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NetBSD/sys/fs/union/union_vnops.c

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/* $NetBSD: union_vnops.c,v 1.49 2011/11/21 18:29:22 hannken Exp $ */
/*
* 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. 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 8.33 (Berkeley) 7/31/95
*/
/*
* Copyright (c) 1992, 1993, 1994, 1995 Jan-Simon Pendry.
*
* 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 8.33 (Berkeley) 7/31/95
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: union_vnops.c,v 1.49 2011/11/21 18:29:22 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <sys/buf.h>
#include <sys/queue.h>
#include <sys/lock.h>
#include <sys/kauth.h>
#include <fs/union/union.h>
#include <miscfs/genfs/genfs.h>
#include <miscfs/specfs/specdev.h>
int union_lookup(void *);
int union_create(void *);
int union_whiteout(void *);
int union_mknod(void *);
int union_open(void *);
int union_close(void *);
int union_access(void *);
int union_getattr(void *);
int union_setattr(void *);
int union_read(void *);
int union_write(void *);
int union_ioctl(void *);
int union_poll(void *);
int union_revoke(void *);
int union_mmap(void *);
int union_fsync(void *);
int union_seek(void *);
int union_remove(void *);
int union_link(void *);
int union_rename(void *);
int union_mkdir(void *);
int union_rmdir(void *);
int union_symlink(void *);
int union_readdir(void *);
int union_readlink(void *);
int union_abortop(void *);
int union_inactive(void *);
int union_reclaim(void *);
int union_lock(void *);
int union_unlock(void *);
int union_bmap(void *);
int union_print(void *);
int union_islocked(void *);
int union_pathconf(void *);
int union_advlock(void *);
int union_strategy(void *);
int union_bwrite(void *);
int union_getpages(void *);
int union_putpages(void *);
int union_kqfilter(void *);
static int union_lookup1(struct vnode *, struct vnode **,
struct vnode **, struct componentname *);
/*
* Global vfs data structures
*/
int (**union_vnodeop_p)(void *);
const struct vnodeopv_entry_desc union_vnodeop_entries[] = {
{ &vop_default_desc, vn_default_error },
{ &vop_lookup_desc, union_lookup }, /* lookup */
{ &vop_create_desc, union_create }, /* create */
{ &vop_whiteout_desc, union_whiteout }, /* whiteout */
{ &vop_mknod_desc, union_mknod }, /* mknod */
{ &vop_open_desc, union_open }, /* open */
{ &vop_close_desc, union_close }, /* close */
{ &vop_access_desc, union_access }, /* access */
{ &vop_getattr_desc, union_getattr }, /* getattr */
{ &vop_setattr_desc, union_setattr }, /* setattr */
{ &vop_read_desc, union_read }, /* read */
{ &vop_write_desc, union_write }, /* write */
{ &vop_ioctl_desc, union_ioctl }, /* ioctl */
{ &vop_poll_desc, union_poll }, /* select */
{ &vop_revoke_desc, union_revoke }, /* revoke */
{ &vop_mmap_desc, union_mmap }, /* mmap */
{ &vop_fsync_desc, union_fsync }, /* fsync */
{ &vop_seek_desc, union_seek }, /* seek */
{ &vop_remove_desc, union_remove }, /* remove */
{ &vop_link_desc, union_link }, /* link */
{ &vop_rename_desc, union_rename }, /* rename */
{ &vop_mkdir_desc, union_mkdir }, /* mkdir */
{ &vop_rmdir_desc, union_rmdir }, /* rmdir */
{ &vop_symlink_desc, union_symlink }, /* symlink */
{ &vop_readdir_desc, union_readdir }, /* readdir */
{ &vop_readlink_desc, union_readlink }, /* readlink */
{ &vop_abortop_desc, union_abortop }, /* abortop */
{ &vop_inactive_desc, union_inactive }, /* inactive */
{ &vop_reclaim_desc, union_reclaim }, /* reclaim */
{ &vop_lock_desc, union_lock }, /* lock */
{ &vop_unlock_desc, union_unlock }, /* unlock */
{ &vop_bmap_desc, union_bmap }, /* bmap */
{ &vop_strategy_desc, union_strategy }, /* strategy */
{ &vop_bwrite_desc, union_bwrite }, /* bwrite */
{ &vop_print_desc, union_print }, /* print */
{ &vop_islocked_desc, union_islocked }, /* islocked */
{ &vop_pathconf_desc, union_pathconf }, /* pathconf */
{ &vop_advlock_desc, union_advlock }, /* advlock */
{ &vop_getpages_desc, union_getpages }, /* getpages */
{ &vop_putpages_desc, union_putpages }, /* putpages */
{ &vop_kqfilter_desc, union_kqfilter }, /* kqfilter */
{ NULL, NULL }
};
const struct vnodeopv_desc union_vnodeop_opv_desc =
{ &union_vnodeop_p, union_vnodeop_entries };
#define NODE_IS_SPECIAL(vp) \
((vp)->v_type == VBLK || (vp)->v_type == VCHR || \
(vp)->v_type == VSOCK || (vp)->v_type == VFIFO)
static int
union_lookup1(struct vnode *udvp, struct vnode **dvpp, struct vnode **vpp,
struct componentname *cnp)
{
int error;
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_vflag & VV_ROOT)) {
/*
* 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;
VOP_UNLOCK(tdvp);
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
}
}
error = VOP_LOOKUP(dvp, &tdvp, cnp);
if (error)
return (error);
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, NULL))
continue;
vput(dvp);
error = VFS_ROOT(mp, &tdvp);
vfs_unbusy(mp, false, NULL);
if (error) {
return (error);
}
dvp = tdvp;
}
*vpp = dvp;
return (0);
}
int
union_lookup(void *v)
{
struct vop_lookup_args /* {
struct vnodeop_desc *a_desc;
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
} */ *ap = v;
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 union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount);
kauth_cred_t saved_cred = NULL;
int iswhiteout;
struct vattr va;
#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);
return (0);
}
#endif
if ((cnp->cn_flags & ISLASTCN) &&
(dvp->v_mount->mnt_flag & MNT_RDONLY) &&
(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
return (EROFS);
start:
upperdvp = dun->un_uppervp;
lowerdvp = dun->un_lowervp;
uppervp = NULLVP;
lowervp = NULLVP;
iswhiteout = 0;
/*
* 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) {
uerror = union_lookup1(um->um_uppervp, &upperdvp,
&uppervp, cnp);
if (cnp->cn_consume != 0) {
*ap->a_vpp = uppervp;
return (uerror);
}
if (uerror == ENOENT || uerror == EJUSTRETURN) {
if (cnp->cn_flags & ISWHITEOUT) {
iswhiteout = 1;
} else if (lowerdvp != NULLVP) {
lerror = VOP_GETATTR(upperdvp, &va,
cnp->cn_cred);
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);
/*
* 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);
if (cnp->cn_consume != 0) {
if (uppervp != NULLVP) {
if (uppervp == upperdvp)
vrele(uppervp);
else
vput(uppervp);
uppervp = NULLVP;
}
*ap->a_vpp = lowervp;
return (lerror);
}
} 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);
lerror = 0;
}
}
}
/*
* EJUSTRETURN is used by underlying filesystems to indicate that
* a directory modification op was started successfully.
* This will only happen in the upper layer, since
* the lower layer only does LOOKUPs.
* If this union is mounted read-only, bounce it now.
*/
if ((uerror == EJUSTRETURN) && (cnp->cn_flags & ISLASTCN) &&
(dvp->v_mount->mnt_flag & MNT_RDONLY) &&
((cnp->cn_nameiop == CREATE) || (cnp->cn_nameiop == RENAME)))
uerror = EROFS;
/*
* 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)) {
return (uerror);
}
/* case 2. */
if (uerror != 0 /* && (lerror == 0) */ ) {
if (lowervp->v_type == VDIR) { /* case 2b. */
/*
* We may be racing another process to make the
* upper-level shadow directory. Be careful with
* locks/etc!
* If we have to create a shadow directory and want
* to commit the node we have to restart the lookup
* to get the componentname right.
*/
if (upperdvp) {
VOP_UNLOCK(upperdvp);
uerror = union_mkshadow(um, upperdvp, cnp,
&uppervp);
vn_lock(upperdvp, LK_EXCLUSIVE | LK_RETRY);
if (uerror == 0 && cnp->cn_nameiop != LOOKUP) {
vput(uppervp);
if (lowervp != NULLVP)
vput(lowervp);
goto start;
}
}
if (uerror) {
if (lowervp != NULLVP) {
vput(lowervp);
lowervp = NULLVP;
}
return (uerror);
}
}
}
if (lowervp != NULLVP)
VOP_UNLOCK(lowervp);
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);
}
return (error);
}
int
union_create(void *v)
{
struct vop_create_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
struct vattr *a_vap;
} */ *ap = v;
struct union_node *un = VTOUNION(ap->a_dvp);
struct vnode *dvp = un->un_uppervp;
struct componentname *cnp = ap->a_cnp;
if (dvp != NULLVP) {
int error;
struct vnode *vp;
struct mount *mp;
vref(dvp);
un->un_flags |= UN_KLOCK;
mp = ap->a_dvp->v_mount;
vput(ap->a_dvp);
error = VOP_CREATE(dvp, &vp, cnp, ap->a_vap);
if (error)
return (error);
error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, cnp, vp,
NULLVP, 1);
if (error)
vput(vp);
return (error);
}
vput(ap->a_dvp);
return (EROFS);
}
int
union_whiteout(void *v)
{
struct vop_whiteout_args /* {
struct vnode *a_dvp;
struct componentname *a_cnp;
int a_flags;
} */ *ap = v;
struct union_node *un = VTOUNION(ap->a_dvp);
struct componentname *cnp = ap->a_cnp;
if (un->un_uppervp == NULLVP)
return (EOPNOTSUPP);
return (VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags));
}
int
union_mknod(void *v)
{
struct vop_mknod_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
struct vattr *a_vap;
} */ *ap = v;
struct union_node *un = VTOUNION(ap->a_dvp);
struct vnode *dvp = un->un_uppervp;
struct componentname *cnp = ap->a_cnp;
if (dvp != NULLVP) {
int error;
struct vnode *vp;
struct mount *mp;
vref(dvp);
un->un_flags |= UN_KLOCK;
mp = ap->a_dvp->v_mount;
vput(ap->a_dvp);
error = VOP_MKNOD(dvp, &vp, cnp, ap->a_vap);
if (error)
return (error);
error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP,
cnp, vp, NULLVP, 1);
if (error)
vput(vp);
return (error);
}
vput(ap->a_dvp);
return (EROFS);
}
int
union_open(void *v)
{
struct vop_open_args /* {
struct vnodeop_desc *a_desc;
struct vnode *a_vp;
int a_mode;
kauth_cred_t a_cred;
} */ *ap = v;
struct union_node *un = VTOUNION(ap->a_vp);
struct vnode *tvp;
int mode = ap->a_mode;
kauth_cred_t cred = ap->a_cred;
struct lwp *l = curlwp;
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, l);
if (error == 0)
error = VOP_OPEN(un->un_uppervp, mode, cred);
return (error);
}
/*
* Just open the lower vnode, but check for nodev mount flag
*/
if ((tvp->v_type == VBLK || tvp->v_type == VCHR) &&
(ap->a_vp->v_mount->mnt_flag & MNT_NODEV))
return ENXIO;
un->un_openl++;
vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_OPEN(tvp, mode, cred);
VOP_UNLOCK(tvp);
return (error);
}
/*
* Just open the upper vnode, checking for nodev mount flag first
*/
if ((tvp->v_type == VBLK || tvp->v_type == VCHR) &&
(ap->a_vp->v_mount->mnt_flag & MNT_NODEV))
return ENXIO;
error = VOP_OPEN(tvp, mode, cred);
return (error);
}
int
union_close(void *v)
{
struct vop_close_args /* {
struct vnode *a_vp;
int a_fflag;
kauth_cred_t a_cred;
} */ *ap = v;
struct union_node *un = VTOUNION(ap->a_vp);
struct vnode *vp;
int error;
bool do_lock;
vp = un->un_uppervp;
if (vp != NULLVP) {
do_lock = false;
} else {
KASSERT(un->un_openl > 0);
--un->un_openl;
vp = un->un_lowervp;
do_lock = true;
}
KASSERT(vp != NULLVP);
ap->a_vp = vp;
if (do_lock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = VCALL(vp, VOFFSET(vop_close), ap);
if (do_lock)
VOP_UNLOCK(vp);
return error;
}
/*
* 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.
*/
int
union_access(void *v)
{
struct vop_access_args /* {
struct vnodeop_desc *a_desc;
struct vnode *a_vp;
int a_mode;
kauth_cred_t a_cred;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
struct union_node *un = VTOUNION(vp);
int error = EACCES;
struct union_mount *um = MOUNTTOUNIONMOUNT(vp->v_mount);
/*
* Disallow write attempts on read-only file systems;
* unless the file is a socket, fifo, or a block or
* character device resident on the file system.
*/
if (ap->a_mode & VWRITE) {
switch (vp->v_type) {
case VDIR:
case VLNK:
case VREG:
if (vp->v_mount->mnt_flag & MNT_RDONLY)
return (EROFS);
break;
case VBAD:
case VBLK:
case VCHR:
case VSOCK:
case VFIFO:
case VNON:
default:
break;
}
}
if ((vp = un->un_uppervp) != NULLVP) {
ap->a_vp = vp;
return (VCALL(vp, VOFFSET(vop_access), ap));
}
if ((vp = un->un_lowervp) != NULLVP) {
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_access), ap);
if (error == 0) {
if (um->um_op == UNMNT_BELOW) {
ap->a_cred = um->um_cred;
error = VCALL(vp, VOFFSET(vop_access), ap);
}
}
VOP_UNLOCK(vp);
if (error)
return (error);
}
return (error);
}
/*
* We handle getattr only to change the fsid and
* track object sizes
*/
int
union_getattr(void *v)
{
struct vop_getattr_args /* {
struct vnode *a_vp;
struct vattr *a_vap;
kauth_cred_t a_cred;
} */ *ap = v;
int error;
struct union_node *un = VTOUNION(ap->a_vp);
struct vnode *vp = un->un_uppervp;
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.
*
* To make life more interesting, some filesystems don't keep
* track of link counts in the expected way, and return a
* link count of `1' for those directories; if either of the
* component directories returns a link count of `1', we return a 1.
*/
vap = ap->a_vap;
vp = un->un_uppervp;
if (vp != NULLVP) {
error = VOP_GETATTR(vp, vap, ap->a_cred);
if (error)
return (error);
mutex_enter(&un->un_lock);
union_newsize(ap->a_vp, vap->va_size, VNOVAL);
}
if (vp == NULLVP) {
vp = un->un_lowervp;
} else if (vp->v_type == VDIR) {
vp = un->un_lowervp;
if (vp != NULLVP)
vap = &va;
} else {
vp = NULLVP;
}
if (vp != NULLVP) {
if (vp == un->un_lowervp)
vn_lock(vp, LK_SHARED | LK_RETRY);
error = VOP_GETATTR(vp, vap, ap->a_cred);
if (vp == un->un_lowervp)
VOP_UNLOCK(vp);
if (error)
return (error);
mutex_enter(&un->un_lock);
union_newsize(ap->a_vp, VNOVAL, vap->va_size);
}
if ((vap != ap->a_vap) && (vap->va_type == VDIR)) {
/*
* Link count manipulation:
* - If both return "2", return 2 (no subdirs)
* - If one or the other return "1", return "1" (ENOCLUE)
*/
if ((ap->a_vap->va_nlink == 2) &&
(vap->va_nlink == 2))
;
else if (ap->a_vap->va_nlink != 1) {
if (vap->va_nlink == 1)
ap->a_vap->va_nlink = 1;
else
ap->a_vap->va_nlink += vap->va_nlink;
}
}
ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0];
return (0);
}
int
union_setattr(void *v)
{
struct vop_setattr_args /* {
struct vnode *a_vp;
struct vattr *a_vap;
kauth_cred_t a_cred;
} */ *ap = v;
struct vattr *vap = ap->a_vap;
struct vnode *vp = ap->a_vp;
struct union_node *un = VTOUNION(vp);
bool size_only; /* All but va_size are VNOVAL. */
int error;
size_only = (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);
if (!size_only && (vp->v_mount->mnt_flag & MNT_RDONLY))
return (EROFS);
if (vap->va_size != VNOVAL) {
switch (vp->v_type) {
case VDIR:
return (EISDIR);
case VCHR:
case VBLK:
case VSOCK:
case VFIFO:
break;
case VREG:
case VLNK:
default:
/*
* Disallow write attempts if the filesystem is
* mounted read-only.
*/
if (vp->v_mount->mnt_flag & MNT_RDONLY)
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, (vap->va_size != 0),
ap->a_cred, curlwp);
if (error)
return (error);
}
/*
* Try to set attributes in upper layer, ignore size change to zero
* for devices to handle O_TRUNC and return read-only filesystem error
* otherwise.
*/
if (un->un_uppervp != NULLVP) {
error = VOP_SETATTR(un->un_uppervp, vap, ap->a_cred);
if ((error == 0) && (vap->va_size != VNOVAL)) {
mutex_enter(&un->un_lock);
union_newsize(ap->a_vp, vap->va_size, VNOVAL);
}
} else {
KASSERT(un->un_lowervp != NULLVP);
if (NODE_IS_SPECIAL(un->un_lowervp)) {
if (size_only &&
(vap->va_size == 0 || vap->va_size == VNOVAL))
error = 0;
else
error = EROFS;
} else {
error = EROFS;
}
}
return (error);
}
int
union_read(void *v)
{
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
kauth_cred_t a_cred;
} */ *ap = v;
int error;
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);
if (dolock)
VOP_UNLOCK(vp);
/*
* 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;
off_t usz = VNOVAL, lsz = VNOVAL;
mutex_enter(&un->un_lock);
if (vp == un->un_uppervp) {
if (cur > un->un_uppersz)
usz = cur;
} else {
if (cur > un->un_lowersz)
lsz = cur;
}
if (usz != VNOVAL || lsz != VNOVAL)
union_newsize(ap->a_vp, usz, lsz);
else
mutex_exit(&un->un_lock);
}
return (error);
}
int
union_write(void *v)
{
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
kauth_cred_t a_cred;
} */ *ap = v;
int error;
struct vnode *vp;
struct union_node *un = VTOUNION(ap->a_vp);
vp = UPPERVP(ap->a_vp);
if (vp == NULLVP) {
vp = LOWERVP(ap->a_vp);
if (NODE_IS_SPECIAL(vp)) {
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag,
ap->a_cred);
VOP_UNLOCK(vp);
return error;
}
panic("union: missing upper layer in write");
}
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;
mutex_enter(&un->un_lock);
if (cur > un->un_uppersz)
union_newsize(ap->a_vp, cur, VNOVAL);
else
mutex_exit(&un->un_lock);
}
return (error);
}
int
union_ioctl(void *v)
{
struct vop_ioctl_args /* {
struct vnode *a_vp;
int a_command;
void *a_data;
int a_fflag;
kauth_cred_t a_cred;
} */ *ap = v;
struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_ioctl), ap));
}
int
union_poll(void *v)
{
struct vop_poll_args /* {
struct vnode *a_vp;
int a_events;
} */ *ap = v;
struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_poll), ap));
}
int
union_revoke(void *v)
{
struct vop_revoke_args /* {
struct vnode *a_vp;
int a_flags;
struct proc *a_p;
} */ *ap = v;
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); /* XXXAD?? */
return (0);
}
int
union_mmap(void *v)
{
struct vop_mmap_args /* {
struct vnode *a_vp;
vm_prot_t a_prot;
kauth_cred_t a_cred;
} */ *ap = v;
struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_mmap), ap));
}
int
union_fsync(void *v)
{
struct vop_fsync_args /* {
struct vnode *a_vp;
kauth_cred_t a_cred;
int a_flags;
off_t offhi;
off_t offlo;
} */ *ap = v;
int error = 0;
struct vnode *targetvp;
/*
* If vinvalbuf is calling us, it's a "shallow fsync" -- don't
* bother syncing the underlying vnodes, since (a) they'll be
* fsync'ed when reclaimed and (b) we could deadlock if
* they're locked; otherwise, pass it through to the
* underlying layer.
*/
if (ap->a_vp->v_type == VBLK || ap->a_vp->v_type == VCHR) {
error = spec_fsync(v);
if (error)
return error;
}
if (ap->a_flags & FSYNC_RECLAIM)
return 0;
targetvp = OTHERVP(ap->a_vp);
if (targetvp != NULLVP) {
int dolock = (targetvp == LOWERVP(ap->a_vp));
if (dolock)
vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_flags,
ap->a_offlo, ap->a_offhi);
if (dolock)
VOP_UNLOCK(targetvp);
}
return (error);
}
int
union_seek(void *v)
{
struct vop_seek_args /* {
struct vnode *a_vp;
off_t a_oldoff;
off_t a_newoff;
kauth_cred_t a_cred;
} */ *ap = v;
struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_seek), ap));
}
int
union_remove(void *v)
{
struct vop_remove_args /* {
struct vnode *a_dvp;
struct vnode *a_vp;
struct componentname *a_cnp;
} */ *ap = v;
int error;
struct union_node *dun = VTOUNION(ap->a_dvp);
struct union_node *un = VTOUNION(ap->a_vp);
struct componentname *cnp = ap->a_cnp;
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;
vref(dvp);
dun->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
vref(vp);
un->un_flags |= UN_KLOCK;
vput(ap->a_vp);
if (union_dowhiteout(un, cnp->cn_cred))
cnp->cn_flags |= DOWHITEOUT;
error = VOP_REMOVE(dvp, vp, cnp);
if (!error)
union_removed_upper(un);
} else {
error = union_mkwhiteout(
MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount),
dun->un_uppervp, ap->a_cnp, un);
vput(ap->a_dvp);
vput(ap->a_vp);
}
return (error);
}
int
union_link(void *v)
{
struct vop_link_args /* {
struct vnode *a_dvp;
struct vnode *a_vp;
struct componentname *a_cnp;
} */ *ap = v;
int error = 0;
struct componentname *cnp = ap->a_cnp;
struct union_node *dun;
struct vnode *vp;
struct vnode *dvp;
dun = VTOUNION(ap->a_dvp);
KASSERT((ap->a_cnp->cn_flags & LOCKPARENT) != 0);
if (ap->a_dvp->v_op != ap->a_vp->v_op) {
vp = ap->a_vp;
} else {
struct union_node *un = VTOUNION(ap->a_vp);
if (un->un_uppervp == NULLVP) {
const bool droplock = (dun->un_uppervp == un->un_dirvp);
/*
* Needs to be copied before we can link it.
*/
vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
if (droplock)
VOP_UNLOCK(dun->un_uppervp);
error = union_copyup(un, 1, cnp->cn_cred, curlwp);
if (droplock) {
vn_lock(dun->un_uppervp,
LK_EXCLUSIVE | LK_RETRY);
/*
* During copyup, we dropped the lock on the
* dir and invalidated any saved namei lookup
* state for the directory we'll be entering
* the link in. We need to re-run the lookup
* in that directory to reset any state needed
* for VOP_LINK.
* Call relookup on the union-layer to reset
* the state.
*/
vp = NULLVP;
if (dun->un_uppervp == NULLVP)
panic("union: null upperdvp?");
error = relookup(ap->a_dvp, &vp, ap->a_cnp, 0);
if (error) {
VOP_UNLOCK(ap->a_vp);
return EROFS; /* ? */
}
if (vp != NULLVP) {
/*
* The name we want to create has
* mysteriously appeared (a race?)
*/
error = EEXIST;
VOP_UNLOCK(ap->a_vp);
vput(ap->a_dvp);
vput(vp);
return (error);
}
}
VOP_UNLOCK(ap->a_vp);
}
vp = un->un_uppervp;
}
dvp = dun->un_uppervp;
if (dvp == NULLVP)
error = EROFS;
if (error) {
vput(ap->a_dvp);
return (error);
}
vref(dvp);
dun->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
return (VOP_LINK(dvp, vp, cnp));
}
int
union_rename(void *v)
{
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 = v;
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);
}
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);
}
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);
}
error = VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp);
goto out;
bad:
vput(tdvp);
if (tvp != NULLVP)
vput(tvp);
vrele(fdvp);
vrele(fvp);
out:
if (fdvp != ap->a_fdvp) {
vrele(ap->a_fdvp);
}
if (fvp != ap->a_fvp) {
vrele(ap->a_fvp);
}
return (error);
}
int
union_mkdir(void *v)
{
struct vop_mkdir_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
struct vattr *a_vap;
} */ *ap = v;
struct union_node *un = VTOUNION(ap->a_dvp);
struct vnode *dvp = un->un_uppervp;
struct componentname *cnp = ap->a_cnp;
if (dvp != NULLVP) {
int error;
struct vnode *vp;
vref(dvp);
un->un_flags |= UN_KLOCK;
VOP_UNLOCK(ap->a_dvp);
error = VOP_MKDIR(dvp, &vp, cnp, ap->a_vap);
if (error) {
vrele(ap->a_dvp);
return (error);
}
error = union_allocvp(ap->a_vpp, ap->a_dvp->v_mount, ap->a_dvp,
NULLVP, cnp, vp, NULLVP, 1);
if (error)
vput(vp);
vrele(ap->a_dvp);
return (error);
}
vput(ap->a_dvp);
return (EROFS);
}
int
union_rmdir(void *v)
{
struct vop_rmdir_args /* {
struct vnode *a_dvp;
struct vnode *a_vp;
struct componentname *a_cnp;
} */ *ap = v;
int error;
struct union_node *dun = VTOUNION(ap->a_dvp);
struct union_node *un = VTOUNION(ap->a_vp);
struct componentname *cnp = ap->a_cnp;
if (dun->un_uppervp == NULLVP)
panic("union rmdir: null upper vnode");
error = union_check_rmdir(un, cnp->cn_cred);
if (error) {
vput(ap->a_dvp);
vput(ap->a_vp);
return error;
}
if (un->un_uppervp != NULLVP) {
struct vnode *dvp = dun->un_uppervp;
struct vnode *vp = un->un_uppervp;
vref(dvp);
dun->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
vref(vp);
un->un_flags |= UN_KLOCK;
vput(ap->a_vp);
if (union_dowhiteout(un, cnp->cn_cred))
cnp->cn_flags |= DOWHITEOUT;
error = VOP_RMDIR(dvp, vp, ap->a_cnp);
if (!error)
union_removed_upper(un);
} else {
error = union_mkwhiteout(
MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount),
dun->un_uppervp, ap->a_cnp, un);
vput(ap->a_dvp);
vput(ap->a_vp);
}
return (error);
}
int
union_symlink(void *v)
{
struct vop_symlink_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
struct vattr *a_vap;
char *a_target;
} */ *ap = v;
struct union_node *un = VTOUNION(ap->a_dvp);
struct vnode *dvp = un->un_uppervp;
struct componentname *cnp = ap->a_cnp;
if (dvp != NULLVP) {
int error;
vref(dvp);
un->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
error = VOP_SYMLINK(dvp, ap->a_vpp, cnp, ap->a_vap,
ap->a_target);
return (error);
}
vput(ap->a_dvp);
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.
*/
int
union_readdir(void *v)
{
struct vop_readdir_args /* {
struct vnodeop_desc *a_desc;
struct vnode *a_vp;
struct uio *a_uio;
kauth_cred_t a_cred;
int *a_eofflag;
u_long *a_cookies;
int a_ncookies;
} */ *ap = v;
struct union_node *un = VTOUNION(ap->a_vp);
struct vnode *uvp = un->un_uppervp;
if (uvp == NULLVP)
return (0);
ap->a_vp = uvp;
return (VCALL(uvp, VOFFSET(vop_readdir), ap));
}
int
union_readlink(void *v)
{
struct vop_readlink_args /* {
struct vnode *a_vp;
struct uio *a_uio;
kauth_cred_t a_cred;
} */ *ap = v;
int error;
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_readlink), ap);
if (dolock)
VOP_UNLOCK(vp);
return (error);
}
int
union_abortop(void *v)
{
struct vop_abortop_args /* {
struct vnode *a_dvp;
struct componentname *a_cnp;
} */ *ap = v;
KASSERT(UPPERVP(ap->a_dvp) != NULL);
ap->a_dvp = UPPERVP(ap->a_dvp);
return VCALL(ap->a_dvp, VOFFSET(vop_abortop), ap);
}
int
union_inactive(void *v)
{
struct vop_inactive_args /* {
const struct vnodeop_desc *a_desc;
struct vnode *a_vp;
bool *a_recycle;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
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;
}
*ap->a_recycle = ((un->un_cflags & UN_CACHED) == 0);
VOP_UNLOCK(vp);
return (0);
}
int
union_reclaim(void *v)
{
struct vop_reclaim_args /* {
struct vnode *a_vp;
} */ *ap = v;
union_freevp(ap->a_vp);
return (0);
}
int
union_lock(void *v)
{
struct vop_lock_args /* {
struct vnode *a_vp;
int a_flags;
} */ *ap = v;
struct vnode *vp;
struct union_node *un;
int error;
un = VTOUNION(ap->a_vp);
mutex_enter(&un->un_lock);
for (;;) {
vp = LOCKVP(ap->a_vp);
mutex_exit(&un->un_lock);
if (vp == ap->a_vp)
error = genfs_lock(ap);
else
error = VOP_LOCK(vp, ap->a_flags);
if (error != 0)
return error;
mutex_enter(&un->un_lock);
if (vp == LOCKVP(ap->a_vp))
break;
if (vp == ap->a_vp)
genfs_unlock(ap);
else
VOP_UNLOCK(vp);
}
KASSERT((un->un_flags & UN_KLOCK) == 0);
mutex_exit(&un->un_lock);
return error;
}
/*
* 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.
*/
int
union_unlock(void *v)
{
struct vop_unlock_args /* {
struct vnode *a_vp;
int a_flags;
} */ *ap = v;
struct vnode *vp;
struct union_node *un;
un = VTOUNION(ap->a_vp);
vp = LOCKVP(ap->a_vp);
if ((un->un_flags & UN_KLOCK) == UN_KLOCK) {
KASSERT(vp != ap->a_vp);
un->un_flags &= ~UN_KLOCK;
return 0;
}
if (vp == ap->a_vp)
genfs_unlock(ap);
else
VOP_UNLOCK(vp);
return 0;
}
int
union_bmap(void *v)
{
struct vop_bmap_args /* {
struct vnode *a_vp;
daddr_t a_bn;
struct vnode **a_vpp;
daddr_t *a_bnp;
int *a_runp;
} */ *ap = v;
int error;
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_bmap), ap);
if (dolock)
VOP_UNLOCK(vp);
return (error);
}
int
union_print(void *v)
{
struct vop_print_args /* {
struct vnode *a_vp;
} */ *ap = v;
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));
if (VTOUNION(vp)->un_dircache) {
struct vnode **vpp;
for (vpp = VTOUNION(vp)->un_dircache; *vpp != NULLVP; vpp++)
vprint("dircache:", *vpp);
}
return (0);
}
int
union_islocked(void *v)
{
struct vop_islocked_args /* {
struct vnode *a_vp;
} */ *ap = v;
struct vnode *vp;
struct union_node *un;
un = VTOUNION(ap->a_vp);
mutex_enter(&un->un_lock);
vp = LOCKVP(ap->a_vp);
mutex_exit(&un->un_lock);
if (vp == ap->a_vp)
return genfs_islocked(ap);
else
return VOP_ISLOCKED(vp);
}
int
union_pathconf(void *v)
{
struct vop_pathconf_args /* {
struct vnode *a_vp;
int a_name;
int *a_retval;
} */ *ap = v;
int error;
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_pathconf), ap);
if (dolock)
VOP_UNLOCK(vp);
return (error);
}
int
union_advlock(void *v)
{
struct vop_advlock_args /* {
struct vnode *a_vp;
void *a_id;
int a_op;
struct flock *a_fl;
int a_flags;
} */ *ap = v;
struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_advlock), ap));
}
int
union_strategy(void *v)
{
struct vop_strategy_args /* {
struct vnode *a_vp;
struct buf *a_bp;
} */ *ap = v;
struct vnode *ovp = OTHERVP(ap->a_vp);
struct buf *bp = ap->a_bp;
KASSERT(ovp != NULLVP);
if (!NODE_IS_SPECIAL(ovp))
KASSERT((bp->b_flags & B_READ) || ovp != LOWERVP(bp->b_vp));
return (VOP_STRATEGY(ovp, bp));
}
int
union_bwrite(void *v)
{
struct vop_bwrite_args /* {
struct vnode *a_vp;
struct buf *a_bp;
} */ *ap = v;
struct vnode *ovp = OTHERVP(ap->a_vp);
struct buf *bp = ap->a_bp;
KASSERT(ovp != NULLVP);
if (!NODE_IS_SPECIAL(ovp))
KASSERT((bp->b_flags & B_READ) || ovp != LOWERVP(bp->b_vp));
return (VOP_BWRITE(ovp, bp));
}
int
union_getpages(void *v)
{
struct vop_getpages_args /* {
struct vnode *a_vp;
voff_t a_offset;
struct vm_page **a_m;
int *a_count;
int a_centeridx;
vm_prot_t a_access_type;
int a_advice;
int a_flags;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
KASSERT(mutex_owned(vp->v_interlock));
if (ap->a_flags & PGO_LOCKED) {
return EBUSY;
}
ap->a_vp = OTHERVP(vp);
KASSERT(vp->v_interlock == ap->a_vp->v_interlock);
/* Just pass the request on to the underlying layer. */
return VCALL(ap->a_vp, VOFFSET(vop_getpages), ap);
}
int
union_putpages(void *v)
{
struct vop_putpages_args /* {
struct vnode *a_vp;
voff_t a_offlo;
voff_t a_offhi;
int a_flags;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
KASSERT(mutex_owned(vp->v_interlock));
ap->a_vp = OTHERVP(vp);
KASSERT(vp->v_interlock == ap->a_vp->v_interlock);
if (ap->a_flags & PGO_RECLAIM) {
mutex_exit(vp->v_interlock);
return 0;
}
/* Just pass the request on to the underlying layer. */
return VCALL(ap->a_vp, VOFFSET(vop_putpages), ap);
}
int
union_kqfilter(void *v)
{
struct vop_kqfilter_args /* {
struct vnode *a_vp;
struct knote *a_kn;
} */ *ap = v;
int error;
/*
* We watch either the upper layer file (if it already exists),
* or the lower layer one. If there is lower layer file only
* at this moment, we will keep watching that lower layer file
* even if upper layer file would be created later on.
*/
if (UPPERVP(ap->a_vp))
error = VOP_KQFILTER(UPPERVP(ap->a_vp), ap->a_kn);
else if (LOWERVP(ap->a_vp))
error = VOP_KQFILTER(LOWERVP(ap->a_vp), ap->a_kn);
else {
/* panic? */
error = EOPNOTSUPP;
}
return (error);
}
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