Re: [LTP] [linus:master] [iomap] 219580eea1: ltp.writev07.fail

[Christoph Hellwig]

On Thu, Jul 13, 2023 at 05:34:55PM +0200, Cyril Hrubis wrote:
>                 iter.processed = iomap_write_iter(&iter, i);
> 
> +       iocb->ki_pos += iter.pos - iocb->ki_pos;
> +
>         if (unlikely(ret < 0))
>                 return ret;
> -       ret = iter.pos - iocb->ki_pos;
> -       iocb->ki_pos += ret;
> -       return ret;
> +
> +       return iter.pos - iocb->ki_pos;

I don't think this works, as iocb->ki_pos has been updated above.
What you want is probably the version below.  But so far I can't
reproduce anything yet..

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index adb92cdb24b009..02aea0174ddbcf 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -872,7 +872,7 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i,
 	while ((ret = iomap_iter(&iter, ops)) > 0)
 		iter.processed = iomap_write_iter(&iter, i);
 
-	if (unlikely(ret < 0))
+	if (iter.pos == iocb->ki_pos)
 		return ret;
 	ret = iter.pos - iocb->ki_pos;
 	iocb->ki_pos += ret;