overlayfs_set_lower_and_data_fds

composefs::mountcompat

Function overlayfs_set_lower_and_data_fds 

Source 
pub fn overlayfs_set_lower_and_data_fds(
    fs_fd: impl AsFd,
    lower: impl AsFd,
    data: Option<impl AsFd>,
) -> Result<()>
Expand description

Sets the “lowerdir+” and “datadir+” mount options of an overlayfs mount to the provided file descriptors.

On RHEL9 kernels, this constructs a lowerdir string using /proc/self/fd/ paths and sets it via fsconfig_set_string() because file descriptors cannot be set directly.