| Current Path : /usr/src/sys/fs/nullfs/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //usr/src/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: release/9.1.0/sys/fs/nullfs/null_vfsops.c 232728 2012-03-09 16:17:46Z mm $
*/
/*
* Null Layer
* (See null_vnops.c for a description of what this does.)
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fcntl.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 <sys/jail.h>
#include <fs/nullfs/null.h>
static MALLOC_DEFINE(M_NULLFSMNT, "nullfs_mount", "NULLFS mount structure");
static vfs_fhtovp_t nullfs_fhtovp;
static vfs_mount_t nullfs_mount;
static vfs_quotactl_t nullfs_quotactl;
static vfs_root_t nullfs_root;
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_extattrctl_t nullfs_extattrctl;
/*
* Mount null layer
*/
static int
nullfs_mount(struct mount *mp)
{
int error = 0;
struct vnode *lowerrootvp, *vp;
struct vnode *nullm_rootvp;
struct null_mount *xmp;
struct thread *td = curthread;
char *target;
int isvnunlocked = 0, len;
struct nameidata nd, *ndp = &nd;
NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_NULLFS))
return (EPERM);
if (mp->mnt_flag & MNT_ROOTFS)
return (EOPNOTSUPP);
/*
* Update is a no-op
*/
if (mp->mnt_flag & MNT_UPDATE) {
/*
* Only support update mounts for NFS export.
*/
if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
return (0);
else
return (EOPNOTSUPP);
}
/*
* 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 possible deadlock.
*/
if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) &&
VOP_ISLOCKED(mp->mnt_vnodecovered) == LK_EXCLUSIVE) {
VOP_UNLOCK(mp->mnt_vnodecovered, 0);
isvnunlocked = 1;
}
/*
* Find lower node
*/
NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, curthread);
error = namei(ndp);
/*
* Re-lock vnode.
*/
if (isvnunlocked)
vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY);
if (error)
return (error);
NDFREE(ndp, NDF_ONLY_PNBUF);
/*
* Sanity check on lower vnode
*/
lowerrootvp = ndp->ni_vp;
/*
* 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) {
free(xmp, M_NULLFSMNT);
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);
if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) {
MNT_ILOCK(mp);
mp->mnt_flag |= MNT_LOCAL;
MNT_IUNLOCK(mp);
}
MNT_ILOCK(mp);
mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag &
(MNTK_MPSAFE | MNTK_SHARED_WRITES);
MNT_IUNLOCK(mp);
mp->mnt_data = xmp;
vfs_getnewfsid(mp);
vfs_mountedfrom(mp, target);
NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
return (0);
}
/*
* Free reference to null layer
*/
static int
nullfs_unmount(mp, mntflags)
struct mount *mp;
int mntflags;
{
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, curthread);
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, flags, vpp)
struct mount *mp;
int flags;
struct vnode **vpp;
{
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);
ASSERT_VOP_UNLOCKED(vp, "root vnode is locked");
vn_lock(vp, flags | LK_RETRY);
*vpp = vp;
return 0;
}
static int
nullfs_quotactl(mp, cmd, uid, arg)
struct mount *mp;
int cmd;
uid_t uid;
void *arg;
{
return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg);
}
static int
nullfs_statfs(mp, sbp)
struct mount *mp;
struct statfs *sbp;
{
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);
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;
return (0);
}
static int
nullfs_sync(mp, waitfor)
struct mount *mp;
int waitfor;
{
/*
* 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;
KASSERT((flags & LK_TYPE_MASK) != 0,
("nullfs_vget: no lock requested"));
flags &= ~LK_TYPE_MASK;
flags |= LK_EXCLUSIVE;
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, flags, vpp)
struct mount *mp;
struct fid *fidp;
int flags;
struct vnode **vpp;
{
int error;
error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, LK_EXCLUSIVE,
vpp);
if (error)
return (error);
return (null_nodeget(mp, *vpp, vpp));
}
static int
nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname)
struct mount *mp;
int cmd;
struct vnode *filename_vp;
int namespace;
const char *attrname;
{
return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp,
namespace, attrname);
}
static struct vfsops null_vfsops = {
.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_statfs = nullfs_statfs,
.vfs_sync = nullfs_sync,
.vfs_uninit = nullfs_uninit,
.vfs_unmount = nullfs_unmount,
.vfs_vget = nullfs_vget,
};
VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK | VFCF_JAIL);