[gentoo-user] Difficulty with nfs mounts and binding

[gentoo-user] Difficulty with nfs mounts and binding

[Peter Humphrey]

Hello list,

My LAN server uses my workstation as a portage compute host, in which its
portage directories are NFS-exported to a choot on the workstation. It also
has a separate rescue system, which I want to handle the same way.

I have the following relevant fstab entries on the server:

/dev/sda5 /                   ext4    relatime,errors=remount-ro      0 1
/dev/sda2 /boot               vfat    noauto,codepage=850             0 2
/dev/sda8 /var/cache/packages ext4    relatime,nodev,nosuid,shared    0 3
/dev/sda4 /mnt/rescue         ext4    relatime,noauto                 0 2
/dev/sda2 /mnt/rescue/boot    vfat    noauto,codepage=850             0 0
tmpfs     /var/tmp/portage    tmpfs   relatime,uid=portage,gid=portage,mode=0775 0 0
tmpfs     /mnt/rescue/var/tmp/portage tmpfs ro,relatime,uid=portage,gid=portage,mode=0775 0 0
# NFS-export portage to bin-host:
/var/db/repos/gentoo    /mnt/nfs/portage                ext4    bind            0 0
/var/cache/packages     /mnt/nfs/portage.packages       ext4    bind,shared     0 0
/var/cache/distfiles    /mnt/nfs/portage.distfiles      ext4    bind,shared     0 0
/mnt/nfs/portage.packages   /mnt/nfs/rescue.packages    ext4    bind,noauto     0 0
/mnt/nfs/portage.distfiles  /mnt/nfs/rescue.distfiles   ext4    bind,noauto     0 0

Now, after a clean boot I get this:
$ mount | grep portage
tmpfs on /var/tmp/portage type tmpfs (rw,relatime,mode=775,uid=250,gid=250)
/dev/sda5 on /mnt/nfs/portage type ext4 (rw,relatime,errors=remount-ro)   <---
/dev/sda8 on /mnt/nfs/portage.packages type ext4 (rw,nosuid,nodev,relatime)
/dev/sda5 on /mnt/nfs/portage.distfiles type ext4 (rw,relatime,errors=remount-ro)  <---

I get the same if I boot after rc-update del nfs default, but of course I need
that for NFS export.

Why does /dev/sda5 appear under /mnt/nfs, as well as being the root FS?

Is my understanding of the various mount options to blame?

-- 
Regards,
Peter.