8d041ea733
... to ensure that we have a valid mountpoint during the call. Reviewed by: kib MFC after: 19 days
116 lines
3.1 KiB
C
116 lines
3.1 KiB
C
/*-
|
|
* Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/pathname.h>
|
|
#include <sys/vfs.h>
|
|
#include <sys/vnode.h>
|
|
|
|
int
|
|
lookupname(char *dirname, enum uio_seg seg, enum symfollow follow,
|
|
vnode_t **dirvpp, vnode_t **compvpp)
|
|
{
|
|
|
|
return (lookupnameat(dirname, seg, follow, dirvpp, compvpp, NULL));
|
|
}
|
|
|
|
int
|
|
lookupnameat(char *dirname, enum uio_seg seg, enum symfollow follow,
|
|
vnode_t **dirvpp, vnode_t **compvpp, vnode_t *startvp)
|
|
{
|
|
struct nameidata nd;
|
|
int error, ltype;
|
|
|
|
ASSERT(dirvpp == NULL);
|
|
|
|
vref(startvp);
|
|
ltype = VOP_ISLOCKED(startvp);
|
|
VOP_UNLOCK(startvp, 0);
|
|
NDINIT_ATVP(&nd, LOOKUP, LOCKLEAF | follow, seg, dirname,
|
|
startvp, curthread);
|
|
error = namei(&nd);
|
|
*compvpp = nd.ni_vp;
|
|
NDFREE(&nd, NDF_ONLY_PNBUF);
|
|
vn_lock(startvp, ltype | LK_RETRY);
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
traverse(vnode_t **cvpp, int lktype)
|
|
{
|
|
vnode_t *cvp;
|
|
vnode_t *tvp;
|
|
vfs_t *vfsp;
|
|
int error;
|
|
|
|
cvp = *cvpp;
|
|
tvp = NULL;
|
|
|
|
/*
|
|
* If this vnode is mounted on, then we transparently indirect
|
|
* to the vnode which is the root of the mounted file system.
|
|
* Before we do this we must check that an unmount is not in
|
|
* progress on this vnode.
|
|
*/
|
|
|
|
for (;;) {
|
|
/*
|
|
* Reached the end of the mount chain?
|
|
*/
|
|
vfsp = vn_mountedvfs(cvp);
|
|
if (vfsp == NULL)
|
|
break;
|
|
error = vfs_busy(vfsp, 0);
|
|
/*
|
|
* tvp is NULL for *cvpp vnode, which we can't unlock.
|
|
*/
|
|
if (tvp != NULL)
|
|
vput(cvp);
|
|
else
|
|
vrele(cvp);
|
|
if (error)
|
|
return (error);
|
|
|
|
/*
|
|
* The read lock must be held across the call to VFS_ROOT() to
|
|
* prevent a concurrent unmount from destroying the vfs.
|
|
*/
|
|
error = VFS_ROOT(vfsp, lktype, &tvp);
|
|
vfs_unbusy(vfsp);
|
|
if (error != 0)
|
|
return (error);
|
|
cvp = tvp;
|
|
}
|
|
|
|
*cvpp = cvp;
|
|
return (0);
|
|
}
|