/* *  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> static 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);}