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, struct vnode **vpp, vfs_hash_cmp_t *fn, void *arg)
78 mtx_lock(&vfs_hash_mtx);
79 LIST_FOREACH(vp, vfs_hash_bucket(mp, hash), v_hashlist) {
80 if (vp->v_hash != hash)
82 if (vp->v_mount != mp)
84 if (fn != NULL && fn(vp, arg))
87 mtx_unlock(&vfs_hash_mtx);
88 error = vget(vp, flags | LK_INTERLOCK, td);
89 if (error == ENOENT && (flags & LK_NOWAIT) == 0)
97 mtx_unlock(&vfs_hash_mtx);
105 vfs_hash_remove(struct vnode *vp)
108 mtx_lock(&vfs_hash_mtx);
109 LIST_REMOVE(vp, v_hashlist);
110 mtx_unlock(&vfs_hash_mtx);
114 vfs_hash_insert(struct vnode *vp, u_int hash, int flags, struct thread *td, struct vnode **vpp, vfs_hash_cmp_t *fn, void *arg)
121 mtx_lock(&vfs_hash_mtx);
123 vfs_hash_bucket(vp->v_mount, hash), v_hashlist) {
124 if (vp2->v_hash != hash)
126 if (vp2->v_mount != vp->v_mount)
128 if (fn != NULL && fn(vp2, arg))
131 mtx_unlock(&vfs_hash_mtx);
132 error = vget(vp2, flags | LK_INTERLOCK, td);
133 if (error == ENOENT && (flags & LK_NOWAIT) == 0)
135 mtx_lock(&vfs_hash_mtx);
136 LIST_INSERT_HEAD(&vfs_hash_side, vp, v_hashlist);
137 mtx_unlock(&vfs_hash_mtx);
148 LIST_INSERT_HEAD(vfs_hash_bucket(vp->v_mount, hash), vp, v_hashlist);
149 mtx_unlock(&vfs_hash_mtx);
154 vfs_hash_rehash(struct vnode *vp, u_int hash)
157 mtx_lock(&vfs_hash_mtx);
158 LIST_REMOVE(vp, v_hashlist);
159 LIST_INSERT_HEAD(vfs_hash_bucket(vp->v_mount, hash), vp, v_hashlist);
161 mtx_unlock(&vfs_hash_mtx);
165 vfs_hash_changesize(int newmaxvnodes)
167 struct vfs_hash_head *vfs_hash_newtbl, *vfs_hash_oldtbl;
168 u_long vfs_hash_newmask, vfs_hash_oldmask;
172 vfs_hash_newtbl = hashinit(newmaxvnodes, M_VFS_HASH,
174 /* If same hash table size, nothing to do */
175 if (vfs_hash_mask == vfs_hash_newmask) {
176 free(vfs_hash_newtbl, M_VFS_HASH);
180 * Move everything from the old hash table to the new table.
181 * None of the vnodes in the table can be recycled because to
182 * do so, they have to be removed from the hash table.
184 mtx_lock(&vfs_hash_mtx);
185 vfs_hash_oldtbl = vfs_hash_tbl;
186 vfs_hash_oldmask = vfs_hash_mask;
187 vfs_hash_tbl = vfs_hash_newtbl;
188 vfs_hash_mask = vfs_hash_newmask;
189 for (i = 0; i <= vfs_hash_oldmask; i++) {
190 while ((vp = LIST_FIRST(&vfs_hash_oldtbl[i])) != NULL) {
191 LIST_REMOVE(vp, v_hashlist);
193 vfs_hash_bucket(vp->v_mount, vp->v_hash),
197 mtx_unlock(&vfs_hash_mtx);
198 free(vfs_hash_oldtbl, M_VFS_HASH);