+ dd if=/dev/zero of=foo bs=1M count=1 seek=2000
1+0 records in
1+0 records out
1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.00122621 s, 855 MB/s
+ sudo kpartx -s -v -a foo
+ sudo parted foo -s -- mklabel msdos
+ sudo parted foo -s -- mkpart primary ext4 2M 2G
+ sudo kpartx -s -v -a /dev/loop0
add map loop0p1 (252:0): 0 4093952 linear 7:0 4096
+ sudo mkfs -t ext4 /dev/mapper/loop0p1
mke2fs 1.43.1 (08-Jun-2016)
Discarding device blocks:   4096/511744             done                            
Creating filesystem with 511744 4k blocks and 128000 inodes
Filesystem UUID: 022fc90c-6325-41ae-a480-564600ca533c
Superblock backups stored on blocks: 
	32768, 98304, 163840, 229376, 294912

Allocating group tables:  0/16     done                            
Writing inode tables:  0/16     done                            
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information:  0/16     done

+ sudo sfdisk -l foo
Disk foo: 2 GiB, 2098200576 bytes, 4098048 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x88cf66dd

Device Boot Start     End Sectors Size Id Type
foo1         4096 4098047 4093952   2G 83 Linux
+ sudo kpartx -s -v -d foo
del devmap : loop0p1
loop deleted : /dev/loop0
+ qemu-img resize -f raw foo 8G
Image resized.
+ sudo kpartx -s -v -a foo
add map loop0p1 (252:0): 0 4093952 linear 7:0 4096
+ sudo kpartx -s -v -d /dev/loop0
del devmap : loop0p1
+ sudo growpart /dev/loop0 1
CHANGED: partition=1 start=4096 old: size=4093952 end=4098048 new: size=16773087,end=16777183
+ echo 0
0
+ sudo kpartx -s -v -a /dev/loop0
add map loop0p1 (252:0): 0 16773087 linear 7:0 4096
+ sudo e2fsck -f -y -E discard /dev/mapper/loop0p1
e2fsck 1.43.1 (08-Jun-2016)
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
/dev/mapper/loop0p1: 11/128000 files (0.0% non-contiguous), 17736/511744 blocks
+ sudo resize2fs /dev/mapper/loop0p1
resize2fs 1.43.1 (08-Jun-2016)
Resizing the filesystem on /dev/mapper/loop0p1 to 2096635 (4k) blocks.
The filesystem on /dev/mapper/loop0p1 is now 2096635 (4k) blocks long.

+ sudo zerofree /dev/mapper/loop0p1
+ sudo kpartx -s -v -d foo
del devmap : loop0p1
loop deleted : /dev/loop0
+ rm foo