NetBSD/sys/fs/unionfs/unionfs_vfsops.c

589 lines
13 KiB
C

/*-
* Copyright (c) 1994, 1995 The Regents of the University of California.
* Copyright (c) 1994, 1995 Jan-Simon Pendry.
* Copyright (c) 2005, 2006 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc.
* Copyright (c) 2006 Daichi Goto <daichi@freebsd.org>
* 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.
*
* @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95
* $FreeBSD: src/sys/fs/unionfs/union_vfsops.c,v 1.89 2008/01/13 14:44:06 attilio Exp $
*/
#include <sys/param.h>
#include <sys/systm.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/stat.h>
#include <sys/sysctl.h>
#include <sys/module.h>
#include <fs/unionfs/unionfs.h>
MODULE(MODULE_CLASS_VFS, unionfs, "layerfs");
MALLOC_DEFINE(M_UNIONFSMNT, "UNIONFS mount", "UNIONFS mount structure");
struct vfsops unionfs_vfsops;
VFS_PROTOS(unionfs);
static struct sysctllog *unionfs_sysctl_log;
/*
* Mount unionfs layer.
*/
int
unionfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
{
int error;
struct vnode *lowerrootvp;
struct vnode *upperrootvp;
struct unionfs_mount *ump;
int below;
uid_t uid;
gid_t gid;
u_short udir;
u_short ufile;
unionfs_copymode copymode;
unionfs_whitemode whitemode;
struct pathbuf *pb;
struct componentname fakecn;
struct nameidata nd, *ndp;
struct vattr va;
struct union_args *args = data;
kauth_cred_t cred;
size_t size;
size_t len;
const char *cp;
char *xp;
if (*data_len < sizeof *args)
return EINVAL;
UNIONFSDEBUG("unionfs_mount(mp = %p)\n", (void *)mp);
error = 0;
below = 0;
uid = 0;
gid = 0;
udir = 0;
ufile = 0;
copymode = UNIONFS_TRANSPARENT; /* default */
whitemode = UNIONFS_WHITE_ALWAYS;
ndp = &nd;
cred = kauth_cred_get();
if (mp->mnt_flag & MNT_ROOTFS) {
printf("union_mount: cannot union mount root filesystem\n");
return (EOPNOTSUPP);
}
if (mp->mnt_flag & MNT_GETARGS) {
ump = MOUNTTOUNIONFSMOUNT(mp);
if (ump == NULL)
return EIO;
args->target = NULL;
args->mntflags = ump->um_op;
*data_len = sizeof *args;
return 0;
}
/*
* Update is a no operation.
*/
if (mp->mnt_flag & MNT_UPDATE) {
printf("union_mount: cannot update union mount\n");
return (EOPNOTSUPP);
}
vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY);
error = VOP_GETATTR(mp->mnt_vnodecovered, &va, cred);
if (!error) {
if (udir == 0)
udir = va.va_mode;
if (ufile == 0)
ufile = va.va_mode;
uid = va.va_uid;
gid = va.va_gid;
}
VOP_UNLOCK(mp->mnt_vnodecovered);
if (error)
return (error);
switch (args->mntflags & UNMNT_OPMASK) {
case UNMNT_ABOVE:
below = 0;
break;
case UNMNT_BELOW:
below = 1;
break;
case UNMNT_REPLACE:
default:
return EINVAL;
}
/* If copymode is UNIONFS_TRADITIONAL, uid/gid is mounted user. */
if (copymode == UNIONFS_TRADITIONAL) {
uid = kauth_cred_getuid(cred);
gid = kauth_cred_getgid(cred);
}
UNIONFSDEBUG("unionfs_mount: uid=%d, gid=%d\n", uid, gid);
UNIONFSDEBUG("unionfs_mount: udir=0%03o, ufile=0%03o\n", udir, ufile);
UNIONFSDEBUG("unionfs_mount: copymode=%d\n", copymode);
/*
* Find upper node
*/
error = pathbuf_copyin(args->target, &pb);
if (error) {
return error;
}
NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF, pb);
if ((error = namei(ndp))) {
pathbuf_destroy(pb);
return error;
}
/* get root vnodes */
lowerrootvp = mp->mnt_vnodecovered;
upperrootvp = ndp->ni_vp;
vrele(ndp->ni_dvp);
ndp->ni_dvp = NULLVP;
pathbuf_destroy(pb);
/* create unionfs_mount */
ump = (struct unionfs_mount *)malloc(sizeof(struct unionfs_mount),
M_UNIONFSMNT, M_WAITOK | M_ZERO);
/*
* Save reference
*/
if (below) {
VOP_UNLOCK(upperrootvp);
vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY);
ump->um_lowervp = upperrootvp;
ump->um_uppervp = lowerrootvp;
} else {
ump->um_lowervp = lowerrootvp;
ump->um_uppervp = upperrootvp;
}
ump->um_rootvp = NULLVP;
ump->um_uid = uid;
ump->um_gid = gid;
ump->um_udir = udir;
ump->um_ufile = ufile;
ump->um_copymode = copymode;
ump->um_whitemode = whitemode;
if ((lowerrootvp->v_mount->mnt_iflag & IMNT_MPSAFE) &&
(upperrootvp->v_mount->mnt_flag & IMNT_MPSAFE))
mp->mnt_iflag |= IMNT_MPSAFE;
mp->mnt_data = ump;
/*
* Copy upper layer's RDONLY flag.
*/
mp->mnt_flag |= ump->um_uppervp->v_mount->mnt_flag & MNT_RDONLY;
/*
* Check whiteout
*/
if ((mp->mnt_flag & MNT_RDONLY) == 0) {
memset(&fakecn, 0, sizeof(fakecn));
fakecn.cn_nameiop = LOOKUP;
error = VOP_WHITEOUT(ump->um_uppervp, &fakecn, LOOKUP);
if (error) {
if (below) {
VOP_UNLOCK(ump->um_uppervp);
vrele(upperrootvp);
} else
vput(ump->um_uppervp);
free(ump, M_UNIONFSMNT);
mp->mnt_data = NULL;
return (error);
}
}
/*
* Unlock the node
*/
VOP_UNLOCK(ump->um_uppervp);
ump->um_op = args->mntflags & UNMNT_OPMASK;
/*
* Get the unionfs root vnode.
*/
error = unionfs_nodeget(mp, ump->um_uppervp, ump->um_lowervp,
NULLVP, &(ump->um_rootvp), NULL);
vrele(upperrootvp);
if (error) {
free(ump, M_UNIONFSMNT);
mp->mnt_data = NULL;
return (error);
}
/*
* Check mnt_flag
*/
if ((ump->um_lowervp->v_mount->mnt_flag & MNT_LOCAL) &&
(ump->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
mp->mnt_flag |= MNT_LOCAL;
/*
* Get new fsid
*/
vfs_getnewfsid(mp);
error = set_statvfs_info(path, UIO_USERSPACE, NULL, UIO_USERSPACE,
mp->mnt_op->vfs_name, mp, curlwp);
if (error) {
unionfs_noderem(ump->um_rootvp);
free(ump, M_UNIONFSMNT);
mp->mnt_data = NULL;
return (error);
}
switch (ump->um_op) {
case UNMNT_ABOVE:
cp = "<above>:";
break;
case UNMNT_BELOW:
cp = "<below>:";
break;
default:
panic("union_mount: bad um_op");
break;
}
len = strlen(cp);
memcpy(mp->mnt_stat.f_mntfromname, cp, len);
xp = mp->mnt_stat.f_mntfromname + len;
len = MNAMELEN - len;
(void) copyinstr(args->target, xp, len - 1, &size);
memset(xp + size, 0, len - size);
UNIONFSDEBUG("unionfs_mount: from %s, on %s\n",
mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
return (0);
}
/*
* Free reference to unionfs layer
*/
int
unionfs_unmount(struct mount *mp, int mntflags)
{
struct unionfs_mount *ump;
int error;
int freeing;
int flags;
UNIONFSDEBUG("unionfs_unmount: mp = %p\n", (void *)mp);
ump = MOUNTTOUNIONFSMOUNT(mp);
flags = 0;
if (mntflags & MNT_FORCE)
flags |= FORCECLOSE;
/* vflush (no need to call vrele) */
for (freeing = 0; (error = vflush(mp, NULL, flags)) != 0;) {
struct vnode *vp;
int n;
/* count #vnodes held on mount list */
n = 0;
TAILQ_FOREACH(vp, &mp->mnt_vnodelist, v_mntvnodes)
n++;
/* if this is unchanged then stop */
if (n == freeing)
break;
/* otherwise try once more time */
freeing = n;
}
if (error)
return (error);
free(ump, M_UNIONFSMNT);
mp->mnt_data = NULL;
return (0);
}
int
unionfs_root(struct mount *mp, struct vnode **vpp)
{
struct unionfs_mount *ump;
struct vnode *vp;
ump = MOUNTTOUNIONFSMOUNT(mp);
vp = ump->um_rootvp;
UNIONFSDEBUG("unionfs_root: rootvp=%p locked=%x\n",
vp, VOP_ISLOCKED(vp));
vref(vp);
vn_lock(vp, LK_EXCLUSIVE);
*vpp = vp;
return (0);
}
int
unionfs_quotactl(struct mount *mp, struct quotactl_args *args)
{
struct unionfs_mount *ump;
ump = MOUNTTOUNIONFSMOUNT(mp);
/*
* Writing is always performed to upper vnode.
*/
return (VFS_QUOTACTL(ump->um_uppervp->v_mount, args));
}
int
unionfs_statvfs(struct mount *mp, struct statvfs *sbp)
{
struct unionfs_mount *ump;
int error;
uint64_t lbsize;
struct statvfs *sbuf = malloc(sizeof(*sbuf), M_TEMP, M_WAITOK | M_ZERO);
ump = MOUNTTOUNIONFSMOUNT(mp);
UNIONFSDEBUG("unionfs_statvfs(mp = %p, lvp = %p, uvp = %p)\n",
(void *)mp, (void *)ump->um_lowervp, (void *)ump->um_uppervp);
error = VFS_STATVFS(ump->um_lowervp->v_mount, sbuf);
if (error)
goto done;
/* now copy across the "interesting" information and fake the rest */
sbp->f_blocks = sbuf->f_blocks;
sbp->f_files = sbuf->f_files;
lbsize = sbuf->f_bsize;
error = VFS_STATVFS(ump->um_uppervp->v_mount, sbuf);
if (error)
goto done;
/*
* The FS type etc is copy from upper vfs.
* (write able vfs have priority)
*/
sbp->f_flag = sbuf->f_flag;
sbp->f_bsize = sbuf->f_bsize;
sbp->f_iosize = sbuf->f_iosize;
if (sbuf->f_bsize != lbsize)
sbp->f_blocks = ((off_t)sbp->f_blocks * lbsize) / sbuf->f_bsize;
sbp->f_blocks += sbuf->f_blocks;
sbp->f_bfree = sbuf->f_bfree;
sbp->f_bavail = sbuf->f_bavail;
sbp->f_files += sbuf->f_files;
sbp->f_ffree = sbuf->f_ffree;
done:
free(sbuf, M_TEMP);
return (error);
}
int
unionfs_sync(struct mount *mp, int waitfor, kauth_cred_t cred)
{
/* nothing to do */
return (0);
}
int
unionfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp)
{
return (EOPNOTSUPP);
}
int
unionfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp)
{
return (EOPNOTSUPP);
}
int
unionfs_extattrctl(struct mount *mp, int cmd, struct vnode *filename_vp,
int namespace, const char *attrname)
{
struct unionfs_mount *ump;
struct unionfs_node *unp;
ump = MOUNTTOUNIONFSMOUNT(mp);
unp = VTOUNIONFS(filename_vp);
if (unp->un_uppervp != NULLVP) {
return (VFS_EXTATTRCTL(ump->um_uppervp->v_mount, cmd,
unp->un_uppervp, namespace, attrname));
} else {
return (VFS_EXTATTRCTL(ump->um_lowervp->v_mount, cmd,
unp->un_lowervp, namespace, attrname));
}
}
/*
* Initialize
*/
void
unionfs_init(void)
{
UNIONFSDEBUG("unionfs_init\n"); /* printed during system boot */
}
static int
unionfs_renamelock_enter(struct mount *mp)
{
struct unionfs_mount *um = MOUNTTOUNIONFSMOUNT(mp);
/* Lock just the upper fs, where the action happens. */
return VFS_RENAMELOCK_ENTER(um->um_uppervp->v_mount);
}
static void
unionfs_renamelock_exit(struct mount *mp)
{
struct unionfs_mount *um = MOUNTTOUNIONFSMOUNT(mp);
VFS_RENAMELOCK_EXIT(um->um_uppervp->v_mount);
}
int
unionfs_start(struct mount *mp, int flags)
{
return (0);
}
void
unionfs_done(void)
{
/* Make sure to unset the readdir hook. */
vn_union_readdir_hook = NULL;
}
extern const struct vnodeopv_desc unionfs_vnodeop_opv_desc;
const struct vnodeopv_desc * const unionfs_vnodeopv_descs[] = {
&unionfs_vnodeop_opv_desc,
NULL,
};
struct vfsops unionfs_vfsops = {
MOUNT_UNION,
sizeof (struct unionfs_args),
unionfs_mount,
unionfs_start,
unionfs_unmount,
unionfs_root,
(void *)eopnotsupp, /* vfs_quotactl */
unionfs_statvfs,
unionfs_sync,
unionfs_vget,
(void *)eopnotsupp, /* vfs_fhtovp */
(void *)eopnotsupp, /* vfs_vptofh */
unionfs_init,
NULL, /* vfs_reinit */
unionfs_done,
NULL, /* vfs_mountroot */
(int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp,
vfs_stdextattrctl,
(void *)eopnotsupp, /* vfs_suspendctl */
unionfs_renamelock_enter,
unionfs_renamelock_exit,
(void *)eopnotsupp,
unionfs_vnodeopv_descs,
0, /* vfs_refcount */
{ NULL, NULL },
};
static int
unionfs_modcmd(modcmd_t cmd, void *arg)
{
int error;
switch (cmd) {
case MODULE_CMD_INIT:
error = vfs_attach(&unionfs_vfsops);
if (error != 0)
break;
sysctl_createv(&unionfs_sysctl_log, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "vfs", NULL,
NULL, 0, NULL, 0,
CTL_VFS, CTL_EOL);
sysctl_createv(&unionfs_sysctl_log, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "union",
SYSCTL_DESCR("Union file system"),
NULL, 0, NULL, 0,
CTL_VFS, 15, CTL_EOL);
/*
* XXX the "15" above could be dynamic, thereby eliminating
* one more instance of the "number to vfs" mapping problem,
* but "15" is the order as taken from sys/mount.h
*/
break;
case MODULE_CMD_FINI:
error = vfs_detach(&unionfs_vfsops);
if (error != 0)
break;
sysctl_teardown(&unionfs_sysctl_log);
break;
default:
error = ENOTTY;
break;
}
return (error);
}