On Thu, 2011-01-27 at 11:44 +1100, Nick Piggin wrote: > On Thu, Jan 27, 2011 at 10:59 AM, Trond Myklebust > <Trond.Myklebust@xxxxxxxxxx> wrote: > > On Thu, 2011-01-27 at 10:50 +1100, Nick Piggin wrote: > >> On Thu, Jan 27, 2011 at 7:43 AM, Trond Myklebust > >> <Trond.Myklebust@xxxxxxxxxx> wrote: > >> > On Wed, 2011-01-26 at 15:14 -0500, Trond Myklebust wrote: > >> >> The alternative would be to add a callback that can be called after > >> >> dentry_iput() if DCACHE_NFSFS_RENAMED is true, and that takes the parent > >> >> and (negative) dentry as the arguments. > >> >> sillyrename doesn't need the inode as an argument, but it definitely > >> >> needs the parent dentry so that it can check for races with > >> >> ->lookup()... > >> > > >> > The following (compile tested only!) patch illustrates what I mean. > >> > >> We could do this. CEPH also want a way to get d_parent in the inode > >> unlink path. > >> > >> I think I can actually check for dentry->d_count == 0 rather than > >> dentry->d_parent == NULL here, and avoid clearing d_parent > >> entirely. That might be the better solution for 2.6.38, because other > >> code I've missed might be expecting to use d_parent. > > > > I'm not sure I understand. By the time we hit d_kill() we know that > > dentry->d_count == 0. > > The dcache patch to set d_parent to NULL was done so that when > walking the other way up the path we can check that the parent is > still valid. > > But we could just check for d_count != 0 which means the parent has > to be valid as well (we have rename protection as well). That would certainly be less intrusive. Can you please propose a patch? Cheers Trond -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@xxxxxxxxxx www.netapp.com -- 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
