Re: [PATCH V4 07/13] fs: Add locking for a dynamic address space operations state

[Jeff Moyer]

Christoph Hellwig <hch@xxxxxx> writes:

> And my point is that if we ensure S_DAX can only be checked if there
> are no blocks on the file, is is fairly easy to provide the same
> guarantee.  And I've not heard any argument that we really need more
> flexibility than that.  In fact I think just being able to change it
> on the parent directory and inheriting the flag might be more than
> plenty, which would lead to a very simple implementation without any
> of the crazy overhead in this series.

I know of one user who had at least mentioned it to me, so I cc'd him.
Jonathan, can you describe your use case for being able to change a
file between dax and non-dax modes?  Or, if I'm misremembering, just
correct me?

Thanks!
Jeff