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发信人: GyeaonWoo (柏林恋人), 信区: Linux
标 题: Linus's Linux--fs/super.c
发信站: 荔园晨风BBS站 (Mon Aug 25 20:04:13 2003), 站内信件
/*
* super.c contains code to handle the super-block tables.
*/
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/kernel.h>
/* set_bit uses setb, as gas doesn't recognize setc */
#define set_bit(bitnr,addr) ({ \
register int __res __asm__("ax"); \
__asm__("bt %2,%3;setb %%al":"=a" (__res):"a" (0),"r" (bitnr),"m"
(*(addr))); \
__res; })
struct super_block super_block[NR_SUPER];
struct super_block * do_mount(int dev)
{
struct super_block * p;
struct buffer_head * bh;
int i,block;
for(p = &super_block[0] ; p < &super_block[NR_SUPER] ; p++ )
if (!(p->s_dev))
break;
p->s_dev = -1; /* mark it in use */
if (p >= &super_block[NR_SUPER])
return NULL;
if (!(bh = bread(dev,1)))
return NULL;
*p = *((struct super_block *) bh->b_data);
brelse(bh);
if (p->s_magic != SUPER_MAGIC) {
p->s_dev = 0;
return NULL;
}
for (i=0;i<I_MAP_SLOTS;i++)
p->s_imap[i] = NULL;
for (i=0;i<Z_MAP_SLOTS;i++)
p->s_zmap[i] = NULL;
block=2;
for (i=0 ; i < p->s_imap_blocks ; i++)
if (p->s_imap[i]=bread(dev,block))
block++;
else
break;
for (i=0 ; i < p->s_zmap_blocks ; i++)
if (p->s_zmap[i]=bread(dev,block))
block++;
else
break;
if (block != 2+p->s_imap_blocks+p->s_zmap_blocks) {
for(i=0;i<I_MAP_SLOTS;i++)
brelse(p->s_imap[i]);
for(i=0;i<Z_MAP_SLOTS;i++)
brelse(p->s_zmap[i]);
p->s_dev=0;
return NULL;
}
p->s_imap[0]->b_data[0] |= 1;
p->s_zmap[0]->b_data[0] |= 1;
p->s_dev = dev;
p->s_isup = NULL;
p->s_imount = NULL;
p->s_time = 0;
p->s_rd_only = 0;
p->s_dirt = 0;
return p;
}
void mount_root(void)
{
int i,free;
struct super_block * p;
struct m_inode * mi;
if (32 != sizeof (struct d_inode))
panic("bad i-node size");
for(i=0;i<NR_FILE;i++)
file_table[i].f_count=0;
for(p = &super_block[0] ; p < &super_block[NR_SUPER] ; p++)
p->s_dev = 0;
if (!(p=do_mount(ROOT_DEV)))
panic("Unable to mount root");
if (!(mi=iget(ROOT_DEV,1)))
panic("Unable to read root i-node");
mi->i_count += 3 ; /* NOTE! it is logically used 4 times, not 1 */
p->s_isup = p->s_imount = mi;
current->pwd = mi;
current->root = mi;
free=0;
i=p->s_nzones;
while (-- i >= 0)
if (!set_bit(i&8191,p->s_zmap[i>>13]->b_data))
free++;
printk("%d/%d free blocks\n\r",free,p->s_nzones);
free=0;
i=p->s_ninodes+1;
while (-- i >= 0)
if (!set_bit(i&8191,p->s_imap[i>>13]->b_data))
free++;
printk("%d/%d free inodes\n\r",free,p->s_ninodes);
}
--
终于能按照自己的内心写作了
却不能按照一个人的内心生活
花太香,只好梦蝶一场唉唉
※ 来源:·荔园晨风BBS站 bbs.szu.edu.cn·[FROM: 192.168.35.5]
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