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-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5909ca110b29aa16b23b52b8de8d3bb1035fd738;p=linux.git

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>
---

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 95313bb7fe40d..72c836b54efc0 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1999,7 +1999,8 @@ 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;
 				}