Add a flags parameter to the ffs_sbget() function that reads UFS superblocks.

[FreeBSD/FreeBSD.git] / sbin / fsck_ffs / suj.c

/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright 2009, 2010 Jeffrey W. Roberson <jeff@FreeBSD.org>
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/disk.h>
#include <sys/disklabel.h>
#include <sys/mount.h>
#include <sys/stat.h>

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

#include <assert.h>
#include <err.h>
#include <setjmp.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <libufs.h>
#include <string.h>
#include <strings.h>
#include <sysexits.h>
#include <time.h>

#include "fsck.h"

#define DOTDOT_OFFSET   DIRECTSIZ(1)

struct suj_seg {
        TAILQ_ENTRY(suj_seg) ss_next;
        struct jsegrec  ss_rec;
        uint8_t         *ss_blk;
};

struct suj_rec {
        TAILQ_ENTRY(suj_rec) sr_next;
        union jrec      *sr_rec;
};
TAILQ_HEAD(srechd, suj_rec);

struct suj_ino {
        LIST_ENTRY(suj_ino)     si_next;
        struct srechd           si_recs;
        struct srechd           si_newrecs;
        struct srechd           si_movs;
        struct jtrncrec         *si_trunc;
        ino_t                   si_ino;
        char                    si_skipparent;
        char                    si_hasrecs;
        char                    si_blkadj;
        char                    si_linkadj;
        int                     si_mode;
        nlink_t                 si_nlinkadj;
        nlink_t                 si_nlink;
        nlink_t                 si_dotlinks;
};
LIST_HEAD(inohd, suj_ino);

struct suj_blk {
        LIST_ENTRY(suj_blk)     sb_next;
        struct srechd           sb_recs;
        ufs2_daddr_t            sb_blk;
};
LIST_HEAD(blkhd, suj_blk);

struct suj_cg {
        LIST_ENTRY(suj_cg)      sc_next;
        struct blkhd            sc_blkhash[HASHSIZE];
        struct inohd            sc_inohash[HASHSIZE];
        struct ino_blk          *sc_lastiblk;
        struct suj_ino          *sc_lastino;
        struct suj_blk          *sc_lastblk;
        struct bufarea          *sc_cgbp;
        struct cg               *sc_cgp;
        int                     sc_cgx;
};

static LIST_HEAD(cghd, suj_cg) cghash[HASHSIZE];
static struct suj_cg *lastcg;

static TAILQ_HEAD(seghd, suj_seg) allsegs;
static uint64_t oldseq;
static struct fs *fs = NULL;
static ino_t sujino;

/*
 * Summary statistics.
 */
static uint64_t freefrags;
static uint64_t freeblocks;
static uint64_t freeinos;
static uint64_t freedir;
static uint64_t jbytes;
static uint64_t jrecs;

static jmp_buf  jmpbuf;

typedef void (*ino_visitor)(ino_t, ufs_lbn_t, ufs2_daddr_t, int);
static void err_suj(const char *, ...) __dead2;
static void ino_trunc(ino_t, off_t);
static void ino_decr(ino_t);
static void ino_adjust(struct suj_ino *);
static void ino_build(struct suj_ino *);
static int blk_isfree(ufs2_daddr_t);
static void initsuj(void);

static void *
errmalloc(size_t n)
{
        void *a;

        a = Malloc(n);
        if (a == NULL)
                err(EX_OSERR, "malloc(%zu)", n);
        return (a);
}

/*
 * When hit a fatal error in journalling check, print out
 * the error and then offer to fallback to normal fsck.
 */
static void
err_suj(const char * restrict fmt, ...)
{
        va_list ap;

        if (preen)
                (void)fprintf(stdout, "%s: ", cdevname);

        va_start(ap, fmt);
        (void)vfprintf(stdout, fmt, ap);
        va_end(ap);

        longjmp(jmpbuf, -1);
}

/*
 * Lookup a cg by number in the hash so we can keep track of which cgs
 * need stats rebuilt.
 */
static struct suj_cg *
cg_lookup(int cgx)
{
        struct cghd *hd;
        struct suj_cg *sc;
        struct bufarea *cgbp;

        if (cgx < 0 || cgx >= fs->fs_ncg)
                err_suj("Bad cg number %d\n", cgx);
        if (lastcg && lastcg->sc_cgx == cgx)
                return (lastcg);
        cgbp = cglookup(cgx);
        if (!check_cgmagic(cgx, cgbp, 0))
                err_suj("UNABLE TO REBUILD CYLINDER GROUP %d", cgx);
        hd = &cghash[HASH(cgx)];
        LIST_FOREACH(sc, hd, sc_next)
                if (sc->sc_cgx == cgx) {
                        sc->sc_cgbp = cgbp;
                        sc->sc_cgp = sc->sc_cgbp->b_un.b_cg;
                        lastcg = sc;
                        return (sc);
                }
        sc = errmalloc(sizeof(*sc));
        bzero(sc, sizeof(*sc));
        sc->sc_cgbp = cgbp;
        sc->sc_cgp = sc->sc_cgbp->b_un.b_cg;
        sc->sc_cgx = cgx;
        LIST_INSERT_HEAD(hd, sc, sc_next);
        return (sc);
}

/*
 * Lookup an inode number in the hash and allocate a suj_ino if it does
 * not exist.
 */
static struct suj_ino *
ino_lookup(ino_t ino, int creat)
{
        struct suj_ino *sino;
        struct inohd *hd;
        struct suj_cg *sc;

        sc = cg_lookup(ino_to_cg(fs, ino));
        if (sc->sc_lastino && sc->sc_lastino->si_ino == ino)
                return (sc->sc_lastino);
        hd = &sc->sc_inohash[HASH(ino)];
        LIST_FOREACH(sino, hd, si_next)
                if (sino->si_ino == ino)
                        return (sino);
        if (creat == 0)
                return (NULL);
        sino = errmalloc(sizeof(*sino));
        bzero(sino, sizeof(*sino));
        sino->si_ino = ino;
        TAILQ_INIT(&sino->si_recs);
        TAILQ_INIT(&sino->si_newrecs);
        TAILQ_INIT(&sino->si_movs);
        LIST_INSERT_HEAD(hd, sino, si_next);

        return (sino);
}

/*
 * Lookup a block number in the hash and allocate a suj_blk if it does
 * not exist.
 */
static struct suj_blk *
blk_lookup(ufs2_daddr_t blk, int creat)
{
        struct suj_blk *sblk;
        struct suj_cg *sc;
        struct blkhd *hd;

        sc = cg_lookup(dtog(fs, blk));
        if (sc->sc_lastblk && sc->sc_lastblk->sb_blk == blk)
                return (sc->sc_lastblk);
        hd = &sc->sc_blkhash[HASH(fragstoblks(fs, blk))];
        LIST_FOREACH(sblk, hd, sb_next)
                if (sblk->sb_blk == blk)
                        return (sblk);
        if (creat == 0)
                return (NULL);
        sblk = errmalloc(sizeof(*sblk));
        bzero(sblk, sizeof(*sblk));
        sblk->sb_blk = blk;
        TAILQ_INIT(&sblk->sb_recs);
        LIST_INSERT_HEAD(hd, sblk, sb_next);

        return (sblk);
}

static int
blk_overlaps(struct jblkrec *brec, ufs2_daddr_t start, int frags)
{
        ufs2_daddr_t bstart;
        ufs2_daddr_t bend;
        ufs2_daddr_t end;

        end = start + frags;
        bstart = brec->jb_blkno + brec->jb_oldfrags;
        bend = bstart + brec->jb_frags;
        if (start < bend && end > bstart)
                return (1);
        return (0);
}

static int
blk_equals(struct jblkrec *brec, ino_t ino, ufs_lbn_t lbn, ufs2_daddr_t start,
    int frags)
{

        if (brec->jb_ino != ino || brec->jb_lbn != lbn)
                return (0);
        if (brec->jb_blkno + brec->jb_oldfrags != start)
                return (0);
        if (brec->jb_frags < frags)
                return (0);
        return (1);
}

static void
blk_setmask(struct jblkrec *brec, int *mask)
{
        int i;

        for (i = brec->jb_oldfrags; i < brec->jb_oldfrags + brec->jb_frags; i++)
                *mask |= 1 << i;
}

/*
 * Determine whether a given block has been reallocated to a new location.
 * Returns a mask of overlapping bits if any frags have been reused or
 * zero if the block has not been re-used and the contents can be trusted.
 *
 * This is used to ensure that an orphaned pointer due to truncate is safe
 * to be freed.  The mask value can be used to free partial blocks.
 */
static int
blk_freemask(ufs2_daddr_t blk, ino_t ino, ufs_lbn_t lbn, int frags)
{
        struct suj_blk *sblk;
        struct suj_rec *srec;
        struct jblkrec *brec;
        int mask;
        int off;

        /*
         * To be certain we're not freeing a reallocated block we lookup
         * this block in the blk hash and see if there is an allocation
         * journal record that overlaps with any fragments in the block
         * we're concerned with.  If any fragments have ben reallocated
         * the block has already been freed and re-used for another purpose.
         */
        mask = 0;
        sblk = blk_lookup(blknum(fs, blk), 0);
        if (sblk == NULL)
                return (0);
        off = blk - sblk->sb_blk;
        TAILQ_FOREACH(srec, &sblk->sb_recs, sr_next) {
                brec = (struct jblkrec *)srec->sr_rec;
                /*
                 * If the block overlaps but does not match
                 * exactly this record refers to the current
                 * location.
                 */
                if (blk_overlaps(brec, blk, frags) == 0)
                        continue;
                if (blk_equals(brec, ino, lbn, blk, frags) == 1)
                        mask = 0;
                else
                        blk_setmask(brec, &mask);
        }
        if (debug)
                printf("blk_freemask: blk %jd sblk %jd off %d mask 0x%X\n",
                    blk, sblk->sb_blk, off, mask);
        return (mask >> off);
}

/*
 * Determine whether it is safe to follow an indirect.  It is not safe
 * if any part of the indirect has been reallocated or the last journal
 * entry was an allocation.  Just allocated indirects may not have valid
 * pointers yet and all of their children will have their own records.
 * It is also not safe to follow an indirect if the cg bitmap has been
 * cleared as a new allocation may write to the block prior to the journal
 * being written.
 *
 * Returns 1 if it's safe to follow the indirect and 0 otherwise.
 */
static int
blk_isindir(ufs2_daddr_t blk, ino_t ino, ufs_lbn_t lbn)
{
        struct suj_blk *sblk;
        struct jblkrec *brec;

        sblk = blk_lookup(blk, 0);
        if (sblk == NULL)
                return (1);
        if (TAILQ_EMPTY(&sblk->sb_recs))
                return (1);
        brec = (struct jblkrec *)TAILQ_LAST(&sblk->sb_recs, srechd)->sr_rec;
        if (blk_equals(brec, ino, lbn, blk, fs->fs_frag))
                if (brec->jb_op == JOP_FREEBLK)
                        return (!blk_isfree(blk));
        return (0);
}

/*
 * Clear an inode from the cg bitmap.  If the inode was already clear return
 * 0 so the caller knows it does not have to check the inode contents.
 */
static int
ino_free(ino_t ino, int mode)
{
        struct suj_cg *sc;
        uint8_t *inosused;
        struct cg *cgp;
        int cg;

        cg = ino_to_cg(fs, ino);
        ino = ino % fs->fs_ipg;
        sc = cg_lookup(cg);
        cgp = sc->sc_cgp;
        inosused = cg_inosused(cgp);
        /*
         * The bitmap may never have made it to the disk so we have to
         * conditionally clear.  We can avoid writing the cg in this case.
         */
        if (isclr(inosused, ino))
                return (0);
        freeinos++;
        clrbit(inosused, ino);
        if (ino < cgp->cg_irotor)
                cgp->cg_irotor = ino;
        cgp->cg_cs.cs_nifree++;
        if ((mode & IFMT) == IFDIR) {
                freedir++;
                cgp->cg_cs.cs_ndir--;
        }
        cgdirty(sc->sc_cgbp);

        return (1);
}

/*
 * Free 'frags' frags starting at filesystem block 'bno' skipping any frags
 * set in the mask.
 */
static void
blk_free(ufs2_daddr_t bno, int mask, int frags)
{
        ufs1_daddr_t fragno, cgbno;
        struct suj_cg *sc;
        struct cg *cgp;
        int i, cg;
        uint8_t *blksfree;

        if (debug)
                printf("Freeing %d frags at blk %jd mask 0x%x\n",
                    frags, bno, mask);
        cg = dtog(fs, bno);
        sc = cg_lookup(cg);
        cgp = sc->sc_cgp;
        cgbno = dtogd(fs, bno);
        blksfree = cg_blksfree(cgp);

        /*
         * If it's not allocated we only wrote the journal entry
         * and never the bitmaps.  Here we unconditionally clear and
         * resolve the cg summary later.
         */
        if (frags == fs->fs_frag && mask == 0) {
                fragno = fragstoblks(fs, cgbno);
                ffs_setblock(fs, blksfree, fragno);
                freeblocks++;
        } else {
                /*
                 * deallocate the fragment
                 */
                for (i = 0; i < frags; i++)
                        if ((mask & (1 << i)) == 0 && isclr(blksfree, cgbno +i)) {
                                freefrags++;
                                setbit(blksfree, cgbno + i);
                        }
        }
        cgdirty(sc->sc_cgbp);
}

/*
 * Returns 1 if the whole block starting at 'bno' is marked free and 0
 * otherwise.
 */
static int
blk_isfree(ufs2_daddr_t bno)
{
        struct suj_cg *sc;

        sc = cg_lookup(dtog(fs, bno));
        return ffs_isblock(fs, cg_blksfree(sc->sc_cgp), dtogd(fs, bno));
}

/*
 * Determine whether a block exists at a particular lbn in an inode.
 * Returns 1 if found, 0 if not.  lbn may be negative for indirects
 * or ext blocks.
 */
static int
blk_isat(ino_t ino, ufs_lbn_t lbn, ufs2_daddr_t blk, int *frags)
{
        struct inode ip;
        union dinode *dp;
        ufs2_daddr_t nblk;

        ginode(ino, &ip);
        dp = ip.i_dp;
        if (DIP(dp, di_nlink) == 0 || DIP(dp, di_mode) == 0) {
                irelse(&ip);
                return (0);
        }
        nblk = ino_blkatoff(dp, ino, lbn, frags, NULL);
        irelse(&ip);
        return (nblk == blk);
}

/*
 * Clear the directory entry at diroff that should point to child.  Minimal
 * checking is done and it is assumed that this path was verified with isat.
 */
static void
ino_clrat(ino_t parent, off_t diroff, ino_t child)
{
        union dinode *dip;
        struct direct *dp;
        struct inode ip;
        ufs2_daddr_t blk;
        struct bufarea *bp;
        ufs_lbn_t lbn;
        int blksize;
        int frags;
        int doff;

        if (debug)
                printf("Clearing inode %ju from parent %ju at offset %jd\n",
                    (uintmax_t)child, (uintmax_t)parent, diroff);

        lbn = lblkno(fs, diroff);
        doff = blkoff(fs, diroff);
        ginode(parent, &ip);
        dip = ip.i_dp;
        blk = ino_blkatoff(dip, parent, lbn, &frags, NULL);
        blksize = sblksize(fs, DIP(dip, di_size), lbn);
        irelse(&ip);
        bp = getdatablk(blk, blksize, BT_DIRDATA);
        if (bp->b_errs != 0)
                err_suj("ino_clrat: UNRECOVERABLE I/O ERROR");
        dp = (struct direct *)&bp->b_un.b_buf[doff];
        if (dp->d_ino != child)
                errx(1, "Inode %ju does not exist in %ju at %jd",
                    (uintmax_t)child, (uintmax_t)parent, diroff);
        dp->d_ino = 0;
        dirty(bp);
        brelse(bp);
        /*
         * The actual .. reference count will already have been removed
         * from the parent by the .. remref record.
         */
}

/*
 * Determines whether a pointer to an inode exists within a directory
 * at a specified offset.  Returns the mode of the found entry.
 */
static int
ino_isat(ino_t parent, off_t diroff, ino_t child, int *mode, int *isdot)
{
        struct inode ip;
        union dinode *dip;
        struct bufarea *bp;
        struct direct *dp;
        ufs2_daddr_t blk;
        ufs_lbn_t lbn;
        int blksize;
        int frags;
        int dpoff;
        int doff;

        *isdot = 0;
        ginode(parent, &ip);
        dip = ip.i_dp;
        *mode = DIP(dip, di_mode);
        if ((*mode & IFMT) != IFDIR) {
                if (debug) {
                        /*
                         * This can happen if the parent inode
                         * was reallocated.
                         */
                        if (*mode != 0)
                                printf("Directory %ju has bad mode %o\n",
                                    (uintmax_t)parent, *mode);
                        else
                                printf("Directory %ju has zero mode\n",
                                    (uintmax_t)parent);
                }
                irelse(&ip);
                return (0);
        }
        lbn = lblkno(fs, diroff);
        doff = blkoff(fs, diroff);
        blksize = sblksize(fs, DIP(dip, di_size), lbn);
        if (diroff + DIRECTSIZ(1) > DIP(dip, di_size) || doff >= blksize) {
                if (debug)
                        printf("ino %ju absent from %ju due to offset %jd"
                            " exceeding size %jd\n",
                            (uintmax_t)child, (uintmax_t)parent, diroff,
                            DIP(dip, di_size));
                irelse(&ip);
                return (0);
        }
        blk = ino_blkatoff(dip, parent, lbn, &frags, NULL);
        irelse(&ip);
        if (blk <= 0) {
                if (debug)
                        printf("Sparse directory %ju", (uintmax_t)parent);
                return (0);
        }
        bp = getdatablk(blk, blksize, BT_DIRDATA);
        if (bp->b_errs != 0)
                err_suj("ino_isat: UNRECOVERABLE I/O ERROR");
        /*
         * Walk through the records from the start of the block to be
         * certain we hit a valid record and not some junk in the middle
         * of a file name.  Stop when we reach or pass the expected offset.
         */
        dpoff = rounddown(doff, DIRBLKSIZ);
        do {
                dp = (struct direct *)&bp->b_un.b_buf[dpoff];
                if (dpoff == doff)
                        break;
                if (dp->d_reclen == 0)
                        break;
                dpoff += dp->d_reclen;
        } while (dpoff <= doff);
        if (dpoff > fs->fs_bsize)
                err_suj("Corrupt directory block in dir ino %ju\n",
                    (uintmax_t)parent);
        /* Not found. */
        if (dpoff != doff) {
                if (debug)
                        printf("ino %ju not found in %ju, lbn %jd, dpoff %d\n",
                            (uintmax_t)child, (uintmax_t)parent, lbn, dpoff);
                brelse(bp);
                return (0);
        }
        /*
         * We found the item in question.  Record the mode and whether it's
         * a . or .. link for the caller.
         */
        if (dp->d_ino == child) {
                if (child == parent)
                        *isdot = 1;
                else if (dp->d_namlen == 2 &&
                    dp->d_name[0] == '.' && dp->d_name[1] == '.')
                        *isdot = 1;
                *mode = DTTOIF(dp->d_type);
                brelse(bp);
                return (1);
        }
        if (debug)
                printf("ino %ju doesn't match dirent ino %ju in parent %ju\n",
                    (uintmax_t)child, (uintmax_t)dp->d_ino, (uintmax_t)parent);
        brelse(bp);
        return (0);
}

#define VISIT_INDIR     0x0001
#define VISIT_EXT       0x0002
#define VISIT_ROOT      0x0004  /* Operation came via root & valid pointers. */

/*
 * Read an indirect level which may or may not be linked into an inode.
 */
static void
indir_visit(ino_t ino, ufs_lbn_t lbn, ufs2_daddr_t blk, uint64_t *frags,
    ino_visitor visitor, int flags)
{
        struct bufarea *bp;
        ufs_lbn_t lbnadd;
        ufs2_daddr_t nblk;
        ufs_lbn_t nlbn;
        int level;
        int i;

        /*
         * Don't visit indirect blocks with contents we can't trust.  This
         * should only happen when indir_visit() is called to complete a
         * truncate that never finished and not when a pointer is found via
         * an inode.
         */
        if (blk == 0)
                return;
        level = lbn_level(lbn);
        if (level == -1)
                err_suj("Invalid level for lbn %jd\n", lbn);
        if ((flags & VISIT_ROOT) == 0 && blk_isindir(blk, ino, lbn) == 0) {
                if (debug)
                        printf("blk %jd ino %ju lbn %jd(%d) is not indir.\n",
                            blk, (uintmax_t)ino, lbn, level);
                goto out;
        }
        lbnadd = 1;
        for (i = level; i > 0; i--)
                lbnadd *= NINDIR(fs);
        bp = getdatablk(blk, fs->fs_bsize, BT_LEVEL1 + level);
        if (bp->b_errs != 0)
                err_suj("indir_visit: UNRECOVERABLE I/O ERROR");
        for (i = 0; i < NINDIR(fs); i++) {
                if ((nblk = IBLK(bp, i)) == 0)
                        continue;
                if (level == 0) {
                        nlbn = -lbn + i * lbnadd;
                        (*frags) += fs->fs_frag;
                        visitor(ino, nlbn, nblk, fs->fs_frag);
                } else {
                        nlbn = (lbn + 1) - (i * lbnadd);
                        indir_visit(ino, nlbn, nblk, frags, visitor, flags);
                }
        }
        brelse(bp);
out:
        if (flags & VISIT_INDIR) {
                (*frags) += fs->fs_frag;
                visitor(ino, lbn, blk, fs->fs_frag);
        }
}

/*
 * Visit each block in an inode as specified by 'flags' and call a
 * callback function.  The callback may inspect or free blocks.  The
 * count of frags found according to the size in the file is returned.
 * This is not valid for sparse files but may be used to determine
 * the correct di_blocks for a file.
 */
static uint64_t
ino_visit(union dinode *dp, ino_t ino, ino_visitor visitor, int flags)
{
        ufs_lbn_t nextlbn;
        ufs_lbn_t tmpval;
        ufs_lbn_t lbn;
        uint64_t size;
        uint64_t fragcnt;
        int mode;
        int frags;
        int i;

        size = DIP(dp, di_size);
        mode = DIP(dp, di_mode) & IFMT;
        fragcnt = 0;
        if ((flags & VISIT_EXT) &&
            fs->fs_magic == FS_UFS2_MAGIC && dp->dp2.di_extsize) {
                for (i = 0; i < UFS_NXADDR; i++) {
                        if (dp->dp2.di_extb[i] == 0)
                                continue;
                        frags = sblksize(fs, dp->dp2.di_extsize, i);
                        frags = numfrags(fs, frags);
                        fragcnt += frags;
                        visitor(ino, -1 - i, dp->dp2.di_extb[i], frags);
                }
        }
        /* Skip datablocks for short links and devices. */
        if (mode == IFBLK || mode == IFCHR ||
            (mode == IFLNK && size < fs->fs_maxsymlinklen))
                return (fragcnt);
        for (i = 0; i < UFS_NDADDR; i++) {
                if (DIP(dp, di_db[i]) == 0)
                        continue;
                frags = sblksize(fs, size, i);
                frags = numfrags(fs, frags);
                fragcnt += frags;
                visitor(ino, i, DIP(dp, di_db[i]), frags);
        }
        /*
         * We know the following indirects are real as we're following
         * real pointers to them.
         */
        flags |= VISIT_ROOT;
        for (i = 0, tmpval = NINDIR(fs), lbn = UFS_NDADDR; i < UFS_NIADDR; i++,
            lbn = nextlbn) {
                nextlbn = lbn + tmpval;
                tmpval *= NINDIR(fs);
                if (DIP(dp, di_ib[i]) == 0)
                        continue;
                indir_visit(ino, -lbn - i, DIP(dp, di_ib[i]), &fragcnt, visitor,
                    flags);
        }
        return (fragcnt);
}

/*
 * Null visitor function used when we just want to count blocks and
 * record the lbn.
 */
ufs_lbn_t visitlbn;
static void
null_visit(ino_t ino, ufs_lbn_t lbn, ufs2_daddr_t blk, int frags)
{
        if (lbn > 0)
                visitlbn = lbn;
}

/*
 * Recalculate di_blocks when we discover that a block allocation or
 * free was not successfully completed.  The kernel does not roll this back
 * because it would be too expensive to compute which indirects were
 * reachable at the time the inode was written.
 */
static void
ino_adjblks(struct suj_ino *sino)
{
        struct inode ip;
        union dinode *dp;
        uint64_t blocks;
        uint64_t frags;
        off_t isize;
        off_t size;
        ino_t ino;

        ino = sino->si_ino;
        ginode(ino, &ip);
        dp = ip.i_dp;
        /* No need to adjust zero'd inodes. */
        if (DIP(dp, di_mode) == 0) {
                irelse(&ip);
                return;
        }
        /*
         * Visit all blocks and count them as well as recording the last
         * valid lbn in the file.  If the file size doesn't agree with the
         * last lbn we need to truncate to fix it.  Otherwise just adjust
         * the blocks count.
         */
        visitlbn = 0;
        frags = ino_visit(dp, ino, null_visit, VISIT_INDIR | VISIT_EXT);
        blocks = fsbtodb(fs, frags);
        /*
         * We assume the size and direct block list is kept coherent by
         * softdep.  For files that have extended into indirects we truncate
         * to the size in the inode or the maximum size permitted by
         * populated indirects.
         */
        if (visitlbn >= UFS_NDADDR) {
                isize = DIP(dp, di_size);
                size = lblktosize(fs, visitlbn + 1);
                if (isize > size)
                        isize = size;
                /* Always truncate to free any unpopulated indirects. */
                ino_trunc(ino, isize);
                irelse(&ip);
                return;
        }
        if (blocks == DIP(dp, di_blocks)) {
                irelse(&ip);
                return;
        }
        if (debug)
                printf("ino %ju adjusting block count from %jd to %jd\n",
                    (uintmax_t)ino, DIP(dp, di_blocks), blocks);
        DIP_SET(dp, di_blocks, blocks);
        inodirty(&ip);
        irelse(&ip);
}

static void
blk_free_visit(ino_t ino, ufs_lbn_t lbn, ufs2_daddr_t blk, int frags)
{

        blk_free(blk, blk_freemask(blk, ino, lbn, frags), frags);
}

/*
 * Free a block or tree of blocks that was previously rooted in ino at
 * the given lbn.  If the lbn is an indirect all children are freed
 * recursively.
 */
static void
blk_free_lbn(ufs2_daddr_t blk, ino_t ino, ufs_lbn_t lbn, int frags, int follow)
{
        uint64_t resid;
        int mask;

        mask = blk_freemask(blk, ino, lbn, frags);
        resid = 0;
        if (lbn <= -UFS_NDADDR && follow && mask == 0)
                indir_visit(ino, lbn, blk, &resid, blk_free_visit, VISIT_INDIR);
        else
                blk_free(blk, mask, frags);
}

static void
ino_setskip(struct suj_ino *sino, ino_t parent)
{
        int isdot;
        int mode;

        if (ino_isat(sino->si_ino, DOTDOT_OFFSET, parent, &mode, &isdot))
                sino->si_skipparent = 1;
}

static void
ino_remref(ino_t parent, ino_t child, uint64_t diroff, int isdotdot)
{
        struct suj_ino *sino;
        struct suj_rec *srec;
        struct jrefrec *rrec;

        /*
         * Lookup this inode to see if we have a record for it.
         */
        sino = ino_lookup(child, 0);
        /*
         * Tell any child directories we've already removed their
         * parent link cnt.  Don't try to adjust our link down again.
         */
        if (sino != NULL && isdotdot == 0)
                ino_setskip(sino, parent);
        /*
         * No valid record for this inode.  Just drop the on-disk
         * link by one.
         */
        if (sino == NULL || sino->si_hasrecs == 0) {
                ino_decr(child);
                return;
        }
        /*
         * Use ino_adjust() if ino_check() has already processed this
         * child.  If we lose the last non-dot reference to a
         * directory it will be discarded.
         */
        if (sino->si_linkadj) {
                if (sino->si_nlink == 0)
                        err_suj("ino_remref: ino %ld mode 0%o about to go "
                            "negative\n", sino->si_ino, sino->si_mode);
                sino->si_nlink--;
                if (isdotdot)
                        sino->si_dotlinks--;
                ino_adjust(sino);
                return;
        }
        /*
         * If we haven't yet processed this inode we need to make
         * sure we will successfully discover the lost path.  If not
         * use nlinkadj to remember.
         */
        TAILQ_FOREACH(srec, &sino->si_recs, sr_next) {
                rrec = (struct jrefrec *)srec->sr_rec;
                if (rrec->jr_parent == parent &&
                    rrec->jr_diroff == diroff)
                        return;
        }
        sino->si_nlinkadj++;
}

/*
 * Free the children of a directory when the directory is discarded.
 */
static void
ino_free_children(ino_t ino, ufs_lbn_t lbn, ufs2_daddr_t blk, int frags)
{
        struct suj_ino *sino;
        struct bufarea *bp;
        struct direct *dp;
        off_t diroff;
        int skipparent;
        int isdotdot;
        int dpoff;
        int size;

        sino = ino_lookup(ino, 0);
        if (sino)
                skipparent = sino->si_skipparent;
        else
                skipparent = 0;
        size = lfragtosize(fs, frags);
        bp = getdatablk(blk, size, BT_DIRDATA);
        if (bp->b_errs != 0)
                err_suj("ino_free_children: UNRECOVERABLE I/O ERROR");
        dp = (struct direct *)&bp->b_un.b_buf[0];
        for (dpoff = 0; dpoff < size && dp->d_reclen; dpoff += dp->d_reclen) {
                dp = (struct direct *)&bp->b_un.b_buf[dpoff];
                if (dp->d_ino == 0 || dp->d_ino == UFS_WINO)
                        continue;
                if (dp->d_namlen == 1 && dp->d_name[0] == '.')
                        continue;
                isdotdot = dp->d_namlen == 2 && dp->d_name[0] == '.' &&
                    dp->d_name[1] == '.';
                if (isdotdot && skipparent == 1)
                        continue;
                if (debug)
                        printf("Directory %ju removing ino %ju name %s\n",
                            (uintmax_t)ino, (uintmax_t)dp->d_ino, dp->d_name);
                diroff = lblktosize(fs, lbn) + dpoff;
                ino_remref(ino, dp->d_ino, diroff, isdotdot);
        }
        brelse(bp);
}

/*
 * Reclaim an inode, freeing all blocks and decrementing all children's
 * link counts.  Free the inode back to the cg.
 */
static void
ino_reclaim(struct inode *ip, ino_t ino, int mode)
{
        union dinode *dp;
        uint32_t gen;

        dp = ip->i_dp;
        if (ino == UFS_ROOTINO)
                err_suj("Attempting to free UFS_ROOTINO\n");
        if (debug)
                printf("Truncating and freeing ino %ju, nlink %d, mode %o\n",
                    (uintmax_t)ino, DIP(dp, di_nlink), DIP(dp, di_mode));

        /* We are freeing an inode or directory. */
        if ((DIP(dp, di_mode) & IFMT) == IFDIR)
                ino_visit(dp, ino, ino_free_children, 0);
        DIP_SET(dp, di_nlink, 0);
        ino_visit(dp, ino, blk_free_visit, VISIT_EXT | VISIT_INDIR);
        /* Here we have to clear the inode and release any blocks it holds. */
        gen = DIP(dp, di_gen);
        if (fs->fs_magic == FS_UFS1_MAGIC)
                bzero(dp, sizeof(struct ufs1_dinode));
        else
                bzero(dp, sizeof(struct ufs2_dinode));
        DIP_SET(dp, di_gen, gen);
        inodirty(ip);
        ino_free(ino, mode);
        return;
}

/*
 * Adjust an inode's link count down by one when a directory goes away.
 */
static void
ino_decr(ino_t ino)
{
        struct inode ip;
        union dinode *dp;
        int reqlink;
        int nlink;
        int mode;

        ginode(ino, &ip);
        dp = ip.i_dp;
        nlink = DIP(dp, di_nlink);
        mode = DIP(dp, di_mode);
        if (nlink < 1)
                err_suj("Inode %d link count %d invalid\n", ino, nlink);
        if (mode == 0)
                err_suj("Inode %d has a link of %d with 0 mode\n", ino, nlink);
        nlink--;
        if ((mode & IFMT) == IFDIR)
                reqlink = 2;
        else
                reqlink = 1;
        if (nlink < reqlink) {
                if (debug)
                        printf("ino %ju not enough links to live %d < %d\n",
                            (uintmax_t)ino, nlink, reqlink);
                ino_reclaim(&ip, ino, mode);
                irelse(&ip);
                return;
        }
        DIP_SET(dp, di_nlink, nlink);
        inodirty(&ip);
        irelse(&ip);
}

/*
 * Adjust the inode link count to 'nlink'.  If the count reaches zero
 * free it.
 */
static void
ino_adjust(struct suj_ino *sino)
{
        struct jrefrec *rrec;
        struct suj_rec *srec;
        struct suj_ino *stmp;
        union dinode *dp;
        struct inode ip;
        nlink_t nlink;
        nlink_t reqlink;
        int recmode;
        int isdot;
        int mode;
        ino_t ino;

        nlink = sino->si_nlink;
        ino = sino->si_ino;
        mode = sino->si_mode & IFMT;
        /*
         * If it's a directory with no dot links, it was truncated before
         * the name was cleared.  We need to clear the dirent that
         * points at it.
         */
        if (mode == IFDIR && nlink == 1 && sino->si_dotlinks == 0) {
                sino->si_nlink = nlink = 0;
                TAILQ_FOREACH(srec, &sino->si_recs, sr_next) {
                        rrec = (struct jrefrec *)srec->sr_rec;
                        if (ino_isat(rrec->jr_parent, rrec->jr_diroff, ino,
                            &recmode, &isdot) == 0)
                                continue;
                        ino_clrat(rrec->jr_parent, rrec->jr_diroff, ino);
                        break;
                }
                if (srec == NULL)
                        errx(1, "Directory %ju name not found", (uintmax_t)ino);
        }
        /*
         * If it's a directory with no real names pointing to it go ahead
         * and truncate it.  This will free any children.
         */
        if (mode == IFDIR && nlink - sino->si_dotlinks == 0) {
                sino->si_nlink = nlink = 0;
                /*
                 * Mark any .. links so they know not to free this inode
                 * when they are removed.
                 */
                TAILQ_FOREACH(srec, &sino->si_recs, sr_next) {
                        rrec = (struct jrefrec *)srec->sr_rec;
                        if (rrec->jr_diroff == DOTDOT_OFFSET) {
                                stmp = ino_lookup(rrec->jr_parent, 0);
                                if (stmp)
                                        ino_setskip(stmp, ino);
                        }
                }
        }
        ginode(ino, &ip);
        dp = ip.i_dp;
        mode = DIP(dp, di_mode) & IFMT;
        if (nlink > UFS_LINK_MAX)
                err_suj("ino %ju nlink manipulation error, new %ju, old %d\n",
                    (uintmax_t)ino, (uintmax_t)nlink, DIP(dp, di_nlink));
        if (debug)
               printf("Adjusting ino %ju, nlink %ju, old link %d lastmode %o\n",
                    (uintmax_t)ino, (uintmax_t)nlink, DIP(dp, di_nlink),
                    sino->si_mode);
        if (mode == 0) {
                if (debug)
                        printf("ino %ju, zero inode freeing bitmap\n",
                            (uintmax_t)ino);
                ino_free(ino, sino->si_mode);
                irelse(&ip);
                return;
        }
        /* XXX Should be an assert? */
        if (mode != sino->si_mode && debug)
                printf("ino %ju, mode %o != %o\n",
                    (uintmax_t)ino, mode, sino->si_mode);
        if ((mode & IFMT) == IFDIR)
                reqlink = 2;
        else
                reqlink = 1;
        /* If the inode doesn't have enough links to live, free it. */
        if (nlink < reqlink) {
                if (debug)
                        printf("ino %ju not enough links to live %ju < %ju\n",
                            (uintmax_t)ino, (uintmax_t)nlink,
                            (uintmax_t)reqlink);
                ino_reclaim(&ip, ino, mode);
                irelse(&ip);
                return;
        }
        /* If required write the updated link count. */
        if (DIP(dp, di_nlink) == nlink) {
                if (debug)
                        printf("ino %ju, link matches, skipping.\n",
                            (uintmax_t)ino);
                irelse(&ip);
                return;
        }
        DIP_SET(dp, di_nlink, nlink);
        inodirty(&ip);
        irelse(&ip);
}

/*
 * Truncate some or all blocks in an indirect, freeing any that are required
 * and zeroing the indirect.
 */
static void
indir_trunc(ino_t ino, ufs_lbn_t lbn, ufs2_daddr_t blk, ufs_lbn_t lastlbn,
        union dinode *dp)
{
        struct bufarea *bp;
        ufs_lbn_t lbnadd;
        ufs2_daddr_t nblk;
        ufs_lbn_t next;
        ufs_lbn_t nlbn;
        int isdirty;
        int level;
        int i;

        if (blk == 0)
                return;
        isdirty = 0;
        level = lbn_level(lbn);
        if (level == -1)
                err_suj("Invalid level for lbn %jd\n", lbn);
        lbnadd = 1;
        for (i = level; i > 0; i--)
                lbnadd *= NINDIR(fs);
        bp = getdatablk(blk, fs->fs_bsize, BT_LEVEL1 + level);
        if (bp->b_errs != 0)
                err_suj("indir_trunc: UNRECOVERABLE I/O ERROR");
        for (i = 0; i < NINDIR(fs); i++) {
                if ((nblk = IBLK(bp, i)) == 0)
                        continue;
                if (level != 0) {
                        nlbn = (lbn + 1) - (i * lbnadd);
                        /*
                         * Calculate the lbn of the next indirect to
                         * determine if any of this indirect must be
                         * reclaimed.
                         */
                        next = -(lbn + level) + ((i+1) * lbnadd);
                        if (next <= lastlbn)
                                continue;
                        indir_trunc(ino, nlbn, nblk, lastlbn, dp);
                        /* If all of this indirect was reclaimed, free it. */
                        nlbn = next - lbnadd;
                        if (nlbn < lastlbn)
                                continue;
                } else {
                        nlbn = -lbn + i * lbnadd;
                        if (nlbn < lastlbn)
                                continue;
                }
                isdirty = 1;
                blk_free(nblk, 0, fs->fs_frag);
                IBLK_SET(bp, i, 0);
        }
        if (isdirty)
                dirty(bp);
        brelse(bp);
}

/*
 * Truncate an inode to the minimum of the given size or the last populated
 * block after any over size have been discarded.  The kernel would allocate
 * the last block in the file but fsck does not and neither do we.  This
 * code never extends files, only shrinks them.
 */
static void
ino_trunc(ino_t ino, off_t size)
{
        struct inode ip;
        union dinode *dp;
        struct bufarea *bp;
        ufs2_daddr_t bn;
        uint64_t totalfrags;
        ufs_lbn_t nextlbn;
        ufs_lbn_t lastlbn;
        ufs_lbn_t tmpval;
        ufs_lbn_t lbn;
        ufs_lbn_t i;
        int blksize, frags;
        off_t cursize;
        off_t off;
        int mode;

        ginode(ino, &ip);
        dp = ip.i_dp;
        mode = DIP(dp, di_mode) & IFMT;
        cursize = DIP(dp, di_size);
        if (debug)
                printf("Truncating ino %ju, mode %o to size %jd from size %jd\n",
                    (uintmax_t)ino, mode, size, cursize);

        /* Skip datablocks for short links and devices. */
        if (mode == 0 || mode == IFBLK || mode == IFCHR ||
            (mode == IFLNK && cursize < fs->fs_maxsymlinklen)) {
                irelse(&ip);
                return;
        }
        /* Don't extend. */
        if (size > cursize) {
                irelse(&ip);
                return;
        }
        if ((DIP(dp, di_flags) & SF_SNAPSHOT) != 0) {
                if (size > 0)
                        err_suj("Partial truncation of ino %ju snapshot file\n",
                            (uintmax_t)ino);
        }
        lastlbn = lblkno(fs, blkroundup(fs, size));
        for (i = lastlbn; i < UFS_NDADDR; i++) {
                if ((bn = DIP(dp, di_db[i])) == 0)
                        continue;
                blksize = sblksize(fs, cursize, i);
                blk_free(bn, 0, numfrags(fs, blksize));
                DIP_SET(dp, di_db[i], 0);
        }
        /*
         * Follow indirect blocks, freeing anything required.
         */
        for (i = 0, tmpval = NINDIR(fs), lbn = UFS_NDADDR; i < UFS_NIADDR; i++,
            lbn = nextlbn) {
                nextlbn = lbn + tmpval;
                tmpval *= NINDIR(fs);
                /* If we're not freeing any in this indirect range skip it. */
                if (lastlbn >= nextlbn)
                        continue;
                if (DIP(dp, di_ib[i]) == 0)
                        continue;
                indir_trunc(ino, -lbn - i, DIP(dp, di_ib[i]), lastlbn, dp);
                /* If we freed everything in this indirect free the indir. */
                if (lastlbn > lbn)
                        continue;
                blk_free(DIP(dp, di_ib[i]), 0, fs->fs_frag);
                DIP_SET(dp, di_ib[i], 0);
        }
        /*
         * Now that we've freed any whole blocks that exceed the desired
         * truncation size, figure out how many blocks remain and what the
         * last populated lbn is.  We will set the size to this last lbn
         * rather than worrying about allocating the final lbn as the kernel
         * would've done.  This is consistent with normal fsck behavior.
         */
        visitlbn = 0;
        totalfrags = ino_visit(dp, ino, null_visit, VISIT_INDIR | VISIT_EXT);
        if (size > lblktosize(fs, visitlbn + 1))
                size = lblktosize(fs, visitlbn + 1);
        /*
         * If we're truncating direct blocks we have to adjust frags
         * accordingly.
         */
        if (visitlbn < UFS_NDADDR && totalfrags) {
                long oldspace, newspace;

                bn = DIP(dp, di_db[visitlbn]);
                if (bn == 0)
                        err_suj("Bad blk at ino %ju lbn %jd\n",
                            (uintmax_t)ino, visitlbn);
                oldspace = sblksize(fs, cursize, visitlbn);
                newspace = sblksize(fs, size, visitlbn);
                if (oldspace != newspace) {
                        bn += numfrags(fs, newspace);
                        frags = numfrags(fs, oldspace - newspace);
                        blk_free(bn, 0, frags);
                        totalfrags -= frags;
                }
        }
        DIP_SET(dp, di_blocks, fsbtodb(fs, totalfrags));
        DIP_SET(dp, di_size, size);
        inodirty(&ip);
        /*
         * If we've truncated into the middle of a block or frag we have
         * to zero it here.  Otherwise the file could extend into
         * uninitialized space later.
         */
        off = blkoff(fs, size);
        if (off && DIP(dp, di_mode) != IFDIR) {
                long clrsize;

                bn = ino_blkatoff(dp, ino, visitlbn, &frags, NULL);
                if (bn == 0)
                        err_suj("Block missing from ino %ju at lbn %jd\n",
                            (uintmax_t)ino, visitlbn);
                clrsize = frags * fs->fs_fsize;
                bp = getdatablk(bn, clrsize, BT_DATA);
                if (bp->b_errs != 0)
                        err_suj("ino_trunc: UNRECOVERABLE I/O ERROR");
                clrsize -= off;
                bzero(&bp->b_un.b_buf[off], clrsize);
                dirty(bp);
                brelse(bp);
        }
        irelse(&ip);
        return;
}

/*
 * Process records available for one inode and determine whether the
 * link count is correct or needs adjusting.
 */
static void
ino_check(struct suj_ino *sino)
{
        struct suj_rec *srec;
        struct jrefrec *rrec;
        nlink_t dotlinks;
        nlink_t newlinks;
        nlink_t removes;
        nlink_t nlink;
        ino_t ino;
        int isdot;
        int isat;
        int mode;

        if (sino->si_hasrecs == 0)
                return;
        ino = sino->si_ino;
        rrec = (struct jrefrec *)TAILQ_FIRST(&sino->si_recs)->sr_rec;
        nlink = rrec->jr_nlink;
        newlinks = 0;
        dotlinks = 0;
        removes = sino->si_nlinkadj;
        TAILQ_FOREACH(srec, &sino->si_recs, sr_next) {
                rrec = (struct jrefrec *)srec->sr_rec;
                isat = ino_isat(rrec->jr_parent, rrec->jr_diroff,
                    rrec->jr_ino, &mode, &isdot);
                if (isat && (mode & IFMT) != (rrec->jr_mode & IFMT))
                        err_suj("Inode mode/directory type mismatch %o != %o\n",
                            mode, rrec->jr_mode);
                if (debug)
                        printf("jrefrec: op %d ino %ju, nlink %ju, parent %ju, "
                            "diroff %jd, mode %o, isat %d, isdot %d\n",
                            rrec->jr_op, (uintmax_t)rrec->jr_ino,
                            (uintmax_t)rrec->jr_nlink,
                            (uintmax_t)rrec->jr_parent,
                            (uintmax_t)rrec->jr_diroff,
                            rrec->jr_mode, isat, isdot);
                mode = rrec->jr_mode & IFMT;
                if (rrec->jr_op == JOP_REMREF)
                        removes++;
                newlinks += isat;
                if (isdot)
                        dotlinks += isat;
        }
        /*
         * The number of links that remain are the starting link count
         * subtracted by the total number of removes with the total
         * links discovered back in.  An incomplete remove thus
         * makes no change to the link count but an add increases
         * by one.
         */
        if (debug)
                printf(
                    "ino %ju nlink %ju newlinks %ju removes %ju dotlinks %ju\n",
                    (uintmax_t)ino, (uintmax_t)nlink, (uintmax_t)newlinks,
                    (uintmax_t)removes, (uintmax_t)dotlinks);
        nlink += newlinks;
        nlink -= removes;
        sino->si_linkadj = 1;
        sino->si_nlink = nlink;
        sino->si_dotlinks = dotlinks;
        sino->si_mode = mode;
        ino_adjust(sino);
}

/*
 * Process records available for one block and determine whether it is
 * still allocated and whether the owning inode needs to be updated or
 * a free completed.
 */
static void
blk_check(struct suj_blk *sblk)
{
        struct suj_rec *srec;
        struct jblkrec *brec;
        struct suj_ino *sino;
        ufs2_daddr_t blk;
        int mask;
        int frags;
        int isat;

        /*
         * Each suj_blk actually contains records for any fragments in that
         * block.  As a result we must evaluate each record individually.
         */
        sino = NULL;
        TAILQ_FOREACH(srec, &sblk->sb_recs, sr_next) {
                brec = (struct jblkrec *)srec->sr_rec;
                frags = brec->jb_frags;
                blk = brec->jb_blkno + brec->jb_oldfrags;
                isat = blk_isat(brec->jb_ino, brec->jb_lbn, blk, &frags);
                if (sino == NULL || sino->si_ino != brec->jb_ino) {
                        sino = ino_lookup(brec->jb_ino, 1);
                        sino->si_blkadj = 1;
                }
                if (debug)
                        printf("op %d blk %jd ino %ju lbn %jd frags %d isat %d (%d)\n",
                            brec->jb_op, blk, (uintmax_t)brec->jb_ino,
                            brec->jb_lbn, brec->jb_frags, isat, frags);
                /*
                 * If we found the block at this address we still have to
                 * determine if we need to free the tail end that was
                 * added by adding contiguous fragments from the same block.
                 */
                if (isat == 1) {
                        if (frags == brec->jb_frags)
                                continue;
                        mask = blk_freemask(blk, brec->jb_ino, brec->jb_lbn,
                            brec->jb_frags);
                        mask >>= frags;
                        blk += frags;
                        frags = brec->jb_frags - frags;
                        blk_free(blk, mask, frags);
                        continue;
                }
                /*
                 * The block wasn't found, attempt to free it.  It won't be
                 * freed if it was actually reallocated.  If this was an
                 * allocation we don't want to follow indirects as they
                 * may not be written yet.  Any children of the indirect will
                 * have their own records.  If it's a free we need to
                 * recursively free children.
                 */
                blk_free_lbn(blk, brec->jb_ino, brec->jb_lbn, brec->jb_frags,
                    brec->jb_op == JOP_FREEBLK);
        }
}

/*
 * Walk the list of inode records for this cg and resolve moved and duplicate
 * inode references now that we have a complete picture.
 */
static void
cg_build(struct suj_cg *sc)
{
        struct suj_ino *sino;
        int i;

        for (i = 0; i < HASHSIZE; i++)
                LIST_FOREACH(sino, &sc->sc_inohash[i], si_next)
                        ino_build(sino);
}

/*
 * Handle inodes requiring truncation.  This must be done prior to
 * looking up any inodes in directories.
 */
static void
cg_trunc(struct suj_cg *sc)
{
        struct suj_ino *sino;
        int i;

        for (i = 0; i < HASHSIZE; i++) {
                LIST_FOREACH(sino, &sc->sc_inohash[i], si_next) {
                        if (sino->si_trunc) {
                                ino_trunc(sino->si_ino,
                                    sino->si_trunc->jt_size);
                                sino->si_blkadj = 0;
                                sino->si_trunc = NULL;
                        }
                        if (sino->si_blkadj)
                                ino_adjblks(sino);
                }
        }
}

static void
cg_adj_blk(struct suj_cg *sc)
{
        struct suj_ino *sino;
        int i;

        for (i = 0; i < HASHSIZE; i++) {
                LIST_FOREACH(sino, &sc->sc_inohash[i], si_next) {
                        if (sino->si_blkadj)
                                ino_adjblks(sino);
                }
        }
}

/*
 * Free any partially allocated blocks and then resolve inode block
 * counts.
 */
static void
cg_check_blk(struct suj_cg *sc)
{
        struct suj_blk *sblk;
        int i;


        for (i = 0; i < HASHSIZE; i++)
                LIST_FOREACH(sblk, &sc->sc_blkhash[i], sb_next)
                        blk_check(sblk);
}

/*
 * Walk the list of inode records for this cg, recovering any
 * changes which were not complete at the time of crash.
 */
static void
cg_check_ino(struct suj_cg *sc)
{
        struct suj_ino *sino;
        int i;

        for (i = 0; i < HASHSIZE; i++)
                LIST_FOREACH(sino, &sc->sc_inohash[i], si_next)
                        ino_check(sino);
}

static void
cg_apply(void (*apply)(struct suj_cg *))
{
        struct suj_cg *scg;
        int i;

        for (i = 0; i < HASHSIZE; i++)
                LIST_FOREACH(scg, &cghash[i], sc_next)
                        apply(scg);
}

/*
 * Process the unlinked but referenced file list.  Freeing all inodes.
 */
static void
ino_unlinked(void)
{
        struct inode ip;
        union dinode *dp;
        uint16_t mode;
        ino_t inon;
        ino_t ino;

        ino = fs->fs_sujfree;
        fs->fs_sujfree = 0;
        while (ino != 0) {
                ginode(ino, &ip);
                dp = ip.i_dp;
                mode = DIP(dp, di_mode) & IFMT;
                inon = DIP(dp, di_freelink);
                DIP_SET(dp, di_freelink, 0);
                inodirty(&ip);
                /*
                 * XXX Should this be an errx?
                 */
                if (DIP(dp, di_nlink) == 0) {
                        if (debug)
                                printf("Freeing unlinked ino %ju mode %o\n",
                                    (uintmax_t)ino, mode);
                        ino_reclaim(&ip, ino, mode);
                } else if (debug)
                        printf("Skipping ino %ju mode %o with link %d\n",
                            (uintmax_t)ino, mode, DIP(dp, di_nlink));
                ino = inon;
                irelse(&ip);
        }
}

/*
 * Append a new record to the list of records requiring processing.
 */
static void
ino_append(union jrec *rec)
{
        struct jrefrec *refrec;
        struct jmvrec *mvrec;
        struct suj_ino *sino;
        struct suj_rec *srec;

        mvrec = &rec->rec_jmvrec;
        refrec = &rec->rec_jrefrec;
        if (debug && mvrec->jm_op == JOP_MVREF)
                printf("ino move: ino %ju, parent %ju, "
                    "diroff %jd, oldoff %jd\n",
                    (uintmax_t)mvrec->jm_ino, (uintmax_t)mvrec->jm_parent,
                    (uintmax_t)mvrec->jm_newoff, (uintmax_t)mvrec->jm_oldoff);
        else if (debug &&
            (refrec->jr_op == JOP_ADDREF || refrec->jr_op == JOP_REMREF))
                printf("ino ref: op %d, ino %ju, nlink %ju, "
                    "parent %ju, diroff %jd\n",
                    refrec->jr_op, (uintmax_t)refrec->jr_ino,
                    (uintmax_t)refrec->jr_nlink,
                    (uintmax_t)refrec->jr_parent, (uintmax_t)refrec->jr_diroff);
        sino = ino_lookup(((struct jrefrec *)rec)->jr_ino, 1);
        sino->si_hasrecs = 1;
        srec = errmalloc(sizeof(*srec));
        srec->sr_rec = rec;
        TAILQ_INSERT_TAIL(&sino->si_newrecs, srec, sr_next);
}

/*
 * Add a reference adjustment to the sino list and eliminate dups.  The
 * primary loop in ino_build_ref() checks for dups but new ones may be
 * created as a result of offset adjustments.
 */
static void
ino_add_ref(struct suj_ino *sino, struct suj_rec *srec)
{
        struct jrefrec *refrec;
        struct suj_rec *srn;
        struct jrefrec *rrn;

        refrec = (struct jrefrec *)srec->sr_rec;
        /*
         * We walk backwards so that the oldest link count is preserved.  If
         * an add record conflicts with a remove keep the remove.  Redundant
         * removes are eliminated in ino_build_ref.  Otherwise we keep the
         * oldest record at a given location.
         */
        for (srn = TAILQ_LAST(&sino->si_recs, srechd); srn;
            srn = TAILQ_PREV(srn, srechd, sr_next)) {
                rrn = (struct jrefrec *)srn->sr_rec;
                if (rrn->jr_parent != refrec->jr_parent ||
                    rrn->jr_diroff != refrec->jr_diroff)
                        continue;
                if (rrn->jr_op == JOP_REMREF || refrec->jr_op == JOP_ADDREF) {
                        rrn->jr_mode = refrec->jr_mode;
                        return;
                }
                /*
                 * Adding a remove.
                 *
                 * Replace the record in place with the old nlink in case
                 * we replace the head of the list.  Abandon srec as a dup.
                 */
                refrec->jr_nlink = rrn->jr_nlink;
                srn->sr_rec = srec->sr_rec;
                return;
        }
        TAILQ_INSERT_TAIL(&sino->si_recs, srec, sr_next);
}

/*
 * Create a duplicate of a reference at a previous location.
 */
static void
ino_dup_ref(struct suj_ino *sino, struct jrefrec *refrec, off_t diroff)
{
        struct jrefrec *rrn;
        struct suj_rec *srn;

        rrn = errmalloc(sizeof(*refrec));
        *rrn = *refrec;
        rrn->jr_op = JOP_ADDREF;
        rrn->jr_diroff = diroff;
        srn = errmalloc(sizeof(*srn));
        srn->sr_rec = (union jrec *)rrn;
        ino_add_ref(sino, srn);
}

/*
 * Add a reference to the list at all known locations.  We follow the offset
 * changes for a single instance and create duplicate add refs at each so
 * that we can tolerate any version of the directory block.  Eliminate
 * removes which collide with adds that are seen in the journal.  They should
 * not adjust the link count down.
 */
static void
ino_build_ref(struct suj_ino *sino, struct suj_rec *srec)
{
        struct jrefrec *refrec;
        struct jmvrec *mvrec;
        struct suj_rec *srp;
        struct suj_rec *srn;
        struct jrefrec *rrn;
        off_t diroff;

        refrec = (struct jrefrec *)srec->sr_rec;
        /*
         * Search for a mvrec that matches this offset.  Whether it's an add
         * or a remove we can delete the mvref after creating a dup record in
         * the old location.
         */
        if (!TAILQ_EMPTY(&sino->si_movs)) {
                diroff = refrec->jr_diroff;
                for (srn = TAILQ_LAST(&sino->si_movs, srechd); srn; srn = srp) {
                        srp = TAILQ_PREV(srn, srechd, sr_next);
                        mvrec = (struct jmvrec *)srn->sr_rec;
                        if (mvrec->jm_parent != refrec->jr_parent ||
                            mvrec->jm_newoff != diroff)
                                continue;
                        diroff = mvrec->jm_oldoff;
                        TAILQ_REMOVE(&sino->si_movs, srn, sr_next);
                        free(srn);
                        ino_dup_ref(sino, refrec, diroff);
                }
        }
        /*
         * If a remove wasn't eliminated by an earlier add just append it to
         * the list.
         */
        if (refrec->jr_op == JOP_REMREF) {
                ino_add_ref(sino, srec);
                return;
        }
        /*
         * Walk the list of records waiting to be added to the list.  We
         * must check for moves that apply to our current offset and remove
         * them from the list.  Remove any duplicates to eliminate removes
         * with corresponding adds.
         */
        TAILQ_FOREACH_SAFE(srn, &sino->si_newrecs, sr_next, srp) {
                switch (srn->sr_rec->rec_jrefrec.jr_op) {
                case JOP_ADDREF:
                        /*
                         * This should actually be an error we should
                         * have a remove for every add journaled.
                         */
                        rrn = (struct jrefrec *)srn->sr_rec;
                        if (rrn->jr_parent != refrec->jr_parent ||
                            rrn->jr_diroff != refrec->jr_diroff)
                                break;
                        TAILQ_REMOVE(&sino->si_newrecs, srn, sr_next);
                        break;
                case JOP_REMREF:
                        /*
                         * Once we remove the current iteration of the
                         * record at this address we're done.
                         */
                        rrn = (struct jrefrec *)srn->sr_rec;
                        if (rrn->jr_parent != refrec->jr_parent ||
                            rrn->jr_diroff != refrec->jr_diroff)
                                break;
                        TAILQ_REMOVE(&sino->si_newrecs, srn, sr_next);
                        ino_add_ref(sino, srec);
                        return;
                case JOP_MVREF:
                        /*
                         * Update our diroff based on any moves that match
                         * and remove the move.
                         */
                        mvrec = (struct jmvrec *)srn->sr_rec;
                        if (mvrec->jm_parent != refrec->jr_parent ||
                            mvrec->jm_oldoff != refrec->jr_diroff)
                                break;
                        ino_dup_ref(sino, refrec, mvrec->jm_oldoff);
                        refrec->jr_diroff = mvrec->jm_newoff;
                        TAILQ_REMOVE(&sino->si_newrecs, srn, sr_next);
                        break;
                default:
                        err_suj("ino_build_ref: Unknown op %d\n",
                            srn->sr_rec->rec_jrefrec.jr_op);
                }
        }
        ino_add_ref(sino, srec);
}

/*
 * Walk the list of new records and add them in-order resolving any
 * dups and adjusted offsets.
 */
static void
ino_build(struct suj_ino *sino)
{
        struct suj_rec *srec;

        while ((srec = TAILQ_FIRST(&sino->si_newrecs)) != NULL) {
                TAILQ_REMOVE(&sino->si_newrecs, srec, sr_next);
                switch (srec->sr_rec->rec_jrefrec.jr_op) {
                case JOP_ADDREF:
                case JOP_REMREF:
                        ino_build_ref(sino, srec);
                        break;
                case JOP_MVREF:
                        /*
                         * Add this mvrec to the queue of pending mvs.
                         */
                        TAILQ_INSERT_TAIL(&sino->si_movs, srec, sr_next);
                        break;
                default:
                        err_suj("ino_build: Unknown op %d\n",
                            srec->sr_rec->rec_jrefrec.jr_op);
                }
        }
        if (TAILQ_EMPTY(&sino->si_recs))
                sino->si_hasrecs = 0;
}

/*
 * Modify journal records so they refer to the base block number
 * and a start and end frag range.  This is to facilitate the discovery
 * of overlapping fragment allocations.
 */
static void
blk_build(struct jblkrec *blkrec)
{
        struct suj_rec *srec;
        struct suj_blk *sblk;
        struct jblkrec *blkrn;
        ufs2_daddr_t blk;
        int frag;

        if (debug)
                printf("blk_build: op %d blkno %jd frags %d oldfrags %d "
                    "ino %ju lbn %jd\n",
                    blkrec->jb_op, (uintmax_t)blkrec->jb_blkno,
                    blkrec->jb_frags, blkrec->jb_oldfrags,
                    (uintmax_t)blkrec->jb_ino, (uintmax_t)blkrec->jb_lbn);

        blk = blknum(fs, blkrec->jb_blkno);
        frag = fragnum(fs, blkrec->jb_blkno);
        sblk = blk_lookup(blk, 1);
        /*
         * Rewrite the record using oldfrags to indicate the offset into
         * the block.  Leave jb_frags as the actual allocated count.
         */
        blkrec->jb_blkno -= frag;
        blkrec->jb_oldfrags = frag;
        if (blkrec->jb_oldfrags + blkrec->jb_frags > fs->fs_frag)
                err_suj("Invalid fragment count %d oldfrags %d\n",
                    blkrec->jb_frags, frag);
        /*
         * Detect dups.  If we detect a dup we always discard the oldest
         * record as it is superseded by the new record.  This speeds up
         * later stages but also eliminates free records which are used
         * to indicate that the contents of indirects can be trusted.
         */
        TAILQ_FOREACH(srec, &sblk->sb_recs, sr_next) {
                blkrn = (struct jblkrec *)srec->sr_rec;
                if (blkrn->jb_ino != blkrec->jb_ino ||
                    blkrn->jb_lbn != blkrec->jb_lbn ||
                    blkrn->jb_blkno != blkrec->jb_blkno ||
                    blkrn->jb_frags != blkrec->jb_frags ||
                    blkrn->jb_oldfrags != blkrec->jb_oldfrags)
                        continue;
                if (debug)
                        printf("Removed dup.\n");
                /* Discard the free which is a dup with an alloc. */
                if (blkrec->jb_op == JOP_FREEBLK)
                        return;
                TAILQ_REMOVE(&sblk->sb_recs, srec, sr_next);
                free(srec);
                break;
        }
        srec = errmalloc(sizeof(*srec));
        srec->sr_rec = (union jrec *)blkrec;
        TAILQ_INSERT_TAIL(&sblk->sb_recs, srec, sr_next);
}

static void
ino_build_trunc(struct jtrncrec *rec)
{
        struct suj_ino *sino;

        if (debug)
                printf("ino_build_trunc: op %d ino %ju, size %jd\n",
                    rec->jt_op, (uintmax_t)rec->jt_ino,
                    (uintmax_t)rec->jt_size);
        sino = ino_lookup(rec->jt_ino, 1);
        if (rec->jt_op == JOP_SYNC) {
                sino->si_trunc = NULL;
                return;
        }
        if (sino->si_trunc == NULL || sino->si_trunc->jt_size > rec->jt_size)
                sino->si_trunc = rec;
}

/*
 * Build up tables of the operations we need to recover.
 */
static void
suj_build(void)
{
        struct suj_seg *seg;
        union jrec *rec;
        int off;
        int i;

        TAILQ_FOREACH(seg, &allsegs, ss_next) {
                if (debug)
                        printf("seg %jd has %d records, oldseq %jd.\n",
                            seg->ss_rec.jsr_seq, seg->ss_rec.jsr_cnt,
                            seg->ss_rec.jsr_oldest);
                off = 0;
                rec = (union jrec *)seg->ss_blk;
                for (i = 0; i < seg->ss_rec.jsr_cnt; off += JREC_SIZE, rec++) {
                        /* skip the segrec. */
                        if ((off % real_dev_bsize) == 0)
                                continue;
                        switch (rec->rec_jrefrec.jr_op) {
                        case JOP_ADDREF:
                        case JOP_REMREF:
                        case JOP_MVREF:
                                ino_append(rec);
                                break;
                        case JOP_NEWBLK:
                        case JOP_FREEBLK:
                                blk_build((struct jblkrec *)rec);
                                break;
                        case JOP_TRUNC:
                        case JOP_SYNC:
                                ino_build_trunc((struct jtrncrec *)rec);
                                break;
                        default:
                                err_suj("Unknown journal operation %d (%d)\n",
                                    rec->rec_jrefrec.jr_op, off);
                        }
                        i++;
                }
        }
}

/*
 * Prune the journal segments to those we care about based on the
 * oldest sequence in the newest segment.  Order the segment list
 * based on sequence number.
 */
static void
suj_prune(void)
{
        struct suj_seg *seg;
        struct suj_seg *segn;
        uint64_t newseq;
        int discard;

        if (debug)
                printf("Pruning up to %jd\n", oldseq);
        /* First free the expired segments. */
        TAILQ_FOREACH_SAFE(seg, &allsegs, ss_next, segn) {
                if (seg->ss_rec.jsr_seq >= oldseq)
                        continue;
                TAILQ_REMOVE(&allsegs, seg, ss_next);
                free(seg->ss_blk);
                free(seg);
        }
        /* Next ensure that segments are ordered properly. */
        seg = TAILQ_FIRST(&allsegs);
        if (seg == NULL) {
                if (debug)
                        printf("Empty journal\n");
                return;
        }
        newseq = seg->ss_rec.jsr_seq;
        for (;;) {
                seg = TAILQ_LAST(&allsegs, seghd);
                if (seg->ss_rec.jsr_seq >= newseq)
                        break;
                TAILQ_REMOVE(&allsegs, seg, ss_next);
                TAILQ_INSERT_HEAD(&allsegs, seg, ss_next);
                newseq = seg->ss_rec.jsr_seq;

        }
        if (newseq != oldseq) {
                TAILQ_FOREACH(seg, &allsegs, ss_next) {
                        printf("%jd, ", seg->ss_rec.jsr_seq);
                }
                printf("\n");
                err_suj("Journal file sequence mismatch %jd != %jd\n",
                    newseq, oldseq);
        }
        /*
         * The kernel may asynchronously write segments which can create
         * gaps in the sequence space.  Throw away any segments after the
         * gap as the kernel guarantees only those that are contiguously
         * reachable are marked as completed.
         */
        discard = 0;
        TAILQ_FOREACH_SAFE(seg, &allsegs, ss_next, segn) {
                if (!discard && newseq++ == seg->ss_rec.jsr_seq) {
                        jrecs += seg->ss_rec.jsr_cnt;
                        jbytes += seg->ss_rec.jsr_blocks * real_dev_bsize;
                        continue;
                }
                discard = 1;
                if (debug)
                        printf("Journal order mismatch %jd != %jd pruning\n",
                            newseq-1, seg->ss_rec.jsr_seq);
                TAILQ_REMOVE(&allsegs, seg, ss_next);
                free(seg->ss_blk);
                free(seg);
        }
        if (debug)
                printf("Processing journal segments from %jd to %jd\n",
                    oldseq, newseq-1);
}

/*
 * Verify the journal inode before attempting to read records.
 */
static int
suj_verifyino(union dinode *dp)
{

        if (DIP(dp, di_nlink) != 1) {
                printf("Invalid link count %d for journal inode %ju\n",
                    DIP(dp, di_nlink), (uintmax_t)sujino);
                return (-1);
        }

        if ((DIP(dp, di_flags) & (SF_IMMUTABLE | SF_NOUNLINK)) !=
            (SF_IMMUTABLE | SF_NOUNLINK)) {
                printf("Invalid flags 0x%X for journal inode %ju\n",
                    DIP(dp, di_flags), (uintmax_t)sujino);
                return (-1);
        }

        if (DIP(dp, di_mode) != (IFREG | IREAD)) {
                printf("Invalid mode %o for journal inode %ju\n",
                    DIP(dp, di_mode), (uintmax_t)sujino);
                return (-1);
        }

        if (DIP(dp, di_size) < SUJ_MIN) {
                printf("Invalid size %jd for journal inode %ju\n",
                    DIP(dp, di_size), (uintmax_t)sujino);
                return (-1);
        }

        if (DIP(dp, di_modrev) != fs->fs_mtime) {
                printf("Journal timestamp does not match fs mount time\n");
                return (-1);
        }

        return (0);
}

struct jblocks {
        struct jextent *jb_extent;      /* Extent array. */
        int             jb_avail;       /* Available extents. */
        int             jb_used;        /* Last used extent. */
        int             jb_head;        /* Allocator head. */
        int             jb_off;         /* Allocator extent offset. */
};
struct jextent {
        ufs2_daddr_t    je_daddr;       /* Disk block address. */
        int             je_blocks;      /* Disk block count. */
};

static struct jblocks *suj_jblocks;

static struct jblocks *
jblocks_create(void)
{
        struct jblocks *jblocks;
        int size;

        jblocks = errmalloc(sizeof(*jblocks));
        jblocks->jb_avail = 10;
        jblocks->jb_used = 0;
        jblocks->jb_head = 0;
        jblocks->jb_off = 0;
        size = sizeof(struct jextent) * jblocks->jb_avail;
        jblocks->jb_extent = errmalloc(size);
        bzero(jblocks->jb_extent, size);

        return (jblocks);
}

/*
 * Return the next available disk block and the amount of contiguous
 * free space it contains.
 */
static ufs2_daddr_t
jblocks_next(struct jblocks *jblocks, int bytes, int *actual)
{
        struct jextent *jext;
        ufs2_daddr_t daddr;
        int freecnt;
        int blocks;

        blocks = btodb(bytes);
        jext = &jblocks->jb_extent[jblocks->jb_head];
        freecnt = jext->je_blocks - jblocks->jb_off;
        if (freecnt == 0) {
                jblocks->jb_off = 0;
                if (++jblocks->jb_head > jblocks->jb_used)
                        return (0);
                jext = &jblocks->jb_extent[jblocks->jb_head];
                freecnt = jext->je_blocks;
        }
        if (freecnt > blocks)
                freecnt = blocks;
        *actual = dbtob(freecnt);
        daddr = jext->je_daddr + jblocks->jb_off;

        return (daddr);
}

/*
 * Advance the allocation head by a specified number of bytes, consuming
 * one journal segment.
 */
static void
jblocks_advance(struct jblocks *jblocks, int bytes)
{

        jblocks->jb_off += btodb(bytes);
}

static void
jblocks_destroy(struct jblocks *jblocks)
{

        free(jblocks->jb_extent);
        free(jblocks);
}

static void
jblocks_add(struct jblocks *jblocks, ufs2_daddr_t daddr, int blocks)
{
        struct jextent *jext;
        int size;

        jext = &jblocks->jb_extent[jblocks->jb_used];
        /* Adding the first block. */
        if (jext->je_daddr == 0) {
                jext->je_daddr = daddr;
                jext->je_blocks = blocks;
                return;
        }
        /* Extending the last extent. */
        if (jext->je_daddr + jext->je_blocks == daddr) {
                jext->je_blocks += blocks;
                return;
        }
        /* Adding a new extent. */
        if (++jblocks->jb_used == jblocks->jb_avail) {
                jblocks->jb_avail *= 2;
                size = sizeof(struct jextent) * jblocks->jb_avail;
                jext = errmalloc(size);
                bzero(jext, size);
                bcopy(jblocks->jb_extent, jext,
                    sizeof(struct jextent) * jblocks->jb_used);
                free(jblocks->jb_extent);
                jblocks->jb_extent = jext;
        }
        jext = &jblocks->jb_extent[jblocks->jb_used];
        jext->je_daddr = daddr;
        jext->je_blocks = blocks;

        return;
}

/*
 * Add a file block from the journal to the extent map.  We can't read
 * each file block individually because the kernel treats it as a circular
 * buffer and segments may span mutliple contiguous blocks.
 */
static void
suj_add_block(ino_t ino, ufs_lbn_t lbn, ufs2_daddr_t blk, int frags)
{

        jblocks_add(suj_jblocks, fsbtodb(fs, blk), fsbtodb(fs, frags));
}

static void
suj_read(void)
{
        uint8_t block[1 * 1024 * 1024];
        struct suj_seg *seg;
        struct jsegrec *recn;
        struct jsegrec *rec;
        ufs2_daddr_t blk;
        int readsize;
        int blocks;
        int recsize;
        int size;
        int i;

        /*
         * Read records until we exhaust the journal space.  If we find
         * an invalid record we start searching for a valid segment header
         * at the next block.  This is because we don't have a head/tail
         * pointer and must recover the information indirectly.  At the gap
         * between the head and tail we won't necessarily have a valid
         * segment.
         */
restart:
        for (;;) {
                size = sizeof(block);
                blk = jblocks_next(suj_jblocks, size, &readsize);
                if (blk == 0)
                        return;
                size = readsize;
                /*
                 * Read 1MB at a time and scan for records within this block.
                 */
                if (pread(fsreadfd, &block, size, dbtob(blk)) != size) {
                        err_suj("Error reading journal block %jd\n",
                            (intmax_t)blk);
                }
                for (rec = (void *)block; size; size -= recsize,
                    rec = (struct jsegrec *)((uintptr_t)rec + recsize)) {
                        recsize = real_dev_bsize;
                        if (rec->jsr_time != fs->fs_mtime) {
#ifdef notdef
                                if (debug)
                                        printf("Rec time %jd != fs mtime %jd\n",
                                            rec->jsr_time, fs->fs_mtime);
#endif
                                jblocks_advance(suj_jblocks, recsize);
                                continue;
                        }
                        if (rec->jsr_cnt == 0) {
                                if (debug)
                                        printf("Found illegal count %d\n",
                                            rec->jsr_cnt);
                                jblocks_advance(suj_jblocks, recsize);
                                continue;
                        }
                        blocks = rec->jsr_blocks;
                        recsize = blocks * real_dev_bsize;
                        if (recsize > size) {
                                /*
                                 * We may just have run out of buffer, restart
                                 * the loop to re-read from this spot.
                                 */
                                if (size < fs->fs_bsize &&
                                    size != readsize &&
                                    recsize <= fs->fs_bsize)
                                        goto restart;
                                if (debug)
                                        printf("Found invalid segsize %d > %d\n",
                                            recsize, size);
                                recsize = real_dev_bsize;
                                jblocks_advance(suj_jblocks, recsize);
                                continue;
                        }
                        /*
                         * Verify that all blocks in the segment are present.
                         */
                        for (i = 1; i < blocks; i++) {
                                recn = (void *)((uintptr_t)rec) + i *
                                    real_dev_bsize;
                                if (recn->jsr_seq == rec->jsr_seq &&
                                    recn->jsr_time == rec->jsr_time)
                                        continue;
                                if (debug)
                                        printf("Incomplete record %jd (%d)\n",
                                            rec->jsr_seq, i);
                                recsize = i * real_dev_bsize;
                                jblocks_advance(suj_jblocks, recsize);
                                goto restart;
                        }
                        seg = errmalloc(sizeof(*seg));
                        seg->ss_blk = errmalloc(recsize);
                        seg->ss_rec = *rec;
                        bcopy((void *)rec, seg->ss_blk, recsize);
                        if (rec->jsr_oldest > oldseq)
                                oldseq = rec->jsr_oldest;
                        TAILQ_INSERT_TAIL(&allsegs, seg, ss_next);
                        jblocks_advance(suj_jblocks, recsize);
                }
        }
}

/*
 * Orchestrate the verification of a filesystem via the softupdates journal.
 */
int
suj_check(const char *filesys)
{
        struct inodesc idesc;
        struct csum *cgsum;
        union dinode *jip;
        struct inode ip;
        uint64_t blocks;
        int i, retval;
        struct suj_seg *seg;
        struct suj_seg *segn;

        initsuj();
        fs = &sblock;
        if (real_dev_bsize == 0 && ioctl(fsreadfd, DIOCGSECTORSIZE,
            &real_dev_bsize) == -1)
                real_dev_bsize = secsize;
        if (debug)
                printf("dev_bsize %u\n", real_dev_bsize);

        /*
         * Set an exit point when SUJ check failed
         */
        retval = setjmp(jmpbuf);
        if (retval != 0) {
                pwarn("UNEXPECTED SU+J INCONSISTENCY\n");
                TAILQ_FOREACH_SAFE(seg, &allsegs, ss_next, segn) {
                        TAILQ_REMOVE(&allsegs, seg, ss_next);
                                free(seg->ss_blk);
                                free(seg);
                }
                if (reply("FALLBACK TO FULL FSCK") == 0) {
                        ckfini(0);
                        exit(EEXIT);
                } else
                        return (-1);
        }

        /*
         * Search the root directory for the SUJ_FILE.
         */
        idesc.id_type = DATA;
        idesc.id_fix = IGNORE;
        idesc.id_number = UFS_ROOTINO;
        idesc.id_func = findino;
        idesc.id_name = SUJ_FILE;
        ginode(UFS_ROOTINO, &ip);
        if ((ckinode(ip.i_dp, &idesc) & FOUND) == FOUND) {
                sujino = idesc.id_parent;
                irelse(&ip);
        } else {
                printf("Journal inode removed.  Use tunefs to re-create.\n");
                sblock.fs_flags &= ~FS_SUJ;
                sblock.fs_sujfree = 0;
                irelse(&ip);
                return (-1);
        }
        /*
         * Fetch the journal inode and verify it.
         */
        ginode(sujino, &ip);
        jip = ip.i_dp;
        printf("** SU+J Recovering %s\n", filesys);
        if (suj_verifyino(jip) != 0 || (!preen && !reply("USE JOURNAL"))) {
                irelse(&ip);
                return (-1);
        }
        /*
         * Build a list of journal blocks in jblocks before parsing the
         * available journal blocks in with suj_read().
         */
        printf("** Reading %jd byte journal from inode %ju.\n",
            DIP(jip, di_size), (uintmax_t)sujino);
        suj_jblocks = jblocks_create();
        blocks = ino_visit(jip, sujino, suj_add_block, 0);
        if (blocks != numfrags(fs, DIP(jip, di_size))) {
                printf("Sparse journal inode %ju.\n", (uintmax_t)sujino);
                irelse(&ip);
                return (-1);
        }
        irelse(&ip);
        suj_read();
        jblocks_destroy(suj_jblocks);
        suj_jblocks = NULL;
        if (preen || reply("RECOVER")) {
                printf("** Building recovery table.\n");
                suj_prune();
                suj_build();
                cg_apply(cg_build);
                printf("** Resolving unreferenced inode list.\n");
                ino_unlinked();
                printf("** Processing journal entries.\n");
                cg_apply(cg_trunc);
                cg_apply(cg_check_blk);
                cg_apply(cg_adj_blk);
                cg_apply(cg_check_ino);
        }
        if (preen == 0 && (jrecs > 0 || jbytes > 0) && reply("WRITE CHANGES") == 0)
                return (0);
        /*
         * Recompute the fs summary info from correct cs summaries.
         */
        bzero(&fs->fs_cstotal, sizeof(struct csum_total));
        for (i = 0; i < fs->fs_ncg; i++) {
                cgsum = &fs->fs_cs(fs, i);
                fs->fs_cstotal.cs_nffree += cgsum->cs_nffree;
                fs->fs_cstotal.cs_nbfree += cgsum->cs_nbfree;
                fs->fs_cstotal.cs_nifree += cgsum->cs_nifree;
                fs->fs_cstotal.cs_ndir += cgsum->cs_ndir;
        }
        fs->fs_pendinginodes = 0;
        fs->fs_pendingblocks = 0;
        fs->fs_clean = 1;
        fs->fs_time = time(NULL);
        fs->fs_mtime = time(NULL);
        sbdirty();
        ckfini(1);
        if (jrecs > 0 || jbytes > 0) {
                printf("** %jd journal records in %jd bytes for %.2f%% utilization\n",
                    jrecs, jbytes, ((float)jrecs / (float)(jbytes / JREC_SIZE)) * 100);
                printf("** Freed %jd inodes (%jd dirs) %jd blocks, and %jd frags.\n",
                    freeinos, freedir, freeblocks, freefrags);
        }

        return (0);
}

static void
initsuj(void)
{
        int i;

        for (i = 0; i < HASHSIZE; i++)
                LIST_INIT(&cghash[i]);
        lastcg = NULL;
        TAILQ_INIT(&allsegs);
        oldseq = 0;
        fs = NULL;
        sujino = 0;
        freefrags = 0;
        freeblocks = 0;
        freeinos = 0;
        freedir = 0;
        jbytes = 0;
        jrecs = 0;
        suj_jblocks = NULL;
}