Fixed the hash formula. Lite2 doesn't have phashinit(), so Lite2's hash

formula uses `& nchash'.  This is very broken when nchash is a prime
number instead of 1 less than a power of 2, but the Lite2 formula was
merged in.

Merged some cosmetic changes from Lite2, rev.1.21 and Lite1.  The merge
was difficult because the Lite2 code is essentially ours (phk's) except
where Lite2 improved or broke it.

Summary of the Lite2 changes:
- in the copyright, phk's rights have been transferred to the Regents.
  This change should be reviewed.
- nchENOENT went away; the "no" vnode is now simply 0.
- comments were improved.
- style was "improved".
- goto instead of Fanatism (sic) was considered bad :-).
- there are some small changes to support whiteouts.
- new cache entries are added in more cases.  More work is required
  near here to change the hash table size if kern.desiredvnodes is
  changed using sysctl.
- rescanning of the hash bucket in cache_purgevfs() was removed.  This
  change should be reviewed.

1 files changed, 14 insertions, 14 deletions

diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c
index 3c611a1..ef0f222 100644
--- a/sys/kern/vfs_cache.c
+++ b/sys/kern/vfs_cache.c
@@ -33,8 +33,8 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	@(#)vfs_cache.c	8.3 (Berkeley) 8/22/94
- * $Id$
+ *	@(#)vfs_cache.c	8.5 (Berkeley) 3/22/95
+ * $Id: vfs_cache.c,v 1.23 1997/02/22 09:39:31 peter Exp $
  */
 
 #include <sys/param.h>
@@ -75,15 +75,16 @@
  * Structures associated with name cacheing.
  */
 #define NCHHASH(dvp, cnp) \
-	(&nchashtbl[((dvp)->v_id + (cnp)->cn_hash) & nchash])
+	(&nchashtbl[((dvp)->v_id + (cnp)->cn_hash) % nchash])
 static LIST_HEAD(nchashhead, namecache) *nchashtbl;	/* Hash Table */
-static u_long nchash;			/* size of hash table - 1 */
-static int doingcache = 1;			/* 1 => enable the cache */
-SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0, "");
-static u_long numcache;			/* number of cache entries allocated */
+static u_long	nchash;			/* size of hash table */
+static u_long	numcache;		/* number of cache entries allocated */
 static TAILQ_HEAD(, namecache) nclruhead;	/* LRU chain */
 struct	nchstats nchstats;		/* cache effectiveness statistics */
 
+static int	doingcache = 1;		/* 1 => enable the cache */
+SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0, "");
+
 #ifdef NCH_STATISTICS
 u_long	nchnbr;
 #define NCHNBR(ncp) (ncp)->nc_nbr = ++nchnbr;
@@ -117,9 +118,9 @@ u_long	nchnbr;
 }
 
 /*
- * Lookup an entry in the cache 
+ * Lookup an entry in the cache
  *
- * We don't do this if the segment name is long, simply so the cache 
+ * We don't do this if the segment name is long, simply so the cache
  * can avoid holding long names (which would either waste space, or
  * add greatly to the complexity).
  *
@@ -144,7 +145,6 @@ cache_lookup(dvp, vpp, cnp)
 		cnp->cn_flags &= ~MAKEENTRY;
 		return (0);
 	}
-
 	if (cnp->cn_namelen > NCHNAMLEN) {
 		nchstats.ncs_long++;
 		cnp->cn_flags &= ~MAKEENTRY;
@@ -181,7 +181,7 @@ cache_lookup(dvp, vpp, cnp)
 		nchstats.ncs_badhits++;
 		PURGE(ncp);
 		return (0);
-	} 
+	}
 
 	/* We found a "positive" match, return the vnode */
         if (ncp->nc_vp) {
@@ -225,12 +225,10 @@ cache_enter(dvp, vp, cnp)
 	if (!doingcache)
 		return;
 
-#ifdef DIAGNOSTIC
 	if (cnp->cn_namelen > NCHNAMLEN) {
 		printf("cache_enter: name too long");
 		return;
 	}
-#endif
 
 	/*
 	 * We allocate a new entry if we are less than the maximum
@@ -256,6 +254,7 @@ cache_enter(dvp, vp, cnp)
 		/* give up */
 		return;
 	}
+
 	/*
 	 * Fill in cache info, if vp is NULL this is a "negative" cache entry.
 	 * For negative entries, we have to record whether it is a whiteout.
@@ -284,13 +283,14 @@ cache_enter(dvp, vp, cnp)
 void
 nchinit()
 {
+
 	TAILQ_INIT(&nclruhead);
 	nchashtbl = phashinit(desiredvnodes, M_CACHE, &nchash);
 }
 
 /*
  * Invalidate all entries to particular vnode.
- * 
+ *
  * We actually just increment the v_id, that will do it. The stale entries
  * will be purged by lookup as they get found. If the v_id wraps around, we
  * need to ditch the entire cache, to avoid confusion. No valid vnode will