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-rw-r--r--sys/fs/coda/coda_namecache.c765
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diff --git a/sys/fs/coda/coda_namecache.c b/sys/fs/coda/coda_namecache.c
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+++ b/sys/fs/coda/coda_namecache.c
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+/*
+ *
+ * Coda: an Experimental Distributed File System
+ * Release 3.1
+ *
+ * Copyright (c) 1987-1998 Carnegie Mellon University
+ * All Rights Reserved
+ *
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation, and
+ * that credit is given to Carnegie Mellon University in all documents
+ * and publicity pertaining to direct or indirect use of this code or its
+ * derivatives.
+ *
+ * CODA IS AN EXPERIMENTAL SOFTWARE SYSTEM AND IS KNOWN TO HAVE BUGS,
+ * SOME OF WHICH MAY HAVE SERIOUS CONSEQUENCES. CARNEGIE MELLON ALLOWS
+ * FREE USE OF THIS SOFTWARE IN ITS "AS IS" CONDITION. CARNEGIE MELLON
+ * DISCLAIMS ANY LIABILITY OF ANY KIND FOR ANY DAMAGES WHATSOEVER
+ * RESULTING DIRECTLY OR INDIRECTLY FROM THE USE OF THIS SOFTWARE OR OF
+ * ANY DERIVATIVE WORK.
+ *
+ * Carnegie Mellon encourages users of this software to return any
+ * improvements or extensions that they make, and to grant Carnegie
+ * Mellon the rights to redistribute these changes without encumbrance.
+ *
+ * @(#) src/sys/coda/coda_namecache.c,v 1.1.1.1 1998/08/29 21:14:52 rvb Exp $
+ * $FreeBSD$
+ *
+ */
+
+/*
+ * Mach Operating System
+ * Copyright (c) 1990 Carnegie-Mellon University
+ * Copyright (c) 1989 Carnegie-Mellon University
+ * All rights reserved. The CMU software License Agreement specifies
+ * the terms and conditions for use and redistribution.
+ */
+
+/*
+ * This code was written for the Coda file system at Carnegie Mellon University.
+ * Contributers include David Steere, James Kistler, and M. Satyanarayanan.
+ */
+
+/*
+ * This module contains the routines to implement the CODA name cache. The
+ * purpose of this cache is to reduce the cost of translating pathnames
+ * into Vice FIDs. Each entry in the cache contains the name of the file,
+ * the vnode (FID) of the parent directory, and the cred structure of the
+ * user accessing the file.
+ *
+ * The first time a file is accessed, it is looked up by the local Venus
+ * which first insures that the user has access to the file. In addition
+ * we are guaranteed that Venus will invalidate any name cache entries in
+ * case the user no longer should be able to access the file. For these
+ * reasons we do not need to keep access list information as well as a
+ * cred structure for each entry.
+ *
+ * The table can be accessed through the routines cnc_init(), cnc_enter(),
+ * cnc_lookup(), cnc_rmfidcred(), cnc_rmfid(), cnc_rmcred(), and cnc_purge().
+ * There are several other routines which aid in the implementation of the
+ * hash table.
+ */
+
+/*
+ * NOTES: rvb@cs
+ * 1. The name cache holds a reference to every vnode in it. Hence files can not be
+ * closed or made inactive until they are released.
+ * 2. coda_nc_name(cp) was added to get a name for a cnode pointer for debugging.
+ * 3. coda_nc_find() has debug code to detect when entries are stored with different
+ * credentials. We don't understand yet, if/how entries are NOT EQ but still
+ * EQUAL
+ * 4. I wonder if this name cache could be replace by the vnode name cache.
+ * The latter has no zapping functions, so probably not.
+ */
+
+#include <sys/param.h>
+#include <sys/errno.h>
+#include <sys/malloc.h>
+#include <sys/ucred.h>
+#include <sys/select.h>
+
+#ifndef insque
+#include <sys/systm.h>
+#endif /* insque */
+
+#include <vm/vm.h>
+#include <vm/vm_object.h>
+
+#include <coda/coda.h>
+#include <coda/cnode.h>
+#include <coda/coda_namecache.h>
+
+#ifdef DEBUG
+#include <coda/coda_vnops.h>
+#endif
+
+/*
+ * Declaration of the name cache data structure.
+ */
+
+int coda_nc_use = 1; /* Indicate use of CODA Name Cache */
+int coda_nc_size = CODA_NC_CACHESIZE; /* size of the cache */
+int coda_nc_hashsize = CODA_NC_HASHSIZE; /* size of the primary hash */
+
+struct coda_cache *coda_nc_heap; /* pointer to the cache entries */
+struct coda_hash *coda_nc_hash; /* hash table of coda_cache pointers */
+struct coda_lru coda_nc_lru; /* head of lru chain */
+
+struct coda_nc_statistics coda_nc_stat; /* Keep various stats */
+
+/*
+ * for testing purposes
+ */
+int coda_nc_debug = 0;
+
+/*
+ * Entry points for the CODA Name Cache
+ */
+static struct coda_cache *coda_nc_find(struct cnode *dcp, const char *name, int namelen,
+ struct ucred *cred, int hash);
+static void coda_nc_remove(struct coda_cache *cncp, enum dc_status dcstat);
+
+/*
+ * Initialize the cache, the LRU structure and the Hash structure(s)
+ */
+
+#define TOTAL_CACHE_SIZE (sizeof(struct coda_cache) * coda_nc_size)
+#define TOTAL_HASH_SIZE (sizeof(struct coda_hash) * coda_nc_hashsize)
+
+int coda_nc_initialized = 0; /* Initially the cache has not been initialized */
+
+void
+coda_nc_init(void)
+{
+ int i;
+
+ /* zero the statistics structure */
+
+ bzero(&coda_nc_stat, (sizeof(struct coda_nc_statistics)));
+
+#ifdef CODA_VERBOSE
+ printf("CODA NAME CACHE: CACHE %d, HASH TBL %d\n", CODA_NC_CACHESIZE, CODA_NC_HASHSIZE);
+#endif
+ CODA_ALLOC(coda_nc_heap, struct coda_cache *, TOTAL_CACHE_SIZE);
+ CODA_ALLOC(coda_nc_hash, struct coda_hash *, TOTAL_HASH_SIZE);
+
+ coda_nc_lru.lru_next =
+ coda_nc_lru.lru_prev = (struct coda_cache *)LRU_PART(&coda_nc_lru);
+
+
+ for (i=0; i < coda_nc_size; i++) { /* initialize the heap */
+ CODA_NC_LRUINS(&coda_nc_heap[i], &coda_nc_lru);
+ CODA_NC_HSHNUL(&coda_nc_heap[i]);
+ coda_nc_heap[i].cp = coda_nc_heap[i].dcp = (struct cnode *)0;
+ }
+
+ for (i=0; i < coda_nc_hashsize; i++) { /* initialize the hashtable */
+ CODA_NC_HSHNUL((struct coda_cache *)&coda_nc_hash[i]);
+ }
+
+ coda_nc_initialized++;
+}
+
+/*
+ * Auxillary routines -- shouldn't be entry points
+ */
+
+static struct coda_cache *
+coda_nc_find(dcp, name, namelen, cred, hash)
+ struct cnode *dcp;
+ const char *name;
+ int namelen;
+ struct ucred *cred;
+ int hash;
+{
+ /*
+ * hash to find the appropriate bucket, look through the chain
+ * for the right entry (especially right cred, unless cred == 0)
+ */
+ struct coda_cache *cncp;
+ int count = 1;
+
+ CODA_NC_DEBUG(CODA_NC_FIND,
+ myprintf(("coda_nc_find(dcp %p, name %s, len %d, cred %p, hash %d\n",
+ dcp, name, namelen, cred, hash));)
+
+ for (cncp = coda_nc_hash[hash].hash_next;
+ cncp != (struct coda_cache *)&coda_nc_hash[hash];
+ cncp = cncp->hash_next, count++)
+ {
+
+ if ((CODA_NAMEMATCH(cncp, name, namelen, dcp)) &&
+ ((cred == 0) || (cncp->cred == cred)))
+ {
+ /* compare cr_uid instead */
+ coda_nc_stat.Search_len += count;
+ return(cncp);
+ }
+#ifdef DEBUG
+ else if (CODA_NAMEMATCH(cncp, name, namelen, dcp)) {
+ printf("coda_nc_find: name %s, new cred = %p, cred = %p\n",
+ name, cred, cncp->cred);
+ printf("nref %d, nuid %d, ngid %d // oref %d, ocred %d, ogid %d\n",
+ cred->cr_ref, cred->cr_uid, cred->cr_gid,
+ cncp->cred->cr_ref, cncp->cred->cr_uid, cncp->cred->cr_gid);
+ print_cred(cred);
+ print_cred(cncp->cred);
+ }
+#endif
+ }
+
+ return((struct coda_cache *)0);
+}
+
+/*
+ * Enter a new (dir cnode, name) pair into the cache, updating the
+ * LRU and Hash as needed.
+ */
+void
+coda_nc_enter(dcp, name, namelen, cred, cp)
+ struct cnode *dcp;
+ const char *name;
+ int namelen;
+ struct ucred *cred;
+ struct cnode *cp;
+{
+ struct coda_cache *cncp;
+ int hash;
+
+ if (coda_nc_use == 0) /* Cache is off */
+ return;
+
+ CODA_NC_DEBUG(CODA_NC_ENTER,
+ myprintf(("Enter: dcp %p cp %p name %s cred %p \n",
+ dcp, cp, name, cred)); )
+
+ if (namelen > CODA_NC_NAMELEN) {
+ CODA_NC_DEBUG(CODA_NC_ENTER,
+ myprintf(("long name enter %s\n",name));)
+ coda_nc_stat.long_name_enters++; /* record stats */
+ return;
+ }
+
+ hash = CODA_NC_HASH(name, namelen, dcp);
+ cncp = coda_nc_find(dcp, name, namelen, cred, hash);
+ if (cncp != (struct coda_cache *) 0) {
+ coda_nc_stat.dbl_enters++; /* duplicate entry */
+ return;
+ }
+
+ coda_nc_stat.enters++; /* record the enters statistic */
+
+ /* Grab the next element in the lru chain */
+ cncp = CODA_NC_LRUGET(coda_nc_lru);
+
+ CODA_NC_LRUREM(cncp); /* remove it from the lists */
+
+ if (CODA_NC_VALID(cncp)) {
+ /* Seems really ugly, but we have to decrement the appropriate
+ hash bucket length here, so we have to find the hash bucket
+ */
+ coda_nc_hash[CODA_NC_HASH(cncp->name, cncp->namelen, cncp->dcp)].length--;
+
+ coda_nc_stat.lru_rm++; /* zapped a valid entry */
+ CODA_NC_HSHREM(cncp);
+ vrele(CTOV(cncp->dcp));
+ vrele(CTOV(cncp->cp));
+ crfree(cncp->cred);
+ }
+
+ /*
+ * Put a hold on the current vnodes and fill in the cache entry.
+ */
+ vref(CTOV(cp));
+ vref(CTOV(dcp));
+ crhold(cred);
+ cncp->dcp = dcp;
+ cncp->cp = cp;
+ cncp->namelen = namelen;
+ cncp->cred = cred;
+
+ bcopy(name, cncp->name, (unsigned)namelen);
+
+ /* Insert into the lru and hash chains. */
+
+ CODA_NC_LRUINS(cncp, &coda_nc_lru);
+ CODA_NC_HSHINS(cncp, &coda_nc_hash[hash]);
+ coda_nc_hash[hash].length++; /* Used for tuning */
+
+ CODA_NC_DEBUG(CODA_NC_PRINTCODA_NC, print_coda_nc(); )
+}
+
+/*
+ * Find the (dir cnode, name) pair in the cache, if it's cred
+ * matches the input, return it, otherwise return 0
+ */
+struct cnode *
+coda_nc_lookup(dcp, name, namelen, cred)
+ struct cnode *dcp;
+ const char *name;
+ int namelen;
+ struct ucred *cred;
+{
+ int hash;
+ struct coda_cache *cncp;
+
+ if (coda_nc_use == 0) /* Cache is off */
+ return((struct cnode *) 0);
+
+ if (namelen > CODA_NC_NAMELEN) {
+ CODA_NC_DEBUG(CODA_NC_LOOKUP,
+ myprintf(("long name lookup %s\n",name));)
+ coda_nc_stat.long_name_lookups++; /* record stats */
+ return((struct cnode *) 0);
+ }
+
+ /* Use the hash function to locate the starting point,
+ then the search routine to go down the list looking for
+ the correct cred.
+ */
+
+ hash = CODA_NC_HASH(name, namelen, dcp);
+ cncp = coda_nc_find(dcp, name, namelen, cred, hash);
+ if (cncp == (struct coda_cache *) 0) {
+ coda_nc_stat.misses++; /* record miss */
+ return((struct cnode *) 0);
+ }
+
+ coda_nc_stat.hits++;
+
+ /* put this entry at the end of the LRU */
+ CODA_NC_LRUREM(cncp);
+ CODA_NC_LRUINS(cncp, &coda_nc_lru);
+
+ /* move it to the front of the hash chain */
+ /* don't need to change the hash bucket length */
+ CODA_NC_HSHREM(cncp);
+ CODA_NC_HSHINS(cncp, &coda_nc_hash[hash]);
+
+ CODA_NC_DEBUG(CODA_NC_LOOKUP,
+ printf("lookup: dcp %p, name %s, cred %p = cp %p\n",
+ dcp, name, cred, cncp->cp); )
+
+ return(cncp->cp);
+}
+
+static void
+coda_nc_remove(cncp, dcstat)
+ struct coda_cache *cncp;
+ enum dc_status dcstat;
+{
+ /*
+ * remove an entry -- vrele(cncp->dcp, cp), crfree(cred),
+ * remove it from it's hash chain, and
+ * place it at the head of the lru list.
+ */
+ CODA_NC_DEBUG(CODA_NC_REMOVE,
+ myprintf(("coda_nc_remove %s from parent %lx.%lx.%lx\n",
+ cncp->name, (cncp->dcp)->c_fid.Volume,
+ (cncp->dcp)->c_fid.Vnode, (cncp->dcp)->c_fid.Unique));)
+
+ CODA_NC_HSHREM(cncp);
+
+ CODA_NC_HSHNUL(cncp); /* have it be a null chain */
+ if ((dcstat == IS_DOWNCALL) && (CTOV(cncp->dcp)->v_usecount == 1)) {
+ cncp->dcp->c_flags |= C_PURGING;
+ }
+ vrele(CTOV(cncp->dcp));
+
+ if ((dcstat == IS_DOWNCALL) && (CTOV(cncp->cp)->v_usecount == 1)) {
+ cncp->cp->c_flags |= C_PURGING;
+ }
+ vrele(CTOV(cncp->cp));
+
+ crfree(cncp->cred);
+ bzero(DATA_PART(cncp),DATA_SIZE);
+
+ /* Put the null entry just after the least-recently-used entry */
+ /* LRU_TOP adjusts the pointer to point to the top of the structure. */
+ CODA_NC_LRUREM(cncp);
+ CODA_NC_LRUINS(cncp, LRU_TOP(coda_nc_lru.lru_prev));
+}
+
+/*
+ * Remove all entries with a parent which has the input fid.
+ */
+void
+coda_nc_zapParentfid(fid, dcstat)
+ ViceFid *fid;
+ enum dc_status dcstat;
+{
+ /* To get to a specific fid, we might either have another hashing
+ function or do a sequential search through the cache for the
+ appropriate entries. The later may be acceptable since I don't
+ think callbacks or whatever Case 1 covers are frequent occurences.
+ */
+ struct coda_cache *cncp, *ncncp;
+ int i;
+
+ if (coda_nc_use == 0) /* Cache is off */
+ return;
+
+ CODA_NC_DEBUG(CODA_NC_ZAPPFID,
+ myprintf(("ZapParent: fid 0x%lx, 0x%lx, 0x%lx \n",
+ fid->Volume, fid->Vnode, fid->Unique)); )
+
+ coda_nc_stat.zapPfids++;
+
+ for (i = 0; i < coda_nc_hashsize; i++) {
+
+ /*
+ * Need to save the hash_next pointer in case we remove the
+ * entry. remove causes hash_next to point to itself.
+ */
+
+ for (cncp = coda_nc_hash[i].hash_next;
+ cncp != (struct coda_cache *)&coda_nc_hash[i];
+ cncp = ncncp) {
+ ncncp = cncp->hash_next;
+ if ((cncp->dcp->c_fid.Volume == fid->Volume) &&
+ (cncp->dcp->c_fid.Vnode == fid->Vnode) &&
+ (cncp->dcp->c_fid.Unique == fid->Unique)) {
+ coda_nc_hash[i].length--; /* Used for tuning */
+ coda_nc_remove(cncp, dcstat);
+ }
+ }
+ }
+}
+
+
+/*
+ * Remove all entries which have the same fid as the input
+ */
+void
+coda_nc_zapfid(fid, dcstat)
+ ViceFid *fid;
+ enum dc_status dcstat;
+{
+ /* See comment for zapParentfid. This routine will be used
+ if attributes are being cached.
+ */
+ struct coda_cache *cncp, *ncncp;
+ int i;
+
+ if (coda_nc_use == 0) /* Cache is off */
+ return;
+
+ CODA_NC_DEBUG(CODA_NC_ZAPFID,
+ myprintf(("Zapfid: fid 0x%lx, 0x%lx, 0x%lx \n",
+ fid->Volume, fid->Vnode, fid->Unique)); )
+
+ coda_nc_stat.zapFids++;
+
+ for (i = 0; i < coda_nc_hashsize; i++) {
+ for (cncp = coda_nc_hash[i].hash_next;
+ cncp != (struct coda_cache *)&coda_nc_hash[i];
+ cncp = ncncp) {
+ ncncp = cncp->hash_next;
+ if ((cncp->cp->c_fid.Volume == fid->Volume) &&
+ (cncp->cp->c_fid.Vnode == fid->Vnode) &&
+ (cncp->cp->c_fid.Unique == fid->Unique)) {
+ coda_nc_hash[i].length--; /* Used for tuning */
+ coda_nc_remove(cncp, dcstat);
+ }
+ }
+ }
+}
+
+/*
+ * Remove all entries which match the fid and the cred
+ */
+void
+coda_nc_zapvnode(fid, cred, dcstat)
+ ViceFid *fid;
+ struct ucred *cred;
+ enum dc_status dcstat;
+{
+ /* See comment for zapfid. I don't think that one would ever
+ want to zap a file with a specific cred from the kernel.
+ We'll leave this one unimplemented.
+ */
+ if (coda_nc_use == 0) /* Cache is off */
+ return;
+
+ CODA_NC_DEBUG(CODA_NC_ZAPVNODE,
+ myprintf(("Zapvnode: fid 0x%lx, 0x%lx, 0x%lx cred %p\n",
+ fid->Volume, fid->Vnode, fid->Unique, cred)); )
+
+}
+
+/*
+ * Remove all entries which have the (dir vnode, name) pair
+ */
+void
+coda_nc_zapfile(dcp, name, namelen)
+ struct cnode *dcp;
+ const char *name;
+ int namelen;
+{
+ /* use the hash function to locate the file, then zap all
+ entries of it regardless of the cred.
+ */
+ struct coda_cache *cncp;
+ int hash;
+
+ if (coda_nc_use == 0) /* Cache is off */
+ return;
+
+ CODA_NC_DEBUG(CODA_NC_ZAPFILE,
+ myprintf(("Zapfile: dcp %p name %s \n",
+ dcp, name)); )
+
+ if (namelen > CODA_NC_NAMELEN) {
+ coda_nc_stat.long_remove++; /* record stats */
+ return;
+ }
+
+ coda_nc_stat.zapFile++;
+
+ hash = CODA_NC_HASH(name, namelen, dcp);
+ cncp = coda_nc_find(dcp, name, namelen, 0, hash);
+
+ while (cncp) {
+ coda_nc_hash[hash].length--; /* Used for tuning */
+
+ coda_nc_remove(cncp, NOT_DOWNCALL);
+ cncp = coda_nc_find(dcp, name, namelen, 0, hash);
+ }
+}
+
+/*
+ * Remove all the entries for a particular user. Used when tokens expire.
+ * A user is determined by his/her effective user id (id_uid).
+ */
+void
+coda_nc_purge_user(uid, dcstat)
+ vuid_t uid;
+ enum dc_status dcstat;
+{
+ /*
+ * I think the best approach is to go through the entire cache
+ * via HASH or whatever and zap all entries which match the
+ * input cred. Or just flush the whole cache. It might be
+ * best to go through on basis of LRU since cache will almost
+ * always be full and LRU is more straightforward.
+ */
+
+ struct coda_cache *cncp, *ncncp;
+ int hash;
+
+ if (coda_nc_use == 0) /* Cache is off */
+ return;
+
+ CODA_NC_DEBUG(CODA_NC_PURGEUSER,
+ myprintf(("ZapDude: uid %x\n", uid)); )
+ coda_nc_stat.zapUsers++;
+
+ for (cncp = CODA_NC_LRUGET(coda_nc_lru);
+ cncp != (struct coda_cache *)(&coda_nc_lru);
+ cncp = ncncp) {
+ ncncp = CODA_NC_LRUGET(*cncp);
+
+ if ((CODA_NC_VALID(cncp)) &&
+ ((cncp->cred)->cr_uid == uid)) {
+ /* Seems really ugly, but we have to decrement the appropriate
+ hash bucket length here, so we have to find the hash bucket
+ */
+ hash = CODA_NC_HASH(cncp->name, cncp->namelen, cncp->dcp);
+ coda_nc_hash[hash].length--; /* For performance tuning */
+
+ coda_nc_remove(cncp, dcstat);
+ }
+ }
+}
+
+/*
+ * Flush the entire name cache. In response to a flush of the Venus cache.
+ */
+void
+coda_nc_flush(dcstat)
+ enum dc_status dcstat;
+{
+ /* One option is to deallocate the current name cache and
+ call init to start again. Or just deallocate, then rebuild.
+ Or again, we could just go through the array and zero the
+ appropriate fields.
+ */
+
+ /*
+ * Go through the whole lru chain and kill everything as we go.
+ * I don't use remove since that would rebuild the lru chain
+ * as it went and that seemed unneccesary.
+ */
+ struct coda_cache *cncp;
+ int i;
+
+ if (coda_nc_use == 0) /* Cache is off */
+ return;
+
+ coda_nc_stat.Flushes++;
+
+ for (cncp = CODA_NC_LRUGET(coda_nc_lru);
+ cncp != (struct coda_cache *)&coda_nc_lru;
+ cncp = CODA_NC_LRUGET(*cncp)) {
+ if (CODA_NC_VALID(cncp)) {
+
+ CODA_NC_HSHREM(cncp); /* only zero valid nodes */
+ CODA_NC_HSHNUL(cncp);
+ if ((dcstat == IS_DOWNCALL)
+ && (CTOV(cncp->dcp)->v_usecount == 1))
+ {
+ cncp->dcp->c_flags |= C_PURGING;
+ }
+ vrele(CTOV(cncp->dcp));
+
+ if (CTOV(cncp->cp)->v_flag & VTEXT) {
+ if (coda_vmflush(cncp->cp))
+ CODADEBUG(CODA_FLUSH,
+ myprintf(("coda_nc_flush: (%lx.%lx.%lx) busy\n", cncp->cp->c_fid.Volume, cncp->cp->c_fid.Vnode, cncp->cp->c_fid.Unique)); )
+ }
+
+ if ((dcstat == IS_DOWNCALL)
+ && (CTOV(cncp->cp)->v_usecount == 1))
+ {
+ cncp->cp->c_flags |= C_PURGING;
+ }
+ vrele(CTOV(cncp->cp));
+
+ crfree(cncp->cred);
+ bzero(DATA_PART(cncp),DATA_SIZE);
+ }
+ }
+
+ for (i = 0; i < coda_nc_hashsize; i++)
+ coda_nc_hash[i].length = 0;
+}
+
+/*
+ * Debugging routines
+ */
+
+/*
+ * This routine should print out all the hash chains to the console.
+ */
+void
+print_coda_nc(void)
+{
+ int hash;
+ struct coda_cache *cncp;
+
+ for (hash = 0; hash < coda_nc_hashsize; hash++) {
+ myprintf(("\nhash %d\n",hash));
+
+ for (cncp = coda_nc_hash[hash].hash_next;
+ cncp != (struct coda_cache *)&coda_nc_hash[hash];
+ cncp = cncp->hash_next) {
+ myprintf(("cp %p dcp %p cred %p name %s\n",
+ cncp->cp, cncp->dcp,
+ cncp->cred, cncp->name));
+ }
+ }
+}
+
+void
+coda_nc_gather_stats(void)
+{
+ int i, max = 0, sum = 0, temp, zeros = 0, ave, n;
+
+ for (i = 0; i < coda_nc_hashsize; i++) {
+ if (coda_nc_hash[i].length) {
+ sum += coda_nc_hash[i].length;
+ } else {
+ zeros++;
+ }
+
+ if (coda_nc_hash[i].length > max)
+ max = coda_nc_hash[i].length;
+ }
+
+ /*
+ * When computing the Arithmetic mean, only count slots which
+ * are not empty in the distribution.
+ */
+ coda_nc_stat.Sum_bucket_len = sum;
+ coda_nc_stat.Num_zero_len = zeros;
+ coda_nc_stat.Max_bucket_len = max;
+
+ if ((n = coda_nc_hashsize - zeros) > 0)
+ ave = sum / n;
+ else
+ ave = 0;
+
+ sum = 0;
+ for (i = 0; i < coda_nc_hashsize; i++) {
+ if (coda_nc_hash[i].length) {
+ temp = coda_nc_hash[i].length - ave;
+ sum += temp * temp;
+ }
+ }
+ coda_nc_stat.Sum2_bucket_len = sum;
+}
+
+/*
+ * The purpose of this routine is to allow the hash and cache sizes to be
+ * changed dynamically. This should only be used in controlled environments,
+ * it makes no effort to lock other users from accessing the cache while it
+ * is in an improper state (except by turning the cache off).
+ */
+int
+coda_nc_resize(hashsize, heapsize, dcstat)
+ int hashsize, heapsize;
+ enum dc_status dcstat;
+{
+ if ((hashsize % 2) || (heapsize % 2)) { /* Illegal hash or cache sizes */
+ return(EINVAL);
+ }
+
+ coda_nc_use = 0; /* Turn the cache off */
+
+ coda_nc_flush(dcstat); /* free any cnodes in the cache */
+
+ /* WARNING: free must happen *before* size is reset */
+ CODA_FREE(coda_nc_heap,TOTAL_CACHE_SIZE);
+ CODA_FREE(coda_nc_hash,TOTAL_HASH_SIZE);
+
+ coda_nc_hashsize = hashsize;
+ coda_nc_size = heapsize;
+
+ coda_nc_init(); /* Set up a cache with the new size */
+
+ coda_nc_use = 1; /* Turn the cache back on */
+ return(0);
+}
+
+#ifdef DEBUG
+char coda_nc_name_buf[CODA_MAXNAMLEN+1];
+
+void
+coda_nc_name(struct cnode *cp)
+{
+ struct coda_cache *cncp, *ncncp;
+ int i;
+
+ if (coda_nc_use == 0) /* Cache is off */
+ return;
+
+ for (i = 0; i < coda_nc_hashsize; i++) {
+ for (cncp = coda_nc_hash[i].hash_next;
+ cncp != (struct coda_cache *)&coda_nc_hash[i];
+ cncp = ncncp) {
+ ncncp = cncp->hash_next;
+ if (cncp->cp == cp) {
+ bcopy(cncp->name, coda_nc_name_buf, cncp->namelen);
+ coda_nc_name_buf[cncp->namelen] = 0;
+ printf(" is %s (%p,%p)@%p",
+ coda_nc_name_buf, cncp->cp, cncp->dcp, cncp);
+ }
+
+ }
+ }
+}
+#endif
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