Re: [PATCH v3 0/3] io_uring getdents

[Hao Xu <hao.xu@linux.dev>]

On 7/12/23 07:47, Dave Chinner wrote:
> On Tue, Jul 11, 2023 at 07:40:24PM +0800, Hao Xu wrote:
>> From: Hao Xu <howeyxu@tencent.com>
>>
>> This series introduce getdents64 to io_uring, the code logic is similar
>> with the snychronized version's. It first try nowait issue, and offload
>> it to io-wq threads if the first try fails.
>>
>>
>> v2->v3:
>>   - removed the kernfs patches
>>   - add f_pos_lock logic
>>   - remove the "reduce last EOF getdents try" optimization since
>>     Dominique reports that doesn't make difference
>>   - remove the rewind logic, I think the right way is to introduce lseek
>>     to io_uring not to patch this logic to getdents.
>>   - add Singed-off-by of Stefan Roesch for patch 1 since checkpatch
>>     complained that Co-developed-by someone should be accompanied with
>>     Signed-off-by same person, I can remove them if Stefan thinks that's
>>     not proper.
>>
>>
>> Dominique Martinet (1):
>>    fs: split off vfs_getdents function of getdents64 syscall
>>
>> Hao Xu (2):
>>    vfs_getdents/struct dir_context: add flags field
>>    io_uring: add support for getdents
> 
> So what filesystem actually uses this new NOWAIT functionality?
> Unless I'm blind (quite possibly) I don't see any filesystem
> implementation of this functionality in the patch series.
> 
> I know I posted a prototype for XFS to use it, and I expected that
> it would become part of this patch series to avoid the "we don't add
> unused code to the kernel" problem. i.e. the authors would take the
> XFS prototype, make it work, add support into for the new io_uring
> operation to fsstress in fstests and then use that to stress test
> the new infrastructure before it gets merged....
> 
> But I don't see any of this?
> 
> -Dave.

Hi Dave,
You are right, currently no real filesystem supports that from my 
investigation, I saw the xfs prototype, I'd like to make it work first.
That may cause some time.

Thanks,
Hao