From: Robbie Ko <robbieko@synology.com>
Date: Mon, 20 Jul 2020 01:42:09 +0000 (+0800)
Subject: btrfs: fix page leaks after failure to lock page for delalloc
X-Git-Tag: v5.4.54~104
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=38a66f3cdab4b256be1313b64c0394c6dc001b79;p=users%2Fdwmw2%2Flinux.git

btrfs: fix page leaks after failure to lock page for delalloc

commit 5909ca110b29aa16b23b52b8de8d3bb1035fd738 upstream.

When locking pages for delalloc, we check if it's dirty and mapping still
matches. If it does not match, we need to return -EAGAIN and release all
pages. Only the current page was put though, iterate over all the
remaining pages too.

CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 9b214b14a3aaf..1a089a6424221 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1923,7 +1923,8 @@ static int __process_pages_contig(struct address_space *mapping,
 				if (!PageDirty(pages[i]) ||
 				    pages[i]->mapping != mapping) {
 					unlock_page(pages[i]);
-					put_page(pages[i]);
+					for (; i < ret; i++)
+						put_page(pages[i]);
 					err = -EAGAIN;
 					goto out;
 				}