resizing / breaks /dev/disk/by-partlabel/ROOT

[mischief]

using extend-filesystems.service results in /dev/disk/by-partlabel/ROOT going missing. the partition information is also missing from blkid -o -p /dev/vda9.

running partx -u after e.g. cgpt resize/resize2fs seems to fix the partition information and partlabel symlink.

[vcaputo]

I'll poke a bit at this...

[crawford]

@mischief I heard you uncovered some interesting behavior from cgpt.

[mischief]

@crawford yes, running cgpt resize /dev/vda9 (or whatever ROOT is) is what causes the bug. extend-filesystems.service is basically doing that.

[crawford]

@dm0- was telling me that cgpt wrote a new partlabel to the kernel but didn't persist it to disk, which is why partx (which reads the label from the disk) fixes the information.

[vcaputo]

ah, I didn't poke at this yet, sounds like dm0 has identified the probable root cause though. So we've got a cgpt bug to fix here?

[vcaputo]

for posterity: this turned out to simply be an off by one error in the cgpt resize code.