From a38d1243704f501a4c42de1db1062ff6eba83453 Mon Sep 17 00:00:00 2001
From: Goldwyn Rodrigues <rgoldwyn@suse.com>
Date: Tue, 20 Jun 2017 07:05:45 -0500
Subject: fs: Introduce IOMAP_NOWAIT

IOCB_NOWAIT translates to IOMAP_NOWAIT for iomaps.
This is used by XFS in the XFS patch.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/iomap.c | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'fs/iomap.c')

diff --git a/fs/iomap.c b/fs/iomap.c
index 18f2f2b8ba2c..c71a64b97fba 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -881,6 +881,14 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 		flags |= IOMAP_WRITE;
 	}
 
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (filemap_range_has_page(mapping, start, end)) {
+			ret = -EAGAIN;
+			goto out_free_dio;
+		}
+		flags |= IOMAP_NOWAIT;
+	}
+
 	ret = filemap_write_and_wait_range(mapping, start, end);
 	if (ret)
 		goto out_free_dio;
-- 
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