[PATCH v2 4/6] NFS: Add READ_PLUS support for hole segments

[Anna Schumaker <Anna.Schumaker@netapp.com>]

This patch adds support for decoding a single hole segment returned by
the server.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 fs/nfs/nfs42xdr.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c
index 3d7c01b..17126e8 100644
--- a/fs/nfs/nfs42xdr.c
+++ b/fs/nfs/nfs42xdr.c
@@ -212,6 +212,30 @@ out_overflow:
 	return -EIO;
 }
 
+static int decode_read_plus_hole(struct xdr_stream *xdr, struct nfs_pgio_res *res)
+{
+	__be32 *p;
+	uint64_t offset, length;
+	size_t recvd;
+
+	p = xdr_inline_decode(xdr, 8 + 8);
+	if (unlikely(!p))
+		goto out_overflow;
+
+	p = xdr_decode_hyper(p, &offset);
+	p = xdr_decode_hyper(p, &length);
+
+	recvd = xdr_expand_hole(xdr, 0, length);
+	if (recvd < length)
+		res->eof = 0;
+
+	res->count = recvd;
+	return 0;
+out_overflow:
+	print_overflow_msg(__func__, xdr);
+	return -EIO;
+}
+
 static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res)
 {
 	__be32 *p;
@@ -240,7 +264,7 @@ static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res)
 	if (type == NFS4_CONTENT_DATA)
 		status = decode_read_plus_data(xdr, res);
 	else
-		status = -ENOTSUPP;
+		status = decode_read_plus_hole(xdr, res);
 
 	if (segments > 1)
 		res->eof = 0;
-- 
2.2.2