/* *  linux/fs/inode.c * *  (C) 1991  Linus Torvalds */#include <string.h> #include <sys/stat.h>#include <linux/sched.h>#include <linux/kernel.h>#include <linux/mm.h>#include <asm/system.h>struct m_inode inode_table[NR_INODE]={{0,},};static void read_inode(struct m_inode * inode);static void write_inode(struct m_inode * inode);static inline void wait_on_inode(struct m_inode * inode){	cli();	while (inode->i_lock)		sleep_on(&inode->i_wait);	sti();}static inline void lock_inode(struct m_inode * inode){	cli();	while (inode->i_lock)		sleep_on(&inode->i_wait);	inode->i_lock=1;	sti();}static inline void unlock_inode(struct m_inode * inode){	inode->i_lock=0;	wake_up(&inode->i_wait);}void invalidate_inodes(int dev){	int i;	struct m_inode * inode;	inode = 0+inode_table;	for(i=0 ; i<NR_INODE ; i++,inode++) {		wait_on_inode(inode);		if (inode->i_dev == dev) {			if (inode->i_count)				printk("inode in use on removed disk\n\r");			inode->i_dev = inode->i_dirt = 0;		}	}}void sync_inodes(void){	int i;	struct m_inode * inode;	inode = 0+inode_table;	for(i=0 ; i<NR_INODE ; i++,inode++) {		wait_on_inode(inode);		if (inode->i_dirt && !inode->i_pipe)			write_inode(inode);	}}static int _bmap(struct m_inode * inode,int block,int create){	struct buffer_head * bh;	int i;	if (block<0)		panic("_bmap: block<0");	if (block >= 7+512+512*512)		panic("_bmap: block>big");	if (block<7) {		if (create && !inode->i_zone[block])			if ((inode->i_zone[block]=new_block(inode->i_dev))) {				inode->i_ctime=CURRENT_TIME;				inode->i_dirt=1;			}		return inode->i_zone[block];	}	block -= 7;	if (block<512) {		if (create && !inode->i_zone[7])			if ((inode->i_zone[7]=new_block(inode->i_dev))) {				inode->i_dirt=1;				inode->i_ctime=CURRENT_TIME;			}		if (!inode->i_zone[7])			return 0;		if (!(bh = bread(inode->i_dev,inode->i_zone[7])))			return 0;		i = ((unsigned short *) (bh->b_data))[block];		if (create && !i)			if ((i=new_block(inode->i_dev))) {				((unsigned short *) (bh->b_data))[block]=i;				bh->b_dirt=1;			}		brelse(bh);		return i;	}	block -= 512;	if (create && !inode->i_zone[8])		if ((inode->i_zone[8]=new_block(inode->i_dev))) {			inode->i_dirt=1;			inode->i_ctime=CURRENT_TIME;		}	if (!inode->i_zone[8])		return 0;	if (!(bh=bread(inode->i_dev,inode->i_zone[8])))		return 0;	i = ((unsigned short *)bh->b_data)[block>>9];	if (create && !i)		if ((i=new_block(inode->i_dev))) {			((unsigned short *) (bh->b_data))[block>>9]=i;			bh->b_dirt=1;		}	brelse(bh);	if (!i)		return 0;	if (!(bh=bread(inode->i_dev,i)))		return 0;	i = ((unsigned short *)bh->b_data)[block&511];	if (create && !i)		if ((i=new_block(inode->i_dev))) {			((unsigned short *) (bh->b_data))[block&511]=i;			bh->b_dirt=1;		}	brelse(bh);	return i;}int bmap(struct m_inode * inode,int block){	return _bmap(inode,block,0);}int create_block(struct m_inode * inode, int block){	return _bmap(inode,block,1);}		void iput(struct m_inode * inode){	if (!inode)		return;	wait_on_inode(inode);	if (!inode->i_count)		panic("iput: trying to free free inode");	if (inode->i_pipe) {		wake_up(&inode->i_wait);		if (--inode->i_count)			return;		free_page(inode->i_size);		inode->i_count=0;		inode->i_dirt=0;		inode->i_pipe=0;		return;	}	if (!inode->i_dev) {		inode->i_count--;		return;	}	if (S_ISBLK(inode->i_mode)) {		sync_dev(inode->i_zone[0]);		wait_on_inode(inode);	}repeat:	if (inode->i_count>1) {		inode->i_count--;		return;	}	if (!inode->i_nlinks) {		truncate(inode);		free_inode(inode);		return;	}	if (inode->i_dirt) {		write_inode(inode);	/* we can sleep - so do again */		wait_on_inode(inode);		goto repeat;	}	inode->i_count--;	return;}struct m_inode * get_empty_inode(void){	struct m_inode * inode;	static struct m_inode * last_inode = inode_table;	int i;	do {		inode = NULL;		for (i = NR_INODE; i ; i--) {			if (++last_inode >= inode_table + NR_INODE)				last_inode = inode_table;			if (!last_inode->i_count) {				inode = last_inode;				if (!inode->i_dirt && !inode->i_lock)					break;			}		}		if (!inode) {			for (i=0 ; i<NR_INODE ; i++)				printk("%04x: %6d\t",inode_table[i].i_dev,					inode_table[i].i_num);			panic("No free inodes in mem");		}		wait_on_inode(inode);		while (inode->i_dirt) {			write_inode(inode);			wait_on_inode(inode);		}	} while (inode->i_count);	memset(inode,0,sizeof(*inode));	inode->i_count = 1;	return inode;}struct m_inode * get_pipe_inode(void){	struct m_inode * inode;	if (!(inode = get_empty_inode()))		return NULL;	if (!(inode->i_size=get_free_page())) {		inode->i_count = 0;		return NULL;	}	inode->i_count = 2;	/* sum of readers/writers */	PIPE_HEAD(*inode) = PIPE_TAIL(*inode) = 0;	inode->i_pipe = 1;	return inode;}struct m_inode * iget(int dev,int nr){	struct m_inode * inode, * empty;	if (!dev)		panic("iget with dev==0");	empty = get_empty_inode();	inode = inode_table;	while (inode < NR_INODE+inode_table) {		if (inode->i_dev != dev || inode->i_num != nr) {			inode++;			continue;		}		wait_on_inode(inode);		if (inode->i_dev != dev || inode->i_num != nr) {			inode = inode_table;			continue;		}		inode->i_count++;		if (inode->i_mount) {			int i;			for (i = 0 ; i<NR_SUPER ; i++)				if (super_block[i].s_imount==inode)					break;			if (i >= NR_SUPER) {				printk("Mounted inode hasn't got sb\n");				if (empty)					iput(empty);				return inode;			}			iput(inode);			dev = super_block[i].s_dev;			nr = ROOT_INO;			inode = inode_table;			continue;		}		if (empty)			iput(empty);		return inode;	}	if (!empty)		return (NULL);	inode=empty;	inode->i_dev = dev;	inode->i_num = nr;	read_inode(inode);	return inode;}static void read_inode(struct m_inode * inode){	struct super_block * sb;	struct buffer_head * bh;	int block;	lock_inode(inode);	if (!(sb=get_super(inode->i_dev)))		panic("trying to read inode without dev");	block = 2 + sb->s_imap_blocks + sb->s_zmap_blocks +		(inode->i_num-1)/INODES_PER_BLOCK;	if (!(bh=bread(inode->i_dev,block)))		panic("unable to read i-node block");	*(struct d_inode *)inode =		((struct d_inode *)bh->b_data)			[(inode->i_num-1)%INODES_PER_BLOCK];	brelse(bh);	unlock_inode(inode);}static void write_inode(struct m_inode * inode){	struct super_block * sb;	struct buffer_head * bh;	int block;	lock_inode(inode);	if (!inode->i_dirt || !inode->i_dev) {		unlock_inode(inode);		return;	}	if (!(sb=get_super(inode->i_dev)))		panic("trying to write inode without device");	block = 2 + sb->s_imap_blocks + sb->s_zmap_blocks +		(inode->i_num-1)/INODES_PER_BLOCK;	if (!(bh=bread(inode->i_dev,block)))		panic("unable to read i-node block");	((struct d_inode *)bh->b_data)		[(inode->i_num-1)%INODES_PER_BLOCK] =			*(struct d_inode *)inode;	bh->b_dirt=1;	inode->i_dirt=0;	brelse(bh);	unlock_inode(inode);}