1156 lines
26 KiB
C
1156 lines
26 KiB
C
/* $NetBSD: union_subr.c,v 1.41 2001/11/10 13:33:45 lukem Exp $ */
|
|
|
|
/*
|
|
* Copyright (c) 1994 Jan-Simon Pendry
|
|
* Copyright (c) 1994
|
|
* 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_subr.c 8.20 (Berkeley) 5/20/95
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__KERNEL_RCSID(0, "$NetBSD: union_subr.c,v 1.41 2001/11/10 13:33:45 lukem Exp $");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/time.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/vnode.h>
|
|
#include <sys/namei.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/file.h>
|
|
#include <sys/filedesc.h>
|
|
#include <sys/queue.h>
|
|
#include <sys/mount.h>
|
|
#include <sys/stat.h>
|
|
|
|
#include <uvm/uvm_extern.h>
|
|
|
|
#include <miscfs/union/union.h>
|
|
|
|
#ifdef DIAGNOSTIC
|
|
#include <sys/proc.h>
|
|
#endif
|
|
|
|
/* must be power of two, otherwise change UNION_HASH() */
|
|
#define NHASH 32
|
|
|
|
/* unsigned int ... */
|
|
#define UNION_HASH(u, l) \
|
|
(((((unsigned long) (u)) + ((unsigned long) l)) >> 8) & (NHASH-1))
|
|
|
|
static LIST_HEAD(unhead, union_node) unhead[NHASH];
|
|
static int unvplock[NHASH];
|
|
|
|
static int union_list_lock __P((int));
|
|
static void union_list_unlock __P((int));
|
|
void union_updatevp __P((struct union_node *, struct vnode *, struct vnode *));
|
|
static int union_relookup __P((struct union_mount *, struct vnode *,
|
|
struct vnode **, struct componentname *,
|
|
struct componentname *, const char *, int));
|
|
int union_vn_close __P((struct vnode *, int, struct ucred *, struct proc *));
|
|
static void union_dircache_r __P((struct vnode *, struct vnode ***, int *));
|
|
struct vnode *union_dircache __P((struct vnode *, struct proc *));
|
|
|
|
void
|
|
union_init()
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < NHASH; i++)
|
|
LIST_INIT(&unhead[i]);
|
|
memset((caddr_t) unvplock, 0, sizeof(unvplock));
|
|
}
|
|
|
|
/*
|
|
* Free global unionfs resources.
|
|
*/
|
|
void
|
|
union_done()
|
|
{
|
|
/* Nothing */
|
|
}
|
|
|
|
static int
|
|
union_list_lock(ix)
|
|
int ix;
|
|
{
|
|
|
|
if (unvplock[ix] & UN_LOCKED) {
|
|
unvplock[ix] |= UN_WANTED;
|
|
(void) tsleep(&unvplock[ix], PINOD, "unionlk", 0);
|
|
return (1);
|
|
}
|
|
|
|
unvplock[ix] |= UN_LOCKED;
|
|
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
union_list_unlock(ix)
|
|
int ix;
|
|
{
|
|
|
|
unvplock[ix] &= ~UN_LOCKED;
|
|
|
|
if (unvplock[ix] & UN_WANTED) {
|
|
unvplock[ix] &= ~UN_WANTED;
|
|
wakeup((caddr_t) &unvplock[ix]);
|
|
}
|
|
}
|
|
|
|
void
|
|
union_updatevp(un, uppervp, lowervp)
|
|
struct union_node *un;
|
|
struct vnode *uppervp;
|
|
struct vnode *lowervp;
|
|
{
|
|
int ohash = UNION_HASH(un->un_uppervp, un->un_lowervp);
|
|
int nhash = UNION_HASH(uppervp, lowervp);
|
|
int docache = (lowervp != NULLVP || uppervp != NULLVP);
|
|
int lhash, uhash;
|
|
|
|
/*
|
|
* Ensure locking is ordered from lower to higher
|
|
* to avoid deadlocks.
|
|
*/
|
|
if (nhash < ohash) {
|
|
lhash = nhash;
|
|
uhash = ohash;
|
|
} else {
|
|
lhash = ohash;
|
|
uhash = nhash;
|
|
}
|
|
|
|
if (lhash != uhash)
|
|
while (union_list_lock(lhash))
|
|
continue;
|
|
|
|
while (union_list_lock(uhash))
|
|
continue;
|
|
|
|
if (ohash != nhash || !docache) {
|
|
if (un->un_flags & UN_CACHED) {
|
|
un->un_flags &= ~UN_CACHED;
|
|
LIST_REMOVE(un, un_cache);
|
|
}
|
|
}
|
|
|
|
if (ohash != nhash)
|
|
union_list_unlock(ohash);
|
|
|
|
if (un->un_lowervp != lowervp) {
|
|
if (un->un_lowervp) {
|
|
vrele(un->un_lowervp);
|
|
if (un->un_path) {
|
|
free(un->un_path, M_TEMP);
|
|
un->un_path = 0;
|
|
}
|
|
if (un->un_dirvp) {
|
|
vrele(un->un_dirvp);
|
|
un->un_dirvp = NULLVP;
|
|
}
|
|
}
|
|
un->un_lowervp = lowervp;
|
|
un->un_lowersz = VNOVAL;
|
|
}
|
|
|
|
if (un->un_uppervp != uppervp) {
|
|
if (un->un_uppervp)
|
|
vrele(un->un_uppervp);
|
|
|
|
un->un_uppervp = uppervp;
|
|
un->un_uppersz = VNOVAL;
|
|
}
|
|
|
|
if (docache && (ohash != nhash)) {
|
|
LIST_INSERT_HEAD(&unhead[nhash], un, un_cache);
|
|
un->un_flags |= UN_CACHED;
|
|
}
|
|
|
|
union_list_unlock(nhash);
|
|
}
|
|
|
|
void
|
|
union_newlower(un, lowervp)
|
|
struct union_node *un;
|
|
struct vnode *lowervp;
|
|
{
|
|
|
|
union_updatevp(un, un->un_uppervp, lowervp);
|
|
}
|
|
|
|
void
|
|
union_newupper(un, uppervp)
|
|
struct union_node *un;
|
|
struct vnode *uppervp;
|
|
{
|
|
|
|
union_updatevp(un, uppervp, un->un_lowervp);
|
|
}
|
|
|
|
/*
|
|
* Keep track of size changes in the underlying vnodes.
|
|
* If the size changes, then callback to the vm layer
|
|
* giving priority to the upper layer size.
|
|
*/
|
|
void
|
|
union_newsize(vp, uppersz, lowersz)
|
|
struct vnode *vp;
|
|
off_t uppersz, lowersz;
|
|
{
|
|
struct union_node *un;
|
|
off_t sz;
|
|
|
|
/* only interested in regular files */
|
|
if (vp->v_type != VREG)
|
|
return;
|
|
|
|
un = VTOUNION(vp);
|
|
sz = VNOVAL;
|
|
|
|
if ((uppersz != VNOVAL) && (un->un_uppersz != uppersz)) {
|
|
un->un_uppersz = uppersz;
|
|
if (sz == VNOVAL)
|
|
sz = un->un_uppersz;
|
|
}
|
|
|
|
if ((lowersz != VNOVAL) && (un->un_lowersz != lowersz)) {
|
|
un->un_lowersz = lowersz;
|
|
if (sz == VNOVAL)
|
|
sz = un->un_lowersz;
|
|
}
|
|
|
|
if (sz != VNOVAL) {
|
|
#ifdef UNION_DIAGNOSTIC
|
|
printf("union: %s size now %qd\n",
|
|
uppersz != VNOVAL ? "upper" : "lower", sz);
|
|
#endif
|
|
uvm_vnp_setsize(vp, sz);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* allocate a union_node/vnode pair. the vnode is
|
|
* referenced and locked. the new vnode is returned
|
|
* via (vpp). (mp) is the mountpoint of the union filesystem,
|
|
* (dvp) is the parent directory where the upper layer object
|
|
* should exist (but doesn't) and (cnp) is the componentname
|
|
* information which is partially copied to allow the upper
|
|
* layer object to be created at a later time. (uppervp)
|
|
* and (lowervp) reference the upper and lower layer objects
|
|
* being mapped. either, but not both, can be nil.
|
|
* if supplied, (uppervp) is locked.
|
|
* the reference is either maintained in the new union_node
|
|
* object which is allocated, or they are vrele'd.
|
|
*
|
|
* all union_nodes are maintained on a singly-linked
|
|
* list. new nodes are only allocated when they cannot
|
|
* be found on this list. entries on the list are
|
|
* removed when the vfs reclaim entry is called.
|
|
*
|
|
* a single lock is kept for the entire list. this is
|
|
* needed because the getnewvnode() function can block
|
|
* waiting for a vnode to become free, in which case there
|
|
* may be more than one process trying to get the same
|
|
* vnode. this lock is only taken if we are going to
|
|
* call getnewvnode, since the kernel itself is single-threaded.
|
|
*
|
|
* if an entry is found on the list, then call vget() to
|
|
* take a reference. this is done because there may be
|
|
* zero references to it and so it needs to removed from
|
|
* the vnode free list.
|
|
*/
|
|
int
|
|
union_allocvp(vpp, mp, undvp, dvp, cnp, uppervp, lowervp, docache)
|
|
struct vnode **vpp;
|
|
struct mount *mp;
|
|
struct vnode *undvp; /* parent union vnode */
|
|
struct vnode *dvp; /* may be null */
|
|
struct componentname *cnp; /* may be null */
|
|
struct vnode *uppervp; /* may be null */
|
|
struct vnode *lowervp; /* may be null */
|
|
int docache;
|
|
{
|
|
int error;
|
|
struct union_node *un = NULL;
|
|
struct vnode *xlowervp = NULLVP;
|
|
struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
|
|
int hash = 0;
|
|
int vflag;
|
|
int try;
|
|
|
|
if (uppervp == NULLVP && lowervp == NULLVP)
|
|
panic("union: unidentifiable allocation");
|
|
|
|
if (uppervp && lowervp && (uppervp->v_type != lowervp->v_type)) {
|
|
xlowervp = lowervp;
|
|
lowervp = NULLVP;
|
|
}
|
|
|
|
/* detect the root vnode (and aliases) */
|
|
vflag = VLAYER;
|
|
if ((uppervp == um->um_uppervp) &&
|
|
((lowervp == NULLVP) || lowervp == um->um_lowervp)) {
|
|
if (lowervp == NULLVP) {
|
|
lowervp = um->um_lowervp;
|
|
if (lowervp != NULLVP)
|
|
VREF(lowervp);
|
|
}
|
|
vflag = VROOT;
|
|
}
|
|
|
|
loop:
|
|
if (!docache) {
|
|
un = 0;
|
|
} else for (try = 0; try < 3; try++) {
|
|
switch (try) {
|
|
case 0:
|
|
if (lowervp == NULLVP)
|
|
continue;
|
|
hash = UNION_HASH(uppervp, lowervp);
|
|
break;
|
|
|
|
case 1:
|
|
if (uppervp == NULLVP)
|
|
continue;
|
|
hash = UNION_HASH(uppervp, NULLVP);
|
|
break;
|
|
|
|
case 2:
|
|
if (lowervp == NULLVP)
|
|
continue;
|
|
hash = UNION_HASH(NULLVP, lowervp);
|
|
break;
|
|
}
|
|
|
|
while (union_list_lock(hash))
|
|
continue;
|
|
|
|
for (un = unhead[hash].lh_first; un != 0;
|
|
un = un->un_cache.le_next) {
|
|
if ((un->un_lowervp == lowervp ||
|
|
un->un_lowervp == NULLVP) &&
|
|
(un->un_uppervp == uppervp ||
|
|
un->un_uppervp == NULLVP) &&
|
|
(UNIONTOV(un)->v_mount == mp)) {
|
|
if (vget(UNIONTOV(un), 0)) {
|
|
union_list_unlock(hash);
|
|
goto loop;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
union_list_unlock(hash);
|
|
|
|
if (un)
|
|
break;
|
|
}
|
|
|
|
if (un) {
|
|
/*
|
|
* Obtain a lock on the union_node.
|
|
* uppervp is locked, though un->un_uppervp
|
|
* may not be. this doesn't break the locking
|
|
* hierarchy since in the case that un->un_uppervp
|
|
* is not yet locked it will be vrele'd and replaced
|
|
* with uppervp.
|
|
*/
|
|
|
|
if ((dvp != NULLVP) && (uppervp == dvp)) {
|
|
/*
|
|
* Access ``.'', so (un) will already
|
|
* be locked. Since this process has
|
|
* the lock on (uppervp) no other
|
|
* process can hold the lock on (un).
|
|
*/
|
|
#ifdef DIAGNOSTIC
|
|
if ((un->un_flags & UN_LOCKED) == 0)
|
|
panic("union: . not locked");
|
|
else if (curproc && un->un_pid != curproc->p_pid &&
|
|
un->un_pid > -1 && curproc->p_pid > -1)
|
|
panic("union: allocvp not lock owner");
|
|
#endif
|
|
} else {
|
|
if (un->un_flags & UN_LOCKED) {
|
|
vrele(UNIONTOV(un));
|
|
un->un_flags |= UN_WANTED;
|
|
(void) tsleep(&un->un_flags, PINOD,
|
|
"unionalloc", 0);
|
|
goto loop;
|
|
}
|
|
un->un_flags |= UN_LOCKED;
|
|
|
|
#ifdef DIAGNOSTIC
|
|
if (curproc)
|
|
un->un_pid = curproc->p_pid;
|
|
else
|
|
un->un_pid = -1;
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* At this point, the union_node is locked,
|
|
* un->un_uppervp may not be locked, and uppervp
|
|
* is locked or nil.
|
|
*/
|
|
|
|
/*
|
|
* Save information about the upper layer.
|
|
*/
|
|
if (uppervp != un->un_uppervp) {
|
|
union_newupper(un, uppervp);
|
|
} else if (uppervp) {
|
|
vrele(uppervp);
|
|
}
|
|
|
|
if (un->un_uppervp) {
|
|
un->un_flags |= UN_ULOCK;
|
|
un->un_flags &= ~UN_KLOCK;
|
|
}
|
|
|
|
/*
|
|
* Save information about the lower layer.
|
|
* This needs to keep track of pathname
|
|
* and directory information which union_vn_create
|
|
* might need.
|
|
*/
|
|
if (lowervp != un->un_lowervp) {
|
|
union_newlower(un, lowervp);
|
|
if (cnp && (lowervp != NULLVP)) {
|
|
un->un_hash = cnp->cn_hash;
|
|
un->un_path = malloc(cnp->cn_namelen+1,
|
|
M_TEMP, M_WAITOK);
|
|
memcpy(un->un_path, cnp->cn_nameptr,
|
|
cnp->cn_namelen);
|
|
un->un_path[cnp->cn_namelen] = '\0';
|
|
VREF(dvp);
|
|
un->un_dirvp = dvp;
|
|
}
|
|
} else if (lowervp) {
|
|
vrele(lowervp);
|
|
}
|
|
*vpp = UNIONTOV(un);
|
|
return (0);
|
|
}
|
|
|
|
if (docache) {
|
|
/*
|
|
* otherwise lock the vp list while we call getnewvnode
|
|
* since that can block.
|
|
*/
|
|
hash = UNION_HASH(uppervp, lowervp);
|
|
|
|
if (union_list_lock(hash))
|
|
goto loop;
|
|
}
|
|
|
|
error = getnewvnode(VT_UNION, mp, union_vnodeop_p, vpp);
|
|
if (error) {
|
|
if (uppervp) {
|
|
if (dvp == uppervp)
|
|
vrele(uppervp);
|
|
else
|
|
vput(uppervp);
|
|
}
|
|
if (lowervp)
|
|
vrele(lowervp);
|
|
|
|
goto out;
|
|
}
|
|
|
|
MALLOC((*vpp)->v_data, void *, sizeof(struct union_node),
|
|
M_TEMP, M_WAITOK);
|
|
|
|
(*vpp)->v_flag |= vflag;
|
|
(*vpp)->v_vnlock = NULL; /* Make upper layers call VOP_LOCK */
|
|
if (uppervp)
|
|
(*vpp)->v_type = uppervp->v_type;
|
|
else
|
|
(*vpp)->v_type = lowervp->v_type;
|
|
un = VTOUNION(*vpp);
|
|
un->un_vnode = *vpp;
|
|
un->un_uppervp = uppervp;
|
|
un->un_uppersz = VNOVAL;
|
|
un->un_lowervp = lowervp;
|
|
un->un_lowersz = VNOVAL;
|
|
un->un_pvp = undvp;
|
|
if (undvp != NULLVP)
|
|
VREF(undvp);
|
|
un->un_dircache = 0;
|
|
un->un_openl = 0;
|
|
un->un_flags = UN_LOCKED;
|
|
if (un->un_uppervp)
|
|
un->un_flags |= UN_ULOCK;
|
|
#ifdef DIAGNOSTIC
|
|
if (curproc)
|
|
un->un_pid = curproc->p_pid;
|
|
else
|
|
un->un_pid = -1;
|
|
#endif
|
|
if (cnp && (lowervp != NULLVP)) {
|
|
un->un_hash = cnp->cn_hash;
|
|
un->un_path = malloc(cnp->cn_namelen+1, M_TEMP, M_WAITOK);
|
|
memcpy(un->un_path, cnp->cn_nameptr, cnp->cn_namelen);
|
|
un->un_path[cnp->cn_namelen] = '\0';
|
|
VREF(dvp);
|
|
un->un_dirvp = dvp;
|
|
} else {
|
|
un->un_hash = 0;
|
|
un->un_path = 0;
|
|
un->un_dirvp = 0;
|
|
}
|
|
|
|
if (docache) {
|
|
LIST_INSERT_HEAD(&unhead[hash], un, un_cache);
|
|
un->un_flags |= UN_CACHED;
|
|
}
|
|
|
|
if (xlowervp)
|
|
vrele(xlowervp);
|
|
|
|
out:
|
|
if (docache)
|
|
union_list_unlock(hash);
|
|
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
union_freevp(vp)
|
|
struct vnode *vp;
|
|
{
|
|
struct union_node *un = VTOUNION(vp);
|
|
|
|
if (un->un_flags & UN_CACHED) {
|
|
un->un_flags &= ~UN_CACHED;
|
|
LIST_REMOVE(un, un_cache);
|
|
}
|
|
|
|
if (un->un_pvp != NULLVP)
|
|
vrele(un->un_pvp);
|
|
if (un->un_uppervp != NULLVP)
|
|
vrele(un->un_uppervp);
|
|
if (un->un_lowervp != NULLVP)
|
|
vrele(un->un_lowervp);
|
|
if (un->un_dirvp != NULLVP)
|
|
vrele(un->un_dirvp);
|
|
if (un->un_path)
|
|
free(un->un_path, M_TEMP);
|
|
|
|
FREE(vp->v_data, M_TEMP);
|
|
vp->v_data = 0;
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* copyfile. copy the vnode (fvp) to the vnode (tvp)
|
|
* using a sequence of reads and writes. both (fvp)
|
|
* and (tvp) are locked on entry and exit.
|
|
*/
|
|
int
|
|
union_copyfile(fvp, tvp, cred, p)
|
|
struct vnode *fvp;
|
|
struct vnode *tvp;
|
|
struct ucred *cred;
|
|
struct proc *p;
|
|
{
|
|
char *buf;
|
|
struct uio uio;
|
|
struct iovec iov;
|
|
int error = 0;
|
|
|
|
/*
|
|
* strategy:
|
|
* allocate a buffer of size MAXBSIZE.
|
|
* loop doing reads and writes, keeping track
|
|
* of the current uio offset.
|
|
* give up at the first sign of trouble.
|
|
*/
|
|
|
|
uio.uio_procp = p;
|
|
uio.uio_segflg = UIO_SYSSPACE;
|
|
uio.uio_offset = 0;
|
|
|
|
VOP_UNLOCK(fvp, 0); /* XXX */
|
|
VOP_LEASE(fvp, p, cred, LEASE_READ);
|
|
vn_lock(fvp, LK_EXCLUSIVE | LK_RETRY); /* XXX */
|
|
VOP_UNLOCK(tvp, 0); /* XXX */
|
|
VOP_LEASE(tvp, p, cred, LEASE_WRITE);
|
|
vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY); /* XXX */
|
|
|
|
buf = malloc(MAXBSIZE, M_TEMP, M_WAITOK);
|
|
|
|
/* ugly loop follows... */
|
|
do {
|
|
off_t offset = uio.uio_offset;
|
|
|
|
uio.uio_iov = &iov;
|
|
uio.uio_iovcnt = 1;
|
|
iov.iov_base = buf;
|
|
iov.iov_len = MAXBSIZE;
|
|
uio.uio_resid = iov.iov_len;
|
|
uio.uio_rw = UIO_READ;
|
|
error = VOP_READ(fvp, &uio, 0, cred);
|
|
|
|
if (error == 0) {
|
|
uio.uio_iov = &iov;
|
|
uio.uio_iovcnt = 1;
|
|
iov.iov_base = buf;
|
|
iov.iov_len = MAXBSIZE - uio.uio_resid;
|
|
uio.uio_offset = offset;
|
|
uio.uio_rw = UIO_WRITE;
|
|
uio.uio_resid = iov.iov_len;
|
|
|
|
if (uio.uio_resid == 0)
|
|
break;
|
|
|
|
do {
|
|
error = VOP_WRITE(tvp, &uio, 0, cred);
|
|
} while ((uio.uio_resid > 0) && (error == 0));
|
|
}
|
|
|
|
} while (error == 0);
|
|
|
|
free(buf, M_TEMP);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* (un) is assumed to be locked on entry and remains
|
|
* locked on exit.
|
|
*/
|
|
int
|
|
union_copyup(un, docopy, cred, p)
|
|
struct union_node *un;
|
|
int docopy;
|
|
struct ucred *cred;
|
|
struct proc *p;
|
|
{
|
|
int error;
|
|
struct vnode *lvp, *uvp;
|
|
struct vattr lvattr, uvattr;
|
|
|
|
error = union_vn_create(&uvp, un, p);
|
|
if (error)
|
|
return (error);
|
|
|
|
/* at this point, uppervp is locked */
|
|
union_newupper(un, uvp);
|
|
un->un_flags |= UN_ULOCK;
|
|
|
|
lvp = un->un_lowervp;
|
|
|
|
if (docopy) {
|
|
/*
|
|
* XX - should not ignore errors
|
|
* from VOP_CLOSE
|
|
*/
|
|
vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY);
|
|
|
|
error = VOP_GETATTR(lvp, &lvattr, cred, p);
|
|
if (error == 0)
|
|
error = VOP_OPEN(lvp, FREAD, cred, p);
|
|
if (error == 0) {
|
|
error = union_copyfile(lvp, uvp, cred, p);
|
|
(void) VOP_CLOSE(lvp, FREAD, cred, p);
|
|
}
|
|
if (error == 0) {
|
|
/* Copy permissions up too */
|
|
VATTR_NULL(&uvattr);
|
|
uvattr.va_mode = lvattr.va_mode;
|
|
uvattr.va_flags = lvattr.va_flags;
|
|
error = VOP_SETATTR(uvp, &uvattr, cred, p);
|
|
}
|
|
VOP_UNLOCK(lvp, 0);
|
|
#ifdef UNION_DIAGNOSTIC
|
|
if (error == 0)
|
|
uprintf("union: copied up %s\n", un->un_path);
|
|
#endif
|
|
|
|
}
|
|
union_vn_close(uvp, FWRITE, cred, p);
|
|
|
|
/*
|
|
* 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 right, either.
|
|
*/
|
|
if (error == 0) {
|
|
int i;
|
|
|
|
vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY);
|
|
for (i = 0; i < un->un_openl; i++) {
|
|
(void) VOP_CLOSE(lvp, FREAD, cred, p);
|
|
(void) VOP_OPEN(uvp, FREAD, cred, p);
|
|
}
|
|
un->un_openl = 0;
|
|
VOP_UNLOCK(lvp, 0);
|
|
}
|
|
|
|
return (error);
|
|
|
|
}
|
|
|
|
static int
|
|
union_relookup(um, dvp, vpp, cnp, cn, path, pathlen)
|
|
struct union_mount *um;
|
|
struct vnode *dvp;
|
|
struct vnode **vpp;
|
|
struct componentname *cnp;
|
|
struct componentname *cn;
|
|
const char *path;
|
|
int pathlen;
|
|
{
|
|
int error;
|
|
|
|
/*
|
|
* A new componentname structure must be faked up because
|
|
* there is no way to know where the upper level cnp came
|
|
* from or what it is being used for. This must duplicate
|
|
* some of the work done by NDINIT, some of the work done
|
|
* by namei, some of the work done by lookup and some of
|
|
* the work done by VOP_LOOKUP when given a CREATE flag.
|
|
* Conclusion: Horrible.
|
|
*
|
|
* The pathname buffer will be PNBUF_PUT'd by VOP_MKDIR.
|
|
*/
|
|
cn->cn_namelen = pathlen;
|
|
if ((cn->cn_namelen + 1) > MAXPATHLEN)
|
|
return (ENAMETOOLONG);
|
|
cn->cn_pnbuf = PNBUF_GET();
|
|
memcpy(cn->cn_pnbuf, path, cn->cn_namelen);
|
|
cn->cn_pnbuf[cn->cn_namelen] = '\0';
|
|
|
|
cn->cn_nameiop = CREATE;
|
|
cn->cn_flags = (LOCKPARENT|HASBUF|SAVENAME|SAVESTART|ISLASTCN);
|
|
cn->cn_proc = cnp->cn_proc;
|
|
if (um->um_op == UNMNT_ABOVE)
|
|
cn->cn_cred = cnp->cn_cred;
|
|
else
|
|
cn->cn_cred = um->um_cred;
|
|
cn->cn_nameptr = cn->cn_pnbuf;
|
|
cn->cn_hash = cnp->cn_hash;
|
|
cn->cn_consume = cnp->cn_consume;
|
|
|
|
VREF(dvp);
|
|
error = relookup(dvp, vpp, cn);
|
|
if (!error)
|
|
vrele(dvp);
|
|
else {
|
|
PNBUF_PUT(cn->cn_pnbuf);
|
|
cn->cn_pnbuf = 0;
|
|
}
|
|
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Create a shadow directory in the upper layer.
|
|
* The new vnode is returned locked.
|
|
*
|
|
* (um) points to the union mount structure for access to the
|
|
* the mounting process's credentials.
|
|
* (dvp) is the directory in which to create the shadow directory.
|
|
* it is unlocked on entry and exit.
|
|
* (cnp) is the componentname to be created.
|
|
* (vpp) is the returned newly created shadow directory, which
|
|
* is returned locked.
|
|
*
|
|
* N.B. We still attempt to create shadow directories even if the union
|
|
* is mounted read-only, which is a little nonintuitive.
|
|
*/
|
|
int
|
|
union_mkshadow(um, dvp, cnp, vpp)
|
|
struct union_mount *um;
|
|
struct vnode *dvp;
|
|
struct componentname *cnp;
|
|
struct vnode **vpp;
|
|
{
|
|
int error;
|
|
struct vattr va;
|
|
struct proc *p = cnp->cn_proc;
|
|
struct componentname cn;
|
|
|
|
error = union_relookup(um, dvp, vpp, cnp, &cn,
|
|
cnp->cn_nameptr, cnp->cn_namelen);
|
|
if (error)
|
|
return (error);
|
|
|
|
if (*vpp) {
|
|
VOP_ABORTOP(dvp, &cn);
|
|
VOP_UNLOCK(dvp, 0);
|
|
vrele(*vpp);
|
|
*vpp = NULLVP;
|
|
return (EEXIST);
|
|
}
|
|
|
|
/*
|
|
* policy: when creating the shadow directory in the
|
|
* upper layer, create it owned by the user who did
|
|
* the mount, group from parent directory, and mode
|
|
* 777 modified by umask (ie mostly identical to the
|
|
* mkdir syscall). (jsp, kb)
|
|
*/
|
|
|
|
VATTR_NULL(&va);
|
|
va.va_type = VDIR;
|
|
va.va_mode = um->um_cmode;
|
|
|
|
/* VOP_LEASE: dvp is locked */
|
|
VOP_LEASE(dvp, p, cn.cn_cred, LEASE_WRITE);
|
|
|
|
error = VOP_MKDIR(dvp, vpp, &cn, &va);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Create a whiteout entry in the upper layer.
|
|
*
|
|
* (um) points to the union mount structure for access to the
|
|
* the mounting process's credentials.
|
|
* (dvp) is the directory in which to create the whiteout.
|
|
* it is locked on entry and exit.
|
|
* (cnp) is the componentname to be created.
|
|
*/
|
|
int
|
|
union_mkwhiteout(um, dvp, cnp, path)
|
|
struct union_mount *um;
|
|
struct vnode *dvp;
|
|
struct componentname *cnp;
|
|
char *path;
|
|
{
|
|
int error;
|
|
struct proc *p = cnp->cn_proc;
|
|
struct vnode *wvp;
|
|
struct componentname cn;
|
|
|
|
VOP_UNLOCK(dvp, 0);
|
|
error = union_relookup(um, dvp, &wvp, cnp, &cn, path, strlen(path));
|
|
if (error) {
|
|
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
|
|
return (error);
|
|
}
|
|
|
|
if (wvp) {
|
|
VOP_ABORTOP(dvp, &cn);
|
|
vrele(dvp);
|
|
vrele(wvp);
|
|
return (EEXIST);
|
|
}
|
|
|
|
/* VOP_LEASE: dvp is locked */
|
|
VOP_LEASE(dvp, p, p->p_ucred, LEASE_WRITE);
|
|
|
|
error = VOP_WHITEOUT(dvp, &cn, CREATE);
|
|
if (error)
|
|
VOP_ABORTOP(dvp, &cn);
|
|
|
|
vrele(dvp);
|
|
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* union_vn_create: creates and opens a new shadow file
|
|
* on the upper union layer. this function is similar
|
|
* in spirit to calling vn_open but it avoids calling namei().
|
|
* the problem with calling namei is that a) it locks too many
|
|
* things, and b) it doesn't start at the "right" directory,
|
|
* whereas relookup is told where to start.
|
|
*/
|
|
int
|
|
union_vn_create(vpp, un, p)
|
|
struct vnode **vpp;
|
|
struct union_node *un;
|
|
struct proc *p;
|
|
{
|
|
struct vnode *vp;
|
|
struct ucred *cred = p->p_ucred;
|
|
struct vattr vat;
|
|
struct vattr *vap = &vat;
|
|
int fmode = FFLAGS(O_WRONLY|O_CREAT|O_TRUNC|O_EXCL);
|
|
int error;
|
|
int cmode = UN_FILEMODE & ~p->p_cwdi->cwdi_cmask;
|
|
struct componentname cn;
|
|
|
|
*vpp = NULLVP;
|
|
|
|
/*
|
|
* Build a new componentname structure (for the same
|
|
* reasons outlines in union_mkshadow).
|
|
* The difference here is that the file is owned by
|
|
* the current user, rather than by the person who
|
|
* did the mount, since the current user needs to be
|
|
* able to write the file (that's why it is being
|
|
* copied in the first place).
|
|
*/
|
|
cn.cn_namelen = strlen(un->un_path);
|
|
if ((cn.cn_namelen + 1) > MAXPATHLEN)
|
|
return (ENAMETOOLONG);
|
|
cn.cn_pnbuf = PNBUF_GET();
|
|
memcpy(cn.cn_pnbuf, un->un_path, cn.cn_namelen+1);
|
|
cn.cn_nameiop = CREATE;
|
|
cn.cn_flags = (LOCKPARENT|HASBUF|SAVENAME|SAVESTART|ISLASTCN);
|
|
cn.cn_proc = p;
|
|
cn.cn_cred = p->p_ucred;
|
|
cn.cn_nameptr = cn.cn_pnbuf;
|
|
cn.cn_hash = un->un_hash;
|
|
cn.cn_consume = 0;
|
|
|
|
VREF(un->un_dirvp);
|
|
if ((error = relookup(un->un_dirvp, &vp, &cn)) != 0)
|
|
return (error);
|
|
vrele(un->un_dirvp);
|
|
|
|
if (vp) {
|
|
VOP_ABORTOP(un->un_dirvp, &cn);
|
|
if (un->un_dirvp == vp)
|
|
vrele(un->un_dirvp);
|
|
else
|
|
vput(un->un_dirvp);
|
|
vrele(vp);
|
|
return (EEXIST);
|
|
}
|
|
|
|
/*
|
|
* Good - there was no race to create the file
|
|
* so go ahead and create it. The permissions
|
|
* on the file will be 0666 modified by the
|
|
* current user's umask. Access to the file, while
|
|
* it is unioned, will require access to the top *and*
|
|
* bottom files. Access when not unioned will simply
|
|
* require access to the top-level file.
|
|
* TODO: confirm choice of access permissions.
|
|
*/
|
|
VATTR_NULL(vap);
|
|
vap->va_type = VREG;
|
|
vap->va_mode = cmode;
|
|
VOP_LEASE(un->un_dirvp, p, cred, LEASE_WRITE);
|
|
if ((error = VOP_CREATE(un->un_dirvp, &vp, &cn, vap)) != 0)
|
|
return (error);
|
|
|
|
if ((error = VOP_OPEN(vp, fmode, cred, p)) != 0) {
|
|
vput(vp);
|
|
return (error);
|
|
}
|
|
|
|
vp->v_writecount++;
|
|
*vpp = vp;
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
union_vn_close(vp, fmode, cred, p)
|
|
struct vnode *vp;
|
|
int fmode;
|
|
struct ucred *cred;
|
|
struct proc *p;
|
|
{
|
|
|
|
if (fmode & FWRITE)
|
|
--vp->v_writecount;
|
|
return (VOP_CLOSE(vp, fmode, cred, p));
|
|
}
|
|
|
|
void
|
|
union_removed_upper(un)
|
|
struct union_node *un;
|
|
{
|
|
#if 1
|
|
/*
|
|
* We do not set the uppervp to NULLVP here, because lowervp
|
|
* may also be NULLVP, so this routine would end up creating
|
|
* a bogus union node with no upper or lower VP (that causes
|
|
* pain in many places that assume at least one VP exists).
|
|
* Since we've removed this node from the cache hash chains,
|
|
* it won't be found again. When all current holders
|
|
* release it, union_inactive() will vgone() it.
|
|
*/
|
|
union_diruncache(un);
|
|
#else
|
|
union_newupper(un, NULLVP);
|
|
#endif
|
|
|
|
if (un->un_flags & UN_CACHED) {
|
|
un->un_flags &= ~UN_CACHED;
|
|
LIST_REMOVE(un, un_cache);
|
|
}
|
|
|
|
if (un->un_flags & UN_ULOCK) {
|
|
un->un_flags &= ~UN_ULOCK;
|
|
VOP_UNLOCK(un->un_uppervp, 0);
|
|
}
|
|
}
|
|
|
|
#if 0
|
|
struct vnode *
|
|
union_lowervp(vp)
|
|
struct vnode *vp;
|
|
{
|
|
struct union_node *un = VTOUNION(vp);
|
|
|
|
if ((un->un_lowervp != NULLVP) &&
|
|
(vp->v_type == un->un_lowervp->v_type)) {
|
|
if (vget(un->un_lowervp, 0) == 0)
|
|
return (un->un_lowervp);
|
|
}
|
|
|
|
return (NULLVP);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* determine whether a whiteout is needed
|
|
* during a remove/rmdir operation.
|
|
*/
|
|
int
|
|
union_dowhiteout(un, cred, p)
|
|
struct union_node *un;
|
|
struct ucred *cred;
|
|
struct proc *p;
|
|
{
|
|
struct vattr va;
|
|
|
|
if (un->un_lowervp != NULLVP)
|
|
return (1);
|
|
|
|
if (VOP_GETATTR(un->un_uppervp, &va, cred, p) == 0 &&
|
|
(va.va_flags & OPAQUE))
|
|
return (1);
|
|
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
union_dircache_r(vp, vppp, cntp)
|
|
struct vnode *vp;
|
|
struct vnode ***vppp;
|
|
int *cntp;
|
|
{
|
|
struct union_node *un;
|
|
|
|
if (vp->v_op != union_vnodeop_p) {
|
|
if (vppp) {
|
|
VREF(vp);
|
|
*(*vppp)++ = vp;
|
|
if (--(*cntp) == 0)
|
|
panic("union: dircache table too small");
|
|
} else {
|
|
(*cntp)++;
|
|
}
|
|
|
|
return;
|
|
}
|
|
|
|
un = VTOUNION(vp);
|
|
if (un->un_uppervp != NULLVP)
|
|
union_dircache_r(un->un_uppervp, vppp, cntp);
|
|
if (un->un_lowervp != NULLVP)
|
|
union_dircache_r(un->un_lowervp, vppp, cntp);
|
|
}
|
|
|
|
struct vnode *
|
|
union_dircache(vp, p)
|
|
struct vnode *vp;
|
|
struct proc *p;
|
|
{
|
|
int cnt;
|
|
struct vnode *nvp = NULLVP;
|
|
struct vnode **vpp;
|
|
struct vnode **dircache;
|
|
int error;
|
|
|
|
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
|
|
dircache = VTOUNION(vp)->un_dircache;
|
|
|
|
nvp = NULLVP;
|
|
|
|
if (dircache == 0) {
|
|
cnt = 0;
|
|
union_dircache_r(vp, 0, &cnt);
|
|
cnt++;
|
|
dircache = (struct vnode **)
|
|
malloc(cnt * sizeof(struct vnode *),
|
|
M_TEMP, M_WAITOK);
|
|
vpp = dircache;
|
|
union_dircache_r(vp, &vpp, &cnt);
|
|
VTOUNION(vp)->un_dircache = dircache;
|
|
*vpp = NULLVP;
|
|
vpp = dircache + 1;
|
|
} else {
|
|
vpp = dircache;
|
|
do {
|
|
if (*vpp++ == VTOUNION(vp)->un_uppervp)
|
|
break;
|
|
} while (*vpp != NULLVP);
|
|
}
|
|
|
|
if (*vpp == NULLVP)
|
|
goto out;
|
|
|
|
vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY);
|
|
VREF(*vpp);
|
|
error = union_allocvp(&nvp, vp->v_mount, NULLVP, NULLVP, 0, *vpp, NULLVP, 0);
|
|
if (!error) {
|
|
VTOUNION(vp)->un_dircache = 0;
|
|
VTOUNION(nvp)->un_dircache = dircache;
|
|
}
|
|
|
|
out:
|
|
VOP_UNLOCK(vp, 0);
|
|
return (nvp);
|
|
}
|
|
|
|
void
|
|
union_diruncache(un)
|
|
struct union_node *un;
|
|
{
|
|
struct vnode **vpp;
|
|
|
|
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;
|
|
}
|
|
}
|