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). -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
