/* $NetBSD: pass6.c,v 1.51 2020/04/03 19:36:33 joerg Exp $       */

/*-
 * Copyright (c) 2003 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Konrad E. Schroder <perseant@hhhh.org>.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/buf.h>
#include <sys/mount.h>

#define VU_DIROP 0x01000000 /* XXX XXX from sys/vnode.h */
#define vnode uvnode
#include <ufs/lfs/lfs.h>
#include <ufs/lfs/lfs_accessors.h>
#include <ufs/lfs/lfs_inode.h>
#undef vnode

#include <assert.h>
#include <err.h>
#include <signal.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <util.h>

#include "bufcache.h"
#include "lfs_user.h"
#include "segwrite.h"

#include "fsck.h"
#include "extern.h"
#include "fsutil.h"

static int nnewblocks;

/*
 * Our own copy of lfs_update_single so we can account in seg_table
 * as well as the Ifile; and so we can add the blocks to their new
 * segment.
 *
 * Change the given block's address to ndaddr, finding its previous
 * location using ulfs_bmaparray().
 *
 * Account for this change in the segment table.
 */
static void
rfw_update_single(struct uvnode *vp, daddr_t lbn, daddr_t ndaddr, size_t size)
{
        SEGUSE *sup;
        struct ubuf *bp;
        struct indir a[ULFS_NIADDR + 2], *ap;
        struct inode *ip;
        daddr_t daddr, ooff;
        int num, error;
        int i, osize = 0;
        int frags, ofrags = 0;
        u_int32_t oldsn, sn;

        ip = VTOI(vp);
        ip->i_state |= IN_MODIFIED;

        error = ulfs_bmaparray(fs, vp, lbn, &daddr, a, &num);
        if (error)
                errx(1, "lfs_updatemeta: ulfs_bmaparray returned %d"
                     " looking up lbn %" PRId64 "\n", error, lbn);
        if (daddr > 0)
                daddr = LFS_DBTOFSB(fs, daddr);

        frags = lfs_numfrags(fs, size);
        switch (num) {
        case 0:
                ooff = lfs_dino_getdb(fs, ip->i_din, lbn);
                if (ooff <= 0)
                        lfs_dino_setblocks(fs, ip->i_din,
                            lfs_dino_getblocks(fs, ip->i_din) + frags);
                else {
                        /* possible fragment truncation or extension */
                        ofrags = lfs_numfrags(fs, ip->i_lfs_fragsize[lbn]);
                        lfs_dino_setblocks(fs, ip->i_din,
                            lfs_dino_getblocks(fs, ip->i_din) + (frags - ofrags));
                }
                lfs_dino_setdb(fs, ip->i_din, lbn, ndaddr);
                break;
        case 1:
                ooff = lfs_dino_getib(fs, ip->i_din, a[0].in_off);
                if (ooff <= 0)
                        lfs_dino_setblocks(fs, ip->i_din,
                            lfs_dino_getblocks(fs, ip->i_din) + frags);
                lfs_dino_setib(fs, ip->i_din, a[0].in_off, ndaddr);
                break;
        default:
                ap = &a[num - 1];
                if (bread(vp, ap->in_lbn, lfs_sb_getbsize(fs), 0, &bp))
                        errx(1, "lfs_updatemeta: bread bno %" PRId64,
                            ap->in_lbn);

                ooff = lfs_iblock_get(fs, bp->b_data, ap->in_off);
                if (ooff <= 0)
                        lfs_dino_setblocks(fs, ip->i_din,
                            lfs_dino_getblocks(fs, ip->i_din) + frags);
                lfs_iblock_set(fs, bp->b_data, ap->in_off, ndaddr);
                (void) VOP_BWRITE(bp);
        }

        /*
         * Update segment usage information, based on old size
         * and location.
         */
        if (daddr > 0) {
                oldsn = lfs_dtosn(fs, daddr);
                if (lbn >= 0 && lbn < ULFS_NDADDR)
                        osize = ip->i_lfs_fragsize[lbn];
                else
                        osize = lfs_sb_getbsize(fs);
                LFS_SEGENTRY(sup, fs, oldsn, bp);
                seg_table[oldsn].su_nbytes -= osize;
                sup->su_nbytes -= osize;
                if (!(bp->b_flags & B_GATHERED))
                        fs->lfs_flags |= LFS_IFDIRTY;
                LFS_WRITESEGENTRY(sup, fs, oldsn, bp);
                for (i = 0; i < lfs_btofsb(fs, osize); i++)
                        clrbmap(daddr + i);
        }

        /* If block is beyond EOF, update size */
        if (lbn >= 0 && lfs_dino_getsize(fs, ip->i_din) <= (lbn << lfs_sb_getbshift(fs))) {
                lfs_dino_setsize(fs, ip->i_din, (lbn << lfs_sb_getbshift(fs)) + 1);
        }

        /* If block frag size is too large for old EOF, update size */
        if (lbn < ULFS_NDADDR) {
                off_t minsize;

                minsize = (lbn << lfs_sb_getbshift(fs));
                minsize += (size - lfs_sb_getfsize(fs)) + 1;
                if (lfs_dino_getsize(fs, ip->i_din) < minsize)
                        lfs_dino_setsize(fs, ip->i_din, minsize);
        }

        /* Count for the user */
        ++nnewblocks;

        /* Add block to its new segment */
        sn = lfs_dtosn(fs, ndaddr);
        LFS_SEGENTRY(sup, fs, sn, bp);
        seg_table[sn].su_nbytes += size;
        sup->su_nbytes += size;
        if (!(bp->b_flags & B_GATHERED))
                fs->lfs_flags |= LFS_IFDIRTY;
        LFS_WRITESEGENTRY(sup, fs, sn, bp);
        for (i = 0; i < lfs_btofsb(fs, size); i++)
#ifndef VERBOSE_BLOCKMAP
                setbmap(daddr + i);
#else
                setbmap(daddr + i, ip->i_number);
#endif

        /* Check bfree accounting as well */
        if (daddr <= 0) {
                lfs_sb_subbfree(fs, lfs_btofsb(fs, size));
        } else if (size != osize) {
                lfs_sb_subbfree(fs, frags - ofrags);
        }

        /*
         * Now that this block has a new address, and its old
         * segment no longer owns it, we can forget about its
         * old size.
         */
        if (lbn >= 0 && lbn < ULFS_NDADDR)
                ip->i_lfs_fragsize[lbn] = size;
}

/*
 * Remove the vnode from the cache, including any blocks it
 * may hold.  Account the blocks.  Finally account the removal
 * of the inode from its segment.
 */
static void
remove_ino(struct uvnode *vp, ino_t ino)
{
        IFILE *ifp;
        ino_t nextfree;
        SEGUSE *sup;
        CLEANERINFO *cip;
        struct ubuf *bp, *sbp, *cbp;
        struct inodesc idesc;
        daddr_t daddr;

        if (debug)
                pwarn("remove ino %d\n", (int)ino);

        LFS_IENTRY(ifp, fs, ino, bp);
        daddr = lfs_if_getdaddr(fs, ifp);
        if (daddr > 0) {
                lfs_if_setdaddr(fs, ifp, 0);

                LFS_GET_HEADFREE(fs, cip, cbp, &nextfree);
                lfs_if_setnextfree(fs, ifp, nextfree);
                VOP_BWRITE(bp);
                LFS_PUT_HEADFREE(fs, cip, cbp, ino);
                sbdirty();

                if (vp == NULL)
                        vp = lfs_raw_vget(fs, ino, fs->lfs_ivnode->v_fd, daddr);

                LFS_SEGENTRY(sup, fs, lfs_dtosn(fs, daddr), sbp);
                sup->su_nbytes -= DINOSIZE(fs);
                VOP_BWRITE(sbp);
                seg_table[lfs_dtosn(fs, daddr)].su_nbytes -= DINOSIZE(fs);
        } else
                brelse(bp, 0);

        /* Do on-disk accounting */
        if (vp) {
                idesc.id_number = ino;
                idesc.id_func = pass4check; /* Delete dinode and blocks */
                idesc.id_type = ADDR;
                idesc.id_lblkno = 0;
                clri(&idesc, "unknown", 2); /* XXX magic number 2 */
                /* vp has been destroyed */
        }
}

/*
 * Use FIP records to update blocks, if the generation number matches.
 */
static void
pass6harvest(daddr_t daddr, FINFO *fip)
{
        struct uvnode *vp;
        int i;
        size_t size;

        vp = vget(fs, lfs_fi_getino(fs, fip));
        if (vp && vp != fs->lfs_ivnode &&
            lfs_dino_getgen(fs, VTOI(vp)->i_din) == lfs_fi_getversion(fs, fip)) {
                for (i = 0; i < lfs_fi_getnblocks(fs, fip); i++) {
                        size = (i == lfs_fi_getnblocks(fs, fip) - 1 ?
                                lfs_fi_getlastlength(fs, fip) : lfs_sb_getbsize(fs));
                        if (debug)
                                pwarn("ino %ju lbn %jd -> 0x%jx\n",
                                        (uintmax_t)lfs_fi_getino(fs, fip),
                                        (intmax_t)lfs_fi_getblock(fs, fip, i),
                                        (intmax_t)daddr);
                        rfw_update_single(vp, lfs_fi_getblock(fs, fip, i), daddr, size);
                        daddr += lfs_btofsb(fs, size);
                }
        }
}

/*
 * Check validity of blocks on roll-forward inodes.
 */
int
pass6check(struct inodesc * idesc)
{
        int i, sn, anyout, anynew;

        /* Brand new blocks are always OK */
        if (idesc->id_blkno == UNWRITTEN)
                return KEEPON;

        /* Check that the blocks do not lie within clean segments. */
        anyout = anynew = 0;
        for (i = 0; i < idesc->id_numfrags; i++) {
                sn = lfs_dtosn(fs, idesc->id_blkno + i);
                if (sn < 0 || sn >= lfs_sb_getnseg(fs) ||
                    (seg_table[sn].su_flags & SEGUSE_DIRTY) == 0) {
                        anyout = 1;
                        break;
                }
                if (seg_table[sn].su_flags & SEGUSE_ACTIVE) {
                        if (sn != lfs_dtosn(fs, lfs_sb_getoffset(fs)) ||
                            idesc->id_blkno > lfs_sb_getoffset(fs)) {
                                ++anynew;
                        }
                }
                if (!anynew) {
                        /* Clear so pass1check won't be surprised */
                        clrbmap(idesc->id_blkno + i);
                        seg_table[sn].su_nbytes -= lfs_fsbtob(fs, 1);
                }
        }
        if (anyout) {
                blkerror(idesc->id_number, "BAD", idesc->id_blkno);
                if (badblkcount++ >= MAXBAD) {
                        pwarn("EXCESSIVE BAD BLKS I=%llu",
                            (unsigned long long)idesc->id_number);
                        if (preen)
                                pwarn(" (SKIPPING)\n");
                        else if (reply("CONTINUE") == 0)
                                err(EEXIT, "%s", "");
                        return (STOP);
                }
        }

        return pass1check(idesc);
}

static void
account_indir(struct uvnode *vp, union lfs_dinode *dp, daddr_t ilbn, daddr_t daddr, int lvl)
{
        struct ubuf *bp;
        int32_t *dap, *odap, *buf, *obuf;
        daddr_t lbn;

        if (lvl == 0)
                lbn = -ilbn;
        else
                lbn = ilbn + 1;
        bread(fs->lfs_devvp, LFS_FSBTODB(fs, daddr), lfs_sb_getbsize(fs), 0, &bp);
        buf = emalloc(lfs_sb_getbsize(fs));
        memcpy(buf, bp->b_data, lfs_sb_getbsize(fs));
        brelse(bp, 0);

        obuf = emalloc(lfs_sb_getbsize(fs));
        if (vp) {
                bread(vp, ilbn, lfs_sb_getbsize(fs), 0, &bp);
                memcpy(obuf, bp->b_data, lfs_sb_getbsize(fs));
                brelse(bp, 0);
        } else
                memset(obuf, 0, lfs_sb_getbsize(fs));

        for (dap = buf, odap = obuf;
             dap < (int32_t *)((char *)buf + lfs_sb_getbsize(fs));
             ++dap, ++odap) {
                if (*dap > 0 && *dap != *odap) {
                        rfw_update_single(vp, lbn, *dap, lfs_dblksize(fs, dp, lbn));
                        if (lvl > 0)
                                account_indir(vp, dp, lbn, *dap, lvl - 1);
                }
                if (lvl == 0)
                        ++lbn;
                else if (lvl == 1)
                        lbn -= LFS_NINDIR(fs);
                else if (lvl == 2)
                        lbn -= LFS_NINDIR(fs) * LFS_NINDIR(fs);
        }

        free(obuf);
        free(buf);
}

/*
 * Account block changes between new found inode and existing inode.
 */
static void
account_block_changes(union lfs_dinode *dp)
{
        int i;
        daddr_t lbn, off, odaddr;
        struct uvnode *vp;
        struct inode *ip;

        vp = vget(fs, lfs_dino_getinumber(fs, dp));
        ip = (vp ? VTOI(vp) : NULL);

        /* Check direct block holdings between existing and new */
        for (i = 0; i < ULFS_NDADDR; i++) {
                odaddr = (ip ? lfs_dino_getdb(fs, ip->i_din, i) : 0x0);
                if (lfs_dino_getdb(fs, dp, i) > 0 && lfs_dino_getdb(fs, dp, i) != odaddr)
                        rfw_update_single(vp, i, lfs_dino_getdb(fs, dp, i),
                                          lfs_dblksize(fs, dp, i));
        }

        /* Check indirect block holdings between existing and new */
        off = 0;
        for (i = 0; i < ULFS_NIADDR; i++) {
                odaddr = (ip ? lfs_dino_getib(fs, ip->i_din, i) : 0x0);
                if (lfs_dino_getib(fs, dp, i) > 0 && lfs_dino_getib(fs, dp, i) != odaddr) {
                        lbn = -(ULFS_NDADDR + off + i);
                        rfw_update_single(vp, i, lfs_dino_getib(fs, dp, i), lfs_sb_getbsize(fs));
                        account_indir(vp, dp, lbn, lfs_dino_getib(fs, dp, i), i);
                }
                if (off == 0)
                        off = LFS_NINDIR(fs);
                else
                        off *= LFS_NINDIR(fs);
        }
}

/*
 * Give a previously allocated inode a new address; do segment
 * accounting if necessary.
 *
 * Caller has ensured that this inode is not on the free list, so no
 * free list accounting is done.
 */
static void
readdress_inode(union lfs_dinode *dp, daddr_t daddr)
{
        IFILE *ifp;
        SEGUSE *sup;
        struct ubuf *bp;
        int sn;
        daddr_t odaddr;
        ino_t thisino = lfs_dino_getinumber(fs, dp);
        struct uvnode *vp;

        /* Recursively check all block holdings, account changes */
        account_block_changes(dp);

        /* Move ifile pointer to this location */
        LFS_IENTRY(ifp, fs, thisino, bp);
        odaddr = lfs_if_getdaddr(fs, ifp);
        assert(odaddr != 0);
        lfs_if_setdaddr(fs, ifp, daddr);
        VOP_BWRITE(bp);

        if (debug)
                pwarn("readdress ino %ju from 0x%jx to 0x%jx mode %o nlink %d\n",
                        (uintmax_t)lfs_dino_getinumber(fs, dp),
                        (uintmax_t)odaddr,
                        (intmax_t)daddr,
                        (int)lfs_dino_getmode(fs, dp),
                        (int)lfs_dino_getnlink(fs, dp));

        /* Copy over preexisting in-core inode, if any */
        vp = vget(fs, thisino);
        lfs_copy_dinode(fs, VTOI(vp)->i_din, dp);

        /* Finally account the inode itself */
        sn = lfs_dtosn(fs, odaddr);
        LFS_SEGENTRY(sup, fs, sn, bp);
        sup->su_nbytes -= DINOSIZE(fs);
        VOP_BWRITE(bp);
        seg_table[sn].su_nbytes -= DINOSIZE(fs);

        sn = lfs_dtosn(fs, daddr);
        LFS_SEGENTRY(sup, fs, sn, bp);
        sup->su_nbytes += DINOSIZE(fs);
        VOP_BWRITE(bp);
        seg_table[sn].su_nbytes += DINOSIZE(fs);
}

/*
 * Allocate the given inode from the free list.
 */
static void
alloc_inode(ino_t thisino, daddr_t daddr)
{
        ino_t ino, nextfree, oldhead;
        IFILE *ifp;
        SEGUSE *sup;
        struct ubuf *bp, *cbp;
        CLEANERINFO *cip;

        if (debug)
                pwarn("allocating ino %ju at 0x%jx\n", (uintmax_t)thisino,
                        (intmax_t)daddr);
        while (thisino >= maxino) {
                extend_ifile(fs);
        }

        LFS_IENTRY(ifp, fs, thisino, bp);
        if (lfs_if_getdaddr(fs, ifp) != 0) {
                pwarn("allocated inode %lld already allocated\n",
                        (long long)thisino);
        }
        nextfree = lfs_if_getnextfree(fs, ifp);
        lfs_if_setnextfree(fs, ifp, 0);
        lfs_if_setdaddr(fs, ifp, daddr);
        VOP_BWRITE(bp);

        LFS_GET_HEADFREE(fs, cip, cbp, &oldhead);
        if (oldhead == thisino) {
                LFS_PUT_HEADFREE(fs, cip, cbp, nextfree);
                sbdirty();
                if (nextfree == 0) {
                        extend_ifile(fs);
                }
        } else {
                /* Search the free list for this inode */
                ino = oldhead;
                while (ino) {
                        LFS_IENTRY(ifp, fs, ino, bp);
                        assert(lfs_if_getnextfree(fs, ifp) != ino);
                        if (lfs_if_getnextfree(fs, ifp) == thisino) {
                                lfs_if_setnextfree(fs, ifp, nextfree);
                                VOP_BWRITE(bp);
                                if (nextfree == 0)
                                        LFS_PUT_TAILFREE(fs, cip, cbp, ino);
                                break;
                        } else
                                ino = lfs_if_getnextfree(fs, ifp);
                        brelse(bp, 0);
                }
        }
        
        /* Account for new location */
        LFS_SEGENTRY(sup, fs, lfs_dtosn(fs, daddr), bp);
        sup->su_nbytes += DINOSIZE(fs);
        VOP_BWRITE(bp);
        seg_table[lfs_dtosn(fs, daddr)].su_nbytes += DINOSIZE(fs);
}

/*
 * Roll forward from the last verified checkpoint.
 *
 * Basic strategy:
 *
 * Run through the summaries finding the last valid partial segment.
 * Note segment numbers as we go.  For each inode that we find, compare
 * its generation number; if newer than old inode's (or if old inode is
 * USTATE), change to that inode.  Recursively look at inode blocks that
 * do not have their old disk addresses.  These addresses must lie in
 * segments we have seen already in our roll forward.
 *
 * A second pass through the past-checkpoint area verifies the validity
 * of these new blocks, as well as updating other blocks that do not
 * have corresponding new inodes (but their generation number must match
 * the old generation number).
 */
void
pass6(void)
{
        daddr_t daddr, ibdaddr, odaddr, lastgood;
        IINFO *iip;
        struct uvnode *vp, *devvp;
        CLEANERINFO *cip;
        SEGUSE *sup;
        SEGSUM *sp;
        struct ubuf *bp, *ibp, *sbp, *cbp;
        union lfs_dinode *dp;
        struct inodesc idesc;
        int i, j, bc, hassuper;
        unsigned k;
        int nnewfiles, ndelfiles, nmvfiles;
        int sn, curseg;
        char *ibbuf;
        long lastserial;

        devvp = fs->lfs_devvp;

        /* If we can't roll forward because of created files, don't try */
        if (no_roll_forward) {
                if (debug)
                        pwarn("not rolling forward due to possible allocation conflict\n");
                return;
        }

        /* Find last valid partial segment */
        lastgood = try_verify(fs, devvp, 0, debug);
        if (lastgood == lfs_sb_getoffset(fs)) {
                if (debug)
                        pwarn("not rolling forward, nothing to recover\n");
                return;
        }

        if (debug)
                pwarn("could roll forward from 0x%jx to 0x%jx\n",
                        (uintmax_t)lfs_sb_getoffset(fs), (uintmax_t)lastgood);

        if (!preen && reply("ROLL FORWARD") == 0)
                return;
        /*
         * Pass 1: find inode blocks.  We ignore the Ifile inode but accept
         * changes to any other inode.
         */

        ibbuf = emalloc(lfs_sb_getibsize(fs));
        nnewfiles = ndelfiles = nmvfiles = nnewblocks = 0;
        daddr = lfs_sb_getoffset(fs);
        hassuper = 0;
        lastserial = 0;
        while (daddr != lastgood) {
                seg_table[lfs_dtosn(fs, daddr)].su_flags |= SEGUSE_DIRTY | SEGUSE_ACTIVE;
                LFS_SEGENTRY(sup, fs, lfs_dtosn(fs, daddr), sbp);
                sup->su_flags |= SEGUSE_DIRTY;
                VOP_BWRITE(sbp);

                /* Could be a superblock */
                if (lfs_sntod(fs, lfs_dtosn(fs, daddr)) == daddr) {
                        if (daddr == lfs_sb_gets0addr(fs)) {
                                ++hassuper;
                                daddr += lfs_btofsb(fs, LFS_LABELPAD);
                        }
                        for (i = 0; i < LFS_MAXNUMSB; i++) {
                                if (daddr == lfs_sb_getsboff(fs, i)) {
                                        ++hassuper;
                                        daddr += lfs_btofsb(fs, LFS_SBPAD);     
                                }
                                if (daddr < lfs_sb_getsboff(fs, i))
                                        break;
                        }
                }
                KASSERT(hassuper == 0 || hassuper == 1);
                
                /* Read in summary block */
                bread(devvp, LFS_FSBTODB(fs, daddr), lfs_sb_getsumsize(fs), 0, &bp);
                sp = (SEGSUM *)bp->b_data;
                if (debug)
                        pwarn("sum at 0x%jx: ninos=%d nfinfo=%d\n",
                                (intmax_t)daddr, (int)lfs_ss_getninos(fs, sp),
                                (int)lfs_ss_getnfinfo(fs, sp));

                /* We have verified that this is a good summary. */
                LFS_SEGENTRY(sup, fs, lfs_dtosn(fs, daddr), sbp);
                ++sup->su_nsums;
                VOP_BWRITE(sbp);
                lfs_sb_subbfree(fs, lfs_btofsb(fs, lfs_sb_getsumsize(fs)));
                lfs_sb_adddmeta(fs, lfs_btofsb(fs, lfs_sb_getsumsize(fs)));
                sbdirty();
                if (lfs_sntod(fs, lfs_dtosn(fs, daddr)) == daddr +
                    hassuper * lfs_btofsb(fs, LFS_SBPAD) &&
                    lfs_dtosn(fs, daddr) != lfs_dtosn(fs, lfs_sb_getoffset(fs))) {
                        lfs_sb_subnclean(fs, 1);
                        sbdirty();
                }

                /* Find inodes, look at generation number. */
                if (lfs_ss_getninos(fs, sp)) {
                        LFS_SEGENTRY(sup, fs, lfs_dtosn(fs, daddr), sbp);
                        sup->su_ninos += howmany(lfs_ss_getninos(fs, sp), LFS_INOPB(fs));
                        VOP_BWRITE(sbp);
                        lfs_sb_adddmeta(fs, lfs_btofsb(fs, howmany(lfs_ss_getninos(fs, sp),
                                                            LFS_INOPB(fs)) *
                                                lfs_sb_getibsize(fs)));
                }
                iip = SEGSUM_IINFOSTART(fs, bp->b_data);
                for (i = 0; i < howmany(lfs_ss_getninos(fs, sp), LFS_INOPB(fs)); i++) {
                        ino_t *inums;
                        
                        inums = ecalloc(LFS_INOPB(fs) + 1, sizeof(*inums));
                        ibdaddr = lfs_ii_getblock(fs, iip);
                        iip = NEXTLOWER_IINFO(fs, iip);
                        lfs_sb_subbfree(fs, lfs_btofsb(fs, lfs_sb_getibsize(fs)));
                        sbdirty();
                        bread(devvp, LFS_FSBTODB(fs, ibdaddr),
                              lfs_sb_getibsize(fs), 0, &ibp);
                        memcpy(ibbuf, ibp->b_data, lfs_sb_getibsize(fs));
                        brelse(ibp, 0);

                        j = 0;
                        for (k = 0; k < LFS_INOPB(fs); k++) {
                                dp = DINO_IN_BLOCK(fs, ibbuf, k);
                                if (lfs_dino_getinumber(fs, dp) == 0 ||
                                    lfs_dino_getinumber(fs, dp) == LFS_IFILE_INUM)
                                        continue;
                                /* Basic sanity checks */
                                if (lfs_dino_getnlink(fs, dp) < 0 
#if 0
                                    || lfs_dino_getinumber(fs, dp) < 0
                                    || lfs_dino_getsize(fs, dp) < 0
#endif
                                ) {
                                        pwarn("BAD INODE AT 0x%jx\n",
                                                (intmax_t)ibdaddr);
                                        brelse(bp, 0);
                                        free(inums);
                                        goto out;
                                }

                                vp = vget(fs, lfs_dino_getinumber(fs, dp));

                                /*
                                 * Four cases:
                                 * (1) Invalid inode (nlink == 0).
                                 *     If currently allocated, remove.
                                 */
                                if (lfs_dino_getnlink(fs, dp) == 0) {
                                        remove_ino(vp, lfs_dino_getinumber(fs, dp));
                                        ++ndelfiles;
                                        continue;
                                }
                                /*
                                 * (2) New valid inode, previously free.
                                 *     Nothing to do except account
                                 *     the inode itself, done after the
                                 *     loop.
                                 */
                                if (vp == NULL) {
                                        if (!(lfs_ss_getflags(fs, sp) & SS_DIROP))
                                                pfatal("NEW FILE IN NON-DIROP PARTIAL SEGMENT");
                                        else {
                                                inums[j++] = lfs_dino_getinumber(fs, dp);
                                                nnewfiles++;
                                        }
                                        continue;
                                }
                                /*
                                 * (3) Valid new version of previously
                                 *     allocated inode.  Delete old file
                                 *     and proceed as in (2).
                                 */
                                if (vp &&
                                    lfs_dino_getgen(fs, VTOI(vp)->i_din)
                                    < lfs_dino_getgen(fs, dp)) {
                                        remove_ino(vp, lfs_dino_getinumber(fs, dp));
                                        if (!(lfs_ss_getflags(fs, sp) & SS_DIROP))
                                                pfatal("NEW FILE VERSION IN NON-DIROP PARTIAL SEGMENT");
                                        else {
                                                inums[j++] = lfs_dino_getinumber(fs, dp);
                                                ndelfiles++;
                                                nnewfiles++;
                                        }
                                        continue;
                                }
                                /*
                                 * (4) Same version of previously
                                 *     allocated inode.  Move inode to
                                 *     this location, account inode change
                                 *     only.  We'll pick up any new
                                 *     blocks when we do the block pass.
                                 */
                                if (vp &&
                                    lfs_dino_getgen(fs, VTOI(vp)->i_din)
                                    == lfs_dino_getgen(fs, dp)) {
                                        nmvfiles++;
                                        readdress_inode(dp, ibdaddr);

                                        /* Update with new info */
                                        lfs_dino_setmode(fs, VTOD(vp), lfs_dino_getmode(fs, dp));
                                        lfs_dino_setnlink(fs, VTOD(vp), lfs_dino_getmode(fs, dp));
                                        /* XXX size is important */
                                        lfs_dino_setsize(fs, VTOD(vp), lfs_dino_getsize(fs, dp));
                                        lfs_dino_setatime(fs, VTOD(vp), lfs_dino_getatime(fs, dp));
                                        lfs_dino_setatimensec(fs, VTOD(vp), lfs_dino_getatimensec(fs, dp));
                                        lfs_dino_setmtime(fs, VTOD(vp), lfs_dino_getmtime(fs, dp));
                                        lfs_dino_setmtimensec(fs, VTOD(vp), lfs_dino_getmtimensec(fs, dp));
                                        lfs_dino_setctime(fs, VTOD(vp), lfs_dino_getctime(fs, dp));
                                        lfs_dino_setctimensec(fs, VTOD(vp), lfs_dino_getctimensec(fs, dp));
                                        lfs_dino_setflags(fs, VTOD(vp), lfs_dino_getflags(fs, dp));
                                        lfs_dino_setuid(fs, VTOD(vp), lfs_dino_getuid(fs, dp));
                                        lfs_dino_setgid(fs, VTOD(vp), lfs_dino_getgid(fs, dp));
                                        inodirty(VTOI(vp));
                                }
                        }
                        for (j = 0; inums[j]; j++) {
                                alloc_inode(inums[j], ibdaddr);
                                vp = lfs_raw_vget(fs, inums[j],
                                              devvp->v_fd, ibdaddr);
                                /* We'll get the blocks later */
                                if (debug)
                                        pwarn("alloc ino %d nlink %d\n",
                                                (int)inums[j], lfs_dino_getnlink(fs, VTOD(vp)));

                                for (k=0; k<ULFS_NDADDR; k++) {
                                        lfs_dino_setdb(fs, VTOD(vp), k, 0);
                                }
                                for (k=0; k<ULFS_NIADDR; k++) {
                                        lfs_dino_setib(fs, VTOD(vp), k, 0);
                                }
                                lfs_dino_setblocks(fs, VTOD(vp), 0);

                                vp->v_uflag |= VU_DIROP;
                                inodirty(VTOI(vp));
                        }
                        free(inums);
                }

                bc = check_summary(fs, sp, daddr, debug, devvp, NULL);
                if (bc == 0) {
                        pwarn("unexpected bad seg ptr at 0x%jx with serial=%ju\n",
                                (intmax_t)daddr, (uintmax_t)lfs_ss_getserial(fs, sp));
                        brelse(bp, 0);
                        break;
                } else {
                        if (debug)
                                pwarn("good seg ptr at 0x%jx with serial=%ju\n",
                                        (intmax_t)daddr, (uintmax_t)lfs_ss_getserial(fs, sp));
                        lastserial = lfs_ss_getserial(fs, sp);
                }
                odaddr = daddr;
                daddr += lfs_btofsb(fs, lfs_sb_getsumsize(fs) + bc);
                if (lfs_dtosn(fs, odaddr) != lfs_dtosn(fs, daddr) ||
                    lfs_dtosn(fs, daddr) != lfs_dtosn(fs, daddr +
                        lfs_btofsb(fs, lfs_sb_getsumsize(fs) + lfs_sb_getbsize(fs)) - 1)) {
                        daddr = lfs_ss_getnext(fs, sp);
                }
                brelse(bp, 0);
        }

    out:
        free(ibbuf);

        /* Set serial here, just to be sure (XXX should be right already) */
        lfs_sb_setserial(fs, lastserial + 1);

        /*
         * Check our new vnodes.  Any blocks must lie in segments that
         * we've seen before (SEGUSE_DIRTY or SEGUSE_RFW); and the rest
         * of the pass 1 checks as well.
         */
        memset(&idesc, 0, sizeof(struct inodesc));
        idesc.id_type = ADDR;
        idesc.id_func = pass6check;
        idesc.id_lblkno = 0;
        LIST_FOREACH(vp, &vnodelist, v_mntvnodes) {
                if ((vp->v_uflag & VU_DIROP) == 0)
                        --n_files; /* Don't double count */
                checkinode(VTOI(vp)->i_number, &idesc);
        }

        /*
         * Second pass.  Run through FINFO entries looking for blocks
         * with the same generation number as files we've seen before.
         * If they have it, pretend like we just wrote them.  We don't
         * do the pretend-write, though, if we've already seen them
         * (the accounting would have been done for us already).
         */
        daddr = lfs_sb_getoffset(fs);
        while (daddr != lastgood) {
                if (!(seg_table[lfs_dtosn(fs, daddr)].su_flags & SEGUSE_DIRTY)) {
                        seg_table[lfs_dtosn(fs, daddr)].su_flags |= SEGUSE_DIRTY;
                        LFS_SEGENTRY(sup, fs, lfs_dtosn(fs, daddr), sbp);
                        sup->su_flags |= SEGUSE_DIRTY;
                        VOP_BWRITE(sbp);
                }

                /* Could be a superblock */
                if (lfs_sntod(fs, lfs_dtosn(fs, daddr)) == daddr) {
                        if (daddr == lfs_sb_gets0addr(fs))
                                daddr += lfs_btofsb(fs, LFS_LABELPAD);
                        for (i = 0; i < LFS_MAXNUMSB; i++) {
                                if (daddr == lfs_sb_getsboff(fs, i)) {
                                        daddr += lfs_btofsb(fs, LFS_SBPAD);     
                                }
                                if (daddr < lfs_sb_getsboff(fs, i))
                                        break;
                        }
                }
                
                /* Read in summary block */
                bread(devvp, LFS_FSBTODB(fs, daddr), lfs_sb_getsumsize(fs), 0, &bp);
                sp = (SEGSUM *)bp->b_data;
                bc = check_summary(fs, sp, daddr, debug, devvp, pass6harvest);
                if (bc == 0) {
                        pwarn("unexpected bad seg ptr [2] at 0x%jx with serial=%ju\n",
                                (intmax_t)daddr, (uintmax_t)lfs_ss_getserial(fs, sp));
                        brelse(bp, 0);
                        break;
                }
                odaddr = daddr;
                daddr += lfs_btofsb(fs, lfs_sb_getsumsize(fs) + bc);
                lfs_sb_subavail(fs, lfs_btofsb(fs, lfs_sb_getsumsize(fs) + bc));
                if (lfs_dtosn(fs, odaddr) != lfs_dtosn(fs, daddr) ||
                    lfs_dtosn(fs, daddr) != lfs_dtosn(fs, daddr +
                        lfs_btofsb(fs, lfs_sb_getsumsize(fs) + lfs_sb_getbsize(fs)) - 1)) {
                        lfs_sb_subavail(fs, lfs_sntod(fs, lfs_dtosn(fs, daddr) + 1) - daddr);
                        daddr = lfs_ss_getnext(fs, sp);
                }
                LFS_CLEANERINFO(cip, fs, cbp);
                LFS_SYNC_CLEANERINFO(cip, fs, cbp, 0);
                bp->b_flags |= B_AGE;
                brelse(bp, 0);
        }

        /* Final address could also be a superblock */
        if (lfs_sntod(fs, lfs_dtosn(fs, lastgood)) == lastgood) {
                if (lastgood == lfs_sb_gets0addr(fs))
                        lastgood += lfs_btofsb(fs, LFS_LABELPAD);
                for (i = 0; i < LFS_MAXNUMSB; i++) {
                        if (lastgood == lfs_sb_getsboff(fs, i))
                                lastgood += lfs_btofsb(fs, LFS_SBPAD);  
                        if (lastgood < lfs_sb_getsboff(fs, i))
                                break;
                }
        }
                
        /* Update offset to point at correct location */
        lfs_sb_setoffset(fs, lastgood);
        lfs_sb_setcurseg(fs, lfs_sntod(fs, lfs_dtosn(fs, lastgood)));
        for (sn = curseg = lfs_dtosn(fs, lfs_sb_getcurseg(fs));;) {
                sn = (sn + 1) % lfs_sb_getnseg(fs);
                if (sn == curseg)
                        errx(1, "no clean segments");
                LFS_SEGENTRY(sup, fs, sn, bp);
                if ((sup->su_flags & SEGUSE_DIRTY) == 0) {
                        sup->su_flags |= SEGUSE_DIRTY | SEGUSE_ACTIVE;
                        VOP_BWRITE(bp);
                        break;
                }
                brelse(bp, 0);
        }
        lfs_sb_setnextseg(fs, lfs_sntod(fs, sn));

        if (preen) {
                if (ndelfiles)
                        pwarn("roll forward deleted %d file%s\n", ndelfiles,
                                (ndelfiles > 1 ? "s" : ""));
                if (nnewfiles)
                        pwarn("roll forward added %d file%s\n", nnewfiles,
                                (nnewfiles > 1 ? "s" : ""));
                if (nmvfiles)
                        pwarn("roll forward relocated %d inode%s\n", nmvfiles,
                                (nmvfiles > 1 ? "s" : ""));
                if (nnewblocks)
                        pwarn("roll forward verified %d data block%s\n", nnewblocks,
                                (nnewblocks > 1 ? "s" : ""));
                if (ndelfiles == 0 && nnewfiles == 0 && nmvfiles == 0 &&
                    nnewblocks == 0)
                        pwarn("roll forward produced nothing new\n");
        }

        if (!preen) {
                /* Run pass 5 again (it's quick anyway). */
                pwarn("** Phase 6b - Recheck Segment Block Accounting\n");
                pass5();
        }

        /* Likewise for pass 0 */
        if (!preen)
                pwarn("** Phase 6c - Recheck Inode Free List\n");
        pass0();
}