[PATCH 1/2] aio: partial write return

[Rusty Russell <rusty@rustcorp.com.au>]

When an AIO write gets a non-retry error after writing some data
(eg. ENOSPC), it should return the amount written already, not the
error.  Just like write() is supposed to.

This was found by the libaio test suite.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-By: Zach Brown <zach.brown@oracle.com>
---
 fs/aio.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff -r 18802689361a fs/aio.c
--- a/fs/aio.c	Thu Jan 03 15:22:24 2008 +1100
+++ b/fs/aio.c	Thu Jan 03 18:05:25 2008 +1100
@@ -1346,6 +1350,13 @@ static ssize_t aio_rw_vect_retry(struct 
 	/* This means we must have transferred all that we could */
 	/* No need to retry anymore */
 	if ((ret == 0) || (iocb->ki_left == 0))
+		ret = iocb->ki_nbytes - iocb->ki_left;
+
+	/* If we managed to write some out we return that, rather than
+	 * the eventual error. */
+	if (opcode == IOCB_CMD_PWRITEV
+	    && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
+	    && iocb->ki_nbytes - iocb->ki_left)
 		ret = iocb->ki_nbytes - iocb->ki_left;
 
 	return ret;