c398ae9734
- LOCKPARENT is no longer relevant for lookup(), relookup() or VOP_LOOKUP(). these now always return the parent vnode locked. namei() works as before. lookup() and various other paths no longer acquire vnode locks in the wrong order via vrele(). fixes PR 32535. as a nice side effect, path lookup is also up to 25% faster. - the above allows us to get rid of PDIRUNLOCK. - also get rid of WANTPARENT (just use LOCKPARENT and unlock it). - remove an assumption in layer_node_find() that all file systems implement a recursive VOP_LOCK() (unionfs doesn't). - require that all file systems supply vfs_vptofh and vfs_fhtovp routines. fill in eopnotsupp() for file systems that don't support being exported and remove the checks for NULL. (layerfs calls these without checking.) - in union_lookup1(), don't change refcounts in the ISDOTDOT case, just adjust which vnode is locked. fixes PR 33374. - apply fixes for ufs_rename() from ufs_vnops.c rev. 1.61 to ext2fs_rename().
254 lines
7.0 KiB
C
254 lines
7.0 KiB
C
/* $NetBSD: adlookup.c,v 1.9 2006/12/09 16:11:50 chs Exp $ */
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/*
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* Copyright (c) 1994 Christian E. Hopps
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* Copyright (c) 1996 Matthias Scheler
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Christian E. Hopps.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: adlookup.c,v 1.9 2006/12/09 16:11:50 chs Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/vnode.h>
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#include <sys/namei.h>
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#include <sys/mount.h>
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#include <sys/time.h>
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#include <sys/queue.h>
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#include <fs/adosfs/adosfs.h>
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#ifdef ADOSFS_EXACTMATCH
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#define strmatch(s1, l1, s2, l2, i) \
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((l1) == (l2) && memcmp((s1), (s2), (l1)) == 0)
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#else
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#define strmatch(s1, l1, s2, l2, i) \
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((l1) == (l2) && adoscaseequ((s1), (s2), (l1), (i)))
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#endif
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/*
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* adosfs lookup. enters with:
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* pvp (parent vnode) referenced and locked.
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* exit with:
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* target vp referenced and locked.
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* parent pvp locked.
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* special cases:
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* pvp == vp, just ref pvp, pvp already holds a ref and lock from
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* caller, this will not occur with RENAME or CREATE.
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*/
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int
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adosfs_lookup(v)
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void *v;
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{
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struct vop_lookup_args /* {
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struct vnode *a_dvp;
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struct vnode **a_vpp;
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struct componentname *a_cnp;
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} */ *sp = v;
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int nameiop, last, flags, error, nocache, i;
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struct componentname *cnp;
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struct vnode **vpp; /* place to store result */
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struct anode *ap; /* anode to find */
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struct vnode *vdp; /* vnode of search dir */
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struct anode *adp; /* anode of search dir */
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kauth_cred_t ucp; /* lookup credentials */
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u_long bn, plen, hval;
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const u_char *pelt;
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#ifdef ADOSFS_DIAGNOSTIC
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advopprint(sp);
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#endif
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cnp = sp->a_cnp;
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vdp = sp->a_dvp;
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adp = VTOA(vdp);
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vpp = sp->a_vpp;
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*vpp = NULL;
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ucp = cnp->cn_cred;
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nameiop = cnp->cn_nameiop;
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flags = cnp->cn_flags;
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last = flags & ISLASTCN;
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pelt = (const u_char *)cnp->cn_nameptr;
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plen = cnp->cn_namelen;
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nocache = 0;
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/*
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* Check accessiblity of directory.
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*/
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if ((error = VOP_ACCESS(vdp, VEXEC, ucp, cnp->cn_lwp)) != 0)
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return (error);
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if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) &&
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(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
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return (EROFS);
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/*
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* Before tediously performing a linear scan of the directory,
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* check the name cache to see if the directory/name pair
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* we are looking for is known already.
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*/
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if ((error = cache_lookup(vdp, vpp, cnp)) >= 0)
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return (error);
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/*
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* fake a '.'
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*/
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if (plen == 1 && pelt[0] == '.') {
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/* see special cases in prologue. */
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*vpp = vdp;
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goto found;
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}
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/*
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* fake a ".."
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*/
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if (flags & ISDOTDOT) {
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if (vdp->v_type == VDIR && (vdp->v_flag & VROOT))
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panic("adosfs .. attempted through root");
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/*
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* cannot get `..' while `vdp' is locked
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* e.g. procA holds lock on `..' and waits for `vdp'
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* we wait for `..' and hold lock on `vdp'. deadlock.
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* because `vdp' may have been achieved through symlink
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* fancy detection code that decreases the race
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* window size is not reasonably possible.
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*
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* basically unlock the parent, try and lock the child (..)
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* if that fails relock the parent (ignoring error) and
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* fail. Otherwise we have the child (..), attempt to
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* relock the parent. If that fails unlock the child (..)
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* and fail. Otherwise we have succeded.
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*
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*/
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VOP_UNLOCK(vdp, 0); /* race */
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error = VFS_VGET(vdp->v_mount, (ino_t)adp->pblock, vpp);
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vn_lock(vdp, LK_EXCLUSIVE | LK_RETRY);
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if (error) {
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*vpp = NULL;
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return (error);
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}
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goto found_lockdone;
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}
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/*
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* hash the name and grab the first block in chain
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* then walk the chain. if chain has not been fully
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* walked before, track the count in `tabi'
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*/
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hval = adoshash(pelt, plen, adp->ntabent, IS_INTER(adp->amp));
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bn = adp->tab[hval];
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i = min(adp->tabi[hval], 0);
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while (bn != 0) {
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if ((error = VFS_VGET(vdp->v_mount, (ino_t)bn, vpp
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)) != 0) {
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#ifdef ADOSFS_DIAGNOSTIC
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printf("[aget] %d)", error);
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#endif
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return(error);
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}
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ap = VTOA(*vpp);
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if (i <= 0) {
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if (--i < adp->tabi[hval])
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adp->tabi[hval] = i;
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/*
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* last header in chain lock count down by
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* negating it to positive
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*/
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if (ap->hashf == 0) {
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#ifdef DEBUG
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if (i != adp->tabi[hval])
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panic("adlookup: wrong chain count");
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#endif
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adp->tabi[hval] = -adp->tabi[hval];
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}
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}
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if (strmatch(pelt, plen, ap->name, strlen(ap->name),
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IS_INTER(adp->amp)))
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goto found;
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bn = ap->hashf;
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vput(*vpp);
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}
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*vpp = NULL;
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/*
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* not found
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*/
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if ((nameiop == CREATE || nameiop == RENAME) && last) {
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if (vdp->v_mount->mnt_flag & MNT_RDONLY)
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return (EROFS);
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if ((error = VOP_ACCESS(vdp, VWRITE, ucp, cnp->cn_lwp)) != 0) {
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#ifdef ADOSFS_DIAGNOSTIC
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printf("[VOP_ACCESS] %d)", error);
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#endif
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return (error);
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}
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cnp->cn_nameiop |= SAVENAME;
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#ifdef ADOSFS_DIAGNOSTIC
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printf("EJUSTRETURN)");
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#endif
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return(EJUSTRETURN);
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}
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if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
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cache_enter(vdp, NULL, cnp);
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#ifdef ADOSFS_DIAGNOSTIC
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printf("ENOENT)");
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#endif
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return(ENOENT);
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found:
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if (nameiop == DELETE && last) {
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if ((error = VOP_ACCESS(vdp, VWRITE, ucp, cnp->cn_lwp)) != 0) {
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if (vdp != *vpp)
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vput(*vpp);
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*vpp = NULL;
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return (error);
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}
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nocache = 1;
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}
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if (nameiop == RENAME && last) {
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if (vdp == *vpp)
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return(EISDIR);
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if ((error = VOP_ACCESS(vdp, VWRITE, ucp, cnp->cn_lwp)) != 0) {
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vput(*vpp);
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*vpp = NULL;
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return (error);
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}
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cnp->cn_flags |= SAVENAME;
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nocache = 1;
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}
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if (vdp == *vpp)
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VREF(vdp);
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found_lockdone:
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if ((cnp->cn_flags & MAKEENTRY) && nocache == 0)
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cache_enter(vdp, *vpp, cnp);
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#ifdef ADOSFS_DIAGNOSTIC
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printf("0)\n");
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#endif
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return(0);
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}
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