SysIII/usr/src/uts/vax/os/iget.c

#include "sys/param.h"
#include "sys/systm.h"
#include "sys/sysinfo.h"
#include "sys/mount.h"
#include "sys/dir.h"
#include "sys/user.h"
#include "sys/inode.h"
#include "sys/ino.h"
#include "sys/filsys.h"
#include "sys/buf.h"
#include "sys/var.h"

/*
 * Look up an inode by device,inumber.
 * If it is in core (in the inode structure), honor the locking protocol.
 * If it is not in core, read it in from the specified device.
 * If the inode is mounted on, perform the indicated indirection.
 * In all cases, a pointer to a locked inode structure is returned.
 *
 * printf warning: no inodes -- if the inode structure is full
 * panic: no imt -- if the mounted filesystem is not in the mount table.
 *	"cannot happen"
 */
struct inode *
iget(dev, ino)
dev_t dev;
ino_t ino;
{
	register i;
	register struct inode *ip;
	register struct inode *oip;
	register struct mount *mp;
	struct inode *iread();

	sysinfo.iget++;
loop:
	ip = &inode[0];
	oip = NULL;
	i = v.v_inode;
	do {
		if(ino == ip->i_number && dev == ip->i_dev) {
			goto found;
		}
		if(oip==NULL && ip->i_count==0)
			oip = ip;
		ip++;
	} while(--i);
	ip = oip;
	if(ip == NULL) {
		printf("Inode table overflow\n");
		u.u_error = ENFILE;
		return(NULL);
	}
	ip->i_dev = dev;
	ip->i_number = ino;
	ip->i_flag = ILOCK;
	ip->i_count++;
	ip->i_lastr = 0;
	return(iread(ip));
found:
	if((ip->i_flag&ILOCK) != 0) {
		ip->i_flag |= IWANT;
		sleep((caddr_t)ip, PINOD);
		goto loop;
	}
	if((ip->i_flag&IMOUNT) != 0) {
		for(mp = &mount[0]; mp < (struct mount *)v.ve_mount; mp++)
		if(mp->m_inodp == ip) {
			dev = mp->m_dev;
			ino = ROOTINO;
			goto loop;
		}
		panic("no imt");
	}
	ip->i_count++;
	ip->i_flag |= ILOCK;
	return(ip);
}

struct inode *
iread(ip)
register struct inode *ip;
{
	register char *p1, *p2;
	register struct dinode *dp;
	struct buf *bp;
	unsigned i;

	bp = bread(ip->i_dev, itod(ip->i_number));
	if (u.u_error) {
		brelse(bp);
		iput(ip);
		return(NULL);
	}
	dp = bp->b_un.b_dino;
	dp += itoo(ip->i_number);
	ip->i_mode = dp->di_mode;
	ip->i_nlink = dp->di_nlink;
	ip->i_uid = dp->di_uid;
	ip->i_gid = dp->di_gid;
	ip->i_size = dp->di_size;
	p1 = (char *)ip->i_addr;
	p2 = (char *)dp->di_addr;
	for(i=0; i<NADDR; i++) {
		*p1++ = *p2++;
		*p1++ = *p2++;
		*p1++ = *p2++;
		*p1++ = 0;
	}
	brelse(bp);
	return(ip);
}

/*
 * Decrement reference count of an inode structure.
 * On the last reference, write the inode out and if necessary,
 * truncate and deallocate the file.
 */
iput(ip)
register struct inode *ip;
{

	if(ip->i_count == 1) {
		ip->i_flag |= ILOCK;
		if(ip->i_nlink <= 0) {
			itrunc(ip);
			ip->i_mode = 0;
			ip->i_flag |= IUPD|ICHG;
			ifree(ip->i_dev, ip->i_number);
		}
		if(ip->i_flag&(IACC|IUPD|ICHG))
			iupdat(ip, &time, &time);
		prele(ip);
		ip->i_flag = 0;
		ip->i_number = 0;
		ip->i_count = 0;
		return;
	}
	ip->i_count--;
	prele(ip);
}

/*
 * Update the inode with the current time.
 */
iupdat(ip, ta, tm)
register struct inode *ip;
time_t *ta, *tm;
{
	register struct buf *bp;
	struct dinode *dp;
	register char *p1;
	char *p2;
	unsigned i;

	if(getfs(ip->i_dev)->s_ronly) {
		if(ip->i_flag&(IUPD|ICHG))
			u.u_error = EROFS;
		ip->i_flag &= ~(IACC|IUPD|ICHG);
		return;
	}
	bp = bread(ip->i_dev, itod(ip->i_number));
	if (bp->b_flags & B_ERROR) {
		brelse(bp);
		return;
	}
	dp = bp->b_un.b_dino;
	dp += itoo(ip->i_number);
	dp->di_mode = ip->i_mode;
	dp->di_nlink = ip->i_nlink;
	dp->di_uid = ip->i_uid;
	dp->di_gid = ip->i_gid;
	dp->di_size = ip->i_size;
	p1 = (char *)dp->di_addr;
	p2 = (char *)ip->i_addr;
	if ((ip->i_mode&IFMT)==IFIFO) {
		for (i=0; i<NFADDR; i++) {
			*p1++ = *p2++;
			*p1++ = *p2++;
			*p1++ = *p2++;
			if (*p2++ != 0)
				printf("iaddress > 2^24\n");
		}
		for (; i<NADDR; i++) {
			*p1++ = 0;
			*p1++ = 0;
			*p1++ = 0;
		}
	} else
	for(i=0; i<NADDR; i++) {
		*p1++ = *p2++;
		*p1++ = *p2++;
		*p1++ = *p2++;
		if(*p2++ != 0)
			printf("iaddress > 2^24\n");
	}
	if(ip->i_flag&IACC)
		dp->di_atime = *ta;
	if(ip->i_flag&IUPD)
		dp->di_mtime = *tm;
	if(ip->i_flag&ICHG)
		dp->di_ctime = time;
	ip->i_flag &= ~(IACC|IUPD|ICHG);
	bdwrite(bp);
}

/*
 * Free all the disk blocks associated with the specified inode structure.
 * The blocks of the file are removed in reverse order. This FILO
 * algorithm will tend to maintain
 * a contiguous free list much longer than FIFO.
 */
itrunc(ip)
register struct inode *ip;
{
	register i;
	dev_t dev;
	daddr_t bn;

	i = ip->i_mode & IFMT;
	if (i!=IFREG && i!=IFDIR)
		return;
	dev = ip->i_dev;
	for(i=NADDR-1; i>=0; i--) {
		bn = ip->i_addr[i];
		if(bn == (daddr_t)0)
			continue;
		ip->i_addr[i] = (daddr_t)0;
		switch(i) {

		default:
			free(dev, bn);
			break;

		case NADDR-3:
			tloop(dev, bn, 0, 0);
			break;

		case NADDR-2:
			tloop(dev, bn, 1, 0);
			break;

		case NADDR-1:
			tloop(dev, bn, 1, 1);
		}
	}
	ip->i_size = 0;
	ip->i_flag |= IUPD|ICHG;
}

tloop(dev, bn, f1, f2)
dev_t dev;
daddr_t bn;
{
	register i;
	register struct buf *bp;
	register daddr_t *bap;
	daddr_t nb;

	bp = NULL;
	for(i=NINDIR-1; i>=0; i--) {
		if(bp == NULL) {
			bp = bread(dev, bn);
			if (bp->b_flags & B_ERROR) {
				brelse(bp);
				return;
			}
			bap = bp->b_un.b_daddr;
		}
		nb = bap[i];
		if(nb == (daddr_t)0)
			continue;
		if(f1) {
			brelse(bp);
			bp = NULL;
			tloop(dev, nb, f2, 0);
		} else
			free(dev, nb);
	}
	if(bp != NULL)
		brelse(bp);
	free(dev, bn);
}

/*
 * Make a new file.
 */
struct inode *
maknode(mode)
register mode;
{
	register struct inode *ip;

	ip = ialloc(u.u_pdir->i_dev);
	if(ip == NULL) {
		iput(u.u_pdir);
		return(NULL);
	}
	ip->i_flag |= IACC|IUPD|ICHG;
	if((mode&IFMT) == 0)
		mode |= IFREG;
	ip->i_mode = mode & ~u.u_cmask;
	ip->i_nlink = 1;
	ip->i_uid = u.u_uid;
	ip->i_gid = u.u_gid;
	iupdat(ip, &time, &time);
	wdir(ip);
	return(ip);
}

/*
 * Write a directory entry with parameters left as side effects
 * to a call to namei.
 */
wdir(ip)
struct inode *ip;
{

	u.u_dent.d_ino = ip->i_number;
	u.u_count = sizeof(struct direct);
	u.u_segflg = 1;
	u.u_base = (caddr_t)&u.u_dent;
	writei(u.u_pdir);
	iput(u.u_pdir);
}