FAILED: patch "[PATCH] btrfs: fix wrong file range cleanup after an error filling" failed to apply to 4.14-stable tree

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e2c8e92d1140754073ad3799eb6620c76bab2078 Mon Sep 17 00:00:00 2001
From: Filipe Manana <[email protected]>
Date: Wed, 27 May 2020 11:15:53 +0100
Subject: [PATCH] btrfs: fix wrong file range cleanup after an error filling
dealloc range

If an error happens while running dellaloc in COW mode for a range, we can end up calling extent_clear_unlock_delalloc() for a range that goes beyond our range's end offset by 1 byte, which affects 1 extra page. This results in clearing bits and doing page operations (such as a page unlock) outside our target range.

Fix that by calling extent_clear_unlock_delalloc() with an inclusive end offset, instead of an exclusive end offset, at cow_file_range().

index 4583f0763571..1b6cd937f214 100644
@@ -1141,7 +1141,7 @@ static noinline int cow_file_range(struct inode *inode,
 	 */
 	if (extent_reserved) {
 		extent_clear_unlock_delalloc(inode, start,
-					     start + cur_alloc_size,
+					     start + cur_alloc_size - 1,
 					     locked_page,
 					     clear_bits,
 					     page_ops);