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freebsd-nq/sys/fs/unionfs/union_vnops.c
Matthew Dillon e3a285c715 Make sure file after VOP_OPEN is VMIO'd when transfering control from 
a lower layer to an upper layer.  I'm not sure how necessary this is
    for reading.

    Fix bug in union_lookup() (note: there are probably still several bugs
    in union_lookup()).  This one set lerror as a side effect without
    setting lowervp, causing copyup code further on down to crash on a null
    lowervp pointer.  Changed the side effect to use a temporary variable
    instead.
1999-09-28 05:48:39 +00:00

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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
* $FreeBSD$
*/
#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 <sys/sysctl.h>
#include <miscfs/union/union.h>
#include <vm/vm.h>
#include <vm/vnode_pager.h>
#include <vm/vm_prot.h>
#include <vm/vm_page.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <vm/vm_extern.h>
int uniondebug = 0;
#if UDEBUG_ENABLED
SYSCTL_INT(_vfs, OID_AUTO, uniondebug, CTLFLAG_RW, &uniondebug, 0, "");
#else
SYSCTL_INT(_vfs, OID_AUTO, uniondebug, CTLFLAG_RD, &uniondebug, 0, "");
#endif
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 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_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 **dvp,
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_getpages __P((struct vop_getpages_args *ap));
static int union_putpages __P((struct vop_putpages_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 __inline
struct vnode *
union_lock_upper(struct union_node *un, struct proc *p)
{
struct vnode *uppervp;
if ((uppervp = un->un_uppervp) != NULL) {
VREF(uppervp);
vn_lock(uppervp, LK_EXCLUSIVE | LK_CANRECURSE | LK_RETRY, p);
}
KASSERT((uppervp == NULL || uppervp->v_usecount > 0), ("uppervp usecount is 0"));
return(uppervp);
}
static __inline
void
union_unlock_upper(struct vnode *uppervp, struct proc *p)
{
vput(uppervp);
}
static __inline
struct vnode *
union_lock_other(struct union_node *un, struct proc *p)
{
struct vnode *vp;
if (un->un_uppervp != NULL) {
vp = union_lock_upper(un, p);
} else if ((vp = un->un_lowervp) != NULL) {
VREF(vp);
vn_lock(vp, LK_EXCLUSIVE | LK_CANRECURSE | LK_RETRY, p);
}
return(vp);
}
static __inline
void
union_unlock_other(struct vnode *vp, struct proc *p)
{
vput(vp);
}
/*
* union_lookup:
*
* udvp must be exclusively locked on call and will remain
* exclusively locked on return. This is the mount point
* for out filesystem.
*
* dvp Our base directory, locked and referenced.
* The passed dvp will be dereferenced and unlocked on return
* and a new dvp will be returned which is locked and
* referenced in the same variable.
*
* vpp is filled in with the result if no error occured,
* locked and ref'd.
*
* If an error is returned, *vpp is set to NULLVP. If no
* error occurs, *vpp is returned with a reference and an
* exclusive lock.
*/
static int
union_lookup1(udvp, pdvp, vpp, cnp)
struct vnode *udvp;
struct vnode **pdvp;
struct vnode **vpp;
struct componentname *cnp;
{
int error;
struct proc *p = cnp->cn_proc;
struct vnode *dvp = *pdvp;
struct vnode *tdvp;
struct mount *mp;
/*
* 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;
dvp = dvp->v_mount->mnt_vnodecovered;
VREF(dvp);
vput(tdvp);
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p);
}
}
/*
* Set return dvp to be the upperdvp 'parent directory.
*/
*pdvp = dvp;
/*
* If the VOP_LOOKUP call generates an error, tdvp is invalid and no
* changes will have been made to dvp, so we are set to return.
*/
error = VOP_LOOKUP(dvp, &tdvp, cnp);
if (error) {
UDEBUG(("dvp %p error %d flags %lx\n", dvp, error, cnp->cn_flags));
*vpp = NULL;
return (error);
}
/*
* The parent directory will have been unlocked, unless lookup
* found the last component or if dvp == tdvp (tdvp must be locked).
*
* We want our dvp to remain locked and ref'd. We also want tdvp
* to remain locked and ref'd.
*/
UDEBUG(("parentdir %p result %p flag %lx\n", dvp, tdvp, cnp->cn_flags));
if (dvp != tdvp && (cnp->cn_flags & ISLASTCN) == 0)
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p);
/*
* 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).
*
* We use dvp as a temporary variable here, it is no longer related
* to the dvp above. However, we have to ensure that both *pdvp and
* tdvp are locked on return.
*/
dvp = tdvp;
while (
dvp != udvp &&
(dvp->v_type == VDIR) &&
(mp = dvp->v_mountedhere)
) {
int relock_pdvp = 0;
if (vfs_busy(mp, 0, 0, p))
continue;
if (dvp == *pdvp)
relock_pdvp = 1;
vput(dvp);
dvp = NULL;
error = VFS_ROOT(mp, &dvp);
vfs_unbusy(mp, p);
if (relock_pdvp)
vn_lock(*pdvp, LK_EXCLUSIVE | LK_RETRY, p);
if (error) {
*vpp = NULL;
return (error);
}
}
*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; /* starting dir */
struct union_node *dun = VTOUNION(dvp); /* associated union node */
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 = NULL;
int iswhiteout;
struct vattr va;
*ap->a_vpp = NULLVP;
/*
* 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);
}
/*
* For any lookup's we do, always return with the parent locked
*/
cnp->cn_flags |= LOCKPARENT;
lowerdvp = dun->un_lowervp;
uppervp = NULLVP;
lowervp = NULLVP;
iswhiteout = 0;
uerror = ENOENT;
lerror = ENOENT;
/*
* Get a private lock on uppervp and a reference, effectively
* taking it out of the union_node's control.
*
* We must lock upperdvp while holding our lock on dvp
* to avoid a deadlock.
*/
upperdvp = union_lock_upper(dun, p);
/*
* 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) {
/*
* We do not have to worry about the DOTDOT case, we've
* already unlocked dvp.
*/
UDEBUG(("A %p\n", upperdvp));
/*
* Do the lookup. We must supply a locked and referenced
* upperdvp to the function and will get a new locked and
* referenced upperdvp back with the old having been
* dereferenced.
*
* If an error is returned, uppervp will be NULLVP. If no
* error occurs, uppervp will be the locked and referenced
* return vnode or possibly NULL, depending on what is being
* requested. It is possible that the returned uppervp
* will be the same as upperdvp.
*/
uerror = union_lookup1(um->um_uppervp, &upperdvp, &uppervp, cnp);
UDEBUG((
"uerror %d upperdvp %p %d/%d, uppervp %p ref=%d/lck=%d\n",
uerror,
upperdvp,
upperdvp->v_usecount,
VOP_ISLOCKED(upperdvp),
uppervp,
(uppervp ? uppervp->v_usecount : -99),
(uppervp ? VOP_ISLOCKED(uppervp) : -99)
));
/*
* 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)) {
error = EROFS;
goto out;
}
/*
* Special case. If cn_consume != 0 skip out. The result
* of the lookup is transfered to our return variable. If
* an error occured we have to throw away the results.
*/
if (cnp->cn_consume != 0) {
if ((error = uerror) == 0) {
*ap->a_vpp = uppervp;
uppervp = NULL;
}
goto out;
}
/*
* Calculate whiteout, fall through
*/
if (uerror == ENOENT || uerror == EJUSTRETURN) {
if (cnp->cn_flags & ISWHITEOUT) {
iswhiteout = 1;
} else if (lowerdvp != NULLVP) {
int terror;
terror = VOP_GETATTR(upperdvp, &va,
cnp->cn_cred, cnp->cn_proc);
if (terror == 0 && (va.va_flags & OPAQUE))
iswhiteout = 1;
}
}
}
/*
* 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;
UDEBUG(("B %p\n", lowerdvp));
/*
* Force only LOOKUPs on the lower 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.
*
* union_lookup1() requires lowervp to be locked on entry,
* and it will be unlocked on return. The ref count will
* not change. On return lowervp doesn't represent anything
* to us so we NULL it out.
*/
VREF(lowerdvp);
vn_lock(lowerdvp, LK_EXCLUSIVE | LK_RETRY, p);
lerror = union_lookup1(um->um_lowervp, &lowerdvp, &lowervp, cnp);
if (lowerdvp == lowervp)
vrele(lowerdvp);
else
vput(lowerdvp);
lowerdvp = NULL; /* lowerdvp invalid after vput */
if (um->um_op == UNMNT_BELOW)
cnp->cn_cred = saved_cred;
cnp->cn_nameiop = nameiop;
if (cnp->cn_consume != 0 || lerror == EACCES) {
if ((error = lerror) == 0) {
*ap->a_vpp = lowervp;
lowervp = NULL;
}
goto out;
}
} else {
UDEBUG(("C %p\n", lowerdvp));
if ((cnp->cn_flags & ISDOTDOT) && dun->un_pvp != NULLVP) {
if ((lowervp = LOWERVP(dun->un_pvp)) != NULL) {
VREF(lowervp);
vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY, p);
lerror = 0;
}
}
}
/*
* Ok. Now we have uerror, uppervp, upperdvp, lerror, and lowervp.
*
* 1. If both layers returned an error, select the upper layer.
*
* 2. If the upper layer faile and the bottom layer succeeded,
* 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 button vnode is a directory, in which case
* create a new directory in the top layer and
* and fall through to 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.
*/
/* 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. */
KASSERT(uppervp == NULL, ("uppervp unexpectedly non-NULL"));
/*
* oops, uppervp has a problem, we may have to shadow.
*/
uerror = union_mkshadow(um, upperdvp, cnp, &uppervp);
if (uerror) {
error = uerror;
goto out;
}
}
}
/*
* Must call union_allocvp with both the upper and lower vnodes
* referenced and the upper vnode locked. ap->a_vpp is returned
* referenced and locked. lowervp, uppervp, and upperdvp are
* absorbed by union_allocvp() whether it succeeds or fails.
*
* upperdvp is the parent directory of uppervp which may be
* different, depending on the path, from dvp->un_uppervp. That's
* why it is a separate argument. Note that it must be unlocked.
*
* dvp must be locked on entry to the call and will be locked on
* return.
*/
if (uppervp && uppervp != upperdvp)
VOP_UNLOCK(uppervp, 0, p);
if (lowervp)
VOP_UNLOCK(lowervp, 0, p);
if (upperdvp)
VOP_UNLOCK(upperdvp, 0, p);
error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp,
uppervp, lowervp, 1);
UDEBUG(("Create %p = %p %p refs=%d\n", *ap->a_vpp, uppervp, lowervp, (*ap->a_vpp) ? ((*ap->a_vpp)->v_usecount) : -99));
uppervp = NULL;
upperdvp = NULL;
lowervp = NULL;
/*
* Termination Code
*
* - put away any extra junk laying around. Note that lowervp
* (if not NULL) will never be the same as *ap->a_vp and
* neither will uppervp, because when we set that state we
* NULL-out lowervp or uppervp. On the otherhand, upperdvp
* may match uppervp or *ap->a_vpp.
*
* - relock/unlock dvp if appropriate.
*/
out:
if (upperdvp) {
if (upperdvp == uppervp || upperdvp == *ap->a_vpp)
vrele(upperdvp);
else
vput(upperdvp);
}
if (uppervp)
vput(uppervp);
if (lowervp)
vput(lowervp);
/*
* Restore LOCKPARENT state
*/
if (!lockparent)
cnp->cn_flags &= ~LOCKPARENT;
UDEBUG(("Out %d vpp %p/%d lower %p upper %p\n", error, *ap->a_vpp,
((*ap->a_vpp) ? (*ap->a_vpp)->v_usecount : -99),
lowervp, uppervp));
/*
* dvp lock state, determine whether to relock dvp. dvp is expected
* to be locked on return if:
*
* - there was an error (except not EJUSTRETURN), or
* - we hit the last component and lockparent is true
*
* dvp_is_locked is the current state of the dvp lock, not counting
* the possibility that *ap->a_vpp == dvp (in which case it is locked
* anyway). Note that *ap->a_vpp == dvp only if no error occured.
*/
if (*ap->a_vpp != dvp) {
if ((error == 0 || error == EJUSTRETURN) &&
(!lockparent || (cnp->cn_flags & ISLASTCN) == 0)) {
VOP_UNLOCK(dvp, 0, p);
}
}
/*
* Diagnostics
*/
#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
return (error);
}
/*
* union_create:
*
* a_dvp is locked on entry and remains locked on return. a_vpp is returned
* locked if no error occurs, otherwise it is garbage.
*/
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 componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
struct vnode *dvp;
int error = EROFS;
if ((dvp = union_lock_upper(dun, p)) != NULL) {
struct vnode *vp;
struct mount *mp;
error = VOP_CREATE(dvp, &vp, cnp, ap->a_vap);
if (error == 0) {
mp = ap->a_dvp->v_mount;
VOP_UNLOCK(vp, 0, p);
UDEBUG(("ALLOCVP-1 FROM %p REFS %d\n", vp, vp->v_usecount));
error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP,
cnp, vp, NULLVP, 1);
UDEBUG(("ALLOCVP-2B FROM %p REFS %d\n", *ap->a_vpp, vp->v_usecount));
}
union_unlock_upper(dvp, p);
}
return (error);
}
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 vnode *uppervp;
int error = EOPNOTSUPP;
if ((uppervp = union_lock_upper(un, cnp->cn_proc)) != NULLVP) {
error = VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags);
union_unlock_upper(uppervp, cnp->cn_proc);
}
return(error);
}
/*
* union_mknod:
*
* a_dvp is locked on entry and should remain locked on return.
* a_vpp is garbagre whether an error occurs or not.
*/
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 componentname *cnp = ap->a_cnp;
struct vnode *dvp;
int error = EROFS;
if ((dvp = union_lock_upper(dun, cnp->cn_proc)) != NULL) {
struct vnode *vp;
error = VOP_MKNOD(dvp, &vp, cnp, ap->a_vap);
/* vp is garbage whether an error occurs or not */
union_unlock_upper(dvp, cnp->cn_proc);
}
return (error);
}
/*
* union_open:
*
* run open VOP. When opening the underlying vnode we have to mimic
* vn_open. What we *really* need to do to avoid screwups if the
* open semantics change is to call vn_open(). For example, ufs blows
* up if you open a file but do not vmio it prior to writing.
*/
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 = 0;
int tvpisupper = 1;
/*
* If there is an existing upper vp then simply open that.
* The upper vp takes precedence over the lower vp. When opening
* a lower vp for writing copy it to the uppervp and then open the
* uppervp.
*
* At the end of this section tvp will be left locked.
*/
if ((tvp = union_lock_upper(un, p)) == 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)) {
int docopy = !(mode & O_TRUNC);
error = union_copyup(un, docopy, cred, p);
tvp = union_lock_upper(un, p);
} else {
un->un_openl++;
VREF(tvp);
vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY, p);
tvpisupper = 0;
}
}
/*
* We are holding the correct vnode, open it
*/
if (error == 0)
error = VOP_OPEN(tvp, mode, cred, p);
/*
* Absolutely necessary or UFS will blowup
*/
if (error == 0 && vn_canvmio(tvp) == TRUE) {
error = vfs_object_create(tvp, p, cred);
}
/*
* Release any locks held
*/
if (tvpisupper) {
if (tvp)
union_unlock_upper(tvp, p);
} else {
vput(tvp);
}
return (error);
}
/*
* union_close:
*
* It is unclear whether a_vp is passed locked or unlocked. Whatever
* the case we do not change it.
*/
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;
/*
* 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);
default:
break;
}
}
if ((vp = union_lock_upper(un, p)) != NULLVP) {
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_access), ap);
union_unlock_upper(vp, p);
return(error);
}
if ((vp = un->un_lowervp) != NULLVP) {
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
ap->a_vp = vp;
/*
* Remove VWRITE from a_mode if our mount point is RW, because
* we want to allow writes and lowervp may be read-only.
*/
if ((un->un_vnode->v_mount->mnt_flag & MNT_RDONLY) == 0)
ap->a_mode &= ~VWRITE;
error = VCALL(vp, VOFFSET(vop_access), ap);
if (error == 0) {
struct union_mount *um;
um = MOUNTTOUNIONMOUNT(un->un_vnode->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);
}
return(error);
}
/*
* We handle getattr only to change the fsid and
* track object sizes
*
* 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.
*
* Because of this we cannot use our normal locking functions
* if we do not intend to lock the main a_vp node. At the moment
* we are running without any specific locking at all, but beware
* to any programmer that care must be taken if locking is added
* to this function.
*/
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;
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;
if ((vp = un->un_uppervp) != NULLVP) {
error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p);
if (error)
return (error);
/* XXX isn't this dangerouso without a lock? */
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);
/* XXX isn't this dangerous without a lock? */
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;
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;
struct vnode *uppervp;
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 && (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.
*/
error = EROFS;
if ((uppervp = union_lock_upper(un, p)) != NULLVP) {
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);
union_unlock_upper(uppervp, p);
}
return (error);
}
/*
* union_getpages:
*/
static int
union_getpages(struct vop_getpages_args *ap)
{
int r;
r = vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
ap->a_count, ap->a_reqpage);
return(r);
}
/*
* union_putpages:
*/
static int
union_putpages(struct vop_putpages_args *ap)
{
int r;
r = vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
ap->a_sync, ap->a_rtvals);
return(r);
}
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;
{
struct union_node *un = VTOUNION(ap->a_vp);
struct proc *p = ap->a_uio->uio_procp;
struct vnode *uvp;
int error;
uvp = union_lock_other(un, p);
KASSERT(uvp != NULL, ("union_read: backing vnode missing!"));
if (ap->a_vp->v_flag & VOBJBUF)
union_vm_coherency(ap->a_vp, ap->a_uio, 0);
error = VOP_READ(uvp, ap->a_uio, ap->a_ioflag, ap->a_cred);
union_unlock_other(uvp, 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 (uvp == 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;
{
struct union_node *un = VTOUNION(ap->a_vp);
struct proc *p = ap->a_uio->uio_procp;
struct vnode *uppervp;
int error;
if ((uppervp = union_lock_upper(un, p)) == NULLVP)
panic("union: missing upper layer in write");
/*
* Since our VM pages are associated with our vnode rather then
* the real vnode, and since we do not run our reads and writes
* through our own VM cache, we have a VM/VFS coherency problem.
* We solve them by invalidating or flushing the associated VM
* pages prior to allowing a normal read or write to occur.
*
* VM-backed writes (UIO_NOCOPY) have to be converted to normal
* writes because we are not cache-coherent. Normal writes need
* to be made coherent with our VM-backing store, which we do by
* first flushing any dirty VM pages associated with the write
* range, and then destroying any clean VM pages associated with
* the write range.
*/
if (ap->a_uio->uio_segflg == UIO_NOCOPY) {
ap->a_uio->uio_segflg = UIO_SYSSPACE;
} else if (ap->a_vp->v_flag & VOBJBUF) {
union_vm_coherency(ap->a_vp, ap->a_uio, 1);
}
error = VOP_WRITE(uppervp, 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);
}
union_unlock_upper(uppervp, p);
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;
{
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;
{
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;
{
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;
{
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;
struct union_node *un = VTOUNION(ap->a_vp);
if ((targetvp = union_lock_other(un, p)) != NULLVP) {
error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_waitfor, p);
union_unlock_other(targetvp, p);
}
return (error);
}
/*
* union_remove:
*
* Remove the specified cnp. The dvp and vp are passed to us locked
* and must remain locked on return.
*/
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;
struct vnode *uppervp;
struct vnode *upperdvp;
int error;
if ((upperdvp = union_lock_upper(dun, p)) == NULLVP)
panic("union remove: null upper vnode");
if ((uppervp = union_lock_upper(un, p)) != NULLVP) {
if (union_dowhiteout(un, cnp->cn_cred, p))
cnp->cn_flags |= DOWHITEOUT;
error = VOP_REMOVE(upperdvp, uppervp, cnp);
#if 0
/* XXX */
if (!error)
union_removed_upper(un);
#endif
union_unlock_upper(uppervp, p);
} else {
error = union_mkwhiteout(
MOUNTTOUNIONMOUNT(ap->a_dvp->v_mount),
upperdvp, ap->a_cnp, un->un_path);
}
union_unlock_upper(upperdvp, p);
return (error);
}
/*
* union_link:
*
* tdvp will be locked on entry, vp will not be locked on entry.
* tdvp should remain locked on return and vp should remain unlocked
* on return.
*/
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 0
if (dun->un_uppervp == tun->un_dirvp) {
if (dun->un_flags & UN_ULOCK) {
dun->un_flags &= ~UN_ULOCK;
VOP_UNLOCK(dun->un_uppervp, 0, p);
}
}
#endif
error = union_copyup(tun, 1, cnp->cn_cred, p);
#if 0
if (dun->un_uppervp == tun->un_dirvp) {
vn_lock(dun->un_uppervp,
LK_EXCLUSIVE | LK_RETRY, p);
dun->un_flags |= UN_ULOCK;
}
#endif
VOP_UNLOCK(ap->a_vp, 0, p);
}
vp = tun->un_uppervp;
}
if (error)
return (error);
/*
* Make sure upper is locked, then unlock the union directory we were
* called with to avoid a deadlock while we are calling VOP_LINK on
* the upper (with tdvp locked and vp not locked). Our ap->a_tdvp
* is expected to be locked on return.
*/
if ((tdvp = union_lock_upper(dun, p)) == NULLVP)
return (EROFS);
VOP_UNLOCK(ap->a_tdvp, 0, p); /* unlock calling node */
error = VOP_LINK(tdvp, vp, cnp); /* call link on upper */
/*
* We have to unlock tdvp prior to relocking our calling node in
* order to avoid a deadlock.
*/
union_unlock_upper(tdvp, p);
vn_lock(ap->a_tdvp, LK_EXCLUSIVE | LK_RETRY, p);
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;
/*
* Figure out what fdvp to pass to our upper or lower vnode. If we
* replace the fdvp, release the original one and ref the new one.
*/
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);
}
/*
* Figure out what fvp to pass to our upper or lower vnode. If we
* replace the fvp, release the original one and ref the new one.
*/
if (fvp->v_op == union_vnodeop_p) { /* always true */
struct union_node *un = VTOUNION(fvp);
#if 0
struct union_mount *um = MOUNTTOUNIONMOUNT(fvp->v_mount);
#endif
if (un->un_uppervp == NULLVP) {
switch(fvp->v_type) {
case VREG:
vn_lock(un->un_vnode, LK_EXCLUSIVE | LK_RETRY, ap->a_fcnp->cn_proc);
error = union_copyup(un, 1, ap->a_fcnp->cn_cred, ap->a_fcnp->cn_proc);
VOP_UNLOCK(un->un_vnode, 0, ap->a_fcnp->cn_proc);
if (error)
goto bad;
break;
case VDIR:
/*
* XXX not yet.
*
* There is only one way to rename a directory
* based in the lowervp, and that is to copy
* the entire directory hierarchy. Otherwise
* it would not last across a reboot.
*/
#if 0
vrele(fvp);
fvp = NULL;
vn_lock(fdvp, LK_EXCLUSIVE | LK_RETRY, ap->a_fcnp->cn_proc);
error = union_mkshadow(um, fdvp,
ap->a_fcnp, &un->un_uppervp);
VOP_UNLOCK(fdvp, 0, ap->a_fcnp->cn_proc);
if (un->un_uppervp)
VOP_UNLOCK(un->un_uppervp, 0, ap->a_fcnp->cn_proc);
if (error)
goto bad;
break;
#endif
default:
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);
}
/*
* Figure out what tdvp (destination directory) to pass to the
* lower level. If we replace it with uppervp, we need to vput the
* old one. The exclusive lock is transfered to what we will pass
* down in the VOP_RENAME and we replace uppervp with a simple
* reference.
*/
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;
}
/*
* new tdvp is a lock and reference on uppervp, put away
* the old tdvp.
*/
tdvp = union_lock_upper(un, ap->a_tcnp->cn_proc);
vput(ap->a_tdvp);
}
/*
* Figure out what tvp (destination file) to pass to the
* lower level.
*
* If the uppervp file does not exist put away the (wrong)
* file and change tvp to NULL.
*/
if (tvp != NULLVP && tvp->v_op == union_vnodeop_p) {
struct union_node *un = VTOUNION(tvp);
tvp = union_lock_upper(un, ap->a_tcnp->cn_proc);
vput(ap->a_tvp);
/* note: tvp may be NULL */
}
/*
* VOP_RENAME releases/vputs prior to returning, so we have no
* cleanup to do.
*/
return (VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp));
/*
* Error. We still have to release / vput the various elements.
*/
bad:
vrele(fdvp);
if (fvp)
vrele(fvp);
vput(tdvp);
if (tvp != NULLVP) {
if (tvp != tdvp)
vput(tvp);
else
vrele(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 componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
struct vnode *upperdvp;
int error = EROFS;
if ((upperdvp = union_lock_upper(dun, p)) != NULLVP) {
struct vnode *vp;
error = VOP_MKDIR(upperdvp, &vp, cnp, ap->a_vap);
union_unlock_upper(upperdvp, p);
if (error == 0) {
VOP_UNLOCK(vp, 0, p);
UDEBUG(("ALLOCVP-2 FROM %p REFS %d\n", vp, vp->v_usecount));
error = union_allocvp(ap->a_vpp, ap->a_dvp->v_mount,
ap->a_dvp, NULLVP, cnp, vp, NULLVP, 1);
UDEBUG(("ALLOCVP-2B FROM %p REFS %d\n", *ap->a_vpp, vp->v_usecount));
}
}
return (error);
}
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;
struct vnode *upperdvp;
struct vnode *uppervp;
int error;
if ((upperdvp = union_lock_upper(dun, p)) == NULLVP)
panic("union rmdir: null upper vnode");
if ((uppervp = union_lock_upper(un, p)) != NULLVP) {
if (union_dowhiteout(un, cnp->cn_cred, p))
cnp->cn_flags |= DOWHITEOUT;
error = VOP_RMDIR(upperdvp, uppervp, ap->a_cnp);
union_unlock_upper(uppervp, p);
} else {
error = union_mkwhiteout(
MOUNTTOUNIONMOUNT(ap->a_dvp->v_mount),
dun->un_uppervp, ap->a_cnp, un->un_path);
}
union_unlock_upper(upperdvp, p);
return (error);
}
/*
* union_symlink:
*
* dvp is locked on entry and remains locked on return. a_vpp is garbage
* (unused).
*/
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 componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
struct vnode *dvp;
int error = EROFS;
if ((dvp = union_lock_upper(dun, p)) != NULLVP) {
struct vnode *vp;
error = VOP_SYMLINK(dvp, &vp, cnp, ap->a_vap, ap->a_target);
/* vp is garbage whether an error occurs or not */
*ap->a_vpp = NULLVP;
union_unlock_upper(dvp, p);
}
return (error);
}
/*
* 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 proc *p = ap->a_uio->uio_procp;
struct vnode *uvp;
int error = 0;
if ((uvp = union_lock_upper(un, p)) != NULLVP) {
ap->a_vp = uvp;
error = VCALL(uvp, VOFFSET(vop_readdir), ap);
union_unlock_upper(uvp, p);
}
return(error);
}
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 union_node *un = VTOUNION(ap->a_vp);
struct uio *uio = ap->a_uio;
struct proc *p = uio->uio_procp;
struct vnode *vp;
vp = union_lock_other(un, p);
KASSERT(vp != NULL, ("union_readlink: backing vnode missing!"));
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_readlink), ap);
union_unlock_other(vp, p);
return (error);
}
/*
* union_abortop:
*
* dvp is locked on entry and left locked on return
*
*/
static int
union_abortop(ap)
struct vop_abortop_args /* {
struct vnode *a_dvp;
struct componentname *a_cnp;
} */ *ap;
{
struct componentname *cnp = ap->a_cnp;
struct proc *p = cnp->cn_proc;
struct union_node *un = VTOUNION(ap->a_dvp);
int islocked = VOP_ISLOCKED(ap->a_dvp);
struct vnode *vp;
int error;
if (islocked) {
vp = union_lock_other(un, p);
} else {
vp = OTHERVP(ap->a_dvp);
}
KASSERT(vp != NULL, ("union_abortop: backing vnode missing!"));
ap->a_dvp = vp;
error = VCALL(vp, VOFFSET(vop_abortop), ap);
if (islocked)
union_unlock_other(vp, p);
return (error);
}
/*
* union_inactive:
*
* Called with the vnode locked. We are expected to unlock the vnode.
*/
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;
}
#if 0
if ((un->un_flags & UN_ULOCK) && un->un_uppervp) {
un->un_flags &= ~UN_ULOCK;
VOP_UNLOCK(un->un_uppervp, 0, p);
}
#endif
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;
{
#if 0
struct vnode *vp = ap->a_vp;
struct proc *p = ap->a_p;
int flags = ap->a_flags;
struct union_node *un;
#endif
int error;
error = vop_stdlock(ap);
#if 0
un = VTOUNION(vp);
if (error == 0) {
/*
* Lock the upper if it exists and this is an exclusive lock
* request.
*/
if (un->un_uppervp != NULLVP &&
(flags & LK_TYPE_MASK) == LK_EXCLUSIVE) {
if ((un->un_flags & UN_ULOCK) == 0 && vp->v_usecount) {
error = vn_lock(un->un_uppervp, flags, p);
if (error) {
struct vop_unlock_args uap = { 0 };
uap.a_vp = ap->a_vp;
uap.a_flags = ap->a_flags;
uap.a_p = ap->a_p;
vop_stdunlock(&uap);
return (error);
}
un->un_flags |= UN_ULOCK;
}
}
}
#endif
return (error);
}
/*
* union_unlock:
*
* Unlock our union node. This also unlocks uppervp.
*/
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);
int error;
KASSERT((un->un_uppervp == NULL || un->un_uppervp->v_usecount > 0), ("uppervp usecount is 0"));
error = vop_stdunlock(ap);
#if 0
/*
* If no exclusive locks remain and we are holding an uppervp lock,
* remove the uppervp lock.
*/
if ((un->un_flags & UN_ULOCK) &&
lockstatus(&un->un_lock) != LK_EXCLUSIVE) {
un->un_flags &= ~UN_ULOCK;
VOP_UNLOCK(un->un_uppervp, LK_EXCLUSIVE, p);
}
#endif
return(error);
}
/*
* union_bmap:
*
* There isn't much we can do. We cannot push through to the real vnode
* to get to the underlying device because this will bypass data
* cached by the real vnode.
*
* For some reason we cannot return the 'real' vnode either, it seems
* to blow up memory maps.
*/
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;
{
return(EOPNOTSUPP);
}
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_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 union_node *un = VTOUNION(ap->a_vp);
struct vnode *vp;
vp = union_lock_other(un, p);
KASSERT(vp != NULL, ("union_pathconf: backing vnode missing!"));
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_pathconf), ap);
union_unlock_other(vp, 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
* YYY - and it is not coherent with anything
*
* vnode in its arguments.
* This goes away with a merged VM/buffer cache.
*/
static int
union_strategy(ap)
struct vop_strategy_args /* {
struct vnode *a_vp;
struct buf *a_bp;
} */ *ap;
{
struct buf *bp = ap->a_bp;
struct vnode *othervp = OTHERVP(bp->b_vp);
#ifdef DIAGNOSTIC
if (othervp == NULLVP)
panic("union_strategy: nil vp");
if (((bp->b_flags & B_READ) == 0) &&
(othervp == LOWERVP(bp->b_vp)))
panic("union_strategy: writing to lowervp");
#endif
return (VOP_STRATEGY(othervp, bp));
}
/*
* 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_getpages_desc, (vop_t *) union_getpages },
{ &vop_putpages_desc, (vop_t *) union_putpages },
{ &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 *) vop_stdislocked },
{ &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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