Re: [gamin] NFS mounts

[Daniel Veillard <veillard redhat com>]

On Tue, Jul 12, 2005 at 08:09:04PM -0400, John McCutchan wrote:
> Yo,
> 
> Daniel, I am wondering how gamin handles NFS mounts. FAM used portmap to
> communicate with remote FAM servers.

  yes but that was unstable, a dependancy and a security mess.

> Gamin doesn't do anything like this right?

  right !

> Are there any plans to handle remote file systems?

  directly no. The curren state is the following as far as I can tell:
    - NFS: local modifications are reported by the kernel when using
           dnotify, remote modifications are not reported, unless a
	   local event forces a rescan of the watched directory
    - AFS: feedback seems to indicate home mounted from AFS work better
           with gamin/dnotify than famd
    - CIFS: seems the conjunction of CIFS and dnotify in the shipped kernel
            doesn't work well, making umounts impossible.

It could be possible to sense filesystems and force polling depending
on their type, but this may generate system load without real benefits
for typical use which is NFS mounted home directories as in 99% of the
changes the user is interested to see are the ones done locally in the
session, and the fact that remote changes may be discovered only later
asynchronously is not a problem. Maybe a mix of polling and dnotify would
be the best strategy but I'm afraid of the code implications of such an
implementation :-)

Daniel

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