* [PATCH] io_uring: don't set REQ_F_NOWAIT for regular files opend O_NONBLOCK
@ 2020-05-29 7:18 Jiufei Xue
2020-05-29 14:20 ` Jens Axboe
0 siblings, 1 reply; 4+ messages in thread
From: Jiufei Xue @ 2020-05-29 7:18 UTC (permalink / raw)
To: io-uring; +Cc: axboe, joseph.qi
When read from a regular file that was opened O_NONBLOCK, it will
return EAGAIN if the page is not cached, which is not expected and
fails the application.
Applications written before expect that the open flag O_NONBLOCK has
no effect on a regular file.
Fix this by not setting REQ_F_NOWAIT for regular files.
Signed-off-by: Jiufei Xue <[email protected]>
---
fs/io_uring.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 95df63b..69db8bb 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2107,7 +2107,7 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
/* don't allow async punt if RWF_NOWAIT was requested */
if ((kiocb->ki_flags & IOCB_NOWAIT) ||
- (req->file->f_flags & O_NONBLOCK))
+ (!(req->flags & REQ_F_ISREG) && (req->file->f_flags & O_NONBLOCK)))
req->flags |= REQ_F_NOWAIT;
if (force_nonblock)
--
1.8.3.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] io_uring: don't set REQ_F_NOWAIT for regular files opend O_NONBLOCK
2020-05-29 7:18 [PATCH] io_uring: don't set REQ_F_NOWAIT for regular files opend O_NONBLOCK Jiufei Xue
@ 2020-05-29 14:20 ` Jens Axboe
2020-06-01 3:26 ` Jiufei Xue
0 siblings, 1 reply; 4+ messages in thread
From: Jens Axboe @ 2020-05-29 14:20 UTC (permalink / raw)
To: Jiufei Xue, io-uring; +Cc: joseph.qi
On 5/29/20 1:18 AM, Jiufei Xue wrote:
> When read from a regular file that was opened O_NONBLOCK, it will
> return EAGAIN if the page is not cached, which is not expected and
> fails the application.
>
> Applications written before expect that the open flag O_NONBLOCK has
> no effect on a regular file.
>
> Fix this by not setting REQ_F_NOWAIT for regular files.
Agree, this also matches what we do for sockets. You need to update
the comment as well, though.
--
Jens Axboe
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] io_uring: don't set REQ_F_NOWAIT for regular files opend O_NONBLOCK
2020-05-29 14:20 ` Jens Axboe
@ 2020-06-01 3:26 ` Jiufei Xue
2020-06-10 6:16 ` Jiufei Xue
0 siblings, 1 reply; 4+ messages in thread
From: Jiufei Xue @ 2020-06-01 3:26 UTC (permalink / raw)
To: Jens Axboe, io-uring; +Cc: joseph.qi
Hi Jens,
On 2020/5/29 下午10:20, Jens Axboe wrote:
> On 5/29/20 1:18 AM, Jiufei Xue wrote:
>> When read from a regular file that was opened O_NONBLOCK, it will
>> return EAGAIN if the page is not cached, which is not expected and
>> fails the application.
>>
>> Applications written before expect that the open flag O_NONBLOCK has
>> no effect on a regular file.
>>
>> Fix this by not setting REQ_F_NOWAIT for regular files.
>
> Agree, this also matches what we do for sockets. You need to update
> the comment as well, though.
>
Reading from an O_NONBLOCK socket will return EAGAIN if there isn't any
unread data in the buffer which is expected.So I don't know what is your
meaning about that. Do you mean the recv() interface?
Regards,
Jiufei
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] io_uring: don't set REQ_F_NOWAIT for regular files opend O_NONBLOCK
2020-06-01 3:26 ` Jiufei Xue
@ 2020-06-10 6:16 ` Jiufei Xue
0 siblings, 0 replies; 4+ messages in thread
From: Jiufei Xue @ 2020-06-10 6:16 UTC (permalink / raw)
To: Jens Axboe, io-uring; +Cc: joseph.qi
Hi Jens,
Could you please spent some time to look at this?
Thanks,
Jiufei
On 2020/6/1 上午11:26, Jiufei Xue wrote:
> Hi Jens,
>
> On 2020/5/29 下午10:20, Jens Axboe wrote:
>> On 5/29/20 1:18 AM, Jiufei Xue wrote:
>>> When read from a regular file that was opened O_NONBLOCK, it will
>>> return EAGAIN if the page is not cached, which is not expected and
>>> fails the application.
>>>
>>> Applications written before expect that the open flag O_NONBLOCK has
>>> no effect on a regular file.
>>>
>>> Fix this by not setting REQ_F_NOWAIT for regular files.
>>
>> Agree, this also matches what we do for sockets. You need to update
>> the comment as well, though.
>>
> Reading from an O_NONBLOCK socket will return EAGAIN if there isn't any
> unread data in the buffer which is expected.So I don't know what is your
> meaning about that. Do you mean the recv() interface?
>
> Regards,
> Jiufei
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-06-10 6:16 UTC | newest]
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2020-05-29 7:18 [PATCH] io_uring: don't set REQ_F_NOWAIT for regular files opend O_NONBLOCK Jiufei Xue
2020-05-29 14:20 ` Jens Axboe
2020-06-01 3:26 ` Jiufei Xue
2020-06-10 6:16 ` Jiufei Xue
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