लिनक्स/linux-0.01.tar/fs/inode.c
दिखावट
< लिनक्स | linux-0.01.tar
#include <string.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 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>1) { inode->i_count--; return; } repeat: 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; } static volatile int last_allocated_inode = 0; struct m_inode * get_empty_inode(void) { struct m_inode * inode; int inr; while (1) { inode = NULL; inr = last_allocated_inode; do { if (!inode_table[inr].i_count) { inode = inr + inode_table; break; } inr++; if (inr>=NR_INODE) inr=0; } while (inr != last_allocated_inode); if (!inode) { for (inr=0 ; inr<NR_INODE ; inr++) printk("%04x: %6d\t",inode_table[inr].i_dev, inode_table[inr].i_num); panic("No free inodes in mem"); } last_allocated_inode = inr; wait_on_inode(inode); while (inode->i_dirt) { write_inode(inode); wait_on_inode(inode); } if (!inode->i_count) break; } 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 (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); sb=get_super(inode->i_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"); *(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); sb=get_super(inode->i_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"); ((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); }