Update vfs_cache.c to use the <sys/queue.h> macros. This makes it easier
to read, but doesn't change the speed. Reviewed by: phk Obtained from: via NetBSD
This commit is contained in:
Poul-Henning Kamp
parent
7cd21d1909
commit
30f467d84a
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=6928
@ -30,8 +30,8 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)vfs_cache.c 8.1 (Berkeley) 6/10/93
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* $Id: vfs_cache.c,v 1.3 1994/08/02 07:43:15 davidg Exp $
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* @(#)vfs_cache.c 8.3 (Berkeley) 8/22/94
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* $Id$
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*/
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#include <sys/param.h>
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@ -64,10 +64,10 @@
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/*
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* Structures associated with name cacheing.
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*/
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struct namecache **nchashtbl;
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LIST_HEAD(nchashhead, namecache) *nchashtbl; /* Hash Table */
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u_long nchash; /* size of hash table - 1 */
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long numcache; /* number of cache entries allocated */
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struct namecache *nchhead, **nchtail; /* LRU chain pointers */
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TAILQ_HEAD(, namecache) nclruhead; /* LRU chain */
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struct nchstats nchstats; /* cache effectiveness statistics */
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int doingcache = 1; /* 1 => enable the cache */
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@ -92,28 +92,46 @@ cache_lookup(dvp, vpp, cnp)
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struct vnode **vpp;
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struct componentname *cnp;
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{
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register struct namecache *ncp, *ncq, **ncpp;
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register struct namecache *ncp,*nnp;
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register struct nchashhead *ncpp;
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if (!doingcache)
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if (!doingcache) {
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cnp->cn_flags &= ~MAKEENTRY;
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return (0);
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}
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if (cnp->cn_namelen > NCHNAMLEN) {
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nchstats.ncs_long++;
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cnp->cn_flags &= ~MAKEENTRY;
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return (0);
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}
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ncpp = &nchashtbl[cnp->cn_hash & nchash];
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for (ncp = *ncpp; ncp; ncp = ncp->nc_forw) {
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for (ncp = ncpp->lh_first; ncp != 0; ncp = nnp) {
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if (ncp->nc_dvp == dvp &&
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ncp->nc_dvpid == dvp->v_id &&
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ncp->nc_nlen == cnp->cn_namelen &&
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!bcmp(ncp->nc_name, cnp->cn_nameptr, (u_int)ncp->nc_nlen))
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break;
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nnp = ncp->nc_hash.le_next;
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#ifdef not_yet_phk
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/*
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* if not already last and one of the vp's are invalid,
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* move to head of LRU
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*/
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if ((ncp->nc_lru.tqe_next != 0) &&
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( (ncp->nc_dvpid != ncp->nc_dvp->v_id) ||
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(ncp->nc_vp && (ncp->nc_vpid != ncp->nc_vp->v_id)))) {
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LIST_REMOVE(ncp, nc_hash);
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ncp->nc_hash.le_prev = 0;
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TAILQ_REMOVE(&nclruhead, ncp, nc_lru);
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TAILQ_INSERT_HEAD(&nclruhead, ncp, nc_lru);
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}
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#endif /* not_yet_phk */
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}
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if (ncp == NULL) {
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if (ncp == 0) {
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nchstats.ncs_miss++;
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return (0);
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}
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if (!(cnp->cn_flags & MAKEENTRY)) {
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if ((cnp->cn_flags & MAKEENTRY) == 0) {
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nchstats.ncs_badhits++;
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} else if (ncp->nc_vp == NULL) {
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if (cnp->cn_nameiop != CREATE) {
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@ -122,15 +140,9 @@ cache_lookup(dvp, vpp, cnp)
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* Move this slot to end of LRU chain,
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* if not already there.
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*/
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if (ncp->nc_nxt) {
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/* remove from LRU chain */
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*ncp->nc_prev = ncp->nc_nxt;
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ncp->nc_nxt->nc_prev = ncp->nc_prev;
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/* and replace at end of it */
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ncp->nc_nxt = NULL;
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ncp->nc_prev = nchtail;
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*nchtail = ncp;
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nchtail = &ncp->nc_nxt;
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if (ncp->nc_lru.tqe_next != 0) {
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TAILQ_REMOVE(&nclruhead, ncp, nc_lru);
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TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru);
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}
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return (ENOENT);
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}
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@ -141,16 +153,14 @@ cache_lookup(dvp, vpp, cnp)
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/*
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* move this slot to end of LRU chain, if not already there
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*/
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if (ncp->nc_nxt) {
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/* remove from LRU chain */
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*ncp->nc_prev = ncp->nc_nxt;
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ncp->nc_nxt->nc_prev = ncp->nc_prev;
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/* and replace at end of it */
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ncp->nc_nxt = NULL;
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ncp->nc_prev = nchtail;
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*nchtail = ncp;
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nchtail = &ncp->nc_nxt;
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if (ncp->nc_lru.tqe_next != 0) {
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TAILQ_REMOVE(&nclruhead, ncp, nc_lru);
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TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru);
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}
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#ifdef not_yet_phk
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/* Touch the parent vnode */
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vtouch(ncp->nc_dvp);
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#endif /* not_yet_phk */
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*vpp = ncp->nc_vp;
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return (-1);
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}
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@ -160,30 +170,10 @@ cache_lookup(dvp, vpp, cnp)
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* the cache entry is invalid, or otherwise don't
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* want cache entry to exist.
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*/
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/* remove from LRU chain */
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ncq = ncp->nc_nxt;
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if (ncq)
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ncq->nc_prev = ncp->nc_prev;
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else
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nchtail = ncp->nc_prev;
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*ncp->nc_prev = ncq;
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/* remove from hash chain */
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ncq = ncp->nc_forw;
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if (ncq)
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ncq->nc_back = ncp->nc_back;
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*ncp->nc_back = ncq;
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/* and make a dummy hash chain */
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ncp->nc_forw = NULL;
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ncp->nc_back = NULL;
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/* insert at head of LRU list (first to grab) */
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ncq = nchhead;
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if (ncq)
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ncq->nc_prev = &ncp->nc_nxt;
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else
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nchtail = &ncp->nc_nxt;
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nchhead = ncp;
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ncp->nc_nxt = ncq;
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ncp->nc_prev = &nchhead;
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TAILQ_REMOVE(&nclruhead, ncp, nc_lru);
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LIST_REMOVE(ncp, nc_hash);
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ncp->nc_hash.le_prev = 0;
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TAILQ_INSERT_HEAD(&nclruhead, ncp, nc_lru);
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return (0);
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}
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@ -196,7 +186,8 @@ cache_enter(dvp, vp, cnp)
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struct vnode *vp;
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struct componentname *cnp;
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{
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register struct namecache *ncp, *ncq, **ncpp;
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register struct namecache *ncp;
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register struct nchashhead *ncpp;
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#ifdef DIAGNOSTIC
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if (cnp->cn_namelen > NCHNAMLEN)
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@ -212,27 +203,14 @@ cache_enter(dvp, vp, cnp)
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malloc((u_long)sizeof *ncp, M_CACHE, M_WAITOK);
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bzero((char *)ncp, sizeof *ncp);
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numcache++;
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} else if (!nchhead) {
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return;
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} else {
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ncp = nchhead;
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/* remove from lru chain */
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ncq = ncp->nc_nxt;
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if (ncq)
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ncq->nc_prev = ncp->nc_prev;
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else
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nchtail = ncp->nc_prev;
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*ncp->nc_prev = ncq;
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/* remove from old hash chain, if on one */
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if (ncp->nc_back) {
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ncq = ncp->nc_forw;
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if (ncq)
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ncq->nc_back = ncp->nc_back;
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*ncp->nc_back = ncq;
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ncp->nc_forw = NULL;
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ncp->nc_back = NULL;
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} else if (ncp = nclruhead.tqh_first) {
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TAILQ_REMOVE(&nclruhead, ncp, nc_lru);
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if (ncp->nc_hash.le_prev != 0) {
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LIST_REMOVE(ncp, nc_hash);
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ncp->nc_hash.le_prev = 0;
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}
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}
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} else
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return;
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/* grab the vnode we just found */
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ncp->nc_vp = vp;
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if (vp)
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@ -244,19 +222,9 @@ cache_enter(dvp, vp, cnp)
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ncp->nc_dvpid = dvp->v_id;
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ncp->nc_nlen = cnp->cn_namelen;
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bcopy(cnp->cn_nameptr, ncp->nc_name, (unsigned)ncp->nc_nlen);
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/* link at end of lru chain */
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ncp->nc_nxt = NULL;
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ncp->nc_prev = nchtail;
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*nchtail = ncp;
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nchtail = &ncp->nc_nxt;
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/* and insert on hash chain */
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TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru);
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ncpp = &nchashtbl[cnp->cn_hash & nchash];
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ncq = *ncpp;
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if (ncq)
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ncq->nc_back = &ncp->nc_forw;
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ncp->nc_forw = ncq;
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ncp->nc_back = ncpp;
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*ncpp = ncp;
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LIST_INSERT_HEAD(ncpp, ncp, nc_hash);
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}
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/*
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@ -266,7 +234,7 @@ void
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nchinit()
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{
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nchtail = &nchhead;
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TAILQ_INIT(&nclruhead);
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nchashtbl = hashinit(desiredvnodes, M_CACHE, &nchash);
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}
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@ -278,13 +246,14 @@ void
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cache_purge(vp)
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struct vnode *vp;
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{
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struct namecache *ncp, **ncpp;
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struct namecache *ncp;
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struct nchashhead *ncpp;
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vp->v_id = ++nextvnodeid;
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if (nextvnodeid != 0)
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return;
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for (ncpp = &nchashtbl[nchash]; ncpp >= nchashtbl; ncpp--) {
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for (ncp = *ncpp; ncp; ncp = ncp->nc_forw) {
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for (ncp = ncpp->lh_first; ncp != 0; ncp = ncp->nc_hash.le_next) {
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ncp->nc_vpid = 0;
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ncp->nc_dvpid = 0;
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}
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@ -306,39 +275,21 @@ cache_purgevfs(mp)
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{
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register struct namecache *ncp, *nxtcp;
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for (ncp = nchhead; ncp; ncp = nxtcp) {
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for (ncp = nclruhead.tqh_first; ncp != 0; ncp = nxtcp) {
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if (ncp->nc_dvp == NULL || ncp->nc_dvp->v_mount != mp) {
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nxtcp = ncp->nc_nxt;
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nxtcp = ncp->nc_lru.tqe_next;
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continue;
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}
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/* free the resources we had */
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ncp->nc_vp = NULL;
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ncp->nc_dvp = NULL;
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/* remove from old hash chain, if on one */
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if (ncp->nc_back) {
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nxtcp = ncp->nc_forw;
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if (nxtcp)
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nxtcp->nc_back = ncp->nc_back;
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*ncp->nc_back = nxtcp;
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ncp->nc_forw = NULL;
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ncp->nc_back = NULL;
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TAILQ_REMOVE(&nclruhead, ncp, nc_lru);
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if (ncp->nc_hash.le_prev != 0) {
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LIST_REMOVE(ncp, nc_hash);
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ncp->nc_hash.le_prev = 0;
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}
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/* delete this entry from LRU chain */
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nxtcp = ncp->nc_nxt;
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if (nxtcp)
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nxtcp->nc_prev = ncp->nc_prev;
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else
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nchtail = ncp->nc_prev;
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*ncp->nc_prev = nxtcp;
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/* cause rescan of list, it may have altered */
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/* also put the now-free entry at head of LRU */
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nxtcp = nchhead;
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if (nxtcp)
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nxtcp->nc_prev = &ncp->nc_nxt;
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else
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nchtail = &ncp->nc_nxt;
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nchhead = ncp;
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ncp->nc_nxt = nxtcp;
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ncp->nc_prev = &nchhead;
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nxtcp = nclruhead.tqh_first;
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TAILQ_INSERT_HEAD(&nclruhead, ncp, nc_lru);
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}
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}
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@ -31,12 +31,14 @@
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* SUCH DAMAGE.
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*
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* @(#)namei.h 8.2 (Berkeley) 1/4/94
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* $Id: namei.h,v 1.2 1994/08/02 07:53:18 davidg Exp $
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* $Id: namei.h,v 1.3 1994/09/27 20:33:41 phk Exp $
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*/
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#ifndef _SYS_NAMEI_H_
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#define _SYS_NAMEI_H_
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#include <sys/queue.h>
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/*
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* Encapsulation of namei parameters.
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*/
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@ -155,10 +157,8 @@ struct nameidata {
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#define NCHNAMLEN 31 /* maximum name segment length we bother with */
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struct namecache {
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struct namecache *nc_forw; /* hash chain */
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struct namecache **nc_back; /* hash chain */
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struct namecache *nc_nxt; /* LRU chain */
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struct namecache **nc_prev; /* LRU chain */
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LIST_ENTRY(namecache) nc_hash; /* hash chain */
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TAILQ_ENTRY(namecache) nc_lru; /* LRU chain */
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struct vnode *nc_dvp; /* vnode of parent of name */
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u_long nc_dvpid; /* capability number of nc_dvp */
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struct vnode *nc_vp; /* vnode the name refers to */
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