[PATCH RFC 3/3] NFS41: send real read size in layoutget for DIO

[Peng Tao <bergwolf@gmail.com>]

From: Peng Tao <tao.peng@emc.com>

We don't have the real IO size information in buffer read, but for direct
read, we can get it from dreq->bytes_left. Let's make use of it.

Signed-off-by: Peng Tao <tao.peng@emc.com>
---
 fs/nfs/pnfs.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index e61a373..e4cfd1e 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1154,16 +1154,22 @@ out_forget_reply:
 void
 pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
 {
+	u64 rd_size = req->wb_bytes;
+
 	BUG_ON(pgio->pg_lseg != NULL);
 
 	if (req->wb_offset != req->wb_pgbase) {
 		nfs_pageio_reset_read_mds(pgio);
 		return;
 	}
+
+	if (pgio->pg_dreq != NULL)
+		rd_size = nfs_dreq_bytes_left(pgio->pg_dreq);
+
 	pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
 					   req->wb_context,
 					   req_offset(req),
-					   req->wb_bytes,
+					   rd_size,
 					   IOMODE_READ,
 					   GFP_KERNEL);
 	/* If no lseg, fall back to read through mds */
-- 
1.7.1.262.g5ef3d