74 lines
1.4 KiB
C
74 lines
1.4 KiB
C
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#include "types.h"
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#include "param.h"
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#include "x86.h"
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#include "mmu.h"
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#include "proc.h"
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#include "defs.h"
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#include "spinlock.h"
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#include "buf.h"
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#include "fs.h"
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#include "fsvar.h"
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// these are inodes currently in use
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// an entry is free if count == 0
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struct inode inode[NINODE];
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struct spinlock inode_table_lock;
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struct inode *
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iget(uint dev, uint inum)
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{
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struct inode *ip, *nip = 0;
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struct dinode *dip;
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struct buf *bp;
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acquire(&inode_table_lock);
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loop:
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for(ip = &inode[0]; ip < &inode[NINODE]; ip++){
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if(ip->count > 0 && ip->dev == dev && ip->inum == inum){
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if(ip->busy){
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sleep(ip, &inode_table_lock);
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goto loop;
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}
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ip->count++;
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release(&inode_table_lock);
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return ip;
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}
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if(nip == 0 && ip->count == 0)
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nip = ip;
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}
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if(nip == 0)
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panic("out of inodes");
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nip->dev = dev;
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nip->inum = inum;
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nip->count = 1;
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nip->busy = 1;
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release(&inode_table_lock);
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bp = bread(dev, inum / IPB + 2);
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dip = &((struct dinode *)(bp->data))[inum % IPB];
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nip->type = dip->type;
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nip->nlink = dip->nlink;
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nip->size = dip->size;
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memmove(nip->addrs, dip->addrs, sizeof(nip->addrs));
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cprintf("bn %d off %d\n", inum / IPB + 2, (unsigned)dip - (unsigned)bp->data);
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brelse(bp);
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return nip;
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}
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void
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iput(struct inode *ip)
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{
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acquire(&inode_table_lock);
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ip->count -= 1;
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ip->busy = 0;
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wakeup(ip);
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release(&inode_table_lock);
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}
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