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freebsd-dev/sys/kern/vfs_subr.c
Poul-Henning Kamp ff7c5a4880 Alas, poor SPECFS! -- I knew him, Horatio; A filesystem of infinite 
jest, of most excellent fancy: he hath taught me lessons a thousand
times; and now, how abhorred in my imagination it is! my gorge rises
at it.  Here were those hacks that I have curs'd I know not how
oft.  Where be your kludges now? your workarounds? your layering
violations, that were wont to set the table on a roar?

Move the skeleton of specfs into devfs where it now belongs and
bury the rest.
2004-10-22 09:59:37 +00:00

3993 lines
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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.
* 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 8.31 (Berkeley) 5/26/95
*/
/*
* External virtual filesystem routines
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/event.h>
#include <sys/eventhandler.h>
#include <sys/extattr.h>
#include <sys/fcntl.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/mac.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/reboot.h>
#include <sys/sleepqueue.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/vmmeter.h>
#include <sys/vnode.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_extern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_kern.h>
#include <vm/uma.h>
static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
static void addalias(struct vnode *vp, struct cdev *nvp_rdev);
static void delmntque(struct vnode *vp);
static void insmntque(struct vnode *vp, struct mount *mp);
static void vclean(struct vnode *vp, int flags, struct thread *td);
static void vlruvp(struct vnode *vp);
static int flushbuflist(struct buf *blist, int flags, struct vnode *vp,
int slpflag, int slptimeo, int *errorp);
static void syncer_shutdown(void *arg, int howto);
static int vtryrecycle(struct vnode *vp);
static void vx_lock(struct vnode *vp);
static void vx_unlock(struct vnode *vp);
static void vgonechrl(struct vnode *vp, struct thread *td);
/*
* Number of vnodes in existence. Increased whenever getnewvnode()
* allocates a new vnode, never decreased.
*/
static unsigned long numvnodes;
SYSCTL_LONG(_vfs, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0, "");
/*
* Conversion tables for conversion from vnode types to inode formats
* and back.
*/
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,
};
/*
* List of vnodes that are ready for recycling.
*/
static TAILQ_HEAD(freelst, vnode) vnode_free_list;
/*
* Minimum number of free vnodes. If there are fewer than this free vnodes,
* getnewvnode() will return a newly allocated vnode.
*/
static u_long wantfreevnodes = 25;
SYSCTL_LONG(_vfs, OID_AUTO, wantfreevnodes, CTLFLAG_RW, &wantfreevnodes, 0, "");
/* Number of vnodes in the free list. */
static u_long freevnodes;
SYSCTL_LONG(_vfs, OID_AUTO, freevnodes, CTLFLAG_RD, &freevnodes, 0, "");
/*
* Various variables used for debugging the new implementation of
* reassignbuf().
* XXX these are probably of (very) limited utility now.
*/
static int reassignbufcalls;
SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls, 0, "");
static int nameileafonly;
SYSCTL_INT(_vfs, OID_AUTO, nameileafonly, CTLFLAG_RW, &nameileafonly, 0, "");
/*
* Cache for the mount type id assigned to NFS. This is used for
* special checks in nfs/nfs_nqlease.c and vm/vnode_pager.c.
*/
int nfs_mount_type = -1;
/* To keep more than one thread at a time from running vfs_getnewfsid */
static struct mtx mntid_mtx;
/*
* Lock for any access to the following:
* vnode_free_list
* numvnodes
* freevnodes
*/
static struct mtx vnode_free_list_mtx;
/* Publicly exported FS */
struct nfs_public nfs_pub;
/* Zone for allocation of new vnodes - used exclusively by getnewvnode() */
static uma_zone_t vnode_zone;
static uma_zone_t vnodepoll_zone;
/* Set to 1 to print out reclaim of active vnodes */
int prtactive;
/*
* The workitem queue.
*
* It is useful to delay writes of file data and filesystem metadata
* for tens of seconds so that quickly created and deleted files need
* not waste disk bandwidth being created and removed. To realize this,
* we append vnodes to a "workitem" queue. When running with a soft
* updates implementation, most pending metadata dependencies should
* not wait for more than a few seconds. Thus, mounted on block devices
* are delayed only about a half the time that file data is delayed.
* Similarly, directory updates are more critical, so are only delayed
* about a third the time that file data is delayed. Thus, there are
* SYNCER_MAXDELAY queues that are processed round-robin at a rate of
* one each second (driven off the filesystem syncer process). The
* syncer_delayno variable indicates the next queue that is to be processed.
* Items that need to be processed soon are placed in this queue:
*
* syncer_workitem_pending[syncer_delayno]
*
* A delay of fifteen seconds is done by placing the request fifteen
* entries later in the queue:
*
* syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
*
*/
static int syncer_delayno;
static long syncer_mask;
LIST_HEAD(synclist, vnode);
static struct synclist *syncer_workitem_pending;
/*
* The sync_mtx protects:
* vp->v_synclist
* sync_vnode_count
* syncer_delayno
* syncer_state
* syncer_workitem_pending
* syncer_worklist_len
* rushjob
*/
static struct mtx sync_mtx;
#define SYNCER_MAXDELAY 32
static int syncer_maxdelay = SYNCER_MAXDELAY; /* maximum delay time */
static int syncdelay = 30; /* max time to delay syncing data */
static int filedelay = 30; /* time to delay syncing files */
SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0, "");
static int dirdelay = 29; /* time to delay syncing directories */
SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0, "");
static int metadelay = 28; /* time to delay syncing metadata */
SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0, "");
static int rushjob; /* number of slots to run ASAP */
static int stat_rush_requests; /* number of times I/O speeded up */
SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW, &stat_rush_requests, 0, "");
/*
* When shutting down the syncer, run it at four times normal speed.
*/
#define SYNCER_SHUTDOWN_SPEEDUP 4
static int sync_vnode_count;
static int syncer_worklist_len;
static enum { SYNCER_RUNNING, SYNCER_SHUTTING_DOWN, SYNCER_FINAL_DELAY }
syncer_state;
/*
* Number of vnodes we want to exist at any one time. This is mostly used
* to size hash tables in vnode-related code. It is normally not used in
* getnewvnode(), as wantfreevnodes is normally nonzero.)
*
* XXX desiredvnodes is historical cruft and should not exist.
*/
int desiredvnodes;
SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
&desiredvnodes, 0, "Maximum number of vnodes");
static int minvnodes;
SYSCTL_INT(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
&minvnodes, 0, "Minimum number of vnodes");
static int vnlru_nowhere;
SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW,
&vnlru_nowhere, 0, "Number of times the vnlru process ran without success");
/* Hook for calling soft updates. */
int (*softdep_process_worklist_hook)(struct mount *);
/*
* Initialize the vnode management data structures.
*/
#ifndef MAXVNODES_MAX
#define MAXVNODES_MAX 100000
#endif
static void
vntblinit(void *dummy __unused)
{
/*
* Desiredvnodes is a function of the physical memory size and
* the kernel's heap size. Specifically, desiredvnodes scales
* in proportion to the physical memory size until two fifths
* of the kernel's heap size is consumed by vnodes and vm
* objects.
*/
desiredvnodes = min(maxproc + cnt.v_page_count / 4, 2 * vm_kmem_size /
(5 * (sizeof(struct vm_object) + sizeof(struct vnode))));
if (desiredvnodes > MAXVNODES_MAX) {
if (bootverbose)
printf("Reducing kern.maxvnodes %d -> %d\n",
desiredvnodes, MAXVNODES_MAX);
desiredvnodes = MAXVNODES_MAX;
}
minvnodes = desiredvnodes / 4;
mtx_init(&mountlist_mtx, "mountlist", NULL, MTX_DEF);
mtx_init(&mntid_mtx, "mntid", NULL, MTX_DEF);
TAILQ_INIT(&vnode_free_list);
mtx_init(&vnode_free_list_mtx, "vnode_free_list", NULL, MTX_DEF);
vnode_zone = uma_zcreate("VNODE", sizeof (struct vnode), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
vnodepoll_zone = uma_zcreate("VNODEPOLL", sizeof (struct vpollinfo),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
/*
* Initialize the filesystem syncer.
*/
syncer_workitem_pending = hashinit(syncer_maxdelay, M_VNODE,
&syncer_mask);
syncer_maxdelay = syncer_mask + 1;
mtx_init(&sync_mtx, "Syncer mtx", NULL, MTX_DEF);
}
SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vntblinit, NULL)
/*
* Mark a mount point as busy. Used to synchronize access and to delay
* unmounting. Interlock is not released on failure.
*/
int
vfs_busy(mp, flags, interlkp, td)
struct mount *mp;
int flags;
struct mtx *interlkp;
struct thread *td;
{
int lkflags;
if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
if (flags & LK_NOWAIT)
return (ENOENT);
mp->mnt_kern_flag |= MNTK_MWAIT;
/*
* Since all busy locks are shared except the exclusive
* lock granted when unmounting, the only place that a
* wakeup needs to be done is at the release of the
* exclusive lock at the end of dounmount.
*/
msleep(mp, interlkp, PVFS, "vfs_busy", 0);
return (ENOENT);
}
lkflags = LK_SHARED | LK_NOPAUSE;
if (interlkp)
lkflags |= LK_INTERLOCK;
if (lockmgr(&mp->mnt_lock, lkflags, interlkp, td))
panic("vfs_busy: unexpected lock failure");
return (0);
}
/*
* Free a busy filesystem.
*/
void
vfs_unbusy(mp, td)
struct mount *mp;
struct thread *td;
{
lockmgr(&mp->mnt_lock, LK_RELEASE, NULL, td);
}
/*
* Lookup a mount point by filesystem identifier.
*/
struct mount *
vfs_getvfs(fsid)
fsid_t *fsid;
{
register struct mount *mp;
mtx_lock(&mountlist_mtx);
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]) {
mtx_unlock(&mountlist_mtx);
return (mp);
}
}
mtx_unlock(&mountlist_mtx);
return ((struct mount *) 0);
}
/*
* Check if a user can access priveledged mount options.
*/
int
vfs_suser(struct mount *mp, struct thread *td)
{
int error;
if ((mp->mnt_flag & MNT_USER) == 0 ||
mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
if ((error = suser(td)) != 0)
return (error);
}
return (0);
}
/*
* Get a new unique fsid. Try to make its val[0] unique, since this value
* will be used to create fake device numbers for stat(). Also try (but
* not so hard) make its val[0] unique mod 2^16, since some emulators only
* support 16-bit device numbers. We end up with unique val[0]'s for the
* first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls.
*
* Keep in mind that several mounts may be running in parallel. Starting
* the search one past where the previous search terminated is both a
* micro-optimization and a defense against returning the same fsid to
* different mounts.
*/
void
vfs_getnewfsid(mp)
struct mount *mp;
{
static u_int16_t mntid_base;
fsid_t tfsid;
int mtype;
mtx_lock(&mntid_mtx);
mtype = mp->mnt_vfc->vfc_typenum;
tfsid.val[1] = mtype;
mtype = (mtype & 0xFF) << 24;
for (;;) {
tfsid.val[0] = makedev(255,
mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF));
mntid_base++;
if (vfs_getvfs(&tfsid) == NULL)
break;
}
mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
mp->mnt_stat.f_fsid.val[1] = tfsid.val[1];
mtx_unlock(&mntid_mtx);
}
/*
* Knob to control the precision of file timestamps:
*
* 0 = seconds only; nanoseconds zeroed.
* 1 = seconds and nanoseconds, accurate within 1/HZ.
* 2 = seconds and nanoseconds, truncated to microseconds.
* >=3 = seconds and nanoseconds, maximum precision.
*/
enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
static int timestamp_precision = TSP_SEC;
SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
&timestamp_precision, 0, "");
/*
* Get a current timestamp.
*/
void
vfs_timestamp(tsp)
struct timespec *tsp;
{
struct timeval tv;
switch (timestamp_precision) {
case TSP_SEC:
tsp->tv_sec = time_second;
tsp->tv_nsec = 0;
break;
case TSP_HZ:
getnanotime(tsp);
break;
case TSP_USEC:
microtime(&tv);
TIMEVAL_TO_TIMESPEC(&tv, tsp);
break;
case TSP_NSEC:
default:
nanotime(tsp);
break;
}
}
/*
* 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 = VNOVAL;
vap->va_nlink = VNOVAL;
vap->va_uid = VNOVAL;
vap->va_gid = VNOVAL;
vap->va_fsid = VNOVAL;
vap->va_fileid = VNOVAL;
vap->va_blocksize = VNOVAL;
vap->va_rdev = 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_birthtime.tv_sec = VNOVAL;
vap->va_birthtime.tv_nsec = VNOVAL;
vap->va_flags = VNOVAL;
vap->va_gen = VNOVAL;
vap->va_vaflags = 0;
}
/*
* This routine is called when we have too many vnodes. It attempts
* to free <count> vnodes and will potentially free vnodes that still
* have VM backing store (VM backing store is typically the cause
* of a vnode blowout so we want to do this). Therefore, this operation
* is not considered cheap.
*
* A number of conditions may prevent a vnode from being reclaimed.
* the buffer cache may have references on the vnode, a directory
* vnode may still have references due to the namei cache representing
* underlying files, or the vnode may be in active use. It is not
* desireable to reuse such vnodes. These conditions may cause the
* number of vnodes to reach some minimum value regardless of what
* you set kern.maxvnodes to. Do not set kern.maxvnodes too low.
*/
static int
vlrureclaim(struct mount *mp)
{
struct vnode *vp;
int done;
int trigger;
int usevnodes;
int count;
/*
* Calculate the trigger point, don't allow user
* screwups to blow us up. This prevents us from
* recycling vnodes with lots of resident pages. We
* aren't trying to free memory, we are trying to
* free vnodes.
*/
usevnodes = desiredvnodes;
if (usevnodes <= 0)
usevnodes = 1;
trigger = cnt.v_page_count * 2 / usevnodes;
done = 0;
MNT_ILOCK(mp);
count = mp->mnt_nvnodelistsize / 10 + 1;
while (count && (vp = TAILQ_FIRST(&mp->mnt_nvnodelist)) != NULL) {
TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
if (vp->v_type != VNON &&
vp->v_type != VBAD &&
VI_TRYLOCK(vp)) {
if (VMIGHTFREE(vp) && /* critical path opt */
(vp->v_object == NULL ||
vp->v_object->resident_page_count < trigger)) {
MNT_IUNLOCK(mp);
vgonel(vp, curthread);
done++;
MNT_ILOCK(mp);
} else
VI_UNLOCK(vp);
}
--count;
}
MNT_IUNLOCK(mp);
return done;
}
/*
* Attempt to recycle vnodes in a context that is always safe to block.
* Calling vlrurecycle() from the bowels of filesystem code has some
* interesting deadlock problems.
*/
static struct proc *vnlruproc;
static int vnlruproc_sig;
static void
vnlru_proc(void)
{
struct mount *mp, *nmp;
int done;
struct proc *p = vnlruproc;
struct thread *td = FIRST_THREAD_IN_PROC(p);
mtx_lock(&Giant);
EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, p,
SHUTDOWN_PRI_FIRST);
for (;;) {
kthread_suspend_check(p);
mtx_lock(&vnode_free_list_mtx);
if (numvnodes - freevnodes <= desiredvnodes * 9 / 10) {
mtx_unlock(&vnode_free_list_mtx);
vnlruproc_sig = 0;
wakeup(&vnlruproc_sig);
tsleep(vnlruproc, PVFS, "vlruwt", hz);
continue;
}
mtx_unlock(&vnode_free_list_mtx);
done = 0;
mtx_lock(&mountlist_mtx);
for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td)) {
nmp = TAILQ_NEXT(mp, mnt_list);
continue;
}
done += vlrureclaim(mp);
mtx_lock(&mountlist_mtx);
nmp = TAILQ_NEXT(mp, mnt_list);
vfs_unbusy(mp, td);
}
mtx_unlock(&mountlist_mtx);
if (done == 0) {
#if 0
/* These messages are temporary debugging aids */
if (vnlru_nowhere < 5)
printf("vnlru process getting nowhere..\n");
else if (vnlru_nowhere == 5)
printf("vnlru process messages stopped.\n");
#endif
vnlru_nowhere++;
tsleep(vnlruproc, PPAUSE, "vlrup", hz * 3);
}
}
}
static struct kproc_desc vnlru_kp = {
"vnlru",
vnlru_proc,
&vnlruproc
};
SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &vnlru_kp)
/*
* Routines having to do with the management of the vnode table.
*/
/*
* Check to see if a free vnode can be recycled. If it can,
* recycle it and return it with the vnode interlock held.
*/
static int
vtryrecycle(struct vnode *vp)
{
struct thread *td = curthread;
vm_object_t object;
struct mount *vnmp;
int error;
/* Don't recycle if we can't get the interlock */
if (!VI_TRYLOCK(vp))
return (EWOULDBLOCK);
/*
* This vnode may found and locked via some other list, if so we
* can't recycle it yet.
*/
if (vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE | LK_NOWAIT, td) != 0)
return (EWOULDBLOCK);
/*
* Don't recycle if its filesystem is being suspended.
*/
if (vn_start_write(vp, &vnmp, V_NOWAIT) != 0) {
VOP_UNLOCK(vp, 0, td);
return (EBUSY);
}
/*
* Don't recycle if we still have cached pages.
*/
if (VOP_GETVOBJECT(vp, &object) == 0) {
VM_OBJECT_LOCK(object);
if (object->resident_page_count ||
object->ref_count) {
VM_OBJECT_UNLOCK(object);
error = EBUSY;
goto done;
}
VM_OBJECT_UNLOCK(object);
}
if (LIST_FIRST(&vp->v_cache_src)) {
/*
* note: nameileafonly sysctl is temporary,
* for debugging only, and will eventually be
* removed.
*/
if (nameileafonly > 0) {
/*
* Do not reuse namei-cached directory
* vnodes that have cached
* subdirectories.
*/
if (cache_leaf_test(vp) < 0) {
error = EISDIR;
goto done;
}
} else if (nameileafonly < 0 ||
vmiodirenable == 0) {
/*
* Do not reuse namei-cached directory
* vnodes if nameileafonly is -1 or
* if VMIO backing for directories is
* turned off (otherwise we reuse them
* too quickly).
*/
error = EBUSY;
goto done;
}
}
/*
* If we got this far, we need to acquire the interlock and see if
* anyone picked up this vnode from another list. If not, we will
* mark it with XLOCK via vgonel() so that anyone who does find it
* will skip over it.
*/
VI_LOCK(vp);
if (VSHOULDBUSY(vp) && (vp->v_iflag & VI_XLOCK) == 0) {
VI_UNLOCK(vp);
error = EBUSY;
goto done;
}
mtx_lock(&vnode_free_list_mtx);
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
vp->v_iflag &= ~VI_FREE;
mtx_unlock(&vnode_free_list_mtx);
vp->v_iflag |= VI_DOOMED;
if ((vp->v_type != VBAD) || (vp->v_data != NULL)) {
VOP_UNLOCK(vp, 0, td);
vgonel(vp, td);
VI_LOCK(vp);
} else
VOP_UNLOCK(vp, 0, td);
vn_finished_write(vnmp);
return (0);
done:
VOP_UNLOCK(vp, 0, td);
vn_finished_write(vnmp);
return (error);
}
/*
* Return the next vnode from the free list.
*/
int
getnewvnode(tag, mp, vops, vpp)
const char *tag;
struct mount *mp;
vop_t **vops;
struct vnode **vpp;
{
struct vnode *vp = NULL;
struct vpollinfo *pollinfo = NULL;
struct bufobj *bo;
mtx_lock(&vnode_free_list_mtx);
/*
* Try to reuse vnodes if we hit the max. This situation only
* occurs in certain large-memory (2G+) situations. We cannot
* attempt to directly reclaim vnodes due to nasty recursion
* problems.
*/
while (numvnodes - freevnodes > desiredvnodes) {
if (vnlruproc_sig == 0) {
vnlruproc_sig = 1; /* avoid unnecessary wakeups */
wakeup(vnlruproc);
}
mtx_unlock(&vnode_free_list_mtx);
tsleep(&vnlruproc_sig, PVFS, "vlruwk", hz);
mtx_lock(&vnode_free_list_mtx);
}
/*
* Attempt to reuse a vnode already on the free list, allocating
* a new vnode if we can't find one or if we have not reached a
* good minimum for good LRU performance.
*/
if (freevnodes >= wantfreevnodes && numvnodes >= minvnodes) {
int error;
int count;
for (count = 0; count < freevnodes; count++) {
vp = TAILQ_FIRST(&vnode_free_list);
KASSERT(vp->v_usecount == 0 &&
(vp->v_iflag & VI_DOINGINACT) == 0,
("getnewvnode: free vnode isn't"));
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
mtx_unlock(&vnode_free_list_mtx);
error = vtryrecycle(vp);
mtx_lock(&vnode_free_list_mtx);
if (error == 0)
break;
vp = NULL;
}
}
if (vp) {
freevnodes--;
bo = &vp->v_bufobj;
mtx_unlock(&vnode_free_list_mtx);
#ifdef INVARIANTS
{
if (vp->v_data)
printf("cleaned vnode isn't, "
"address %p, inode %p\n",
vp, vp->v_data);
if (bo->bo_numoutput)
panic("Clean vnode has pending I/O's");
if (vp->v_writecount != 0)
panic("Non-zero write count");
}
#endif
if ((pollinfo = vp->v_pollinfo) != NULL) {
/*
* To avoid lock order reversals, the call to
* uma_zfree() must be delayed until the vnode
* interlock is released.
*/
vp->v_pollinfo = NULL;
}
#ifdef MAC
mac_destroy_vnode(vp);
#endif
vp->v_iflag = 0;
vp->v_vflag = 0;
vp->v_lastw = 0;
vp->v_lasta = 0;
vp->v_cstart = 0;
vp->v_clen = 0;
vp->v_socket = 0;
lockdestroy(vp->v_vnlock);
lockinit(vp->v_vnlock, PVFS, tag, VLKTIMEOUT, LK_NOPAUSE);
KASSERT(bo->bo_clean.bv_cnt == 0, ("cleanbufcnt not 0"));
KASSERT(bo->bo_clean.bv_root == NULL, ("cleanblkroot not NULL"));
KASSERT(bo->bo_dirty.bv_cnt == 0, ("dirtybufcnt not 0"));
KASSERT(bo->bo_dirty.bv_root == NULL, ("dirtyblkroot not NULL"));
} else {
numvnodes++;
mtx_unlock(&vnode_free_list_mtx);
vp = (struct vnode *) uma_zalloc(vnode_zone, M_WAITOK|M_ZERO);
mtx_init(&vp->v_interlock, "vnode interlock", NULL, MTX_DEF);
VI_LOCK(vp);
vp->v_dd = vp;
bo = &vp->v_bufobj;
bo->bo_mtx = &vp->v_interlock;
vp->v_vnlock = &vp->v_lock;
lockinit(vp->v_vnlock, PVFS, tag, VLKTIMEOUT, LK_NOPAUSE);
cache_purge(vp); /* Sets up v_id. */
LIST_INIT(&vp->v_cache_src);
TAILQ_INIT(&vp->v_cache_dst);
}
TAILQ_INIT(&bo->bo_clean.bv_hd);
TAILQ_INIT(&bo->bo_dirty.bv_hd);
vp->v_type = VNON;
vp->v_tag = tag;
vp->v_op = vops;
*vpp = vp;
vp->v_usecount = 1;
vp->v_data = 0;
vp->v_cachedid = -1;
VI_UNLOCK(vp);
if (pollinfo != NULL) {
knlist_destroy(&pollinfo->vpi_selinfo.si_note);
mtx_destroy(&pollinfo->vpi_lock);
uma_zfree(vnodepoll_zone, pollinfo);
}
#ifdef MAC
mac_init_vnode(vp);
if (mp != NULL && (mp->mnt_flag & MNT_MULTILABEL) == 0)
mac_associate_vnode_singlelabel(mp, vp);
#endif
delmntque(vp);
if (mp != NULL) {
insmntque(vp, mp);
vp->v_bsize = mp->mnt_stat.f_iosize;
}
return (0);
}
/*
* Delete from old mount point vnode list, if on one.
*/
static void
delmntque(struct vnode *vp)
{
struct mount *mp;
if (vp->v_mount == NULL)
return;
mp = vp->v_mount;
MNT_ILOCK(mp);
vp->v_mount = NULL;
KASSERT(mp->mnt_nvnodelistsize > 0,
("bad mount point vnode list size"));
TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
mp->mnt_nvnodelistsize--;
MNT_IUNLOCK(mp);
}
/*
* Insert into list of vnodes for the new mount point, if available.
*/
static void
insmntque(struct vnode *vp, struct mount *mp)
{
vp->v_mount = mp;
KASSERT(mp != NULL, ("Don't call insmntque(foo, NULL)"));
MNT_ILOCK(vp->v_mount);
TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
mp->mnt_nvnodelistsize++;
MNT_IUNLOCK(vp->v_mount);
}
/*
* Flush out and invalidate all buffers associated with a vnode.
* Called with the underlying object locked.
*/
int
vinvalbuf(vp, flags, cred, td, slpflag, slptimeo)
struct vnode *vp;
int flags;
struct ucred *cred;
struct thread *td;
int slpflag, slptimeo;
{
struct buf *blist;
int error;
vm_object_t object;
struct bufobj *bo;
GIANT_REQUIRED;
ASSERT_VOP_LOCKED(vp, "vinvalbuf");
VI_LOCK(vp);
bo = &vp->v_bufobj;
if (flags & V_SAVE) {
error = bufobj_wwait(bo, slpflag, slptimeo);
if (error) {
VI_UNLOCK(vp);
return (error);
}
if (bo->bo_dirty.bv_cnt > 0) {
VI_UNLOCK(vp);
if ((error = VOP_FSYNC(vp, cred, MNT_WAIT, td)) != 0)
return (error);
/*
* XXX We could save a lock/unlock if this was only
* enabled under INVARIANTS
*/
VI_LOCK(vp);
if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0)
panic("vinvalbuf: dirty bufs");
}
}
/*
* If you alter this loop please notice that interlock is dropped and
* reacquired in flushbuflist. Special care is needed to ensure that
* no race conditions occur from this.
*/
for (error = 0;;) {
if ((blist = TAILQ_FIRST(&vp->v_cleanblkhd)) != 0 &&
flushbuflist(blist, flags, vp, slpflag, slptimeo, &error)) {
if (error)
break;
continue;
}
if ((blist = TAILQ_FIRST(&vp->v_dirtyblkhd)) != 0 &&
flushbuflist(blist, flags, vp, slpflag, slptimeo, &error)) {
if (error)
break;
continue;
}
break;
}
if (error) {
VI_UNLOCK(vp);
return (error);
}
/*
* Wait for I/O to complete. XXX needs cleaning up. The vnode can
* have write I/O in-progress but if there is a VM object then the
* VM object can also have read-I/O in-progress.
*/
do {
bufobj_wwait(bo, 0, 0);
VI_UNLOCK(vp);
if (VOP_GETVOBJECT(vp, &object) == 0) {
VM_OBJECT_LOCK(object);
vm_object_pip_wait(object, "vnvlbx");
VM_OBJECT_UNLOCK(object);
}
VI_LOCK(vp);
} while (vp->v_numoutput > 0);
VI_UNLOCK(vp);
/*
* Destroy the copy in the VM cache, too.
*/
if (VOP_GETVOBJECT(vp, &object) == 0) {
VM_OBJECT_LOCK(object);
vm_object_page_remove(object, 0, 0,
(flags & V_SAVE) ? TRUE : FALSE);
VM_OBJECT_UNLOCK(object);
}
#ifdef INVARIANTS
VI_LOCK(vp);
if ((flags & (V_ALT | V_NORMAL)) == 0 &&
(!TAILQ_EMPTY(&vp->v_dirtyblkhd) ||
!TAILQ_EMPTY(&vp->v_cleanblkhd)))
panic("vinvalbuf: flush failed");
VI_UNLOCK(vp);
#endif
return (0);
}
/*
* Flush out buffers on the specified list.
*
*/
static int
flushbuflist(blist, flags, vp, slpflag, slptimeo, errorp)
struct buf *blist;
int flags;
struct vnode *vp;
int slpflag, slptimeo;
int *errorp;
{
struct buf *bp, *nbp;
int found, error;
ASSERT_VI_LOCKED(vp, "flushbuflist");
for (found = 0, bp = blist; bp; bp = nbp) {
nbp = TAILQ_NEXT(bp, b_bobufs);
if (((flags & V_NORMAL) && (bp->b_xflags & BX_ALTDATA)) ||
((flags & V_ALT) && (bp->b_xflags & BX_ALTDATA) == 0)) {
continue;
}
found += 1;
error = BUF_TIMELOCK(bp,
LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK, VI_MTX(vp),
"flushbuf", slpflag, slptimeo);
if (error) {
if (error != ENOLCK)
*errorp = error;
goto done;
}
/*
* 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. Note that vfs_bio_awrite expects
* buffers to reside on a queue, while bwrite and
* brelse do not.
*/
if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
(flags & V_SAVE)) {
if (bp->b_vp == vp) {
if (bp->b_flags & B_CLUSTEROK) {
vfs_bio_awrite(bp);
} else {
bremfree(bp);
bp->b_flags |= B_ASYNC;
bwrite(bp);
}
} else {
bremfree(bp);
(void) bwrite(bp);
}
goto done;
}
bremfree(bp);
bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
bp->b_flags &= ~B_ASYNC;
brelse(bp);
VI_LOCK(vp);
}
return (found);
done:
VI_LOCK(vp);
return (found);
}
/*
* Truncate a file's buffer and pages to a specified length. This
* is in lieu of the old vinvalbuf mechanism, which performed unneeded
* sync activity.
*/
int
vtruncbuf(struct vnode *vp, struct ucred *cred, struct thread *td, off_t length, int blksize)
{
struct buf *bp, *nbp;
int anyfreed;
int trunclbn;
struct bufobj *bo;
/*
* Round up to the *next* lbn.
*/
trunclbn = (length + blksize - 1) / blksize;
ASSERT_VOP_LOCKED(vp, "vtruncbuf");
restart:
VI_LOCK(vp);
bo = &vp->v_bufobj;
anyfreed = 1;
for (;anyfreed;) {
anyfreed = 0;
TAILQ_FOREACH_SAFE(bp, &bo->bo_clean.bv_hd, b_bobufs, nbp) {
if (bp->b_lblkno < trunclbn)
continue;
if (BUF_LOCK(bp,
LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
VI_MTX(vp)) == ENOLCK)
goto restart;
bremfree(bp);
bp->b_flags |= (B_INVAL | B_RELBUF);
bp->b_flags &= ~B_ASYNC;
brelse(bp);
anyfreed = 1;
if (nbp != NULL &&
(((nbp->b_xflags & BX_VNCLEAN) == 0) ||
(nbp->b_vp != vp) ||
(nbp->b_flags & B_DELWRI))) {
goto restart;
}
VI_LOCK(vp);
}
TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
if (bp->b_lblkno < trunclbn)
continue;
if (BUF_LOCK(bp,
LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
VI_MTX(vp)) == ENOLCK)
goto restart;
bremfree(bp);
bp->b_flags |= (B_INVAL | B_RELBUF);
bp->b_flags &= ~B_ASYNC;
brelse(bp);
anyfreed = 1;
if (nbp != NULL &&
(((nbp->b_xflags & BX_VNDIRTY) == 0) ||
(nbp->b_vp != vp) ||
(nbp->b_flags & B_DELWRI) == 0)) {
goto restart;
}
VI_LOCK(vp);
}
}
if (length > 0) {
restartsync:
TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
if (bp->b_lblkno > 0)
continue;
/*
* Since we hold the vnode lock this should only
* fail if we're racing with the buf daemon.
*/
if (BUF_LOCK(bp,
LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
VI_MTX(vp)) == ENOLCK) {
goto restart;
}
KASSERT((bp->b_flags & B_DELWRI),
("buf(%p) on dirty queue without DELWRI", bp));
bremfree(bp);
bawrite(bp);
VI_LOCK(vp);
goto restartsync;
}
}
bufobj_wwait(bo, 0, 0);
VI_UNLOCK(vp);
vnode_pager_setsize(vp, length);
return (0);
}
/*
* buf_splay() - splay tree core for the clean/dirty list of buffers in
* a vnode.
*
* NOTE: We have to deal with the special case of a background bitmap
* buffer, a situation where two buffers will have the same logical
* block offset. We want (1) only the foreground buffer to be accessed
* in a lookup and (2) must differentiate between the foreground and
* background buffer in the splay tree algorithm because the splay
* tree cannot normally handle multiple entities with the same 'index'.
* We accomplish this by adding differentiating flags to the splay tree's
* numerical domain.
*/
static
struct buf *
buf_splay(daddr_t lblkno, b_xflags_t xflags, struct buf *root)
{
struct buf dummy;
struct buf *lefttreemax, *righttreemin, *y;
if (root == NULL)
return (NULL);
lefttreemax = righttreemin = &dummy;
for (;;) {
if (lblkno < root->b_lblkno ||
(lblkno == root->b_lblkno &&
(xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
if ((y = root->b_left) == NULL)
break;
if (lblkno < y->b_lblkno) {
/* Rotate right. */
root->b_left = y->b_right;
y->b_right = root;
root = y;
if ((y = root->b_left) == NULL)
break;
}
/* Link into the new root's right tree. */
righttreemin->b_left = root;
righttreemin = root;
} else if (lblkno > root->b_lblkno ||
(lblkno == root->b_lblkno &&
(xflags & BX_BKGRDMARKER) > (root->b_xflags & BX_BKGRDMARKER))) {
if ((y = root->b_right) == NULL)
break;
if (lblkno > y->b_lblkno) {
/* Rotate left. */
root->b_right = y->b_left;
y->b_left = root;
root = y;
if ((y = root->b_right) == NULL)
break;
}
/* Link into the new root's left tree. */
lefttreemax->b_right = root;
lefttreemax = root;
} else {
break;
}
root = y;
}
/* Assemble the new root. */
lefttreemax->b_right = root->b_left;
righttreemin->b_left = root->b_right;
root->b_left = dummy.b_right;
root->b_right = dummy.b_left;
return (root);
}
static void
buf_vlist_remove(struct buf *bp)
{
struct buf *root;
struct bufv *bv;
KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
ASSERT_BO_LOCKED(bp->b_bufobj);
if (bp->b_xflags & BX_VNDIRTY)
bv = &bp->b_bufobj->bo_dirty;
else
bv = &bp->b_bufobj->bo_clean;
if (bp != bv->bv_root) {
root = buf_splay(bp->b_lblkno, bp->b_xflags, bv->bv_root);
KASSERT(root == bp, ("splay lookup failed in remove"));
}
if (bp->b_left == NULL) {
root = bp->b_right;
} else {
root = buf_splay(bp->b_lblkno, bp->b_xflags, bp->b_left);
root->b_right = bp->b_right;
}
bv->bv_root = root;
TAILQ_REMOVE(&bv->bv_hd, bp, b_bobufs);
bv->bv_cnt--;
bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
}
/*
* Add the buffer to the sorted clean or dirty block list using a
* splay tree algorithm.
*
* NOTE: xflags is passed as a constant, optimizing this inline function!
*/
static void
buf_vlist_add(struct buf *bp, struct bufobj *bo, b_xflags_t xflags)
{
struct buf *root;
struct bufv *bv;
ASSERT_BO_LOCKED(bo);
bp->b_xflags |= xflags;
if (xflags & BX_VNDIRTY)
bv = &bo->bo_dirty;
else
bv = &bo->bo_clean;
root = buf_splay(bp->b_lblkno, bp->b_xflags, bv->bv_root);
if (root == NULL) {
bp->b_left = NULL;
bp->b_right = NULL;
TAILQ_INSERT_TAIL(&bv->bv_hd, bp, b_bobufs);
} else if (bp->b_lblkno < root->b_lblkno ||
(bp->b_lblkno == root->b_lblkno &&
(bp->b_xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
bp->b_left = root->b_left;
bp->b_right = root;
root->b_left = NULL;
TAILQ_INSERT_BEFORE(root, bp, b_bobufs);
} else {
bp->b_right = root->b_right;
bp->b_left = root;
root->b_right = NULL;
TAILQ_INSERT_AFTER(&bv->bv_hd, root, bp, b_bobufs);
}
bv->bv_cnt++;
bv->bv_root = bp;
}
/*
* Lookup a buffer using the splay tree. Note that we specifically avoid
* shadow buffers used in background bitmap writes.
*
* This code isn't quite efficient as it could be because we are maintaining
* two sorted lists and do not know which list the block resides in.
*
* During a "make buildworld" the desired buffer is found at one of
* the roots more than 60% of the time. Thus, checking both roots
* before performing either splay eliminates unnecessary splays on the
* first tree splayed.
*/
struct buf *
gbincore(struct bufobj *bo, daddr_t lblkno)
{
struct buf *bp;
GIANT_REQUIRED;
ASSERT_BO_LOCKED(bo);
if ((bp = bo->bo_clean.bv_root) != NULL &&
bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
return (bp);
if ((bp = bo->bo_dirty.bv_root) != NULL &&
bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
return (bp);
if ((bp = bo->bo_clean.bv_root) != NULL) {
bo->bo_clean.bv_root = bp = buf_splay(lblkno, 0, bp);
if (bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
return (bp);
}
if ((bp = bo->bo_dirty.bv_root) != NULL) {
bo->bo_dirty.bv_root = bp = buf_splay(lblkno, 0, bp);
if (bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
return (bp);
}
return (NULL);
}
/*
* Associate a buffer with a vnode.
*/
void
bgetvp(struct vnode *vp, struct buf *bp)
{
KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0,
("bgetvp: bp already attached! %p", bp));
ASSERT_VI_LOCKED(vp, "bgetvp");
vholdl(vp);
bp->b_vp = vp;
bp->b_bufobj = &vp->v_bufobj;
bp->b_dev = vn_todev(vp);
/*
* Insert onto list for new vnode.
*/
buf_vlist_add(bp, &vp->v_bufobj, BX_VNCLEAN);
}
/*
* Disassociate a buffer from a vnode.
*/
void
brelvp(struct buf *bp)
{
struct bufobj *bo;
struct vnode *vp;
KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
/*
* Delete from old vnode list, if on one.
*/
vp = bp->b_vp;
VI_LOCK(vp);
bo = bp->b_bufobj;
if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
buf_vlist_remove(bp);
if ((vp->v_iflag & VI_ONWORKLST) && TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
vp->v_iflag &= ~VI_ONWORKLST;
mtx_lock(&sync_mtx);
LIST_REMOVE(vp, v_synclist);
syncer_worklist_len--;
mtx_unlock(&sync_mtx);
}
vdropl(vp);
bp->b_vp = NULL;
bp->b_bufobj = NULL;
if (bp->b_object)
bp->b_object = NULL;
VI_UNLOCK(vp);
}
/*
* Add an item to the syncer work queue.
*/
static void
vn_syncer_add_to_worklist(struct vnode *vp, int delay)
{
int slot;
ASSERT_VI_LOCKED(vp, "vn_syncer_add_to_worklist");
mtx_lock(&sync_mtx);
if (vp->v_iflag & VI_ONWORKLST)
LIST_REMOVE(vp, v_synclist);
else {
vp->v_iflag |= VI_ONWORKLST;
syncer_worklist_len++;
}
if (delay > syncer_maxdelay - 2)
delay = syncer_maxdelay - 2;
slot = (syncer_delayno + delay) & syncer_mask;
LIST_INSERT_HEAD(&syncer_workitem_pending[slot], vp, v_synclist);
mtx_unlock(&sync_mtx);
}
static int
sysctl_vfs_worklist_len(SYSCTL_HANDLER_ARGS)
{
int error, len;
mtx_lock(&sync_mtx);
len = syncer_worklist_len - sync_vnode_count;
mtx_unlock(&sync_mtx);
error = SYSCTL_OUT(req, &len, sizeof(len));
return (error);
}
SYSCTL_PROC(_vfs, OID_AUTO, worklist_len, CTLTYPE_INT | CTLFLAG_RD, NULL, 0,
sysctl_vfs_worklist_len, "I", "Syncer thread worklist length");
struct proc *updateproc;
static void sched_sync(void);
static struct kproc_desc up_kp = {
"syncer",
sched_sync,
&updateproc
};
SYSINIT(syncer, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp)
/*
* System filesystem synchronizer daemon.
*/
static void
sched_sync(void)
{
struct synclist *next;
struct synclist *slp;
struct vnode *vp;
struct mount *mp;
long starttime;
struct thread *td = FIRST_THREAD_IN_PROC(updateproc);
static int dummychan;
int last_work_seen;
int net_worklist_len;
int syncer_final_iter;
int first_printf;
mtx_lock(&Giant);
last_work_seen = 0;
syncer_final_iter = 0;
first_printf = 1;
syncer_state = SYNCER_RUNNING;
starttime = time_second;
EVENTHANDLER_REGISTER(shutdown_pre_sync, syncer_shutdown, td->td_proc,
SHUTDOWN_PRI_LAST);
for (;;) {
mtx_lock(&sync_mtx);
if (syncer_state == SYNCER_FINAL_DELAY &&
syncer_final_iter == 0) {
mtx_unlock(&sync_mtx);
kthread_suspend_check(td->td_proc);
mtx_lock(&sync_mtx);
}
net_worklist_len = syncer_worklist_len - sync_vnode_count;
if (syncer_state != SYNCER_RUNNING &&
starttime != time_second) {
if (first_printf) {
printf("\nSyncing disks, vnodes remaining...");
first_printf = 0;
}
printf("%d ", net_worklist_len);
}
starttime = time_second;
/*
* Push files whose dirty time has expired. Be careful
* of interrupt race on slp queue.
*
* Skip over empty worklist slots when shutting down.
*/
do {
slp = &syncer_workitem_pending[syncer_delayno];
syncer_delayno += 1;
if (syncer_delayno == syncer_maxdelay)
syncer_delayno = 0;
next = &syncer_workitem_pending[syncer_delayno];
/*
* If the worklist has wrapped since the
* it was emptied of all but syncer vnodes,
* switch to the FINAL_DELAY state and run
* for one more second.
*/
if (syncer_state == SYNCER_SHUTTING_DOWN &&
net_worklist_len == 0 &&
last_work_seen == syncer_delayno) {
syncer_state = SYNCER_FINAL_DELAY;
syncer_final_iter = SYNCER_SHUTDOWN_SPEEDUP;
}
} while (syncer_state != SYNCER_RUNNING && LIST_EMPTY(slp) &&
syncer_worklist_len > 0);
/*
* Keep track of the last time there was anything
* on the worklist other than syncer vnodes.
* Return to the SHUTTING_DOWN state if any
* new work appears.
*/
if (net_worklist_len > 0 || syncer_state == SYNCER_RUNNING)
last_work_seen = syncer_delayno;
if (net_worklist_len > 0 && syncer_state == SYNCER_FINAL_DELAY)
syncer_state = SYNCER_SHUTTING_DOWN;
while ((vp = LIST_FIRST(slp)) != NULL) {
if (VOP_ISLOCKED(vp, NULL) != 0 ||
vn_start_write(vp, &mp, V_NOWAIT) != 0) {
LIST_REMOVE(vp, v_synclist);
LIST_INSERT_HEAD(next, vp, v_synclist);
continue;
}
if (VI_TRYLOCK(vp) == 0) {
LIST_REMOVE(vp, v_synclist);
LIST_INSERT_HEAD(next, vp, v_synclist);
vn_finished_write(mp);
continue;
}
/*
* We use vhold in case the vnode does not
* successfully sync. vhold prevents the vnode from
* going away when we unlock the sync_mtx so that
* we can acquire the vnode interlock.
*/
vholdl(vp);
mtx_unlock(&sync_mtx);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_INTERLOCK, td);
(void) VOP_FSYNC(vp, td->td_ucred, MNT_LAZY, td);
VOP_UNLOCK(vp, 0, td);
vn_finished_write(mp);
VI_LOCK(vp);
if ((vp->v_iflag & VI_ONWORKLST) != 0) {
/*
* Put us back on the worklist. The worklist
* routine will remove us from our current
* position and then add us back in at a later
* position.
*/
vn_syncer_add_to_worklist(vp, syncdelay);
}
vdropl(vp);
VI_UNLOCK(vp);
mtx_lock(&sync_mtx);
}
if (syncer_state == SYNCER_FINAL_DELAY && syncer_final_iter > 0)
syncer_final_iter--;
mtx_unlock(&sync_mtx);
/*
* Do soft update processing.
*/
if (softdep_process_worklist_hook != NULL)
(*softdep_process_worklist_hook)(NULL);
/*
* The variable rushjob allows the kernel to speed up the
* processing of the filesystem syncer process. A rushjob
* value of N tells the filesystem syncer to process the next
* N seconds worth of work on its queue ASAP. Currently rushjob
* is used by the soft update code to speed up the filesystem
* syncer process when the incore state is getting so far
* ahead of the disk that the kernel memory pool is being
* threatened with exhaustion.
*/
mtx_lock(&sync_mtx);
if (rushjob > 0) {
rushjob -= 1;
mtx_unlock(&sync_mtx);
continue;
}
mtx_unlock(&sync_mtx);
/*
* Just sleep for a short period if time between
* iterations when shutting down to allow some I/O
* to happen.
*
* If it has taken us less than a second to process the
* current work, then wait. Otherwise start right over
* again. We can still lose time if any single round
* takes more than two seconds, but it does not really
* matter as we are just trying to generally pace the
* filesystem activity.
*/
if (syncer_state != SYNCER_RUNNING)
tsleep(&dummychan, PPAUSE, "syncfnl",
hz / SYNCER_SHUTDOWN_SPEEDUP);
else if (time_second == starttime)
tsleep(&lbolt, PPAUSE, "syncer", 0);
}
}
/*
* Request the syncer daemon to speed up its work.
* We never push it to speed up more than half of its
* normal turn time, otherwise it could take over the cpu.
*/
int
speedup_syncer()
{
struct thread *td;
int ret = 0;
td = FIRST_THREAD_IN_PROC(updateproc);
sleepq_remove(td, &lbolt);
mtx_lock(&sync_mtx);
if (rushjob < syncdelay / 2) {
rushjob += 1;
stat_rush_requests += 1;
ret = 1;
}
mtx_unlock(&sync_mtx);
return (ret);
}
/*
* Tell the syncer to speed up its work and run though its work
* list several times, then tell it to shut down.
*/
static void
syncer_shutdown(void *arg, int howto)
{
struct thread *td;
if (howto & RB_NOSYNC)
return;
td = FIRST_THREAD_IN_PROC(updateproc);
sleepq_remove(td, &lbolt);
mtx_lock(&sync_mtx);
syncer_state = SYNCER_SHUTTING_DOWN;
rushjob = 0;
mtx_unlock(&sync_mtx);
kproc_shutdown(arg, howto);
}
/*
* Associate a p-buffer with a vnode.
*
* Also sets B_PAGING flag to indicate that vnode is not fully associated
* with the buffer. i.e. the bp has not been linked into the vnode or
* ref-counted.
*/
void
pbgetvp(vp, bp)
register struct vnode *vp;
register struct buf *bp;
{
KASSERT(bp->b_vp == NULL, ("pbgetvp: not free"));
bp->b_vp = vp;
bp->b_object = vp->v_object;
bp->b_flags |= B_PAGING;
bp->b_dev = vn_todev(vp);
bp->b_bufobj = &vp->v_bufobj;
}
/*
* Disassociate a p-buffer from a vnode.
*/
void
pbrelvp(bp)
register struct buf *bp;
{
KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL"));
KASSERT(bp->b_bufobj != NULL, ("pbrelvp: NULL bufobj"));
/* XXX REMOVE ME */
BO_LOCK(bp->b_bufobj);
if (TAILQ_NEXT(bp, b_bobufs) != NULL) {
panic(
"relpbuf(): b_vp was probably reassignbuf()d %p %x",
bp,
(int)bp->b_flags
);
}
BO_UNLOCK(bp->b_bufobj);
bp->b_vp = NULL;
bp->b_object = NULL;
bp->b_bufobj = NULL;
bp->b_flags &= ~B_PAGING;
}
/*
* 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(struct buf *bp)
{
struct vnode *vp;
struct bufobj *bo;
int delay;
vp = bp->b_vp;
bo = bp->b_bufobj;
++reassignbufcalls;
/*
* B_PAGING flagged buffers cannot be reassigned because their vp
* is not fully linked in.
*/
if (bp->b_flags & B_PAGING)
panic("cannot reassign paging buffer");
/*
* Delete from old vnode list, if on one.
*/
VI_LOCK(vp);
if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
buf_vlist_remove(bp);
/*
* If dirty, put on list of dirty buffers; otherwise insert onto list
* of clean buffers.
*/
if (bp->b_flags & B_DELWRI) {
if ((vp->v_iflag & VI_ONWORKLST) == 0) {
switch (vp->v_type) {
case VDIR:
delay = dirdelay;
break;
case VCHR:
delay = metadelay;
break;
default:
delay = filedelay;
}
vn_syncer_add_to_worklist(vp, delay);
}
buf_vlist_add(bp, bo, BX_VNDIRTY);
} else {
buf_vlist_add(bp, bo, BX_VNCLEAN);
if ((vp->v_iflag & VI_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
mtx_lock(&sync_mtx);
LIST_REMOVE(vp, v_synclist);
syncer_worklist_len--;
mtx_unlock(&sync_mtx);
vp->v_iflag &= ~VI_ONWORKLST;
}
}
VI_UNLOCK(vp);
}
/*
* Create a vnode for a device.
* Used for mounting the root filesystem.
*/
int
bdevvp(dev, vpp)
struct cdev *dev;
struct vnode **vpp;
{
register struct vnode *vp;
struct vnode *nvp;
int error;
if (dev == NULL) {
*vpp = NULLVP;
return (ENXIO);
}
if (vfinddev(dev, vpp))
return (0);
error = getnewvnode("none", (struct mount *)0, devfs_specop_p, &nvp);
if (error) {
*vpp = NULLVP;
return (error);
}
vp = nvp;
vp->v_type = VCHR;
vp->v_bsize = DEV_BSIZE;
addalias(vp, dev);
*vpp = vp;
return (0);
}
static void
v_incr_usecount(struct vnode *vp, int delta)
{
vp->v_usecount += delta;
if (vp->v_type == VCHR && vp->v_rdev != NULL) {
dev_lock();
vp->v_rdev->si_usecount += delta;
dev_unlock();
}
}
/*
* Add vnode to the alias list hung off the struct cdev *.
*
* The reason for this gunk is that multiple vnodes can reference
* the same physical device, so checking vp->v_usecount to see
* how many users there are is inadequate; the v_usecount for
* the vnodes need to be accumulated. vcount() does that.
*/
struct vnode *
addaliasu(nvp, nvp_rdev)
struct vnode *nvp;
dev_t nvp_rdev;
{
struct vnode *ovp;
vop_t **ops;
struct cdev *dev;
if (nvp->v_type == VBLK)
return (nvp);
if (nvp->v_type != VCHR)
panic("addaliasu on non-special vnode");
dev = findcdev(nvp_rdev);
if (dev == NULL)
return (nvp);
/*
* Check to see if we have a bdevvp vnode with no associated
* filesystem. If so, we want to associate the filesystem of
* the new newly instigated vnode with the bdevvp vnode and
* discard the newly created vnode rather than leaving the
* bdevvp vnode lying around with no associated filesystem.
*/
if (vfinddev(dev, &ovp) == 0 || ovp->v_data != NULL) {
addalias(nvp, dev);
return (nvp);
}
/*
* Discard unneeded vnode, but save its node specific data.
* Note that if there is a lock, it is carried over in the
* node specific data to the replacement vnode.
*/
vref(ovp);
ovp->v_data = nvp->v_data;
ovp->v_tag = nvp->v_tag;
nvp->v_data = NULL;
lockdestroy(ovp->v_vnlock);
lockinit(ovp->v_vnlock, PVFS, nvp->v_vnlock->lk_wmesg,
nvp->v_vnlock->lk_timo, nvp->v_vnlock->lk_flags & LK_EXTFLG_MASK);
ops = ovp->v_op;
ovp->v_op = nvp->v_op;
if (VOP_ISLOCKED(nvp, curthread)) {
VOP_UNLOCK(nvp, 0, curthread);
vn_lock(ovp, LK_EXCLUSIVE | LK_RETRY, curthread);
}
nvp->v_op = ops;
delmntque(ovp);
insmntque(ovp, nvp->v_mount);
vrele(nvp);
vgone(nvp);
return (ovp);
}
/* This is a local helper function that do the same as addaliasu, but for a
* struct cdev *instead of an dev_t. */
static void
addalias(nvp, dev)
struct vnode *nvp;
struct cdev *dev;
{
KASSERT(nvp->v_type == VCHR, ("addalias on non-special vnode"));
VI_LOCK(nvp);
dev_lock();
dev->si_refcount++;
nvp->v_rdev = dev;
SLIST_INSERT_HEAD(&dev->si_hlist, nvp, v_specnext);
dev->si_usecount += nvp->v_usecount;
dev_unlock();
VI_UNLOCK(nvp);
}
/*
* Grab a particular vnode from the free list, increment its
* reference count and lock it. The vnode lock bit is set if 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 filesystem type).
*/
int
vget(vp, flags, td)
register struct vnode *vp;
int flags;
struct thread *td;
{
int error;
/*
* 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 VI_XLOCK flag is set.
*/
if ((flags & LK_INTERLOCK) == 0)
VI_LOCK(vp);
if (vp->v_iflag & VI_XLOCK && vp->v_vxthread != curthread) {
if ((flags & LK_NOWAIT) == 0) {
vp->v_iflag |= VI_XWANT;
msleep(vp, VI_MTX(vp), PINOD | PDROP, "vget", 0);
return (ENOENT);
}
VI_UNLOCK(vp);
return (EBUSY);
}
v_incr_usecount(vp, 1);
if (VSHOULDBUSY(vp))
vbusy(vp);
if (flags & LK_TYPE_MASK) {
if ((error = vn_lock(vp, flags | LK_INTERLOCK, td)) != 0) {
/*
* must expand vrele here because we do not want
* to call VOP_INACTIVE if the reference count
* drops back to zero since it was never really
* active. We must remove it from the free list
* before sleeping so that multiple processes do
* not try to recycle it.
*/
VI_LOCK(vp);
v_incr_usecount(vp, -1);
if (VSHOULDFREE(vp))
vfree(vp);
else
vlruvp(vp);
VI_UNLOCK(vp);
}
return (error);
}
VI_UNLOCK(vp);
return (0);
}
/*
* Increase the reference count of a vnode.
*/
void
vref(struct vnode *vp)
{
VI_LOCK(vp);
v_incr_usecount(vp, 1);
VI_UNLOCK(vp);
}
/*
* Return reference count of a vnode.
*
* The results of this call are only guaranteed when some mechanism other
* than the VI lock is used to stop other processes from gaining references
* to the vnode. This may be the case if the caller holds the only reference.
* This is also useful when stale data is acceptable as race conditions may
* be accounted for by some other means.
*/
int
vrefcnt(struct vnode *vp)
{
int usecnt;
VI_LOCK(vp);
usecnt = vp->v_usecount;
VI_UNLOCK(vp);
return (usecnt);
}
/*
* Vnode put/release.
* If count drops to zero, call inactive routine and return to freelist.
*/
void
vrele(vp)
struct vnode *vp;
{
struct thread *td = curthread; /* XXX */
GIANT_REQUIRED;
KASSERT(vp != NULL, ("vrele: null vp"));
VI_LOCK(vp);
/* Skip this v_writecount check if we're going to panic below. */
KASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1,
("vrele: missed vn_close"));
if (vp->v_usecount > 1 || ((vp->v_iflag & VI_DOINGINACT) &&
vp->v_usecount == 1)) {
v_incr_usecount(vp, -1);
VI_UNLOCK(vp);
return;
}
if (vp->v_usecount == 1) {
v_incr_usecount(vp, -1);
/*
* We must call VOP_INACTIVE with the node locked. Mark
* as VI_DOINGINACT to avoid recursion.
*/
if (vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK, td) == 0) {
VI_LOCK(vp);
vp->v_iflag |= VI_DOINGINACT;
VI_UNLOCK(vp);
VOP_INACTIVE(vp, td);
VI_LOCK(vp);
KASSERT(vp->v_iflag & VI_DOINGINACT,
("vrele: lost VI_DOINGINACT"));
vp->v_iflag &= ~VI_DOINGINACT;
} else
VI_LOCK(vp);
if (VSHOULDFREE(vp))
vfree(vp);
else
vlruvp(vp);
VI_UNLOCK(vp);
} else {
#ifdef DIAGNOSTIC
vprint("vrele: negative ref count", vp);
#endif
VI_UNLOCK(vp);
panic("vrele: negative ref cnt");
}
}
/*
* Release an already locked vnode. This give the same effects as
* unlock+vrele(), but takes less time and avoids releasing and
* re-aquiring the lock (as vrele() aquires the lock internally.)
*/
void
vput(vp)
struct vnode *vp;
{
struct thread *td = curthread; /* XXX */
GIANT_REQUIRED;
KASSERT(vp != NULL, ("vput: null vp"));
VI_LOCK(vp);
/* Skip this v_writecount check if we're going to panic below. */
KASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1,
("vput: missed vn_close"));
if (vp->v_usecount > 1 || ((vp->v_iflag & VI_DOINGINACT) &&
vp->v_usecount == 1)) {
v_incr_usecount(vp, -1);
VOP_UNLOCK(vp, LK_INTERLOCK, td);
return;
}
if (vp->v_usecount == 1) {
v_incr_usecount(vp, -1);
/*
* We must call VOP_INACTIVE with the node locked, so
* we just need to release the vnode mutex. Mark as
* as VI_DOINGINACT to avoid recursion.
*/
vp->v_iflag |= VI_DOINGINACT;
VI_UNLOCK(vp);
VOP_INACTIVE(vp, td);
VI_LOCK(vp);
KASSERT(vp->v_iflag & VI_DOINGINACT,
("vput: lost VI_DOINGINACT"));
vp->v_iflag &= ~VI_DOINGINACT;
if (VSHOULDFREE(vp))
vfree(vp);
else
vlruvp(vp);
VI_UNLOCK(vp);
} else {
#ifdef DIAGNOSTIC
vprint("vput: negative ref count", vp);
#endif
panic("vput: negative ref cnt");
}
}
/*
* Somebody doesn't want the vnode recycled.
*/
void
vhold(struct vnode *vp)
{
VI_LOCK(vp);
vholdl(vp);
VI_UNLOCK(vp);
}
void
vholdl(struct vnode *vp)
{
vp->v_holdcnt++;
if (VSHOULDBUSY(vp))
vbusy(vp);
}
/*
* Note that there is one less who cares about this vnode. vdrop() is the
* opposite of vhold().
*/
void
vdrop(struct vnode *vp)
{
VI_LOCK(vp);
vdropl(vp);
VI_UNLOCK(vp);
}
void
vdropl(vp)
register struct vnode *vp;
{
if (vp->v_holdcnt <= 0)
panic("vdrop: holdcnt");
vp->v_holdcnt--;
if (VSHOULDFREE(vp))
vfree(vp);
else
vlruvp(vp);
}
/*
* 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 VV_SYSTEM to be skipped.
*
* `rootrefs' specifies the base reference count for the root vnode
* of this filesystem. The root vnode is considered busy if its
* v_usecount exceeds this value. On a successful return, vflush(, td)
* will call vrele() on the root vnode exactly rootrefs times.
* If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must
* be zero.
*/
#ifdef DIAGNOSTIC
static int busyprt = 0; /* print out busy vnodes */
SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "");
#endif
int
vflush(mp, rootrefs, flags, td)
struct mount *mp;
int rootrefs;
int flags;
struct thread *td;
{
struct vnode *vp, *nvp, *rootvp = NULL;
struct vattr vattr;
int busy = 0, error;
if (rootrefs > 0) {
KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0,
("vflush: bad args"));
/*
* Get the filesystem root vnode. We can vput() it
* immediately, since with rootrefs > 0, it won't go away.
*/
if ((error = VFS_ROOT(mp, &rootvp, td)) != 0)
return (error);
vput(rootvp);
}
MNT_ILOCK(mp);
loop:
MNT_VNODE_FOREACH(vp, mp, nvp) {
VI_LOCK(vp);
MNT_IUNLOCK(mp);
error = vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE, td);
if (error) {
MNT_ILOCK(mp);
goto loop;
}
/*
* Skip over a vnodes marked VV_SYSTEM.
*/
if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) {
VOP_UNLOCK(vp, 0, td);
MNT_ILOCK(mp);
continue;
}
/*
* If WRITECLOSE is set, flush out unlinked but still open
* files (even if open only for reading) and regular file
* vnodes open for writing.
*/
if (flags & WRITECLOSE) {
error = VOP_GETATTR(vp, &vattr, td->td_ucred, td);
VI_LOCK(vp);
if ((vp->v_type == VNON ||
(error == 0 && vattr.va_nlink > 0)) &&
(vp->v_writecount == 0 || vp->v_type != VREG)) {
VOP_UNLOCK(vp, LK_INTERLOCK, td);
MNT_ILOCK(mp);
continue;
}
} else
VI_LOCK(vp);
VOP_UNLOCK(vp, 0, td);
/*
* 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, td);
MNT_ILOCK(mp);
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 != VCHR)
vgonel(vp, td);
else
vgonechrl(vp, td);
MNT_ILOCK(mp);
continue;
}
#ifdef DIAGNOSTIC
if (busyprt)
vprint("vflush: busy vnode", vp);
#endif
VI_UNLOCK(vp);
MNT_ILOCK(mp);
busy++;
}
MNT_IUNLOCK(mp);
if (rootrefs > 0 && (flags & FORCECLOSE) == 0) {
/*
* If just the root vnode is busy, and if its refcount
* is equal to `rootrefs', then go ahead and kill it.
*/
VI_LOCK(rootvp);
KASSERT(busy > 0, ("vflush: not busy"));
KASSERT(rootvp->v_usecount >= rootrefs,
("vflush: usecount %d < rootrefs %d",
rootvp->v_usecount, rootrefs));
if (busy == 1 && rootvp->v_usecount == rootrefs) {
vgonel(rootvp, td);
busy = 0;
} else
VI_UNLOCK(rootvp);
}
if (busy)
return (EBUSY);
for (; rootrefs > 0; rootrefs--)
vrele(rootvp);
return (0);
}
/*
* This moves a now (likely recyclable) vnode to the end of the
* mountlist. XXX However, it is temporarily disabled until we
* can clean up ffs_sync() and friends, which have loop restart
* conditions which this code causes to operate O(N^2).
*/
static void
vlruvp(struct vnode *vp)
{
#if 0
struct mount *mp;
if ((mp = vp->v_mount) != NULL) {
MNT_ILOCK(mp);
TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
MNT_IUNLOCK(mp);
}
#endif
}
static void
vx_lock(struct vnode *vp)
{
ASSERT_VI_LOCKED(vp, "vx_lock");
/*
* Prevent the vnode from being recycled or brought into use while we
* clean it out.
*/
if (vp->v_iflag & VI_XLOCK)
panic("vclean: deadlock");
vp->v_iflag |= VI_XLOCK;
vp->v_vxthread = curthread;
}
static void
vx_unlock(struct vnode *vp)
{
ASSERT_VI_LOCKED(vp, "vx_unlock");
vp->v_iflag &= ~VI_XLOCK;
vp->v_vxthread = NULL;
if (vp->v_iflag & VI_XWANT) {
vp->v_iflag &= ~VI_XWANT;
wakeup(vp);
}
}
/*
* Disassociate the underlying filesystem from a vnode.
*/
static void
vclean(vp, flags, td)
struct vnode *vp;
int flags;
struct thread *td;
{
int active;
ASSERT_VI_LOCKED(vp, "vclean");
/*
* 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))
v_incr_usecount(vp, 1);
/*
* 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, LK_DRAIN | LK_INTERLOCK, td);
/*
* Clean out any buffers associated with the vnode.
* If the flush fails, just toss the buffers.
*/
if (flags & DOCLOSE) {
struct buf *bp;
bp = TAILQ_FIRST(&vp->v_bufobj.bo_dirty.bv_hd);
if (bp != NULL)
(void) vn_write_suspend_wait(vp, NULL, V_WAIT);
if (vinvalbuf(vp, V_SAVE, NOCRED, td, 0, 0) != 0)
vinvalbuf(vp, 0, NOCRED, td, 0, 0);
}
VOP_DESTROYVOBJECT(vp);
/*
* Any other processes trying to obtain this lock must first
* wait for VXLOCK to clear, then call the new lock operation.
*/
VOP_UNLOCK(vp, 0, td);
/*
* If purging an active vnode, it must be closed and
* deactivated before being reclaimed. Note that the
* VOP_INACTIVE will unlock the vnode.
*/
if (active) {
if (flags & DOCLOSE)
VOP_CLOSE(vp, FNONBLOCK, NOCRED, td);
VI_LOCK(vp);
if ((vp->v_iflag & VI_DOINGINACT) == 0) {
vp->v_iflag |= VI_DOINGINACT;
VI_UNLOCK(vp);
if (vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT, td) != 0)
panic("vclean: cannot relock.");
VOP_INACTIVE(vp, td);
VI_LOCK(vp);
KASSERT(vp->v_iflag & VI_DOINGINACT,
("vclean: lost VI_DOINGINACT"));
vp->v_iflag &= ~VI_DOINGINACT;
}
VI_UNLOCK(vp);
}
/*
* Reclaim the vnode.
*/
if (VOP_RECLAIM(vp, td))
panic("vclean: cannot reclaim");
if (active) {
/*
* Inline copy of vrele() since VOP_INACTIVE
* has already been called.
*/
VI_LOCK(vp);
v_incr_usecount(vp, -1);
if (vp->v_usecount <= 0) {
#ifdef INVARIANTS
if (vp->v_usecount < 0 || vp->v_writecount != 0) {
vprint("vclean: bad ref count", vp);
panic("vclean: ref cnt");
}
#endif
if (VSHOULDFREE(vp))
vfree(vp);
}
VI_UNLOCK(vp);
}
/*
* Delete from old mount point vnode list.
*/
delmntque(vp);
cache_purge(vp);
VI_LOCK(vp);
if (VSHOULDFREE(vp))
vfree(vp);
/*
* Done with purge, reset to the standard lock and
* notify sleepers of the grim news.
*/
vp->v_vnlock = &vp->v_lock;
vp->v_op = dead_vnodeop_p;
if (vp->v_pollinfo != NULL)
vn_pollgone(vp);
vp->v_tag = "none";
}
/*
* Eliminate all activity associated with the requested vnode
* and with all vnodes aliased to the requested vnode.
*/
int
vop_revoke(ap)
struct vop_revoke_args /* {
struct vnode *a_vp;
int a_flags;
} */ *ap;
{
struct vnode *vp, *vq;
struct cdev *dev;
KASSERT((ap->a_flags & REVOKEALL) != 0, ("vop_revoke"));
vp = ap->a_vp;
KASSERT((vp->v_type == VCHR), ("vop_revoke: not VCHR"));
VI_LOCK(vp);
/*
* If a vgone (or vclean) is already in progress,
* wait until it is done and return.
*/
if (vp->v_iflag & VI_XLOCK) {
vp->v_iflag |= VI_XWANT;
msleep(vp, VI_MTX(vp), PINOD | PDROP,
"vop_revokeall", 0);
return (0);
}
VI_UNLOCK(vp);
dev = vp->v_rdev;
for (;;) {
dev_lock();
vq = SLIST_FIRST(&dev->si_hlist);
dev_unlock();
if (vq == NULL)
break;
vgone(vq);
}
return (0);
}
/*
* Recycle an unused vnode to the front of the free list.
* Release the passed interlock if the vnode will be recycled.
*/
int
vrecycle(vp, inter_lkp, td)
struct vnode *vp;
struct mtx *inter_lkp;
struct thread *td;
{
VI_LOCK(vp);
if (vp->v_usecount == 0) {
if (inter_lkp) {
mtx_unlock(inter_lkp);
}
vgonel(vp, td);
return (1);
}
VI_UNLOCK(vp);
return (0);
}
/*
* Eliminate all activity associated with a vnode
* in preparation for reuse.
*/
void
vgone(vp)
register struct vnode *vp;
{
struct thread *td = curthread; /* XXX */
VI_LOCK(vp);
vgonel(vp, td);
}
/*
* Disassociate a character device from the its underlying filesystem and
* attach it to spec. This is for use when the chr device is still active
* and the filesystem is going away.
*/
static void
vgonechrl(struct vnode *vp, struct thread *td)
{
ASSERT_VI_LOCKED(vp, "vgonechrl");
vx_lock(vp);
/*
* This is a custom version of vclean() which does not tearm down
* the bufs or vm objects held by this vnode. This allows filesystems
* to continue using devices which were discovered via another
* filesystem that has been unmounted.
*/
if (vp->v_usecount != 0) {
v_incr_usecount(vp, 1);
/*
* Ensure that no other activity can occur while the
* underlying object is being cleaned out.
*/
VOP_LOCK(vp, LK_DRAIN | LK_INTERLOCK, td);
/*
* Any other processes trying to obtain this lock must first
* wait for VXLOCK to clear, then call the new lock operation.
*/
VOP_UNLOCK(vp, 0, td);
vp->v_vnlock = &vp->v_lock;
vp->v_tag = "orphanchr";
vp->v_op = devfs_specop_p;
delmntque(vp);
cache_purge(vp);
vrele(vp);
VI_LOCK(vp);
} else
vclean(vp, 0, td);
vp->v_op = devfs_specop_p;
vx_unlock(vp);
VI_UNLOCK(vp);
}
/*
* vgone, with the vp interlock held.
*/
void
vgonel(vp, td)
struct vnode *vp;
struct thread *td;
{
/*
* If a vgone (or vclean) is already in progress,
* wait until it is done and return.
*/
ASSERT_VI_LOCKED(vp, "vgonel");
if (vp->v_iflag & VI_XLOCK) {
vp->v_iflag |= VI_XWANT;
msleep(vp, VI_MTX(vp), PINOD | PDROP, "vgone", 0);
return;
}
vx_lock(vp);
/*
* Clean out the filesystem specific data.
*/
vclean(vp, DOCLOSE, td);
VI_UNLOCK(vp);
/*
* If special device, remove it from special device alias list
* if it is on one.
*/
VI_LOCK(vp);
if (vp->v_type == VCHR && vp->v_rdev != NULL)
dev_rel(vp);
/*
* If it is on the freelist and not already at the head,
* move it to the head of the list. The test of the
* VDOOMED flag 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.
*/
if (vp->v_usecount == 0 && !(vp->v_iflag & VI_DOOMED)) {
mtx_lock(&vnode_free_list_mtx);
if (vp->v_iflag & VI_FREE) {
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
} else {
vp->v_iflag |= VI_FREE;
freevnodes++;
}
TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
mtx_unlock(&vnode_free_list_mtx);
}
vp->v_type = VBAD;
vx_unlock(vp);
VI_UNLOCK(vp);
}
/*
* Lookup a vnode by device number.
*/
int
vfinddev(dev, vpp)
struct cdev *dev;
struct vnode **vpp;
{
struct vnode *vp;
dev_lock();
SLIST_FOREACH(vp, &dev->si_hlist, v_specnext) {
*vpp = vp;
dev_unlock();
return (1);
}
dev_unlock();
return (0);
}
/*
* Calculate the total number of references to a special device.
*/
int
vcount(vp)
struct vnode *vp;
{
int count;
dev_lock();
count = vp->v_rdev->si_usecount;
dev_unlock();
return (count);
}
/*
* Same as above, but using the struct cdev *as argument
*/
int
count_dev(dev)
struct cdev *dev;
{
int count;
dev_lock();
count = dev->si_usecount;
dev_unlock();
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;
struct vnode *vp;
{
char buf[96];
if (label != NULL)
printf("%s: %p: ", label, (void *)vp);
else
printf("%p: ", (void *)vp);
printf("tag %s, type %s, usecount %d, writecount %d, refcount %d,",
vp->v_tag, typename[vp->v_type], vp->v_usecount,
vp->v_writecount, vp->v_holdcnt);
buf[0] = '\0';
if (vp->v_vflag & VV_ROOT)
strcat(buf, "|VV_ROOT");
if (vp->v_vflag & VV_TEXT)
strcat(buf, "|VV_TEXT");
if (vp->v_vflag & VV_SYSTEM)
strcat(buf, "|VV_SYSTEM");
if (vp->v_iflag & VI_XLOCK)
strcat(buf, "|VI_XLOCK");
if (vp->v_iflag & VI_XWANT)
strcat(buf, "|VI_XWANT");
if (vp->v_iflag & VI_DOOMED)
strcat(buf, "|VI_DOOMED");
if (vp->v_iflag & VI_FREE)
strcat(buf, "|VI_FREE");
if (vp->v_vflag & VV_OBJBUF)
strcat(buf, "|VV_OBJBUF");
if (buf[0] != '\0')
printf(" flags (%s),", &buf[1]);
lockmgr_printinfo(vp->v_vnlock);
printf("\n");
if (vp->v_data != NULL)
VOP_PRINT(vp);
}
#ifdef DDB
#include <ddb/ddb.h>
/*
* List all of the locked vnodes in the system.
* Called when debugging the kernel.
*/
DB_SHOW_COMMAND(lockedvnods, lockedvnodes)
{
struct mount *mp, *nmp;
struct vnode *vp;
/*
* Note: because this is DDB, we can't obey the locking semantics
* for these structures, which means we could catch an inconsistent
* state and dereference a nasty pointer. Not much to be done
* about that.
*/
printf("Locked vnodes\n");
for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
nmp = TAILQ_NEXT(mp, mnt_list);
TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
if (VOP_ISLOCKED(vp, NULL))
vprint(NULL, vp);
}
nmp = TAILQ_NEXT(mp, mnt_list);
}
}
#endif
/*
* Fill in a struct xvfsconf based on a struct vfsconf.
*/
static void
vfsconf2x(struct vfsconf *vfsp, struct xvfsconf *xvfsp)
{
strcpy(xvfsp->vfc_name, vfsp->vfc_name);
xvfsp->vfc_typenum = vfsp->vfc_typenum;
xvfsp->vfc_refcount = vfsp->vfc_refcount;
xvfsp->vfc_flags = vfsp->vfc_flags;
/*
* These are unused in userland, we keep them
* to not break binary compatibility.
*/
xvfsp->vfc_vfsops = NULL;
xvfsp->vfc_next = NULL;
}
/*
* Top level filesystem related information gathering.
*/
static int
sysctl_vfs_conflist(SYSCTL_HANDLER_ARGS)
{
struct vfsconf *vfsp;
struct xvfsconf xvfsp;
int error;
error = 0;
TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
vfsconf2x(vfsp, &xvfsp);
error = SYSCTL_OUT(req, &xvfsp, sizeof xvfsp);
if (error)
break;
}
return (error);
}
SYSCTL_PROC(_vfs, OID_AUTO, conflist, CTLFLAG_RD, NULL, 0, sysctl_vfs_conflist,
"S,xvfsconf", "List of all configured filesystems");
#ifndef BURN_BRIDGES
static int sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS);
static int
vfs_sysctl(SYSCTL_HANDLER_ARGS)
{
int *name = (int *)arg1 - 1; /* XXX */
u_int namelen = arg2 + 1; /* XXX */
struct vfsconf *vfsp;
struct xvfsconf xvfsp;
printf("WARNING: userland calling deprecated sysctl, "
"please rebuild world\n");
#if 1 || defined(COMPAT_PRELITE2)
/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
if (namelen == 1)
return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
#endif
switch (name[1]) {
case VFS_MAXTYPENUM:
if (namelen != 2)
return (ENOTDIR);
return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
case VFS_CONF:
if (namelen != 3)
return (ENOTDIR); /* overloaded */
TAILQ_FOREACH(vfsp, &vfsconf, vfc_list)
if (vfsp->vfc_typenum == name[2])
break;
if (vfsp == NULL)
return (EOPNOTSUPP);
vfsconf2x(vfsp, &xvfsp);
return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
}
return (EOPNOTSUPP);
}
SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD | CTLFLAG_SKIP, vfs_sysctl,
"Generic filesystem");
#if 1 || defined(COMPAT_PRELITE2)
static int
sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
{
int error;
struct vfsconf *vfsp;
struct ovfsconf ovfs;
TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
ovfs.vfc_vfsops = vfsp->vfc_vfsops; /* XXX used as flag */
strcpy(ovfs.vfc_name, vfsp->vfc_name);
ovfs.vfc_index = vfsp->vfc_typenum;
ovfs.vfc_refcount = vfsp->vfc_refcount;
ovfs.vfc_flags = vfsp->vfc_flags;
error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
if (error)
return error;
}
return 0;
}
#endif /* 1 || COMPAT_PRELITE2 */
#endif /* !BURN_BRIDGES */
#define KINFO_VNODESLOP 10
#ifdef notyet
/*
* Dump vnode list (via sysctl).
*/
/* ARGSUSED */
static int
sysctl_vnode(SYSCTL_HANDLER_ARGS)
{
struct xvnode *xvn;
struct thread *td = req->td;
struct mount *mp;
struct vnode *vp;
int error, len, n;
/*
* Stale numvnodes access is not fatal here.
*/
req->lock = 0;
len = (numvnodes + KINFO_VNODESLOP) * sizeof *xvn;
if (!req->oldptr)
/* Make an estimate */
return (SYSCTL_OUT(req, 0, len));
error = sysctl_wire_old_buffer(req, 0);
if (error != 0)
return (error);
xvn = malloc(len, M_TEMP, M_ZERO | M_WAITOK);
n = 0;
mtx_lock(&mountlist_mtx);
TAILQ_FOREACH(mp, &mountlist, mnt_list) {
if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td))
continue;
MNT_ILOCK(mp);
TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
if (n == len)
break;
vref(vp);
xvn[n].xv_size = sizeof *xvn;
xvn[n].xv_vnode = vp;
#define XV_COPY(field) xvn[n].xv_##field = vp->v_##field
XV_COPY(usecount);
XV_COPY(writecount);
XV_COPY(holdcnt);
XV_COPY(id);
XV_COPY(mount);
XV_COPY(numoutput);
XV_COPY(type);
#undef XV_COPY
xvn[n].xv_flag = vp->v_vflag;
switch (vp->v_type) {
case VREG:
case VDIR:
case VLNK:
xvn[n].xv_dev = vp->v_cachedfs;
xvn[n].xv_ino = vp->v_cachedid;
break;
case VBLK:
case VCHR:
if (vp->v_rdev == NULL) {
vrele(vp);
continue;
}
xvn[n].xv_dev = dev2udev(vp->v_rdev);
break;
case VSOCK:
xvn[n].xv_socket = vp->v_socket;
break;
case VFIFO:
xvn[n].xv_fifo = vp->v_fifoinfo;
break;
case VNON:
case VBAD:
default:
/* shouldn't happen? */
vrele(vp);
continue;
}
vrele(vp);
++n;
}
MNT_IUNLOCK(mp);
mtx_lock(&mountlist_mtx);
vfs_unbusy(mp, td);
if (n == len)
break;
}
mtx_unlock(&mountlist_mtx);
error = SYSCTL_OUT(req, xvn, n * sizeof *xvn);
free(xvn, M_TEMP);
return (error);
}
SYSCTL_PROC(_kern, KERN_VNODE, vnode, CTLTYPE_OPAQUE|CTLFLAG_RD,
0, 0, sysctl_vnode, "S,xvnode", "");
#endif
/*
* Check to see if a filesystem is mounted on a block device.
*/
int
vfs_mountedon(vp)
struct vnode *vp;
{
if (vp->v_rdev->si_mountpoint != NULL)
return (EBUSY);
return (0);
}
/*
* Unmount all filesystems. The list is traversed in reverse order
* of mounting to avoid dependencies.
*/
void
vfs_unmountall()
{
struct mount *mp;
struct thread *td;
int error;
if (curthread != NULL)
td = curthread;
else
td = FIRST_THREAD_IN_PROC(initproc); /* XXX XXX proc0? */
/*
* Since this only runs when rebooting, it is not interlocked.
*/
while(!TAILQ_EMPTY(&mountlist)) {
mp = TAILQ_LAST(&mountlist, mntlist);
error = dounmount(mp, MNT_FORCE, td);
if (error) {
TAILQ_REMOVE(&mountlist, mp, mnt_list);
printf("unmount of %s failed (",
mp->mnt_stat.f_mntonname);
if (error == EBUSY)
printf("BUSY)\n");
else
printf("%d)\n", error);
} else {
/* The unmount has removed mp from the mountlist */
}
}
}
/*
* 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, *nvp;
struct vm_object *obj;
int tries;
GIANT_REQUIRED;
tries = 5;
MNT_ILOCK(mp);
loop:
TAILQ_FOREACH_SAFE(vp, &mp->mnt_nvnodelist, v_nmntvnodes, nvp) {
if (vp->v_mount != mp) {
if (--tries > 0)
goto loop;
break;
}
VI_LOCK(vp);
if (vp->v_iflag & VI_XLOCK) {
VI_UNLOCK(vp);
continue;
}
if ((vp->v_iflag & VI_OBJDIRTY) &&
(flags == MNT_WAIT || VOP_ISLOCKED(vp, NULL) == 0)) {
MNT_IUNLOCK(mp);
if (!vget(vp,
LK_EXCLUSIVE | LK_RETRY | LK_INTERLOCK,
curthread)) {
if (vp->v_vflag & VV_NOSYNC) { /* unlinked */
vput(vp);
MNT_ILOCK(mp);
continue;
}
if (VOP_GETVOBJECT(vp, &obj) == 0) {
VM_OBJECT_LOCK(obj);
vm_object_page_clean(obj, 0, 0,
flags == MNT_WAIT ?
OBJPC_SYNC : OBJPC_NOSYNC);
VM_OBJECT_UNLOCK(obj);
}
vput(vp);
}
MNT_ILOCK(mp);
if (TAILQ_NEXT(vp, v_nmntvnodes) != nvp) {
if (--tries > 0)
goto loop;
break;
}
} else
VI_UNLOCK(vp);
}
MNT_IUNLOCK(mp);
}
/*
* Create the VM object needed for VMIO and mmap support. This
* is done for all VREG files in the system. Some filesystems might
* afford the additional metadata buffering capability of the
* VMIO code by making the device node be VMIO mode also.
*
* vp must be locked when vfs_object_create is called.
*/
int
vfs_object_create(struct vnode *vp, struct thread *td, struct ucred *cred)
{
GIANT_REQUIRED;
return (VOP_CREATEVOBJECT(vp, cred, td));
}
/*
* Mark a vnode as free, putting it up for recycling.
*/
void
vfree(struct vnode *vp)
{
ASSERT_VI_LOCKED(vp, "vfree");
mtx_lock(&vnode_free_list_mtx);
KASSERT((vp->v_iflag & VI_FREE) == 0, ("vnode already free"));
if (vp->v_iflag & VI_AGE) {
TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
} else {
TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
}
freevnodes++;
mtx_unlock(&vnode_free_list_mtx);
vp->v_iflag &= ~VI_AGE;
vp->v_iflag |= VI_FREE;
}
/*
* Opposite of vfree() - mark a vnode as in use.
*/
void
vbusy(struct vnode *vp)
{
ASSERT_VI_LOCKED(vp, "vbusy");
KASSERT((vp->v_iflag & VI_FREE) != 0, ("vnode not free"));
mtx_lock(&vnode_free_list_mtx);
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
freevnodes--;
mtx_unlock(&vnode_free_list_mtx);
vp->v_iflag &= ~(VI_FREE|VI_AGE);
}
/*
* Initalize per-vnode helper structure to hold poll-related state.
*/
void
v_addpollinfo(struct vnode *vp)
{
struct vpollinfo *vi;
vi = uma_zalloc(vnodepoll_zone, M_WAITOK);
if (vp->v_pollinfo != NULL) {
uma_zfree(vnodepoll_zone, vi);
return;
}
vp->v_pollinfo = vi;
mtx_init(&vp->v_pollinfo->vpi_lock, "vnode pollinfo", NULL, MTX_DEF);
knlist_init(&vp->v_pollinfo->vpi_selinfo.si_note,
&vp->v_pollinfo->vpi_lock);
}
/*
* Record a process's interest in events which might happen to
* a vnode. Because poll uses the historic select-style interface
* internally, this routine serves as both the ``check for any
* pending events'' and the ``record my interest in future events''
* functions. (These are done together, while the lock is held,
* to avoid race conditions.)
*/
int
vn_pollrecord(vp, td, events)
struct vnode *vp;
struct thread *td;
short events;
{
if (vp->v_pollinfo == NULL)
v_addpollinfo(vp);
mtx_lock(&vp->v_pollinfo->vpi_lock);
if (vp->v_pollinfo->vpi_revents & events) {
/*
* This leaves events we are not interested
* in available for the other process which
* which presumably had requested them
* (otherwise they would never have been
* recorded).
*/
events &= vp->v_pollinfo->vpi_revents;
vp->v_pollinfo->vpi_revents &= ~events;
mtx_unlock(&vp->v_pollinfo->vpi_lock);
return events;
}
vp->v_pollinfo->vpi_events |= events;
selrecord(td, &vp->v_pollinfo->vpi_selinfo);
mtx_unlock(&vp->v_pollinfo->vpi_lock);
return 0;
}
/*
* Note the occurrence of an event. If the VN_POLLEVENT macro is used,
* it is possible for us to miss an event due to race conditions, but
* that condition is expected to be rare, so for the moment it is the
* preferred interface.
*/
void
vn_pollevent(vp, events)
struct vnode *vp;
short events;
{
if (vp->v_pollinfo == NULL)
v_addpollinfo(vp);
mtx_lock(&vp->v_pollinfo->vpi_lock);
if (vp->v_pollinfo->vpi_events & events) {
/*
* We clear vpi_events so that we don't
* call selwakeup() twice if two events are
* posted before the polling process(es) is
* awakened. This also ensures that we take at
* most one selwakeup() if the polling process
* is no longer interested. However, it does
* mean that only one event can be noticed at
* a time. (Perhaps we should only clear those
* event bits which we note?) XXX
*/
vp->v_pollinfo->vpi_events = 0; /* &= ~events ??? */
vp->v_pollinfo->vpi_revents |= events;
selwakeuppri(&vp->v_pollinfo->vpi_selinfo, PRIBIO);
}
mtx_unlock(&vp->v_pollinfo->vpi_lock);
}
/*
* Wake up anyone polling on vp because it is being revoked.
* This depends on dead_poll() returning POLLHUP for correct
* behavior.
*/
void
vn_pollgone(vp)
struct vnode *vp;
{
mtx_lock(&vp->v_pollinfo->vpi_lock);
VN_KNOTE_LOCKED(vp, NOTE_REVOKE);
if (vp->v_pollinfo->vpi_events) {
vp->v_pollinfo->vpi_events = 0;
selwakeuppri(&vp->v_pollinfo->vpi_selinfo, PRIBIO);
}
mtx_unlock(&vp->v_pollinfo->vpi_lock);
}
/*
* Routine to create and manage a filesystem syncer vnode.
*/
#define sync_close ((int (*)(struct vop_close_args *))nullop)
static int sync_fsync(struct vop_fsync_args *);
static int sync_inactive(struct vop_inactive_args *);
static int sync_reclaim(struct vop_reclaim_args *);
static vop_t **sync_vnodeop_p;
static struct vnodeopv_entry_desc sync_vnodeop_entries[] = {
{ &vop_default_desc, (vop_t *) vop_eopnotsupp },
{ &vop_close_desc, (vop_t *) sync_close }, /* close */
{ &vop_fsync_desc, (vop_t *) sync_fsync }, /* fsync */
{ &vop_inactive_desc, (vop_t *) sync_inactive }, /* inactive */
{ &vop_reclaim_desc, (vop_t *) sync_reclaim }, /* reclaim */
{ &vop_lock_desc, (vop_t *) vop_stdlock }, /* lock */
{ &vop_unlock_desc, (vop_t *) vop_stdunlock }, /* unlock */
{ &vop_islocked_desc, (vop_t *) vop_stdislocked }, /* islocked */
{ NULL, NULL }
};
static struct vnodeopv_desc sync_vnodeop_opv_desc =
{ &sync_vnodeop_p, sync_vnodeop_entries };
VNODEOP_SET(sync_vnodeop_opv_desc);
/*
* Create a new filesystem syncer vnode for the specified mount point.
*/
int
vfs_allocate_syncvnode(mp)
struct mount *mp;
{
struct vnode *vp;
static long start, incr, next;
int error;
/* Allocate a new vnode */
if ((error = getnewvnode("syncer", mp, sync_vnodeop_p, &vp)) != 0) {
mp->mnt_syncer = NULL;
return (error);
}
vp->v_type = VNON;
/*
* Place the vnode onto the syncer worklist. We attempt to
* scatter them about on the list so that they will go off
* at evenly distributed times even if all the filesystems
* are mounted at once.
*/
next += incr;
if (next == 0 || next > syncer_maxdelay) {
start /= 2;
incr /= 2;
if (start == 0) {
start = syncer_maxdelay / 2;
incr = syncer_maxdelay;
}
next = start;
}
VI_LOCK(vp);
vn_syncer_add_to_worklist(vp, syncdelay > 0 ? next % syncdelay : 0);
/* XXX - vn_syncer_add_to_worklist() also grabs and drops sync_mtx. */
mtx_lock(&sync_mtx);
sync_vnode_count++;
mtx_unlock(&sync_mtx);
VI_UNLOCK(vp);
mp->mnt_syncer = vp;
return (0);
}
/*
* Do a lazy sync of the filesystem.
*/
static int
sync_fsync(ap)
struct vop_fsync_args /* {
struct vnode *a_vp;
struct ucred *a_cred;
int a_waitfor;
struct thread *a_td;
} */ *ap;
{
struct vnode *syncvp = ap->a_vp;
struct mount *mp = syncvp->v_mount;
struct thread *td = ap->a_td;
int error, asyncflag;
/*
* We only need to do something if this is a lazy evaluation.
*/
if (ap->a_waitfor != MNT_LAZY)
return (0);
/*
* Move ourselves to the back of the sync list.
*/
VI_LOCK(syncvp);
vn_syncer_add_to_worklist(syncvp, syncdelay);
VI_UNLOCK(syncvp);
/*
* Walk the list of vnodes pushing all that are dirty and
* not already on the sync list.
*/
mtx_lock(&mountlist_mtx);
if (vfs_busy(mp, LK_EXCLUSIVE | LK_NOWAIT, &mountlist_mtx, td) != 0) {
mtx_unlock(&mountlist_mtx);
return (0);
}
if (vn_start_write(NULL, &mp, V_NOWAIT) != 0) {
vfs_unbusy(mp, td);
return (0);
}
asyncflag = mp->mnt_flag & MNT_ASYNC;
mp->mnt_flag &= ~MNT_ASYNC;
vfs_msync(mp, MNT_NOWAIT);
error = VFS_SYNC(mp, MNT_LAZY, ap->a_cred, td);
if (asyncflag)
mp->mnt_flag |= MNT_ASYNC;
vn_finished_write(mp);
vfs_unbusy(mp, td);
return (error);
}
/*
* The syncer vnode is no referenced.
*/
static int
sync_inactive(ap)
struct vop_inactive_args /* {
struct vnode *a_vp;
struct thread *a_td;
} */ *ap;
{
VOP_UNLOCK(ap->a_vp, 0, ap->a_td);
vgone(ap->a_vp);
return (0);
}
/*
* The syncer vnode is no longer needed and is being decommissioned.
*
* Modifications to the worklist must be protected by sync_mtx.
*/
static int
sync_reclaim(ap)
struct vop_reclaim_args /* {
struct vnode *a_vp;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
VI_LOCK(vp);
vp->v_mount->mnt_syncer = NULL;
if (vp->v_iflag & VI_ONWORKLST) {
mtx_lock(&sync_mtx);
LIST_REMOVE(vp, v_synclist);
syncer_worklist_len--;
sync_vnode_count--;
mtx_unlock(&sync_mtx);
vp->v_iflag &= ~VI_ONWORKLST;
}
VI_UNLOCK(vp);
return (0);
}
/*
* extract the struct cdev *from a VCHR
*/
struct cdev *
vn_todev(vp)
struct vnode *vp;
{
if (vp->v_type != VCHR)
return (NULL);
return (vp->v_rdev);
}
/*
* Check if vnode represents a disk device
*/
int
vn_isdisk(vp, errp)
struct vnode *vp;
int *errp;
{
int error;
error = 0;
dev_lock();
if (vp->v_type != VCHR)
error = ENOTBLK;
else if (vp->v_rdev == NULL)
error = ENXIO;
else if (vp->v_rdev->si_devsw == NULL)
error = ENXIO;
else if (!(vp->v_rdev->si_devsw->d_flags & D_DISK))
error = ENOTBLK;
dev_unlock();
if (errp != NULL)
*errp = error;
return (error == 0);
}
/*
* Free data allocated by namei(); see namei(9) for details.
*/
void
NDFREE(ndp, flags)
struct nameidata *ndp;
const u_int flags;
{
if (!(flags & NDF_NO_FREE_PNBUF) &&
(ndp->ni_cnd.cn_flags & HASBUF)) {
uma_zfree(namei_zone, ndp->ni_cnd.cn_pnbuf);
ndp->ni_cnd.cn_flags &= ~HASBUF;
}
if (!(flags & NDF_NO_DVP_UNLOCK) &&
(ndp->ni_cnd.cn_flags & LOCKPARENT) &&
ndp->ni_dvp != ndp->ni_vp)
VOP_UNLOCK(ndp->ni_dvp, 0, ndp->ni_cnd.cn_thread);
if (!(flags & NDF_NO_DVP_RELE) &&
(ndp->ni_cnd.cn_flags & (LOCKPARENT|WANTPARENT))) {
vrele(ndp->ni_dvp);
ndp->ni_dvp = NULL;
}
if (!(flags & NDF_NO_VP_UNLOCK) &&
(ndp->ni_cnd.cn_flags & LOCKLEAF) && ndp->ni_vp)
VOP_UNLOCK(ndp->ni_vp, 0, ndp->ni_cnd.cn_thread);
if (!(flags & NDF_NO_VP_RELE) &&
ndp->ni_vp) {
vrele(ndp->ni_vp);
ndp->ni_vp = NULL;
}
if (!(flags & NDF_NO_STARTDIR_RELE) &&
(ndp->ni_cnd.cn_flags & SAVESTART)) {
vrele(ndp->ni_startdir);
ndp->ni_startdir = NULL;
}
}
/*
* Common filesystem object access control check routine. Accepts a
* vnode's type, "mode", uid and gid, requested access mode, credentials,
* and optional call-by-reference privused argument allowing vaccess()
* to indicate to the caller whether privilege was used to satisfy the
* request (obsoleted). Returns 0 on success, or an errno on failure.
*/
int
vaccess(type, file_mode, file_uid, file_gid, acc_mode, cred, privused)
enum vtype type;
mode_t file_mode;
uid_t file_uid;
gid_t file_gid;
mode_t acc_mode;
struct ucred *cred;
int *privused;
{
mode_t dac_granted;
#ifdef CAPABILITIES
mode_t cap_granted;
#endif
/*
* Look for a normal, non-privileged way to access the file/directory
* as requested. If it exists, go with that.
*/
if (privused != NULL)
*privused = 0;
dac_granted = 0;
/* Check the owner. */
if (cred->cr_uid == file_uid) {
dac_granted |= VADMIN;
if (file_mode & S_IXUSR)
dac_granted |= VEXEC;
if (file_mode & S_IRUSR)
dac_granted |= VREAD;
if (file_mode & S_IWUSR)
dac_granted |= (VWRITE | VAPPEND);
if ((acc_mode & dac_granted) == acc_mode)
return (0);
goto privcheck;
}
/* Otherwise, check the groups (first match) */
if (groupmember(file_gid, cred)) {
if (file_mode & S_IXGRP)
dac_granted |= VEXEC;
if (file_mode & S_IRGRP)
dac_granted |= VREAD;
if (file_mode & S_IWGRP)
dac_granted |= (VWRITE | VAPPEND);
if ((acc_mode & dac_granted) == acc_mode)
return (0);
goto privcheck;
}
/* Otherwise, check everyone else. */
if (file_mode & S_IXOTH)
dac_granted |= VEXEC;
if (file_mode & S_IROTH)
dac_granted |= VREAD;
if (file_mode & S_IWOTH)
dac_granted |= (VWRITE | VAPPEND);
if ((acc_mode & dac_granted) == acc_mode)
return (0);
privcheck:
if (!suser_cred(cred, SUSER_ALLOWJAIL)) {
/* XXX audit: privilege used */
if (privused != NULL)
*privused = 1;
return (0);
}
#ifdef CAPABILITIES
/*
* Build a capability mask to determine if the set of capabilities
* satisfies the requirements when combined with the granted mask
* from above.
* For each capability, if the capability is required, bitwise
* or the request type onto the cap_granted mask.
*/
cap_granted = 0;
if (type == VDIR) {
/*
* For directories, use CAP_DAC_READ_SEARCH to satisfy
* VEXEC requests, instead of CAP_DAC_EXECUTE.
*/
if ((acc_mode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
!cap_check(cred, NULL, CAP_DAC_READ_SEARCH, SUSER_ALLOWJAIL))
cap_granted |= VEXEC;
} else {
if ((acc_mode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
!cap_check(cred, NULL, CAP_DAC_EXECUTE, SUSER_ALLOWJAIL))
cap_granted |= VEXEC;
}
if ((acc_mode & VREAD) && ((dac_granted & VREAD) == 0) &&
!cap_check(cred, NULL, CAP_DAC_READ_SEARCH, SUSER_ALLOWJAIL))
cap_granted |= VREAD;
if ((acc_mode & VWRITE) && ((dac_granted & VWRITE) == 0) &&
!cap_check(cred, NULL, CAP_DAC_WRITE, SUSER_ALLOWJAIL))
cap_granted |= (VWRITE | VAPPEND);
if ((acc_mode & VADMIN) && ((dac_granted & VADMIN) == 0) &&
!cap_check(cred, NULL, CAP_FOWNER, SUSER_ALLOWJAIL))
cap_granted |= VADMIN;
if ((acc_mode & (cap_granted | dac_granted)) == acc_mode) {
/* XXX audit: privilege used */
if (privused != NULL)
*privused = 1;
return (0);
}
#endif
return ((acc_mode & VADMIN) ? EPERM : EACCES);
}
/*
* Credential check based on process requesting service, and per-attribute
* permissions.
*/
int
extattr_check_cred(struct vnode *vp, int attrnamespace,
struct ucred *cred, struct thread *td, int access)
{
/*
* Kernel-invoked always succeeds.
*/
if (cred == NOCRED)
return (0);
/*
* Do not allow privileged processes in jail to directly
* manipulate system attributes.
*
* XXX What capability should apply here?
* Probably CAP_SYS_SETFFLAG.
*/
switch (attrnamespace) {
case EXTATTR_NAMESPACE_SYSTEM:
/* Potentially should be: return (EPERM); */
return (suser_cred(cred, 0));
case EXTATTR_NAMESPACE_USER:
return (VOP_ACCESS(vp, access, cred, td));
default:
return (EPERM);
}
}
#ifdef DEBUG_VFS_LOCKS
/*
* This only exists to supress warnings from unlocked specfs accesses. It is
* no longer ok to have an unlocked VFS.
*/
#define IGNORE_LOCK(vp) ((vp)->v_type == VCHR || (vp)->v_type == VBAD)
int vfs_badlock_ddb = 1; /* Drop into debugger on violation. */
SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_ddb, CTLFLAG_RW, &vfs_badlock_ddb, 0, "");
int vfs_badlock_mutex = 1; /* Check for interlock across VOPs. */
SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_mutex, CTLFLAG_RW, &vfs_badlock_mutex, 0, "");
int vfs_badlock_print = 1; /* Print lock violations. */
SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_print, CTLFLAG_RW, &vfs_badlock_print, 0, "");
#ifdef KDB
int vfs_badlock_backtrace = 1; /* Print backtrace at lock violations. */
SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_backtrace, CTLFLAG_RW, &vfs_badlock_backtrace, 0, "");
#endif
static void
vfs_badlock(const char *msg, const char *str, struct vnode *vp)
{
#ifdef KDB
if (vfs_badlock_backtrace)
kdb_backtrace();
#endif
if (vfs_badlock_print)
printf("%s: %p %s\n", str, (void *)vp, msg);
if (vfs_badlock_ddb)
kdb_enter("lock violation");
}
void
assert_vi_locked(struct vnode *vp, const char *str)
{
if (vfs_badlock_mutex && !mtx_owned(VI_MTX(vp)))
vfs_badlock("interlock is not locked but should be", str, vp);
}
void
assert_vi_unlocked(struct vnode *vp, const char *str)
{
if (vfs_badlock_mutex && mtx_owned(VI_MTX(vp)))
vfs_badlock("interlock is locked but should not be", str, vp);
}
void
assert_vop_locked(struct vnode *vp, const char *str)
{
if (vp && !IGNORE_LOCK(vp) && VOP_ISLOCKED(vp, NULL) == 0)
vfs_badlock("is not locked but should be", str, vp);
}
void
assert_vop_unlocked(struct vnode *vp, const char *str)
{
if (vp && !IGNORE_LOCK(vp) &&
VOP_ISLOCKED(vp, curthread) == LK_EXCLUSIVE)
vfs_badlock("is locked but should not be", str, vp);
}
#if 0
void
assert_vop_elocked(struct vnode *vp, const char *str)
{
if (vp && !IGNORE_LOCK(vp) &&
VOP_ISLOCKED(vp, curthread) != LK_EXCLUSIVE)
vfs_badlock("is not exclusive locked but should be", str, vp);
}
void
assert_vop_elocked_other(struct vnode *vp, const char *str)
{
if (vp && !IGNORE_LOCK(vp) &&
VOP_ISLOCKED(vp, curthread) != LK_EXCLOTHER)
vfs_badlock("is not exclusive locked by another thread",
str, vp);
}
void
assert_vop_slocked(struct vnode *vp, const char *str)
{
if (vp && !IGNORE_LOCK(vp) &&
VOP_ISLOCKED(vp, curthread) != LK_SHARED)
vfs_badlock("is not locked shared but should be", str, vp);
}
#endif /* 0 */
void
vop_rename_pre(void *ap)
{
struct vop_rename_args *a = ap;
if (a->a_tvp)
ASSERT_VI_UNLOCKED(a->a_tvp, "VOP_RENAME");
ASSERT_VI_UNLOCKED(a->a_tdvp, "VOP_RENAME");
ASSERT_VI_UNLOCKED(a->a_fvp, "VOP_RENAME");
ASSERT_VI_UNLOCKED(a->a_fdvp, "VOP_RENAME");
/* Check the source (from). */
if (a->a_tdvp != a->a_fdvp)
ASSERT_VOP_UNLOCKED(a->a_fdvp, "vop_rename: fdvp locked");
if (a->a_tvp != a->a_fvp)
ASSERT_VOP_UNLOCKED(a->a_fvp, "vop_rename: tvp locked");
/* Check the target. */
if (a->a_tvp)
ASSERT_VOP_LOCKED(a->a_tvp, "vop_rename: tvp not locked");
ASSERT_VOP_LOCKED(a->a_tdvp, "vop_rename: tdvp not locked");
}
void
vop_strategy_pre(void *ap)
{
struct vop_strategy_args *a;
struct buf *bp;
a = ap;
bp = a->a_bp;
/*
* Cluster ops lock their component buffers but not the IO container.
*/
if ((bp->b_flags & B_CLUSTER) != 0)
return;
if (BUF_REFCNT(bp) < 1) {
if (vfs_badlock_print)
printf(
"VOP_STRATEGY: bp is not locked but should be\n");
if (vfs_badlock_ddb)
kdb_enter("lock violation");
}
}
void
vop_lookup_pre(void *ap)
{
struct vop_lookup_args *a;
struct vnode *dvp;
a = ap;
dvp = a->a_dvp;
ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP");
}
void
vop_lookup_post(void *ap, int rc)
{
struct vop_lookup_args *a;
struct componentname *cnp;
struct vnode *dvp;
struct vnode *vp;
int flags;
a = ap;
dvp = a->a_dvp;
cnp = a->a_cnp;
vp = *(a->a_vpp);
flags = cnp->cn_flags;
ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
/*
* If this is the last path component for this lookup and LOCKPARENT
* is set, OR if there is an error the directory has to be locked.
*/
if ((flags & LOCKPARENT) && (flags & ISLASTCN))
ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP (LOCKPARENT)");
else if (rc != 0)
ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP (error)");
else if (dvp != vp)
ASSERT_VOP_UNLOCKED(dvp, "VOP_LOOKUP (dvp)");
if (flags & PDIRUNLOCK)
ASSERT_VOP_UNLOCKED(dvp, "VOP_LOOKUP (PDIRUNLOCK)");
}
void
vop_lock_pre(void *ap)
{
struct vop_lock_args *a = ap;
if ((a->a_flags & LK_INTERLOCK) == 0)
ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
else
ASSERT_VI_LOCKED(a->a_vp, "VOP_LOCK");
}
void
vop_lock_post(void *ap, int rc)
{
struct vop_lock_args *a = ap;
ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
if (rc == 0)
ASSERT_VOP_LOCKED(a->a_vp, "VOP_LOCK");
}
void
vop_unlock_pre(void *ap)
{
struct vop_unlock_args *a = ap;
if (a->a_flags & LK_INTERLOCK)
ASSERT_VI_LOCKED(a->a_vp, "VOP_UNLOCK");
ASSERT_VOP_LOCKED(a->a_vp, "VOP_UNLOCK");
}
void
vop_unlock_post(void *ap, int rc)
{
struct vop_unlock_args *a = ap;
if (a->a_flags & LK_INTERLOCK)
ASSERT_VI_UNLOCKED(a->a_vp, "VOP_UNLOCK");
}
#endif /* DEBUG_VFS_LOCKS */
static struct knlist fs_knlist;
static void
vfs_event_init(void *arg)
{
knlist_init(&fs_knlist, NULL);
}
/* XXX - correct order? */
SYSINIT(vfs_knlist, SI_SUB_VFS, SI_ORDER_ANY, vfs_event_init, NULL);
void
vfs_event_signal(fsid_t *fsid, u_int32_t event, intptr_t data __unused)
{
KNOTE_UNLOCKED(&fs_knlist, event);
}
static int filt_fsattach(struct knote *kn);
static void filt_fsdetach(struct knote *kn);
static int filt_fsevent(struct knote *kn, long hint);
struct filterops fs_filtops =
{ 0, filt_fsattach, filt_fsdetach, filt_fsevent };
static int
filt_fsattach(struct knote *kn)
{
kn->kn_flags |= EV_CLEAR;
knlist_add(&fs_knlist, kn, 0);
return (0);
}
static void
filt_fsdetach(struct knote *kn)
{
knlist_remove(&fs_knlist, kn, 0);
}
static int
filt_fsevent(struct knote *kn, long hint)
{
kn->kn_fflags |= hint;
return (kn->kn_fflags != 0);
}
static int
sysctl_vfs_ctl(SYSCTL_HANDLER_ARGS)
{
struct vfsidctl vc;
int error;
struct mount *mp;
error = SYSCTL_IN(req, &vc, sizeof(vc));
if (error)
return (error);
if (vc.vc_vers != VFS_CTL_VERS1)
return (EINVAL);
mp = vfs_getvfs(&vc.vc_fsid);
if (mp == NULL)
return (ENOENT);
/* ensure that a specific sysctl goes to the right filesystem. */
if (strcmp(vc.vc_fstypename, "*") != 0 &&
strcmp(vc.vc_fstypename, mp->mnt_vfc->vfc_name) != 0) {
return (EINVAL);
}
VCTLTOREQ(&vc, req);
return (VFS_SYSCTL(mp, vc.vc_op, req));
}
SYSCTL_PROC(_vfs, OID_AUTO, ctl, CTLFLAG_WR,
NULL, 0, sysctl_vfs_ctl, "", "Sysctl by fsid");
/*
* Function to initialize a va_filerev field sensibly.
* XXX: Wouldn't a random number make a lot more sense ??
*/
u_quad_t
init_va_filerev(void)
{
struct bintime bt;
getbinuptime(&bt);
return (((u_quad_t)bt.sec << 32LL) | (bt.frac >> 32LL));
}
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