122             let count: usize = (range.lba_end - range.lba_start).try_into().unwrap();  in read_at()
127                 BlockDevice::read_at(self, range.lba_start, count, buf_slice)?;  in read_at()
136                 BlockDevice::read_at(self, range.lba_start, 1, &mut temp[..])?;  in read_at()
158             let count: usize = (range.lba_end - range.lba_start).try_into().unwrap();  in write_at()
162                 BlockDevice::write_at(self, range.lba_start, count, buf_slice)?;  in write_at()
171                 BlockDevice::read_at(self, range.lba_start, 1, &mut temp[..])?;  in write_at()
174                 BlockDevice::write_at(self, range.lba_start, 1, &temp[..])?;  in write_at()
200     pub lba_start: usize, // 起始块的lba_id  field
241             lba_start: lba_id,  in next_block()
253         let lba_start = self.begin / blk_size;  in next_multiblock()  localVariable
259             || lba_start == lba_end  in next_multiblock()
270             lba_start: lba_start,  in next_multiblock()
315         return (self.lba_start << self.blk_size_log2) + self.begin;  in origin_begin()
319         return (self.lba_start << self.blk_size_log2) + self.end;  in origin_end()