On Tue, 2012-07-10 at 04:10 +0900, OGAWA Hirofumi wrote: > "Steven J. Magnani" <st...@digidescorp.com> writes: > > >> > >> > Interesting idea. I think this, and reformulating the FAT NFS file > >> > >> > handle to include the parent's i_ino, will greatly simplify (and > >> > >> > speed > >> > >> > up) the code. > >> > >> > >> > >> Does it work even if the inode was rename()'ed? > >> > > > >> > > AFAICT. I don't see why it wouldn't; on a rename, the inode's i_pos > >> > > changes but its i_ino stays the same, right? > >> > > >> > If the inode is not on cache anymore, is there the possibility that > >> > selects the wrong parent? IIRC, NFS Server can be rebooted at any time > >> > while the client using the same file handle. > >> > >> True, but it's looking like we can just use the default handle > >> constructed by export_encode_fh(), namely (i_ino, i_generation, > >> parent->i_ino, parent->i_generation). None of those components should > >> change in a server reboot. > > > > I think I misunderstood you when I wrote this. I assumed we were talking > > about a restart of nfsd, not the entire machine it was running on. If > > there is a danger of mismapping on a reboot isn't that present in the > > existing mainline code, i.e. fat_fh_to_dentry()? Ideally, the (i_ino, > > i_generation) signature would be different on a reboot, although with > > only 2-second granularity in i_generation I suppose that's less likely > > than we would prefer. Also I would think that many inodes simply > > wouldn't exist in the cache, in which case we would fail the operation > > with ESTALE. > > Ah, i_ino. I was talking about i_pos. Well, so, what happens if the > child was renamed to other parent on NFS server machine (not via nfs > client)? The file handle would be including the old i_ino, and the old > i_ino on file handle is still vaild as old parent. So, it returns the > wrong parent?
Yes, but I believe exportfs_decode_fh() handles that case: /* * Now that we've got both a well-connected parent and a * dentry for the inode we're after, make sure that our * inode is actually connected to the parent. */ Really, the FAT NFS code will pretty much parallel that of ext2. ------------------------------------------------------------------------ Steven J. Magnani "I claim this network for MARS! www.digidescorp.com Earthling, return my space modulator!" #include <standard.disclaimer> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
