On Thu, Feb 13, 2014 at 03:45:16PM -0800, Eric W. Biederman wrote:
> "J. Bruce Fields" <bfields@xxxxxxxxxxxx> writes:
>
> > Yesterday you passed on a report of this printk from nfsdfh.c firing:
> >
> > printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %pd2\n",
> > dentry);
> >
> > I think the dentry probably comes from the FILEID_ROOT case of:
> >
> > if (fileid_type == FILEID_ROOT)
> > dentry = dget(exp->ex_path.dentry);
> > else {
> > dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
> > data_left, fileid_type,
> > nfsd_acceptable, exp);
> > }
> >
> > In that case the dentry was found using ordinary filesystem lookups, so
> > doesn't go through the same DISCONNECTED-clearing logic as in the case
> > of lookups by filehandle.
> >
> > Probably they have an export root that's not a filesystem root, and the
> > lookups happened in the right order?
> >
> > I suspect that's fine, and that the printk is just stupid, but maybe we
> > should clear DISCONNECTED when possible on normal lookups. The
> > following is my attempt, though I'm not sure if d_alloc is the right
> > place to do this. In any case it might help confirm this is what's
> > happening.
> >
> > So if you pass along this patch to the person who was seeing that printk
> > I'd be interested in the results.
>
> I have been reading through the dentry code for other reasons and your
> patch definitely won't change anything. __d_alloc sets d_flags = 0.
> Therefore d_alloc always returns with d_flags == 0.
You're right, of course. I wasn't thinking straight.
So the only dentries with DISCONNECTED set are those created with
d_obtain_alias, which is normally only used when you're looking up by
filehandle.
Except btrfs has a weird use in get_default_root(). So maybe they were
running into the dentry that created?
So btrfs should probably be using something else, I'm not sure what.
--b.
--
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
