From 7b9762a5e8837b92a027d58d396a9d27f6440c36 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 22 Dec 2021 20:26:56 -0700 Subject: [PATCH] io_uring: zero iocb->ki_pos for stream file types io_uring supports using offset == -1 for using the current file position, and we read that in as part of read/write command setup. For the non-iter read/write types we pass in NULL for the position pointer, but for the iter types we should not be passing any anything but 0 for the position for a stream. Clear kiocb->ki_pos if the file is a stream, don't leave it as -1. If we do, then the request will error with -ESPIPE. Fixes: ba04291eb66e ("io_uring: allow use of offset == -1 to mean file position") Link: https://github.com/axboe/liburing/discussions/501 Reported-by: Samuel Williams Signed-off-by: Jens Axboe --- fs/io_uring.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index d5ab0e9..fb2a0cb 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2891,9 +2891,13 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) req->flags |= io_file_get_flags(file) << REQ_F_SUPPORT_NOWAIT_BIT; kiocb->ki_pos = READ_ONCE(sqe->off); - if (kiocb->ki_pos == -1 && !(file->f_mode & FMODE_STREAM)) { - req->flags |= REQ_F_CUR_POS; - kiocb->ki_pos = file->f_pos; + if (kiocb->ki_pos == -1) { + if (!(file->f_mode & FMODE_STREAM)) { + req->flags |= REQ_F_CUR_POS; + kiocb->ki_pos = file->f_pos; + } else { + kiocb->ki_pos = 0; + } } kiocb->ki_flags = iocb_flags(file); ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags)); -- 2.7.4