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      1 /* $NetBSD: segwrite.c,v 1.48 2020/05/14 08:34:17 msaitoh Exp $ */
      2 /*-
      3  * Copyright (c) 2003 The NetBSD Foundation, Inc.
      4  * All rights reserved.
      5  *
      6  * This code is derived from software contributed to The NetBSD Foundation
      7  * by Konrad E. Schroder <perseant (at) hhhh.org>.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     20  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     21  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     22  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     28  * POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 /*
     31  * Copyright (c) 1991, 1993
     32  *	The Regents of the University of California.  All rights reserved.
     33  *
     34  * Redistribution and use in source and binary forms, with or without
     35  * modification, are permitted provided that the following conditions
     36  * are met:
     37  * 1. Redistributions of source code must retain the above copyright
     38  *    notice, this list of conditions and the following disclaimer.
     39  * 2. Redistributions in binary form must reproduce the above copyright
     40  *    notice, this list of conditions and the following disclaimer in the
     41  *    documentation and/or other materials provided with the distribution.
     42  * 3. Neither the name of the University nor the names of its contributors
     43  *    may be used to endorse or promote products derived from this software
     44  *    without specific prior written permission.
     45  *
     46  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     49  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     56  * SUCH DAMAGE.
     57  *
     58  *	@(#)lfs_segment.c	8.10 (Berkeley) 6/10/95
     59  */
     60 
     61 /*
     62  * Partial segment writer, taken from the kernel and adapted for userland.
     63  */
     64 #include <sys/types.h>
     65 #include <sys/param.h>
     66 #include <sys/time.h>
     67 #include <sys/buf.h>
     68 #include <sys/mount.h>
     69 
     70 /* Override certain things to make <ufs/lfs/lfs.h> work */
     71 #define VU_DIROP 0x01000000 /* XXX XXX from sys/vnode.h */
     72 #define vnode uvnode
     73 #define buf ubuf
     74 #define panic call_panic
     75 
     76 #include <ufs/lfs/lfs.h>
     77 #include <ufs/lfs/lfs_accessors.h>
     78 #include <ufs/lfs/lfs_inode.h>
     79 
     80 #include <assert.h>
     81 #include <stdio.h>
     82 #include <stdlib.h>
     83 #include <string.h>
     84 #include <err.h>
     85 #include <errno.h>
     86 #include <util.h>
     87 
     88 #include "bufcache.h"
     89 #include "extern.h"
     90 #include "lfs_user.h"
     91 #include "segwrite.h"
     92 
     93 /* Compatibility definitions */
     94 off_t written_bytes = 0;
     95 off_t written_data = 0;
     96 off_t written_indir = 0;
     97 off_t written_dev = 0;
     98 int written_inodes = 0;
     99 
    100 /* Global variables */
    101 time_t write_time;
    102 
    103 static void lfs_shellsort(struct lfs *,
    104 			  struct ubuf **, union lfs_blocks *, int, int);
    105 
    106 /*
    107  * Logical block number match routines used when traversing the dirty block
    108  * chain.
    109  */
    110 int
    111 lfs_match_data(struct lfs * fs, struct ubuf * bp)
    112 {
    113 	return (bp->b_lblkno >= 0);
    114 }
    115 
    116 int
    117 lfs_match_indir(struct lfs * fs, struct ubuf * bp)
    118 {
    119 	daddr_t lbn;
    120 
    121 	lbn = bp->b_lblkno;
    122 	return (lbn < 0 && (-lbn - ULFS_NDADDR) % LFS_NINDIR(fs) == 0);
    123 }
    124 
    125 int
    126 lfs_match_dindir(struct lfs * fs, struct ubuf * bp)
    127 {
    128 	daddr_t lbn;
    129 
    130 	lbn = bp->b_lblkno;
    131 	return (lbn < 0 && (-lbn - ULFS_NDADDR) % LFS_NINDIR(fs) == 1);
    132 }
    133 
    134 int
    135 lfs_match_tindir(struct lfs * fs, struct ubuf * bp)
    136 {
    137 	daddr_t lbn;
    138 
    139 	lbn = bp->b_lblkno;
    140 	return (lbn < 0 && (-lbn - ULFS_NDADDR) % LFS_NINDIR(fs) == 2);
    141 }
    142 
    143 /*
    144  * Do a checkpoint.
    145  */
    146 int
    147 lfs_segwrite(struct lfs * fs, int flags)
    148 {
    149 	struct inode *ip;
    150 	struct segment *sp;
    151 	struct uvnode *vp;
    152 	SEGSUM *ssp;
    153 	int redo;
    154 
    155 	lfs_seglock(fs, flags | SEGM_CKP);
    156 	sp = fs->lfs_sp;
    157 
    158 	lfs_writevnodes(fs, sp, VN_REG);
    159 	lfs_writevnodes(fs, sp, VN_DIROP);
    160 	ssp = (SEGSUM *)sp->segsum;
    161 	lfs_ss_setflags(fs, ssp, lfs_ss_getflags(fs, ssp) & ~(SS_CONT));
    162 
    163 	do {
    164 		vp = fs->lfs_ivnode;
    165 		fs->lfs_flags &= ~LFS_IFDIRTY;
    166 		ip = VTOI(vp);
    167 		if (LIST_FIRST(&vp->v_dirtyblkhd) != NULL || lfs_sb_getidaddr(fs) <= 0)
    168 			lfs_writefile(fs, sp, vp);
    169 
    170 		redo = lfs_writeinode(fs, sp, ip);
    171 		redo += lfs_writeseg(fs, sp);
    172 		redo += (fs->lfs_flags & LFS_IFDIRTY);
    173 	} while (redo);
    174 
    175 	lfs_segunlock(fs);
    176 #if 0
    177 	printf("wrote %" PRId64 " bytes (%" PRId32 " fsb)\n",
    178 		written_bytes, (ulfs_daddr_t)lfs_btofsb(fs, written_bytes));
    179 	printf("wrote %" PRId64 " bytes data (%" PRId32 " fsb)\n",
    180 		written_data, (ulfs_daddr_t)lfs_btofsb(fs, written_data));
    181 	printf("wrote %" PRId64 " bytes indir (%" PRId32 " fsb)\n",
    182 		written_indir, (ulfs_daddr_t)lfs_btofsb(fs, written_indir));
    183 	printf("wrote %" PRId64 " bytes dev (%" PRId32 " fsb)\n",
    184 		written_dev, (ulfs_daddr_t)lfs_btofsb(fs, written_dev));
    185 	printf("wrote %d inodes (%" PRId32 " fsb)\n",
    186 		written_inodes, lfs_btofsb(fs, written_inodes * fs->lfs_ibsize));
    187 #endif
    188 	return 0;
    189 }
    190 
    191 /*
    192  * Write the dirty blocks associated with a vnode.
    193  */
    194 void
    195 lfs_writefile(struct lfs * fs, struct segment * sp, struct uvnode * vp)
    196 {
    197 	struct ubuf *bp;
    198 	FINFO *fip;
    199 	struct inode *ip;
    200 	IFILE *ifp;
    201 	SEGSUM *ssp;
    202 
    203 	ip = VTOI(vp);
    204 
    205 	if (sp->seg_bytes_left < lfs_sb_getbsize(fs) ||
    206 	    sp->sum_bytes_left < FINFOSIZE(fs) + LFS_BLKPTRSIZE(fs))
    207 		(void) lfs_writeseg(fs, sp);
    208 
    209 	sp->sum_bytes_left -= FINFOSIZE(fs);
    210 	ssp = (SEGSUM *)sp->segsum;
    211 	lfs_ss_setnfinfo(fs, ssp, lfs_ss_getnfinfo(fs, ssp) + 1);
    212 
    213 	if (vp->v_uflag & VU_DIROP) {
    214 		lfs_ss_setflags(fs, ssp,
    215 				lfs_ss_getflags(fs, ssp) | (SS_DIROP | SS_CONT));
    216 	}
    217 
    218 	fip = sp->fip;
    219 	lfs_fi_setnblocks(fs, fip, 0);
    220 	lfs_fi_setino(fs, fip, ip->i_number);
    221 	LFS_IENTRY(ifp, fs, lfs_fi_getino(fs, fip), bp);
    222 	lfs_fi_setversion(fs, fip, lfs_if_getversion(fs, ifp));
    223 	brelse(bp, 0);
    224 
    225 	lfs_gather(fs, sp, vp, lfs_match_data);
    226 	lfs_gather(fs, sp, vp, lfs_match_indir);
    227 	lfs_gather(fs, sp, vp, lfs_match_dindir);
    228 	lfs_gather(fs, sp, vp, lfs_match_tindir);
    229 
    230 	fip = sp->fip;
    231 	if (lfs_fi_getnblocks(fs, fip) != 0) {
    232 		sp->fip = NEXT_FINFO(fs, fip);
    233 		lfs_blocks_fromfinfo(fs, &sp->start_lbp, sp->fip);
    234 	} else {
    235 		/* XXX shouldn't this update sp->fip? */
    236 		sp->sum_bytes_left += FINFOSIZE(fs);
    237 		lfs_ss_setnfinfo(fs, ssp, lfs_ss_getnfinfo(fs, ssp) - 1);
    238 	}
    239 }
    240 
    241 int
    242 lfs_writeinode(struct lfs * fs, struct segment * sp, struct inode * ip)
    243 {
    244 	struct ubuf *bp, *ibp;
    245 	union lfs_dinode *cdp;
    246 	IFILE *ifp;
    247 	SEGUSE *sup;
    248 	SEGSUM *ssp;
    249 	daddr_t daddr;
    250 	ino_t ino;
    251 	IINFO *iip;
    252 	int i, fsb = 0;
    253 	int redo_ifile = 0;
    254 	struct timespec ts;
    255 	int gotblk = 0;
    256 
    257 	/* Allocate a new inode block if necessary. */
    258 	if ((ip->i_number != LFS_IFILE_INUM || sp->idp == NULL) &&
    259 	    sp->ibp == NULL) {
    260 		/* Allocate a new segment if necessary. */
    261 		if (sp->seg_bytes_left < lfs_sb_getibsize(fs) ||
    262 		    sp->sum_bytes_left < LFS_BLKPTRSIZE(fs))
    263 			(void) lfs_writeseg(fs, sp);
    264 
    265 		/* Get next inode block. */
    266 		daddr = lfs_sb_getoffset(fs);
    267 		lfs_sb_addoffset(fs, lfs_btofsb(fs, lfs_sb_getibsize(fs)));
    268 		sp->ibp = *sp->cbpp++ =
    269 		    getblk(fs->lfs_devvp, LFS_FSBTODB(fs, daddr),
    270 		    lfs_sb_getibsize(fs));
    271 		sp->ibp->b_flags |= B_GATHERED;
    272 		gotblk++;
    273 
    274 		/* Zero out inode numbers */
    275 		for (i = 0; i < LFS_INOPB(fs); ++i) {
    276 			union lfs_dinode *tmpdip;
    277 
    278 			tmpdip = DINO_IN_BLOCK(fs, sp->ibp->b_data, i);
    279 			lfs_dino_setinumber(fs, tmpdip, 0);
    280 		}
    281 
    282 		++sp->start_bpp;
    283 		lfs_sb_subavail(fs, lfs_btofsb(fs, lfs_sb_getibsize(fs)));
    284 		/* Set remaining space counters. */
    285 		sp->seg_bytes_left -= lfs_sb_getibsize(fs);
    286 		sp->sum_bytes_left -= LFS_BLKPTRSIZE(fs);
    287 
    288 		/* Store the address in the segment summary. */
    289 		iip = NTH_IINFO(fs, sp->segsum, sp->ninodes / LFS_INOPB(fs));
    290 		lfs_ii_setblock(fs, iip, daddr);
    291 	}
    292 	/* Update the inode times and copy the inode onto the inode page. */
    293 	ts.tv_nsec = 0;
    294 	ts.tv_sec = write_time;
    295 	/* XXX kludge --- don't redirty the ifile just to put times on it */
    296 	if (ip->i_number != LFS_IFILE_INUM)
    297 		LFS_ITIMES(ip, &ts, &ts, &ts);
    298 
    299 	/*
    300 	 * If this is the Ifile, and we've already written the Ifile in this
    301 	 * partial segment, just overwrite it (it's not on disk yet) and
    302 	 * continue.
    303 	 *
    304 	 * XXX we know that the bp that we get the second time around has
    305 	 * already been gathered.
    306 	 */
    307 	if (ip->i_number == LFS_IFILE_INUM && sp->idp) {
    308 		lfs_copy_dinode(fs, sp->idp, ip->i_din);
    309 		ip->i_lfs_osize = lfs_dino_getsize(fs, ip->i_din);
    310 		return 0;
    311 	}
    312 	bp = sp->ibp;
    313 	cdp = DINO_IN_BLOCK(fs, bp->b_data, sp->ninodes % LFS_INOPB(fs));
    314 	lfs_copy_dinode(fs, cdp, ip->i_din);
    315 
    316 	/* If all blocks are goig to disk, update the "size on disk" */
    317 	ip->i_lfs_osize = lfs_dino_getsize(fs, ip->i_din);
    318 
    319 	if (ip->i_number == LFS_IFILE_INUM)	/* We know sp->idp == NULL */
    320 		sp->idp = DINO_IN_BLOCK(fs, bp->b_data, sp->ninodes % LFS_INOPB(fs));
    321 	if (gotblk) {
    322 		LFS_LOCK_BUF(bp);
    323 		assert(!(bp->b_flags & B_INVAL));
    324 		brelse(bp, 0);
    325 	}
    326 	/* Increment inode count in segment summary block. */
    327 	ssp = (SEGSUM *)sp->segsum;
    328 	lfs_ss_setninos(fs, ssp, lfs_ss_getninos(fs, ssp) + 1);
    329 
    330 	/* If this page is full, set flag to allocate a new page. */
    331 	if (++sp->ninodes % LFS_INOPB(fs) == 0)
    332 		sp->ibp = NULL;
    333 
    334 	/*
    335 	 * If updating the ifile, update the super-block.  Update the disk
    336 	 * address for this inode in the ifile.
    337 	 */
    338 	ino = ip->i_number;
    339 	if (ino == LFS_IFILE_INUM) {
    340 		daddr = lfs_sb_getidaddr(fs);
    341 		lfs_sb_setidaddr(fs, LFS_DBTOFSB(fs, bp->b_blkno));
    342 		sbdirty();
    343 	} else {
    344 		LFS_IENTRY(ifp, fs, ino, ibp);
    345 		daddr = lfs_if_getdaddr(fs, ifp);
    346 		lfs_if_setdaddr(fs, ifp, LFS_DBTOFSB(fs, bp->b_blkno) + fsb);
    347 		(void)LFS_BWRITE_LOG(ibp);	/* Ifile */
    348 	}
    349 
    350 	/*
    351 	 * Account the inode: it no longer belongs to its former segment,
    352 	 * though it will not belong to the new segment until that segment
    353 	 * is actually written.
    354 	 */
    355 	if (daddr != LFS_UNUSED_DADDR) {
    356 		u_int32_t oldsn = lfs_dtosn(fs, daddr);
    357 		LFS_SEGENTRY(sup, fs, oldsn, bp);
    358 		sup->su_nbytes -= DINOSIZE(fs);
    359 		redo_ifile =
    360 		    (ino == LFS_IFILE_INUM && !(bp->b_flags & B_GATHERED));
    361 		if (redo_ifile)
    362 			fs->lfs_flags |= LFS_IFDIRTY;
    363 		LFS_WRITESEGENTRY(sup, fs, oldsn, bp);	/* Ifile */
    364 	}
    365 	return redo_ifile;
    366 }
    367 
    368 int
    369 lfs_gatherblock(struct segment * sp, struct ubuf * bp)
    370 {
    371 	struct lfs *fs;
    372 	SEGSUM *ssp;
    373 	int version;
    374 	int j, blksinblk;
    375 
    376 	/*
    377 	 * If full, finish this segment.  We may be doing I/O, so
    378 	 * release and reacquire the splbio().
    379 	 */
    380 	fs = sp->fs;
    381 	blksinblk = howmany(bp->b_bcount, lfs_sb_getbsize(fs));
    382 	if (sp->sum_bytes_left < LFS_BLKPTRSIZE(fs) * blksinblk ||
    383 	    sp->seg_bytes_left < bp->b_bcount) {
    384 		lfs_updatemeta(sp);
    385 
    386 		version = lfs_fi_getversion(fs, sp->fip);
    387 		(void) lfs_writeseg(fs, sp);
    388 
    389 		lfs_fi_setversion(fs, sp->fip, version);
    390 		lfs_fi_setino(fs, sp->fip, VTOI(sp->vp)->i_number);
    391 		/* Add the current file to the segment summary. */
    392 		ssp = (SEGSUM *)sp->segsum;
    393 		lfs_ss_setnfinfo(fs, ssp, lfs_ss_getnfinfo(fs, ssp) + 1);
    394 		sp->sum_bytes_left -= FINFOSIZE(fs);
    395 
    396 		return 1;
    397 	}
    398 	/* Insert into the buffer list, update the FINFO block. */
    399 	bp->b_flags |= B_GATHERED;
    400 	/* bp->b_flags &= ~B_DONE; */
    401 
    402 	*sp->cbpp++ = bp;
    403 	for (j = 0; j < blksinblk; j++) {
    404 		unsigned bn;
    405 
    406 		bn = lfs_fi_getnblocks(fs, sp->fip);
    407 		lfs_fi_setnblocks(fs, sp->fip, bn + 1);
    408 		lfs_fi_setblock(fs, sp->fip, bn, bp->b_lblkno + j);
    409 	}
    410 
    411 	sp->sum_bytes_left -= LFS_BLKPTRSIZE(fs) * blksinblk;
    412 	sp->seg_bytes_left -= bp->b_bcount;
    413 	return 0;
    414 }
    415 
    416 int
    417 lfs_gather(struct lfs * fs, struct segment * sp, struct uvnode * vp, int (*match) (struct lfs *, struct ubuf *))
    418 {
    419 	struct ubuf *bp, *nbp;
    420 	int count = 0;
    421 
    422 	sp->vp = vp;
    423 loop:
    424 	for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
    425 		nbp = LIST_NEXT(bp, b_vnbufs);
    426 
    427 		assert(bp->b_flags & B_DELWRI);
    428 		if ((bp->b_flags & (B_BUSY | B_GATHERED)) || !match(fs, bp)) {
    429 			continue;
    430 		}
    431 		if (lfs_gatherblock(sp, bp)) {
    432 			goto loop;
    433 		}
    434 		count++;
    435 	}
    436 
    437 	lfs_updatemeta(sp);
    438 	sp->vp = NULL;
    439 	return count;
    440 }
    441 
    442 
    443 /*
    444  * Change the given block's address to ndaddr, finding its previous
    445  * location using ulfs_bmaparray().
    446  *
    447  * Account for this change in the segment table.
    448  */
    449 static void
    450 lfs_update_single(struct lfs * fs, struct segment * sp, daddr_t lbn,
    451     daddr_t ndaddr, int size)
    452 {
    453 	SEGUSE *sup;
    454 	struct ubuf *bp;
    455 	struct indir a[ULFS_NIADDR + 2], *ap;
    456 	struct inode *ip;
    457 	struct uvnode *vp;
    458 	daddr_t daddr, ooff;
    459 	int num, error;
    460 	int osize;
    461 	int frags, ofrags;
    462 
    463 	vp = sp->vp;
    464 	ip = VTOI(vp);
    465 
    466 	error = ulfs_bmaparray(fs, vp, lbn, &daddr, a, &num);
    467 	if (error)
    468 		errx(EXIT_FAILURE, "%s: ulfs_bmaparray returned %d looking up lbn %"
    469 		    PRId64 "", __func__, error, lbn);
    470 	if (daddr > 0)
    471 		daddr = LFS_DBTOFSB(fs, daddr);
    472 
    473 	frags = lfs_numfrags(fs, size);
    474 	switch (num) {
    475 	case 0:
    476 		ooff = lfs_dino_getdb(fs, ip->i_din, lbn);
    477 		if (ooff == UNWRITTEN)
    478 			lfs_dino_setblocks(fs, ip->i_din,
    479 			    lfs_dino_getblocks(fs, ip->i_din) + frags);
    480 		else {
    481 			/* possible fragment truncation or extension */
    482 			ofrags = lfs_btofsb(fs, ip->i_lfs_fragsize[lbn]);
    483 			lfs_dino_setblocks(fs, ip->i_din,
    484 			    lfs_dino_getblocks(fs, ip->i_din) + (frags - ofrags));
    485 		}
    486 		lfs_dino_setdb(fs, ip->i_din, lbn, ndaddr);
    487 		break;
    488 	case 1:
    489 		ooff = lfs_dino_getib(fs, ip->i_din, a[0].in_off);
    490 		if (ooff == UNWRITTEN)
    491 			lfs_dino_setblocks(fs, ip->i_din,
    492 			    lfs_dino_getblocks(fs, ip->i_din) + frags);
    493 		lfs_dino_setib(fs, ip->i_din, a[0].in_off, ndaddr);
    494 		break;
    495 	default:
    496 		ap = &a[num - 1];
    497 		if (bread(vp, ap->in_lbn, lfs_sb_getbsize(fs), 0, &bp))
    498 			errx(EXIT_FAILURE, "%s: bread bno %" PRId64, __func__,
    499 			    ap->in_lbn);
    500 
    501 		ooff = lfs_iblock_get(fs, bp->b_data, ap->in_off);
    502 		if (ooff == UNWRITTEN)
    503 			lfs_dino_setblocks(fs, ip->i_din,
    504 			    lfs_dino_getblocks(fs, ip->i_din) + frags);
    505 		lfs_iblock_set(fs, bp->b_data, ap->in_off, ndaddr);
    506 		(void) VOP_BWRITE(bp);
    507 	}
    508 
    509 	/*
    510 	 * Update segment usage information, based on old size
    511 	 * and location.
    512 	 */
    513 	if (daddr > 0) {
    514 		u_int32_t oldsn = lfs_dtosn(fs, daddr);
    515 		if (lbn >= 0 && lbn < ULFS_NDADDR)
    516 			osize = ip->i_lfs_fragsize[lbn];
    517 		else
    518 			osize = lfs_sb_getbsize(fs);
    519 		LFS_SEGENTRY(sup, fs, oldsn, bp);
    520 		sup->su_nbytes -= osize;
    521 		if (!(bp->b_flags & B_GATHERED))
    522 			fs->lfs_flags |= LFS_IFDIRTY;
    523 		LFS_WRITESEGENTRY(sup, fs, oldsn, bp);
    524 	}
    525 	/*
    526 	 * Now that this block has a new address, and its old
    527 	 * segment no longer owns it, we can forget about its
    528 	 * old size.
    529 	 */
    530 	if (lbn >= 0 && lbn < ULFS_NDADDR)
    531 		ip->i_lfs_fragsize[lbn] = size;
    532 }
    533 
    534 /*
    535  * Update the metadata that points to the blocks listed in the FINFO
    536  * array.
    537  */
    538 void
    539 lfs_updatemeta(struct segment * sp)
    540 {
    541 	struct ubuf *sbp;
    542 	struct lfs *fs;
    543 	struct uvnode *vp;
    544 	daddr_t lbn;
    545 	int i, nblocks, num;
    546 	int frags;
    547 	int bytesleft, size;
    548 	union lfs_blocks tmpptr;
    549 
    550 	fs = sp->fs;
    551 	vp = sp->vp;
    552 
    553 	/*
    554 	 * This code was cutpasted from the kernel. See the
    555 	 * corresponding comment in lfs_segment.c.
    556 	 */
    557 #if 0
    558 	nblocks = &sp->fip->fi_blocks[sp->fip->fi_nblocks] - sp->start_lbp;
    559 #else
    560 	lfs_blocks_fromvoid(fs, &tmpptr, (void *)NEXT_FINFO(fs, sp->fip));
    561 	nblocks = lfs_blocks_sub(fs, &tmpptr, &sp->start_lbp);
    562 	//nblocks_orig = nblocks;
    563 #endif
    564 
    565 	if (vp == NULL || nblocks == 0)
    566 		return;
    567 
    568 	/*
    569 	 * This count may be high due to oversize blocks from lfs_gop_write.
    570 	 * Correct for this. (XXX we should be able to keep track of these.)
    571 	 */
    572 	for (i = 0; i < nblocks; i++) {
    573 		if (sp->start_bpp[i] == NULL) {
    574 			printf("nblocks = %d, not %d\n", i, nblocks);
    575 			nblocks = i;
    576 			break;
    577 		}
    578 		num = howmany(sp->start_bpp[i]->b_bcount, lfs_sb_getbsize(fs));
    579 		nblocks -= num - 1;
    580 	}
    581 
    582 	/*
    583 	 * Sort the blocks.
    584 	 */
    585 	lfs_shellsort(fs, sp->start_bpp, &sp->start_lbp, nblocks, lfs_sb_getbsize(fs));
    586 
    587 	/*
    588 	 * Record the length of the last block in case it's a fragment.
    589 	 * If there are indirect blocks present, they sort last.  An
    590 	 * indirect block will be lfs_bsize and its presence indicates
    591 	 * that you cannot have fragments.
    592 	 */
    593 	lfs_fi_setlastlength(fs, sp->fip, ((sp->start_bpp[nblocks - 1]->b_bcount - 1) &
    594 	    lfs_sb_getbmask(fs)) + 1);
    595 
    596 	/*
    597 	 * Assign disk addresses, and update references to the logical
    598 	 * block and the segment usage information.
    599 	 */
    600 	for (i = nblocks; i--; ++sp->start_bpp) {
    601 		sbp = *sp->start_bpp;
    602 		lbn = lfs_blocks_get(fs, &sp->start_lbp, 0);
    603 
    604 		sbp->b_blkno = LFS_FSBTODB(fs, lfs_sb_getoffset(fs));
    605 
    606 		/*
    607 		 * If we write a frag in the wrong place, the cleaner won't
    608 		 * be able to correctly identify its size later, and the
    609 		 * segment will be uncleanable.	 (Even worse, it will assume
    610 		 * that the indirect block that actually ends the list
    611 		 * is of a smaller size!)
    612 		 */
    613 		if ((sbp->b_bcount & lfs_sb_getbmask(fs)) && i != 0)
    614 			errx(EXIT_FAILURE, "%s: fragment is not last block", __func__);
    615 
    616 		/*
    617 		 * For each subblock in this possibly oversized block,
    618 		 * update its address on disk.
    619 		 */
    620 		for (bytesleft = sbp->b_bcount; bytesleft > 0;
    621 		    bytesleft -= lfs_sb_getbsize(fs)) {
    622 			size = MIN(bytesleft, lfs_sb_getbsize(fs));
    623 			frags = lfs_numfrags(fs, size);
    624 			lbn = lfs_blocks_get(fs, &sp->start_lbp, 0);
    625 			lfs_blocks_inc(fs, &sp->start_lbp);
    626 			lfs_update_single(fs, sp, lbn, lfs_sb_getoffset(fs), size);
    627 			lfs_sb_addoffset(fs, frags);
    628 		}
    629 
    630 	}
    631 }
    632 
    633 /*
    634  * Start a new segment.
    635  */
    636 int
    637 lfs_initseg(struct lfs * fs)
    638 {
    639 	struct segment *sp;
    640 	SEGUSE *sup;
    641 	SEGSUM *ssp;
    642 	struct ubuf *bp, *sbp;
    643 	int repeat;
    644 
    645 	sp = fs->lfs_sp;
    646 
    647 	repeat = 0;
    648 
    649 	/* Advance to the next segment. */
    650 	if (!LFS_PARTIAL_FITS(fs)) {
    651 		/* lfs_avail eats the remaining space */
    652 		lfs_sb_subavail(fs, lfs_sb_getfsbpseg(fs) - (lfs_sb_getoffset(fs) -
    653 		    lfs_sb_getcurseg(fs)));
    654 		lfs_newseg(fs);
    655 		repeat = 1;
    656 		lfs_sb_setoffset(fs, lfs_sb_getcurseg(fs));
    657 
    658 		sp->seg_number = lfs_dtosn(fs, lfs_sb_getcurseg(fs));
    659 		sp->seg_bytes_left = lfs_fsbtob(fs, lfs_sb_getfsbpseg(fs));
    660 
    661 		/*
    662 		 * If the segment contains a superblock, update the offset
    663 		 * and summary address to skip over it.
    664 		 */
    665 		LFS_SEGENTRY(sup, fs, sp->seg_number, bp);
    666 		if (sup->su_flags & SEGUSE_SUPERBLOCK) {
    667 			lfs_sb_addoffset(fs, lfs_btofsb(fs, LFS_SBPAD));
    668 			sp->seg_bytes_left -= LFS_SBPAD;
    669 		}
    670 		brelse(bp, 0);
    671 		/* Segment zero could also contain the labelpad */
    672 		if (lfs_sb_getversion(fs) > 1 && sp->seg_number == 0 &&
    673 		    lfs_sb_gets0addr(fs) < lfs_btofsb(fs, LFS_LABELPAD)) {
    674 			lfs_sb_addoffset(fs, lfs_btofsb(fs, LFS_LABELPAD) - lfs_sb_gets0addr(fs));
    675 			sp->seg_bytes_left -= LFS_LABELPAD - lfs_fsbtob(fs, lfs_sb_gets0addr(fs));
    676 		}
    677 	} else {
    678 		sp->seg_number = lfs_dtosn(fs, lfs_sb_getcurseg(fs));
    679 		sp->seg_bytes_left = lfs_fsbtob(fs, lfs_sb_getfsbpseg(fs) -
    680 		    (lfs_sb_getoffset(fs) - lfs_sb_getcurseg(fs)));
    681 	}
    682 	lfs_sb_setlastpseg(fs, lfs_sb_getoffset(fs));
    683 
    684 	sp->fs = fs;
    685 	sp->ibp = NULL;
    686 	sp->idp = NULL;
    687 	sp->ninodes = 0;
    688 	sp->ndupino = 0;
    689 
    690 	/* Get a new buffer for SEGSUM and enter it into the buffer list. */
    691 	sp->cbpp = sp->bpp;
    692 	sbp = *sp->cbpp = getblk(fs->lfs_devvp,
    693 	    LFS_FSBTODB(fs, lfs_sb_getoffset(fs)), lfs_sb_getsumsize(fs));
    694 	sp->segsum = sbp->b_data;
    695 	memset(sp->segsum, 0, lfs_sb_getsumsize(fs));
    696 	sp->start_bpp = ++sp->cbpp;
    697 	lfs_sb_addoffset(fs, lfs_btofsb(fs, lfs_sb_getsumsize(fs)));
    698 
    699 	/* Set point to SEGSUM, initialize it. */
    700 	ssp = sp->segsum;
    701 	lfs_ss_setnext(fs, ssp, lfs_sb_getnextseg(fs));
    702 	lfs_ss_setnfinfo(fs, ssp, 0);
    703 	lfs_ss_setninos(fs, ssp, 0);
    704 	lfs_ss_setmagic(fs, ssp, SS_MAGIC);
    705 
    706 	/* Set pointer to first FINFO, initialize it. */
    707 	sp->fip = SEGSUM_FINFOBASE(fs, ssp);
    708 	lfs_fi_setnblocks(fs, sp->fip, 0);
    709 	lfs_blocks_fromfinfo(fs, &sp->start_lbp, sp->fip);
    710 	lfs_fi_setlastlength(fs, sp->fip, 0);
    711 
    712 	sp->seg_bytes_left -= lfs_sb_getsumsize(fs);
    713 	sp->sum_bytes_left = lfs_sb_getsumsize(fs) - SEGSUM_SIZE(fs);
    714 
    715 	LFS_LOCK_BUF(sbp);
    716 	brelse(sbp, 0);
    717 	return repeat;
    718 }
    719 
    720 /*
    721  * Return the next segment to write.
    722  */
    723 void
    724 lfs_newseg(struct lfs * fs)
    725 {
    726 	CLEANERINFO *cip;
    727 	SEGUSE *sup;
    728 	struct ubuf *bp;
    729 	int curseg, isdirty, sn;
    730 
    731 	LFS_SEGENTRY(sup, fs, lfs_dtosn(fs, lfs_sb_getnextseg(fs)), bp);
    732 	sup->su_flags |= SEGUSE_DIRTY | SEGUSE_ACTIVE;
    733 	sup->su_nbytes = 0;
    734 	sup->su_nsums = 0;
    735 	sup->su_ninos = 0;
    736 	LFS_WRITESEGENTRY(sup, fs, lfs_dtosn(fs, lfs_sb_getnextseg(fs)), bp);
    737 
    738 	LFS_CLEANERINFO(cip, fs, bp);
    739 	lfs_ci_shiftcleantodirty(fs, cip, 1);
    740 	lfs_sb_setnclean(fs, lfs_ci_getclean(fs, cip));
    741 	LFS_SYNC_CLEANERINFO(cip, fs, bp, 1);
    742 
    743 	lfs_sb_setlastseg(fs, lfs_sb_getcurseg(fs));
    744 	lfs_sb_setcurseg(fs, lfs_sb_getnextseg(fs));
    745 	for (sn = curseg = lfs_dtosn(fs, lfs_sb_getcurseg(fs)) + lfs_sb_getinterleave(fs);;) {
    746 		sn = (sn + 1) % lfs_sb_getnseg(fs);
    747 		if (sn == curseg)
    748 			errx(EXIT_FAILURE, "%s: no clean segments", __func__);
    749 		LFS_SEGENTRY(sup, fs, sn, bp);
    750 		isdirty = sup->su_flags & SEGUSE_DIRTY;
    751 		brelse(bp, 0);
    752 
    753 		if (!isdirty)
    754 			break;
    755 	}
    756 
    757 	++fs->lfs_nactive;
    758 	lfs_sb_setnextseg(fs, lfs_sntod(fs, sn));
    759 }
    760 
    761 
    762 int
    763 lfs_writeseg(struct lfs * fs, struct segment * sp)
    764 {
    765 	struct ubuf **bpp, *bp;
    766 	SEGUSE *sup;
    767 	SEGSUM *ssp;
    768 	char *datap, *dp;
    769 	int i;
    770 	int do_again, nblocks, byteoffset;
    771 	size_t el_size;
    772 	u_short ninos;
    773 	size_t sumstart;
    774 	struct uvnode *devvp;
    775 
    776 	/*
    777 	 * If there are no buffers other than the segment summary to write
    778 	 * and it is not a checkpoint, don't do anything.  On a checkpoint,
    779 	 * even if there aren't any buffers, you need to write the superblock.
    780 	 */
    781 	nblocks = sp->cbpp - sp->bpp;
    782 #if 0
    783 	printf("write %d blocks at 0x%x\n",
    784 		nblocks, (int)LFS_DBTOFSB(fs, (*sp->bpp)->b_blkno));
    785 #endif
    786 	if (nblocks == 1)
    787 		return 0;
    788 
    789 	devvp = fs->lfs_devvp;
    790 
    791 	/* Update the segment usage information. */
    792 	LFS_SEGENTRY(sup, fs, sp->seg_number, bp);
    793 	sup->su_flags |= SEGUSE_DIRTY | SEGUSE_ACTIVE;
    794 
    795 	/* Loop through all blocks, except the segment summary. */
    796 	for (bpp = sp->bpp; ++bpp < sp->cbpp;) {
    797 		if ((*bpp)->b_vp != devvp) {
    798 			sup->su_nbytes += (*bpp)->b_bcount;
    799 		}
    800 		assert(lfs_dtosn(fs, LFS_DBTOFSB(fs, (*bpp)->b_blkno)) == sp->seg_number);
    801 	}
    802 
    803 	ssp = (SEGSUM *) sp->segsum;
    804 	lfs_ss_setflags(fs, ssp, lfs_ss_getflags(fs, ssp) | SS_RFW);
    805 
    806 	ninos = (lfs_ss_getninos(fs, ssp) + LFS_INOPB(fs) - 1) / LFS_INOPB(fs);
    807 	sup->su_nbytes += lfs_ss_getninos(fs, ssp) * DINOSIZE(fs);
    808 
    809 	if (lfs_sb_getversion(fs) == 1)
    810 		sup->su_olastmod = write_time;
    811 	else
    812 		sup->su_lastmod = write_time;
    813 	sup->su_ninos += ninos;
    814 	++sup->su_nsums;
    815 	lfs_sb_adddmeta(fs, (lfs_btofsb(fs, lfs_sb_getsumsize(fs)) + lfs_btofsb(fs, ninos *
    816 		lfs_sb_getibsize(fs))));
    817 	lfs_sb_subavail(fs, lfs_btofsb(fs, lfs_sb_getsumsize(fs)));
    818 
    819 	do_again = !(bp->b_flags & B_GATHERED);
    820 	LFS_WRITESEGENTRY(sup, fs, sp->seg_number, bp);	/* Ifile */
    821 
    822 	/*
    823 	 * Compute checksum across data and then across summary; the first
    824 	 * block (the summary block) is skipped.  Set the create time here
    825 	 * so that it's guaranteed to be later than the inode mod times.
    826 	 */
    827 	if (lfs_sb_getversion(fs) == 1)
    828 		el_size = sizeof(u_long);
    829 	else
    830 		el_size = sizeof(u_int32_t);
    831 	datap = dp = emalloc(nblocks * el_size);
    832 	for (bpp = sp->bpp, i = nblocks - 1; i--;) {
    833 		++bpp;
    834 		/* Loop through gop_write cluster blocks */
    835 		for (byteoffset = 0; byteoffset < (*bpp)->b_bcount;
    836 		    byteoffset += lfs_sb_getbsize(fs)) {
    837 			memcpy(dp, (*bpp)->b_data + byteoffset, el_size);
    838 			dp += el_size;
    839 		}
    840 		bremfree(*bpp);
    841 		(*bpp)->b_flags |= B_BUSY;
    842 	}
    843 	if (lfs_sb_getversion(fs) == 1)
    844 		lfs_ss_setocreate(fs, ssp, write_time);
    845 	else {
    846 		lfs_ss_setcreate(fs, ssp, write_time);
    847 		lfs_sb_addserial(fs, 1);
    848 		lfs_ss_setserial(fs, ssp, lfs_sb_getserial(fs));
    849 		lfs_ss_setident(fs, ssp, lfs_sb_getident(fs));
    850 	}
    851 	/* Set the summary block busy too */
    852 	bremfree(*(sp->bpp));
    853 	(*(sp->bpp))->b_flags |= B_BUSY;
    854 
    855 	lfs_ss_setdatasum(fs, ssp, cksum(datap, (nblocks - 1) * el_size));
    856 	sumstart = lfs_ss_getsumstart(fs);
    857 	lfs_ss_setsumsum(fs, ssp,
    858 	    cksum((char *)ssp + sumstart, lfs_sb_getsumsize(fs) - sumstart));
    859 	free(datap);
    860 	datap = dp = NULL;
    861 	lfs_sb_subbfree(fs, (lfs_btofsb(fs, ninos * lfs_sb_getibsize(fs)) +
    862 	    lfs_btofsb(fs, lfs_sb_getsumsize(fs))));
    863 
    864 	if (devvp == NULL)
    865 		errx(EXIT_FAILURE, "devvp is NULL");
    866 	for (bpp = sp->bpp, i = nblocks; i; bpp++, i--) {
    867 		bp = *bpp;
    868 #if 0
    869 		printf("i = %d, bp = %p, flags %lx, bn = %" PRIx64 "\n",
    870 		       nblocks - i, bp, bp->b_flags, bp->b_blkno);
    871 		printf("  vp = %p\n", bp->b_vp);
    872 		if (bp->b_vp != fs->lfs_devvp)
    873 			printf("  ino = %d lbn = %" PRId64 "\n",
    874 			       VTOI(bp->b_vp)->i_number, bp->b_lblkno);
    875 #endif
    876 		if (bp->b_vp == fs->lfs_devvp)
    877 			written_dev += bp->b_bcount;
    878 		else {
    879 			if (bp->b_lblkno >= 0)
    880 				written_data += bp->b_bcount;
    881 			else
    882 				written_indir += bp->b_bcount;
    883 		}
    884 		bp->b_flags &= ~(B_DELWRI | B_READ | B_GATHERED | B_ERROR |
    885 				 B_LOCKED);
    886 		bwrite(bp);
    887 		written_bytes += bp->b_bcount;
    888 	}
    889 	written_inodes += ninos;
    890 
    891 	return (lfs_initseg(fs) || do_again);
    892 }
    893 
    894 /*
    895  * Our own copy of shellsort.  XXX use qsort or heapsort.
    896  */
    897 static void
    898 lfs_shellsort(struct lfs *fs,
    899 	      struct ubuf ** bp_array, union lfs_blocks *lb_array, int nmemb, int size)
    900 {
    901 	static int __rsshell_increments[] = {4, 1, 0};
    902 	int incr, *incrp, t1, t2;
    903 	struct ubuf *bp_temp;
    904 
    905 	for (incrp = __rsshell_increments; (incr = *incrp++) != 0;)
    906 		for (t1 = incr; t1 < nmemb; ++t1)
    907 			for (t2 = t1 - incr; t2 >= 0;)
    908 				if ((u_int32_t) bp_array[t2]->b_lblkno >
    909 				    (u_int32_t) bp_array[t2 + incr]->b_lblkno) {
    910 					bp_temp = bp_array[t2];
    911 					bp_array[t2] = bp_array[t2 + incr];
    912 					bp_array[t2 + incr] = bp_temp;
    913 					t2 -= incr;
    914 				} else
    915 					break;
    916 
    917 	/* Reform the list of logical blocks */
    918 	incr = 0;
    919 	for (t1 = 0; t1 < nmemb; t1++) {
    920 		for (t2 = 0; t2 * size < bp_array[t1]->b_bcount; t2++) {
    921 			lfs_blocks_set(fs, lb_array, incr++,
    922 				       bp_array[t1]->b_lblkno + t2);
    923 		}
    924 	}
    925 }
    926 
    927 
    928 /*
    929  * lfs_seglock --
    930  *	Single thread the segment writer.
    931  */
    932 int
    933 lfs_seglock(struct lfs * fs, unsigned long flags)
    934 {
    935 	struct segment *sp;
    936 	size_t allocsize;
    937 
    938 	if (fs->lfs_seglock) {
    939 		++fs->lfs_seglock;
    940 		fs->lfs_sp->seg_flags |= flags;
    941 		return 0;
    942 	}
    943 	fs->lfs_seglock = 1;
    944 
    945 	sp = fs->lfs_sp = emalloc(sizeof(*sp));
    946 	allocsize = lfs_sb_getssize(fs) * sizeof(struct ubuf *);
    947 	sp->bpp = emalloc(allocsize);
    948 	if (!sp->bpp)
    949 		err(!preen, "Could not allocate %zu bytes", allocsize);
    950 	sp->seg_flags = flags;
    951 	sp->vp = NULL;
    952 	sp->seg_iocount = 0;
    953 	(void) lfs_initseg(fs);
    954 
    955 	return 0;
    956 }
    957 
    958 /*
    959  * lfs_segunlock --
    960  *	Single thread the segment writer.
    961  */
    962 void
    963 lfs_segunlock(struct lfs * fs)
    964 {
    965 	struct segment *sp;
    966 	struct ubuf *bp;
    967 
    968 	sp = fs->lfs_sp;
    969 
    970 	if (fs->lfs_seglock == 1) {
    971 		if (sp->bpp != sp->cbpp) {
    972 			/* Free allocated segment summary */
    973 			lfs_sb_suboffset(fs, lfs_btofsb(fs, lfs_sb_getsumsize(fs)));
    974 			bp = *sp->bpp;
    975 			bremfree(bp);
    976 			bp->b_flags |= B_DONE | B_INVAL;
    977 			bp->b_flags &= ~B_DELWRI;
    978 			reassignbuf(bp, bp->b_vp);
    979 			bp->b_flags |= B_BUSY; /* XXX */
    980 			brelse(bp, 0);
    981 		} else
    982 			printf("unlock to 0 with no summary");
    983 
    984 		free(sp->bpp);
    985 		sp->bpp = NULL;
    986 		free(sp);
    987 		fs->lfs_sp = NULL;
    988 
    989 		fs->lfs_nactive = 0;
    990 
    991 		/* Since we *know* everything's on disk, write both sbs */
    992 		lfs_writesuper(fs, lfs_sb_getsboff(fs, 0));
    993 		lfs_writesuper(fs, lfs_sb_getsboff(fs, 1));
    994 
    995 		--fs->lfs_seglock;
    996 		fs->lfs_lockpid = 0;
    997 	} else if (fs->lfs_seglock == 0) {
    998 		errx(EXIT_FAILURE, "Seglock not held");
    999 	} else {
   1000 		--fs->lfs_seglock;
   1001 	}
   1002 }
   1003 
   1004 int
   1005 lfs_writevnodes(struct lfs *fs, struct segment *sp, int op)
   1006 {
   1007 	struct inode *ip;
   1008 	struct uvnode *vp;
   1009 	int inodes_written = 0;
   1010 
   1011 	LIST_FOREACH(vp, &vnodelist, v_mntvnodes) {
   1012 		if (vp->v_bmap_op != lfs_vop_bmap)
   1013 			continue;
   1014 
   1015 		ip = VTOI(vp);
   1016 
   1017 		if ((op == VN_DIROP && !(vp->v_uflag & VU_DIROP)) ||
   1018 		    (op != VN_DIROP && (vp->v_uflag & VU_DIROP))) {
   1019 			continue;
   1020 		}
   1021 		/*
   1022 		 * Write the inode/file if dirty and it's not the IFILE.
   1023 		 */
   1024 		if (ip->i_state & IN_ALLMOD || !LIST_EMPTY(&vp->v_dirtyblkhd)) {
   1025 			if (ip->i_number != LFS_IFILE_INUM)
   1026 				lfs_writefile(fs, sp, vp);
   1027 			(void) lfs_writeinode(fs, sp, ip);
   1028 			inodes_written++;
   1029 		}
   1030 	}
   1031 	return inodes_written;
   1032 }
   1033 
   1034 void
   1035 lfs_writesuper(struct lfs *fs, daddr_t daddr)
   1036 {
   1037 	struct ubuf *bp;
   1038 
   1039 	/* Set timestamp of this version of the superblock */
   1040 	if (lfs_sb_getversion(fs) == 1)
   1041 		lfs_sb_setotstamp(fs, write_time);
   1042 	lfs_sb_settstamp(fs, write_time);
   1043 
   1044 	__CTASSERT(sizeof(struct dlfs) == sizeof(struct dlfs64));
   1045 
   1046 	/* Checksum the superblock and copy it into a buffer. */
   1047 	lfs_sb_setcksum(fs, lfs_sb_cksum(fs));
   1048 	assert(daddr > 0);
   1049 	bp = getblk(fs->lfs_devvp, LFS_FSBTODB(fs, daddr), LFS_SBPAD);
   1050 	memcpy(bp->b_data, &fs->lfs_dlfs_u, sizeof(struct dlfs));
   1051 	memset(bp->b_data + sizeof(struct dlfs), 0,
   1052 	    LFS_SBPAD - sizeof(struct dlfs));
   1053 
   1054 	bwrite(bp);
   1055 }
   1056