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NetBSD/sys/kern/vfs_subr.c

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/* $NetBSD: vfs_subr.c,v 1.336 2008/04/04 20:13:18 cegger Exp $ */
/*-
* Copyright (c) 1997, 1998, 2004, 2005, 2007, 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center, by Charles M. Hannum, and by Andrew Doran.
*
* 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 NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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.
*
* @(#)vfs_subr.c 8.13 (Berkeley) 4/18/94
*/
/*
* External virtual filesystem routines.
*
* This file contains vfs subroutines which are heavily dependant on
* the kernel and are not suitable for standalone use. Examples include
* routines involved vnode and mountpoint management.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_subr.c,v 1.336 2008/04/04 20:13:18 cegger Exp $");
#include "opt_ddb.h"
#include "opt_compat_netbsd.h"
#include "opt_compat_43.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <sys/mount.h>
#include <sys/fcntl.h>
#include <sys/vnode.h>
#include <sys/stat.h>
#include <sys/namei.h>
#include <sys/ucred.h>
#include <sys/buf.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/syscallargs.h>
#include <sys/device.h>
#include <sys/filedesc.h>
#include <sys/kauth.h>
#include <sys/atomic.h>
#include <sys/kthread.h>
#include <miscfs/specfs/specdev.h>
#include <miscfs/syncfs/syncfs.h>
#include <uvm/uvm.h>
#include <uvm/uvm_readahead.h>
#include <uvm/uvm_ddb.h>
#include <sys/sysctl.h>
extern int dovfsusermount; /* 1 => permit any user to mount filesystems */
extern int vfs_magiclinks; /* 1 => expand "magic" symlinks */
static vnodelst_t vnode_free_list = TAILQ_HEAD_INITIALIZER(vnode_free_list);
static vnodelst_t vnode_hold_list = TAILQ_HEAD_INITIALIZER(vnode_hold_list);
static vnodelst_t vrele_list = TAILQ_HEAD_INITIALIZER(vrele_list);
static int vrele_pending;
static kmutex_t vrele_lock;
static kcondvar_t vrele_cv;
static lwp_t *vrele_lwp;
static pool_cache_t vnode_cache;
MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes");
/*
* Local declarations.
*/
static void vrele_thread(void *);
static void insmntque(vnode_t *, struct mount *);
static int getdevvp(dev_t, vnode_t **, enum vtype);
static vnode_t *getcleanvnode(void);;
void vpanic(vnode_t *, const char *);
#ifdef DIAGNOSTIC
void
vpanic(vnode_t *vp, const char *msg)
{
vprint(NULL, vp);
panic("%s\n", msg);
}
#else
#define vpanic(vp, msg) /* nothing */
#endif
void
vn_init1(void)
{
vnode_cache = pool_cache_init(sizeof(struct vnode), 0, 0, 0, "vnodepl",
NULL, IPL_NONE, NULL, NULL, NULL);
KASSERT(vnode_cache != NULL);
/* Create deferred release thread. */
mutex_init(&vrele_lock, MUTEX_DEFAULT, IPL_NONE);
cv_init(&vrele_cv, "vrele");
if (kthread_create(PRI_VM, KTHREAD_MPSAFE, NULL, vrele_thread,
NULL, &vrele_lwp, "vrele"))
panic("fork vrele");
}
int
vfs_drainvnodes(long target, struct lwp *l)
{
while (numvnodes > target) {
vnode_t *vp;
mutex_enter(&vnode_free_list_lock);
vp = getcleanvnode();
if (vp == NULL)
return EBUSY; /* give up */
ungetnewvnode(vp);
}
return 0;
}
/*
* grab a vnode from freelist and clean it.
*/
vnode_t *
getcleanvnode(void)
{
vnode_t *vp;
vnodelst_t *listhd;
KASSERT(mutex_owned(&vnode_free_list_lock));
retry:
listhd = &vnode_free_list;
try_nextlist:
TAILQ_FOREACH(vp, listhd, v_freelist) {
/*
* It's safe to test v_usecount and v_iflag
* without holding the interlock here, since
* these vnodes should never appear on the
* lists.
*/
if (vp->v_usecount != 0) {
vpanic(vp, "free vnode isn't");
}
if ((vp->v_iflag & VI_CLEAN) != 0) {
vpanic(vp, "clean vnode on freelist");
}
if (vp->v_freelisthd != listhd) {
printf("vnode sez %p, listhd %p\n", vp->v_freelisthd, listhd);
vpanic(vp, "list head mismatch");
}
if (!mutex_tryenter(&vp->v_interlock))
continue;
/*
* Our lwp might hold the underlying vnode
* locked, so don't try to reclaim a VI_LAYER
* node if it's locked.
*/
if ((vp->v_iflag & VI_XLOCK) == 0 &&
((vp->v_iflag & VI_LAYER) == 0 || VOP_ISLOCKED(vp) == 0)) {
break;
}
mutex_exit(&vp->v_interlock);
}
if (vp == NULL) {
if (listhd == &vnode_free_list) {
listhd = &vnode_hold_list;
goto try_nextlist;
}
mutex_exit(&vnode_free_list_lock);
return NULL;
}
/* Remove it from the freelist. */
TAILQ_REMOVE(listhd, vp, v_freelist);
vp->v_freelisthd = NULL;
mutex_exit(&vnode_free_list_lock);
/*
* The vnode is still associated with a file system, so we must
* clean it out before reusing it. We need to add a reference
* before doing this. If the vnode gains another reference while
* being cleaned out then we lose - retry.
*/
vp->v_usecount++;
vclean(vp, DOCLOSE);
if (vp->v_usecount == 1) {
/* We're about to dirty it. */
vp->v_iflag &= ~VI_CLEAN;
mutex_exit(&vp->v_interlock);
if (vp->v_type == VBLK || vp->v_type == VCHR) {
spec_node_destroy(vp);
}
vp->v_type = VNON;
} else {
/*
* Don't return to freelist - the holder of the last
* reference will destroy it.
*/
KASSERT(vp->v_usecount > 1);
vp->v_usecount--;
mutex_exit(&vp->v_interlock);
mutex_enter(&vnode_free_list_lock);
goto retry;
}
if (vp->v_data != NULL || vp->v_uobj.uo_npages != 0 ||
!TAILQ_EMPTY(&vp->v_uobj.memq)) {
vpanic(vp, "cleaned vnode isn't");
}
if (vp->v_numoutput != 0) {
vpanic(vp, "clean vnode has pending I/O's");
}
if ((vp->v_iflag & VI_ONWORKLST) != 0) {
vpanic(vp, "clean vnode on syncer list");
}
return vp;
}
/*
* Mark a mount point as busy, and gain a new reference to it. Used to
* synchronize access and to delay unmounting.
*
* => Interlock is not released on failure.
* => If no interlock, the caller is expected to already hold a reference
* on the mount.
* => If interlocked, the interlock must prevent the last reference to
* the mount from disappearing.
*/
int
vfs_busy(struct mount *mp, const krw_t op, kmutex_t *interlock)
{
KASSERT(mp->mnt_refcnt > 0);
atomic_inc_uint(&mp->mnt_refcnt);
if (interlock != NULL) {
mutex_exit(interlock);
}
if (mp->mnt_writer == curlwp) {
mp->mnt_recursecnt++;
} else {
rw_enter(&mp->mnt_lock, op);
if (op == RW_WRITER) {
KASSERT(mp->mnt_writer == NULL);
mp->mnt_writer = curlwp;
}
}
if ((mp->mnt_iflag & IMNT_GONE) != 0) {
vfs_unbusy(mp, false);
if (interlock != NULL) {
mutex_enter(interlock);
}
return ENOENT;
}
return 0;
}
/*
* As vfs_busy(), but return immediately if the mount cannot be
* locked without waiting.
*/
int
vfs_trybusy(struct mount *mp, krw_t op, kmutex_t *interlock)
{
KASSERT(mp->mnt_refcnt > 0);
if (mp->mnt_writer == curlwp) {
mp->mnt_recursecnt++;
} else {
if (!rw_tryenter(&mp->mnt_lock, op)) {
return EBUSY;
}
if (op == RW_WRITER) {
KASSERT(mp->mnt_writer == NULL);
mp->mnt_writer = curlwp;
}
}
atomic_inc_uint(&mp->mnt_refcnt);
if ((mp->mnt_iflag & IMNT_GONE) != 0) {
vfs_unbusy(mp, false);
return ENOENT;
}
if (interlock != NULL) {
mutex_exit(interlock);
}
return 0;
}
/*
* Unlock a busy filesystem and drop reference to it. If 'keepref' is
* true, unlock but preserve the reference.
*/
void
vfs_unbusy(struct mount *mp, bool keepref)
{
KASSERT(mp->mnt_refcnt > 0);
if (mp->mnt_writer == curlwp) {
KASSERT(rw_write_held(&mp->mnt_lock));
if (mp->mnt_recursecnt != 0) {
mp->mnt_recursecnt--;
} else {
mp->mnt_writer = NULL;
rw_exit(&mp->mnt_lock);
}
} else {
rw_exit(&mp->mnt_lock);
}
if (!keepref) {
vfs_destroy(mp);
}
}
/*
* Lookup a filesystem type, and if found allocate and initialize
* a mount structure for it.
*
* Devname is usually updated by mount(8) after booting.
*/
int
vfs_rootmountalloc(const char *fstypename, const char *devname,
struct mount **mpp)
{
struct vfsops *vfsp = NULL;
struct mount *mp;
mutex_enter(&vfs_list_lock);
LIST_FOREACH(vfsp, &vfs_list, vfs_list)
if (!strncmp(vfsp->vfs_name, fstypename,
sizeof(mp->mnt_stat.f_fstypename)))
break;
if (vfsp == NULL) {
mutex_exit(&vfs_list_lock);
return (ENODEV);
}
vfsp->vfs_refcount++;
mutex_exit(&vfs_list_lock);
mp = kmem_zalloc(sizeof(*mp), KM_SLEEP);
if (mp == NULL)
return ENOMEM;
mp->mnt_refcnt = 1;
rw_init(&mp->mnt_lock);
mutex_init(&mp->mnt_renamelock, MUTEX_DEFAULT, IPL_NONE);
(void)vfs_busy(mp, RW_WRITER, NULL);
TAILQ_INIT(&mp->mnt_vnodelist);
mp->mnt_op = vfsp;
mp->mnt_flag = MNT_RDONLY;
mp->mnt_vnodecovered = NULL;
(void)strlcpy(mp->mnt_stat.f_fstypename, vfsp->vfs_name,
sizeof(mp->mnt_stat.f_fstypename));
mp->mnt_stat.f_mntonname[0] = '/';
mp->mnt_stat.f_mntonname[1] = '\0';
mp->mnt_stat.f_mntfromname[sizeof(mp->mnt_stat.f_mntfromname) - 1] =
'\0';
(void)copystr(devname, mp->mnt_stat.f_mntfromname,
sizeof(mp->mnt_stat.f_mntfromname) - 1, 0);
mount_initspecific(mp);
*mpp = mp;
return (0);
}
/*
* Routines having to do with the management of the vnode table.
*/
extern int (**dead_vnodeop_p)(void *);
/*
* Return the next vnode from the free list.
*/
int
getnewvnode(enum vtagtype tag, struct mount *mp, int (**vops)(void *),
vnode_t **vpp)
{
struct uvm_object *uobj;
static int toggle;
vnode_t *vp;
int error = 0, tryalloc;
try_again:
if (mp != NULL) {
/*
* Mark filesystem busy while we're creating a
* vnode. If unmount is in progress, this will
* wait; if the unmount succeeds (only if umount
* -f), this will return an error. If the
* unmount fails, we'll keep going afterwards.
*/
error = vfs_busy(mp, RW_READER, NULL);
if (error)
return error;
}
/*
* We must choose whether to allocate a new vnode or recycle an
* existing one. The criterion for allocating a new one is that
* the total number of vnodes is less than the number desired or
* there are no vnodes on either free list. Generally we only
* want to recycle vnodes that have no buffers associated with
* them, so we look first on the vnode_free_list. If it is empty,
* we next consider vnodes with referencing buffers on the
* vnode_hold_list. The toggle ensures that half the time we
* will use a buffer from the vnode_hold_list, and half the time
* we will allocate a new one unless the list has grown to twice
* the desired size. We are reticent to recycle vnodes from the
* vnode_hold_list because we will lose the identity of all its
* referencing buffers.
*/
vp = NULL;
mutex_enter(&vnode_free_list_lock);
toggle ^= 1;
if (numvnodes > 2 * desiredvnodes)
toggle = 0;
tryalloc = numvnodes < desiredvnodes ||
(TAILQ_FIRST(&vnode_free_list) == NULL &&
(TAILQ_FIRST(&vnode_hold_list) == NULL || toggle));
if (tryalloc) {
numvnodes++;
mutex_exit(&vnode_free_list_lock);
if ((vp = vnalloc(NULL)) == NULL) {
mutex_enter(&vnode_free_list_lock);
numvnodes--;
} else
vp->v_usecount = 1;
}
if (vp == NULL) {
vp = getcleanvnode();
if (vp == NULL) {
if (mp != NULL) {
vfs_unbusy(mp, false);
}
if (tryalloc) {
printf("WARNING: unable to allocate new "
"vnode, retrying...\n");
(void) tsleep(&lbolt, PRIBIO, "newvn", hz);
goto try_again;
}
tablefull("vnode", "increase kern.maxvnodes or NVNODE");
*vpp = 0;
return (ENFILE);
}
vp->v_iflag = 0;
vp->v_vflag = 0;
vp->v_uflag = 0;
vp->v_socket = NULL;
}
KASSERT(vp->v_usecount == 1);
KASSERT(vp->v_freelisthd == NULL);
KASSERT(LIST_EMPTY(&vp->v_nclist));
KASSERT(LIST_EMPTY(&vp->v_dnclist));
vp->v_type = VNON;
vp->v_vnlock = &vp->v_lock;
vp->v_tag = tag;
vp->v_op = vops;
insmntque(vp, mp);
*vpp = vp;
vp->v_data = 0;
/*
* initialize uvm_object within vnode.
*/
uobj = &vp->v_uobj;
KASSERT(uobj->pgops == &uvm_vnodeops);
KASSERT(uobj->uo_npages == 0);
KASSERT(TAILQ_FIRST(&uobj->memq) == NULL);
vp->v_size = vp->v_writesize = VSIZENOTSET;
if (mp != NULL) {
if ((mp->mnt_iflag & IMNT_MPSAFE) != 0)
vp->v_vflag |= VV_MPSAFE;
vfs_unbusy(mp, true);
}
return (0);
}
/*
* This is really just the reverse of getnewvnode(). Needed for
* VFS_VGET functions who may need to push back a vnode in case
* of a locking race.
*/
void
ungetnewvnode(vnode_t *vp)
{
KASSERT(vp->v_usecount == 1);
KASSERT(vp->v_data == NULL);
KASSERT(vp->v_freelisthd == NULL);
mutex_enter(&vp->v_interlock);
vp->v_iflag |= VI_CLEAN;
vrelel(vp, 0);
}
/*
* Allocate a new, uninitialized vnode. If 'mp' is non-NULL, this is a
* marker vnode and we are prepared to wait for the allocation.
*/
vnode_t *
vnalloc(struct mount *mp)
{
vnode_t *vp;
vp = pool_cache_get(vnode_cache, (mp != NULL ? PR_WAITOK : PR_NOWAIT));
if (vp == NULL) {
return NULL;
}
memset(vp, 0, sizeof(*vp));
UVM_OBJ_INIT(&vp->v_uobj, &uvm_vnodeops, 0);
cv_init(&vp->v_cv, "vnode");
/*
* done by memset() above.
* LIST_INIT(&vp->v_nclist);
* LIST_INIT(&vp->v_dnclist);
*/
if (mp != NULL) {
vp->v_mount = mp;
vp->v_type = VBAD;
vp->v_iflag = VI_MARKER;
} else {
rw_init(&vp->v_lock.vl_lock);
}
return vp;
}
/*
* Free an unused, unreferenced vnode.
*/
void
vnfree(vnode_t *vp)
{
KASSERT(vp->v_usecount == 0);
if ((vp->v_iflag & VI_MARKER) == 0) {
rw_destroy(&vp->v_lock.vl_lock);
mutex_enter(&vnode_free_list_lock);
numvnodes--;
mutex_exit(&vnode_free_list_lock);
}
UVM_OBJ_DESTROY(&vp->v_uobj);
cv_destroy(&vp->v_cv);
pool_cache_put(vnode_cache, vp);
}
/*
* Remove a vnode from its freelist.
*/
static inline void
vremfree(vnode_t *vp)
{
KASSERT(mutex_owned(&vp->v_interlock));
KASSERT(vp->v_usecount == 0);
/*
* Note that the reference count must not change until
* the vnode is removed.
*/
mutex_enter(&vnode_free_list_lock);
if (vp->v_holdcnt > 0) {
KASSERT(vp->v_freelisthd == &vnode_hold_list);
} else {
KASSERT(vp->v_freelisthd == &vnode_free_list);
}
TAILQ_REMOVE(vp->v_freelisthd, vp, v_freelist);
vp->v_freelisthd = NULL;
mutex_exit(&vnode_free_list_lock);
}
/*
* Move a vnode from one mount queue to another.
*/
static void
insmntque(vnode_t *vp, struct mount *mp)
{
struct mount *omp;
#ifdef DIAGNOSTIC
if ((mp != NULL) &&
(mp->mnt_iflag & IMNT_UNMOUNT) &&
!(mp->mnt_flag & MNT_SOFTDEP) &&
vp->v_tag != VT_VFS) {
panic("insmntque into dying filesystem");
}
#endif
mutex_enter(&mntvnode_lock);
/*
* Delete from old mount point vnode list, if on one.
*/
if ((omp = vp->v_mount) != NULL)
TAILQ_REMOVE(&vp->v_mount->mnt_vnodelist, vp, v_mntvnodes);
/*
* Insert into list of vnodes for the new mount point, if
* available. The caller must take a reference on the mount
* structure and donate to the vnode.
*/
if ((vp->v_mount = mp) != NULL)
TAILQ_INSERT_TAIL(&mp->mnt_vnodelist, vp, v_mntvnodes);
mutex_exit(&mntvnode_lock);
if (omp != NULL) {
/* Release reference to old mount. */
vfs_destroy(omp);
}
}
/*
* Create a vnode for a block device.
* Used for root filesystem and swap areas.
* Also used for memory file system special devices.
*/
int
bdevvp(dev_t dev, vnode_t **vpp)
{
return (getdevvp(dev, vpp, VBLK));
}
/*
* Create a vnode for a character device.
* Used for kernfs and some console handling.
*/
int
cdevvp(dev_t dev, vnode_t **vpp)
{
return (getdevvp(dev, vpp, VCHR));
}
/*
* Create a vnode for a device.
* Used by bdevvp (block device) for root file system etc.,
* and by cdevvp (character device) for console and kernfs.
*/
static int
getdevvp(dev_t dev, vnode_t **vpp, enum vtype type)
{
vnode_t *vp;
vnode_t *nvp;
int error;
if (dev == NODEV) {
*vpp = NULL;
return (0);
}
error = getnewvnode(VT_NON, NULL, spec_vnodeop_p, &nvp);
if (error) {
*vpp = NULL;
return (error);
}
vp = nvp;
vp->v_type = type;
vp->v_vflag |= VV_MPSAFE;
uvm_vnp_setsize(vp, 0);
spec_node_init(vp, dev);
*vpp = vp;
return (0);
}
/*
* Grab a particular vnode from the free list, increment its
* reference count and lock it. If the vnode lock bit is set the
* vnode is being eliminated in vgone. In that case, we can not
* grab the vnode, so the process is awakened when the transition is
* completed, and an error returned to indicate that the vnode is no
* longer usable (possibly having been changed to a new file system type).
*/
int
vget(vnode_t *vp, int flags)
{
int error;
KASSERT((vp->v_iflag & VI_MARKER) == 0);
if ((flags & LK_INTERLOCK) == 0)
mutex_enter(&vp->v_interlock);
/*
* Before adding a reference, we must remove the vnode
* from its freelist.
*/
if (vp->v_usecount == 0) {
vremfree(vp);
}
if (++vp->v_usecount == 0) {
vpanic(vp, "vget: usecount overflow");
}
/*
* If the vnode is in the process of being cleaned out for
* another use, we wait for the cleaning to finish and then
* return failure. Cleaning is determined by checking if
* the VI_XLOCK or VI_FREEING flags are set.
*/
if ((vp->v_iflag & (VI_XLOCK | VI_FREEING)) != 0) {
if ((flags & LK_NOWAIT) != 0) {
vrelel(vp, 0);
return EBUSY;
}
vwait(vp, VI_XLOCK | VI_FREEING);
vrelel(vp, 0);
return ENOENT;
}
if (flags & LK_TYPE_MASK) {
error = vn_lock(vp, flags | LK_INTERLOCK);
if (error != 0) {
vrele(vp);
}
return error;
}
mutex_exit(&vp->v_interlock);
return 0;
}
/*
* vput(), just unlock and vrele()
*/
void
vput(vnode_t *vp)
{
KASSERT((vp->v_iflag & VI_MARKER) == 0);
VOP_UNLOCK(vp, 0);
vrele(vp);
}
/*
* Vnode release. If reference count drops to zero, call inactive
* routine and either return to freelist or free to the pool.
*/
void
vrelel(vnode_t *vp, int flags)
{
bool recycle, defer;
int error;
KASSERT(mutex_owned(&vp->v_interlock));
KASSERT((vp->v_iflag & VI_MARKER) == 0);
KASSERT(vp->v_freelisthd == NULL);
if (vp->v_op == dead_vnodeop_p && (vp->v_iflag & VI_CLEAN) == 0) {
vpanic(vp, "dead but not clean");
}
/*
* If not the last reference, just drop the reference count
* and unlock.
*/
if (vp->v_usecount > 1) {
vp->v_usecount--;
vp->v_iflag |= VI_INACTREDO;
mutex_exit(&vp->v_interlock);
return;
}
if (vp->v_usecount <= 0 || vp->v_writecount != 0) {
vpanic(vp, "vput: bad ref count");
}
/*
* If not clean, deactivate the vnode, but preserve
* our reference across the call to VOP_INACTIVE().
*/
retry:
if ((vp->v_iflag & VI_CLEAN) == 0) {
recycle = false;
/*
* XXX This ugly block can be largely eliminated if
* locking is pushed down into the file systems.
*/
if (curlwp == uvm.pagedaemon_lwp) {
/* The pagedaemon can't wait around; defer. */
defer = true;
} else if (curlwp == vrele_lwp) {
/* We have to try harder. */
vp->v_iflag &= ~VI_INACTREDO;
error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK |
LK_RETRY);
if (error != 0) {
/* XXX */
vpanic(vp, "vrele: unable to lock %p");
}
defer = false;
} else if ((vp->v_iflag & VI_LAYER) != 0) {
/*
* Acquiring the stack's lock in vclean() even
* for an honest vput/vrele is dangerous because
* our caller may hold other vnode locks; defer.
*/
defer = true;
} else {
/* If we can't acquire the lock, then defer. */
vp->v_iflag &= ~VI_INACTREDO;
error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK |
LK_NOWAIT);
if (error != 0) {
defer = true;
mutex_enter(&vp->v_interlock);
} else {
defer = false;
}
}
if (defer) {
/*
* Defer reclaim to the kthread; it's not safe to
* clean it here. We donate it our last reference.
*/
KASSERT(mutex_owned(&vp->v_interlock));
KASSERT((vp->v_iflag & VI_INACTPEND) == 0);
vp->v_iflag |= VI_INACTPEND;
mutex_enter(&vrele_lock);
TAILQ_INSERT_TAIL(&vrele_list, vp, v_freelist);
if (++vrele_pending > (desiredvnodes >> 8))
cv_signal(&vrele_cv);
mutex_exit(&vrele_lock);
mutex_exit(&vp->v_interlock);
return;
}
#ifdef DIAGNOSTIC
if ((vp->v_type == VBLK || vp->v_type == VCHR) &&
vp->v_specnode != NULL && vp->v_specnode->sn_opencnt != 0) {
vprint("vrelel: missing VOP_CLOSE()", vp);
}
#endif
/*
* The vnode can gain another reference while being
* deactivated. If VOP_INACTIVE() indicates that
* the described file has been deleted, then recycle
* the vnode irrespective of additional references.
* Another thread may be waiting to re-use the on-disk
* inode.
*
* Note that VOP_INACTIVE() will drop the vnode lock.
*/
VOP_INACTIVE(vp, &recycle);
mutex_enter(&vp->v_interlock);
if (!recycle) {
if (vp->v_usecount > 1) {
vp->v_usecount--;
mutex_exit(&vp->v_interlock);
return;
}
/*
* If we grew another reference while
* VOP_INACTIVE() was underway, retry.
*/
if ((vp->v_iflag & VI_INACTREDO) != 0) {
goto retry;
}
}
/* Take care of space accounting. */
if (vp->v_iflag & VI_EXECMAP) {
atomic_add_int(&uvmexp.execpages,
-vp->v_uobj.uo_npages);
atomic_add_int(&uvmexp.filepages,
vp->v_uobj.uo_npages);
}
vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP|VI_WRMAP|VI_MAPPED);
vp->v_vflag &= ~VV_MAPPED;
/*
* Recycle the vnode if the file is now unused (unlinked),
* otherwise just free it.
*/
if (recycle) {
vclean(vp, DOCLOSE);
}
KASSERT(vp->v_usecount > 0);
}
if (--vp->v_usecount != 0) {
/* Gained another reference while being reclaimed. */
mutex_exit(&vp->v_interlock);
return;
}
if ((vp->v_iflag & VI_CLEAN) != 0) {
/*
* It's clean so destroy it. It isn't referenced
* anywhere since it has been reclaimed.
*/
KASSERT(vp->v_holdcnt == 0);
KASSERT(vp->v_writecount == 0);
mutex_exit(&vp->v_interlock);
insmntque(vp, NULL);
if (vp->v_type == VBLK || vp->v_type == VCHR) {
spec_node_destroy(vp);
}
vnfree(vp);
} else {
/*
* Otherwise, put it back onto the freelist. It
* can't be destroyed while still associated with
* a file system.
*/
mutex_enter(&vnode_free_list_lock);
if (vp->v_holdcnt > 0) {
vp->v_freelisthd = &vnode_hold_list;
} else {
vp->v_freelisthd = &vnode_free_list;
}
TAILQ_INSERT_TAIL(vp->v_freelisthd, vp, v_freelist);
mutex_exit(&vnode_free_list_lock);
mutex_exit(&vp->v_interlock);
}
}
void
vrele(vnode_t *vp)
{
KASSERT((vp->v_iflag & VI_MARKER) == 0);
mutex_enter(&vp->v_interlock);
vrelel(vp, 0);
}
static void
vrele_thread(void *cookie)
{
vnode_t *vp;
for (;;) {
mutex_enter(&vrele_lock);
while (TAILQ_EMPTY(&vrele_list)) {
cv_timedwait(&vrele_cv, &vrele_lock, hz);
}
vp = TAILQ_FIRST(&vrele_list);
TAILQ_REMOVE(&vrele_list, vp, v_freelist);
vrele_pending--;
mutex_exit(&vrele_lock);
/*
* If not the last reference, then ignore the vnode
* and look for more work.
*/
mutex_enter(&vp->v_interlock);
KASSERT((vp->v_iflag & VI_INACTPEND) != 0);
vp->v_iflag &= ~VI_INACTPEND;
if (vp->v_usecount > 1) {
vp->v_usecount--;
mutex_exit(&vp->v_interlock);
continue;
}
vrelel(vp, 0);
}
}
/*
* Page or buffer structure gets a reference.
* Called with v_interlock held.
*/
void
vholdl(vnode_t *vp)
{
KASSERT(mutex_owned(&vp->v_interlock));
KASSERT((vp->v_iflag & VI_MARKER) == 0);
if (vp->v_holdcnt++ == 0 && vp->v_usecount == 0) {
mutex_enter(&vnode_free_list_lock);
KASSERT(vp->v_freelisthd == &vnode_free_list);
TAILQ_REMOVE(vp->v_freelisthd, vp, v_freelist);
vp->v_freelisthd = &vnode_hold_list;
TAILQ_INSERT_TAIL(vp->v_freelisthd, vp, v_freelist);
mutex_exit(&vnode_free_list_lock);
}
}
/*
* Page or buffer structure frees a reference.
* Called with v_interlock held.
*/
void
holdrelel(vnode_t *vp)
{
KASSERT(mutex_owned(&vp->v_interlock));
KASSERT((vp->v_iflag & VI_MARKER) == 0);
if (vp->v_holdcnt <= 0) {
vpanic(vp, "holdrelel: holdcnt vp %p");
}
vp->v_holdcnt--;
if (vp->v_holdcnt == 0 && vp->v_usecount == 0) {
mutex_enter(&vnode_free_list_lock);
KASSERT(vp->v_freelisthd == &vnode_hold_list);
TAILQ_REMOVE(vp->v_freelisthd, vp, v_freelist);
vp->v_freelisthd = &vnode_free_list;
TAILQ_INSERT_TAIL(vp->v_freelisthd, vp, v_freelist);
mutex_exit(&vnode_free_list_lock);
}
}
/*
* Vnode reference, where a reference is already held by some other
* object (for example, a file structure).
*/
void
vref(vnode_t *vp)
{
KASSERT((vp->v_iflag & VI_MARKER) == 0);
mutex_enter(&vp->v_interlock);
if (vp->v_usecount <= 0) {
vpanic(vp, "vref used where vget required");
}
if (++vp->v_usecount == 0) {
vpanic(vp, "vref: usecount overflow");
}
mutex_exit(&vp->v_interlock);
}
/*
* Remove any vnodes in the vnode table belonging to mount point mp.
*
* If FORCECLOSE is not specified, there should not be any active ones,
* return error if any are found (nb: this is a user error, not a
* system error). If FORCECLOSE is specified, detach any active vnodes
* that are found.
*
* If WRITECLOSE is set, only flush out regular file vnodes open for
* writing.
*
* SKIPSYSTEM causes any vnodes marked V_SYSTEM to be skipped.
*/
#ifdef DEBUG
int busyprt = 0; /* print out busy vnodes */
struct ctldebug debug1 = { "busyprt", &busyprt };
#endif
static vnode_t *
vflushnext(vnode_t *mvp, int *when)
{
if (hardclock_ticks > *when) {
mutex_exit(&mntvnode_lock);
yield();
mutex_enter(&mntvnode_lock);
*when = hardclock_ticks + hz / 10;
}
return vunmark(mvp);
}
int
vflush(struct mount *mp, vnode_t *skipvp, int flags)
{
vnode_t *vp, *mvp;
int busy = 0, when = 0;
/* Allocate a marker vnode. */
if ((mvp = vnalloc(mp)) == NULL)
return (ENOMEM);
mutex_enter(&mntvnode_lock);
/*
* NOTE: not using the TAILQ_FOREACH here since in this loop vgone()
* and vclean() are called
*/
for (vp = TAILQ_FIRST(&mp->mnt_vnodelist); vp != NULL;
vp = vflushnext(mvp, &when)) {
vmark(mvp, vp);
if (vp->v_mount != mp || vismarker(vp))
continue;
/*
* Skip over a selected vnode.
*/
if (vp == skipvp)
continue;
mutex_enter(&vp->v_interlock);
/*
* Ignore clean but still referenced vnodes.
*/
if ((vp->v_iflag & VI_CLEAN) != 0) {
mutex_exit(&vp->v_interlock);
continue;
}
/*
* Skip over a vnodes marked VSYSTEM.
*/
if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) {
mutex_exit(&vp->v_interlock);
continue;
}
/*
* If WRITECLOSE is set, only flush out regular file
* vnodes open for writing.
*/
if ((flags & WRITECLOSE) &&
(vp->v_writecount == 0 || vp->v_type != VREG)) {
mutex_exit(&vp->v_interlock);
continue;
}
/*
* With v_usecount == 0, all we need to do is clear
* out the vnode data structures and we are done.
*/
if (vp->v_usecount == 0) {
mutex_exit(&mntvnode_lock);
vremfree(vp);
vp->v_usecount++;
vclean(vp, DOCLOSE);
vrelel(vp, 0);
mutex_enter(&mntvnode_lock);
continue;
}
/*
* If FORCECLOSE is set, forcibly close the vnode.
* For block or character devices, revert to an
* anonymous device. For all other files, just
* kill them.
*/
if (flags & FORCECLOSE) {
mutex_exit(&mntvnode_lock);
vp->v_usecount++;
if (vp->v_type != VBLK && vp->v_type != VCHR) {
vclean(vp, DOCLOSE);
vrelel(vp, 0);
} else {
vclean(vp, 0);
vp->v_op = spec_vnodeop_p; /* XXXSMP */
mutex_exit(&vp->v_interlock);
/*
* The vnode isn't clean, but still resides
* on the mount list. Remove it. XXX This
* is a bit dodgy.
*/
insmntque(vp, NULL);
vrele(vp);
}
mutex_enter(&mntvnode_lock);
continue;
}
#ifdef DEBUG
if (busyprt)
vprint("vflush: busy vnode", vp);
#endif
mutex_exit(&vp->v_interlock);
busy++;
}
mutex_exit(&mntvnode_lock);
vnfree(mvp);
if (busy)
return (EBUSY);
return (0);
}
/*
* Disassociate the underlying file system from a vnode.
*
* Must be called with the interlock held, and will return with it held.
*/
void
vclean(vnode_t *vp, int flags)
{
lwp_t *l = curlwp;
bool recycle, active;
int error;
KASSERT(mutex_owned(&vp->v_interlock));
KASSERT((vp->v_iflag & VI_MARKER) == 0);
KASSERT(vp->v_usecount != 0);
/* If cleaning is already in progress wait until done and return. */
if (vp->v_iflag & VI_XLOCK) {
vwait(vp, VI_XLOCK);
return;
}
/* If already clean, nothing to do. */
if ((vp->v_iflag & VI_CLEAN) != 0) {
return;
}
/*
* Prevent the vnode from being recycled or brought into use
* while we clean it out.
*/
vp->v_iflag |= VI_XLOCK;
if (vp->v_iflag & VI_EXECMAP) {
atomic_add_int(&uvmexp.execpages, -vp->v_uobj.uo_npages);
atomic_add_int(&uvmexp.filepages, vp->v_uobj.uo_npages);
}
vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP);
active = (vp->v_usecount > 1);
/* XXXAD should not lock vnode under layer */
VOP_LOCK(vp, LK_EXCLUSIVE | LK_INTERLOCK);
/*
* Clean out any cached data associated with the vnode.
* If purging an active vnode, it must be closed and
* deactivated before being reclaimed. Note that the
* VOP_INACTIVE will unlock the vnode.
*/
if (flags & DOCLOSE) {
error = vinvalbuf(vp, V_SAVE, NOCRED, l, 0, 0);
if (error != 0)
error = vinvalbuf(vp, 0, NOCRED, l, 0, 0);
KASSERT(error == 0);
KASSERT((vp->v_iflag & VI_ONWORKLST) == 0);
if (active && (vp->v_type == VBLK || vp->v_type == VCHR)) {
spec_node_revoke(vp);
}
}
if (active) {
VOP_INACTIVE(vp, &recycle);
} else {
/*
* Any other processes trying to obtain this lock must first
* wait for VI_XLOCK to clear, then call the new lock operation.
*/
VOP_UNLOCK(vp, 0);
}
/* Disassociate the underlying file system from the vnode. */
if (VOP_RECLAIM(vp)) {
vpanic(vp, "vclean: cannot reclaim");
}
KASSERT(vp->v_uobj.uo_npages == 0);
if (vp->v_type == VREG && vp->v_ractx != NULL) {
uvm_ra_freectx(vp->v_ractx);
vp->v_ractx = NULL;
}
cache_purge(vp);
/* Done with purge, notify sleepers of the grim news. */
vp->v_op = dead_vnodeop_p;
vp->v_tag = VT_NON;
mutex_enter(&vp->v_interlock);
vp->v_vnlock = &vp->v_lock;
KNOTE(&vp->v_klist, NOTE_REVOKE);
vp->v_iflag &= ~(VI_XLOCK | VI_FREEING);
vp->v_vflag &= ~VV_LOCKSWORK;
if ((flags & DOCLOSE) != 0) {
vp->v_iflag |= VI_CLEAN;
}
cv_broadcast(&vp->v_cv);
KASSERT((vp->v_iflag & VI_ONWORKLST) == 0);
}
/*
* Recycle an unused vnode to the front of the free list.
* Release the passed interlock if the vnode will be recycled.
*/
int
vrecycle(vnode_t *vp, kmutex_t *inter_lkp, struct lwp *l)
{
KASSERT((vp->v_iflag & VI_MARKER) == 0);
mutex_enter(&vp->v_interlock);
if (vp->v_usecount != 0) {
mutex_exit(&vp->v_interlock);
return (0);
}
if (inter_lkp)
mutex_exit(inter_lkp);
vremfree(vp);
vp->v_usecount++;
vclean(vp, DOCLOSE);
vrelel(vp, 0);
return (1);
}
/*
* Eliminate all activity associated with a vnode in preparation for
* reuse. Drops a reference from the vnode.
*/
void
vgone(vnode_t *vp)
{
mutex_enter(&vp->v_interlock);
vclean(vp, DOCLOSE);
vrelel(vp, 0);
}
/*
* Lookup a vnode by device number.
*/
int
vfinddev(dev_t dev, enum vtype type, vnode_t **vpp)
{
vnode_t *vp;
int rc = 0;
mutex_enter(&specfs_lock);
for (vp = specfs_hash[SPECHASH(dev)]; vp; vp = vp->v_specnext) {
if (dev != vp->v_rdev || type != vp->v_type)
continue;
*vpp = vp;
rc = 1;
break;
}
mutex_exit(&specfs_lock);
return (rc);
}
/*
* Revoke all the vnodes corresponding to the specified minor number
* range (endpoints inclusive) of the specified major.
*/
void
vdevgone(int maj, int minl, int minh, enum vtype type)
{
vnode_t *vp, **vpp;
dev_t dev;
int mn;
vp = NULL; /* XXX gcc */
mutex_enter(&specfs_lock);
for (mn = minl; mn <= minh; mn++) {
dev = makedev(maj, mn);
vpp = &specfs_hash[SPECHASH(dev)];
for (vp = *vpp; vp != NULL;) {
mutex_enter(&vp->v_interlock);
if ((vp->v_iflag & VI_CLEAN) != 0 ||
dev != vp->v_rdev || type != vp->v_type) {
mutex_exit(&vp->v_interlock);
vp = vp->v_specnext;
continue;
}
mutex_exit(&specfs_lock);
if (vget(vp, LK_INTERLOCK) == 0) {
VOP_REVOKE(vp, REVOKEALL);
vrele(vp);
}
mutex_enter(&specfs_lock);
vp = *vpp;
}
}
mutex_exit(&specfs_lock);
}
/*
* Calculate the total number of references to a special device.
*/
int
vcount(vnode_t *vp)
{
int count;
mutex_enter(&specfs_lock);
mutex_enter(&vp->v_interlock);
if (vp->v_specnode == NULL) {
count = vp->v_usecount - ((vp->v_iflag & VI_INACTPEND) != 0);
mutex_exit(&vp->v_interlock);
mutex_exit(&specfs_lock);
return (count);
}
mutex_exit(&vp->v_interlock);
count = vp->v_specnode->sn_dev->sd_opencnt;
mutex_exit(&specfs_lock);
return (count);
}
/*
* Eliminate all activity associated with the requested vnode
* and with all vnodes aliased to the requested vnode.
*/
void
vrevoke(vnode_t *vp)
{
vnode_t *vq, **vpp;
enum vtype type;
dev_t dev;
KASSERT(vp->v_usecount > 0);
mutex_enter(&vp->v_interlock);
if ((vp->v_iflag & VI_CLEAN) != 0) {
mutex_exit(&vp->v_interlock);
return;
} else {
dev = vp->v_rdev;
type = vp->v_type;
mutex_exit(&vp->v_interlock);
}
vpp = &specfs_hash[SPECHASH(dev)];
mutex_enter(&specfs_lock);
for (vq = *vpp; vq != NULL;) {
/* If clean or being cleaned, then ignore it. */
mutex_enter(&vq->v_interlock);
if ((vq->v_iflag & (VI_CLEAN | VI_XLOCK)) != 0 ||
vq->v_rdev != dev || vq->v_type != type) {
mutex_exit(&vq->v_interlock);
vq = vq->v_specnext;
continue;
}
mutex_exit(&specfs_lock);
if (vq->v_usecount == 0) {
vremfree(vq);
}
vq->v_usecount++;
vclean(vq, DOCLOSE);
vrelel(vq, 0);
mutex_enter(&specfs_lock);
vq = *vpp;
}
mutex_exit(&specfs_lock);
}
/*
* sysctl helper routine to return list of supported fstypes
*/
static int
sysctl_vfs_generic_fstypes(SYSCTLFN_ARGS)
{
char bf[sizeof(((struct statvfs *)NULL)->f_fstypename)];
char *where = oldp;
struct vfsops *v;
size_t needed, left, slen;
int error, first;
if (newp != NULL)
return (EPERM);
if (namelen != 0)
return (EINVAL);
first = 1;
error = 0;
needed = 0;
left = *oldlenp;
sysctl_unlock();
mutex_enter(&vfs_list_lock);
LIST_FOREACH(v, &vfs_list, vfs_list) {
if (where == NULL)
needed += strlen(v->vfs_name) + 1;
else {
memset(bf, 0, sizeof(bf));
if (first) {
strncpy(bf, v->vfs_name, sizeof(bf));
first = 0;
} else {
bf[0] = ' ';
strncpy(bf + 1, v->vfs_name, sizeof(bf) - 1);
}
bf[sizeof(bf)-1] = '\0';
slen = strlen(bf);
if (left < slen + 1)
break;
/* +1 to copy out the trailing NUL byte */
v->vfs_refcount++;
mutex_exit(&vfs_list_lock);
error = copyout(bf, where, slen + 1);
mutex_enter(&vfs_list_lock);
v->vfs_refcount--;
if (error)
break;
where += slen;
needed += slen;
left -= slen;
}
}
mutex_exit(&vfs_list_lock);
sysctl_relock();
*oldlenp = needed;
return (error);
}
/*
* Top level filesystem related information gathering.
*/
SYSCTL_SETUP(sysctl_vfs_setup, "sysctl vfs subtree setup")
{
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "vfs", NULL,
NULL, 0, NULL, 0,
CTL_VFS, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "generic",
SYSCTL_DESCR("Non-specific vfs related information"),
NULL, 0, NULL, 0,
CTL_VFS, VFS_GENERIC, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "usermount",
SYSCTL_DESCR("Whether unprivileged users may mount "
"filesystems"),
NULL, 0, &dovfsusermount, 0,
CTL_VFS, VFS_GENERIC, VFS_USERMOUNT, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_STRING, "fstypes",
SYSCTL_DESCR("List of file systems present"),
sysctl_vfs_generic_fstypes, 0, NULL, 0,
CTL_VFS, VFS_GENERIC, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "magiclinks",
SYSCTL_DESCR("Whether \"magic\" symlinks are expanded"),
NULL, 0, &vfs_magiclinks, 0,
CTL_VFS, VFS_GENERIC, VFS_MAGICLINKS, CTL_EOL);
}
int kinfo_vdebug = 1;
int kinfo_vgetfailed;
#define KINFO_VNODESLOP 10
/*
* Dump vnode list (via sysctl).
* Copyout address of vnode followed by vnode.
*/
/* ARGSUSED */
int
sysctl_kern_vnode(SYSCTLFN_ARGS)
{
char *where = oldp;
size_t *sizep = oldlenp;
struct mount *mp, *nmp;
vnode_t *vp, *mvp, vbuf;
char *bp = where, *savebp;
char *ewhere;
int error;
if (namelen != 0)
return (EOPNOTSUPP);
if (newp != NULL)
return (EPERM);
#define VPTRSZ sizeof(vnode_t *)
#define VNODESZ sizeof(vnode_t)
if (where == NULL) {
*sizep = (numvnodes + KINFO_VNODESLOP) * (VPTRSZ + VNODESZ);
return (0);
}
ewhere = where + *sizep;
sysctl_unlock();
mutex_enter(&mountlist_lock);
for (mp = CIRCLEQ_FIRST(&mountlist); mp != (void *)&mountlist;
mp = nmp) {
if (vfs_trybusy(mp, RW_READER, &mountlist_lock)) {
nmp = CIRCLEQ_NEXT(mp, mnt_list);
continue;
}
savebp = bp;
/* Allocate a marker vnode. */
if ((mvp = vnalloc(mp)) == NULL) {
sysctl_relock();
return (ENOMEM);
}
mutex_enter(&mntvnode_lock);
for (vp = TAILQ_FIRST(&mp->mnt_vnodelist); vp; vp = vunmark(mvp)) {
vmark(mvp, vp);
/*
* Check that the vp is still associated with
* this filesystem. RACE: could have been
* recycled onto the same filesystem.
*/
if (vp->v_mount != mp || vismarker(vp))
continue;
if (bp + VPTRSZ + VNODESZ > ewhere) {
(void)vunmark(mvp);
mutex_exit(&mntvnode_lock);
vnfree(mvp);
sysctl_relock();
*sizep = bp - where;
return (ENOMEM);
}
memcpy(&vbuf, vp, VNODESZ);
mutex_exit(&mntvnode_lock);
if ((error = copyout(vp, bp, VPTRSZ)) ||
(error = copyout(&vbuf, bp + VPTRSZ, VNODESZ))) {
mutex_enter(&mntvnode_lock);
(void)vunmark(mvp);
mutex_exit(&mntvnode_lock);
vnfree(mvp);
sysctl_relock();
return (error);
}
bp += VPTRSZ + VNODESZ;
mutex_enter(&mntvnode_lock);
}
mutex_exit(&mntvnode_lock);
mutex_enter(&mountlist_lock);
nmp = CIRCLEQ_NEXT(mp, mnt_list);
vfs_unbusy(mp, false);
vnfree(mvp);
}
mutex_exit(&mountlist_lock);
sysctl_relock();
*sizep = bp - where;
return (0);
}
/*
* Remove clean vnodes from a mountpoint's vnode list.
*/
void
vfs_scrubvnlist(struct mount *mp)
{
vnode_t *vp, *nvp;
retry:
mutex_enter(&mntvnode_lock);
for (vp = TAILQ_FIRST(&mp->mnt_vnodelist); vp; vp = nvp) {
nvp = TAILQ_NEXT(vp, v_mntvnodes);
mutex_enter(&vp->v_interlock);
if ((vp->v_iflag & VI_CLEAN) != 0) {
TAILQ_REMOVE(&mp->mnt_vnodelist, vp, v_mntvnodes);
vp->v_mount = NULL;
mutex_exit(&mntvnode_lock);
mutex_exit(&vp->v_interlock);
vfs_destroy(mp);
goto retry;
}
mutex_exit(&vp->v_interlock);
}
mutex_exit(&mntvnode_lock);
}
/*
* Check to see if a filesystem is mounted on a block device.
*/
int
vfs_mountedon(vnode_t *vp)
{
vnode_t *vq;
int error = 0;
if (vp->v_type != VBLK)
return ENOTBLK;
if (vp->v_specmountpoint != NULL)
return (EBUSY);
mutex_enter(&specfs_lock);
for (vq = specfs_hash[SPECHASH(vp->v_rdev)]; vq != NULL;
vq = vq->v_specnext) {
if (vq->v_rdev != vp->v_rdev || vq->v_type != vp->v_type)
continue;
if (vq->v_specmountpoint != NULL) {
error = EBUSY;
break;
}
}
mutex_exit(&specfs_lock);
return (error);
}
/*
* Unmount all file systems.
* We traverse the list in reverse order under the assumption that doing so
* will avoid needing to worry about dependencies.
*/
void
vfs_unmountall(struct lwp *l)
{
struct mount *mp, *nmp;
int allerror, error;
printf("unmounting file systems...");
for (allerror = 0, mp = CIRCLEQ_LAST(&mountlist);
!CIRCLEQ_EMPTY(&mountlist);
mp = nmp) {
nmp = CIRCLEQ_PREV(mp, mnt_list);
#ifdef DEBUG
printf("\nunmounting %s (%s)...",
mp->mnt_stat.f_mntonname, mp->mnt_stat.f_mntfromname);
#endif
/*
* XXX Freeze syncer. Must do this before locking the
* mount point. See dounmount() for details.
*/
mutex_enter(&syncer_mutex);
if (vfs_busy(mp, RW_WRITER, NULL)) {
mutex_exit(&syncer_mutex);
continue;
}
if ((error = dounmount(mp, MNT_FORCE, l)) != 0) {
printf("unmount of %s failed with error %d\n",
mp->mnt_stat.f_mntonname, error);
allerror = 1;
}
}
printf(" done\n");
if (allerror)
printf("WARNING: some file systems would not unmount\n");
}
/*
* Sync and unmount file systems before shutting down.
*/
void
vfs_shutdown(void)
{
struct lwp *l;
/* XXX we're certainly not running in lwp0's context! */
l = curlwp;
if (l == NULL)
l = &lwp0;
printf("syncing disks... ");
/* remove user processes from run queue */
suspendsched();
(void) spl0();
/* avoid coming back this way again if we panic. */
doing_shutdown = 1;
sys_sync(l, NULL, NULL);
/* Wait for sync to finish. */
if (buf_syncwait() != 0) {
#if defined(DDB) && defined(DEBUG_HALT_BUSY)
Debugger();
#endif
printf("giving up\n");
return;
} else
printf("done\n");
/*
* If we've panic'd, don't make the situation potentially
* worse by unmounting the file systems.
*/
if (panicstr != NULL)
return;
/* Release inodes held by texts before update. */
#ifdef notdef
vnshutdown();
#endif
/* Unmount file systems. */
vfs_unmountall(l);
}
/*
* Mount the root file system. If the operator didn't specify a
* file system to use, try all possible file systems until one
* succeeds.
*/
int
vfs_mountroot(void)
{
struct vfsops *v;
int error = ENODEV;
if (root_device == NULL)
panic("vfs_mountroot: root device unknown");
switch (device_class(root_device)) {
case DV_IFNET:
if (rootdev != NODEV)
panic("vfs_mountroot: rootdev set for DV_IFNET "
"(0x%08x -> %d,%d)", rootdev,
major(rootdev), minor(rootdev));
break;
case DV_DISK:
if (rootdev == NODEV)
panic("vfs_mountroot: rootdev not set for DV_DISK");
if (bdevvp(rootdev, &rootvp))
panic("vfs_mountroot: can't get vnode for rootdev");
error = VOP_OPEN(rootvp, FREAD, FSCRED);
if (error) {
printf("vfs_mountroot: can't open root device\n");
return (error);
}
break;
default:
printf("%s: inappropriate for root file system\n",
device_xname(root_device));
return (ENODEV);
}
/*
* If user specified a file system, use it.
*/
if (mountroot != NULL) {
error = (*mountroot)();
goto done;
}
/*
* Try each file system currently configured into the kernel.
*/
mutex_enter(&vfs_list_lock);
LIST_FOREACH(v, &vfs_list, vfs_list) {
if (v->vfs_mountroot == NULL)
continue;
#ifdef DEBUG
aprint_normal("mountroot: trying %s...\n", v->vfs_name);
#endif
v->vfs_refcount++;
mutex_exit(&vfs_list_lock);
error = (*v->vfs_mountroot)();
mutex_enter(&vfs_list_lock);
v->vfs_refcount--;
if (!error) {
aprint_normal("root file system type: %s\n",
v->vfs_name);
break;
}
}
mutex_exit(&vfs_list_lock);
if (v == NULL) {
printf("no file system for %s", device_xname(root_device));
if (device_class(root_device) == DV_DISK)
printf(" (dev 0x%x)", rootdev);
printf("\n");
error = EFTYPE;
}
done:
if (error && device_class(root_device) == DV_DISK) {
VOP_CLOSE(rootvp, FREAD, FSCRED);
vrele(rootvp);
}
return (error);
}
/*
* Sham lock manager for vnodes. This is a temporary measure.
*/
int
vlockmgr(struct vnlock *vl, int flags)
{
KASSERT((flags & ~(LK_CANRECURSE | LK_NOWAIT | LK_TYPE_MASK)) == 0);
switch (flags & LK_TYPE_MASK) {
case LK_SHARED:
if (rw_tryenter(&vl->vl_lock, RW_READER)) {
return 0;
}
if ((flags & LK_NOWAIT) != 0) {
return EBUSY;
}
rw_enter(&vl->vl_lock, RW_READER);
return 0;
case LK_EXCLUSIVE:
if (rw_tryenter(&vl->vl_lock, RW_WRITER)) {
return 0;
}
if ((vl->vl_canrecurse || (flags & LK_CANRECURSE) != 0) &&
rw_write_held(&vl->vl_lock)) {
vl->vl_recursecnt++;
return 0;
}
if ((flags & LK_NOWAIT) != 0) {
return EBUSY;
}
rw_enter(&vl->vl_lock, RW_WRITER);
return 0;
case LK_RELEASE:
if (vl->vl_recursecnt != 0) {
KASSERT(rw_write_held(&vl->vl_lock));
vl->vl_recursecnt--;
return 0;
}
rw_exit(&vl->vl_lock);
return 0;
default:
panic("vlockmgr: flags %x", flags);
}
}
int
vlockstatus(struct vnlock *vl)
{
if (rw_write_held(&vl->vl_lock)) {
return LK_EXCLUSIVE;
}
if (rw_read_held(&vl->vl_lock)) {
return LK_SHARED;
}
return 0;
}
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