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 stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e2c8e92d1140754073ad3799eb6620c76bab2078 Mon Sep 17 00:00:00 2001
From: Filipe Manana fdmanana@suse.com 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@vger.kernel.org # 4.14+ Signed-off-by: Filipe Manana fdmanana@suse.com Signed-off-by: David Sterba dsterba@suse.com
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);