/*      $NetBSD: ulfs_bmap.c,v 1.9 2017/03/30 09:10:08 hannken Exp $    */
/*  from NetBSD: ufs_bmap.c,v 1.50 2013/01/22 09:39:18 dholland Exp  */

/*
 * 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.
 *
 *      @(#)ufs_bmap.c  8.8 (Berkeley) 8/11/95
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ulfs_bmap.c,v 1.9 2017/03/30 09:10:08 hannken Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/stat.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/resourcevar.h>
#include <sys/trace.h>

#include <miscfs/specfs/specdev.h>

#include <ufs/lfs/ulfs_inode.h>
#include <ufs/lfs/ulfsmount.h>
#include <ufs/lfs/ulfs_extern.h>
#include <ufs/lfs/ulfs_bswap.h>

static bool
ulfs_issequential(const struct lfs *fs, daddr_t daddr0, daddr_t daddr1)
{

        /* for ulfs, blocks in a hole is not 'contiguous'. */
        if (daddr0 == 0)
                return false;

        return (daddr0 + fs->um_seqinc == daddr1);
}

/*
 * This is used for block pointers in inodes and elsewhere, which can
 * contain the magic value UNWRITTEN, which is -2. This is mishandled
 * by u32 -> u64 promotion unless special-cased.
 *
 * XXX this should be rolled into better inode accessors and go away.
 */
static inline uint64_t
ulfs_fix_unwritten(uint32_t val)
{
        if (val == (uint32_t)UNWRITTEN) {
                return (uint64_t)(int64_t)UNWRITTEN;
        } else {
                return val;
        }
}


/*
 * 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
ulfs_bmap(void *v)
{
        struct vop_bmap_args /* {
                struct vnode *a_vp;
                daddr_t  a_bn;
                struct vnode **a_vpp;
                daddr_t *a_bnp;
                int *a_runp;
        } */ *ap = v;
        int error;

        /*
         * Check for underlying vnode requests and ensure that logical
         * to physical mapping is requested.
         */
        if (ap->a_vpp != NULL)
                *ap->a_vpp = VTOI(ap->a_vp)->i_devvp;
        if (ap->a_bnp == NULL)
                return (0);

        error = ulfs_bmaparray(ap->a_vp, ap->a_bn, ap->a_bnp, NULL, NULL,
            ap->a_runp, ulfs_issequential);
        return error;
}

/*
 * 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.
 *
 * ulfs_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
ulfs_bmaparray(struct vnode *vp, daddr_t bn, daddr_t *bnp, struct indir *ap,
    int *nump, int *runp, ulfs_issequential_callback_t is_sequential)
{
        struct inode *ip;
        struct buf *bp, *cbp;
        struct ulfsmount *ump;
        struct lfs *fs;
        struct mount *mp;
        struct indir a[ULFS_NIADDR + 1], *xap;
        daddr_t daddr;
        daddr_t metalbn;
        int error, maxrun = 0, num;

        ip = VTOI(vp);
        mp = vp->v_mount;
        ump = ip->i_ump;
        fs = ip->i_lfs;
        KASSERTMSG(((ap == NULL) == (nump == NULL)),
            "ulfs_bmaparray: invalid arguments: ap=%p, nump=%p", ap, nump);

        if (runp) {
                /*
                 * XXX
                 * If MAXBSIZE is the largest transfer the disks can handle,
                 * we probably want maxrun to be 1 block less so that we
                 * don't create a block larger than the device can handle.
                 */
                *runp = 0;
                maxrun = MAXPHYS / mp->mnt_stat.f_iosize - 1;
        }

        if (bn >= 0 && bn < ULFS_NDADDR) {
                if (nump != NULL)
                        *nump = 0;
                if (ump->um_fstype == ULFS1)
                        daddr = ulfs_fix_unwritten(ulfs_rw32(ip->i_din->u_32.di_db[bn],
                            ULFS_MPNEEDSWAP(fs)));
                else
                        daddr = ulfs_rw64(ip->i_din->u_64.di_db[bn],
                            ULFS_MPNEEDSWAP(fs));
                *bnp = blkptrtodb(fs, daddr);
                /*
                 * 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 ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL)) == SF_SNAPSHOT
                    && daddr > 0 &&
                    daddr < fs->um_seqinc) {
                        *bnp = -1;
                } else if (*bnp == 0) {
                        if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL))
                            == SF_SNAPSHOT) {
                                *bnp = blkptrtodb(fs, bn * fs->um_seqinc);
                        } else {
                                *bnp = -1;
                        }
                } else if (runp) {
                        if (ump->um_fstype == ULFS1) {
                                for (++bn; bn < ULFS_NDADDR && *runp < maxrun &&
                                    is_sequential(fs,
                                        ulfs_fix_unwritten(ulfs_rw32(ip->i_din->u_32.di_db[bn - 1],
                                            ULFS_MPNEEDSWAP(fs))),
                                        ulfs_fix_unwritten(ulfs_rw32(ip->i_din->u_32.di_db[bn],
                                            ULFS_MPNEEDSWAP(fs))));
                                    ++bn, ++*runp);
                        } else {
                                for (++bn; bn < ULFS_NDADDR && *runp < maxrun &&
                                    is_sequential(fs,
                                        ulfs_rw64(ip->i_din->u_64.di_db[bn - 1],
                                            ULFS_MPNEEDSWAP(fs)),
                                        ulfs_rw64(ip->i_din->u_64.di_db[bn],
                                            ULFS_MPNEEDSWAP(fs)));
                                    ++bn, ++*runp);
                        }
                }
                return (0);
        }

        xap = ap == NULL ? a : ap;
        if (!nump)
                nump = &num;
        if ((error = ulfs_getlbns(vp, bn, xap, nump)) != 0)
                return (error);

        num = *nump;

        /* Get disk address out of indirect block array */
        // XXX clean this up
        if (ump->um_fstype == ULFS1)
                daddr = ulfs_fix_unwritten(ulfs_rw32(ip->i_din->u_32.di_ib[xap->in_off],
                    ULFS_MPNEEDSWAP(fs)));
        else
                daddr = ulfs_rw64(ip->i_din->u_64.di_ib[xap->in_off],
                    ULFS_MPNEEDSWAP(fs));

        for (bp = NULL, ++xap; --num; ++xap) {
                /*
                 * 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 = xap->in_lbn;
                if (metalbn == bn)
                        break;
                if (daddr == 0) {
                        mutex_enter(&bufcache_lock);
                        cbp = incore(vp, metalbn);
                        mutex_exit(&bufcache_lock);
                        if (cbp == NULL)
                                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)
                        brelse(bp, 0);

                xap->in_exists = 1;
                bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0);
                if (bp == NULL) {

                        /*
                         * getblk() above returns NULL only iff we are
                         * pagedaemon.  See the implementation of getblk
                         * for detail.
                         */

                        return (ENOMEM);
                }
                if (bp->b_oflags & (BO_DONE | BO_DELWRI)) {
                        trace(TR_BREADHIT, pack(vp, size), metalbn);
                } else {
                        KASSERTMSG(daddr,
                            "ulfs_bmaparray: indirect block not in cache");
                        trace(TR_BREADMISS, pack(vp, size), metalbn);
                        bp->b_blkno = blkptrtodb(fs, daddr);
                        bp->b_flags |= B_READ;
                        BIO_SETPRIO(bp, BPRIO_TIMECRITICAL);
                        VOP_STRATEGY(vp, bp);
                        curlwp->l_ru.ru_inblock++;      /* XXX */
                        if ((error = biowait(bp)) != 0) {
                                brelse(bp, 0);
                                return (error);
                        }
                }
                if (ump->um_fstype == ULFS1) {
                        daddr = ulfs_fix_unwritten(ulfs_rw32(((u_int32_t *)bp->b_data)[xap->in_off],
                            ULFS_MPNEEDSWAP(fs)));
                        if (num == 1 && daddr && runp) {
                                for (bn = xap->in_off + 1;
                                    bn < MNINDIR(fs) && *runp < maxrun &&
                                    is_sequential(fs,
                                        ulfs_fix_unwritten(ulfs_rw32(((int32_t *)bp->b_data)[bn-1],
                                            ULFS_MPNEEDSWAP(fs))),
                                        ulfs_fix_unwritten(ulfs_rw32(((int32_t *)bp->b_data)[bn],
                                            ULFS_MPNEEDSWAP(fs))));
                                    ++bn, ++*runp);
                        }
                } else {
                        daddr = ulfs_rw64(((u_int64_t *)bp->b_data)[xap->in_off],
                            ULFS_MPNEEDSWAP(fs));
                        if (num == 1 && daddr && runp) {
                                for (bn = xap->in_off + 1;
                                    bn < MNINDIR(fs) && *runp < maxrun &&
                                    is_sequential(fs,
                                        ulfs_rw64(((int64_t *)bp->b_data)[bn-1],
                                            ULFS_MPNEEDSWAP(fs)),
                                        ulfs_rw64(((int64_t *)bp->b_data)[bn],
                                            ULFS_MPNEEDSWAP(fs)));
                                    ++bn, ++*runp);
                        }
                }
        }
        if (bp)
                brelse(bp, 0);

        /*
         * 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 ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL)) == SF_SNAPSHOT
            && daddr > 0 && daddr < fs->um_seqinc) {
                *bnp = -1;
                return (0);
        }
        *bnp = blkptrtodb(fs, daddr);
        if (*bnp == 0) {
                if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL))
                    == SF_SNAPSHOT) {
                        *bnp = blkptrtodb(fs, bn * fs->um_seqinc);
                } else {
                        *bnp = -1;
                }
        }
        return (0);
}

/*
 * 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_ffs1_ib and
 * once with the offset into the page itself.
 */
int
ulfs_getlbns(struct vnode *vp, daddr_t bn, struct indir *ap, int *nump)
{
        daddr_t metalbn, realbn;
        struct ulfsmount *ump;
        struct lfs *fs;
        int64_t blockcnt;
        int lbc;
        int i, numlevels, off;

        ump = VFSTOULFS(vp->v_mount);
        fs = ump->um_lfs;
        if (nump)
                *nump = 0;
        numlevels = 0;
        realbn = bn;
        if (bn < 0)
                bn = -bn;
        KASSERT(bn >= ULFS_NDADDR);

        /*
         * Determine the number of levels of indirection.  After this loop
         * is done, blockcnt indicates the number of data blocks possible
         * at the given level of indirection, and ULFS_NIADDR - i is the number
         * of levels of indirection needed to locate the requested block.
         */

        bn -= ULFS_NDADDR;
        for (lbc = 0, i = ULFS_NIADDR;; i--, bn -= blockcnt) {
                if (i == 0)
                        return (EFBIG);

                lbc += fs->um_lognindir;
                blockcnt = (int64_t)1 << lbc;

                if (bn < blockcnt)
                        break;
        }

        /* Calculate the address of the first meta-block. */
        metalbn = -((realbn >= 0 ? realbn : -realbn) - bn + ULFS_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 = ULFS_NIADDR - i;
        ap->in_exists = 0;
        ap++;
        for (++numlevels; i <= ULFS_NIADDR; i++) {
                /* If searching for a meta-data block, quit when found. */
                if (metalbn == realbn)
                        break;

                lbc -= fs->um_lognindir;
                off = (bn >> lbc) & (MNINDIR(fs) - 1);

                ++numlevels;
                ap->in_lbn = metalbn;
                ap->in_off = off;
                ap->in_exists = 0;
                ++ap;

                metalbn -= -1 + ((int64_t)off << lbc);
        }
        if (nump)
                *nump = numlevels;
        return (0);
}