diff options
Diffstat (limited to 'freebsd/sys/kern/vfs_hash.c')
| -rw-r--r-- | freebsd/sys/kern/vfs_hash.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/freebsd/sys/kern/vfs_hash.c b/freebsd/sys/kern/vfs_hash.c new file mode 100644 index 00000000..b938f485 --- /dev/null +++ b/freebsd/sys/kern/vfs_hash.c @@ -0,0 +1,234 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause-FreeBSD + * + * 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("$FreeBSD$"); + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/kernel.h> +#include <sys/malloc.h> +#include <sys/mount.h> +#include <sys/rwlock.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 rwlock vfs_hash_lock; + +static void +vfs_hashinit(void *dummy __unused) +{ + + vfs_hash_tbl = hashinit(desiredvnodes, M_VFS_HASH, &vfs_hash_mask); + rw_init(&vfs_hash_lock, "vfs hash"); + 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); + +u_int +vfs_hash_index(struct vnode *vp) +{ + + return (vp->v_hash + vp->v_mount->mnt_hashseed); +} + +static struct vfs_hash_head * +vfs_hash_bucket(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) { + rw_rlock(&vfs_hash_lock); + LIST_FOREACH(vp, vfs_hash_bucket(mp, hash), v_hashlist) { + if (vp->v_hash != hash) + continue; + if (vp->v_mount != mp) + continue; + if (fn != NULL && fn(vp, arg)) + continue; + vhold(vp); + rw_runlock(&vfs_hash_lock); + error = vget(vp, flags | LK_VNHELD, td); + if (error == ENOENT && (flags & LK_NOWAIT) == 0) + break; + if (error) + return (error); + *vpp = vp; + return (0); + } + if (vp == NULL) { + rw_runlock(&vfs_hash_lock); + *vpp = NULL; + return (0); + } + } +} + +void +vfs_hash_ref(const struct mount *mp, u_int hash, struct thread *td, + struct vnode **vpp, vfs_hash_cmp_t *fn, void *arg) +{ + struct vnode *vp; + + while (1) { + rw_rlock(&vfs_hash_lock); + LIST_FOREACH(vp, vfs_hash_bucket(mp, hash), v_hashlist) { + if (vp->v_hash != hash) + continue; + if (vp->v_mount != mp) + continue; + if (fn != NULL && fn(vp, arg)) + continue; + vhold(vp); + rw_runlock(&vfs_hash_lock); + vref(vp); + vdrop(vp); + *vpp = vp; + return; + } + if (vp == NULL) { + rw_runlock(&vfs_hash_lock); + *vpp = NULL; + return; + } + } +} + +void +vfs_hash_remove(struct vnode *vp) +{ + + rw_wlock(&vfs_hash_lock); + LIST_REMOVE(vp, v_hashlist); + rw_wunlock(&vfs_hash_lock); +} + +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) { + rw_wlock(&vfs_hash_lock); + LIST_FOREACH(vp2, + vfs_hash_bucket(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; + vhold(vp2); + rw_wunlock(&vfs_hash_lock); + error = vget(vp2, flags | LK_VNHELD, td); + if (error == ENOENT && (flags & LK_NOWAIT) == 0) + break; + rw_wlock(&vfs_hash_lock); + LIST_INSERT_HEAD(&vfs_hash_side, vp, v_hashlist); + rw_wunlock(&vfs_hash_lock); + vput(vp); + if (!error) + *vpp = vp2; + return (error); + } + if (vp2 == NULL) + break; + + } + vp->v_hash = hash; + LIST_INSERT_HEAD(vfs_hash_bucket(vp->v_mount, hash), vp, v_hashlist); + rw_wunlock(&vfs_hash_lock); + return (0); +} + +void +vfs_hash_rehash(struct vnode *vp, u_int hash) +{ + + rw_wlock(&vfs_hash_lock); + LIST_REMOVE(vp, v_hashlist); + LIST_INSERT_HEAD(vfs_hash_bucket(vp->v_mount, hash), vp, v_hashlist); + vp->v_hash = hash; + rw_wunlock(&vfs_hash_lock); +} + +void +vfs_hash_changesize(int newmaxvnodes) +{ + struct vfs_hash_head *vfs_hash_newtbl, *vfs_hash_oldtbl; + u_long vfs_hash_newmask, vfs_hash_oldmask; + struct vnode *vp; + int i; + + vfs_hash_newtbl = hashinit(newmaxvnodes, M_VFS_HASH, + &vfs_hash_newmask); + /* If same hash table size, nothing to do */ + if (vfs_hash_mask == vfs_hash_newmask) { + free(vfs_hash_newtbl, M_VFS_HASH); + return; + } + /* + * Move everything from the old hash table to the new table. + * None of the vnodes in the table can be recycled because to + * do so, they have to be removed from the hash table. + */ + rw_wlock(&vfs_hash_lock); + vfs_hash_oldtbl = vfs_hash_tbl; + vfs_hash_oldmask = vfs_hash_mask; + vfs_hash_tbl = vfs_hash_newtbl; + vfs_hash_mask = vfs_hash_newmask; + for (i = 0; i <= vfs_hash_oldmask; i++) { + while ((vp = LIST_FIRST(&vfs_hash_oldtbl[i])) != NULL) { + LIST_REMOVE(vp, v_hashlist); + LIST_INSERT_HEAD( + vfs_hash_bucket(vp->v_mount, vp->v_hash), + vp, v_hashlist); + } + } + rw_wunlock(&vfs_hash_lock); + free(vfs_hash_oldtbl, M_VFS_HASH); +} |