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: ba04291 ("io_uring: allow use of offset == -1 to mean file position") Link: axboe/liburing#501 Reported-by: Samuel Williams <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
dedewu6 · Dec 23, 2021 · 7b9762a · 7b9762a
1 parent d800c65
commit 7b9762a
Showing 1 changed file with 7 additions and 3 deletions.
diff --git 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));