# df -h /dev/mapper/vg0-storage 1.5T 403G 1012G 29% /storage # mount /dev/mapper/vg0-storage on /storage type ext4 (rw,noatime,data=ordered) # umount /storage/ # umount /storage/ umount: /storage/: not mounted epsilon kristianf # umount /dev/vg0/storage umount: /dev/vg0/storage: not mounted epsilon kristianf # resize2fs /dev/vg0/storage 500G resize2fs 1.42.13 (17-May-2015) resize2fs: Device or resource busy while trying to open /dev/vg0/storage Couldn't find valid filesystem superblock.