2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
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11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
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17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * @(#)vfs_subr.c 8.31 (Berkeley) 5/26/95
35 * $FreeBSD: src/sys/kern/vfs_subr.c,v 1.249.2.30 2003/04/04 20:35:57 tegge Exp $
39 * External virtual filesystem routines
42 #include <sys/param.h>
43 #include <sys/systm.h>
46 #include <sys/dirent.h>
47 #include <sys/domain.h>
48 #include <sys/eventhandler.h>
49 #include <sys/fcntl.h>
50 #include <sys/kernel.h>
51 #include <sys/kthread.h>
52 #include <sys/malloc.h>
54 #include <sys/mount.h>
56 #include <sys/reboot.h>
57 #include <sys/socket.h>
59 #include <sys/sysctl.h>
60 #include <sys/syslog.h>
61 #include <sys/vmmeter.h>
62 #include <sys/vnode.h>
64 #include <machine/limits.h>
67 #include <vm/vm_object.h>
68 #include <vm/vm_extern.h>
69 #include <vm/vm_kern.h>
71 #include <vm/vm_map.h>
72 #include <vm/vm_page.h>
73 #include <vm/vm_pager.h>
74 #include <vm/vnode_pager.h>
81 #define SYNCER_MAXDELAY 32
82 static int sysctl_kern_syncdelay(SYSCTL_HANDLER_ARGS
);
83 time_t syncdelay
= 30; /* max time to delay syncing data */
84 SYSCTL_PROC(_kern
, OID_AUTO
, syncdelay
, CTLTYPE_INT
| CTLFLAG_RW
, 0, 0,
85 sysctl_kern_syncdelay
, "I", "VFS data synchronization delay");
86 time_t filedelay
= 30; /* time to delay syncing files */
87 SYSCTL_INT(_kern
, OID_AUTO
, filedelay
, CTLFLAG_RW
,
88 &filedelay
, 0, "File synchronization delay");
89 time_t dirdelay
= 29; /* time to delay syncing directories */
90 SYSCTL_INT(_kern
, OID_AUTO
, dirdelay
, CTLFLAG_RW
,
91 &dirdelay
, 0, "Directory synchronization delay");
92 time_t metadelay
= 28; /* time to delay syncing metadata */
93 SYSCTL_INT(_kern
, OID_AUTO
, metadelay
, CTLFLAG_RW
,
94 &metadelay
, 0, "VFS metadata synchronization delay");
95 time_t retrydelay
= 1; /* retry delay after failure */
96 SYSCTL_INT(_kern
, OID_AUTO
, retrydelay
, CTLFLAG_RW
,
97 &retrydelay
, 0, "VFS retry synchronization delay");
98 static int rushjob
; /* number of slots to run ASAP */
99 static int stat_rush_requests
; /* number of times I/O speeded up */
100 SYSCTL_INT(_debug
, OID_AUTO
, rush_requests
, CTLFLAG_RW
,
101 &stat_rush_requests
, 0, "");
103 LIST_HEAD(synclist
, vnode
);
105 #define SC_FLAG_EXIT (0x1) /* request syncer exit */
106 #define SC_FLAG_DONE (0x2) /* syncer confirm exit */
110 struct lwkt_token sc_token
;
111 struct thread
*sc_thread
;
113 struct synclist
*syncer_workitem_pending
;
117 int syncer_rushjob
; /* sequence vnodes faster */
118 int syncer_trigger
; /* trigger full sync */
122 static void syncer_thread(void *);
125 sysctl_kern_syncdelay(SYSCTL_HANDLER_ARGS
)
130 error
= sysctl_handle_int(oidp
, &v
, 0, req
);
131 if (error
|| !req
->newptr
)
135 if (v
> SYNCER_MAXDELAY
)
143 * The workitem queue.
145 * It is useful to delay writes of file data and filesystem metadata
146 * for tens of seconds so that quickly created and deleted files need
147 * not waste disk bandwidth being created and removed. To realize this,
148 * we append vnodes to a "workitem" queue. When running with a soft
149 * updates implementation, most pending metadata dependencies should
150 * not wait for more than a few seconds. Thus, mounted on block devices
151 * are delayed only about a half the time that file data is delayed.
152 * Similarly, directory updates are more critical, so are only delayed
153 * about a third the time that file data is delayed. Thus, there are
154 * SYNCER_MAXDELAY queues that are processed round-robin at a rate of
155 * one each second (driven off the filesystem syncer process). The
156 * syncer_delayno variable indicates the next queue that is to be processed.
157 * Items that need to be processed soon are placed in this queue:
159 * syncer_workitem_pending[syncer_delayno]
161 * A delay of fifteen seconds is done by placing the request fifteen
162 * entries later in the queue:
164 * syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
169 * Return the number of vnodes on the syncer's timed list. This will
170 * include the syncer vnode (mp->mnt_syncer) so if used, a minimum
171 * value of 1 will be returned.
174 vn_syncer_count(struct mount
*mp
)
176 struct syncer_ctx
*ctx
;
178 ctx
= mp
->mnt_syncer_ctx
;
180 return (ctx
->syncer_count
);
185 * Add an item to the syncer work queue.
187 * WARNING: Cannot get vp->v_token here if not already held, we must
188 * depend on the syncer_token (which might already be held by
189 * the caller) to protect v_synclist and VONWORKLST.
191 * WARNING: The syncer depends on this function not blocking if the caller
192 * already holds the syncer token.
195 vn_syncer_add(struct vnode
*vp
, int delay
)
197 struct syncer_ctx
*ctx
;
200 ctx
= vp
->v_mount
->mnt_syncer_ctx
;
201 lwkt_gettoken(&ctx
->sc_token
);
203 if (vp
->v_flag
& VONWORKLST
) {
204 LIST_REMOVE(vp
, v_synclist
);
208 slot
= -delay
& ctx
->syncer_mask
;
210 if (delay
> SYNCER_MAXDELAY
- 2)
211 delay
= SYNCER_MAXDELAY
- 2;
212 slot
= (ctx
->syncer_delayno
+ delay
) & ctx
->syncer_mask
;
215 LIST_INSERT_HEAD(&ctx
->syncer_workitem_pending
[slot
], vp
, v_synclist
);
216 vsetflags(vp
, VONWORKLST
);
219 lwkt_reltoken(&ctx
->sc_token
);
223 * Removes the vnode from the syncer list. Since we might block while
224 * acquiring the syncer_token we have to [re]check conditions to determine
225 * that it is ok to remove the vnode.
227 * Force removal if force != 0. This can only occur during a forced unmount.
229 * vp->v_token held on call
232 vn_syncer_remove(struct vnode
*vp
, int force
)
234 struct syncer_ctx
*ctx
;
236 ctx
= vp
->v_mount
->mnt_syncer_ctx
;
237 lwkt_gettoken(&ctx
->sc_token
);
239 if ((vp
->v_flag
& (VISDIRTY
| VONWORKLST
| VOBJDIRTY
)) == VONWORKLST
&&
240 RB_EMPTY(&vp
->v_rbdirty_tree
)) {
241 vclrflags(vp
, VONWORKLST
);
242 LIST_REMOVE(vp
, v_synclist
);
244 } else if (force
&& (vp
->v_flag
& VONWORKLST
)) {
245 vclrflags(vp
, VONWORKLST
);
246 LIST_REMOVE(vp
, v_synclist
);
250 lwkt_reltoken(&ctx
->sc_token
);
254 * vnode must be locked
257 vclrisdirty(struct vnode
*vp
)
259 vclrflags(vp
, VISDIRTY
);
260 if (vp
->v_flag
& VONWORKLST
)
261 vn_syncer_remove(vp
, 0);
265 vclrobjdirty(struct vnode
*vp
)
267 vclrflags(vp
, VOBJDIRTY
);
268 if (vp
->v_flag
& VONWORKLST
)
269 vn_syncer_remove(vp
, 0);
273 * vnode must be stable
276 vsetisdirty(struct vnode
*vp
)
278 struct syncer_ctx
*ctx
;
280 if ((vp
->v_flag
& VISDIRTY
) == 0) {
281 ctx
= vp
->v_mount
->mnt_syncer_ctx
;
282 vsetflags(vp
, VISDIRTY
);
283 lwkt_gettoken(&ctx
->sc_token
);
284 if ((vp
->v_flag
& VONWORKLST
) == 0)
285 vn_syncer_add(vp
, syncdelay
);
286 lwkt_reltoken(&ctx
->sc_token
);
291 vsetobjdirty(struct vnode
*vp
)
293 struct syncer_ctx
*ctx
;
295 if ((vp
->v_flag
& VOBJDIRTY
) == 0) {
296 ctx
= vp
->v_mount
->mnt_syncer_ctx
;
297 vsetflags(vp
, VOBJDIRTY
);
298 lwkt_gettoken(&ctx
->sc_token
);
299 if ((vp
->v_flag
& VONWORKLST
) == 0)
300 vn_syncer_add(vp
, syncdelay
);
301 lwkt_reltoken(&ctx
->sc_token
);
306 * Create per-filesystem syncer process
309 vn_syncer_thr_create(struct mount
*mp
)
311 struct syncer_ctx
*ctx
;
312 static int syncalloc
= 0;
314 ctx
= kmalloc(sizeof(struct syncer_ctx
), M_TEMP
, M_WAITOK
| M_ZERO
);
317 ctx
->syncer_workitem_pending
= hashinit(SYNCER_MAXDELAY
, M_DEVBUF
,
319 ctx
->syncer_delayno
= 0;
320 lwkt_token_init(&ctx
->sc_token
, "syncer");
321 mp
->mnt_syncer_ctx
= ctx
;
322 kthread_create(syncer_thread
, ctx
, &ctx
->sc_thread
,
323 "syncer%d", ++syncalloc
& 0x7FFFFFFF);
327 * Stop per-filesystem syncer process
330 vn_syncer_thr_stop(struct mount
*mp
)
332 struct syncer_ctx
*ctx
;
334 ctx
= mp
->mnt_syncer_ctx
;
338 lwkt_gettoken(&ctx
->sc_token
);
340 /* Signal the syncer process to exit */
341 ctx
->sc_flags
|= SC_FLAG_EXIT
;
344 /* Wait till syncer process exits */
345 while ((ctx
->sc_flags
& SC_FLAG_DONE
) == 0) {
346 tsleep_interlock(&ctx
->sc_flags
, 0);
347 lwkt_reltoken(&ctx
->sc_token
);
348 tsleep(&ctx
->sc_flags
, PINTERLOCKED
, "syncexit", hz
);
349 lwkt_gettoken(&ctx
->sc_token
);
352 mp
->mnt_syncer_ctx
= NULL
;
353 lwkt_reltoken(&ctx
->sc_token
);
355 hashdestroy(ctx
->syncer_workitem_pending
, M_DEVBUF
, ctx
->syncer_mask
);
359 struct thread
*updatethread
;
362 * System filesystem synchronizer daemon.
365 syncer_thread(void *_ctx
)
367 struct syncer_ctx
*ctx
= _ctx
;
368 struct synclist
*slp
;
373 int vnodes_synced
= 0;
378 kproc_suspend_loop();
380 starttime
= time_uptime
;
381 lwkt_gettoken(&ctx
->sc_token
);
384 * Push files whose dirty time has expired. Be careful
385 * of interrupt race on slp queue.
387 * Note that vsyncscan() and vn_syncer_one() can pull items
388 * off the same list, so we shift vp's position in the
391 slp
= &ctx
->syncer_workitem_pending
[ctx
->syncer_delayno
];
394 * If syncer_trigger is set (from trigger_syncer(mp)),
395 * Immediately do a full filesystem sync and set up the
396 * following full filesystem sync to occur in 1 second.
398 if (ctx
->syncer_trigger
) {
399 ctx
->syncer_trigger
= 0;
400 if (ctx
->sc_mp
&& ctx
->sc_mp
->mnt_syncer
) {
401 vp
= ctx
->sc_mp
->mnt_syncer
;
402 if (vp
->v_flag
& VONWORKLST
) {
403 vn_syncer_add(vp
, retrydelay
);
404 if (vget(vp
, LK_EXCLUSIVE
) == 0) {
405 VOP_FSYNC(vp
, MNT_LAZY
, 0);
414 * FSYNC items in this bucket
416 while ((vp
= LIST_FIRST(slp
)) != NULL
) {
417 vn_syncer_add(vp
, retrydelay
);
418 if (ctx
->syncer_forced
) {
419 if (vget(vp
, LK_EXCLUSIVE
) == 0) {
420 VOP_FSYNC(vp
, MNT_NOWAIT
, 0);
425 if (vget(vp
, LK_EXCLUSIVE
| LK_NOWAIT
) == 0) {
426 VOP_FSYNC(vp
, MNT_LAZY
, 0);
434 * Increment the slot upon completion. This is typically
435 * one-second but may be faster if the syncer is triggered.
437 ctx
->syncer_delayno
= (ctx
->syncer_delayno
+ 1) &
440 sc_flags
= ctx
->sc_flags
;
442 /* Exit on unmount */
443 if (sc_flags
& SC_FLAG_EXIT
)
446 lwkt_reltoken(&ctx
->sc_token
);
449 * Do sync processing for each mount.
452 bio_ops_sync(ctx
->sc_mp
);
455 * The variable rushjob allows the kernel to speed up the
456 * processing of the filesystem syncer process. A rushjob
457 * value of N tells the filesystem syncer to process the next
458 * N seconds worth of work on its queue ASAP. Currently rushjob
459 * is used by the soft update code to speed up the filesystem
460 * syncer process when the incore state is getting so far
461 * ahead of the disk that the kernel memory pool is being
462 * threatened with exhaustion.
464 delta
= rushjob
- ctx
->syncer_rushjob
;
465 if ((u_int
)delta
> syncdelay
/ 2) {
466 ctx
->syncer_rushjob
= rushjob
- syncdelay
/ 2;
467 tsleep(&dummy
, 0, "rush", 1);
471 ++ctx
->syncer_rushjob
;
472 tsleep(&dummy
, 0, "rush", 1);
477 * Normal syncer operation iterates once a second, unless
478 * specifically triggered.
480 if (time_uptime
== starttime
&&
481 ctx
->syncer_trigger
== 0) {
482 tsleep_interlock(ctx
, 0);
483 if (time_uptime
== starttime
&&
484 ctx
->syncer_trigger
== 0 &&
485 (ctx
->sc_flags
& SC_FLAG_EXIT
) == 0) {
486 tsleep(ctx
, PINTERLOCKED
, "syncer", hz
);
492 * Unmount/exit path for per-filesystem syncers; sc_token held
494 ctx
->sc_flags
|= SC_FLAG_DONE
;
495 sc_flagsp
= &ctx
->sc_flags
;
496 lwkt_reltoken(&ctx
->sc_token
);
503 * This allows a filesystem to pro-actively request that a dirty
504 * vnode be fsync()d. This routine does not guarantee that one
505 * will actually be fsynced.
508 vn_syncer_one(struct mount
*mp
)
510 struct syncer_ctx
*ctx
;
511 struct synclist
*slp
;
516 ctx
= mp
->mnt_syncer_ctx
;
517 i
= ctx
->syncer_delayno
& ctx
->syncer_mask
;
520 if (lwkt_trytoken(&ctx
->sc_token
) == 0)
524 * Look ahead on our syncer time array.
527 slp
= &ctx
->syncer_workitem_pending
[i
];
528 vp
= LIST_FIRST(slp
);
529 if (vp
&& vp
->v_type
== VNON
)
530 vp
= LIST_NEXT(vp
, v_synclist
);
533 i
= (i
+ 1) & ctx
->syncer_mask
;
534 /* i will be wrong if we stop here but vp is NULL so ok */
538 * Process one vnode, skip the syncer vnode but also stop
539 * if the syncer vnode is the only thing on this list.
542 vn_syncer_add(vp
, retrydelay
);
543 if (vget(vp
, LK_EXCLUSIVE
| LK_NOWAIT
) == 0) {
544 VOP_FSYNC(vp
, MNT_LAZY
, 0);
548 lwkt_reltoken(&ctx
->sc_token
);
552 * Request that the syncer daemon for a specific mount speed up its work.
553 * If mp is NULL the caller generally wants to speed up all syncers.
556 speedup_syncer(struct mount
*mp
)
559 * Don't bother protecting the test. unsleep_and_wakeup_thread()
560 * will only do something real if the thread is in the right state.
562 atomic_add_int(&rushjob
, 1);
563 ++stat_rush_requests
;
564 if (mp
&& mp
->mnt_syncer_ctx
)
565 wakeup(mp
->mnt_syncer_ctx
);
569 * trigger a full sync
572 trigger_syncer(struct mount
*mp
)
574 struct syncer_ctx
*ctx
;
576 if (mp
&& (ctx
= mp
->mnt_syncer_ctx
) != NULL
) {
577 if (ctx
->syncer_trigger
== 0) {
578 ctx
->syncer_trigger
= 1;
585 * Routine to create and manage a filesystem syncer vnode.
587 static int sync_close(struct vop_close_args
*);
588 static int sync_fsync(struct vop_fsync_args
*);
589 static int sync_inactive(struct vop_inactive_args
*);
590 static int sync_reclaim (struct vop_reclaim_args
*);
591 static int sync_print(struct vop_print_args
*);
593 static struct vop_ops sync_vnode_vops
= {
594 .vop_default
= vop_eopnotsupp
,
595 .vop_close
= sync_close
,
596 .vop_fsync
= sync_fsync
,
597 .vop_inactive
= sync_inactive
,
598 .vop_reclaim
= sync_reclaim
,
599 .vop_print
= sync_print
,
602 static struct vop_ops
*sync_vnode_vops_p
= &sync_vnode_vops
;
604 VNODEOP_SET(sync_vnode_vops
);
607 * Create a new filesystem syncer vnode for the specified mount point.
608 * This vnode is placed on the worklist and is responsible for sync'ing
611 * NOTE: read-only mounts are also placed on the worklist. The filesystem
612 * sync code is also responsible for cleaning up vnodes.
615 vfs_allocate_syncvnode(struct mount
*mp
)
618 static long start
, incr
, next
;
621 /* Allocate a new vnode */
622 error
= getspecialvnode(VT_VFS
, mp
, &sync_vnode_vops_p
, &vp
, 0, 0);
624 mp
->mnt_syncer
= NULL
;
629 * Place the vnode onto the syncer worklist. We attempt to
630 * scatter them about on the list so that they will go off
631 * at evenly distributed times even if all the filesystems
632 * are mounted at once.
635 if (next
== 0 || next
> SYNCER_MAXDELAY
) {
639 start
= SYNCER_MAXDELAY
/ 2;
640 incr
= SYNCER_MAXDELAY
;
646 * Only put the syncer vnode onto the syncer list if we have a
647 * syncer thread. Some VFS's (aka NULLFS) don't need a syncer
650 if (mp
->mnt_syncer_ctx
)
651 vn_syncer_add(vp
, syncdelay
> 0 ? next
% syncdelay
: 0);
654 * The mnt_syncer field inherits the vnode reference, which is
655 * held until later decomissioning.
663 sync_close(struct vop_close_args
*ap
)
669 * Do a lazy sync of the filesystem.
671 * sync_fsync { struct vnode *a_vp, int a_waitfor }
674 sync_fsync(struct vop_fsync_args
*ap
)
676 struct vnode
*syncvp
= ap
->a_vp
;
677 struct mount
*mp
= syncvp
->v_mount
;
681 * We only need to do something if this is a lazy evaluation.
683 if ((ap
->a_waitfor
& MNT_LAZY
) == 0)
687 * Move ourselves to the back of the sync list.
689 vn_syncer_add(syncvp
, syncdelay
);
692 * Walk the list of vnodes pushing all that are dirty and
693 * not already on the sync list, and freeing vnodes which have
694 * no refs and whos VM objects are empty. vfs_msync() handles
695 * the VM issues and must be called whether the mount is readonly
698 if (vfs_busy(mp
, LK_NOWAIT
) != 0)
700 if (mp
->mnt_flag
& MNT_RDONLY
) {
701 vfs_msync(mp
, MNT_NOWAIT
);
703 asyncflag
= mp
->mnt_flag
& MNT_ASYNC
;
704 mp
->mnt_flag
&= ~MNT_ASYNC
; /* ZZZ hack */
705 vfs_msync(mp
, MNT_NOWAIT
);
706 VFS_SYNC(mp
, MNT_NOWAIT
| MNT_LAZY
);
708 mp
->mnt_flag
|= MNT_ASYNC
;
715 * The syncer vnode is no longer referenced.
717 * sync_inactive { struct vnode *a_vp, struct proc *a_p }
720 sync_inactive(struct vop_inactive_args
*ap
)
722 vgone_vxlocked(ap
->a_vp
);
727 * The syncer vnode is no longer needed and is being decommissioned.
728 * This can only occur when the last reference has been released on
729 * mp->mnt_syncer, so mp->mnt_syncer had better be NULL.
731 * Modifications to the worklist must be protected with a critical
734 * sync_reclaim { struct vnode *a_vp }
737 sync_reclaim(struct vop_reclaim_args
*ap
)
739 struct vnode
*vp
= ap
->a_vp
;
740 struct syncer_ctx
*ctx
;
742 ctx
= vp
->v_mount
->mnt_syncer_ctx
;
744 lwkt_gettoken(&ctx
->sc_token
);
745 KKASSERT(vp
->v_mount
->mnt_syncer
!= vp
);
746 if (vp
->v_flag
& VONWORKLST
) {
747 LIST_REMOVE(vp
, v_synclist
);
748 vclrflags(vp
, VONWORKLST
);
751 lwkt_reltoken(&ctx
->sc_token
);
753 KKASSERT((vp
->v_flag
& VONWORKLST
) == 0);
760 * This is very similar to vmntvnodescan() but it only scans the
761 * vnodes on the syncer list. VFS's which support faster VFS_SYNC
762 * operations use the VISDIRTY flag on the vnode to ensure that vnodes
763 * with dirty inodes are added to the syncer in addition to vnodes
764 * with dirty buffers, and can use this function instead of nmntvnodescan().
766 * This scan does not issue VOP_FSYNC()s. The supplied callback is intended
767 * to synchronize the file in the manner intended by the VFS using it.
769 * This is important when a system has millions of vnodes.
775 int (*slowfunc
)(struct mount
*mp
, struct vnode
*vp
, void *data
),
778 struct syncer_ctx
*ctx
;
779 struct synclist
*slp
;
785 if (vmsc_flags
& VMSC_NOWAIT
)
791 * Syncer list context. This API requires a dedicated syncer thread.
794 KKASSERT(mp
->mnt_kern_flag
& MNTK_THR_SYNC
);
795 ctx
= mp
->mnt_syncer_ctx
;
796 lwkt_gettoken(&ctx
->sc_token
);
799 * Setup for loop. Allow races against the syncer thread but
800 * require that the syncer thread no be lazy if we were told
803 i
= ctx
->syncer_delayno
& ctx
->syncer_mask
;
804 if ((vmsc_flags
& VMSC_NOWAIT
) == 0)
805 ++ctx
->syncer_forced
;
806 for (count
= 0; count
<= ctx
->syncer_mask
; ++count
) {
807 slp
= &ctx
->syncer_workitem_pending
[i
];
809 while ((vp
= LIST_FIRST(slp
)) != NULL
) {
810 KKASSERT(vp
->v_mount
== mp
);
811 if (vmsc_flags
& VMSC_GETVP
) {
812 if (vget(vp
, LK_EXCLUSIVE
| lkflags
) == 0) {
813 slowfunc(mp
, vp
, data
);
816 } else if (vmsc_flags
& VMSC_GETVX
) {
818 slowfunc(mp
, vp
, data
);
822 slowfunc(mp
, vp
, data
);
827 * vp could be invalid. However, if vp is still at
828 * the head of the list it is clearly valid and we
829 * can safely move it.
831 if (LIST_FIRST(slp
) == vp
)
832 vn_syncer_add(vp
, -(i
+ syncdelay
));
834 i
= (i
+ 1) & ctx
->syncer_mask
;
837 if ((vmsc_flags
& VMSC_NOWAIT
) == 0)
838 --ctx
->syncer_forced
;
839 lwkt_reltoken(&ctx
->sc_token
);
844 * Print out a syncer vnode.
846 * sync_print { struct vnode *a_vp }
849 sync_print(struct vop_print_args
*ap
)
851 struct vnode
*vp
= ap
->a_vp
;
853 kprintf("syncer vnode");
854 lockmgr_printinfo(&vp
->v_lock
);