285 lines
8.5 KiB
C
285 lines
8.5 KiB
C
/* $NetBSD: null_vfsops.c,v 1.84 2012/04/30 22:51:27 rmind Exp $ */
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/*
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* Copyright (c) 1999 National Aeronautics & Space Administration
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* All rights reserved.
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*
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* This software was written by William Studenmund of the
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* Numerical Aerospace Simulation Facility, NASA Ames Research Center.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the National Aeronautics & Space Administration
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* nor the names of its contributors may be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB-
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* UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 1992, 1993, 1995
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software donated to Berkeley by
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* Jan-Simon Pendry.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp
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* from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
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* @(#)null_vfsops.c 8.7 (Berkeley) 5/14/95
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*/
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/*
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* Null file-system: VFS operations.
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*
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* See null_vnops.c for a description.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: null_vfsops.c,v 1.84 2012/04/30 22:51:27 rmind Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysctl.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/namei.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <miscfs/nullfs/null.h>
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#include <miscfs/genfs/layer_extern.h>
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MODULE(MODULE_CLASS_VFS, null, "layerfs");
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VFS_PROTOS(nullfs);
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static struct sysctllog *nullfs_sysctl_log;
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int
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nullfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
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{
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struct vnode *lowerrootvp, *vp;
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struct null_args *args = data;
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struct null_mount *nmp;
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struct layer_mount *lmp;
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struct pathbuf *pb;
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struct nameidata nd;
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int error;
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if (*data_len < sizeof(*args))
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return EINVAL;
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if (mp->mnt_flag & MNT_GETARGS) {
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lmp = MOUNTTOLAYERMOUNT(mp);
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if (lmp == NULL)
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return EIO;
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args->la.target = NULL;
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*data_len = sizeof(*args);
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return 0;
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}
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/* Update is not supported. */
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if (mp->mnt_flag & MNT_UPDATE)
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return EOPNOTSUPP;
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/* Find the lower vnode and lock it. */
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error = pathbuf_copyin(args->la.target, &pb);
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if (error) {
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return error;
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}
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NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, pb);
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if ((error = namei(&nd)) != 0) {
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pathbuf_destroy(pb);
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return error;
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}
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lowerrootvp = nd.ni_vp;
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pathbuf_destroy(pb);
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/* Create the mount point. */
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nmp = kmem_zalloc(sizeof(struct null_mount), KM_SLEEP);
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mp->mnt_data = nmp;
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nmp->nullm_vfs = lowerrootvp->v_mount;
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if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL)
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mp->mnt_flag |= MNT_LOCAL;
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/*
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* Make sure that the mount point is sufficiently initialized
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* that the node create call will work.
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*/
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vfs_getnewfsid(mp);
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nmp->nullm_size = sizeof(struct null_node);
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nmp->nullm_tag = VT_NULL;
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nmp->nullm_bypass = layer_bypass;
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nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */
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nmp->nullm_vnodeop_p = null_vnodeop_p;
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mutex_init(&nmp->nullm_hashlock, MUTEX_DEFAULT, IPL_NONE);
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nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, true,
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&nmp->nullm_node_hash);
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/* Setup a null node for root vnode. */
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error = layer_node_create(mp, lowerrootvp, &vp);
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if (error) {
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vput(lowerrootvp);
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hashdone(nmp->nullm_node_hashtbl, HASH_LIST,
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nmp->nullm_node_hash);
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kmem_free(nmp, sizeof(struct null_mount));
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return error;
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}
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/*
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* Keep a held reference to the root vnode. It will be released on
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* umount. Note: nullfs is MP-safe.
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*/
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vp->v_vflag |= VV_ROOT;
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nmp->nullm_rootvp = vp;
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mp->mnt_iflag |= IMNT_MPSAFE;
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VOP_UNLOCK(vp);
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error = set_statvfs_info(path, UIO_USERSPACE, args->la.target,
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UIO_USERSPACE, mp->mnt_op->vfs_name, mp, curlwp);
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return error;
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}
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int
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nullfs_unmount(struct mount *mp, int mntflags)
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{
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struct null_mount *nmp = MOUNTTONULLMOUNT(mp);
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struct vnode *null_rootvp = nmp->nullm_rootvp;
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int error, flags = 0;
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if (mntflags & MNT_FORCE)
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flags |= FORCECLOSE;
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if (null_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0)
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return EBUSY;
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if ((error = vflush(mp, null_rootvp, flags)) != 0)
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return error;
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/* Eliminate all activity and release the vnode. */
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vgone(null_rootvp);
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/* Finally, destroy the mount point structures. */
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hashdone(nmp->nullm_node_hashtbl, HASH_LIST, nmp->nullm_node_hash);
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mutex_destroy(&nmp->nullm_hashlock);
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kmem_free(mp->mnt_data, sizeof(struct null_mount));
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mp->mnt_data = NULL;
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return 0;
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}
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extern const struct vnodeopv_desc null_vnodeop_opv_desc;
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const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = {
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&null_vnodeop_opv_desc,
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NULL,
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};
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struct vfsops nullfs_vfsops = {
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MOUNT_NULL,
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sizeof (struct null_args),
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nullfs_mount,
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layerfs_start,
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nullfs_unmount,
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layerfs_root,
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layerfs_quotactl,
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layerfs_statvfs,
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layerfs_sync,
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layerfs_vget,
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layerfs_fhtovp,
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layerfs_vptofh,
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layerfs_init,
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NULL,
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layerfs_done,
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NULL, /* vfs_mountroot */
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layerfs_snapshot,
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vfs_stdextattrctl,
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(void *)eopnotsupp, /* vfs_suspendctl */
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layerfs_renamelock_enter,
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layerfs_renamelock_exit,
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(void *)eopnotsupp,
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nullfs_vnodeopv_descs,
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0,
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{ NULL, NULL },
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};
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static int
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null_modcmd(modcmd_t cmd, void *arg)
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{
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int error;
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switch (cmd) {
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case MODULE_CMD_INIT:
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error = vfs_attach(&nullfs_vfsops);
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if (error != 0)
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break;
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sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL,
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CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "vfs", NULL,
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NULL, 0, NULL, 0,
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CTL_VFS, CTL_EOL);
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sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL,
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CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "null",
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SYSCTL_DESCR("Loopback file system"),
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NULL, 0, NULL, 0,
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CTL_VFS, 9, CTL_EOL);
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/*
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* XXX the "9" above could be dynamic, thereby eliminating
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* one more instance of the "number to vfs" mapping problem,
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* but "9" is the order as taken from sys/mount.h
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*/
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break;
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case MODULE_CMD_FINI:
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error = vfs_detach(&nullfs_vfsops);
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if (error != 0)
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break;
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sysctl_teardown(&nullfs_sysctl_log);
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break;
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default:
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error = ENOTTY;
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break;
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}
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return error;
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}
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