Re: nullfs: contents under mount point not visible via null mount

[Eric Haszlakiewicz <erh%nimenees.com@localhost>]

On September 8, 2014 1:44:28 PM EDT, Toby Karyadi 
<toby.karyadi%gmail.com@localhost> wrote:
>Hi,
>
>Say, if I have the following:
>- a path a/b/c/d
>- a/b/c/d is a mount point for some filesystem
>- an alternate path alt-hier/c, which is a null mount for a/b/c
>
>Then, listing alt-hier/c/d won't show the content of the filesystem 
>mounted on a/b/c/d. This is surprising, since I thought that I'd see
>the 
>content of a/b/c/d. Is this a bug, or my misunderstanding of how the 
>nullfs is supposed to work? I also tried this on FreeBSD 7.1 and got
>the 
>same behavior; hmmpfh.

Based on the description in the man page, notably that it says that null mounts 
work on the overall namespace, it seems like that should work.  I'd say what 
you're seeing is a bug.
Maybe it only figures out the filesystem of the lower layer at mount time, not 
at each vnode lookup?

Eric