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freebsd-nq/sys/miscfs/union/union_vnops.c
Mike Smith 7be2d30077 In the words of the submitter: 
---------
Make callers of namei() responsible for releasing references or locks
instead of having the underlying filesystems do it.  This eliminates
redundancy in all terminal filesystems and makes it possible for stacked
transport layers such as umapfs or nullfs to operate correctly.

Quality testing was done with testvn, and lat_fs from the lmbench suite.

Some NFS client testing courtesy of Patrik Kudo.

vop_mknod and vop_symlink still release the returned vpp.  vop_rename
still releases 4 vnode arguments before it returns.  These remaining cases
will be corrected in the next set of patches.
---------

Submitted by:	Michael Hancock <michaelh@cet.co.jp>
1998-05-07 04:58:58 +00:00

1800 lines
42 KiB
C
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/*
* Copyright (c) 1992, 1993, 1994, 1995 Jan-Simon Pendry.
* Copyright (c) 1992, 1993, 1994, 1995
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed 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_vnops.c 8.32 (Berkeley) 6/23/95
* $Id: union_vnops.c,v 1.56 1998/03/17 08:47:50 kato Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/fcntl.h>
#include <sys/stat.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <sys/buf.h>
#include <sys/lock.h>
#include <miscfs/union/union.h>
#define FIXUP(un, p) { \
if (((un)->un_flags & UN_ULOCK) == 0) { \
union_fixup(un, p); \
} \
}
static int union_abortop __P((struct vop_abortop_args *ap));
static int union_access __P((struct vop_access_args *ap));
static int union_advlock __P((struct vop_advlock_args *ap));
static int union_bmap __P((struct vop_bmap_args *ap));
static int union_close __P((struct vop_close_args *ap));
static int union_create __P((struct vop_create_args *ap));
static void union_fixup __P((struct union_node *un, struct proc *p));
static int union_fsync __P((struct vop_fsync_args *ap));
static int union_getattr __P((struct vop_getattr_args *ap));
static int union_inactive __P((struct vop_inactive_args *ap));
static int union_ioctl __P((struct vop_ioctl_args *ap));
static int union_islocked __P((struct vop_islocked_args *ap));
static int union_lease __P((struct vop_lease_args *ap));
static int union_link __P((struct vop_link_args *ap));
static int union_lock __P((struct vop_lock_args *ap));
static int union_lookup __P((struct vop_lookup_args *ap));
static int union_lookup1 __P((struct vnode *udvp, struct vnode **dvpp,
struct vnode **vpp,
struct componentname *cnp));
static int union_mkdir __P((struct vop_mkdir_args *ap));
static int union_mknod __P((struct vop_mknod_args *ap));
static int union_mmap __P((struct vop_mmap_args *ap));
static int union_open __P((struct vop_open_args *ap));
static int union_pathconf __P((struct vop_pathconf_args *ap));
static int union_print __P((struct vop_print_args *ap));
static int union_read __P((struct vop_read_args *ap));
static int union_readdir __P((struct vop_readdir_args *ap));
static int union_readlink __P((struct vop_readlink_args *ap));
static int union_reclaim __P((struct vop_reclaim_args *ap));
static int union_remove __P((struct vop_remove_args *ap));
static int union_rename __P((struct vop_rename_args *ap));
static int union_revoke __P((struct vop_revoke_args *ap));
static int union_rmdir __P((struct vop_rmdir_args *ap));
static int union_poll __P((struct vop_poll_args *ap));
static int union_setattr __P((struct vop_setattr_args *ap));
static int union_strategy __P((struct vop_strategy_args *ap));
static int union_symlink __P((struct vop_symlink_args *ap));
static int union_unlock __P((struct vop_unlock_args *ap));
static int union_whiteout __P((struct vop_whiteout_args *ap));
static int union_write __P((struct vop_read_args *ap));
static void
union_fixup(un, p)
struct union_node *un;
struct proc *p;
{
vn_lock(un->un_uppervp, LK_EXCLUSIVE | LK_RETRY, p);
un->un_flags |= UN_ULOCK;
}
static int
union_lookup1(udvp, dvpp, vpp, cnp)
struct vnode *udvp;
struct vnode **dvpp;
struct vnode **vpp;
struct componentname *cnp;
{
int error;
struct proc *p = cnp->cn_proc;
struct vnode *tdvp;
struct vnode *dvp;
struct mount *mp;
dvp = *dvpp;
/*
* If stepping up the directory tree, check for going
* back across the mount point, in which case do what
* lookup would do by stepping back down the mount
* hierarchy.
*/
if (cnp->cn_flags & ISDOTDOT) {
while ((dvp != udvp) && (dvp->v_flag & VROOT)) {
/*
* Don't do the NOCROSSMOUNT check
* at this level. By definition,
* union fs deals with namespaces, not
* filesystems.
*/
tdvp = dvp;
*dvpp = dvp = dvp->v_mount->mnt_vnodecovered;
vput(tdvp);
VREF(dvp);
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p);
}
}
error = VOP_LOOKUP(dvp, &tdvp, cnp);
if (error)
return (error);
/*
* The parent directory will have been unlocked, unless lookup
* found the last component. In which case, re-lock the node
* here to allow it to be unlocked again (phew) in union_lookup.
*/
if (dvp != tdvp && !(cnp->cn_flags & ISLASTCN))
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p);
dvp = tdvp;
/*
* Lastly check if the current node is a mount point in
* which case walk up the mount hierarchy making sure not to
* bump into the root of the mount tree (ie. dvp != udvp).
*/
while (dvp != udvp && (dvp->v_type == VDIR) &&
(mp = dvp->v_mountedhere)) {
if (vfs_busy(mp, 0, 0, p))
continue;
error = VFS_ROOT(mp, &tdvp);
vfs_unbusy(mp, p);
if (error) {
vput(dvp);
return (error);
}
vput(dvp);
dvp = tdvp;
}
*vpp = dvp;
return (0);
}
static int
union_lookup(ap)
struct vop_lookup_args /* {
struct vnodeop_desc *a_desc;
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
} */ *ap;
{
int error;
int uerror, lerror;
struct vnode *uppervp, *lowervp;
struct vnode *upperdvp, *lowerdvp;
struct vnode *dvp = ap->a_dvp;
struct union_node *dun = VTOUNION(dvp);
struct componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
int lockparent = cnp->cn_flags & LOCKPARENT;
struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount);
struct ucred *saved_cred;
int iswhiteout;
struct vattr va;
/*
* Disallow write attemps to the filesystem mounted read-only.
*/
if ((cnp->cn_flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
return (EROFS);
#ifdef notyet
if (cnp->cn_namelen == 3 &&
cnp->cn_nameptr[2] == '.' &&
cnp->cn_nameptr[1] == '.' &&
cnp->cn_nameptr[0] == '.') {
dvp = *ap->a_vpp = LOWERVP(ap->a_dvp);
if (dvp == NULLVP)
return (ENOENT);
VREF(dvp);
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p);
if (!lockparent || !(cnp->cn_flags & ISLASTCN))
VOP_UNLOCK(ap->a_dvp, 0, p);
return (0);
}
#endif
cnp->cn_flags |= LOCKPARENT;
upperdvp = dun->un_uppervp;
lowerdvp = dun->un_lowervp;
uppervp = NULLVP;
lowervp = NULLVP;
iswhiteout = 0;
if (cnp->cn_flags & ISDOTDOT) {
if (upperdvp != NULL)
VREF(upperdvp);
if (lowerdvp != NULL)
VREF(lowerdvp);
}
/*
* do the lookup in the upper level.
* if that level comsumes additional pathnames,
* then assume that something special is going
* on and just return that vnode.
*/
if (upperdvp != NULLVP) {
FIXUP(dun, p);
/*
* If we're doing `..' in the underlying filesystem,
* we must drop our lock on the union node before
* going up the tree in the lower file system--if we block
* on the lowervp lock, and that's held by someone else
* coming down the tree and who's waiting for our lock,
* we would be hosed.
*/
if (cnp->cn_flags & ISDOTDOT) {
/* retain lock on underlying VP: */
dun->un_flags |= UN_KLOCK;
VOP_UNLOCK(dvp, 0, p);
}
uerror = union_lookup1(um->um_uppervp, &upperdvp,
&uppervp, cnp);
/*
* Disallow write attemps to the filesystem mounted read-only.
*/
if (uerror == EJUSTRETURN && (cnp->cn_flags & ISLASTCN) &&
(dvp->v_mount->mnt_flag & MNT_RDONLY) &&
(cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME)) {
if (!lockparent)
cnp->cn_flags &= ~LOCKPARENT;
return (EROFS);
}
if (cnp->cn_flags & ISDOTDOT) {
if (dun->un_uppervp == upperdvp) {
/*
* We got the underlying bugger back locked...
* now take back the union node lock. Since we
* hold the uppervp lock, we can diddle union
* locking flags at will. :)
*/
dun->un_flags |= UN_ULOCK;
}
/*
* If upperdvp got swapped out, it means we did
* some mount point magic, and we do not have
* dun->un_uppervp locked currently--so we get it
* locked here (don't set the UN_ULOCK flag).
*/
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p);
}
/*if (uppervp == upperdvp)
dun->un_flags |= UN_KLOCK;*/
if (cnp->cn_consume != 0) {
*ap->a_vpp = uppervp;
if (!lockparent)
cnp->cn_flags &= ~LOCKPARENT;
error = uerror;
goto out;
}
if (uerror == ENOENT || uerror == EJUSTRETURN) {
if (cnp->cn_flags & ISWHITEOUT) {
iswhiteout = 1;
} else if (lowerdvp != NULLVP) {
lerror = VOP_GETATTR(upperdvp, &va,
cnp->cn_cred, cnp->cn_proc);
if (lerror == 0 && (va.va_flags & OPAQUE))
iswhiteout = 1;
}
}
} else {
uerror = ENOENT;
}
/*
* in a similar way to the upper layer, do the lookup
* in the lower layer. this time, if there is some
* component magic going on, then vput whatever we got
* back from the upper layer and return the lower vnode
* instead.
*/
if (lowerdvp != NULLVP && !iswhiteout) {
int nameiop;
vn_lock(lowerdvp, LK_EXCLUSIVE | LK_RETRY, p);
/*
* Only do a LOOKUP on the bottom node, since
* we won't be making changes to it anyway.
*/
nameiop = cnp->cn_nameiop;
cnp->cn_nameiop = LOOKUP;
if (um->um_op == UNMNT_BELOW) {
saved_cred = cnp->cn_cred;
cnp->cn_cred = um->um_cred;
}
/*
* We shouldn't have to worry about locking interactions
* between the lower layer and our union layer (w.r.t.
* `..' processing) because we don't futz with lowervp
* locks in the union-node instantiation code path.
*/
lerror = union_lookup1(um->um_lowervp, &lowerdvp,
&lowervp, cnp);
if (um->um_op == UNMNT_BELOW)
cnp->cn_cred = saved_cred;
cnp->cn_nameiop = nameiop;
if (lowervp != lowerdvp)
VOP_UNLOCK(lowerdvp, 0, p);
if (cnp->cn_consume != 0 || lerror == EACCES) {
if (lerror == EACCES)
lowervp = NULLVP;
if (uppervp != NULLVP) {
if (uppervp == upperdvp)
vrele(uppervp);
else
vput(uppervp);
uppervp = NULLVP;
}
*ap->a_vpp = lowervp;
if (!lockparent)
cnp->cn_flags &= ~LOCKPARENT;
error = lerror;
goto out;
}
} else {
lerror = ENOENT;
if ((cnp->cn_flags & ISDOTDOT) && dun->un_pvp != NULLVP) {
lowervp = LOWERVP(dun->un_pvp);
if (lowervp != NULLVP) {
VREF(lowervp);
vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY, p);
lerror = 0;
}
}
}
if (!lockparent)
cnp->cn_flags &= ~LOCKPARENT;
/*
* at this point, we have uerror and lerror indicating
* possible errors with the lookups in the upper and lower
* layers. additionally, uppervp and lowervp are (locked)
* references to existing vnodes in the upper and lower layers.
*
* there are now three cases to consider.
* 1. if both layers returned an error, then return whatever
* error the upper layer generated.
*
* 2. if the top layer failed and the bottom layer succeeded
* then two subcases occur.
* a. the bottom vnode is not a directory, in which
* case just return a new union vnode referencing
* an empty top layer and the existing bottom layer.
* b. the bottom vnode is a directory, in which case
* create a new directory in the top-level and
* continue as in case 3.
*
* 3. if the top layer succeeded then return a new union
* vnode referencing whatever the new top layer and
* whatever the bottom layer returned.
*/
*ap->a_vpp = NULLVP;
/* case 1. */
if ((uerror != 0) && (lerror != 0)) {
error = uerror;
goto out;
}
/* case 2. */
if (uerror != 0 /* && (lerror == 0) */ ) {
if (lowervp->v_type == VDIR) { /* case 2b. */
dun->un_flags &= ~UN_ULOCK;
VOP_UNLOCK(upperdvp, 0, p);
uerror = union_mkshadow(um, upperdvp, cnp, &uppervp);
vn_lock(upperdvp, LK_EXCLUSIVE | LK_RETRY, p);
dun->un_flags |= UN_ULOCK;
if (uerror) {
if (lowervp != NULLVP) {
vput(lowervp);
lowervp = NULLVP;
}
error = uerror;
goto out;
}
}
}
if (lowervp != NULLVP)
VOP_UNLOCK(lowervp, 0, p);
error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp,
uppervp, lowervp, 1);
if (error) {
if (uppervp != NULLVP)
vput(uppervp);
if (lowervp != NULLVP)
vrele(lowervp);
} else {
if (*ap->a_vpp != dvp)
if (!lockparent || !(cnp->cn_flags & ISLASTCN))
VOP_UNLOCK(dvp, 0, p);
#ifdef DIAGNOSTIC
if (cnp->cn_namelen == 1 &&
cnp->cn_nameptr[0] == '.' &&
*ap->a_vpp != dvp) {
panic("union_lookup returning . (%p) not same as startdir (%p)",
ap->a_vpp, dvp);
}
#endif
}
out:
if (cnp->cn_flags & ISDOTDOT) {
if (upperdvp != NULL)
vrele(upperdvp);
if (lowerdvp != NULL)
vrele(lowerdvp);
}
return (error);
}
static int
union_create(ap)
struct vop_create_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
struct vattr *a_vap;
} */ *ap;
{
struct union_node *dun = VTOUNION(ap->a_dvp);
struct vnode *dvp = dun->un_uppervp;
struct componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
if (dvp != NULLVP) {
struct vnode *vp;
struct mount *mp;
int error;
FIXUP(dun, p);
dun->un_flags |= UN_KLOCK;
VOP_UNLOCK(ap->a_dvp, 0, p);
error = VOP_CREATE(dvp, &vp, cnp, ap->a_vap);
if (error) {
dun->un_flags |= UN_ULOCK;
return (error);
}
mp = ap->a_dvp->v_mount;
VOP_UNLOCK(dvp, 0, p);
error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, cnp, vp,
NULLVP, 1);
if (error)
vput(vp);
vn_lock(ap->a_dvp, LK_EXCLUSIVE| LK_RETRY, p);
return (error);
}
return (EROFS);
}
static int
union_whiteout(ap)
struct vop_whiteout_args /* {
struct vnode *a_dvp;
struct componentname *a_cnp;
int a_flags;
} */ *ap;
{
struct union_node *un = VTOUNION(ap->a_dvp);
struct componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
if (un->un_uppervp == NULLVP)
return (EOPNOTSUPP);
FIXUP(un, p);
return (VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags));
}
static int
union_mknod(ap)
struct vop_mknod_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
struct vattr *a_vap;
} */ *ap;
{
struct union_node *dun = VTOUNION(ap->a_dvp);
struct vnode *dvp = dun->un_uppervp;
struct componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
if (dvp != NULLVP) {
struct vnode *vp;
struct mount *mp;
int error;
FIXUP(dun, p);
dun->un_flags |= UN_KLOCK;
VOP_UNLOCK(ap->a_dvp, 0, p);
error = VOP_MKNOD(dvp, &vp, cnp, ap->a_vap);
if (error) {
dun->un_flags |= UN_ULOCK;
return (error);
}
if (vp != NULLVP) {
mp = ap->a_dvp->v_mount;
VOP_UNLOCK(dvp, 0, p);
error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP,
cnp, vp, NULLVP, 1);
if (error)
vput(vp);
vn_lock(ap->a_dvp, LK_EXCLUSIVE| LK_RETRY, p);
} else {
dun->un_flags |= UN_ULOCK;
}
return (error);
}
return (EROFS);
}
static int
union_open(ap)
struct vop_open_args /* {
struct vnodeop_desc *a_desc;
struct vnode *a_vp;
int a_mode;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
struct union_node *un = VTOUNION(ap->a_vp);
struct vnode *tvp;
int mode = ap->a_mode;
struct ucred *cred = ap->a_cred;
struct proc *p = ap->a_p;
int error;
/*
* If there is an existing upper vp then simply open that.
*/
tvp = un->un_uppervp;
if (tvp == NULLVP) {
/*
* If the lower vnode is being opened for writing, then
* copy the file contents to the upper vnode and open that,
* otherwise can simply open the lower vnode.
*/
tvp = un->un_lowervp;
if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) {
error = union_copyup(un, (mode&O_TRUNC) == 0, cred, p);
if (error == 0)
error = VOP_OPEN(un->un_uppervp, mode, cred, p);
return (error);
}
/*
* Just open the lower vnode
*/
un->un_openl++;
vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY, p);
error = VOP_OPEN(tvp, mode, cred, p);
VOP_UNLOCK(tvp, 0, p);
return (error);
}
FIXUP(un, p);
error = VOP_OPEN(tvp, mode, cred, p);
return (error);
}
static int
union_close(ap)
struct vop_close_args /* {
struct vnode *a_vp;
int a_fflag;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
struct union_node *un = VTOUNION(ap->a_vp);
struct vnode *vp;
if ((vp = un->un_uppervp) == NULLVP) {
#ifdef UNION_DIAGNOSTIC
if (un->un_openl <= 0)
panic("union: un_openl cnt");
#endif
--un->un_openl;
vp = un->un_lowervp;
}
ap->a_vp = vp;
return (VCALL(vp, VOFFSET(vop_close), ap));
}
/*
* Check access permission on the union vnode.
* The access check being enforced is to check
* against both the underlying vnode, and any
* copied vnode. This ensures that no additional
* file permissions are given away simply because
* the user caused an implicit file copy.
*/
static int
union_access(ap)
struct vop_access_args /* {
struct vnodeop_desc *a_desc;
struct vnode *a_vp;
int a_mode;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
struct union_node *un = VTOUNION(ap->a_vp);
struct proc *p = ap->a_p;
int error = EACCES;
struct vnode *vp;
struct vnode *savedvp;
/*
* Disallow write attempts on filesystems mounted read-only.
*/
if (ap->a_mode & VWRITE && (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)) {
switch (ap->a_vp->v_type) {
case VREG: case VDIR: case VLNK:
return (EROFS);
}
}
if ((vp = un->un_uppervp) != NULLVP) {
FIXUP(un, p);
ap->a_vp = vp;
return (VCALL(vp, VOFFSET(vop_access), ap));
}
if ((vp = un->un_lowervp) != NULLVP) {
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
savedvp = ap->a_vp;
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_access), ap);
if (error == 0) {
struct union_mount *um = MOUNTTOUNIONMOUNT(savedvp->v_mount);
if (um->um_op == UNMNT_BELOW) {
ap->a_cred = um->um_cred;
error = VCALL(vp, VOFFSET(vop_access), ap);
}
}
VOP_UNLOCK(vp, 0, p);
if (error)
return (error);
}
return (error);
}
/*
* We handle getattr only to change the fsid and
* track object sizes
*/
static int
union_getattr(ap)
struct vop_getattr_args /* {
struct vnode *a_vp;
struct vattr *a_vap;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
int error;
struct union_node *un = VTOUNION(ap->a_vp);
struct vnode *vp = un->un_uppervp;
struct proc *p = ap->a_p;
struct vattr *vap;
struct vattr va;
/*
* Some programs walk the filesystem hierarchy by counting
* links to directories to avoid stat'ing all the time.
* This means the link count on directories needs to be "correct".
* The only way to do that is to call getattr on both layers
* and fix up the link count. The link count will not necessarily
* be accurate but will be large enough to defeat the tree walkers.
*/
vap = ap->a_vap;
vp = un->un_uppervp;
if (vp != NULLVP) {
/*
* It's not clear whether VOP_GETATTR is to be
* called with the vnode locked or not. stat() calls
* it with (vp) locked, and fstat calls it with
* (vp) unlocked.
* In the mean time, compensate here by checking
* the union_node's lock flag.
*/
if (un->un_flags & UN_LOCKED)
FIXUP(un, p);
error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p);
if (error)
return (error);
union_newsize(ap->a_vp, vap->va_size, VNOVAL);
}
if (vp == NULLVP) {
vp = un->un_lowervp;
} else if (vp->v_type == VDIR && un->un_lowervp != NULLVP) {
vp = un->un_lowervp;
vap = &va;
} else {
vp = NULLVP;
}
if (vp != NULLVP) {
error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p);
if (error)
return (error);
union_newsize(ap->a_vp, VNOVAL, vap->va_size);
}
if ((vap != ap->a_vap) && (vap->va_type == VDIR))
ap->a_vap->va_nlink += vap->va_nlink;
ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
return (0);
}
static int
union_setattr(ap)
struct vop_setattr_args /* {
struct vnode *a_vp;
struct vattr *a_vap;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
struct union_node *un = VTOUNION(ap->a_vp);
struct proc *p = ap->a_p;
struct vattr *vap = ap->a_vap;
int error;
/*
* Disallow write attempts on filesystems mounted read-only.
*/
if ((ap->a_vp->v_mount->mnt_flag & MNT_RDONLY) &&
(vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL))
return (EROFS);
/*
* Handle case of truncating lower object to zero size,
* by creating a zero length upper object. This is to
* handle the case of open with O_TRUNC and O_CREAT.
*/
if ((un->un_uppervp == NULLVP) &&
/* assert(un->un_lowervp != NULLVP) */
(un->un_lowervp->v_type == VREG)) {
error = union_copyup(un, (ap->a_vap->va_size != 0),
ap->a_cred, ap->a_p);
if (error)
return (error);
}
/*
* Try to set attributes in upper layer,
* otherwise return read-only filesystem error.
*/
if (un->un_uppervp != NULLVP) {
FIXUP(un, p);
error = VOP_SETATTR(un->un_uppervp, ap->a_vap,
ap->a_cred, ap->a_p);
if ((error == 0) && (ap->a_vap->va_size != VNOVAL))
union_newsize(ap->a_vp, ap->a_vap->va_size, VNOVAL);
} else {
error = EROFS;
}
return (error);
}
static int
union_read(ap)
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
int error;
struct proc *p = ap->a_uio->uio_procp;
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
else
FIXUP(VTOUNION(ap->a_vp), p);
error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);
if (dolock)
VOP_UNLOCK(vp, 0, p);
/*
* XXX
* perhaps the size of the underlying object has changed under
* our feet. take advantage of the offset information present
* in the uio structure.
*/
if (error == 0) {
struct union_node *un = VTOUNION(ap->a_vp);
off_t cur = ap->a_uio->uio_offset;
if (vp == un->un_uppervp) {
if (cur > un->un_uppersz)
union_newsize(ap->a_vp, cur, VNOVAL);
} else {
if (cur > un->un_lowersz)
union_newsize(ap->a_vp, VNOVAL, cur);
}
}
return (error);
}
static int
union_write(ap)
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
int error;
struct vnode *vp;
struct union_node *un = VTOUNION(ap->a_vp);
struct proc *p = ap->a_uio->uio_procp;
vp = UPPERVP(ap->a_vp);
if (vp == NULLVP)
panic("union: missing upper layer in write");
FIXUP(un, p);
error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);
/*
* the size of the underlying object may be changed by the
* write.
*/
if (error == 0) {
off_t cur = ap->a_uio->uio_offset;
if (cur > un->un_uppersz)
union_newsize(ap->a_vp, cur, VNOVAL);
}
return (error);
}
static int
union_lease(ap)
struct vop_lease_args /* {
struct vnode *a_vp;
struct proc *a_p;
struct ucred *a_cred;
int a_flag;
} */ *ap;
{
register struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_lease), ap));
}
static int
union_ioctl(ap)
struct vop_ioctl_args /* {
struct vnode *a_vp;
int a_command;
caddr_t a_data;
int a_fflag;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
register struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_ioctl), ap));
}
static int
union_poll(ap)
struct vop_poll_args /* {
struct vnode *a_vp;
int a_events;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
register struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_poll), ap));
}
static int
union_revoke(ap)
struct vop_revoke_args /* {
struct vnode *a_vp;
int a_flags;
struct proc *a_p;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
if (UPPERVP(vp))
VOP_REVOKE(UPPERVP(vp), ap->a_flags);
if (LOWERVP(vp))
VOP_REVOKE(LOWERVP(vp), ap->a_flags);
vgone(vp);
return (0);
}
static int
union_mmap(ap)
struct vop_mmap_args /* {
struct vnode *a_vp;
int a_fflags;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
register struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_mmap), ap));
}
static int
union_fsync(ap)
struct vop_fsync_args /* {
struct vnode *a_vp;
struct ucred *a_cred;
int a_waitfor;
struct proc *a_p;
} */ *ap;
{
int error = 0;
struct proc *p = ap->a_p;
struct vnode *targetvp = OTHERVP(ap->a_vp);
struct union_node *un;
if (targetvp != NULLVP) {
int dolock = (targetvp == LOWERVP(ap->a_vp));
un = VTOUNION(ap->a_vp);
if (dolock)
vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY, p);
else {
un = VTOUNION(ap->a_vp);
if ((un->un_flags & UN_ULOCK) == 0 &&
targetvp->v_data != NULL &&
((struct lock *)targetvp->v_data)->lk_lockholder
== curproc->p_pid &&
VOP_ISLOCKED(targetvp) != 0)
return 0; /* XXX */
FIXUP(un, p);
}
error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_waitfor, p);
if (dolock)
VOP_UNLOCK(targetvp, 0, p);
}
return (error);
}
static int
union_remove(ap)
struct vop_remove_args /* {
struct vnode *a_dvp;
struct vnode *a_vp;
struct componentname *a_cnp;
} */ *ap;
{
struct union_node *dun = VTOUNION(ap->a_dvp);
struct union_node *un = VTOUNION(ap->a_vp);
struct componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
int error;
if (dun->un_uppervp == NULLVP)
panic("union remove: null upper vnode");
if (un->un_uppervp != NULLVP) {
struct vnode *dvp = dun->un_uppervp;
struct vnode *vp = un->un_uppervp;
FIXUP(dun, p);
dun->un_flags |= UN_KLOCK;
VOP_UNLOCK(ap->a_dvp, 0, p);
FIXUP(un, p);
un->un_flags |= UN_KLOCK;
VOP_UNLOCK(ap->a_vp, 0, p);
if (union_dowhiteout(un, cnp->cn_cred, p))
cnp->cn_flags |= DOWHITEOUT;
error = VOP_REMOVE(dvp, vp, cnp);
#if 0
/* XXX */
if (!error)
union_removed_upper(un);
#endif
dun->un_flags |= UN_ULOCK;
un->un_flags |= UN_ULOCK;
} else {
FIXUP(dun, p);
error = union_mkwhiteout(
MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount),
dun->un_uppervp, ap->a_cnp, un->un_path);
}
return (error);
}
static int
union_link(ap)
struct vop_link_args /* {
struct vnode *a_tdvp;
struct vnode *a_vp;
struct componentname *a_cnp;
} */ *ap;
{
struct componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
struct union_node *dun = VTOUNION(ap->a_tdvp);
struct vnode *vp;
struct vnode *tdvp;
int error = 0;
if (ap->a_tdvp->v_op != ap->a_vp->v_op) {
vp = ap->a_vp;
} else {
struct union_node *tun = VTOUNION(ap->a_vp);
if (tun->un_uppervp == NULLVP) {
vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, p);
if (dun->un_uppervp == tun->un_dirvp) {
dun->un_flags &= ~UN_ULOCK;
VOP_UNLOCK(dun->un_uppervp, 0, p);
}
error = union_copyup(tun, 1, cnp->cn_cred, p);
if (dun->un_uppervp == tun->un_dirvp) {
vn_lock(dun->un_uppervp,
LK_EXCLUSIVE | LK_RETRY, p);
dun->un_flags |= UN_ULOCK;
}
VOP_UNLOCK(ap->a_vp, 0, p);
}
vp = tun->un_uppervp;
}
tdvp = dun->un_uppervp;
if (tdvp == NULLVP)
error = EROFS;
if (error)
return (error);
FIXUP(dun, p);
dun->un_flags |= UN_KLOCK;
VOP_UNLOCK(ap->a_tdvp, 0, p);
error = VOP_LINK(tdvp, vp, cnp);
dun->un_flags |= UN_ULOCK;
return (error);
}
static int
union_rename(ap)
struct vop_rename_args /* {
struct vnode *a_fdvp;
struct vnode *a_fvp;
struct componentname *a_fcnp;
struct vnode *a_tdvp;
struct vnode *a_tvp;
struct componentname *a_tcnp;
} */ *ap;
{
int error;
struct vnode *fdvp = ap->a_fdvp;
struct vnode *fvp = ap->a_fvp;
struct vnode *tdvp = ap->a_tdvp;
struct vnode *tvp = ap->a_tvp;
if (fdvp->v_op == union_vnodeop_p) { /* always true */
struct union_node *un = VTOUNION(fdvp);
if (un->un_uppervp == NULLVP) {
/*
* this should never happen in normal
* operation but might if there was
* a problem creating the top-level shadow
* directory.
*/
error = EXDEV;
goto bad;
}
fdvp = un->un_uppervp;
VREF(fdvp);
vrele(ap->a_fdvp);
}
if (fvp->v_op == union_vnodeop_p) { /* always true */
struct union_node *un = VTOUNION(fvp);
if (un->un_uppervp == NULLVP) {
/* XXX: should do a copyup */
error = EXDEV;
goto bad;
}
if (un->un_lowervp != NULLVP)
ap->a_fcnp->cn_flags |= DOWHITEOUT;
fvp = un->un_uppervp;
VREF(fvp);
vrele(ap->a_fvp);
}
if (tdvp->v_op == union_vnodeop_p) {
struct union_node *un = VTOUNION(tdvp);
if (un->un_uppervp == NULLVP) {
/*
* this should never happen in normal
* operation but might if there was
* a problem creating the top-level shadow
* directory.
*/
error = EXDEV;
goto bad;
}
tdvp = un->un_uppervp;
VREF(tdvp);
un->un_flags |= UN_KLOCK;
vput(ap->a_tdvp);
}
if (tvp != NULLVP && tvp->v_op == union_vnodeop_p) {
struct union_node *un = VTOUNION(tvp);
tvp = un->un_uppervp;
if (tvp != NULLVP) {
VREF(tvp);
un->un_flags |= UN_KLOCK;
}
vput(ap->a_tvp);
}
return (VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp));
bad:
vrele(fdvp);
vrele(fvp);
vput(tdvp);
if (tvp != NULLVP)
vput(tvp);
return (error);
}
static int
union_mkdir(ap)
struct vop_mkdir_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
struct vattr *a_vap;
} */ *ap;
{
struct union_node *dun = VTOUNION(ap->a_dvp);
struct vnode *dvp = dun->un_uppervp;
struct componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
if (dvp != NULLVP) {
struct vnode *vp;
int error;
FIXUP(dun, p);
dun->un_flags |= UN_KLOCK;
VOP_UNLOCK(ap->a_dvp, 0, p);
error = VOP_MKDIR(dvp, &vp, cnp, ap->a_vap);
if (error) {
dun->un_flags |= UN_ULOCK;
return (error);
}
VOP_UNLOCK(dvp, 0, p);
error = union_allocvp(ap->a_vpp, ap->a_dvp->v_mount, ap->a_dvp,
NULLVP, cnp, vp, NULLVP, 1);
if (error)
vput(vp);
vn_lock(ap->a_dvp, LK_EXCLUSIVE| LK_RETRY, p);
return (error);
}
return (EROFS);
}
static int
union_rmdir(ap)
struct vop_rmdir_args /* {
struct vnode *a_dvp;
struct vnode *a_vp;
struct componentname *a_cnp;
} */ *ap;
{
struct union_node *dun = VTOUNION(ap->a_dvp);
struct union_node *un = VTOUNION(ap->a_vp);
struct componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
int error;
if (dun->un_uppervp == NULLVP)
panic("union rmdir: null upper vnode");
if (un->un_uppervp != NULLVP) {
struct vnode *dvp = dun->un_uppervp;
struct vnode *vp = un->un_uppervp;
FIXUP(dun, p);
dun->un_flags |= UN_KLOCK;
VOP_UNLOCK(ap->a_dvp, 0, p);
FIXUP(un, p);
un->un_flags |= UN_KLOCK;
VOP_UNLOCK(ap->a_vp, 0, p);
if (union_dowhiteout(un, cnp->cn_cred, p))
cnp->cn_flags |= DOWHITEOUT;
error = VOP_RMDIR(dvp, vp, ap->a_cnp);
#if 0
/* XXX */
if (!error)
union_removed_upper(un);
#endif
dun->un_flags |= UN_ULOCK;
un->un_flags |= UN_ULOCK;
} else {
FIXUP(dun, p);
error = union_mkwhiteout(
MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount),
dun->un_uppervp, ap->a_cnp, un->un_path);
}
return (error);
}
static int
union_symlink(ap)
struct vop_symlink_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
struct vattr *a_vap;
char *a_target;
} */ *ap;
{
struct union_node *dun = VTOUNION(ap->a_dvp);
struct vnode *dvp = dun->un_uppervp;
struct componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
if (dvp != NULLVP) {
struct vnode *vp;
int error;
FIXUP(dun, p);
dun->un_flags |= UN_KLOCK;
VOP_UNLOCK(ap->a_dvp, 0, p);
error = VOP_SYMLINK(dvp, &vp, cnp, ap->a_vap, ap->a_target);
dun->un_flags |= UN_ULOCK;
*ap->a_vpp = NULLVP;
return (error);
}
return (EROFS);
}
/*
* union_readdir works in concert with getdirentries and
* readdir(3) to provide a list of entries in the unioned
* directories. getdirentries is responsible for walking
* down the union stack. readdir(3) is responsible for
* eliminating duplicate names from the returned data stream.
*/
static int
union_readdir(ap)
struct vop_readdir_args /* {
struct vnode *a_vp;
struct uio *a_uio;
struct ucred *a_cred;
int *a_eofflag;
u_long *a_cookies;
int a_ncookies;
} */ *ap;
{
struct union_node *un = VTOUNION(ap->a_vp);
struct vnode *uvp = un->un_uppervp;
struct proc *p = ap->a_uio->uio_procp;
if (uvp == NULLVP)
return (0);
FIXUP(un, p);
ap->a_vp = uvp;
return (VCALL(uvp, VOFFSET(vop_readdir), ap));
}
static int
union_readlink(ap)
struct vop_readlink_args /* {
struct vnode *a_vp;
struct uio *a_uio;
struct ucred *a_cred;
} */ *ap;
{
int error;
struct uio *uio = ap->a_uio;
struct proc *p = uio->uio_procp;
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
else
FIXUP(VTOUNION(ap->a_vp), p);
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_readlink), ap);
if (dolock)
VOP_UNLOCK(vp, 0, p);
return (error);
}
static int
union_abortop(ap)
struct vop_abortop_args /* {
struct vnode *a_dvp;
struct componentname *a_cnp;
} */ *ap;
{
int error;
struct componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
struct vnode *vp = OTHERVP(ap->a_dvp);
struct union_node *un = VTOUNION(ap->a_dvp);
int islocked = un->un_flags & UN_LOCKED;
int dolock = (vp == LOWERVP(ap->a_dvp));
if (islocked) {
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
else
FIXUP(VTOUNION(ap->a_dvp), p);
}
ap->a_dvp = vp;
error = VCALL(vp, VOFFSET(vop_abortop), ap);
if (islocked && dolock)
VOP_UNLOCK(vp, 0, p);
return (error);
}
static int
union_inactive(ap)
struct vop_inactive_args /* {
struct vnode *a_vp;
struct proc *a_p;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct proc *p = ap->a_p;
struct union_node *un = VTOUNION(vp);
struct vnode **vpp;
/*
* Do nothing (and _don't_ bypass).
* Wait to vrele lowervp until reclaim,
* so that until then our union_node is in the
* cache and reusable.
*
* NEEDSWORK: Someday, consider inactive'ing
* the lowervp and then trying to reactivate it
* with capabilities (v_id)
* like they do in the name lookup cache code.
* That's too much work for now.
*/
if (un->un_dircache != 0) {
for (vpp = un->un_dircache; *vpp != NULLVP; vpp++)
vrele(*vpp);
free(un->un_dircache, M_TEMP);
un->un_dircache = 0;
}
VOP_UNLOCK(vp, 0, p);
if ((un->un_flags & UN_CACHED) == 0)
vgone(vp);
return (0);
}
static int
union_reclaim(ap)
struct vop_reclaim_args /* {
struct vnode *a_vp;
} */ *ap;
{
union_freevp(ap->a_vp);
return (0);
}
static int
union_lock(ap)
struct vop_lock_args *ap;
{
struct vnode *vp = ap->a_vp;
struct proc *p = ap->a_p;
int flags = ap->a_flags;
struct union_node *un;
int error;
vop_nolock(ap);
/*
* Need to do real lockmgr-style locking here.
* in the mean time, draining won't work quite right,
* which could lead to a few race conditions.
* the following test was here, but is not quite right, we
* still need to take the lock:
if ((flags & LK_TYPE_MASK) == LK_DRAIN)
return (0);
*/
flags &= ~LK_INTERLOCK;
start:
un = VTOUNION(vp);
if (un->un_uppervp != NULLVP) {
if (((un->un_flags & UN_ULOCK) == 0) &&
(vp->v_usecount != 0)) {
error = vn_lock(un->un_uppervp, flags, p);
if (error)
return (error);
un->un_flags |= UN_ULOCK;
}
#ifdef DIAGNOSTIC
if (un->un_flags & UN_KLOCK) {
vprint("dangling upper lock", vp);
panic("union: dangling upper lock");
}
#endif
}
if (un->un_flags & UN_LOCKED) {
#ifdef DIAGNOSTIC
if (curproc && un->un_pid == curproc->p_pid &&
un->un_pid > -1 && curproc->p_pid > -1)
panic("union: locking against myself");
#endif
un->un_flags |= UN_WANT;
tsleep((caddr_t)&un->un_flags, PINOD, "unionlk2", 0);
goto start;
}
#ifdef DIAGNOSTIC
if (curproc)
un->un_pid = curproc->p_pid;
else
un->un_pid = -1;
#endif
un->un_flags |= UN_LOCKED;
return (0);
}
/*
* When operations want to vput() a union node yet retain a lock on
* the upper vnode (say, to do some further operations like link(),
* mkdir(), ...), they set UN_KLOCK on the union node, then call
* vput() which calls VOP_UNLOCK() and comes here. union_unlock()
* unlocks the union node (leaving the upper vnode alone), clears the
* KLOCK flag, and then returns to vput(). The caller then does whatever
* is left to do with the upper vnode, and ensures that it gets unlocked.
*
* If UN_KLOCK isn't set, then the upper vnode is unlocked here.
*/
static int
union_unlock(ap)
struct vop_unlock_args /* {
struct vnode *a_vp;
int a_flags;
struct proc *a_p;
} */ *ap;
{
struct union_node *un = VTOUNION(ap->a_vp);
struct proc *p = ap->a_p;
#ifdef DIAGNOSTIC
if ((un->un_flags & UN_LOCKED) == 0)
panic("union: unlock unlocked node");
if (curproc && un->un_pid != curproc->p_pid &&
curproc->p_pid > -1 && un->un_pid > -1)
panic("union: unlocking other process's union node");
#endif
un->un_flags &= ~UN_LOCKED;
if ((un->un_flags & (UN_ULOCK|UN_KLOCK)) == UN_ULOCK)
VOP_UNLOCK(un->un_uppervp, 0, p);
un->un_flags &= ~(UN_ULOCK|UN_KLOCK);
if (un->un_flags & UN_WANT) {
un->un_flags &= ~UN_WANT;
wakeup((caddr_t) &un->un_flags);
}
#ifdef DIAGNOSTIC
un->un_pid = 0;
#endif
vop_nounlock(ap);
return (0);
}
static int
union_bmap(ap)
struct vop_bmap_args /* {
struct vnode *a_vp;
daddr_t a_bn;
struct vnode **a_vpp;
daddr_t *a_bnp;
int *a_runp;
int *a_runb;
} */ *ap;
{
int error;
struct proc *p = curproc; /* XXX */
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
else
FIXUP(VTOUNION(ap->a_vp), p);
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_bmap), ap);
if (dolock)
VOP_UNLOCK(vp, 0, p);
return (error);
}
static int
union_print(ap)
struct vop_print_args /* {
struct vnode *a_vp;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
printf("\ttag VT_UNION, vp=%p, uppervp=%p, lowervp=%p\n",
vp, UPPERVP(vp), LOWERVP(vp));
if (UPPERVP(vp) != NULLVP)
vprint("union: upper", UPPERVP(vp));
if (LOWERVP(vp) != NULLVP)
vprint("union: lower", LOWERVP(vp));
return (0);
}
static int
union_islocked(ap)
struct vop_islocked_args /* {
struct vnode *a_vp;
} */ *ap;
{
return ((VTOUNION(ap->a_vp)->un_flags & UN_LOCKED) ? 1 : 0);
}
static int
union_pathconf(ap)
struct vop_pathconf_args /* {
struct vnode *a_vp;
int a_name;
int *a_retval;
} */ *ap;
{
int error;
struct proc *p = curproc; /* XXX */
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
else
FIXUP(VTOUNION(ap->a_vp), p);
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_pathconf), ap);
if (dolock)
VOP_UNLOCK(vp, 0, p);
return (error);
}
static int
union_advlock(ap)
struct vop_advlock_args /* {
struct vnode *a_vp;
caddr_t a_id;
int a_op;
struct flock *a_fl;
int a_flags;
} */ *ap;
{
register struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_advlock), ap));
}
/*
* XXX - vop_strategy must be hand coded because it has no
* vnode in its arguments.
* This goes away with a merged VM/buffer cache.
*/
static int
union_strategy(ap)
struct vop_strategy_args /* {
struct buf *a_bp;
} */ *ap;
{
struct buf *bp = ap->a_bp;
int error;
struct vnode *savedvp;
savedvp = bp->b_vp;
bp->b_vp = OTHERVP(bp->b_vp);
#ifdef DIAGNOSTIC
if (bp->b_vp == NULLVP)
panic("union_strategy: nil vp");
if (((bp->b_flags & B_READ) == 0) &&
(bp->b_vp == LOWERVP(savedvp)))
panic("union_strategy: writing to lowervp");
#endif
error = VOP_STRATEGY(bp);
bp->b_vp = savedvp;
return (error);
}
/*
* Global vfs data structures
*/
vop_t **union_vnodeop_p;
static struct vnodeopv_entry_desc union_vnodeop_entries[] = {
{ &vop_default_desc, (vop_t *) vop_defaultop },
{ &vop_abortop_desc, (vop_t *) union_abortop },
{ &vop_access_desc, (vop_t *) union_access },
{ &vop_advlock_desc, (vop_t *) union_advlock },
{ &vop_bmap_desc, (vop_t *) union_bmap },
{ &vop_close_desc, (vop_t *) union_close },
{ &vop_create_desc, (vop_t *) union_create },
{ &vop_fsync_desc, (vop_t *) union_fsync },
{ &vop_getattr_desc, (vop_t *) union_getattr },
{ &vop_inactive_desc, (vop_t *) union_inactive },
{ &vop_ioctl_desc, (vop_t *) union_ioctl },
{ &vop_islocked_desc, (vop_t *) union_islocked },
{ &vop_lease_desc, (vop_t *) union_lease },
{ &vop_link_desc, (vop_t *) union_link },
{ &vop_lock_desc, (vop_t *) union_lock },
{ &vop_lookup_desc, (vop_t *) union_lookup },
{ &vop_mkdir_desc, (vop_t *) union_mkdir },
{ &vop_mknod_desc, (vop_t *) union_mknod },
{ &vop_mmap_desc, (vop_t *) union_mmap },
{ &vop_open_desc, (vop_t *) union_open },
{ &vop_pathconf_desc, (vop_t *) union_pathconf },
{ &vop_poll_desc, (vop_t *) union_poll },
{ &vop_print_desc, (vop_t *) union_print },
{ &vop_read_desc, (vop_t *) union_read },
{ &vop_readdir_desc, (vop_t *) union_readdir },
{ &vop_readlink_desc, (vop_t *) union_readlink },
{ &vop_reclaim_desc, (vop_t *) union_reclaim },
{ &vop_remove_desc, (vop_t *) union_remove },
{ &vop_rename_desc, (vop_t *) union_rename },
{ &vop_revoke_desc, (vop_t *) union_revoke },
{ &vop_rmdir_desc, (vop_t *) union_rmdir },
{ &vop_setattr_desc, (vop_t *) union_setattr },
{ &vop_strategy_desc, (vop_t *) union_strategy },
{ &vop_symlink_desc, (vop_t *) union_symlink },
{ &vop_unlock_desc, (vop_t *) union_unlock },
{ &vop_whiteout_desc, (vop_t *) union_whiteout },
{ &vop_write_desc, (vop_t *) union_write },
{ NULL, NULL }
};
static struct vnodeopv_desc union_vnodeop_opv_desc =
{ &union_vnodeop_p, union_vnodeop_entries };
VNODEOP_SET(union_vnodeop_opv_desc);
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