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/*

 *  linux/fs/minix/bitmap.c

 *

 *  Copyright (C) 1991, 1992  Linus Torvalds

 */

/*

 * Modified for 680x0 by Hamish Macdonald

 * Fixed for 680x0 by Andreas Schwab

 */

/* bitmap.c contains the code that handles the inode and block bitmaps */

#include "minix.h"

#include <linux/smp_lock.h>

#include <linux/buffer_head.h>

#include <linux/bitops.h>

#include <linux/sched.h>

static const int nibblemap[] = { 4,3,3,2,3,2,2,1,3,2,2,1,2,1,1,0 };

static unsigned long count_free(struct buffer_head *map[], unsigned numblocks, __u32 numbits)

{

        unsigned i, j, sum = 0;

        struct buffer_head *bh;

        for (i=0; i<numblocks-1; i++) {

                if (!(bh=map[i]))

                        return(0);

                for (j=0; j<bh->b_size; j++)

                        sum += nibblemap[bh->b_data[j] & 0xf]

                                + nibblemap[(bh->b_data[j]>>4) & 0xf];

        }

        if (numblocks==0 || !(bh=map[numblocks-1]))

                return(0);

        i = ((numbits - (numblocks-1) * bh->b_size * 8) / 16) * 2;

        for (j=0; j<i; j++) {

                sum += nibblemap[bh->b_data[j] & 0xf]

                        + nibblemap[(bh->b_data[j]>>4) & 0xf];

        }

        i = numbits%16;

        if (i!=0) {

                i = *(__u16 *)(&bh->b_data[j]) | ~((1<<i) - 1);

                sum += nibblemap[i & 0xf] + nibblemap[(i>>4) & 0xf];

                sum += nibblemap[(i>>8) & 0xf] + nibblemap[(i>>12) & 0xf];

        }

        return(sum);

}

void minix_free_block(struct inode *inode, unsigned long block)

{

        struct super_block *sb = inode->i_sb;

        struct minix_sb_info *sbi = minix_sb(sb);

        struct buffer_head *bh;

        int k = sb->s_blocksize_bits + 3;

        unsigned long bit, zone;

        if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) {

                printk("Trying to free block not in datazone\n");

                return;

        }

        zone = block - sbi->s_firstdatazone + 1;

        bit = zone & ((1<<k) - 1);

        zone >>= k;

        if (zone >= sbi->s_zmap_blocks) {

                printk("minix_free_block: nonexistent bitmap buffer\n");

                return;

        }

        bh = sbi->s_zmap[zone];

        lock_kernel();

        if (!minix_test_and_clear_bit(bit, bh->b_data))

                printk("minix_free_block (%s:%lu): bit already cleared\n",

                       sb->s_id, block);

        unlock_kernel();

        mark_buffer_dirty(bh);

        return;

}

int minix_new_block(struct inode * inode)

{

        struct minix_sb_info *sbi = minix_sb(inode->i_sb);

        int bits_per_zone = 8 * inode->i_sb->s_blocksize;

        int i;

        for (i = 0; i < sbi->s_zmap_blocks; i++) {

                struct buffer_head *bh = sbi->s_zmap[i];

                int j;

                lock_kernel();

                j = minix_find_first_zero_bit(bh->b_data, bits_per_zone);

                if (j < bits_per_zone) {

                        minix_set_bit(j, bh->b_data);

                        unlock_kernel();

                        mark_buffer_dirty(bh);

                        j += i * bits_per_zone + sbi->s_firstdatazone-1;

                        if (j < sbi->s_firstdatazone || j >= sbi->s_nzones)

                                break;

                        return j;

                }

                unlock_kernel();

        }

        return 0;

}

unsigned long minix_count_free_blocks(struct minix_sb_info *sbi)

{

        return (count_free(sbi->s_zmap, sbi->s_zmap_blocks,

                sbi->s_nzones - sbi->s_firstdatazone + 1)

                << sbi->s_log_zone_size);

}

struct minix_inode *

minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)

{

        int block;

        struct minix_sb_info *sbi = minix_sb(sb);

        struct minix_inode *p;

        if (!ino || ino > sbi->s_ninodes) {

                printk("Bad inode number on dev %s: %ld is out of range\n",

                       sb->s_id, (long)ino);

                return NULL;

        }

        ino--;

        block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +

                 ino / MINIX_INODES_PER_BLOCK;

        *bh = sb_bread(sb, block);

        if (!*bh) {

                printk("Unable to read inode block\n");

                return NULL;

        }

        p = (void *)(*bh)->b_data;

        return p + ino % MINIX_INODES_PER_BLOCK;

}

struct minix2_inode *

minix_V2_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)

{

        int block;

        struct minix_sb_info *sbi = minix_sb(sb);

        struct minix2_inode *p;

        int minix2_inodes_per_block = sb->s_blocksize / sizeof(struct minix2_inode);

        *bh = NULL;

        if (!ino || ino > sbi->s_ninodes) {

                printk("Bad inode number on dev %s: %ld is out of range\n",

                       sb->s_id, (long)ino);

                return NULL;

        }

        ino--;

        block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +

                 ino / minix2_inodes_per_block;

        *bh = sb_bread(sb, block);

        if (!*bh) {

                printk("Unable to read inode block\n");

                return NULL;

        }

        p = (void *)(*bh)->b_data;

        return p + ino % minix2_inodes_per_block;

}

/* Clear the link count and mode of a deleted inode on disk. */

static void minix_clear_inode(struct inode *inode)

{

        struct buffer_head *bh = NULL;

        if (INODE_VERSION(inode) == MINIX_V1) {

                struct minix_inode *raw_inode;

                raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);

                if (raw_inode) {

                        raw_inode->i_nlinks = 0;

                        raw_inode->i_mode = 0;

                }

        } else {

                struct minix2_inode *raw_inode;

                raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);

                if (raw_inode) {

                        raw_inode->i_nlinks = 0;

                        raw_inode->i_mode = 0;

                }

        }

        if (bh) {

                mark_buffer_dirty(bh);

                brelse (bh);

        }

}

void minix_free_inode(struct inode * inode)

{

        struct super_block *sb = inode->i_sb;

        struct minix_sb_info *sbi = minix_sb(inode->i_sb);

        struct buffer_head *bh;

        int k = sb->s_blocksize_bits + 3;

        unsigned long ino, bit;

        ino = inode->i_ino;

        if (ino < 1 || ino > sbi->s_ninodes) {

                printk("minix_free_inode: inode 0 or nonexistent inode\n");

                goto out;

        }

        bit = ino & ((1<<k) - 1);

        ino >>= k;

        if (ino >= sbi->s_imap_blocks) {

                printk("minix_free_inode: nonexistent imap in superblock\n");

                goto out;

        }

        minix_clear_inode(inode);       /* clear on-disk copy */

        bh = sbi->s_imap[ino];

        lock_kernel();

        if (!minix_test_and_clear_bit(bit, bh->b_data))

                printk("minix_free_inode: bit %lu already cleared\n", bit);

        unlock_kernel();

        mark_buffer_dirty(bh);

 out:

        clear_inode(inode);             /* clear in-memory copy */

}

struct inode * minix_new_inode(const struct inode * dir, int * error)

{

        struct super_block *sb = dir->i_sb;

        struct minix_sb_info *sbi = minix_sb(sb);

        struct inode *inode = new_inode(sb);

        struct buffer_head * bh;

        int bits_per_zone = 8 * sb->s_blocksize;

        unsigned long j;

        int i;

        if (!inode) {

                *error = -ENOMEM;

                return NULL;

        }

        j = bits_per_zone;

        bh = NULL;

        *error = -ENOSPC;

        lock_kernel();

        for (i = 0; i < sbi->s_imap_blocks; i++) {

                bh = sbi->s_imap[i];

                j = minix_find_first_zero_bit(bh->b_data, bits_per_zone);

                if (j < bits_per_zone)

                        break;

        }

        if (!bh || j >= bits_per_zone) {

                unlock_kernel();

                iput(inode);

                return NULL;

        }

        if (minix_test_and_set_bit(j, bh->b_data)) {    /* shouldn't happen */

                unlock_kernel();

                printk("minix_new_inode: bit already set\n");

                iput(inode);

                return NULL;

        }

        unlock_kernel();

        mark_buffer_dirty(bh);

        j += i * bits_per_zone;

        if (!j || j > sbi->s_ninodes) {

                iput(inode);

                return NULL;

        }

        inode->i_uid = current->fsuid;

        inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;

        inode->i_ino = j;

        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;

        inode->i_blocks = 0;

        memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u));

        insert_inode_hash(inode);

        mark_inode_dirty(inode);

        *error = 0;

        return inode;

}

unsigned long minix_count_free_inodes(struct minix_sb_info *sbi)

{

        return count_free(sbi->s_imap, sbi->s_imap_blocks, sbi->s_ninodes + 1);

}