1/*	$NetBSD: lfs_subr.c,v 1.103 2020/09/05 16:30:13 riastradh Exp $	*/
2
3/*-
4 * Copyright (c) 1999, 2000, 2001, 2002, 2003 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Konrad E. Schroder <perseant@hhhh.org>.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
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
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31/*
32 * Copyright (c) 1991, 1993
33 *	The Regents of the University of California.  All rights reserved.
34 *
35 * Redistribution and use in source and binary forms, with or without
36 * modification, are permitted provided that the following conditions
37 * are met:
38 * 1. Redistributions of source code must retain the above copyright
39 *    notice, this list of conditions and the following disclaimer.
40 * 2. Redistributions in binary form must reproduce the above copyright
41 *    notice, this list of conditions and the following disclaimer in the
42 *    documentation and/or other materials provided with the distribution.
43 * 3. Neither the name of the University nor the names of its contributors
44 *    may be used to endorse or promote products derived from this software
45 *    without specific prior written permission.
46 *
47 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
48 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
49 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
50 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
51 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
52 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
53 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
54 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
55 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
56 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
57 * SUCH DAMAGE.
58 *
59 *	@(#)lfs_subr.c	8.4 (Berkeley) 5/8/95
60 */
61
62#include <sys/cdefs.h>
63__KERNEL_RCSID(0, "$NetBSD: lfs_subr.c,v 1.103 2020/09/05 16:30:13 riastradh Exp $");
64
65#include <sys/param.h>
66#include <sys/systm.h>
67#include <sys/namei.h>
68#include <sys/vnode.h>
69#include <sys/buf.h>
70#include <sys/mount.h>
71#include <sys/malloc.h>
72#include <sys/proc.h>
73#include <sys/kauth.h>
74
75#include <ufs/lfs/ulfs_inode.h>
76#include <ufs/lfs/lfs.h>
77#include <ufs/lfs/lfs_accessors.h>
78#include <ufs/lfs/lfs_kernel.h>
79#include <ufs/lfs/lfs_extern.h>
80
81#ifdef DEBUG
82const char *lfs_res_names[LFS_NB_COUNT] = {
83	"summary",
84	"superblock",
85	"file block",
86	"cluster",
87	"clean",
88	"blkiov",
89};
90#endif
91
92int lfs_res_qty[LFS_NB_COUNT] = {
93	LFS_N_SUMMARIES,
94	LFS_N_SBLOCKS,
95	LFS_N_IBLOCKS,
96	LFS_N_CLUSTERS,
97	LFS_N_CLEAN,
98	LFS_N_BLKIOV,
99};
100
101void
102lfs_setup_resblks(struct lfs *fs)
103{
104	int i, j;
105	int maxbpp;
106
107	ASSERT_NO_SEGLOCK(fs);
108	fs->lfs_resblk = malloc(LFS_N_TOTAL * sizeof(res_t), M_SEGMENT,
109				M_WAITOK);
110	for (i = 0; i < LFS_N_TOTAL; i++) {
111		fs->lfs_resblk[i].inuse = 0;
112		fs->lfs_resblk[i].p = NULL;
113	}
114	for (i = 0; i < LFS_RESHASH_WIDTH; i++)
115		LIST_INIT(fs->lfs_reshash + i);
116
117	/*
118	 * These types of allocations can be larger than a page,
119	 * so we can't use the pool subsystem for them.
120	 */
121	for (i = 0, j = 0; j < LFS_N_SUMMARIES; j++, i++)
122		fs->lfs_resblk[i].size = lfs_sb_getsumsize(fs);
123	for (j = 0; j < LFS_N_SBLOCKS; j++, i++)
124		fs->lfs_resblk[i].size = LFS_SBPAD;
125	for (j = 0; j < LFS_N_IBLOCKS; j++, i++)
126		fs->lfs_resblk[i].size = lfs_sb_getbsize(fs);
127	for (j = 0; j < LFS_N_CLUSTERS; j++, i++)
128		fs->lfs_resblk[i].size = MAXPHYS;
129	for (j = 0; j < LFS_N_CLEAN; j++, i++)
130		fs->lfs_resblk[i].size = MAXPHYS;
131	for (j = 0; j < LFS_N_BLKIOV; j++, i++)
132		fs->lfs_resblk[i].size = LFS_MARKV_MAXBLKCNT * sizeof(BLOCK_INFO);
133
134	for (i = 0; i < LFS_N_TOTAL; i++) {
135		fs->lfs_resblk[i].p = malloc(fs->lfs_resblk[i].size,
136					     M_SEGMENT, M_WAITOK);
137	}
138
139	/*
140	 * Initialize pools for small types (XXX is BPP small?)
141	 */
142	pool_init(&fs->lfs_clpool, sizeof(struct lfs_cluster), 0, 0, 0,
143		"lfsclpl", &pool_allocator_nointr, IPL_NONE);
144	pool_init(&fs->lfs_segpool, sizeof(struct segment), 0, 0, 0,
145		"lfssegpool", &pool_allocator_nointr, IPL_NONE);
146	/* XXX: should this int32 be 32/64? */
147	maxbpp = ((lfs_sb_getsumsize(fs) - SEGSUM_SIZE(fs)) / sizeof(int32_t) + 2);
148	maxbpp = MIN(maxbpp, lfs_segsize(fs) / lfs_sb_getfsize(fs) + 2);
149	pool_init(&fs->lfs_bpppool, maxbpp * sizeof(struct buf *), 0, 0, 0,
150		"lfsbpppl", &pool_allocator_nointr, IPL_NONE);
151}
152
153void
154lfs_free_resblks(struct lfs *fs)
155{
156	int i;
157
158	pool_destroy(&fs->lfs_bpppool);
159	pool_destroy(&fs->lfs_segpool);
160	pool_destroy(&fs->lfs_clpool);
161
162	mutex_enter(&lfs_lock);
163	for (i = 0; i < LFS_N_TOTAL; i++) {
164		while (fs->lfs_resblk[i].inuse)
165			mtsleep(&fs->lfs_resblk, PRIBIO + 1, "lfs_free", 0,
166				&lfs_lock);
167		if (fs->lfs_resblk[i].p != NULL)
168			free(fs->lfs_resblk[i].p, M_SEGMENT);
169	}
170	free(fs->lfs_resblk, M_SEGMENT);
171	mutex_exit(&lfs_lock);
172}
173
174static unsigned int
175lfs_mhash(void *vp)
176{
177	return (unsigned int)(((unsigned long)vp) >> 2) % LFS_RESHASH_WIDTH;
178}
179
180/*
181 * Return memory of the given size for the given purpose, or use one of a
182 * number of spare last-resort buffers, if malloc returns NULL.
183 */
184void *
185lfs_malloc(struct lfs *fs, size_t size, int type)
186{
187	struct lfs_res_blk *re;
188	void *r;
189	int i, start;
190	unsigned int h;
191
192	ASSERT_MAYBE_SEGLOCK(fs);
193	r = NULL;
194
195	/* If no mem allocated for this type, it just waits */
196	if (lfs_res_qty[type] == 0) {
197		r = malloc(size, M_SEGMENT, M_WAITOK);
198		return r;
199	}
200
201	/* Otherwise try a quick malloc, and if it works, great */
202	if ((r = malloc(size, M_SEGMENT, M_NOWAIT)) != NULL) {
203		return r;
204	}
205
206	/*
207	 * If malloc returned NULL, we are forced to use one of our
208	 * reserve blocks.  We have on hand at least one summary block,
209	 * at least one cluster block, at least one superblock,
210	 * and several indirect blocks.
211	 */
212
213	mutex_enter(&lfs_lock);
214	/* skip over blocks of other types */
215	for (i = 0, start = 0; i < type; i++)
216		start += lfs_res_qty[i];
217	while (r == NULL) {
218		for (i = 0; i < lfs_res_qty[type]; i++) {
219			if (fs->lfs_resblk[start + i].inuse == 0) {
220				re = fs->lfs_resblk + start + i;
221				re->inuse = 1;
222				r = re->p;
223				KASSERT(re->size >= size);
224				h = lfs_mhash(r);
225				LIST_INSERT_HEAD(&fs->lfs_reshash[h], re, res);
226				mutex_exit(&lfs_lock);
227				return r;
228			}
229		}
230		DLOG((DLOG_MALLOC, "sleeping on %s (%d)\n",
231		      lfs_res_names[type], lfs_res_qty[type]));
232		mtsleep(&fs->lfs_resblk, PVM, "lfs_malloc", 0,
233			&lfs_lock);
234		DLOG((DLOG_MALLOC, "done sleeping on %s\n",
235		      lfs_res_names[type]));
236	}
237	/* NOTREACHED */
238	mutex_exit(&lfs_lock);
239	return r;
240}
241
242void
243lfs_free(struct lfs *fs, void *p, int type)
244{
245	unsigned int h;
246	res_t *re;
247
248	ASSERT_MAYBE_SEGLOCK(fs);
249	h = lfs_mhash(p);
250	mutex_enter(&lfs_lock);
251	LIST_FOREACH(re, &fs->lfs_reshash[h], res) {
252		if (re->p == p) {
253			KASSERT(re->inuse == 1);
254			LIST_REMOVE(re, res);
255			re->inuse = 0;
256			wakeup(&fs->lfs_resblk);
257			mutex_exit(&lfs_lock);
258			return;
259		}
260	}
261
262#ifdef notyet /* XXX this assert fires */
263	for (int i = 0; i < LFS_N_TOTAL; i++) {
264		KDASSERTMSG(fs->lfs_resblk[i].p == p,
265		    "lfs_free: inconsistent reserved block");
266	}
267#endif
268
269	mutex_exit(&lfs_lock);
270
271	/*
272	 * If we didn't find it, free it.
273	 */
274	free(p, M_SEGMENT);
275}
276
277/*
278 * lfs_seglock --
279 *	Single thread the segment writer.
280 */
281int
282lfs_seglock(struct lfs *fs, unsigned long flags)
283{
284	struct segment *sp;
285
286	mutex_enter(&lfs_lock);
287	if (fs->lfs_seglock) {
288		if (fs->lfs_lockpid == curproc->p_pid &&
289		    fs->lfs_locklwp == curlwp->l_lid) {
290			++fs->lfs_seglock;
291			fs->lfs_sp->seg_flags |= flags;
292			mutex_exit(&lfs_lock);
293			return 0;
294		} else if (flags & SEGM_PAGEDAEMON) {
295			mutex_exit(&lfs_lock);
296			return EWOULDBLOCK;
297		} else {
298			while (fs->lfs_seglock) {
299				(void)mtsleep(&fs->lfs_seglock, PRIBIO + 1,
300					"lfs_seglock", 0, &lfs_lock);
301			}
302		}
303	}
304
305	fs->lfs_seglock = 1;
306	fs->lfs_lockpid = curproc->p_pid;
307	fs->lfs_locklwp = curlwp->l_lid;
308	mutex_exit(&lfs_lock);
309	fs->lfs_cleanind = 0;
310
311	LFS_ENTER_LOG("seglock", __FILE__, __LINE__, 0, flags, curproc->p_pid);
312
313	/* Drain fragment size changes out */
314	rw_enter(&fs->lfs_fraglock, RW_WRITER);
315
316	sp = fs->lfs_sp = pool_get(&fs->lfs_segpool, PR_WAITOK);
317	sp->bpp = pool_get(&fs->lfs_bpppool, PR_WAITOK);
318	sp->seg_flags = flags;
319	sp->vp = NULL;
320	sp->seg_iocount = 0;
321	(void) lfs_initseg(fs);
322
323	/*
324	 * Keep a cumulative count of the outstanding I/O operations.  If the
325	 * disk drive catches up with us it could go to zero before we finish,
326	 * so we artificially increment it by one until we've scheduled all of
327	 * the writes we intend to do.
328	 */
329	mutex_enter(&lfs_lock);
330	++fs->lfs_iocount;
331	fs->lfs_startseg = lfs_sb_getcurseg(fs);
332	mutex_exit(&lfs_lock);
333	return 0;
334}
335
336static void lfs_unmark_dirop(struct lfs *);
337
338static void
339lfs_unmark_dirop(struct lfs *fs)
340{
341	struct inode *ip, *marker;
342	struct vnode *vp;
343	int doit;
344
345	ASSERT_NO_SEGLOCK(fs);
346	mutex_enter(&lfs_lock);
347	doit = !(fs->lfs_flags & LFS_UNDIROP);
348	if (doit)
349		fs->lfs_flags |= LFS_UNDIROP;
350	mutex_exit(&lfs_lock);
351
352	if (!doit)
353		return;
354
355	marker = pool_get(&lfs_inode_pool, PR_WAITOK);
356	KASSERT(fs != NULL);
357	memset(marker, 0, sizeof(*marker));
358	marker->inode_ext.lfs = pool_get(&lfs_inoext_pool, PR_WAITOK);
359	memset(marker->inode_ext.lfs, 0, sizeof(*marker->inode_ext.lfs));
360	marker->i_state |= IN_MARKER;
361
362	mutex_enter(&lfs_lock);
363	TAILQ_INSERT_HEAD(&fs->lfs_dchainhd, marker, i_lfs_dchain);
364	while ((ip = TAILQ_NEXT(marker, i_lfs_dchain)) != NULL) {
365		TAILQ_REMOVE(&fs->lfs_dchainhd, marker, i_lfs_dchain);
366		TAILQ_INSERT_AFTER(&fs->lfs_dchainhd, ip, marker,
367		    i_lfs_dchain);
368		if (ip->i_state & IN_MARKER)
369			continue;
370		vp = ITOV(ip);
371		if ((ip->i_state & (IN_ADIROP | IN_CDIROP)) == IN_CDIROP) {
372			--lfs_dirvcount;
373			--fs->lfs_dirvcount;
374			vp->v_uflag &= ~VU_DIROP;
375			TAILQ_REMOVE(&fs->lfs_dchainhd, ip, i_lfs_dchain);
376			wakeup(&lfs_dirvcount);
377			fs->lfs_unlockvp = vp;
378			mutex_exit(&lfs_lock);
379			vrele(vp);
380			mutex_enter(&lfs_lock);
381			fs->lfs_unlockvp = NULL;
382			ip->i_state &= ~IN_CDIROP;
383		}
384	}
385	TAILQ_REMOVE(&fs->lfs_dchainhd, marker, i_lfs_dchain);
386	fs->lfs_flags &= ~LFS_UNDIROP;
387	wakeup(&fs->lfs_flags);
388	mutex_exit(&lfs_lock);
389
390	pool_put(&lfs_inoext_pool, marker->inode_ext.lfs);
391	pool_put(&lfs_inode_pool, marker);
392}
393
394static void
395lfs_auto_segclean(struct lfs *fs)
396{
397	int i, error, waited;
398
399	ASSERT_SEGLOCK(fs);
400	/*
401	 * Now that we've swapped lfs_activesb, but while we still
402	 * hold the segment lock, run through the segment list marking
403	 * the empty ones clean.
404	 * XXX - do we really need to do them all at once?
405	 */
406	waited = 0;
407	for (i = 0; i < lfs_sb_getnseg(fs); i++) {
408		if ((fs->lfs_suflags[0][i] &
409		     (SEGUSE_ACTIVE | SEGUSE_DIRTY | SEGUSE_EMPTY)) ==
410		    (SEGUSE_DIRTY | SEGUSE_EMPTY) &&
411		    (fs->lfs_suflags[1][i] &
412		     (SEGUSE_ACTIVE | SEGUSE_DIRTY | SEGUSE_EMPTY)) ==
413		    (SEGUSE_DIRTY | SEGUSE_EMPTY)) {
414
415			/* Make sure the sb is written before we clean */
416			mutex_enter(&lfs_lock);
417			while (waited == 0 && fs->lfs_sbactive)
418				mtsleep(&fs->lfs_sbactive, PRIBIO+1, "lfs asb",
419					0, &lfs_lock);
420			mutex_exit(&lfs_lock);
421			waited = 1;
422
423			if ((error = lfs_do_segclean(fs, i)) != 0) {
424				DLOG((DLOG_CLEAN, "lfs_auto_segclean: lfs_do_segclean returned %d for seg %d\n", error, i));
425			}
426		}
427		fs->lfs_suflags[1 - fs->lfs_activesb][i] =
428			fs->lfs_suflags[fs->lfs_activesb][i];
429	}
430}
431
432/*
433 * lfs_segunlock --
434 *	Single thread the segment writer.
435 */
436void
437lfs_segunlock(struct lfs *fs)
438{
439	struct segment *sp;
440	unsigned long sync, ckp;
441	struct buf *bp;
442	int do_unmark_dirop = 0;
443
444	sp = fs->lfs_sp;
445
446	mutex_enter(&lfs_lock);
447
448	if (!LFS_SEGLOCK_HELD(fs))
449		panic("lfs seglock not held");
450
451	if (fs->lfs_seglock == 1) {
452		if ((sp->seg_flags & (SEGM_PROT | SEGM_CLEAN)) == 0)
453			do_unmark_dirop = 1;
454		mutex_exit(&lfs_lock);
455		sync = sp->seg_flags & SEGM_SYNC;
456		ckp = sp->seg_flags & SEGM_CKP;
457
458		/* We should have a segment summary, and nothing else */
459		KASSERT(sp->cbpp == sp->bpp + 1);
460
461		/* Free allocated segment summary */
462		lfs_sb_suboffset(fs, lfs_btofsb(fs, lfs_sb_getsumsize(fs)));
463		bp = *sp->bpp;
464		lfs_freebuf(fs, bp);
465
466		pool_put(&fs->lfs_bpppool, sp->bpp);
467		sp->bpp = NULL;
468
469		/*
470		 * If we're not sync, we're done with sp, get rid of it.
471		 * Otherwise, we keep a local copy around but free
472		 * fs->lfs_sp so another process can use it (we have to
473		 * wait but they don't have to wait for us).
474		 */
475		if (!sync)
476			pool_put(&fs->lfs_segpool, sp);
477		fs->lfs_sp = NULL;
478
479		/*
480		 * If the I/O count is non-zero, sleep until it reaches zero.
481		 * At the moment, the user's process hangs around so we can
482		 * sleep.
483		 */
484		mutex_enter(&lfs_lock);
485		if (--fs->lfs_iocount <= 1)
486			wakeup(&fs->lfs_iocount);
487		mutex_exit(&lfs_lock);
488
489		/*
490		 * If we're not checkpointing, we don't have to block
491		 * other processes to wait for a synchronous write
492		 * to complete.
493		 */
494		if (!ckp) {
495			LFS_ENTER_LOG("segunlock_std", __FILE__, __LINE__, 0, 0, curproc->p_pid);
496
497			mutex_enter(&lfs_lock);
498			--fs->lfs_seglock;
499			fs->lfs_lockpid = 0;
500			fs->lfs_locklwp = 0;
501			mutex_exit(&lfs_lock);
502			wakeup(&fs->lfs_seglock);
503		}
504		/*
505		 * We let checkpoints happen asynchronously.  That means
506		 * that during recovery, we have to roll forward between
507		 * the two segments described by the first and second
508		 * superblocks to make sure that the checkpoint described
509		 * by a superblock completed.
510		 */
511		mutex_enter(&lfs_lock);
512		while (ckp && sync && fs->lfs_iocount) {
513			(void)mtsleep(&fs->lfs_iocount, PRIBIO + 1,
514				      "lfs_iocount", 0, &lfs_lock);
515			DLOG((DLOG_SEG, "sleeping on iocount %x == %d\n", fs, fs->lfs_iocount));
516		}
517		while (sync && sp->seg_iocount) {
518			(void)mtsleep(&sp->seg_iocount, PRIBIO + 1,
519				     "seg_iocount", 0, &lfs_lock);
520			DLOG((DLOG_SEG, "sleeping on iocount %x == %d\n", sp, sp->seg_iocount));
521		}
522		mutex_exit(&lfs_lock);
523		if (sync)
524			pool_put(&fs->lfs_segpool, sp);
525
526		if (ckp) {
527			fs->lfs_nactive = 0;
528			/* If we *know* everything's on disk, write both sbs */
529			/* XXX should wait for this one	 */
530			if (sync)
531				lfs_writesuper(fs, lfs_sb_getsboff(fs, fs->lfs_activesb));
532			lfs_writesuper(fs, lfs_sb_getsboff(fs, 1 - fs->lfs_activesb));
533			if (!(fs->lfs_ivnode->v_mount->mnt_iflag & IMNT_UNMOUNT)) {
534				lfs_auto_segclean(fs);
535				/* If sync, we can clean the remainder too */
536				if (sync)
537					lfs_auto_segclean(fs);
538			}
539			fs->lfs_activesb = 1 - fs->lfs_activesb;
540
541			LFS_ENTER_LOG("segunlock_ckp", __FILE__, __LINE__, 0, 0, curproc->p_pid);
542
543			mutex_enter(&lfs_lock);
544			--fs->lfs_seglock;
545			fs->lfs_lockpid = 0;
546			fs->lfs_locklwp = 0;
547			mutex_exit(&lfs_lock);
548			wakeup(&fs->lfs_seglock);
549		}
550		/* Reenable fragment size changes */
551		rw_exit(&fs->lfs_fraglock);
552		if (do_unmark_dirop)
553			lfs_unmark_dirop(fs);
554	} else {
555		--fs->lfs_seglock;
556		KASSERT(fs->lfs_seglock != 0);
557		mutex_exit(&lfs_lock);
558	}
559}
560
561/*
562 * Drain dirops and start writer.
563 *
564 * No simple_locks are held when we enter and none are held when we return.
565 */
566void
567lfs_writer_enter(struct lfs *fs, const char *wmesg)
568{
569	int error __diagused;
570
571	ASSERT_NO_SEGLOCK(fs);
572	mutex_enter(&lfs_lock);
573
574	/* disallow dirops during flush */
575	fs->lfs_writer++;
576
577	while (fs->lfs_dirops > 0) {
578		++fs->lfs_diropwait;
579		error = mtsleep(&fs->lfs_writer, PRIBIO+1, wmesg, 0,
580				&lfs_lock);
581		KASSERT(error == 0);
582		--fs->lfs_diropwait;
583	}
584
585	mutex_exit(&lfs_lock);
586}
587
588int
589lfs_writer_tryenter(struct lfs *fs)
590{
591	int writer_set;
592
593	ASSERT_MAYBE_SEGLOCK(fs);
594	mutex_enter(&lfs_lock);
595	writer_set = (fs->lfs_dirops == 0);
596	if (writer_set)
597		fs->lfs_writer++;
598	mutex_exit(&lfs_lock);
599
600	return writer_set;
601}
602
603void
604lfs_writer_leave(struct lfs *fs)
605{
606	bool dowakeup;
607
608	ASSERT_MAYBE_SEGLOCK(fs);
609	mutex_enter(&lfs_lock);
610	dowakeup = !(--fs->lfs_writer);
611	if (dowakeup)
612		cv_broadcast(&fs->lfs_diropscv);
613	mutex_exit(&lfs_lock);
614}
615
616/*
617 * Unlock, wait for the cleaner, then relock to where we were before.
618 * To be used only at a fairly high level, to address a paucity of free
619 * segments propagated back from lfs_gop_write().
620 */
621void
622lfs_segunlock_relock(struct lfs *fs)
623{
624	int n = fs->lfs_seglock;
625	u_int16_t seg_flags;
626	CLEANERINFO *cip;
627	struct buf *bp;
628
629	if (n == 0)
630		return;
631
632	/* Write anything we've already gathered to disk */
633	lfs_writeseg(fs, fs->lfs_sp);
634
635	/* Tell cleaner */
636	LFS_CLEANERINFO(cip, fs, bp);
637	lfs_ci_setflags(fs, cip,
638			lfs_ci_getflags(fs, cip) | LFS_CLEANER_MUST_CLEAN);
639	LFS_SYNC_CLEANERINFO(cip, fs, bp, 1);
640
641	/* Save segment flags for later */
642	seg_flags = fs->lfs_sp->seg_flags;
643
644	fs->lfs_sp->seg_flags |= SEGM_PROT; /* Don't unmark dirop nodes */
645	while(fs->lfs_seglock)
646		lfs_segunlock(fs);
647
648	/* Wait for the cleaner */
649	lfs_wakeup_cleaner(fs);
650	mutex_enter(&lfs_lock);
651	while (LFS_STARVED_FOR_SEGS(fs))
652		mtsleep(&fs->lfs_availsleep, PRIBIO, "relock", 0,
653			&lfs_lock);
654	mutex_exit(&lfs_lock);
655
656	/* Put the segment lock back the way it was. */
657	while(n--)
658		lfs_seglock(fs, seg_flags);
659
660	/* Cleaner can relax now */
661	LFS_CLEANERINFO(cip, fs, bp);
662	lfs_ci_setflags(fs, cip,
663			lfs_ci_getflags(fs, cip) & ~LFS_CLEANER_MUST_CLEAN);
664	LFS_SYNC_CLEANERINFO(cip, fs, bp, 1);
665
666	return;
667}
668
669/*
670 * Wake up the cleaner, provided that nowrap is not set.
671 */
672void
673lfs_wakeup_cleaner(struct lfs *fs)
674{
675	if (fs->lfs_nowrap > 0)
676		return;
677
678	cv_broadcast(&fs->lfs_nextsegsleep);
679	cv_broadcast(&lfs_allclean_wakeup);
680}
681