iomap: Return -EAGAIN from iomap_write_iter()

If iomap_write_iter() encounters -EAGAIN, return -EAGAIN to the caller.

Signed-off-by: Stefan Roesch <shr@fb.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20220623175157.1715274-7-shr@fb.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
[axboe: make the suggested ternary edit]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/iomap/buffered-io.c

@@ -830,6 +830,10 @@ again:
 		length -= status;
 	} while (iov_iter_count(i) && length);
 
+	if (status == -EAGAIN) {
+		iov_iter_revert(i, written);
+		return -EAGAIN;
+	}
 	return written ? written : status;
 }