From 6684d94fcafeb905accf8b18e8e9c3f2060d9346 Mon Sep 17 00:00:00 2001
From: Niels Dossche <7771979+nielsdos@users.noreply.github.com>
Date: Thu, 9 Feb 2023 22:24:18 +0100
Subject: [PATCH] Fix GH-10548: copy() fails on cifs mounts because of
 incorrect length (cfr_max) specified in streams.c:1584 copy_file_range()

On some filesystems, the copy operation fails if we specify a size
larger than the file size in certain circumstances and configurations.
In those cases EIO will be returned as errno and we will therefore fall
back to other methods.
---
 main/streams/streams.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/main/streams/streams.c b/main/streams/streams.c
index de53e483c62b..4cd211ad85fe 100644
--- a/main/streams/streams.c
+++ b/main/streams/streams.c
@@ -1614,6 +1614,13 @@ PHPAPI zend_result _php_stream_copy_to_stream_ex(php_stream *src, php_stream *de
 						/* not implemented by this Linux kernel */
 						break;
 
+					case EIO:
+						/* Some filesystems will cause failures if the max length is greater than the file length
+						 * in certain circumstances and configuration. In those cases the errno is EIO and we will
+						 * fall back to other methods. We cannot use stat to determine the file length upfront because
+						 * that is prone to races and outdated caching. */
+						break;
+
 					default:
 						/* unexpected I/O error - give up, no fallback */
 						*len = haveread;