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lfs_alloc.c revision 1.49
      1 /*	$NetBSD: lfs_alloc.c,v 1.49 2001/09/15 20:36:43 chs Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1999, 2000 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 (at) 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_alloc.c	8.4 (Berkeley) 1/4/94
     71  */
     72 
     73 #if defined(_KERNEL_OPT)
     74 #include "opt_quota.h"
     75 #endif
     76 
     77 #include <sys/param.h>
     78 #include <sys/systm.h>
     79 #include <sys/kernel.h>
     80 #include <sys/buf.h>
     81 #include <sys/vnode.h>
     82 #include <sys/syslog.h>
     83 #include <sys/mount.h>
     84 #include <sys/malloc.h>
     85 #include <sys/pool.h>
     86 
     87 #include <ufs/ufs/quota.h>
     88 #include <ufs/ufs/inode.h>
     89 #include <ufs/ufs/ufsmount.h>
     90 #include <ufs/ufs/ufs_extern.h>
     91 
     92 #include <ufs/lfs/lfs.h>
     93 #include <ufs/lfs/lfs_extern.h>
     94 
     95 extern int lfs_dirvcount;
     96 extern struct lock ufs_hashlock;
     97 
     98 static int extend_ifile(struct lfs *, struct ucred *);
     99 static int lfs_ialloc(struct lfs *, struct vnode *, ino_t, int, struct vnode **);
    100 
    101 /*
    102  * Allocate a particular inode with a particular version number, freeing
    103  * any previous versions of this inode that may have gone before.
    104  * Used by the roll-forward code.
    105  *
    106  * XXX this function does not have appropriate locking to be used on a live fs;
    107  * XXX but something similar could probably be used for an "undelete" call.
    108  */
    109 int
    110 lfs_rf_valloc(struct lfs *fs, ino_t ino, int version, struct proc *p,
    111 	      struct vnode **vpp)
    112 {
    113 	IFILE *ifp;
    114 	struct buf *bp, *cbp;
    115 	struct vnode *vp;
    116 	struct inode *ip;
    117 	ino_t tino, oldnext;
    118 	int error;
    119 	CLEANERINFO *cip;
    120 
    121 	/*
    122 	 * First, just try a vget. If the version number is the one we want,
    123 	 * we don't have to do anything else.  If the version number is wrong,
    124 	 * take appropriate action.
    125 	 */
    126 	error = VFS_VGET(fs->lfs_ivnode->v_mount, ino, &vp);
    127 	if (error == 0) {
    128 		/* printf("lfs_rf_valloc[1]: ino %d vp %p\n", ino, vp); */
    129 
    130 		*vpp = vp;
    131 		ip = VTOI(vp);
    132 		if (ip->i_ffs_gen == version)
    133 			return 0;
    134 		else if (ip->i_ffs_gen < version) {
    135 			VOP_TRUNCATE(vp, (off_t)0, 0, NOCRED, p);
    136 			ip->i_ffs_gen = version;
    137 			LFS_SET_UINO(ip, IN_CHANGE | IN_MODIFIED | IN_UPDATE);
    138 			return 0;
    139 		} else {
    140 			/* printf("ino %d: asked for version %d but got %d\n",
    141 			       ino, version, ip->i_ffs_gen); */
    142 			vput(vp);
    143 			*vpp = NULLVP;
    144 			return EEXIST;
    145 		}
    146 	}
    147 
    148 	/*
    149 	 * The inode is not in use.  Find it on the free list.
    150 	 */
    151 	/* If the Ifile is too short to contain this inum, extend it */
    152 	while (VTOI(fs->lfs_ivnode)->i_ffs_size <= (ino /
    153 		fs->lfs_ifpb + fs->lfs_cleansz + fs->lfs_segtabsz)
    154 		<< fs->lfs_bshift) {
    155 		extend_ifile(fs, NOCRED);
    156 	}
    157 
    158 	LFS_IENTRY(ifp, fs, ino, bp);
    159 	oldnext = ifp->if_nextfree;
    160 	ifp->if_version = version;
    161 	brelse(bp);
    162 
    163 	LFS_GET_HEADFREE(fs, cip, cbp, &ino);
    164 	if (ino) {
    165 		LFS_PUT_HEADFREE(fs, cip, cbp, oldnext);
    166 	} else {
    167 		tino = ino;
    168 		while(1) {
    169 			LFS_IENTRY(ifp, fs, tino, bp);
    170 			if (ifp->if_nextfree == ino ||
    171 			    ifp->if_nextfree == LFS_UNUSED_INUM)
    172 				break;
    173 			tino = ifp->if_nextfree;
    174 			brelse(bp);
    175 		}
    176 		if (ifp->if_nextfree == LFS_UNUSED_INUM) {
    177 			brelse(bp);
    178 			return ENOENT;
    179 		}
    180 		ifp->if_nextfree = oldnext;
    181 		VOP_BWRITE(bp);
    182 	}
    183 
    184 	error = lfs_ialloc(fs, fs->lfs_ivnode, ino, version, &vp);
    185 	if (error == 0) {
    186 		/*
    187 		 * Make it VREG so we can put blocks on it.  We will change
    188 		 * this later if it turns out to be some other kind of file.
    189 		 */
    190 		ip = VTOI(vp);
    191 		ip->i_ffs_mode = IFREG;
    192 		ip->i_ffs_nlink = 1;
    193 		ip->i_ffs_effnlink = 1;
    194 		ufs_vinit(vp->v_mount, lfs_specop_p, lfs_fifoop_p, &vp);
    195 		ip = VTOI(vp);
    196 
    197 		/* printf("lfs_rf_valloc: ino %d vp %p\n", ino, vp); */
    198 
    199 		/* The dirop-nature of this vnode is past */
    200 		(void)lfs_vunref(vp);
    201 		--lfs_dirvcount;
    202 		vp->v_flag &= ~VDIROP;
    203 		--fs->lfs_nadirop;
    204 		ip->i_flag &= ~IN_ADIROP;
    205 	}
    206 	*vpp = vp;
    207 	return error;
    208 }
    209 
    210 static int
    211 extend_ifile(struct lfs *fs, struct ucred *cred)
    212 {
    213 	struct vnode *vp;
    214 	struct inode *ip;
    215 	IFILE *ifp;
    216 	IFILE_V1 *ifp_v1;
    217 	struct buf *bp, *cbp;
    218 	int error;
    219 	ufs_daddr_t i, blkno, max;
    220 	ino_t oldlast;
    221 	CLEANERINFO *cip;
    222 
    223 	vp = fs->lfs_ivnode;
    224 	(void)lfs_vref(vp);
    225 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
    226 	ip = VTOI(vp);
    227 	blkno = lblkno(fs, ip->i_ffs_size);
    228 	if ((error = VOP_BALLOC(vp, ip->i_ffs_size, fs->lfs_bsize, cred, 0,
    229 				&bp)) != 0) {
    230 		VOP_UNLOCK(vp, 0);
    231 		lfs_vunref(vp);
    232 		return (error);
    233 	}
    234 	ip->i_ffs_size += fs->lfs_bsize;
    235 	uvm_vnp_setsize(vp, ip->i_ffs_size);
    236 	VOP_UNLOCK(vp, 0);
    237 
    238 	i = (blkno - fs->lfs_segtabsz - fs->lfs_cleansz) *
    239 		fs->lfs_ifpb;
    240 	LFS_GET_HEADFREE(fs, cip, cbp, &oldlast);
    241 	LFS_PUT_HEADFREE(fs, cip, cbp, i);
    242 #ifdef DIAGNOSTIC
    243 	if(fs->lfs_free == LFS_UNUSED_INUM)
    244 		panic("inode 0 allocated [2]");
    245 #endif /* DIAGNOSTIC */
    246 	max = i + fs->lfs_ifpb;
    247 	/* printf("extend ifile for ino %d--%d\n", i, max); */
    248 
    249 	if(fs->lfs_version == 1) {
    250 		for (ifp_v1 = (IFILE_V1 *)bp->b_data; i < max; ++ifp_v1) {
    251 			ifp_v1->if_version = 1;
    252 			ifp_v1->if_daddr = LFS_UNUSED_DADDR;
    253 			ifp_v1->if_nextfree = ++i;
    254 		}
    255 		ifp_v1--;
    256 		ifp_v1->if_nextfree = oldlast;
    257 	} else {
    258 		for (ifp = (IFILE *)bp->b_data; i < max; ++ifp) {
    259 			ifp->if_version = 1;
    260 			ifp->if_daddr = LFS_UNUSED_DADDR;
    261 			ifp->if_nextfree = ++i;
    262 		}
    263 		ifp--;
    264 		ifp->if_nextfree = oldlast;
    265 	}
    266 
    267 	(void) VOP_BWRITE(bp); /* Ifile */
    268 	lfs_vunref(vp);
    269 
    270 	return 0;
    271 }
    272 
    273 /* Allocate a new inode. */
    274 /* ARGSUSED */
    275 /* VOP_BWRITE 2i times */
    276 int
    277 lfs_valloc(void *v)
    278 {
    279 	struct vop_valloc_args /* {
    280 				  struct vnode *a_pvp;
    281 				  int a_mode;
    282 				  struct ucred *a_cred;
    283 				  struct vnode **a_vpp;
    284 				  } */ *ap = v;
    285 	struct lfs *fs;
    286 	struct buf *bp, *cbp;
    287 	struct ifile *ifp;
    288 	ino_t new_ino;
    289 	int error;
    290 	int new_gen;
    291 	CLEANERINFO *cip;
    292 
    293 	fs = VTOI(ap->a_pvp)->i_lfs;
    294 	if (fs->lfs_ronly)
    295 		return EROFS;
    296 	*ap->a_vpp = NULL;
    297 
    298 	if (fs->lfs_version == 1) {
    299 		/*
    300 		 * Use lfs_seglock here, instead of fs->lfs_freelock, to
    301 		 * ensure that the free list is not changed in between
    302 		 * the time that the ifile blocks are written to disk
    303 		 * and the time that the superblock is written to disk.
    304 		 */
    305 		lfs_seglock(fs, SEGM_PROT);
    306 	} else {
    307 		lockmgr(&fs->lfs_freelock, LK_EXCLUSIVE, 0);
    308 	}
    309 
    310 	/* Get the head of the freelist. */
    311 	LFS_GET_HEADFREE(fs, cip, cbp, &new_ino);
    312 
    313 #ifdef DIAGNOSTIC
    314 	if(new_ino == LFS_UNUSED_INUM) {
    315 #ifdef DEBUG
    316 		lfs_dump_super(fs);
    317 #endif /* DEBUG */
    318 		panic("inode 0 allocated [1]");
    319 	}
    320 #endif /* DIAGNOSTIC */
    321 #ifdef ALLOCPRINT
    322 	printf("lfs_valloc: allocate inode %d\n", new_ino);
    323 #endif
    324 
    325 	/*
    326 	 * Remove the inode from the free list and write the new start
    327 	 * of the free list into the superblock.
    328 	 */
    329 	LFS_IENTRY(ifp, fs, new_ino, bp);
    330 	if (ifp->if_daddr != LFS_UNUSED_DADDR)
    331 		panic("lfs_valloc: inuse inode %d on the free list", new_ino);
    332 	LFS_PUT_HEADFREE(fs, cip, cbp, ifp->if_nextfree);
    333 
    334 	new_gen = ifp->if_version; /* version was updated by vfree */
    335 	brelse(bp);
    336 
    337 	/* Extend IFILE so that the next lfs_valloc will succeed. */
    338 	if (fs->lfs_free == LFS_UNUSED_INUM) {
    339 		if ((error = extend_ifile(fs, ap->a_cred)) != 0) {
    340 			LFS_PUT_HEADFREE(fs, cip, cbp, new_ino);
    341 			if (fs->lfs_version == 1)
    342 				lfs_segunlock(fs);
    343 			else
    344 				lockmgr(&fs->lfs_freelock, LK_RELEASE, 0);
    345 			return error;
    346 		}
    347 	}
    348 #ifdef DIAGNOSTIC
    349 	if(fs->lfs_free == LFS_UNUSED_INUM)
    350 		panic("inode 0 allocated [3]");
    351 #endif /* DIAGNOSTIC */
    352 
    353 	if (fs->lfs_version == 1)
    354 		lfs_segunlock(fs);
    355 	else
    356 		lockmgr(&fs->lfs_freelock, LK_RELEASE, 0);
    357 
    358 	return lfs_ialloc(fs, ap->a_pvp, new_ino, new_gen, ap->a_vpp);
    359 }
    360 
    361 static int
    362 lfs_ialloc(struct lfs *fs, struct vnode *pvp, ino_t new_ino, int new_gen,
    363 	   struct vnode **vpp)
    364 {
    365 	struct inode *ip;
    366 	struct vnode *vp;
    367 	IFILE *ifp;
    368 	struct buf *bp, *cbp;
    369 	int error;
    370 	CLEANERINFO *cip;
    371 
    372 	error = getnewvnode(VT_LFS, pvp->v_mount, lfs_vnodeop_p, &vp);
    373 	/* printf("lfs_ialloc: ino %d vp %p error %d\n", new_ino, vp, error);*/
    374 	if (error)
    375 		goto errout;
    376 
    377 	lockmgr(&ufs_hashlock, LK_EXCLUSIVE, 0);
    378 	/* Create an inode to associate with the vnode. */
    379 	lfs_vcreate(pvp->v_mount, new_ino, vp);
    380 
    381 	ip = VTOI(vp);
    382 	LFS_SET_UINO(ip, IN_CHANGE | IN_MODIFIED);
    383 	/* Zero out the direct and indirect block addresses. */
    384 	bzero(&ip->i_din, sizeof(ip->i_din));
    385 	ip->i_din.ffs_din.di_inumber = new_ino;
    386 
    387 	/* Set a new generation number for this inode. */
    388 	if (new_gen)
    389 		ip->i_ffs_gen = new_gen;
    390 
    391 	/* Insert into the inode hash table. */
    392 	ufs_ihashins(ip);
    393 	lockmgr(&ufs_hashlock, LK_RELEASE, 0);
    394 
    395 	ufs_vinit(vp->v_mount, lfs_specop_p, lfs_fifoop_p, &vp);
    396 	ip = VTOI(vp);
    397 	/* printf("lfs_ialloc[2]: ino %d vp %p\n", new_ino, vp);*/
    398 
    399 	*vpp = vp;
    400 #if 1
    401 	if(!(vp->v_flag & VDIROP)) {
    402 		(void)lfs_vref(vp);
    403 		++lfs_dirvcount;
    404 	}
    405 	vp->v_flag |= VDIROP;
    406 
    407 	if(!(ip->i_flag & IN_ADIROP))
    408 		++fs->lfs_nadirop;
    409 	ip->i_flag |= IN_ADIROP;
    410 #endif
    411 	VREF(ip->i_devvp);
    412 	/* Set superblock modified bit and increment file count. */
    413 	fs->lfs_fmod = 1;
    414 	++fs->lfs_nfiles;
    415 	return (0);
    416 
    417     errout:
    418 	/*
    419 	 * Put the new inum back on the free list.
    420 	 */
    421 	LFS_IENTRY(ifp, fs, new_ino, bp);
    422 	ifp->if_daddr = LFS_UNUSED_DADDR;
    423 	LFS_GET_HEADFREE(fs, cip, cbp, &(ifp->if_nextfree));
    424 	LFS_PUT_HEADFREE(fs, cip, cbp, new_ino);
    425 	(void) VOP_BWRITE(bp); /* Ifile */
    426 
    427 	*vpp = NULLVP;
    428 	return (error);
    429 }
    430 
    431 /* Create a new vnode/inode pair and initialize what fields we can. */
    432 void
    433 lfs_vcreate(struct mount *mp, ino_t ino, struct vnode *vp)
    434 {
    435 	struct inode *ip;
    436 	struct ufsmount *ump;
    437 #ifdef QUOTA
    438 	int i;
    439 #endif
    440 
    441 	/* Get a pointer to the private mount structure. */
    442 	ump = VFSTOUFS(mp);
    443 
    444 	/* Initialize the inode. */
    445 	ip = pool_get(&lfs_inode_pool, PR_WAITOK);
    446 	vp->v_data = ip;
    447 	ip->i_vnode = vp;
    448 	ip->i_devvp = ump->um_devvp;
    449 	ip->i_dev = ump->um_dev;
    450 	ip->i_number = ip->i_din.ffs_din.di_inumber = ino;
    451 	ip->i_lfs = ump->um_lfs;
    452 #ifdef QUOTA
    453 	for (i = 0; i < MAXQUOTAS; i++)
    454 		ip->i_dquot[i] = NODQUOT;
    455 #endif
    456 	ip->i_lockf = 0;
    457 	ip->i_diroff = 0;
    458 	ip->i_ffs_mode = 0;
    459 	ip->i_ffs_size = 0;
    460 	ip->i_ffs_blocks = 0;
    461 	ip->i_lfs_effnblks = 0;
    462 	ip->i_flag = 0;
    463 	/* Why was IN_MODIFIED ever set here? */
    464 	/* LFS_SET_UINO(ip, IN_CHANGE | IN_MODIFIED); */
    465 }
    466 
    467 /* Free an inode. */
    468 /* ARGUSED */
    469 /* VOP_BWRITE 2i times */
    470 int
    471 lfs_vfree(void *v)
    472 {
    473 	struct vop_vfree_args /* {
    474 				 struct vnode *a_pvp;
    475 				 ino_t a_ino;
    476 				 int a_mode;
    477 				 } */ *ap = v;
    478 	SEGUSE *sup;
    479 	CLEANERINFO *cip;
    480 	struct buf *cbp, *bp;
    481 	struct ifile *ifp;
    482 	struct inode *ip;
    483 	struct vnode *vp;
    484 	struct lfs *fs;
    485 	ufs_daddr_t old_iaddr;
    486 	ino_t ino, otail;
    487 	extern int lfs_dirvcount;
    488 
    489 	/* Get the inode number and file system. */
    490 	vp = ap->a_pvp;
    491 	ip = VTOI(vp);
    492 	fs = ip->i_lfs;
    493 	ino = ip->i_number;
    494 
    495 	/* Drain of pending writes */
    496 	if (fs->lfs_version > 1 && WRITEINPROG(vp))
    497 		tsleep(vp, (PRIBIO+1), "lfs_vfree", 0);
    498 
    499 	if (fs->lfs_version == 1)
    500 		lfs_seglock(fs, SEGM_PROT);
    501 	else
    502 		lockmgr(&fs->lfs_freelock, LK_EXCLUSIVE, 0);
    503 
    504 	if(vp->v_flag & VDIROP) {
    505 		--lfs_dirvcount;
    506 		vp->v_flag &= ~VDIROP;
    507 		wakeup(&lfs_dirvcount);
    508 		lfs_vunref(vp);
    509 	}
    510 	if (ip->i_flag & IN_ADIROP) {
    511 		--fs->lfs_nadirop;
    512 		ip->i_flag &= ~IN_ADIROP;
    513 	}
    514 
    515 	LFS_CLR_UINO(ip, IN_ACCESSED|IN_CLEANING|IN_MODIFIED);
    516 	ip->i_flag &= ~IN_ALLMOD;
    517 
    518 	/*
    519 	 * Set the ifile's inode entry to unused, increment its version number
    520 	 * and link it onto the free chain.
    521 	 */
    522 	LFS_IENTRY(ifp, fs, ino, bp);
    523 	old_iaddr = ifp->if_daddr;
    524 	ifp->if_daddr = LFS_UNUSED_DADDR;
    525 	++ifp->if_version;
    526 	if (fs->lfs_version == 1) {
    527 		LFS_GET_HEADFREE(fs, cip, cbp, &(ifp->if_nextfree));
    528 		LFS_PUT_HEADFREE(fs, cip, cbp, ino);
    529 		(void) VOP_BWRITE(bp); /* Ifile */
    530 	} else {
    531 		ifp->if_nextfree = LFS_UNUSED_INUM;
    532 		/*
    533 		 * XXX Writing the freed node here means that it might not
    534 		 * XXX make it into the free list in the event of a crash
    535 		 * XXX (the ifile could be written before the rest of this
    536 		 * XXX completes).
    537 		 */
    538 		(void) VOP_BWRITE(bp); /* Ifile */
    539 		LFS_GET_TAILFREE(fs, cip, cbp, &otail);
    540 		LFS_IENTRY(ifp, fs, otail, bp);
    541 		ifp->if_nextfree = ino;
    542 		VOP_BWRITE(bp);
    543 		LFS_PUT_TAILFREE(fs, cip, cbp, ino);
    544 	}
    545 #ifdef DIAGNOSTIC
    546 	if(ino == LFS_UNUSED_INUM) {
    547 		panic("inode 0 freed");
    548 	}
    549 #endif /* DIAGNOSTIC */
    550 	if (old_iaddr != LFS_UNUSED_DADDR) {
    551 		LFS_SEGENTRY(sup, fs, dtosn(fs, old_iaddr), bp);
    552 #ifdef DIAGNOSTIC
    553 		if (sup->su_nbytes < DINODE_SIZE) {
    554 			printf("lfs_vfree: negative byte count"
    555 			       " (segment %d short by %d)\n",
    556 			       dtosn(fs, old_iaddr),
    557 			       (int)DINODE_SIZE - sup->su_nbytes);
    558 			panic("lfs_vfree: negative byte count");
    559 			sup->su_nbytes = DINODE_SIZE;
    560 		}
    561 #endif
    562 		sup->su_nbytes -= DINODE_SIZE;
    563 		(void) VOP_BWRITE(bp); /* Ifile */
    564 	}
    565 
    566 	/* Set superblock modified bit and decrement file count. */
    567 	fs->lfs_fmod = 1;
    568 	--fs->lfs_nfiles;
    569 
    570 	if (fs->lfs_version == 1)
    571 		lfs_segunlock(fs);
    572 	else
    573 		lockmgr(&fs->lfs_freelock, LK_RELEASE, 0);
    574 	return (0);
    575 }
    576