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

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

1 files changed, 2517 insertions, 0 deletions

diff --git a/source3/locking/share_mode_lock.c b/source3/locking/share_mode_lock.c
new file mode 100644
index 0000000..75912ec
--- /dev/null
+++ b/source3/locking/share_mode_lock.c
@@ -0,0 +1,2517 @@
+/*
+   Unix SMB/CIFS implementation.
+   Locking functions
+   Copyright (C) Andrew Tridgell 1992-2000
+   Copyright (C) Jeremy Allison 1992-2006
+   Copyright (C) Volker Lendecke 2005
+
+   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/>.
+
+   Revision History:
+
+   12 aug 96: Erik.Devriendt@te6.siemens.be
+   added support for shared memory implementation of share mode locking
+
+   May 1997. Jeremy Allison (jallison@whistle.com). Modified share mode
+   locking to deal with multiple share modes per open file.
+
+   September 1997. Jeremy Allison (jallison@whistle.com). Added oplock
+   support.
+
+   rewritten completely to use new tdb code. Tridge, Dec '99
+
+   Added POSIX locking support. Jeremy Allison (jeremy@valinux.com), Apr. 2000.
+   Added Unix Extensions POSIX locking support. Jeremy Allison Mar 2006.
+*/
+
+#include "includes.h"
+#include "system/filesys.h"
+#include "lib/util/server_id.h"
+#include "share_mode_lock.h"
+#include "share_mode_lock_private.h"
+#include "locking/proto.h"
+#include "smbd/globals.h"
+#include "dbwrap/dbwrap.h"
+#include "dbwrap/dbwrap_open.h"
+#include "dbwrap/dbwrap_private.h"
+#include "../libcli/security/security.h"
+#include "serverid.h"
+#include "messages.h"
+#include "util_tdb.h"
+#include "../librpc/gen_ndr/ndr_open_files.h"
+#include "source3/lib/dbwrap/dbwrap_watch.h"
+#include "locking/leases_db.h"
+#include "../lib/util/memcache.h"
+#include "lib/util/tevent_ntstatus.h"
+#include "g_lock.h"
+#include "smbd/fd_handle.h"
+#include "lib/global_contexts.h"
+
+#undef DBGC_CLASS
+#define DBGC_CLASS DBGC_LOCKING
+
+#define NO_LOCKING_COUNT (-1)
+
+/* the locking database handle */
+static struct g_lock_ctx *lock_ctx;
+
+static bool locking_init_internal(bool read_only)
+{
+	struct db_context *backend;
+	char *db_path;
+
+	brl_init(read_only);
+
+	if (lock_ctx != NULL) {
+		return True;
+	}
+
+	db_path = lock_path(talloc_tos(), "locking.tdb");
+	if (db_path == NULL) {
+		return false;
+	}
+
+	backend = db_open(NULL, db_path,
+			  SMB_OPEN_DATABASE_TDB_HASH_SIZE,
+			  TDB_DEFAULT|
+			  TDB_VOLATILE|
+			  TDB_CLEAR_IF_FIRST|
+			  TDB_INCOMPATIBLE_HASH|
+			  TDB_SEQNUM,
+			  read_only?O_RDONLY:O_RDWR|O_CREAT, 0644,
+			  DBWRAP_LOCK_ORDER_NONE,
+			  DBWRAP_FLAG_NONE);
+	TALLOC_FREE(db_path);
+	if (!backend) {
+		DEBUG(0,("ERROR: Failed to initialise locking database\n"));
+		return False;
+	}
+
+	lock_ctx = g_lock_ctx_init_backend(
+		NULL, global_messaging_context(), &backend);
+	if (lock_ctx == NULL) {
+		TALLOC_FREE(backend);
+		return false;
+	}
+	g_lock_set_lock_order(lock_ctx, DBWRAP_LOCK_ORDER_1);
+
+	if (!posix_locking_init(read_only)) {
+		TALLOC_FREE(lock_ctx);
+		return False;
+	}
+
+	return True;
+}
+
+bool locking_init(void)
+{
+	return locking_init_internal(false);
+}
+
+bool locking_init_readonly(void)
+{
+	return locking_init_internal(true);
+}
+
+/*******************************************************************
+ Deinitialize the share_mode management.
+******************************************************************/
+
+bool locking_end(void)
+{
+	brl_shutdown();
+	TALLOC_FREE(lock_ctx);
+	return true;
+}
+
+/*******************************************************************
+ Form a static locking key for a dev/inode pair.
+******************************************************************/
+
+static TDB_DATA locking_key(const struct file_id *id)
+{
+	return make_tdb_data((const uint8_t *)id, sizeof(*id));
+}
+
+/*******************************************************************
+ Share mode cache utility functions that store/delete/retrieve
+ entries from memcache.
+
+ For now share the statcache (global cache) memory space. If
+ a lock record gets orphaned (which shouldn't happen as we're
+ using the same locking_key data as lookup) it will eventually
+ fall out of the cache via the normal LRU trim mechanism. If
+ necessary we can always make this a separate (smaller) cache.
+******************************************************************/
+
+static DATA_BLOB memcache_key(const struct file_id *id)
+{
+	return data_blob_const((const void *)id, sizeof(*id));
+}
+
+static void share_mode_memcache_store(struct share_mode_data *d)
+{
+	const DATA_BLOB key = memcache_key(&d->id);
+	struct file_id_buf idbuf;
+
+	DBG_DEBUG("stored entry for file %s epoch %"PRIx64" key %s\n",
+		  d->base_name,
+		  d->unique_content_epoch,
+		  file_id_str_buf(d->id, &idbuf));
+
+	/* Ensure everything stored in the cache is pristine. */
+	d->modified = false;
+	d->fresh = false;
+
+	/*
+	 * Ensure the memory going into the cache
+	 * doesn't have a destructor so it can be
+	 * cleanly evicted by the memcache LRU
+	 * mechanism.
+	 */
+	talloc_set_destructor(d, NULL);
+
+	/* Cache will own d after this call. */
+	memcache_add_talloc(NULL,
+			SHARE_MODE_LOCK_CACHE,
+			key,
+			&d);
+}
+
+/*
+ * NB. We use ndr_pull_hyper on a stack-created
+ * struct ndr_pull with no talloc allowed, as we
+ * need this to be really fast as an ndr-peek into
+ * the first 10 bytes of the blob.
+ */
+
+static enum ndr_err_code get_share_mode_blob_header(
+	const uint8_t *buf, size_t buflen, uint64_t *pepoch, uint16_t *pflags)
+{
+	struct ndr_pull ndr = {
+		.data = discard_const_p(uint8_t, buf),
+		.data_size = buflen,
+	};
+	NDR_CHECK(ndr_pull_hyper(&ndr, NDR_SCALARS, pepoch));
+	NDR_CHECK(ndr_pull_uint16(&ndr, NDR_SCALARS, pflags));
+	return NDR_ERR_SUCCESS;
+}
+
+struct fsp_update_share_mode_flags_state {
+	enum ndr_err_code ndr_err;
+	uint16_t share_mode_flags;
+};
+
+static void fsp_update_share_mode_flags_fn(
+	const uint8_t *buf,
+	size_t buflen,
+	bool *modified_dependent,
+	void *private_data)
+{
+	struct fsp_update_share_mode_flags_state *state = private_data;
+	uint64_t seq;
+
+	state->ndr_err = get_share_mode_blob_header(
+		buf, buflen, &seq, &state->share_mode_flags);
+}
+
+static NTSTATUS fsp_update_share_mode_flags(struct files_struct *fsp)
+{
+	struct fsp_update_share_mode_flags_state state = {0};
+	int seqnum = g_lock_seqnum(lock_ctx);
+	NTSTATUS status;
+
+	if (seqnum == fsp->share_mode_flags_seqnum) {
+		return NT_STATUS_OK;
+	}
+
+	status = share_mode_do_locked(
+		fsp->file_id, fsp_update_share_mode_flags_fn, &state);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("share_mode_do_locked returned %s\n",
+			  nt_errstr(status));
+		return status;
+	}
+
+	if (!NDR_ERR_CODE_IS_SUCCESS(state.ndr_err)) {
+		DBG_DEBUG("get_share_mode_blob_header returned %s\n",
+			  ndr_errstr(state.ndr_err));
+		return ndr_map_error2ntstatus(state.ndr_err);
+	}
+
+	fsp->share_mode_flags_seqnum = seqnum;
+	fsp->share_mode_flags = state.share_mode_flags;
+
+	return NT_STATUS_OK;
+}
+
+bool file_has_read_lease(struct files_struct *fsp)
+{
+	NTSTATUS status;
+
+	status = fsp_update_share_mode_flags(fsp);
+	if (!NT_STATUS_IS_OK(status)) {
+		/* Safe default for leases */
+		return true;
+	}
+
+	return (fsp->share_mode_flags & SHARE_MODE_LEASE_READ) != 0;
+}
+
+static int share_mode_data_nofree_destructor(struct share_mode_data *d)
+{
+	return -1;
+}
+
+static struct share_mode_data *share_mode_memcache_fetch(
+	TALLOC_CTX *mem_ctx,
+	struct file_id id,
+	const uint8_t *buf,
+	size_t buflen)
+{
+	const DATA_BLOB key = memcache_key(&id);
+	enum ndr_err_code ndr_err;
+	struct share_mode_data *d;
+	uint64_t unique_content_epoch;
+	uint16_t flags;
+	void *ptr;
+	struct file_id_buf idbuf;
+
+	ptr = memcache_lookup_talloc(NULL,
+			SHARE_MODE_LOCK_CACHE,
+			key);
+	if (ptr == NULL) {
+		DBG_DEBUG("failed to find entry for key %s\n",
+			  file_id_str_buf(id, &idbuf));
+		return NULL;
+	}
+	/* sequence number key is at start of blob. */
+	ndr_err = get_share_mode_blob_header(
+		buf, buflen, &unique_content_epoch, &flags);
+	if (ndr_err != NDR_ERR_SUCCESS) {
+		/* Bad blob. Remove entry. */
+		DBG_DEBUG("bad blob %u key %s\n",
+			  (unsigned int)ndr_err,
+			  file_id_str_buf(id, &idbuf));
+		memcache_delete(NULL,
+			SHARE_MODE_LOCK_CACHE,
+			key);
+		return NULL;
+	}
+
+	d = (struct share_mode_data *)ptr;
+	if (d->unique_content_epoch != unique_content_epoch) {
+		DBG_DEBUG("epoch changed (cached %"PRIx64") (new %"PRIx64") "
+			  "for key %s\n",
+			  d->unique_content_epoch,
+			  unique_content_epoch,
+			  file_id_str_buf(id, &idbuf));
+		/* Cache out of date. Remove entry. */
+		memcache_delete(NULL,
+			SHARE_MODE_LOCK_CACHE,
+			key);
+		return NULL;
+	}
+
+	/* Move onto mem_ctx. */
+	d = talloc_move(mem_ctx, &ptr);
+
+	/*
+	 * Now we own d, prevent the cache from freeing it
+	 * when we delete the entry.
+	 */
+	talloc_set_destructor(d, share_mode_data_nofree_destructor);
+
+	/* Remove from the cache. We own it now. */
+	memcache_delete(NULL,
+			SHARE_MODE_LOCK_CACHE,
+			key);
+
+	/* And reset the destructor to none. */
+	talloc_set_destructor(d, NULL);
+
+	DBG_DEBUG("fetched entry for file %s epoch %"PRIx64" key %s\n",
+		  d->base_name,
+		  d->unique_content_epoch,
+		  file_id_str_buf(id, &idbuf));
+
+	return d;
+}
+
+/*
+ * 132 is the sizeof an ndr-encoded struct share_mode_entry_buf.
+ * Reading/writing entries will immediately error out if this
+ * size differs (push/pull is done without allocs).
+ */
+
+struct share_mode_entry_buf {
+	uint8_t buf[132];
+};
+#define SHARE_MODE_ENTRY_SIZE (sizeof(struct share_mode_entry_buf))
+
+static bool share_mode_entry_put(
+	const struct share_mode_entry *e,
+	struct share_mode_entry_buf *dst)
+{
+	DATA_BLOB blob = { .data = dst->buf, .length = sizeof(dst->buf) };
+	enum ndr_err_code ndr_err;
+
+	if (DEBUGLEVEL>=10) {
+		DBG_DEBUG("share_mode_entry:\n");
+		NDR_PRINT_DEBUG(share_mode_entry, discard_const_p(void, e));
+	}
+
+	ndr_err = ndr_push_struct_into_fixed_blob(
+		&blob,
+		e,
+		(ndr_push_flags_fn_t)ndr_push_share_mode_entry);
+	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+		DBG_WARNING("ndr_push_share_mode_entry failed: %s\n",
+			    ndr_errstr(ndr_err));
+		return false;
+	}
+
+	return true;
+}
+
+static bool share_mode_entry_get(
+	const uint8_t ptr[SHARE_MODE_ENTRY_SIZE], struct share_mode_entry *e)
+{
+	enum ndr_err_code ndr_err = NDR_ERR_SUCCESS;
+	DATA_BLOB blob = {
+		.data = discard_const_p(uint8_t, ptr),
+		.length = SHARE_MODE_ENTRY_SIZE,
+	};
+
+	ndr_err = ndr_pull_struct_blob_all_noalloc(
+		&blob, e, (ndr_pull_flags_fn_t)ndr_pull_share_mode_entry);
+	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+		DBG_WARNING("ndr_pull_share_mode_entry failed\n");
+		return false;
+	}
+	return true;
+}
+
+/*
+ * locking.tdb records consist of
+ *
+ * uint32_t share_mode_data_len
+ * uint8_t [share_mode_data]       This is struct share_mode_data in NDR
+ *
+ * 0 [SHARE_MODE_ENTRY_SIZE]       Sorted array of share modes,
+ * 1 [SHARE_MODE_ENTRY_SIZE]       filling up the rest of the data in the
+ * 2 [SHARE_MODE_ENTRY_SIZE]       g_lock.c maintained record in locking.tdb
+ */
+
+struct locking_tdb_data {
+	const uint8_t *share_mode_data_buf;
+	size_t share_mode_data_len;
+	const uint8_t *share_entries;
+	size_t num_share_entries;
+};
+
+static bool locking_tdb_data_get(
+	struct locking_tdb_data *data, const uint8_t *buf, size_t buflen)
+{
+	uint32_t share_mode_data_len, share_entries_len;
+
+	if (buflen == 0) {
+		*data = (struct locking_tdb_data) { 0 };
+		return true;
+	}
+	if (buflen < sizeof(uint32_t)) {
+		return false;
+	}
+
+	share_mode_data_len = PULL_LE_U32(buf, 0);
+
+	buf += sizeof(uint32_t);
+	buflen -= sizeof(uint32_t);
+
+	if (buflen < share_mode_data_len) {
+		return false;
+	}
+
+	share_entries_len = buflen - share_mode_data_len;
+
+	if ((share_entries_len % SHARE_MODE_ENTRY_SIZE) != 0) {
+		return false;
+	}
+
+	*data = (struct locking_tdb_data) {
+		.share_mode_data_buf = buf,
+		.share_mode_data_len = share_mode_data_len,
+		.share_entries = buf + share_mode_data_len,
+		.num_share_entries = share_entries_len / SHARE_MODE_ENTRY_SIZE,
+	};
+
+	return true;
+}
+
+struct locking_tdb_data_fetch_state {
+	TALLOC_CTX *mem_ctx;
+	uint8_t *data;
+	size_t datalen;
+};
+
+static void locking_tdb_data_fetch_fn(
+	struct server_id exclusive,
+	size_t num_shared,
+	const struct server_id *shared,
+	const uint8_t *data,
+	size_t datalen,
+	void *private_data)
+{
+	struct locking_tdb_data_fetch_state *state = private_data;
+	state->datalen = datalen;
+	state->data = talloc_memdup(state->mem_ctx, data, datalen);
+}
+
+static NTSTATUS locking_tdb_data_fetch(
+	TDB_DATA key, TALLOC_CTX *mem_ctx, struct locking_tdb_data **ltdb)
+{
+	struct locking_tdb_data_fetch_state state = { 0 };
+	struct locking_tdb_data *result = NULL;
+	NTSTATUS status;
+	bool ok;
+
+	result = talloc_zero(mem_ctx, struct locking_tdb_data);
+	if (result == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	state.mem_ctx = result;
+
+	status = g_lock_dump(lock_ctx, key, locking_tdb_data_fetch_fn, &state);
+
+	if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) {
+		/*
+		 * Just return an empty record
+		 */
+		goto done;
+	}
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("g_lock_dump failed: %s\n", nt_errstr(status));
+		return status;
+	}
+	if (state.datalen == 0) {
+		goto done;
+	}
+
+	ok = locking_tdb_data_get(result, state.data, state.datalen);
+	if (!ok) {
+		DBG_DEBUG("locking_tdb_data_get failed for %zu bytes\n",
+			  state.datalen);
+		TALLOC_FREE(result);
+		return NT_STATUS_INTERNAL_DB_CORRUPTION;
+	}
+
+done:
+	*ltdb = result;
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS locking_tdb_data_store(
+	TDB_DATA key,
+	const struct locking_tdb_data *ltdb,
+	const TDB_DATA *share_mode_dbufs,
+	size_t num_share_mode_dbufs)
+{
+	uint8_t share_mode_data_len_buf[4];
+	TDB_DATA dbufs[num_share_mode_dbufs+3];
+	NTSTATUS status;
+
+	if ((ltdb->share_mode_data_len == 0) &&
+	    (ltdb->num_share_entries == 0) &&
+	    (num_share_mode_dbufs == 0)) {
+		/*
+		 * Nothing to write
+		 */
+		status = g_lock_write_data(lock_ctx, key, NULL, 0);
+		if (!NT_STATUS_IS_OK(status)) {
+			DBG_DEBUG("g_lock_writev_data() failed: %s\n",
+				  nt_errstr(status));
+		}
+		return status;
+	}
+
+	PUSH_LE_U32(share_mode_data_len_buf, 0, ltdb->share_mode_data_len);
+
+	dbufs[0] = (TDB_DATA) {
+		.dptr = share_mode_data_len_buf,
+		.dsize = sizeof(share_mode_data_len_buf),
+	};
+	dbufs[1] = (TDB_DATA) {
+		.dptr = discard_const_p(uint8_t, ltdb->share_mode_data_buf),
+		.dsize = ltdb->share_mode_data_len,
+	};
+
+	if (ltdb->num_share_entries > SIZE_MAX/SHARE_MODE_ENTRY_SIZE) {
+		/* overflow */
+		return NT_STATUS_BUFFER_OVERFLOW;
+	}
+	dbufs[2] = (TDB_DATA) {
+		.dptr = discard_const_p(uint8_t, ltdb->share_entries),
+		.dsize = ltdb->num_share_entries * SHARE_MODE_ENTRY_SIZE,
+	};
+
+	if (num_share_mode_dbufs != 0) {
+		memcpy(&dbufs[3],
+		       share_mode_dbufs,
+		       num_share_mode_dbufs * sizeof(TDB_DATA));
+	}
+
+	status = g_lock_writev_data(lock_ctx, key, dbufs, ARRAY_SIZE(dbufs));
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("g_lock_writev_data() failed: %s\n",
+			  nt_errstr(status));
+	}
+	return status;
+}
+
+/*******************************************************************
+ Get all share mode entries for a dev/inode pair.
+********************************************************************/
+
+static struct share_mode_data *parse_share_modes(
+	TALLOC_CTX *mem_ctx,
+	struct file_id id,
+	const uint8_t *buf,
+	size_t buflen)
+{
+	struct share_mode_data *d;
+	enum ndr_err_code ndr_err;
+	DATA_BLOB blob;
+
+	/* See if we already have a cached copy of this key. */
+	d = share_mode_memcache_fetch(mem_ctx, id, buf, buflen);
+	if (d != NULL) {
+		return d;
+	}
+
+	d = talloc(mem_ctx, struct share_mode_data);
+	if (d == NULL) {
+		DEBUG(0, ("talloc failed\n"));
+		goto fail;
+	}
+
+	blob = (DATA_BLOB) {
+		.data = discard_const_p(uint8_t, buf),
+		.length = buflen,
+	};
+	ndr_err = ndr_pull_struct_blob_all(
+		&blob, d, d, (ndr_pull_flags_fn_t)ndr_pull_share_mode_data);
+	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+		DBG_WARNING("ndr_pull_share_mode_data failed: %s\n",
+			    ndr_errstr(ndr_err));
+		goto fail;
+	}
+
+	if (DEBUGLEVEL >= 10) {
+		DEBUG(10, ("parse_share_modes:\n"));
+		NDR_PRINT_DEBUG(share_mode_data, d);
+	}
+
+	return d;
+fail:
+	TALLOC_FREE(d);
+	return NULL;
+}
+
+/*******************************************************************
+ If modified, store the share_mode_data back into the database.
+********************************************************************/
+
+static NTSTATUS share_mode_data_store(
+	struct share_mode_data *d, bool *have_share_entries)
+{
+	TDB_DATA key = locking_key(&d->id);
+	struct locking_tdb_data *ltdb = NULL;
+	DATA_BLOB blob = { 0 };
+	NTSTATUS status;
+
+	if (!d->modified) {
+		DBG_DEBUG("not modified\n");
+		return NT_STATUS_OK;
+	}
+
+	if (DEBUGLEVEL >= 10) {
+		DBG_DEBUG("\n");
+		NDR_PRINT_DEBUG(share_mode_data, d);
+	}
+
+	d->unique_content_epoch = generate_unique_u64(d->unique_content_epoch);
+
+	status = locking_tdb_data_fetch(key, d, &ltdb);
+	if (!NT_STATUS_IS_OK(status)) {
+		return status;
+	}
+
+	if (ltdb->num_share_entries != 0) {
+		enum ndr_err_code ndr_err;
+
+		ndr_err = ndr_push_struct_blob(
+			&blob,
+			ltdb,
+			d,
+			(ndr_push_flags_fn_t)ndr_push_share_mode_data);
+		if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+			DBG_DEBUG("ndr_push_share_mode_data failed: %s\n",
+				  ndr_errstr(ndr_err));
+			TALLOC_FREE(ltdb);
+			return ndr_map_error2ntstatus(ndr_err);
+		}
+
+		*have_share_entries = true;
+	}
+
+	ltdb->share_mode_data_buf = blob.data;
+	ltdb->share_mode_data_len = blob.length;
+
+	status = locking_tdb_data_store(key, ltdb, NULL, 0);
+	TALLOC_FREE(ltdb);
+	return status;
+}
+
+/*******************************************************************
+ Allocate a new share_mode_data struct, mark it unmodified.
+ fresh is set to note that currently there is no database entry.
+********************************************************************/
+
+static struct share_mode_data *fresh_share_mode_lock(
+	TALLOC_CTX *mem_ctx, const char *servicepath,
+	const struct smb_filename *smb_fname,
+	const struct timespec *old_write_time)
+{
+	struct share_mode_data *d;
+
+	if ((servicepath == NULL) || (smb_fname == NULL) ||
+	    (old_write_time == NULL)) {
+		return NULL;
+	}
+
+	d = talloc_zero(mem_ctx, struct share_mode_data);
+	if (d == NULL) {
+		goto fail;
+	}
+	d->unique_content_epoch = generate_unique_u64(0);
+
+	d->base_name = talloc_strdup(d, smb_fname->base_name);
+	if (d->base_name == NULL) {
+		goto fail;
+	}
+	if (smb_fname->stream_name != NULL) {
+		d->stream_name = talloc_strdup(d, smb_fname->stream_name);
+		if (d->stream_name == NULL) {
+			goto fail;
+		}
+	}
+	d->servicepath = talloc_strdup(d, servicepath);
+	if (d->servicepath == NULL) {
+		goto fail;
+	}
+	d->old_write_time = full_timespec_to_nt_time(old_write_time);
+	d->flags = SHARE_MODE_SHARE_DELETE |
+		SHARE_MODE_SHARE_WRITE |
+		SHARE_MODE_SHARE_READ;
+	d->modified = false;
+	d->fresh = true;
+	return d;
+fail:
+	DEBUG(0, ("talloc failed\n"));
+	TALLOC_FREE(d);
+	return NULL;
+}
+
+/*
+ * Key that's locked with g_lock
+ */
+static uint8_t share_mode_lock_key_data[sizeof(struct file_id)];
+static TDB_DATA share_mode_lock_key = {
+	.dptr = share_mode_lock_key_data,
+	.dsize = sizeof(share_mode_lock_key_data),
+};
+static size_t share_mode_lock_key_refcount = 0;
+
+/*
+ * We can only ever have one share mode locked. Use a static
+ * share_mode_data pointer that is shared by multiple nested
+ * share_mode_lock structures, explicitly refcounted.
+ */
+static struct share_mode_data *static_share_mode_data = NULL;
+static size_t static_share_mode_data_refcount = 0;
+
+/*******************************************************************
+ Either fetch a share mode from the database, or allocate a fresh
+ one if the record doesn't exist.
+********************************************************************/
+
+struct get_static_share_mode_data_state {
+	TALLOC_CTX *mem_ctx;
+	struct file_id id;
+	const char *servicepath;
+	const struct smb_filename *smb_fname;
+	const struct timespec *old_write_time;
+	NTSTATUS status;
+};
+
+static void get_static_share_mode_data_fn(
+	struct server_id exclusive,
+	size_t num_shared,
+	const struct server_id *shared,
+	const uint8_t *data,
+	size_t datalen,
+	void *private_data)
+{
+	struct get_static_share_mode_data_state *state = private_data;
+	struct share_mode_data *d = NULL;
+	struct locking_tdb_data ltdb = { 0 };
+
+	if (datalen != 0) {
+		bool ok;
+
+		ok = locking_tdb_data_get(&ltdb, data, datalen);
+		if (!ok) {
+			DBG_DEBUG("locking_tdb_data_get failed\n");
+			state->status = NT_STATUS_INTERNAL_DB_CORRUPTION;
+			return;
+		}
+	}
+
+	if (ltdb.share_mode_data_len == 0) {
+		if (state->smb_fname == NULL) {
+			state->status = NT_STATUS_NOT_FOUND;
+			return;
+		}
+		d = fresh_share_mode_lock(
+			state->mem_ctx,
+			state->servicepath,
+			state->smb_fname,
+			state->old_write_time);
+		if (d == NULL) {
+			state->status = NT_STATUS_NO_MEMORY;
+			return;
+		}
+	} else {
+		d = parse_share_modes(
+			lock_ctx,
+			state->id,
+			ltdb.share_mode_data_buf,
+			ltdb.share_mode_data_len);
+		if (d == NULL) {
+			state->status = NT_STATUS_INTERNAL_DB_CORRUPTION;
+			return;
+		}
+	}
+
+	d->id = state->id;
+	static_share_mode_data = d;
+}
+
+static NTSTATUS get_static_share_mode_data(
+	struct file_id id,
+	const char *servicepath,
+	const struct smb_filename *smb_fname,
+	const struct timespec *old_write_time)
+{
+	struct get_static_share_mode_data_state state = {
+		.mem_ctx = lock_ctx,
+		.id = id,
+		.servicepath = servicepath,
+		.smb_fname = smb_fname,
+		.old_write_time = old_write_time,
+	};
+	NTSTATUS status;
+
+	SMB_ASSERT(static_share_mode_data == NULL);
+
+	status = g_lock_dump(
+		lock_ctx,
+		share_mode_lock_key,
+		get_static_share_mode_data_fn,
+		&state);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("g_lock_dump failed: %s\n",
+			  nt_errstr(status));
+		return status;
+	}
+	if (!NT_STATUS_IS_OK(state.status)) {
+		DBG_DEBUG("get_static_share_mode_data_fn failed: %s\n",
+			  nt_errstr(state.status));
+		return state.status;
+	}
+
+	return NT_STATUS_OK;
+}
+
+/*******************************************************************
+ Get a share_mode_lock, Reference counted to allow nested calls.
+********************************************************************/
+
+static int share_mode_lock_destructor(struct share_mode_lock *lck);
+
+struct share_mode_lock *get_share_mode_lock(
+	TALLOC_CTX *mem_ctx,
+	struct file_id id,
+	const char *servicepath,
+	const struct smb_filename *smb_fname,
+	const struct timespec *old_write_time)
+{
+	TDB_DATA key = locking_key(&id);
+	struct share_mode_lock *lck = NULL;
+	NTSTATUS status;
+	int cmp;
+
+	lck = talloc(mem_ctx, struct share_mode_lock);
+	if (lck == NULL) {
+		DEBUG(1, ("talloc failed\n"));
+		return NULL;
+	}
+
+	if (static_share_mode_data != NULL) {
+		if (!file_id_equal(&static_share_mode_data->id, &id)) {
+			struct file_id_buf existing;
+			struct file_id_buf requested;
+
+			DBG_ERR("Can not lock two share modes "
+				"simultaneously: existing %s requested %s\n",
+				file_id_str_buf(static_share_mode_data->id, &existing),
+				file_id_str_buf(id, &requested));
+
+			smb_panic(__location__);
+			goto fail;
+		}
+		goto done;
+	}
+
+	if (share_mode_lock_key_refcount == 0) {
+		status = g_lock_lock(
+			lock_ctx,
+			key,
+			G_LOCK_WRITE,
+			(struct timeval) { .tv_sec = 3600 });
+		if (!NT_STATUS_IS_OK(status)) {
+			DBG_DEBUG("g_lock_lock failed: %s\n",
+				  nt_errstr(status));
+			goto fail;
+		}
+		memcpy(share_mode_lock_key_data, key.dptr, key.dsize);
+	}
+
+	cmp = tdb_data_cmp(share_mode_lock_key, key);
+	if (cmp != 0) {
+		DBG_WARNING("Can not lock two share modes simultaneously\n");
+		smb_panic(__location__);
+		goto fail;
+	}
+
+	SMB_ASSERT(share_mode_lock_key_refcount < SIZE_MAX);
+	share_mode_lock_key_refcount += 1;
+
+	SMB_ASSERT(static_share_mode_data_refcount == 0);
+
+	status = get_static_share_mode_data(
+		id,
+		servicepath,
+		smb_fname,
+		old_write_time);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("get_static_share_mode_data failed: %s\n",
+			  nt_errstr(status));
+		share_mode_lock_key_refcount -= 1;
+		goto fail;
+	}
+done:
+	static_share_mode_data_refcount += 1;
+	lck->data = static_share_mode_data;
+
+	talloc_set_destructor(lck, share_mode_lock_destructor);
+
+	if (CHECK_DEBUGLVL(DBGLVL_DEBUG)) {
+		struct file_id_buf returned;
+
+		DBG_DEBUG("Returning %s (data_refcount=%zu key_refcount=%zu)\n",
+			  file_id_str_buf(id, &returned),
+			  static_share_mode_data_refcount,
+			  share_mode_lock_key_refcount);
+	}
+
+	return lck;
+fail:
+	TALLOC_FREE(lck);
+	if (share_mode_lock_key_refcount == 0) {
+		status = g_lock_unlock(lock_ctx, share_mode_lock_key);
+		if (!NT_STATUS_IS_OK(status)) {
+			DBG_ERR("g_lock_unlock failed: %s\n",
+				nt_errstr(status));
+		}
+	}
+	return NULL;
+}
+
+static int share_mode_lock_destructor(struct share_mode_lock *lck)
+{
+	bool have_share_entries = false;
+	NTSTATUS status;
+
+	SMB_ASSERT(static_share_mode_data_refcount > 0);
+	static_share_mode_data_refcount -= 1;
+
+	if (static_share_mode_data_refcount > 0) {
+		return 0;
+	}
+
+	status = share_mode_data_store(
+		static_share_mode_data, &have_share_entries);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_ERR("share_mode_data_store failed: %s\n",
+			nt_errstr(status));
+		smb_panic("Could not store share mode data\n");
+	}
+
+	SMB_ASSERT(share_mode_lock_key_refcount > 0);
+	share_mode_lock_key_refcount -= 1;
+
+	if (share_mode_lock_key_refcount == 0) {
+		status = g_lock_unlock(lock_ctx, share_mode_lock_key);
+		if (!NT_STATUS_IS_OK(status)) {
+			DBG_ERR("g_lock_unlock failed: %s\n",
+				nt_errstr(status));
+			smb_panic("Could not unlock share mode\n");
+		}
+	}
+
+	if (have_share_entries) {
+		/*
+		 * This is worth keeping. Without share modes,
+		 * share_mode_data_store above has left nothing in the
+		 * database.
+		 */
+		share_mode_memcache_store(static_share_mode_data);
+		static_share_mode_data = NULL;
+	}
+
+	TALLOC_FREE(static_share_mode_data);
+	return 0;
+}
+
+/*******************************************************************
+ Fetch a share mode where we know one MUST exist. This call reference
+ counts it internally to allow for nested lock fetches.
+********************************************************************/
+
+struct share_mode_lock *get_existing_share_mode_lock(TALLOC_CTX *mem_ctx,
+						     const struct file_id id)
+{
+	return get_share_mode_lock(mem_ctx, id, NULL, NULL, NULL);
+}
+
+struct share_mode_do_locked_state {
+	TDB_DATA key;
+	void (*fn)(const uint8_t *buf,
+		   size_t buflen,
+		   bool *modified_dependent,
+		   void *private_data);
+	void *private_data;
+};
+
+static void share_mode_do_locked_fn(
+	struct server_id exclusive,
+	size_t num_shared,
+	const struct server_id *shared,
+	const uint8_t *data,
+	size_t datalen,
+	void *private_data)
+{
+	struct share_mode_do_locked_state *state = private_data;
+	bool modified_dependent = false;
+	struct locking_tdb_data ltdb = { 0 };
+	bool ok;
+
+	ok = locking_tdb_data_get(
+		&ltdb, discard_const_p(uint8_t, data), datalen);
+	if (!ok) {
+		DBG_WARNING("locking_tdb_data_get failed\n");
+		return;
+	}
+
+	state->fn(ltdb.share_mode_data_buf,
+		  ltdb.share_mode_data_len,
+		  &modified_dependent,
+		  state->private_data);
+
+	if (modified_dependent) {
+		g_lock_wake_watchers(lock_ctx, state->key);
+	}
+}
+
+NTSTATUS share_mode_do_locked(
+	struct file_id id,
+	void (*fn)(const uint8_t *buf,
+		   size_t buflen,
+		   bool *modified_dependent,
+		   void *private_data),
+	void *private_data)
+{
+	TDB_DATA key = locking_key(&id);
+	size_t data_refcount, key_refcount;
+	struct share_mode_do_locked_state state = {
+		.key = key, .fn = fn, .private_data = private_data,
+	};
+	NTSTATUS status;
+
+	if (share_mode_lock_key_refcount == 0) {
+		status = g_lock_lock(
+			lock_ctx,
+			key,
+			G_LOCK_WRITE,
+			(struct timeval) { .tv_sec = 3600 });
+		if (!NT_STATUS_IS_OK(status)) {
+			DBG_DEBUG("g_lock_lock failed: %s\n",
+				  nt_errstr(status));
+			return status;
+		}
+		memcpy(share_mode_lock_key_data, key.dptr, key.dsize);
+	}
+
+	SMB_ASSERT(share_mode_lock_key_refcount < SIZE_MAX);
+	share_mode_lock_key_refcount += 1;
+
+	key_refcount = share_mode_lock_key_refcount;
+	data_refcount = static_share_mode_data_refcount;
+
+	status = g_lock_dump(
+		lock_ctx, key, share_mode_do_locked_fn, &state);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("g_lock_dump failed: %s\n",
+			  nt_errstr(status));
+	}
+
+	SMB_ASSERT(data_refcount == static_share_mode_data_refcount);
+	SMB_ASSERT(key_refcount == share_mode_lock_key_refcount);
+	share_mode_lock_key_refcount -= 1;
+
+	if (share_mode_lock_key_refcount == 0) {
+		status = g_lock_unlock(lock_ctx, key);
+		if (!NT_STATUS_IS_OK(status)) {
+			DBG_DEBUG("g_lock_unlock failed: %s\n",
+				  nt_errstr(status));
+		}
+	}
+
+	return status;
+}
+
+static void share_mode_wakeup_waiters_fn(
+	const uint8_t *buf,
+	size_t buflen,
+	bool *modified_dependent,
+	void *private_data)
+{
+	*modified_dependent = true;
+}
+
+NTSTATUS share_mode_wakeup_waiters(struct file_id id)
+{
+	return share_mode_do_locked(id, share_mode_wakeup_waiters_fn, NULL);
+}
+
+NTTIME share_mode_changed_write_time(struct share_mode_lock *lck)
+{
+	return lck->data->changed_write_time;
+}
+
+const char *share_mode_servicepath(struct share_mode_lock *lck)
+{
+	return lck->data->servicepath;
+}
+
+char *share_mode_filename(TALLOC_CTX *mem_ctx, struct share_mode_lock *lck)
+{
+	struct share_mode_data *d = lck->data;
+	bool has_stream = (d->stream_name != NULL);
+	char *fname = NULL;
+
+	fname = talloc_asprintf(
+		mem_ctx,
+		"%s%s%s",
+		d->base_name,
+		has_stream ? ":" : "",
+		has_stream ? d->stream_name : "");
+	return fname;
+}
+
+char *share_mode_data_dump(
+	TALLOC_CTX *mem_ctx, struct share_mode_lock *lck)
+{
+	struct ndr_print *p = talloc(mem_ctx, struct ndr_print);
+	char *ret = NULL;
+
+	if (p == NULL) {
+		return NULL;
+	}
+
+	*p = (struct ndr_print) {
+		.print = ndr_print_string_helper,
+		.depth = 1,
+		.private_data = talloc_strdup(mem_ctx, ""),
+	};
+
+	if (p->private_data == NULL) {
+		TALLOC_FREE(p);
+		return NULL;
+	}
+
+	ndr_print_share_mode_data(p, "SHARE_MODE_DATA", lck->data);
+
+	ret = p->private_data;
+
+	TALLOC_FREE(p);
+
+	return ret;
+}
+
+void share_mode_flags_get(
+	struct share_mode_lock *lck,
+	uint32_t *access_mask,
+	uint32_t *share_mode,
+	uint32_t *lease_type)
+{
+	uint16_t flags = lck->data->flags;
+
+	if (access_mask != NULL) {
+		*access_mask =
+			((flags & SHARE_MODE_ACCESS_READ) ?
+			 FILE_READ_DATA : 0) |
+			((flags & SHARE_MODE_ACCESS_WRITE) ?
+			 FILE_WRITE_DATA : 0) |
+			((flags & SHARE_MODE_ACCESS_DELETE) ?
+			 DELETE_ACCESS : 0);
+	}
+	if (share_mode != NULL) {
+		*share_mode =
+			((flags & SHARE_MODE_SHARE_READ) ?
+			 FILE_SHARE_READ : 0) |
+			((flags & SHARE_MODE_SHARE_WRITE) ?
+			 FILE_SHARE_WRITE : 0) |
+			((flags & SHARE_MODE_SHARE_DELETE) ?
+			 FILE_SHARE_DELETE : 0);
+	}
+	if (lease_type != NULL) {
+		*lease_type =
+			((flags & SHARE_MODE_LEASE_READ) ?
+			 SMB2_LEASE_READ : 0) |
+			((flags & SHARE_MODE_LEASE_WRITE) ?
+			 SMB2_LEASE_WRITE : 0) |
+			((flags & SHARE_MODE_LEASE_HANDLE) ?
+			 SMB2_LEASE_HANDLE : 0);
+	}
+}
+
+void share_mode_flags_set(
+	struct share_mode_lock *lck,
+	uint32_t access_mask,
+	uint32_t share_mode,
+	uint32_t lease_type,
+	bool *modified)
+{
+	struct share_mode_data *d = lck->data;
+	uint16_t flags = 0;
+
+	flags |= (access_mask & (FILE_READ_DATA | FILE_EXECUTE)) ?
+		SHARE_MODE_ACCESS_READ : 0;
+	flags |= (access_mask & (FILE_WRITE_DATA | FILE_APPEND_DATA)) ?
+		SHARE_MODE_ACCESS_WRITE : 0;
+	flags |= (access_mask & (DELETE_ACCESS)) ?
+		SHARE_MODE_ACCESS_DELETE : 0;
+
+	flags |= (share_mode & FILE_SHARE_READ) ?
+		SHARE_MODE_SHARE_READ : 0;
+	flags |= (share_mode & FILE_SHARE_WRITE) ?
+		SHARE_MODE_SHARE_WRITE : 0;
+	flags |= (share_mode & FILE_SHARE_DELETE) ?
+		SHARE_MODE_SHARE_DELETE : 0;
+
+	flags |= (lease_type & SMB2_LEASE_READ) ?
+		SHARE_MODE_LEASE_READ : 0;
+	flags |= (lease_type & SMB2_LEASE_WRITE) ?
+		SHARE_MODE_LEASE_WRITE : 0;
+	flags |= (lease_type & SMB2_LEASE_HANDLE) ?
+		SHARE_MODE_LEASE_HANDLE : 0;
+
+	if (d->flags == flags) {
+		return;
+	}
+
+	if (modified != NULL) {
+		*modified = true;
+	}
+	d->flags = flags;
+	d->modified = true;
+}
+
+struct share_mode_watch_state {
+	bool blockerdead;
+	struct server_id blocker;
+};
+
+static void share_mode_watch_done(struct tevent_req *subreq);
+
+struct tevent_req *share_mode_watch_send(
+	TALLOC_CTX *mem_ctx,
+	struct tevent_context *ev,
+	struct share_mode_lock *lck,
+	struct server_id blocker)
+{
+	TDB_DATA key = locking_key(&lck->data->id);
+	struct tevent_req *req = NULL, *subreq = NULL;
+	struct share_mode_watch_state *state = NULL;
+
+	req = tevent_req_create(
+		mem_ctx, &state, struct share_mode_watch_state);
+	if (req == NULL) {
+		return NULL;
+	}
+
+	subreq = g_lock_watch_data_send(state, ev, lock_ctx, key, blocker);
+	if (tevent_req_nomem(subreq, req)) {
+		return tevent_req_post(req, ev);
+	}
+	tevent_req_set_callback(subreq, share_mode_watch_done, req);
+	return req;
+}
+
+static void share_mode_watch_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(
+		subreq, struct tevent_req);
+	struct share_mode_watch_state *state = tevent_req_data(
+		req, struct share_mode_watch_state);
+	NTSTATUS status;
+
+	status = g_lock_watch_data_recv(
+		subreq, &state->blockerdead, &state->blocker);
+	if (tevent_req_nterror(req, status)) {
+		return;
+	}
+	tevent_req_done(req);
+}
+
+NTSTATUS share_mode_watch_recv(
+	struct tevent_req *req, bool *blockerdead, struct server_id *blocker)
+{
+	struct share_mode_watch_state *state = tevent_req_data(
+		req, struct share_mode_watch_state);
+	NTSTATUS status;
+
+	if (tevent_req_is_nterror(req, &status)) {
+		return status;
+	}
+	if (blockerdead != NULL) {
+		*blockerdead = state->blockerdead;
+	}
+	if (blocker != NULL) {
+		*blocker = state->blocker;
+	}
+	return NT_STATUS_OK;
+}
+
+struct fetch_share_mode_unlocked_state {
+	TALLOC_CTX *mem_ctx;
+	struct file_id id;
+	struct share_mode_lock *lck;
+};
+
+static void fetch_share_mode_unlocked_parser(
+	struct server_id exclusive,
+	size_t num_shared,
+	const struct server_id *shared,
+	const uint8_t *data,
+	size_t datalen,
+	void *private_data)
+{
+	struct fetch_share_mode_unlocked_state *state = private_data;
+	struct locking_tdb_data ltdb = { 0 };
+
+	if (datalen != 0) {
+		bool ok = locking_tdb_data_get(&ltdb, data, datalen);
+		if (!ok) {
+			DBG_DEBUG("locking_tdb_data_get failed\n");
+			return;
+		}
+	}
+
+	if (ltdb.share_mode_data_len == 0) {
+		/* Likely a ctdb tombstone record, ignore it */
+		return;
+	}
+
+	state->lck = talloc(state->mem_ctx, struct share_mode_lock);
+	if (state->lck == NULL) {
+		DEBUG(0, ("talloc failed\n"));
+		return;
+	}
+
+	state->lck->data = parse_share_modes(
+		state->lck,
+		state->id,
+		ltdb.share_mode_data_buf,
+		ltdb.share_mode_data_len);
+	if (state->lck->data == NULL) {
+		DBG_DEBUG("parse_share_modes failed\n");
+		TALLOC_FREE(state->lck);
+	}
+}
+
+/*******************************************************************
+ Get a share_mode_lock without locking the database or reference
+ counting. Used by smbstatus to display existing share modes.
+********************************************************************/
+
+struct share_mode_lock *fetch_share_mode_unlocked(TALLOC_CTX *mem_ctx,
+						  struct file_id id)
+{
+	struct fetch_share_mode_unlocked_state state = {
+		.mem_ctx = mem_ctx,
+		.id = id,
+	};
+	TDB_DATA key = locking_key(&id);
+	NTSTATUS status;
+
+	status = g_lock_dump(
+		lock_ctx, key, fetch_share_mode_unlocked_parser, &state);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("g_lock_dump failed: %s\n", nt_errstr(status));
+		return NULL;
+	}
+	return state.lck;
+}
+
+struct fetch_share_mode_state {
+	struct file_id id;
+	struct share_mode_lock *lck;
+	NTSTATUS status;
+};
+
+static void fetch_share_mode_fn(
+	struct server_id exclusive,
+	size_t num_shared,
+	const struct server_id *shared,
+	const uint8_t *data,
+	size_t datalen,
+	void *private_data);
+static void fetch_share_mode_done(struct tevent_req *subreq);
+
+/**
+ * @brief Get a share_mode_lock without locking or refcounting
+ *
+ * This can be used in a clustered Samba environment where the async dbwrap
+ * request is sent over a socket to the local ctdbd. If the send queue is full
+ * and the caller was issuing multiple async dbwrap requests in a loop, the
+ * caller knows it's probably time to stop sending requests for now and try
+ * again later.
+ *
+ * @param[in]  mem_ctx The talloc memory context to use.
+ *
+ * @param[in]  ev      The event context to work on.
+ *
+ * @param[in]  id      The file id for the locking.tdb key
+ *
+ * @param[out] queued  This boolean out parameter tells the caller whether the
+ *                     async request is blocked in a full send queue:
+ *
+ *                     false := request is dispatched
+ *
+ *                     true  := send queue is full, request waiting to be
+ *                              dispatched
+ *
+ * @return             The new async request, NULL on error.
+ **/
+struct tevent_req *fetch_share_mode_send(TALLOC_CTX *mem_ctx,
+					 struct tevent_context *ev,
+					 struct file_id id,
+					 bool *queued)
+{
+	struct tevent_req *req = NULL, *subreq = NULL;
+	struct fetch_share_mode_state *state = NULL;
+
+	*queued = false;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct fetch_share_mode_state);
+	if (req == NULL) {
+		return NULL;
+	}
+	state->id = id;
+
+	subreq = g_lock_dump_send(
+		state,
+		ev,
+		lock_ctx,
+		locking_key(&id),
+		fetch_share_mode_fn,
+		state);
+	if (tevent_req_nomem(subreq, req)) {
+		return tevent_req_post(req, ev);
+	}
+	tevent_req_set_callback(subreq, fetch_share_mode_done, req);
+	return req;
+}
+
+static void fetch_share_mode_fn(
+	struct server_id exclusive,
+	size_t num_shared,
+	const struct server_id *shared,
+	const uint8_t *data,
+	size_t datalen,
+	void *private_data)
+{
+	struct fetch_share_mode_state *state = talloc_get_type_abort(
+		private_data, struct fetch_share_mode_state);
+	struct locking_tdb_data ltdb = { 0 };
+
+	if (datalen != 0) {
+		bool ok = locking_tdb_data_get(&ltdb, data, datalen);
+		if (!ok) {
+			DBG_DEBUG("locking_tdb_data_get failed\n");
+			return;
+		}
+	}
+
+	if (ltdb.share_mode_data_len == 0) {
+		/* Likely a ctdb tombstone record, ignore it */
+		return;
+	}
+
+	state->lck = talloc(state, struct share_mode_lock);
+	if (state->lck == NULL) {
+		DBG_WARNING("talloc failed\n");
+		state->status = NT_STATUS_NO_MEMORY;
+		return;
+	}
+
+	state->lck->data = parse_share_modes(
+		state->lck,
+		state->id,
+		ltdb.share_mode_data_buf,
+		ltdb.share_mode_data_len);
+	if (state->lck->data == NULL) {
+		DBG_DEBUG("parse_share_modes failed\n");
+		state->status = NT_STATUS_INTERNAL_DB_CORRUPTION;
+		TALLOC_FREE(state->lck);
+		return;
+	}
+}
+
+static void fetch_share_mode_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(
+		subreq, struct tevent_req);
+	struct fetch_share_mode_state *state = tevent_req_data(
+		req, struct fetch_share_mode_state);
+	NTSTATUS status;
+
+	status = g_lock_dump_recv(subreq);
+	TALLOC_FREE(subreq);
+	if (tevent_req_nterror(req, status)) {
+		return;
+	}
+	if (tevent_req_nterror(req, state->status)) {
+		return;
+	}
+	tevent_req_done(req);
+}
+
+NTSTATUS fetch_share_mode_recv(struct tevent_req *req,
+			       TALLOC_CTX *mem_ctx,
+			       struct share_mode_lock **_lck)
+{
+	struct fetch_share_mode_state *state = tevent_req_data(
+		req, struct fetch_share_mode_state);
+	struct share_mode_lock *lck = NULL;
+
+	NTSTATUS status;
+
+	if (tevent_req_is_nterror(req, &status)) {
+		tevent_req_received(req);
+		return status;
+	}
+
+	if (state->lck == NULL) {
+		tevent_req_received(req);
+		return NT_STATUS_NOT_FOUND;
+	}
+
+	lck = talloc_move(mem_ctx, &state->lck);
+
+	if (DEBUGLEVEL >= 10) {
+		DBG_DEBUG("share_mode_data:\n");
+		NDR_PRINT_DEBUG(share_mode_data, lck->data);
+	}
+
+	*_lck = lck;
+	tevent_req_received(req);
+	return NT_STATUS_OK;
+}
+
+struct share_mode_forall_state {
+	TDB_DATA key;
+	int (*fn)(struct file_id fid,
+		  const struct share_mode_data *data,
+		  void *private_data);
+	void *private_data;
+};
+
+static void share_mode_forall_dump_fn(
+	struct server_id exclusive,
+	size_t num_shared,
+	const struct server_id *shared,
+	const uint8_t *data,
+	size_t datalen,
+	void *private_data)
+{
+	struct share_mode_forall_state *state = private_data;
+	struct file_id fid;
+	struct locking_tdb_data ltdb = { 0 };
+	bool ok;
+	struct share_mode_data *d;
+
+	if (state->key.dsize != sizeof(fid)) {
+		DBG_DEBUG("Got invalid key length %zu\n", state->key.dsize);
+		return;
+	}
+	memcpy(&fid, state->key.dptr, sizeof(fid));
+
+	ok = locking_tdb_data_get(&ltdb, data, datalen);
+	if (!ok) {
+		DBG_DEBUG("locking_tdb_data_get() failed\n");
+		return;
+	}
+
+	d = parse_share_modes(
+		talloc_tos(),
+		fid,
+		ltdb.share_mode_data_buf,
+		ltdb.share_mode_data_len);
+	if (d == NULL) {
+		DBG_DEBUG("parse_share_modes() failed\n");
+		return;
+	}
+
+	state->fn(fid, d, state->private_data);
+	TALLOC_FREE(d);
+}
+
+static int share_mode_forall_fn(TDB_DATA key, void *private_data)
+{
+	struct share_mode_forall_state *state = private_data;
+	NTSTATUS status;
+
+	state->key = key;
+
+	status = g_lock_dump(
+		lock_ctx, key, share_mode_forall_dump_fn, private_data);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("g_lock_dump failed: %s\n",
+			  nt_errstr(status));
+	}
+	return 0;
+}
+
+int share_mode_forall(int (*fn)(struct file_id fid,
+				const struct share_mode_data *data,
+				void *private_data),
+		      void *private_data)
+{
+	struct share_mode_forall_state state = {
+		.fn = fn,
+		.private_data = private_data
+	};
+	int ret;
+
+	if (lock_ctx == NULL) {
+		return 0;
+	}
+
+	ret = g_lock_locks(
+		lock_ctx, share_mode_forall_fn, &state);
+	if (ret < 0) {
+		DBG_DEBUG("g_lock_locks failed\n");
+	}
+	return ret;
+}
+
+struct share_entry_forall_state {
+	struct file_id fid;
+	const struct share_mode_data *data;
+	int (*fn)(struct file_id fid,
+		  const struct share_mode_data *data,
+		  const struct share_mode_entry *entry,
+		  void *private_data);
+	void *private_data;
+	int ret;
+};
+
+static bool share_entry_traverse_walker(
+	struct share_mode_entry *e,
+	bool *modified,
+	void *private_data)
+{
+	struct share_entry_forall_state *state = private_data;
+
+	state->ret = state->fn(
+		state->fid, state->data, e, state->private_data);
+	return (state->ret != 0);
+}
+
+static int share_entry_traverse_fn(struct file_id fid,
+				   const struct share_mode_data *data,
+				   void *private_data)
+{
+	struct share_entry_forall_state *state = private_data;
+	struct share_mode_lock lck = {
+		.data = discard_const_p(struct share_mode_data, data)
+	};
+	bool ok;
+
+	state->fid = fid;
+	state->data = data;
+
+	ok = share_mode_forall_entries(
+		&lck, share_entry_traverse_walker, state);
+	if (!ok) {
+		DBG_DEBUG("share_mode_forall_entries failed\n");
+		return false;
+	}
+
+	return state->ret;
+}
+
+/*******************************************************************
+ Call the specified function on each entry under management by the
+ share mode system.
+********************************************************************/
+
+int share_entry_forall(int (*fn)(struct file_id fid,
+				 const struct share_mode_data *data,
+				 const struct share_mode_entry *entry,
+				 void *private_data),
+		      void *private_data)
+{
+	struct share_entry_forall_state state = {
+		.fn = fn, .private_data = private_data };
+
+	return share_mode_forall(share_entry_traverse_fn, &state);
+}
+
+static int share_mode_entry_cmp(
+	struct server_id pid1,
+	uint64_t share_file_id1,
+	struct server_id pid2,
+	uint64_t share_file_id2)
+{
+	int cmp;
+
+	cmp = server_id_cmp(&pid1, &pid2);
+	if (cmp != 0) {
+		return cmp;
+	}
+	if (share_file_id1 != share_file_id2) {
+		return (share_file_id1 < share_file_id2) ? -1 : 1;
+	}
+	return 0;
+}
+
+static size_t share_mode_entry_find(
+	const uint8_t *data,
+	size_t num_share_modes,
+	struct server_id pid,
+	uint64_t share_file_id,
+	struct share_mode_entry *e,
+	bool *match)
+{
+	ssize_t left, right, middle;
+
+	*match = false;
+
+	if (num_share_modes == 0) {
+		return 0;
+	}
+
+	left = 0;
+	right = (num_share_modes-1);
+
+	while (left <= right) {
+		const uint8_t *middle_ptr = NULL;
+		int cmp;
+		bool ok;
+
+		middle = left + ((right - left) / 2);
+		middle_ptr = data + middle * SHARE_MODE_ENTRY_SIZE;
+
+		DBG_DEBUG("left=%zu, right=%zu, middle=%zu, middle_ptr=%p\n",
+			  left,
+			  right,
+			  middle,
+			  middle_ptr);
+
+		ok = share_mode_entry_get(middle_ptr, e);
+		if (!ok) {
+			DBG_DEBUG("share_mode_entry_get failed\n");
+			return 0;
+		}
+
+		cmp = share_mode_entry_cmp(
+			e->pid, e->share_file_id, pid, share_file_id);
+		if (cmp == 0) {
+			*match = true;
+			return middle;
+		}
+
+		if (cmp < 0) {
+			right = middle-1;
+		} else {
+			left = middle+1;
+		}
+	}
+
+	return left;
+}
+
+bool set_share_mode(struct share_mode_lock *lck,
+		    struct files_struct *fsp,
+		    uid_t uid,
+		    uint64_t mid,
+		    uint16_t op_type,
+		    const struct smb2_lease_key *lease_key,
+		    uint32_t share_access,
+		    uint32_t access_mask)
+{
+	struct share_mode_data *d = lck->data;
+	TDB_DATA key = locking_key(&d->id);
+	struct server_id my_pid = messaging_server_id(
+		fsp->conn->sconn->msg_ctx);
+	struct locking_tdb_data *ltdb = NULL;
+	size_t idx;
+	struct share_mode_entry e = { .pid.pid = 0 };
+	struct share_mode_entry_buf e_buf;
+	NTSTATUS status;
+	bool ok, found;
+
+	TDB_DATA dbufs[3];
+	size_t num_dbufs = 0;
+
+	status = locking_tdb_data_fetch(key, talloc_tos(), &ltdb);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("locking_tdb_data_fetch failed: %s\n",
+			  nt_errstr(status));
+		return false;
+	}
+	DBG_DEBUG("num_share_modes=%zu\n", ltdb->num_share_entries);
+
+	idx = share_mode_entry_find(
+		ltdb->share_entries,
+		ltdb->num_share_entries,
+		my_pid,
+		fh_get_gen_id(fsp->fh),
+		&e,
+		&found);
+	if (found) {
+		DBG_WARNING("Found duplicate share mode\n");
+		status = NT_STATUS_INTERNAL_DB_CORRUPTION;
+		goto done;
+	}
+
+	e = (struct share_mode_entry) {
+		.pid = my_pid,
+		.share_access = share_access,
+		.private_options = fh_get_private_options(fsp->fh),
+		.access_mask = access_mask,
+		.op_mid = mid,
+		.op_type = op_type,
+		.time.tv_sec = fsp->open_time.tv_sec,
+		.time.tv_usec = fsp->open_time.tv_usec,
+		.share_file_id = fh_get_gen_id(fsp->fh),
+		.uid = (uint32_t)uid,
+		.flags = (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) ?
+			SHARE_MODE_FLAG_POSIX_OPEN : 0,
+		.name_hash = fsp->name_hash,
+	};
+
+	if (op_type == LEASE_OPLOCK) {
+		const struct GUID *client_guid = fsp_client_guid(fsp);
+		e.client_guid = *client_guid;
+		e.lease_key = *lease_key;
+	}
+
+	ok = share_mode_entry_put(&e, &e_buf);
+	if (!ok) {
+		DBG_DEBUG("share_mode_entry_put failed\n");
+		status = NT_STATUS_INTERNAL_ERROR;
+		goto done;
+	}
+
+	DBG_DEBUG("idx=%zu, found=%d\n", idx, (int)found);
+
+	if (idx > 0) {
+		dbufs[num_dbufs] = (TDB_DATA) {
+			.dptr = discard_const_p(uint8_t, ltdb->share_entries),
+			.dsize = idx * SHARE_MODE_ENTRY_SIZE,
+		};
+		num_dbufs += 1;
+	}
+
+	dbufs[num_dbufs] = (TDB_DATA) {
+		.dptr = e_buf.buf, .dsize = SHARE_MODE_ENTRY_SIZE,
+	};
+	num_dbufs += 1;
+
+	if (idx < ltdb->num_share_entries) {
+		size_t num_after_idx = (ltdb->num_share_entries-idx);
+		dbufs[num_dbufs] = (TDB_DATA) {
+			.dptr = discard_const_p(uint8_t, ltdb->share_entries) +
+				idx * SHARE_MODE_ENTRY_SIZE,
+			.dsize = num_after_idx * SHARE_MODE_ENTRY_SIZE,
+		};
+		num_dbufs += 1;
+	}
+
+	{
+		size_t i;
+		for (i=0; i<num_dbufs; i++) {
+			DBG_DEBUG("dbufs[%zu]=(%p, %zu)\n",
+				  i,
+				  dbufs[i].dptr,
+				  dbufs[i].dsize);
+		}
+	}
+
+	if (num_dbufs == 1) {
+		/*
+		 * Storing a fresh record with just one share entry
+		 */
+		d->modified = true;
+	}
+
+	/*
+	 * If there was any existing data in
+	 * ltdb->share_entries, it's now been
+	 * moved and we've split it into:
+	 *
+	 * num_dbufs = 3
+	 * dbufs[0] -> old sorted data less than new_entry
+	 * dbufs[1] -> new_share_mode_entry
+	 * dbufs[2] -> old sorted_data greater than new entry.
+	 *
+	 * So the old data inside ltdb->share_entries is
+	 * no longer valid.
+	 *
+	 * If we're storing a brand new entry the
+	 * dbufs look like:
+	 *
+	 * num_dbufs = 1
+	 * dbufs[0] -> new_share_mode_entry
+	 *
+	 * Either way we must set ltdb->share_entries = NULL
+	 * and ltdb->num_share_entries = 0 so that
+	 * locking_tdb_data_store() doesn't use it to
+	 * store any data. It's no longer there.
+	 */
+
+	ltdb->share_entries = NULL;
+	ltdb->num_share_entries = 0;
+
+	status = locking_tdb_data_store(key, ltdb, dbufs, num_dbufs);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("locking_tdb_data_store failed: %s\n",
+			  nt_errstr(status));
+	}
+done:
+	TALLOC_FREE(ltdb);
+	return NT_STATUS_IS_OK(status);
+}
+
+static bool share_mode_for_one_entry(
+	bool (*fn)(struct share_mode_entry *e,
+		   bool *modified,
+		   void *private_data),
+	void *private_data,
+	size_t *i,
+	uint8_t *data,
+	size_t *num_share_modes,
+	bool *writeback)
+{
+	DATA_BLOB blob = {
+		.data = data + (*i) * SHARE_MODE_ENTRY_SIZE,
+		.length = SHARE_MODE_ENTRY_SIZE,
+	};
+	struct share_mode_entry e = {.pid.pid=0};
+	enum ndr_err_code ndr_err = NDR_ERR_SUCCESS;
+	bool modified = false;
+	bool stop = false;
+	struct server_id e_pid;
+	uint64_t e_share_file_id;
+
+	ndr_err = ndr_pull_struct_blob_all_noalloc(
+		&blob,
+		&e,
+		(ndr_pull_flags_fn_t)ndr_pull_share_mode_entry);
+	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+		DBG_WARNING("ndr_pull_share_mode_entry failed\n");
+		*i += 1;
+		return false;
+	}
+	if (DEBUGLEVEL >= 10) {
+		DBG_DEBUG("entry[%zu]:\n", *i);
+		NDR_PRINT_DEBUG(share_mode_entry, &e);
+	}
+
+	e_pid = e.pid;
+	e_share_file_id = e.share_file_id;
+
+	stop = fn(&e, &modified, private_data);
+
+	DBG_DEBUG("entry[%zu]: modified=%d, e.stale=%d\n",
+		  *i,
+		  (int)modified,
+		  (int)e.stale);
+
+	if (e.stale) {
+		if (DEBUGLEVEL>=10) {
+			DBG_DEBUG("share_mode_entry:\n");
+			NDR_PRINT_DEBUG(share_mode_entry, &e);
+		}
+
+		if (*i < *num_share_modes) {
+			memmove(blob.data,
+				blob.data + SHARE_MODE_ENTRY_SIZE,
+				(*num_share_modes - *i - 1) *
+				SHARE_MODE_ENTRY_SIZE);
+		}
+		*num_share_modes -= 1;
+		*writeback = true;
+		return stop;
+	}
+
+	if (modified) {
+		if (DEBUGLEVEL>=10) {
+			DBG_DEBUG("share_mode_entry:\n");
+			NDR_PRINT_DEBUG(share_mode_entry, &e);
+		}
+
+		/*
+		 * Make sure sorting order is kept intact
+		 */
+		SMB_ASSERT(server_id_equal(&e_pid, &e.pid));
+		SMB_ASSERT(e_share_file_id == e.share_file_id);
+
+		ndr_err = ndr_push_struct_into_fixed_blob(
+			&blob,
+			&e,
+			(ndr_push_flags_fn_t)
+			ndr_push_share_mode_entry);
+		if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+			DBG_WARNING("ndr_push_share_mode_entry "
+				    "failed: %s\n",
+				    ndr_errstr(ndr_err));
+			/*
+			 * Not much we can do, just ignore it
+			 */
+		}
+		*i += 1;
+		*writeback = true;
+		return stop;
+	}
+
+	if (stop) {
+		return true;
+	}
+
+	*i += 1;
+	return false;
+}
+
+bool share_mode_forall_entries(
+	struct share_mode_lock *lck,
+	bool (*fn)(struct share_mode_entry *e,
+		   bool *modified,
+		   void *private_data),
+	void *private_data)
+{
+	struct share_mode_data *d = lck->data;
+	TDB_DATA key = locking_key(&d->id);
+	struct locking_tdb_data *ltdb = NULL;
+	uint8_t *share_entries = NULL;
+	size_t num_share_entries;
+	bool writeback = false;
+	NTSTATUS status;
+	bool stop = false;
+	size_t i;
+
+	status = locking_tdb_data_fetch(key, talloc_tos(), &ltdb);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("locking_tdb_data_fetch failed: %s\n",
+			  nt_errstr(status));
+		return false;
+	}
+	DBG_DEBUG("num_share_modes=%zu\n", ltdb->num_share_entries);
+
+	num_share_entries = ltdb->num_share_entries;
+	share_entries = discard_const_p(uint8_t, ltdb->share_entries);
+
+	i = 0;
+	while (i<num_share_entries) {
+		stop = share_mode_for_one_entry(
+			fn,
+			private_data,
+			&i,
+			share_entries,
+			&num_share_entries,
+			&writeback);
+		if (stop) {
+			break;
+		}
+	}
+
+	DBG_DEBUG("num_share_entries=%zu, writeback=%d\n",
+		  num_share_entries,
+		  (int)writeback);
+
+	if (!writeback) {
+		return true;
+	}
+
+	if ((ltdb->num_share_entries != 0 ) && (num_share_entries == 0)) {
+		/*
+		 * This routine wiped all share entries, let
+		 * share_mode_data_store() delete the record
+		 */
+		d->modified = true;
+	}
+
+	ltdb->num_share_entries = num_share_entries;
+	ltdb->share_entries = share_entries;
+
+	status = locking_tdb_data_store(key, ltdb, NULL, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("locking_tdb_data_store failed: %s\n",
+			  nt_errstr(status));
+		return false;
+	}
+
+	return true;
+}
+
+struct share_mode_count_entries_state {
+	size_t num_share_modes;
+	NTSTATUS status;
+};
+
+static void share_mode_count_entries_fn(
+	struct server_id exclusive,
+	size_t num_shared,
+	const struct server_id *shared,
+	const uint8_t *data,
+	size_t datalen,
+	void *private_data)
+{
+	struct share_mode_count_entries_state *state = private_data;
+	struct locking_tdb_data ltdb = { 0 };
+	bool ok;
+
+	ok = locking_tdb_data_get(&ltdb, data, datalen);
+	if (!ok) {
+		DBG_WARNING("locking_tdb_data_get failed for %zu\n", datalen);
+		state->status = NT_STATUS_INTERNAL_DB_CORRUPTION;
+		return;
+	}
+	state->num_share_modes = ltdb.num_share_entries;
+	state->status = NT_STATUS_OK;
+}
+
+NTSTATUS share_mode_count_entries(struct file_id fid, size_t *num_share_modes)
+{
+	struct share_mode_count_entries_state state = {
+		.status = NT_STATUS_NOT_FOUND,
+	};
+	NTSTATUS status;
+
+	status = g_lock_dump(
+		lock_ctx,
+		locking_key(&fid),
+		share_mode_count_entries_fn,
+		&state);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("g_lock_dump failed: %s\n",
+			  nt_errstr(status));
+		return status;
+	}
+	if (!NT_STATUS_IS_OK(state.status)) {
+		DBG_DEBUG("share_mode_count_entries_fn failed: %s\n",
+			  nt_errstr(state.status));
+		return state.status;
+	}
+
+	*num_share_modes = state.num_share_modes;
+	return NT_STATUS_OK;
+}
+
+static bool share_mode_entry_do(
+	struct share_mode_lock *lck,
+	struct server_id pid,
+	uint64_t share_file_id,
+	void (*fn)(struct share_mode_entry *e,
+		   size_t num_share_modes,
+		   bool *modified,
+		   void *private_data),
+	void *private_data)
+{
+	struct share_mode_data *d = lck->data;
+	TDB_DATA key = locking_key(&d->id);
+	struct locking_tdb_data *ltdb = NULL;
+	size_t idx;
+	bool found = false;
+	bool modified = false;
+	struct share_mode_entry e;
+	uint8_t *e_ptr = NULL;
+	NTSTATUS status;
+	bool ret = false;
+
+	status = locking_tdb_data_fetch(key, talloc_tos(), &ltdb);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("locking_tdb_data_fetch failed: %s\n",
+			  nt_errstr(status));
+		return false;
+	}
+	DBG_DEBUG("num_share_modes=%zu\n", ltdb->num_share_entries);
+
+	idx = share_mode_entry_find(
+		ltdb->share_entries,
+		ltdb->num_share_entries,
+		pid,
+		share_file_id,
+		&e,
+		&found);
+	if (!found) {
+		DBG_WARNING("Did not find share mode entry for %"PRIu64"\n",
+			    share_file_id);
+		goto done;
+	}
+
+	if (DEBUGLEVEL>=10) {
+		DBG_DEBUG("entry[%zu]:\n", idx);
+		NDR_PRINT_DEBUG(share_mode_entry, &e);
+	}
+
+	fn(&e, ltdb->num_share_entries, &modified, private_data);
+
+	DBG_DEBUG("entry[%zu]: modified=%d, e.stale=%d\n",
+		  idx,
+		  (int)modified,
+		  (int)e.stale);
+
+	if (!e.stale && !modified) {
+		ret = true;
+		goto done;
+	}
+
+	e_ptr = discard_const_p(uint8_t, ltdb->share_entries) +
+		idx * SHARE_MODE_ENTRY_SIZE;
+
+	if (e.stale) {
+		/*
+		 * Move the rest down one entry
+		 */
+		size_t behind = ltdb->num_share_entries - idx - 1;
+		if (behind != 0) {
+			memmove(e_ptr,
+				e_ptr + SHARE_MODE_ENTRY_SIZE,
+				behind * SHARE_MODE_ENTRY_SIZE);
+		}
+		ltdb->num_share_entries -= 1;
+
+		if (ltdb->num_share_entries == 0) {
+			/*
+			 * Tell share_mode_lock_destructor() to delete
+			 * the whole record
+			 */
+			d->modified = true;
+		}
+
+		if (DEBUGLEVEL>=10) {
+			DBG_DEBUG("share_mode_entry:\n");
+			NDR_PRINT_DEBUG(share_mode_entry, &e);
+		}
+	} else {
+		struct share_mode_entry_buf buf;
+		bool ok;
+
+		if (ltdb->num_share_entries != 1) {
+			/*
+			 * Make sure the sorting order stays intact
+			 */
+			SMB_ASSERT(server_id_equal(&e.pid, &pid));
+			SMB_ASSERT(e.share_file_id == share_file_id);
+		}
+
+		ok = share_mode_entry_put(&e, &buf);
+		if (!ok) {
+			DBG_DEBUG("share_mode_entry_put failed\n");
+			goto done;
+		}
+		memcpy(e_ptr, buf.buf, SHARE_MODE_ENTRY_SIZE);
+	}
+
+	status = locking_tdb_data_store(key, ltdb, NULL, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("locking_tdb_data_store failed: %s\n",
+			  nt_errstr(status));
+		goto done;
+	}
+
+	ret = true;
+done:
+	TALLOC_FREE(ltdb);
+	return ret;
+}
+
+struct del_share_mode_state {
+	bool ok;
+};
+
+static void del_share_mode_fn(
+	struct share_mode_entry *e,
+	size_t num_share_modes,
+	bool *modified,
+	void *private_data)
+{
+	struct del_share_mode_state *state = private_data;
+	e->stale = true;
+	state->ok = true;
+}
+
+bool del_share_mode(struct share_mode_lock *lck, files_struct *fsp)
+{
+	struct del_share_mode_state state = { .ok = false };
+	bool ok;
+
+	ok = share_mode_entry_do(
+		lck,
+		messaging_server_id(fsp->conn->sconn->msg_ctx),
+		fh_get_gen_id(fsp->fh),
+		del_share_mode_fn,
+		&state);
+	if (!ok) {
+		DBG_DEBUG("share_mode_entry_do failed\n");
+		return false;
+	}
+	if (!state.ok) {
+		DBG_DEBUG("del_share_mode_fn failed\n");
+		return false;
+	}
+	return true;
+}
+
+struct remove_share_oplock_state {
+	bool ok;
+};
+
+static void remove_share_oplock_fn(
+	struct share_mode_entry *e,
+	size_t num_share_modes,
+	bool *modified,
+	void *private_data)
+{
+	struct remove_share_oplock_state *state = private_data;
+
+	e->op_type = NO_OPLOCK;
+	*modified = true;
+	state->ok = true;
+}
+
+bool remove_share_oplock(struct share_mode_lock *lck, files_struct *fsp)
+{
+	struct remove_share_oplock_state state = { .ok = false };
+	bool ok;
+
+	ok = share_mode_entry_do(
+		lck,
+		messaging_server_id(fsp->conn->sconn->msg_ctx),
+		fh_get_gen_id(fsp->fh),
+		remove_share_oplock_fn,
+		&state);
+	if (!ok) {
+		DBG_DEBUG("share_mode_entry_do failed\n");
+		return false;
+	}
+	if (!state.ok) {
+		DBG_DEBUG("remove_share_oplock_fn failed\n");
+		return false;
+	}
+
+	if (fsp->oplock_type == LEASE_OPLOCK) {
+		remove_lease_if_stale(
+			lck,
+			fsp_client_guid(fsp),
+			&fsp->lease->lease.lease_key);
+	}
+
+	share_mode_wakeup_waiters(fsp->file_id);
+
+	return true;
+}
+
+struct downgrade_share_oplock_state {
+	bool ok;
+};
+
+static void downgrade_share_oplock_fn(
+	struct share_mode_entry *e,
+	size_t num_share_modes,
+	bool *modified,
+	void *private_data)
+{
+	struct downgrade_share_oplock_state *state = private_data;
+
+	e->op_type = LEVEL_II_OPLOCK;
+	*modified = true;
+	state->ok = true;
+}
+
+bool downgrade_share_oplock(struct share_mode_lock *lck, files_struct *fsp)
+{
+	struct downgrade_share_oplock_state state = { .ok = false };
+	bool ok;
+
+	ok = share_mode_entry_do(
+		lck,
+		messaging_server_id(fsp->conn->sconn->msg_ctx),
+		fh_get_gen_id(fsp->fh),
+		downgrade_share_oplock_fn,
+		&state);
+	if (!ok) {
+		DBG_DEBUG("share_mode_entry_do failed\n");
+		return false;
+	}
+	if (!state.ok) {
+		DBG_DEBUG("downgrade_share_oplock_fn failed\n");
+		return false;
+	}
+
+	lck->data->flags |= SHARE_MODE_LEASE_READ;
+	lck->data->modified = true;
+
+	return true;
+}
+
+bool mark_share_mode_disconnected(struct share_mode_lock *lck,
+				  struct files_struct *fsp)
+{
+	struct server_id disconnected_pid = { .pid = 0 };
+	bool ok;
+
+	if (fsp->op == NULL) {
+		return false;
+	}
+	if (!fsp->op->global->durable) {
+		return false;
+	}
+
+	server_id_set_disconnected(&disconnected_pid);
+
+	ok = reset_share_mode_entry(
+		lck,
+		messaging_server_id(fsp->conn->sconn->msg_ctx),
+		fh_get_gen_id(fsp->fh),
+		disconnected_pid,
+		UINT64_MAX,
+		fsp->op->global->open_persistent_id);
+
+	return ok;
+}
+
+bool reset_share_mode_entry(
+	struct share_mode_lock *lck,
+	struct server_id old_pid,
+	uint64_t old_share_file_id,
+	struct server_id new_pid,
+	uint64_t new_mid,
+	uint64_t new_share_file_id)
+{
+	struct share_mode_data *d = lck->data;
+	TDB_DATA key = locking_key(&d->id);
+	struct locking_tdb_data *ltdb = NULL;
+	struct share_mode_entry e;
+	struct share_mode_entry_buf e_buf;
+	NTSTATUS status;
+	bool ret = false;
+	bool ok;
+
+	status = locking_tdb_data_fetch(key, talloc_tos(), &ltdb);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("locking_tdb_data_fetch failed: %s\n",
+			  nt_errstr(status));
+		return false;
+	}
+
+	if (ltdb->num_share_entries != 1) {
+		DBG_DEBUG("num_share_modes=%zu\n", ltdb->num_share_entries);
+		goto done;
+	}
+
+	ok = share_mode_entry_get(ltdb->share_entries, &e);
+	if (!ok) {
+		DBG_WARNING("share_mode_entry_get failed\n");
+		goto done;
+	}
+
+	ret = share_mode_entry_cmp(
+		old_pid, old_share_file_id, e.pid, e.share_file_id);
+	if (ret != 0) {
+		struct server_id_buf tmp1, tmp2;
+		DBG_WARNING("Expected pid=%s, file_id=%"PRIu64", "
+			    "got pid=%s, file_id=%"PRIu64"\n",
+			    server_id_str_buf(old_pid, &tmp1),
+			    old_share_file_id,
+			    server_id_str_buf(e.pid, &tmp2),
+			    e.share_file_id);
+		goto done;
+	}
+
+	e.pid = new_pid;
+	if (new_mid != UINT64_MAX) {
+		e.op_mid = new_mid;
+	}
+	e.share_file_id = new_share_file_id;
+
+	ok = share_mode_entry_put(&e, &e_buf);
+	if (!ok) {
+		DBG_WARNING("share_mode_entry_put failed\n");
+		goto done;
+	}
+
+	ltdb->share_entries = e_buf.buf;
+
+	status = locking_tdb_data_store(key, ltdb, NULL, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_DEBUG("locking_tdb_data_store failed: %s\n",
+			  nt_errstr(status));
+		goto done;
+	}
+
+	d->modified = true;
+	ret = true;
+done:
+	TALLOC_FREE(ltdb);
+	return true;
+}