linux-kernel - Re: [PATCH] fs/io_uring: fix O_PATH fds in openat, openat2, statx

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Message-ID: <a048108e-67e0-b261-ab56-312a98045255@kernel.dk>
Date:   Thu, 7 May 2020 12:58:50 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Max Kellermann <mk@...all.com>, linux-fsdevel@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] fs/io_uring: fix O_PATH fds in openat, openat2, statx

On 5/7/20 12:57 PM, 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*`, causing io_req_set_file() to throw `-EBADF`.  This
> breaks the operations `openat`, `openat2` and `statx`, where `O_PATH`
> file descriptors are commonly used.
> 
> The solution is to simply remove `needs_file` (and the accompanying
> flag `fd_non_reg`).  This flag was never needed because those
> operations use numeric file descriptor and don't use the `struct
> file*` obtained by io_req_set_file().

Do you happen to have a liburing test addition for this as well?

-- 
Jens Axboe