/* *  linux/fs/bitmap.c * *  (C) 1991  Linus Torvalds *//* bitmap.c contains the code that handles the inode and block bitmaps */#include <string.h>#include <linux/sched.h>#include <linux/kernel.h>#define clear_block(addr) \__asm__("cld\n\t" \	"rep\n\t" \	"stosl" \	::"a" (0),"c" (BLOCK_SIZE/4),"D" ((long) (addr)):"cx","di")#define set_bit(nr,addr) ({\register int res __asm__("ax"); \__asm__ __volatile__("btsl %2,%3\n\tsetb %%al": \"=a" (res):"0" (0),"r" (nr),"m" (*(addr))); \res;})#define clear_bit(nr,addr) ({\register int res __asm__("ax"); \__asm__ __volatile__("btrl %2,%3\n\tsetnb %%al": \"=a" (res):"0" (0),"r" (nr),"m" (*(addr))); \res;})#define find_first_zero(addr) ({ \int __res; \__asm__("cld\n" \	"1:\tlodsl\n\t" \	"notl %%eax\n\t" \	"bsfl %%eax,%%edx\n\t" \	"je 2f\n\t" \	"addl %%edx,%%ecx\n\t" \	"jmp 3f\n" \	"2:\taddl $32,%%ecx\n\t" \	"cmpl $8192,%%ecx\n\t" \	"jl 1b\n" \	"3:" \	:"=c" (__res):"c" (0),"S" (addr):"ax","dx","si"); \__res;})void free_block(int dev, int block){	struct super_block * sb;	struct buffer_head * bh;	if (!(sb = get_super(dev)))		panic("trying to free block on nonexistent device");	if (block < sb->s_firstdatazone || block >= sb->s_nzones)		panic("trying to free block not in datazone");	bh = get_hash_table(dev,block);	if (bh) {		if (bh->b_count != 1) {			printk("trying to free block (%04x:%d), count=%d\n",				dev,block,bh->b_count);			return;		}		bh->b_dirt=0;		bh->b_uptodate=0;		brelse(bh);	}	block -= sb->s_firstdatazone - 1 ;	if (clear_bit(block&8191,sb->s_zmap[block/8192]->b_data)) {		printk("block (%04x:%d) ",dev,block+sb->s_firstdatazone-1);		panic("free_block: bit already cleared");	}	sb->s_zmap[block/8192]->b_dirt = 1;}int new_block(int dev){	struct buffer_head * bh;	struct super_block * sb;	int i,j;	if (!(sb = get_super(dev)))		panic("trying to get new block from nonexistant device");	j = 8192;	for (i=0 ; i<8 ; i++)		if (bh=sb->s_zmap[i])			if ((j=find_first_zero(bh->b_data))<8192)				break;	if (i>=8 || !bh || j>=8192)		return 0;	if (set_bit(j,bh->b_data))		panic("new_block: bit already set");	bh->b_dirt = 1;	j += i*8192 + sb->s_firstdatazone-1;	if (j >= sb->s_nzones)		return 0;	if (!(bh=getblk(dev,j)))		panic("new_block: cannot get block");	if (bh->b_count != 1)		panic("new block: count is != 1");	clear_block(bh->b_data);	bh->b_uptodate = 1;	bh->b_dirt = 1;	brelse(bh);	return j;}void free_inode(struct m_inode * inode){	struct super_block * sb;	struct buffer_head * bh;	if (!inode)		return;	if (!inode->i_dev) {		memset(inode,0,sizeof(*inode));		return;	}	if (inode->i_count>1) {		printk("trying to free inode with count=%d\n",inode->i_count);		panic("free_inode");	}	if (inode->i_nlinks)		panic("trying to free inode with links");	if (!(sb = get_super(inode->i_dev)))		panic("trying to free inode on nonexistent device");	if (inode->i_num < 1 || inode->i_num > sb->s_ninodes)		panic("trying to free inode 0 or nonexistant inode");	if (!(bh=sb->s_imap[inode->i_num>>13]))		panic("nonexistent imap in superblock");	if (clear_bit(inode->i_num&8191,bh->b_data))		printk("free_inode: bit already cleared.\n\r");	bh->b_dirt = 1;	memset(inode,0,sizeof(*inode));}struct m_inode * new_inode(int dev){	struct m_inode * inode;	struct super_block * sb;	struct buffer_head * bh;	int i,j;	if (!(inode=get_empty_inode()))		return NULL;	if (!(sb = get_super(dev)))		panic("new_inode with unknown device");	j = 8192;	for (i=0 ; i<8 ; i++)		if (bh=sb->s_imap[i])			if ((j=find_first_zero(bh->b_data))<8192)				break;	if (!bh || j >= 8192 || j+i*8192 > sb->s_ninodes) {		iput(inode);		return NULL;	}	if (set_bit(j,bh->b_data))		panic("new_inode: bit already set");	bh->b_dirt = 1;	inode->i_count=1;	inode->i_nlinks=1;	inode->i_dev=dev;	inode->i_uid=current->euid;	inode->i_gid=current->egid;	inode->i_dirt=1;	inode->i_num = j + i*8192;	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;	return inode;}