[Virtio-fs] [PATCH 1/2] fuse: disable atomic_o_trunc if no_open is enabled

[JeffleXu]

On 9/7/21 4:34 PM, Miklos Szeredi wrote:
> On Thu, 12 Aug 2021 at 07:46, Jeffle Xu <jefflexu at linux.alibaba.com> wrote:
>>
>> From: Liu Bo <bo.liu at linux.alibaba.com>
>>
>> When 'no_open' is used by virtiofsd, guest kernel won't send OPEN request
>> any more.  However, with atomic_o_trunc, SETATTR request is also omitted in
>> OPEN(O_TRUNC) so that the backend file is not truncated.  With a following
>> GETATTR, inode size on guest side is updated to be same with that on host
>> side, the end result is that O_TRUNC semantic is broken.
>>
>> This disables atomic_o_trunc as well if with no_open.
> 
> I don't quite get it why one would want to enable atomic_o_trunc with
> no_open in the first place?

Oops..We didn't realize that it could also be worked around by fuse
daemon side. Please ignore this.

-- 
Thanks,
Jeffle