Public bug reported: [Impact]
* Under certain conditions, the discard operation on the new ESE DASD may lead to data corruption. [Test Case] * Internal IBM testing [Regression Potential] * ESE DASD / thin provisioning, is the a new subtype of DASD drives specific to s390 architecture. The fix is to not expose discard availability to the kernel, to prevent utilising discard. [Other Info] * Comments from the thin-provisioning feature bug https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1830731 Comment from Jan Hoeppner 2019-09-24 07:16:57 CDT The thin provisioning feature introduces an IOCTL and the discard support to allow userspace tools and filesystems to release unused and previously allocated space respectively. During some internal performance improvements and further tests, the release of allocated space revealed some issues that may lead to data corruption in some configurations when filesystems are mounted with discard support enabled. As we're working on a fix and trying to clarify the situation, it is highly recommended at this point to _not_ enable discard for any filesystem when working with ESE DASDs. mkfs should also be called with discard disabled for ESE DASDs (e.g. mkfs.ext4 -E nodiscard /dev/dasdX). Fixes and clarifications will be provided as soon as possible. Regards, Jan ------- Comment From stefan.haberl...@de.ibm.com 2019-10-01 09:15 EDT------- In addition to Jan's update to _not_ enable discard support I would recommend to completely revert the patch: 7e64db1597fe114b83fe17d0ba96c6aa5fca419a s390/dasd: Add discard support for ESE volumes to prevent the user from enabling the discard support for DASD devices. This patch will also be reverted upstream until further clarification. Regards, Stefan ---- xnox ---- Ubuntu enables discard by default in all the installers, all filesystems, and all layers (e.g. mdadm/lvm/luks discard). Assumption until now, has been that it is harmless, when underlying storage doesn't support discard and always non-harmful when it is supported. I agree, we should revert discard support for ESE volumes in Ubuntu for now. ** Affects: linux (Ubuntu) Importance: Critical Status: New ** Tags: s390x -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1846219 Title: Revert ESE DASD discard support To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1846219/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
