// SPDX-License-Identifier: GPL-2.0/* *  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/buffer_head.h>#include <linux/bitops.h>#include <linux/sched.h> static DEFINE_SPINLOCK(bitmap_lock); /* * bitmap consists of blocks filled with 16bit words * bit set == busy, bit clear == free * endianness is a mess, but for counting zero bits it really doesn't matter... */static __u32 count_free(struct buffer_head *map[], unsigned blocksize, __u32 numbits){	__u32 sum = 0;	unsigned blocks = DIV_ROUND_UP(numbits, blocksize * 8); 	while (blocks--) {		unsigned words = blocksize / 2;		__u16 *p = (__u16 *)(*map++)->b_data;		while (words--)			sum += 16 - hweight16(*p++);	} 	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];	spin_lock(&bitmap_lock);	if (!minix_test_and_clear_bit(bit, bh->b_data))		printk("minix_free_block (%s:%lu): bit already cleared\n",		       sb->s_id, block);	spin_unlock(&bitmap_lock);	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; 		spin_lock(&bitmap_lock);		j = minix_find_first_zero_bit(bh->b_data, bits_per_zone);		if (j < bits_per_zone) {			minix_set_bit(j, bh->b_data);			spin_unlock(&bitmap_lock);			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;		}		spin_unlock(&bitmap_lock);	}	return 0;} unsigned long minix_count_free_blocks(struct super_block *sb){	struct minix_sb_info *sbi = minix_sb(sb);	u32 bits = sbi->s_nzones - sbi->s_firstdatazone + 1; 	return (count_free(sbi->s_zmap, sb->s_blocksize, bits)		<< 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");		return;	}	bit = ino & ((1<<k) - 1);	ino >>= k;	if (ino >= sbi->s_imap_blocks) {		printk("minix_free_inode: nonexistent imap in superblock\n");		return;	} 	minix_clear_inode(inode);	/* clear on-disk copy */ 	bh = sbi->s_imap[ino];	spin_lock(&bitmap_lock);	if (!minix_test_and_clear_bit(bit, bh->b_data))		printk("minix_free_inode: bit %lu already cleared\n", bit);	spin_unlock(&bitmap_lock);	mark_buffer_dirty(bh);} struct inode *minix_new_inode(const struct inode *dir, umode_t mode){	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)		return ERR_PTR(-ENOMEM);	j = bits_per_zone;	bh = NULL;	spin_lock(&bitmap_lock);	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) {		spin_unlock(&bitmap_lock);		iput(inode);		return ERR_PTR(-ENOSPC);	}	if (minix_test_and_set_bit(j, bh->b_data)) {	/* shouldn't happen */		spin_unlock(&bitmap_lock);		printk("minix_new_inode: bit already set\n");		iput(inode);		return ERR_PTR(-ENOSPC);	}	spin_unlock(&bitmap_lock);	mark_buffer_dirty(bh);	j += i * bits_per_zone;	if (!j || j > sbi->s_ninodes) {		iput(inode);		return ERR_PTR(-EFSCORRUPTED);	}	inode_init_owner(&nop_mnt_idmap, inode, dir, mode);	inode->i_ino = j;	simple_inode_init_ts(inode);	inode->i_blocks = 0;	memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u));	insert_inode_hash(inode);	mark_inode_dirty(inode); 	return inode;} unsigned long minix_count_free_inodes(struct super_block *sb){	struct minix_sb_info *sbi = minix_sb(sb);	u32 bits = sbi->s_ninodes + 1; 	return count_free(sbi->s_imap, sb->s_blocksize, bits);}