lkml.org 
[lkml]   [2007]   [Oct]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: Networked filesystems vs backing_dev_info
From
Date

On Sat, 2007-10-27 at 11:22 -0400, Jan Harkes wrote:
> On Sat, Oct 27, 2007 at 11:34:26AM +0200, Peter Zijlstra wrote:
> > I had me a little look at bdi usage in networked filesystems.
> >
> > NFS, CIFS, (smbfs), AFS, CODA and NCP
> >
> > And of those, NFS is the only one that I could find that creates
> > backing_dev_info structures. The rest seems to fall back to
> > default_backing_dev_info.
>
> While a file is opened in Coda we associate the open file handle with a
> local cache file. All read and write operations are redirected to this
> local file and we even redirect inode->i_mapping. Actual reads and
> writes are completely handled by the underlying file system. We send the
> new file contents back to the servers only after all local references
> have been released (last-close semantics).
>
> As a result, there is no need for backing_dev_info structures in Coda,
> if any congestion control is needed it will be handled by the underlying
> file system where our locally cached copies are stored.

Ok, that works. Thanks for this explanation!

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-10-27 17:35    [from the cache]
©2003-2011 Jasper Spaans