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 c55c2ae335eae1f48ae7a54343cab5f80b6158b0..6d2bfbb63d9bae4216dc6e9d6a91ab52f50b72c9 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1721,7 +1721,8 @@ 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;
                                }