NetBSD/sys/miscfs/nullfs/null_vfsops.c

296 lines
8.5 KiB
C

/* $NetBSD: null_vfsops.c,v 1.32 2001/09/15 16:12:58 chs Exp $ */
/*
* Copyright (c) 1999 National Aeronautics & Space Administration
* All rights reserved.
*
* This software was written by William Studenmund of the
* Numerical Aerospace Simulation Facility, NASA Ames Research Center.
*
* 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.
* 3. Neither the name of the National Aeronautics & Space Administration
* nor the names of its contributors may be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION
* ``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 ADMINISTRATION OR CONTRIB-
* UTORS 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.
*/
/*
* Copyright (c) 1992, 1993, 1995
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software donated to Berkeley by
* Jan-Simon Pendry.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp
* from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
* @(#)null_vfsops.c 8.7 (Berkeley) 5/14/95
*/
/*
* Null Layer
* (See null_vnops.c for a description of what this does.)
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/types.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <miscfs/nullfs/null.h>
#include <miscfs/genfs/layer_extern.h>
int nullfs_mount __P((struct mount *, const char *, void *,
struct nameidata *, struct proc *));
int nullfs_unmount __P((struct mount *, int, struct proc *));
#define NNULLNODECACHE 16
/*
* Mount null layer
*/
int
nullfs_mount(mp, path, data, ndp, p)
struct mount *mp;
const char *path;
void *data;
struct nameidata *ndp;
struct proc *p;
{
int error = 0;
struct null_args args;
struct vnode *lowerrootvp, *vp;
struct null_mount *nmp;
struct layer_mount *lmp;
size_t size;
#ifdef NULLFS_DIAGNOSTIC
printf("nullfs_mount(mp = %p)\n", mp);
#endif
/*
* Get argument
*/
error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
if (error)
return (error);
/*
* Update only does export updating.
*/
if (mp->mnt_flag & MNT_UPDATE) {
lmp = MOUNTTOLAYERMOUNT(mp);
if (args.nulla_target == 0)
return (vfs_export(mp, &lmp->layerm_export,
&args.la.export));
else
return (EOPNOTSUPP);
}
/*
* Find lower node
*/
NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF,
UIO_USERSPACE, args.la.target, p);
if ((error = namei(ndp)) != 0)
return (error);
/*
* Sanity check on lower vnode
*/
lowerrootvp = ndp->ni_vp;
/*
* First cut at fixing up upper mount point
*/
nmp = (struct null_mount *) malloc(sizeof(struct null_mount),
M_UFSMNT, M_WAITOK); /* XXX */
memset((caddr_t)nmp, 0, sizeof(struct null_mount));
mp->mnt_data = (qaddr_t) nmp;
nmp->nullm_vfs = lowerrootvp->v_mount;
if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL)
mp->mnt_flag |= MNT_LOCAL;
/*
* Make sure that the mount point is sufficiently initialized
* that the node create call will work.
*/
vfs_getnewfsid(mp);
nmp->nullm_size = sizeof (struct null_node);
nmp->nullm_tag = VT_NULL;
nmp->nullm_bypass = layer_bypass;
nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */
nmp->nullm_vnodeop_p = null_vnodeop_p;
simple_lock_init(&nmp->nullm_hashlock);
nmp->nullm_node_hashtbl = hashinit(NNULLNODECACHE, HASH_LIST, M_CACHE,
M_WAITOK, &nmp->nullm_node_hash);
/*
* Fix up null node for root vnode
*/
error = layer_node_create(mp, lowerrootvp, &vp);
/*
* Make sure the fixup worked
*/
if (error) {
vput(lowerrootvp);
free(nmp, M_UFSMNT); /* XXX */
return (error);
}
/*
* Unlock the node
*/
VOP_UNLOCK(vp, 0);
/*
* Keep a held reference to the root vnode.
* It is vrele'd in nullfs_unmount.
*/
vp->v_flag |= VROOT;
nmp->nullm_rootvp = vp;
(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
memset(mp->mnt_stat.f_mntonname + size, 0, MNAMELEN - size);
(void) copyinstr(args.la.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
&size);
memset(mp->mnt_stat.f_mntfromname + size, 0, MNAMELEN - size);
#ifdef NULLFS_DIAGNOSTIC
printf("nullfs_mount: lower %s, alias at %s\n",
mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
#endif
return (0);
}
/*
* Free reference to null layer
*/
int
nullfs_unmount(mp, mntflags, p)
struct mount *mp;
int mntflags;
struct proc *p;
{
struct vnode *null_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
int error;
int flags = 0;
#ifdef NULLFS_DIAGNOSTIC
printf("nullfs_unmount(mp = %p)\n", mp);
#endif
if (mntflags & MNT_FORCE)
flags |= FORCECLOSE;
/*
* Clear out buffer cache. I don't think we
* ever get anything cached at this level at the
* moment, but who knows...
*/
#if 0
mntflushbuf(mp, 0);
if (mntinvalbuf(mp, 1))
return (EBUSY);
#endif
if (null_rootvp->v_usecount > 1)
return (EBUSY);
if ((error = vflush(mp, null_rootvp, flags)) != 0)
return (error);
#ifdef NULLFS_DIAGNOSTIC
vprint("alias root of lower", null_rootvp);
#endif
/*
* Release reference on underlying root vnode
*/
vrele(null_rootvp);
/*
* And blow it away for future re-use
*/
vgone(null_rootvp);
/*
* Finally, throw away the null_mount structure
*/
free(mp->mnt_data, M_UFSMNT); /* XXX */
mp->mnt_data = 0;
return 0;
}
extern const struct vnodeopv_desc null_vnodeop_opv_desc;
const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = {
&null_vnodeop_opv_desc,
NULL,
};
struct vfsops nullfs_vfsops = {
MOUNT_NULL,
nullfs_mount,
layerfs_start,
nullfs_unmount,
layerfs_root,
layerfs_quotactl,
layerfs_statfs,
layerfs_sync,
layerfs_vget,
layerfs_fhtovp,
layerfs_vptofh,
layerfs_init,
NULL,
layerfs_done,
layerfs_sysctl,
NULL, /* vfs_mountroot */
layerfs_checkexp,
nullfs_vnodeopv_descs,
};