Current Path : /sys/kern/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
Current File : //sys/kern/vfs_hash.c |
/*- * Copyright (c) 2005 Poul-Henning Kamp * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * */ #include <sys/cdefs.h> __FBSDID("$FreeBSD: release/9.1.0/sys/kern/vfs_hash.c 177253 2008-03-16 10:58:09Z rwatson $"); #include <sys/param.h> #include <sys/systm.h> #include <sys/kernel.h> #include <sys/malloc.h> #include <sys/mount.h> #include <sys/vnode.h> static MALLOC_DEFINE(M_VFS_HASH, "vfs_hash", "VFS hash table"); static LIST_HEAD(vfs_hash_head, vnode) *vfs_hash_tbl; static LIST_HEAD(,vnode) vfs_hash_side; static u_long vfs_hash_mask; static struct mtx vfs_hash_mtx; static void vfs_hashinit(void *dummy __unused) { vfs_hash_tbl = hashinit(desiredvnodes, M_VFS_HASH, &vfs_hash_mask); mtx_init(&vfs_hash_mtx, "vfs hash", NULL, MTX_DEF); LIST_INIT(&vfs_hash_side); } /* Must be SI_ORDER_SECOND so desiredvnodes is available */ SYSINIT(vfs_hash, SI_SUB_VFS, SI_ORDER_SECOND, vfs_hashinit, NULL); static struct vfs_hash_head * vfs_hash_index(const struct mount *mp, u_int hash) { return(&vfs_hash_tbl[(hash + mp->mnt_hashseed) & vfs_hash_mask]); } int 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) { struct vnode *vp; int error; while (1) { mtx_lock(&vfs_hash_mtx); LIST_FOREACH(vp, vfs_hash_index(mp, hash), v_hashlist) { if (vp->v_hash != hash) continue; if (vp->v_mount != mp) continue; if (fn != NULL && fn(vp, arg)) continue; VI_LOCK(vp); mtx_unlock(&vfs_hash_mtx); error = vget(vp, flags | LK_INTERLOCK, td); if (error == ENOENT && (flags & LK_NOWAIT) == 0) break; if (error) return (error); *vpp = vp; return (0); } if (vp == NULL) { mtx_unlock(&vfs_hash_mtx); *vpp = NULL; return (0); } } } void vfs_hash_remove(struct vnode *vp) { mtx_lock(&vfs_hash_mtx); LIST_REMOVE(vp, v_hashlist); mtx_unlock(&vfs_hash_mtx); } int vfs_hash_insert(struct vnode *vp, u_int hash, int flags, struct thread *td, struct vnode **vpp, vfs_hash_cmp_t *fn, void *arg) { struct vnode *vp2; int error; *vpp = NULL; while (1) { mtx_lock(&vfs_hash_mtx); LIST_FOREACH(vp2, vfs_hash_index(vp->v_mount, hash), v_hashlist) { if (vp2->v_hash != hash) continue; if (vp2->v_mount != vp->v_mount) continue; if (fn != NULL && fn(vp2, arg)) continue; VI_LOCK(vp2); mtx_unlock(&vfs_hash_mtx); error = vget(vp2, flags | LK_INTERLOCK, td); if (error == ENOENT && (flags & LK_NOWAIT) == 0) break; mtx_lock(&vfs_hash_mtx); LIST_INSERT_HEAD(&vfs_hash_side, vp, v_hashlist); mtx_unlock(&vfs_hash_mtx); vput(vp); if (!error) *vpp = vp2; return (error); } if (vp2 == NULL) break; } vp->v_hash = hash; LIST_INSERT_HEAD(vfs_hash_index(vp->v_mount, hash), vp, v_hashlist); mtx_unlock(&vfs_hash_mtx); return (0); } void vfs_hash_rehash(struct vnode *vp, u_int hash) { mtx_lock(&vfs_hash_mtx); LIST_REMOVE(vp, v_hashlist); LIST_INSERT_HEAD(vfs_hash_index(vp->v_mount, hash), vp, v_hashlist); vp->v_hash = hash; mtx_unlock(&vfs_hash_mtx); }