Re: [PATCHSET RFC 0/6] add support for name_to, open_by_handle_at(2) to io_uring

["Thomas Bertschinger" <tahbertschinger@gmail.com>]

On Fri Aug 15, 2025 at 3:52 AM MDT, Amir Goldstein wrote:
> On Fri, Aug 15, 2025 at 1:50 AM Thomas Bertschinger
> <tahbertschinger@gmail.com> wrote:
>> No attempt is made to support a non-blocking open_by_handle_at()--the
>> attempt is always immediately returned with -EAGAIN if
>> IO_URING_F_NONBLOCK is set.
>>
>> This isn't ideal and it would be nice to add support for non-blocking
>> open by handle in the future. This would presumably require updates to
>> the ->encode_fh() implementation for filesystems that want to
>> support this.
>
> Correction: ->encode_fh() is for name_to_handle()
> You want to say that ->fh_to_dentry() need to support cached lookup,
Yes, that is what I meant, whoops.

> but FWIW, the blocking code is more likely to come from the
> lookup in exportfs_decode_fh_raw() => ... reconnect_one()
> not from the filesystem code.
>
> The fs would "only" need to be taught to return an alias to a
> cached inode and generic code would "only" need to be taught
> to give up on a disconnected dir dentry.
>
> Doesn't sound too hard (famous last words).
>
> Thanks,
> Amir.
>

Thanks for the ideas on how to support this!