Commands tagged Filesystem

Use at your own risk.

# dd if=/dev/zero of=T bs=1024 count=10240;mkfs.ext3 -q T;E=$(echo 'read O;mount -o loop,offset=$O F /mnt;'|base64|tr -d '\n');  echo "E=\$(echo $E|base64 -d);eval \$E;exit;">F;cat <(dd if=/dev/zero bs=$(echo 9191-$(stat -c%s F)|bc) count=1) <(cat T;rm    T)>>F
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.127043 s, 82.5 MB/s
T is not a block special device.
Proceed anyway? (y,n) y
1+0 records in
1+0 records out
9104 bytes (9.1 kB) copied, 0.000116352 s, 78.2 MB/s

(before executing next, make sure /mnt is empty and has nothing mounted, otherwise you can lose files)

# bash F
9191
(I entered 9191, is the password, can be modified in the script)

# l /mnt/
drwx------ 2 root root 12K Jan 31 02:33 lost+found/

# df -h
Filesystem        Size  Used Avail Use% Mounted on
...
/dev/loop0        9.7M  1.1M  8.1M  12% /mnt

# mount
...
/root/F on /mnt type ext3 (rw,relatime,data=ordered)

# umount /mnt 

# head -1 F
E=$(echo cmVhZCBPO21vdW50IC1vIGxvb3Asb2Zmc2V0PSRPIEYgL21udDsK|base64 -d);eval $E;exit;

# E=$(echo cmVhZCBPO21vdW50IC1vIGxvb3Asb2Zmc2V0PSRPIEYgL21udDsK|base64 -d);echo $E
(changed eval x echo)
read O;mount -o loop,offset=$O F /mnt;

In order to create a new encrypted filing system managed by cryptmount,
       you can use the supplied 'cryptmount-setup' program, which can be  used
       by the superuser to interactively configure a basic setup.

       Alternatively,  suppose  that  we  wish to setup a new encrypted filing
       system, that will have a target-name of "opaque".  If we  have  a  free
       disk partition available, say /dev/hdb63, then we can use this directly
       to store the encrypted filing system.  Alternatively,  if  we  want  to
       store  the  encrypted filing system within an ordinary file, we need to
       create space using a recipe such as:

$dd if=/dev/zero of=/home/opaque.fs bs=1M count=512

       and then replace all occurences of '/dev/hdb63' in the  following  with
       '/home/opaque.fs'.   (/dev/urandom  can  be used in place of /dev/zero,
       debatably for extra security, but is rather slower.)

       First,  we  need  to  add  an  entry  in  /etc/cryptmount/cmtab,  which
       describes  the  encryption  that will be used to protect the filesystem
       itself and the access key, as follows:

           opaque {
               dev=/dev/hdb63 dir=/home/crypt
               fstype=ext2 mountoptions=defaults cipher=twofish
               keyfile=/etc/cryptmount/opaque.key
               keyformat=builtin
           }

       Here, we will be using the "twofish" algorithm to  encrypt  the  filing
       system  itself, with the built-in key-manager being used to protect the
       decryption key (to be stored in /etc/cryptmount/opaque.key).

       In  order  to  generate  a  secret  decryption  key   (in   /etc/crypt‐
       mount/opaque.key)  that  will  be  used  to  encrypt  the filing system
itself, we can execute, as root:

$cryptmount --generate-key 32 opaque

       This will generate a 32-byte (256-bit) key, which is known to  be  sup‐
       ported  by the Twofish cipher algorithm, and store it in encrypted form
       after asking the system administrator for a password.

       If we now execute, as root:

$cryptmount --prepare opaque

       we will then be asked for the password that we  used  when  setting  up
       /etc/cryptmount/opaque.key,  which  will  enable  cryptmount to setup a
       device-mapper target (/dev/mapper/opaque).  (If you  receive  an  error
       message  of the form device-mapper ioctl cmd 9 failed: Invalid argument
       , this may mean that you have chosen a key-size that isn't supported by
       your chosen cipher algorithm.  You can get some information about suit‐
       able key-sizes by checking the output  from  "more  /proc/crypto",  and
       looking at the "min keysize" and "max keysize" fields.)

       We  can  now  use  standard tools to create the actual filing system on
       /dev/mapper/opaque:

$mke2fs /dev/mapper/opaque

       (It may be advisable, after the filesystem is first mounted,  to  check
       that  the  permissions of the top-level directory created by mke2fs are
       appropriate for your needs.)

       After executing

$cryptmount --release opaque
$mkdir /home/crypt

       the encrypted filing system is ready for use.  Ordinary users can mount
       it by typing

$cryptmount -m opaque

       or

           cryptmount opaque

       and unmount it using

$cryptmount -u opaque

Dirty:            488064 kB

Filesystem         Mount               Size     Used    Avail %Used fs Type
/dev/mapper/Archiv /srv/Music        108.3G    83.2G    21.8G  80%  ext3   
e2fsck 1.41.12 (17-May-2010)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information

   24809 inodes used (0.34%)
    1835 non-contiguous files (7.4%)
      15 non-contiguous directories (0.1%)
         # of inodes with ind/dind/tind blocks: 9273/5718/0
22256269 blocks used (77.18%)
       0 bad blocks
       1 large file

   20110 regular files
    4690 directories
       0 character device files
       0 block device files
       0 fifos
       0 links
       0 symbolic links (0 fast symbolic links)
       0 sockets
--------
   24800 files

real	3m31.842s
user	0m13.897s
sys	0m8.977s

...
        Children see throughput for  1 readers          = 5751690.50 KB/sec
        Parent sees throughput for  1 readers           = 5743637.82 KB/sec
        Min throughput per process                      = 5751690.50 KB/sec
        Max throughput per process                      = 5751690.50 KB/sec
        Avg throughput per process                      = 5751690.50 KB/sec
        Min xfer                                        = 2097152.00 KB

        Children see throughput for 1 re-readers        = 5186260.00 KB/sec
        Parent sees throughput for 1 re-readers         = 5179126.64 KB/sec
        Min throughput per process                      = 5186260.00 KB/sec
        Max throughput per process                      = 5186260.00 KB/sec
        Avg throughput per process                      = 5186260.00 KB/sec
        Min xfer                                        = 2097152.00 KB

iozone test complete.

laptop:~# locate -e freetype.so | xargs ls -l
lrwxrwxrwx 1 root root     16 2009-08-08 11:49 /usr/lib32/libfreetype.so -> libfreetype.so.6
lrwxrwxrwx 1 root root     21 2009-08-08 11:49 /usr/lib32/libfreetype.so.6 -> libfreetype.so.6.3.20
-rw-r--r-- 1 root root 483556 2009-06-01 14:50 /usr/lib32/libfreetype.so.6.3.20
lrwxrwxrwx 1 root root     21 2009-06-17 15:53 /usr/lib/libfreetype.so -> libfreetype.so.6.3.20
lrwxrwxrwx 1 root root     21 2009-06-17 15:53 /usr/lib/libfreetype.so.6 -> libfreetype.so.6.3.20
-rw-r--r-- 1 root root 551872 2009-06-01 14:40 /usr/lib/libfreetype.so.6.3.20

snd:~/trunk$ du -aB1m|awk '$1 >= 100'
130     ./webdev-tools
178     ./videos/peepcode-027-emacs.mov
102     ./videos/LispCast/Reddit Clone Episode 8 -- Continuations.flv
182     ./videos/LispCast/Reddit Clone Episode 3.flv
879     ./videos/LispCast
1010    ./videos
2138    .

%free -tom
             total       used       free     shared    buffers     cached
Mem:          1010        997         12          0          1        395
Swap:         2047         43       2003
Total:        3057       1041       2016

%sudo dd if=/dev/zero of=/swapfile bs=1024 count=1024000;sudo mkswap /swapfile; sudo swapon /swapfile

1024000+0 records in
1024000+0 records out
1048576000 bytes (1.0 GB) copied, 48.22 s, 21.7 MB/s
Setting up swapspace version 1, size = 1048571 kB
no label, UUID=1c269910-c4f4-441d-a65c-3cd0ff2a4f31

free -tom
             total       used       free     shared    buffers     cached
Mem:          1010        997         13          0          1        400
Swap:         3047         64       2983
Total:        4057       1061       2996

150M    /home/jharvey/scratch
100M    /home/jharvey
567M    /home/jdoe/migration

/dev/sda1   on  /                         type  ext3        (rw,relatime,errors=remount-ro)
tmpfs       on  /lib/init/rw              type  tmpfs       (rw,nosuid,mode=0755)
/proc       on  /proc                     type  proc        (rw,noexec,nosuid,nodev)
sysfs       on  /sys                      type  sysfs       (rw,noexec,nosuid,nodev)
varrun      on  /var/run                  type  tmpfs       (rw,nosuid,mode=0755)
varlock     on  /var/lock                 type  tmpfs       (rw,noexec,nosuid,nodev,mode=1777)
udev        on  /dev                      type  tmpfs       (rw,mode=0755)
tmpfs       on  /dev/shm                  type  tmpfs       (rw,nosuid,nodev)
devpts      on  /dev/pts                  type  devpts      (rw,noexec,nosuid,gid=5,mode=620)
fusectl     on  /sys/fs/fuse/connections  type  fusectl     (rw)
securityfs  on  /sys/kernel/security      type  securityfs  (rw)