** Description changed: + [Impact] + + * The bcache code in Bionic lacks several fixes to handle + I/O errors in both backing devices and caching devices. + + * Partial or permanent errors in backing or caching devices, + specially in writeback mode, can lead to data loss and/or + the application is not notified about failed I/O requests. + + * The bcache device might remain available for I/O requests + even if backing device is offline, so writes are undefined. + + [Test Case] + + * Detailed test cases/steps for the behavior of almost every + patch with code logic changes are provided in bug comments. + + * The patchset has been tested for regressions on each cache + mode (writethrough, writeback, writearound, none) with the + xfstests test suite (on ext4), fio (random read-write) and + iozone (several read/write tests). + + [Regression Potential] + + * The patchset is relatively large and touches several areas + in bcache code, however, synthetic testing of the patches + has been performed, and extensive regression/stress tests + were run (as mentioned in Test Case section). + + * Many patches in the patchset are 'Fixes' patches to other + patches, and no further 'Fixes' currently exist upstream. + + [Other Info] + + * Canonical Field Eng. deploys bcache+writeback extensively + (e.g., BootStack, UA cloud, except rare all-flash cases). + + + [Original Bug Description] + This is a request for a backport of the following upstream patch from 4.18: "bcache: stop bcache device when backing device is offline" https://github.com/torvalds/linux/commit/0f0709e6bfc3ce4e8e1c0e8573490c45f76cfeee Field engineering uses bcache quite extensively and it would be good to have this in the GA/bionic kernel.
** Summary changed: - [4.15] bcache device is accessible even if a backing device is not (writeback mode) + bcache: risk of data loss on I/O errors in backing or caching devices -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1829563 Title: bcache: risk of data loss on I/O errors in backing or caching devices To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1829563/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
