/*      $OpenBSD: ext2fs_balloc.c,v 1.27 2019/07/19 00:24:31 cheloha Exp $      */
/*      $NetBSD: ext2fs_balloc.c,v 1.10 2001/07/04 21:16:01 chs Exp $   */

/*
 * Copyright (c) 1997 Manuel Bouyer.
 * 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.
 *
 *      @(#)ffs_balloc.c        8.4 (Berkeley) 9/23/93
 * Modified for ext2fs by Manuel Bouyer.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/vnode.h>

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

#include <ufs/ext2fs/ext2fs.h>
#include <ufs/ext2fs/ext2fs_extern.h>

/*
 * Balloc defines the structure of file system storage
 * by allocating the physical blocks on a device given
 * the inode and the logical block number in a file.
 */
int
ext2fs_buf_alloc(struct inode *ip, u_int32_t bn, int size, struct ucred *cred,
    struct buf **bpp, int flags)
{
        struct m_ext2fs *fs;
        struct buf *bp, *nbp;
        struct vnode *vp = ITOV(ip);
        struct indir indirs[NIADDR + 2];
        u_int32_t nb, newb, *bap;
        int num, i, error;
        u_int deallocated;
        u_int32_t *allocib, *blkp, *allocblk, allociblk[NIADDR + 1];
        int unwindidx = -1;
        daddr_t lbn, pref;

        *bpp = NULL;
        fs = ip->i_e2fs;
        lbn = bn;

        /*
         * The first NDADDR blocks are direct blocks
         */
        if (bn < NDADDR) {
                nb = letoh32(ip->i_e2fs_blocks[bn]);
                if (nb != 0) {
                        error = bread(vp, bn, fs->e2fs_bsize, &bp);
                        if (error) {
                                brelse(bp);
                                return (error);
                        }
                        *bpp = bp;
                        return (0);
                }

                /*
                 * allocate a new direct block.
                 */
                error = ext2fs_alloc(ip, bn,
                    ext2fs_blkpref(ip, bn, (int)bn, &ip->i_e2fs_blocks[0]),
                    cred, &newb);
                if (error)
                        return (error);
                ip->i_e2fs_last_lblk = lbn;
                ip->i_e2fs_last_blk = newb;
                ip->i_e2fs_blocks[bn] = htole32(newb);
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                bp = getblk(vp, bn, fs->e2fs_bsize, 0, INFSLP);
                bp->b_blkno = fsbtodb(fs, newb);
                if (flags & B_CLRBUF)
                        clrbuf(bp);
                *bpp = bp;
                return (0);
        }
        /*
         * Determine the number of levels of indirection.
         */
        pref = 0;
        if ((error = ufs_getlbns(vp, bn, indirs, &num)) != 0)
                return(error);
#ifdef DIAGNOSTIC
        if (num < 1)
                panic ("ext2fs_balloc: ufs_getlbns returned indirect block");
#endif
        /*
         * Fetch the first indirect block allocating if necessary.
         */
        --num;
        nb = letoh32(ip->i_e2fs_blocks[NDADDR + indirs[0].in_off]);
        allocib = NULL;
        allocblk = allociblk;
        if (nb == 0) {
                pref = ext2fs_blkpref(ip, lbn, 0, NULL);
                error = ext2fs_alloc(ip, lbn, pref, cred, &newb);
                if (error)
                        return (error);
                nb = newb;
                *allocblk++ = nb;
                ip->i_e2fs_last_blk = newb;
                bp = getblk(vp, indirs[1].in_lbn, fs->e2fs_bsize, 0, INFSLP);
                bp->b_blkno = fsbtodb(fs, newb);
                clrbuf(bp);
                /*
                 * Write synchronously so that indirect blocks
                 * never point at garbage.
                 */
                if ((error = bwrite(bp)) != 0)
                        goto fail;
                unwindidx = 0;
                allocib = &ip->i_e2fs_blocks[NDADDR + indirs[0].in_off];
                *allocib = htole32(newb);
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
        }
        /*
         * Fetch through the indirect blocks, allocating as necessary.
         */
        for (i = 1;;) {
                error = bread(vp, indirs[i].in_lbn, (int)fs->e2fs_bsize, &bp);
                if (error) {
                        brelse(bp);
                        goto fail;
                }
                bap = (u_int32_t *)bp->b_data;
                nb = letoh32(bap[indirs[i].in_off]);
                if (i == num)
                        break;
                i++;
                if (nb != 0) {
                        brelse(bp);
                        continue;
                }
                pref = ext2fs_blkpref(ip, lbn, 0, NULL);
                error = ext2fs_alloc(ip, lbn, pref, cred, &newb);
                if (error) {
                        brelse(bp);
                        goto fail;
                }
                nb = newb;
                *allocblk++ = nb;
                ip->i_e2fs_last_blk = newb;
                nbp = getblk(vp, indirs[i].in_lbn, fs->e2fs_bsize, 0, INFSLP);
                nbp->b_blkno = fsbtodb(fs, nb);
                clrbuf(nbp);
                /*
                 * Write synchronously so that indirect blocks
                 * never point at garbage.
                 */
                if ((error = bwrite(nbp)) != 0) {
                        brelse(bp);
                        goto fail;
                }
                if (unwindidx < 0)
                        unwindidx = i - 1;
                bap[indirs[i - 1].in_off] = htole32(nb);
                /*
                 * If required, write synchronously, otherwise use
                 * delayed write.
                 */
                if (flags & B_SYNC) {
                        bwrite(bp);
                } else {
                        bdwrite(bp);
                }
        }
        /*
         * Get the data block, allocating if necessary.
         */
        if (nb == 0) {
                pref = ext2fs_blkpref(ip, lbn, indirs[num].in_off, bap);
                error = ext2fs_alloc(ip, lbn, pref, cred, &newb);
                if (error) {
                        brelse(bp);
                        goto fail;
                }
                nb = newb;
                *allocblk++ = nb;
                ip->i_e2fs_last_lblk = lbn;
                ip->i_e2fs_last_blk = newb;
                bap[indirs[num].in_off] = htole32(nb);
                /*
                 * If required, write synchronously, otherwise use
                 * delayed write.
                 */
                if (flags & B_SYNC) {
                        bwrite(bp);
                } else {
                        bdwrite(bp);
                }
                nbp = getblk(vp, lbn, fs->e2fs_bsize, 0, INFSLP);
                nbp->b_blkno = fsbtodb(fs, nb);
                if (flags & B_CLRBUF)
                        clrbuf(nbp);
                *bpp = nbp;
                return (0);
        }
        brelse(bp);
        if (flags & B_CLRBUF) {
                error = bread(vp, lbn, (int)fs->e2fs_bsize, &nbp);
                if (error) {
                        brelse(nbp);
                        goto fail;
                }
        } else {
                nbp = getblk(vp, lbn, fs->e2fs_bsize, 0, INFSLP);
                nbp->b_blkno = fsbtodb(fs, nb);
        }

        *bpp = nbp;
        return (0);
fail:
        /*
         * If we have failed part way through block allocation, we
         * have to deallocate any indirect blocks that we have allocated.
         */
        for (deallocated = 0, blkp = allociblk; blkp < allocblk; blkp++) {
                ext2fs_blkfree(ip, *blkp);
                deallocated += fs->e2fs_bsize;
        }
        if (unwindidx >= 0) {
                if (unwindidx == 0) {
                        *allocib = 0;
                } else {
                        int r;

                        r = bread(vp, indirs[unwindidx].in_lbn,
                            (int)fs->e2fs_bsize, &bp);
                        if (r) {
                                panic("Could not unwind indirect block, error %d", r);
                        } else {
                                bap = (u_int32_t *)bp->b_data;
                                bap[indirs[unwindidx].in_off] = 0;
                                if (flags & B_SYNC)
                                        bwrite(bp);
                                else
                                        bdwrite(bp);
                        }
                }
                for (i = unwindidx + 1; i <= num; i++) {
                        bp = getblk(vp, indirs[i].in_lbn, (int)fs->e2fs_bsize,
                            0, INFSLP);
                        bp->b_flags |= B_INVAL;
                        brelse(bp);
                }
        }
        if (deallocated) {
                ip->i_e2fs_nblock -= btodb(deallocated);
                ip->i_e2fs_flags |= IN_CHANGE | IN_UPDATE;
        }
        return error;
}