f2fs: support uncached buffered I/O

[RFC PATCH 0/2] f2fs: support uncached buffered I/O

Posted by Wenjie Qi 1 month, 3 weeks ago

This RFC series enables buffered RWF_DONTCACHE on F2FS.

The first patch keeps dropbehind folios in dropbehind-only write bios and
defers their completion to task context when completion happens outside
in_task().

The second patch then exposes FOP_DONTCACHE and propagates
IOCB_DONTCACHE to write_begin folio allocation so buffered
RWF_DONTCACHE can reach the F2FS write path.

The split keeps the write-side semantics in place before enabling the
user-visible API.

Wenjie Qi (2):
  f2fs: keep dropbehind write bios task-context safe
  f2fs: enable buffered RWF_DONTCACHE

 fs/f2fs/data.c | 63 +++++++++++++++++++++++++++++++++++++++-----------
 fs/f2fs/file.c |  2 +-
 2 files changed, 51 insertions(+), 14 deletions(-)

-- 
2.43.0

Re: [RFC PATCH 0/2] f2fs: support uncached buffered I/O

Posted by Chao Yu 1 month, 2 weeks ago

On 8/6/26 23:07, Wenjie Qi wrote:
> This RFC series enables buffered RWF_DONTCACHE on F2FS.
> 
> The first patch keeps dropbehind folios in dropbehind-only write bios and
> defers their completion to task context when completion happens outside
> in_task().
> 
> The second patch then exposes FOP_DONTCACHE and propagates
> IOCB_DONTCACHE to write_begin folio allocation so buffered
> RWF_DONTCACHE can reach the F2FS write path.
> 
> The split keeps the write-side semantics in place before enabling the
> user-visible API.

Thanks for the patchset.

Do you have some numbers in device? maybe something like Han Qi did in
https://lore.kernel.org/linux-f2fs-devel/20250828121131.3694154-1-hanqi@vivo.com?

Thanks,

> 
> Wenjie Qi (2):
>    f2fs: keep dropbehind write bios task-context safe
>    f2fs: enable buffered RWF_DONTCACHE
> 
>   fs/f2fs/data.c | 63 +++++++++++++++++++++++++++++++++++++++-----------
>   fs/f2fs/file.c |  2 +-
>   2 files changed, 51 insertions(+), 14 deletions(-)
>