/*-
 *  modified for Lites 1.1
 *
 *  Aug 1995, Godmar Back (gback@cs.utah.edu)
 *  University of Utah, Department of Computer Science
 */
/*-
 * 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/param.h>
#include <sys/systm.h>
#include <sys/mount.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/endian.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/rwlock.h>
#include <sys/sdt.h>

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

#include <fs/ext2fs/fs.h>
#include <fs/ext2fs/inode.h>
#include <fs/ext2fs/ext2_mount.h>
#include <fs/ext2fs/ext2fs.h>
#include <fs/ext2fs/fs.h>
#include <fs/ext2fs/ext2_extern.h>
#include <fs/ext2fs/ext2_extattr.h>

/*
 * 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.  If we write now, then clear both IN_MODIFIED and
 * IN_LAZYMOD to reflect the presumably successful write, and if waitfor is
 * set, then wait for the write to complete.
 */
int
ext2_update(struct vnode *vp, int waitfor)
{
        struct m_ext2fs *fs;
        struct buf *bp;
        struct inode *ip;
        int error;

        ASSERT_VOP_ELOCKED(vp, "ext2_update");
        ext2_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);
        fs = ip->i_e2fs;
        if (fs->e2fs_ronly)
                return (0);
        if ((error = bread(ip->i_devvp,
            fsbtodb(fs, ino_to_fsba(fs, ip->i_number)),
            (int)fs->e2fs_bsize, NOCRED, &bp)) != 0) {
                brelse(bp);
                return (error);
        }
        error = ext2_i2ei(ip, (struct ext2fs_dinode *)((char *)bp->b_data +
            EXT2_INODE_SIZE(fs) * ino_to_fsbo(fs, ip->i_number)));
        if (error) {
                brelse(bp);
                return (error);
        }
        if (waitfor && !DOINGASYNC(vp))
                return (bwrite(bp));
        else {
                bdwrite(bp);
                return (0);
        }
}

#define SINGLE  0       /* index of single indirect block */
#define DOUBLE  1       /* index of double indirect block */
#define TRIPLE  2       /* index of triple indirect block */

/*
 * 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.
 *
 * NB: triple indirect blocks are untested.
 */
static int
ext2_indirtrunc(struct inode *ip, daddr_t lbn, daddr_t dbn,
    daddr_t lastbn, int level, e4fs_daddr_t *countp)
{
        struct buf *bp;
        struct m_ext2fs *fs = ip->i_e2fs;
        struct vnode *vp;
        e2fs_daddr_t *bap, *copy;
        int i, nblocks, error = 0, allerror = 0;
        e2fs_lbn_t nb, nlbn, last;
        e4fs_daddr_t blkcount, factor, blocksreleased = 0;

        /*
         * Calculate index in current block of last
         * block to be kept.  -1 indicates the entire
         * block so we need not calculate the index.
         */
        factor = 1;
        for (i = SINGLE; i < level; i++)
                factor *= NINDIR(fs);
        last = lastbn;
        if (lastbn > 0)
                last /= factor;
        nblocks = btodb(fs->e2fs_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 bmap on these blocks will fail.  However, we already have
         * the on disk address, so we have to set the b_blkno field
         * explicitly instead of letting bread do everything for us.
         */
        vp = ITOV(ip);
        bp = getblk(vp, lbn, (int)fs->e2fs_bsize, 0, 0, 0);
        if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0) {
                bp->b_iocmd = BIO_READ;
                if (bp->b_bcount > bp->b_bufsize)
                        panic("ext2_indirtrunc: bad buffer size");
                bp->b_blkno = dbn;
                vfs_busy_pages(bp, 0);
                bp->b_iooffset = dbtob(bp->b_blkno);
                bstrategy(bp);
                error = bufwait(bp);
        }
        if (error) {
                brelse(bp);
                *countp = 0;
                return (error);
        }
        bap = (e2fs_daddr_t *)bp->b_data;
        copy = malloc(fs->e2fs_bsize, M_TEMP, M_WAITOK);
        bcopy((caddr_t)bap, (caddr_t)copy, (u_int)fs->e2fs_bsize);
        bzero((caddr_t)&bap[last + 1],
            (NINDIR(fs) - (last + 1)) * sizeof(e2fs_daddr_t));
        if (last == -1)
                bp->b_flags |= B_INVAL;
        if (DOINGASYNC(vp)) {
                bdwrite(bp);
        } else {
                error = bwrite(bp);
                if (error)
                        allerror = error;
        }
        bap = copy;

        /*
         * Recursively free totally unused blocks.
         */
        for (i = NINDIR(fs) - 1, nlbn = lbn + 1 - i * factor; i > last;
            i--, nlbn += factor) {
                nb = le32toh(bap[i]);
                if (nb == 0)
                        continue;
                if (level > SINGLE) {
                        if ((error = ext2_indirtrunc(ip, nlbn,
                            fsbtodb(fs, nb), (int32_t)-1, level - 1, &blkcount)) != 0)
                                allerror = error;
                        blocksreleased += blkcount;
                }
                ext2_blkfree(ip, nb, fs->e2fs_bsize);
                blocksreleased += nblocks;
        }

        /*
         * Recursively free last partial block.
         */
        if (level > SINGLE && lastbn >= 0) {
                last = lastbn % factor;
                nb = le32toh(bap[i]);
                if (nb != 0) {
                        if ((error = ext2_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
                            last, level - 1, &blkcount)) != 0)
                                allerror = error;
                        blocksreleased += blkcount;
                }
        }
        free(copy, M_TEMP);
        *countp = blocksreleased;
        return (allerror);
}

/*
 * Truncate the inode oip to at most length size, freeing the
 * disk blocks.
 */
static int
ext2_ind_truncate(struct vnode *vp, off_t length, int flags, struct ucred *cred,
    struct thread *td)
{
        struct vnode *ovp = vp;
        e4fs_daddr_t lastblock;
        struct inode *oip;
        e4fs_daddr_t bn, lbn, lastiblock[EXT2_NIADDR], indir_lbn[EXT2_NIADDR];
        uint32_t oldblks[EXT2_NDADDR + EXT2_NIADDR];
#ifdef INVARIANTS
        uint32_t newblks[EXT2_NDADDR + EXT2_NIADDR];
#endif
        struct m_ext2fs *fs;
        struct buf *bp;
        int offset, size, level;
        e4fs_daddr_t count, nblocks, blocksreleased = 0;
        int error, i, allerror;
        off_t osize;
#ifdef INVARIANTS
        struct bufobj *bo;
#endif

        oip = VTOI(ovp);
#ifdef INVARIANTS
        bo = &ovp->v_bufobj;
#endif

        fs = oip->i_e2fs;
        osize = oip->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) {
                if (length > oip->i_e2fs->e2fs_maxfilesize)
                        return (EFBIG);
                vnode_pager_setsize(ovp, length);
                offset = blkoff(fs, length - 1);
                lbn = lblkno(fs, length - 1);
                flags |= BA_CLRBUF;
                error = ext2_balloc(oip, lbn, offset + 1, cred, &bp, flags);
                if (error) {
                        vnode_pager_setsize(vp, osize);
                        return (error);
                }
                oip->i_size = length;
                if (bp->b_bufsize == fs->e2fs_bsize)
                        bp->b_flags |= B_CLUSTEROK;
                if (flags & IO_SYNC)
                        bwrite(bp);
                else if (DOINGASYNC(ovp))
                        bdwrite(bp);
                else
                        bawrite(bp);
                oip->i_flag |= IN_CHANGE | IN_UPDATE;
                return (ext2_update(ovp, !DOINGASYNC(ovp)));
        }
        /*
         * Shorten the size of the file. 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 become accessible again because
         * of subsequent file growth.
         */
        /* I don't understand the comment above */
        offset = blkoff(fs, length);
        if (offset == 0) {
                oip->i_size = length;
        } else {
                lbn = lblkno(fs, length);
                flags |= BA_CLRBUF;
                error = ext2_balloc(oip, lbn, offset, cred, &bp, flags);
                if (error)
                        return (error);
                oip->i_size = length;
                size = blksize(fs, oip, lbn);
                bzero((char *)bp->b_data + offset, (u_int)(size - offset));
                allocbuf(bp, size);
                if (bp->b_bufsize == fs->e2fs_bsize)
                        bp->b_flags |= B_CLUSTEROK;
                if (flags & IO_SYNC)
                        bwrite(bp);
                else if (DOINGASYNC(ovp))
                        bdwrite(bp);
                else
                        bawrite(bp);
        }
        /*
         * 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->e2fs_bsize - 1) - 1;
        lastiblock[SINGLE] = lastblock - EXT2_NDADDR;
        lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
        lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
        nblocks = btodb(fs->e2fs_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 ext2_indirtrunc below.
         */
        for (level = TRIPLE; level >= SINGLE; level--) {
                oldblks[EXT2_NDADDR + level] = oip->i_ib[level];
                if (lastiblock[level] < 0) {
                        oip->i_ib[level] = 0;
                        lastiblock[level] = -1;
                }
        }
        for (i = 0; i < EXT2_NDADDR; i++) {
                oldblks[i] = oip->i_db[i];
                if (i > lastblock)
                        oip->i_db[i] = 0;
        }
        oip->i_flag |= IN_CHANGE | IN_UPDATE;
        allerror = ext2_update(ovp, !DOINGASYNC(ovp));

        /*
         * 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 < EXT2_NDADDR; i++) {
#ifdef INVARIANTS
                newblks[i] = oip->i_db[i];
#endif
                oip->i_db[i] = oldblks[i];
        }
        for (i = 0; i < EXT2_NIADDR; i++) {
#ifdef INVARIANTS
                newblks[EXT2_NDADDR + i] = oip->i_ib[i];
#endif
                oip->i_ib[i] = oldblks[EXT2_NDADDR + i];
        }
        oip->i_size = osize;
        error = vtruncbuf(ovp, length, (int)fs->e2fs_bsize);
        if (error && (allerror == 0))
                allerror = error;
        vnode_pager_setsize(ovp, length);

        /*
         * Indirect blocks first.
         */
        indir_lbn[SINGLE] = -EXT2_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 = oip->i_ib[level];
                if (bn != 0) {
                        error = ext2_indirtrunc(oip, indir_lbn[level],
                            fsbtodb(fs, bn), lastiblock[level], level, &count);
                        if (error)
                                allerror = error;
                        blocksreleased += count;
                        if (lastiblock[level] < 0) {
                                oip->i_ib[level] = 0;
                                ext2_blkfree(oip, bn, fs->e2fs_fsize);
                                blocksreleased += nblocks;
                        }
                }
                if (lastiblock[level] >= 0)
                        goto done;
        }

        /*
         * All whole direct blocks or frags.
         */
        for (i = EXT2_NDADDR - 1; i > lastblock; i--) {
                long bsize;

                bn = oip->i_db[i];
                if (bn == 0)
                        continue;
                oip->i_db[i] = 0;
                bsize = blksize(fs, oip, i);
                ext2_blkfree(oip, bn, bsize);
                blocksreleased += btodb(bsize);
        }
        if (lastblock < 0)
                goto done;

        /*
         * Finally, look for a change in size of the
         * last direct block; release any frags.
         */
        bn = oip->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, oip, lastblock);
                oip->i_size = length;
                newspace = blksize(fs, oip, lastblock);
                if (newspace == 0)
                        panic("ext2_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);
                        ext2_blkfree(oip, bn, oldspace - newspace);
                        blocksreleased += btodb(oldspace - newspace);
                }
        }
done:
#ifdef INVARIANTS
        for (level = SINGLE; level <= TRIPLE; level++)
                if (newblks[EXT2_NDADDR + level] != oip->i_ib[level])
                        panic("itrunc1");
        for (i = 0; i < EXT2_NDADDR; i++)
                if (newblks[i] != oip->i_db[i])
                        panic("itrunc2");
        BO_LOCK(bo);
        if (length == 0 && (bo->bo_dirty.bv_cnt != 0 ||
            bo->bo_clean.bv_cnt != 0))
                panic("itrunc3");
        BO_UNLOCK(bo);
#endif  /* INVARIANTS */
        /*
         * Put back the real size.
         */
        oip->i_size = length;
        if (oip->i_blocks >= blocksreleased)
                oip->i_blocks -= blocksreleased;
        else                            /* sanity */
                oip->i_blocks = 0;
        oip->i_flag |= IN_CHANGE;
        vnode_pager_setsize(ovp, length);
        return (allerror);
}

static int
ext2_ext_truncate(struct vnode *vp, off_t length, int flags,
    struct ucred *cred, struct thread *td)
{
        struct vnode *ovp = vp;
        int32_t lastblock;
        struct m_ext2fs *fs;
        struct inode *oip;
        struct buf *bp;
        uint32_t lbn, offset;
        int error, size;
        off_t osize;

        oip = VTOI(ovp);
        fs = oip->i_e2fs;
        osize = oip->i_size;

        if (osize < length) {
                if (length > oip->i_e2fs->e2fs_maxfilesize) {
                        return (EFBIG);
                }
                vnode_pager_setsize(ovp, length);
                offset = blkoff(fs, length - 1);
                lbn = lblkno(fs, length - 1);
                flags |= BA_CLRBUF;
                error = ext2_balloc(oip, lbn, offset + 1, cred, &bp, flags);
                if (error) {
                        vnode_pager_setsize(vp, osize);
                        return (error);
                }
                oip->i_size = length;
                if (bp->b_bufsize == fs->e2fs_bsize)
                        bp->b_flags |= B_CLUSTEROK;
                if (flags & IO_SYNC)
                        bwrite(bp);
                else if (DOINGASYNC(ovp))
                        bdwrite(bp);
                else
                        bawrite(bp);
                oip->i_flag |= IN_CHANGE | IN_UPDATE;
                return (ext2_update(ovp, !DOINGASYNC(ovp)));
        }

        lastblock = (length + fs->e2fs_bsize - 1) / fs->e2fs_bsize;
        error = ext4_ext_remove_space(oip, lastblock, flags, cred, td);
        if (error)
                return (error);

        offset = blkoff(fs, length);
        if (offset == 0) {
                oip->i_size = length;
        } else {
                lbn = lblkno(fs, length);
                flags |= BA_CLRBUF;
                error = ext2_balloc(oip, lbn, offset, cred, &bp, flags);
                if (error) {
                        return (error);
                }
                oip->i_size = length;
                size = blksize(fs, oip, lbn);
                bzero((char *)bp->b_data + offset, (u_int)(size - offset));
                allocbuf(bp, size);
                if (bp->b_bufsize == fs->e2fs_bsize)
                        bp->b_flags |= B_CLUSTEROK;
                if (flags & IO_SYNC)
                        bwrite(bp);
                else if (DOINGASYNC(ovp))
                        bdwrite(bp);
                else
                        bawrite(bp);
        }

        oip->i_size = osize;
        error = vtruncbuf(ovp, length, (int)fs->e2fs_bsize);
        if (error)
                return (error);

        vnode_pager_setsize(ovp, length);

        oip->i_size = length;
        oip->i_flag |= IN_CHANGE | IN_UPDATE;
        error = ext2_update(ovp, !DOINGASYNC(ovp));

        return (error);
}

/*
 * Truncate the inode ip to at most length size, freeing the
 * disk blocks.
 */
int
ext2_truncate(struct vnode *vp, off_t length, int flags, struct ucred *cred,
    struct thread *td)
{
        struct inode *ip;
        int error;

        ASSERT_VOP_LOCKED(vp, "ext2_truncate");

        if (length < 0)
                return (EINVAL);

        ip = VTOI(vp);
        if (vp->v_type == VLNK &&
            ip->i_size < VFSTOEXT2(vp->v_mount)->um_e2fs->e2fs_maxsymlinklen) {
#ifdef INVARIANTS
                if (length != 0)
                        panic("ext2_truncate: partial truncate of symlink");
#endif
                bzero((char *)&ip->i_shortlink, (u_int)ip->i_size);
                ip->i_size = 0;
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                return (ext2_update(vp, 1));
        }
        if (ip->i_size == length) {
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                return (ext2_update(vp, 0));
        }

        if (ip->i_flag & IN_E4EXTENTS)
                error = ext2_ext_truncate(vp, length, flags, cred, td);
        else
                error = ext2_ind_truncate(vp, length, flags, cred, td);
        cluster_init_vn(&ip->i_clusterw);

        return (error);
}

/*
 *      discard preallocated blocks
 */
int
ext2_inactive(struct vop_inactive_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct inode *ip = VTOI(vp);
        struct thread *td = curthread;
        int mode, error = 0;

        /*
         * Ignore inodes related to stale file handles.
         */
        if (ip->i_mode == 0)
                goto out;
        if (ip->i_nlink <= 0) {
                ext2_extattr_free(ip);
                error = ext2_truncate(vp, (off_t)0, 0, NOCRED, td);
                ip->i_rdev = 0;
                mode = ip->i_mode;
                ip->i_mode = 0;
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                ext2_vfree(vp, ip->i_number, mode);
        }
        if (ip->i_flag & (IN_ACCESS | IN_CHANGE | IN_MODIFIED | IN_UPDATE))
                ext2_update(vp, 0);
out:
        /*
         * If we are done with the inode, reclaim it
         * so that it can be reused immediately.
         */
        if (ip->i_mode == 0)
                vrecycle(vp);
        return (error);
}

/*
 * Reclaim an inode so that it can be used for other purposes.
 */
int
ext2_reclaim(struct vop_reclaim_args *ap)
{
        struct inode *ip;
        struct vnode *vp = ap->a_vp;

        ip = VTOI(vp);
        if (ip->i_flag & IN_LAZYMOD) {
                ip->i_flag |= IN_MODIFIED;
                ext2_update(vp, 0);
        }
        vfs_hash_remove(vp);
        free(vp->v_data, M_EXT2NODE);
        vp->v_data = 0;
        return (0);
}