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From: Hao Xu <[email protected]>
To: [email protected], Jens Axboe <[email protected]>
Cc: Dominique Martinet <[email protected]>,
	Pavel Begunkov <[email protected]>,
	Christian Brauner <[email protected]>,
	Alexander Viro <[email protected]>,
	Stefan Roesch <[email protected]>, Clay Harris <[email protected]>,
	Dave Chinner <[email protected]>,
	[email protected], Wanpeng Li <[email protected]>
Subject: [PATCH RFC 5/5] disable fixed file for io_uring getdents for now
Date: Tue, 18 Jul 2023 21:21:12 +0800	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

From: Hao Xu <[email protected]>

Fixed file for io_uring getdents can trigger race problem. Users can
register a file to be fixed file in io_uring and then remove other
reference so that there are only fixed file reference of that file.
And then they can issue concurrent async getdents requests or both
async and sync getdents requests without holding the f_pos_lock
since there is a f_count == 1 optimization.

Signed-off-by: Hao Xu <[email protected]>
---
 io_uring/fs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/io_uring/fs.c b/io_uring/fs.c
index 480f25677fed..dc74676b1499 100644
--- a/io_uring/fs.c
+++ b/io_uring/fs.c
@@ -303,6 +303,8 @@ int io_getdents_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	struct io_getdents *gd = io_kiocb_to_cmd(req, struct io_getdents);
 
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
 	if (READ_ONCE(sqe->off) != 0)
 		return -EINVAL;
 
-- 
2.25.1


  parent reply	other threads:[~2023-07-18 13:22 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-18 13:21 [PATCH v4 0/5] io_uring getdents Hao Xu
2023-07-18 13:21 ` [PATCH 1/5] fs: split off vfs_getdents function of getdents64 syscall Hao Xu
2023-07-18 13:21 ` [PATCH 2/5] vfs_getdents/struct dir_context: add flags field Hao Xu
2023-07-18 13:21 ` [PATCH 3/5] io_uring: add support for getdents Hao Xu
2023-07-19  8:56   ` Hao Xu
2023-07-26 15:00   ` Christian Brauner
2023-07-27 11:51     ` Hao Xu
2023-07-27 14:27       ` Christian Brauner
2023-07-27 15:12         ` Pavel Begunkov
2023-07-27 15:52           ` Christian Brauner
2023-07-27 16:17             ` Pavel Begunkov
2023-07-27 16:28               ` Christian Brauner
2023-07-31  1:58                 ` Dave Chinner
2023-07-31  7:34                   ` Hao Xu
2023-07-31  7:50                     ` Christian Brauner
2023-07-31  7:40                   ` Christian Brauner
2023-07-30 18:02         ` Hao Xu
2023-07-31  8:18           ` Christian Brauner
2023-07-31  9:31             ` Hao Xu
2023-07-31  1:33         ` Dave Chinner
2023-07-31  8:13           ` Christian Brauner
2023-07-31 15:26             ` Darrick J. Wong
2023-07-31 22:18               ` Dave Chinner
2023-08-01  0:28               ` Jens Axboe
2023-08-01  0:47                 ` Matthew Wilcox
2023-08-01  0:49                   ` Jens Axboe
2023-08-01  1:01                     ` Matthew Wilcox
2023-08-01  7:00                       ` Christian Brauner
2023-08-01  6:59                     ` Christian Brauner
2023-08-01  7:17                 ` Christian Brauner
2023-08-08  4:34                 ` Hao Xu
2023-08-08  5:18                   ` Hao Xu
2023-08-08  9:33                 ` Hao Xu
2023-08-08 22:55                   ` Jens Axboe
2023-08-01 18:39             ` Hao Xu
2023-07-18 13:21 ` [PATCH 4/5] xfs: add NOWAIT semantics for readdir Hao Xu
2023-07-19  2:35   ` kernel test robot
2023-07-18 13:21 ` Hao Xu [this message]
2023-07-26 14:23   ` [PATCH RFC 5/5] disable fixed file for io_uring getdents for now Christian Brauner
2023-07-27 12:09     ` Hao Xu
2023-07-19  6:04 ` [PATCH v4 0/5] io_uring getdents Christian Brauner

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