freebsd-skq/sys/kern/vfs_hash.c
tegge 214bc5723c Make insmntque() externally visibile and allow it to fail (e.g. during
late stages of unmount).  On failure, the vnode is recycled.

Add insmntque1(), to allow for file system specific cleanup when
recycling vnode on failure.

Change getnewvnode() to no longer call insmntque().  Previously,
embryonic vnodes were put onto the list of vnode belonging to a file
system, which is unsafe for a file system marked MPSAFE.

Change vfs_hash_insert() to no longer lock the vnode.  The caller now
has that responsibility.

Change most file systems to lock the vnode and call insmntque() or
insmntque1() after a new vnode has been sufficiently setup.  Handle
failed insmntque*() calls by propagating errors to callers, possibly
after some file system specific cleanup.

Approved by:	re (kensmith)
Reviewed by:	kib
In collaboration with:	kib
2007-03-13 01:50:27 +00:00

156 lines
4.2 KiB
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("$FreeBSD$");
#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);
}