FreeBSD-5.3/sys/fs/nullfs/null_vfsops.c
/*
* Copyright (c) 1992, 1993, 1995
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software donated to Berkeley by
* Jan-Simon Pendry.
*
* 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94
*
* @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
* $FreeBSD: src/sys/fs/nullfs/null_vfsops.c,v 1.63 2004/07/30 22:08:50 phk Exp $
*/
/*
* Null Layer
* (See null_vnops.c for a description of what this does.)
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <fs/nullfs/null.h>
static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure");
static vfs_fhtovp_t nullfs_fhtovp;
static vfs_checkexp_t nullfs_checkexp;
static vfs_mount_t nullfs_mount;
static vfs_quotactl_t nullfs_quotactl;
static vfs_root_t nullfs_root;
static vfs_start_t nullfs_start;
static vfs_sync_t nullfs_sync;
static vfs_statfs_t nullfs_statfs;
static vfs_unmount_t nullfs_unmount;
static vfs_vget_t nullfs_vget;
static vfs_vptofh_t nullfs_vptofh;
static vfs_extattrctl_t nullfs_extattrctl;
/*
* Mount null layer
*/
static int
nullfs_mount(struct mount *mp, struct thread *td)
{
int error = 0;
struct vnode *lowerrootvp, *vp;
struct vnode *nullm_rootvp;
struct null_mount *xmp;
char *target;
size_t size;
int isvnunlocked = 0, len;
struct nameidata nd, *ndp = &nd;
NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
/*
* Update is a no-op
*/
if (mp->mnt_flag & MNT_UPDATE) {
return (EOPNOTSUPP);
/* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, td);*/
}
/*
* Get argument
*/
error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len);
if (error || target[len - 1] != '\0')
return (EINVAL);
/*
* Unlock lower node to avoid deadlock.
* (XXX) VOP_ISLOCKED is needed?
*/
if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) &&
VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) {
VOP_UNLOCK(mp->mnt_vnodecovered, 0, td);
isvnunlocked = 1;
}
/*
* Find lower node
*/
NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF,
UIO_SYSSPACE, target, td);
error = namei(ndp);
/*
* Re-lock vnode.
*/
if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL))
vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td);
if (error)
return (error);
NDFREE(ndp, NDF_ONLY_PNBUF);
/*
* Sanity check on lower vnode
*/
lowerrootvp = ndp->ni_vp;
vrele(ndp->ni_dvp);
ndp->ni_dvp = NULLVP;
/*
* Check multi null mount to avoid `lock against myself' panic.
*/
if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
NULLFSDEBUG("nullfs_mount: multi null mount?\n");
vput(lowerrootvp);
return (EDEADLK);
}
xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
M_NULLFSMNT, M_WAITOK); /* XXX */
/*
* Save reference to underlying FS
*/
xmp->nullm_vfs = lowerrootvp->v_mount;
/*
* Save reference. Each mount also holds
* a reference on the root vnode.
*/
error = null_nodeget(mp, lowerrootvp, &vp);
/*
* Make sure the node alias worked
*/
if (error) {
VOP_UNLOCK(vp, 0, td);
vrele(lowerrootvp);
free(xmp, M_NULLFSMNT); /* XXX */
return (error);
}
/*
* Keep a held reference to the root vnode.
* It is vrele'd in nullfs_unmount.
*/
nullm_rootvp = vp;
nullm_rootvp->v_vflag |= VV_ROOT;
xmp->nullm_rootvp = nullm_rootvp;
/*
* Unlock the node (either the lower or the alias)
*/
VOP_UNLOCK(vp, 0, td);
if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
mp->mnt_flag |= MNT_LOCAL;
mp->mnt_data = (qaddr_t) xmp;
vfs_getnewfsid(mp);
(void) copystr(target, mp->mnt_stat.f_mntfromname,
MNAMELEN - 1, &size);
bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
(void)nullfs_statfs(mp, &mp->mnt_stat, td);
NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
return (0);
}
/*
* VFS start. Nothing needed here - the start routine
* on the underlying filesystem will have been called
* when that filesystem was mounted.
*/
static int
nullfs_start(mp, flags, td)
struct mount *mp;
int flags;
struct thread *td;
{
return (0);
/* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */
}
/*
* Free reference to null layer
*/
static int
nullfs_unmount(mp, mntflags, td)
struct mount *mp;
int mntflags;
struct thread *td;
{
void *mntdata;
int error;
int flags = 0;
NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
if (mntflags & MNT_FORCE)
flags |= FORCECLOSE;
/* There is 1 extra root vnode reference (nullm_rootvp). */
error = vflush(mp, 1, flags, td);
if (error)
return (error);
/*
* Finally, throw away the null_mount structure
*/
mntdata = mp->mnt_data;
mp->mnt_data = 0;
free(mntdata, M_NULLFSMNT);
return 0;
}
static int
nullfs_root(mp, vpp, td)
struct mount *mp;
struct vnode **vpp;
struct thread *td;
{
struct vnode *vp;
NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
(void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
(void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
/*
* Return locked reference to root.
*/
vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
VREF(vp);
#ifdef NULLFS_DEBUG
if (VOP_ISLOCKED(vp, NULL)) {
kdb_enter("root vnode is locked.\n");
vrele(vp);
return (EDEADLK);
}
#endif
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
*vpp = vp;
return 0;
}
static int
nullfs_quotactl(mp, cmd, uid, arg, td)
struct mount *mp;
int cmd;
uid_t uid;
caddr_t arg;
struct thread *td;
{
return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td);
}
static int
nullfs_statfs(mp, sbp, td)
struct mount *mp;
struct statfs *sbp;
struct thread *td;
{
int error;
struct statfs mstat;
NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
(void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
(void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
bzero(&mstat, sizeof(mstat));
error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td);
if (error)
return (error);
/* now copy across the "interesting" information and fake the rest */
sbp->f_type = mstat.f_type;
sbp->f_flags = mstat.f_flags;
sbp->f_bsize = mstat.f_bsize;
sbp->f_iosize = mstat.f_iosize;
sbp->f_blocks = mstat.f_blocks;
sbp->f_bfree = mstat.f_bfree;
sbp->f_bavail = mstat.f_bavail;
sbp->f_files = mstat.f_files;
sbp->f_ffree = mstat.f_ffree;
if (sbp != &mp->mnt_stat) {
bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
}
return (0);
}
static int
nullfs_sync(mp, waitfor, cred, td)
struct mount *mp;
int waitfor;
struct ucred *cred;
struct thread *td;
{
/*
* XXX - Assumes no data cached at null layer.
*/
return (0);
}
static int
nullfs_vget(mp, ino, flags, vpp)
struct mount *mp;
ino_t ino;
int flags;
struct vnode **vpp;
{
int error;
error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp);
if (error)
return (error);
return (null_nodeget(mp, *vpp, vpp));
}
static int
nullfs_fhtovp(mp, fidp, vpp)
struct mount *mp;
struct fid *fidp;
struct vnode **vpp;
{
int error;
error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp);
if (error)
return (error);
return (null_nodeget(mp, *vpp, vpp));
}
static int
nullfs_checkexp(mp, nam, extflagsp, credanonp)
struct mount *mp;
struct sockaddr *nam;
int *extflagsp;
struct ucred **credanonp;
{
return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
extflagsp, credanonp);
}
static int
nullfs_vptofh(vp, fhp)
struct vnode *vp;
struct fid *fhp;
{
struct vnode *lvp;
lvp = NULLVPTOLOWERVP(vp);
return VFS_VPTOFH(lvp, fhp);
}
static int
nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, td)
struct mount *mp;
int cmd;
struct vnode *filename_vp;
int namespace;
const char *attrname;
struct thread *td;
{
return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp,
namespace, attrname, td);
}
static struct vfsops null_vfsops = {
.vfs_checkexp = nullfs_checkexp,
.vfs_extattrctl = nullfs_extattrctl,
.vfs_fhtovp = nullfs_fhtovp,
.vfs_init = nullfs_init,
.vfs_mount = nullfs_mount,
.vfs_quotactl = nullfs_quotactl,
.vfs_root = nullfs_root,
.vfs_start = nullfs_start,
.vfs_statfs = nullfs_statfs,
.vfs_sync = nullfs_sync,
.vfs_uninit = nullfs_uninit,
.vfs_unmount = nullfs_unmount,
.vfs_vget = nullfs_vget,
.vfs_vptofh = nullfs_vptofh,
};
VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK);