Re: [PATCH 2/4] fs: remove the never implemented aio_fsync file operation

[Christoph Hellwig]

On Tue, Nov 01, 2016 at 07:25:21AM +1100, Dave Chinner wrote:
> That sounds like a problem with your fix - it should work
> regardless of whether a valid/implemented AIO function is called
> or not, right? There's no difference between an invalid command,
> IOCB_CMD_FSYNC where ->aio_fsync() is null, or some supported
> command that immediately returns -EIO, the end result should
> be the same...

We would need the same increased file refcount if aio_fsync actually
was implemented using -EIOCBQUEUED returns.  We wouldn't nessecarily need
it without that.

> > I'm not going to complain about a proper implementation, but right now
> > we don't have any, and I'm not even sure the method signature is
> > all that suitable.  E.g. for the in-kernel users we'd really want a 
> > ranged fsync like the normal fsync anyway.
> 
> You mean like this version I posted a year ago:
> 
> https://lkml.org/lkml/2015/10/29/517

I'd love to see that one in - but it doesn't use the aio_fsync method
either..