292 lines
8.5 KiB
C
292 lines
8.5 KiB
C
/* $NetBSD: overlay_vfsops.c,v 1.10 2001/11/15 09:48:22 lukem 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. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. 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 1.10 2001/11/15 09:48:22 lukem Exp $");
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#include <sys/param.h>
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#include <sys/systm.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 <miscfs/overlay/overlay.h>
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#include <miscfs/genfs/layer_extern.h>
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int ov_mount __P((struct mount *, const char *, void *,
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struct nameidata *, struct proc *));
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int ov_unmount __P((struct mount *, int, struct proc *));
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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(mp, path, data, ndp, p)
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struct mount *mp;
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const char *path;
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void *data;
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struct nameidata *ndp;
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struct proc *p;
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{
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int error = 0;
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struct overlay_args args;
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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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size_t size;
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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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/*
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* Get argument
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*/
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error = copyin(data, (caddr_t)&args, sizeof(struct overlay_args));
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if (error)
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return (error);
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/*
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* Update only does export updating.
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*/
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if (mp->mnt_flag & MNT_UPDATE) {
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lmp = MOUNTTOLAYERMOUNT(mp);
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if (args.ova_target == 0)
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return (vfs_export(mp, &lmp->layerm_export,
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&args.la.export));
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else
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return (EOPNOTSUPP);
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}
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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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if ((error = vget(lowerrootvp, LK_EXCLUSIVE | LK_RETRY)))
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return (error);
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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 = (struct overlay_mount *) malloc(sizeof(struct overlay_mount),
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M_UFSMNT, M_WAITOK); /* XXX */
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memset((caddr_t)nmp, 0, sizeof(struct overlay_mount));
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mp->mnt_data = (qaddr_t) 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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simple_lock_init(&nmp->ovm_hashlock);
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nmp->ovm_node_hashtbl = hashinit(NOVERLAYNODECACHE, HASH_LIST, M_CACHE,
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M_WAITOK, &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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free(nmp, M_UFSMNT); /* XXX */
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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, 0);
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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_flag |= VROOT;
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nmp->ovm_rootvp = vp;
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(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
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memset(mp->mnt_stat.f_mntonname + size, 0, MNAMELEN - size);
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(void) copyinstr(args.la.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
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&size);
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memset(mp->mnt_stat.f_mntfromname + size, 0, MNAMELEN - size);
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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 (0);
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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(mp, mntflags, p)
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struct mount *mp;
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int mntflags;
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struct proc *p;
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{
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struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp;
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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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/*
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* Clear out buffer cache. I don't think we
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* ever get anything cached at this level at the
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* moment, but who knows...
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*/
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#if 0
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mntflushbuf(mp, 0);
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if (mntinvalbuf(mp, 1))
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return (EBUSY);
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#endif
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if (overlay_rootvp->v_usecount > 1)
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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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* Release reference on underlying root vnode
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*/
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vrele(overlay_rootvp);
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/*
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* And 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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free(mp->mnt_data, M_UFSMNT); /* XXX */
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mp->mnt_data = 0;
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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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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_statfs,
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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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layerfs_sysctl,
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NULL, /* vfs_mountroot */
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layerfs_checkexp,
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ov_vnodeopv_descs,
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};
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