I have an ext4 filesystem for which I'm trying to use "tune2fs -l". Here is the listing of the filesystem from the "mount" command: # mount | grep share /dev/mapper/VolGroup_Share-LogVol_Share on /share type ext4 (rw,noatime,nodiratime,usrjquota=aquota.user,jqfmt=vfsv0,data=writeback,nobh,barrier=0) When I try to run "tune2fs" on it, I get the following error: # tune2fs -l /dev/mapper/VolGroup_Share-LogVol_Share tune2fs 1.41.12 (17-May-2010) tune2fs: Filesystem has unsupported feature(s) while trying to open /dev/mapper/VolGroup_Share-LogVol_Share Couldn't find valid filesystem superblock. This filesystem was created on this system (i.e. not imported from another system). I have other ext4 filesystems on this server, and they all work with "tune2fs -l". Basic system info: # rpm -qf `which tune2fs` e2fsprogs-1.41.12-18.el6.x86_64 # cat /etc/redhat-release CentOS release 6.5 (Final) # uname -a Linux lnxutil8 2.6.32-504.12.2.el6.x86_64 #1 SMP Wed Mar 11 22:03:14 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux I did a little web searching on this, most of the hits were for much older systems, where (for example) the e2fsprogs only supported up to ext3, but the user had an ext4 filesystem. Obviously that's not the case here. In other words, the filesystem was created with the mkfs.ext4 binary from the same e2fsprogs package as the tune2fs binary I'm trying to use. Anyone ever seen anything like this? Thanks!