/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1986, 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#include "opt_ufs.h"
#include "opt_quota.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/racct.h>
#include <sys/random.h>
#include <sys/resourcevar.h>
#include <sys/rwlock.h>
#include <sys/stat.h>
#include <sys/vmmeter.h>
#include <sys/vnode.h>

#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_object.h>

#include <ufs/ufs/extattr.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/dir.h>
#ifdef UFS_DIRHASH
#include <ufs/ufs/dirhash.h>
#endif
#include <ufs/ufs/ufs_extern.h>

#include <ufs/ffs/fs.h>
#include <ufs/ffs/ffs_extern.h>

static int ffs_indirtrunc(struct inode *, ufs2_daddr_t, ufs2_daddr_t,
            ufs2_daddr_t, int, ufs2_daddr_t *);

static void
ffs_inode_bwrite(struct vnode *vp, struct buf *bp, int flags)
{
        if ((flags & IO_SYNC) != 0)
                bwrite(bp);
        else if (DOINGASYNC(vp))
                bdwrite(bp);
        else
                bawrite(bp);
}

/*
 * Update the access, modified, and inode change times as specified by the
 * IN_ACCESS, IN_UPDATE, and IN_CHANGE flags respectively.  Write the inode
 * to disk if the IN_MODIFIED flag is set (it may be set initially, or by
 * the timestamp update).  The IN_LAZYMOD flag is set to force a write
 * later if not now.  The IN_LAZYACCESS is set instead of IN_MODIFIED if the fs
 * is currently being suspended (or is suspended) and vnode has been accessed.
 * If we write now, then clear IN_MODIFIED, IN_LAZYACCESS and IN_LAZYMOD to
 * reflect the presumably successful write, and if waitfor is set, then wait
 * for the write to complete.
 */
int
ffs_update(struct vnode *vp, int waitfor)
{
        struct fs *fs;
        struct buf *bp;
        struct inode *ip;
        daddr_t bn;
        int flags, error;

        ASSERT_VOP_ELOCKED(vp, "ffs_update");
        ufs_itimes(vp);
        ip = VTOI(vp);
        if ((ip->i_flag & IN_MODIFIED) == 0 && waitfor == 0)
                return (0);
        ip->i_flag &= ~(IN_LAZYACCESS | IN_LAZYMOD | IN_MODIFIED);
        /*
         * The IN_SIZEMOD and IN_IBLKDATA flags indicate changes to the
         * file size and block pointer fields in the inode. When these
         * fields have been changed, the fsync() and fsyncdata() system 
         * calls must write the inode to ensure their semantics that the 
         * file is on stable store.
         *
         * The IN_SIZEMOD and IN_IBLKDATA flags cannot be cleared until
         * a synchronous write of the inode is done. If they are cleared
         * on an asynchronous write, then the inode may not yet have been
         * written to the disk when an fsync() or fsyncdata() call is done.
         * Absent these flags, these calls would not know that they needed
         * to write the inode. Thus, these flags only can be cleared on
         * synchronous writes of the inode. Since the inode will be locked
         * for the duration of the I/O that writes it to disk, no fsync()
         * or fsyncdata() will be able to run before the on-disk inode
         * is complete.
         */
        if (waitfor)
                ip->i_flag &= ~(IN_SIZEMOD | IN_IBLKDATA);
        fs = ITOFS(ip);
        if (fs->fs_ronly)
                return (0);
        /*
         * If we are updating a snapshot and another process is currently
         * writing the buffer containing the inode for this snapshot then
         * a deadlock can occur when it tries to check the snapshot to see
         * if that block needs to be copied. Thus when updating a snapshot
         * we check to see if the buffer is already locked, and if it is
         * we drop the snapshot lock until the buffer has been written
         * and is available to us. We have to grab a reference to the
         * snapshot vnode to prevent it from being removed while we are
         * waiting for the buffer.
         */
loop:
        flags = 0;
        if (IS_SNAPSHOT(ip))
                flags = GB_LOCK_NOWAIT;
        bn = fsbtodb(fs, ino_to_fsba(fs, ip->i_number));
        error = ffs_breadz(VFSTOUFS(vp->v_mount), ITODEVVP(ip), bn, bn,
             (int) fs->fs_bsize, NULL, NULL, 0, NOCRED, flags, NULL, &bp);
        if (error != 0) {
                /*
                 * If EBUSY was returned without GB_LOCK_NOWAIT (which
                 * requests trylock for buffer lock), it is for some
                 * other reason and we should not handle it specially.
                 */
                if (error != EBUSY || (flags & GB_LOCK_NOWAIT) == 0)
                        return (error);

                /*
                 * Wait for our inode block to become available.
                 *
                 * Hold a reference to the vnode to protect against
                 * ffs_snapgone(). Since we hold a reference, it can only
                 * get reclaimed (VIRF_DOOMED flag) in a forcible downgrade
                 * or unmount. For an unmount, the entire filesystem will be
                 * gone, so we cannot attempt to touch anything associated
                 * with it while the vnode is unlocked; all we can do is 
                 * pause briefly and try again. If when we relock the vnode
                 * we discover that it has been reclaimed, updating it is no
                 * longer necessary and we can just return an error.
                 */
                vref(vp);
                VOP_UNLOCK(vp);
                pause("ffsupd", 1);
                vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
                vrele(vp);
                if (!IS_UFS(vp))
                        return (ENOENT);

                /*
                 * Recalculate flags, because the vnode was relocked and
                 * could no longer be a snapshot.
                 */
                goto loop;
        }
        if (DOINGSOFTDEP(vp))
                softdep_update_inodeblock(ip, bp, waitfor);
        else if (ip->i_effnlink != ip->i_nlink)
                panic("ffs_update: bad link cnt");
        if (I_IS_UFS1(ip)) {
                *((struct ufs1_dinode *)bp->b_data +
                    ino_to_fsbo(fs, ip->i_number)) = *ip->i_din1;
                /*
                 * XXX: FIX? The entropy here is desirable,
                 * but the harvesting may be expensive
                 */
                random_harvest_queue(&(ip->i_din1), sizeof(ip->i_din1), RANDOM_FS_ATIME);
        } else {
                ffs_update_dinode_ckhash(fs, ip->i_din2);
                *((struct ufs2_dinode *)bp->b_data +
                    ino_to_fsbo(fs, ip->i_number)) = *ip->i_din2;
                /*
                 * XXX: FIX? The entropy here is desirable,
                 * but the harvesting may be expensive
                 */
                random_harvest_queue(&(ip->i_din2), sizeof(ip->i_din2), RANDOM_FS_ATIME);
        }
        if (waitfor) {
                error = bwrite(bp);
                if (ffs_fsfail_cleanup(VFSTOUFS(vp->v_mount), error))
                        error = 0;
        } else if (vm_page_count_severe() || buf_dirty_count_severe()) {
                bawrite(bp);
                error = 0;
        } else {
                if (bp->b_bufsize == fs->fs_bsize)
                        bp->b_flags |= B_CLUSTEROK;
                bdwrite(bp);
                error = 0;
        }
        return (error);
}

#define SINGLE  0       /* index of single indirect block */
#define DOUBLE  1       /* index of double indirect block */
#define TRIPLE  2       /* index of triple indirect block */
/*
 * Truncate the inode ip to at most length size, freeing the
 * disk blocks.
 */
int
ffs_truncate(struct vnode *vp,
        off_t length,
        int flags,
        struct ucred *cred)
{
        struct inode *ip;
        ufs2_daddr_t bn, lbn, lastblock, lastiblock[UFS_NIADDR];
        ufs2_daddr_t indir_lbn[UFS_NIADDR], oldblks[UFS_NDADDR + UFS_NIADDR];
#ifdef INVARIANTS
        ufs2_daddr_t newblks[UFS_NDADDR + UFS_NIADDR];
#endif
        ufs2_daddr_t count, blocksreleased = 0, blkno;
        struct bufobj *bo __diagused;
        struct fs *fs;
        struct buf *bp;
        struct ufsmount *ump;
        int softdeptrunc, journaltrunc;
        int needextclean, extblocks;
        int offset, size, level, nblocks;
        int i, error, allerror, indiroff, waitforupdate;
        uint64_t key;
        off_t osize;

        ip = VTOI(vp);
        ump = VFSTOUFS(vp->v_mount);
        fs = ump->um_fs;
        bo = &vp->v_bufobj;

        ASSERT_VOP_LOCKED(vp, "ffs_truncate");

        if (length < 0)
                return (EINVAL);
        if (length > fs->fs_maxfilesize)
                return (EFBIG);
#ifdef QUOTA
        error = getinoquota(ip);
        if (error)
                return (error);
#endif
        /*
         * Historically clients did not have to specify which data
         * they were truncating. So, if not specified, we assume
         * traditional behavior, e.g., just the normal data.
         */
        if ((flags & (IO_EXT | IO_NORMAL)) == 0)
                flags |= IO_NORMAL;
        if (!DOINGSOFTDEP(vp) && !DOINGASYNC(vp))
                flags |= IO_SYNC;
        waitforupdate = (flags & IO_SYNC) != 0 || !DOINGASYNC(vp);
        /*
         * If we are truncating the extended-attributes, and cannot
         * do it with soft updates, then do it slowly here. If we are
         * truncating both the extended attributes and the file contents
         * (e.g., the file is being unlinked), then pick it off with
         * soft updates below.
         */
        allerror = 0;
        needextclean = 0;
        softdeptrunc = 0;
        journaltrunc = DOINGSUJ(vp);
        journaltrunc = 0;       /* XXX temp patch until bug found */
        if (journaltrunc == 0 && DOINGSOFTDEP(vp) && length == 0)
                softdeptrunc = !softdep_slowdown(vp);
        extblocks = 0;
        if (fs->fs_magic == FS_UFS2_MAGIC && ip->i_din2->di_extsize > 0) {
                extblocks = btodb(fragroundup(fs, ip->i_din2->di_extsize));
        }
        if ((flags & IO_EXT) && extblocks > 0) {
                if (length != 0)
                        panic("ffs_truncate: partial trunc of extdata");
                if (softdeptrunc || journaltrunc) {
                        if ((flags & IO_NORMAL) == 0)
                                goto extclean;
                        needextclean = 1;
                } else {
                        if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
                                return (error);
#ifdef QUOTA
                        (void) chkdq(ip, -extblocks, NOCRED, FORCE);
#endif
                        vinvalbuf(vp, V_ALT, 0, 0);
                        vn_pages_remove(vp,
                            OFF_TO_IDX(lblktosize(fs, -extblocks)), 0);
                        osize = ip->i_din2->di_extsize;
                        ip->i_din2->di_blocks -= extblocks;
                        ip->i_din2->di_extsize = 0;
                        for (i = 0; i < UFS_NXADDR; i++) {
                                oldblks[i] = ip->i_din2->di_extb[i];
                                ip->i_din2->di_extb[i] = 0;
                        }
                        UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE);
                        if ((error = ffs_update(vp, waitforupdate)))
                                return (error);
                        for (i = 0; i < UFS_NXADDR; i++) {
                                if (oldblks[i] == 0)
                                        continue;
                                ffs_blkfree(ump, fs, ITODEVVP(ip), oldblks[i],
                                    sblksize(fs, osize, i), ip->i_number,
                                    vp->v_type, NULL, SINGLETON_KEY);
                        }
                }
        }
        if ((flags & IO_NORMAL) == 0)
                return (0);
        if (vp->v_type == VLNK && ip->i_size < ump->um_maxsymlinklen) {
#ifdef INVARIANTS
                if (length != 0)
                        panic("ffs_truncate: partial truncate of symlink");
#endif
                bzero(DIP(ip, i_shortlink), (uint64_t)ip->i_size);
                ip->i_size = 0;
                DIP_SET(ip, i_size, 0);
                UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
                if (needextclean)
                        goto extclean;
                return (ffs_update(vp, waitforupdate));
        }
        if (ip->i_size == length) {
                UFS_INODE_SET_FLAG(ip, IN_CHANGE | IN_UPDATE);
                if (needextclean)
                        goto extclean;
                return (ffs_update(vp, 0));
        }
        if (fs->fs_ronly)
                panic("ffs_truncate: read-only filesystem");
        if (IS_SNAPSHOT(ip))
                ffs_snapremove(vp);
        cluster_init_vn(&ip->i_clusterw);
        osize = ip->i_size;
        /*
         * Lengthen the size of the file. We must ensure that the
         * last byte of the file is allocated. Since the smallest
         * value of osize is 0, length will be at least 1.
         */
        if (osize < length) {
                vnode_pager_setsize(vp, length);
                flags |= BA_CLRBUF;
                error = UFS_BALLOC(vp, length - 1, 1, cred, flags, &bp);
                if (error) {
                        vnode_pager_setsize(vp, osize);
                        return (error);
                }
                ip->i_size = length;
                DIP_SET(ip, i_size, length);
                if (bp->b_bufsize == fs->fs_bsize)
                        bp->b_flags |= B_CLUSTEROK;
                ffs_inode_bwrite(vp, bp, flags);
                UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
                return (ffs_update(vp, waitforupdate));
        }
        /*
         * Lookup block number for a given offset. Zero length files
         * have no blocks, so return a blkno of -1.
         */
        lbn = lblkno(fs, length - 1);
        if (length == 0) {
                blkno = -1;
        } else if (lbn < UFS_NDADDR) {
                blkno = DIP(ip, i_db[lbn]);
        } else {
                error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), fs->fs_bsize,
                    cred, BA_METAONLY, &bp);
                if (error)
                        return (error);
                indiroff = (lbn - UFS_NDADDR) % NINDIR(fs);
                if (I_IS_UFS1(ip))
                        blkno = ((ufs1_daddr_t *)(bp->b_data))[indiroff];
                else
                        blkno = ((ufs2_daddr_t *)(bp->b_data))[indiroff];
                /*
                 * If the block number is non-zero, then the indirect block
                 * must have been previously allocated and need not be written.
                 * If the block number is zero, then we may have allocated
                 * the indirect block and hence need to write it out.
                 */
                if (blkno != 0)
                        brelse(bp);
                else if (flags & IO_SYNC)
                        bwrite(bp);
                else
                        bdwrite(bp);
        }
        /*
         * If the block number at the new end of the file is zero,
         * then we must allocate it to ensure that the last block of 
         * the file is allocated. Soft updates does not handle this
         * case, so here we have to clean up the soft updates data
         * structures describing the allocation past the truncation
         * point. Finding and deallocating those structures is a lot of
         * work. Since partial truncation with a hole at the end occurs
         * rarely, we solve the problem by syncing the file so that it
         * will have no soft updates data structures left.
         */
        if (blkno == 0 && (error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
                return (error);
        if (blkno != 0 && DOINGSOFTDEP(vp)) {
                if (softdeptrunc == 0 && journaltrunc == 0) {
                        /*
                         * If soft updates cannot handle this truncation,
                         * clean up soft dependency data structures and
                         * fall through to the synchronous truncation.
                         */
                        if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
                                return (error);
                } else {
                        flags = IO_NORMAL | (needextclean ? IO_EXT: 0);
                        if (journaltrunc)
                                softdep_journal_freeblocks(ip, cred, length,
                                    flags);
                        else
                                softdep_setup_freeblocks(ip, length, flags);
                        ASSERT_VOP_LOCKED(vp, "ffs_truncate1");
                        if (journaltrunc == 0) {
                                UFS_INODE_SET_FLAG(ip, IN_CHANGE | IN_UPDATE);
                                error = ffs_update(vp, 0);
                        }
                        return (error);
                }
        }
        /*
         * Shorten the size of the file. If the last block of the
         * shortened file is unallocated, we must allocate it.
         * Additionally, if the file is not being truncated to a
         * block boundary, the contents of the partial block
         * following the end of the file must be zero'ed in
         * case it ever becomes accessible again because of
         * subsequent file growth. Directories however are not
         * zero'ed as they should grow back initialized to empty.
         */
        offset = blkoff(fs, length);
        if (blkno != 0 && offset == 0) {
                ip->i_size = length;
                DIP_SET(ip, i_size, length);
                UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
#ifdef UFS_DIRHASH
                if (vp->v_type == VDIR && ip->i_dirhash != NULL)
                        ufsdirhash_dirtrunc(ip, length);
#endif
        } else {
                lbn = lblkno(fs, length);
                flags |= BA_CLRBUF;
                error = UFS_BALLOC(vp, length - 1, 1, cred, flags, &bp);
                if (error)
                        return (error);
                ffs_inode_bwrite(vp, bp, flags);

                /*
                 * When we are doing soft updates and the UFS_BALLOC
                 * above fills in a direct block hole with a full sized
                 * block that will be truncated down to a fragment below,
                 * we must flush out the block dependency with an FSYNC
                 * so that we do not get a soft updates inconsistency
                 * when we create the fragment below.
                 */
                if (DOINGSOFTDEP(vp) && lbn < UFS_NDADDR &&
                    fragroundup(fs, blkoff(fs, length)) < fs->fs_bsize &&
                    (error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
                        return (error);

                error = UFS_BALLOC(vp, length - 1, 1, cred, flags, &bp);
                if (error)
                        return (error);
                ip->i_size = length;
                DIP_SET(ip, i_size, length);
#ifdef UFS_DIRHASH
                if (vp->v_type == VDIR && ip->i_dirhash != NULL)
                        ufsdirhash_dirtrunc(ip, length);
#endif
                size = blksize(fs, ip, lbn);
                if (vp->v_type != VDIR && offset != 0)
                        bzero((char *)bp->b_data + offset,
                            (uint64_t)(size - offset));
                /* Kirk's code has reallocbuf(bp, size, 1) here */
                allocbuf(bp, size);
                if (bp->b_bufsize == fs->fs_bsize)
                        bp->b_flags |= B_CLUSTEROK;
                ffs_inode_bwrite(vp, bp, flags);
                UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
        }
        /*
         * Calculate index into inode's block list of
         * last direct and indirect blocks (if any)
         * which we want to keep.  Lastblock is -1 when
         * the file is truncated to 0.
         */
        lastblock = lblkno(fs, length + fs->fs_bsize - 1) - 1;
        lastiblock[SINGLE] = lastblock - UFS_NDADDR;
        lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
        lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
        nblocks = btodb(fs->fs_bsize);
        /*
         * Update file and block pointers on disk before we start freeing
         * blocks.  If we crash before free'ing blocks below, the blocks
         * will be returned to the free list.  lastiblock values are also
         * normalized to -1 for calls to ffs_indirtrunc below.
         */
        for (level = TRIPLE; level >= SINGLE; level--) {
                oldblks[UFS_NDADDR + level] = DIP(ip, i_ib[level]);
                if (lastiblock[level] < 0) {
                        DIP_SET(ip, i_ib[level], 0);
                        lastiblock[level] = -1;
                }
        }
        for (i = 0; i < UFS_NDADDR; i++) {
                oldblks[i] = DIP(ip, i_db[i]);
                if (i > lastblock)
                        DIP_SET(ip, i_db[i], 0);
        }
        UFS_INODE_SET_FLAG(ip, IN_CHANGE | IN_UPDATE);
        allerror = ffs_update(vp, waitforupdate);

        /*
         * Having written the new inode to disk, save its new configuration
         * and put back the old block pointers long enough to process them.
         * Note that we save the new block configuration so we can check it
         * when we are done.
         */
        for (i = 0; i < UFS_NDADDR; i++) {
#ifdef INVARIANTS
                newblks[i] = DIP(ip, i_db[i]);
#endif
                DIP_SET(ip, i_db[i], oldblks[i]);
        }
        for (i = 0; i < UFS_NIADDR; i++) {
#ifdef INVARIANTS
                newblks[UFS_NDADDR + i] = DIP(ip, i_ib[i]);
#endif
                DIP_SET(ip, i_ib[i], oldblks[UFS_NDADDR + i]);
        }
        ip->i_size = osize;
        DIP_SET(ip, i_size, osize);
        UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);

        error = vtruncbuf(vp, length, fs->fs_bsize);
        if (error && (allerror == 0))
                allerror = error;

        /*
         * Indirect blocks first.
         */
        indir_lbn[SINGLE] = -UFS_NDADDR;
        indir_lbn[DOUBLE] = indir_lbn[SINGLE] - NINDIR(fs) - 1;
        indir_lbn[TRIPLE] = indir_lbn[DOUBLE] - NINDIR(fs) * NINDIR(fs) - 1;
        for (level = TRIPLE; level >= SINGLE; level--) {
                bn = DIP(ip, i_ib[level]);
                if (bn != 0) {
                        error = ffs_indirtrunc(ip, indir_lbn[level],
                            fsbtodb(fs, bn), lastiblock[level], level, &count);
                        if (error)
                                allerror = error;
                        blocksreleased += count;
                        if (lastiblock[level] < 0) {
                                DIP_SET(ip, i_ib[level], 0);
                                ffs_blkfree(ump, fs, ump->um_devvp, bn,
                                    fs->fs_bsize, ip->i_number,
                                    vp->v_type, NULL, SINGLETON_KEY);
                                blocksreleased += nblocks;
                        }
                }
                if (lastiblock[level] >= 0)
                        goto done;
        }

        /*
         * All whole direct blocks or frags.
         */
        key = ffs_blkrelease_start(ump, ump->um_devvp, ip->i_number);
        for (i = UFS_NDADDR - 1; i > lastblock; i--) {
                long bsize;

                bn = DIP(ip, i_db[i]);
                if (bn == 0)
                        continue;
                DIP_SET(ip, i_db[i], 0);
                bsize = blksize(fs, ip, i);
                ffs_blkfree(ump, fs, ump->um_devvp, bn, bsize, ip->i_number,
                    vp->v_type, NULL, key);
                blocksreleased += btodb(bsize);
        }
        ffs_blkrelease_finish(ump, key);
        if (lastblock < 0)
                goto done;

        /*
         * Finally, look for a change in size of the
         * last direct block; release any frags.
         */
        bn = DIP(ip, i_db[lastblock]);
        if (bn != 0) {
                long oldspace, newspace;

                /*
                 * Calculate amount of space we're giving
                 * back as old block size minus new block size.
                 */
                oldspace = blksize(fs, ip, lastblock);
                ip->i_size = length;
                DIP_SET(ip, i_size, length);
                UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
                newspace = blksize(fs, ip, lastblock);
                if (newspace == 0)
                        panic("ffs_truncate: newspace");
                if (oldspace - newspace > 0) {
                        /*
                         * Block number of space to be free'd is
                         * the old block # plus the number of frags
                         * required for the storage we're keeping.
                         */
                        bn += numfrags(fs, newspace);
                        ffs_blkfree(ump, fs, ump->um_devvp, bn,
                           oldspace - newspace, ip->i_number, vp->v_type,
                           NULL, SINGLETON_KEY);
                        blocksreleased += btodb(oldspace - newspace);
                }
        }
done:
#ifdef INVARIANTS
        for (level = SINGLE; level <= TRIPLE; level++)
                if (newblks[UFS_NDADDR + level] != DIP(ip, i_ib[level]))
                        panic("ffs_truncate1: level %d newblks %jd != i_ib %jd",
                            level, (intmax_t)newblks[UFS_NDADDR + level],
                            (intmax_t)DIP(ip, i_ib[level]));
        for (i = 0; i < UFS_NDADDR; i++)
                if (newblks[i] != DIP(ip, i_db[i]))
                        panic("ffs_truncate2: blkno %d newblks %jd != i_db %jd",
                            i, (intmax_t)newblks[i],
                            (intmax_t)DIP(ip, i_db[i]));
        BO_LOCK(bo);
        if (length == 0 &&
            (fs->fs_magic != FS_UFS2_MAGIC || ip->i_din2->di_extsize == 0) &&
            (bo->bo_dirty.bv_cnt > 0 || bo->bo_clean.bv_cnt > 0))
                panic("ffs_truncate3: vp = %p, buffers: dirty = %d, clean = %d",
                        vp, bo->bo_dirty.bv_cnt, bo->bo_clean.bv_cnt);
        BO_UNLOCK(bo);
#endif /* INVARIANTS */
        /*
         * Put back the real size.
         */
        ip->i_size = length;
        DIP_SET(ip, i_size, length);
        if (DIP(ip, i_blocks) >= blocksreleased)
                DIP_SET(ip, i_blocks, DIP(ip, i_blocks) - blocksreleased);
        else    /* sanity */
                DIP_SET(ip, i_blocks, 0);
        UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE);
#ifdef QUOTA
        (void) chkdq(ip, -blocksreleased, NOCRED, FORCE);
#endif
        return (allerror);

extclean:
        if (journaltrunc)
                softdep_journal_freeblocks(ip, cred, length, IO_EXT);
        else
                softdep_setup_freeblocks(ip, length, IO_EXT);
        return (ffs_update(vp, waitforupdate));
}

/*
 * Release blocks associated with the inode ip and stored in the indirect
 * block bn.  Blocks are free'd in LIFO order up to (but not including)
 * lastbn.  If level is greater than SINGLE, the block is an indirect block
 * and recursive calls to indirtrunc must be used to cleanse other indirect
 * blocks.
 */
static int
ffs_indirtrunc(struct inode *ip,
        ufs2_daddr_t lbn,
        ufs2_daddr_t dbn,
        ufs2_daddr_t lastbn,
        int level,
        ufs2_daddr_t *countp)
{
        struct buf *bp;
        struct fs *fs;
        struct ufsmount *ump;
        struct vnode *vp;
        caddr_t copy = NULL;
        uint64_t key;
        int i, nblocks, error = 0, allerror = 0;
        ufs2_daddr_t nb, nlbn, last;
        ufs2_daddr_t blkcount, factor, blocksreleased = 0;
        ufs1_daddr_t *bap1 = NULL;
        ufs2_daddr_t *bap2 = NULL;
#define BAP(ip, i) (I_IS_UFS1(ip) ? bap1[i] : bap2[i])

        fs = ITOFS(ip);
        ump = ITOUMP(ip);

        /*
         * Calculate index in current block of last
         * block to be kept.  -1 indicates the entire
         * block so we need not calculate the index.
         */
        factor = lbn_offset(fs, level);
        last = lastbn;
        if (lastbn > 0)
                last /= factor;
        nblocks = btodb(fs->fs_bsize);
        /*
         * Get buffer of block pointers, zero those entries corresponding
         * to blocks to be free'd, and update on disk copy first.  Since
         * double(triple) indirect before single(double) indirect, calls
         * to VOP_BMAP() on these blocks will fail.  However, we already
         * have the on-disk address, so we just pass it to bread() instead
         * of having bread() attempt to calculate it using VOP_BMAP().
         */
        vp = ITOV(ip);
        error = ffs_breadz(ump, vp, lbn, dbn, (int)fs->fs_bsize, NULL, NULL, 0,
            NOCRED, 0, NULL, &bp);
        if (error) {
                *countp = 0;
                return (error);
        }

        if (I_IS_UFS1(ip))
                bap1 = (ufs1_daddr_t *)bp->b_data;
        else
                bap2 = (ufs2_daddr_t *)bp->b_data;
        if (lastbn != -1) {
                copy = malloc(fs->fs_bsize, M_TEMP, M_WAITOK);
                bcopy((caddr_t)bp->b_data, copy, (uint64_t)fs->fs_bsize);
                for (i = last + 1; i < NINDIR(fs); i++)
                        if (I_IS_UFS1(ip))
                                bap1[i] = 0;
                        else
                                bap2[i] = 0;
                if (DOINGASYNC(vp)) {
                        bdwrite(bp);
                } else {
                        error = bwrite(bp);
                        if (error)
                                allerror = error;
                }
                if (I_IS_UFS1(ip))
                        bap1 = (ufs1_daddr_t *)copy;
                else
                        bap2 = (ufs2_daddr_t *)copy;
        }

        /*
         * Recursively free totally unused blocks.
         */
        key = ffs_blkrelease_start(ump, ITODEVVP(ip), ip->i_number);
        for (i = NINDIR(fs) - 1, nlbn = lbn + 1 - i * factor; i > last;
            i--, nlbn += factor) {
                nb = BAP(ip, i);
                if (nb == 0)
                        continue;
                if (level > SINGLE) {
                        if ((error = ffs_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
                            (ufs2_daddr_t)-1, level - 1, &blkcount)) != 0)
                                allerror = error;
                        blocksreleased += blkcount;
                }
                ffs_blkfree(ump, fs, ITODEVVP(ip), nb, fs->fs_bsize,
                    ip->i_number, vp->v_type, NULL, key);
                blocksreleased += nblocks;
        }
        ffs_blkrelease_finish(ump, key);

        /*
         * Recursively free last partial block.
         */
        if (level > SINGLE && lastbn >= 0) {
                last = lastbn % factor;
                nb = BAP(ip, i);
                if (nb != 0) {
                        error = ffs_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
                            last, level - 1, &blkcount);
                        if (error)
                                allerror = error;
                        blocksreleased += blkcount;
                }
        }
        if (copy != NULL) {
                free(copy, M_TEMP);
        } else {
                bp->b_flags |= B_INVAL | B_NOCACHE;
                brelse(bp);
        }

        *countp = blocksreleased;
        return (allerror);
}

int
ffs_rdonly(struct inode *ip)
{

        return (ITOFS(ip)->fs_ronly != 0);
}