Re: iomap infrastructure and multipage writes V4

Verma, Vishal L
2016-05-11T22:42:47Z

On Mon, 2016-05-09 at 10:47 +0200, Christoph Hellwig wrote:
> This series add a new file system I/O path that uses the iomap
> structure
> introduced for the pNFS support and support multi-page buffered
> writes.
>
> This was first started by Dave Chinner a long time ago, then I did
> beat
> it into shape for production runs in a very constrained ARM NAS
> enviroment for Tuxera almost as long ago, and now half a dozen
> rewrites
> later it's back.
>
> The basic idea is to avoid the per-block get_blocks overhead
> and make use of extents in the buffered write path by iterating over
> them instead.
>
> Note that patch 1 conflicts with Vishals dax error handling series.
> It would be great to have a stable branch with it so that both the
> XFS and nvdimm tree could pull it in before the other changes in this
> area.

I'm looking to post a stable branch with my patches soon. My patches
depend on Jan's fixes for ext4 and DAX, and as soon as they land in a
stable ext4 branch, I'll create one for dax error handling. In the
meanwhile, v7 of my patches includes your patch 1 updated for the error
handling series.

>
> Changes since V3:
>  - fix DAX based zeroing
>  - Reviews and trivial fixes from Bob
>
> Changes since V2:
>  - fix the range for delalloc punches after failed writes
>  - updated some changelogs
>
> Chances since V1:
>  - add support for fiemap
>  - fix a test fail on 1k block sizes
>  - prepare for 64-bit length, this will be used in a follow on
> patchset
>