3 files changed, 64 insertions, 1 deletions

diff --git a/lib/private/files/cache/cache.php b/lib/private/files/cache/cache.php
index f3e22701f40..231dbe37695 100644
--- a/lib/private/files/cache/cache.php
+++ b/lib/private/files/cache/cache.php
@@ -313,6 +313,14 @@ class Cache {
 		$fields = array(
 			'path', 'parent', 'name', 'mimetype', 'size', 'mtime', 'storage_mtime', 'encrypted',
 			'etag', 'permissions');
+
+		$doNotCopyStorageMTime = false;
+		if (array_key_exists('mtime', $data) && $data['mtime'] === null) {
+			// this horrific magic tells it to not copy storage_mtime to mtime
+			unset($data['mtime']);
+			$doNotCopyStorageMTime = true;
+		}
+
 		$params = array();
 		$queryParts = array();
 		foreach ($data as $name => $value) {
@@ -325,7 +333,7 @@ class Cache {
 					$queryParts[] = '`mimepart`';
 					$value = $this->mimetypeLoader->getId($value);
 				} elseif ($name === 'storage_mtime') {
-					if (!isset($data['mtime'])) {
+					if (!$doNotCopyStorageMTime && !isset($data['mtime'])) {
 						$params[] = $value;
 						$queryParts[] = '`mtime`';
 					}
diff --git a/lib/private/files/cache/updater.php b/lib/private/files/cache/updater.php
index 2de0c8fe067..c82ee33a1b1 100644
--- a/lib/private/files/cache/updater.php
+++ b/lib/private/files/cache/updater.php
@@ -193,12 +193,26 @@ class Updater {
 			$targetCache->correctFolderSize($targetInternalPath);
 			$this->correctParentStorageMtime($sourceStorage, $sourceInternalPath);
 			$this->correctParentStorageMtime($targetStorage, $targetInternalPath);
+			$this->updateStorageMTimeOnly($targetStorage, $targetInternalPath);
 			$this->propagator->addChange($source);
 			$this->propagator->addChange($target);
 			$this->propagator->propagateChanges();
 		}
 	}
 
+	private function updateStorageMTimeOnly($storage, $internalPath) {
+		$cache = $storage->getCache();
+		$fileId = $cache->getId($internalPath);
+		if ($fileId !== -1) {
+			$cache->update(
+				$fileId, [
+					'mtime' => null, // this magic tells it to not overwrite mtime
+					'storage_mtime' => $storage->filemtime($internalPath)
+				]
+			);
+		}
+	}
+
 	/**
 	 * update the storage_mtime of the direct parent in the cache to the mtime from the storage
 	 *
diff --git a/tests/lib/files/cache/updater.php b/tests/lib/files/cache/updater.php
index e3fa26829b4..b7e76aeace4 100644
--- a/tests/lib/files/cache/updater.php
+++ b/tests/lib/files/cache/updater.php
@@ -161,6 +161,47 @@ class Updater extends \Test\TestCase {
 		$this->assertEquals($cached['fileid'], $cachedTarget['fileid']);
 	}
 
+	public function testUpdateStorageMTime() {
+		$this->storage->mkdir('sub');
+		$this->storage->mkdir('sub2');
+		$this->storage->file_put_contents('sub/foo.txt', 'qwerty');
+
+		$this->updater->update('sub');
+		$this->updater->update('sub/foo.txt');
+		$this->updater->update('sub2');
+
+		$cachedSourceParent = $this->cache->get('sub');
+		$cachedSource = $this->cache->get('sub/foo.txt');
+
+		$this->storage->rename('sub/foo.txt', 'sub2/bar.txt');
+
+		// simulate storage having a different mtime
+		$testmtime = 1433323578;
+
+		// source storage mtime change
+		$this->storage->touch('sub', $testmtime);
+
+		// target storage mtime change
+		$this->storage->touch('sub2', $testmtime);
+		// some storages (like Dropbox) change storage mtime on rename
+		$this->storage->touch('sub2/bar.txt', $testmtime);
+
+		$this->updater->rename('sub/foo.txt', 'sub2/bar.txt');
+
+		$cachedTargetParent = $this->cache->get('sub2');
+		$cachedTarget = $this->cache->get('sub2/bar.txt');
+
+		$this->assertEquals($cachedSource['mtime'], $cachedTarget['mtime'], 'file mtime preserved');
+
+		$this->assertNotEquals($cachedTarget['storage_mtime'], $cachedTarget['mtime'], 'mtime is not storage_mtime for moved file');
+
+		$this->assertEquals($testmtime, $cachedTarget['storage_mtime'], 'target file storage_mtime propagated');
+		$this->assertNotEquals($testmtime, $cachedTarget['mtime'], 'target file mtime changed, not from storage');
+
+		$this->assertEquals($testmtime, $cachedTargetParent['storage_mtime'], 'target parent storage_mtime propagated');
+		$this->assertNotEquals($testmtime, $cachedTargetParent['mtime'], 'target folder mtime changed, not from storage');
+	}
+
 	public function testNewFileDisabled() {
 		$this->storage->file_put_contents('foo.txt', 'bar');
 		$this->assertFalse($this->cache->inCache('foo.txt'));