Dev1 Galaxy Forum / mkfs.ext4: invalid blocks offset=X on device device.img

Re: mkfs.ext4: invalid blocks offset=X on device device.img

dummy@example.com (0xf4b10) — Thu, 04 Oct 2018 01:20:15 +0000

fsmithred wrote:

What you tried looks right to me, but the man page for mke2fs doesn't actually say what units to use for offset. Further down the page where it talks about specifying the location of the journal, the wording suggests that you might need to use 'offset=1M'.
One thing you did looks odd - why partition with cfdisk if you want gpt? gdisk is the right tool for that.

Well, it happens that I was just forgetting to pass a -E flag to the mkfs command. After that, it was possible to create the filesystems

Plentyn wrote:

What about:
loopdev=$(losetup -P -f --show imagem-zero.img)
mkfs.ext4 ${loopdev}p1
losetup -d $loopdev
(Or something along these lines)

Nice, losetup did the trick easily

Re: mkfs.ext4: invalid blocks offset=X on device device.img

dummy@example.com (Plentyn) — Tue, 02 Oct 2018 21:44:04 +0000

What about:

loopdev=$(losetup -P -f --show imagem-zero.img)
mkfs.ext4 ${loopdev}p1
losetup -d $loopdev

(Or something along these lines)

Re: mkfs.ext4: invalid blocks offset=X on device device.img

dummy@example.com (fsmithred) — Tue, 02 Oct 2018 12:26:11 +0000

What you tried looks right to me, but the man page for mke2fs doesn't actually say what units to use for offset. Further down the page where it talks about specifying the location of the journal, the wording suggests that you might need to use 'offset=1M'.

One thing you did looks odd - why partition with cfdisk if you want gpt? gdisk is the right tool for that.

mkfs.ext4: invalid blocks offset=X on device device.img

dummy@example.com (0xf4b10) — Tue, 02 Oct 2018 02:57:05 +0000

My goal is to create a regular file and within it make a partition and file systems (literally a virtual hard drive) and finally mount it, so I did:

sudo dd if=/dev/zero of=imagem-zero.img count=20480000

To create the file with aprox 20Gb. Then I've partitioned with cfdisk, after that the status of the file was:

$ gdisk -l imagem-zero.img
GPT fdisk (gdisk) version 1.0.1
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
Disk imagem-zero.img: 40960000 sectors, 19.5 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 544A9633-7FA3-4BE8-BEE7-612C151A4504
Partition table holds up to 128 entries
First usable sector is 2048, last usable sector is 40959966
Partitions will be aligned on 2048-sector boundaries
Total free space is 0 sectors (0 bytes)
Number Start (sector) End (sector) Size Code Name
1 2048 16779263 8.0 GiB 8304
2 16779264 40959966 11.5 GiB 8302

Now I want to make the file system ext4 in both these two sectors but I'm failing with the error message in the title of the question:

$ sudo mkfs.ext4 imagem-zero.img offset=$((2048*512))

mke2fs 1.43.4 (31-Jan-2017)
mkfs.ext4: invalid blocks 'offset=1048576' on device 'imagem-zero.img'

$ sudo mkfs.ext4 imagem-zero.img offset=$((2048))

mke2fs 1.43.4 (31-Jan-2017)
mkfs.ext4: invalid blocks 'offset=2048' on device 'imagem-zero.img'

My question is, how to find the correct offset to make the FS on both of the partitions? Thanks in advance.
Suggestions on how to reach my goal are also welcome