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

John Garry
2023-12-19T16:53:59Z

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

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.