6.3. Resizing an Ext4 File System
resize2fs /mount/device node
resize2fscommand can also decrease the size of an unmounted ext4 file system:
resize2fs /dev/device size
resize2fsutility reads the size in units of file system block size, unless a suffix indicating a specific unit is used. The following suffixes indicate specific units:
s— 512 byte sectors
resize2fsautomatically expands to fill all available space of the container, usually a logical volume or partition.