NetBSD-5.0.2/sys/miscfs/overlay/overlay_vfsops.c
/* $NetBSD: overlay_vfsops.c,v 1.53 2008/06/28 01:34:06 rumble Exp $ */
/*
* Copyright (c) 1999, 2000 National Aeronautics & Space Administration
* All rights reserved.
*
* This software was written by William Studenmund of the
* Numerical Aerospace Simulation Facility, NASA Ames Research Center.
*
* 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.
* 3. Neither the name of the National Aeronautics & Space Administration
* 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 NATIONAL AERONAUTICS & SPACE ADMINISTRATION
* ``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 ADMINISTRATION OR CONTRIB-
* UTORS 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.
*/
/*
* 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.
* 3. 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.
*
* from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp
* from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
* @(#)null_vfsops.c 8.7 (Berkeley) 5/14/95
*/
/*
* Overlay Layer
* (See overlay_vnops.c for a description of what this does.)
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: overlay_vfsops.c,v 1.53 2008/06/28 01:34:06 rumble Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <miscfs/overlay/overlay.h>
#include <miscfs/genfs/layer_extern.h>
MODULE(MODULE_CLASS_VFS, overlay, NULL);
VFS_PROTOS(ov);
static struct sysctllog *overlay_sysctl_log;
#define NOVERLAYNODECACHE 16
/*
* Mount overlay layer
*/
int
ov_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
{
struct lwp *l = curlwp;
int error = 0;
struct overlay_args *args = data;
struct vnode *lowerrootvp, *vp;
struct overlay_mount *nmp;
struct layer_mount *lmp;
#ifdef OVERLAYFS_DIAGNOSTIC
printf("ov_mount(mp = %p)\n", mp);
#endif
if (*data_len < sizeof *args)
return EINVAL;
if (mp->mnt_flag & MNT_GETARGS) {
lmp = MOUNTTOLAYERMOUNT(mp);
if (lmp == NULL)
return EIO;
args->la.target = NULL;
*data_len = sizeof *args;
return 0;
}
/*
* Update is not supported
*/
if (mp->mnt_flag & MNT_UPDATE)
return EOPNOTSUPP;
/*
* Find lower node
*/
lowerrootvp = mp->mnt_vnodecovered;
if ((error = vget(lowerrootvp, LK_EXCLUSIVE | LK_RETRY)))
return (error);
/*
* First cut at fixing up upper mount point
*/
nmp = (struct overlay_mount *) malloc(sizeof(struct overlay_mount),
M_UFSMNT, M_WAITOK); /* XXX */
memset(nmp, 0, sizeof(struct overlay_mount));
mp->mnt_data = nmp;
nmp->ovm_vfs = lowerrootvp->v_mount;
if (nmp->ovm_vfs->mnt_flag & MNT_LOCAL)
mp->mnt_flag |= MNT_LOCAL;
/*
* Make sure that the mount point is sufficiently initialized
* that the node create call will work.
*/
vfs_getnewfsid(mp);
nmp->ovm_size = sizeof (struct overlay_node);
nmp->ovm_tag = VT_OVERLAY;
nmp->ovm_bypass = layer_bypass;
nmp->ovm_alloc = layer_node_alloc; /* the default alloc is fine */
nmp->ovm_vnodeop_p = overlay_vnodeop_p;
mutex_init(&nmp->ovm_hashlock, MUTEX_DEFAULT, IPL_NONE);
nmp->ovm_node_hashtbl = hashinit(NOVERLAYNODECACHE, HASH_LIST, true,
&nmp->ovm_node_hash);
/*
* Fix up overlay node for root vnode
*/
error = layer_node_create(mp, lowerrootvp, &vp);
/*
* Make sure the fixup worked
*/
if (error) {
vput(lowerrootvp);
hashdone(nmp->ovm_node_hashtbl, HASH_LIST, nmp->ovm_node_hash);
free(nmp, M_UFSMNT); /* XXX */
return (error);
}
/*
* Unlock the node
*/
VOP_UNLOCK(vp, 0);
/*
* Keep a held reference to the root vnode.
* It is vrele'd in ov_unmount.
*/
vp->v_vflag |= VV_ROOT;
nmp->ovm_rootvp = vp;
error = set_statvfs_info(path, UIO_USERSPACE, args->la.target,
UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
#ifdef OVERLAYFS_DIAGNOSTIC
printf("ov_mount: lower %s, alias at %s\n",
mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
#endif
return error;
}
/*
* Free reference to overlay layer
*/
int
ov_unmount(struct mount *mp, int mntflags)
{
struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp;
struct overlay_mount *omp;
int error;
int flags = 0;
#ifdef OVERLAYFS_DIAGNOSTIC
printf("ov_unmount(mp = %p)\n", mp);
#endif
if (mntflags & MNT_FORCE)
flags |= FORCECLOSE;
if (overlay_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0)
return (EBUSY);
if ((error = vflush(mp, overlay_rootvp, flags)) != 0)
return (error);
#ifdef OVERLAYFS_DIAGNOSTIC
vprint("alias root of lower", overlay_rootvp);
#endif
/*
* Blow it away for future re-use
*/
vgone(overlay_rootvp);
/*
* Finally, throw away the overlay_mount structure
*/
omp = mp->mnt_data;
mutex_destroy(&omp->ovm_hashlock);
hashdone(omp->ovm_node_hashtbl, HASH_LIST, omp->ovm_node_hash);
free(omp, M_UFSMNT); /* XXX */
mp->mnt_data = NULL;
return 0;
}
extern const struct vnodeopv_desc overlay_vnodeop_opv_desc;
const struct vnodeopv_desc * const ov_vnodeopv_descs[] = {
&overlay_vnodeop_opv_desc,
NULL,
};
struct vfsops overlay_vfsops = {
MOUNT_OVERLAY,
sizeof (struct overlay_args),
ov_mount,
layerfs_start,
ov_unmount,
layerfs_root,
layerfs_quotactl,
layerfs_statvfs,
layerfs_sync,
layerfs_vget,
layerfs_fhtovp,
layerfs_vptofh,
layerfs_init,
NULL,
layerfs_done,
NULL, /* vfs_mountroot */
layerfs_snapshot,
vfs_stdextattrctl,
(void *)eopnotsupp, /* vfs_suspendctl */
layerfs_renamelock_enter,
layerfs_renamelock_exit,
(void *)eopnotsupp,
ov_vnodeopv_descs,
0,
{ NULL, NULL },
};
static int
overlay_modcmd(modcmd_t cmd, void *arg)
{
int error;
switch (cmd) {
case MODULE_CMD_INIT:
error = vfs_attach(&overlay_vfsops);
if (error != 0)
break;
sysctl_createv(&overlay_sysctl_log, 0, NULL, NULL,
CTLFLAG_PERMANENT, CTLTYPE_NODE, "vfs", NULL,
NULL, 0, NULL, 0,
CTL_VFS, CTL_EOL);
sysctl_createv(&overlay_sysctl_log, 0, NULL, NULL,
CTLFLAG_PERMANENT, CTLTYPE_NODE, "overlay",
SYSCTL_DESCR("Overlay file system"),
NULL, 0, NULL, 0,
CTL_VFS, CTL_CREATE, CTL_EOL);
break;
case MODULE_CMD_FINI:
error = vfs_detach(&overlay_vfsops);
if (error != 0)
break;
sysctl_teardown(&overlay_sysctl_log);
break;
default:
error = ENOTTY;
break;
}
return (error);
}