From: Keith Bostic <bostic@ucbvax.Berkeley.EDU>
Date: Mon, 6 May 1991 04:19:54 +0000 (-0800)
Subject: date and time created 91/05/05 13:19:54 by bostic
X-Git-Tag: BSD-4_4-Snapshot-Development~10958
X-Git-Url: https://git.subgeniuskitty.com/unix-history/.git/commitdiff_plain/40380a726a831affefb99f1fb303ca59a1358865?ds=inline

date and time created 91/05/05 13:19:54 by bostic

SCCS-vsn: sys/stand.att/bmap.c 7.1
---

diff --git a/usr/src/sys/stand.att/bmap.c b/usr/src/sys/stand.att/bmap.c
new file mode 100644
index 0000000000..424797b5bb
--- /dev/null
+++ b/usr/src/sys/stand.att/bmap.c
@@ -0,0 +1,83 @@
+/*-
+ * Copyright (c) 1982, 1988 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * %sccs.include.proprietary.c%
+ *
+ *	@(#)bmap.c	7.1 (Berkeley) %G%
+ */
+
+#include <sys/param.h>
+#include "saio.h"
+
+#define	NBUFS	4
+static char	b[NBUFS][MAXBSIZE];
+static daddr_t	blknos[NBUFS];
+
+daddr_t
+bmap(io, bn)
+	register struct iob *io;
+	daddr_t bn;
+{
+	register struct dinode *ip;
+	int i, j, sh;
+	daddr_t nb, *bap;
+
+	ip = &io->i_ino;
+	if (bn < 0) {
+		printf("bn negative\n");
+		return ((daddr_t)0);
+	}
+
+	/* The first NDADDR blocks are direct blocks. */
+	if(bn < NDADDR) {
+		nb = ip->di_db[bn];
+		return (nb);
+	}
+
+	/* Determine the number of levels of indirection. */
+	sh = 1;
+	bn -= NDADDR;
+	for (j = NIADDR; j > 0; j--) {
+		sh *= NINDIR(&io->i_fs);
+		if (bn < sh)
+			break;
+		bn -= sh;
+	}
+	if (j == 0) {
+		printf("bn ovf %D\n", bn);
+		return ((daddr_t)0);
+	}
+
+	/* Get the first indirect block address. */
+	nb = ip->di_ib[NIADDR - j];
+	if (nb == 0) {
+		printf("bn void %D\n",bn);
+		return ((daddr_t)0);
+	}
+
+	/* Get the indirect blocks. */
+	for (; j <= NIADDR; j++) {
+		if (blknos[j] != nb) {
+			io->i_bn = fsbtodb(&io->i_fs, nb) + io->i_boff;
+			io->i_ma = b[j];
+			io->i_cc = io->i_fs.fs_bsize;
+			if (devread(io) != io->i_fs.fs_bsize) {
+				if (io->i_error)
+					errno = io->i_error;
+				printf("bn %D: read error\n", io->i_bn);
+				return ((daddr_t)0);
+			}
+			blknos[j] = nb;
+		}
+		bap = (daddr_t *)b[j];
+		sh /= NINDIR(&io->i_fs);
+		i = (bn / sh) % NINDIR(&io->i_fs);
+		nb = bap[i];
+		if(nb == 0) {
+			printf("bn void %D\n",bn);
+			return ((daddr_t)0);
+		}
+	}
+	return (nb);
+}