sfdisk fails to overwrite disks that contain a pre-existing linux partition
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
util-linux (Ubuntu) |
Confirmed
|
Undecided
|
Unassigned |
Bug Description
This command should non-interactively obliterate whatever partition table is on /dev/sde, and create a new table with a linux partition that spans the whole disk:
$ sfdisk --label gpt /dev/sde <<< 'start=2048, type='"$(sfdisk --label gpt -T | awk '{IGNORECASE = 1;} /linux filesystem/{print $1}')"
Sometimes it works correctly; sometimes not. It seems to work correctly as long as the pre-existing partition table does not already contain a linux partition. E.g. if the existing table just contains an exFAT partition, there's no issue. But if there is a linux partition, it gives this output:
-----
Old situation:
Device Start End Sectors Size Type
/dev/sde1 2048 1953525134 1953523087 931.5G Linux root (x86-64)
>>> Created a new GPT disklabel (GUID: <redacted>).
/dev/sde1: Sector 2048 already used.
Failed to add #1 partition: Numerical result out of range
Leaving.
-----
sfdisk should *always* overwrite the target disk unconditionally. This is what the dump of the target drive looks like in the failure case:
$ sfdisk -d /dev/sdd
label: gpt
label-id: <redacted>
device: /dev/sdd
unit: sectors
first-lba: 34
last-lba: 1953525134
grain: 33553920
sector-size: 512
/dev/sdd1 : start= 2048, size= 1953523087, type=4F68BCE3-
$ sfdisk -v
sfdisk from util-linux 2.36.1
Even the workaround is broken. That is, running the following:
$ wipefs -a /dev/sde
should put the disk in a state that can be overwritten. But whatever residual metadata it leaves behind still triggers the sfdisk bug:
$ sfdisk --label gpt /dev/sde <<< 'start=2048, type='"$(sfdisk --label gpt -T | awk '{IGNORECASE = 1;} /linux filesystem/{print $1}')"
Checking that no-one is using this disk right now ... OK
Disk /dev/sde: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: Disk
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 4096 bytes / 33553920 bytes
>>> Created a new GPT disklabel (GUID: <redacted>).
/dev/sde1: Sector 2048 already used.
Failed to add #1 partition: Numerical result out of range
Leaving.
Workaround 2 (also fails):
$ dd if=/dev/zero of=/dev/sde bs=1M count=512
$ sfdisk -d /dev/sde
sfdisk: /dev/sde: does not contain a recognized partition table
^ the nuclear option did the right thing, but sfdisk still fails to partition the drive (same error).
The *only* workaround that works is an interactive partitioning with gdisk.
Status changed to 'Confirmed' because the bug affects multiple users.