[PATCH 06/10] fs: Introduce IOMAP_NOWAIT

[Goldwyn Rodrigues]

From: Goldwyn Rodrigues <rgold...@suse.com>

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

Reviewed-by: Christoph Hellwig <h...@lst.de>
Reviewed-by: Jan Kara <j...@suse.cz>
Signed-off-by: Goldwyn Rodrigues <rgold...@suse.com>
---
 fs/iomap.c            | 8 ++++++++
 include/linux/iomap.h | 1 +
 2 files changed, 9 insertions(+)

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;
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index f753e788da31..69f4e9470084 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -52,6 +52,7 @@ struct iomap {
 #define IOMAP_REPORT           (1 << 2) /* report extent status, e.g. FIEMAP */
 #define IOMAP_FAULT            (1 << 3) /* mapping for page fault */
 #define IOMAP_DIRECT           (1 << 4) /* direct I/O */
+#define IOMAP_NOWAIT           (1 << 5) /* Don't wait for writeback */
 
 struct iomap_ops {
        /*
-- 
2.12.0