Re: NFS client llseek

[Jan Harkes <jaharkes@cs.cmu.edu>]

On Fri, Dec 14, 2001 at 01:51:36PM +0100, Trond Myklebust wrote:
> Just one comment: Isn't it easier to do this in generic_file_llseek()
> itself using inode->i_op->revalidate()? That would make it work for
> coda and smbfs too...

Actually, as far as Coda is concerned this only adds overhead. Coda uses
AFS2 session semantics instead of UNIX semantics, so updates are only
propagated when a file is closed.

Adding this to the generic_file_llseek will force an useless but
expensive upcall (and RPC call to the server) to every seek to check for
an updated i_size while we already know that the i_size of the file
won't have to change until it is closed and reopened.

I guess we're just (mis-)using the revalidate call as a replacement of a
missing call to i_ops->getattr from sys_stat. So perhaps adding the
revalidate to the generic_llseek is fine, but I'll just have to get that
missing getattr call into the tree.

Jan