Re: [RFC 0/7] ext4: Allocator changes for atomic write support with DIO

[Theodore Ts'o]

On Tue, Dec 12, 2023 at 05:10:42AM -0800, Christoph Hellwig wrote:
> On Tue, Dec 12, 2023 at 07:46:51AM +0000, John Garry wrote:
> > It is assumed that the user will fallocate/dd the complete file before
> > issuing atomic writes, and we will have extent alignment and length as
> > required.
> 
> I don't think that's a long time maintainable usage model.

For databases that are trying to use this to significantly improve
their performance by eliminating double writes, the allocation and
writes are being done by a single process.  So for *that* use case, it
is quite maintainable.

Cheers,

						- Ted