Imbus/xv6-riscv-kernel
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Replace I_BUSY with sleep locks

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This commit is contained in:
Frans Kaashoek 2016-09-11 20:59:57 -04:00
parent 2adb7c21dc
commit dec637bc59
7 changed files with 20 additions and 21 deletions
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27
fs.c
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@ -135,9 +135,7 @@ bfree(int dev, uint b)
//
// * Locked: file system code may only examine and modify
// the information in an inode and its content if it
// has first locked the inode. The I_BUSY flag indicates
// that the inode is locked. ilock() sets I_BUSY,
// while iunlock clears it.
// has first locked the inode.
//
// Thus a typical sequence is:
// ip = iget(dev, inum)
@ -165,7 +163,13 @@ struct {
void
iinit(int dev)
{
int i = 0;
initlock(&icache.lock, "icache");
for(i = 0; i < NINODE; i++) {
initsleeplock(&icache.inode[i].lock, "inode");
}
readsb(dev, &sb);
cprintf("sb: size %d nblocks %d ninodes %d nlog %d logstart %d\
inodestart %d bmap start %d\n", sb.size, sb.nblocks,
@ -277,11 +281,7 @@ ilock(struct inode *ip)
if(ip == 0 || ip->ref < 1)
panic("ilock");
acquire(&icache.lock);
while(ip->flags & I_BUSY)
sleep(ip, &icache.lock);
ip->flags |= I_BUSY;
release(&icache.lock);
acquiresleep(&ip->lock);
if(!(ip->flags & I_VALID)){
bp = bread(ip->dev, IBLOCK(ip->inum, sb));
@ -303,13 +303,10 @@ ilock(struct inode *ip)
void
iunlock(struct inode *ip)
{
if(ip == 0 || !(ip->flags & I_BUSY) || ip->ref < 1)
if(ip == 0 || !holdingsleep(&ip->lock) || ip->ref < 1)
panic("iunlock");
acquire(&icache.lock);
ip->flags &= ~I_BUSY;
wakeup(ip);
release(&icache.lock);
releasesleep(&ip->lock);
}
// Drop a reference to an in-memory inode.
@ -325,16 +322,12 @@ iput(struct inode *ip)
acquire(&icache.lock);
if(ip->ref == 1 && (ip->flags & I_VALID) && ip->nlink == 0){
// inode has no links and no other references: truncate and free.
if(ip->flags & I_BUSY)
panic("iput busy");
ip->flags |= I_BUSY;
release(&icache.lock);
itrunc(ip);
ip->type = 0;
iupdate(ip);
acquire(&icache.lock);
ip->flags = 0;
wakeup(ip);
}
ip->ref--;
release(&icache.lock);