Some file systems, ocfs2 in this case, will return -EOPNOTSUPP for an IOCB_NOWAIT read/write attempt. While this can be argued to be correct, the usual return value for something that requires blocking issue is -EAGAIN. A refactoring io_uring commit dropped calling kiocb_done() for negative return values, which is otherwise where we already do that transformation. To ensure we catch it in both spots, check it in __io_read() itself as well. Reported-by: Robert Sander <r.sander@xxxxxxxxxxxxxxxxxxx> Link: https://fosstodon.org/@gurubert@xxxxxxxxxxxxxxxxxxxx/113112431889638440 Cc: stable@xxxxxxxxxxxxxxx Fixes: a08d195b586a ("io_uring/rw: split io_read() into a helper") Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> --- diff --git a/io_uring/rw.c b/io_uring/rw.c index c004d21e2f12..d85e2d41a992 100644 --- a/io_uring/rw.c +++ b/io_uring/rw.c @@ -855,6 +855,14 @@ static int __io_read(struct io_kiocb *req, unsigned int issue_flags) ret = io_iter_do_read(rw, &io->iter); + /* + * Some file systems like to return -EOPNOTSUPP for an IOCB_NOWAIT + * issue, even though they should be returning -EAGAIN. To be safe, + * retry from blocking context for either. + */ + if (ret == -EOPNOTSUPP && force_nonblock) + ret = -EAGAIN; + if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) { req->flags &= ~REQ_F_REISSUE; /* If we can poll, just do that. */ -- Jens Axboe
