0864ef1e8a
the number of references on the filesystem root vnode to be both expected and released. Many filesystems hold an extra reference on the filesystem root vnode, which must be accounted for when determining if the filesystem is busy and then released if it isn't busy. The old `skipvp' approach required individual filesystem xxx_unmount functions to re-implement much of vflush()'s logic to deal with the root vnode. All 9 filesystems that hold an extra reference on the root vnode got the logic wrong in the case of forced unmounts, so `umount -f' would always fail if there were any extra root vnode references. Fix this issue centrally in vflush(), now that we can. This commit also fixes a vnode reference leak in devfs, which could result in idle devfs filesystems that refuse to unmount. Reviewed by: phk, bp
202 lines
5.0 KiB
C
202 lines
5.0 KiB
C
/*
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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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* Copyright (c) 2000
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* Poul-Henning Kamp. 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. 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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* @(#)kernfs_vfsops.c 8.10 (Berkeley) 5/14/95
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* From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
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*
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* $FreeBSD$
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*/
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#include "opt_devfs.h"
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#ifndef NODEVFS
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mount.h>
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#include <sys/proc.h>
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#include <sys/socket.h>
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#include <sys/vnode.h>
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#include <fs/devfs/devfs.h>
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MALLOC_DEFINE(M_DEVFS, "DEVFS", "DEVFS data");
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static int devfs_mount __P((struct mount *mp, char *path, caddr_t data,
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struct nameidata *ndp, struct proc *p));
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static int devfs_unmount __P((struct mount *mp, int mntflags,
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struct proc *p));
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static int devfs_root __P((struct mount *mp, struct vnode **vpp));
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static int devfs_statfs __P((struct mount *mp, struct statfs *sbp,
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struct proc *p));
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/*
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* Mount the filesystem
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*/
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static int
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devfs_mount(mp, path, data, ndp, p)
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struct mount *mp;
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char *path;
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caddr_t 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;
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struct devfs_mount *fmp;
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struct vnode *rvp;
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error = 0;
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/*
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* XXX: flag changes.
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*/
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if (mp->mnt_flag & MNT_UPDATE)
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return (EOPNOTSUPP);
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MALLOC(fmp, struct devfs_mount *, sizeof(struct devfs_mount),
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M_DEVFS, M_WAITOK | M_ZERO);
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lockinit(&fmp->dm_lock, PVFS, "devfs", 0, LK_NOPAUSE);
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mp->mnt_flag |= MNT_LOCAL;
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mp->mnt_data = (qaddr_t) fmp;
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vfs_getnewfsid(mp);
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fmp->dm_inode = DEVFSINOMOUNT;
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fmp->dm_rootdir = devfs_vmkdir("(root)", 6, NULL);
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fmp->dm_rootdir->de_inode = 2;
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fmp->dm_basedir = fmp->dm_rootdir;
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error = devfs_root(mp, &rvp);
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if (error) {
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lockdestroy(&fmp->dm_lock);
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FREE(fmp, M_DEVFS);
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return (error);
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}
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VOP_UNLOCK(rvp, 0, p);
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bzero(mp->mnt_stat.f_mntfromname, MNAMELEN);
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bcopy("devfs", mp->mnt_stat.f_mntfromname, sizeof("devfs"));
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(void)devfs_statfs(mp, &mp->mnt_stat, p);
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return (0);
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}
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static int
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devfs_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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int error;
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int flags = 0;
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struct devfs_mount *fmp;
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fmp = VFSTODEVFS(mp);
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if (mntflags & MNT_FORCE)
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flags |= FORCECLOSE;
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/* There is 1 extra root vnode reference from devfs_mount(). */
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error = vflush(mp, 1, flags);
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if (error)
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return (error);
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devfs_purge(fmp->dm_rootdir);
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mp->mnt_data = 0;
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lockdestroy(&fmp->dm_lock);
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free(fmp, M_DEVFS);
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return 0;
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}
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/* Return locked reference to root. */
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static int
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devfs_root(mp, vpp)
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struct mount *mp;
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struct vnode **vpp;
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{
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int error;
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struct proc *p;
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struct vnode *vp;
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struct devfs_mount *dmp;
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p = curproc; /* XXX */
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dmp = VFSTODEVFS(mp);
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error = devfs_allocv(dmp->dm_rootdir, mp, &vp, p);
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if (error)
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return (error);
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vp->v_flag |= VROOT;
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*vpp = vp;
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return (0);
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}
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static int
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devfs_statfs(mp, sbp, p)
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struct mount *mp;
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struct statfs *sbp;
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struct proc *p;
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{
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sbp->f_flags = 0;
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sbp->f_bsize = DEV_BSIZE;
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sbp->f_iosize = DEV_BSIZE;
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sbp->f_blocks = 2; /* 1K to keep df happy */
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sbp->f_bfree = 0;
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sbp->f_bavail = 0;
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sbp->f_files = 0;
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sbp->f_ffree = 0;
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if (sbp != &mp->mnt_stat) {
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sbp->f_type = mp->mnt_vfc->vfc_typenum;
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bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
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bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
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bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
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}
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return (0);
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}
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static struct vfsops devfs_vfsops = {
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devfs_mount,
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vfs_stdstart,
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devfs_unmount,
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devfs_root,
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vfs_stdquotactl,
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devfs_statfs,
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vfs_stdsync,
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vfs_stdvget,
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vfs_stdfhtovp,
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vfs_stdcheckexp,
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vfs_stdvptofh,
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vfs_stdinit,
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vfs_stduninit,
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vfs_stdextattrctl,
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};
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VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC);
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#endif
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