Re: [RFC PATCH 0/8] xfs: single block atomic writes for buffered IO

Ritesh Harjani
2025-11-13T05:53:57Z

Christoph Hellwig <hch@lst.de> writes:

> On Thu, Nov 13, 2025 at 08:56:56AM +1100, Dave Chinner wrote:
>> On Wed, Nov 12, 2025 at 04:36:03PM +0530, Ojaswin Mujoo wrote:
>> > This patch adds support to perform single block RWF_ATOMIC writes for
>> > iomap xfs buffered IO. This builds upon the inital RFC shared by John
>> > Garry last year [1]. Most of the details are present in the respective
>> > commit messages but I'd mention some of the design points below:
>>
>> What is the use case for this functionality? i.e. what is the
>> reason for adding all this complexity?
>
> Seconded. The atomic code has a lot of complexity, and further mixing
> it with buffered I/O makes this even worse. We'd need a really important
> use case to even consider it.

I agree this should have been in the cover letter itself.

I believe the reason for adding this functionality was also discussed at
LSFMM too...

For e.g. https://lwn.net/Articles/974578/ goes in depth and talks about
Postgres folks looking for this, since PostgreSQL databases uses
buffered I/O for their database writes.

-ritesh