From: Robbie Ko <robbieko@synology.com>
Date: Mon, 20 Jul 2020 09:42:09 +0800
Git-commit: 5909ca110b29aa16b23b52b8de8d3bb1035fd738
Patch-mainline: 5.8
References: bsc#1175149
Subject: [PATCH] btrfs: fix page leaks after failure to lock page for
 delalloc

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: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/extent_io.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 2af849eb24f5..e5bb90899de7 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1825,7 +1825,8 @@ 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;
 				}
-- 
2.26.2