FAILED: patch "[PATCH] io_uring: fix up O_NONBLOCK handling for sockets" failed to apply to 5.3-stable tree

FAILED: patch "[PATCH] io_uring: fix up O_NONBLOCK handling for sockets" failed to apply to 5.3-stable tree

[gregkh]

The patch below does not apply to the 5.3-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 491381ce07ca57f68c49c79a8a43da5b60749e32 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 17 Oct 2019 09:20:46 -0600
Subject: [PATCH] io_uring: fix up O_NONBLOCK handling for sockets

We've got two issues with the non-regular file handling for non-blocking
IO:

1) We don't want to re-do a short read in full for a non-regular file,
   as we can't just read the data again.
2) For non-regular files that don't support non-blocking IO attempts,
   we need to punt to async context even if the file is opened as
   non-blocking. Otherwise the caller always gets -EAGAIN.

Add two new request flags to handle these cases. One is just a cache
of the inode S_ISREG() status, the other tells io_uring that we always
need to punt this request to async context, even if REQ_F_NOWAIT is set.

Cc: stable@vger.kernel.org
Reported-by: Hrvoje Zeba <zeba.hrvoje@gmail.com>
Tested-by: Hrvoje Zeba <zeba.hrvoje@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index d2cb277da2f4..b7d4085d6ffd 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -322,6 +322,8 @@ struct io_kiocb {
 #define REQ_F_FAIL_LINK		256	/* fail rest of links */
 #define REQ_F_SHADOW_DRAIN	512	/* link-drain shadow req */
 #define REQ_F_TIMEOUT		1024	/* timeout request */
+#define REQ_F_ISREG		2048	/* regular file */
+#define REQ_F_MUST_PUNT		4096	/* must be punted even for NONBLOCK */
 	u64			user_data;
 	u32			result;
 	u32			sequence;
@@ -914,26 +916,26 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
 	return ret;
 }
 
-static void kiocb_end_write(struct kiocb *kiocb)
+static void kiocb_end_write(struct io_kiocb *req)
 {
-	if (kiocb->ki_flags & IOCB_WRITE) {
-		struct inode *inode = file_inode(kiocb->ki_filp);
+	/*
+	 * Tell lockdep we inherited freeze protection from submission
+	 * thread.
+	 */
+	if (req->flags & REQ_F_ISREG) {
+		struct inode *inode = file_inode(req->file);
 
-		/*
-		 * Tell lockdep we inherited freeze protection from submission
-		 * thread.
-		 */
-		if (S_ISREG(inode->i_mode))
-			__sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
-		file_end_write(kiocb->ki_filp);
+		__sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
 	}
+	file_end_write(req->file);
 }
 
 static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
 {
 	struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
 
-	kiocb_end_write(kiocb);
+	if (kiocb->ki_flags & IOCB_WRITE)
+		kiocb_end_write(req);
 
 	if ((req->flags & REQ_F_LINK) && res != req->result)
 		req->flags |= REQ_F_FAIL_LINK;
@@ -945,7 +947,8 @@ static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
 {
 	struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
 
-	kiocb_end_write(kiocb);
+	if (kiocb->ki_flags & IOCB_WRITE)
+		kiocb_end_write(req);
 
 	if ((req->flags & REQ_F_LINK) && res != req->result)
 		req->flags |= REQ_F_FAIL_LINK;
@@ -1059,8 +1062,17 @@ static int io_prep_rw(struct io_kiocb *req, const struct sqe_submit *s,
 	if (!req->file)
 		return -EBADF;
 
-	if (force_nonblock && !io_file_supports_async(req->file))
-		force_nonblock = false;
+	if (S_ISREG(file_inode(req->file)->i_mode))
+		req->flags |= REQ_F_ISREG;
+
+	/*
+	 * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
+	 * we know to async punt it even if it was opened O_NONBLOCK
+	 */
+	if (force_nonblock && !io_file_supports_async(req->file)) {
+		req->flags |= REQ_F_MUST_PUNT;
+		return -EAGAIN;
+	}
 
 	kiocb->ki_pos = READ_ONCE(sqe->off);
 	kiocb->ki_flags = iocb_flags(kiocb->ki_filp);
@@ -1081,7 +1093,8 @@ static int io_prep_rw(struct io_kiocb *req, const struct sqe_submit *s,
 		return ret;
 
 	/* don't allow async punt if RWF_NOWAIT was requested */
-	if (kiocb->ki_flags & IOCB_NOWAIT)
+	if ((kiocb->ki_flags & IOCB_NOWAIT) ||
+	    (req->file->f_flags & O_NONBLOCK))
 		req->flags |= REQ_F_NOWAIT;
 
 	if (force_nonblock)
@@ -1382,7 +1395,9 @@ static int io_read(struct io_kiocb *req, const struct sqe_submit *s,
 		 * need async punt anyway, so it's more efficient to do it
 		 * here.
 		 */
-		if (force_nonblock && ret2 > 0 && ret2 < read_size)
+		if (force_nonblock && !(req->flags & REQ_F_NOWAIT) &&
+		    (req->flags & REQ_F_ISREG) &&
+		    ret2 > 0 && ret2 < read_size)
 			ret2 = -EAGAIN;
 		/* Catch -EAGAIN return for forced non-blocking submission */
 		if (!force_nonblock || ret2 != -EAGAIN) {
@@ -1447,7 +1462,7 @@ static int io_write(struct io_kiocb *req, const struct sqe_submit *s,
 		 * released so that it doesn't complain about the held lock when
 		 * we return to userspace.
 		 */
-		if (S_ISREG(file_inode(file)->i_mode)) {
+		if (req->flags & REQ_F_ISREG) {
 			__sb_start_write(file_inode(file)->i_sb,
 						SB_FREEZE_WRITE, true);
 			__sb_writers_release(file_inode(file)->i_sb,
@@ -2282,7 +2297,13 @@ static int __io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
 	int ret;
 
 	ret = __io_submit_sqe(ctx, req, s, force_nonblock);
-	if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) {
+
+	/*
+	 * We async punt it if the file wasn't marked NOWAIT, or if the file
+	 * doesn't support non-blocking read/write attempts
+	 */
+	if (ret == -EAGAIN && (!(req->flags & REQ_F_NOWAIT) ||
+	    (req->flags & REQ_F_MUST_PUNT))) {
 		struct io_uring_sqe *sqe_copy;
 
 		sqe_copy = kmemdup(s->sqe, sizeof(*sqe_copy), GFP_KERNEL);

Re: FAILED: patch "[PATCH] io_uring: fix up O_NONBLOCK handling for sockets" failed to apply to 5.3-stable tree

[Jens Axboe]

On 10/27/19 9:53 AM, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 5.3-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.

I can fix this up, but I probably need to see Sasha's queue first for
the io_uring patches. I need to base it against that.

-- 
Jens Axboe

Re: FAILED: patch "[PATCH] io_uring: fix up O_NONBLOCK handling for sockets" failed to apply to 5.3-stable tree

[Greg KH]

On Sun, Oct 27, 2019 at 12:58:14PM -0600, Jens Axboe wrote:
> On 10/27/19 9:53 AM, gregkh@linuxfoundation.org wrote:
> > 
> > The patch below does not apply to the 5.3-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> 
> I can fix this up, but I probably need to see Sasha's queue first for
> the io_uring patches. I need to base it against that.

Ok, wait for the next 5.3.y release in a few days and send stuff off of
that if you can.

thanks,

greg k-h

Re: FAILED: patch "[PATCH] io_uring: fix up O_NONBLOCK handling for sockets" failed to apply to 5.3-stable tree

[Jens Axboe]

On 10/27/19 2:00 PM, Greg KH wrote:
> On Sun, Oct 27, 2019 at 12:58:14PM -0600, Jens Axboe wrote:
>> On 10/27/19 9:53 AM, gregkh@linuxfoundation.org wrote:
>>>
>>> The patch below does not apply to the 5.3-stable tree.
>>> If someone wants it applied there, or to any other stable or longterm
>>> tree, then please email the backport, including the original git commit
>>> id to <stable@vger.kernel.org>.
>>
>> I can fix this up, but I probably need to see Sasha's queue first for
>> the io_uring patches. I need to base it against that.
> 
> Ok, wait for the next 5.3.y release in a few days and send stuff off of
> that if you can.

Is there no "current" or similar tree to work of off? Would be a shame
to miss the next one, especially since the newer fixes are already in.

If not, I'll just wait for the next one.

-- 
Jens Axboe

Re: FAILED: patch "[PATCH] io_uring: fix up O_NONBLOCK handling for sockets" failed to apply to 5.3-stable tree

[Greg KH]

On Sun, Oct 27, 2019 at 02:22:06PM -0600, Jens Axboe wrote:
> On 10/27/19 2:00 PM, Greg KH wrote:
> > On Sun, Oct 27, 2019 at 12:58:14PM -0600, Jens Axboe wrote:
> >> On 10/27/19 9:53 AM, gregkh@linuxfoundation.org wrote:
> >>>
> >>> The patch below does not apply to the 5.3-stable tree.
> >>> If someone wants it applied there, or to any other stable or longterm
> >>> tree, then please email the backport, including the original git commit
> >>> id to <stable@vger.kernel.org>.
> >>
> >> I can fix this up, but I probably need to see Sasha's queue first for
> >> the io_uring patches. I need to base it against that.
> > 
> > Ok, wait for the next 5.3.y release in a few days and send stuff off of
> > that if you can.
> 
> Is there no "current" or similar tree to work of off? Would be a shame
> to miss the next one, especially since the newer fixes are already in.

I'm about to push out the -rcs right now.  You can base off of that and
send me the patch and I'll add it, or just wait a few days, either is
fine.

thanks,

greg k-h

Re: FAILED: patch "[PATCH] io_uring: fix up O_NONBLOCK handling for sockets" failed to apply to 5.3-stable tree

[Jens Axboe]

On 10/27/19 2:26 PM, Greg KH wrote:
> On Sun, Oct 27, 2019 at 02:22:06PM -0600, Jens Axboe wrote:
>> On 10/27/19 2:00 PM, Greg KH wrote:
>>> On Sun, Oct 27, 2019 at 12:58:14PM -0600, Jens Axboe wrote:
>>>> On 10/27/19 9:53 AM, gregkh@linuxfoundation.org wrote:
>>>>>
>>>>> The patch below does not apply to the 5.3-stable tree.
>>>>> If someone wants it applied there, or to any other stable or longterm
>>>>> tree, then please email the backport, including the original git commit
>>>>> id to <stable@vger.kernel.org>.
>>>>
>>>> I can fix this up, but I probably need to see Sasha's queue first for
>>>> the io_uring patches. I need to base it against that.
>>>
>>> Ok, wait for the next 5.3.y release in a few days and send stuff off of
>>> that if you can.
>>
>> Is there no "current" or similar tree to work of off? Would be a shame
>> to miss the next one, especially since the newer fixes are already in.
> 
> I'm about to push out the -rcs right now.  You can base off of that and
> send me the patch and I'll add it, or just wait a few days, either is
> fine.

Sounds good, thanks Greg.

-- 
Jens Axboe

Re: FAILED: patch "[PATCH] io_uring: fix up O_NONBLOCK handling for sockets" failed to apply to 5.3-stable tree

[Sasha Levin]

On Sun, Oct 27, 2019 at 02:39:06PM -0600, Jens Axboe wrote:
>On 10/27/19 2:26 PM, Greg KH wrote:
>> On Sun, Oct 27, 2019 at 02:22:06PM -0600, Jens Axboe wrote:
>>> On 10/27/19 2:00 PM, Greg KH wrote:
>>>> On Sun, Oct 27, 2019 at 12:58:14PM -0600, Jens Axboe wrote:
>>>>> On 10/27/19 9:53 AM, gregkh@linuxfoundation.org wrote:
>>>>>>
>>>>>> The patch below does not apply to the 5.3-stable tree.
>>>>>> If someone wants it applied there, or to any other stable or longterm
>>>>>> tree, then please email the backport, including the original git commit
>>>>>> id to <stable@vger.kernel.org>.
>>>>>
>>>>> I can fix this up, but I probably need to see Sasha's queue first for
>>>>> the io_uring patches. I need to base it against that.
>>>>
>>>> Ok, wait for the next 5.3.y release in a few days and send stuff off of
>>>> that if you can.
>>>
>>> Is there no "current" or similar tree to work of off? Would be a shame
>>> to miss the next one, especially since the newer fixes are already in.
>>
>> I'm about to push out the -rcs right now.  You can base off of that and
>> send me the patch and I'll add it, or just wait a few days, either is
>> fine.
>
>Sounds good, thanks Greg.

I'll queue up a backport for this. The conflict is due to not having the
io_queue_sqe()/__io_queue_sqe() split introduced by 4fe2c963154c3
("io_uring: add support for link with drain").

-- 
Thanks,
Sasha

Re: FAILED: patch "[PATCH] io_uring: fix up O_NONBLOCK handling for sockets" failed to apply to 5.3-stable tree

[Jens Axboe]

On 10/28/19 2:26 AM, Sasha Levin wrote:
> On Sun, Oct 27, 2019 at 02:39:06PM -0600, Jens Axboe wrote:
>> On 10/27/19 2:26 PM, Greg KH wrote:
>>> On Sun, Oct 27, 2019 at 02:22:06PM -0600, Jens Axboe wrote:
>>>> On 10/27/19 2:00 PM, Greg KH wrote:
>>>>> On Sun, Oct 27, 2019 at 12:58:14PM -0600, Jens Axboe wrote:
>>>>>> On 10/27/19 9:53 AM, gregkh@linuxfoundation.org wrote:
>>>>>>>
>>>>>>> The patch below does not apply to the 5.3-stable tree.
>>>>>>> If someone wants it applied there, or to any other stable or longterm
>>>>>>> tree, then please email the backport, including the original git commit
>>>>>>> id to <stable@vger.kernel.org>.
>>>>>>
>>>>>> I can fix this up, but I probably need to see Sasha's queue first for
>>>>>> the io_uring patches. I need to base it against that.
>>>>>
>>>>> Ok, wait for the next 5.3.y release in a few days and send stuff off of
>>>>> that if you can.
>>>>
>>>> Is there no "current" or similar tree to work of off? Would be a shame
>>>> to miss the next one, especially since the newer fixes are already in.
>>>
>>> I'm about to push out the -rcs right now.  You can base off of that and
>>> send me the patch and I'll add it, or just wait a few days, either is
>>> fine.
>>
>> Sounds good, thanks Greg.
> 
> I'll queue up a backport for this. The conflict is due to not having the
> io_queue_sqe()/__io_queue_sqe() split introduced by 4fe2c963154c3
> ("io_uring: add support for link with drain").

Thanks!

-- 
Jens Axboe