/
vfs_subr.c
2344 lines (2082 loc) · 52.4 KB
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vfs_subr.c
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/* $OpenBSD: vfs_subr.c,v 1.299 2020/01/20 23:21:55 claudio Exp $ */
/* $NetBSD: vfs_subr.c,v 1.53 1996/04/22 01:39:13 christos Exp $ */
/*
* 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
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <sys/mount.h>
#include <sys/time.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#include <sys/lock.h>
#include <sys/lockf.h>
#include <sys/stat.h>
#include <sys/acct.h>
#include <sys/namei.h>
#include <sys/ucred.h>
#include <sys/buf.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/syscallargs.h>
#include <sys/pool.h>
#include <sys/tree.h>
#include <sys/specdev.h>
#include <sys/atomic.h>
#include <netinet/in.h>
#include <uvm/uvm_extern.h>
#include <uvm/uvm_vnode.h>
#include "softraid.h"
void sr_quiesce(void);
enum vtype iftovt_tab[16] = {
VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
};
int vttoif_tab[9] = {
0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
S_IFSOCK, S_IFIFO, S_IFMT,
};
int prtactive = 0; /* 1 => print out reclaim of active vnodes */
int suid_clear = 1; /* 1 => clear SUID / SGID on owner change */
/*
* Insq/Remq for the vnode usage lists.
*/
#define bufinsvn(bp, dp) LIST_INSERT_HEAD(dp, bp, b_vnbufs)
#define bufremvn(bp) { \
LIST_REMOVE(bp, b_vnbufs); \
LIST_NEXT(bp, b_vnbufs) = NOLIST; \
}
struct freelst vnode_hold_list; /* list of vnodes referencing buffers */
struct freelst vnode_free_list; /* vnode free list */
struct mntlist mountlist; /* mounted filesystem list */
void vclean(struct vnode *, int, struct proc *);
void insmntque(struct vnode *, struct mount *);
int getdevvp(dev_t, struct vnode **, enum vtype);
int vfs_hang_addrlist(struct mount *, struct netexport *,
struct export_args *);
int vfs_free_netcred(struct radix_node *, void *, u_int);
void vfs_free_addrlist(struct netexport *);
void vputonfreelist(struct vnode *);
int vflush_vnode(struct vnode *, void *);
int maxvnodes;
void vfs_unmountall(void);
#ifdef DEBUG
void printlockedvnodes(void);
#endif
struct pool vnode_pool;
struct pool uvm_vnode_pool;
static inline int rb_buf_compare(const struct buf *b1, const struct buf *b2);
RBT_GENERATE(buf_rb_bufs, buf, b_rbbufs, rb_buf_compare);
static inline int
rb_buf_compare(const struct buf *b1, const struct buf *b2)
{
if (b1->b_lblkno < b2->b_lblkno)
return(-1);
if (b1->b_lblkno > b2->b_lblkno)
return(1);
return(0);
}
/*
* Initialize the vnode management data structures.
*/
void
vntblinit(void)
{
/* buffer cache may need a vnode for each buffer */
maxvnodes = 2 * initialvnodes;
pool_init(&vnode_pool, sizeof(struct vnode), 0, IPL_NONE,
PR_WAITOK, "vnodes", NULL);
pool_init(&uvm_vnode_pool, sizeof(struct uvm_vnode), 0, IPL_NONE,
PR_WAITOK, "uvmvnodes", NULL);
TAILQ_INIT(&vnode_hold_list);
TAILQ_INIT(&vnode_free_list);
TAILQ_INIT(&mountlist);
/*
* Initialize the filesystem syncer.
*/
vn_initialize_syncerd();
#ifdef NFSSERVER
rn_init(sizeof(struct sockaddr_in));
#endif /* NFSSERVER */
}
/*
* Allocate a mount point.
*
* The returned mount point is marked as busy.
*/
struct mount *
vfs_mount_alloc(struct vnode *vp, struct vfsconf *vfsp)
{
struct mount *mp;
mp = malloc(sizeof(*mp), M_MOUNT, M_WAITOK|M_ZERO);
rw_init_flags(&mp->mnt_lock, "vfslock", RWL_IS_VNODE);
(void)vfs_busy(mp, VB_READ|VB_NOWAIT);
TAILQ_INIT(&mp->mnt_vnodelist);
mp->mnt_vnodecovered = vp;
atomic_inc_int(&vfsp->vfc_refcount);
mp->mnt_vfc = vfsp;
mp->mnt_op = vfsp->vfc_vfsops;
mp->mnt_flag = vfsp->vfc_flags;
strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
return (mp);
}
/*
* Release a mount point.
*/
void
vfs_mount_free(struct mount *mp)
{
atomic_dec_int(&mp->mnt_vfc->vfc_refcount);
free(mp, M_MOUNT, sizeof(*mp));
}
/*
* Mark a mount point as busy. Used to synchronize access and to delay
* unmounting.
*
* Default behaviour is to attempt getting a READ lock and in case of an
* ongoing unmount, to wait for it to finish and then return failure.
*/
int
vfs_busy(struct mount *mp, int flags)
{
int rwflags = 0;
if (flags & VB_WRITE)
rwflags |= RW_WRITE;
else
rwflags |= RW_READ;
if (flags & VB_WAIT)
rwflags |= RW_SLEEPFAIL;
else
rwflags |= RW_NOSLEEP;
#ifdef WITNESS
if (flags & VB_DUPOK)
rwflags |= RW_DUPOK;
#endif
if (rw_enter(&mp->mnt_lock, rwflags))
return (EBUSY);
return (0);
}
/*
* Free a busy file system
*/
void
vfs_unbusy(struct mount *mp)
{
rw_exit(&mp->mnt_lock);
}
int
vfs_isbusy(struct mount *mp)
{
if (RWLOCK_OWNER(&mp->mnt_lock) > 0)
return (1);
else
return (0);
}
/*
* 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(char *fstypename, char *devname, struct mount **mpp)
{
struct vfsconf *vfsp;
struct mount *mp;
vfsp = vfs_byname(fstypename);
if (vfsp == NULL)
return (ENODEV);
mp = vfs_mount_alloc(NULLVP, vfsp);
mp->mnt_flag |= MNT_RDONLY;
mp->mnt_stat.f_mntonname[0] = '/';
copystr(devname, mp->mnt_stat.f_mntfromname, MNAMELEN, 0);
copystr(devname, mp->mnt_stat.f_mntfromspec, MNAMELEN, 0);
*mpp = mp;
return (0);
}
/*
* Lookup a mount point by filesystem identifier.
*/
struct mount *
vfs_getvfs(fsid_t *fsid)
{
struct mount *mp;
TAILQ_FOREACH(mp, &mountlist, mnt_list) {
if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
return (mp);
}
}
return (NULL);
}
/*
* Get a new unique fsid
*/
void
vfs_getnewfsid(struct mount *mp)
{
static u_short xxxfs_mntid;
fsid_t tfsid;
int mtype;
mtype = mp->mnt_vfc->vfc_typenum;
mp->mnt_stat.f_fsid.val[0] = makedev(nblkdev + mtype, 0);
mp->mnt_stat.f_fsid.val[1] = mtype;
if (xxxfs_mntid == 0)
++xxxfs_mntid;
tfsid.val[0] = makedev(nblkdev + mtype, xxxfs_mntid);
tfsid.val[1] = mtype;
if (!TAILQ_EMPTY(&mountlist)) {
while (vfs_getvfs(&tfsid)) {
tfsid.val[0]++;
xxxfs_mntid++;
}
}
mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
}
/*
* Set vnode attributes to VNOVAL
*/
void
vattr_null(struct vattr *vap)
{
vap->va_type = VNON;
/*
* Don't get fancy: u_quad_t = u_int = VNOVAL leaves the u_quad_t
* with 2^31-1 instead of 2^64-1. Just write'm out and let
* the compiler do its job.
*/
vap->va_mode = VNOVAL;
vap->va_nlink = VNOVAL;
vap->va_uid = VNOVAL;
vap->va_gid = VNOVAL;
vap->va_fsid = VNOVAL;
vap->va_fileid = VNOVAL;
vap->va_size = VNOVAL;
vap->va_blocksize = VNOVAL;
vap->va_atime.tv_sec = VNOVAL;
vap->va_atime.tv_nsec = VNOVAL;
vap->va_mtime.tv_sec = VNOVAL;
vap->va_mtime.tv_nsec = VNOVAL;
vap->va_ctime.tv_sec = VNOVAL;
vap->va_ctime.tv_nsec = VNOVAL;
vap->va_gen = VNOVAL;
vap->va_flags = VNOVAL;
vap->va_rdev = VNOVAL;
vap->va_bytes = VNOVAL;
vap->va_filerev = VNOVAL;
vap->va_vaflags = 0;
}
/*
* Routines having to do with the management of the vnode table.
*/
long numvnodes;
/*
* Return the next vnode from the free list.
*/
int
getnewvnode(enum vtagtype tag, struct mount *mp, const struct vops *vops,
struct vnode **vpp)
{
struct proc *p = curproc;
struct freelst *listhd;
static int toggle;
struct vnode *vp;
int s;
/*
* allow maxvnodes to increase if the buffer cache itself
* is big enough to justify it. (we don't shrink it ever)
*/
maxvnodes = maxvnodes < bcstats.numbufs ? bcstats.numbufs
: maxvnodes;
/*
* 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.
*/
toggle ^= 1;
if (numvnodes / 2 > maxvnodes)
toggle = 0;
s = splbio();
if ((numvnodes < maxvnodes) ||
((TAILQ_FIRST(listhd = &vnode_free_list) == NULL) &&
((TAILQ_FIRST(listhd = &vnode_hold_list) == NULL) || toggle))) {
splx(s);
vp = pool_get(&vnode_pool, PR_WAITOK | PR_ZERO);
vp->v_uvm = pool_get(&uvm_vnode_pool, PR_WAITOK | PR_ZERO);
vp->v_uvm->u_vnode = vp;
RBT_INIT(buf_rb_bufs, &vp->v_bufs_tree);
cache_tree_init(&vp->v_nc_tree);
TAILQ_INIT(&vp->v_cache_dst);
numvnodes++;
} else {
TAILQ_FOREACH(vp, listhd, v_freelist) {
if (VOP_ISLOCKED(vp) == 0)
break;
}
/*
* Unless this is a bad time of the month, at most
* the first NCPUS items on the free list are
* locked, so this is close enough to being empty.
*/
if (vp == NULL) {
splx(s);
tablefull("vnode");
*vpp = 0;
return (ENFILE);
}
#ifdef DIAGNOSTIC
if (vp->v_usecount) {
vprint("free vnode", vp);
panic("free vnode isn't");
}
#endif
TAILQ_REMOVE(listhd, vp, v_freelist);
vp->v_bioflag &= ~VBIOONFREELIST;
splx(s);
if (vp->v_type != VBAD)
vgonel(vp, p);
#ifdef DIAGNOSTIC
if (vp->v_data) {
vprint("cleaned vnode", vp);
panic("cleaned vnode isn't");
}
s = splbio();
if (vp->v_numoutput)
panic("Clean vnode has pending I/O's");
splx(s);
#endif
vp->v_flag = 0;
vp->v_socket = 0;
}
cache_purge(vp);
vp->v_type = VNON;
vp->v_tag = tag;
vp->v_op = vops;
insmntque(vp, mp);
*vpp = vp;
vp->v_usecount = 1;
vp->v_data = 0;
return (0);
}
/*
* Move a vnode from one mount queue to another.
*/
void
insmntque(struct vnode *vp, struct mount *mp)
{
/*
* Delete from old mount point vnode list, if on one.
*/
if (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.
*/
if ((vp->v_mount = mp) != NULL)
TAILQ_INSERT_TAIL(&mp->mnt_vnodelist, vp, v_mntvnodes);
}
/*
* Create a vnode for a block device.
* Used for root filesystem, argdev, and swap areas.
* Also used for memory file system special devices.
*/
int
bdevvp(dev_t dev, struct vnode **vpp)
{
return (getdevvp(dev, vpp, VBLK));
}
/*
* Create a vnode for a character device.
* Used for console handling.
*/
int
cdevvp(dev_t dev, struct vnode **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.
*/
int
getdevvp(dev_t dev, struct vnode **vpp, enum vtype type)
{
struct vnode *vp;
struct vnode *nvp;
int error;
if (dev == NODEV) {
*vpp = NULLVP;
return (0);
}
error = getnewvnode(VT_NON, NULL, &spec_vops, &nvp);
if (error) {
*vpp = NULLVP;
return (error);
}
vp = nvp;
vp->v_type = type;
if ((nvp = checkalias(vp, dev, NULL)) != 0) {
vput(vp);
vp = nvp;
}
if (vp->v_type == VCHR && cdevsw[major(vp->v_rdev)].d_type == D_TTY)
vp->v_flag |= VISTTY;
*vpp = vp;
return (0);
}
/*
* Check to see if the new vnode represents a special device
* for which we already have a vnode (either because of
* bdevvp() or because of a different vnode representing
* the same block device). If such an alias exists, deallocate
* the existing contents and return the aliased vnode. The
* caller is responsible for filling it with its new contents.
*/
struct vnode *
checkalias(struct vnode *nvp, dev_t nvp_rdev, struct mount *mp)
{
struct proc *p = curproc;
struct vnode *vp;
struct vnodechain *vchain;
if (nvp->v_type != VBLK && nvp->v_type != VCHR)
return (NULLVP);
vchain = &speclisth[SPECHASH(nvp_rdev)];
loop:
SLIST_FOREACH(vp, vchain, v_specnext) {
if (nvp_rdev != vp->v_rdev || nvp->v_type != vp->v_type) {
continue;
}
/*
* Alias, but not in use, so flush it out.
*/
if (vp->v_usecount == 0) {
vgonel(vp, p);
goto loop;
}
if (vget(vp, LK_EXCLUSIVE)) {
goto loop;
}
break;
}
/*
* Common case is actually in the if statement
*/
if (vp == NULL || !(vp->v_tag == VT_NON && vp->v_type == VBLK)) {
nvp->v_specinfo = malloc(sizeof(struct specinfo), M_VNODE,
M_WAITOK);
nvp->v_rdev = nvp_rdev;
nvp->v_hashchain = vchain;
nvp->v_specmountpoint = NULL;
nvp->v_speclockf = NULL;
nvp->v_specbitmap = NULL;
if (nvp->v_type == VCHR &&
(cdevsw[major(nvp_rdev)].d_flags & D_CLONE) &&
(minor(nvp_rdev) >> CLONE_SHIFT == 0)) {
if (vp != NULLVP)
nvp->v_specbitmap = vp->v_specbitmap;
else
nvp->v_specbitmap = malloc(CLONE_MAPSZ,
M_VNODE, M_WAITOK | M_ZERO);
}
SLIST_INSERT_HEAD(vchain, nvp, v_specnext);
if (vp != NULLVP) {
nvp->v_flag |= VALIASED;
vp->v_flag |= VALIASED;
vput(vp);
}
return (NULLVP);
}
/*
* This code is the uncommon case. It is called in case
* we found an alias that was VT_NON && vtype of VBLK
* This means we found a block device that was created
* using bdevvp.
* An example of such a vnode is the root partition device vnode
* created in ffs_mountroot.
*
* The vnodes created by bdevvp should not be aliased (why?).
*/
VOP_UNLOCK(vp);
vclean(vp, 0, p);
vp->v_op = nvp->v_op;
vp->v_tag = nvp->v_tag;
nvp->v_type = VNON;
insmntque(vp, mp);
return (vp);
}
/*
* 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
* cannot grab it, so the process is awakened when the
* transition is completed, and an error code is returned to
* indicate that the vnode is no longer usable, possibly
* having been changed to a new file system type.
*/
int
vget(struct vnode *vp, int flags)
{
int error, s, onfreelist;
/*
* 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 that
* the VXLOCK flag is set.
*/
if (vp->v_flag & VXLOCK) {
if (flags & LK_NOWAIT) {
return (EBUSY);
}
vp->v_flag |= VXWANT;
tsleep_nsec(vp, PINOD, "vget", INFSLP);
return (ENOENT);
}
onfreelist = vp->v_bioflag & VBIOONFREELIST;
if (vp->v_usecount == 0 && onfreelist) {
s = splbio();
if (vp->v_holdcnt > 0)
TAILQ_REMOVE(&vnode_hold_list, vp, v_freelist);
else
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
vp->v_bioflag &= ~VBIOONFREELIST;
splx(s);
}
vp->v_usecount++;
if (flags & LK_TYPE_MASK) {
if ((error = vn_lock(vp, flags)) != 0) {
vp->v_usecount--;
if (vp->v_usecount == 0 && onfreelist)
vputonfreelist(vp);
}
return (error);
}
return (0);
}
/* Vnode reference. */
void
vref(struct vnode *vp)
{
#ifdef DIAGNOSTIC
if (vp->v_usecount == 0)
panic("vref used where vget required");
if (vp->v_type == VNON)
panic("vref on a VNON vnode");
#endif
vp->v_usecount++;
}
void
vputonfreelist(struct vnode *vp)
{
int s;
struct freelst *lst;
s = splbio();
#ifdef DIAGNOSTIC
if (vp->v_usecount != 0)
panic("Use count is not zero!");
if (vp->v_lockcount != 0)
panic("%s: lock count is not zero", __func__);
if (vp->v_bioflag & VBIOONFREELIST) {
vprint("vnode already on free list: ", vp);
panic("vnode already on free list");
}
#endif
vp->v_bioflag |= VBIOONFREELIST;
vp->v_bioflag &= ~VBIOERROR;
if (vp->v_holdcnt > 0)
lst = &vnode_hold_list;
else
lst = &vnode_free_list;
if (vp->v_type == VBAD)
TAILQ_INSERT_HEAD(lst, vp, v_freelist);
else
TAILQ_INSERT_TAIL(lst, vp, v_freelist);
splx(s);
}
/*
* vput(), just unlock and vrele()
*/
void
vput(struct vnode *vp)
{
struct proc *p = curproc;
#ifdef DIAGNOSTIC
if (vp == NULL)
panic("vput: null vp");
#endif
#ifdef DIAGNOSTIC
if (vp->v_usecount == 0) {
vprint("vput: bad ref count", vp);
panic("vput: ref cnt");
}
#endif
vp->v_usecount--;
KASSERT(vp->v_usecount > 0 || vp->v_uvcount == 0);
if (vp->v_usecount > 0) {
VOP_UNLOCK(vp);
return;
}
#ifdef DIAGNOSTIC
if (vp->v_writecount != 0) {
vprint("vput: bad writecount", vp);
panic("vput: v_writecount != 0");
}
#endif
VOP_INACTIVE(vp, p);
if (vp->v_usecount == 0 && !(vp->v_bioflag & VBIOONFREELIST))
vputonfreelist(vp);
}
/*
* Vnode release - use for active VNODES.
* If count drops to zero, call inactive routine and return to freelist.
* Returns 0 if it did not sleep.
*/
int
vrele(struct vnode *vp)
{
struct proc *p = curproc;
#ifdef DIAGNOSTIC
if (vp == NULL)
panic("vrele: null vp");
#endif
#ifdef DIAGNOSTIC
if (vp->v_usecount == 0) {
vprint("vrele: bad ref count", vp);
panic("vrele: ref cnt");
}
#endif
vp->v_usecount--;
if (vp->v_usecount > 0) {
return (0);
}
#ifdef DIAGNOSTIC
if (vp->v_writecount != 0) {
vprint("vrele: bad writecount", vp);
panic("vrele: v_writecount != 0");
}
#endif
if (vn_lock(vp, LK_EXCLUSIVE)) {
#ifdef DIAGNOSTIC
vprint("vrele: cannot lock", vp);
#endif
return (1);
}
VOP_INACTIVE(vp, p);
if (vp->v_usecount == 0 && !(vp->v_bioflag & VBIOONFREELIST))
vputonfreelist(vp);
return (1);
}
/* Page or buffer structure gets a reference. */
void
vhold(struct vnode *vp)
{
/*
* If it is on the freelist and the hold count is currently
* zero, move it to the hold list.
*/
if ((vp->v_bioflag & VBIOONFREELIST) &&
vp->v_holdcnt == 0 && vp->v_usecount == 0) {
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
TAILQ_INSERT_TAIL(&vnode_hold_list, vp, v_freelist);
}
vp->v_holdcnt++;
}
/* Lose interest in a vnode. */
void
vdrop(struct vnode *vp)
{
#ifdef DIAGNOSTIC
if (vp->v_holdcnt == 0)
panic("vdrop: zero holdcnt");
#endif
vp->v_holdcnt--;
/*
* If it is on the holdlist and the hold count drops to
* zero, move it to the free list.
*/
if ((vp->v_bioflag & VBIOONFREELIST) &&
vp->v_holdcnt == 0 && vp->v_usecount == 0) {
TAILQ_REMOVE(&vnode_hold_list, vp, v_freelist);
TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
}
}
/*
* Remove any vnodes in the vnode table belonging to mount point mp.
*
* If MNT_NOFORCE is 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 MNT_FORCE is specified, detach any active vnodes
* that are found.
*/
#ifdef DEBUG
int busyprt = 0; /* print out busy vnodes */
struct ctldebug debug1 = { "busyprt", &busyprt };
#endif
int
vfs_mount_foreach_vnode(struct mount *mp,
int (*func)(struct vnode *, void *), void *arg) {
struct vnode *vp, *nvp;
int error = 0;
loop:
TAILQ_FOREACH_SAFE(vp , &mp->mnt_vnodelist, v_mntvnodes, nvp) {
if (vp->v_mount != mp)
goto loop;
error = func(vp, arg);
if (error != 0)
break;
}
return (error);
}
struct vflush_args {
struct vnode *skipvp;
int busy;
int flags;
};
int
vflush_vnode(struct vnode *vp, void *arg)
{
struct vflush_args *va = arg;
struct proc *p = curproc;
if (vp == va->skipvp) {
return (0);
}
if ((va->flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM)) {
return (0);
}
/*
* If WRITECLOSE is set, only flush out regular file
* vnodes open for writing.
*/
if ((va->flags & WRITECLOSE) &&
(vp->v_writecount == 0 || vp->v_type != VREG)) {
return (0);
}
/*
* 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) {
vgonel(vp, p);
return (0);
}
/*
* 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 (va->flags & FORCECLOSE) {
if (vp->v_type != VBLK && vp->v_type != VCHR) {
vgonel(vp, p);
} else {
vclean(vp, 0, p);
vp->v_op = &spec_vops;
insmntque(vp, NULL);
}
return (0);
}
/*
* If set, this is allowed to ignore vnodes which don't
* have changes pending to disk.
* XXX Might be nice to check per-fs "inode" flags, but
* generally the filesystem is sync'd already, right?
*/
if ((va->flags & IGNORECLEAN) &&
LIST_EMPTY(&vp->v_dirtyblkhd))
return (0);
#ifdef DEBUG
if (busyprt)
vprint("vflush: busy vnode", vp);
#endif
va->busy++;
return (0);
}
int
vflush(struct mount *mp, struct vnode *skipvp, int flags)
{
struct vflush_args va;
va.skipvp = skipvp;
va.busy = 0;
va.flags = flags;
vfs_mount_foreach_vnode(mp, vflush_vnode, &va);
if (va.busy)
return (EBUSY);
return (0);
}
/*
* Disassociate the underlying file system from a vnode.
*/
void
vclean(struct vnode *vp, int flags, struct proc *p)
{
int active;
/*
* Check to see if the vnode is in use.
* If so we have to reference it before we clean it out
* so that its count cannot fall to zero and generate a
* race against ourselves to recycle it.
*/
if ((active = vp->v_usecount) != 0)
vp->v_usecount++;
/*
* Prevent the vnode from being recycled or
* brought into use while we clean it out.
*/
if (vp->v_flag & VXLOCK)
panic("vclean: deadlock");
vp->v_flag |= VXLOCK;
/*
* Even if the count is zero, the VOP_INACTIVE routine may still