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freebsd-dev/sys/fs/unionfs/union_subr.c
Warner Losh 2ff63af9b8 sys: Remove $FreeBSD$: one-line .h pattern 
Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/
2023-08-16 11:54:18 -06:00

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1994 Jan-Simon Pendry
* Copyright (c) 1994
* The Regents of the University of California. All rights reserved.
* Copyright (c) 2005, 2006, 2012 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc.
* Copyright (c) 2006, 2012 Daichi Goto <daichi@freebsd.org>
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)union_subr.c 8.20 (Berkeley) 5/20/95
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/dirent.h>
#include <sys/fcntl.h>
#include <sys/filedesc.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/taskqueue.h>
#include <sys/resourcevar.h>
#include <machine/atomic.h>
#include <security/mac/mac_framework.h>
#include <vm/uma.h>
#include <fs/unionfs/union.h>
#define NUNIONFSNODECACHE 16
#define UNIONFSHASHMASK (NUNIONFSNODECACHE - 1)
static MALLOC_DEFINE(M_UNIONFSHASH, "UNIONFS hash", "UNIONFS hash table");
MALLOC_DEFINE(M_UNIONFSNODE, "UNIONFS node", "UNIONFS vnode private part");
MALLOC_DEFINE(M_UNIONFSPATH, "UNIONFS path", "UNIONFS path private part");
static struct task unionfs_deferred_rele_task;
static struct mtx unionfs_deferred_rele_lock;
static STAILQ_HEAD(, unionfs_node) unionfs_deferred_rele_list =
STAILQ_HEAD_INITIALIZER(unionfs_deferred_rele_list);
static TASKQUEUE_DEFINE_THREAD(unionfs_rele);
unsigned int unionfs_ndeferred = 0;
SYSCTL_UINT(_vfs, OID_AUTO, unionfs_ndeferred, CTLFLAG_RD,
&unionfs_ndeferred, 0, "unionfs deferred vnode release");
static void unionfs_deferred_rele(void *, int);
/*
* Initialize
*/
int
unionfs_init(struct vfsconf *vfsp)
{
UNIONFSDEBUG("unionfs_init\n"); /* printed during system boot */
TASK_INIT(&unionfs_deferred_rele_task, 0, unionfs_deferred_rele, NULL);
mtx_init(&unionfs_deferred_rele_lock, "uniondefr", NULL, MTX_DEF);
return (0);
}
/*
* Uninitialize
*/
int
unionfs_uninit(struct vfsconf *vfsp)
{
taskqueue_quiesce(taskqueue_unionfs_rele);
taskqueue_free(taskqueue_unionfs_rele);
mtx_destroy(&unionfs_deferred_rele_lock);
return (0);
}
static void
unionfs_deferred_rele(void *arg __unused, int pending __unused)
{
STAILQ_HEAD(, unionfs_node) local_rele_list;
struct unionfs_node *unp, *tunp;
unsigned int ndeferred;
ndeferred = 0;
STAILQ_INIT(&local_rele_list);
mtx_lock(&unionfs_deferred_rele_lock);
STAILQ_CONCAT(&local_rele_list, &unionfs_deferred_rele_list);
mtx_unlock(&unionfs_deferred_rele_lock);
STAILQ_FOREACH_SAFE(unp, &local_rele_list, un_rele, tunp) {
++ndeferred;
MPASS(unp->un_dvp != NULL);
vrele(unp->un_dvp);
free(unp, M_UNIONFSNODE);
}
/* We expect this function to be single-threaded, thus no atomic */
unionfs_ndeferred += ndeferred;
}
static struct unionfs_node_hashhead *
unionfs_get_hashhead(struct vnode *dvp, struct vnode *lookup)
{
struct unionfs_node *unp;
unp = VTOUNIONFS(dvp);
return (&(unp->un_hashtbl[vfs_hash_index(lookup) & UNIONFSHASHMASK]));
}
/*
* Attempt to lookup a cached unionfs vnode by upper/lower vp
* from dvp, with dvp's interlock held.
*/
static struct vnode *
unionfs_get_cached_vnode_locked(struct vnode *lookup, struct vnode *dvp)
{
struct unionfs_node *unp;
struct unionfs_node_hashhead *hd;
struct vnode *vp;
hd = unionfs_get_hashhead(dvp, lookup);
LIST_FOREACH(unp, hd, un_hash) {
if (unp->un_uppervp == lookup ||
unp->un_lowervp == lookup) {
vp = UNIONFSTOV(unp);
VI_LOCK_FLAGS(vp, MTX_DUPOK);
vp->v_iflag &= ~VI_OWEINACT;
if (VN_IS_DOOMED(vp) ||
((vp->v_iflag & VI_DOINGINACT) != 0)) {
VI_UNLOCK(vp);
vp = NULLVP;
} else {
vrefl(vp);
VI_UNLOCK(vp);
}
return (vp);
}
}
return (NULLVP);
}
/*
* Get the cached vnode.
*/
static struct vnode *
unionfs_get_cached_vnode(struct vnode *uvp, struct vnode *lvp,
struct vnode *dvp)
{
struct vnode *vp;
vp = NULLVP;
VI_LOCK(dvp);
if (uvp != NULLVP)
vp = unionfs_get_cached_vnode_locked(uvp, dvp);
else if (lvp != NULLVP)
vp = unionfs_get_cached_vnode_locked(lvp, dvp);
VI_UNLOCK(dvp);
return (vp);
}
/*
* Add the new vnode into cache.
*/
static struct vnode *
unionfs_ins_cached_vnode(struct unionfs_node *uncp,
struct vnode *dvp)
{
struct unionfs_node_hashhead *hd;
struct vnode *vp;
ASSERT_VOP_ELOCKED(uncp->un_uppervp, __func__);
ASSERT_VOP_ELOCKED(uncp->un_lowervp, __func__);
KASSERT(uncp->un_uppervp == NULLVP || uncp->un_uppervp->v_type == VDIR,
("%s: v_type != VDIR", __func__));
KASSERT(uncp->un_lowervp == NULLVP || uncp->un_lowervp->v_type == VDIR,
("%s: v_type != VDIR", __func__));
vp = NULLVP;
VI_LOCK(dvp);
if (uncp->un_uppervp != NULL)
vp = unionfs_get_cached_vnode_locked(uncp->un_uppervp, dvp);
else if (uncp->un_lowervp != NULL)
vp = unionfs_get_cached_vnode_locked(uncp->un_lowervp, dvp);
if (vp == NULLVP) {
hd = unionfs_get_hashhead(dvp, (uncp->un_uppervp != NULLVP ?
uncp->un_uppervp : uncp->un_lowervp));
LIST_INSERT_HEAD(hd, uncp, un_hash);
}
VI_UNLOCK(dvp);
return (vp);
}
/*
* Remove the vnode.
*/
static void
unionfs_rem_cached_vnode(struct unionfs_node *unp, struct vnode *dvp)
{
KASSERT(unp != NULL, ("%s: null node", __func__));
KASSERT(dvp != NULLVP,
("%s: null parent vnode", __func__));
VI_LOCK(dvp);
if (unp->un_hash.le_prev != NULL) {
LIST_REMOVE(unp, un_hash);
unp->un_hash.le_next = NULL;
unp->un_hash.le_prev = NULL;
}
VI_UNLOCK(dvp);
}
/*
* Common cleanup handling for unionfs_nodeget
* Upper, lower, and parent directory vnodes are expected to be referenced by
* the caller. Upper and lower vnodes, if non-NULL, are also expected to be
* exclusively locked by the caller.
* This function will return with the caller's locks and references undone.
*/
static void
unionfs_nodeget_cleanup(struct vnode *vp, struct unionfs_node *unp)
{
/*
* Lock and reset the default vnode lock; vgone() expects a locked
* vnode, and we're going to reset the vnode ops.
*/
lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL);
/*
* Clear out private data and reset the vnode ops to avoid use of
* unionfs vnode ops on a partially constructed vnode.
*/
VI_LOCK(vp);
vp->v_data = NULL;
vp->v_vnlock = &vp->v_lock;
vp->v_op = &dead_vnodeops;
VI_UNLOCK(vp);
vgone(vp);
vput(vp);
if (unp->un_dvp != NULLVP)
vrele(unp->un_dvp);
if (unp->un_uppervp != NULLVP)
vput(unp->un_uppervp);
if (unp->un_lowervp != NULLVP)
vput(unp->un_lowervp);
if (unp->un_hashtbl != NULL)
hashdestroy(unp->un_hashtbl, M_UNIONFSHASH, UNIONFSHASHMASK);
free(unp->un_path, M_UNIONFSPATH);
free(unp, M_UNIONFSNODE);
}
/*
* Make a new or get existing unionfs node.
*
* uppervp and lowervp should be unlocked. Because if new unionfs vnode is
* locked, uppervp or lowervp is locked too. In order to prevent dead lock,
* you should not lock plurality simultaneously.
*/
int
unionfs_nodeget(struct mount *mp, struct vnode *uppervp,
struct vnode *lowervp, struct vnode *dvp, struct vnode **vpp,
struct componentname *cnp)
{
char *path;
struct unionfs_mount *ump;
struct unionfs_node *unp;
struct vnode *vp;
u_long hashmask;
int error;
int lkflags;
__enum_uint8(vtype) vt;
error = 0;
ump = MOUNTTOUNIONFSMOUNT(mp);
lkflags = (cnp ? cnp->cn_lkflags : 0);
path = (cnp ? cnp->cn_nameptr : NULL);
*vpp = NULLVP;
if (uppervp == NULLVP && lowervp == NULLVP)
panic("%s: upper and lower is null", __func__);
vt = (uppervp != NULLVP ? uppervp->v_type : lowervp->v_type);
/* If it has no ISLASTCN flag, path check is skipped. */
if (cnp && !(cnp->cn_flags & ISLASTCN))
path = NULL;
/* check the cache */
if (dvp != NULLVP && vt == VDIR) {
vp = unionfs_get_cached_vnode(uppervp, lowervp, dvp);
if (vp != NULLVP) {
*vpp = vp;
goto unionfs_nodeget_out;
}
}
unp = malloc(sizeof(struct unionfs_node),
M_UNIONFSNODE, M_WAITOK | M_ZERO);
error = getnewvnode("unionfs", mp, &unionfs_vnodeops, &vp);
if (error != 0) {
free(unp, M_UNIONFSNODE);
return (error);
}
if (dvp != NULLVP)
vref(dvp);
if (uppervp != NULLVP)
vref(uppervp);
if (lowervp != NULLVP)
vref(lowervp);
if (vt == VDIR) {
unp->un_hashtbl = hashinit(NUNIONFSNODECACHE, M_UNIONFSHASH,
&hashmask);
KASSERT(hashmask == UNIONFSHASHMASK,
("unexpected unionfs hash mask 0x%lx", hashmask));
}
unp->un_vnode = vp;
unp->un_uppervp = uppervp;
unp->un_lowervp = lowervp;
unp->un_dvp = dvp;
if (uppervp != NULLVP)
vp->v_vnlock = uppervp->v_vnlock;
else
vp->v_vnlock = lowervp->v_vnlock;
if (path != NULL) {
unp->un_path = malloc(cnp->cn_namelen + 1,
M_UNIONFSPATH, M_WAITOK | M_ZERO);
bcopy(cnp->cn_nameptr, unp->un_path, cnp->cn_namelen);
unp->un_path[cnp->cn_namelen] = '\0';
unp->un_pathlen = cnp->cn_namelen;
}
vp->v_type = vt;
vp->v_data = unp;
/*
* TODO: This is an imperfect check, as there's no guarantee that
* the underlying filesystems will always return vnode pointers
* for the root inodes that match our cached values. To reduce
* the likelihood of failure, for example in the case where either
* vnode has been forcibly doomed, we check both pointers and set
* VV_ROOT if either matches.
*/
if (ump->um_uppervp == uppervp || ump->um_lowervp == lowervp)
vp->v_vflag |= VV_ROOT;
KASSERT(dvp != NULL || (vp->v_vflag & VV_ROOT) != 0,
("%s: NULL dvp for non-root vp %p", __func__, vp));
vn_lock_pair(lowervp, false, LK_EXCLUSIVE, uppervp, false,
LK_EXCLUSIVE);
error = insmntque1(vp, mp);
if (error != 0) {
unionfs_nodeget_cleanup(vp, unp);
return (error);
}
if (lowervp != NULL && VN_IS_DOOMED(lowervp)) {
vput(lowervp);
unp->un_lowervp = lowervp = NULL;
}
if (uppervp != NULL && VN_IS_DOOMED(uppervp)) {
vput(uppervp);
unp->un_uppervp = uppervp = NULL;
if (lowervp != NULLVP)
vp->v_vnlock = lowervp->v_vnlock;
}
if (lowervp == NULL && uppervp == NULL) {
unionfs_nodeget_cleanup(vp, unp);
return (ENOENT);
}
vn_set_state(vp, VSTATE_CONSTRUCTED);
if (dvp != NULLVP && vt == VDIR)
*vpp = unionfs_ins_cached_vnode(unp, dvp);
if (*vpp != NULLVP) {
unionfs_nodeget_cleanup(vp, unp);
vp = *vpp;
} else {
if (uppervp != NULL)
VOP_UNLOCK(uppervp);
if (lowervp != NULL)
VOP_UNLOCK(lowervp);
*vpp = vp;
}
unionfs_nodeget_out:
if (lkflags & LK_TYPE_MASK)
vn_lock(vp, lkflags | LK_RETRY);
return (0);
}
/*
* Clean up the unionfs node.
*/
void
unionfs_noderem(struct vnode *vp)
{
struct unionfs_node *unp, *unp_t1, *unp_t2;
struct unionfs_node_hashhead *hd;
struct unionfs_node_status *unsp, *unsp_tmp;
struct vnode *lvp;
struct vnode *uvp;
struct vnode *dvp;
int count;
int writerefs;
/*
* The root vnode lock may be recursed during unmount, because
* it may share the same lock as the unionfs mount's covered vnode,
* which is locked across VFS_UNMOUNT(). This lock will then be
* recursively taken during the vflush() issued by unionfs_unmount().
* But we still only need to lock the unionfs lock once, because only
* one of those lock operations was taken against a unionfs vnode and
* will be undone against a unionfs vnode.
*/
KASSERT(vp->v_vnlock->lk_recurse == 0 || (vp->v_vflag & VV_ROOT) != 0,
("%s: vnode %p locked recursively", __func__, vp));
if (lockmgr(&vp->v_lock, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0)
panic("%s: failed to acquire lock for vnode lock", __func__);
/*
* Use the interlock to protect the clearing of v_data to
* prevent faults in unionfs_lock().
*/
VI_LOCK(vp);
unp = VTOUNIONFS(vp);
lvp = unp->un_lowervp;
uvp = unp->un_uppervp;
dvp = unp->un_dvp;
unp->un_lowervp = unp->un_uppervp = NULLVP;
vp->v_vnlock = &(vp->v_lock);
vp->v_data = NULL;
vp->v_object = NULL;
if (unp->un_hashtbl != NULL) {
/*
* Clear out any cached child vnodes. This should only
* be necessary during forced unmount, when the vnode may
* be reclaimed with a non-zero use count. Otherwise the
* reference held by each child should prevent reclamation.
*/
for (count = 0; count <= UNIONFSHASHMASK; count++) {
hd = unp->un_hashtbl + count;
LIST_FOREACH_SAFE(unp_t1, hd, un_hash, unp_t2) {
LIST_REMOVE(unp_t1, un_hash);
unp_t1->un_hash.le_next = NULL;
unp_t1->un_hash.le_prev = NULL;
}
}
}
VI_UNLOCK(vp);
writerefs = atomic_load_int(&vp->v_writecount);
VNASSERT(writerefs >= 0, vp,
("%s: write count %d, unexpected text ref", __func__, writerefs));
/*
* If we were opened for write, we leased the write reference
* to the lower vnode. If this is a reclamation due to the
* forced unmount, undo the reference now.
*/
if (writerefs > 0) {
VNASSERT(uvp != NULL, vp,
("%s: write reference without upper vnode", __func__));
VOP_ADD_WRITECOUNT(uvp, -writerefs);
}
if (lvp != NULLVP)
VOP_UNLOCK(lvp);
if (uvp != NULLVP)
VOP_UNLOCK(uvp);
if (dvp != NULLVP)
unionfs_rem_cached_vnode(unp, dvp);
if (lvp != NULLVP)
vrele(lvp);
if (uvp != NULLVP)
vrele(uvp);
if (unp->un_path != NULL) {
free(unp->un_path, M_UNIONFSPATH);
unp->un_path = NULL;
unp->un_pathlen = 0;
}
if (unp->un_hashtbl != NULL) {
hashdestroy(unp->un_hashtbl, M_UNIONFSHASH, UNIONFSHASHMASK);
}
LIST_FOREACH_SAFE(unsp, &(unp->un_unshead), uns_list, unsp_tmp) {
LIST_REMOVE(unsp, uns_list);
free(unsp, M_TEMP);
}
if (dvp != NULLVP) {
mtx_lock(&unionfs_deferred_rele_lock);
STAILQ_INSERT_TAIL(&unionfs_deferred_rele_list, unp, un_rele);
mtx_unlock(&unionfs_deferred_rele_lock);
taskqueue_enqueue(taskqueue_unionfs_rele,
&unionfs_deferred_rele_task);
} else
free(unp, M_UNIONFSNODE);
}
/*
* Get the unionfs node status object for the vnode corresponding to unp,
* for the process that owns td. Allocate a new status object if one
* does not already exist.
*/
void
unionfs_get_node_status(struct unionfs_node *unp, struct thread *td,
struct unionfs_node_status **unspp)
{
struct unionfs_node_status *unsp;
pid_t pid;
pid = td->td_proc->p_pid;
KASSERT(NULL != unspp, ("%s: NULL status", __func__));
ASSERT_VOP_ELOCKED(UNIONFSTOV(unp), __func__);
LIST_FOREACH(unsp, &(unp->un_unshead), uns_list) {
if (unsp->uns_pid == pid) {
*unspp = unsp;
return;
}
}
/* create a new unionfs node status */
unsp = malloc(sizeof(struct unionfs_node_status),
M_TEMP, M_WAITOK | M_ZERO);
unsp->uns_pid = pid;
LIST_INSERT_HEAD(&(unp->un_unshead), unsp, uns_list);
*unspp = unsp;
}
/*
* Remove the unionfs node status, if you can.
* You need exclusive lock this vnode.
*/
void
unionfs_tryrem_node_status(struct unionfs_node *unp,
struct unionfs_node_status *unsp)
{
KASSERT(NULL != unsp, ("%s: NULL status", __func__));
ASSERT_VOP_ELOCKED(UNIONFSTOV(unp), __func__);
if (0 < unsp->uns_lower_opencnt || 0 < unsp->uns_upper_opencnt)
return;
LIST_REMOVE(unsp, uns_list);
free(unsp, M_TEMP);
}
/*
* Create upper node attr.
*/
void
unionfs_create_uppervattr_core(struct unionfs_mount *ump, struct vattr *lva,
struct vattr *uva, struct thread *td)
{
VATTR_NULL(uva);
uva->va_type = lva->va_type;
uva->va_atime = lva->va_atime;
uva->va_mtime = lva->va_mtime;
uva->va_ctime = lva->va_ctime;
switch (ump->um_copymode) {
case UNIONFS_TRANSPARENT:
uva->va_mode = lva->va_mode;
uva->va_uid = lva->va_uid;
uva->va_gid = lva->va_gid;
break;
case UNIONFS_MASQUERADE:
if (ump->um_uid == lva->va_uid) {
uva->va_mode = lva->va_mode & 077077;
uva->va_mode |= (lva->va_type == VDIR ?
ump->um_udir : ump->um_ufile) & 0700;
uva->va_uid = lva->va_uid;
uva->va_gid = lva->va_gid;
} else {
uva->va_mode = (lva->va_type == VDIR ?
ump->um_udir : ump->um_ufile);
uva->va_uid = ump->um_uid;
uva->va_gid = ump->um_gid;
}
break;
default: /* UNIONFS_TRADITIONAL */
uva->va_mode = 0777 & ~td->td_proc->p_pd->pd_cmask;
uva->va_uid = ump->um_uid;
uva->va_gid = ump->um_gid;
break;
}
}
/*
* Create upper node attr.
*/
int
unionfs_create_uppervattr(struct unionfs_mount *ump, struct vnode *lvp,
struct vattr *uva, struct ucred *cred, struct thread *td)
{
struct vattr lva;
int error;
if ((error = VOP_GETATTR(lvp, &lva, cred)))
return (error);
unionfs_create_uppervattr_core(ump, &lva, uva, td);
return (error);
}
/*
* relookup
*
* dvp should be locked on entry and will be locked on return.
*
* If an error is returned, *vpp will be invalid, otherwise it will hold a
* locked, referenced vnode. If *vpp == dvp then remember that only one
* LK_EXCLUSIVE lock is held.
*/
int
unionfs_relookup(struct vnode *dvp, struct vnode **vpp,
struct componentname *cnp, struct componentname *cn, struct thread *td,
char *path, int pathlen, u_long nameiop)
{
int error;
bool refstart;
cn->cn_namelen = pathlen;
cn->cn_pnbuf = path;
cn->cn_nameiop = nameiop;
cn->cn_flags = (LOCKPARENT | LOCKLEAF | ISLASTCN);
cn->cn_lkflags = LK_EXCLUSIVE;
cn->cn_cred = cnp->cn_cred;
cn->cn_nameptr = cn->cn_pnbuf;
refstart = false;
if (nameiop == DELETE) {
cn->cn_flags |= (cnp->cn_flags & DOWHITEOUT);
} else if (nameiop == RENAME) {
refstart = true;
} else if (nameiop == CREATE) {
cn->cn_flags |= NOCACHE;
}
vref(dvp);
VOP_UNLOCK(dvp);
if ((error = vfs_relookup(dvp, vpp, cn, refstart))) {
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
} else
vrele(dvp);
KASSERT(cn->cn_pnbuf == path, ("%s: cn_pnbuf changed", __func__));
return (error);
}
/*
* relookup for CREATE namei operation.
*
* dvp is unionfs vnode. dvp should be locked.
*
* If it called 'unionfs_copyfile' function by unionfs_link etc,
* VOP_LOOKUP information is broken.
* So it need relookup in order to create link etc.
*/
int
unionfs_relookup_for_create(struct vnode *dvp, struct componentname *cnp,
struct thread *td)
{
struct vnode *udvp;
struct vnode *vp;
struct componentname cn;
int error;
udvp = UNIONFSVPTOUPPERVP(dvp);
vp = NULLVP;
error = unionfs_relookup(udvp, &vp, cnp, &cn, td, cnp->cn_nameptr,
cnp->cn_namelen, CREATE);
if (error)
return (error);
if (vp != NULLVP) {
if (udvp == vp)
vrele(vp);
else
vput(vp);
error = EEXIST;
}
return (error);
}
/*
* relookup for DELETE namei operation.
*
* dvp is unionfs vnode. dvp should be locked.
*/
int
unionfs_relookup_for_delete(struct vnode *dvp, struct componentname *cnp,
struct thread *td)
{
struct vnode *udvp;
struct vnode *vp;
struct componentname cn;
int error;
udvp = UNIONFSVPTOUPPERVP(dvp);
vp = NULLVP;
error = unionfs_relookup(udvp, &vp, cnp, &cn, td, cnp->cn_nameptr,
cnp->cn_namelen, DELETE);
if (error)
return (error);
if (vp == NULLVP)
error = ENOENT;
else {
if (udvp == vp)
vrele(vp);
else
vput(vp);
}
return (error);
}
/*
* relookup for RENAME namei operation.
*
* dvp is unionfs vnode. dvp should be locked.
*/
int
unionfs_relookup_for_rename(struct vnode *dvp, struct componentname *cnp,
struct thread *td)
{
struct vnode *udvp;
struct vnode *vp;
struct componentname cn;
int error;
udvp = UNIONFSVPTOUPPERVP(dvp);
vp = NULLVP;
error = unionfs_relookup(udvp, &vp, cnp, &cn, td, cnp->cn_nameptr,
cnp->cn_namelen, RENAME);
if (error)
return (error);
if (vp != NULLVP) {
if (udvp == vp)
vrele(vp);
else
vput(vp);
}
return (error);
}
/*
* Update the unionfs_node.
*
* uvp is new locked upper vnode. unionfs vnode's lock will be exchanged to the
* uvp's lock and lower's lock will be unlocked.
*/
static void
unionfs_node_update(struct unionfs_node *unp, struct vnode *uvp,
struct thread *td)
{
struct unionfs_node_hashhead *hd;
struct vnode *vp;
struct vnode *lvp;
struct vnode *dvp;
unsigned count, lockrec;
vp = UNIONFSTOV(unp);
lvp = unp->un_lowervp;
ASSERT_VOP_ELOCKED(lvp, __func__);
ASSERT_VOP_ELOCKED(uvp, __func__);
dvp = unp->un_dvp;
VNASSERT(vp->v_writecount == 0, vp,
("%s: non-zero writecount", __func__));
/*
* Update the upper vnode's lock state to match the lower vnode,
* and then switch the unionfs vnode's lock to the upper vnode.
*/
lockrec = lvp->v_vnlock->lk_recurse;
for (count = 0; count < lockrec; count++)
vn_lock(uvp, LK_EXCLUSIVE | LK_CANRECURSE | LK_RETRY);
VI_LOCK(vp);
unp->un_uppervp = uvp;
vp->v_vnlock = uvp->v_vnlock;
VI_UNLOCK(vp);
/*
* Re-cache the unionfs vnode against the upper vnode
*/
if (dvp != NULLVP && vp->v_type == VDIR) {
VI_LOCK(dvp);
if (unp->un_hash.le_prev != NULL) {
LIST_REMOVE(unp, un_hash);
hd = unionfs_get_hashhead(dvp, uvp);
LIST_INSERT_HEAD(hd, unp, un_hash);
}
VI_UNLOCK(unp->un_dvp);
}
}
/*
* Create a new shadow dir.
*
* udvp should be locked on entry and will be locked on return.
*
* If no error returned, unp will be updated.
*/
int
unionfs_mkshadowdir(struct unionfs_mount *ump, struct vnode *udvp,
struct unionfs_node *unp, struct componentname *cnp, struct thread *td)
{
struct vnode *lvp;
struct vnode *uvp;
struct vattr va;
struct vattr lva;
struct nameidata nd;
struct mount *mp;
struct ucred *cred;
struct ucred *credbk;
struct uidinfo *rootinfo;
int error;
if (unp->un_uppervp != NULLVP)
return (EEXIST);
lvp = unp->un_lowervp;
uvp = NULLVP;
credbk = cnp->cn_cred;
/* Authority change to root */
rootinfo = uifind((uid_t)0);
cred = crdup(cnp->cn_cred);
/*
* The calls to chgproccnt() are needed to compensate for change_ruid()
* calling chgproccnt().
*/
chgproccnt(cred->cr_ruidinfo, 1, 0);
change_euid(cred, rootinfo);
change_ruid(cred, rootinfo);
change_svuid(cred, (uid_t)0);
uifree(rootinfo);
cnp->cn_cred = cred;
memset(&nd.ni_cnd, 0, sizeof(struct componentname));
NDPREINIT(&nd);
if ((error = VOP_GETATTR(lvp, &lva, cnp->cn_cred)))
goto unionfs_mkshadowdir_abort;
if ((error = unionfs_relookup(udvp, &uvp, cnp, &nd.ni_cnd, td,
cnp->cn_nameptr, cnp->cn_namelen, CREATE)))
goto unionfs_mkshadowdir_abort;
if (uvp != NULLVP) {
if (udvp == uvp)
vrele(uvp);
else
vput(uvp);
error = EEXIST;
goto unionfs_mkshadowdir_abort;
}
if ((error = vn_start_write(udvp, &mp, V_WAIT | V_PCATCH)))
goto unionfs_mkshadowdir_abort;
unionfs_create_uppervattr_core(ump, &lva, &va, td);
error = VOP_MKDIR(udvp, &uvp, &nd.ni_cnd, &va);
if (!error) {
unionfs_node_update(unp, uvp, td);
/*
* XXX The bug which cannot set uid/gid was corrected.
* Ignore errors.
*/
va.va_type = VNON;
VOP_SETATTR(uvp, &va, nd.ni_cnd.cn_cred);
}
vn_finished_write(mp);
unionfs_mkshadowdir_abort:
cnp->cn_cred = credbk;
chgproccnt(cred->cr_ruidinfo, -1, 0);
crfree(cred);
return (error);
}
/*
* Create a new whiteout.
*
* dvp should be locked on entry and will be locked on return.
*/
int
unionfs_mkwhiteout(struct vnode *dvp, struct componentname *cnp,
struct thread *td, char *path, int pathlen)
{
struct vnode *wvp;
struct nameidata nd;
struct mount *mp;
int error;
wvp = NULLVP;
NDPREINIT(&nd);
if ((error = unionfs_relookup(dvp, &wvp, cnp, &nd.ni_cnd, td, path,
pathlen, CREATE))) {
return (error);
}
if (wvp != NULLVP) {
if (dvp == wvp)
vrele(wvp);
else
vput(wvp);
return (EEXIST);
}
if ((error = vn_start_write(dvp, &mp, V_WAIT | V_PCATCH)))
goto unionfs_mkwhiteout_free_out;
error = VOP_WHITEOUT(dvp, &nd.ni_cnd, CREATE);
vn_finished_write(mp);
unionfs_mkwhiteout_free_out:
return (error);
}
/*
* Create a new vnode for create a new shadow file.
*
* If an error is returned, *vpp will be invalid, otherwise it will hold a
* locked, referenced and opened vnode.
*
* unp is never updated.
*/
static int
unionfs_vn_create_on_upper(struct vnode **vpp, struct vnode *udvp,
struct unionfs_node *unp, struct vattr *uvap, struct thread *td)
{
struct unionfs_mount *ump;
struct vnode *vp;
struct vnode *lvp;
struct ucred *cred;
struct vattr lva;
struct nameidata nd;
int fmode;
int error;
ump = MOUNTTOUNIONFSMOUNT(UNIONFSTOV(unp)->v_mount);
vp = NULLVP;
lvp = unp->un_lowervp;
cred = td->td_ucred;
fmode = FFLAGS(O_WRONLY | O_CREAT | O_TRUNC | O_EXCL);
error = 0;
if ((error = VOP_GETATTR(lvp, &lva, cred)) != 0)
return (error);
unionfs_create_uppervattr_core(ump, &lva, uvap, td);
if (unp->un_path == NULL)
panic("%s: NULL un_path", __func__);
nd.ni_cnd.cn_namelen = unp->un_pathlen;
nd.ni_cnd.cn_pnbuf = unp->un_path;
nd.ni_cnd.cn_nameiop = CREATE;
nd.ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF | ISLASTCN;
nd.ni_cnd.cn_lkflags = LK_EXCLUSIVE;
nd.ni_cnd.cn_cred = cred;
nd.ni_cnd.cn_nameptr = nd.ni_cnd.cn_pnbuf;
NDPREINIT(&nd);
vref(udvp);
if ((error = vfs_relookup(udvp, &vp, &nd.ni_cnd, false)) != 0)
goto unionfs_vn_create_on_upper_free_out2;
vrele(udvp);
if (vp != NULLVP) {
if (vp == udvp)
vrele(vp);
else
vput(vp);
error = EEXIST;
goto unionfs_vn_create_on_upper_free_out1;
}
if ((error = VOP_CREATE(udvp, &vp, &nd.ni_cnd, uvap)) != 0)
goto unionfs_vn_create_on_upper_free_out1;
if ((error = VOP_OPEN(vp, fmode, cred, td, NULL)) != 0) {
vput(vp);
goto unionfs_vn_create_on_upper_free_out1;
}
error = VOP_ADD_WRITECOUNT(vp, 1);
CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
__func__, vp, vp->v_writecount);
if (error == 0) {
*vpp = vp;
} else {
VOP_CLOSE(vp, fmode, cred, td);
}
unionfs_vn_create_on_upper_free_out1:
VOP_UNLOCK(udvp);
unionfs_vn_create_on_upper_free_out2:
KASSERT(nd.ni_cnd.cn_pnbuf == unp->un_path,
("%s: cn_pnbuf changed", __func__));
return (error);
}
/*
* Copy from lvp to uvp.
*
* lvp and uvp should be locked and opened on entry and will be locked and
* opened on return.
*/
static int
unionfs_copyfile_core(struct vnode *lvp, struct vnode *uvp,
struct ucred *cred, struct thread *td)
{
char *buf;
struct uio uio;
struct iovec iov;
off_t offset;
int count;
int error;
int bufoffset;
error = 0;
memset(&uio, 0, sizeof(uio));
uio.uio_td = td;
uio.uio_segflg = UIO_SYSSPACE;
uio.uio_offset = 0;
buf = malloc(MAXBSIZE, M_TEMP, M_WAITOK);
while (error == 0) {
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;
if ((error = VOP_READ(lvp, &uio, 0, cred)) != 0)
break;
if ((count = MAXBSIZE - uio.uio_resid) == 0)
break;
bufoffset = 0;
while (bufoffset < count) {
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
iov.iov_base = buf + bufoffset;
iov.iov_len = count - bufoffset;
uio.uio_offset = offset + bufoffset;
uio.uio_resid = iov.iov_len;
uio.uio_rw = UIO_WRITE;
if ((error = VOP_WRITE(uvp, &uio, 0, cred)) != 0)
break;
bufoffset += (count - bufoffset) - uio.uio_resid;
}
uio.uio_offset = offset + bufoffset;
}
free(buf, M_TEMP);
return (error);
}
/*
* Copy file from lower to upper.
*
* If you need copy of the contents, set 1 to docopy. Otherwise, set 0 to
* docopy.
*
* If no error returned, unp will be updated.
*/
int
unionfs_copyfile(struct unionfs_node *unp, int docopy, struct ucred *cred,
struct thread *td)
{
struct mount *mp;
struct vnode *udvp;
struct vnode *lvp;
struct vnode *uvp;
struct vattr uva;
int error;
lvp = unp->un_lowervp;
uvp = NULLVP;
if ((UNIONFSTOV(unp)->v_mount->mnt_flag & MNT_RDONLY))
return (EROFS);
if (unp->un_dvp == NULLVP)
return (EINVAL);
if (unp->un_uppervp != NULLVP)
return (EEXIST);
udvp = VTOUNIONFS(unp->un_dvp)->un_uppervp;
if (udvp == NULLVP)
return (EROFS);
if ((udvp->v_mount->mnt_flag & MNT_RDONLY))
return (EROFS);
error = VOP_ACCESS(lvp, VREAD, cred, td);
if (error != 0)
return (error);
if ((error = vn_start_write(udvp, &mp, V_WAIT | V_PCATCH)) != 0)
return (error);
error = unionfs_vn_create_on_upper(&uvp, udvp, unp, &uva, td);
if (error != 0) {
vn_finished_write(mp);
return (error);
}
if (docopy != 0) {
error = VOP_OPEN(lvp, FREAD, cred, td, NULL);
if (error == 0) {
error = unionfs_copyfile_core(lvp, uvp, cred, td);
VOP_CLOSE(lvp, FREAD, cred, td);
}
}
VOP_CLOSE(uvp, FWRITE, cred, td);
VOP_ADD_WRITECOUNT_CHECKED(uvp, -1);
CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
__func__, uvp, uvp->v_writecount);
vn_finished_write(mp);
if (error == 0) {
/* Reset the attributes. Ignore errors. */
uva.va_type = VNON;
VOP_SETATTR(uvp, &uva, cred);
}
unionfs_node_update(unp, uvp, td);
return (error);
}
/*
* It checks whether vp can rmdir. (check empty)
*
* vp is unionfs vnode.
* vp should be locked.
*/
int
unionfs_check_rmdir(struct vnode *vp, struct ucred *cred, struct thread *td)
{
struct vnode *uvp;
struct vnode *lvp;
struct vnode *tvp;
struct dirent *dp;
struct dirent *edp;
struct componentname cn;
struct iovec iov;
struct uio uio;
struct vattr va;
int error;
int eofflag;
int lookuperr;
/*
* The size of buf needs to be larger than DIRBLKSIZ.
*/
char buf[256 * 6];
ASSERT_VOP_ELOCKED(vp, __func__);
eofflag = 0;
uvp = UNIONFSVPTOUPPERVP(vp);
lvp = UNIONFSVPTOLOWERVP(vp);
/* check opaque */
if ((error = VOP_GETATTR(uvp, &va, cred)) != 0)
return (error);
if (va.va_flags & OPAQUE)
return (0);
/* open vnode */
#ifdef MAC
if ((error = mac_vnode_check_open(cred, vp, VEXEC|VREAD)) != 0)
return (error);
#endif
if ((error = VOP_ACCESS(vp, VEXEC|VREAD, cred, td)) != 0)
return (error);
if ((error = VOP_OPEN(vp, FREAD, cred, td, NULL)) != 0)
return (error);
uio.uio_rw = UIO_READ;
uio.uio_segflg = UIO_SYSSPACE;
uio.uio_td = td;
uio.uio_offset = 0;
#ifdef MAC
error = mac_vnode_check_readdir(td->td_ucred, lvp);
#endif
while (!error && !eofflag) {
iov.iov_base = buf;
iov.iov_len = sizeof(buf);
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_resid = iov.iov_len;
error = VOP_READDIR(lvp, &uio, cred, &eofflag, NULL, NULL);
if (error != 0)
break;
KASSERT(eofflag != 0 || uio.uio_resid < sizeof(buf),
("%s: empty read from lower FS", __func__));
edp = (struct dirent*)&buf[sizeof(buf) - uio.uio_resid];
for (dp = (struct dirent*)buf; !error && dp < edp;
dp = (struct dirent*)((caddr_t)dp + dp->d_reclen)) {
if (dp->d_type == DT_WHT || dp->d_fileno == 0 ||
(dp->d_namlen == 1 && dp->d_name[0] == '.') ||
(dp->d_namlen == 2 && !bcmp(dp->d_name, "..", 2)))
continue;
cn.cn_namelen = dp->d_namlen;
cn.cn_pnbuf = NULL;
cn.cn_nameptr = dp->d_name;
cn.cn_nameiop = LOOKUP;
cn.cn_flags = LOCKPARENT | LOCKLEAF | RDONLY | ISLASTCN;
cn.cn_lkflags = LK_EXCLUSIVE;
cn.cn_cred = cred;
/*
* check entry in lower.
* Sometimes, readdir function returns
* wrong entry.
*/
lookuperr = VOP_LOOKUP(lvp, &tvp, &cn);
if (!lookuperr)
vput(tvp);
else
continue; /* skip entry */
/*
* check entry
* If it has no exist/whiteout entry in upper,
* directory is not empty.
*/
cn.cn_flags = LOCKPARENT | LOCKLEAF | RDONLY | ISLASTCN;
lookuperr = VOP_LOOKUP(uvp, &tvp, &cn);
if (!lookuperr)
vput(tvp);
/* ignore exist or whiteout entry */
if (!lookuperr ||
(lookuperr == ENOENT && (cn.cn_flags & ISWHITEOUT)))
continue;
error = ENOTEMPTY;
}
}
/* close vnode */
VOP_CLOSE(vp, FREAD, cred, td);
return (error);
}
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