1 /*-
2 * Copyright (c) 2001 Dag-Erling Coïdan Smørgrav
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer
10 * in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * $FreeBSD: releng/5.0/sys/fs/pseudofs/pseudofs_vncache.c 105165 2002-10-15 18:51:02Z phk $
29 */
30
31 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/systm.h>
34 #include <sys/lock.h>
35 #include <sys/malloc.h>
36 #include <sys/mutex.h>
37 #include <sys/proc.h>
38 #include <sys/sysctl.h>
39 #include <sys/vnode.h>
40
41 #include <fs/pseudofs/pseudofs.h>
42 #include <fs/pseudofs/pseudofs_internal.h>
43
44 static MALLOC_DEFINE(M_PFSVNCACHE, "pfs_vncache", "pseudofs vnode cache");
45
46 static struct mtx pfs_vncache_mutex;
47 static struct pfs_vdata *pfs_vncache;
48 static void pfs_exit(struct proc *p);
49
50 SYSCTL_NODE(_vfs_pfs, OID_AUTO, vncache, CTLFLAG_RW, 0,
51 "pseudofs vnode cache");
52
53 static int pfs_vncache_entries;
54 SYSCTL_INT(_vfs_pfs_vncache, OID_AUTO, entries, CTLFLAG_RD,
55 &pfs_vncache_entries, 0,
56 "number of entries in the vnode cache");
57
58 static int pfs_vncache_maxentries;
59 SYSCTL_INT(_vfs_pfs_vncache, OID_AUTO, maxentries, CTLFLAG_RD,
60 &pfs_vncache_maxentries, 0,
61 "highest number of entries in the vnode cache");
62
63 static int pfs_vncache_hits;
64 SYSCTL_INT(_vfs_pfs_vncache, OID_AUTO, hits, CTLFLAG_RD,
65 &pfs_vncache_hits, 0,
66 "number of cache hits since initialization");
67
68 static int pfs_vncache_misses;
69 SYSCTL_INT(_vfs_pfs_vncache, OID_AUTO, misses, CTLFLAG_RD,
70 &pfs_vncache_misses, 0,
71 "number of cache misses since initialization");
72
73 extern vop_t **pfs_vnodeop_p;
74
75 /*
76 * Initialize vnode cache
77 */
78 void
79 pfs_vncache_load(void)
80 {
81 mtx_init(&pfs_vncache_mutex, "pseudofs_vncache", NULL,
82 MTX_DEF | MTX_RECURSE);
83 /* XXX at_exit() can fail with ENOMEN */
84 at_exit(pfs_exit);
85 }
86
87 /*
88 * Tear down vnode cache
89 */
90 void
91 pfs_vncache_unload(void)
92 {
93 rm_at_exit(pfs_exit);
94 if (pfs_vncache_entries != 0)
95 printf("pfs_vncache_unload(): %d entries remaining\n",
96 pfs_vncache_entries);
97 mtx_destroy(&pfs_vncache_mutex);
98 }
99
100 /*
101 * Allocate a vnode
102 */
103 int
104 pfs_vncache_alloc(struct mount *mp, struct vnode **vpp,
105 struct pfs_node *pn, pid_t pid)
106 {
107 struct pfs_vdata *pvd;
108 int error;
109
110 /*
111 * See if the vnode is in the cache.
112 * XXX linear search is not very efficient.
113 */
114 mtx_lock(&pfs_vncache_mutex);
115 for (pvd = pfs_vncache; pvd; pvd = pvd->pvd_next) {
116 if (pvd->pvd_pn == pn && pvd->pvd_pid == pid) {
117 if (vget(pvd->pvd_vnode, 0, curthread) == 0) {
118 ++pfs_vncache_hits;
119 *vpp = pvd->pvd_vnode;
120 mtx_unlock(&pfs_vncache_mutex);
121 /* XXX see comment at top of pfs_lookup() */
122 cache_purge(*vpp);
123 vn_lock(*vpp, LK_RETRY | LK_EXCLUSIVE,
124 curthread);
125 return (0);
126 }
127 /* XXX if this can happen, we're in trouble */
128 break;
129 }
130 }
131 mtx_unlock(&pfs_vncache_mutex);
132 ++pfs_vncache_misses;
133
134 /* nope, get a new one */
135 MALLOC(pvd, struct pfs_vdata *, sizeof *pvd, M_PFSVNCACHE, M_WAITOK);
136 if (++pfs_vncache_entries > pfs_vncache_maxentries)
137 pfs_vncache_maxentries = pfs_vncache_entries;
138 error = getnewvnode("pseudofs", mp, pfs_vnodeop_p, vpp);
139 if (error) {
140 FREE(pvd, M_PFSVNCACHE);
141 return (error);
142 }
143 pvd->pvd_pn = pn;
144 pvd->pvd_pid = pid;
145 (*vpp)->v_data = pvd;
146 switch (pn->pn_type) {
147 case pfstype_root:
148 (*vpp)->v_vflag = VV_ROOT;
149 #if 0
150 printf("root vnode allocated\n");
151 #endif
152 /* fall through */
153 case pfstype_dir:
154 case pfstype_this:
155 case pfstype_parent:
156 case pfstype_procdir:
157 (*vpp)->v_type = VDIR;
158 break;
159 case pfstype_file:
160 (*vpp)->v_type = VREG;
161 break;
162 case pfstype_symlink:
163 (*vpp)->v_type = VLNK;
164 break;
165 case pfstype_none:
166 KASSERT(0, ("pfs_vncache_alloc called for null node\n"));
167 default:
168 panic("%s has unexpected type: %d", pn->pn_name, pn->pn_type);
169 }
170 /*
171 * Propagate flag through to vnode so users know it can change
172 * if the process changes (i.e. execve)
173 */
174 if ((pn->pn_flags & PFS_PROCDEP) != 0)
175 (*vpp)->v_vflag |= VV_PROCDEP;
176 pvd->pvd_vnode = *vpp;
177 mtx_lock(&pfs_vncache_mutex);
178 pvd->pvd_prev = NULL;
179 pvd->pvd_next = pfs_vncache;
180 if (pvd->pvd_next)
181 pvd->pvd_next->pvd_prev = pvd;
182 pfs_vncache = pvd;
183 mtx_unlock(&pfs_vncache_mutex);
184 (*vpp)->v_vnlock->lk_flags |= LK_CANRECURSE;
185 vn_lock(*vpp, LK_RETRY | LK_EXCLUSIVE, curthread);
186 return (0);
187 }
188
189 /*
190 * Free a vnode
191 */
192 int
193 pfs_vncache_free(struct vnode *vp)
194 {
195 struct pfs_vdata *pvd;
196
197 cache_purge(vp);
198
199 mtx_lock(&pfs_vncache_mutex);
200 pvd = (struct pfs_vdata *)vp->v_data;
201 KASSERT(pvd != NULL, ("pfs_vncache_free(): no vnode data\n"));
202 if (pvd->pvd_next)
203 pvd->pvd_next->pvd_prev = pvd->pvd_prev;
204 if (pvd->pvd_prev)
205 pvd->pvd_prev->pvd_next = pvd->pvd_next;
206 else
207 pfs_vncache = pvd->pvd_next;
208 mtx_unlock(&pfs_vncache_mutex);
209
210 --pfs_vncache_entries;
211 FREE(pvd, M_PFSVNCACHE);
212 vp->v_data = NULL;
213 return (0);
214 }
215
216 /*
217 * Free all vnodes associated with a defunct process
218 */
219 static void
220 pfs_exit(struct proc *p)
221 {
222 struct pfs_vdata *pvd, *prev;
223
224 mtx_lock(&pfs_vncache_mutex);
225 /*
226 * The double loop is necessary because vgone() indirectly
227 * calls pfs_vncache_free() which frees pvd, so we have to
228 * backtrace one step every time we free a vnode.
229 */
230 /* XXX linear search... not very efficient */
231 for (pvd = pfs_vncache; pvd != NULL; pvd = pvd->pvd_next) {
232 while (pvd != NULL && pvd->pvd_pid == p->p_pid) {
233 prev = pvd->pvd_prev;
234 vgone(pvd->pvd_vnode);
235 pvd = prev ? prev->pvd_next : pfs_vncache;
236 }
237 if (pvd == NULL)
238 break;
239 }
240 mtx_unlock(&pfs_vncache_mutex);
241 }
242
243 /*
244 * Disable a pseudofs node, and free all vnodes associated with it
245 */
246 int
247 pfs_disable(struct pfs_node *pn)
248 {
249 struct pfs_vdata *pvd, *prev;
250
251 if (pn->pn_flags & PFS_DISABLED)
252 return (0);
253 mtx_lock(&pfs_vncache_mutex);
254 pn->pn_flags |= PFS_DISABLED;
255 /* see the comment about the double loop in pfs_exit() */
256 /* XXX linear search... not very efficient */
257 for (pvd = pfs_vncache; pvd != NULL; pvd = pvd->pvd_next) {
258 while (pvd != NULL && pvd->pvd_pn == pn) {
259 prev = pvd->pvd_prev;
260 vgone(pvd->pvd_vnode);
261 pvd = prev ? prev->pvd_next : pfs_vncache;
262 }
263 if (pvd == NULL)
264 break;
265 }
266 mtx_unlock(&pfs_vncache_mutex);
267 return (0);
268 }
269
270 /*
271 * Re-enable a disabled pseudofs node
272 */
273 int
274 pfs_enable(struct pfs_node *pn)
275 {
276 pn->pn_flags &= ~PFS_DISABLED;
277 return (0);
278 }
Cache object: a338c47add88db207b8348be7e43610a
|