ADD file via upload

3 years ago · 80c3cf4ebe
parent 05d6f2baba
commit 80c3cf4ebe
1 changed files with 340 additions and 0 deletions
--- a/cur/linux/fs/inode.c
+++ b/cur/linux/fs/inode.c
@ -0,0 +1,340 @@
+/*
+ *  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");
+	__asm__ volatile ("cld");   /* by wyj */
+	*(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");
+	__asm__ volatile ("cld");   /* by wyj */
+	((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);
+}