On Tue, Mar 1, 2011 at 12:07 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote: > On Mon, Feb 28, 2011 at 10:28:08PM -0500, J. Bruce Fields wrote: >> On Mon, Feb 28, 2011 at 08:33:08PM -0600, Steve French wrote: >> > On Mon, Feb 28, 2011 at 5:59 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote: >> > > On Mon, Feb 28, 2011 at 05:52:09PM -0600, Steve French wrote: >> > >> On Mon, Feb 28, 2011 at 5:42 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote: >> > >> > OK. Then as things stand we're stuck returning ESTALE to the client >> > >> > unless we happen to have the inode they're looking for in our cache? >> > >> >> > >> Yes - that seems right and consistent with what I remember other file >> > >> systems doing. >> > > >> > > No, other filesystems are able to look up the file on disk by inode >> > > number (or by whatever identifier they use in the filehandle). They >> > > don't depend on already having the inode in core. >> > >> > Grepping for ESTALE looks like there are dozens of places in various >> > fs where ESTALE can get returned ... >> >> Certainly true. >> >> But they do have to be able to look up any inode, regardless of whether >> it is currently in cache. >> >> Otherwise applications on the client would see ESTALE after any server >> reboot, or any time an inode was forced out of cache (for whatever >> reason). >> >> That would be quite painful. > > So if my understanding of the cifs behavior here is correct, then I > don't believe nfs exports of cifs will be usable. > > In the long term perhaps it could be possible with changes to one or the > other of the protocols: for example, perhaps future versions of the nfs > protocol could be made less reliant on long-lived filehandles. But that > would be a major change. > > --b. > Bruce, I am not getting a picture of how NFS server would return ESTALE error to nfs client and then on to the app for a filehandle fragment that happens to be coded as uniqueid by cifs during encode_fh if inode with that uniqueid does not happen to exist in vfs cache on the server box. When nfs passes down filehandle fragment (uniqueid) to cifs in fh_to_dentry, if the inode does not exist in cache, cifs will pick a new inode and copy this uniqueid as inode number. Not sure what happens next for nfs server to sense a stale file(handle fragment). -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
