/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
/*        All Rights Reserved   */

/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

#include <sys/types.h>
#include <sys/t_lock.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/fs/ufs_fs.h>
#include <sys/cmn_err.h>

#ifdef _KERNEL

#include <sys/systm.h>
#include <sys/sysmacros.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/user.h>
#include <sys/var.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/debug.h>
#include <sys/fssnap_if.h>
#include <sys/fs/ufs_inode.h>
#include <sys/fs/ufs_trans.h>
#include <sys/fs/ufs_panic.h>
#include <sys/fs/ufs_bio.h>
#include <sys/fs/ufs_log.h>
#include <sys/kmem.h>
#include <sys/policy.h>
#include <vm/hat.h>
#include <vm/as.h>
#include <vm/seg.h>
#include <vm/pvn.h>
#include <vm/seg_map.h>
#include <sys/swap.h>
#include <vm/seg_kmem.h>

#else  /* _KERNEL */

#define ASSERT(x)               /* don't use asserts for fsck et al */

#endif  /* _KERNEL */

#ifdef _KERNEL

/*
 * Used to verify that a given entry on the ufs_instances list (see below)
 * still refers to a mounted file system.
 *
 * XXX: This is a crock that substitutes for proper locking to coordinate
 *      updates to and uses of the entries in ufs_instances.
 */
struct check_node {
        struct vfs *vfsp;
        struct ufsvfs *ufsvfs;
        dev_t vfs_dev;
};

static vfs_t *still_mounted(struct check_node *);

/*
 * All ufs file system instances are linked together into a list starting at
 * ufs_instances.  The list is updated as part of mount and unmount.  It's
 * consulted in ufs_update, to allow syncing out all ufs file system instances
 * in a batch.
 *
 * ufsvfs_mutex guards access to this list and to the {,old}ufsvfslist
 * manipulated in ufs_funmount_cleanup.  (A given ufs instance is always on
 * exactly one of these lists except while it's being allocated or
 * deallocated.)
 */
struct ufsvfs   *ufs_instances;
extern kmutex_t         ufsvfs_mutex;   /* XXX: move this to ufs_inode.h? */

/*
 * ufsvfs list manipulation routines
 */

/*
 * Link ufsp in at the head of the list of ufs_instances.
 */
void
ufs_vfs_add(struct ufsvfs *ufsp)
{
        mutex_enter(&ufsvfs_mutex);
        ufsp->vfs_next = ufs_instances;
        ufs_instances = ufsp;
        mutex_exit(&ufsvfs_mutex);
}

/*
 * Remove ufsp from the list of ufs_instances.
 *
 * Does no error checking; ufsp is assumed to actually be on the list.
 */
void
ufs_vfs_remove(struct ufsvfs *ufsp)
{
        struct ufsvfs   **delpt = &ufs_instances;

        mutex_enter(&ufsvfs_mutex);
        for (; *delpt != NULL; delpt = &((*delpt)->vfs_next)) {
                if (*delpt == ufsp) {
                        *delpt = ufsp->vfs_next;
                        ufsp->vfs_next = NULL;
                        break;
                }
        }
        mutex_exit(&ufsvfs_mutex);
}

/*
 * Clean up state resulting from a forcible unmount that couldn't be handled
 * directly during the unmount.  (See commentary in the unmount code for more
 * info.)
 */
static void
ufs_funmount_cleanup()
{
        struct ufsvfs           *ufsvfsp;
        extern struct ufsvfs    *oldufsvfslist, *ufsvfslist;

        /*
         * Assumption: it's now safe to blow away the entries on
         * oldufsvfslist.
         */
        mutex_enter(&ufsvfs_mutex);
        while ((ufsvfsp = oldufsvfslist) != NULL) {
                oldufsvfslist = ufsvfsp->vfs_next;

                mutex_destroy(&ufsvfsp->vfs_lock);
                kmem_free(ufsvfsp, sizeof (struct ufsvfs));
        }
        /*
         * Rotate more recent unmount entries into place in preparation for
         * the next time around.
         */
        oldufsvfslist = ufsvfslist;
        ufsvfslist = NULL;
        mutex_exit(&ufsvfs_mutex);
}


/*
 * ufs_update performs the ufs part of `sync'.  It goes through the disk
 * queues to initiate sandbagged IO; goes through the inodes to write
 * modified nodes; and it goes through the mount table to initiate
 * the writing of the modified super blocks.
 */
extern time_t   time;
time_t          ufs_sync_time;
time_t          ufs_sync_time_secs = 1;

extern kmutex_t ufs_scan_lock;

void
ufs_update(int flag)
{
        struct vfs *vfsp;
        struct fs *fs;
        struct ufsvfs *ufsp;
        struct ufsvfs *ufsnext;
        struct ufsvfs *update_list = NULL;
        int check_cnt = 0;
        size_t check_size;
        struct check_node *check_list, *ptr;
        int cheap = flag & SYNC_ATTR;

        /*
         * This is a hack.  A design flaw in the forced unmount protocol
         * could allow a thread to attempt to use a kmem_freed ufsvfs
         * structure in ufs_lockfs_begin/ufs_check_lockfs.  This window
         * is difficult to hit, even during the lockfs stress tests.
         * So the hacky fix is to wait awhile before kmem_free'ing the
         * ufsvfs structures for forcibly unmounted file systems.  `Awhile'
         * is defined as every other call from fsflush (~60 seconds).
         */
        if (cheap)
                ufs_funmount_cleanup();

        /*
         * Examine all ufsvfs structures and add those that we can lock to the
         * update list.  This is so that we don't hold the list lock for a
         * long time.  If vfs_lock fails for a file system instance, then skip
         * it because somebody is doing a unmount on it.
         */
        mutex_enter(&ufsvfs_mutex);
        for (ufsp = ufs_instances; ufsp != NULL; ufsp = ufsp->vfs_next) {
                vfsp = ufsp->vfs_vfs;
                if (vfs_lock(vfsp) != 0)
                        continue;
                ufsp->vfs_wnext = update_list;
                update_list = ufsp;
                check_cnt++;
        }
        mutex_exit(&ufsvfs_mutex);

        if (update_list == NULL)
                return;

        check_size = sizeof (struct check_node) * check_cnt;
        check_list = ptr = kmem_alloc(check_size, KM_NOSLEEP);

        /*
         * Write back modified superblocks.
         * Consistency check that the superblock of
         * each file system is still in the buffer cache.
         *
         * Note that the update_list traversal is done without the protection
         * of an overall list lock, so it's necessary to rely on the fact that
         * each entry of the list is vfs_locked when moving from one entry to
         * the next.  This works because a concurrent attempt to add an entry
         * to another thread's update_list won't find it, since it'll already
         * be locked.
         */
        check_cnt = 0;
        for (ufsp = update_list; ufsp != NULL; ufsp = ufsnext) {
                /*
                 * Need to grab the next ptr before we unlock this one so
                 * another thread doesn't grab it and change it before we move
                 * on to the next vfs.  (Once we unlock it, it's ok if another
                 * thread finds it to add it to its own update_list; we don't
                 * attempt to refer to it through our list any more.)
                 */
                ufsnext = ufsp->vfs_wnext;
                vfsp = ufsp->vfs_vfs;

                /*
                 * Seems like this can't happen, so perhaps it should become
                 * an ASSERT(vfsp->vfs_data != NULL).
                 */
                if (!vfsp->vfs_data) {
                        vfs_unlock(vfsp);
                        continue;
                }

                fs = ufsp->vfs_fs;

                /*
                 * don't update a locked superblock during a panic; it
                 * may be in an inconsistent state
                 */
                if (panicstr) {
                        if (!mutex_tryenter(&ufsp->vfs_lock)) {
                                vfs_unlock(vfsp);
                                continue;
                        }
                } else
                        mutex_enter(&ufsp->vfs_lock);
                /*
                 * Build up the STABLE check list, so we can unlock the vfs
                 * until we do the actual checking.
                 */
                if (check_list != NULL) {
                        if ((fs->fs_ronly == 0) &&
                            (fs->fs_clean != FSBAD) &&
                            (fs->fs_clean != FSSUSPEND)) {
                                ptr->vfsp = vfsp;
                                ptr->ufsvfs = ufsp;
                                ptr->vfs_dev = vfsp->vfs_dev;
                                ptr++;
                                check_cnt++;
                        }
                }

                /*
                 * superblock is not modified
                 */
                if (fs->fs_fmod == 0) {
                        mutex_exit(&ufsp->vfs_lock);
                        vfs_unlock(vfsp);
                        continue;
                }
                if (fs->fs_ronly != 0) {
                        mutex_exit(&ufsp->vfs_lock);
                        vfs_unlock(vfsp);
                        (void) ufs_fault(ufsp->vfs_root,
                            "fs = %s update: ro fs mod\n", fs->fs_fsmnt);
                        /*
                         * XXX: Why is this a return instead of a continue?
                         *      This may be an attempt to replace a panic with
                         *      something less drastic, but there's cleanup we
                         *      should be doing that's not being done (e.g.,
                         *      unlocking the remaining entries on the list).
                         */
                        return;
                }
                fs->fs_fmod = 0;
                mutex_exit(&ufsp->vfs_lock);
                TRANS_SBUPDATE(ufsp, vfsp, TOP_SBUPDATE_UPDATE);
                vfs_unlock(vfsp);
        }

        ufs_sync_time = time;

        /*
         * Avoid racing with ufs_unmount() and ufs_sync().
         */
        mutex_enter(&ufs_scan_lock);

        (void) ufs_scan_inodes(1, ufs_sync_inode, (void *)(uintptr_t)cheap,
            NULL);

        mutex_exit(&ufs_scan_lock);

        /*
         * Force stale buffer cache information to be flushed,
         * for all devices.  This should cause any remaining control
         * information (e.g., cg and inode info) to be flushed back.
         */
        bflush((dev_t)NODEV);

        if (check_list == NULL)
                return;

        /*
         * For each UFS filesystem in the STABLE check_list, update
         * the clean flag if warranted.
         */
        for (ptr = check_list; check_cnt > 0; check_cnt--, ptr++) {
                int     error;

                /*
                 * still_mounted() returns with vfsp and the vfs_reflock
                 * held if ptr refers to a vfs that is still mounted.
                 */
                if ((vfsp = still_mounted(ptr)) == NULL)
                        continue;
                ufs_checkclean(vfsp);
                /*
                 * commit any outstanding async transactions
                 */
                ufsp = (struct ufsvfs *)vfsp->vfs_data;
                curthread->t_flag |= T_DONTBLOCK;
                TRANS_BEGIN_SYNC(ufsp, TOP_COMMIT_UPDATE, TOP_COMMIT_SIZE,
                    error);
                if (!error) {
                        TRANS_END_SYNC(ufsp, error, TOP_COMMIT_UPDATE,
                            TOP_COMMIT_SIZE);
                }
                curthread->t_flag &= ~T_DONTBLOCK;

                vfs_unlock(vfsp);
        }

        kmem_free(check_list, check_size);
}

int
ufs_sync_inode(struct inode *ip, void *arg)
{
        int cheap = (int)(uintptr_t)arg;
        struct ufsvfs *ufsvfsp;
        uint_t flag = ip->i_flag;

        if (cheap && ((flag & (IUPD|IACC|ICHG|IMOD|IMODACC|IATTCHG)) == 0))
                return (0);

        /*
         * if we are panic'ing; then don't update the inode if this
         * file system is FSSTABLE.  Otherwise, we would have to
         * force the superblock to FSACTIVE and the superblock
         * may not be in a good state.  Also, if the inode is
         * IREF'ed then it may be in an inconsistent state.  Don't
         * push it.  Finally, don't push the inode if the fs is
         * logging; the transaction will be discarded at boot.
         */
        if (panicstr) {

                if (flag & IREF)
                        return (0);

                if (ip->i_ufsvfs == NULL ||
                    (ip->i_fs->fs_clean == FSSTABLE ||
                    ip->i_fs->fs_clean == FSLOG))
                                return (0);
        }

        ufsvfsp = ip->i_ufsvfs;

        /*
         * Limit access time only updates
         */
        if (((flag & (IMOD|IMODACC|IUPD|ICHG|IACC)) == IMODACC) && ufsvfsp) {
                /*
                 * if file system has deferred access time turned on and there
                 * was no IO recently, don't bother flushing it. It will be
                 * flushed when I/Os start again.
                 */
                if (cheap && (ufsvfsp->vfs_dfritime & UFS_DFRATIME) &&
                    (ufsvfsp->vfs_iotstamp + ufs_iowait < ddi_get_lbolt()))
                        return (0);
                /*
                 * an app issueing a sync() can take forever on a trans device
                 * when NetWorker or find is running because all of the
                 * directorys' access times have to be updated. So, we limit
                 * the time we spend updating access times per sync.
                 */
                if (TRANS_ISTRANS(ufsvfsp) && ((ufs_sync_time +
                    ufs_sync_time_secs) < time))
                        return (0);
        }

        /*
         * if we are running on behalf of the flush thread or this is
         * a swap file, then simply do a delay update of the inode.
         * Otherwise, push the pages and then do a delayed inode update.
         */
        if (cheap || IS_SWAPVP(ITOV(ip))) {
                TRANS_IUPDAT(ip, 0);
        } else {
                (void) TRANS_SYNCIP(ip, B_ASYNC, I_ASYNC, TOP_SYNCIP_SYNC);
        }
        return (0);
}

/*
 * Flush all the pages associated with an inode using the given 'flags',
 * then force inode information to be written back using the given 'waitfor'.
 */
int
ufs_syncip(struct inode *ip, int flags, int waitfor, top_t topid)
{
        int     error;
        struct vnode *vp = ITOV(ip);
        struct ufsvfs *ufsvfsp = ip->i_ufsvfs;
        int dotrans = 0;

        /*
         * Return if file system has been forcibly umounted.
         */
        if (ufsvfsp == NULL)
                return (EIO);
        /*
         * don't need to VOP_PUTPAGE if there are no pages
         */
        if (!vn_has_cached_data(vp) || vp->v_type == VCHR) {
                error = 0;
        } else {
                /*
                 * if the inode we're working on is a shadow inode
                 * or quota inode we need to make sure that the
                 * ufs_putpage call is inside a transaction as this
                 * could include meta data changes.
                 */
                if ((ip->i_mode & IFMT) == IFSHAD ||
                    ufsvfsp->vfs_qinod == ip) {
                        dotrans = 1;
                        curthread->t_flag |= T_DONTBLOCK;
                        TRANS_BEGIN_ASYNC(ufsvfsp, TOP_PUTPAGE,
                            TOP_PUTPAGE_SIZE(ip));
                }
                error = VOP_PUTPAGE(vp, (offset_t)0, (size_t)0,
                    flags, CRED(), NULL);
                if (dotrans) {
                        TRANS_END_ASYNC(ufsvfsp, TOP_PUTPAGE,
                            TOP_PUTPAGE_SIZE(ip));
                        curthread->t_flag &= ~T_DONTBLOCK;
                        dotrans = 0;
                }
        }
        if (panicstr && TRANS_ISTRANS(ufsvfsp))
                goto out;
        /*
         * waitfor represents two things -
         * 1. whether data sync or file sync.
         * 2. if file sync then ufs_iupdat should 'waitfor' disk i/o or not.
         */
        if (waitfor == I_DSYNC) {
                /*
                 * If data sync, only IATTCHG (size/block change) requires
                 * inode update, fdatasync()/FDSYNC implementation.
                 */
                if (ip->i_flag & (IBDWRITE|IATTCHG)) {
                        /*
                         * Enter a transaction to provide mutual exclusion
                         * with deltamap_push and avoid a race where
                         * the inode flush could get dropped.
                         */
                        if ((curthread->t_flag & T_DONTBLOCK) == 0) {
                                dotrans = 1;
                                curthread->t_flag |= T_DONTBLOCK;
                                TRANS_BEGIN_ASYNC(ufsvfsp, topid,
                                    TOP_SYNCIP_SIZE);
                        }
                        rw_enter(&ip->i_contents, RW_READER);
                        mutex_enter(&ip->i_tlock);
                        ip->i_flag &= ~IMODTIME;
                        mutex_exit(&ip->i_tlock);
                        ufs_iupdat(ip, 1);
                        rw_exit(&ip->i_contents);
                        if (dotrans) {
                                TRANS_END_ASYNC(ufsvfsp, topid,
                                    TOP_SYNCIP_SIZE);
                                curthread->t_flag &= ~T_DONTBLOCK;
                        }
                }
        } else {
                /* For file sync, any inode change requires inode update */
                if (ip->i_flag & (IBDWRITE|IUPD|IACC|ICHG|IMOD|IMODACC)) {
                        /*
                         * Enter a transaction to provide mutual exclusion
                         * with deltamap_push and avoid a race where
                         * the inode flush could get dropped.
                         */
                        if ((curthread->t_flag & T_DONTBLOCK) == 0) {
                                dotrans = 1;
                                curthread->t_flag |= T_DONTBLOCK;
                                TRANS_BEGIN_ASYNC(ufsvfsp, topid,
                                    TOP_SYNCIP_SIZE);
                        }
                        rw_enter(&ip->i_contents, RW_READER);
                        mutex_enter(&ip->i_tlock);
                        ip->i_flag &= ~IMODTIME;
                        mutex_exit(&ip->i_tlock);
                        ufs_iupdat(ip, waitfor);
                        rw_exit(&ip->i_contents);
                        if (dotrans) {
                                TRANS_END_ASYNC(ufsvfsp, topid,
                                    TOP_SYNCIP_SIZE);
                                curthread->t_flag &= ~T_DONTBLOCK;
                        }
                }
        }

out:
        return (error);
}
/*
 * Flush all indirect blocks related to an inode.
 * Supports triple indirect blocks also.
 */
int
ufs_sync_indir(struct inode *ip)
{
        int i;
        daddr_t blkno;
        daddr_t lbn;    /* logical blkno of last blk in file */
        daddr_t clbn;   /* current logical blk */
        daddr32_t *bap;
        struct fs *fs;
        struct buf *bp;
        int bsize;
        struct ufsvfs *ufsvfsp;
        int j;
        daddr_t indirect_blkno;
        daddr32_t *indirect_bap;
        struct buf *indirect_bp;

        ufsvfsp = ip->i_ufsvfs;
        /*
         * unnecessary when logging; allocation blocks are kept up-to-date
         */
        if (TRANS_ISTRANS(ufsvfsp))
                return (0);

        fs = ufsvfsp->vfs_fs;
        bsize = fs->fs_bsize;
        lbn = (daddr_t)lblkno(fs, ip->i_size - 1);
        if (lbn < NDADDR)
                return (0);     /* No indirect blocks used */
        if (lbn < NDADDR + NINDIR(fs)) {
                /* File has one indirect block. */
                blkflush(ip->i_dev, (daddr_t)fsbtodb(fs, ip->i_ib[0]));
                return (0);
        }

        /* Write out all the first level indirect blocks */
        for (i = 0; i < NIADDR; i++) {
                if ((blkno = ip->i_ib[i]) == 0)
                        continue;
                blkflush(ip->i_dev, (daddr_t)fsbtodb(fs, blkno));
        }
        /* Write out second level of indirect blocks */
        if ((blkno = ip->i_ib[1]) == 0)
                return (0);
        bp = UFS_BREAD(ufsvfsp, ip->i_dev, (daddr_t)fsbtodb(fs, blkno), bsize);
        if (bp->b_flags & B_ERROR) {
                brelse(bp);
                return (EIO);
        }
        bap = bp->b_un.b_daddr;
        clbn = NDADDR + NINDIR(fs);
        for (i = 0; i < NINDIR(fs); i++) {
                if (clbn > lbn)
                        break;
                clbn += NINDIR(fs);
                if ((blkno = bap[i]) == 0)
                        continue;
                blkflush(ip->i_dev, (daddr_t)fsbtodb(fs, blkno));
        }

        brelse(bp);
        /* write out third level indirect blocks */

        if ((blkno = ip->i_ib[2]) == 0)
                return (0);

        bp = UFS_BREAD(ufsvfsp, ip->i_dev, (daddr_t)fsbtodb(fs, blkno), bsize);
        if (bp->b_flags & B_ERROR) {
                brelse(bp);
                return (EIO);
        }
        bap = bp->b_un.b_daddr;
        clbn = NDADDR + NINDIR(fs) + (NINDIR(fs) * NINDIR(fs));

        for (i = 0; i < NINDIR(fs); i++) {
                if (clbn > lbn)
                        break;
                if ((indirect_blkno = bap[i]) == 0)
                        continue;
                blkflush(ip->i_dev, (daddr_t)fsbtodb(fs, indirect_blkno));
                indirect_bp = UFS_BREAD(ufsvfsp, ip->i_dev,
                    (daddr_t)fsbtodb(fs, indirect_blkno), bsize);
                if (indirect_bp->b_flags & B_ERROR) {
                        brelse(indirect_bp);
                        brelse(bp);
                        return (EIO);
                }
                indirect_bap = indirect_bp->b_un.b_daddr;
                for (j = 0; j < NINDIR(fs); j++) {
                        if (clbn > lbn)
                                break;
                        clbn += NINDIR(fs);
                        if ((blkno = indirect_bap[j]) == 0)
                                continue;
                        blkflush(ip->i_dev, (daddr_t)fsbtodb(fs, blkno));
                }
                brelse(indirect_bp);
        }
        brelse(bp);

        return (0);
}

/*
 * Flush all indirect blocks related to an offset of a file.
 * read/write in sync mode may have to flush indirect blocks.
 */
int
ufs_indirblk_sync(struct inode *ip, offset_t off)
{
        daddr_t lbn;
        struct  fs *fs;
        struct  buf *bp;
        int     i, j, shft;
        daddr_t ob, nb, tbn;
        daddr32_t *bap;
        int     nindirshift, nindiroffset;
        struct ufsvfs *ufsvfsp;

        ufsvfsp = ip->i_ufsvfs;
        /*
         * unnecessary when logging; allocation blocks are kept up-to-date
         */
        if (TRANS_ISTRANS(ufsvfsp))
                return (0);

        fs = ufsvfsp->vfs_fs;

        lbn = (daddr_t)lblkno(fs, off);
        if (lbn < 0)
                return (EFBIG);

        /* The first NDADDR are direct so nothing to do */
        if (lbn < NDADDR)
                return (0);

        nindirshift = ip->i_ufsvfs->vfs_nindirshift;
        nindiroffset = ip->i_ufsvfs->vfs_nindiroffset;

        /* Determine level of indirect blocks */
        shft = 0;
        tbn = lbn - NDADDR;
        for (j = NIADDR; j > 0; j--) {
                longlong_t      sh;

                shft += nindirshift;
                sh = 1LL << shft;
                if (tbn < sh)
                        break;
                tbn -= (daddr_t)sh;
        }

        if (j == 0)
                return (EFBIG);

        if ((nb = ip->i_ib[NIADDR - j]) == 0)
                        return (0);             /* UFS Hole */

        /* Flush first level indirect block */
        blkflush(ip->i_dev, fsbtodb(fs, nb));

        /* Fetch through next levels */
        for (; j < NIADDR; j++) {
                ob = nb;
                bp = UFS_BREAD(ufsvfsp,
                    ip->i_dev, fsbtodb(fs, ob), fs->fs_bsize);
                if (bp->b_flags & B_ERROR) {
                        brelse(bp);
                        return (EIO);
                }
                bap = bp->b_un.b_daddr;
                shft -= nindirshift;            /* sh / nindir */
                i = (tbn >> shft) & nindiroffset; /* (tbn /sh) & nindir */
                nb = bap[i];
                brelse(bp);
                if (nb == 0) {
                        return (0);             /* UFS hole */
                }
                blkflush(ip->i_dev, fsbtodb(fs, nb));
        }
        return (0);
}

#ifdef DEBUG

/*
 * The bad block checking routines: ufs_indir_badblock() and ufs_badblock()
 * are very expensive. It's been found from profiling that we're
 * spending 6-7% of our time in ufs_badblock, and another 1-2% in
 * ufs_indir_badblock. They are only called via ASSERTs (from debug kernels).
 * In addition from experience no failures have been found in recent
 * years. So the following tunable can be set to enable checking.
 */
int ufs_badblock_checks = 0;

/*
 * Check that a given indirect block contains blocks in range
 */
int
ufs_indir_badblock(struct inode *ip, daddr32_t *bap)
{
        int i;
        int err = 0;

        if (ufs_badblock_checks) {
                for (i = 0; i < NINDIR(ip->i_fs) - 1; i++)
                        if (bap[i] != 0 && (err = ufs_badblock(ip, bap[i])))
                                break;
        }
        return (err);
}

/*
 * Check that a specified block number is in range.
 */
int
ufs_badblock(struct inode *ip, daddr_t bn)
{
        long    c;
        daddr_t sum;

        if (!ufs_badblock_checks)
                return (0);
        ASSERT(bn);
        if (bn <= 0 || bn > ip->i_fs->fs_size)
                return (bn);

        sum = 0;
        c = dtog(ip->i_fs, bn);
        if (c == 0) {
                sum = howmany(ip->i_fs->fs_cssize, ip->i_fs->fs_fsize);
        }
        /*
         * if block no. is below this cylinder group,
         * within the space reserved for superblock, inodes, (summary data)
         * or if it is above this cylinder group
         * then its invalid
         * It's hard to see how we'd be outside this cyl, but let's be careful.
         */
        if ((bn < cgbase(ip->i_fs, c)) ||
            (bn >= cgsblock(ip->i_fs, c) && bn < cgdmin(ip->i_fs, c)+sum) ||
            (bn >= (unsigned)cgbase(ip->i_fs, c+1)))
                return (bn);

        return (0);     /* not a bad block */
}

#endif /* DEBUG */

/*
 * When i_rwlock is write-locked or has a writer pended, then the inode
 * is going to change in a way that the filesystem will be marked as
 * active. So no need to let the filesystem be mark as stable now.
 * Also to ensure the filesystem consistency during the directory
 * operations, filesystem cannot be marked as stable if i_rwlock of
 * the directory inode is write-locked.
 */

/*
 * Check for busy inodes for this filesystem.
 * NOTE: Needs better way to do this expensive operation in the future.
 */
static void
ufs_icheck(struct ufsvfs *ufsvfsp, int *isbusyp, int *isreclaimp)
{
        union  ihead    *ih;
        struct inode    *ip;
        int             i;
        int             isnottrans      = !TRANS_ISTRANS(ufsvfsp);
        int             isbusy          = *isbusyp;
        int             isreclaim       = *isreclaimp;

        for (i = 0, ih = ihead; i < inohsz; i++, ih++) {
                mutex_enter(&ih_lock[i]);
                for (ip = ih->ih_chain[0];
                    ip != (struct inode *)ih;
                    ip = ip->i_forw) {
                        /*
                         * if inode is busy/modified/deleted, filesystem is busy
                         */
                        if (ip->i_ufsvfs != ufsvfsp)
                                continue;
                        if ((ip->i_flag & (IMOD | IUPD | ICHG)) ||
                            (RW_ISWRITER(&ip->i_rwlock)))
                                isbusy = 1;
                        if ((ip->i_nlink <= 0) && (ip->i_flag & IREF))
                                isreclaim = 1;
                        if (isbusy && (isreclaim || isnottrans))
                                break;
                }
                mutex_exit(&ih_lock[i]);
                if (isbusy && (isreclaim || isnottrans))
                        break;
        }
        *isbusyp = isbusy;
        *isreclaimp = isreclaim;
}

/*
 * As part of the ufs 'sync' operation, this routine is called to mark
 * the filesystem as STABLE if there is no modified metadata in memory.
 */
void
ufs_checkclean(struct vfs *vfsp)
{
        struct ufsvfs   *ufsvfsp        = (struct ufsvfs *)vfsp->vfs_data;
        struct fs       *fs             = ufsvfsp->vfs_fs;
        int             isbusy;
        int             isreclaim;
        int             updatesb;

        ASSERT(vfs_lock_held(vfsp));

        /*
         * filesystem is stable or cleanflag processing is disabled; do nothing
         *      no transitions when panic'ing
         */
        if (fs->fs_ronly ||
            fs->fs_clean == FSBAD ||
            fs->fs_clean == FSSUSPEND ||
            fs->fs_clean == FSSTABLE ||
            panicstr)
                return;

        /*
         * if logging and nothing to reclaim; do nothing
         */
        if ((fs->fs_clean == FSLOG) &&
            (((fs->fs_reclaim & FS_RECLAIM) == 0) ||
            (fs->fs_reclaim & FS_RECLAIMING)))
                return;

        /*
         * FS_CHECKCLEAN is reset if the file system goes dirty
         * FS_CHECKRECLAIM is reset if a file gets deleted
         */
        mutex_enter(&ufsvfsp->vfs_lock);
        fs->fs_reclaim |= (FS_CHECKCLEAN | FS_CHECKRECLAIM);
        mutex_exit(&ufsvfsp->vfs_lock);

        updatesb = 0;

        /*
         * if logging or buffers are busy; do nothing
         */
        isbusy = isreclaim = 0;
        if ((fs->fs_clean == FSLOG) ||
            (bcheck(vfsp->vfs_dev, ufsvfsp->vfs_bufp)))
                isbusy = 1;

        /*
         * isreclaim == TRUE means can't change the state of fs_reclaim
         */
        isreclaim =
            ((fs->fs_clean == FSLOG) &&
            (((fs->fs_reclaim & FS_RECLAIM) == 0) ||
            (fs->fs_reclaim & FS_RECLAIMING)));

        /*
         * if fs is busy or can't change the state of fs_reclaim; do nothing
         */
        if (isbusy && isreclaim)
                return;

        /*
         * look for busy or deleted inodes; (deleted == needs reclaim)
         */
        ufs_icheck(ufsvfsp, &isbusy, &isreclaim);

        mutex_enter(&ufsvfsp->vfs_lock);

        /*
         * IF POSSIBLE, RESET RECLAIM
         */
        /*
         * the reclaim thread is not running
         */
        if ((fs->fs_reclaim & FS_RECLAIMING) == 0)
                /*
                 * no files were deleted during the scan
                 */
                if (fs->fs_reclaim & FS_CHECKRECLAIM)
                        /*
                         * no deleted files were found in the inode cache
                         */
                        if ((isreclaim == 0) && (fs->fs_reclaim & FS_RECLAIM)) {
                                fs->fs_reclaim &= ~FS_RECLAIM;
                                updatesb = 1;
                        }
        /*
         * IF POSSIBLE, SET STABLE
         */
        /*
         * not logging
         */
        if (fs->fs_clean != FSLOG)
                /*
                 * file system has not gone dirty since the scan began
                 */
                if (fs->fs_reclaim & FS_CHECKCLEAN)
                        /*
                         * nothing dirty was found in the buffer or inode cache
                         */
                        if ((isbusy == 0) && (isreclaim == 0) &&
                            (fs->fs_clean != FSSTABLE)) {
                                fs->fs_clean = FSSTABLE;
                                updatesb = 1;
                        }

        mutex_exit(&ufsvfsp->vfs_lock);
        if (updatesb) {
                TRANS_SBWRITE(ufsvfsp, TOP_SBWRITE_STABLE);
        }
}

/*
 * called whenever an unlink occurs
 */
void
ufs_setreclaim(struct inode *ip)
{
        struct ufsvfs   *ufsvfsp        = ip->i_ufsvfs;
        struct fs       *fs             = ufsvfsp->vfs_fs;

        if (ip->i_nlink || fs->fs_ronly || (fs->fs_clean != FSLOG))
                return;

        /*
         * reclaim-needed bit is already set or we need to tell
         * ufs_checkclean that a file has been deleted
         */
        if ((fs->fs_reclaim & (FS_RECLAIM | FS_CHECKRECLAIM)) == FS_RECLAIM)
                return;

        mutex_enter(&ufsvfsp->vfs_lock);
        /*
         * inform ufs_checkclean that the file system has gone dirty
         */
        fs->fs_reclaim &= ~FS_CHECKRECLAIM;

        /*
         * set the reclaim-needed bit
         */
        if ((fs->fs_reclaim & FS_RECLAIM) == 0) {
                fs->fs_reclaim |= FS_RECLAIM;
                ufs_sbwrite(ufsvfsp);
        }
        mutex_exit(&ufsvfsp->vfs_lock);
}

/*
 * Before any modified metadata written back to the disk, this routine
 * is called to mark the filesystem as ACTIVE.
 */
void
ufs_notclean(struct ufsvfs *ufsvfsp)
{
        struct fs *fs = ufsvfsp->vfs_fs;

        ASSERT(MUTEX_HELD(&ufsvfsp->vfs_lock));
        ULOCKFS_SET_MOD((&ufsvfsp->vfs_ulockfs));

        /*
         * inform ufs_checkclean that the file system has gone dirty
         */
        fs->fs_reclaim &= ~FS_CHECKCLEAN;

        /*
         * ignore if active or bad or suspended or readonly or logging
         */
        if ((fs->fs_clean == FSACTIVE) || (fs->fs_clean == FSLOG) ||
            (fs->fs_clean == FSBAD) || (fs->fs_clean == FSSUSPEND) ||
            (fs->fs_ronly)) {
                mutex_exit(&ufsvfsp->vfs_lock);
                return;
        }
        fs->fs_clean = FSACTIVE;
        /*
         * write superblock synchronously
         */
        ufs_sbwrite(ufsvfsp);
        mutex_exit(&ufsvfsp->vfs_lock);
}

/*
 * ufs specific fbwrite()
 */
int
ufs_fbwrite(struct fbuf *fbp, struct inode *ip)
{
        struct ufsvfs   *ufsvfsp        = ip->i_ufsvfs;

        if (TRANS_ISTRANS(ufsvfsp))
                return (fbwrite(fbp));
        mutex_enter(&ufsvfsp->vfs_lock);
        ufs_notclean(ufsvfsp);
        return ((ufsvfsp->vfs_dio) ? fbdwrite(fbp) : fbwrite(fbp));
}

/*
 * ufs specific fbiwrite()
 */
int
ufs_fbiwrite(struct fbuf *fbp, struct inode *ip, daddr_t bn, long bsize)
{
        struct ufsvfs   *ufsvfsp        = ip->i_ufsvfs;
        o_mode_t        ifmt            = ip->i_mode & IFMT;
        buf_t           *bp;
        int             error;

        mutex_enter(&ufsvfsp->vfs_lock);
        ufs_notclean(ufsvfsp);
        if (ifmt == IFDIR || ifmt == IFSHAD || ifmt == IFATTRDIR ||
            (ip->i_ufsvfs->vfs_qinod == ip)) {
                TRANS_DELTA(ufsvfsp, ldbtob(bn * (offset_t)(btod(bsize))),
                    fbp->fb_count, DT_FBI, 0, 0);
        }
        /*
         * Inlined version of fbiwrite()
         */
        bp = pageio_setup((struct page *)NULL, fbp->fb_count,
            ip->i_devvp, B_WRITE);
        bp->b_flags &= ~B_PAGEIO;
        bp->b_un.b_addr = fbp->fb_addr;

        bp->b_blkno = bn * btod(bsize);
        bp->b_dev = cmpdev(ip->i_dev);  /* store in old dev format */
        bp->b_edev = ip->i_dev;
        bp->b_proc = NULL;                      /* i.e. the kernel */
        bp->b_file = ip->i_vnode;
        bp->b_offset = -1;

        if (ufsvfsp->vfs_log) {
                lufs_write_strategy(ufsvfsp->vfs_log, bp);
        } else if (ufsvfsp->vfs_snapshot) {
                fssnap_strategy(&ufsvfsp->vfs_snapshot, bp);
        } else {
                ufsvfsp->vfs_iotstamp = ddi_get_lbolt();
                ub.ub_fbiwrites.value.ul++;
                (void) bdev_strategy(bp);
                lwp_stat_update(LWP_STAT_OUBLK, 1);
        }
        error = biowait(bp);
        pageio_done(bp);
        fbrelse(fbp, S_OTHER);
        return (error);
}

/*
 * Write the ufs superblock only.
 */
void
ufs_sbwrite(struct ufsvfs *ufsvfsp)
{
        char sav_fs_fmod;
        struct fs *fs = ufsvfsp->vfs_fs;
        struct buf *bp = ufsvfsp->vfs_bufp;

        ASSERT(MUTEX_HELD(&ufsvfsp->vfs_lock));

        /*
         * for ulockfs processing, limit the superblock writes
         */
        if ((ufsvfsp->vfs_ulockfs.ul_sbowner) &&
            (curthread != ufsvfsp->vfs_ulockfs.ul_sbowner)) {
                /* try again later */
                fs->fs_fmod = 1;
                return;
        }

        ULOCKFS_SET_MOD((&ufsvfsp->vfs_ulockfs));
        /*
         * update superblock timestamp and fs_clean checksum
         * if marked FSBAD, we always want an erroneous
         * checksum to force repair
         */
        fs->fs_time = gethrestime_sec();
        fs->fs_state = (fs->fs_clean != FSBAD) ?
            FSOKAY - fs->fs_time : -(FSOKAY - fs->fs_time);
        switch (fs->fs_clean) {
        case FSCLEAN:
        case FSSTABLE:
                fs->fs_reclaim &= ~FS_RECLAIM;
                break;
        case FSACTIVE:
        case FSSUSPEND:
        case FSBAD:
        case FSLOG:
                break;
        default:
                fs->fs_clean = FSACTIVE;
                break;
        }
        /*
         * reset incore only bits
         */
        fs->fs_reclaim &= ~(FS_CHECKCLEAN | FS_CHECKRECLAIM);

        /*
         * delta the whole superblock
         */
        TRANS_DELTA(ufsvfsp, ldbtob(SBLOCK), sizeof (struct fs),
            DT_SB, NULL, 0);
        /*
         * retain the incore state of fs_fmod; set the ondisk state to 0
         */
        sav_fs_fmod = fs->fs_fmod;
        fs->fs_fmod = 0;

        /*
         * Don't release the buffer after written to the disk
         */
        UFS_BWRITE2(ufsvfsp, bp);
        fs->fs_fmod = sav_fs_fmod;      /* reset fs_fmod's incore state */
}

/*
 * Returns vfs pointer if vfs still being mounted. vfs lock is held.
 * Otherwise, returns NULL.
 *
 * For our purposes, "still mounted" means that the file system still appears
 * on the list of UFS file system instances.
 */
static vfs_t *
still_mounted(struct check_node *checkp)
{
        struct vfs      *vfsp;
        struct ufsvfs   *ufsp;

        mutex_enter(&ufsvfs_mutex);
        for (ufsp = ufs_instances; ufsp != NULL; ufsp = ufsp->vfs_next) {
                if (ufsp != checkp->ufsvfs)
                        continue;
                /*
                 * Tentative match:  verify it and try to lock.  (It's not at
                 * all clear how the verification could fail, given that we've
                 * gotten this far.  We would have had to reallocate the
                 * ufsvfs struct at hand for a new incarnation; is that really
                 * possible in the interval from constructing the check_node
                 * to here?)
                 */
                vfsp = ufsp->vfs_vfs;
                if (vfsp != checkp->vfsp)
                        continue;
                if (vfsp->vfs_dev != checkp->vfs_dev)
                        continue;
                if (vfs_lock(vfsp) != 0)
                        continue;

                mutex_exit(&ufsvfs_mutex);
                return (vfsp);
        }
        mutex_exit(&ufsvfs_mutex);
        return (NULL);
}

int
ufs_si_io_done(struct buf *bp)
{
        sema_v(&bp->b_io);
        return (0);
}

#define SI_BUFSZ roundup(sizeof (struct cg), DEV_BSIZE)
#define NSIBUF 32

/*
 * ufs_construct_si()
 * Read each cylinder group in turn and construct the summary information
 */
static int
ufs_construct_si(dev_t dev, struct fs *fs, struct ufsvfs *ufsvfsp)
{
        buf_t *bps, *bp;
        char *bufs;
        struct csum *sip = fs->fs_u.fs_csp;
        struct cg *cgp;
        int i, ncg;
        int error = 0, cg = 0;

        bps = kmem_alloc(NSIBUF * sizeof (buf_t), KM_SLEEP);
        bufs = kmem_alloc(NSIBUF * SI_BUFSZ, KM_SLEEP);

        /*
         * Initialise the buffer headers
         */
        for (bp = bps, i = 0; i < NSIBUF; i++, bp++) {
                bioinit(bp);
                bp->b_iodone = ufs_si_io_done;
                bp->b_bufsize = bp->b_bcount = SI_BUFSZ;
                bp->b_flags = B_READ;
                bp->b_un.b_addr = bufs + (i * SI_BUFSZ);
                bp->b_edev = dev;
        }

        /*
         * Repeat while there are cylinder groups left to read.
         */
        do {
                /*
                 * Issue upto NSIBUF asynchronous reads
                 */
                ncg = MIN(NSIBUF, (fs->fs_ncg - cg));
                for (bp = bps, i = 0; i < ncg; i++, bp++) {
                        bp->b_blkno = (daddr_t)fsbtodb(fs, cgtod(fs, cg + i));
                        if (ufsvfsp->vfs_log) {
                                lufs_read_strategy(ufsvfsp->vfs_log, bp);
                        } else {
                                (void) bdev_strategy(bp);
                        }
                }

                /*
                 * wait for each read to finish;
                 * check for errors and copy the csum info
                 */
                for (bp = bps, i = 0; i < ncg; i++, bp++) {
                        sema_p(&bp->b_io);
                        if (!error) {
                                cgp = bp->b_un.b_cg;
                                sip[cg + i] = cgp->cg_cs;
                                error = geterror(bp);
                        }
                }
                if (error) {
                        goto err;
                }
                cg += ncg;
        } while (cg < fs->fs_ncg);

err:
        kmem_free(bps, NSIBUF * sizeof (buf_t));
        kmem_free(bufs, NSIBUF * SI_BUFSZ);
        return (error);
}

/*
 * ufs_getsummaryinfo
 */
int
ufs_getsummaryinfo(dev_t dev, struct ufsvfs *ufsvfsp, struct fs *fs)
{
        int             i;              /* `for' loop counter */
        ssize_t         size;           /* bytes of summary info to read */
        daddr_t         frags;          /* frags of summary info to read */
        caddr_t         sip;            /* summary info */
        struct buf      *tp;            /* tmp buf */

        /*
         * maintain metadata map for trans device (debug only)
         */
        TRANS_MATA_SI(ufsvfsp, fs);

        /*
         * Compute #frags and allocate space for summary info
         */
        frags = howmany(fs->fs_cssize, fs->fs_fsize);
        sip = kmem_alloc((size_t)fs->fs_cssize, KM_SLEEP);
        fs->fs_u.fs_csp = (struct csum *)sip;

        if (fs->fs_si == FS_SI_BAD) {
                /*
                 * The summary information is unknown, read it in from
                 * the cylinder groups.
                 */
                if (TRANS_ISTRANS(ufsvfsp) && !TRANS_ISERROR(ufsvfsp) &&
                    ufsvfsp->vfs_log->un_logmap) {
                        logmap_roll_dev(ufsvfsp->vfs_log); /* flush the log */
                }
                bzero(sip, (size_t)fs->fs_cssize);
                if (ufs_construct_si(dev, fs, ufsvfsp)) {
                        kmem_free(fs->fs_u.fs_csp, fs->fs_cssize);
                        fs->fs_u.fs_csp = NULL;
                        return (EIO);
                }
        } else {
                /* Read summary info a fs block at a time */
                size = fs->fs_bsize;
                for (i = 0; i < frags; i += fs->fs_frag) {
                        if (i + fs->fs_frag > frags)
                                /*
                                 * This happens only the last iteration, so
                                 * don't worry about size being reset
                                 */
                                size = (frags - i) * fs->fs_fsize;
                        tp = UFS_BREAD(ufsvfsp, dev,
                            (daddr_t)fsbtodb(fs, fs->fs_csaddr+i), size);
                        tp->b_flags |= B_STALE | B_AGE;
                        if (tp->b_flags & B_ERROR) {
                                kmem_free(fs->fs_u.fs_csp, fs->fs_cssize);
                                fs->fs_u.fs_csp = NULL;
                                brelse(tp);
                                return (EIO);
                        }
                        bcopy(tp->b_un.b_addr, sip, size);
                        sip += size;
                        brelse(tp);
                }
        }
        bzero((caddr_t)&fs->fs_cstotal, sizeof (fs->fs_cstotal));
        for (i = 0; i < fs->fs_ncg; ++i) {
                fs->fs_cstotal.cs_ndir += fs->fs_cs(fs, i).cs_ndir;
                fs->fs_cstotal.cs_nbfree += fs->fs_cs(fs, i).cs_nbfree;
                fs->fs_cstotal.cs_nifree += fs->fs_cs(fs, i).cs_nifree;
                fs->fs_cstotal.cs_nffree += fs->fs_cs(fs, i).cs_nffree;
        }
        return (0);
}

/*
 * ufs_putsummaryinfo() stores all the cylinder group summary information
 * This is only used when logging, but the file system may not
 * be logging at the time, eg a read-only mount to flush the log
 * may push the summary info out.
 */
int
ufs_putsummaryinfo(dev_t dev, struct ufsvfs *ufsvfsp, struct fs *fs)
{
        struct buf      b, *bp;         /* tmp buf */
        caddr_t         sip;            /* summary info */
        ssize_t         size;           /* bytes of summary info to write */
        daddr_t         frags;          /* frags of summary info to write */
        int             i;              /* `for' loop counter */
        int             error;          /* error */

        if (TRANS_ISERROR(ufsvfsp)) {
                return (EIO);
        }

        if ((fs->fs_si != FS_SI_BAD) || !ufsvfsp->vfs_nolog_si) {
                return (0);
        }

        bp = &b;
        bioinit(bp);
        bp->b_iodone = ufs_si_io_done;
        bp->b_bufsize = size = fs->fs_bsize;
        bp->b_flags = B_WRITE;
        bp->b_un.b_addr = kmem_alloc(size, KM_SLEEP);
        bp->b_edev = dev;
        frags = howmany(fs->fs_cssize, fs->fs_fsize);
        sip = (caddr_t)fs->fs_u.fs_csp;

        /* Write summary info one fs block at a time */
        for (error = 0, i = 0; (i < frags) && (error == 0); i += fs->fs_frag) {
                if (i + fs->fs_frag > frags) {
                        /*
                         * This happens only the last iteration, so
                         * don't worry about size being reset
                         */
                        size = (frags - i) * fs->fs_fsize;
                }
                bcopy(sip, bp->b_un.b_addr, size);
                bp->b_blkno = (daddr_t)fsbtodb(fs, fs->fs_csaddr+i);
                bp->b_bcount = size;
                (void) bdev_strategy(bp);
                sema_p(&bp->b_io); /* wait for write to complete */
                error = geterror(bp);
                sip += size;
        }
        kmem_free(bp->b_un.b_addr, fs->fs_bsize);
        if (!error) {
                fs->fs_si = FS_SI_OK;
        }
        return (error);
}

/*
 * Decide whether it is okay to remove within a sticky directory.
 * Two conditions need to be met:  write access to the directory
 * is needed.  In sticky directories, write access is not sufficient;
 * you can remove entries from a directory only if you own the directory,
 * if you are privileged, if you own the entry or if the entry is
 * a plain file and you have write access to that file.
 * Function returns 0 if remove access is granted.
 * Note, the caller is responsible for holding the i_contents lock
 * at least as reader on the inquired inode 'ip'.
 */
int
ufs_sticky_remove_access(struct inode *dp, struct inode *ip, struct cred *cr)
{
        uid_t uid;

        ASSERT(RW_LOCK_HELD(&ip->i_contents));

        if ((dp->i_mode & ISVTX) &&
            (uid = crgetuid(cr)) != dp->i_uid &&
            uid != ip->i_uid &&
            ((ip->i_mode & IFMT) != IFREG ||
            ufs_iaccess(ip, IWRITE, cr, 0) != 0))
                return (secpolicy_vnode_remove(cr));

        return (0);
}
#endif  /* _KERNEL */

extern  int around[9];
extern  int inside[9];
extern  uchar_t *fragtbl[];

/*
 * Update the frsum fields to reflect addition or deletion
 * of some frags.
 */
void
fragacct(struct fs *fs, int fragmap, int32_t *fraglist, int cnt)
{
        int inblk;
        int field, subfield;
        int siz, pos;

        /*
         * ufsvfsp->vfs_lock is held when calling this.
         */
        inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1;
        fragmap <<= 1;
        for (siz = 1; siz < fs->fs_frag; siz++) {
                if ((inblk & (1 << (siz + (fs->fs_frag % NBBY)))) == 0)
                        continue;
                field = around[siz];
                subfield = inside[siz];
                for (pos = siz; pos <= fs->fs_frag; pos++) {
                        if ((fragmap & field) == subfield) {
                                fraglist[siz] += cnt;
                                ASSERT(fraglist[siz] >= 0);
                                pos += siz;
                                field <<= siz;
                                subfield <<= siz;
                        }
                        field <<= 1;
                        subfield <<= 1;
                }
        }
}

/*
 * Block operations
 */

/*
 * Check if a block is available
 */
int
isblock(struct fs *fs, uchar_t *cp, daddr_t h)
{
        uchar_t mask;

        ASSERT(fs->fs_frag == 8 || fs->fs_frag == 4 || fs->fs_frag == 2 || \
            fs->fs_frag == 1);
        /*
         * ufsvfsp->vfs_lock is held when calling this.
         */
        switch ((int)fs->fs_frag) {
        case 8:
                return (cp[h] == 0xff);
        case 4:
                mask = 0x0f << ((h & 0x1) << 2);
                return ((cp[h >> 1] & mask) == mask);
        case 2:
                mask = 0x03 << ((h & 0x3) << 1);
                return ((cp[h >> 2] & mask) == mask);
        case 1:
                mask = 0x01 << (h & 0x7);
                return ((cp[h >> 3] & mask) == mask);
        default:
#ifndef _KERNEL
                cmn_err(CE_PANIC, "isblock: illegal fs->fs_frag value (%d)",
                    fs->fs_frag);
#endif /* _KERNEL */
                return (0);
        }
}

/*
 * Take a block out of the map
 */
void
clrblock(struct fs *fs, uchar_t *cp, daddr_t h)
{
        ASSERT(fs->fs_frag == 8 || fs->fs_frag == 4 || fs->fs_frag == 2 || \
            fs->fs_frag == 1);
        /*
         * ufsvfsp->vfs_lock is held when calling this.
         */
        switch ((int)fs->fs_frag) {
        case 8:
                cp[h] = 0;
                return;
        case 4:
                cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2));
                return;
        case 2:
                cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1));
                return;
        case 1:
                cp[h >> 3] &= ~(0x01 << (h & 0x7));
                return;
        default:
#ifndef _KERNEL
                cmn_err(CE_PANIC, "clrblock: illegal fs->fs_frag value (%d)",
                    fs->fs_frag);
#endif /* _KERNEL */
                return;
        }
}

/*
 * Is block allocated?
 */
int
isclrblock(struct fs *fs, uchar_t *cp, daddr_t h)
{
        uchar_t mask;
        int     frag;
        /*
         * ufsvfsp->vfs_lock is held when calling this.
         */
        frag = fs->fs_frag;
        ASSERT(frag == 8 || frag == 4 || frag == 2 || frag == 1);
        switch (frag) {
        case 8:
                return (cp[h] == 0);
        case 4:
                mask = ~(0x0f << ((h & 0x1) << 2));
                return (cp[h >> 1] == (cp[h >> 1] & mask));
        case 2:
                mask =  ~(0x03 << ((h & 0x3) << 1));
                return (cp[h >> 2] == (cp[h >> 2] & mask));
        case 1:
                mask = ~(0x01 << (h & 0x7));
                return (cp[h >> 3] == (cp[h >> 3] & mask));
        default:
#ifndef _KERNEL
                cmn_err(CE_PANIC, "isclrblock: illegal fs->fs_frag value (%d)",
                    fs->fs_frag);
#endif /* _KERNEL */
                break;
        }
        return (0);
}

/*
 * Put a block into the map
 */
void
setblock(struct fs *fs, uchar_t *cp, daddr_t h)
{
        ASSERT(fs->fs_frag == 8 || fs->fs_frag == 4 || fs->fs_frag == 2 || \
            fs->fs_frag == 1);
        /*
         * ufsvfsp->vfs_lock is held when calling this.
         */
        switch ((int)fs->fs_frag) {
        case 8:
                cp[h] = 0xff;
                return;
        case 4:
                cp[h >> 1] |= (0x0f << ((h & 0x1) << 2));
                return;
        case 2:
                cp[h >> 2] |= (0x03 << ((h & 0x3) << 1));
                return;
        case 1:
                cp[h >> 3] |= (0x01 << (h & 0x7));
                return;
        default:
#ifndef _KERNEL
                cmn_err(CE_PANIC, "setblock: illegal fs->fs_frag value (%d)",
                    fs->fs_frag);
#endif /* _KERNEL */
                return;
        }
}

int
skpc(char c, uint_t len, char *cp)
{
        if (len == 0)
                return (0);
        while (*cp++ == c && --len)
                ;
        return (len);
}