Re: LTP write03 writev07 xfs failures

[Christoph Hellwig]

On Tue, Feb 28, 2017 at 09:59:40AM -0500, Brian Foster wrote:
> Heh. I've appended what I'm currently playing around with. It's
> certainly uglier, but not terrible IMO (outside of the fact that we have
> to look at the buffer_heads). This seems to address the problem, but
> still only lightly tested...
> 
> An entirely different approach may be to somehow or another
> differentiate allocated delalloc blocks from "found" delalloc blocks in
> the iomap_begin() handler, and then perhaps encode that into the iomap
> such that the iomap_end() handler has an explicit reference of what to
> punch. Personally, I wouldn't mind doing something like the below short
> term to fix the regression and then incorporate an iomap enhancement to
> break the buffer_head dependency.

We actually have a IOMAP_F_NEW for this already, but so far it's
only used by the DIO and DAX code.