tune2fs

Set the volume label:

tune2fs -L gentoo /dev/sda2

Set reserved blocks percentage for root from default 5% to 2%:

tune2fs -m 2 /dev/sda2

Display current status:

tune2fs -l /dev/sda2

Example output:

tune2fs 1.42.9 (4-Feb-2014)
Filesystem volume name:   <none>
Last mounted on:          /boot
Filesystem UUID:          26302869-918a-47d8-b832-19391db8f439
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      ext_attr resize_inode dir_index filetype sparse_super
Filesystem flags:         signed_directory_hash 
Default mount options:    user_xattr acl
Filesystem state:         not clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              62496
Block count:              249856
Reserved block count:     12492
Free blocks:              98501
Free inodes:              62170
First block:              1
Block size:               1024
Fragment size:            1024
Reserved GDT blocks:      256
Blocks per group:         8192
Fragments per group:      8192
Inodes per group:         2016
Inode blocks per group:   252
Filesystem created:       Fri Jun 26 04:30:11 2015
Last mount time:          Thu Mar 24 13:17:42 2016
Last write time:          Thu Mar 24 13:17:42 2016
Mount count:              3
Maximum mount count:      -1
Last checked:             Sun Jan 24 11:31:11 2016
Check interval:           0 (<none>)
Lifetime writes:          1592 MB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:	          128
Default directory hash:   half_md4
Directory Hash Seed:      3f132558-3f21-4b99-926d-55ee5ddeba4a