On Tue, 2008-09-02 at 17:02 -0400, Christoph Hellwig wrote: > On Tue, Sep 02, 2008 at 11:09:54AM -0600, Andreas Dilger wrote: > > The fsid is supposed to be a persistent, unique identifier for the > > filesystem, used by NFS in file handles. Using st_dev is unsafe, > > because that may change from one server boot to the next, because > > of device probing order, driver changes, etc. Also, not all filesystems > > HAVE a valid st_dev in the first place, which is the whole reason > > for this thread. > > > > I think a ->get_fsid() export method would be preferable. > > Umm, different things. f_fsid in stat(v)fs is just a cookie exported to > userspac that has never really been documented. > > We also called the filesystem part of the NFS filehandle in a few > places, and for those it's correct that it should be stable. Currently > the fsid is either created from the dev_t in kernelspace or from > uuids extracted through libuuid in userspace. Or from the f_fsid returned in statfs(), as of a week or so ago. > I can't see anything in the message that started this thread that > mentions NFS, btw. That was Artem's motivation for filling in f_fsid in the first place. Does anything else even _care_ about f_fsid? -- David Woodhouse Open Source Technology Centre David.Woodhouse@xxxxxxxxx Intel Corporation -- 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
