fix access-after-free bugs in dircache code by refcounting nfsdircache.
PR/26864.
This commit is contained in:
yamt
parent
0ea22c32fa
commit
e11d5e7c46
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@ -1,4 +1,4 @@
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/* $NetBSD: nfs_bio.c,v 1.119 2004/07/18 07:43:00 yamt Exp $ */
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/* $NetBSD: nfs_bio.c,v 1.120 2004/09/15 09:50:56 yamt Exp $ */
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/*
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* Copyright (c) 1989, 1993
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@ -35,7 +35,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: nfs_bio.c,v 1.119 2004/07/18 07:43:00 yamt Exp $");
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__KERNEL_RCSID(0, "$NetBSD: nfs_bio.c,v 1.120 2004/09/15 09:50:56 yamt Exp $");
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#include "opt_nfs.h"
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#include "opt_ddb.h"
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@ -282,6 +282,7 @@ diragain:
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if (uio->uio_offset != 0 &&
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ndp->dc_cookie == np->n_direofoffset) {
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nfs_putdircache(np, ndp);
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nfsstats.direofcache_hits++;
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return (0);
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}
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@ -299,6 +300,7 @@ diragain:
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* server. Punt and let the userland code
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* deal with it.
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*/
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nfs_putdircache(np, ndp);
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brelse(bp);
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if (error == NFSERR_BAD_COOKIE) {
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nfs_invaldircache(vp, 0);
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@ -317,6 +319,7 @@ diragain:
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*/
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if (np->n_direofoffset != 0 &&
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ndp->dc_blkcookie == np->n_direofoffset) {
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nfs_putdircache(np, ndp);
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brelse(bp);
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return (0);
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}
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@ -351,6 +354,7 @@ diragain:
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(unsigned long)uio->uio_offset,
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(unsigned long)NFS_GETCOOKIE(pdp));
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#endif
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nfs_putdircache(np, ndp);
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brelse(bp);
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nfs_invaldircache(vp, 0);
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nfs_vinvalbuf(vp, 0, cred, p, 0);
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@ -393,11 +397,13 @@ diragain:
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NFS_STASHCOOKIE32(pdp,
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nndp->dc_cookie32);
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}
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nfs_putdircache(np, nndp);
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}
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pdp = dp;
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dp = (struct dirent *)((caddr_t)dp + dp->d_reclen);
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enn++;
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}
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nfs_putdircache(np, ndp);
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/*
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* If the last requested entry was not the last in the
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@ -414,6 +420,7 @@ diragain:
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NFS_STASHCOOKIE32(pdp, nndp->dc_cookie32);
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curoff = nndp->dc_cookie32;
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}
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nfs_putdircache(np, nndp);
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} else
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curoff = bp->b_dcookie;
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@ -452,6 +459,7 @@ diragain:
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brelse(rabp);
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}
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}
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nfs_putdircache(np, nndp);
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got_buf = 1;
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break;
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default:
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@ -1,4 +1,4 @@
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/* $NetBSD: nfs_subs.c,v 1.134 2004/06/14 12:28:35 yamt Exp $ */
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/* $NetBSD: nfs_subs.c,v 1.135 2004/09/15 09:50:56 yamt Exp $ */
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/*
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* Copyright (c) 1989, 1993
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@ -70,7 +70,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: nfs_subs.c,v 1.134 2004/06/14 12:28:35 yamt Exp $");
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__KERNEL_RCSID(0, "$NetBSD: nfs_subs.c,v 1.135 2004/09/15 09:50:56 yamt Exp $");
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#include "fs_nfs.h"
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#include "opt_nfs.h"
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@ -1214,19 +1214,32 @@ nfs_dirhash(off)
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return sum;
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}
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#define _NFSDC_MTX(np) (&NFSTOV(np)->v_interlock)
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#define NFSDC_LOCK(np) simple_lock(_NFSDC_MTX(np))
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#define NFSDC_UNLOCK(np) simple_unlock(_NFSDC_MTX(np))
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#define NFSDC_ASSERT_LOCKED(np) LOCK_ASSERT(simple_lock_held(_NFSDC_MTX(np)))
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void
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nfs_initdircache(vp)
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struct vnode *vp;
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{
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struct nfsnode *np = VTONFS(vp);
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struct nfsdirhashhead *dircache;
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KASSERT(np->n_dircache == NULL);
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dircache = hashinit(NFS_DIRHASHSIZ, HASH_LIST, M_NFSDIROFF,
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M_WAITOK, &nfsdirhashmask);
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NFSDC_LOCK(np);
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if (np->n_dircache == NULL) {
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np->n_dircachesize = 0;
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np->n_dblkno = 1;
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np->n_dircache = hashinit(NFS_DIRHASHSIZ, HASH_LIST, M_NFSDIROFF,
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M_WAITOK, &nfsdirhashmask);
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np->n_dircache = dircache;
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dircache = NULL;
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TAILQ_INIT(&np->n_dirchain);
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}
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NFSDC_UNLOCK(np);
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if (dircache)
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hashdone(dircache, M_NFSDIROFF);
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}
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void
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@ -1234,16 +1247,83 @@ nfs_initdirxlatecookie(vp)
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struct vnode *vp;
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{
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struct nfsnode *np = VTONFS(vp);
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unsigned *dirgens;
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KASSERT(VFSTONFS(vp->v_mount)->nm_flag & NFSMNT_XLATECOOKIE);
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KASSERT(np->n_dirgens == NULL);
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MALLOC(np->n_dirgens, unsigned *,
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NFS_DIRHASHSIZ * sizeof (unsigned), M_NFSDIROFF, M_WAITOK);
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memset((caddr_t)np->n_dirgens, 0, NFS_DIRHASHSIZ * sizeof (unsigned));
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dirgens = malloc(NFS_DIRHASHSIZ * sizeof (unsigned), M_NFSDIROFF,
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M_WAITOK|M_ZERO);
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NFSDC_LOCK(np);
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if (np->n_dirgens == NULL) {
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np->n_dirgens = dirgens;
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dirgens = NULL;
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}
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NFSDC_UNLOCK(np);
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if (dirgens)
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free(dirgens, M_NFSDIROFF);
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}
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static struct nfsdircache dzero = {0, 0, {0, 0}, {0, 0}, 0, 0, 0};
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static const struct nfsdircache dzero;
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static void nfs_unlinkdircache __P((struct nfsnode *np, struct nfsdircache *));
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static void nfs_putdircache_unlocked __P((struct nfsnode *,
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struct nfsdircache *));
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static void
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nfs_unlinkdircache(np, ndp)
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struct nfsnode *np;
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struct nfsdircache *ndp;
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{
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NFSDC_ASSERT_LOCKED(np);
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KASSERT(ndp != &dzero);
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if (LIST_NEXT(ndp, dc_hash) == (void *)-1)
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return;
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TAILQ_REMOVE(&np->n_dirchain, ndp, dc_chain);
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LIST_REMOVE(ndp, dc_hash);
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LIST_NEXT(ndp, dc_hash) = (void *)-1; /* mark as unlinked */
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nfs_putdircache_unlocked(np, ndp);
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}
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void
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nfs_putdircache(np, ndp)
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struct nfsnode *np;
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struct nfsdircache *ndp;
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{
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int ref;
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if (ndp == &dzero)
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return;
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KASSERT(ndp->dc_refcnt > 0);
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NFSDC_LOCK(np);
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ref = --ndp->dc_refcnt;
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NFSDC_UNLOCK(np);
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if (ref == 0)
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free(ndp, M_NFSDIROFF);
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}
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static void
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nfs_putdircache_unlocked(np, ndp)
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struct nfsnode *np;
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struct nfsdircache *ndp;
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{
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int ref;
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NFSDC_ASSERT_LOCKED(np);
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if (ndp == &dzero)
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return;
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KASSERT(ndp->dc_refcnt > 0);
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ref = --ndp->dc_refcnt;
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if (ref == 0)
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free(ndp, M_NFSDIROFF);
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}
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struct nfsdircache *
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nfs_searchdircache(vp, off, do32, hashent)
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@ -1261,7 +1341,8 @@ nfs_searchdircache(vp, off, do32, hashent)
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* Zero is always a valid cookie.
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*/
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if (off == 0)
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return &dzero;
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/* LINTED const cast away */
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return (struct nfsdircache *)&dzero;
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if (!np->n_dircache)
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return NULL;
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@ -1281,6 +1362,8 @@ nfs_searchdircache(vp, off, do32, hashent)
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if (hashent)
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*hashent = (int)(ndhp - np->n_dircache);
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NFSDC_LOCK(np);
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if (do32) {
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LIST_FOREACH(ndp, ndhp, dc_hash) {
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if (ndp->dc_cookie32 == (u_int32_t)off) {
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@ -1289,10 +1372,11 @@ nfs_searchdircache(vp, off, do32, hashent)
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* start of a new block fetched from
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* the server.
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*/
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if (ndp->dc_blkno == -1) {
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if (ndp->dc_flags & NFSDC_INVALID) {
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ndp->dc_blkcookie = ndp->dc_cookie;
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ndp->dc_blkno = np->n_dblkno++;
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ndp->dc_entry = 0;
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ndp->dc_flags &= ~NFSDC_INVALID;
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}
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break;
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}
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@ -1303,6 +1387,9 @@ nfs_searchdircache(vp, off, do32, hashent)
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break;
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}
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}
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if (ndp != NULL)
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ndp->dc_refcnt++;
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NFSDC_UNLOCK(np);
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return ndp;
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}
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@ -1316,10 +1403,20 @@ nfs_enterdircache(vp, off, blkoff, en, blkno)
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{
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struct nfsnode *np = VTONFS(vp);
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struct nfsdirhashhead *ndhp;
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struct nfsdircache *ndp = NULL, *first;
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struct nfsdircache *ndp = NULL;
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struct nfsdircache *newndp = NULL;
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struct nfsmount *nmp = VFSTONFS(vp->v_mount);
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int hashent, gen, overwrite;
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/*
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* XXX refuse entries for offset 0. amd(8) erroneously sets
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* cookie 0 for the '.' entry, making this necessary. This
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* isn't so bad, as 0 is a special case anyway.
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*/
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if (off == 0)
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/* LINTED const cast away */
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return (struct nfsdircache *)&dzero;
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if (!np->n_dircache)
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/*
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* XXX would like to do this in nfs_nget but vtype
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@ -1330,34 +1427,34 @@ nfs_enterdircache(vp, off, blkoff, en, blkno)
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if ((nmp->nm_flag & NFSMNT_XLATECOOKIE) && !np->n_dirgens)
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nfs_initdirxlatecookie(vp);
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/*
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* XXX refuse entries for offset 0. amd(8) erroneously sets
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* cookie 0 for the '.' entry, making this necessary. This
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* isn't so bad, as 0 is a special case anyway.
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*/
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if (off == 0)
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return &dzero;
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retry:
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ndp = nfs_searchdircache(vp, off, 0, &hashent);
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if (ndp && ndp->dc_blkno != -1) {
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NFSDC_LOCK(np);
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if (ndp && (ndp->dc_flags & NFSDC_INVALID) == 0) {
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/*
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* Overwriting an old entry. Check if it's the same.
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* If so, just return. If not, remove the old entry.
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*/
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if (ndp->dc_blkcookie == blkoff && ndp->dc_entry == en)
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return ndp;
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TAILQ_REMOVE(&np->n_dirchain, ndp, dc_chain);
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LIST_REMOVE(ndp, dc_hash);
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FREE(ndp, M_NFSDIROFF);
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ndp = 0;
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goto done;
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nfs_unlinkdircache(np, ndp);
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nfs_putdircache_unlocked(np, ndp);
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ndp = NULL;
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}
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ndhp = &np->n_dircache[hashent];
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if (!ndp) {
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MALLOC(ndp, struct nfsdircache *, sizeof (*ndp), M_NFSDIROFF,
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M_WAITOK);
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if (newndp == NULL) {
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NFSDC_UNLOCK(np);
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newndp = malloc(sizeof(*ndp), M_NFSDIROFF, M_WAITOK);
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newndp->dc_refcnt = 1;
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LIST_NEXT(newndp, dc_hash) = (void *)-1;
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goto retry;
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}
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ndp = newndp;
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newndp = NULL;
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overwrite = 0;
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if (nmp->nm_flag & NFSMNT_XLATECOOKIE) {
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/*
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@ -1388,7 +1485,7 @@ nfs_enterdircache(vp, off, blkoff, en, blkno)
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ndp->dc_entry = en;
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if (overwrite)
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return ndp;
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goto done;
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/*
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* If the maximum directory cookie cache size has been reached
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@ -1398,15 +1495,19 @@ nfs_enterdircache(vp, off, blkoff, en, blkno)
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* loss.
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*/
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if (np->n_dircachesize == NFS_MAXDIRCACHE) {
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first = TAILQ_FIRST(&np->n_dirchain);
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TAILQ_REMOVE(&np->n_dirchain, first, dc_chain);
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LIST_REMOVE(first, dc_hash);
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FREE(first, M_NFSDIROFF);
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nfs_unlinkdircache(np, TAILQ_FIRST(&np->n_dirchain));
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} else
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np->n_dircachesize++;
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KASSERT(ndp->dc_refcnt == 1);
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LIST_INSERT_HEAD(ndhp, ndp, dc_hash);
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TAILQ_INSERT_TAIL(&np->n_dirchain, ndp, dc_chain);
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ndp->dc_refcnt++;
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done:
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KASSERT(ndp->dc_refcnt > 0);
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NFSDC_UNLOCK(np);
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if (newndp)
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nfs_putdircache(np, newndp);
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return ndp;
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}
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@ -1427,11 +1528,11 @@ nfs_invaldircache(vp, forcefree)
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if (!np->n_dircache)
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return;
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NFSDC_LOCK(np);
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if (!(nmp->nm_flag & NFSMNT_XLATECOOKIE) || forcefree) {
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while ((ndp = TAILQ_FIRST(&np->n_dirchain)) != 0) {
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TAILQ_REMOVE(&np->n_dirchain, ndp, dc_chain);
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LIST_REMOVE(ndp, dc_hash);
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FREE(ndp, M_NFSDIROFF);
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while ((ndp = TAILQ_FIRST(&np->n_dirchain)) != NULL) {
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KASSERT(!forcefree || ndp->dc_refcnt == 1);
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nfs_unlinkdircache(np, ndp);
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}
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np->n_dircachesize = 0;
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if (forcefree && np->n_dirgens) {
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@ -1439,12 +1540,12 @@ nfs_invaldircache(vp, forcefree)
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np->n_dirgens = NULL;
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}
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} else {
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TAILQ_FOREACH(ndp, &np->n_dirchain, dc_chain) {
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ndp->dc_blkno = -1;
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}
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TAILQ_FOREACH(ndp, &np->n_dirchain, dc_chain)
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ndp->dc_flags |= NFSDC_INVALID;
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}
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np->n_dblkno = 1;
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NFSDC_UNLOCK(np);
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}
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/*
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@ -1,4 +1,4 @@
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/* $NetBSD: nfs_var.h,v 1.45 2004/05/22 22:52:16 jonathan Exp $ */
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/* $NetBSD: nfs_var.h,v 1.46 2004/09/15 09:50:56 yamt Exp $ */
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/*-
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* Copyright (c) 1996 The NetBSD Foundation, Inc.
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@ -261,6 +261,7 @@ void nfs_initdircache __P((struct vnode *));
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void nfs_initdirxlatecookie __P((struct vnode *));
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struct nfsdircache *nfs_searchdircache __P((struct vnode *, off_t, int, int *));
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struct nfsdircache *nfs_enterdircache __P((struct vnode *, off_t, off_t, int, daddr_t));
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void nfs_putdircache __P((struct nfsnode *, struct nfsdircache *));
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void nfs_invaldircache __P((struct vnode *, int));
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void nfs_init __P((void));
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int nfsm_loadattrcache __P((struct vnode **, struct mbuf **, caddr_t *,
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@ -1,4 +1,4 @@
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/* $NetBSD: nfsnode.h,v 1.48 2004/08/24 20:09:44 yamt Exp $ */
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/* $NetBSD: nfsnode.h,v 1.49 2004/09/15 09:50:56 yamt Exp $ */
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/*
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* Copyright (c) 1989, 1993
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|
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@ -80,11 +80,15 @@ struct nfsdircache {
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off_t dc_blkcookie; /* Offset of block we're in */
|
||||
LIST_ENTRY(nfsdircache) dc_hash; /* Hash chain */
|
||||
TAILQ_ENTRY(nfsdircache) dc_chain; /* Least recently entered chn */
|
||||
u_int32_t dc_cookie32; /* Key for 64<->32 xlate case */
|
||||
daddr_t dc_blkno; /* Number of block we're in */
|
||||
u_int32_t dc_cookie32; /* Key for 64<->32 xlate case */
|
||||
int dc_entry; /* Entry number within block */
|
||||
int dc_refcnt; /* Reference count */
|
||||
int dc_flags; /* NFSDC_ flags */
|
||||
};
|
||||
|
||||
#define NFSDC_INVALID 1
|
||||
|
||||
|
||||
/*
|
||||
* The nfsnode is the nfs equivalent to ufs's inode. Any similarity
|
||||
|
|
|
|||
Loading…
Reference in New Issue