NFSD: Update the NFSv2 WRITE argument decoder to use struct xdr_stream

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index 1eacaa2..11d27b2 100644 (file)
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -266,46 +266,36 @@ nfssvc_decode_readargs(struct svc_rqst *rqstp, __be32 *p)
 int
 nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
 {
+       struct xdr_stream *xdr = &rqstp->rq_arg_stream;
        struct nfsd_writeargs *args = rqstp->rq_argp;
-       unsigned int len, hdr, dlen;
        struct kvec *head = rqstp->rq_arg.head;
+       struct kvec *tail = rqstp->rq_arg.tail;
+       u32 beginoffset, totalcount;
+       size_t remaining;
 
-       p = decode_fh(p, &args->fh);
-       if (!p)
+       if (!svcxdr_decode_fhandle(xdr, &args->fh))
                return 0;
-
-       p++;                            /* beginoffset */
-       args->offset = ntohl(*p++);     /* offset */
-       p++;                            /* totalcount */
-       len = args->len = ntohl(*p++);
-       /*
-        * The protocol specifies a maximum of 8192 bytes.
-        */
-       if (len > NFSSVC_MAXBLKSIZE_V2)
+       /* beginoffset is ignored */
+       if (xdr_stream_decode_u32(xdr, &beginoffset) < 0)
                return 0;
-
-       /*
-        * Check to make sure that we got the right number of
-        * bytes.
-        */
-       hdr = (void*)p - head->iov_base;
-       if (hdr > head->iov_len)
+       if (xdr_stream_decode_u32(xdr, &args->offset) < 0)
+               return 0;
+       /* totalcount is ignored */
+       if (xdr_stream_decode_u32(xdr, &totalcount) < 0)
                return 0;
-       dlen = head->iov_len + rqstp->rq_arg.page_len - hdr;
 
-       /*
-        * Round the length of the data which was specified up to
-        * the next multiple of XDR units and then compare that
-        * against the length which was actually received.
-        * Note that when RPCSEC/GSS (for example) is used, the
-        * data buffer can be padded so dlen might be larger
-        * than required.  It must never be smaller.
-        */
-       if (dlen < XDR_QUADLEN(len)*4)
+       /* opaque data */
+       if (xdr_stream_decode_u32(xdr, &args->len) < 0)
+               return 0;
+       if (args->len > NFSSVC_MAXBLKSIZE_V2)
+               return 0;
+       remaining = head->iov_len + rqstp->rq_arg.page_len + tail->iov_len;
+       remaining -= xdr_stream_pos(xdr);
+       if (remaining < xdr_align_size(args->len))
                return 0;
+       args->first.iov_base = xdr->p;
+       args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
 
-       args->first.iov_base = (void *)p;
-       args->first.iov_len = head->iov_len - hdr;
        return 1;
 }