwrap_watcher) { .instance = 0, };
+	wrec->watchers.alerted = true;
+}
+
+void dbwrap_watched_watch_reset_alerting(struct db_record *rec)
+{
+	struct db_watched_record *wrec = db_record_get_watched_record(rec);
+
+	wrec->wakeup.watcher = (struct dbwrap_watcher) { .instance = 0, };
+	wrec->watchers.alerted = false;
+}
+
+void dbwrap_watched_watch_force_alerting(struct db_record *rec)
+{
+	struct db_watched_record *wrec = db_record_get_watched_record(rec);
+
+	dbwrap_watched_record_prepare_wakeup(wrec);
+}
+
+struct dbwrap_watched_watch_state {
+	struct db_context *db;
+	TDB_DATA key;
+	struct dbwrap_watcher watcher;
+	struct server_id blocker;
+	bool blockerdead;
+};
+
+static bool dbwrap_watched_msg_filter(struct messaging_rec *rec,
+				      void *private_data);
+static void dbwrap_watched_watch_done(struct tevent_req *subreq);
+static void dbwrap_watched_watch_blocker_died(struct tevent_req *subreq);
+static int dbwrap_watched_watch_state_destructor(
+	struct dbwrap_watched_watch_state *state);
+
+struct tevent_req *dbwrap_watched_watch_send(TALLOC_CTX *mem_ctx,
+					     struct tevent_context *ev,
+					     struct db_record *rec,
+					     uint64_t resumed_instance,
+					     struct server_id blocker)
+{
+	struct db_context *db = dbwrap_record_get_db(rec);
+	struct db_watched_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_watched_ctx);
+	struct db_watched_record *wrec = db_record_get_watched_record(rec);
+	struct tevent_req *req, *subreq;
+	struct dbwrap_watched_watch_state *state;
+	uint64_t instance;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct dbwrap_watched_watch_state);
+	if (req == NULL) {
+		return NULL;
+	}
+	state->db = db;
+	state->blocker = blocker;
+
+	if (ctx->msg == NULL) {
+		tevent_req_nterror(req, NT_STATUS_NOT_SUPPORTED);
+		return tevent_req_post(req, ev);
+	}
+
+	if (resumed_instance == 0 && wrec->added.instance == 0) {
+		/*
+		 * Adding a new instance
+		 */
+		instance = dbwrap_watched_watch_add_instance(rec);
+	} else if (resumed_instance != 0 && wrec->added.instance == 0) {
+		/*
+		 * Resuming an existing instance that was
+		 * already present before do_locked started
+		 */
+		instance = resumed_instance;
+	} else if (resumed_instance == wrec->added.instance) {
+		/*
+		 * The caller used dbwrap_watched_watch_add_instance()
+		 * already during this do_locked() invocation.
+		 */
+		instance = resumed_instance;
+	} else {
+		tevent_req_nterror(req, NT_STATUS_REQUEST_NOT_ACCEPTED);
+		return tevent_req_post(req, ev);
+	}
+
+	state->watcher = (struct dbwrap_watcher) {
+		.pid = messaging_server_id(ctx->msg),
+		.instance = instance,
+	};
+
+	state->key = tdb_data_talloc_copy(state, rec->key);
+	if (tevent_req_nomem(state->key.dptr, req)) {
+		return tevent_req_post(req, ev);
+	}
+
+	subreq = messaging_filtered_read_send(
+		state, ev, ctx->msg, dbwrap_watched_msg_filter, state);
+	if (tevent_req_nomem(subreq, req)) {
+		return tevent_req_post(req, ev);
+	}
+	tevent_req_set_callback(subreq, dbwrap_watched_watch_done, req);
+
+	talloc_set_destructor(state, dbwrap_watched_watch_state_destructor);
+
+	if (blocker.pid != 0) {
+		subreq = server_id_watch_send(state, ev, blocker);
+		if (tevent_req_nomem(subreq, req)) {
+			return tevent_req_post(req, ev);
+		}
+		tevent_req_set_callback(
+			subreq, dbwrap_watched_watch_blocker_died, req);
+	}
+
+	return req;
+}
+
+static void dbwrap_watched_watch_blocker_died(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(
+		subreq, struct tevent_req);
+	struct dbwrap_watched_watch_state *state = tevent_req_data(
+		req, struct dbwrap_watched_watch_state);
+	int ret;
+
+	ret = server_id_watch_recv(subreq, NULL);
+	TALLOC_FREE(subreq);
+	if (ret != 0) {
+		tevent_req_nterror(req, map_nt_error_from_unix(ret));
+		return;
+	}
+	state->blockerdead = true;
+	tevent_req_done(req);
+}
+
+static void dbwrap_watched_watch_state_destructor_fn(
+	struct db_record *rec,
+	TDB_DATA value,
+	void *private_data)
+{
+	struct dbwrap_watched_watch_state *state = talloc_get_type_abort(
+		private_data, struct dbwrap_watched_watch_state);
+
+	/*
+	 * Here we just remove ourself from the in memory
+	 * watchers array and let db_watched_record_fini()
+	 * call dbwrap_watched_record_storev() to do the magic
+	 * of writing back the modified in memory copy.
+	 */
+	dbwrap_watched_watch_remove_instance(rec, state->watcher.instance);
+	return;
+}
+
+static int dbwrap_watched_watch_state_destructor(
+	struct dbwrap_watched_watch_state *state)
+{
+	NTSTATUS status;
+
+	status = dbwrap_do_locked(
+		state->db,
+		state->key,
+		dbwrap_watched_watch_state_destructor_fn,
+		state);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_WARNING("dbwrap_do_locked failed: %s\n",
+			    nt_errstr(status));
+	}
+	return 0;
+}
+
+static bool dbwrap_watched_msg_filter(struct messaging_rec *rec,
+				      void *private_data)
+{
+	struct dbwrap_watched_watch_state *state = talloc_get_type_abort(
+		private_data, struct dbwrap_watched_watch_state);
+	uint64_t instance;
+
+	if (rec->msg_type != MSG_DBWRAP_MODIFIED) {
+		return false;
+	}
+	if (rec->num_fds != 0) {
+		return false;
+	}
+
+	if (rec->buf.length != sizeof(instance)) {
+		DBG_DEBUG("Got size %zu, expected %zu\n",
+			  rec->buf.length,
+			  sizeof(instance));
+		return false;
+	}
+
+	instance = BVAL(rec->buf.data, 0);
+
+	if (instance != state->watcher.instance) {
+		DBG_DEBUG("Got instance %"PRIu64", expected %"PRIu64"\n",
+			  instance,
+			  state->watcher.instance);
+		return false;
+	}
+
+	return true;
+}
+
+static void dbwrap_watched_watch_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(
+		subreq, struct tevent_req);
+	struct dbwrap_watched_watch_state *state = tevent_req_data(
+		req, struct dbwrap_watched_watch_state);
+	struct messaging_rec *rec;
+	int ret;
+
+	ret = messaging_filtered_read_recv(subreq, state, &rec);
+	TALLOC_FREE(subreq);
+	if (ret != 0) {
+		tevent_req_nterror(req, map_nt_error_from_unix(ret));
+		return;
+	}
+	tevent_req_done(req);
+}
+
+NTSTATUS dbwrap_watched_watch_recv(struct tevent_req *req,
+				   uint64_t *pkeep_instance,
+				   bool *blockerdead,
+				   struct server_id *blocker)
+{
+	struct dbwrap_watched_watch_state *state = tevent_req_data(
+		req, struct dbwrap_watched_watch_state);
+	NTSTATUS status;
+
+	if (tevent_req_is_nterror(req, &status)) {
+		tevent_req_received(req);
+		return status;
+	}
+	if (pkeep_instance != NULL) {
+		*pkeep_instance = state->watcher.instance;
+		/*
+		 * No need to remove ourselves anymore,
+		 * the caller will take care of removing itself.
+		 */
+		talloc_set_destructor(state, NULL);
+	}
+	if (blockerdead != NULL) {
+		*blockerdead = state->blockerdead;
+	}
+	if (blocker != NULL) {
+		*blocker = state->blocker;
+	}
+	tevent_req_received(req);
+	return NT_STATUS_OK;
+}
+
diff --git a/source3/lib/dbwrap/dbwrap_watch.h b/source3/lib/dbwrap/dbwrap_watch.h
new file mode 100644
index 0000000..1b93e13
--- /dev/null
+++ b/source3/lib/dbwrap/dbwrap_watch.h
@@ -0,0 +1,45 @@
+/*
+   Unix SMB/CIFS implementation.
+   Watch dbwrap record changes
+   Copyright (C) Volker Lendecke 2012
+
+   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/>.
+*/
+
+#ifndef __DBWRAP_WATCH_H__
+#define __DBWRAP_WATCH_H__
+
+#include <tevent.h>
+#include "dbwrap/dbwrap.h"
+#include "messages.h"
+
+struct db_context *db_open_watched(TALLOC_CTX *mem_ctx,
+				   struct db_context **backend,
+				   struct messaging_context *msg);
+uint64_t dbwrap_watched_watch_add_instance(struct db_record *rec);
+void dbwrap_watched_watch_remove_instance(struct db_record *rec, uint64_t instance);
+void dbwrap_watched_watch_skip_alerting(struct db_record *rec);
+void dbwrap_watched_watch_reset_alerting(struct db_record *rec);
+void dbwrap_watched_watch_force_alerting(struct db_record *rec);
+struct tevent_req *dbwrap_watched_watch_send(TALLOC_CTX *mem_ctx,
+					     struct tevent_context *ev,
+					     struct db_record *rec,
+					     uint64_t resume_instance,
+					     struct server_id blocker);
+NTSTATUS dbwrap_watched_watch_recv(struct tevent_req *req,
+				   uint64_t *pkeep_instance,
+				   bool *blockerdead,
+				   struct server_id *blocker);
+
+#endif /* __DBWRAP_WATCH_H__ */