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NetBSD/sys/miscfs/union/union_vnops.c

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/* $NetBSD: union_vnops.c,v 1.53 2001/07/04 21:38:00 chs Exp $ */
/*
* 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 8.33 (Berkeley) 7/31/95
*/
#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/types.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 <miscfs/union/union.h>
#include <miscfs/genfs/genfs.h>
int union_lookup __P((void *));
int union_create __P((void *));
int union_whiteout __P((void *));
int union_mknod __P((void *));
int union_open __P((void *));
int union_close __P((void *));
int union_access __P((void *));
int union_getattr __P((void *));
int union_setattr __P((void *));
int union_read __P((void *));
int union_write __P((void *));
int union_lease __P((void *));
int union_ioctl __P((void *));
int union_poll __P((void *));
int union_revoke __P((void *));
int union_mmap __P((void *));
int union_fsync __P((void *));
int union_seek __P((void *));
int union_remove __P((void *));
int union_link __P((void *));
int union_rename __P((void *));
int union_mkdir __P((void *));
int union_rmdir __P((void *));
int union_symlink __P((void *));
int union_readdir __P((void *));
int union_readlink __P((void *));
int union_abortop __P((void *));
int union_inactive __P((void *));
int union_reclaim __P((void *));
int union_lock __P((void *));
int union_unlock __P((void *));
int union_bmap __P((void *));
int union_print __P((void *));
int union_islocked __P((void *));
int union_pathconf __P((void *));
int union_advlock __P((void *));
int union_strategy __P((void *));
int union_getpages __P((void *));
static void union_fixup __P((struct union_node *));
static int union_lookup1 __P((struct vnode *, struct vnode **,
struct vnode **, struct componentname *));
/*
* Global vfs data structures
*/
int (**union_vnodeop_p) __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_lease_desc, union_lease }, /* lease */
{ &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_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 */
#ifdef notdef
{ &vop_blkatoff_desc, union_blkatoff }, /* blkatoff */
{ &vop_valloc_desc, union_valloc }, /* valloc */
{ &vop_vfree_desc, union_vfree }, /* vfree */
{ &vop_truncate_desc, union_truncate }, /* truncate */
{ &vop_update_desc, union_update }, /* update */
{ &vop_bwrite_desc, union_bwrite }, /* bwrite */
#endif
{ NULL, NULL }
};
const struct vnodeopv_desc union_vnodeop_opv_desc =
{ &union_vnodeop_p, union_vnodeop_entries };
#define FIXUP(un) { \
if (((un)->un_flags & UN_ULOCK) == 0) { \
union_fixup(un); \
} \
}
static void
union_fixup(un)
struct union_node *un;
{
vn_lock(un->un_uppervp, LK_EXCLUSIVE | LK_RETRY);
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 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);
}
}
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);
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))
continue;
error = VFS_ROOT(mp, &tdvp);
vfs_unbusy(mp);
if (error) {
vput(dvp);
return (error);
}
vput(dvp);
dvp = tdvp;
}
*vpp = dvp;
return (0);
}
int
union_lookup(v)
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;
int lockparent = cnp->cn_flags & LOCKPARENT;
struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount);
struct ucred *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);
if (!lockparent || !(cnp->cn_flags & ISLASTCN))
VOP_UNLOCK(ap->a_dvp, 0);
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);
cnp->cn_flags |= LOCKPARENT;
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) {
FIXUP(dun);
/*
* 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);
}
uerror = union_lookup1(um->um_uppervp, &upperdvp,
&uppervp, cnp);
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);
}
if (cnp->cn_consume != 0) {
*ap->a_vpp = uppervp;
if (!lockparent)
cnp->cn_flags &= ~LOCKPARENT;
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, 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);
/*
* 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);
if (cnp->cn_consume != 0) {
if (uppervp != NULLVP) {
if (uppervp == upperdvp)
vrele(uppervp);
else
vput(uppervp);
uppervp = NULLVP;
}
*ap->a_vpp = lowervp;
if (!lockparent)
cnp->cn_flags &= ~LOCKPARENT;
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;
}
}
}
if (!lockparent)
cnp->cn_flags &= ~LOCKPARENT;
/*
* 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!
*/
dun->un_flags &= ~UN_ULOCK;
VOP_UNLOCK(upperdvp, 0);
uerror = union_mkshadow(um, upperdvp, cnp, &uppervp);
vn_lock(upperdvp, LK_EXCLUSIVE | LK_RETRY);
dun->un_flags |= UN_ULOCK;
if (uerror) {
if (lowervp != NULLVP) {
vput(lowervp);
lowervp = NULLVP;
}
return (uerror);
}
}
}
if (lowervp != NULLVP)
VOP_UNLOCK(lowervp, 0);
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);
if (cnp->cn_namelen == 1 &&
cnp->cn_nameptr[0] == '.' &&
*ap->a_vpp != dvp) {
panic("union_lookup -> . (%p) != startdir (%p)\n",
ap->a_vpp, dvp);
}
}
return (error);
}
int
union_create(v)
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;
FIXUP(un);
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(v)
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);
FIXUP(un);
return (VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags));
}
int
union_mknod(v)
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;
FIXUP(un);
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);
if (vp != NULLVP) {
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(v)
void *v;
{
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 = v;
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, 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, p);
VOP_UNLOCK(tvp, 0);
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;
FIXUP(un);
error = VOP_OPEN(tvp, mode, cred, p);
return (error);
}
int
union_close(v)
void *v;
{
struct vop_close_args /* {
struct vnode *a_vp;
int a_fflag;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap = v;
struct union_node *un = VTOUNION(ap->a_vp);
struct vnode *vp;
vp = un->un_uppervp;
if (vp == NULLVP) {
#ifdef UNION_DIAGNOSTIC
if (un->un_openl <= 0)
panic("union: un_openl cnt");
#endif
--un->un_openl;
vp = un->un_lowervp;
}
#ifdef DIAGNOSTIC
if (vp == NULLVP) {
vprint("empty union vnode", vp);
panic("union_close empty vnode");
}
#endif
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.
*/
int
union_access(v)
void *v;
{
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 = 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) {
FIXUP(un);
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, 0);
if (error)
return (error);
}
return (error);
}
/*
* We handle getattr only to change the fsid and
* track object sizes
*/
int
union_getattr(v)
void *v;
{
struct vop_getattr_args /* {
struct vnode *a_vp;
struct vattr *a_vap;
struct ucred *a_cred;
struct proc *a_p;
} */ *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) {
/*
* 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);
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) {
vp = un->un_lowervp;
if (vp != NULLVP)
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)) {
/*
* 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_fsid.val[0];
return (0);
}
int
union_setattr(v)
void *v;
{
struct vop_setattr_args /* {
struct vnode *a_vp;
struct vattr *a_vap;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap = v;
struct vattr *vap = ap->a_vap;
struct vnode *vp = ap->a_vp;
struct union_node *un = VTOUNION(vp);
int error;
if ((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) &&
(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, 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);
error = VOP_SETATTR(un->un_uppervp, vap,
ap->a_cred, ap->a_p);
if ((error == 0) && (vap->va_size != VNOVAL))
union_newsize(ap->a_vp, vap->va_size, VNOVAL);
} else {
error = EROFS;
}
return (error);
}
int
union_read(v)
void *v;
{
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *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);
else
FIXUP(VTOUNION(ap->a_vp));
error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);
if (dolock)
VOP_UNLOCK(vp, 0);
/*
* 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);
}
int
union_write(v)
void *v;
{
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *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)
panic("union: missing upper layer in write");
FIXUP(un);
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);
}
int
union_lease(v)
void *v;
{
struct vop_lease_args /* {
struct vnode *a_vp;
struct proc *a_p;
struct ucred *a_cred;
int a_flag;
} */ *ap = v;
struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_lease), ap));
}
int
union_ioctl(v)
void *v;
{
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 = v;
struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_ioctl), ap));
}
int
union_poll(v)
void *v;
{
struct vop_poll_args /* {
struct vnode *a_vp;
int a_events;
struct proc *a_p;
} */ *ap = v;
struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_poll), ap));
}
int
union_revoke(v)
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);
return (0);
}
int
union_mmap(v)
void *v;
{
struct vop_mmap_args /* {
struct vnode *a_vp;
int a_fflags;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap = v;
struct vnode *ovp = OTHERVP(ap->a_vp);
ap->a_vp = ovp;
return (VCALL(ovp, VOFFSET(vop_mmap), ap));
}
int
union_fsync(v)
void *v;
{
struct vop_fsync_args /* {
struct vnode *a_vp;
struct ucred *a_cred;
int a_flags;
off_t offhi;
off_t offlo;
struct proc *a_p;
} */ *ap = v;
int error = 0;
struct proc *p;
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_flags & FSYNC_RECLAIM)
return 0;
targetvp = OTHERVP(ap->a_vp);
p = ap->a_p;
if (targetvp != NULLVP) {
int dolock = (targetvp == LOWERVP(ap->a_vp));
if (dolock)
vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY);
else
FIXUP(VTOUNION(ap->a_vp));
error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_flags,
ap->a_offlo, ap->a_offhi, p);
if (dolock)
VOP_UNLOCK(targetvp, 0);
}
return (error);
}
int
union_seek(v)
void *v;
{
struct vop_seek_args /* {
struct vnode *a_vp;
off_t a_oldoff;
off_t a_newoff;
struct ucred *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(v)
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;
FIXUP(dun);
VREF(dvp);
dun->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
FIXUP(un);
VREF(vp);
un->un_flags |= UN_KLOCK;
vput(ap->a_vp);
if (union_dowhiteout(un, cnp->cn_cred, cnp->cn_proc))
cnp->cn_flags |= DOWHITEOUT;
error = VOP_REMOVE(dvp, vp, cnp);
if (!error)
union_removed_upper(un);
} else {
FIXUP(dun);
error = union_mkwhiteout(
MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount),
dun->un_uppervp, ap->a_cnp, un->un_path);
vput(ap->a_dvp);
vput(ap->a_vp);
}
return (error);
}
int
union_link(v)
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 proc *p = cnp->cn_proc;
struct union_node *dun;
struct vnode *vp;
struct vnode *dvp;
dun = VTOUNION(ap->a_dvp);
#ifdef DIAGNOSTIC
if (!(ap->a_cnp->cn_flags & LOCKPARENT)) {
printf("union_link called without LOCKPARENT set!\n");
error = EIO; /* need some error code for "caller is a bozo" */
} else
#endif
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) {
/*
* Needs to be copied before we can link it.
*/
vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
if (dun->un_uppervp == un->un_dirvp) {
dun->un_flags &= ~UN_ULOCK;
VOP_UNLOCK(dun->un_uppervp, 0);
}
error = union_copyup(un, 1, cnp->cn_cred, p);
if (dun->un_uppervp == un->un_dirvp) {
/*
* 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?");
/*
* relookup starts with an unlocked node,
* and since LOCKPARENT is set returns
* the starting directory locked.
*/
VOP_UNLOCK(ap->a_dvp, 0);
error = relookup(ap->a_dvp, &vp, ap->a_cnp);
if (error) {
vrele(ap->a_dvp);
VOP_UNLOCK(ap->a_vp, 0);
return EROFS; /* ? */
}
if (vp != NULLVP) {
/*
* The name we want to create has
* mysteriously appeared (a race?)
*/
error = EEXIST;
VOP_UNLOCK(ap->a_vp, 0);
goto croak;
}
}
VOP_UNLOCK(ap->a_vp, 0);
}
vp = un->un_uppervp;
}
dvp = dun->un_uppervp;
if (dvp == NULLVP)
error = EROFS;
if (error) {
croak:
vput(ap->a_dvp);
return (error);
}
FIXUP(dun);
VREF(dvp);
dun->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
return (VOP_LINK(dvp, vp, cnp));
}
int
union_rename(v)
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);
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);
}
int
union_mkdir(v)
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;
FIXUP(un);
VREF(dvp);
un->un_flags |= UN_KLOCK;
VOP_UNLOCK(ap->a_dvp, 0);
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);
vrele(ap->a_dvp);
if (error)
vput(vp);
return (error);
}
vput(ap->a_dvp);
return (EROFS);
}
int
union_rmdir(v)
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");
if (un->un_uppervp != NULLVP) {
struct vnode *dvp = dun->un_uppervp;
struct vnode *vp = un->un_uppervp;
FIXUP(dun);
VREF(dvp);
dun->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
FIXUP(un);
VREF(vp);
un->un_flags |= UN_KLOCK;
vput(ap->a_vp);
if (union_dowhiteout(un, cnp->cn_cred, cnp->cn_proc))
cnp->cn_flags |= DOWHITEOUT;
error = VOP_RMDIR(dvp, vp, ap->a_cnp);
if (!error)
union_removed_upper(un);
} else {
FIXUP(dun);
error = union_mkwhiteout(
MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount),
dun->un_uppervp, ap->a_cnp, un->un_path);
vput(ap->a_dvp);
vput(ap->a_vp);
}
return (error);
}
int
union_symlink(v)
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;
struct vnode *vp;
FIXUP(un);
VREF(dvp);
un->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
error = VOP_SYMLINK(dvp, &vp, cnp, ap->a_vap, ap->a_target);
*ap->a_vpp = NULLVP;
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(v)
void *v;
{
struct vop_readdir_args /* {
struct vnodeop_desc *a_desc;
struct vnode *a_vp;
struct uio *a_uio;
struct ucred *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);
FIXUP(un);
ap->a_vp = uvp;
return (VCALL(uvp, VOFFSET(vop_readdir), ap));
}
int
union_readlink(v)
void *v;
{
struct vop_readlink_args /* {
struct vnode *a_vp;
struct uio *a_uio;
struct ucred *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);
else
FIXUP(VTOUNION(ap->a_vp));
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_readlink), ap);
if (dolock)
VOP_UNLOCK(vp, 0);
return (error);
}
int
union_abortop(v)
void *v;
{
struct vop_abortop_args /* {
struct vnode *a_dvp;
struct componentname *a_cnp;
} */ *ap = v;
int error;
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);
else
FIXUP(VTOUNION(ap->a_dvp));
}
ap->a_dvp = vp;
error = VCALL(vp, VOFFSET(vop_abortop), ap);
if (islocked && dolock)
VOP_UNLOCK(vp, 0);
return (error);
}
int
union_inactive(v)
void *v;
{
struct vop_inactive_args /* {
struct vnode *a_vp;
struct proc *a_p;
} */ *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;
}
VOP_UNLOCK(vp, 0);
if ((un->un_flags & UN_CACHED) == 0)
vgone(vp);
return (0);
}
int
union_reclaim(v)
void *v;
{
struct vop_reclaim_args /* {
struct vnode *a_vp;
} */ *ap = v;
union_freevp(ap->a_vp);
return (0);
}
int
union_lock(v)
void *v;
{
struct vop_lock_args /* {
struct vnode *a_vp;
int a_flags;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
int flags = ap->a_flags;
struct union_node *un;
int error;
#ifdef DIAGNOSTIC
int drain = 0;
#endif
genfs_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;
un = VTOUNION(vp);
#ifdef DIAGNOSTIC
if (un->un_flags & (UN_DRAINING|UN_DRAINED)) {
if (un->un_flags & UN_DRAINED)
panic("union: %p: warning: locking decommissioned lock\n", vp);
if ((flags & LK_TYPE_MASK) != LK_RELEASE)
panic("union: %p: non-release on draining lock: %d\n",
vp, flags & LK_TYPE_MASK);
un->un_flags &= ~UN_DRAINING;
if ((flags & LK_REENABLE) == 0)
un->un_flags |= UN_DRAINED;
}
#endif
/*
* Don't pass DRAIN through to sub-vnode lock; keep track of
* DRAIN state at this level, and just get an exclusive lock
* on the underlying vnode.
*/
if ((flags & LK_TYPE_MASK) == LK_DRAIN) {
#ifdef DIAGNOSTIC
drain = 1;
#endif
flags = LK_EXCLUSIVE | (flags & ~LK_TYPE_MASK);
}
start:
un = VTOUNION(vp);
if (un->un_uppervp != NULLVP) {
if (((un->un_flags & UN_ULOCK) == 0) &&
(vp->v_usecount != 0)) {
/*
* We MUST always use the order of: take upper
* vp lock, manipulate union node flags, drop
* upper vp lock. This code must not be an
*/
error = vn_lock(un->un_uppervp, flags);
if (error)
return (error);
un->un_flags |= UN_ULOCK;
}
#ifdef DIAGNOSTIC
if (un->un_flags & UN_KLOCK) {
vprint("union: dangling klock", vp);
panic("union: dangling upper lock (%p)", vp);
}
#endif
}
/* XXX ignores LK_NOWAIT */
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_WANTED;
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;
if (drain)
un->un_flags |= UN_DRAINING;
#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.
*/
int
union_unlock(v)
void *v;
{
struct vop_unlock_args /* {
struct vnode *a_vp;
int a_flags;
} */ *ap = v;
struct union_node *un = VTOUNION(ap->a_vp);
#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");
if (un->un_flags & UN_DRAINED)
panic("union: %p: warning: unlocking decommissioned lock\n", ap->a_vp);
#endif
un->un_flags &= ~UN_LOCKED;
if ((un->un_flags & (UN_ULOCK|UN_KLOCK)) == UN_ULOCK)
VOP_UNLOCK(un->un_uppervp, 0);
un->un_flags &= ~(UN_ULOCK|UN_KLOCK);
if (un->un_flags & UN_WANTED) {
un->un_flags &= ~UN_WANTED;
wakeup((caddr_t) &un->un_flags);
}
#ifdef DIAGNOSTIC
un->un_pid = 0;
if (un->un_flags & UN_DRAINING) {
un->un_flags |= UN_DRAINED;
un->un_flags &= ~UN_DRAINING;
}
#endif
genfs_nounlock(ap);
return (0);
}
int
union_bmap(v)
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);
else
FIXUP(VTOUNION(ap->a_vp));
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_bmap), ap);
if (dolock)
VOP_UNLOCK(vp, 0);
return (error);
}
int
union_print(v)
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(v)
void *v;
{
struct vop_islocked_args /* {
struct vnode *a_vp;
} */ *ap = v;
return ((VTOUNION(ap->a_vp)->un_flags & UN_LOCKED) ? 1 : 0);
}
int
union_pathconf(v)
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);
else
FIXUP(VTOUNION(ap->a_vp));
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_pathconf), ap);
if (dolock)
VOP_UNLOCK(vp, 0);
return (error);
}
int
union_advlock(v)
void *v;
{
struct vop_advlock_args /* {
struct vnode *a_vp;
caddr_t 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));
}
/*
* XXX - vop_strategy must be hand coded because it has no
* vnode in its arguments.
* This goes away with a merged VM/buffer cache.
*/
int
union_strategy(v)
void *v;
{
struct vop_strategy_args /* {
struct buf *a_bp;
} */ *ap = v;
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);
}
int
union_getpages(v)
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;
int error;
/*
* just call into the underlying layer to get the pages.
*/
ap->a_vp = OTHERVP(vp);
simple_unlock(&vp->v_uvm.u_obj.vmobjlock);
simple_lock(&ap->a_vp->v_uvm.u_obj.vmobjlock);
error = VCALL(ap->a_vp, VOFFSET(vop_getpages), ap);
return error;
}
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