nfsd: clean up and clarify the cache expiration code

Add a preprocessor constant for the expiry time of cache entries, and
move the test for an expired entry into a function. Note that the current
code does not test for RC_INPROG. It just assumes that it won't take more
than 2 minutes to fill out an in-progress entry.

I'm not sure how valid that assumption is though, so let's just ensure
that we never consider an RC_INPROG entry to be expired.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/cache.h b/fs/nfsd/cache.h
index f8c6df8649dce05b7a9269e1968557e902a50046..9c7232b45103c6178a129a5e7c58fd22cc3fb964 100644 (file)
--- a/fs/nfsd/cache.h
+++ b/fs/nfsd/cache.h
@@ -70,6 +70,9 @@ enum {
  */
 #define RC_DELAY               (HZ/5)
 
+/* Cache entries expire after this time period */
+#define RC_EXPIRE              (120 * HZ)
+
 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 2cdc4be84553830df75b3216522a97bc1deb7ccb..634b8566aaef00dc5090d65b1cc233a8175afebb 100644 (file)
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -142,6 +142,13 @@ hash_refile(struct svc_cacherep *rp)
        hlist_add_head(&rp->c_hash, cache_hash + request_hash(rp->c_xid));
 }
 
+static inline bool
+nfsd_cache_entry_expired(struct svc_cacherep *rp)
+{
+       return rp->c_state != RC_INPROG &&
+              time_after(jiffies, rp->c_timestamp + RC_EXPIRE);
+}
+
 /*
  * Try to find an entry matching the current call in the cache. When none
  * is found, we grab the oldest unlocked entry off the LRU list.
@@ -175,7 +182,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
                if (rp->c_state != RC_UNUSED &&
                    xid == rp->c_xid && proc == rp->c_proc &&
                    proto == rp->c_prot && vers == rp->c_vers &&
-                   time_before(jiffies, rp->c_timestamp + 120*HZ) &&
+                   !nfsd_cache_entry_expired(rp) &&
                    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)) {
                        nfsdstats.rchits++;