bug#20366: Strange behaviour of df (GNU coreutils) 8.23

[Benjamin Beier]

Hello,

I am running multiple Gentoo/Funtoo servers and yesterday I noticed the 
output of 'df -a' on the Funtoo systems does not show any information 
about the root partition, although this works fine on all my Gentoo 
systems. I compared the installed versions and after a little 
investigation with upgrades and downgrades on both systems i found out, 
that the problem is caused by coreutils version 8.23 (Funtoo default), 
while coreutils version 8.21 (Gentoo default) works fine.

df -a on 8.21:
rootfs                   3997376 1947348   1823932  52% /
/dev/root                3997376 1947348   1823932  52% /
(...)

df -a on 8.23:
rootfs                         -       -         -    - /
/dev/root                      -       -         -    - /
(...)

I also straced df with both versions and interestingly both versions 
seem to collect valid usage information about the root partition. While 
8.21 is showing this information in the output, 8.23 just decides to 
print dashes for some reason?

I attached the strace and full output of both versions.

strace-df-coreutils-8.23.txt
Description: Text document

output-df-coreutils-8.23.txt
Description: Text document

output-df-coreutils-8.21.txt
Description: Text document

strace-df-coreutils-8.21.txt
Description: Text document

system-info.txt
Description: Text document