लिनक्स/linux-0.01.tar/fs/truncate.c
पठन सेटिंग्स
< लिनक्स | linux-0.01.tar
/* * 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); }