diff --git a/db_structure.xml b/db_structure.xml
index 6d1cf6973c552c39570c353a17dc739398c7579f..95acefcfaeec4931f5e7ed10b4da4b706c8fb4a5 100644
--- a/db_structure.xml
+++ b/db_structure.xml
@@ -1180,5 +1180,44 @@
</table>
+ <table>
+
+ <!--
+ Table for storing high-level locking
+ -->
+ <name>*dbprefix*locks</name>
+
+ <declaration>
+
+ <field>
+ <name>lock</name>
+ <type>integer</type>
+ <default>0</default>
+ <notnull>true</notnull>
+ <length>4</length>
+ </field>
+
+ <field>
+ <name>path</name>
+ <type>text</type>
+ <notnull>true</notnull>
+ <length>64</length>
+ </field>
+
+
+ <index>
+ <primary>true</primary>
+ <unique>true</unique>
+ <name>lock_path_index</name>
+ <field>
+ <name>path</name>
+ <sorting>ascending</sorting>
+ </field>
+ </index>
+
+ </declaration>
+
+ </table>
+
</database>
diff --git a/lib/private/lock/dblockingprovider.php b/lib/private/lock/dblockingprovider.php
new file mode 100644
index 0000000000000000000000000000000000000000..70f4539eb286cba571a80dd6c44ef796ce83d6d8
--- /dev/null
+++ b/lib/private/lock/dblockingprovider.php
@@ -0,0 +1,131 @@
+<?php
+/**
+ * @author Robin Appelman <icewind@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program. If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\Lock;
+
+use OCP\IDBConnection;
+use OCP\Lock\LockedException;
+
+class DBLockingProvider extends AbstractLockingProvider {
+ /**
+ * @var \OCP\IDBConnection
+ */
+ private $connection;
+
+ /**
+ * @param \OCP\IDBConnection $connection
+ */
+ public function __construct(IDBConnection $connection) {
+ $this->connection = $connection;
+ }
+
+ protected function initLockField($path) {
+ $this->connection->insertIfNotExist('*PREFIX*locks', ['path' => $path, 'lock' => 0], ['path']);
+ }
+
+ /**
+ * @param string $path
+ * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+ * @return bool
+ */
+ public function isLocked($path, $type) {
+ $query = $this->connection->prepare('SELECT `lock` from `*PREFIX*locks` WHERE `path` = ?');
+ $query->execute([$path]);
+ $lockValue = (int)$query->fetchColumn();
+ if ($type === self::LOCK_SHARED) {
+ return $lockValue > 0;
+ } else if ($type === self::LOCK_EXCLUSIVE) {
+ return $lockValue === -1;
+ } else {
+ return false;
+ }
+ }
+
+ /**
+ * @param string $path
+ * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+ * @throws \OCP\Lock\LockedException
+ */
+ public function acquireLock($path, $type) {
+ $this->initLockField($path);
+ if ($type === self::LOCK_SHARED) {
+ $result = $this->connection->executeUpdate(
+ 'UPDATE `*PREFIX*locks` SET `lock` = `lock` + 1 WHERE `path` = ? AND `lock` >= 0',
+ [$path]
+ );
+ } else {
+ $result = $this->connection->executeUpdate(
+ 'UPDATE `*PREFIX*locks` SET `lock` = -1 WHERE `path` = ? AND `lock` = 0',
+ [$path]
+ );
+ }
+ if ($result !== 1) {
+ throw new LockedException($path);
+ }
+ $this->markAcquire($path, $type);
+ }
+
+ /**
+ * @param string $path
+ * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+ */
+ public function releaseLock($path, $type) {
+ $this->initLockField($path);
+ if ($type === self::LOCK_SHARED) {
+ $this->connection->executeUpdate(
+ 'UPDATE `*PREFIX*locks` SET `lock` = `lock` - 1 WHERE `path` = ? AND `lock` > 0',
+ [$path]
+ );
+ } else {
+ $this->connection->executeUpdate(
+ 'UPDATE `*PREFIX*locks` SET `lock` = 0 WHERE `path` = ? AND `lock` = -1',
+ [$path]
+ );
+ }
+ $this->markRelease($path, $type);
+ }
+
+ /**
+ * Change the type of an existing lock
+ *
+ * @param string $path
+ * @param int $targetType self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+ * @throws \OCP\Lock\LockedException
+ */
+ public function changeLock($path, $targetType) {
+ $this->initLockField($path);
+ if ($targetType === self::LOCK_SHARED) {
+ $result = $this->connection->executeUpdate(
+ 'UPDATE `*PREFIX*locks` SET `lock` = 1 WHERE `path` = ? AND `lock` = -1',
+ [$path]
+ );
+ } else {
+ $result = $this->connection->executeUpdate(
+ 'UPDATE `*PREFIX*locks` SET `lock` = -1 WHERE `path` = ? AND `lock` = 1',
+ [$path]
+ );
+ }
+ if ($result !== 1) {
+ throw new LockedException($path);
+ }
+ $this->markChange($path, $targetType);
+ }
+}
diff --git a/lib/repair/dropoldtables.php b/lib/repair/dropoldtables.php
index cfe0df6cb5bd5dc908b278317289984f01b68976..89f872e16ccd130dae08f38b6875f0bf989c7405 100644
--- a/lib/repair/dropoldtables.php
+++ b/lib/repair/dropoldtables.php
@@ -76,7 +76,6 @@ class DropOldTables extends BasicEmitter implements RepairStep {
'calendar_share_event',
'foldersize',
'fscache',
- 'locks',
'log',
'media_albums',
'media_artists',
diff --git a/tests/lib/lock/dblockingprovider.php b/tests/lib/lock/dblockingprovider.php
new file mode 100644
index 0000000000000000000000000000000000000000..4229ffb9c516eefd144769bf6fcdbfe736e97948
--- /dev/null
+++ b/tests/lib/lock/dblockingprovider.php
@@ -0,0 +1,43 @@
+<?php
+/**
+ * @author Robin Appelman <icewind@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program. If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace Test\Lock;
+
+class DBLockingProvider extends LockingProvider {
+
+ /**
+ * @var \OCP\IDBConnection
+ */
+ private $connection;
+
+ /**
+ * @return \OCP\Lock\ILockingProvider
+ */
+ protected function getInstance() {
+ $this->connection = \OC::$server->getDatabaseConnection();
+ return new \OC\Lock\DBLockingProvider($this->connection);
+ }
+
+ public function tearDown() {
+ $this->connection->executeQuery('DELETE FROM `*PREFIX*locks`');
+ parent::tearDown();
+ }
+}
diff --git a/version.php b/version.php
index 7ccd2e6b54882ae0a9cb6cea87bc5fa390d6b3a8..a115f4b26be3c8d0392d9f2e4679b39476e8e4e6 100644
--- a/version.php
+++ b/version.php
@@ -22,7 +22,7 @@
// We only can count up. The 4. digit is only for the internal patchlevel to trigger DB upgrades
// between betas, final and RCs. This is _not_ the public version number. Reset minor/patchlevel
// when updating major/minor version number.
-$OC_Version=array(8, 2, 0, 3);
+$OC_Version=array(8, 2, 0, 4);
// The human readable string
$OC_VersionString='8.2 pre alpha';