Re: [PATCH v2 00/16] block atomic writes

On 19/12/2023 15:17, Christoph Hellwig wrote:

On Tue, Dec 19, 2023 at 12:41:37PM +0000, John Garry wrote:

quoted

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.

Any specific type of flag?

I would suggest a file attribute which we can set via chattr, but that is still using an ioctl and would require a new inode flag; but at least there is standard userspace support.

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