Package: util-linux
Version: 2.36.1-8
Severity: wishlist
File: /sbin/wipefs
wipefs is not recursive, which leads to this unexpected behaviour:
root@dban:~# blkid
/dev/vda: TYPE="squashfs"
/dev/vdb1: LABEL_FATBOOT="ESP" LABEL="ESP" UUID="6BE7-C309"
BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="ESP"
PARTUUID="0dbbd176-3208-4461-a991-9b6b6f9"
/dev/vdb2: LABEL="root" UUID="2238872e-f5f5-4704-944c-9974c2b41238"
BLOCK_SIZE="1024" TYPE="ext4" PARTLABEL="root" PARTUUID="289c1ba2-297b-4b84-ad"
root@dban:~# wipefs -a /dev/vdb
/dev/vdb: 8 bytes were erased at offset 0x00000200 (gpt): 45 46 49 20 50 41
52 54
/dev/vdb: 8 bytes were erased at offset 0x0c1ffe00 (gpt): 45 46 49 20 50 41
52 54
/dev/vdb: 2 bytes were erased at offset 0x000001fe (PMBR): 55 aa
/dev/vdb: calling ioctl to re-read partition table: Success
root@dban:~# pvcreate /dev/vdb
Physical volume "/dev/vdb" successfully created.
root@dban:~# vgcreate x /dev/vdb
Volume group "x" successfully created
root@dban:~# lvcreate --size=32M --name y x
WARNING: vfat signature detected on /dev/x/y at offset 82. Wipe it? [y/n]: y
Wiping vfat signature on /dev/x/y.
WARNING: vfat signature detected on /dev/x/y at offset 0. Wipe it? [y/n]: y
Wiping vfat signature on /dev/x/y.
WARNING: vfat signature detected on /dev/x/y at offset 510. Wipe it? [y/n]:
y
Wiping vfat signature on /dev/x/y.
Logical volume "y" created.
If wipefs was recursive, this sort of thing wouldn't happen.
I guess libblkid already provides the necessary functionality, and
zeroing out a few extra blocks is a small I/O cost for the large gain in
"principle of least surprise".
The manpage implicitly suggests to work around this by doing "wipefs /dev/vdb*".
This works if you are root and the device is visible to the kernel, as above.
However you are working "rootless" and thus cannot e.g. "sudo kpartx -a", you
can't do that.
You could pass offsets to "wipefs --offset=$((1024*1024)) /tmp/dummy.img", but
that's an error-prone pain.
PS: on rereading the manpage, it sounded like maybe --force also meant
--recursive, but I tested that and it didn't DWIM:
<resetting everything to initial state>
root@dban:~# blkid
/dev/vda: TYPE="squashfs"
/dev/vdb1: LABEL_FATBOOT="ESP" LABEL="ESP" UUID="C8A7-56D5"
BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="ESP"
PARTUUID="fdbd4fa2-079b-4a2b-930d-98afded"
/dev/vdb2: LABEL="root" UUID="4f6d7a44-6274-40df-945f-9323c5be3ae9"
BLOCK_SIZE="1024" TYPE="ext4" PARTLABEL="root" PARTUUID="0af92335-b840-4e69-b0"
root@dban:~# wipefs -fa /dev/vdb
/dev/vdb: 8 bytes were erased at offset 0x00000200 (gpt): 45 46 49 20 50 41
52 54
/dev/vdb: 8 bytes were erased at offset 0x0c1ffe00 (gpt): 45 46 49 20 50 41
52 54
/dev/vdb: 2 bytes were erased at offset 0x000001fe (PMBR): 55 aa
-- System Information:
Debian Release: 11.0
APT prefers stable-updates
APT policy: (990, 'stable-updates'), (990, 'stable-security'), (990,
'stable'), (500, 'proposed-updates'), (500, 'unstable'), (500, 'testing'), (1,
'experimental')
Architecture: amd64 (x86_64)
Kernel: Linux 5.10.0-8-amd64 (SMP w/8 CPU threads)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE,
TAINT_UNSIGNED_MODULE
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages util-linux depends on:
ii libaudit1 1:3.0-2
ii libblkid1 2.36.1-8
ii libc6 2.32-4
ii libcap-ng0 0.7.9-2.2+b1
ii libcrypt1 1:4.4.18-4
ii libmount1 2.36.1-8
ii libpam0g 1.4.0-9
ii libselinux1 3.1-3
ii libsmartcols1 2.36.1-8
ii libsystemd0 247.3-6
ii libtinfo6 6.2+20201114-2
ii libudev1 247.3-6
ii libuuid1 2.36.1-8
ii login 1:4.8.1-1
ii zlib1g 1:1.2.11.dfsg-2
util-linux recommends no packages.
Versions of packages util-linux suggests:
ii dosfstools 4.2-1
ii kbd 2.3.0-3
ii util-linux-locales 2.36.1-8
-- no debconf information
