Comment # 4 on bug 1149148 from Kai Dupke

(In reply to Arvin Schnell from comment #3)
> Depends on what is reasonable. It will likely need research for every
> filesystem.

I wonder if this has to be a factor, or if a fixed amount (i.e. 250GB) would do
as well.

> Another problem is that the maximal size for ext4 is set to 16 TiB. This
> is done since ext4 needs the 64bit feature to handle larger devices
> (https://www.netways.de/blog/2017/12/13/how-to-use-ext4-beyond-16tib/).
> E.g. an ext4 normally created on SLE12 SP3 cannot be grown beyond 16 TiB.
> So strictly speaking the 64bit feature must be checked (using dumpe2fs).

In the shrinking case, this can't be an issue, can it be? In case a size bigger
then 16TB, 64bit must be already enabled, right? So shrinking does not need to
check this flag.

I wonder if it is checked for extending, but at least for openSUSE I am not
aware of any notice when I extended a FS beyond 16TB (this system alone has 2
FS > 16TB) resp. created a FS that big.