5 files changed, 38 insertions, 3 deletions
diff --git a/lib/private/Files/ObjectStore/Azure.php b/lib/private/Files/ObjectStore/Azure.php
index 899c826ec19..e162c510b98 100644
--- a/lib/private/Files/ObjectStore/Azure.php
+++ b/lib/private/Files/ObjectStore/Azure.php
@@ -115,4 +115,17 @@ class Azure implements IObjectStore {
 	public function deleteObject($urn) {
 		$this->getBlobClient()->deleteBlob($this->containerName, $urn);
 	}
+
+	public function objectExists($urn) {
+		try {
+			$this->getBlobClient()->getBlobMetadata($this->containerName, $urn);
+			return true;
+		} catch (ServiceException $e) {
+			if ($e->getCode() === 404) {
+				return false;
+			} else {
+				throw $e;
+			}
+		}
+	}
 }
diff --git a/lib/private/Files/ObjectStore/ObjectStoreStorage.php b/lib/private/Files/ObjectStore/ObjectStoreStorage.php
index d8649129d90..12e47d76aa9 100644
--- a/lib/private/Files/ObjectStore/ObjectStoreStorage.php
+++ b/lib/private/Files/ObjectStore/ObjectStoreStorage.php
@@ -413,18 +413,30 @@ class ObjectStoreStorage extends \OC\Files\Storage\Common {
 		$stat['mimetype'] = $mimetype;
 		$stat['etag'] = $this->getETag($path);
 
-		$fileId = $this->getCache()->put($path, $stat);
+		$exists = $this->getCache()->inCache($path);
+		$uploadPath = $exists ? $path : $path . '.part';
+		$fileId = $this->getCache()->put($uploadPath, $stat);
+		$urn = $this->getURN($fileId);
 		try {
 			//upload to object storage
 			$this->objectStore->writeObject($this->getURN($fileId), fopen($tmpFile, 'r'));
 		} catch (\Exception $ex) {
-			$this->getCache()->remove($path);
+			$this->getCache()->remove($uploadPath);
 			$this->logger->logException($ex, [
 				'app' => 'objectstore',
-				'message' => 'Could not create object ' . $this->getURN($fileId) . ' for ' . $path,
+				'message' => 'Could not create object ' . $urn . ' for ' . $path,
 			]);
 			throw $ex; // make this bubble up
 		}
+
+		if (!$exists) {
+			if ($this->objectStore->objectExists($urn)) {
+				$this->getCache()->move($uploadPath, $path);
+			} else {
+				$this->getCache()->remove($uploadPath);
+				throw new \Exception("Object not found after writing (urn: $urn, path: $path)", 404);
+			}
+		}
 	}
 
 	/**
diff --git a/lib/private/Files/ObjectStore/S3ObjectTrait.php b/lib/private/Files/ObjectStore/S3ObjectTrait.php
index 280a8efa81c..a1110d87c8f 100644
--- a/lib/private/Files/ObjectStore/S3ObjectTrait.php
+++ b/lib/private/Files/ObjectStore/S3ObjectTrait.php
@@ -90,4 +90,8 @@ trait S3ObjectTrait {
 			'Key' => $urn
 		]);
 	}
+
+	public function objectExists($urn) {
+		return $this->getConnection()->doesObjectExist($this->bucket, $urn);
+	}
 }
diff --git a/lib/private/Files/ObjectStore/StorageObjectStore.php b/lib/private/Files/ObjectStore/StorageObjectStore.php
index 0d35ba2ed7a..f9fc1b5a4aa 100644
--- a/lib/private/Files/ObjectStore/StorageObjectStore.php
+++ b/lib/private/Files/ObjectStore/StorageObjectStore.php
@@ -89,4 +89,7 @@ class StorageObjectStore implements IObjectStore {
 		$this->storage->unlink($urn);
 	}
 
+	public function objectExists($urn) {
+		return $this->storage->file_exists($urn);
+	}
 }
diff --git a/lib/private/Files/ObjectStore/Swift.php b/lib/private/Files/ObjectStore/Swift.php
index 667b92bd1d6..39de41869a3 100644
--- a/lib/private/Files/ObjectStore/Swift.php
+++ b/lib/private/Files/ObjectStore/Swift.php
@@ -127,4 +127,7 @@ class Swift implements IObjectStore {
 		$this->getContainer()->delete();
 	}
 
+	public function objectExists($urn) {
+		return $this->getContainer()->objectExists($urn);
+	}
 }