On Tue, Sep 25, 2012 at 04:29:58AM -0700, Eric W. Biederman wrote: > Maarten Lankhorst <[email protected]> writes: > > >> Could you try the following patch? This should report what directories > >> cannot be renamed because one of them is a mount point and it gives some > >> real insight into what is going on. > > > > ls / > > __d_unalias: /dev -> /dev > > __d_unalias: /proc -> /proc > > __d_unalias: /sys -> /sys > > Ok. That is what I thought was going on. For some reason nfs is > attempting to recreate an existing dentry. > > Does this fix the nfs problem for you? > > Eric > > diff --git a/fs/dcache.c b/fs/dcache.c > index 8086636..6390f0f 100644 > --- a/fs/dcache.c > +++ b/fs/dcache.c > @@ -2404,6 +2404,9 @@ out_unalias: > if (likely(!d_mountpoint(alias))) { > __d_move(alias, dentry); > ret = alias; > + } else if ((alias->d_parent == dentry->d_parent) && > + !dentry_cmp(alias, dentry->d_name.name, dentry->d_name.len)) > + ret = alias; > }
The interesting question is why the hell had it decided that preexisting dentry was not good enough for it? Note that we have arrived to nfs_lookup() after we'd decided *not* to use the damn alias. The trace posted upthread went __lookup_hash() -> lookup_real(). It means that lookup_dcache() has not produced this one. And no, even if ->d_revalidate() decided it was no good, the logics in d_invalidate() would've said "busy" and we'd gone with that dentry anyway. So it means that d_lookup() has not found it at all. IOW, something out there is blindly unhashing mountpoint dentries; that's where the real root of the problem seems to be. Could you slap WARN_ON(d_mountpoint(dentry)) in __d_drop() and see what it catches? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
