256 lines
6.8 KiB
C
256 lines
6.8 KiB
C
/*-
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* Copyright (c) 2001 Dag-Erling Coïdan Smørgrav
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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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* in this position and unchanged.
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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. 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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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/sysctl.h>
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#include <sys/vnode.h>
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#include <fs/pseudofs/pseudofs.h>
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#include <fs/pseudofs/pseudofs_internal.h>
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static MALLOC_DEFINE(M_PFSVNCACHE, "pfs_vncache", "pseudofs vnode cache");
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static struct mtx pfs_vncache_mutex;
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struct pfs_vdata *pfs_vncache;
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static void pfs_exit(struct proc *p);
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SYSCTL_NODE(_vfs_pfs, OID_AUTO, vncache, CTLFLAG_RW, 0,
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"pseudofs vnode cache");
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static int pfs_vncache_entries;
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SYSCTL_INT(_vfs_pfs_vncache, OID_AUTO, entries, CTLFLAG_RD,
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&pfs_vncache_entries, 0,
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"number of entries in the vnode cache");
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static int pfs_vncache_maxentries;
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SYSCTL_INT(_vfs_pfs_vncache, OID_AUTO, maxentries, CTLFLAG_RD,
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&pfs_vncache_maxentries, 0,
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"highest number of entries in the vnode cache");
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static int pfs_vncache_hits;
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SYSCTL_INT(_vfs_pfs_vncache, OID_AUTO, hits, CTLFLAG_RD,
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&pfs_vncache_hits, 0,
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"number of cache hits since initialization");
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static int pfs_vncache_misses;
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SYSCTL_INT(_vfs_pfs_vncache, OID_AUTO, misses, CTLFLAG_RD,
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&pfs_vncache_misses, 0,
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"number of cache misses since initialization");
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extern vop_t **pfs_vnodeop_p;
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/*
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* Initialize vnode cache
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*/
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void
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pfs_vncache_load(void)
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{
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mtx_init(&pfs_vncache_mutex, "pseudofs_vncache", MTX_DEF|MTX_RECURSE);
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/* XXX at_exit() can fail with ENOMEN */
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at_exit(pfs_exit);
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}
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/*
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* Tear down vnode cache
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*/
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void
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pfs_vncache_unload(void)
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{
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rm_at_exit(pfs_exit);
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if (pfs_vncache_entries != 0)
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printf("pfs_vncache_unload(): %d entries remaining\n",
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pfs_vncache_entries);
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mtx_destroy(&pfs_vncache_mutex);
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}
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/*
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* Allocate a vnode
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*/
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int
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pfs_vncache_alloc(struct mount *mp, struct vnode **vpp,
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struct pfs_node *pn, pid_t pid)
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{
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struct pfs_vdata *pvd;
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int error;
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/* see if the vnode is in the cache */
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/* XXX linear search... not very efficient */
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mtx_lock(&pfs_vncache_mutex);
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for (pvd = pfs_vncache; pvd; pvd = pvd->pvd_next) {
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if (pvd->pvd_pn == pn && pvd->pvd_pid == pid) {
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if (vget(pvd->pvd_vnode, 0, curthread) == 0) {
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++pfs_vncache_hits;
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*vpp = pvd->pvd_vnode;
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mtx_unlock(&pfs_vncache_mutex);
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return (0);
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}
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/* XXX if this can happen, we're in trouble */
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break;
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}
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}
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mtx_unlock(&pfs_vncache_mutex);
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++pfs_vncache_misses;
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/* nope, get a new one */
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MALLOC(pvd, struct pfs_vdata *, sizeof *pvd, M_PFSVNCACHE, M_WAITOK);
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if (++pfs_vncache_entries > pfs_vncache_maxentries)
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pfs_vncache_maxentries = pfs_vncache_entries;
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error = getnewvnode(VT_PSEUDOFS, mp, pfs_vnodeop_p, vpp);
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if (error)
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return (error);
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pvd->pvd_pn = pn;
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pvd->pvd_pid = pid;
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(*vpp)->v_data = pvd;
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switch (pn->pn_type) {
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case pfstype_root:
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(*vpp)->v_flag = VROOT;
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#if 0
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printf("root vnode allocated\n");
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#endif
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/* fall through */
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case pfstype_dir:
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case pfstype_this:
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case pfstype_parent:
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case pfstype_procdir:
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(*vpp)->v_type = VDIR;
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break;
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case pfstype_file:
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(*vpp)->v_type = VREG;
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break;
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case pfstype_symlink:
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(*vpp)->v_type = VLNK;
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break;
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case pfstype_none:
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KASSERT(0, ("pfs_vncache_alloc called for null node\n"));
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default:
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panic("%s has unexpected type: %d", pn->pn_name, pn->pn_type);
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}
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pvd->pvd_vnode = *vpp;
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mtx_lock(&pfs_vncache_mutex);
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pvd->pvd_prev = NULL;
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pvd->pvd_next = pfs_vncache;
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if (pvd->pvd_next)
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pvd->pvd_next->pvd_prev = pvd;
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pfs_vncache = pvd;
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mtx_unlock(&pfs_vncache_mutex);
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return (0);
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}
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/*
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* Free a vnode
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*/
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int
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pfs_vncache_free(struct vnode *vp)
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{
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struct pfs_vdata *pvd;
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mtx_lock(&pfs_vncache_mutex);
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pvd = (struct pfs_vdata *)vp->v_data;
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KASSERT(pvd != NULL, ("pfs_vncache_free(): no vnode data\n"));
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if (pvd->pvd_next)
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pvd->pvd_next->pvd_prev = pvd->pvd_prev;
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if (pvd->pvd_prev)
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pvd->pvd_prev->pvd_next = pvd->pvd_next;
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else
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pfs_vncache = pvd->pvd_next;
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mtx_unlock(&pfs_vncache_mutex);
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--pfs_vncache_entries;
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FREE(pvd, M_PFSVNCACHE);
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vp->v_data = NULL;
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return (0);
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}
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/*
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* Free all vnodes associated with a defunct process
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*/
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static void
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pfs_exit(struct proc *p)
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{
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struct pfs_vdata *pvd, *prev;
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mtx_lock(&pfs_vncache_mutex);
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/*
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* The double loop is necessary because vgone() indirectly
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* calls pfs_vncache_free() which frees pvd, so we have to
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* backtrace one step every time we free a vnode.
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*/
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/* XXX linear search... not very efficient */
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for (pvd = pfs_vncache; pvd != NULL; pvd = pvd->pvd_next) {
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while (pvd != NULL && pvd->pvd_pid == p->p_pid) {
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prev = pvd->pvd_prev;
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vgone(pvd->pvd_vnode);
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pvd = prev ? prev->pvd_next : pfs_vncache;
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}
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}
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mtx_unlock(&pfs_vncache_mutex);
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}
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/*
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* Disable a pseudofs node, and free all vnodes associated with it
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*/
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int
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pfs_disable(struct pfs_node *pn)
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{
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struct pfs_vdata *pvd, *prev;
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if (pn->pn_flags & PFS_DISABLED)
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return (0);
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mtx_lock(&pfs_vncache_mutex);
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pn->pn_flags |= PFS_DISABLED;
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/* see the comment about the double loop in pfs_exit() */
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/* XXX linear search... not very efficient */
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for (pvd = pfs_vncache; pvd != NULL; pvd = pvd->pvd_next) {
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while (pvd != NULL && pvd->pvd_pn == pn) {
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prev = pvd->pvd_prev;
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vgone(pvd->pvd_vnode);
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pvd = prev ? prev->pvd_next : pfs_vncache;
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}
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}
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mtx_unlock(&pfs_vncache_mutex);
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return (0);
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}
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/*
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* Re-enable a disabled pseudofs node
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*/
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int
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pfs_enable(struct pfs_node *pn)
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{
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pn->pn_flags &= ~PFS_DISABLED;
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return (0);
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}
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