pub fn free_fraction(path: &Path) -> Result<f64>Expand description
How much of the filesystem holding path is still free, as a fraction of
its total size.
f_bavail, not f_bfree: the difference is the root reserve (5% on a
default ext4), which is space the process cannot write into and therefore
not space Mira has. Both terms of the ratio are in blocks of f_bsize, so
the block size cancels and is not in the arithmetic.