2 * Copyright (c) 2005 Poul-Henning Kamp
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/kernel.h>
34 #include <sys/malloc.h>
35 #include <sys/mount.h>
36 #include <sys/vnode.h>
38 static MALLOC_DEFINE(M_VFS_HASH, "vfs_hash", "VFS hash table");
40 static LIST_HEAD(vfs_hash_head, vnode) *vfs_hash_tbl;
41 static LIST_HEAD(,vnode) vfs_hash_side;
42 static u_long vfs_hash_mask;
43 static struct mtx vfs_hash_mtx;
46 vfs_hashinit(void *dummy __unused)
49 vfs_hash_tbl = hashinit(desiredvnodes, M_VFS_HASH, &vfs_hash_mask);
50 mtx_init(&vfs_hash_mtx, "vfs hash", NULL, MTX_DEF);
51 LIST_INIT(&vfs_hash_side);
54 /* Must be SI_ORDER_SECOND so desiredvnodes is available */
55 SYSINIT(vfs_hash, SI_SUB_VFS, SI_ORDER_SECOND, vfs_hashinit, NULL);
58 vfs_hash_index(struct vnode *vp)
61 return (vp->v_hash + vp->v_mount->mnt_hashseed);
64 static struct vfs_hash_head *
65 vfs_hash_bucket(const struct mount *mp, u_int hash)
68 return (&vfs_hash_tbl[(hash + mp->mnt_hashseed) & vfs_hash_mask]);
72 vfs_hash_get(const struct mount *mp, u_int hash, int flags, struct thread *td,
73 struct vnode **vpp, vfs_hash_cmp_t *fn, void *arg)
79 mtx_lock(&vfs_hash_mtx);
80 LIST_FOREACH(vp, vfs_hash_bucket(mp, hash), v_hashlist) {
81 if (vp->v_hash != hash)
83 if (vp->v_mount != mp)
85 if (fn != NULL && fn(vp, arg))
88 mtx_unlock(&vfs_hash_mtx);
89 error = vget(vp, flags | LK_INTERLOCK, td);
90 if (error == ENOENT && (flags & LK_NOWAIT) == 0)
98 mtx_unlock(&vfs_hash_mtx);
106 vfs_hash_remove(struct vnode *vp)
109 mtx_lock(&vfs_hash_mtx);
110 LIST_REMOVE(vp, v_hashlist);
111 mtx_unlock(&vfs_hash_mtx);
115 vfs_hash_insert(struct vnode *vp, u_int hash, int flags, struct thread *td,
116 struct vnode **vpp, vfs_hash_cmp_t *fn, void *arg)
123 mtx_lock(&vfs_hash_mtx);
125 vfs_hash_bucket(vp->v_mount, hash), v_hashlist) {
126 if (vp2->v_hash != hash)
128 if (vp2->v_mount != vp->v_mount)
130 if (fn != NULL && fn(vp2, arg))
133 mtx_unlock(&vfs_hash_mtx);
134 error = vget(vp2, flags | LK_INTERLOCK, td);
135 if (error == ENOENT && (flags & LK_NOWAIT) == 0)
137 mtx_lock(&vfs_hash_mtx);
138 LIST_INSERT_HEAD(&vfs_hash_side, vp, v_hashlist);
139 mtx_unlock(&vfs_hash_mtx);
150 LIST_INSERT_HEAD(vfs_hash_bucket(vp->v_mount, hash), vp, v_hashlist);
151 mtx_unlock(&vfs_hash_mtx);
156 vfs_hash_rehash(struct vnode *vp, u_int hash)
159 mtx_lock(&vfs_hash_mtx);
160 LIST_REMOVE(vp, v_hashlist);
161 LIST_INSERT_HEAD(vfs_hash_bucket(vp->v_mount, hash), vp, v_hashlist);
163 mtx_unlock(&vfs_hash_mtx);
167 vfs_hash_changesize(int newmaxvnodes)
169 struct vfs_hash_head *vfs_hash_newtbl, *vfs_hash_oldtbl;
170 u_long vfs_hash_newmask, vfs_hash_oldmask;
174 vfs_hash_newtbl = hashinit(newmaxvnodes, M_VFS_HASH,
176 /* If same hash table size, nothing to do */
177 if (vfs_hash_mask == vfs_hash_newmask) {
178 free(vfs_hash_newtbl, M_VFS_HASH);
182 * Move everything from the old hash table to the new table.
183 * None of the vnodes in the table can be recycled because to
184 * do so, they have to be removed from the hash table.
186 mtx_lock(&vfs_hash_mtx);
187 vfs_hash_oldtbl = vfs_hash_tbl;
188 vfs_hash_oldmask = vfs_hash_mask;
189 vfs_hash_tbl = vfs_hash_newtbl;
190 vfs_hash_mask = vfs_hash_newmask;
191 for (i = 0; i <= vfs_hash_oldmask; i++) {
192 while ((vp = LIST_FIRST(&vfs_hash_oldtbl[i])) != NULL) {
193 LIST_REMOVE(vp, v_hashlist);
195 vfs_hash_bucket(vp->v_mount, vp->v_hash),
199 mtx_unlock(&vfs_hash_mtx);
200 free(vfs_hash_oldtbl, M_VFS_HASH);