xref: /freebsd-13-stable/sbin/fsck_ffs/inode.c (revision 6f87402a02f0801942fe8f0d9a8f7f3e04dfbb01)

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1986, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if 0
#ifndef lint
static const char sccsid[] = "@(#)inode.c	8.8 (Berkeley) 4/28/95";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/stdint.h>
#include <sys/sysctl.h>

#include <ufs/ufs/dinode.h>
#include <ufs/ufs/dir.h>
#include <ufs/ffs/fs.h>

#include <err.h>
#include <pwd.h>
#include <string.h>
#include <time.h>
#include <libufs.h>

#include "fsck.h"

struct bufarea *icachebp;	/* inode cache buffer */
static time_t now;		/* current time of day */

static int iblock(struct inodesc *, off_t isize, int type);
static ufs2_daddr_t indir_blkatoff(ufs2_daddr_t, ino_t, ufs_lbn_t, ufs_lbn_t,
    struct bufarea **);
static int snapclean(struct inodesc *idesc);
static void chkcopyonwrite(struct fs *, ufs2_daddr_t,
    ufs2_daddr_t (*checkblkavail)(ufs2_daddr_t, long));

int
ckinode(union dinode *dp, struct inodesc *idesc)
{
	off_t remsize, sizepb;
	int i, offset, ret;
	struct inode ip;
	union dinode dino;
	ufs2_daddr_t ndb;
	mode_t mode;
	char pathbuf[MAXPATHLEN + 1];

	if (idesc->id_fix != IGNORE)
		idesc->id_fix = DONTKNOW;
	idesc->id_dp = dp;
	idesc->id_lbn = -1;
	idesc->id_lballoc = -1;
	idesc->id_level = 0;
	idesc->id_entryno = 0;
	idesc->id_filesize = DIP(dp, di_size);
	mode = DIP(dp, di_mode) & IFMT;
	if (mode == IFBLK || mode == IFCHR || (mode == IFLNK &&
	    DIP(dp, di_size) < (unsigned)sblock.fs_maxsymlinklen))
		return (KEEPON);
	if (sblock.fs_magic == FS_UFS1_MAGIC)
		dino.dp1 = dp->dp1;
	else
		dino.dp2 = dp->dp2;
	if (DIP(&dino, di_size) < 0) {
		pfatal("NEGATIVE INODE SIZE %jd\n", DIP(&dino, di_size));
		return (STOP);
	}
	ndb = howmany(DIP(&dino, di_size), sblock.fs_bsize);
	for (i = 0; i < UFS_NDADDR; i++) {
		idesc->id_lbn++;
		if (--ndb == 0 &&
		    (offset = blkoff(&sblock, DIP(&dino, di_size))) != 0)
			idesc->id_numfrags =
				numfrags(&sblock, fragroundup(&sblock, offset));
		else
			idesc->id_numfrags = sblock.fs_frag;
		if (DIP(&dino, di_db[i]) == 0) {
			if (idesc->id_type == DATA && ndb >= 0) {
				/* An empty block in a directory XXX */
				getpathname(pathbuf, idesc->id_number,
						idesc->id_number);
				pfatal("DIRECTORY %s: CONTAINS EMPTY BLOCKS",
					pathbuf);
				if (reply("ADJUST LENGTH") == 1) {
					ginode(idesc->id_number, &ip);
					DIP_SET(ip.i_dp, di_size,
					    i * sblock.fs_bsize);
					printf(
					    "YOU MUST RERUN FSCK AFTERWARDS\n");
					rerun = 1;
					inodirty(&ip);
					irelse(&ip);
				}
				return (STOP);
			}
			continue;
		}
		idesc->id_blkno = DIP(&dino, di_db[i]);
		if (idesc->id_type != DATA)
			ret = (*idesc->id_func)(idesc);
		else
			ret = dirscan(idesc);
		if (ret & STOP)
			return (ret);
	}
	idesc->id_numfrags = sblock.fs_frag;
	remsize = DIP(&dino, di_size) - sblock.fs_bsize * UFS_NDADDR;
	sizepb = sblock.fs_bsize;
	for (i = 0; i < UFS_NIADDR; i++) {
		sizepb *= NINDIR(&sblock);
		idesc->id_level = i + 1;
		if (DIP(&dino, di_ib[i])) {
			idesc->id_blkno = DIP(&dino, di_ib[i]);
			ret = iblock(idesc, remsize, BT_LEVEL1 + i);
			if (ret & STOP)
				return (ret);
		} else if (remsize > 0) {
			idesc->id_lbn += sizepb / sblock.fs_bsize;
			if (idesc->id_type == DATA) {
				/* An empty block in a directory XXX */
				getpathname(pathbuf, idesc->id_number,
						idesc->id_number);
				pfatal("DIRECTORY %s: CONTAINS EMPTY BLOCKS",
					pathbuf);
				if (reply("ADJUST LENGTH") == 1) {
					ginode(idesc->id_number, &ip);
					DIP_SET(ip.i_dp, di_size,
					    DIP(ip.i_dp, di_size) - remsize);
					remsize = 0;
					printf(
					    "YOU MUST RERUN FSCK AFTERWARDS\n");
					rerun = 1;
					inodirty(&ip);
					irelse(&ip);
					break;
				}
			}
		}
		remsize -= sizepb;
	}
	return (KEEPON);
}

static int
iblock(struct inodesc *idesc, off_t isize, int type)
{
	struct inode ip;
	struct bufarea *bp;
	int i, n, (*func)(struct inodesc *), nif;
	off_t sizepb;
	char buf[BUFSIZ];
	char pathbuf[MAXPATHLEN + 1];

	if (idesc->id_type != DATA) {
		func = idesc->id_func;
		if (((n = (*func)(idesc)) & KEEPON) == 0)
			return (n);
	} else
		func = dirscan;
	bp = getdatablk(idesc->id_blkno, sblock.fs_bsize, type);
	if (bp->b_errs != 0) {
		brelse(bp);
		return (SKIP);
	}
	idesc->id_bp = bp;
	idesc->id_level--;
	for (sizepb = sblock.fs_bsize, i = 0; i < idesc->id_level; i++)
		sizepb *= NINDIR(&sblock);
	if (howmany(isize, sizepb) > NINDIR(&sblock))
		nif = NINDIR(&sblock);
	else
		nif = howmany(isize, sizepb);
	if (idesc->id_func == pass1check && nif < NINDIR(&sblock)) {
		for (i = nif; i < NINDIR(&sblock); i++) {
			if (IBLK(bp, i) == 0)
				continue;
			(void)sprintf(buf, "PARTIALLY TRUNCATED INODE I=%lu",
			    (u_long)idesc->id_number);
			if (preen) {
				pfatal("%s", buf);
			} else if (dofix(idesc, buf)) {
				IBLK_SET(bp, i, 0);
				dirty(bp);
			}
		}
		flush(fswritefd, bp);
	}
	for (i = 0; i < nif; i++) {
		if (IBLK(bp, i)) {
			idesc->id_blkno = IBLK(bp, i);
			bp->b_index = i;
			if (idesc->id_level == 0) {
				idesc->id_lbn++;
				n = (*func)(idesc);
			} else {
				n = iblock(idesc, isize, type - 1);
				idesc->id_level++;
			}
			if (n & STOP) {
				brelse(bp);
				return (n);
			}
		} else {
			idesc->id_lbn += sizepb / sblock.fs_bsize;
			if (idesc->id_type == DATA && isize > 0) {
				/* An empty block in a directory XXX */
				getpathname(pathbuf, idesc->id_number,
						idesc->id_number);
				pfatal("DIRECTORY %s: CONTAINS EMPTY BLOCKS",
					pathbuf);
				if (reply("ADJUST LENGTH") == 1) {
					ginode(idesc->id_number, &ip);
					DIP_SET(ip.i_dp, di_size,
					    DIP(ip.i_dp, di_size) - isize);
					isize = 0;
					printf(
					    "YOU MUST RERUN FSCK AFTERWARDS\n");
					rerun = 1;
					inodirty(&ip);
					brelse(bp);
					return(STOP);
				}
			}
		}
		isize -= sizepb;
	}
	brelse(bp);
	return (KEEPON);
}

/*
 * Finds the disk block address at the specified lbn within the inode
 * specified by dp.  This follows the whole tree and honors di_size and
 * di_extsize so it is a true test of reachability.  The lbn may be
 * negative if an extattr or indirect block is requested.
 */
ufs2_daddr_t
ino_blkatoff(union dinode *dp, ino_t ino, ufs_lbn_t lbn, int *frags,
    struct bufarea **bpp)
{
	ufs_lbn_t tmpval;
	ufs_lbn_t cur;
	ufs_lbn_t next;
	int i;

	*frags = 0;
	if (bpp != NULL)
		*bpp = NULL;
	/*
	 * Handle extattr blocks first.
	 */
	if (lbn < 0 && lbn >= -UFS_NXADDR) {
		lbn = -1 - lbn;
		if (lbn > lblkno(&sblock, dp->dp2.di_extsize - 1))
			return (0);
		*frags = numfrags(&sblock,
		    sblksize(&sblock, dp->dp2.di_extsize, lbn));
		return (dp->dp2.di_extb[lbn]);
	}
	/*
	 * Now direct and indirect.
	 */
	if (DIP(dp, di_mode) == IFLNK &&
	    DIP(dp, di_size) < sblock.fs_maxsymlinklen)
		return (0);
	if (lbn >= 0 && lbn < UFS_NDADDR) {
		*frags = numfrags(&sblock,
		    sblksize(&sblock, DIP(dp, di_size), lbn));
		return (DIP(dp, di_db[lbn]));
	}
	*frags = sblock.fs_frag;

	for (i = 0, tmpval = NINDIR(&sblock), cur = UFS_NDADDR; i < UFS_NIADDR;
	    i++, tmpval *= NINDIR(&sblock), cur = next) {
		next = cur + tmpval;
		if (lbn == -cur - i)
			return (DIP(dp, di_ib[i]));
		/*
		 * Determine whether the lbn in question is within this tree.
		 */
		if (lbn < 0 && -lbn >= next)
			continue;
		if (lbn > 0 && lbn >= next)
			continue;
		if (DIP(dp, di_ib[i]) == 0)
			return (0);
		return (indir_blkatoff(DIP(dp, di_ib[i]), ino, -cur - i, lbn,
		    bpp));
	}
	pfatal("lbn %jd not in ino %ju\n", lbn, (uintmax_t)ino);
	return (0);
}

/*
 * Fetch an indirect block to find the block at a given lbn.  The lbn
 * may be negative to fetch a specific indirect block pointer or positive
 * to fetch a specific block.
 */
static ufs2_daddr_t
indir_blkatoff(ufs2_daddr_t blk, ino_t ino, ufs_lbn_t cur, ufs_lbn_t lbn,
    struct bufarea **bpp)
{
	struct bufarea *bp;
	ufs_lbn_t lbnadd;
	ufs_lbn_t base;
	int i, level;

	level = lbn_level(cur);
	if (level == -1)
		pfatal("Invalid indir lbn %jd in ino %ju\n",
		    lbn, (uintmax_t)ino);
	if (level == 0 && lbn < 0)
		pfatal("Invalid lbn %jd in ino %ju\n",
		    lbn, (uintmax_t)ino);
	lbnadd = 1;
	base = -(cur + level);
	for (i = level; i > 0; i--)
		lbnadd *= NINDIR(&sblock);
	if (lbn > 0)
		i = (lbn - base) / lbnadd;
	else
		i = (-lbn - base) / lbnadd;
	if (i < 0 || i >= NINDIR(&sblock)) {
		pfatal("Invalid indirect index %d produced by lbn %jd "
		    "in ino %ju\n", i, lbn, (uintmax_t)ino);
		return (0);
	}
	if (level == 0)
		cur = base + (i * lbnadd);
	else
		cur = -(base + (i * lbnadd)) - (level - 1);
	bp = getdatablk(blk, sblock.fs_bsize, BT_LEVEL1 + level);
	if (bp->b_errs != 0)
		return (0);
	blk = IBLK(bp, i);
	bp->b_index = i;
	if (cur == lbn || blk == 0) {
		if (bpp != NULL)
			*bpp = bp;
		else
			brelse(bp);
		return (blk);
	}
	brelse(bp);
	if (level == 0)
		pfatal("Invalid lbn %jd at level 0 for ino %ju\n", lbn,
		    (uintmax_t)ino);
	return (indir_blkatoff(blk, ino, cur, lbn, bpp));
}

/*
 * Check that a block in a legal block number.
 * Return 0 if in range, 1 if out of range.
 */
int
chkrange(ufs2_daddr_t blk, int cnt)
{
	int c;

	if (cnt <= 0 || blk <= 0 || blk >= maxfsblock ||
	    cnt > maxfsblock - blk) {
		if (debug)
			printf("out of range: blk %ld, offset %i, size %d\n",
			    (long)blk, (int)fragnum(&sblock, blk), cnt);
		return (1);
	}
	if (cnt > sblock.fs_frag ||
	    fragnum(&sblock, blk) + cnt > sblock.fs_frag) {
		if (debug)
			printf("bad size: blk %ld, offset %i, size %d\n",
			    (long)blk, (int)fragnum(&sblock, blk), cnt);
		return (1);
	}
	c = dtog(&sblock, blk);
	if (blk < cgdmin(&sblock, c)) {
		if ((blk + cnt) > cgsblock(&sblock, c)) {
			if (debug) {
				printf("blk %ld < cgdmin %ld;",
				    (long)blk, (long)cgdmin(&sblock, c));
				printf(" blk + cnt %ld > cgsbase %ld\n",
				    (long)(blk + cnt),
				    (long)cgsblock(&sblock, c));
			}
			return (1);
		}
	} else {
		if ((blk + cnt) > cgbase(&sblock, c+1)) {
			if (debug)  {
				printf("blk %ld >= cgdmin %ld;",
				    (long)blk, (long)cgdmin(&sblock, c));
				printf(" blk + cnt %ld > sblock.fs_fpg %ld\n",
				    (long)(blk + cnt), (long)sblock.fs_fpg);
			}
			return (1);
		}
	}
	return (0);
}

/*
 * General purpose interface for reading inodes.
 *
 * firstinum and lastinum track contents of getnextino() cache (below).
 */
static ino_t firstinum, lastinum;
static struct bufarea inobuf;

void
ginode(ino_t inumber, struct inode *ip)
{
	ufs2_daddr_t iblk;
	union dinodep dpp;
	struct ufs2_dinode *dp;

	if (inumber < UFS_ROOTINO || inumber >= maxino)
		errx(EEXIT, "bad inode number %ju to ginode",
		    (uintmax_t)inumber);
	ip->i_number = inumber;
	if (inumber >= firstinum && inumber < lastinum) {
		/* contents in getnextino() cache */
		ip->i_bp = &inobuf;
		inobuf.b_refcnt++;
		inobuf.b_index = firstinum;
	} else if (icachebp != NULL &&
	    inumber >= icachebp->b_index &&
	    inumber < icachebp->b_index + INOPB(&sblock)) {
		/* take an additional reference for the returned inode */
		icachebp->b_refcnt++;
		ip->i_bp = icachebp;
	} else {
		iblk = ino_to_fsba(&sblock, inumber);
		/* release our cache-hold reference on old icachebp */
		if (icachebp != NULL)
			brelse(icachebp);
		icachebp = getdatablk(iblk, sblock.fs_bsize, BT_INODES);
		if (icachebp->b_errs != 0) {
			icachebp = NULL;
			ip->i_bp = NULL;
			ip->i_dp = &zino;
			return;
		}
		/* take a cache-hold reference on new icachebp */
		icachebp->b_refcnt++;
		icachebp->b_index = rounddown(inumber, INOPB(&sblock));
		ip->i_bp = icachebp;
	}
	if (sblock.fs_magic == FS_UFS1_MAGIC) {
		ip->i_dp = (union dinode *)
		    &ip->i_bp->b_un.b_dinode1[inumber - ip->i_bp->b_index];
		dpp.dp1 = (struct ufs1_dinode *)ip->i_dp;
		if (ffs_oldfscompat_inode_read(&sblock, dpp, now))
			inodirty(ip);
		return;
	}
	ip->i_dp = (union dinode *)
	    &ip->i_bp->b_un.b_dinode2[inumber - ip->i_bp->b_index];
	dpp.dp2 = dp = (struct ufs2_dinode *)ip->i_dp;
	/* Do not check hash of inodes being created */
	if (dp->di_mode != 0 && ffs_verify_dinode_ckhash(&sblock, dp)) {
		pwarn("INODE CHECK-HASH FAILED");
		prtinode(ip);
		if (preen || reply("FIX") != 0) {
			if (preen)
				printf(" (FIXED)\n");
			ffs_update_dinode_ckhash(&sblock, dp);
			inodirty(ip);
		}
	}
	if (ffs_oldfscompat_inode_read(&sblock, dpp, now))
		inodirty(ip);
}

/*
 * Release a held inode.
 */
void
irelse(struct inode *ip)
{

	/* Check for failed inode read */
	if (ip->i_bp == NULL)
		return;
	if (debug && sblock.fs_magic == FS_UFS2_MAGIC &&
	    ffs_verify_dinode_ckhash(&sblock, (struct ufs2_dinode *)ip->i_dp)) {
		pwarn("irelse: releasing inode with bad check-hash");
		prtinode(ip);
	}
	if (ip->i_bp->b_refcnt <= 0)
		pfatal("irelse: releasing unreferenced ino %ju\n",
		    (uintmax_t) ip->i_number);
	brelse(ip->i_bp);
}

/*
 * Special purpose version of ginode used to optimize first pass
 * over all the inodes in numerical order.
 */
static ino_t nextinum, lastvalidinum;
static long readcount, readpercg, fullcnt, inobufsize, partialcnt, partialsize;

union dinode *
getnextinode(ino_t inumber, int rebuiltcg)
{
	int j;
	long size;
	mode_t mode;
	ufs2_daddr_t ndb, blk;
	union dinode *dp;
	union dinodep dpp;
	struct inode ip;
	static caddr_t nextinop;

	if (inumber != nextinum++ || inumber > lastvalidinum)
		errx(EEXIT, "bad inode number %ju to nextinode",
		    (uintmax_t)inumber);
	if (inumber >= lastinum) {
		readcount++;
		firstinum = lastinum;
		blk = ino_to_fsba(&sblock, lastinum);
		if (readcount % readpercg == 0) {
			size = partialsize;
			lastinum += partialcnt;
		} else {
			size = inobufsize;
			lastinum += fullcnt;
		}
		/*
		 * Flush old contents in case they have been updated.
		 * If getblk encounters an error, it will already have zeroed
		 * out the buffer, so we do not need to do so here.
		 */
		if (inobuf.b_refcnt != 0)
			pfatal("Non-zero getnextinode() ref count %d\n",
			    inobuf.b_refcnt);
		flush(fswritefd, &inobuf);
		getblk(&inobuf, blk, size);
		nextinop = inobuf.b_un.b_buf;
	}
	dp = (union dinode *)nextinop;
	if (sblock.fs_magic == FS_UFS1_MAGIC) {
		nextinop += sizeof(struct ufs1_dinode);
		dpp.dp1 = (struct ufs1_dinode *)dp;
	} else {
		nextinop += sizeof(struct ufs2_dinode);
		dpp.dp2 = (struct ufs2_dinode *)dp;
	}
	if ((ckhashadd & CK_INODE) != 0) {
		ffs_update_dinode_ckhash(&sblock, (struct ufs2_dinode *)dp);
		dirty(&inobuf);
	}
	if (ffs_verify_dinode_ckhash(&sblock, (struct ufs2_dinode *)dp) != 0) {
		pwarn("INODE CHECK-HASH FAILED");
		ip.i_bp = NULL;
		ip.i_dp = dp;
		ip.i_number = inumber;
		prtinode(&ip);
		if (preen || reply("FIX") != 0) {
			if (preen)
				printf(" (FIXED)\n");
			ffs_update_dinode_ckhash(&sblock,
			    (struct ufs2_dinode *)dp);
			dirty(&inobuf);
		}
	}
	if (ffs_oldfscompat_inode_read(&sblock, dpp, now))
		dirty(&inobuf);
	if (rebuiltcg && (char *)dp == inobuf.b_un.b_buf) {
		/*
		 * Try to determine if we have reached the end of the
		 * allocated inodes.
		 */
		mode = DIP(dp, di_mode) & IFMT;
		if (mode == 0) {
			if (memcmp(dp->dp2.di_db, zino.dp2.di_db,
				UFS_NDADDR * sizeof(ufs2_daddr_t)) ||
			      memcmp(dp->dp2.di_ib, zino.dp2.di_ib,
				UFS_NIADDR * sizeof(ufs2_daddr_t)) ||
			      dp->dp2.di_mode || dp->dp2.di_size)
				return (NULL);
			return (dp);
		}
		if (!ftypeok(dp))
			return (NULL);
		ndb = howmany(DIP(dp, di_size), sblock.fs_bsize);
		if (ndb < 0)
			return (NULL);
		if (mode == IFBLK || mode == IFCHR)
			ndb++;
		if (mode == IFLNK) {
			/*
			 * Fake ndb value so direct/indirect block checks below
			 * will detect any garbage after symlink string.
			 */
			if (DIP(dp, di_size) < (off_t)sblock.fs_maxsymlinklen) {
				ndb = howmany(DIP(dp, di_size),
				    sizeof(ufs2_daddr_t));
				if (ndb > UFS_NDADDR) {
					j = ndb - UFS_NDADDR;
					for (ndb = 1; j > 1; j--)
						ndb *= NINDIR(&sblock);
					ndb += UFS_NDADDR;
				}
			}
		}
		for (j = ndb; ndb < UFS_NDADDR && j < UFS_NDADDR; j++)
			if (DIP(dp, di_db[j]) != 0)
				return (NULL);
		for (j = 0, ndb -= UFS_NDADDR; ndb > 0; j++)
			ndb /= NINDIR(&sblock);
		for (; j < UFS_NIADDR; j++)
			if (DIP(dp, di_ib[j]) != 0)
				return (NULL);
	}
	return (dp);
}

void
setinodebuf(int cg, ino_t inosused)
{
	struct timespec time;
	ino_t inum;

	/*
	 * Get the current value of the present time.
	 * This will happen before each cylinder group is scanned.
	 * If for some reason getting the time fails, we will use
	 * the last time that the superblock was updated.
	 */
	if (clock_gettime(CLOCK_REALTIME_FAST, &time) == 0)
		now = time.tv_sec;
	else
		now = sblock.fs_time;
	inum = cg * sblock.fs_ipg;
	lastvalidinum = inum + inosused - 1;
	nextinum = inum;
	lastinum = inum;
	readcount = 0;
	/* Flush old contents in case they have been updated */
	flush(fswritefd, &inobuf);
	inobuf.b_bno = 0;
	if (inobuf.b_un.b_buf == NULL) {
		inobufsize = blkroundup(&sblock,
		    MAX(INOBUFSIZE, sblock.fs_bsize));
		initbarea(&inobuf, BT_INODES);
		if ((inobuf.b_un.b_buf = Malloc((unsigned)inobufsize)) == NULL)
			errx(EEXIT, "cannot allocate space for inode buffer");
	}
	fullcnt = inobufsize / ((sblock.fs_magic == FS_UFS1_MAGIC) ?
	    sizeof(struct ufs1_dinode) : sizeof(struct ufs2_dinode));
	readpercg = inosused / fullcnt;
	partialcnt = inosused % fullcnt;
	partialsize = fragroundup(&sblock,
	    partialcnt * ((sblock.fs_magic == FS_UFS1_MAGIC) ?
	    sizeof(struct ufs1_dinode) : sizeof(struct ufs2_dinode)));
	if (partialcnt != 0) {
		readpercg++;
	} else {
		partialcnt = fullcnt;
		partialsize = inobufsize;
	}
}

int
freeblock(struct inodesc *idesc)
{
	struct dups *dlp;
	struct bufarea *cgbp;
	struct cg *cgp;
	ufs2_daddr_t blkno;
	long size, nfrags;

	blkno = idesc->id_blkno;
	if (idesc->id_type == SNAP) {
		pfatal("clearing a snapshot dinode\n");
		return (STOP);
	}
	size = lfragtosize(&sblock, idesc->id_numfrags);
	if (snapblkfree(&sblock, blkno, size, idesc->id_number,
	    std_checkblkavail))
		return (KEEPON);
	for (nfrags = idesc->id_numfrags; nfrags > 0; blkno++, nfrags--) {
		if (chkrange(blkno, 1)) {
			return (SKIP);
		} else if (testbmap(blkno)) {
			for (dlp = duplist; dlp; dlp = dlp->next) {
				if (dlp->dup != blkno)
					continue;
				dlp->dup = duplist->dup;
				dlp = duplist;
				duplist = duplist->next;
				free((char *)dlp);
				break;
			}
			if (dlp == NULL) {
				clrbmap(blkno);
				n_blks--;
			}
		}
	}
	/*
	 * If all successfully returned, account for them.
	 */
	if (nfrags == 0) {
		cgbp = cglookup(dtog(&sblock, idesc->id_blkno));
		cgp = cgbp->b_un.b_cg;
		if (idesc->id_numfrags == sblock.fs_frag)
			cgp->cg_cs.cs_nbfree++;
		else
			cgp->cg_cs.cs_nffree += idesc->id_numfrags;
		cgdirty(cgbp);
	}
	return (KEEPON);
}

/*
 * Prepare a snapshot file for being removed.
 */
void
snapremove(ino_t inum)
{
	struct inodesc idesc;
	struct inode ip;
	int i;

	for (i = 0; i < snapcnt; i++)
		if (snaplist[i].i_number == inum)
			break;
	if (i == snapcnt)
		ginode(inum, &ip);
	else
		ip = snaplist[i];
	if ((DIP(ip.i_dp, di_flags) & SF_SNAPSHOT) == 0) {
		printf("snapremove: inode %jd is not a snapshot\n",
		    (intmax_t)inum);
		if (i == snapcnt)
			irelse(&ip);
		return;
	}
	if (debug)
		printf("snapremove: remove %sactive snapshot %jd\n",
		    i == snapcnt ? "in" : "", (intmax_t)inum);
	/*
	 * If on active snapshot list, remove it.
	 */
	if (i < snapcnt) {
		for (i++; i < FSMAXSNAP; i++) {
			if (sblock.fs_snapinum[i] == 0)
				break;
			snaplist[i - 1] = snaplist[i];
			sblock.fs_snapinum[i - 1] = sblock.fs_snapinum[i];
		}
		sblock.fs_snapinum[i - 1] = 0;
		bzero(&snaplist[i - 1], sizeof(struct inode));
		snapcnt--;
	}
	memset(&idesc, 0, sizeof(struct inodesc));
	idesc.id_type = SNAP;
	idesc.id_func = snapclean;
	idesc.id_number = inum;
	(void)ckinode(ip.i_dp, &idesc);
	DIP_SET(ip.i_dp, di_flags, DIP(ip.i_dp, di_flags) & ~SF_SNAPSHOT);
	inodirty(&ip);
	irelse(&ip);
}

static int
snapclean(struct inodesc *idesc)
{
	ufs2_daddr_t blkno;
	struct bufarea *bp;
	union dinode *dp;

	blkno = idesc->id_blkno;
	if (blkno == 0)
		return (KEEPON);

	dp = idesc->id_dp;
	if (blkno == BLK_NOCOPY || blkno == BLK_SNAP) {
		if (idesc->id_lbn < UFS_NDADDR) {
			DIP_SET(dp, di_db[idesc->id_lbn], 0);
		} else {
			bp = idesc->id_bp;
			IBLK_SET(bp, bp->b_index, 0);
			dirty(bp);
		}
	}
	return (KEEPON);
}

/*
 * Notification that a block is being freed. Return zero if the free
 * should be allowed to proceed. Return non-zero if the snapshot file
 * wants to claim the block. The block will be claimed if it is an
 * uncopied part of one of the snapshots. It will be freed if it is
 * either a BLK_NOCOPY or has already been copied in all of the snapshots.
 * If a fragment is being freed, then all snapshots that care about
 * it must make a copy since a snapshot file can only claim full sized
 * blocks. Note that if more than one snapshot file maps the block,
 * we can pick one at random to claim it. Since none of the snapshots
 * can change, we are assurred that they will all see the same unmodified
 * image. When deleting a snapshot file (see ino_trunc above), we
 * must push any of these claimed blocks to one of the other snapshots
 * that maps it. These claimed blocks are easily identified as they will
 * have a block number equal to their logical block number within the
 * snapshot. A copied block can never have this property because they
 * must always have been allocated from a BLK_NOCOPY location.
 */
int
snapblkfree(struct fs *fs, ufs2_daddr_t bno, long size, ino_t inum,
	ufs2_daddr_t (*checkblkavail)(ufs2_daddr_t blkno, long frags))
{
	union dinode *dp;
	struct inode ip;
	struct bufarea *snapbp;
	ufs_lbn_t lbn;
	ufs2_daddr_t blkno, relblkno;
	int i, frags, claimedblk, copydone;

	/* If no snapshots, nothing to do */
	if (snapcnt == 0)
		return (0);
	if (debug)
		printf("snapblkfree: in ino %jd free blkno %jd, size %jd\n",
		    (intmax_t)inum, (intmax_t)bno, (intmax_t)size);
	relblkno = blknum(fs, bno);
	lbn = fragstoblks(fs, relblkno);
	/* Direct blocks are always pre-copied */
	if (lbn < UFS_NDADDR)
		return (0);
	copydone = 0;
	claimedblk = 0;
	for (i = 0; i < snapcnt; i++) {
		/*
		 * Lookup block being freed.
		 */
		ip = snaplist[i];
		dp = ip.i_dp;
		blkno = ino_blkatoff(dp, inum != 0 ? inum : ip.i_number,
		    lbn, &frags, &snapbp);
		/*
		 * Check to see if block needs to be copied.
		 */
		if (blkno == 0) {
			/*
			 * A block that we map is being freed. If it has not
			 * been claimed yet, we will claim or copy it (below).
			 */
			claimedblk = 1;
		} else if (blkno == BLK_SNAP) {
			/*
			 * No previous snapshot claimed the block,
			 * so it will be freed and become a BLK_NOCOPY
			 * (don't care) for us.
			 */
			if (claimedblk)
				pfatal("snapblkfree: inconsistent block type");
			IBLK_SET(snapbp, snapbp->b_index, BLK_NOCOPY);
			dirty(snapbp);
			brelse(snapbp);
			continue;
		} else /* BLK_NOCOPY or default */ {
			/*
			 * If the snapshot has already copied the block
			 * (default), or does not care about the block,
			 * it is not needed.
			 */
			brelse(snapbp);
			continue;
		}
		/*
		 * If this is a full size block, we will just grab it
		 * and assign it to the snapshot inode. Otherwise we
		 * will proceed to copy it. See explanation for this
		 * routine as to why only a single snapshot needs to
		 * claim this block.
		 */
		if (size == fs->fs_bsize) {
			if (debug)
				printf("Grabonremove snapshot %ju lbn %jd "
				    "from inum %ju\n", (intmax_t)ip.i_number,
				    (intmax_t)lbn, (uintmax_t)inum);
			IBLK_SET(snapbp, snapbp->b_index, relblkno);
			dirty(snapbp);
			brelse(snapbp);
			DIP_SET(dp, di_blocks,
			    DIP(dp, di_blocks) + btodb(size));
			inodirty(&ip);
			return (1);
		}

		/* First time through, read the contents of the old block. */
		if (copydone == 0) {
			copydone = 1;
			if (blread(fsreadfd, copybuf, fsbtodb(fs, relblkno),
			    fs->fs_bsize) != 0) {
				pfatal("Could not read snapshot %ju block "
				    "%jd\n", (intmax_t)ip.i_number,
				    (intmax_t)relblkno);
				continue;
			}
		}
		/*
		 * This allocation will never require any additional
		 * allocations for the snapshot inode.
		 */
		blkno = allocblk(dtog(fs, relblkno), fs->fs_frag,
		    checkblkavail);
		if (blkno == 0) {
			pfatal("Could not allocate block for snapshot %ju\n",
			    (intmax_t)ip.i_number);
			continue;
		}
		if (debug)
			printf("Copyonremove: snapino %jd lbn %jd for inum %ju "
			    "size %ld new blkno %jd\n", (intmax_t)ip.i_number,
			    (intmax_t)lbn, (uintmax_t)inum, size,
			    (intmax_t)blkno);
		blwrite(fswritefd, copybuf, fsbtodb(fs, blkno), fs->fs_bsize);
		IBLK_SET(snapbp, snapbp->b_index, blkno);
		dirty(snapbp);
		brelse(snapbp);
		DIP_SET(dp, di_blocks,
		    DIP(dp, di_blocks) + btodb(fs->fs_bsize));
		inodirty(&ip);
	}
	return (0);
}

/*
 * Notification that a block is being written. Return if the block
 * is part of a snapshot as snapshots never track other snapshots.
 * The block will be copied in all of the snapshots that are tracking
 * it and have not yet copied it. Some buffers may hold more than one
 * block. Here we need to check each block in the buffer.
 */
void
copyonwrite(struct fs *fs, struct bufarea *bp,
	ufs2_daddr_t (*checkblkavail)(ufs2_daddr_t blkno, long frags))
{
	ufs2_daddr_t copyblkno;
	long i, numblks;

	/* If no snapshots, nothing to do. */
	if (snapcnt == 0)
		return;
	numblks = blkroundup(fs, bp->b_size) / fs->fs_bsize;
	if (debug)
		prtbuf(bp, "copyonwrite: checking %jd block%s in buffer",
		    (intmax_t)numblks, numblks > 1 ? "s" : "");
	copyblkno = blknum(fs, dbtofsb(fs, bp->b_bno));
	for (i = 0; i < numblks; i++) {
		chkcopyonwrite(fs, copyblkno, checkblkavail);
		copyblkno += fs->fs_frag;
	}
}

static void
chkcopyonwrite(struct fs *fs, ufs2_daddr_t copyblkno,
	ufs2_daddr_t (*checkblkavail)(ufs2_daddr_t blkno, long frags))
{
	struct inode ip;
	union dinode *dp;
	struct bufarea *snapbp;
	ufs2_daddr_t blkno;
	int i, frags, copydone;
	ufs_lbn_t lbn;

	lbn = fragstoblks(fs, copyblkno);
	/* Direct blocks are always pre-copied */
	if (lbn < UFS_NDADDR)
		return;
	copydone = 0;
	for (i = 0; i < snapcnt; i++) {
		/*
		 * Lookup block being freed.
		 */
		ip = snaplist[i];
		dp = ip.i_dp;
		blkno = ino_blkatoff(dp, ip.i_number, lbn, &frags, &snapbp);
		/*
		 * Check to see if block needs to be copied.
		 */
		if (blkno != 0) {
			/*
			 * A block that we have already copied or don't track.
			 */
			brelse(snapbp);
			continue;
		}
		/* First time through, read the contents of the old block. */
		if (copydone == 0) {
			copydone = 1;
			if (blread(fsreadfd, copybuf, fsbtodb(fs, copyblkno),
			    fs->fs_bsize) != 0) {
				pfatal("Could not read snapshot %ju block "
				    "%jd\n", (intmax_t)ip.i_number,
				    (intmax_t)copyblkno);
				continue;
			}
		}
		/*
		 * This allocation will never require any additional
		 * allocations for the snapshot inode.
		 */
		if ((blkno = allocblk(dtog(fs, copyblkno), fs->fs_frag,
		    checkblkavail)) == 0) {
			pfatal("Could not allocate block for snapshot %ju\n",
			    (intmax_t)ip.i_number);
			continue;
		}
		if (debug)
			prtbuf(snapbp, "Copyonwrite: snapino %jd lbn %jd using "
			    "blkno %ju setting in buffer",
			    (intmax_t)ip.i_number, (intmax_t)lbn,
			    (intmax_t)blkno);
		blwrite(fswritefd, copybuf, fsbtodb(fs, blkno), fs->fs_bsize);
		IBLK_SET(snapbp, snapbp->b_index, blkno);
		dirty(snapbp);
		brelse(snapbp);
		DIP_SET(dp, di_blocks,
		    DIP(dp, di_blocks) + btodb(fs->fs_bsize));
		inodirty(&ip);
	}
	return;
}

/*
 * Traverse an inode and check that its block count is correct
 * fixing it if necessary.
 */
void
check_blkcnt(struct inode *ip)
{
	struct inodesc idesc;
	union dinode *dp;
	ufs2_daddr_t ndb;
	int j, ret, offset;

	dp = ip->i_dp;
	memset(&idesc, 0, sizeof(struct inodesc));
	idesc.id_func = pass1check;
	idesc.id_number = ip->i_number;
	idesc.id_type = (DIP(dp, di_flags) & SF_SNAPSHOT) == 0 ? ADDR : SNAP;
	(void)ckinode(dp, &idesc);
	if (sblock.fs_magic == FS_UFS2_MAGIC && dp->dp2.di_extsize > 0) {
		ndb = howmany(dp->dp2.di_extsize, sblock.fs_bsize);
		for (j = 0; j < UFS_NXADDR; j++) {
			if (--ndb == 0 &&
			    (offset = blkoff(&sblock, dp->dp2.di_extsize)) != 0)
				idesc.id_numfrags = numfrags(&sblock,
				    fragroundup(&sblock, offset));
			else
				idesc.id_numfrags = sblock.fs_frag;
			if (dp->dp2.di_extb[j] == 0)
				continue;
			idesc.id_blkno = dp->dp2.di_extb[j];
			ret = (*idesc.id_func)(&idesc);
			if (ret & STOP)
				break;
		}
	}
	idesc.id_entryno *= btodb(sblock.fs_fsize);
	if (DIP(dp, di_blocks) != idesc.id_entryno) {
		if (!(sujrecovery && preen)) {
			pwarn("INCORRECT BLOCK COUNT I=%lu (%ju should be %ju)",
			    (u_long)idesc.id_number,
			    (uintmax_t)DIP(dp, di_blocks),
			    (uintmax_t)idesc.id_entryno);
			if (preen)
				printf(" (CORRECTED)\n");
			else if (reply("CORRECT") == 0)
				return;
		}
		if (bkgrdflag == 0) {
			DIP_SET(dp, di_blocks, idesc.id_entryno);
			inodirty(ip);
		} else {
			cmd.value = idesc.id_number;
			cmd.size = idesc.id_entryno - DIP(dp, di_blocks);
			if (debug)
				printf("adjblkcnt ino %ju amount %lld\n",
				    (uintmax_t)cmd.value, (long long)cmd.size);
			if (sysctl(adjblkcnt, MIBSIZE, 0, 0,
			    &cmd, sizeof cmd) == -1)
				rwerror("ADJUST INODE BLOCK COUNT", cmd.value);
		}
	}
}

void
freeinodebuf(void)
{
	struct bufarea *bp;
	int i;

	/*
	 * Flush old contents in case they have been updated.
	 */
	flush(fswritefd, &inobuf);
	if (inobuf.b_un.b_buf != NULL)
		free((char *)inobuf.b_un.b_buf);
	inobuf.b_un.b_buf = NULL;
	firstinum = lastinum = 0;
	/*
	 * Reload the snapshot inodes in case any of them changed.
	 */
	for (i = 0; i < snapcnt; i++) {
		bp = snaplist[i].i_bp;
		bp->b_errs = blread(fsreadfd, bp->b_un.b_buf, bp->b_bno,
		    bp->b_size);
	}
}

/*
 * Routines to maintain information about directory inodes.
 * This is built during the first pass and used during the
 * second and third passes.
 *
 * Enter inodes into the cache.
 */
struct inoinfo *
cacheino(union dinode *dp, ino_t inumber)
{
	struct inoinfo *inp;
	int i, blks;

	if (getinoinfo(inumber) != NULL)
		pfatal("cacheino: duplicate entry for ino %jd\n",
		    (intmax_t)inumber);
	if (howmany(DIP(dp, di_size), sblock.fs_bsize) > UFS_NDADDR)
		blks = UFS_NDADDR + UFS_NIADDR;
	else if (DIP(dp, di_size) > 0)
		blks = howmany(DIP(dp, di_size), sblock.fs_bsize);
	else
		blks = 1;
	inp = (struct inoinfo *)
		Malloc(sizeof(*inp) + (blks - 1) * sizeof(ufs2_daddr_t));
	if (inp == NULL)
		errx(EEXIT, "cannot increase directory list");
	SLIST_INSERT_HEAD(&inphash[inumber % dirhash], inp, i_hash);
	inp->i_flags = 0;
	inp->i_parent = inumber == UFS_ROOTINO ? UFS_ROOTINO : (ino_t)0;
	inp->i_dotdot = (ino_t)0;
	inp->i_number = inumber;
	inp->i_isize = DIP(dp, di_size);
	inp->i_depth = DIP(dp, di_dirdepth);
	inp->i_numblks = blks;
	for (i = 0; i < MIN(blks, UFS_NDADDR); i++)
		inp->i_blks[i] = DIP(dp, di_db[i]);
	if (blks > UFS_NDADDR)
		for (i = 0; i < UFS_NIADDR; i++)
			inp->i_blks[UFS_NDADDR + i] = DIP(dp, di_ib[i]);
	if (inplast == listmax) {
		listmax += 100;
		inpsort = (struct inoinfo **)reallocarray((char *)inpsort,
		    listmax, sizeof(struct inoinfo *));
		if (inpsort == NULL)
			errx(EEXIT, "cannot increase directory list");
	}
	inpsort[inplast++] = inp;
	return (inp);
}

/*
 * Look up an inode cache structure.
 */
struct inoinfo *
getinoinfo(ino_t inumber)
{
	struct inoinfo *inp;

	SLIST_FOREACH(inp, &inphash[inumber % dirhash], i_hash) {
		if (inp->i_number != inumber)
			continue;
		return (inp);
	}
	return (NULL);
}

/*
 * Remove an entry from the inode cache and disk-order sorted list.
 * Return 0 on success and 1 on failure.
 */
int
removecachedino(ino_t inumber)
{
	struct inoinfo *inp, **inpp;
	char *listtype;

	listtype = "hash";
	SLIST_FOREACH(inp, &inphash[inumber % dirhash], i_hash) {
		if (inp->i_number != inumber)
			continue;
		SLIST_REMOVE(&inphash[inumber % dirhash], inp, inoinfo, i_hash);
		for (inpp = &inpsort[inplast - 1]; inpp >= inpsort; inpp--) {
			if (*inpp != inp)
				continue;
			*inpp = inpsort[inplast - 1];
			inplast--;
			free(inp);
			return (0);
		}
		listtype = "sort";
		break;
	}
	pfatal("removecachedino: entry for ino %jd not found on %s list\n",
	    (intmax_t)inumber, listtype);
	return (1);
}

/*
 * Clean up all the inode cache structure.
 */
void
inocleanup(void)
{
	struct inoinfo **inpp;

	if (inphash == NULL)
		return;
	for (inpp = &inpsort[inplast - 1]; inpp >= inpsort; inpp--)
		free((char *)(*inpp));
	free((char *)inphash);
	inphash = NULL;
	free((char *)inpsort);
	inpsort = NULL;
}

void
inodirty(struct inode *ip)
{

	if (sblock.fs_magic == FS_UFS2_MAGIC)
		ffs_update_dinode_ckhash(&sblock,
		    (struct ufs2_dinode *)ip->i_dp);
	dirty(ip->i_bp);
}

void
clri(struct inodesc *idesc, const char *type, int flag)
{
	union dinode *dp;
	struct inode ip;

	ginode(idesc->id_number, &ip);
	dp = ip.i_dp;
	if (flag == 1) {
		pwarn("%s %s", type,
		    (DIP(dp, di_mode) & IFMT) == IFDIR ? "DIR" : "FILE");
		prtinode(&ip);
		printf("\n");
	}
	if (preen || reply("CLEAR") == 1) {
		if (preen)
			printf(" (CLEARED)\n");
		n_files--;
		if (bkgrdflag == 0) {
			if (idesc->id_type == SNAP) {
				snapremove(idesc->id_number);
				idesc->id_type = ADDR;
			}
			(void)ckinode(dp, idesc);
			inoinfo(idesc->id_number)->ino_state = USTATE;
			clearinode(dp);
			inodirty(&ip);
		} else {
			cmd.value = idesc->id_number;
			cmd.size = -DIP(dp, di_nlink);
			if (debug)
				printf("adjrefcnt ino %ld amt %lld\n",
				    (long)cmd.value, (long long)cmd.size);
			if (sysctl(adjrefcnt, MIBSIZE, 0, 0,
			    &cmd, sizeof cmd) == -1)
				rwerror("ADJUST INODE", cmd.value);
		}
	}
	irelse(&ip);
}

int
findname(struct inodesc *idesc)
{
	struct direct *dirp = idesc->id_dirp;

	if (dirp->d_ino != idesc->id_parent || idesc->id_entryno < 2) {
		idesc->id_entryno++;
		return (KEEPON);
	}
	memmove(idesc->id_name, dirp->d_name, (size_t)dirp->d_namlen + 1);
	return (STOP|FOUND);
}

int
findino(struct inodesc *idesc)
{
	struct direct *dirp = idesc->id_dirp;

	if (dirp->d_ino == 0)
		return (KEEPON);
	if (strcmp(dirp->d_name, idesc->id_name) == 0 &&
	    dirp->d_ino >= UFS_ROOTINO && dirp->d_ino < maxino) {
		idesc->id_parent = dirp->d_ino;
		return (STOP|FOUND);
	}
	return (KEEPON);
}

int
clearentry(struct inodesc *idesc)
{
	struct direct *dirp = idesc->id_dirp;

	if (dirp->d_ino != idesc->id_parent || idesc->id_entryno < 2) {
		idesc->id_entryno++;
		return (KEEPON);
	}
	dirp->d_ino = 0;
	return (STOP|FOUND|ALTERED);
}

void
prtinode(struct inode *ip)
{
	char *p;
	union dinode *dp;
	struct passwd *pw;
	time_t t;

	dp = ip->i_dp;
	printf(" I=%lu ", (u_long)ip->i_number);
	if (ip->i_number < UFS_ROOTINO || ip->i_number >= maxino)
		return;
	printf(" OWNER=");
	if ((pw = getpwuid((int)DIP(dp, di_uid))) != NULL)
		printf("%s ", pw->pw_name);
	else
		printf("%u ", (unsigned)DIP(dp, di_uid));
	printf("MODE=%o\n", DIP(dp, di_mode));
	if (preen)
		printf("%s: ", cdevname);
	printf("SIZE=%ju ", (uintmax_t)DIP(dp, di_size));
	t = DIP(dp, di_mtime);
	if ((p = ctime(&t)) != NULL)
		printf("MTIME=%12.12s %4.4s ", &p[4], &p[20]);
}

void
blkerror(ino_t ino, const char *type, ufs2_daddr_t blk)
{

	pfatal("%jd %s I=%ju", (intmax_t)blk, type, (uintmax_t)ino);
	printf("\n");
	switch (inoinfo(ino)->ino_state) {

	case FSTATE:
	case FZLINK:
		inoinfo(ino)->ino_state = FCLEAR;
		return;

	case DSTATE:
	case DZLINK:
		inoinfo(ino)->ino_state = DCLEAR;
		return;

	case FCLEAR:
	case DCLEAR:
		return;

	default:
		errx(EEXIT, "BAD STATE %d TO BLKERR", inoinfo(ino)->ino_state);
		/* NOTREACHED */
	}
}

/*
 * allocate an unused inode
 */
ino_t
allocino(ino_t request, int type)
{
	ino_t ino;
	struct inode ip;
	union dinode *dp;
	struct bufarea *cgbp;
	struct cg *cgp;
	int cg, anyino;

	anyino = 0;
	if (request == 0) {
		request = UFS_ROOTINO;
		anyino = 1;
	} else if (inoinfo(request)->ino_state != USTATE)
		return (0);
retry:
	for (ino = request; ino < maxino; ino++)
		if (inoinfo(ino)->ino_state == USTATE)
			break;
	if (ino >= maxino)
		return (0);
	cg = ino_to_cg(&sblock, ino);
	cgbp = cglookup(cg);
	cgp = cgbp->b_un.b_cg;
	if (!check_cgmagic(cg, cgbp)) {
		if (anyino == 0)
			return (0);
		request = (cg + 1) * sblock.fs_ipg;
		goto retry;
	}
	setbit(cg_inosused(cgp), ino % sblock.fs_ipg);
	cgp->cg_cs.cs_nifree--;
	switch (type & IFMT) {
	case IFDIR:
		inoinfo(ino)->ino_state = DSTATE;
		cgp->cg_cs.cs_ndir++;
		break;
	case IFREG:
	case IFLNK:
		inoinfo(ino)->ino_state = FSTATE;
		break;
	default:
		return (0);
	}
	cgdirty(cgbp);
	ginode(ino, &ip);
	dp = ip.i_dp;
	memset(dp, 0, ((sblock.fs_magic == FS_UFS1_MAGIC) ?
	    sizeof(struct ufs1_dinode) : sizeof(struct ufs2_dinode)));
	DIP_SET(dp, di_db[0], allocblk(ino_to_cg(&sblock, ino), (long)1,
	    std_checkblkavail));
	if (DIP(dp, di_db[0]) == 0) {
		inoinfo(ino)->ino_state = USTATE;
		inodirty(&ip);
		irelse(&ip);
		return (0);
	}
	DIP_SET(dp, di_mode, type);
	DIP_SET(dp, di_atime, time(NULL));
	DIP_SET(dp, di_ctime, DIP(dp, di_atime));
	DIP_SET(dp, di_mtime, DIP(dp, di_ctime));
	DIP_SET(dp, di_size, sblock.fs_fsize);
	DIP_SET(dp, di_blocks, btodb(sblock.fs_fsize));
	n_files++;
	inodirty(&ip);
	irelse(&ip);
	inoinfo(ino)->ino_type = IFTODT(type);
	return (ino);
}

/*
 * deallocate an inode
 */
void
freeino(ino_t ino)
{
	struct inodesc idesc;
	union dinode *dp;
	struct inode ip;

	memset(&idesc, 0, sizeof(struct inodesc));
	idesc.id_type = ADDR;
	idesc.id_func = freeblock;
	idesc.id_number = ino;
	ginode(ino, &ip);
	dp = ip.i_dp;
	(void)ckinode(dp, &idesc);
	clearinode(dp);
	inodirty(&ip);
	irelse(&ip);
	inoinfo(ino)->ino_state = USTATE;
	n_files--;
}