NFSD: Update nfsd_cache_append() to use xdr_stream

commit 49cecd8628a9855cd993792a0377559ea32d5e7c upstream.

When inserting a DRC-cached response into the reply buffer, ensure
that the reply buffer's xdr_stream is updated properly. Otherwise
the server will send a garbage response.

Cc: stable@vger.kernel.org # v6.3+
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index a8eda1c85829ecfeaed2b8ba170ab285f0f42b6f..1ad4f30d5f855e52c4c9edd29991a0996d427edb 100644 (file)
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -582,24 +582,17 @@ void nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp)
        return;
 }
 
-/*
- * Copy cached reply to current reply buffer. Should always fit.
- * FIXME as reply is in a page, we should just attach the page, and
- * keep a refcount....
- */
 static int
 nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *data)
 {
-       struct kvec     *vec = &rqstp->rq_res.head[0];
-
-       if (vec->iov_len + data->iov_len > PAGE_SIZE) {
-               printk(KERN_WARNING "nfsd: cached reply too large (%zd).\n",
-                               data->iov_len);
-               return 0;
-       }
-       memcpy((char*)vec->iov_base + vec->iov_len, data->iov_base, data->iov_len);
-       vec->iov_len += data->iov_len;
-       return 1;
+       __be32 *p;
+
+       p = xdr_reserve_space(&rqstp->rq_res_stream, data->iov_len);
+       if (unlikely(!p))
+               return false;
+       memcpy(p, data->iov_base, data->iov_len);
+       xdr_commit_encode(&rqstp->rq_res_stream);
+       return true;
 }
 
 /*