The patch below does not apply to the 4.19-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 <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From e2c8e92d1140754073ad3799eb6620c76bab2078 Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@xxxxxxxx>
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().
Fixes: a315e68f6e8b30 ("Btrfs: fix invalid attempt to free reserved space on failure to cow range")
CC: stable@xxxxxxxxxxxxxxx # 4.14+
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 4583f0763571..1b6cd937f214 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -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);
