Re: [RFC v2 00/10] bdev: LBS devices support to coexist with buffer-heads

[Hannes Reinecke <hare@suse.de>]

On 9/18/23 20:15, Matthew Wilcox wrote:
> On Mon, Sep 18, 2023 at 10:12:04AM -0700, Luis Chamberlain wrote:
>> On Fri, Sep 15, 2023 at 10:51:12PM +0100, Matthew Wilcox wrote:
>>> On Fri, Sep 15, 2023 at 02:32:44PM -0700, Luis Chamberlain wrote:
>>>> However, an issue is that disabling CONFIG_BUFFER_HEAD in practice is not viable
>>>> for many Linux distributions since it also means disabling support for most
>>>> filesystems other than btrfs and XFS. So we either support larger order folios
>>>> on buffer-heads, or we draw up a solution to enable co-existence. Since at LSFMM
>>>> 2023 it was decided we would not support larger order folios on buffer-heads,
>>>
>>> Um, I didn't agree to that.
>>
>> Coverage on sunsetting buffer-heads talk by LWN:
>>
>> https://lwn.net/Articles/931809/
>>
>> "the apparent conclusion from the session: the buffer-head layer will be
>> converted to use folios internally while minimizing changes visible to
>> the filesystems using it. Only single-page folios will be used within
>> this new buffer-head layer. Any other desires, he said, can be addressed
>> later after this problem has been solved."
> 
> Other people said that.  Not me.  I said it was fine for single
> buffer_head per folio.

And my patchset proves that to be the case.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Ivo Totev, Andrew
Myers, Andrew McDonald, Martje Boudien Moerman