# Re: \[PATCH 4/7\] proc: Use d\_invalidate in proc\_prune\_siblings\_dcache

- From: Al Viro \<viro@zeniv.linux.org.uk\>
- Date: 2020-02-20 23:03:20 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2020/02/173456
- Thread: https://ratatoskr.run/linux-api/2020/02/173442/t.md

```text
On Thu, Feb 20, 2020 at 10:54:20PM +0000, Al Viro wrote:
> On Thu, Feb 20, 2020 at 02:49:53PM -0600, Eric W. Biederman wrote:
> > 
> > The function d_prune_aliases has the problem that it will only prune
> > aliases thare are completely unused.  It will not remove aliases for
> > the dcache or even think of removing mounts from the dcache.  For that
> > behavior d_invalidate is needed.
> > 
> > To use d_invalidate replace d_prune_aliases with d_find_alias
> > followed by d_invalidate and dput.  This is safe and complete
> > because no inode in proc has any hardlinks or aliases.
> 
> s/no inode.*/it's a fucking directory inode./

Wait... You are using it for sysctls as well?  Ho-hum...  The thing is,
for sysctls you are likely to run into consequent entries with the
same superblock, making for a big pile of useless playing with
->s_active...  And yes, that applied to mainline as well
```