Comment 23 for bug 1526537

I can confirm that the error messages on Ubuntu 16.04 (daily) still exist but it seems that it is not as bad as it looks.

I followed the steps which Marcin described in comment #16. Instead of

> Write some data on backing file via loop device
> dd if=/dev/zero of=/mnt/Test.file bs=1M count=512

I copied a known iso file to the created loop device
dd if=lubuntu-14.04.4-desktop-amd64.iso of=/mnt/Test.file bs=1M

I got also some error messages as described in previous comments but md5sum said

md5sum lubuntu-14.04.4-desktop-amd64.iso && md5sum /mnt/Test.file

0b0fc8652afe0761edc3ed33e1b199f0 lubuntu-14.04.4-desktop-amd64.iso
0b0fc8652afe0761edc3ed33e1b199f0 /mnt/Test.file

Then I unmounted the test image and checked it for errors.

umount /mnt/
fsck -pvcf ./Test.img

...and I got:

fsck from util-linux 2.27.1
./Test.img: Updating bad block inode.

          12 inodes used (0.02%, out of 65536)
           0 non-contiguous files (0.0%)
           0 non-contiguous directories (0.0%)
             # of inodes with ind/dind/tind blocks: 0/0/0
             Extent depth histogram: 3/1
      201308 blocks used (76.79%, out of 262144)
           0 bad blocks
           1 large file

           1 regular file
           2 directories
           0 character device files
           0 block device files
           0 fifos
           0 links
           0 symbolic links (0 fast symbolic links)
           0 sockets
------------
           3 files