On Sat, Jun 30, 2012 at 12:04:36AM -0700, Tejun Heo wrote:
> Hello, Al.
>
> On Fri, Jun 29, 2012 at 11:47 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> > On Sat, Jun 30, 2012 at 02:13:02PM +0800, Li Zefan wrote:
> >> So it's bad to have dentry refcnts dangling after umount.
> >
> > No shit. ?Yes, it is bad. ?What on the Earth is cgroup code doing with
> > those? ?And what could it possibly want to do with dentry reference
> > after the filesystem has been shut down, assuming it could hold one
> > in the first place?
>
> cgroup interface code was copied from sysfs back when it was
> piggybacking internal data structures to dentries, so, unfortunately,
> sysfs is still using dentries to manage internal data structures and
> propagates internal refs to dentry refs. There seem to be several
> places where dentry ref is held w/o active super ref triggering BUG on
> umount. Longer term, it should be updated to share sysfs code, I
> guess.
Now that I've looked at that code again... What's the story with
simple_unlink(d->d_inode, d);
in cgroup_rm_file()? Wrong parent inode, at the very least...
While we are at it, what the hell is going on in
static void cgroup_clear_directory(struct dentry *dir)
{
struct cgroup *cgrp = __d_cgrp(dir);
while (!list_empty(&cgrp->files))
cgroup_rm_file(cgrp, NULL);
}
Are you fighting some kind of race against somebody adding stuff
there? Unless I'm seriously misreading cgroup_rm_file(), it'll
do all the work on the first call...
--
To unsubscribe from this list: send the line "unsubscribe cgroups" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
