Joseph, I encounter this problem also in ubuntu 15.04 with a linux- image-3.19.0-15-generic.
I can append some additional information how to reproduce this issue. After my analysis I found dependence: drive filesystem vs backing file filesystem: Create backing file on a drive that is formatted to NTFS dd if=/dev/zero of=./Test.img bs=1M count=1024 Find free loop device losetup -f Connect backing file with a loop device [ losetup -f ], for example: /dev/loop3 losetup /dev/loop3 ./Test.img Create filesystem on backing file via loop device mkfs.ext4 /dev/loop3 Mount backing file via loop device into /mnt directory mount -t ext4 /dev/loop3 /mnt/ Write some data on backing file via loop device dd if=/dev/zero of=/mnt/Test.file bs=1M count=512 After this procedure you will be see errors on a kernel log: [ 1370.381087] blk_update_request: I/O error, dev loop3, sector 25864 [ 1370.789277] blk_update_request: I/O error, dev loop3, sector 29960 [ 1371.193360] blk_update_request: I/O error, dev loop3, sector 34056 ** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1526537 Title: blk_update_request: I/O error To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1526537/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs