diff options
Diffstat (limited to 'linux/fs/inode.c')
| -rw-r--r-- | linux/fs/inode.c | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/linux/fs/inode.c b/linux/fs/inode.c new file mode 100644 index 0000000..d06ff90 --- /dev/null +++ b/linux/fs/inode.c @@ -0,0 +1,288 @@ +#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); +} |