freebsd-skq/sys/fs/unionfs/union_vnops.c
bde 449a11eb88 Introduced a type `vop_t' for vnode operation functions and used
it 1138 times (:-() in casts and a few more times in declarations.
This change is null for the i386.

The type has to be `typedef int vop_t(void *)' and not `typedef
int vop_t()' because `gcc -Wstrict-prototypes' warns about the
latter.  Since vnode op functions are called with args of different
(struct pointer) types, neither of these function types is any use
for type checking of the arg, so it would be preferable not to use
the complete function type, especially since using the complete
type requires adding 1138 casts to avoid compiler warnings and
another 40+ casts to reverse the function pointer conversions before
calling the functions.
1995-11-09 08:17:23 +00:00

1506 lines
32 KiB
C

/*
* Copyright (c) 1992, 1993, 1994 The Regents of the University of California.
* Copyright (c) 1992, 1993, 1994 Jan-Simon Pendry.
* 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 8.6 (Berkeley) 2/17/94
* $Id: union_vnops.c,v 1.12 1995/09/04 00:20:41 dyson Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/kernel.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 <miscfs/union/union.h>
/* FIXUP throws the lock on the uppervp vnode if the union_node is already
* locked and the uppervp vnode is not. Before, this was thrown regardless
* of the state of the union_node which resulted in locked vnodes which
* were never unlocked (since the union would never be unlocked).
*/
#define FIXUP(un) { \
if (((un)->un_flags & (UN_LOCKED|UN_ULOCK)) == UN_LOCKED) { \
union_fixup(un); \
} \
}
static void
union_fixup(un)
struct union_node *un;
{
VOP_LOCK(un->un_uppervp);
un->un_flags |= UN_ULOCK;
}
static int
union_lookup1(udvp, dvp, vpp, cnp)
struct vnode *udvp;
struct vnode *dvp;
struct vnode **vpp;
struct componentname *cnp;
{
int error;
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) {
for (;;) {
/*
* Don't do the NOCROSSMOUNT check
* at this level. By definition,
* union fs deals with namespaces, not
* filesystems.
*/
if ((dvp->v_flag & VROOT) == 0)
break;
tdvp = dvp;
dvp = dvp->v_mount->mnt_vnodecovered;
vput(tdvp);
VREF(dvp);
VOP_LOCK(dvp);
}
}
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))
VOP_LOCK(dvp);
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 (mp->mnt_flag & MNT_MLOCK) {
mp->mnt_flag |= MNT_MWAIT;
(void) tsleep((caddr_t) mp, PVFS, "unlkup", 0);
continue;
}
error = VFS_ROOT(mp, &tdvp);
if (error) {
vput(dvp);
return (error);
}
vput(dvp);
dvp = tdvp;
}
*vpp = dvp;
return (0);
}
int
union_lookup(ap)
struct vop_lookup_args /* {
struct vnodeop_desc *a_desc;
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
} */ *ap;
{
int error;
int uerror, lerror;
struct vnode *uppervp, *lowervp;
struct vnode *upperdvp, *lowerdvp;
struct vnode *dvp = ap->a_dvp;
struct union_node *dun = VTOUNION(dvp);
struct componentname *cnp = ap->a_cnp;
int lockparent = cnp->cn_flags & LOCKPARENT;
struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount);
struct ucred *saved_cred = 0;
cnp->cn_flags |= LOCKPARENT;
upperdvp = dun->un_uppervp;
lowerdvp = dun->un_lowervp;
uppervp = NULLVP;
lowervp = NULLVP;
/*
* 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) {
FIXUP(dun);
uerror = union_lookup1(um->um_uppervp, upperdvp,
&uppervp, cnp);
/*if (uppervp == upperdvp)
dun->un_flags |= UN_KLOCK;*/
if (cnp->cn_consume != 0) {
*ap->a_vpp = uppervp;
if (!lockparent)
cnp->cn_flags &= ~LOCKPARENT;
return (uerror);
}
} 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) {
int nameiop;
VOP_LOCK(lowerdvp);
/*
* 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;
}
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) {
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 (!lockparent)
cnp->cn_flags &= ~LOCKPARENT;
/*
* at this point, we have uerror and lerror indicating
* possible errors with the lookups in the upper and lower
* layers. additionally, uppervp and lowervp are (locked)
* references to existing vnodes in the upper and lower layers.
*
* there are now three cases to consider.
* 1. if both layers returned an error, then return whatever
* error the upper layer generated.
*
* 2. if the top layer failed and the bottom layer succeeded
* then two subcases occur.
* a. the bottom vnode is not a directory, in which
* case just return a new union vnode referencing
* an empty top layer and the existing bottom layer.
* b. the bottom vnode is a directory, in which case
* create a new directory in the top-level and
* continue as in case 3.
*
* 3. if the top layer succeeded then return a new union
* vnode referencing whatever the new top layer and
* whatever the bottom layer returned.
*/
*ap->a_vpp = NULLVP;
/* case 1. */
if ((uerror != 0) && (lerror != 0)) {
return (uerror);
}
/* case 2. */
if (uerror != 0 /* && (lerror == 0) */ ) {
if (lowervp->v_type == VDIR) { /* case 2b. */
dun->un_flags &= ~UN_ULOCK;
VOP_UNLOCK(upperdvp);
uerror = union_mkshadow(um, upperdvp, cnp, &uppervp);
VOP_LOCK(upperdvp);
dun->un_flags |= UN_ULOCK;
if (uerror) {
if (lowervp) {
vput(lowervp);
lowervp = NULLVP;
}
return (uerror);
}
}
}
if (lowervp)
VOP_UNLOCK(lowervp);
error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp,
uppervp, lowervp);
if (error) {
if (uppervp)
vput(uppervp);
if (lowervp)
vrele(lowervp);
} else {
if (*ap->a_vpp != dvp)
if (!lockparent || !(cnp->cn_flags & ISLASTCN))
VOP_UNLOCK(dvp);
}
return (error);
}
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 *un = VTOUNION(ap->a_dvp);
struct vnode *dvp = un->un_uppervp;
if (dvp) {
int error;
struct vnode *vp;
FIXUP(un);
VREF(dvp);
un->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
error = VOP_CREATE(dvp, &vp, ap->a_cnp, ap->a_vap);
if (error)
return (error);
error = union_allocvp(
ap->a_vpp,
ap->a_dvp->v_mount,
ap->a_dvp,
NULLVP,
ap->a_cnp,
vp,
NULLVP);
if (error)
vput(vp);
return (error);
}
vput(ap->a_dvp);
return (EROFS);
}
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 *un = VTOUNION(ap->a_dvp);
struct vnode *dvp = un->un_uppervp;
if (dvp) {
int error;
struct vnode *vp;
FIXUP(un);
VREF(dvp);
un->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
error = VOP_MKNOD(dvp, &vp, ap->a_cnp, ap->a_vap);
if (error)
return (error);
if (vp) {
error = union_allocvp(
ap->a_vpp,
ap->a_dvp->v_mount,
ap->a_dvp,
NULLVP,
ap->a_cnp,
vp,
NULLVP);
if (error)
vput(vp);
}
return (error);
}
vput(ap->a_dvp);
return (EROFS);
}
int
union_open(ap)
struct vop_open_args /* {
struct vnodeop_desc *a_desc;
struct vnode *a_vp;
int a_mode;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
struct union_node *un = VTOUNION(ap->a_vp);
struct vnode *tvp;
int mode = ap->a_mode;
struct ucred *cred = ap->a_cred;
struct proc *p = ap->a_p;
int error;
/*
* If there is an existing upper vp then simply open that.
*/
tvp = un->un_uppervp;
if (tvp == NULLVP) {
/*
* If the lower vnode is being opened for writing, then
* copy the file contents to the upper vnode and open that,
* otherwise can simply open the lower vnode.
*/
tvp = un->un_lowervp;
if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) {
struct vnode *vp;
int i;
/*
* Open the named file in the upper layer. Note that
* the file may have come into existence *since* the
* lookup was done, since the upper layer may really
* be a loopback mount of some other filesystem...
* so open the file with exclusive create and barf if
* it already exists.
* XXX - perhaps should re-lookup the node (once more
* with feeling) and simply open that. Who knows.
*/
error = union_vn_create(&vp, un, p);
if (error)
return (error);
/* at this point, uppervp is locked */
union_newupper(un, vp);
un->un_flags |= UN_ULOCK;
/*
* Now, if the file is being opened with truncation,
* then the (new) upper vnode is ready to fly,
* otherwise the data from the lower vnode must be
* copied to the upper layer first. This only works
* for regular files (check is made above).
*/
if ((mode & O_TRUNC) == 0) {
/*
* XXX - should not ignore errors
* from VOP_CLOSE
*/
VOP_LOCK(tvp);
error = VOP_OPEN(tvp, FREAD, cred, p);
if (error == 0) {
error = union_copyfile(p, cred,
tvp, un->un_uppervp);
VOP_UNLOCK(tvp);
(void) VOP_CLOSE(tvp, FREAD, cred, p);
} else {
VOP_UNLOCK(tvp);
}
#ifdef UNION_DIAGNOSTIC
if (!error)
uprintf("union: copied up %s\n",
un->un_path);
#endif
}
un->un_flags &= ~UN_ULOCK;
VOP_UNLOCK(un->un_uppervp);
union_vn_close(un->un_uppervp, FWRITE, cred, p);
VOP_LOCK(un->un_uppervp);
un->un_flags |= UN_ULOCK;
/*
* Subsequent IOs will go to the top layer, so
* call close on the lower vnode and open on the
* upper vnode to ensure that the filesystem keeps
* its references counts right. This doesn't do
* the right thing with (cred) and (FREAD) though.
* Ignoring error returns is not righ, either.
*/
for (i = 0; i < un->un_openl; i++) {
(void) VOP_CLOSE(tvp, FREAD, cred, p);
(void) VOP_OPEN(un->un_uppervp, FREAD, cred, p);
}
un->un_openl = 0;
if (error == 0)
error = VOP_OPEN(un->un_uppervp, mode, cred, p);
return (error);
}
/*
* Just open the lower vnode
*/
un->un_openl++;
VOP_LOCK(tvp);
error = VOP_OPEN(tvp, mode, cred, p);
VOP_UNLOCK(tvp);
return (error);
}
FIXUP(un);
error = VOP_OPEN(tvp, mode, cred, p);
return (error);
}
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 (un->un_uppervp) {
vp = un->un_uppervp;
} else {
#ifdef UNION_DIAGNOSTIC
if (un->un_openl <= 0)
panic("union: un_openl cnt");
#endif
--un->un_openl;
vp = un->un_lowervp;
}
return (VOP_CLOSE(vp, ap->a_fflag, ap->a_cred, ap->a_p));
}
/*
* 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(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);
int error = EACCES;
struct vnode *vp;
vp = un->un_uppervp;
if (vp) {
FIXUP(un);
return (VOP_ACCESS(vp, ap->a_mode, ap->a_cred, ap->a_p));
}
vp = un->un_lowervp;
if (vp) {
VOP_LOCK(vp);
error = VOP_ACCESS(vp, ap->a_mode, ap->a_cred, ap->a_p);
if (error == 0) {
struct union_mount *um = MOUNTTOUNIONMOUNT(vp->v_mount);
if (um->um_op == UNMNT_BELOW)
error = VOP_ACCESS(vp, ap->a_mode,
um->um_cred, ap->a_p);
}
VOP_UNLOCK(vp);
if (error)
return (error);
}
return (error);
}
/*
* We handle getattr only to change the fsid.
*/
int
union_getattr(ap)
struct vop_getattr_args /* {
struct vnode *a_vp;
struct vattr *a_vap;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
int error;
struct union_node *un = VTOUNION(ap->a_vp);
struct vnode *vp = un->un_uppervp;
struct vattr *vap;
struct vattr va;
/*
* Some programs walk the filesystem hierarchy by counting
* links to directories to avoid stat'ing all the time.
* This means the link count on directories needs to be "correct".
* The only way to do that is to call getattr on both layers
* and fix up the link count. The link count will not necessarily
* be accurate but will be large enough to defeat the tree walkers.
*/
vap = ap->a_vap;
vp = un->un_uppervp;
if (vp != NULLVP) {
FIXUP(un);
error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p);
if (error)
return (error);
}
if (vp == NULLVP) {
vp = un->un_lowervp;
} else if (vp->v_type == VDIR) {
vp = un->un_lowervp;
vap = &va;
} else {
vp = NULLVP;
}
if (vp != NULLVP) {
VOP_LOCK(vp);
error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p);
VOP_UNLOCK(vp);
if (error)
return (error);
}
if ((vap != ap->a_vap) && (vap->va_type == VDIR))
ap->a_vap->va_nlink += vap->va_nlink;
vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
return (0);
}
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);
int error;
/*
* 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) &&
(ap->a_vap->va_size == 0)) {
struct vnode *vp;
error = union_vn_create(&vp, un, ap->a_p);
if (error)
return (error);
/* at this point, uppervp is locked */
union_newupper(un, vp);
VOP_UNLOCK(vp);
union_vn_close(un->un_uppervp, FWRITE, ap->a_cred, ap->a_p);
VOP_LOCK(vp);
un->un_flags |= UN_ULOCK;
}
/*
* 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, ap->a_vap,
ap->a_cred, ap->a_p);
} else {
error = EROFS;
}
return (error);
}
int
union_read(ap)
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
int error;
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
VOP_LOCK(vp);
else
FIXUP(VTOUNION(ap->a_vp));
error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);
if (dolock)
VOP_UNLOCK(vp);
return (error);
}
int
union_write(ap)
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
int error;
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
VOP_LOCK(vp);
else
FIXUP(VTOUNION(ap->a_vp));
error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);
if (dolock)
VOP_UNLOCK(vp);
return (error);
}
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;
{
return (VOP_IOCTL(OTHERVP(ap->a_vp), ap->a_command, ap->a_data,
ap->a_fflag, ap->a_cred, ap->a_p));
}
int
union_select(ap)
struct vop_select_args /* {
struct vnode *a_vp;
int a_which;
int a_fflags;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
return (VOP_SELECT(OTHERVP(ap->a_vp), ap->a_which, ap->a_fflags,
ap->a_cred, ap->a_p));
}
int
union_mmap(ap)
struct vop_mmap_args /* {
struct vnode *a_vp;
int a_fflags;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
return (VOP_MMAP(OTHERVP(ap->a_vp), ap->a_fflags,
ap->a_cred, ap->a_p));
}
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 vnode *targetvp = OTHERVP(ap->a_vp);
if (targetvp) {
int dolock = (targetvp == LOWERVP(ap->a_vp));
if (dolock)
VOP_LOCK(targetvp);
else
FIXUP(VTOUNION(ap->a_vp));
error = VOP_FSYNC(targetvp, ap->a_cred,
ap->a_waitfor, ap->a_p);
if (dolock)
VOP_UNLOCK(targetvp);
}
return (error);
}
int
union_seek(ap)
struct vop_seek_args /* {
struct vnode *a_vp;
off_t a_oldoff;
off_t a_newoff;
struct ucred *a_cred;
} */ *ap;
{
return (VOP_SEEK(OTHERVP(ap->a_vp), ap->a_oldoff, ap->a_newoff, ap->a_cred));
}
int
union_remove(ap)
struct vop_remove_args /* {
struct vnode *a_dvp;
struct vnode *a_vp;
struct componentname *a_cnp;
} */ *ap;
{
int error;
struct union_node *dun = VTOUNION(ap->a_dvp);
struct union_node *un = VTOUNION(ap->a_vp);
if (dun->un_uppervp && un->un_uppervp) {
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);
error = VOP_REMOVE(dvp, vp, ap->a_cnp);
if (!error)
union_removed_upper(un);
/*
* XXX: should create a whiteout here
*/
} else {
/*
* XXX: should create a whiteout here
*/
vput(ap->a_dvp);
vput(ap->a_vp);
error = EROFS;
}
return (error);
}
int
union_link(ap)
struct vop_link_args /* {
struct vnode *a_tdvp;
struct vnode *a_vp;
struct componentname *a_cnp;
} */ *ap;
{
int error;
struct union_node *dun = VTOUNION(ap->a_vp);
struct union_node *un = VTOUNION(ap->a_tdvp);
if (dun->un_uppervp && un->un_uppervp) {
struct vnode *dvp = dun->un_uppervp;
struct vnode *vp = un->un_uppervp;
FIXUP(dun);
VREF(dvp);
dun->un_flags |= UN_KLOCK;
vput(ap->a_vp);
FIXUP(un);
VREF(vp);
vrele(ap->a_tdvp);
error = VOP_LINK(dvp, vp, ap->a_cnp);
} else {
/*
* XXX: need to copy to upper layer
* and do the link there.
*/
vput(ap->a_vp);
vrele(ap->a_tdvp);
error = EROFS;
}
return (error);
}
int
union_rename(ap)
struct vop_rename_args /* {
struct vnode *a_fdvp;
struct vnode *a_fvp;
struct componentname *a_fcnp;
struct vnode *a_tdvp;
struct vnode *a_tvp;
struct componentname *a_tcnp;
} */ *ap;
{
int error;
struct vnode *fdvp = ap->a_fdvp;
struct vnode *fvp = ap->a_fvp;
struct vnode *tdvp = ap->a_tdvp;
struct vnode *tvp = ap->a_tvp;
if (fdvp->v_op == union_vnodeop_p) { /* always true */
struct union_node *un = VTOUNION(fdvp);
if (un->un_uppervp == NULLVP) {
error = EROFS;
goto bad;
}
FIXUP(un);
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) {
error = EROFS;
goto bad;
}
FIXUP(un);
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) {
error = EROFS;
goto bad;
}
tdvp = un->un_uppervp;
VREF(tdvp);
un->un_flags |= UN_KLOCK;
vput(ap->a_tdvp);
}
if (tvp && tvp->v_op == union_vnodeop_p) {
struct union_node *un = VTOUNION(tvp);
if (un->un_uppervp == NULLVP) {
error = EROFS;
goto bad;
}
tvp = un->un_uppervp;
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)
vput(tvp);
return (error);
}
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 *un = VTOUNION(ap->a_dvp);
struct vnode *dvp = un->un_uppervp;
if (dvp) {
int error;
struct vnode *vp;
FIXUP(un);
VREF(dvp);
un->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
error = VOP_MKDIR(dvp, &vp, ap->a_cnp, ap->a_vap);
if (error)
return (error);
error = union_allocvp(
ap->a_vpp,
ap->a_dvp->v_mount,
ap->a_dvp,
NULLVP,
ap->a_cnp,
vp,
NULLVP);
if (error)
vput(vp);
return (error);
}
vput(ap->a_dvp);
return (EROFS);
}
int
union_rmdir(ap)
struct vop_rmdir_args /* {
struct vnode *a_dvp;
struct vnode *a_vp;
struct componentname *a_cnp;
} */ *ap;
{
int error;
struct union_node *dun = VTOUNION(ap->a_dvp);
struct union_node *un = VTOUNION(ap->a_vp);
if (dun->un_uppervp && un->un_uppervp) {
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);
error = VOP_RMDIR(dvp, vp, ap->a_cnp);
if (!error)
union_removed_upper(un);
/*
* XXX: should create a whiteout here
*/
} else {
/*
* XXX: should create a whiteout here
*/
vput(ap->a_dvp);
vput(ap->a_vp);
error = EROFS;
}
return (error);
}
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 *un = VTOUNION(ap->a_dvp);
struct vnode *dvp = un->un_uppervp;
if (dvp) {
int error;
struct vnode *vp;
FIXUP(un);
VREF(dvp);
un->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
error = VOP_SYMLINK(dvp, &vp, ap->a_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(ap)
struct vop_readdir_args /* {
struct vnode *a_vp;
struct uio *a_uio;
struct ucred *a_cred;
} */ *ap;
{
int error = 0;
struct union_node *un = VTOUNION(ap->a_vp);
if (un->un_uppervp) {
FIXUP(un);
error = VOP_READDIR(un->un_uppervp, ap->a_uio, ap->a_cred, NULL, NULL, NULL);
}
return (error);
}
int
union_readlink(ap)
struct vop_readlink_args /* {
struct vnode *a_vp;
struct uio *a_uio;
struct ucred *a_cred;
} */ *ap;
{
int error;
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
VOP_LOCK(vp);
else
FIXUP(VTOUNION(ap->a_vp));
error = VOP_READLINK(vp, ap->a_uio, ap->a_cred);
if (dolock)
VOP_UNLOCK(vp);
return (error);
}
int
union_abortop(ap)
struct vop_abortop_args /* {
struct vnode *a_dvp;
struct componentname *a_cnp;
} */ *ap;
{
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)
VOP_LOCK(vp);
else
FIXUP(VTOUNION(ap->a_dvp));
}
error = VOP_ABORTOP(vp, ap->a_cnp);
if (islocked && dolock)
VOP_UNLOCK(vp);
return (error);
}
int
union_inactive(ap)
struct vop_inactive_args /* {
struct vnode *a_vp;
} */ *ap;
{
/*
* 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.
*/
#ifdef UNION_DIAGNOSTIC
struct union_node *un = VTOUNION(ap->a_vp);
if (un->un_flags & UN_LOCKED)
panic("union: inactivating locked node");
#endif
return (0);
}
int
union_reclaim(ap)
struct vop_reclaim_args /* {
struct vnode *a_vp;
} */ *ap;
{
union_freevp(ap->a_vp);
return (0);
}
int
union_lock(ap)
struct vop_lock_args *ap;
{
struct vnode *vp = ap->a_vp;
struct union_node *un;
start:
while (vp->v_flag & VXLOCK) {
vp->v_flag |= VXWANT;
(void) tsleep((caddr_t)vp, PINOD, "unnlk1", 0);
}
un = VTOUNION(vp);
if (un->un_uppervp) {
if ((un->un_flags & UN_ULOCK) == 0) {
un->un_flags |= UN_ULOCK;
VOP_LOCK(un->un_uppervp);
}
#ifdef DIAGNOSTIC
if (un->un_flags & UN_KLOCK)
panic("union: dangling upper lock");
#endif
}
if (un->un_flags & UN_LOCKED) {
#ifdef DIAGNOSTIC
if (curproc && un->un_pid == curproc->p_pid &&
un->un_pid > -1 && curproc->p_pid > -1)
panic("union: locking against myself");
#endif
un->un_flags |= UN_WANT;
(void) tsleep((caddr_t) &un->un_flags, PINOD, "unnlk2", 0);
goto start;
}
#ifdef DIAGNOSTIC
if (curproc)
un->un_pid = curproc->p_pid;
else
un->un_pid = -1;
#endif
un->un_flags |= UN_LOCKED;
return (0);
}
int
union_unlock(ap)
struct vop_lock_args *ap;
{
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");
#endif
un->un_flags &= ~UN_LOCKED;
if ((un->un_flags & (UN_ULOCK|UN_KLOCK)) == UN_ULOCK)
VOP_UNLOCK(un->un_uppervp);
un->un_flags &= ~(UN_ULOCK|UN_KLOCK);
if (un->un_flags & UN_WANT) {
un->un_flags &= ~UN_WANT;
wakeup((caddr_t) &un->un_flags);
}
#ifdef DIAGNOSTIC
un->un_pid = 0;
#endif
return (0);
}
int
union_bmap(ap)
struct vop_bmap_args /* {
struct vnode *a_vp;
daddr_t a_bn;
struct vnode **a_vpp;
daddr_t *a_bnp;
int *a_runp;
int *a_runb;
} */ *ap;
{
int error;
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
VOP_LOCK(vp);
else
FIXUP(VTOUNION(ap->a_vp));
error = VOP_BMAP(vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp, ap->a_runb);
if (dolock)
VOP_UNLOCK(vp);
return (error);
}
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));
return (0);
}
int
union_islocked(ap)
struct vop_islocked_args /* {
struct vnode *a_vp;
} */ *ap;
{
return ((VTOUNION(ap->a_vp)->un_flags & UN_LOCKED) ? 1 : 0);
}
int
union_pathconf(ap)
struct vop_pathconf_args /* {
struct vnode *a_vp;
int a_name;
int *a_retval;
} */ *ap;
{
int error;
struct vnode *vp = OTHERVP(ap->a_vp);
int dolock = (vp == LOWERVP(ap->a_vp));
if (dolock)
VOP_LOCK(vp);
else
FIXUP(VTOUNION(ap->a_vp));
error = VOP_PATHCONF(vp, ap->a_name, ap->a_retval);
if (dolock)
VOP_UNLOCK(vp);
return (error);
}
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;
{
return (VOP_ADVLOCK(OTHERVP(ap->a_vp), ap->a_id, ap->a_op,
ap->a_fl, ap->a_flags));
}
/*
* 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(ap)
struct vop_strategy_args /* {
struct buf *a_bp;
} */ *ap;
{
struct buf *bp = ap->a_bp;
int error;
struct vnode *savedvp;
savedvp = bp->b_vp;
bp->b_vp = OTHERVP(bp->b_vp);
#ifdef DIAGNOSTIC
if (bp->b_vp == NULLVP)
panic("union_strategy: nil vp");
if (((bp->b_flags & B_READ) == 0) &&
(bp->b_vp == LOWERVP(savedvp)))
panic("union_strategy: writing to lowervp");
#endif
error = VOP_STRATEGY(bp);
bp->b_vp = savedvp;
return (error);
}
/*
* Global vfs data structures
*/
vop_t **union_vnodeop_p;
struct vnodeopv_entry_desc union_vnodeop_entries[] = {
{ &vop_default_desc, (vop_t *)vn_default_error },
{ &vop_lookup_desc, (vop_t *)union_lookup }, /* lookup */
{ &vop_create_desc, (vop_t *)union_create }, /* create */
{ &vop_mknod_desc, (vop_t *)union_mknod }, /* mknod */
{ &vop_open_desc, (vop_t *)union_open }, /* open */
{ &vop_close_desc, (vop_t *)union_close }, /* close */
{ &vop_access_desc, (vop_t *)union_access }, /* access */
{ &vop_getattr_desc, (vop_t *)union_getattr }, /* getattr */
{ &vop_setattr_desc, (vop_t *)union_setattr }, /* setattr */
{ &vop_read_desc, (vop_t *)union_read }, /* read */
{ &vop_write_desc, (vop_t *)union_write }, /* write */
{ &vop_ioctl_desc, (vop_t *)union_ioctl }, /* ioctl */
{ &vop_select_desc, (vop_t *)union_select }, /* select */
{ &vop_mmap_desc, (vop_t *)union_mmap }, /* mmap */
{ &vop_fsync_desc, (vop_t *)union_fsync }, /* fsync */
{ &vop_seek_desc, (vop_t *)union_seek }, /* seek */
{ &vop_remove_desc, (vop_t *)union_remove }, /* remove */
{ &vop_link_desc, (vop_t *)union_link }, /* link */
{ &vop_rename_desc, (vop_t *)union_rename }, /* rename */
{ &vop_mkdir_desc, (vop_t *)union_mkdir }, /* mkdir */
{ &vop_rmdir_desc, (vop_t *)union_rmdir }, /* rmdir */
{ &vop_symlink_desc, (vop_t *)union_symlink }, /* symlink */
{ &vop_readdir_desc, (vop_t *)union_readdir }, /* readdir */
{ &vop_readlink_desc, (vop_t *)union_readlink }, /* readlink */
{ &vop_abortop_desc, (vop_t *)union_abortop }, /* abortop */
{ &vop_inactive_desc, (vop_t *)union_inactive }, /* inactive */
{ &vop_reclaim_desc, (vop_t *)union_reclaim }, /* reclaim */
{ &vop_lock_desc, (vop_t *)union_lock }, /* lock */
{ &vop_unlock_desc, (vop_t *)union_unlock }, /* unlock */
{ &vop_bmap_desc, (vop_t *)union_bmap }, /* bmap */
{ &vop_strategy_desc, (vop_t *)union_strategy }, /* strategy */
{ &vop_print_desc, (vop_t *)union_print }, /* print */
{ &vop_islocked_desc, (vop_t *)union_islocked }, /* islocked */
{ &vop_pathconf_desc, (vop_t *)union_pathconf }, /* pathconf */
{ &vop_advlock_desc, (vop_t *)union_advlock }, /* advlock */
#ifdef notdef
{ &vop_blkatoff_desc, (vop_t *)union_blkatoff }, /* blkatoff */
{ &vop_valloc_desc, (vop_t *)union_valloc }, /* valloc */
{ &vop_vfree_desc, (vop_t *)union_vfree }, /* vfree */
{ &vop_truncate_desc, (vop_t *)union_truncate }, /* truncate */
{ &vop_update_desc, (vop_t *)union_update }, /* update */
{ &vop_bwrite_desc, (vop_t *)union_bwrite }, /* bwrite */
#endif
{ NULL, NULL }
};
struct vnodeopv_desc union_vnodeop_opv_desc =
{ &union_vnodeop_p, union_vnodeop_entries };
VNODEOP_SET(union_vnodeop_opv_desc);