add directory kernel
This commit is contained in:
gohigh
288
kernel/0.00/linux-0.01/fs/inode.c
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288
kernel/0.00/linux-0.01/fs/inode.c
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#include <string.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <asm/system.h>
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struct m_inode inode_table[NR_INODE]={{0,},};
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static void read_inode(struct m_inode * inode);
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static void write_inode(struct m_inode * inode);
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static inline void wait_on_inode(struct m_inode * inode)
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{
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cli();
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while (inode->i_lock)
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sleep_on(&inode->i_wait);
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sti();
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}
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static inline void lock_inode(struct m_inode * inode)
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{
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cli();
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while (inode->i_lock)
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sleep_on(&inode->i_wait);
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inode->i_lock=1;
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sti();
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}
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static inline void unlock_inode(struct m_inode * inode)
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{
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inode->i_lock=0;
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wake_up(&inode->i_wait);
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}
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void sync_inodes(void)
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{
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int i;
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struct m_inode * inode;
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inode = 0+inode_table;
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for(i=0 ; i<NR_INODE ; i++,inode++) {
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wait_on_inode(inode);
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if (inode->i_dirt && !inode->i_pipe)
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write_inode(inode);
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}
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}
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static int _bmap(struct m_inode * inode,int block,int create)
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{
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struct buffer_head * bh;
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int i;
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if (block<0)
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panic("_bmap: block<0");
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if (block >= 7+512+512*512)
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panic("_bmap: block>big");
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if (block<7) {
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if (create && !inode->i_zone[block])
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if (inode->i_zone[block]=new_block(inode->i_dev)) {
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inode->i_ctime=CURRENT_TIME;
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inode->i_dirt=1;
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}
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return inode->i_zone[block];
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}
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block -= 7;
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if (block<512) {
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if (create && !inode->i_zone[7])
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if (inode->i_zone[7]=new_block(inode->i_dev)) {
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inode->i_dirt=1;
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inode->i_ctime=CURRENT_TIME;
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}
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if (!inode->i_zone[7])
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return 0;
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if (!(bh = bread(inode->i_dev,inode->i_zone[7])))
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return 0;
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i = ((unsigned short *) (bh->b_data))[block];
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if (create && !i)
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if (i=new_block(inode->i_dev)) {
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((unsigned short *) (bh->b_data))[block]=i;
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bh->b_dirt=1;
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}
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brelse(bh);
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return i;
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}
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block -= 512;
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if (create && !inode->i_zone[8])
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if (inode->i_zone[8]=new_block(inode->i_dev)) {
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inode->i_dirt=1;
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inode->i_ctime=CURRENT_TIME;
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}
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if (!inode->i_zone[8])
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return 0;
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if (!(bh=bread(inode->i_dev,inode->i_zone[8])))
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return 0;
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i = ((unsigned short *)bh->b_data)[block>>9];
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if (create && !i)
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if (i=new_block(inode->i_dev)) {
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((unsigned short *) (bh->b_data))[block>>9]=i;
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bh->b_dirt=1;
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}
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brelse(bh);
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if (!i)
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return 0;
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if (!(bh=bread(inode->i_dev,i)))
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return 0;
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i = ((unsigned short *)bh->b_data)[block&511];
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if (create && !i)
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if (i=new_block(inode->i_dev)) {
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((unsigned short *) (bh->b_data))[block&511]=i;
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bh->b_dirt=1;
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}
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brelse(bh);
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return i;
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}
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int bmap(struct m_inode * inode,int block)
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{
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return _bmap(inode,block,0);
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}
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int create_block(struct m_inode * inode, int block)
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{
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return _bmap(inode,block,1);
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}
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void iput(struct m_inode * inode)
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{
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if (!inode)
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return;
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wait_on_inode(inode);
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if (!inode->i_count)
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panic("iput: trying to free free inode");
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if (inode->i_pipe) {
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wake_up(&inode->i_wait);
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if (--inode->i_count)
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return;
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free_page(inode->i_size);
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inode->i_count=0;
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inode->i_dirt=0;
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inode->i_pipe=0;
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return;
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}
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if (!inode->i_dev || inode->i_count>1) {
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inode->i_count--;
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return;
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}
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repeat:
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if (!inode->i_nlinks) {
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truncate(inode);
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free_inode(inode);
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return;
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}
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if (inode->i_dirt) {
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write_inode(inode); /* we can sleep - so do again */
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wait_on_inode(inode);
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goto repeat;
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}
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inode->i_count--;
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return;
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}
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static volatile int last_allocated_inode = 0;
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struct m_inode * get_empty_inode(void)
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{
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struct m_inode * inode;
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int inr;
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while (1) {
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inode = NULL;
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inr = last_allocated_inode;
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do {
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if (!inode_table[inr].i_count) {
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inode = inr + inode_table;
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break;
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}
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inr++;
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if (inr>=NR_INODE)
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inr=0;
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} while (inr != last_allocated_inode);
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if (!inode) {
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for (inr=0 ; inr<NR_INODE ; inr++)
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printk("%04x: %6d\t",inode_table[inr].i_dev,
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inode_table[inr].i_num);
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panic("No free inodes in mem");
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}
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last_allocated_inode = inr;
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wait_on_inode(inode);
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while (inode->i_dirt) {
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write_inode(inode);
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wait_on_inode(inode);
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}
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if (!inode->i_count)
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break;
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}
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memset(inode,0,sizeof(*inode));
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inode->i_count = 1;
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return inode;
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}
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struct m_inode * get_pipe_inode(void)
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{
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struct m_inode * inode;
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if (!(inode = get_empty_inode()))
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return NULL;
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if (!(inode->i_size=get_free_page())) {
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inode->i_count = 0;
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return NULL;
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}
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inode->i_count = 2; /* sum of readers/writers */
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PIPE_HEAD(*inode) = PIPE_TAIL(*inode) = 0;
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inode->i_pipe = 1;
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return inode;
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}
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struct m_inode * iget(int dev,int nr)
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{
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struct m_inode * inode, * empty;
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if (!dev)
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panic("iget with dev==0");
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empty = get_empty_inode();
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inode = inode_table;
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while (inode < NR_INODE+inode_table) {
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if (inode->i_dev != dev || inode->i_num != nr) {
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inode++;
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continue;
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}
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wait_on_inode(inode);
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if (inode->i_dev != dev || inode->i_num != nr) {
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inode = inode_table;
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continue;
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}
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inode->i_count++;
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if (empty)
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iput(empty);
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return inode;
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}
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if (!empty)
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return (NULL);
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inode=empty;
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inode->i_dev = dev;
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inode->i_num = nr;
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read_inode(inode);
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return inode;
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}
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static void read_inode(struct m_inode * inode)
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{
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struct super_block * sb;
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struct buffer_head * bh;
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int block;
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lock_inode(inode);
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sb=get_super(inode->i_dev);
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block = 2 + sb->s_imap_blocks + sb->s_zmap_blocks +
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(inode->i_num-1)/INODES_PER_BLOCK;
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if (!(bh=bread(inode->i_dev,block)))
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panic("unable to read i-node block");
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*(struct d_inode *)inode =
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((struct d_inode *)bh->b_data)
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[(inode->i_num-1)%INODES_PER_BLOCK];
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brelse(bh);
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unlock_inode(inode);
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}
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static void write_inode(struct m_inode * inode)
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{
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struct super_block * sb;
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struct buffer_head * bh;
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int block;
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lock_inode(inode);
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sb=get_super(inode->i_dev);
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block = 2 + sb->s_imap_blocks + sb->s_zmap_blocks +
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(inode->i_num-1)/INODES_PER_BLOCK;
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if (!(bh=bread(inode->i_dev,block)))
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panic("unable to read i-node block");
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((struct d_inode *)bh->b_data)
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[(inode->i_num-1)%INODES_PER_BLOCK] =
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*(struct d_inode *)inode;
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bh->b_dirt=1;
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inode->i_dirt=0;
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brelse(bh);
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unlock_inode(inode);
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}
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