** Changed in: linux (Ubuntu Focal) Importance: Undecided => Medium ** Changed in: linux (Ubuntu Jammy) Importance: Undecided => Medium
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1856871 Title: i/o error if next unused loop device is queried Status in linux package in Ubuntu: Fix Released Status in parted package in Ubuntu: Invalid Status in snapd package in Ubuntu: Invalid Status in systemd package in Ubuntu: Invalid Status in udev package in Ubuntu: Invalid Status in linux source package in Focal: In Progress Status in linux source package in Jammy: Fix Released Bug description: [Impact] * There's an I/O error on fsync() in a detached loop device if it has been previously attached. The issue is that write cache is enabled in the attach path in loop_configure() but it isn't disabled in the detach path; thus it remains enabled in the block device regardless of whether it is attached or not. * fsync() on detached loop devices can be called by partition tools and commands run by sosreport, so the unexpected kernel error message might surprise users or even distract from the actual issue being investigatedr. It might also trigger alerts in logging/monitoring/alerting stacks [Fix] * Disable write cache in the detach path [Test Plan] * Attach and detach an image to a loop device and test fsync return value aterwards # DEV=/dev/loop7 # IMG=/tmp/image # truncate --size 1M $IMG # losetup $DEV $IMG # losetup -d $DEV Before: # strace -e fsync parted -s $DEV print 2>&1 | grep fsync fsync(3) = -1 EIO (Input/output error) Warning: Error fsyncing/closing /dev/loop7: Input/output error [ 982.529929] blk_update_request: I/O error, dev loop7, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 0 prio class 0 After: # strace -e fsync parted -s $DEV print 2>&1 | grep fsync fsync(3) = 0 [Where problems could occur] * The detach path for block devices is modified. Worst case scenario would be an error when detaching loop devices. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1856871/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
