FS tools

dumps FS informations: dumpe2fs

inode: means a file

dumpe2fs -h /dev/sda1

outputs:

Filesystem OS type:       Linux
Inode count:              9707520 #max number of files
Block count:              38812416 #max number of blocks
Reserved block count:     1940620
Free blocks:              33756140 #
Free inodes:              9545389  #

tune FS settings: tune2fs

!! never use on a mounted FS !!

tune2fs

set number of mount before checking FS

tune2fs -c 3 /dev/sdb1

=>

tune2fs 1.43.4 (31-Jan-2017)
Setting maximal mount count to 3

set time interval before checking FS

tune2fs -i 60d /dev/sdb1

=>

tune2fs 1.43.4 (31-Jan-2017)
Setting interval between checks to 5184000 seconds

check:

dumpe2fs -h /dev/sdb1 | grep interval

set number of reserved blocks

prevent user to fullfill FS

tune2fs -m 3 /dev/sdb1

=>

tune2fs 1.43.4 (31-Jan-2017)
Setting reserved blocks percentage to 3% (14667 blocks)

debugfs

!! never use on a mounted FS !!

dumpe + tune FS

debugfs -w /dev/sdb1

FS stats

stats

=>

Filesystem volume name:   <none>
Last mounted on:          /media/pi/CDROM
Filesystem UUID:          41d6539d-342e-4c2b-93f3-c941525d29b3
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum
Filesystem flags:         signed_directory_hash 
Default mount options:    user_xattr acl
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              122400
Block count:              488907
Reserved block count:     14667
Free blocks:              471589
Free inodes:              122388
First block:              0
Block size:               4096
Fragment size:            4096
Group descriptor size:    64
Reserved GDT blocks:      238

File stats

stat test.txt

=>

Inode: 13   Type: regular    Mode:  0644   Flags: 0x80000
Generation: 1782112958    Version: 0x00000000:00000001
User:     0   Group:     0   Project:     0   Size: 5
File ACL: 0    Directory ACL: 0
Links: 1   Blockcount: 8
Fragment:  Address: 0    Number: 0    Size: 0
 ctime: 0x5e95a4c1:dc281c1c -- Tue Apr 14 13:55:45 2020
  atime: 0x5e95a4c1:dc281c1c -- Tue Apr 14 13:55:45 2020
   mtime: 0x5e95a4c1:dc281c1c -- Tue Apr 14 13:55:45 2020
   crtime: 0x5e95a4c1:dc281c1c -- Tue Apr 14 13:55:45 2020
   Size of extra inode fields: 32
   Inode checksum: 0x8be005b7
   EXTENTS:
   (0):33008

lsdel: list deleted file undel: undelete a file

FSCK

fsck - check and repair a Linux filesystem

!! never use on a mounted FS !!

fsck -v /dev/sdb1

=>

fsck from util-linux 2.29.2
 e2fsck 1.43.4 (31-Jan-2017)
 /dev/sdb1: clean, 13/122400 files, 17319/488907 blocks (check after next mount)