In bch_mca_scan(), the return value should not be the number of freed btree
nodes, but the number of pages of freed btree nodes.
Signed-off-by: NTang Junhui <tang.junhui@zte.com.cn>
Reviewed-by: NMichael Lyle <mlyle@lyle.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>