Re: [PATCH] fuse: Fix the return code of fuse_direct_IO() to deal with the error for aio

[Miklos Szeredi <miklos@szeredi.hu>]

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On Mon, Nov 18, 2019 at 3:24 AM Masayoshi Mizuma <msys.mizuma@gmail.com> wrote:
>
> From: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
>
> exit_aio() is sometimes stuck in wait_for_completion() after aio is issued
> with direct IO and the task receives a signal.
>
> That is because kioctx in mm->ioctx_table is in use by aio_kiocb.
> aio_kiocb->ki_refcnt is 1 at that time. That means iocb_put() isn't
> called correctly.
>
> fuse_get_req() returns as -EINTR when it's blocked and receives a signal.
> fuse_direct_IO() deals with the -EINTER as -EIOCBQUEUED and returns as
> -EIOCBQUEUED even though the aio isn't queued.
> As the result, aio_rw_done() doesn't handle the error, so iocb_put() isn't
> called via aio_complete_rw(), which is the callback.

Hi,

Thanks for the report.

Can you please test the attached patch (without your patch)?

Thanks,
Miklos

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---
 fs/fuse/file.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -713,8 +713,10 @@ static ssize_t fuse_async_req_send(struc
 
 	ia->ap.args.end = fuse_aio_complete_req;
 	err = fuse_simple_background(fc, &ia->ap.args, GFP_KERNEL);
+	if (err)
+		fuse_aio_complete_req(fc, &ia->ap.args, err);
 
-	return err ?: num_bytes;
+	return num_bytes;
 }
 
 static ssize_t fuse_send_read(struct fuse_io_args *ia, loff_t pos, size_t count,