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Date: Tue, 19 Dec 2023 16:53:27 +0000
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Subject: Re: [PATCH v2 00/16] block atomic writes
To: Christoph Hellwig <hch@lst.de>
Cc: "Darrick J. Wong" <djwong@kernel.org>, axboe@kernel.dk, kbusch@kernel.org,
        sagi@grimberg.me, jejb@linux.ibm.com, martin.petersen@oracle.com,
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From: John Garry <john.g.garry@oracle.com>
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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.