static struct buffer_head *get_free_buffer(void)
{
register struct buffer_head *bh;
for (;;) {
bh = bh_lru;
do {
#ifdef CONFIG_FS_EXTERNAL_BUFFER
if (bh->b_count == 0 && !bh->b_dirty && !bh->b_lock && !bh->b_data)
#else
if (bh->b_count == 0 && !bh->b_dirty && !bh->b_lock)
#endif
{
put_last_lru(bh);
return bh;
}
} while((bh = bh->b_next_lru) != NULL);
#if 0
fsync_dev(0);
/* This causes a sleep until another process brelse's */
sleep_on(&bufwait);
#endif
sync_buffers(0, 0);
}
}
struct inode *__iget(register struct super_block *sb,
ino_t inr /*,int crossmntp */ )
{
register struct inode *inode;
debug3("iget called(%x, %d, %d)\n", sb, inr, 0 /* crossmntp */ );
if (!sb)
panic("VFS: iget with sb==NULL");
repeat:
do {
inode = first_inode;
do {
if (inode->i_dev == sb->s_dev && inode->i_ino == inr)
goto found_it;
} while ((inode = inode->i_prev) != first_inode);
debug("iget: getting an empty inode...\n");
} while (!(inode = get_empty_inode()));
debug1("iget: got one... (%x)!\n", empty);
inode->i_sb = sb;
inode->i_dev = sb->s_dev;
inode->i_flags = ((unsigned short int) sb->s_flags);
inode->i_ino = inr;
put_last_lru(inode);
debug("iget: Reading inode\n");
read_inode(inode);
debug("iget: Read it\n");
goto return_it;
found_it:
if (!inode->i_count)
nr_free_inodes--;
inode->i_count++;
wait_on_inode(inode);
if (inode->i_dev != sb->s_dev || inode->i_ino != inr) {
printk("Whee.. inode changed from under us. Tell _.\n");
iput(inode);
goto repeat;
}
if ( /* crossmntp && */ inode->i_mount) {
struct inode *tmp = inode->i_mount;
tmp->i_count++;
iput(inode);
inode = tmp;
wait_on_inode(inode);
}
return_it:
return inode;
}
struct buffer_head *getblk(kdev_t dev, block_t block)
{
register struct buffer_head *bh;
/* If there are too many dirty buffers, we wake up the update process
* now so as to ensure that there are still clean buffers available
* for user processes to use (and dirty) */
do {
bh = get_hash_table(dev, block);
if (bh != NULL) {
if (buffer_clean(bh) && buffer_uptodate(bh))
put_last_lru(bh);
return bh;
}
/* I think the following check is redundant
* So I will remove it for now
*/
} while(find_buffer(dev, block));
/*
* Create a buffer for this job.
*/
bh = get_free_buffer();
/* OK, FINALLY we know that this buffer is the only one of its kind,
* and that it's unused (b_count=0), unlocked (buffer_locked=0), and clean
*/
bh->b_count = 1;
bh->b_dirty = 0;
bh->b_lock = 0;
bh->b_uptodate = 0;
bh->b_dev = dev;
bh->b_blocknr = block;
bh->b_seg = kernel_ds;
return bh;
}
