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* linux/fs/inode.c
*
* (C) 1991 Linus Torvalds
*/
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <asm/system.h>
struct inode inode_table[NR_INODE]={{0,},};
static inline void wait_on_inode(struct inode * inode)
{
cli();
while (inode->i_lock)
sleep_on(&inode->i_wait);
sti();
}
static inline void lock_inode(struct inode * inode)
{
cli();
while (inode->i_lock)
sleep_on(&inode->i_wait);
inode->i_lock=1;
sti();
}
static inline void unlock_inode(struct inode * inode)
{
inode->i_lock=0;
wake_up(&inode->i_wait);
}
static void write_inode(struct inode * inode)
{
if (!inode->i_dirt)
return;
inode->i_dirt = 0;
lock_inode(inode);
if (inode->i_dev && inode->i_sb &&
inode->i_sb->s_op && inode->i_sb->s_op->write_inode)
inode->i_sb->s_op->write_inode(inode);
unlock_inode(inode);
}
static void read_inode(struct inode * inode)
{
lock_inode(inode);
if (inode->i_sb && inode->i_sb->s_op && inode->i_sb->s_op->read_inode)
inode->i_sb->s_op->read_inode(inode);
unlock_inode(inode);
}
/*
* bmap is needed for demand-loading and paging: if this function
* doesn't exist for a filesystem, then those things are impossible:
* executables cannot be run from the filesystem etc...
*
* This isn't as bad as it sounds: the read-routines might still work,
* so the filesystem would be otherwise ok (for example, you might have
* a DOS filesystem, which doesn't lend itself to bmap very well, but
* you could still transfer files to/from the filesystem)
*/
int bmap(struct inode * inode, int block)
{
if (inode->i_op && inode->i_op->bmap)
return inode->i_op->bmap(inode,block);
return 0;
}
void invalidate_inodes(int dev)
{
int i;
struct 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");
continue;
}
inode->i_dev = inode->i_dirt = 0;
}
}
}
void sync_inodes(void)
{
int i;
struct 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);
}
}
void iput(struct inode * inode)
{
if (!inode)
return;
wait_on_inode(inode);
if (!inode->i_count) {
printk("iput: trying to free free inode\n");
printk("device %04x, inode %d, mode=%07o\n",inode->i_rdev,
inode->i_ino,inode->i_mode);
return;
}
if (inode->i_pipe) {
wake_up(&inode->i_wait);
wake_up(&inode->i_wait2);
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;
}
repeat:
if (inode->i_count>1) {
inode->i_count--;
return;
}
if (!inode->i_nlink) {
if (inode->i_sb && inode->i_sb->s_op && inode->i_sb->s_op->put_inode)
inode->i_sb->s_op->put_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 inode * get_empty_inode(void)
{
struct inode * inode;
static struct 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: %d (%o)) ",inode_table[i].i_dev,
inode_table[i].i_ino,inode_table[i].i_mode);
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 inode * get_pipe_inode(void)
{
struct 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 inode * iget(int dev,int nr)
{
struct 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_ino != nr) {
inode++;
continue;
}
wait_on_inode(inode);
if (inode->i_dev != dev || inode->i_ino != 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_covered==inode)
break;
if (i >= NR_SUPER) {
printk("Mounted inode hasn't got sb\n");
if (empty)
iput(empty);
return inode;
}
iput(inode);
if (!(inode = super_block[i].s_mounted))
printk("iget: mounted dev has no rootinode\n");
else {
inode->i_count++;
wait_on_inode(inode);
}
}
if (empty)
iput(empty);
return inode;
}
if (!empty)
return (NULL);
inode = empty;
if (!(inode->i_sb = get_super(dev))) {
printk("iget: gouldn't get super-block\n\t");
iput(inode);
return NULL;
}
inode->i_dev = dev;
inode->i_ino = nr;
read_inode(inode);
return inode;
}
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