On Fri, 2008-08-15 at 10:18 -0400, Trond Myklebust wrote: > On Fri, 2008-08-15 at 14:59 +0100, David Woodhouse wrote: > > On Fri, 2008-08-15 at 11:55 +0300, Artem Bityutskiy wrote: > > > UBIFS (as e.g. XFS) has a 16-byte UUID in superblock which is > > > supposed to uniquely identify the file-system. I'd like to use > > > this UUID as NFS FSID instead, however, I failed to find how > > > to do this. Any hints how could I do this? > > > > By adding a 'get_fsid()' method to the export_ops structure... That approach is painful -- it's simple enough to make the export work, and it returns an appropriate root fh -- but then falls over immediately when the client gives that fh back to us in an FSINFO request and userspace mountd doesn't understand it. A hack to prepopulate the svc_export_cache too 'fixes' it, but won't survive reboots. > If the uuid can be found by libuuid, then it will automatically be used > as the default identifier by rpc.mount (man 5 exports). There should be > no need for a new export_ops method. The problem with libuuid is that it assumes that there's a block device, and a 1:1 mapping between file system and block device. That often isn't true. However, there _is_ a f_fsid field in struct statfs64, which we could happily use if libuuid fails. See git.infradead.org/users/dwmw2/nfs-utils.git -- if the file system fills in f_fsid, that should be all that's needed. -- 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
