LinuxQuestions.org - resize a loopback file

Well that kind of depends on what kind of filesystem is used for the loopback file. But each filesystems should have tools to get that done. Anyways here is how I did it for an ext2 filesystem:

Code:

# cd /tmp

# mkdir mnt

# dd if=/dev/zero of=image bs=1k count=1024

1024+0 records in

1024+0 records out

# mke2fs -i 1024 -b 1024 -m 5 -F -v image

mke2fs 1.24a (02-Sep-2001)

Filesystem label=

OS type: Linux

Block size=1024 (log=0)

Fragment size=1024 (log=0)

1024 inodes, 1024 blocks

51 blocks (4.98%) reserved for the super user

First data block=1

1 block group

8192 blocks per group, 8192 fragments per group

1024 inodes per group



Writing inode tables: done                            

Writing superblocks and filesystem accounting information: done



This filesystem will be automatically checked every 23 mounts or

180 days, whichever comes first.  Use tune2fs -c or -i to override.

# mount image mnt -t ext2 -o loop

# dd if=/dev/zero of=image bs=1k count=1024 seek=1024

1024+0 records in

1024+0 records out

# e2fsck -f image

e2fsck 1.24a (02-Sep-2001)

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



image: *** WARNING: Filesystem still has errors ***



image: 11/1024 files (0.0% non-contiguous), 135/1024 blocks

# resize2fs image 2048

resize2fs 1.24a (02-Sep-2001)

The filesystem on image is now 2048 blocks long.

# mount image mnt -t ext2 -o loop

# cd mnt

# df -k .

Filesystem          1k-blocks      Used Available Use% Mounted on

/tmp/image                1915        2      1852  1% /tmp/mnt

# cd ..  

# umount mnt 

# rm -rf mnt image

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