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From: Max Kellermann <mk@cm4all.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Max Kellermann <mk@cm4all.com>,
	axboe@kernel.dk, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] fs/io_uring: fix O_PATH fds in openat, openat2, statx
Date: Thu, 7 May 2020 21:05:03 +0200	[thread overview]
Message-ID: <20200507190503.GA15998@rabbit.intern.cm-ag> (raw)
In-Reply-To: <20200507190131.GF23230@ZenIV.linux.org.uk>

On 2020/05/07 21:01, Al Viro <viro@zeniv.linux.org.uk> wrote:
> On Thu, May 07, 2020 at 08:57:25PM +0200, Max Kellermann wrote:
> > If an operation's flag `needs_file` is set, the function
> > io_req_set_file() calls io_file_get() to obtain a `struct file*`.
> > 
> > This fails for `O_PATH` file descriptors, because those have no
> > `struct file*`
> 
> O_PATH descriptors most certainly *do* have that.  What the hell
> are you talking about?

Oh, then my patch description (and my understanding of the root
problem) is wrong.  In my debugging session, io_file_get() on that fd
returned NULL, so I assumed O_PATH doesn't have that, but maybe there
are other reasons.

In any case, with a "real" fd, io_uring openat() succeeds, and my
patch makes the problem with O_PATH go away.

I guess I need to learn more about what happens inside io_file_get().

Max


  reply	other threads:[~2020-05-07 19:05 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-07 18:57 [PATCH] fs/io_uring: fix O_PATH fds in openat, openat2, statx Max Kellermann
2020-05-07 18:58 ` Jens Axboe
2020-05-07 19:01   ` Max Kellermann
2020-05-07 19:01 ` Al Viro
2020-05-07 19:05   ` Max Kellermann [this message]
2020-05-07 19:05   ` Jens Axboe
2020-05-07 19:12     ` Max Kellermann
2020-05-07 19:29     ` Al Viro
2020-05-07 19:37       ` Max Kellermann
2020-05-07 20:53       ` Jens Axboe
2020-05-07 22:06         ` Al Viro
2020-05-07 22:25           ` Jens Axboe
2020-05-07 22:44             ` Al Viro
2020-05-07 23:03               ` Jens Axboe
2020-05-07 23:31                 ` Al Viro
2020-05-08  2:28                   ` Jens Axboe
2020-05-08  2:53                     ` Jens Axboe
     [not found]                     ` <20200508152918.12340-1-hdanton@sina.com>
2020-05-08 15:33                       ` Jens Axboe

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