mac@ubuntu-desktop:~$ dmesg | grep EXT4
[    4.553997] EXT4-fs (sda2): mounted filesystem without journal. Opts: (null)
[    5.189410] EXT4-fs error (device sda2): __ext4_get_inode_loc:3630: inode #5114400: block 20447425: comm init: unable to read itable block
[    7.898148] EXT4-fs error (device sda2): __ext4_get_inode_loc:3630: inode #4728389: block 18875012: comm ureadahead: unable to read itable block
[    9.018945] EXT4-fs error (device sda2): ext4_find_entry:1209: inode #4985039: comm ureadahead: reading directory lblock 0
[    9.021720] EXT4-fs error (device sda2): ext4_find_entry:1209: inode #4984277: comm ureadahead: reading directory lblock 0
[   12.145123] EXT4-fs (sda2): re-mounted. Opts: errors=remount-ro,discard
mac@ubuntu-desktop:~$