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-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
