[PATCH v2 00/16] block atomic writes

[Christoph Hellwig]

On Tue, Dec 19, 2023 at 12:41:37PM +0000, John Garry wrote:
> How about something based on fcntl, like below? We will prob also require 
> some per-FS flag for enabling atomic writes without HW support. That flag 
> might be also useful for XFS for differentiating forcealign for atomic 
> writes with just forcealign.

I would have just exposed it through a user visible flag instead of
adding yet another ioctl/fcntl opcode and yet another method.

And yes, for anything that doesn't always support atomic writes it would
need to be persisted.