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freebsd/sys/kern/vfs_export.c
David Greenman 24a1cce34f NOTE: libkvm, w, ps, 'top', and any other utility which depends on struct 
proc or any VM system structure will have to be rebuilt!!!

Much needed overhaul of the VM system. Included in this first round of
changes:

1) Improved pager interfaces: init, alloc, dealloc, getpages, putpages,
   haspage, and sync operations are supported. The haspage interface now
   provides information about clusterability. All pager routines now take
   struct vm_object's instead of "pagers".

2) Improved data structures. In the previous paradigm, there is constant
   confusion caused by pagers being both a data structure ("allocate a
   pager") and a collection of routines. The idea of a pager structure has
   escentially been eliminated. Objects now have types, and this type is
   used to index the appropriate pager. In most cases, items in the pager
   structure were duplicated in the object data structure and thus were
   unnecessary. In the few cases that remained, a un_pager structure union
   was created in the object to contain these items.

3) Because of the cleanup of #1 & #2, a lot of unnecessary layering can now
   be removed. For instance, vm_object_enter(), vm_object_lookup(),
   vm_object_remove(), and the associated object hash list were some of the
   things that were removed.

4) simple_lock's removed. Discussion with several people reveals that the
   SMP locking primitives used in the VM system aren't likely the mechanism
   that we'll be adopting. Even if it were, the locking that was in the code
   was very inadequate and would have to be mostly re-done anyway. The
   locking in a uni-processor kernel was a no-op but went a long way toward
   making the code difficult to read and debug.

5) Places that attempted to kludge-up the fact that we don't have kernel
   thread support have been fixed to reflect the reality that we are really
   dealing with processes, not threads. The VM system didn't have complete
   thread support, so the comments and mis-named routines were just wrong.
   We now use tsleep and wakeup directly in the lock routines, for instance.

6) Where appropriate, the pagers have been improved, especially in the
   pager_alloc routines. Most of the pager_allocs have been rewritten and
   are now faster and easier to maintain.

7) The pagedaemon pageout clustering algorithm has been rewritten and
   now tries harder to output an even number of pages before and after
   the requested page. This is sort of the reverse of the ideal pagein
   algorithm and should provide better overall performance.

8) Unnecessary (incorrect) casts to caddr_t in calls to tsleep & wakeup
   have been removed. Some other unnecessary casts have also been removed.

9) Some almost useless debugging code removed.

10) Terminology of shadow objects vs. backing objects straightened out.
    The fact that the vm_object data structure escentially had this
    backwards really confused things. The use of "shadow" and "backing
    object" throughout the code is now internally consistent and correct
    in the Mach terminology.

11) Several minor bug fixes, including one in the vm daemon that caused
    0 RSS objects to not get purged as intended.

12) A "default pager" has now been created which cleans up the transition
    of objects to the "swap" type. The previous checks throughout the code
    for swp->pg_data != NULL were really ugly. This change also provides
    the rudiments for future backing of "anonymous" memory by something
    other than the swap pager (via the vnode pager, for example), and it
    allows the decision about which of these pagers to use to be made
    dynamically (although will need some additional decision code to do
    this, of course).

13) (dyson) MAP_COPY has been deprecated and the corresponding "copy
    object" code has been removed. MAP_COPY was undocumented and non-
    standard. It was furthermore broken in several ways which caused its
    behavior to degrade to MAP_PRIVATE. Binaries that use MAP_COPY will
    continue to work correctly, but via the slightly different semantics
    of MAP_PRIVATE.

14) (dyson) Sharing maps have been removed. It's marginal usefulness in a
    threads design can be worked around in other ways. Both #12 and #13
    were done to simplify the code and improve readability and maintain-
    ability. (As were most all of these changes)

TODO:

1) Rewrite most of the vnode pager to use VOP_GETPAGES/PUTPAGES. Doing
   this will reduce the vnode pager to a mere fraction of its current size.

2) Rewrite vm_fault and the swap/vnode pagers to use the clustering
   information provided by the new haspage pager interface. This will
   substantially reduce the overhead by eliminating a large number of
   VOP_BMAP() calls. The VOP_BMAP() filesystem interface should be
   improved to provide both a "behind" and "ahead" indication of
   contiguousness.

3) Implement the extended features of pager_haspage in swap_pager_haspage().
   It currently just says 0 pages ahead/behind.

4) Re-implement the swap device (swstrategy) in a more elegant way, perhaps
   via a much more general mechanism that could also be used for disk
   striping of regular filesystems.

5) Do something to improve the architecture of vm_object_collapse(). The
   fact that it makes calls into the swap pager and knows too much about
   how the swap pager operates really bothers me. It also doesn't allow
   for collapsing of non-swap pager objects ("unnamed" objects backed by
   other pagers).
1995-07-13 08:48:48 +00:00

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/*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vfs_subr.c 8.13 (Berkeley) 4/18/94
* $Id: vfs_subr.c,v 1.33 1995/07/08 04:10:32 davidg Exp $
*/
/*
* External virtual filesystem routines
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/file.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/time.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/domain.h>
#include <sys/mbuf.h>
#include <vm/vm.h>
#include <sys/sysctl.h>
#include <miscfs/specfs/specdev.h>
void insmntque __P((struct vnode *, struct mount *));
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,
};
/*
* 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); \
(bp)->b_vnbufs.le_next = NOLIST; \
}
TAILQ_HEAD(freelst, vnode) vnode_free_list; /* vnode free list */
u_long freevnodes = 0;
struct mntlist mountlist; /* mounted filesystem list */
int desiredvnodes;
/*
* Initialize the vnode management data structures.
*/
void
vntblinit()
{
desiredvnodes = maxproc + vm_object_cache_max;
TAILQ_INIT(&vnode_free_list);
TAILQ_INIT(&mountlist);
}
/*
* Lock a filesystem.
* Used to prevent access to it while mounting and unmounting.
*/
int
vfs_lock(mp)
register struct mount *mp;
{
while (mp->mnt_flag & MNT_MLOCK) {
mp->mnt_flag |= MNT_MWAIT;
(void) tsleep((caddr_t) mp, PVFS, "vfslck", 0);
}
mp->mnt_flag |= MNT_MLOCK;
return (0);
}
/*
* Unlock a locked filesystem.
* Panic if filesystem is not locked.
*/
void
vfs_unlock(mp)
register struct mount *mp;
{
if ((mp->mnt_flag & MNT_MLOCK) == 0)
panic("vfs_unlock: not locked");
mp->mnt_flag &= ~MNT_MLOCK;
if (mp->mnt_flag & MNT_MWAIT) {
mp->mnt_flag &= ~MNT_MWAIT;
wakeup((caddr_t) mp);
}
}
/*
* Mark a mount point as busy.
* Used to synchronize access and to delay unmounting.
*/
int
vfs_busy(mp)
register struct mount *mp;
{
while (mp->mnt_flag & MNT_MPBUSY) {
mp->mnt_flag |= MNT_MPWANT;
(void) tsleep((caddr_t) &mp->mnt_flag, PVFS, "vfsbsy", 0);
}
if (mp->mnt_flag & MNT_UNMOUNT)
return (1);
mp->mnt_flag |= MNT_MPBUSY;
return (0);
}
/*
* Free a busy filesystem.
* Panic if filesystem is not busy.
*/
void
vfs_unbusy(mp)
register struct mount *mp;
{
if ((mp->mnt_flag & MNT_MPBUSY) == 0)
panic("vfs_unbusy: not busy");
mp->mnt_flag &= ~MNT_MPBUSY;
if (mp->mnt_flag & MNT_MPWANT) {
mp->mnt_flag &= ~MNT_MPWANT;
wakeup((caddr_t) &mp->mnt_flag);
}
}
void
vfs_unmountroot(rootfs)
struct mount *rootfs;
{
struct mount *mp = rootfs;
int error;
if (vfs_busy(mp)) {
printf("failed to unmount root\n");
return;
}
mp->mnt_flag |= MNT_UNMOUNT;
if ((error = vfs_lock(mp))) {
printf("lock of root filesystem failed (%d)\n", error);
return;
}
vnode_pager_umount(mp); /* release cached vnodes */
cache_purgevfs(mp); /* remove cache entries for this file sys */
if ((error = VFS_SYNC(mp, MNT_WAIT, initproc->p_ucred, initproc)))
printf("sync of root filesystem failed (%d)\n", error);
if ((error = VFS_UNMOUNT(mp, MNT_FORCE, initproc))) {
printf("unmount of root filesystem failed (");
if (error == EBUSY)
printf("BUSY)\n");
else
printf("%d)\n", error);
}
mp->mnt_flag &= ~MNT_UNMOUNT;
vfs_unbusy(mp);
}
/*
* Unmount all filesystems. Should only be called by halt().
*/
void
vfs_unmountall()
{
struct mount *mp, *mp_next, *rootfs = NULL;
int error;
/* unmount all but rootfs */
for (mp = mountlist.tqh_first; mp != NULL; mp = mp_next) {
mp_next = mp->mnt_list.tqe_next;
if (mp->mnt_flag & MNT_ROOTFS) {
rootfs = mp;
continue;
}
error = dounmount(mp, MNT_FORCE, initproc);
if (error) {
printf("unmount of %s failed (", mp->mnt_stat.f_mntonname);
if (error == EBUSY)
printf("BUSY)\n");
else
printf("%d)\n", error);
}
}
/* and finally... */
if (rootfs) {
vfs_unmountroot(rootfs);
} else {
printf("no root filesystem\n");
}
}
/*
* Lookup a mount point by filesystem identifier.
*/
struct mount *
getvfs(fsid)
fsid_t *fsid;
{
register struct mount *mp;
for (mp = mountlist.tqh_first; mp != NULL; mp = mp->mnt_list.tqe_next) {
if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
mp->mnt_stat.f_fsid.val[1] == fsid->val[1])
return (mp);
}
return ((struct mount *) 0);
}
/*
* Get a new unique fsid
*/
void
getnewfsid(mp, mtype)
struct mount *mp;
int mtype;
{
static u_short xxxfs_mntid;
fsid_t tfsid;
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 (mountlist.tqh_first != NULL) {
while (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(vap)
register struct vattr *vap;
{
vap->va_type = VNON;
vap->va_size = VNOVAL;
vap->va_bytes = VNOVAL;
vap->va_mode = vap->va_nlink = vap->va_uid = vap->va_gid =
vap->va_fsid = vap->va_fileid =
vap->va_blocksize = vap->va_rdev =
vap->va_atime.ts_sec = vap->va_atime.ts_nsec =
vap->va_mtime.ts_sec = vap->va_mtime.ts_nsec =
vap->va_ctime.ts_sec = vap->va_ctime.ts_nsec =
vap->va_flags = vap->va_gen = VNOVAL;
vap->va_vaflags = 0;
}
/*
* Routines having to do with the management of the vnode table.
*/
extern int (**dead_vnodeop_p) ();
extern void vclean();
/*
* Return the next vnode from the free list.
*/
int
getnewvnode(tag, mp, vops, vpp)
enum vtagtype tag;
struct mount *mp;
int (**vops) ();
struct vnode **vpp;
{
register struct vnode *vp;
vp = vnode_free_list.tqh_first;
/*
* we allocate a new vnode if
* 1. we don't have any free
* Pretty obvious, we actually used to panic, but that
* is a silly thing to do.
* 2. we havn't filled our pool yet
* We don't want to trash the incore (VM-)vnodecache.
* 3. if less that 1/4th of our vnodes are free.
* We don't want to trash the namei cache either.
*/
if (freevnodes < (numvnodes >> 2) ||
numvnodes < desiredvnodes ||
vp == NULL) {
vp = (struct vnode *) malloc((u_long) sizeof *vp,
M_VNODE, M_WAITOK);
bzero((char *) vp, sizeof *vp);
numvnodes++;
} else {
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
freevnodes--;
if (vp->v_usecount)
panic("free vnode isn't");
/* see comment on why 0xdeadb is set at end of vgone (below) */
vp->v_freelist.tqe_prev = (struct vnode **) 0xdeadb;
vp->v_lease = NULL;
if (vp->v_type != VBAD)
vgone(vp);
#ifdef DIAGNOSTIC
{
int s;
if (vp->v_data)
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_lastr = 0;
vp->v_ralen = 0;
vp->v_maxra = 0;
vp->v_lastw = 0;
vp->v_lasta = 0;
vp->v_cstart = 0;
vp->v_clen = 0;
vp->v_socket = 0;
vp->v_writecount = 0; /* XXX */
}
vp->v_type = VNON;
cache_purge(vp);
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(vp, mp)
register struct vnode *vp;
register struct mount *mp;
{
/*
* Delete from old mount point vnode list, if on one.
*/
if (vp->v_mount != NULL)
LIST_REMOVE(vp, v_mntvnodes);
/*
* Insert into list of vnodes for the new mount point, if available.
*/
if ((vp->v_mount = mp) == NULL)
return;
LIST_INSERT_HEAD(&mp->mnt_vnodelist, vp, v_mntvnodes);
}
/*
* Update outstanding I/O count and do wakeup if requested.
*/
void
vwakeup(bp)
register struct buf *bp;
{
register struct vnode *vp;
bp->b_flags &= ~B_WRITEINPROG;
if ((vp = bp->b_vp)) {
vp->v_numoutput--;
if (vp->v_numoutput < 0)
panic("vwakeup: neg numoutput");
if ((vp->v_numoutput == 0) && (vp->v_flag & VBWAIT)) {
vp->v_flag &= ~VBWAIT;
wakeup((caddr_t) &vp->v_numoutput);
}
}
}
/*
* Flush out and invalidate all buffers associated with a vnode.
* Called with the underlying object locked.
*/
int
vinvalbuf(vp, flags, cred, p, slpflag, slptimeo)
register struct vnode *vp;
int flags;
struct ucred *cred;
struct proc *p;
int slpflag, slptimeo;
{
register struct buf *bp;
struct buf *nbp, *blist;
int s, error;
vm_object_t object;
if (flags & V_SAVE) {
if ((error = VOP_FSYNC(vp, cred, MNT_WAIT, p)))
return (error);
if (vp->v_dirtyblkhd.lh_first != NULL)
panic("vinvalbuf: dirty bufs");
}
for (;;) {
if ((blist = vp->v_cleanblkhd.lh_first) && (flags & V_SAVEMETA))
while (blist && blist->b_lblkno < 0)
blist = blist->b_vnbufs.le_next;
if (!blist && (blist = vp->v_dirtyblkhd.lh_first) &&
(flags & V_SAVEMETA))
while (blist && blist->b_lblkno < 0)
blist = blist->b_vnbufs.le_next;
if (!blist)
break;
for (bp = blist; bp; bp = nbp) {
nbp = bp->b_vnbufs.le_next;
if ((flags & V_SAVEMETA) && bp->b_lblkno < 0)
continue;
s = splbio();
if (bp->b_flags & B_BUSY) {
bp->b_flags |= B_WANTED;
error = tsleep((caddr_t) bp,
slpflag | (PRIBIO + 1), "vinvalbuf",
slptimeo);
splx(s);
if (error)
return (error);
break;
}
bremfree(bp);
bp->b_flags |= B_BUSY;
splx(s);
/*
* XXX Since there are no node locks for NFS, I
* believe there is a slight chance that a delayed
* write will occur while sleeping just above, so
* check for it.
*/
if ((bp->b_flags & B_DELWRI) && (flags & V_SAVE)) {
(void) VOP_BWRITE(bp);
break;
}
bp->b_flags |= (B_INVAL|B_NOCACHE|B_RELBUF);
brelse(bp);
}
}
s = splbio();
while (vp->v_numoutput > 0) {
vp->v_flag |= VBWAIT;
tsleep(&vp->v_numoutput, PVM, "vnvlbv", 0);
}
splx(s);
/*
* Destroy the copy in the VM cache, too.
*/
object = vp->v_object;
if (object != NULL) {
vm_object_page_remove(object, 0, object->size,
(flags & V_SAVE) ? TRUE : FALSE);
}
if (!(flags & V_SAVEMETA) &&
(vp->v_dirtyblkhd.lh_first || vp->v_cleanblkhd.lh_first))
panic("vinvalbuf: flush failed");
return (0);
}
/*
* Associate a buffer with a vnode.
*/
void
bgetvp(vp, bp)
register struct vnode *vp;
register struct buf *bp;
{
int s;
if (bp->b_vp)
panic("bgetvp: not free");
VHOLD(vp);
bp->b_vp = vp;
if (vp->v_type == VBLK || vp->v_type == VCHR)
bp->b_dev = vp->v_rdev;
else
bp->b_dev = NODEV;
/*
* Insert onto list for new vnode.
*/
s = splbio();
bufinsvn(bp, &vp->v_cleanblkhd);
splx(s);
}
/*
* Disassociate a buffer from a vnode.
*/
void
brelvp(bp)
register struct buf *bp;
{
struct vnode *vp;
int s;
if (bp->b_vp == (struct vnode *) 0)
panic("brelvp: NULL");
/*
* Delete from old vnode list, if on one.
*/
s = splbio();
if (bp->b_vnbufs.le_next != NOLIST)
bufremvn(bp);
splx(s);
vp = bp->b_vp;
bp->b_vp = (struct vnode *) 0;
HOLDRELE(vp);
}
/*
* Associate a p-buffer with a vnode.
*/
void
pbgetvp(vp, bp)
register struct vnode *vp;
register struct buf *bp;
{
if (bp->b_vp)
panic("pbgetvp: not free");
VHOLD(vp);
bp->b_vp = vp;
if (vp->v_type == VBLK || vp->v_type == VCHR)
bp->b_dev = vp->v_rdev;
else
bp->b_dev = NODEV;
}
/*
* Disassociate a p-buffer from a vnode.
*/
void
pbrelvp(bp)
register struct buf *bp;
{
struct vnode *vp;
if (bp->b_vp == (struct vnode *) 0)
panic("brelvp: NULL");
vp = bp->b_vp;
bp->b_vp = (struct vnode *) 0;
HOLDRELE(vp);
}
/*
* Reassign a buffer from one vnode to another.
* Used to assign file specific control information
* (indirect blocks) to the vnode to which they belong.
*/
void
reassignbuf(bp, newvp)
register struct buf *bp;
register struct vnode *newvp;
{
register struct buflists *listheadp;
if (newvp == NULL) {
printf("reassignbuf: NULL");
return;
}
/*
* Delete from old vnode list, if on one.
*/
if (bp->b_vnbufs.le_next != NOLIST)
bufremvn(bp);
/*
* If dirty, put on list of dirty buffers; otherwise insert onto list
* of clean buffers.
*/
if (bp->b_flags & B_DELWRI) {
struct buf *tbp;
tbp = newvp->v_dirtyblkhd.lh_first;
if (!tbp || (tbp->b_lblkno > bp->b_lblkno)) {
bufinsvn(bp, &newvp->v_dirtyblkhd);
} else {
while (tbp->b_vnbufs.le_next && (tbp->b_vnbufs.le_next->b_lblkno < bp->b_lblkno)) {
tbp = tbp->b_vnbufs.le_next;
}
LIST_INSERT_AFTER(tbp, bp, b_vnbufs);
}
} else {
listheadp = &newvp->v_cleanblkhd;
bufinsvn(bp, listheadp);
}
}
/*
* 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, vpp)
dev_t dev;
struct vnode **vpp;
{
register struct vnode *vp;
struct vnode *nvp;
int error;
if (dev == NODEV)
return (0);
error = getnewvnode(VT_NON, (struct mount *) 0, spec_vnodeop_p, &nvp);
if (error) {
*vpp = 0;
return (error);
}
vp = nvp;
vp->v_type = VBLK;
if ((nvp = checkalias(vp, dev, (struct mount *) 0))) {
vput(vp);
vp = nvp;
}
*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(nvp, nvp_rdev, mp)
register struct vnode *nvp;
dev_t nvp_rdev;
struct mount *mp;
{
register struct vnode *vp;
struct vnode **vpp;
if (nvp->v_type != VBLK && nvp->v_type != VCHR)
return (NULLVP);
vpp = &speclisth[SPECHASH(nvp_rdev)];
loop:
for (vp = *vpp; vp; vp = vp->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) {
vgone(vp);
goto loop;
}
if (vget(vp, 1))
goto loop;
break;
}
if (vp == NULL || vp->v_tag != VT_NON) {
MALLOC(nvp->v_specinfo, struct specinfo *,
sizeof(struct specinfo), M_VNODE, M_WAITOK);
nvp->v_rdev = nvp_rdev;
nvp->v_hashchain = vpp;
nvp->v_specnext = *vpp;
nvp->v_specflags = 0;
*vpp = nvp;
if (vp != NULL) {
nvp->v_flag |= VALIASED;
vp->v_flag |= VALIASED;
vput(vp);
}
return (NULLVP);
}
VOP_UNLOCK(vp);
vclean(vp, 0);
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. The vnode lock bit is set the
* vnode is being eliminated in vgone. 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(vp, lockflag)
register struct vnode *vp;
int lockflag;
{
/*
* 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 either by checking that the VXLOCK flag is
* set, or that the use count is zero with the back pointer set to
* show that it has been removed from the free list by getnewvnode.
* The VXLOCK flag may not have been set yet because vclean is blocked
* in the VOP_LOCK call waiting for the VOP_INACTIVE to complete.
*/
if ((vp->v_flag & VXLOCK) ||
(vp->v_usecount == 0 &&
vp->v_freelist.tqe_prev == (struct vnode **) 0xdeadb)) {
vp->v_flag |= VXWANT;
(void) tsleep((caddr_t) vp, PINOD, "vget", 0);
return (1);
}
if (vp->v_usecount == 0) {
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
freevnodes--;
}
vp->v_usecount++;
if (lockflag)
VOP_LOCK(vp);
return (0);
}
/*
* Vnode reference, just increment the count
*/
void
vref(vp)
struct vnode *vp;
{
if (vp->v_usecount <= 0)
panic("vref used where vget required");
vp->v_usecount++;
}
/*
* vput(), just unlock and vrele()
*/
void
vput(vp)
register struct vnode *vp;
{
VOP_UNLOCK(vp);
vrele(vp);
}
/*
* Vnode release.
* If count drops to zero, call inactive routine and return to freelist.
*/
void
vrele(vp)
register struct vnode *vp;
{
#ifdef DIAGNOSTIC
if (vp == NULL)
panic("vrele: null vp");
#endif
vp->v_usecount--;
if (vp->v_usecount > 0)
return;
#ifdef DIAGNOSTIC
if (vp->v_usecount < 0 /* || vp->v_writecount < 0 */ ) {
vprint("vrele: negative ref count", vp);
panic("vrele: negative reference cnt");
}
#endif
if (vp->v_flag & VAGE) {
TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
vp->v_flag &= ~VAGE;
} else {
TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
}
freevnodes++;
VOP_INACTIVE(vp);
}
/*
* Page or buffer structure gets a reference.
*/
void
vhold(vp)
register struct vnode *vp;
{
vp->v_holdcnt++;
}
/*
* Page or buffer structure frees a reference.
*/
void
holdrele(vp)
register struct vnode *vp;
{
if (vp->v_holdcnt <= 0)
panic("holdrele: holdcnt");
vp->v_holdcnt--;
}
/*
* 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 DIAGNOSTIC
int busyprt = 0; /* print out busy vnodes */
struct ctldebug debug1 = {"busyprt", &busyprt};
#endif
int
vflush(mp, skipvp, flags)
struct mount *mp;
struct vnode *skipvp;
int flags;
{
register struct vnode *vp, *nvp;
int busy = 0;
if ((mp->mnt_flag & MNT_MPBUSY) == 0)
panic("vflush: not busy");
loop:
for (vp = mp->mnt_vnodelist.lh_first; vp; vp = nvp) {
/*
* Make sure this vnode wasn't reclaimed in getnewvnode().
* Start over if it has (it won't be on the list anymore).
*/
if (vp->v_mount != mp)
goto loop;
nvp = vp->v_mntvnodes.le_next;
/*
* Skip over a selected vnode.
*/
if (vp == skipvp)
continue;
/*
* Skip over a vnodes marked VSYSTEM.
*/
if ((flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM))
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))
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) {
vgone(vp);
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) {
if (vp->v_type != VBLK && vp->v_type != VCHR) {
vgone(vp);
} else {
vclean(vp, 0);
vp->v_op = spec_vnodeop_p;
insmntque(vp, (struct mount *) 0);
}
continue;
}
#ifdef DIAGNOSTIC
if (busyprt)
vprint("vflush: busy vnode", vp);
#endif
busy++;
}
if (busy)
return (EBUSY);
return (0);
}
/*
* Disassociate the underlying file system from a vnode.
*/
void
vclean(vp, flags)
register struct vnode *vp;
int flags;
{
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))
VREF(vp);
/*
* Even if the count is zero, the VOP_INACTIVE routine may still have
* the object locked while it cleans it out. The VOP_LOCK ensures that
* the VOP_INACTIVE routine is done with its work. For active vnodes,
* it ensures that no other activity can occur while the underlying
* object is being cleaned out.
*/
VOP_LOCK(vp);
/*
* 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;
/*
* Clean out any buffers associated with the vnode.
*/
if (flags & DOCLOSE)
vinvalbuf(vp, V_SAVE, NOCRED, NULL, 0, 0);
/*
* Any other processes trying to obtain this lock must first wait for
* VXLOCK to clear, then call the new lock operation.
*/
VOP_UNLOCK(vp);
/*
* If purging an active vnode, it must be closed and deactivated
* before being reclaimed.
*/
if (active) {
if (flags & DOCLOSE)
VOP_CLOSE(vp, FNONBLOCK, NOCRED, NULL);
VOP_INACTIVE(vp);
}
/*
* Reclaim the vnode.
*/
if (VOP_RECLAIM(vp))
panic("vclean: cannot reclaim");
if (active)
vrele(vp);
/*
* Done with purge, notify sleepers of the grim news.
*/
vp->v_op = dead_vnodeop_p;
vp->v_tag = VT_NON;
vp->v_flag &= ~VXLOCK;
if (vp->v_flag & VXWANT) {
vp->v_flag &= ~VXWANT;
wakeup((caddr_t) vp);
}
}
/*
* Eliminate all activity associated with the requested vnode
* and with all vnodes aliased to the requested vnode.
*/
void
vgoneall(vp)
register struct vnode *vp;
{
register struct vnode *vq;
if (vp->v_flag & VALIASED) {
/*
* If a vgone (or vclean) is already in progress, wait until
* it is done and return.
*/
if (vp->v_flag & VXLOCK) {
vp->v_flag |= VXWANT;
(void) tsleep((caddr_t) vp, PINOD, "vgall", 0);
return;
}
/*
* Ensure that vp will not be vgone'd while we are eliminating
* its aliases.
*/
vp->v_flag |= VXLOCK;
while (vp->v_flag & VALIASED) {
for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
if (vq->v_rdev != vp->v_rdev ||
vq->v_type != vp->v_type || vp == vq)
continue;
vgone(vq);
break;
}
}
/*
* Remove the lock so that vgone below will really eliminate
* the vnode after which time vgone will awaken any sleepers.
*/
vp->v_flag &= ~VXLOCK;
}
vgone(vp);
}
/*
* Eliminate all activity associated with a vnode
* in preparation for reuse.
*/
void
vgone(vp)
register struct vnode *vp;
{
register struct vnode *vq;
struct vnode *vx;
/*
* If a vgone (or vclean) is already in progress, wait until it is
* done and return.
*/
if (vp->v_flag & VXLOCK) {
vp->v_flag |= VXWANT;
(void) tsleep((caddr_t) vp, PINOD, "vgone", 0);
return;
}
/*
* Clean out the filesystem specific data.
*/
vclean(vp, DOCLOSE);
/*
* Delete from old mount point vnode list, if on one.
*/
if (vp->v_mount != NULL) {
LIST_REMOVE(vp, v_mntvnodes);
vp->v_mount = NULL;
}
/*
* If special device, remove it from special device alias list.
*/
if (vp->v_type == VBLK || vp->v_type == VCHR) {
if (*vp->v_hashchain == vp) {
*vp->v_hashchain = vp->v_specnext;
} else {
for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
if (vq->v_specnext != vp)
continue;
vq->v_specnext = vp->v_specnext;
break;
}
if (vq == NULL)
panic("missing bdev");
}
if (vp->v_flag & VALIASED) {
vx = NULL;
for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
if (vq->v_rdev != vp->v_rdev ||
vq->v_type != vp->v_type)
continue;
if (vx)
break;
vx = vq;
}
if (vx == NULL)
panic("missing alias");
if (vq == NULL)
vx->v_flag &= ~VALIASED;
vp->v_flag &= ~VALIASED;
}
FREE(vp->v_specinfo, M_VNODE);
vp->v_specinfo = NULL;
}
/*
* If it is on the freelist and not already at the head, move it to
* the head of the list. The test of the back pointer and the
* reference count of zero is because it will be removed from the free
* list by getnewvnode, but will not have its reference count
* incremented until after calling vgone. If the reference count were
* incremented first, vgone would (incorrectly) try to close the
* previous instance of the underlying object. So, the back pointer is
* explicitly set to `0xdeadb' in getnewvnode after removing it from
* the freelist to ensure that we do not try to move it here.
*/
if (vp->v_usecount == 0 &&
vp->v_freelist.tqe_prev != (struct vnode **) 0xdeadb &&
vnode_free_list.tqh_first != vp) {
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
}
vp->v_type = VBAD;
}
/*
* Lookup a vnode by device number.
*/
int
vfinddev(dev, type, vpp)
dev_t dev;
enum vtype type;
struct vnode **vpp;
{
register struct vnode *vp;
for (vp = speclisth[SPECHASH(dev)]; vp; vp = vp->v_specnext) {
if (dev != vp->v_rdev || type != vp->v_type)
continue;
*vpp = vp;
return (1);
}
return (0);
}
/*
* Calculate the total number of references to a special device.
*/
int
vcount(vp)
register struct vnode *vp;
{
register struct vnode *vq, *vnext;
int count;
loop:
if ((vp->v_flag & VALIASED) == 0)
return (vp->v_usecount);
for (count = 0, vq = *vp->v_hashchain; vq; vq = vnext) {
vnext = vq->v_specnext;
if (vq->v_rdev != vp->v_rdev || vq->v_type != vp->v_type)
continue;
/*
* Alias, but not in use, so flush it out.
*/
if (vq->v_usecount == 0 && vq != vp) {
vgone(vq);
goto loop;
}
count += vq->v_usecount;
}
return (count);
}
/*
* Print out a description of a vnode.
*/
static char *typename[] =
{"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
void
vprint(label, vp)
char *label;
register struct vnode *vp;
{
char buf[64];
if (label != NULL)
printf("%s: ", label);
printf("type %s, usecount %d, writecount %d, refcount %ld,",
typename[vp->v_type], vp->v_usecount, vp->v_writecount,
vp->v_holdcnt);
buf[0] = '\0';
if (vp->v_flag & VROOT)
strcat(buf, "|VROOT");
if (vp->v_flag & VTEXT)
strcat(buf, "|VTEXT");
if (vp->v_flag & VSYSTEM)
strcat(buf, "|VSYSTEM");
if (vp->v_flag & VXLOCK)
strcat(buf, "|VXLOCK");
if (vp->v_flag & VXWANT)
strcat(buf, "|VXWANT");
if (vp->v_flag & VBWAIT)
strcat(buf, "|VBWAIT");
if (vp->v_flag & VALIASED)
strcat(buf, "|VALIASED");
if (buf[0] != '\0')
printf(" flags (%s)", &buf[1]);
if (vp->v_data == NULL) {
printf("\n");
} else {
printf("\n\t");
VOP_PRINT(vp);
}
}
#ifdef DDB
/*
* List all of the locked vnodes in the system.
* Called when debugging the kernel.
*/
void
printlockedvnodes()
{
register struct mount *mp;
register struct vnode *vp;
printf("Locked vnodes\n");
for (mp = mountlist.tqh_first; mp != NULL; mp = mp->mnt_list.tqe_next) {
for (vp = mp->mnt_vnodelist.lh_first;
vp != NULL;
vp = vp->v_mntvnodes.le_next)
if (VOP_ISLOCKED(vp))
vprint((char *) 0, vp);
}
}
#endif
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_vnode(where, sizep)
char *where;
size_t *sizep;
{
register struct mount *mp, *nmp;
struct vnode *vp;
register char *bp = where, *savebp;
char *ewhere;
int error;
#define VPTRSZ sizeof (struct vnode *)
#define VNODESZ sizeof (struct vnode)
if (where == NULL) {
*sizep = (numvnodes + KINFO_VNODESLOP) * (VPTRSZ + VNODESZ);
return (0);
}
ewhere = where + *sizep;
for (mp = mountlist.tqh_first; mp != NULL; mp = nmp) {
nmp = mp->mnt_list.tqe_next;
if (vfs_busy(mp))
continue;
savebp = bp;
again:
for (vp = mp->mnt_vnodelist.lh_first;
vp != NULL;
vp = vp->v_mntvnodes.le_next) {
/*
* Check that the vp is still associated with this
* filesystem. RACE: could have been recycled onto
* the same filesystem.
*/
if (vp->v_mount != mp) {
if (kinfo_vdebug)
printf("kinfo: vp changed\n");
bp = savebp;
goto again;
}
if (bp + VPTRSZ + VNODESZ > ewhere) {
*sizep = bp - where;
return (ENOMEM);
}
if ((error = copyout((caddr_t) &vp, bp, VPTRSZ)) ||
(error = copyout((caddr_t) vp, bp + VPTRSZ, VNODESZ)))
return (error);
bp += VPTRSZ + VNODESZ;
}
vfs_unbusy(mp);
}
*sizep = bp - where;
return (0);
}
/*
* Check to see if a filesystem is mounted on a block device.
*/
int
vfs_mountedon(vp)
register struct vnode *vp;
{
register struct vnode *vq;
if (vp->v_specflags & SI_MOUNTEDON)
return (EBUSY);
if (vp->v_flag & VALIASED) {
for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
if (vq->v_rdev != vp->v_rdev ||
vq->v_type != vp->v_type)
continue;
if (vq->v_specflags & SI_MOUNTEDON)
return (EBUSY);
}
}
return (0);
}
/*
* Build hash lists of net addresses and hang them off the mount point.
* Called by ufs_mount() to set up the lists of export addresses.
*/
static int
vfs_hang_addrlist(mp, nep, argp)
struct mount *mp;
struct netexport *nep;
struct export_args *argp;
{
register struct netcred *np;
register struct radix_node_head *rnh;
register int i;
struct radix_node *rn;
struct sockaddr *saddr, *smask = 0;
struct domain *dom;
int error;
if (argp->ex_addrlen == 0) {
if (mp->mnt_flag & MNT_DEFEXPORTED)
return (EPERM);
np = &nep->ne_defexported;
np->netc_exflags = argp->ex_flags;
np->netc_anon = argp->ex_anon;
np->netc_anon.cr_ref = 1;
mp->mnt_flag |= MNT_DEFEXPORTED;
return (0);
}
i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
np = (struct netcred *) malloc(i, M_NETADDR, M_WAITOK);
bzero((caddr_t) np, i);
saddr = (struct sockaddr *) (np + 1);
if ((error = copyin(argp->ex_addr, (caddr_t) saddr, argp->ex_addrlen)))
goto out;
if (saddr->sa_len > argp->ex_addrlen)
saddr->sa_len = argp->ex_addrlen;
if (argp->ex_masklen) {
smask = (struct sockaddr *) ((caddr_t) saddr + argp->ex_addrlen);
error = copyin(argp->ex_addr, (caddr_t) smask, argp->ex_masklen);
if (error)
goto out;
if (smask->sa_len > argp->ex_masklen)
smask->sa_len = argp->ex_masklen;
}
i = saddr->sa_family;
if ((rnh = nep->ne_rtable[i]) == 0) {
/*
* Seems silly to initialize every AF when most are not used,
* do so on demand here
*/
for (dom = domains; dom; dom = dom->dom_next)
if (dom->dom_family == i && dom->dom_rtattach) {
dom->dom_rtattach((void **) &nep->ne_rtable[i],
dom->dom_rtoffset);
break;
}
if ((rnh = nep->ne_rtable[i]) == 0) {
error = ENOBUFS;
goto out;
}
}
rn = (*rnh->rnh_addaddr) ((caddr_t) saddr, (caddr_t) smask, rnh,
np->netc_rnodes);
if (rn == 0 || np != (struct netcred *) rn) { /* already exists */
error = EPERM;
goto out;
}
np->netc_exflags = argp->ex_flags;
np->netc_anon = argp->ex_anon;
np->netc_anon.cr_ref = 1;
return (0);
out:
free(np, M_NETADDR);
return (error);
}
/* ARGSUSED */
static int
vfs_free_netcred(rn, w)
struct radix_node *rn;
caddr_t w;
{
register struct radix_node_head *rnh = (struct radix_node_head *) w;
(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
free((caddr_t) rn, M_NETADDR);
return (0);
}
/*
* Free the net address hash lists that are hanging off the mount points.
*/
static void
vfs_free_addrlist(nep)
struct netexport *nep;
{
register int i;
register struct radix_node_head *rnh;
for (i = 0; i <= AF_MAX; i++)
if ((rnh = nep->ne_rtable[i])) {
(*rnh->rnh_walktree) (rnh, vfs_free_netcred,
(caddr_t) rnh);
free((caddr_t) rnh, M_RTABLE);
nep->ne_rtable[i] = 0;
}
}
int
vfs_export(mp, nep, argp)
struct mount *mp;
struct netexport *nep;
struct export_args *argp;
{
int error;
if (argp->ex_flags & MNT_DELEXPORT) {
vfs_free_addrlist(nep);
mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
}
if (argp->ex_flags & MNT_EXPORTED) {
if ((error = vfs_hang_addrlist(mp, nep, argp)))
return (error);
mp->mnt_flag |= MNT_EXPORTED;
}
return (0);
}
struct netcred *
vfs_export_lookup(mp, nep, nam)
register struct mount *mp;
struct netexport *nep;
struct mbuf *nam;
{
register struct netcred *np;
register struct radix_node_head *rnh;
struct sockaddr *saddr;
np = NULL;
if (mp->mnt_flag & MNT_EXPORTED) {
/*
* Lookup in the export list first.
*/
if (nam != NULL) {
saddr = mtod(nam, struct sockaddr *);
rnh = nep->ne_rtable[saddr->sa_family];
if (rnh != NULL) {
np = (struct netcred *)
(*rnh->rnh_matchaddr) ((caddr_t) saddr,
rnh);
if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
np = NULL;
}
}
/*
* If no address match, use the default if it exists.
*/
if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
np = &nep->ne_defexported;
}
return (np);
}
/*
* perform msync on all vnodes under a mount point
* the mount point must be locked.
*/
void
vfs_msync(struct mount *mp, int flags) {
struct vnode *vp;
loop:
for (vp = mp->mnt_vnodelist.lh_first;
vp != NULL;
vp = vp->v_mntvnodes.le_next) {
if (vp->v_mount != mp)
goto loop;
if (VOP_ISLOCKED(vp) && (flags != MNT_WAIT))
continue;
if (vp->v_object &&
(((vm_object_t) vp->v_object)->flags & OBJ_WRITEABLE)) {
vm_object_page_clean(vp->v_object, 0, 0, TRUE, TRUE);
}
}
}
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