我刚刚从 18.10（之前从 Debian Stretch）更新到 19.04。升级后，任何写入操作都会使整个系统（包括鼠标）冻结 3 秒或更长时间。这很奇怪，因为升级之前没有发生过，而且系统是一样的。hdparm 报告 517 MB/s 读取和 smart 没有显示任何错误：
sudo smartctl -a /dev/sdb
smartctl 6.6 2017-11-05 r4594 [x86_64-linux-5.0.0-13-generic] (local build)
Copyright (C) 2002-17, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF INFORMATION SECTION ===
Device Model: LITEON L8H-128V2G-11 M.2 2280 128GB
Serial Number: BR0RJW291CB0075GB0VE
Firmware Version: F87110C
User Capacity: 128.035.676.160 bytes [128 GB]
Sector Size: 512 bytes logical/physical
Rotation Rate: Solid State Device
Form Factor: M.2
Device is: Not in smartctl database [for details use: -P …