From e2c2b4482bcb6913f5574efbce1e7e7f6469745d Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@redhat.com>
Date: Wed, 27 Mar 2013 10:15:37 -0400
Subject: [PATCH] --- yaml --- r: 372159 b: refs/heads/master c:
 9dc56143c298692276231735ec6546c1fac596e0 h: refs/heads/master i:   372157:
 dc2bc53032dd69c2ddd67361027c0b4404838f72   372155:
 4530bb8889ec99ecb88dbbc2b2e737cc8b578a3c   372151:
 62706790b88b9ab2e27067ba3fb922da9db73dbc   372143:
 99b6ba1f0732c544bc4e20b861c33305c7b312bb   372127:
 4bfaccde0a0b7c785af10ab57a584b150a264a19   372095:
 add6ba461db02f8d1c0cfa588aeefcded37d7e8a v: v3

---
 [refs]                   |  2 +-
 trunk/fs/nfsd/nfscache.c | 46 ++++++++++++++++++++++++++++++----------
 2 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/[refs] b/[refs]
index 417994a55d48..77b6eac11a48 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0b9ea37f24e247ed69baabf27fb211aa6a3e7622
+refs/heads/master: 9dc56143c298692276231735ec6546c1fac596e0
diff --git a/trunk/fs/nfsd/nfscache.c b/trunk/fs/nfsd/nfscache.c
index c61391e8e09d..48f5ef944234 100644
--- a/trunk/fs/nfsd/nfscache.c
+++ b/trunk/fs/nfsd/nfscache.c
@@ -23,9 +23,21 @@
 static struct hlist_head *	cache_hash;
 static struct list_head 	lru_head;
 static struct kmem_cache	*drc_slab;
-static unsigned int		num_drc_entries;
+
+/* max number of entries allowed in the cache */
 static unsigned int		max_drc_entries;
 
+/*
+ * Stats and other tracking of on the duplicate reply cache. All of these and
+ * the "rc" fields in nfsdstats are protected by the cache_lock
+ */
+
+/* total number of entries */
+static unsigned int		num_drc_entries;
+
+/* cache misses due only to checksum comparison failures */
+static unsigned int		payload_misses;
+
 /*
  * Calculate the hash index from an XID.
  */
@@ -273,6 +285,26 @@ nfsd_cache_csum(struct svc_rqst *rqstp)
 	return csum;
 }
 
+static bool
+nfsd_cache_match(struct svc_rqst *rqstp, __wsum csum, struct svc_cacherep *rp)
+{
+	/* Check RPC header info first */
+	if (rqstp->rq_xid != rp->c_xid || rqstp->rq_proc != rp->c_proc ||
+	    rqstp->rq_prot != rp->c_prot || rqstp->rq_vers != rp->c_vers ||
+	    rqstp->rq_arg.len != rp->c_len ||
+	    !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 false;
+
+	/* compare checksum of NFS data */
+	if (csum != rp->c_csum) {
+		++payload_misses;
+		return false;
+	}
+
+	return true;
+}
+
 /*
  * Search the request hash for an entry that matches the given rqstp.
  * Must be called with cache_lock held. Returns the found entry or
@@ -283,18 +315,10 @@ nfsd_cache_search(struct svc_rqst *rqstp, __wsum csum)
 {
 	struct svc_cacherep	*rp;
 	struct hlist_head 	*rh;
-	__be32			xid = rqstp->rq_xid;
-	u32			proto =  rqstp->rq_prot,
-				vers = rqstp->rq_vers,
-				proc = rqstp->rq_proc;
 
-	rh = &cache_hash[request_hash(xid)];
+	rh = &cache_hash[request_hash(rqstp->rq_xid)];
 	hlist_for_each_entry(rp, 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 && csum == rp->c_csum &&
-		    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))
+		if (nfsd_cache_match(rqstp, csum, rp))
 			return rp;
 	}
 	return NULL;