diff options
| -rw-r--r-- | fs/nfsd/nfscache.c | 46 |
1 files changed, 35 insertions, 11 deletions
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c index c61391e8e09d..48f5ef944234 100644 --- a/fs/nfsd/nfscache.c +++ b/fs/nfsd/nfscache.c @@ -23,10 +23,22 @@ 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. */ static inline u32 request_hash(u32 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; |