xref: /netbsd-src/sys/ufs/lfs/lfs_segment.c (revision 95d875fb90b1458e4f1de6950286ddcd6644bc61)
1 /*	$NetBSD: lfs_segment.c,v 1.37 1999/12/03 21:47:44 perseant Exp $	*/
2 
3 /*-
4  * Copyright (c) 1999 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  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *      This product includes software developed by the NetBSD
21  *      Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 /*
39  * Copyright (c) 1991, 1993
40  *	The Regents of the University of California.  All rights reserved.
41  *
42  * Redistribution and use in source and binary forms, with or without
43  * modification, are permitted provided that the following conditions
44  * are met:
45  * 1. Redistributions of source code must retain the above copyright
46  *    notice, this list of conditions and the following disclaimer.
47  * 2. Redistributions in binary form must reproduce the above copyright
48  *    notice, this list of conditions and the following disclaimer in the
49  *    documentation and/or other materials provided with the distribution.
50  * 3. All advertising materials mentioning features or use of this software
51  *    must display the following acknowledgement:
52  *	This product includes software developed by the University of
53  *	California, Berkeley and its contributors.
54  * 4. Neither the name of the University nor the names of its contributors
55  *    may be used to endorse or promote products derived from this software
56  *    without specific prior written permission.
57  *
58  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
59  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
60  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
61  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
62  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
63  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
64  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
65  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
66  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
67  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
68  * SUCH DAMAGE.
69  *
70  *	@(#)lfs_segment.c	8.10 (Berkeley) 6/10/95
71  */
72 
73 #define ivndebug(vp,str) printf("ino %d: %s\n",VTOI(vp)->i_number,(str))
74 
75 #include "opt_ddb.h"
76 #include <sys/param.h>
77 #include <sys/systm.h>
78 #include <sys/namei.h>
79 #include <sys/kernel.h>
80 #include <sys/resourcevar.h>
81 #include <sys/file.h>
82 #include <sys/stat.h>
83 #include <sys/buf.h>
84 #include <sys/proc.h>
85 #include <sys/conf.h>
86 #include <sys/vnode.h>
87 #include <sys/malloc.h>
88 #include <sys/mount.h>
89 
90 #include <miscfs/specfs/specdev.h>
91 #include <miscfs/fifofs/fifo.h>
92 
93 #include <ufs/ufs/quota.h>
94 #include <ufs/ufs/inode.h>
95 #include <ufs/ufs/dir.h>
96 #include <ufs/ufs/ufsmount.h>
97 #include <ufs/ufs/ufs_extern.h>
98 
99 #include <ufs/lfs/lfs.h>
100 #include <ufs/lfs/lfs_extern.h>
101 
102 extern int count_lock_queue __P((void));
103 extern struct simplelock vnode_free_list_slock;		/* XXX */
104 
105 /*
106  * Determine if it's OK to start a partial in this segment, or if we need
107  * to go on to a new segment.
108  */
109 #define	LFS_PARTIAL_FITS(fs) \
110 	((fs)->lfs_dbpseg - ((fs)->lfs_offset - (fs)->lfs_curseg) > \
111 	1 << (fs)->lfs_fsbtodb)
112 
113 void	 lfs_callback __P((struct buf *));
114 int	 lfs_gather __P((struct lfs *, struct segment *,
115 	     struct vnode *, int (*) __P((struct lfs *, struct buf *))));
116 int	 lfs_gatherblock __P((struct segment *, struct buf *, int *));
117 void	 lfs_iset __P((struct inode *, ufs_daddr_t, time_t));
118 int	 lfs_match_fake __P((struct lfs *, struct buf *));
119 int	 lfs_match_data __P((struct lfs *, struct buf *));
120 int	 lfs_match_dindir __P((struct lfs *, struct buf *));
121 int	 lfs_match_indir __P((struct lfs *, struct buf *));
122 int	 lfs_match_tindir __P((struct lfs *, struct buf *));
123 void	 lfs_newseg __P((struct lfs *));
124 void	 lfs_shellsort __P((struct buf **, ufs_daddr_t *, register int));
125 void	 lfs_supercallback __P((struct buf *));
126 void	 lfs_updatemeta __P((struct segment *));
127 int	 lfs_vref __P((struct vnode *));
128 void	 lfs_vunref __P((struct vnode *));
129 void	 lfs_writefile __P((struct lfs *, struct segment *, struct vnode *));
130 int	 lfs_writeinode __P((struct lfs *, struct segment *, struct inode *));
131 int	 lfs_writeseg __P((struct lfs *, struct segment *));
132 void	 lfs_writesuper __P((struct lfs *, daddr_t));
133 int	 lfs_writevnodes __P((struct lfs *fs, struct mount *mp,
134 	    struct segment *sp, int dirops));
135 
136 int	lfs_allclean_wakeup;		/* Cleaner wakeup address. */
137 int	lfs_writeindir = 1;             /* whether to flush indir on non-ckp */
138 int	lfs_clean_vnhead = 0;		/* Allow freeing to head of vn list */
139 int	lfs_dirvcount = 0;		/* # active dirops */
140 
141 /* Statistics Counters */
142 int lfs_dostats = 1;
143 struct lfs_stats lfs_stats;
144 
145 /* op values to lfs_writevnodes */
146 #define	VN_REG	        0
147 #define	VN_DIROP	1
148 #define	VN_EMPTY	2
149 #define VN_CLEAN        3
150 
151 #define LFS_MAX_ACTIVE          10
152 
153 /*
154  * XXX KS - Set modification time on the Ifile, so the cleaner can
155  * read the fs mod time off of it.  We don't set IN_UPDATE here,
156  * since we don't really need this to be flushed to disk (and in any
157  * case that wouldn't happen to the Ifile until we checkpoint).
158  */
159 void
160 lfs_imtime(fs)
161 	struct lfs *fs;
162 {
163 	struct timespec ts;
164 	struct inode *ip;
165 
166 	TIMEVAL_TO_TIMESPEC(&time, &ts);
167 	ip = VTOI(fs->lfs_ivnode);
168 	ip->i_ffs_mtime = ts.tv_sec;
169 	ip->i_ffs_mtimensec = ts.tv_nsec;
170 }
171 
172 /*
173  * Ifile and meta data blocks are not marked busy, so segment writes MUST be
174  * single threaded.  Currently, there are two paths into lfs_segwrite, sync()
175  * and getnewbuf().  They both mark the file system busy.  Lfs_vflush()
176  * explicitly marks the file system busy.  So lfs_segwrite is safe.  I think.
177  */
178 
179 #define SET_FLUSHING(fs,vp) (fs)->lfs_flushvp = (vp)
180 #define IS_FLUSHING(fs,vp)  ((fs)->lfs_flushvp == (vp))
181 #define CLR_FLUSHING(fs,vp) (fs)->lfs_flushvp = NULL
182 
183 int
184 lfs_vflush(vp)
185 	struct vnode *vp;
186 {
187 	struct inode *ip;
188 	struct lfs *fs;
189 	struct segment *sp;
190 	struct buf *bp, *nbp;
191 	int error, s;
192 
193 	ip = VTOI(vp);
194 	fs = VFSTOUFS(vp->v_mount)->um_lfs;
195 
196 	if(ip->i_flag & IN_CLEANING) {
197 #ifdef DEBUG_LFS
198 		ivndebug(vp,"vflush/in_cleaning");
199 #endif
200 		ip->i_flag &= ~IN_CLEANING;
201 		if(ip->i_flag & IN_MODIFIED) {
202 			fs->lfs_uinodes--;
203 		} else
204 			ip->i_flag |= IN_MODIFIED;
205 	}
206 
207 	/* If the node is being written, wait until that is done */
208 	if(WRITEINPROG(vp)) {
209 #ifdef DEBUG_LFS
210 		ivndebug(vp,"vflush/writeinprog");
211 #endif
212 		tsleep(vp, PRIBIO+1, "lfs_vw", 0);
213 	}
214 
215 	/* Protect against VXLOCK deadlock in vinvalbuf() */
216 	lfs_seglock(fs, SEGM_SYNC);
217 
218 	/* If we're supposed to flush a freed inode, just toss it */
219 	/* XXX - seglock, so these buffers can't be gathered, right? */
220 	if(ip->i_ffs_mode == 0) {
221 		printf("lfs_vflush: ino %d is freed, not flushing\n",
222 			ip->i_number);
223 		s = splbio();
224 		for(bp=vp->v_dirtyblkhd.lh_first; bp; bp=nbp) {
225 			nbp = bp->b_vnbufs.le_next;
226 			/* Copied from lfs_writeseg */
227 			if (bp->b_flags & B_CALL) {
228 				/* if B_CALL, it was created with newbuf */
229 				lfs_freebuf(bp);
230 			} else {
231 				bremfree(bp);
232 				bp->b_flags &= ~(B_ERROR | B_READ | B_DELWRI |
233                                          B_LOCKED | B_GATHERED);
234 				bp->b_flags |= B_DONE;
235 				reassignbuf(bp, vp);
236 				brelse(bp);
237 			}
238 		}
239 		splx(s);
240 		if(ip->i_flag & IN_CLEANING)
241 			fs->lfs_uinodes--;
242 		if(ip->i_flag & IN_MODIFIED)
243 			fs->lfs_uinodes--;
244 		ip->i_flag &= ~(IN_MODIFIED|IN_UPDATE|IN_ACCESS|IN_CHANGE|IN_CLEANING);
245 		printf("lfs_vflush: done not flushing ino %d\n",
246 			ip->i_number);
247 		lfs_segunlock(fs);
248 		return 0;
249 	}
250 
251 	SET_FLUSHING(fs,vp);
252 	if (fs->lfs_nactive > LFS_MAX_ACTIVE) {
253 		error = lfs_segwrite(vp->v_mount, SEGM_SYNC|SEGM_CKP);
254 		CLR_FLUSHING(fs,vp);
255 		lfs_segunlock(fs);
256 		return error;
257 	}
258 	sp = fs->lfs_sp;
259 
260 	if (vp->v_dirtyblkhd.lh_first == NULL) {
261 		lfs_writevnodes(fs, vp->v_mount, sp, VN_EMPTY);
262 	} else if((ip->i_flag & IN_CLEANING) && (fs->lfs_sp->seg_flags & SEGM_CLEAN)) {
263 #ifdef DEBUG_LFS
264 		ivndebug(vp,"vflush/clean");
265 #endif
266 		lfs_writevnodes(fs, vp->v_mount, sp, VN_CLEAN);
267 	}
268 	else if(lfs_dostats) {
269 		if(vp->v_dirtyblkhd.lh_first || (VTOI(vp)->i_flag & (IN_MODIFIED|IN_UPDATE|IN_ACCESS|IN_CHANGE|IN_CLEANING)))
270 			++lfs_stats.vflush_invoked;
271 #ifdef DEBUG_LFS
272 		ivndebug(vp,"vflush");
273 #endif
274 	}
275 
276 #ifdef DIAGNOSTIC
277 	/* XXX KS This actually can happen right now, though it shouldn't(?) */
278 	if(vp->v_flag & VDIROP) {
279 		printf("lfs_vflush: flushing VDIROP, this shouldn\'t be\n");
280 		/* panic("VDIROP being flushed...this can\'t happen"); */
281 	}
282 	if(vp->v_usecount<0) {
283 		printf("usecount=%ld\n",vp->v_usecount);
284 		panic("lfs_vflush: usecount<0");
285 	}
286 #endif
287 
288 	do {
289 		do {
290 			if (vp->v_dirtyblkhd.lh_first != NULL)
291 				lfs_writefile(fs, sp, vp);
292 		} while (lfs_writeinode(fs, sp, ip));
293 	} while (lfs_writeseg(fs, sp) && ip->i_number == LFS_IFILE_INUM);
294 
295 	if(lfs_dostats) {
296 		++lfs_stats.nwrites;
297 		if (sp->seg_flags & SEGM_SYNC)
298 			++lfs_stats.nsync_writes;
299 		if (sp->seg_flags & SEGM_CKP)
300 			++lfs_stats.ncheckpoints;
301 	}
302 	lfs_segunlock(fs);
303 
304 	CLR_FLUSHING(fs,vp);
305 	return (0);
306 }
307 
308 #ifdef DEBUG_LFS_VERBOSE
309 # define vndebug(vp,str) if(VTOI(vp)->i_flag & IN_CLEANING) printf("not writing ino %d because %s (op %d)\n",VTOI(vp)->i_number,(str),op)
310 #else
311 # define vndebug(vp,str)
312 #endif
313 
314 int
315 lfs_writevnodes(fs, mp, sp, op)
316 	struct lfs *fs;
317 	struct mount *mp;
318 	struct segment *sp;
319 	int op;
320 {
321 	struct inode *ip;
322 	struct vnode *vp;
323 	int inodes_written=0, only_cleaning;
324 
325 #ifndef LFS_NO_BACKVP_HACK
326 	/* BEGIN HACK */
327 #define	VN_OFFSET	(((caddr_t)&vp->v_mntvnodes.le_next) - (caddr_t)vp)
328 #define	BACK_VP(VP)	((struct vnode *)(((caddr_t)VP->v_mntvnodes.le_prev) - VN_OFFSET))
329 #define	BEG_OF_VLIST	((struct vnode *)(((caddr_t)&mp->mnt_vnodelist.lh_first) - VN_OFFSET))
330 
331 	/* Find last vnode. */
332  loop:	for (vp = mp->mnt_vnodelist.lh_first;
333 	     vp && vp->v_mntvnodes.le_next != NULL;
334 	     vp = vp->v_mntvnodes.le_next);
335 	for (; vp && vp != BEG_OF_VLIST; vp = BACK_VP(vp)) {
336 #else
337 	loop:
338 	for (vp = mp->mnt_vnodelist.lh_first;
339 	     vp != NULL;
340 	     vp = vp->v_mntvnodes.le_next) {
341 #endif
342 		/*
343 		 * If the vnode that we are about to sync is no longer
344 		 * associated with this mount point, start over.
345 		 */
346 		if (vp->v_mount != mp)
347 			goto loop;
348 
349 		ip = VTOI(vp);
350 		if ((op == VN_DIROP && !(vp->v_flag & VDIROP)) ||
351 		    (op != VN_DIROP && op != VN_CLEAN && (vp->v_flag & VDIROP))) {
352 			vndebug(vp,"dirop");
353 			continue;
354 		}
355 
356 		if (op == VN_EMPTY && vp->v_dirtyblkhd.lh_first) {
357 			vndebug(vp,"empty");
358 			continue;
359 		}
360 
361 		if (vp->v_type == VNON) {
362 			continue;
363 		}
364 
365 		if(op == VN_CLEAN && ip->i_number != LFS_IFILE_INUM
366 		   && !(ip->i_flag & IN_CLEANING)) {
367 			vndebug(vp,"cleaning");
368 			continue;
369 		}
370 
371 		if (lfs_vref(vp)) {
372 			vndebug(vp,"vref");
373 			continue;
374 		}
375 
376 #if 0 /* XXX KS - if we skip the ifile, things could go badly for us. */
377 		if(WRITEINPROG(vp)) {
378 			lfs_vunref(vp);
379 #ifdef DEBUG_LFS
380 			ivndebug(vp,"writevnodes/writeinprog");
381 #endif
382 			continue;
383 		}
384 #endif
385 		only_cleaning = 0;
386 		/*
387 		 * Write the inode/file if dirty and it's not the
388 		 * the IFILE.
389 		 */
390 		if ((ip->i_flag &
391 		     (IN_ACCESS | IN_CHANGE | IN_MODIFIED | IN_UPDATE | IN_CLEANING) ||
392 		     vp->v_dirtyblkhd.lh_first != NULL))
393 		{
394 			only_cleaning = ((ip->i_flag & (IN_ACCESS|IN_CHANGE|IN_MODIFIED|IN_UPDATE|IN_CLEANING))==IN_CLEANING);
395 
396 			if(ip->i_number != LFS_IFILE_INUM
397 			   && vp->v_dirtyblkhd.lh_first != NULL)
398 			{
399 				lfs_writefile(fs, sp, vp);
400 			}
401 			if(vp->v_dirtyblkhd.lh_first != NULL) {
402 				if(WRITEINPROG(vp)) {
403 #ifdef DEBUG_LFS
404 					ivndebug(vp,"writevnodes/write2");
405 #endif
406 				} else if(!(ip->i_flag & (IN_ACCESS|IN_CHANGE|IN_MODIFIED|IN_UPDATE|IN_CLEANING))) {
407 #ifdef DEBUG_LFS
408 					printf("<%d>",ip->i_number);
409 #endif
410 					ip->i_flag |= IN_MODIFIED;
411 					++fs->lfs_uinodes;
412 				}
413 			}
414 			(void) lfs_writeinode(fs, sp, ip);
415 			inodes_written++;
416 		}
417 
418 		if(vp->v_flag & VDIROP) {
419 			--lfs_dirvcount;
420 			vp->v_flag &= ~VDIROP;
421 			wakeup(&lfs_dirvcount);
422 			lfs_vunref(vp);
423 		}
424 
425 		if(lfs_clean_vnhead && only_cleaning)
426 			lfs_vunref_head(vp);
427 		else
428 			lfs_vunref(vp);
429 	}
430 	return inodes_written;
431 }
432 
433 int
434 lfs_segwrite(mp, flags)
435 	struct mount *mp;
436 	int flags;			/* Do a checkpoint. */
437 {
438 	struct buf *bp;
439 	struct inode *ip;
440 	struct lfs *fs;
441 	struct segment *sp;
442 	struct vnode *vp;
443 	SEGUSE *segusep;
444 	ufs_daddr_t ibno;
445 	int do_ckp, error, i;
446 	int writer_set = 0;
447 	int need_unlock = 0;
448 
449 	fs = VFSTOUFS(mp)->um_lfs;
450 
451 	lfs_imtime(fs);
452 
453 	/*
454 	 * If we are not the cleaner, and we have fewer than MIN_FREE_SEGS
455 	 * clean segments, wait until cleaner writes.
456 	 */
457 	if(!(flags & SEGM_CLEAN)
458 	   && (!fs->lfs_seglock || !(fs->lfs_sp->seg_flags & SEGM_CLEAN)))
459 	{
460 		do {
461 			if (fs->lfs_nclean <= MIN_FREE_SEGS
462 			    || fs->lfs_avail <= 0)
463 			{
464 				wakeup(&lfs_allclean_wakeup);
465 				wakeup(&fs->lfs_nextseg);
466 				error = tsleep(&fs->lfs_avail, PRIBIO + 1,
467 					       "lfs_avail", 0);
468 				if (error) {
469 					return (error);
470 				}
471 			}
472 		} while (fs->lfs_nclean <= MIN_FREE_SEGS || fs->lfs_avail <= 0);
473 	}
474 
475 	/*
476 	 * Allocate a segment structure and enough space to hold pointers to
477 	 * the maximum possible number of buffers which can be described in a
478 	 * single summary block.
479 	 */
480 	do_ckp = (flags & SEGM_CKP) || fs->lfs_nactive > LFS_MAX_ACTIVE;
481 	lfs_seglock(fs, flags | (do_ckp ? SEGM_CKP : 0));
482 	sp = fs->lfs_sp;
483 
484 	/*
485 	 * If lfs_flushvp is non-NULL, we are called from lfs_vflush,
486 	 * in which case we have to flush *all* buffers off of this vnode.
487 	 * We don't care about other nodes, but write any non-dirop nodes
488 	 * anyway in anticipation of another getnewvnode().
489 	 *
490 	 * If we're cleaning we only write cleaning and ifile blocks, and
491 	 * no dirops, since otherwise we'd risk corruption in a crash.
492 	 */
493 	if(fs->lfs_flushvp)
494 		lfs_writevnodes(fs, mp, sp, VN_REG);
495 	else if(sp->seg_flags & SEGM_CLEAN)
496 		lfs_writevnodes(fs, mp, sp, VN_CLEAN);
497 	else {
498 		lfs_writevnodes(fs, mp, sp, VN_REG);
499 		while(fs->lfs_dirops)
500 			if((error = tsleep(&fs->lfs_writer, PRIBIO + 1,
501 					"lfs writer", 0)))
502 			{
503 				free(sp->bpp, M_SEGMENT);
504 				free(sp, M_SEGMENT);
505 				return (error);
506 			}
507 		fs->lfs_writer++;
508 		writer_set=1;
509 		lfs_writevnodes(fs, mp, sp, VN_DIROP);
510 		((SEGSUM *)(sp->segsum))->ss_flags &= ~(SS_CONT);
511 	}
512 
513 	/*
514 	 * If we are doing a checkpoint, mark everything since the
515 	 * last checkpoint as no longer ACTIVE.
516 	 */
517 	if (do_ckp) {
518 		for (ibno = fs->lfs_cleansz + fs->lfs_segtabsz;
519 		     --ibno >= fs->lfs_cleansz; ) {
520 			if (bread(fs->lfs_ivnode, ibno, fs->lfs_bsize, NOCRED, &bp))
521 
522 				panic("lfs_segwrite: ifile read");
523 			segusep = (SEGUSE *)bp->b_data;
524 			for (i = fs->lfs_sepb; i--; segusep++)
525 				segusep->su_flags &= ~SEGUSE_ACTIVE;
526 
527 			/* But the current segment is still ACTIVE */
528 			if (fs->lfs_curseg/fs->lfs_sepb==(ibno-fs->lfs_cleansz))
529 				((SEGUSE *)(bp->b_data))[fs->lfs_curseg%fs->lfs_sepb].su_flags |= SEGUSE_ACTIVE;
530 			error = VOP_BWRITE(bp);
531 		}
532 	}
533 
534 	if (do_ckp || fs->lfs_doifile) {
535 	redo:
536 		vp = fs->lfs_ivnode;
537 		/*
538 		 * Depending on the circumstances of our calling, the ifile
539 		 * inode might be locked.  If it is, and if it is locked by
540 		 * us, we should VREF instead of vget here.
541 		 */
542 		need_unlock = 0;
543 		if(VOP_ISLOCKED(vp)
544 		   && vp->v_lock.lk_lockholder == curproc->p_pid) {
545 			VREF(vp);
546 		} else {
547 			while (vget(vp, LK_EXCLUSIVE))
548 				continue;
549 			need_unlock = 1;
550 		}
551 		ip = VTOI(vp);
552 		if (vp->v_dirtyblkhd.lh_first != NULL)
553 			lfs_writefile(fs, sp, vp);
554 		(void)lfs_writeinode(fs, sp, ip);
555 
556 		/* Only vput if we used vget() above. */
557 		if(need_unlock)
558 			vput(vp);
559 		else
560 			vrele(vp);
561 
562 		if (lfs_writeseg(fs, sp) && do_ckp)
563 			goto redo;
564 	} else {
565 		(void) lfs_writeseg(fs, sp);
566 	}
567 
568 	/*
569 	 * If the I/O count is non-zero, sleep until it reaches zero.
570 	 * At the moment, the user's process hangs around so we can
571 	 * sleep.
572 	 */
573 	fs->lfs_doifile = 0;
574 	if(writer_set && --fs->lfs_writer==0)
575 		wakeup(&fs->lfs_dirops);
576 
577 	if(lfs_dostats) {
578 		++lfs_stats.nwrites;
579 		if (sp->seg_flags & SEGM_SYNC)
580 			++lfs_stats.nsync_writes;
581 		if (sp->seg_flags & SEGM_CKP)
582 			++lfs_stats.ncheckpoints;
583 	}
584 	lfs_segunlock(fs);
585 	return (0);
586 }
587 
588 /*
589  * Write the dirty blocks associated with a vnode.
590  */
591 void
592 lfs_writefile(fs, sp, vp)
593 	struct lfs *fs;
594 	struct segment *sp;
595 	struct vnode *vp;
596 {
597 	struct buf *bp;
598 	struct finfo *fip;
599 	IFILE *ifp;
600 
601 
602 	if (sp->seg_bytes_left < fs->lfs_bsize ||
603 	    sp->sum_bytes_left < sizeof(struct finfo))
604 		(void) lfs_writeseg(fs, sp);
605 
606 	sp->sum_bytes_left -= sizeof(struct finfo) - sizeof(ufs_daddr_t);
607 	++((SEGSUM *)(sp->segsum))->ss_nfinfo;
608 
609 	if(vp->v_flag & VDIROP)
610 		((SEGSUM *)(sp->segsum))->ss_flags |= (SS_DIROP|SS_CONT);
611 
612 	fip = sp->fip;
613 	fip->fi_nblocks = 0;
614 	fip->fi_ino = VTOI(vp)->i_number;
615 	LFS_IENTRY(ifp, fs, fip->fi_ino, bp);
616 	fip->fi_version = ifp->if_version;
617 	brelse(bp);
618 
619 	/*
620 	 * It may not be necessary to write the meta-data blocks at this point,
621 	 * as the roll-forward recovery code should be able to reconstruct the
622 	 * list.
623 	 *
624 	 * We have to write them anyway, though, under two conditions: (1) the
625 	 * vnode is being flushed (for reuse by vinvalbuf); or (2) we are
626 	 * checkpointing.
627 	 */
628 	if((sp->seg_flags & SEGM_CLEAN)
629 	   && VTOI(vp)->i_number != LFS_IFILE_INUM
630 	   && !IS_FLUSHING(fs,vp))
631 	{
632 		lfs_gather(fs, sp, vp, lfs_match_fake);
633 	} else
634 		lfs_gather(fs, sp, vp, lfs_match_data);
635 
636 	if(lfs_writeindir
637 	   || IS_FLUSHING(fs,vp)
638 	   || (sp->seg_flags & SEGM_CKP))
639 	{
640 		lfs_gather(fs, sp, vp, lfs_match_indir);
641 		lfs_gather(fs, sp, vp, lfs_match_dindir);
642 /* XXX KS - when is TRIPLE not true? */ /* #ifdef TRIPLE */
643 		lfs_gather(fs, sp, vp, lfs_match_tindir);
644 /* #endif */
645 	}
646 	fip = sp->fip;
647 	if (fip->fi_nblocks != 0) {
648 		sp->fip = (FINFO*)((caddr_t)fip + sizeof(struct finfo) +
649 				   sizeof(ufs_daddr_t) * (fip->fi_nblocks-1));
650 		sp->start_lbp = &sp->fip->fi_blocks[0];
651 	} else {
652 		sp->sum_bytes_left += sizeof(FINFO) - sizeof(ufs_daddr_t);
653 		--((SEGSUM *)(sp->segsum))->ss_nfinfo;
654 	}
655 }
656 
657 int
658 lfs_writeinode(fs, sp, ip)
659 	struct lfs *fs;
660 	struct segment *sp;
661 	struct inode *ip;
662 {
663 	struct buf *bp, *ibp;
664 	IFILE *ifp;
665 	SEGUSE *sup;
666 	ufs_daddr_t daddr;
667 	ino_t ino;
668 	int error, i, ndx;
669 	int redo_ifile = 0;
670 	struct timespec ts;
671 	int gotblk=0;
672 
673 	if (!(ip->i_flag & (IN_ACCESS | IN_CHANGE | IN_MODIFIED | IN_UPDATE | IN_CLEANING)))
674 		return(0);
675 
676 	/* Allocate a new inode block if necessary. */
677 	if ((ip->i_number != LFS_IFILE_INUM || sp->idp==NULL) && sp->ibp == NULL) {
678 		/* Allocate a new segment if necessary. */
679 		if (sp->seg_bytes_left < fs->lfs_bsize ||
680 		    sp->sum_bytes_left < sizeof(ufs_daddr_t))
681 			(void) lfs_writeseg(fs, sp);
682 
683 		/* Get next inode block. */
684 		daddr = fs->lfs_offset;
685 		fs->lfs_offset += fsbtodb(fs, 1);
686 		sp->ibp = *sp->cbpp++ =
687 			getblk(VTOI(fs->lfs_ivnode)->i_devvp, daddr, fs->lfs_bsize, 0, 0);
688 		gotblk++;
689 
690 		/* Zero out inode numbers */
691 		for (i = 0; i < INOPB(fs); ++i)
692 			((struct dinode *)sp->ibp->b_data)[i].di_inumber = 0;
693 
694 		++sp->start_bpp;
695 		fs->lfs_avail -= fsbtodb(fs, 1);
696 		/* Set remaining space counters. */
697 		sp->seg_bytes_left -= fs->lfs_bsize;
698 		sp->sum_bytes_left -= sizeof(ufs_daddr_t);
699 		ndx = LFS_SUMMARY_SIZE / sizeof(ufs_daddr_t) -
700 			sp->ninodes / INOPB(fs) - 1;
701 		((ufs_daddr_t *)(sp->segsum))[ndx] = daddr;
702 	}
703 
704 	/* Update the inode times and copy the inode onto the inode page. */
705 	if (ip->i_flag & (IN_CLEANING|IN_MODIFIED))
706 		--fs->lfs_uinodes;
707 	TIMEVAL_TO_TIMESPEC(&time, &ts);
708 	LFS_ITIMES(ip, &ts, &ts, &ts);
709 
710 	if(ip->i_flag & IN_CLEANING)
711 		ip->i_flag &= ~IN_CLEANING;
712 	else
713 		ip->i_flag &= ~(IN_ACCESS|IN_CHANGE|IN_MODIFIED|IN_UPDATE);
714 
715 	/*
716 	 * If this is the Ifile, and we've already written the Ifile in this
717 	 * partial segment, just overwrite it (it's not on disk yet) and
718 	 * continue.
719 	 *
720 	 * XXX we know that the bp that we get the second time around has
721 	 * already been gathered.
722 	 */
723 	if(ip->i_number == LFS_IFILE_INUM && sp->idp) {
724 		*(sp->idp) = ip->i_din.ffs_din;
725 		return 0;
726 	}
727 
728 	bp = sp->ibp;
729 	((struct dinode *)bp->b_data)[sp->ninodes % INOPB(fs)] =
730 		ip->i_din.ffs_din;
731 
732 	if(ip->i_number == LFS_IFILE_INUM) /* We know sp->idp == NULL */
733 		sp->idp = ((struct dinode *)bp->b_data)+(sp->ninodes % INOPB(fs));
734 	if(gotblk) {
735 		bp->b_flags |= B_LOCKED;
736 		brelse(bp);
737 	}
738 
739 	/* Increment inode count in segment summary block. */
740 	++((SEGSUM *)(sp->segsum))->ss_ninos;
741 
742 	/* If this page is full, set flag to allocate a new page. */
743 	if (++sp->ninodes % INOPB(fs) == 0)
744 		sp->ibp = NULL;
745 
746 	/*
747 	 * If updating the ifile, update the super-block.  Update the disk
748 	 * address and access times for this inode in the ifile.
749 	 */
750 	ino = ip->i_number;
751 	if (ino == LFS_IFILE_INUM) {
752 		daddr = fs->lfs_idaddr;
753 		fs->lfs_idaddr = bp->b_blkno;
754 	} else {
755 		LFS_IENTRY(ifp, fs, ino, ibp);
756 		daddr = ifp->if_daddr;
757 		ifp->if_daddr = bp->b_blkno;
758 #ifdef LFS_DEBUG_NEXTFREE
759 		if(ino > 3 && ifp->if_nextfree) {
760 			vprint("lfs_writeinode",ITOV(ip));
761 			printf("lfs_writeinode: updating free ino %d\n",
762 				ip->i_number);
763 		}
764 #endif
765 		error = VOP_BWRITE(ibp);
766 	}
767 
768 	/*
769 	 * No need to update segment usage if there was no former inode address
770 	 * or if the last inode address is in the current partial segment.
771 	 */
772 	if (daddr != LFS_UNUSED_DADDR &&
773 	    !(daddr >= fs->lfs_lastpseg && daddr <= bp->b_blkno)) {
774 		LFS_SEGENTRY(sup, fs, datosn(fs, daddr), bp);
775 #ifdef DIAGNOSTIC
776 		if (sup->su_nbytes < DINODE_SIZE) {
777 			/* XXX -- Change to a panic. */
778 			printf("lfs_writeinode: negative bytes (segment %d short by %d)\n",
779 			       datosn(fs, daddr), (int)DINODE_SIZE - sup->su_nbytes);
780 			panic("lfs_writeinode: negative bytes");
781 			sup->su_nbytes = DINODE_SIZE;
782 		}
783 #endif
784 		sup->su_nbytes -= DINODE_SIZE;
785 		redo_ifile =
786 			(ino == LFS_IFILE_INUM && !(bp->b_flags & B_GATHERED));
787 		error = VOP_BWRITE(bp);
788 	}
789 	return (redo_ifile);
790 }
791 
792 int
793 lfs_gatherblock(sp, bp, sptr)
794 	struct segment *sp;
795 	struct buf *bp;
796 	int *sptr;
797 {
798 	struct lfs *fs;
799 	int version;
800 
801 	/*
802 	 * If full, finish this segment.  We may be doing I/O, so
803 	 * release and reacquire the splbio().
804 	 */
805 #ifdef DIAGNOSTIC
806 	if (sp->vp == NULL)
807 		panic ("lfs_gatherblock: Null vp in segment");
808 #endif
809 	fs = sp->fs;
810 	if (sp->sum_bytes_left < sizeof(ufs_daddr_t) ||
811 	    sp->seg_bytes_left < bp->b_bcount) {
812 		if (sptr)
813 			splx(*sptr);
814 		lfs_updatemeta(sp);
815 
816 		version = sp->fip->fi_version;
817 		(void) lfs_writeseg(fs, sp);
818 
819 		sp->fip->fi_version = version;
820 		sp->fip->fi_ino = VTOI(sp->vp)->i_number;
821 		/* Add the current file to the segment summary. */
822 		++((SEGSUM *)(sp->segsum))->ss_nfinfo;
823 		sp->sum_bytes_left -=
824 			sizeof(struct finfo) - sizeof(ufs_daddr_t);
825 
826 		if (sptr)
827 			*sptr = splbio();
828 		return(1);
829 	}
830 
831 #ifdef DEBUG
832 	if(bp->b_flags & B_GATHERED) {
833 		printf("lfs_gatherblock: already gathered! Ino %d, lbn %d\n",
834 		       sp->fip->fi_ino, bp->b_lblkno);
835 		return(0);
836 	}
837 #endif
838 	/* Insert into the buffer list, update the FINFO block. */
839 	bp->b_flags |= B_GATHERED;
840 	*sp->cbpp++ = bp;
841 	sp->fip->fi_blocks[sp->fip->fi_nblocks++] = bp->b_lblkno;
842 
843 	sp->sum_bytes_left -= sizeof(ufs_daddr_t);
844 	sp->seg_bytes_left -= bp->b_bcount;
845 	return(0);
846 }
847 
848 int
849 lfs_gather(fs, sp, vp, match)
850 	struct lfs *fs;
851 	struct segment *sp;
852 	struct vnode *vp;
853 	int (*match) __P((struct lfs *, struct buf *));
854 {
855 	struct buf *bp;
856 	int s, count=0;
857 
858 	sp->vp = vp;
859 	s = splbio();
860 
861 #ifndef LFS_NO_BACKBUF_HACK
862 loop:	for (bp = vp->v_dirtyblkhd.lh_first; bp; bp = bp->b_vnbufs.le_next) {
863 #else /* LFS_NO_BACKBUF_HACK */
864 /* This is a hack to see if ordering the blocks in LFS makes a difference. */
865 # define	BUF_OFFSET	(((void *)&bp->b_vnbufs.le_next) - (void *)bp)
866 # define	BACK_BUF(BP)	((struct buf *)(((void *)BP->b_vnbufs.le_prev) - BUF_OFFSET))
867 # define	BEG_OF_LIST	((struct buf *)(((void *)&vp->v_dirtyblkhd.lh_first) - BUF_OFFSET))
868 /* Find last buffer. */
869 loop:	for (bp = vp->v_dirtyblkhd.lh_first; bp && bp->b_vnbufs.le_next != NULL;
870 	    bp = bp->b_vnbufs.le_next);
871 	for (; bp && bp != BEG_OF_LIST; bp = BACK_BUF(bp)) {
872 #endif /* LFS_NO_BACKBUF_HACK */
873 		if ((bp->b_flags & (B_BUSY|B_GATHERED)) || !match(fs, bp))
874 			continue;
875 		if(vp->v_type == VBLK) {
876 			/* For block devices, just write the blocks. */
877 			/* XXX Do we really need to even do this? */
878 #ifdef DEBUG_LFS
879 			if(count==0)
880 				printf("BLK(");
881 			printf(".");
882 #endif
883 			/* Get the block before bwrite, so we don't corrupt the free list */
884 			bp->b_flags |= B_BUSY;
885 			bremfree(bp);
886 			bwrite(bp);
887 		} else {
888 #ifdef DIAGNOSTIC
889 			if (!(bp->b_flags & B_DELWRI))
890 				panic("lfs_gather: bp not B_DELWRI");
891 			if (!(bp->b_flags & B_LOCKED)) {
892 				printf("lfs_gather: lbn %d blk %d not B_LOCKED\n", bp->b_lblkno, bp->b_blkno);
893 				VOP_PRINT(bp->b_vp);
894 				panic("lfs_gather: bp not B_LOCKED");
895 			}
896 #endif
897 			if (lfs_gatherblock(sp, bp, &s)) {
898 				goto loop;
899 			}
900 		}
901 		count++;
902 	}
903 	splx(s);
904 #ifdef DEBUG_LFS
905 	if(vp->v_type == VBLK && count)
906 		printf(")\n");
907 #endif
908 	lfs_updatemeta(sp);
909 	sp->vp = NULL;
910 	return count;
911 }
912 
913 /*
914  * Update the metadata that points to the blocks listed in the FINFO
915  * array.
916  */
917 void
918 lfs_updatemeta(sp)
919 	struct segment *sp;
920 {
921 	SEGUSE *sup;
922 	struct buf *bp;
923 	struct lfs *fs;
924 	struct vnode *vp;
925 	struct indir a[NIADDR + 2], *ap;
926 	struct inode *ip;
927 	ufs_daddr_t daddr, lbn, off;
928 	int error, i, nblocks, num;
929 
930 	vp = sp->vp;
931 	nblocks = &sp->fip->fi_blocks[sp->fip->fi_nblocks] - sp->start_lbp;
932 	if (nblocks < 0)
933 		panic("This is a bad thing\n");
934 	if (vp == NULL || nblocks == 0)
935 		return;
936 
937 	/* Sort the blocks. */
938 	/*
939 	 * XXX KS - We have to sort even if the blocks come from the
940 	 * cleaner, because there might be other pending blocks on the
941 	 * same inode...and if we don't sort, and there are fragments
942 	 * present, blocks may be written in the wrong place.
943 	 */
944 	/* if (!(sp->seg_flags & SEGM_CLEAN)) */
945 	lfs_shellsort(sp->start_bpp, sp->start_lbp, nblocks);
946 
947 	/*
948 	 * Record the length of the last block in case it's a fragment.
949 	 * If there are indirect blocks present, they sort last.  An
950 	 * indirect block will be lfs_bsize and its presence indicates
951 	 * that you cannot have fragments.
952 	 */
953 	sp->fip->fi_lastlength = sp->start_bpp[nblocks - 1]->b_bcount;
954 
955 	/*
956 	 * Assign disk addresses, and update references to the logical
957 	 * block and the segment usage information.
958 	 */
959 	fs = sp->fs;
960 	for (i = nblocks; i--; ++sp->start_bpp) {
961 		lbn = *sp->start_lbp++;
962 
963 		(*sp->start_bpp)->b_blkno = off = fs->lfs_offset;
964 		if((*sp->start_bpp)->b_blkno == (*sp->start_bpp)->b_lblkno) {
965 			printf("lfs_updatemeta: ino %d blk %d has same lbn and daddr\n", VTOI(vp)->i_number, off);
966 		}
967 		fs->lfs_offset +=
968 			fragstodb(fs, numfrags(fs, (*sp->start_bpp)->b_bcount));
969 		error = ufs_bmaparray(vp, lbn, &daddr, a, &num, NULL);
970 		if (error)
971 			panic("lfs_updatemeta: ufs_bmaparray %d", error);
972 		ip = VTOI(vp);
973 		switch (num) {
974 		case 0:
975 			ip->i_ffs_db[lbn] = off;
976 			break;
977 		case 1:
978 			ip->i_ffs_ib[a[0].in_off] = off;
979 			break;
980 		default:
981 			ap = &a[num - 1];
982 			if (bread(vp, ap->in_lbn, fs->lfs_bsize, NOCRED, &bp))
983 				panic("lfs_updatemeta: bread bno %d",
984 				      ap->in_lbn);
985 			/*
986 			 * Bread may create a new (indirect) block which needs
987 			 * to get counted for the inode.
988 			 */
989 			if (/* bp->b_blkno == -1 && */
990 			    !(bp->b_flags & (B_DELWRI|B_DONE))) {
991 				ip->i_ffs_blocks += fsbtodb(fs, 1);
992 				fs->lfs_bfree -= fragstodb(fs, fs->lfs_frag);
993 			}
994 			((ufs_daddr_t *)bp->b_data)[ap->in_off] = off;
995 			VOP_BWRITE(bp);
996 		}
997 		/* Update segment usage information. */
998 		if (daddr != UNASSIGNED && !(daddr >= fs->lfs_lastpseg && daddr <= off)) {
999 			LFS_SEGENTRY(sup, fs, datosn(fs, daddr), bp);
1000 #ifdef DIAGNOSTIC
1001 			if (sup->su_nbytes < (*sp->start_bpp)->b_bcount) {
1002 				/* XXX -- Change to a panic. */
1003 				printf("lfs_updatemeta: negative bytes (segment %d short by %ld)\n",
1004 				       datosn(fs, daddr), (*sp->start_bpp)->b_bcount - sup->su_nbytes);
1005 				printf("lfs_updatemeta: ino %d, lbn %d, addr = %x\n",
1006 				       VTOI(sp->vp)->i_number, (*sp->start_bpp)->b_lblkno, daddr);
1007 				panic("lfs_updatemeta: negative bytes");
1008 				sup->su_nbytes = (*sp->start_bpp)->b_bcount;
1009 			}
1010 #endif
1011 			sup->su_nbytes -= (*sp->start_bpp)->b_bcount;
1012 			error = VOP_BWRITE(bp);
1013 		}
1014 	}
1015 }
1016 
1017 /*
1018  * Start a new segment.
1019  */
1020 int
1021 lfs_initseg(fs)
1022 	struct lfs *fs;
1023 {
1024 	struct segment *sp;
1025 	SEGUSE *sup;
1026 	SEGSUM *ssp;
1027 	struct buf *bp;
1028 	int repeat;
1029 
1030 	sp = fs->lfs_sp;
1031 
1032 	repeat = 0;
1033 	/* Advance to the next segment. */
1034 	if (!LFS_PARTIAL_FITS(fs)) {
1035 		/* Wake up any cleaning procs waiting on this file system. */
1036 		wakeup(&lfs_allclean_wakeup);
1037 		wakeup(&fs->lfs_nextseg);
1038 		lfs_newseg(fs);
1039 		repeat = 1;
1040 		fs->lfs_offset = fs->lfs_curseg;
1041 		sp->seg_number = datosn(fs, fs->lfs_curseg);
1042 		sp->seg_bytes_left = fs->lfs_dbpseg * DEV_BSIZE;
1043 		/*
1044 		 * If the segment contains a superblock, update the offset
1045 		 * and summary address to skip over it.
1046 		 */
1047 		LFS_SEGENTRY(sup, fs, sp->seg_number, bp);
1048 		if (sup->su_flags & SEGUSE_SUPERBLOCK) {
1049 			fs->lfs_offset += LFS_SBPAD / DEV_BSIZE;
1050 			sp->seg_bytes_left -= LFS_SBPAD;
1051 		}
1052 		brelse(bp);
1053 	} else {
1054 		sp->seg_number = datosn(fs, fs->lfs_curseg);
1055 		sp->seg_bytes_left = (fs->lfs_dbpseg -
1056 				      (fs->lfs_offset - fs->lfs_curseg)) * DEV_BSIZE;
1057 	}
1058 	fs->lfs_lastpseg = fs->lfs_offset;
1059 
1060 	sp->fs = fs;
1061 	sp->ibp = NULL;
1062 	sp->idp = NULL;
1063 	sp->ninodes = 0;
1064 
1065 	/* Get a new buffer for SEGSUM and enter it into the buffer list. */
1066 	sp->cbpp = sp->bpp;
1067 	*sp->cbpp = lfs_newbuf(VTOI(fs->lfs_ivnode)->i_devvp,
1068 			       fs->lfs_offset, LFS_SUMMARY_SIZE);
1069 	sp->segsum = (*sp->cbpp)->b_data;
1070 	bzero(sp->segsum, LFS_SUMMARY_SIZE);
1071 	sp->start_bpp = ++sp->cbpp;
1072 	fs->lfs_offset += LFS_SUMMARY_SIZE / DEV_BSIZE;
1073 
1074 	/* Set point to SEGSUM, initialize it. */
1075 	ssp = sp->segsum;
1076 	ssp->ss_next = fs->lfs_nextseg;
1077 	ssp->ss_nfinfo = ssp->ss_ninos = 0;
1078 	ssp->ss_magic = SS_MAGIC;
1079 
1080 	/* Set pointer to first FINFO, initialize it. */
1081 	sp->fip = (struct finfo *)((caddr_t)sp->segsum + sizeof(SEGSUM));
1082 	sp->fip->fi_nblocks = 0;
1083 	sp->start_lbp = &sp->fip->fi_blocks[0];
1084 	sp->fip->fi_lastlength = 0;
1085 
1086 	sp->seg_bytes_left -= LFS_SUMMARY_SIZE;
1087 	sp->sum_bytes_left = LFS_SUMMARY_SIZE - sizeof(SEGSUM);
1088 
1089 	return(repeat);
1090 }
1091 
1092 /*
1093  * Return the next segment to write.
1094  */
1095 void
1096 lfs_newseg(fs)
1097 	struct lfs *fs;
1098 {
1099 	CLEANERINFO *cip;
1100 	SEGUSE *sup;
1101 	struct buf *bp;
1102 	int curseg, isdirty, sn;
1103 
1104 	LFS_SEGENTRY(sup, fs, datosn(fs, fs->lfs_nextseg), bp);
1105 	sup->su_flags |= SEGUSE_DIRTY | SEGUSE_ACTIVE;
1106 	sup->su_nbytes = 0;
1107 	sup->su_nsums = 0;
1108 	sup->su_ninos = 0;
1109 	(void) VOP_BWRITE(bp);
1110 
1111 	LFS_CLEANERINFO(cip, fs, bp);
1112 	--cip->clean;
1113 	++cip->dirty;
1114 	fs->lfs_nclean = cip->clean;
1115 	(void) VOP_BWRITE(bp);
1116 
1117 	fs->lfs_lastseg = fs->lfs_curseg;
1118 	fs->lfs_curseg = fs->lfs_nextseg;
1119 	for (sn = curseg = datosn(fs, fs->lfs_curseg);;) {
1120 		sn = (sn + 1) % fs->lfs_nseg;
1121 		if (sn == curseg)
1122 			panic("lfs_nextseg: no clean segments");
1123 		LFS_SEGENTRY(sup, fs, sn, bp);
1124 		isdirty = sup->su_flags & SEGUSE_DIRTY;
1125 		brelse(bp);
1126 		if (!isdirty)
1127 			break;
1128 	}
1129 
1130 	++fs->lfs_nactive;
1131 	fs->lfs_nextseg = sntoda(fs, sn);
1132 	if(lfs_dostats) {
1133 		++lfs_stats.segsused;
1134 	}
1135 }
1136 
1137 int
1138 lfs_writeseg(fs, sp)
1139 	struct lfs *fs;
1140 	struct segment *sp;
1141 {
1142 	extern int locked_queue_count;
1143 	extern long locked_queue_bytes;
1144 	struct buf **bpp, *bp, *cbp;
1145 	SEGUSE *sup;
1146 	SEGSUM *ssp;
1147 	dev_t i_dev;
1148 	u_long *datap, *dp;
1149 	int do_again, i, nblocks, s;
1150 #ifdef LFS_TRACK_IOS
1151 	int j;
1152 #endif
1153 	int (*strategy)__P((void *));
1154 	struct vop_strategy_args vop_strategy_a;
1155 	u_short ninos;
1156 	struct vnode *devvp;
1157 	char *p;
1158 	struct vnode *vn;
1159 	struct inode *ip;
1160 #if defined(DEBUG) && defined(LFS_PROPELLER)
1161 	static int propeller;
1162 	char propstring[4] = "-\\|/";
1163 
1164 	printf("%c\b",propstring[propeller++]);
1165 	if(propeller==4)
1166 		propeller = 0;
1167 #endif
1168 
1169 	/*
1170 	 * If there are no buffers other than the segment summary to write
1171 	 * and it is not a checkpoint, don't do anything.  On a checkpoint,
1172 	 * even if there aren't any buffers, you need to write the superblock.
1173 	 */
1174 	if ((nblocks = sp->cbpp - sp->bpp) == 1)
1175 		return (0);
1176 
1177 #ifdef DEBUG_LFS
1178 	lfs_check_bpp(fs,sp,__FILE__,__LINE__);
1179 #endif
1180 	i_dev = VTOI(fs->lfs_ivnode)->i_dev;
1181 	devvp = VTOI(fs->lfs_ivnode)->i_devvp;
1182 
1183 	/* Update the segment usage information. */
1184 	LFS_SEGENTRY(sup, fs, sp->seg_number, bp);
1185 
1186 	/* Loop through all blocks, except the segment summary. */
1187 	for (bpp = sp->bpp; ++bpp < sp->cbpp; ) {
1188 		if((*bpp)->b_vp != devvp)
1189 			sup->su_nbytes += (*bpp)->b_bcount;
1190 	}
1191 
1192 	ssp = (SEGSUM *)sp->segsum;
1193 
1194 	ninos = (ssp->ss_ninos + INOPB(fs) - 1) / INOPB(fs);
1195 	sup->su_nbytes += ssp->ss_ninos * DINODE_SIZE;
1196 	/* sup->su_nbytes += LFS_SUMMARY_SIZE; */
1197 	sup->su_lastmod = time.tv_sec;
1198 	sup->su_ninos += ninos;
1199 	++sup->su_nsums;
1200 
1201 	do_again = !(bp->b_flags & B_GATHERED);
1202 	(void)VOP_BWRITE(bp);
1203 	/*
1204 	 * Compute checksum across data and then across summary; the first
1205 	 * block (the summary block) is skipped.  Set the create time here
1206 	 * so that it's guaranteed to be later than the inode mod times.
1207 	 *
1208 	 * XXX
1209 	 * Fix this to do it inline, instead of malloc/copy.
1210 	 */
1211 	datap = dp = malloc(nblocks * sizeof(u_long), M_SEGMENT, M_WAITOK);
1212 	for (bpp = sp->bpp, i = nblocks - 1; i--;) {
1213 		if (((*++bpp)->b_flags & (B_CALL|B_INVAL)) == (B_CALL|B_INVAL)) {
1214 			if (copyin((*bpp)->b_saveaddr, dp++, sizeof(u_long)))
1215 				panic("lfs_writeseg: copyin failed [1]: ino %d blk %d", VTOI((*bpp)->b_vp)->i_number, (*bpp)->b_lblkno);
1216 		} else {
1217 			if( !((*bpp)->b_flags & B_CALL) ) {
1218 				/*
1219 				 * Before we record data for a checksm,
1220 				 * make sure the data won't change in between
1221 				 * the checksum calculation and the write,
1222 				 * by marking the buffer B_BUSY.  It will
1223 				 * be freed later by brelse().
1224 				 */
1225 			again:
1226 				s = splbio();
1227 				if((*bpp)->b_flags & B_BUSY) {
1228 #ifdef DEBUG
1229 					printf("lfs_writeseg: avoiding potential data summary corruption for ino %d, lbn %d\n",
1230 					       VTOI((*bpp)->b_vp)->i_number,
1231 					       bp->b_lblkno);
1232 #endif
1233 					(*bpp)->b_flags |= B_WANTED;
1234 					tsleep((*bpp), (PRIBIO + 1),
1235 					       "lfs_writeseg", 0);
1236 					splx(s);
1237 					goto again;
1238 				}
1239 				(*bpp)->b_flags |= B_BUSY;
1240 				splx(s);
1241 			}
1242 			*dp++ = ((u_long *)(*bpp)->b_data)[0];
1243 		}
1244 	}
1245 	ssp->ss_create = time.tv_sec;
1246 	ssp->ss_datasum = cksum(datap, (nblocks - 1) * sizeof(u_long));
1247 	ssp->ss_sumsum =
1248 	    cksum(&ssp->ss_datasum, LFS_SUMMARY_SIZE - sizeof(ssp->ss_sumsum));
1249 	free(datap, M_SEGMENT);
1250 #ifdef DIAGNOSTIC
1251 	if (fs->lfs_bfree < fsbtodb(fs, ninos) + LFS_SUMMARY_SIZE / DEV_BSIZE)
1252 		panic("lfs_writeseg: No diskspace for summary");
1253 #endif
1254 	fs->lfs_bfree -= (fsbtodb(fs, ninos) + LFS_SUMMARY_SIZE / DEV_BSIZE);
1255 
1256 	strategy = devvp->v_op[VOFFSET(vop_strategy)];
1257 
1258 	/*
1259 	 * When we simply write the blocks we lose a rotation for every block
1260 	 * written.  To avoid this problem, we allocate memory in chunks, copy
1261 	 * the buffers into the chunk and write the chunk.  CHUNKSIZE is the
1262 	 * largest size I/O devices can handle.
1263 	 * When the data is copied to the chunk, turn off the the B_LOCKED bit
1264 	 * and brelse the buffer (which will move them to the LRU list).  Add
1265 	 * the B_CALL flag to the buffer header so we can count I/O's for the
1266 	 * checkpoints and so we can release the allocated memory.
1267 	 *
1268 	 * XXX
1269 	 * This should be removed if the new virtual memory system allows us to
1270 	 * easily make the buffers contiguous in kernel memory and if that's
1271 	 * fast enough.
1272 	 */
1273 
1274 #define CHUNKSIZE MAXPHYS
1275 
1276 	if(devvp==NULL)
1277 		panic("devvp is NULL");
1278 	for (bpp = sp->bpp,i = nblocks; i;) {
1279 		cbp = lfs_newbuf(devvp, (*bpp)->b_blkno, CHUNKSIZE);
1280 		cbp->b_dev = i_dev;
1281 		cbp->b_flags |= B_ASYNC | B_BUSY;
1282 		cbp->b_bcount = 0;
1283 
1284 #ifdef DIAGNOSTIC
1285 		if(datosn(fs,(*bpp)->b_blkno + ((*bpp)->b_bcount - 1)/DEV_BSIZE) != datosn(fs,cbp->b_blkno)) {
1286 			panic("lfs_writeseg: Segment overwrite");
1287 		}
1288 #endif
1289 
1290 		s = splbio();
1291 		if(fs->lfs_iocount >= LFS_THROTTLE) {
1292 			tsleep(&fs->lfs_iocount, PRIBIO+1, "lfs throttle", 0);
1293 		}
1294 		++fs->lfs_iocount;
1295 #ifdef LFS_TRACK_IOS
1296 		for(j=0;j<LFS_THROTTLE;j++) {
1297 			if(fs->lfs_pending[j]==LFS_UNUSED_DADDR) {
1298 				fs->lfs_pending[j] = cbp->b_blkno;
1299 				break;
1300 			}
1301 		}
1302 #endif /* LFS_TRACK_IOS */
1303 		for (p = cbp->b_data; i && cbp->b_bcount < CHUNKSIZE; i--) {
1304 			bp = *bpp;
1305 
1306 			if (bp->b_bcount > (CHUNKSIZE - cbp->b_bcount))
1307 				break;
1308 
1309 			/*
1310 			 * Fake buffers from the cleaner are marked as B_INVAL.
1311 			 * We need to copy the data from user space rather than
1312 			 * from the buffer indicated.
1313 			 * XXX == what do I do on an error?
1314 			 */
1315 			if ((bp->b_flags & (B_CALL|B_INVAL)) == (B_CALL|B_INVAL)) {
1316 				if (copyin(bp->b_saveaddr, p, bp->b_bcount))
1317 					panic("lfs_writeseg: copyin failed [2]");
1318 			} else
1319 				bcopy(bp->b_data, p, bp->b_bcount);
1320 			p += bp->b_bcount;
1321 			cbp->b_bcount += bp->b_bcount;
1322 			if (bp->b_flags & B_LOCKED) {
1323 				--locked_queue_count;
1324 				locked_queue_bytes -= bp->b_bufsize;
1325 			}
1326 			bp->b_flags &= ~(B_ERROR | B_READ | B_DELWRI |
1327 					 B_LOCKED | B_GATHERED);
1328 			vn = bp->b_vp;
1329 			if (bp->b_flags & B_CALL) {
1330 				/* if B_CALL, it was created with newbuf */
1331 				lfs_freebuf(bp);
1332 			} else {
1333 				bremfree(bp);
1334 				bp->b_flags |= B_DONE;
1335 				if(vn)
1336 					reassignbuf(bp, vn);
1337 				brelse(bp);
1338 			}
1339 			if(bp->b_flags & B_NEEDCOMMIT) { /* XXX */
1340 				bp->b_flags &= ~B_NEEDCOMMIT;
1341 				wakeup(bp);
1342 			}
1343 
1344 			bpp++;
1345 
1346 			/*
1347 			 * If this is the last block for this vnode, but
1348 			 * there are other blocks on its dirty list,
1349 			 * set IN_MODIFIED/IN_CLEANING depending on what
1350 			 * sort of block.  Only do this for our mount point,
1351 			 * not for, e.g., inode blocks that are attached to
1352 			 * the devvp.
1353 			 */
1354 			if(i>1 && vn && *bpp && (*bpp)->b_vp != vn
1355 			   && (*bpp)->b_vp && (bp=vn->v_dirtyblkhd.lh_first)!=NULL &&
1356 			   vn->v_mount == fs->lfs_ivnode->v_mount)
1357 			{
1358 				ip = VTOI(vn);
1359 #ifdef DEBUG_LFS
1360 				printf("lfs_writeseg: marking ino %d\n",ip->i_number);
1361 #endif
1362 		       		if(!(ip->i_flag & (IN_CLEANING|IN_MODIFIED))) {
1363 					fs->lfs_uinodes++;
1364 					if(bp->b_flags & B_CALL)
1365 						ip->i_flag |= IN_CLEANING;
1366 					else
1367 						ip->i_flag |= IN_MODIFIED;
1368 				}
1369 			}
1370 			/* if(vn->v_dirtyblkhd.lh_first == NULL) */
1371 				wakeup(vn);
1372 		}
1373 		++cbp->b_vp->v_numoutput;
1374 		splx(s);
1375 		/*
1376 		 * XXXX This is a gross and disgusting hack.  Since these
1377 		 * buffers are physically addressed, they hang off the
1378 		 * device vnode (devvp).  As a result, they have no way
1379 		 * of getting to the LFS superblock or lfs structure to
1380 		 * keep track of the number of I/O's pending.  So, I am
1381 		 * going to stuff the fs into the saveaddr field of
1382 		 * the buffer (yuk).
1383 		 */
1384 		cbp->b_saveaddr = (caddr_t)fs;
1385 		vop_strategy_a.a_desc = VDESC(vop_strategy);
1386 		vop_strategy_a.a_bp = cbp;
1387 		(strategy)(&vop_strategy_a);
1388 	}
1389 	/*
1390 	 * XXX
1391 	 * Vinvalbuf can move locked buffers off the locked queue
1392 	 * and we have no way of knowing about this.  So, after
1393 	 * doing a big write, we recalculate how many buffers are
1394 	 * really still left on the locked queue.
1395 	 */
1396 	lfs_countlocked(&locked_queue_count,&locked_queue_bytes);
1397 	wakeup(&locked_queue_count);
1398 	if(lfs_dostats) {
1399 		++lfs_stats.psegwrites;
1400 		lfs_stats.blocktot += nblocks - 1;
1401 		if (fs->lfs_sp->seg_flags & SEGM_SYNC)
1402 			++lfs_stats.psyncwrites;
1403 		if (fs->lfs_sp->seg_flags & SEGM_CLEAN) {
1404 			++lfs_stats.pcleanwrites;
1405 			lfs_stats.cleanblocks += nblocks - 1;
1406 		}
1407 	}
1408 	return (lfs_initseg(fs) || do_again);
1409 }
1410 
1411 void
1412 lfs_writesuper(fs, daddr)
1413 	struct lfs *fs;
1414 	daddr_t daddr;
1415 {
1416 	struct buf *bp;
1417 	dev_t i_dev;
1418 	int (*strategy) __P((void *));
1419 	int s;
1420 	struct vop_strategy_args vop_strategy_a;
1421 
1422 #ifdef LFS_CANNOT_ROLLFW
1423 	/*
1424 	 * If we can write one superblock while another is in
1425 	 * progress, we risk not having a complete checkpoint if we crash.
1426 	 * So, block here if a superblock write is in progress.
1427 	 */
1428 	s = splbio();
1429 	while(fs->lfs_sbactive) {
1430 		tsleep(&fs->lfs_sbactive, PRIBIO+1, "lfs sb", 0);
1431 	}
1432 	fs->lfs_sbactive = daddr;
1433 	splx(s);
1434 #endif
1435 	i_dev = VTOI(fs->lfs_ivnode)->i_dev;
1436 	strategy = VTOI(fs->lfs_ivnode)->i_devvp->v_op[VOFFSET(vop_strategy)];
1437 
1438 	/* Set timestamp of this version of the superblock */
1439 	fs->lfs_tstamp = time.tv_sec;
1440 
1441 	/* Checksum the superblock and copy it into a buffer. */
1442 	fs->lfs_cksum = lfs_sb_cksum(&(fs->lfs_dlfs));
1443 	bp = lfs_newbuf(VTOI(fs->lfs_ivnode)->i_devvp, daddr, LFS_SBPAD);
1444 	*(struct dlfs *)bp->b_data = fs->lfs_dlfs;
1445 
1446 	bp->b_dev = i_dev;
1447 	bp->b_flags |= B_BUSY | B_CALL | B_ASYNC;
1448 	bp->b_flags &= ~(B_DONE | B_ERROR | B_READ | B_DELWRI);
1449 	bp->b_iodone = lfs_supercallback;
1450 	/* XXX KS - same nasty hack as above */
1451 	bp->b_saveaddr = (caddr_t)fs;
1452 
1453 	vop_strategy_a.a_desc = VDESC(vop_strategy);
1454 	vop_strategy_a.a_bp = bp;
1455 	s = splbio();
1456 	++bp->b_vp->v_numoutput;
1457 	splx(s);
1458 	(strategy)(&vop_strategy_a);
1459 }
1460 
1461 /*
1462  * Logical block number match routines used when traversing the dirty block
1463  * chain.
1464  */
1465 int
1466 lfs_match_fake(fs, bp)
1467 	struct lfs *fs;
1468 	struct buf *bp;
1469 {
1470 	return (bp->b_flags & B_CALL);
1471 }
1472 
1473 int
1474 lfs_match_data(fs, bp)
1475 	struct lfs *fs;
1476 	struct buf *bp;
1477 {
1478 	return (bp->b_lblkno >= 0);
1479 }
1480 
1481 int
1482 lfs_match_indir(fs, bp)
1483 	struct lfs *fs;
1484 	struct buf *bp;
1485 {
1486 	int lbn;
1487 
1488 	lbn = bp->b_lblkno;
1489 	return (lbn < 0 && (-lbn - NDADDR) % NINDIR(fs) == 0);
1490 }
1491 
1492 int
1493 lfs_match_dindir(fs, bp)
1494 	struct lfs *fs;
1495 	struct buf *bp;
1496 {
1497 	int lbn;
1498 
1499 	lbn = bp->b_lblkno;
1500 	return (lbn < 0 && (-lbn - NDADDR) % NINDIR(fs) == 1);
1501 }
1502 
1503 int
1504 lfs_match_tindir(fs, bp)
1505 	struct lfs *fs;
1506 	struct buf *bp;
1507 {
1508 	int lbn;
1509 
1510 	lbn = bp->b_lblkno;
1511 	return (lbn < 0 && (-lbn - NDADDR) % NINDIR(fs) == 2);
1512 }
1513 
1514 /*
1515  * XXX - The only buffers that are going to hit these functions are the
1516  * segment write blocks, or the segment summaries, or the superblocks.
1517  *
1518  * All of the above are created by lfs_newbuf, and so do not need to be
1519  * released via brelse.
1520  */
1521 void
1522 lfs_callback(bp)
1523 	struct buf *bp;
1524 {
1525 	struct lfs *fs;
1526 #ifdef LFS_TRACK_IOS
1527 	int j;
1528 #endif
1529 
1530 	fs = (struct lfs *)bp->b_saveaddr;
1531 #ifdef DIAGNOSTIC
1532 	if (fs->lfs_iocount == 0)
1533 		panic("lfs_callback: zero iocount\n");
1534 #endif
1535 	if (--fs->lfs_iocount < LFS_THROTTLE)
1536 		wakeup(&fs->lfs_iocount);
1537 #ifdef LFS_TRACK_IOS
1538 	for(j=0;j<LFS_THROTTLE;j++) {
1539 		if(fs->lfs_pending[j]==bp->b_blkno) {
1540 			fs->lfs_pending[j] = LFS_UNUSED_DADDR;
1541 			wakeup(&(fs->lfs_pending[j]));
1542 			break;
1543 		}
1544 	}
1545 #endif /* LFS_TRACK_IOS */
1546 
1547 	lfs_freebuf(bp);
1548 }
1549 
1550 void
1551 lfs_supercallback(bp)
1552 	struct buf *bp;
1553 {
1554 #ifdef LFS_CANNOT_ROLLFW
1555 	struct lfs *fs;
1556 
1557 	fs = (struct lfs *)bp->b_saveaddr;
1558 	fs->lfs_sbactive=NULL;
1559 	wakeup(&fs->lfs_sbactive);
1560 #endif
1561 	lfs_freebuf(bp);
1562 }
1563 
1564 /*
1565  * Shellsort (diminishing increment sort) from Data Structures and
1566  * Algorithms, Aho, Hopcraft and Ullman, 1983 Edition, page 290;
1567  * see also Knuth Vol. 3, page 84.  The increments are selected from
1568  * formula (8), page 95.  Roughly O(N^3/2).
1569  */
1570 /*
1571  * This is our own private copy of shellsort because we want to sort
1572  * two parallel arrays (the array of buffer pointers and the array of
1573  * logical block numbers) simultaneously.  Note that we cast the array
1574  * of logical block numbers to a unsigned in this routine so that the
1575  * negative block numbers (meta data blocks) sort AFTER the data blocks.
1576  */
1577 
1578 void
1579 lfs_shellsort(bp_array, lb_array, nmemb)
1580 	struct buf **bp_array;
1581 	ufs_daddr_t *lb_array;
1582 	register int nmemb;
1583 {
1584 	static int __rsshell_increments[] = { 4, 1, 0 };
1585 	register int incr, *incrp, t1, t2;
1586 	struct buf *bp_temp;
1587 	u_long lb_temp;
1588 
1589 	for (incrp = __rsshell_increments; (incr = *incrp++) != 0;)
1590 		for (t1 = incr; t1 < nmemb; ++t1)
1591 			for (t2 = t1 - incr; t2 >= 0;)
1592 				if (lb_array[t2] > lb_array[t2 + incr]) {
1593 					lb_temp = lb_array[t2];
1594 					lb_array[t2] = lb_array[t2 + incr];
1595 					lb_array[t2 + incr] = lb_temp;
1596 					bp_temp = bp_array[t2];
1597 					bp_array[t2] = bp_array[t2 + incr];
1598 					bp_array[t2 + incr] = bp_temp;
1599 					t2 -= incr;
1600 				} else
1601 					break;
1602 }
1603 
1604 /*
1605  * Check VXLOCK.  Return 1 if the vnode is locked.  Otherwise, vget it.
1606  */
1607 int
1608 lfs_vref(vp)
1609 	register struct vnode *vp;
1610 {
1611 	/*
1612 	 * If we return 1 here during a flush, we risk vinvalbuf() not
1613 	 * being able to flush all of the pages from this vnode, which
1614 	 * will cause it to panic.  So, return 0 if a flush is in progress.
1615 	 */
1616 	if (vp->v_flag & VXLOCK) {
1617 		if(IS_FLUSHING(VTOI(vp)->i_lfs,vp)) {
1618 			return 0;
1619 		}
1620 		return(1);
1621 	}
1622 	return (vget(vp, 0));
1623 }
1624 
1625 /*
1626  * This is vrele except that we do not want to VOP_INACTIVE this vnode. We
1627  * inline vrele here to avoid the vn_lock and VOP_INACTIVE call at the end.
1628  */
1629 void
1630 lfs_vunref(vp)
1631 	register struct vnode *vp;
1632 {
1633 	/*
1634 	 * Analogous to lfs_vref, if the node is flushing, fake it.
1635 	 */
1636 	if((vp->v_flag & VXLOCK) && IS_FLUSHING(VTOI(vp)->i_lfs,vp)) {
1637 		return;
1638 	}
1639 
1640 	simple_lock(&vp->v_interlock);
1641 #ifdef DIAGNOSTIC
1642 	if(vp->v_usecount<=0) {
1643 		printf("lfs_vunref: flags are 0x%lx\n", vp->v_flag);
1644 		printf("lfs_vunref: usecount = %ld\n", vp->v_usecount);
1645 		panic("lfs_vunref: v_usecount<0");
1646 	}
1647 #endif
1648 	vp->v_usecount--;
1649 	if (vp->v_usecount > 0) {
1650 		simple_unlock(&vp->v_interlock);
1651 		return;
1652 	}
1653 #ifdef DIAGNOSTIC
1654 	if(VOP_ISLOCKED(vp))
1655 		panic("lfs_vunref: vnode locked");
1656 #endif
1657 	/*
1658 	 * insert at tail of LRU list
1659 	 */
1660 	simple_lock(&vnode_free_list_slock);
1661 	TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
1662 	simple_unlock(&vnode_free_list_slock);
1663 	simple_unlock(&vp->v_interlock);
1664 }
1665 
1666 /*
1667  * We use this when we have vnodes that were loaded in solely for cleaning.
1668  * There is no reason to believe that these vnodes will be referenced again
1669  * soon, since the cleaning process is unrelated to normal filesystem
1670  * activity.  Putting cleaned vnodes at the tail of the list has the effect
1671  * of flushing the vnode LRU.  So, put vnodes that were loaded only for
1672  * cleaning at the head of the list, instead.
1673  */
1674 void
1675 lfs_vunref_head(vp)
1676 	register struct vnode *vp;
1677 {
1678 	simple_lock(&vp->v_interlock);
1679 #ifdef DIAGNOSTIC
1680 	if(vp->v_usecount==0) {
1681 		panic("lfs_vunref: v_usecount<0");
1682 	}
1683 #endif
1684 	vp->v_usecount--;
1685 	if (vp->v_usecount > 0) {
1686 		simple_unlock(&vp->v_interlock);
1687 		return;
1688 	}
1689 #ifdef DIAGNOSTIC
1690 	if(VOP_ISLOCKED(vp))
1691 		panic("lfs_vunref_head: vnode locked");
1692 #endif
1693 	/*
1694 	 * insert at head of LRU list
1695 	 */
1696 	simple_lock(&vnode_free_list_slock);
1697 	TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
1698 	simple_unlock(&vnode_free_list_slock);
1699 	simple_unlock(&vp->v_interlock);
1700 }
1701 
1702