NFS: Implement SEEK
The SEEK operation is used when an application makes an lseek call with
either the SEEK_HOLE or SEEK_DATA flags set. I fall back on
nfs_file_llseek() if the server does not have SEEK support.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c
new file mode 100644
index 0000000..c90469b
--- /dev/null
+++ b/fs/nfs/nfs42xdr.c
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2014 Anna Schumaker <Anna.Schumaker@Netapp.com>
+ */
+#ifndef __LINUX_FS_NFS_NFS4_2XDR_H
+#define __LINUX_FS_NFS_NFS4_2XDR_H
+
+#define encode_seek_maxsz (op_encode_hdr_maxsz + \
+ encode_stateid_maxsz + \
+ 2 /* offset */ + \
+ 1 /* whence */)
+#define decode_seek_maxsz (op_decode_hdr_maxsz + \
+ 1 /* eof */ + \
+ 1 /* whence */ + \
+ 2 /* offset */ + \
+ 2 /* length */)
+
+#define NFS4_enc_seek_sz (compound_encode_hdr_maxsz + \
+ encode_putfh_maxsz + \
+ encode_seek_maxsz)
+#define NFS4_dec_seek_sz (compound_decode_hdr_maxsz + \
+ decode_putfh_maxsz + \
+ decode_seek_maxsz)
+
+
+static void encode_seek(struct xdr_stream *xdr,
+ struct nfs42_seek_args *args,
+ struct compound_hdr *hdr)
+{
+ encode_op_hdr(xdr, OP_SEEK, decode_seek_maxsz, hdr);
+ encode_nfs4_stateid(xdr, &args->sa_stateid);
+ encode_uint64(xdr, args->sa_offset);
+ encode_uint32(xdr, args->sa_what);
+}
+
+/*
+ * Encode SEEK request
+ */
+static void nfs4_xdr_enc_seek(struct rpc_rqst *req,
+ struct xdr_stream *xdr,
+ struct nfs42_seek_args *args)
+{
+ struct compound_hdr hdr = {
+ .minorversion = nfs4_xdr_minorversion(&args->seq_args),
+ };
+
+ encode_compound_hdr(xdr, req, &hdr);
+ encode_sequence(xdr, &args->seq_args, &hdr);
+ encode_putfh(xdr, args->sa_fh, &hdr);
+ encode_seek(xdr, args, &hdr);
+ encode_nops(&hdr);
+}
+
+static int decode_seek(struct xdr_stream *xdr, struct nfs42_seek_res *res)
+{
+ int status;
+ __be32 *p;
+
+ status = decode_op_hdr(xdr, OP_SEEK);
+ if (status)
+ return status;
+
+ p = xdr_inline_decode(xdr, 4 + 8);
+ if (unlikely(!p))
+ goto out_overflow;
+
+ res->sr_eof = be32_to_cpup(p++);
+ p = xdr_decode_hyper(p, &res->sr_offset);
+ return 0;
+
+out_overflow:
+ print_overflow_msg(__func__, xdr);
+ return -EIO;
+}
+
+/*
+ * Decode SEEK request
+ */
+static int nfs4_xdr_dec_seek(struct rpc_rqst *rqstp,
+ struct xdr_stream *xdr,
+ struct nfs42_seek_res *res)
+{
+ struct compound_hdr hdr;
+ int status;
+
+ status = decode_compound_hdr(xdr, &hdr);
+ if (status)
+ goto out;
+ status = decode_sequence(xdr, &res->seq_res, rqstp);
+ if (status)
+ goto out;
+ status = decode_putfh(xdr);
+ if (status)
+ goto out;
+ status = decode_seek(xdr, res);
+out:
+ return status;
+}
+#endif /* __LINUX_FS_NFS_NFS4_2XDR_H */