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From:   schumaker.anna@gmail.com
To:     linux-nfs@vger.kernel.org
Cc:     Anna.Schumaker@Netapp.com
Subject: [PATCH v3 08/10] NFS: Add READ_PLUS hole segment decoding
Date:   Mon,  3 Aug 2020 13:00:11 -0400
Message-Id: <20200803170013.1348350-9-Anna.Schumaker@Netapp.com>
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From: Anna Schumaker <Anna.Schumaker@Netapp.com>

We keep things simple for now by only decoding a single hole or data
segment returned by the server, even if they returned more to us.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 fs/nfs/nfs42xdr.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c
index 9a1e18295e55..791e90353bc2 100644
--- a/fs/nfs/nfs42xdr.c
+++ b/fs/nfs/nfs42xdr.c
@@ -53,7 +53,7 @@
 #define decode_read_plus_maxsz		(op_decode_hdr_maxsz + \
 					 1 /* rpr_eof */ + \
 					 1 /* rpr_contents count */ + \
-					 NFS42_READ_PLUS_SEGMENT_SIZE)
+					 2 * NFS42_READ_PLUS_SEGMENT_SIZE)
 #define encode_seek_maxsz		(op_encode_hdr_maxsz + \
 					 encode_stateid_maxsz + \
 					 2 /* offset */ + \
@@ -768,6 +768,29 @@ static int decode_read_plus_data(struct xdr_stream *xdr, struct nfs_pgio_res *re
 	return 0;
 }
 
+static int decode_read_plus_hole(struct xdr_stream *xdr, struct nfs_pgio_res *res,
+				 uint32_t *eof)
+{
+	uint64_t offset, length, recvd;
+	__be32 *p;
+
+	p = xdr_inline_decode(xdr, 8 + 8);
+	if (unlikely(!p))
+		return -EIO;
+
+	p = xdr_decode_hyper(p, &offset);
+	p = xdr_decode_hyper(p, &length);
+
+	recvd = xdr_expand_hole(xdr, 0, length);
+	if (recvd < length) {
+		*eof = 0;
+		length = recvd;
+	}
+
+	res->count += length;
+	return 0;
+}
+
 static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res)
 {
 	uint32_t eof, segments, type;
@@ -794,6 +817,8 @@ static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res)
 	type = be32_to_cpup(p++);
 	if (type == NFS4_CONTENT_DATA)
 		status = decode_read_plus_data(xdr, res, &eof);
+	else if (type == NFS4_CONTENT_HOLE)
+		status = decode_read_plus_hole(xdr, res, &eof);
 	else
 		return -EINVAL;
 
-- 
2.27.0