313 lines
8.9 KiB
C
313 lines
8.9 KiB
C
/* $NetBSD: overlay_vfsops.c,v 1.57 2012/04/30 22:51:27 rmind Exp $ */
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/*
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* Copyright (c) 1999, 2000 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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* Overlay Layer
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* (See overlay_vnops.c for a description of what this does.)
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: overlay_vfsops.c,v 1.57 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/time.h>
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#include <sys/proc.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/overlay/overlay.h>
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#include <miscfs/genfs/layer_extern.h>
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MODULE(MODULE_CLASS_VFS, overlay, "layerfs");
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VFS_PROTOS(ov);
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static struct sysctllog *overlay_sysctl_log;
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#define NOVERLAYNODECACHE 16
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/*
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* Mount overlay layer
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*/
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int
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ov_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
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{
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struct lwp *l = curlwp;
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int error = 0;
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struct overlay_args *args = data;
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struct vnode *lowerrootvp, *vp;
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struct overlay_mount *nmp;
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struct layer_mount *lmp;
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#ifdef OVERLAYFS_DIAGNOSTIC
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printf("ov_mount(mp = %p)\n", mp);
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#endif
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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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/*
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* Update is not supported
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*/
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if (mp->mnt_flag & MNT_UPDATE)
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return EOPNOTSUPP;
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/*
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* Find lower node
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*/
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lowerrootvp = mp->mnt_vnodecovered;
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vref(lowerrootvp);
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if ((error = vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY))) {
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vrele(lowerrootvp);
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return (error);
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}
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/*
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* First cut at fixing up upper mount point
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*/
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nmp = kmem_zalloc(sizeof(struct overlay_mount), KM_SLEEP);
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mp->mnt_data = nmp;
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nmp->ovm_vfs = lowerrootvp->v_mount;
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if (nmp->ovm_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->ovm_size = sizeof (struct overlay_node);
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nmp->ovm_tag = VT_OVERLAY;
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nmp->ovm_bypass = layer_bypass;
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nmp->ovm_alloc = layer_node_alloc; /* the default alloc is fine */
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nmp->ovm_vnodeop_p = overlay_vnodeop_p;
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mutex_init(&nmp->ovm_hashlock, MUTEX_DEFAULT, IPL_NONE);
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nmp->ovm_node_hashtbl = hashinit(NOVERLAYNODECACHE, HASH_LIST, true,
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&nmp->ovm_node_hash);
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/*
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* Fix up overlay node for root vnode
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*/
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error = layer_node_create(mp, lowerrootvp, &vp);
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/*
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* Make sure the fixup worked
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*/
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if (error) {
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vput(lowerrootvp);
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hashdone(nmp->ovm_node_hashtbl, HASH_LIST, nmp->ovm_node_hash);
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kmem_free(nmp, sizeof(struct overlay_mount));
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return error;
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}
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/*
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* Unlock the node
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*/
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VOP_UNLOCK(vp);
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/*
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* Keep a held reference to the root vnode.
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* It is vrele'd in ov_unmount.
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*/
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vp->v_vflag |= VV_ROOT;
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nmp->ovm_rootvp = 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, l);
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#ifdef OVERLAYFS_DIAGNOSTIC
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printf("ov_mount: lower %s, alias at %s\n",
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mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
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#endif
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return error;
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}
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/*
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* Free reference to overlay layer
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*/
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int
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ov_unmount(struct mount *mp, int mntflags)
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{
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struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp;
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struct overlay_mount *omp;
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int error;
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int flags = 0;
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#ifdef OVERLAYFS_DIAGNOSTIC
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printf("ov_unmount(mp = %p)\n", mp);
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#endif
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if (mntflags & MNT_FORCE)
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flags |= FORCECLOSE;
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if (overlay_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0)
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return (EBUSY);
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if ((error = vflush(mp, overlay_rootvp, flags)) != 0)
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return (error);
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#ifdef OVERLAYFS_DIAGNOSTIC
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vprint("alias root of lower", overlay_rootvp);
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#endif
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/*
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* Blow it away for future re-use
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*/
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vgone(overlay_rootvp);
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/*
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* Finally, throw away the overlay_mount structure
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*/
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omp = mp->mnt_data;
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mutex_destroy(&omp->ovm_hashlock);
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hashdone(omp->ovm_node_hashtbl, HASH_LIST, omp->ovm_node_hash);
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kmem_free(omp, sizeof(struct overlay_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 overlay_vnodeop_opv_desc;
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const struct vnodeopv_desc * const ov_vnodeopv_descs[] = {
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&overlay_vnodeop_opv_desc,
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NULL,
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};
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struct vfsops overlay_vfsops = {
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MOUNT_OVERLAY,
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sizeof (struct overlay_args),
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ov_mount,
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layerfs_start,
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ov_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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ov_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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overlay_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(&overlay_vfsops);
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if (error != 0)
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break;
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sysctl_createv(&overlay_sysctl_log, 0, NULL, NULL,
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CTLFLAG_PERMANENT, 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(&overlay_sysctl_log, 0, NULL, NULL,
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CTLFLAG_PERMANENT, CTLTYPE_NODE, "overlay",
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SYSCTL_DESCR("Overlay file system"),
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NULL, 0, NULL, 0,
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CTL_VFS, CTL_CREATE, CTL_EOL);
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break;
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case MODULE_CMD_FINI:
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error = vfs_detach(&overlay_vfsops);
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if (error != 0)
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break;
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sysctl_teardown(&overlay_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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