diff --git a/fs/nfsd/cache.h b/fs/nfsd/cache.h
index 9c7232b..4822db3 100644
--- a/fs/nfsd/cache.h
+++ b/fs/nfsd/cache.h
@@ -29,6 +29,8 @@ struct svc_cacherep {
 	u32			c_prot;
 	u32			c_proc;
 	u32			c_vers;
+	unsigned int		c_len;
+	u32			c_crc;
 	unsigned long		c_timestamp;
 	union {
 		struct kvec	u_vec;
@@ -73,6 +75,9 @@ enum {
 /* Cache entries expire after this time period */
 #define RC_EXPIRE		(120 * HZ)
 
+/* Checksum this amount of the request */
+#define RC_CSUMLEN		(256U)
+
 int	nfsd_reply_cache_init(void);
 void	nfsd_reply_cache_shutdown(void);
 int	nfsd_cache_lookup(struct svc_rqst *);
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index d16a5d6..cb655f3 100644
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -11,6 +11,7 @@
 #include <linux/slab.h>
 #include <linux/sunrpc/clnt.h>
 #include <linux/highmem.h>
+#include <linux/crc32.h>
 
 #include "nfsd.h"
 #include "cache.h"
@@ -24,6 +25,7 @@ static struct list_head 	lru_head;
 static struct kmem_cache	*drc_slab;
 static unsigned int		num_drc_entries;
 static unsigned int		max_drc_entries;
+static u32			crc_seed;
 
 /*
  * Calculate the hash index from an XID.
@@ -130,6 +132,9 @@ int nfsd_reply_cache_init(void)
 	INIT_LIST_HEAD(&lru_head);
 	max_drc_entries = nfsd_cache_size_limit();
 	num_drc_entries = 0;
+
+	/* Is a random seed any better than some well-defined constant? */
+	get_random_bytes(&crc_seed, sizeof(crc_seed));
 	return 0;
 out_nomem:
 	printk(KERN_ERR "nfsd: failed to allocate reply cache\n");
@@ -238,12 +243,37 @@ nfsd_reply_cache_shrink(struct shrinker *shrink, struct shrink_control *sc)
 }
 
 /*
+ * Walk an xdr_buf and get a CRC for at most the first RC_CSUMLEN bytes
+ */
+static u32
+nfsd_cache_crc(struct xdr_buf *buf)
+{
+	u32 crc;
+	const unsigned char *p = buf->head[0].iov_base;
+	size_t csum_len = min_t(size_t, buf->head[0].iov_len + buf->page_len,
+					RC_CSUMLEN);
+	size_t len = min(buf->head[0].iov_len, csum_len);
+
+	/* rq_arg.head first */
+	crc = crc32(crc_seed, p, len);
+	csum_len -= len;
+
+	/* Nothing left */
+	if (!csum_len)
+		return crc;
+
+	/* checksum the rest from the page_array */
+	p = page_address(buf->pages[0]) + buf->page_base;
+	return crc32(crc, p, csum_len);
+}
+
+/*
  * Search the request hash for an entry that matches the given rqstp.
  * Must be called with cache_lock held. Returns the found entry or
  * NULL on failure.
  */
 static struct svc_cacherep *
-nfsd_cache_search(struct svc_rqst *rqstp)
+nfsd_cache_search(struct svc_rqst *rqstp, u32 crc)
 {
 	struct svc_cacherep	*rp;
 	struct hlist_node	*hn;
@@ -257,6 +287,7 @@ nfsd_cache_search(struct svc_rqst *rqstp)
 	hlist_for_each_entry(rp, hn, rh, c_hash) {
 		if (xid == rp->c_xid && proc == rp->c_proc &&
 		    proto == rp->c_prot && vers == rp->c_vers &&
+		    rqstp->rq_arg.len == rp->c_len && crc == rp->c_crc &&
 		    rpc_cmp_addr(svc_addr(rqstp), (struct sockaddr *)&rp->c_addr) &&
 		    rpc_get_port(svc_addr(rqstp)) == rpc_get_port((struct sockaddr *)&rp->c_addr))
 			return rp;
@@ -276,7 +307,8 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
 	__be32			xid = rqstp->rq_xid;
 	u32			proto =  rqstp->rq_prot,
 				vers = rqstp->rq_vers,
-				proc = rqstp->rq_proc;
+				proc = rqstp->rq_proc,
+				crc;
 	unsigned long		age;
 	int type = rqstp->rq_cachetype;
 	int rtn;
@@ -287,10 +319,12 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
 		return RC_DOIT;
 	}
 
+	crc = nfsd_cache_crc(&rqstp->rq_arg);
+
 	spin_lock(&cache_lock);
 	rtn = RC_DOIT;
 
-	rp = nfsd_cache_search(rqstp);
+	rp = nfsd_cache_search(rqstp, crc);
 	if (rp)
 		goto found_entry;
 
@@ -318,7 +352,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
 	 * Must search again just in case someone inserted one
 	 * after we dropped the lock above.
 	 */
-	found = nfsd_cache_search(rqstp);
+	found = nfsd_cache_search(rqstp, crc);
 	if (found) {
 		nfsd_reply_cache_free_locked(rp);
 		rp = found;
@@ -344,6 +378,8 @@ setup_entry:
 	rpc_set_port((struct sockaddr *)&rp->c_addr, rpc_get_port(svc_addr(rqstp)));
 	rp->c_prot = proto;
 	rp->c_vers = vers;
+	rp->c_len = rqstp->rq_arg.len;
+	rp->c_crc = crc;
 
 	hash_refile(rp);
 	lru_put_end(rp);
