io_uring: no read/write-retry on -EAGAIN error and O_NONBLOCK marked file

Actually two things that need fixing up here:

- The io_rw_reissue() -EAGAIN retry is explicit to block devices and
  regular files, so don't ever attempt to do that on other types of
  files.

- If we hit -EAGAIN on a nonblock marked file, don't arm poll handler for
  it. It should just complete with -EAGAIN.

Cc: stable@vger.kernel.org
Reported-by: Norman Maurer <norman.maurer@googlemail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index b1ccd70..64c5a52 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2300,8 +2300,11 @@ end_req:
 static bool io_rw_reissue(struct io_kiocb *req, long res)
 {
 #ifdef CONFIG_BLOCK
+       umode_t mode = file_inode(req->file)->i_mode;
        int ret;
 
+       if (!S_ISBLK(mode) && !S_ISREG(mode))
+               return false;
        if ((res != -EAGAIN && res != -EOPNOTSUPP) || io_wq_current_is_worker())
                return false;
 
@@ -3146,6 +3149,9 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
                /* IOPOLL retry should happen for io-wq threads */
                if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
                        goto done;
+               /* no retry on NONBLOCK marked file */
+               if (req->file->f_flags & O_NONBLOCK)
+                       goto done;
                /* some cases will consume bytes even on error returns */
                iov_iter_revert(iter, iov_count - iov_iter_count(iter));
                ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false);
@@ -3287,10 +3293,14 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
         */
        if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
                ret2 = -EAGAIN;
+       /* no retry on NONBLOCK marked file */
+       if (ret2 == -EAGAIN && (req->file->f_flags & O_NONBLOCK))
+               goto done;
        if (!force_nonblock || ret2 != -EAGAIN) {
                /* IOPOLL retry should happen for io-wq threads */
                if ((req->ctx->flags & IORING_SETUP_IOPOLL) && ret2 == -EAGAIN)
                        goto copy_iov;
+done:
                kiocb_done(kiocb, ret2, cs);
        } else {
 copy_iov: