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/* $NetBSD: null_vfsops.c,v 1.101 2023/02/06 10:32:58 hannken 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. 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 file-system: VFS operations.
*
* See null_vnops.c for a description.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: null_vfsops.c,v 1.101 2023/02/06 10:32:58 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/module.h>
#include <miscfs/nullfs/null.h>
#include <miscfs/genfs/layer_extern.h>
MODULE(MODULE_CLASS_VFS, null, "layerfs");
VFS_PROTOS(nullfs);
int
nullfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
{
struct vnode *lowerrootvp, *vp;
struct null_args *args = data;
struct null_mount *nmp;
struct layer_mount *lmp;
struct pathbuf *pb;
struct nameidata nd;
int error;
if (args == NULL)
return EINVAL;
if (*data_len < sizeof(*args))
return EINVAL;
if (mp->mnt_flag & MNT_GETARGS) {
lmp = MOUNTTOLAYERMOUNT(mp);
if (lmp == NULL)
return EIO;
args->la.target = NULL;
*data_len = sizeof(*args);
return 0;
}
/* Update is not supported. */
if (mp->mnt_flag & MNT_UPDATE)
return EOPNOTSUPP;
/* Find the lower vnode and lock it. */
error = pathbuf_copyin(args->la.target, &pb);
if (error) {
return error;
}
NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, pb);
if ((error = namei(&nd)) != 0) {
pathbuf_destroy(pb);
return error;
}
lowerrootvp = nd.ni_vp;
pathbuf_destroy(pb);
/* Create the mount point. */
nmp = kmem_zalloc(sizeof(struct null_mount), KM_SLEEP);
mp->mnt_data = nmp;
mp->mnt_iflag |= lowerrootvp->v_mount->mnt_iflag & IMNT_MPSAFE;
mp->mnt_iflag |= lowerrootvp->v_mount->mnt_iflag & IMNT_SHRLOOKUP;
/*
* Make sure that the mount point is sufficiently initialized
* that the node create call will work.
*/
vfs_getnewfsid(mp);
error = vfs_set_lowermount(mp, lowerrootvp->v_mount);
if (error) {
vput(lowerrootvp);
kmem_free(nmp, sizeof(struct null_mount));
return error;
}
nmp->nullm_size = sizeof(struct null_node);
nmp->nullm_tag = VT_NULL;
nmp->nullm_bypass = layer_bypass;
nmp->nullm_vnodeop_p = null_vnodeop_p;
/* Setup a null node for root vnode. */
VOP_UNLOCK(lowerrootvp);
error = layer_node_create(mp, lowerrootvp, &vp);
if (error) {
vrele(lowerrootvp);
kmem_free(nmp, sizeof(struct null_mount));
return error;
}
/*
* Keep a held reference to the root vnode. It will be released on
* umount. Note: nullfs is MP-safe.
*/
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
vp->v_vflag |= VV_ROOT;
nmp->nullm_rootvp = vp;
VOP_UNLOCK(vp);
error = set_statvfs_info(path, UIO_USERSPACE, args->la.target,
UIO_USERSPACE, mp->mnt_op->vfs_name, mp, curlwp);
if (error)
return error;
if (mp->mnt_lower->mnt_flag & MNT_LOCAL)
mp->mnt_flag |= MNT_LOCAL;
return 0;
}
int
nullfs_unmount(struct mount *mp, int mntflags)
{
struct null_mount *nmp = MOUNTTONULLMOUNT(mp);
struct vnode *null_rootvp = nmp->nullm_rootvp;
int error, flags = 0;
if (mntflags & MNT_FORCE)
flags |= FORCECLOSE;
if (vrefcnt(null_rootvp) > 1 && (mntflags & MNT_FORCE) == 0)
return EBUSY;
if ((error = vflush(mp, null_rootvp, flags)) != 0)
return error;
/* Eliminate all activity and release the vnode. */
vgone(null_rootvp);
/* Finally, destroy the mount point structures. */
kmem_free(mp->mnt_data, sizeof(struct null_mount));
mp->mnt_data = NULL;
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 = {
.vfs_name = MOUNT_NULL,
.vfs_min_mount_data = sizeof (struct null_args),
.vfs_mount = nullfs_mount,
.vfs_start = layerfs_start,
.vfs_unmount = nullfs_unmount,
.vfs_root = layerfs_root,
.vfs_quotactl = layerfs_quotactl,
.vfs_statvfs = layerfs_statvfs,
.vfs_sync = layerfs_sync,
.vfs_loadvnode = layerfs_loadvnode,
.vfs_vget = layerfs_vget,
.vfs_fhtovp = layerfs_fhtovp,
.vfs_vptofh = layerfs_vptofh,
.vfs_init = layerfs_init,
.vfs_done = layerfs_done,
.vfs_snapshot = layerfs_snapshot,
.vfs_extattrctl = vfs_stdextattrctl,
.vfs_suspendctl = layerfs_suspendctl,
.vfs_renamelock_enter = layerfs_renamelock_enter,
.vfs_renamelock_exit = layerfs_renamelock_exit,
.vfs_fsync = (void *)eopnotsupp,
.vfs_opv_descs = nullfs_vnodeopv_descs
};
SYSCTL_SETUP(nullfs_sysctl_setup, "nullfs sysctl")
{
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "null",
SYSCTL_DESCR("Loopback file system"),
NULL, 0, NULL, 0,
CTL_VFS, 9, CTL_EOL);
/*
* XXX the "9" above could be dynamic, thereby eliminating
* one more instance of the "number to vfs" mapping problem,
* but "9" is the order as taken from sys/mount.h
*/
}
static int
null_modcmd(modcmd_t cmd, void *arg)
{
int error;
switch (cmd) {
case MODULE_CMD_INIT:
error = vfs_attach(&nullfs_vfsops);
if (error != 0)
break;
break;
case MODULE_CMD_FINI:
error = vfs_detach(&nullfs_vfsops);
if (error != 0)
break;
break;
default:
error = ENOTTY;
break;
}
return error;
}
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