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 (file)
index 0000000..424797b
--- /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);
+}