507 lines
13 KiB
C
507 lines
13 KiB
C
/*
|
|
* Copyright (c) 1994, 1995 The Regents of the University of California.
|
|
* Copyright (c) 1994, 1995 Jan-Simon Pendry.
|
|
* 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. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 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
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
/*
|
|
* Union Layer
|
|
*/
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/vnode.h>
|
|
#include <sys/mount.h>
|
|
#include <sys/namei.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/filedesc.h>
|
|
#include <miscfs/union/union.h>
|
|
|
|
static MALLOC_DEFINE(M_UNIONFSMNT, "UNION mount", "UNION mount structure");
|
|
|
|
extern int union_init __P((struct vfsconf *));
|
|
static int union_mount __P((struct mount *mp, char *path, caddr_t data,
|
|
struct nameidata *ndp, struct proc *p));
|
|
static int union_root __P((struct mount *mp, struct vnode **vpp));
|
|
static int union_statfs __P((struct mount *mp, struct statfs *sbp,
|
|
struct proc *p));
|
|
static int union_unmount __P((struct mount *mp, int mntflags,
|
|
struct proc *p));
|
|
|
|
/*
|
|
* Mount union filesystem
|
|
*/
|
|
static int
|
|
union_mount(mp, path, data, ndp, p)
|
|
struct mount *mp;
|
|
char *path;
|
|
caddr_t data;
|
|
struct nameidata *ndp;
|
|
struct proc *p;
|
|
{
|
|
int error = 0;
|
|
struct union_args args;
|
|
struct vnode *lowerrootvp = NULLVP;
|
|
struct vnode *upperrootvp = NULLVP;
|
|
struct union_mount *um = 0;
|
|
struct ucred *cred = 0;
|
|
char *cp = 0;
|
|
int len;
|
|
u_int size;
|
|
|
|
UDEBUG(("union_mount(mp = %p)\n", (void *)mp));
|
|
|
|
/*
|
|
* Disable clustered write, otherwise system becomes unstable.
|
|
*/
|
|
mp->mnt_flag |= MNT_NOCLUSTERW;
|
|
|
|
/*
|
|
* Update is a no-op
|
|
*/
|
|
if (mp->mnt_flag & MNT_UPDATE) {
|
|
/*
|
|
* Need to provide.
|
|
* 1. a way to convert between rdonly and rdwr mounts.
|
|
* 2. support for nfs exports.
|
|
*/
|
|
error = EOPNOTSUPP;
|
|
goto bad;
|
|
}
|
|
|
|
/*
|
|
* Get argument
|
|
*/
|
|
error = copyin(data, (caddr_t)&args, sizeof(struct union_args));
|
|
if (error)
|
|
goto bad;
|
|
|
|
/*
|
|
* Obtain lower vnode. Vnode is stored in mp->mnt_vnodecovered.
|
|
* We need to reference it but not lock it.
|
|
*/
|
|
|
|
lowerrootvp = mp->mnt_vnodecovered;
|
|
VREF(lowerrootvp);
|
|
|
|
#if 0
|
|
/*
|
|
* Unlock lower node to avoid deadlock.
|
|
*/
|
|
if (lowerrootvp->v_op == union_vnodeop_p)
|
|
VOP_UNLOCK(lowerrootvp, 0, p);
|
|
#endif
|
|
|
|
/*
|
|
* Obtain upper vnode by calling namei() on the path. The
|
|
* upperrootvp will be turned referenced but not locked.
|
|
*/
|
|
NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT,
|
|
UIO_USERSPACE, args.target, p);
|
|
|
|
error = namei(ndp);
|
|
|
|
#if 0
|
|
if (lowerrootvp->v_op == union_vnodeop_p)
|
|
vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY, p);
|
|
#endif
|
|
if (error)
|
|
goto bad;
|
|
|
|
NDFREE(ndp, NDF_ONLY_PNBUF);
|
|
upperrootvp = ndp->ni_vp;
|
|
vrele(ndp->ni_dvp);
|
|
ndp->ni_dvp = NULL;
|
|
|
|
UDEBUG(("mount_root UPPERVP %p locked = %d\n", upperrootvp,
|
|
VOP_ISLOCKED(upperrootvp, NULL)));
|
|
|
|
/*
|
|
* Check multi union mount to avoid `lock myself again' panic.
|
|
* Also require that it be a directory.
|
|
*/
|
|
if (upperrootvp == VTOUNION(lowerrootvp)->un_uppervp) {
|
|
#ifdef DIAGNOSTIC
|
|
printf("union_mount: multi union mount?\n");
|
|
#endif
|
|
error = EDEADLK;
|
|
goto bad;
|
|
}
|
|
|
|
if (upperrootvp->v_type != VDIR) {
|
|
error = EINVAL;
|
|
goto bad;
|
|
}
|
|
|
|
/*
|
|
* Allocate our union_mount structure and populate the fields.
|
|
* The vnode references are stored in the union_mount as held,
|
|
* unlocked references. Depending on the _BELOW flag, the
|
|
* filesystems are viewed in a different order. In effect this
|
|
* is the same as providing a mount-under option to the mount
|
|
* syscall.
|
|
*/
|
|
|
|
um = (struct union_mount *) malloc(sizeof(struct union_mount),
|
|
M_UNIONFSMNT, M_WAITOK | M_ZERO);
|
|
|
|
um->um_op = args.mntflags & UNMNT_OPMASK;
|
|
|
|
switch (um->um_op) {
|
|
case UNMNT_ABOVE:
|
|
um->um_lowervp = lowerrootvp;
|
|
um->um_uppervp = upperrootvp;
|
|
upperrootvp = NULL;
|
|
lowerrootvp = NULL;
|
|
break;
|
|
|
|
case UNMNT_BELOW:
|
|
um->um_lowervp = upperrootvp;
|
|
um->um_uppervp = lowerrootvp;
|
|
upperrootvp = NULL;
|
|
lowerrootvp = NULL;
|
|
break;
|
|
|
|
case UNMNT_REPLACE:
|
|
vrele(lowerrootvp);
|
|
lowerrootvp = NULL;
|
|
um->um_uppervp = upperrootvp;
|
|
um->um_lowervp = lowerrootvp;
|
|
upperrootvp = NULL;
|
|
break;
|
|
|
|
default:
|
|
error = EINVAL;
|
|
goto bad;
|
|
}
|
|
|
|
/*
|
|
* Unless the mount is readonly, ensure that the top layer
|
|
* supports whiteout operations
|
|
*/
|
|
if ((mp->mnt_flag & MNT_RDONLY) == 0) {
|
|
error = VOP_WHITEOUT(um->um_uppervp, NULL, LOOKUP);
|
|
if (error)
|
|
goto bad;
|
|
}
|
|
|
|
um->um_cred = p->p_ucred;
|
|
crhold(um->um_cred);
|
|
um->um_cmode = UN_DIRMODE &~ p->p_fd->fd_cmask;
|
|
|
|
/*
|
|
* Depending on what you think the MNT_LOCAL flag might mean,
|
|
* you may want the && to be || on the conditional below.
|
|
* At the moment it has been defined that the filesystem is
|
|
* only local if it is all local, ie the MNT_LOCAL flag implies
|
|
* that the entire namespace is local. If you think the MNT_LOCAL
|
|
* flag implies that some of the files might be stored locally
|
|
* then you will want to change the conditional.
|
|
*/
|
|
if (um->um_op == UNMNT_ABOVE) {
|
|
if (((um->um_lowervp == NULLVP) ||
|
|
(um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) &&
|
|
(um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
|
|
mp->mnt_flag |= MNT_LOCAL;
|
|
}
|
|
|
|
/*
|
|
* Copy in the upper layer's RDONLY flag. This is for the benefit
|
|
* of lookup() which explicitly checks the flag, rather than asking
|
|
* the filesystem for its own opinion. This means, that an update
|
|
* mount of the underlying filesystem to go from rdonly to rdwr
|
|
* will leave the unioned view as read-only.
|
|
*/
|
|
mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY);
|
|
|
|
mp->mnt_data = (qaddr_t) um;
|
|
vfs_getnewfsid(mp);
|
|
|
|
(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
|
|
bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
|
|
|
|
switch (um->um_op) {
|
|
case UNMNT_ABOVE:
|
|
cp = "<above>:";
|
|
break;
|
|
case UNMNT_BELOW:
|
|
cp = "<below>:";
|
|
break;
|
|
case UNMNT_REPLACE:
|
|
cp = "";
|
|
break;
|
|
}
|
|
len = strlen(cp);
|
|
bcopy(cp, mp->mnt_stat.f_mntfromname, len);
|
|
|
|
cp = mp->mnt_stat.f_mntfromname + len;
|
|
len = MNAMELEN - len;
|
|
|
|
(void) copyinstr(args.target, cp, len - 1, &size);
|
|
bzero(cp + size, len - size);
|
|
|
|
(void)union_statfs(mp, &mp->mnt_stat, p);
|
|
|
|
UDEBUG(("union_mount: from %s, on %s\n",
|
|
mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname));
|
|
return (0);
|
|
|
|
bad:
|
|
if (um) {
|
|
if (um->um_uppervp)
|
|
vrele(um->um_uppervp);
|
|
if (um->um_lowervp)
|
|
vrele(um->um_lowervp);
|
|
/* XXX other fields */
|
|
free(um, M_UNIONFSMNT);
|
|
}
|
|
if (cred)
|
|
crfree(cred);
|
|
if (upperrootvp)
|
|
vrele(upperrootvp);
|
|
if (lowerrootvp)
|
|
vrele(lowerrootvp);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Free reference to union layer
|
|
*/
|
|
static int
|
|
union_unmount(mp, mntflags, p)
|
|
struct mount *mp;
|
|
int mntflags;
|
|
struct proc *p;
|
|
{
|
|
struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
|
|
struct vnode *um_rootvp;
|
|
int error;
|
|
int freeing;
|
|
int flags = 0;
|
|
|
|
UDEBUG(("union_unmount(mp = %p)\n", (void *)mp));
|
|
|
|
if (mntflags & MNT_FORCE)
|
|
flags |= FORCECLOSE;
|
|
|
|
if ((error = union_root(mp, &um_rootvp)) != 0)
|
|
return (error);
|
|
|
|
/*
|
|
* Keep flushing vnodes from the mount list.
|
|
* This is needed because of the un_pvp held
|
|
* reference to the parent vnode.
|
|
* If more vnodes have been freed on a given pass,
|
|
* the try again. The loop will iterate at most
|
|
* (d) times, where (d) is the maximum tree depth
|
|
* in the filesystem.
|
|
*/
|
|
for (freeing = 0; vflush(mp, um_rootvp, flags) != 0;) {
|
|
struct vnode *vp;
|
|
int n;
|
|
|
|
/* count #vnodes held on mount list */
|
|
for (n = 0, vp = mp->mnt_vnodelist.lh_first;
|
|
vp != NULLVP;
|
|
vp = vp->v_mntvnodes.le_next)
|
|
n++;
|
|
|
|
/* if this is unchanged then stop */
|
|
if (n == freeing)
|
|
break;
|
|
|
|
/* otherwise try once more time */
|
|
freeing = n;
|
|
}
|
|
|
|
/* At this point the root vnode should have a single reference */
|
|
if (um_rootvp->v_usecount > 1) {
|
|
vput(um_rootvp);
|
|
return (EBUSY);
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
vprint("union root", um_rootvp);
|
|
#endif
|
|
/*
|
|
* Discard references to upper and lower target vnodes.
|
|
*/
|
|
if (um->um_lowervp)
|
|
vrele(um->um_lowervp);
|
|
vrele(um->um_uppervp);
|
|
crfree(um->um_cred);
|
|
/*
|
|
* Release reference on underlying root vnode
|
|
*/
|
|
vput(um_rootvp);
|
|
/*
|
|
* And blow it away for future re-use
|
|
*/
|
|
vgone(um_rootvp);
|
|
/*
|
|
* Finally, throw away the union_mount structure
|
|
*/
|
|
free(mp->mnt_data, M_UNIONFSMNT); /* XXX */
|
|
mp->mnt_data = 0;
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
union_root(mp, vpp)
|
|
struct mount *mp;
|
|
struct vnode **vpp;
|
|
{
|
|
struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
|
|
int error;
|
|
|
|
/*
|
|
* Supply an unlocked reference to um_uppervp and to um_lowervp. It
|
|
* is possible for um_uppervp to be locked without the associated
|
|
* root union_node being locked. We let union_allocvp() deal with
|
|
* it.
|
|
*/
|
|
UDEBUG(("union_root UPPERVP %p locked = %d\n", um->um_uppervp,
|
|
VOP_ISLOCKED(um->um_uppervp, NULL)));
|
|
|
|
VREF(um->um_uppervp);
|
|
if (um->um_lowervp)
|
|
VREF(um->um_lowervp);
|
|
|
|
error = union_allocvp(vpp, mp, NULLVP, NULLVP, NULL,
|
|
um->um_uppervp, um->um_lowervp, 1);
|
|
UDEBUG(("error %d\n", error));
|
|
UDEBUG(("union_root2 UPPERVP %p locked = %d\n", um->um_uppervp,
|
|
VOP_ISLOCKED(um->um_uppervp, NULL)));
|
|
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
union_statfs(mp, sbp, p)
|
|
struct mount *mp;
|
|
struct statfs *sbp;
|
|
struct proc *p;
|
|
{
|
|
int error;
|
|
struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
|
|
struct statfs mstat;
|
|
int lbsize;
|
|
|
|
UDEBUG(("union_statfs(mp = %p, lvp = %p, uvp = %p)\n",
|
|
(void *)mp, (void *)um->um_lowervp, (void *)um->um_uppervp));
|
|
|
|
bzero(&mstat, sizeof(mstat));
|
|
|
|
if (um->um_lowervp) {
|
|
error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, p);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
|
|
/* now copy across the "interesting" information and fake the rest */
|
|
#if 0
|
|
sbp->f_type = mstat.f_type;
|
|
sbp->f_flags = mstat.f_flags;
|
|
sbp->f_bsize = mstat.f_bsize;
|
|
sbp->f_iosize = mstat.f_iosize;
|
|
#endif
|
|
lbsize = mstat.f_bsize;
|
|
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;
|
|
|
|
error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, p);
|
|
if (error)
|
|
return (error);
|
|
|
|
sbp->f_flags = mstat.f_flags;
|
|
sbp->f_bsize = mstat.f_bsize;
|
|
sbp->f_iosize = mstat.f_iosize;
|
|
|
|
/*
|
|
* if the lower and upper blocksizes differ, then frig the
|
|
* block counts so that the sizes reported by df make some
|
|
* kind of sense. none of this makes sense though.
|
|
*/
|
|
|
|
if (mstat.f_bsize != lbsize)
|
|
sbp->f_blocks = ((off_t) sbp->f_blocks * lbsize) / mstat.f_bsize;
|
|
|
|
/*
|
|
* The "total" fields count total resources in all layers,
|
|
* the "free" fields count only those resources which are
|
|
* free in the upper layer (since only the upper layer
|
|
* is writeable).
|
|
*/
|
|
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) {
|
|
sbp->f_type = mp->mnt_vfc->vfc_typenum;
|
|
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 struct vfsops union_vfsops = {
|
|
union_mount,
|
|
vfs_stdstart, /* underlying start already done */
|
|
union_unmount,
|
|
union_root,
|
|
vfs_stdquotactl,
|
|
union_statfs,
|
|
vfs_stdsync, /* XXX assumes no cached data on union level */
|
|
vfs_stdvget,
|
|
vfs_stdfhtovp,
|
|
vfs_stdcheckexp,
|
|
vfs_stdvptofh,
|
|
union_init,
|
|
vfs_stduninit,
|
|
vfs_stdextattrctl,
|
|
};
|
|
|
|
VFS_SET(union_vfsops, union, VFCF_LOOPBACK);
|