/
vfs_subr.c
1852 lines (1616 loc) · 45.3 KB
/
vfs_subr.c
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/* $NetBSD: vfs_subr.c,v 1.500 2023/04/30 08:46:11 riastradh Exp $ */
/*-
* Copyright (c) 1997, 1998, 2004, 2005, 2007, 2008, 2019, 2020
* The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center, by Charles M. Hannum, by Andrew Doran,
* by Marshall Kirk McKusick and Greg Ganger at the University of Michigan.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vfs_subr.c 8.13 (Berkeley) 4/18/94
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_subr.c,v 1.500 2023/04/30 08:46:11 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_compat_43.h"
#include "opt_compat_netbsd.h"
#include "opt_ddb.h"
#endif
#include <sys/param.h>
#include <sys/types.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/dirent.h>
#include <sys/errno.h>
#include <sys/filedesc.h>
#include <sys/fstrans.h>
#include <sys/kauth.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/module.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/stat.h>
#include <sys/syscallargs.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/vnode_impl.h>
#include <miscfs/deadfs/deadfs.h>
#include <miscfs/genfs/genfs.h>
#include <miscfs/specfs/specdev.h>
#include <uvm/uvm_ddb.h>
SDT_PROBE_DEFINE3(vfs, syncer, worklist, vnode__add,
"struct vnode *"/*vp*/,
"int"/*delayx*/,
"int"/*slot*/);
SDT_PROBE_DEFINE4(vfs, syncer, worklist, vnode__update,
"struct vnode *"/*vp*/,
"int"/*delayx*/,
"int"/*oslot*/,
"int"/*nslot*/);
SDT_PROBE_DEFINE1(vfs, syncer, worklist, vnode__remove,
"struct vnode *"/*vp*/);
SDT_PROBE_DEFINE3(vfs, syncer, worklist, mount__add,
"struct mount *"/*mp*/,
"int"/*vdelay*/,
"int"/*slot*/);
SDT_PROBE_DEFINE4(vfs, syncer, worklist, mount__update,
"struct mount *"/*vp*/,
"int"/*vdelay*/,
"int"/*oslot*/,
"int"/*nslot*/);
SDT_PROBE_DEFINE1(vfs, syncer, worklist, mount__remove,
"struct mount *"/*mp*/);
SDT_PROBE_DEFINE1(vfs, syncer, sync, start,
"int"/*starttime*/);
SDT_PROBE_DEFINE1(vfs, syncer, sync, mount__start,
"struct mount *"/*mp*/);
SDT_PROBE_DEFINE2(vfs, syncer, sync, mount__done,
"struct mount *"/*mp*/,
"int"/*error*/);
SDT_PROBE_DEFINE1(vfs, syncer, sync, mount__skip,
"struct mount *"/*mp*/);
SDT_PROBE_DEFINE1(vfs, syncer, sync, vnode__start,
"struct vnode *"/*vp*/);
SDT_PROBE_DEFINE2(vfs, syncer, sync, vnode__done,
"struct vnode *"/*vp*/,
"int"/*error*/);
SDT_PROBE_DEFINE2(vfs, syncer, sync, vnode__fail__lock,
"struct vnode *"/*vp*/,
"int"/*error*/);
SDT_PROBE_DEFINE2(vfs, syncer, sync, vnode__fail__vget,
"struct vnode *"/*vp*/,
"int"/*error*/);
SDT_PROBE_DEFINE2(vfs, syncer, sync, done,
"int"/*starttime*/,
"int"/*endtime*/);
const enum vtype iftovt_tab[16] = {
VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
};
const 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; \
}
int doforce = 1; /* 1 => permit forcible unmounting */
/*
* Local declarations.
*/
static void vn_initialize_syncerd(void);
/*
* Initialize the vnode management data structures.
*/
void
vntblinit(void)
{
vn_initialize_syncerd();
vfs_mount_sysinit();
vfs_vnode_sysinit();
}
/*
* Flush out and invalidate all buffers associated with a vnode.
* Called with the underlying vnode locked, which should prevent new dirty
* buffers from being queued.
*/
int
vinvalbuf(struct vnode *vp, int flags, kauth_cred_t cred, struct lwp *l,
bool catch_p, int slptimeo)
{
struct buf *bp, *nbp;
int error;
int flushflags = PGO_ALLPAGES | PGO_FREE | PGO_SYNCIO |
(flags & V_SAVE ? PGO_CLEANIT | PGO_RECLAIM : 0);
/* XXXUBC this doesn't look at flags or slp* */
rw_enter(vp->v_uobj.vmobjlock, RW_WRITER);
error = VOP_PUTPAGES(vp, 0, 0, flushflags);
if (error) {
return error;
}
if (flags & V_SAVE) {
error = VOP_FSYNC(vp, cred, FSYNC_WAIT|FSYNC_RECLAIM, 0, 0);
if (error)
return (error);
KASSERT(LIST_EMPTY(&vp->v_dirtyblkhd));
}
mutex_enter(&bufcache_lock);
restart:
for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
KASSERT(bp->b_vp == vp);
nbp = LIST_NEXT(bp, b_vnbufs);
error = bbusy(bp, catch_p, slptimeo, NULL);
if (error != 0) {
if (error == EPASSTHROUGH)
goto restart;
mutex_exit(&bufcache_lock);
return (error);
}
brelsel(bp, BC_INVAL | BC_VFLUSH);
}
for (bp = LIST_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) {
KASSERT(bp->b_vp == vp);
nbp = LIST_NEXT(bp, b_vnbufs);
error = bbusy(bp, catch_p, slptimeo, NULL);
if (error != 0) {
if (error == EPASSTHROUGH)
goto restart;
mutex_exit(&bufcache_lock);
return (error);
}
/*
* 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_oflags & BO_DELWRI) && (flags & V_SAVE)) {
#ifdef DEBUG
printf("buffer still DELWRI\n");
#endif
bp->b_cflags |= BC_BUSY | BC_VFLUSH;
mutex_exit(&bufcache_lock);
VOP_BWRITE(bp->b_vp, bp);
mutex_enter(&bufcache_lock);
goto restart;
}
brelsel(bp, BC_INVAL | BC_VFLUSH);
}
#ifdef DIAGNOSTIC
if (!LIST_EMPTY(&vp->v_cleanblkhd) || !LIST_EMPTY(&vp->v_dirtyblkhd))
panic("vinvalbuf: flush failed, vp %p", vp);
#endif
mutex_exit(&bufcache_lock);
return (0);
}
/*
* Destroy any in core blocks past the truncation length.
* Called with the underlying vnode locked, which should prevent new dirty
* buffers from being queued.
*/
int
vtruncbuf(struct vnode *vp, daddr_t lbn, bool catch_p, int slptimeo)
{
struct buf *bp, *nbp;
int error;
voff_t off;
off = round_page((voff_t)lbn << vp->v_mount->mnt_fs_bshift);
rw_enter(vp->v_uobj.vmobjlock, RW_WRITER);
error = VOP_PUTPAGES(vp, off, 0, PGO_FREE | PGO_SYNCIO);
if (error) {
return error;
}
mutex_enter(&bufcache_lock);
restart:
for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
KASSERT(bp->b_vp == vp);
nbp = LIST_NEXT(bp, b_vnbufs);
if (bp->b_lblkno < lbn)
continue;
error = bbusy(bp, catch_p, slptimeo, NULL);
if (error != 0) {
if (error == EPASSTHROUGH)
goto restart;
mutex_exit(&bufcache_lock);
return (error);
}
brelsel(bp, BC_INVAL | BC_VFLUSH);
}
for (bp = LIST_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) {
KASSERT(bp->b_vp == vp);
nbp = LIST_NEXT(bp, b_vnbufs);
if (bp->b_lblkno < lbn)
continue;
error = bbusy(bp, catch_p, slptimeo, NULL);
if (error != 0) {
if (error == EPASSTHROUGH)
goto restart;
mutex_exit(&bufcache_lock);
return (error);
}
brelsel(bp, BC_INVAL | BC_VFLUSH);
}
mutex_exit(&bufcache_lock);
return (0);
}
/*
* Flush all dirty buffers from a vnode.
* Called with the underlying vnode locked, which should prevent new dirty
* buffers from being queued.
*/
int
vflushbuf(struct vnode *vp, int flags)
{
struct buf *bp, *nbp;
int error, pflags;
bool dirty, sync;
sync = (flags & FSYNC_WAIT) != 0;
pflags = PGO_CLEANIT | PGO_ALLPAGES |
(sync ? PGO_SYNCIO : 0) |
((flags & FSYNC_LAZY) ? PGO_LAZY : 0);
rw_enter(vp->v_uobj.vmobjlock, RW_WRITER);
(void) VOP_PUTPAGES(vp, 0, 0, pflags);
loop:
mutex_enter(&bufcache_lock);
for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
KASSERT(bp->b_vp == vp);
nbp = LIST_NEXT(bp, b_vnbufs);
if ((bp->b_cflags & BC_BUSY))
continue;
if ((bp->b_oflags & BO_DELWRI) == 0)
panic("vflushbuf: not dirty, bp %p", bp);
bp->b_cflags |= BC_BUSY | BC_VFLUSH;
mutex_exit(&bufcache_lock);
/*
* Wait for I/O associated with indirect blocks to complete,
* since there is no way to quickly wait for them below.
*/
if (bp->b_vp == vp || !sync)
(void) bawrite(bp);
else {
error = bwrite(bp);
if (error)
return error;
}
goto loop;
}
mutex_exit(&bufcache_lock);
if (!sync)
return 0;
mutex_enter(vp->v_interlock);
while (vp->v_numoutput != 0)
cv_wait(&vp->v_cv, vp->v_interlock);
dirty = !LIST_EMPTY(&vp->v_dirtyblkhd);
mutex_exit(vp->v_interlock);
if (dirty) {
vprint("vflushbuf: dirty", vp);
goto loop;
}
return 0;
}
/*
* Create a vnode for a block device.
* Used for root filesystem and swap areas.
* Also used for memory file system special devices.
*/
int
bdevvp(dev_t dev, vnode_t **vpp)
{
struct vattr va;
vattr_null(&va);
va.va_type = VBLK;
va.va_rdev = dev;
return vcache_new(dead_rootmount, NULL, &va, NOCRED, NULL, vpp);
}
/*
* Create a vnode for a character device.
* Used for kernfs and some console handling.
*/
int
cdevvp(dev_t dev, vnode_t **vpp)
{
struct vattr va;
vattr_null(&va);
va.va_type = VCHR;
va.va_rdev = dev;
return vcache_new(dead_rootmount, NULL, &va, NOCRED, NULL, vpp);
}
/*
* Associate a buffer with a vnode. There must already be a hold on
* the vnode.
*/
void
bgetvp(struct vnode *vp, struct buf *bp)
{
KASSERT(bp->b_vp == NULL);
KASSERT(bp->b_objlock == &buffer_lock);
KASSERT(mutex_owned(vp->v_interlock));
KASSERT(mutex_owned(&bufcache_lock));
KASSERT((bp->b_cflags & BC_BUSY) != 0);
KASSERT(!cv_has_waiters(&bp->b_done));
vholdl(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.
*/
bufinsvn(bp, &vp->v_cleanblkhd);
bp->b_objlock = vp->v_interlock;
}
/*
* Disassociate a buffer from a vnode.
*/
void
brelvp(struct buf *bp)
{
struct vnode *vp = bp->b_vp;
KASSERT(vp != NULL);
KASSERT(bp->b_objlock == vp->v_interlock);
KASSERT(mutex_owned(vp->v_interlock));
KASSERT(mutex_owned(&bufcache_lock));
KASSERT((bp->b_cflags & BC_BUSY) != 0);
KASSERT(!cv_has_waiters(&bp->b_done));
/*
* Delete from old vnode list, if on one.
*/
if (LIST_NEXT(bp, b_vnbufs) != NOLIST)
bufremvn(bp);
if ((vp->v_iflag & (VI_ONWORKLST | VI_PAGES)) == VI_ONWORKLST &&
LIST_FIRST(&vp->v_dirtyblkhd) == NULL)
vn_syncer_remove_from_worklist(vp);
bp->b_objlock = &buffer_lock;
bp->b_vp = NULL;
holdrelel(vp);
}
/*
* Reassign a buffer from one vnode list to another.
* The list reassignment must be within the same vnode.
* Used to assign file specific control information
* (indirect blocks) to the list to which they belong.
*/
void
reassignbuf(struct buf *bp, struct vnode *vp)
{
struct buflists *listheadp;
int delayx;
KASSERT(mutex_owned(&bufcache_lock));
KASSERT(bp->b_objlock == vp->v_interlock);
KASSERT(mutex_owned(vp->v_interlock));
KASSERT((bp->b_cflags & BC_BUSY) != 0);
/*
* Delete from old vnode list, if on one.
*/
if (LIST_NEXT(bp, b_vnbufs) != NOLIST)
bufremvn(bp);
/*
* If dirty, put on list of dirty buffers;
* otherwise insert onto list of clean buffers.
*/
if ((bp->b_oflags & BO_DELWRI) == 0) {
listheadp = &vp->v_cleanblkhd;
if ((vp->v_iflag & (VI_ONWORKLST | VI_PAGES)) ==
VI_ONWORKLST &&
LIST_FIRST(&vp->v_dirtyblkhd) == NULL)
vn_syncer_remove_from_worklist(vp);
} else {
listheadp = &vp->v_dirtyblkhd;
if ((vp->v_iflag & VI_ONWORKLST) == 0) {
switch (vp->v_type) {
case VDIR:
delayx = dirdelay;
break;
case VBLK:
if (spec_node_getmountedfs(vp) != NULL) {
delayx = metadelay;
break;
}
/* fall through */
default:
delayx = filedelay;
break;
}
if (!vp->v_mount ||
(vp->v_mount->mnt_flag & MNT_ASYNC) == 0)
vn_syncer_add_to_worklist(vp, delayx);
}
}
bufinsvn(bp, listheadp);
}
/*
* Lookup a vnode by device number and return it referenced.
*/
int
vfinddev(dev_t dev, enum vtype type, vnode_t **vpp)
{
return (spec_node_lookup_by_dev(type, dev, VDEAD_NOWAIT, vpp) == 0);
}
/*
* Revoke all the vnodes corresponding to the specified minor number
* range (endpoints inclusive) of the specified major.
*/
void
vdevgone(int maj, int minl, int minh, enum vtype type)
{
vnode_t *vp;
dev_t dev;
int mn;
for (mn = minl; mn <= minh; mn++) {
dev = makedev(maj, mn);
/*
* Notify anyone trying to get at this device that it
* has been detached, and then revoke it.
*/
switch (type) {
case VBLK:
bdev_detached(dev);
break;
case VCHR:
cdev_detached(dev);
break;
default:
panic("invalid specnode type: %d", type);
}
/*
* Passing 0 as flags, instead of VDEAD_NOWAIT, means
* spec_node_lookup_by_dev will wait for vnodes it
* finds concurrently being revoked before returning.
*/
while (spec_node_lookup_by_dev(type, dev, 0, &vp) == 0) {
VOP_REVOKE(vp, REVOKEALL);
vrele(vp);
}
}
}
/*
* The filesystem synchronizer mechanism - syncer.
*
* It is useful to delay writes of file data and filesystem metadata for
* a certain amount of time so that quickly created and deleted files need
* not waste disk bandwidth being created and removed. To implement this,
* vnodes are appended to a "workitem" queue.
*
* Most pending metadata should not wait for more than ten 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.
*
* There are SYNCER_MAXDELAY queues that are processed in a round-robin
* manner at a rate of one each second (driven off the filesystem syner
* thread). 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 e.g. fifteen seconds is done by placing the request fifteen
* entries later in the queue:
*
* syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
*
* Flag VI_ONWORKLST indicates that vnode is added into the queue.
*/
#define SYNCER_MAXDELAY 32
typedef TAILQ_HEAD(synclist, vnode_impl) synclist_t;
static void vn_syncer_add1(struct vnode *, int);
static void sysctl_vfs_syncfs_setup(struct sysctllog **);
/*
* Defines and variables for the syncer process.
*/
int syncer_maxdelay = SYNCER_MAXDELAY; /* maximum delay time */
time_t syncdelay = 30; /* max time to delay syncing data */
time_t filedelay = 30; /* time to delay syncing files */
time_t dirdelay = 15; /* time to delay syncing directories */
time_t metadelay = 10; /* time to delay syncing metadata */
time_t lockdelay = 1; /* time to delay if locking fails */
static kmutex_t syncer_data_lock; /* short term lock on data structs */
static int syncer_delayno = 0;
static long syncer_last;
static synclist_t * syncer_workitem_pending;
static void
vn_initialize_syncerd(void)
{
int i;
syncer_last = SYNCER_MAXDELAY + 2;
sysctl_vfs_syncfs_setup(NULL);
syncer_workitem_pending =
kmem_alloc(syncer_last * sizeof (struct synclist), KM_SLEEP);
for (i = 0; i < syncer_last; i++)
TAILQ_INIT(&syncer_workitem_pending[i]);
mutex_init(&syncer_data_lock, MUTEX_DEFAULT, IPL_NONE);
}
/*
* Return delay factor appropriate for the given file system. For
* WAPBL we use the sync vnode to burst out metadata updates: sync
* those file systems more frequently.
*/
static inline int
sync_delay(struct mount *mp)
{
return mp->mnt_wapbl != NULL ? metadelay : syncdelay;
}
/*
* Compute the next slot index from delay.
*/
static inline int
sync_delay_slot(int delayx)
{
if (delayx > syncer_maxdelay - 2)
delayx = syncer_maxdelay - 2;
return (syncer_delayno + delayx) % syncer_last;
}
/*
* Add an item to the syncer work queue.
*/
static void
vn_syncer_add1(struct vnode *vp, int delayx)
{
synclist_t *slp;
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
KASSERT(mutex_owned(&syncer_data_lock));
if (vp->v_iflag & VI_ONWORKLST) {
/*
* Remove in order to adjust the position of the vnode.
* Note: called from sched_sync(), which will not hold
* interlock, therefore we cannot modify v_iflag here.
*/
slp = &syncer_workitem_pending[vip->vi_synclist_slot];
TAILQ_REMOVE(slp, vip, vi_synclist);
} else {
KASSERT(mutex_owned(vp->v_interlock));
vp->v_iflag |= VI_ONWORKLST;
}
vip->vi_synclist_slot = sync_delay_slot(delayx);
slp = &syncer_workitem_pending[vip->vi_synclist_slot];
TAILQ_INSERT_TAIL(slp, vip, vi_synclist);
}
void
vn_syncer_add_to_worklist(struct vnode *vp, int delayx)
{
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
KASSERT(mutex_owned(vp->v_interlock));
mutex_enter(&syncer_data_lock);
vn_syncer_add1(vp, delayx);
SDT_PROBE3(vfs, syncer, worklist, vnode__add,
vp, delayx, vip->vi_synclist_slot);
mutex_exit(&syncer_data_lock);
}
/*
* Remove an item from the syncer work queue.
*/
void
vn_syncer_remove_from_worklist(struct vnode *vp)
{
synclist_t *slp;
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
KASSERT(mutex_owned(vp->v_interlock));
if (vp->v_iflag & VI_ONWORKLST) {
mutex_enter(&syncer_data_lock);
SDT_PROBE1(vfs, syncer, worklist, vnode__remove, vp);
vp->v_iflag &= ~VI_ONWORKLST;
slp = &syncer_workitem_pending[vip->vi_synclist_slot];
TAILQ_REMOVE(slp, vip, vi_synclist);
mutex_exit(&syncer_data_lock);
}
}
/*
* Add this mount point to the syncer.
*/
void
vfs_syncer_add_to_worklist(struct mount *mp)
{
static int start, incr, next;
int vdelay;
KASSERT(mutex_owned(mp->mnt_updating));
KASSERT((mp->mnt_iflag & IMNT_ONWORKLIST) == 0);
/*
* We attempt to scatter the mount points 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;
}
mp->mnt_iflag |= IMNT_ONWORKLIST;
vdelay = sync_delay(mp);
mp->mnt_synclist_slot = vdelay > 0 ? next % vdelay : 0;
SDT_PROBE3(vfs, syncer, worklist, mount__add,
mp, vdelay, mp->mnt_synclist_slot);
}
/*
* Remove the mount point from the syncer.
*/
void
vfs_syncer_remove_from_worklist(struct mount *mp)
{
KASSERT(mutex_owned(mp->mnt_updating));
KASSERT((mp->mnt_iflag & IMNT_ONWORKLIST) != 0);
SDT_PROBE1(vfs, syncer, worklist, mount__remove, mp);
mp->mnt_iflag &= ~IMNT_ONWORKLIST;
}
/*
* Try lazy sync, return true on success.
*/
static bool
lazy_sync_vnode(struct vnode *vp)
{
bool synced;
int error;
KASSERT(mutex_owned(&syncer_data_lock));
synced = false;
if ((error = vcache_tryvget(vp)) == 0) {
mutex_exit(&syncer_data_lock);
if ((error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT)) == 0) {
synced = true;
SDT_PROBE1(vfs, syncer, sync, vnode__start, vp);
error = VOP_FSYNC(vp, curlwp->l_cred,
FSYNC_LAZY, 0, 0);
SDT_PROBE2(vfs, syncer, sync, vnode__done, vp, error);
vput(vp);
} else {
SDT_PROBE2(vfs, syncer, sync, vnode__fail__lock,
vp, error);
vrele(vp);
}
mutex_enter(&syncer_data_lock);
} else {
SDT_PROBE2(vfs, syncer, sync, vnode__fail__vget, vp, error);
}
return synced;
}
/*
* System filesystem synchronizer daemon.
*/
void
sched_sync(void *arg)
{
mount_iterator_t *iter;
synclist_t *slp;
struct vnode_impl *vi;
struct vnode *vp;
struct mount *mp;
time_t starttime, endtime;
int vdelay, oslot, nslot, delayx;
bool synced;
int error;
for (;;) {
starttime = time_second;
SDT_PROBE1(vfs, syncer, sync, start, starttime);
/*
* Sync mounts whose dirty time has expired.
*/
mountlist_iterator_init(&iter);
while ((mp = mountlist_iterator_trynext(iter)) != NULL) {
if ((mp->mnt_iflag & IMNT_ONWORKLIST) == 0 ||
mp->mnt_synclist_slot != syncer_delayno) {
SDT_PROBE1(vfs, syncer, sync, mount__skip,
mp);
continue;
}
vdelay = sync_delay(mp);
oslot = mp->mnt_synclist_slot;
nslot = sync_delay_slot(vdelay);
mp->mnt_synclist_slot = nslot;
SDT_PROBE4(vfs, syncer, worklist, mount__update,
mp, vdelay, oslot, nslot);
SDT_PROBE1(vfs, syncer, sync, mount__start, mp);
error = VFS_SYNC(mp, MNT_LAZY, curlwp->l_cred);
SDT_PROBE2(vfs, syncer, sync, mount__done,
mp, error);
}
mountlist_iterator_destroy(iter);
mutex_enter(&syncer_data_lock);
/*
* Push files whose dirty time has expired.
*/
slp = &syncer_workitem_pending[syncer_delayno];
syncer_delayno += 1;
if (syncer_delayno >= syncer_last)
syncer_delayno = 0;
while ((vi = TAILQ_FIRST(slp)) != NULL) {
vp = VIMPL_TO_VNODE(vi);
synced = lazy_sync_vnode(vp);
/*
* XXX The vnode may have been recycled, in which
* case it may have a new identity.
*/
vi = TAILQ_FIRST(slp);
if (vi != NULL && VIMPL_TO_VNODE(vi) == vp) {
/*
* 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.
*
* Try again sooner rather than later if
* we were unable to lock the vnode. Lock
* failure should not prevent us from doing
* the sync "soon".
*
* If we locked it yet arrive here, it's
* likely that lazy sync is in progress and
* so the vnode still has dirty metadata.
* syncdelay is mainly to get this vnode out
* of the way so we do not consider it again
* "soon" in this loop, so the delay time is
* not critical as long as it is not "soon".
* While write-back strategy is the file
* system's domain, we expect write-back to
* occur no later than syncdelay seconds
* into the future.
*/
delayx = synced ? syncdelay : lockdelay;
oslot = vi->vi_synclist_slot;
vn_syncer_add1(vp, delayx);
nslot = vi->vi_synclist_slot;
SDT_PROBE4(vfs, syncer, worklist,
vnode__update,
vp, delayx, oslot, nslot);
}
}
endtime = time_second;
SDT_PROBE2(vfs, syncer, sync, done, starttime, endtime);
/*
* 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 (endtime == starttime) {
kpause("syncer", false, hz, &syncer_data_lock);
}
mutex_exit(&syncer_data_lock);
}
}
static void
sysctl_vfs_syncfs_setup(struct sysctllog **clog)
{
const struct sysctlnode *rnode, *cnode;
sysctl_createv(clog, 0, NULL, &rnode,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "sync",
SYSCTL_DESCR("syncer options"),
NULL, 0, NULL, 0,
CTL_VFS, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &rnode, &cnode,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_QUAD, "delay",
SYSCTL_DESCR("max time to delay syncing data"),
NULL, 0, &syncdelay, 0,
CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &rnode, &cnode,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_QUAD, "filedelay",
SYSCTL_DESCR("time to delay syncing files"),
NULL, 0, &filedelay, 0,
CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &rnode, &cnode,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_QUAD, "dirdelay",
SYSCTL_DESCR("time to delay syncing directories"),
NULL, 0, &dirdelay, 0,
CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &rnode, &cnode,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_QUAD, "metadelay",
SYSCTL_DESCR("time to delay syncing metadata"),
NULL, 0, &metadelay, 0,
CTL_CREATE, CTL_EOL);
}
/*
* sysctl helper routine to return list of supported fstypes
*/
int
sysctl_vfs_generic_fstypes(SYSCTLFN_ARGS)
{
char bf[sizeof(((struct statvfs *)NULL)->f_fstypename)];
char *where = oldp;
struct vfsops *v;
size_t needed, left, slen;
int error, first;