From f909d2a39ad8c400a1e8bdef34dc3fd8b2ec6bd9 Mon Sep 17 00:00:00 2001
From: Roeland Jago Douma <roeland@famdouma.nl>
Date: Mon, 31 Aug 2020 12:25:20 +0200
Subject: [PATCH 1/2] Don't lose filecache entry on s3 overwrite error

If the object store errors we should not always delete the filecache
entry. As this might lead to people losing access to their files.

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>
---
 .../Files/ObjectStore/ObjectStoreStorage.php  | 21 ++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/lib/private/Files/ObjectStore/ObjectStoreStorage.php b/lib/private/Files/ObjectStore/ObjectStoreStorage.php
index e0d437839a066..1658c91391009 100644
--- a/lib/private/Files/ObjectStore/ObjectStoreStorage.php
+++ b/lib/private/Files/ObjectStore/ObjectStoreStorage.php
@@ -463,11 +463,22 @@ public function writeStream(string $path, $stream, int $size = null): int {
 				$this->objectStore->writeObject($urn, $stream);
 			}
 		} catch (\Exception $ex) {
-			$this->getCache()->remove($uploadPath);
-			$this->logger->logException($ex, [
-				'app' => 'objectstore',
-				'message' => 'Could not create object ' . $urn . ' for ' . $path,
-			]);
+			if (!$exists) {
+				/*
+				 * Only remove the entry if we are dealing with a new file.
+				 * Else people lose access to existing files
+				 */
+				$this->getCache()->remove($uploadPath);
+				$this->logger->logException($ex, [
+					'app' => 'objectstore',
+					'message' => 'Could not create object ' . $urn . ' for ' . $path,
+				]);
+			} else {
+				$this->logger->logException($ex, [
+					'app' => 'objectstore',
+					'message' => 'Could not update object ' . $urn . ' for ' . $path,
+				]);
+			}
 			throw $ex; // make this bubble up
 		}
 

From 55ce30ad53ce1998fee06a75b02351fea53c7c96 Mon Sep 17 00:00:00 2001
From: Roeland Jago Douma <roeland@famdouma.nl>
Date: Mon, 31 Aug 2020 12:28:04 +0200
Subject: [PATCH 2/2] Only update the filecache entry once the file has been
 written to S3

If we already update before we have no way to revert if the upload
fails.

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>
---
 .../Files/ObjectStore/ObjectStoreStorage.php        | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/lib/private/Files/ObjectStore/ObjectStoreStorage.php b/lib/private/Files/ObjectStore/ObjectStoreStorage.php
index 1658c91391009..bd5b2d4777085 100644
--- a/lib/private/Files/ObjectStore/ObjectStoreStorage.php
+++ b/lib/private/Files/ObjectStore/ObjectStoreStorage.php
@@ -444,7 +444,13 @@ public function writeStream(string $path, $stream, int $size = null): int {
 
 		$exists = $this->getCache()->inCache($path);
 		$uploadPath = $exists ? $path : $path . '.part';
-		$fileId = $this->getCache()->put($uploadPath, $stat);
+
+		if ($exists) {
+			$fileId = $stat['fileid'];
+		} else {
+			$fileId = $this->getCache()->put($uploadPath, $stat);
+		}
+
 		$urn = $this->getURN($fileId);
 		try {
 			//upload to object storage
@@ -459,6 +465,7 @@ public function writeStream(string $path, $stream, int $size = null): int {
 				if (is_resource($countStream)) {
 					fclose($countStream);
 				}
+				$stat['size'] = $size;
 			} else {
 				$this->objectStore->writeObject($urn, $stream);
 			}
@@ -482,7 +489,9 @@ public function writeStream(string $path, $stream, int $size = null): int {
 			throw $ex; // make this bubble up
 		}
 
-		if (!$exists) {
+		if ($exists) {
+			$this->getCache()->update($fileId, $stat);
+		} else {
 			if ($this->objectStore->objectExists($urn)) {
 				$this->getCache()->move($uploadPath, $path);
 			} else {