linux-kernel - [PATCH 4.14 20/64] btrfs: fix page leaks after failure to lock page for delalloc

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Message-Id: <20200727134912.046122358@linuxfoundation.org>
Date:   Mon, 27 Jul 2020 16:03:59 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Filipe Manana <fdmanana@...e.com>,
        Nikolay Borisov <nborisov@...e.com>,
        Robbie Ko <robbieko@...ology.com>,
        David Sterba <dsterba@...e.com>
Subject: [PATCH 4.14 20/64] btrfs: fix page leaks after failure to lock page for delalloc

From: Robbie Ko <robbieko@...ology.com>

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@...r.kernel.org # 4.14+
Reviewed-by: Filipe Manana <fdmanana@...e.com>
Reviewed-by: Nikolay Borisov <nborisov@...e.com>
Signed-off-by: Robbie Ko <robbieko@...ology.com>
Reviewed-by: David Sterba <dsterba@...e.com>
Signed-off-by: David Sterba <dsterba@...e.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/btrfs/extent_io.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1721,7 +1721,8 @@ static int __process_pages_contig(struct
 				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;
 				}