Re: [PATCH v6 10/13] xfs: iomap COW-based atomic write support

From: John Garry
Date: Mon Mar 17 2025 - 10:58:39 EST


On 17/03/2025 14:20, Ritesh Harjani (IBM) wrote:
And, as mentioned earlier, it is ok to use REQ_ATOMIC method on an
unwritten extent.

I am guessing this is kept intentional?

Yes
Thanks, John for addressing the queries. It would be helpful to include
this information in the commit message as well then right? Otherwise
IMO, the original commit message looks incomplete.

ok, fine. I am just worried that these commit messages become too wordy. But, if people want this info, then I can provide it.


Maybe we can add this too?
=========================
This patch adds CoW based atomic write support which will be used as a
SW fallback in following scenarios:

- All append write scenarios.
- Any new writes on the region containing holes.

but only for > 1x block.

if we must be able to alloc at least a block :)

- Writes to any misaligned regions
- Writes to discontiguous extents.

ok, fine



<original commit msg snip>
=========================
In cases of an atomic write covering misaligned or discontiguous disk
blocks, we will use a CoW-based method to issue the atomic write.

sure

Thanks,
John