Re: [PATCH] f2fs: do not support mmap write for large folio

From: David Hildenbrand (Arm)

Date: Wed Apr 08 2026 - 10:07:41 EST


On 4/8/26 07:03, Christoph Hellwig wrote:
> On Tue, Apr 07, 2026 at 10:58:11PM +0000, Jaegeuk Kim wrote:
>> On 04/06, Christoph Hellwig wrote:
>>>
>>> Why? And how is this not breaking applications?
>>
>> Since we only support the large folio on the read case.
>
> In general spelling such basic out in the commit log, and even comments
> is really helpful. I'm curious how this works, though - by the time
> you read a large folio you don't know if it will ever be written to.

Why are only large folios supported for read?

Where is that allocation logic and how can that path even be triggered?

Also, usually we check for large folios by testing the actual folio, not
whether the mapping supports them?

--
Cheers,

David