551 lines
13 KiB
C
551 lines
13 KiB
C
/*
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* Copyright (c) 1994 The Regents of the University of California.
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* Copyright (c) 1994 Jan-Simon Pendry.
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* 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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* @(#)union_vfsops.c 8.7 (Berkeley) 3/5/94
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*/
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/*
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* Union Layer
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*/
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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/types.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/filedesc.h>
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#include <sys/queue.h>
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#include <miscfs/union/union.h>
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/*
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* Mount union filesystem
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*/
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int
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union_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 = 0;
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struct union_args args;
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struct vnode *lowerrootvp = NULLVP;
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struct vnode *upperrootvp = NULLVP;
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struct union_mount *um;
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struct ucred *cred = 0;
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struct ucred *scred;
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struct vattr va;
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char *cp = 0;
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int len;
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u_int size;
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#ifdef UNION_DIAGNOSTIC
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printf("union_mount(mp = %x)\n", mp);
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#endif
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/*
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* Update is a no-op
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*/
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if (mp->mnt_flag & MNT_UPDATE) {
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/*
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* Need to provide.
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* 1. a way to convert between rdonly and rdwr mounts.
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* 2. support for nfs exports.
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*/
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error = EOPNOTSUPP;
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goto bad;
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}
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/*
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* Take a copy of the process's credentials. This isn't
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* quite right since the euid will always be zero and we
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* want to get the "real" users credentials. So fix up
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* the uid field after taking the copy.
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*/
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cred = crdup(p->p_ucred);
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cred->cr_uid = p->p_cred->p_ruid;
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/*
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* Ensure the *real* user has write permission on the
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* mounted-on directory. This allows the mount_union
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* command to be made setuid root so allowing anyone
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* to do union mounts onto any directory on which they
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* have write permission and which they also own.
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*/
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error = VOP_GETATTR(mp->mnt_vnodecovered, &va, cred, p);
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if (error)
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goto bad;
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if ((va.va_uid != cred->cr_uid) &&
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(cred->cr_uid != 0)) {
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error = EACCES;
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goto bad;
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}
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error = VOP_ACCESS(mp->mnt_vnodecovered, VWRITE, cred, p);
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if (error)
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goto bad;
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/*
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* Get argument
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*/
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if (error = copyin(data, (caddr_t)&args, sizeof(struct union_args)))
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goto bad;
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lowerrootvp = mp->mnt_vnodecovered;
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VREF(lowerrootvp);
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/*
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* Find upper node. Use the real process credentials,
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* not the effective ones since this will have come
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* through a setuid process (mount_union). All this
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* messing around with permissions is entirely bogus
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* and should be removed by allowing any user straight
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* past the mount system call.
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*/
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scred = p->p_ucred;
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p->p_ucred = cred;
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NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT,
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UIO_USERSPACE, args.target, p);
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p->p_ucred = scred;
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if (error = namei(ndp))
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goto bad;
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upperrootvp = ndp->ni_vp;
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vrele(ndp->ni_dvp);
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ndp->ni_dvp = NULL;
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if (upperrootvp->v_type != VDIR) {
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error = EINVAL;
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goto bad;
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}
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um = (struct union_mount *) malloc(sizeof(struct union_mount),
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M_UFSMNT, M_WAITOK); /* XXX */
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/*
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* Keep a held reference to the target vnodes.
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* They are vrele'd in union_unmount.
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*
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* Depending on the _BELOW flag, the filesystems are
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* viewed in a different order. In effect, this is the
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* same as providing a mount under option to the mount syscall.
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*/
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um->um_op = args.mntflags & UNMNT_OPMASK;
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switch (um->um_op) {
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case UNMNT_ABOVE:
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um->um_lowervp = lowerrootvp;
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um->um_uppervp = upperrootvp;
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break;
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case UNMNT_BELOW:
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um->um_lowervp = upperrootvp;
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um->um_uppervp = lowerrootvp;
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break;
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case UNMNT_REPLACE:
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vrele(lowerrootvp);
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lowerrootvp = NULLVP;
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um->um_uppervp = upperrootvp;
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um->um_lowervp = lowerrootvp;
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break;
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default:
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error = EINVAL;
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goto bad;
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}
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um->um_cred = cred;
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um->um_cmode = UN_DIRMODE &~ p->p_fd->fd_cmask;
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/*
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* Depending on what you think the MNT_LOCAL flag might mean,
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* you may want the && to be || on the conditional below.
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* At the moment it has been defined that the filesystem is
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* only local if it is all local, ie the MNT_LOCAL flag implies
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* that the entire namespace is local. If you think the MNT_LOCAL
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* flag implies that some of the files might be stored locally
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* then you will want to change the conditional.
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*/
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if (um->um_op == UNMNT_ABOVE) {
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if (((um->um_lowervp == NULLVP) ||
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(um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) &&
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(um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
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mp->mnt_flag |= MNT_LOCAL;
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}
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/*
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* Copy in the upper layer's RDONLY flag. This is for the benefit
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* of lookup() which explicitly checks the flag, rather than asking
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* the filesystem for it's own opinion. This means, that an update
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* mount of the underlying filesystem to go from rdonly to rdwr
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* will leave the unioned view as read-only.
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*/
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mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY);
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/*
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* This is a user mount. Privilege check for unmount
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* will be done in union_unmount.
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*/
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mp->mnt_flag |= MNT_USER;
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mp->mnt_data = (qaddr_t) um;
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getnewfsid(mp, MOUNT_UNION);
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(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
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bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
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switch (um->um_op) {
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case UNMNT_ABOVE:
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cp = "<above>";
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break;
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case UNMNT_BELOW:
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cp = "<below>";
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break;
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case UNMNT_REPLACE:
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cp = "";
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break;
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}
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len = strlen(cp);
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bcopy(cp, mp->mnt_stat.f_mntfromname, len);
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cp = mp->mnt_stat.f_mntfromname + len;
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len = MNAMELEN - len;
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(void) copyinstr(args.target, cp, len - 1, &size);
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bzero(cp + size, len - size);
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#ifdef UNION_DIAGNOSTIC
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printf("union_mount: from %s, on %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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bad:
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if (cred)
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crfree(cred);
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if (upperrootvp)
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vrele(upperrootvp);
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if (lowerrootvp)
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vrele(lowerrootvp);
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return (error);
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}
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/*
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* VFS start. Nothing needed here - the start routine
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* on the underlying filesystem(s) will have been called
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* when that filesystem was mounted.
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*/
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int
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union_start(mp, flags, p)
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struct mount *mp;
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int flags;
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struct proc *p;
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{
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return (0);
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}
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/*
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* Free reference to union layer
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*/
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int
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union_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 union_mount *um = MOUNTTOUNIONMOUNT(mp);
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struct vnode *um_rootvp;
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int error;
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int flags = 0;
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extern int doforce;
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#ifdef UNION_DIAGNOSTIC
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printf("union_unmount(mp = %x)\n", mp);
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#endif
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/* only the mounter, or superuser can unmount */
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if ((p->p_cred->p_ruid != um->um_cred->cr_uid) &&
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(error = suser(p->p_ucred, &p->p_acflag)))
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return (error);
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if (mntflags & MNT_FORCE) {
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/* union can never be rootfs so don't check for it */
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if (!doforce)
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return (EINVAL);
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flags |= FORCECLOSE;
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}
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if (error = union_root(mp, &um_rootvp))
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return (error);
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if (um_rootvp->v_usecount > 1) {
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vput(um_rootvp);
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return (EBUSY);
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}
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if (error = vflush(mp, um_rootvp, flags)) {
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vput(um_rootvp);
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return (error);
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}
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#ifdef UNION_DIAGNOSTIC
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vprint("alias root of lower", um_rootvp);
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#endif
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/*
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* Discard references to upper and lower target vnodes.
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*/
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if (um->um_lowervp)
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vrele(um->um_lowervp);
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vrele(um->um_uppervp);
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crfree(um->um_cred);
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/*
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* Release reference on underlying root vnode
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*/
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vput(um_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(um_rootvp);
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/*
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* Finally, throw away the union_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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int
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union_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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struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
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int error;
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int loselock;
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#ifdef UNION_DIAGNOSTIC
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printf("union_root(mp = %x, lvp = %x, uvp = %x)\n", mp,
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um->um_lowervp,
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um->um_uppervp);
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#endif
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/*
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* Return locked reference to root.
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*/
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VREF(um->um_uppervp);
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if ((um->um_op == UNMNT_BELOW) &&
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VOP_ISLOCKED(um->um_uppervp)) {
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loselock = 1;
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} else {
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VOP_LOCK(um->um_uppervp);
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loselock = 0;
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}
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if (um->um_lowervp)
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VREF(um->um_lowervp);
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error = union_allocvp(vpp, mp,
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(struct vnode *) 0,
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(struct vnode *) 0,
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(struct componentname *) 0,
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um->um_uppervp,
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um->um_lowervp);
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if (error) {
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if (!loselock)
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VOP_UNLOCK(um->um_uppervp);
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vrele(um->um_uppervp);
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if (um->um_lowervp)
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vrele(um->um_lowervp);
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} else {
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(*vpp)->v_flag |= VROOT;
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if (loselock)
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VTOUNION(*vpp)->un_flags &= ~UN_ULOCK;
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}
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return (error);
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}
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int
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union_quotactl(mp, cmd, uid, arg, p)
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struct mount *mp;
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int cmd;
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uid_t uid;
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caddr_t arg;
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struct proc *p;
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{
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return (EOPNOTSUPP);
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}
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int
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union_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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int error;
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struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
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struct statfs mstat;
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int lbsize;
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#ifdef UNION_DIAGNOSTIC
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printf("union_statfs(mp = %x, lvp = %x, uvp = %x)\n", mp,
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um->um_lowervp,
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um->um_uppervp);
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#endif
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bzero(&mstat, sizeof(mstat));
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if (um->um_lowervp) {
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error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, p);
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if (error)
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return (error);
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}
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/* now copy across the "interesting" information and fake the rest */
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#if 0
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sbp->f_type = mstat.f_type;
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sbp->f_flags = mstat.f_flags;
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sbp->f_bsize = mstat.f_bsize;
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sbp->f_iosize = mstat.f_iosize;
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#endif
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lbsize = mstat.f_bsize;
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sbp->f_blocks = mstat.f_blocks;
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sbp->f_bfree = mstat.f_bfree;
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sbp->f_bavail = mstat.f_bavail;
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sbp->f_files = mstat.f_files;
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sbp->f_ffree = mstat.f_ffree;
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error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, p);
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if (error)
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return (error);
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sbp->f_type = MOUNT_UNION;
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sbp->f_flags = mstat.f_flags;
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sbp->f_bsize = mstat.f_bsize;
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sbp->f_iosize = mstat.f_iosize;
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/*
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* if the lower and upper blocksizes differ, then frig the
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* block counts so that the sizes reported by df make some
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* kind of sense. none of this makes sense though.
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*/
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if (mstat.f_bsize != lbsize) {
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sbp->f_blocks = sbp->f_blocks * lbsize / mstat.f_bsize;
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sbp->f_bfree = sbp->f_bfree * lbsize / mstat.f_bsize;
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sbp->f_bavail = sbp->f_bavail * lbsize / mstat.f_bsize;
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}
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sbp->f_blocks += mstat.f_blocks;
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sbp->f_bfree += mstat.f_bfree;
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sbp->f_bavail += mstat.f_bavail;
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sbp->f_files += mstat.f_files;
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sbp->f_ffree += mstat.f_ffree;
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if (sbp != &mp->mnt_stat) {
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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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int
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union_sync(mp, waitfor, cred, p)
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struct mount *mp;
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int waitfor;
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struct ucred *cred;
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struct proc *p;
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{
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/*
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* XXX - Assumes no data cached at union layer.
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*/
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return (0);
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}
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int
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union_vget(mp, ino, vpp)
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struct mount *mp;
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ino_t ino;
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struct vnode **vpp;
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{
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return (EOPNOTSUPP);
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}
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int
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union_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp)
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struct mount *mp;
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struct fid *fidp;
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struct mbuf *nam;
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struct vnode **vpp;
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int *exflagsp;
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struct ucred **credanonp;
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{
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return (EOPNOTSUPP);
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}
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int
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union_vptofh(vp, fhp)
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struct vnode *vp;
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struct fid *fhp;
|
|
{
|
|
|
|
return (EOPNOTSUPP);
|
|
}
|
|
|
|
int union_init __P((void));
|
|
|
|
struct vfsops union_vfsops = {
|
|
union_mount,
|
|
union_start,
|
|
union_unmount,
|
|
union_root,
|
|
union_quotactl,
|
|
union_statfs,
|
|
union_sync,
|
|
union_vget,
|
|
union_fhtovp,
|
|
union_vptofh,
|
|
union_init,
|
|
};
|