# Re: \[PATCH v2 0/5\] fs, xfs: block map immutable files for dax, dma-to-storage, and swap

- From: Christoph Hellwig \<hidden\>
- Date: 2017-08-12 07:34:27 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2017/08/125088
- Thread: https://ratatoskr.run/linux-xfs/2017/08/125097/t.md

```text
On Fri, Aug 11, 2017 at 08:57:18PM -0700, Andy Lutomirski wrote:
> One thing that makes me quite nervous about S_IOMAP_IMMUTABLE is the
> degree to which things go badly if one program relies on it while
> another program clears the flag: you risk corrupting unrelated
> filesystem metadata.  I think a userspace interface to pin the extent
> mapping of a file really wants a way to reliably keep it pinned (or to
> reliably zap the userspace application if it gets unpinned).

The nice thing is that no application can rely on it anyway..
```