[murphyslaw]

df just uses C library calls which use system calls.

If you're going to implement something like this then ffs do it right. I don't know the "easy" way to fix this, but in any case if something is supposed to be transparently free and available then standard tools using standard calls should see it as free and available, with specialized user space tools that can look behind the screens when needed.

[moring]

For clarification, by "df has a bug" I meant that it doesn't produce the result it should given the situation, but not necessarily that the problem is located in df's own source code, vs. the kernel, other process, library etc.

[dylan604]

if the system is not reporting the space as free, then how in the world does the bug belong to df. it is the system not reporting it correctly.