Using symbolic links to simulate direct mounts

[Brendan Eich]

In article <9104171516.AA14281 at ZoSo.lerc.nasa.gov>, fsfacca at ZOSO.LERC.NASA.GOV (Tony Facca) writes:
> I would like to use an indirect automount to access release notes which I 
> have moved to a file server.
> [. . .]
> What I want to do is create a symlink between /r/relnotes and /usr/relnotes.
> When I do that, and issue the "relnotes" command, the automounter fails to
> mount the /usr/relnotes directory properly and the command returns:
> 
> 	Sorry, but no products have release notes installed
> 
> If I cd into /usr/relnotes directory, the mount occurs.  But "relnotes" still
> says, "Sorry,.."
> 
> Does this mean that something is not linked properly.  We've had success using
> symlinks to simulate direct mounts for other applications.  Does anyone have
> any idea what might be going on?

The problem is that /usr/sbin/relnotes, a shell script, uses find(1) to
search for regular files matching 'ch*.z' under /usr/relnotes, resulting
in readdir NFS operations, while automount mounts remote filesystems only
in response to lookup (and readlink for direct maps) NFS operations.

This limitation is discussed in automount(1M)'s NOTES section, in the
paragraph beginning "An ls(1) listing ....", and applies only to indirect
maps in the case at hand (if /usr/relnotes were direct-mapped to a remote
filesystem, find would stat it and follow the automount-emulated symlink,
causing the remote filesystem to be mounted).

Direct maps are supported in IRIX 4.0.

/be