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

Christoph Hellwig
2023-12-21T06:50:41Z

On Tue, Dec 19, 2023 at 04:53:27PM +0000, John Garry wrote:
> 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.

I'd be fine with that, but we're kinda running out of flag there.
That's why I suggested the FS_XFLAG_ instead, which basically works
the same.