linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 *  linux/fs/affs/bitmap.c

 *

 *  (c) 1996 Hans-Joachim Widmaier

 *

 *  bitmap.c contains the code that handles all bitmap related stuff -

 *  block allocation, deallocation, calculation of free space.

 */

​

#include <linux/slab.h>

#include "affs.h"

​

u32

affs_count_free_blocks(struct super_block *sb)

{

    struct affs_bm_info *bm;

    u32 free;

    int i;

​

    pr_debug("%s()\n", __func__);

​

    if (sb_rdonly(sb))

        return 0;

​

    mutex_lock(&AFFS_SB(sb)->s_bmlock);

​

    bm = AFFS_SB(sb)->s_bitmap;

    free = 0;

    for (i = AFFS_SB(sb)->s_bmap_count; i > 0; bm++, i--)

        free += bm->bm_free;

​

    mutex_unlock(&AFFS_SB(sb)->s_bmlock);

​

    return free;

}

​

void

affs_free_block(struct super_block *sb, u32 block)

{

    struct affs_sb_info *sbi = AFFS_SB(sb);

    struct affs_bm_info *bm;

    struct buffer_head *bh;

    u32 blk, bmap, bit, mask, tmp;

    __be32 *data;

​

    pr_debug("%s(%u)\n", __func__, block);

​

    if (block > sbi->s_partition_size)

        goto err_range;

​

    blk     = block - sbi->s_reserved;

    bmap    = blk / sbi->s_bmap_bits;

    bit     = blk % sbi->s_bmap_bits;

    bm      = &sbi->s_bitmap[bmap];

​

    mutex_lock(&sbi->s_bmlock);

​

    bh = sbi->s_bmap_bh;

    if (sbi->s_last_bmap != bmap) {

        affs_brelse(bh);

        bh = affs_bread(sb, bm->bm_key);

        if (!bh)

            goto err_bh_read;

        sbi->s_bmap_bh = bh;

        sbi->s_last_bmap = bmap;

    }

​

    mask = 1 << (bit & 31);

    data = (__be32 *)bh->b_data + bit / 32 + 1;

​

    /* mark block free */

    tmp = be32_to_cpu(*data);

    if (tmp & mask)

        goto err_free;

    *data = cpu_to_be32(tmp | mask);

​

    /* fix checksum */

    tmp = be32_to_cpu(*(__be32 *)bh->b_data);

    *(__be32 *)bh->b_data = cpu_to_be32(tmp - mask);

​

    mark_buffer_dirty(bh);

    affs_mark_sb_dirty(sb);

    bm->bm_free++;

​

    mutex_unlock(&sbi->s_bmlock);

    return;

​

err_free:

    affs_warning(sb,"affs_free_block","Trying to free block %u which is already free", block);

    mutex_unlock(&sbi->s_bmlock);

    return;