/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989, 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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/bio.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/rwlock.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/racct.h>
#include <sys/resourcevar.h>
#include <sys/stat.h>

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

#include <ufs/ufs/extattr.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/ufs_extern.h>

static ufs_lbn_t lbn_count(struct ufsmount *, int);
static int readindir(struct vnode *, ufs_lbn_t, ufs2_daddr_t, struct buf **);

/*
 * Bmap converts the logical block number of a file to its physical block
 * number on the disk. The conversion is done by using the logical block
 * number to index into the array of block pointers described by the dinode.
 */
int
ufs_bmap(
        struct vop_bmap_args /* {
                struct vnode *a_vp;
                daddr_t a_bn;
                struct bufobj **a_bop;
                daddr_t *a_bnp;
                int *a_runp;
                int *a_runb;
        } */ *ap)
{
        ufs2_daddr_t blkno;
        int error;

        /*
         * Check for underlying vnode requests and ensure that logical
         * to physical mapping is requested.
         */
        if (ap->a_bop != NULL)
                *ap->a_bop = &VFSTOUFS(ap->a_vp->v_mount)->um_devvp->v_bufobj;
        if (ap->a_bnp == NULL)
                return (0);

        error = ufs_bmaparray(ap->a_vp, ap->a_bn, &blkno, NULL,
            ap->a_runp, ap->a_runb);
        *ap->a_bnp = blkno;
        return (error);
}

static int
readindir(struct vnode *vp,
        ufs_lbn_t lbn,
        ufs2_daddr_t daddr,
        struct buf **bpp)
{
        struct buf *bp;
        struct mount *mp;
        struct ufsmount *ump;
        int error;

        mp = vp->v_mount;
        ump = VFSTOUFS(mp);

        bp = getblk(vp, lbn, mp->mnt_stat.f_iosize, 0, 0, 0);
        if ((bp->b_flags & B_CACHE) == 0) {
                KASSERT(daddr != 0,
                    ("readindir: indirect block not in cache"));

                bp->b_blkno = blkptrtodb(ump, daddr);
                bp->b_iocmd = BIO_READ;
                bp->b_flags &= ~B_INVAL;
                bp->b_ioflags &= ~BIO_ERROR;
                vfs_busy_pages(bp, 0);
                bp->b_iooffset = dbtob(bp->b_blkno);
                bstrategy(bp);
#ifdef RACCT
                if (racct_enable) {
                        PROC_LOCK(curproc);
                        racct_add_buf(curproc, bp, 0);
                        PROC_UNLOCK(curproc);
                }
#endif
                curthread->td_ru.ru_inblock++;
                error = bufwait(bp);
                if (error != 0) {
                        brelse(bp);
                        return (error);
                }
        }
        *bpp = bp;
        return (0);
}

/*
 * Indirect blocks are now on the vnode for the file.  They are given negative
 * logical block numbers.  Indirect blocks are addressed by the negative
 * address of the first data block to which they point.  Double indirect blocks
 * are addressed by one less than the address of the first indirect block to
 * which they point.  Triple indirect blocks are addressed by one less than
 * the address of the first double indirect block to which they point.
 *
 * ufs_bmaparray does the bmap conversion, and if requested returns the
 * array of logical blocks which must be traversed to get to a block.
 * Each entry contains the offset into that block that gets you to the
 * next block and the disk address of the block (if it is assigned).
 */

int
ufs_bmaparray(struct vnode *vp,
        ufs2_daddr_t bn,
        ufs2_daddr_t *bnp,
        struct buf *nbp,
        int *runp,
        int *runb)
{
        struct inode *ip;
        struct buf *bp;
        struct ufsmount *ump;
        struct mount *mp;
        struct indir a[UFS_NIADDR+1], *ap;
        ufs2_daddr_t daddr;
        ufs_lbn_t metalbn;
        int error, num, maxrun = 0;
        int *nump;

        ap = NULL;
        ip = VTOI(vp);
        mp = vp->v_mount;
        ump = VFSTOUFS(mp);

        if (runp) {
                maxrun = mp->mnt_iosize_max / mp->mnt_stat.f_iosize - 1;
                *runp = 0;
        }

        if (runb) {
                *runb = 0;
        }

        ap = a;
        nump = &num;
        error = ufs_getlbns(vp, bn, ap, nump);
        if (error)
                return (error);

        num = *nump;
        if (num == 0) {
                if (bn >= 0 && bn < UFS_NDADDR) {
                        *bnp = blkptrtodb(ump, DIP(ip, i_db[bn]));
                } else if (bn < 0 && bn >= -UFS_NXADDR) {
                        *bnp = blkptrtodb(ump, ip->i_din2->di_extb[-1 - bn]);
                        if (*bnp == 0)
                                *bnp = -1;
                        if (nbp == NULL) {
                                /* indirect block not found */
                                return (EINVAL);
                        }
                        nbp->b_xflags |= BX_ALTDATA;
                        return (0);
                } else {
                        /* blkno out of range */
                        return (EINVAL);
                }
                /*
                 * Since this is FFS independent code, we are out of
                 * scope for the definitions of BLK_NOCOPY and
                 * BLK_SNAP, but we do know that they will fall in
                 * the range 1..um_seqinc, so we use that test and
                 * return a request for a zeroed out buffer if attempts
                 * are made to read a BLK_NOCOPY or BLK_SNAP block.
                 */
                if (IS_SNAPSHOT(ip) && DIP(ip, i_db[bn]) > 0 &&
                    DIP(ip, i_db[bn]) < ump->um_seqinc) {
                        *bnp = -1;
                } else if (*bnp == 0) {
                        *bnp = IS_SNAPSHOT(ip) ? blkptrtodb(ump,
                            bn * ump->um_seqinc) : -1;
                } else if (runp) {
                        ufs2_daddr_t bnb = bn;
                        for (++bn; bn < UFS_NDADDR && *runp < maxrun &&
                            is_sequential(ump, DIP(ip, i_db[bn - 1]),
                            DIP(ip, i_db[bn]));
                            ++bn, ++*runp);
                        bn = bnb;
                        if (runb && (bn > 0)) {
                                for (--bn; (bn >= 0) && (*runb < maxrun) &&
                                        is_sequential(ump, DIP(ip, i_db[bn]),
                                                DIP(ip, i_db[bn+1]));
                                                --bn, ++*runb);
                        }
                }
                return (0);
        }

        /* Get disk address out of indirect block array */
        daddr = DIP(ip, i_ib[ap->in_off]);

        for (bp = NULL, ++ap; --num; ++ap) {
                /*
                 * Exit the loop if there is no disk address assigned yet and
                 * the indirect block isn't in the cache, or if we were
                 * looking for an indirect block and we've found it.
                 */

                metalbn = ap->in_lbn;
                if ((daddr == 0 && !incore(&vp->v_bufobj, metalbn)) || metalbn == bn)
                        break;
                /*
                 * If we get here, we've either got the block in the cache
                 * or we have a disk address for it, go fetch it.
                 */
                if (bp)
                        bqrelse(bp);
                error = readindir(vp, metalbn, daddr, &bp);
                if (error != 0)
                        return (error);

                if (I_IS_UFS1(ip))
                        daddr = ((ufs1_daddr_t *)bp->b_data)[ap->in_off];
                else
                        daddr = ((ufs2_daddr_t *)bp->b_data)[ap->in_off];
                if ((error = UFS_CHECK_BLKNO(mp, ip->i_number, daddr,
                     mp->mnt_stat.f_iosize)) != 0) {
                        bqrelse(bp);
                        return (error);
                }
                if (I_IS_UFS1(ip)) {
                        if (num == 1 && daddr && runp) {
                                for (bn = ap->in_off + 1;
                                    bn < MNINDIR(ump) && *runp < maxrun &&
                                    is_sequential(ump,
                                    ((ufs1_daddr_t *)bp->b_data)[bn - 1],
                                    ((ufs1_daddr_t *)bp->b_data)[bn]);
                                    ++bn, ++*runp);
                                bn = ap->in_off;
                                if (runb && bn) {
                                        for (--bn; bn >= 0 && *runb < maxrun &&
                                            is_sequential(ump,
                                            ((ufs1_daddr_t *)bp->b_data)[bn],
                                            ((ufs1_daddr_t *)bp->b_data)[bn+1]);
                                            --bn, ++*runb);
                                }
                        }
                        continue;
                }
                if (num == 1 && daddr && runp) {
                        for (bn = ap->in_off + 1;
                            bn < MNINDIR(ump) && *runp < maxrun &&
                            is_sequential(ump,
                            ((ufs2_daddr_t *)bp->b_data)[bn - 1],
                            ((ufs2_daddr_t *)bp->b_data)[bn]);
                            ++bn, ++*runp);
                        bn = ap->in_off;
                        if (runb && bn) {
                                for (--bn; bn >= 0 && *runb < maxrun &&
                                    is_sequential(ump,
                                    ((ufs2_daddr_t *)bp->b_data)[bn],
                                    ((ufs2_daddr_t *)bp->b_data)[bn + 1]);
                                    --bn, ++*runb);
                        }
                }
        }
        if (bp)
                bqrelse(bp);

        /*
         * Since this is FFS independent code, we are out of scope for the
         * definitions of BLK_NOCOPY and BLK_SNAP, but we do know that they
         * will fall in the range 1..um_seqinc, so we use that test and
         * return a request for a zeroed out buffer if attempts are made
         * to read a BLK_NOCOPY or BLK_SNAP block.
         */
        if (IS_SNAPSHOT(ip) && daddr > 0 && daddr < ump->um_seqinc){
                *bnp = -1;
                return (0);
        }
        *bnp = blkptrtodb(ump, daddr);
        if (*bnp == 0) {
                if (IS_SNAPSHOT(ip))
                        *bnp = blkptrtodb(ump, bn * ump->um_seqinc);
                else
                        *bnp = -1;
        }
        return (0);
}

static ufs_lbn_t
lbn_count(struct ufsmount *ump, int level)
{
        ufs_lbn_t blockcnt;

        for (blockcnt = 1; level > 0; level--)
                blockcnt *= MNINDIR(ump);
        return (blockcnt);
}

int
ufs_bmap_seekdata(struct vnode *vp, off_t *offp)
{
        struct buf *bp;
        struct indir a[UFS_NIADDR + 1], *ap;
        struct inode *ip;
        struct mount *mp;
        struct ufsmount *ump;
        ufs2_daddr_t bn, daddr, nextbn;
        uint64_t bsize;
        off_t numblks;
        int error, num, num1, off;

        bp = NULL;
        error = 0;
        ip = VTOI(vp);
        mp = vp->v_mount;
        ump = VFSTOUFS(mp);

        if (vp->v_type != VREG || IS_SNAPSHOT(ip))
                return (EINVAL);
        if (*offp < 0 || *offp >= ip->i_size)
                return (ENXIO);

        /*
         * We could have pages on the vnode' object queue which still
         * do not have the data blocks allocated.  Convert all dirty
         * pages into buffer writes to ensure that we see all
         * allocated data.
         */
        vnode_pager_clean_sync(vp);

        bsize = mp->mnt_stat.f_iosize;
        for (bn = *offp / bsize, numblks = howmany(ip->i_size, bsize);
            bn < numblks; bn = nextbn) {
                if (bn < UFS_NDADDR) {
                        daddr = DIP(ip, i_db[bn]);
                        if (daddr != 0)
                                break;
                        nextbn = bn + 1;
                        continue;
                }

                ap = a;
                error = ufs_getlbns(vp, bn, ap, &num);
                if (error != 0)
                        break;
                MPASS(num >= 2);
                daddr = DIP(ip, i_ib[ap->in_off]);
                ap++, num--;
                for (nextbn = UFS_NDADDR, num1 = num - 1; num1 > 0; num1--)
                        nextbn += lbn_count(ump, num1);
                if (daddr == 0) {
                        nextbn += lbn_count(ump, num);
                        continue;
                }

                for (; daddr != 0 && num > 0; ap++, num--) {
                        if (bp != NULL)
                                bqrelse(bp);
                        error = readindir(vp, ap->in_lbn, daddr, &bp);
                        if (error != 0)
                                return (error);

                        /*
                         * Scan the indirect block until we find a non-zero
                         * pointer.
                         */
                        off = ap->in_off;
                        do {
                                daddr = I_IS_UFS1(ip) ?
                                    ((ufs1_daddr_t *)bp->b_data)[off] :
                                    ((ufs2_daddr_t *)bp->b_data)[off];
                        } while (daddr == 0 && ++off < MNINDIR(ump));
                        nextbn += off * lbn_count(ump, num - 1);

                        /*
                         * We need to recompute the LBNs of indirect
                         * blocks, so restart with the updated block offset.
                         */
                        if (off != ap->in_off)
                                break;
                }
                if (num == 0) {
                        /*
                         * We found a data block.
                         */
                        bn = nextbn;
                        break;
                }
        }
        if (bp != NULL)
                bqrelse(bp);
        if (bn >= numblks)
                error = ENXIO;
        if (error == 0 && *offp < bn * bsize)
                *offp = bn * bsize;
        return (error);
}

/*
 * Create an array of logical block number/offset pairs which represent the
 * path of indirect blocks required to access a data block.  The first "pair"
 * contains the logical block number of the appropriate single, double or
 * triple indirect block and the offset into the inode indirect block array.
 * Note, the logical block number of the inode single/double/triple indirect
 * block appears twice in the array, once with the offset into the i_ib and
 * once with the offset into the page itself.
 */
int
ufs_getlbns(struct vnode *vp,
        ufs2_daddr_t bn,
        struct indir *ap,
        int *nump)
{
        ufs2_daddr_t blockcnt;
        ufs_lbn_t metalbn, realbn;
        struct ufsmount *ump;
        int i, numlevels, off;

        ump = VFSTOUFS(vp->v_mount);
        if (nump)
                *nump = 0;
        numlevels = 0;
        realbn = bn;
        if (bn < 0)
                bn = -bn;

        /* The first UFS_NDADDR blocks are direct blocks. */
        if (bn < UFS_NDADDR)
                return (0);

        /*
         * Determine the number of levels of indirection.  After this loop
         * is done, blockcnt indicates the number of data blocks possible
         * at the previous level of indirection, and UFS_NIADDR - i is the
         * number of levels of indirection needed to locate the requested block.
         */
        for (blockcnt = 1, i = UFS_NIADDR, bn -= UFS_NDADDR; ;
            i--, bn -= blockcnt) {
                if (i == 0)
                        return (EFBIG);
                blockcnt *= MNINDIR(ump);
                if (bn < blockcnt)
                        break;
        }

        /* Calculate the address of the first meta-block. */
        if (realbn >= 0)
                metalbn = -(realbn - bn + UFS_NIADDR - i);
        else
                metalbn = -(-realbn - bn + UFS_NIADDR - i);

        /*
         * At each iteration, off is the offset into the bap array which is
         * an array of disk addresses at the current level of indirection.
         * The logical block number and the offset in that block are stored
         * into the argument array.
         */
        ap->in_lbn = metalbn;
        ap->in_off = off = UFS_NIADDR - i;
        ap++;
        for (++numlevels; i <= UFS_NIADDR; i++) {
                /* If searching for a meta-data block, quit when found. */
                if (metalbn == realbn)
                        break;

                blockcnt /= MNINDIR(ump);
                off = (bn / blockcnt) % MNINDIR(ump);

                ++numlevels;
                ap->in_lbn = metalbn;
                ap->in_off = off;
                ++ap;

                metalbn -= -1 + off * blockcnt;
        }
        if (nump)
                *nump = numlevels;
        return (0);
}