386BSD 0.1 development

Work on file usr/src/sys.386bsd/i386/stand/bmap.c

Co-Authored-By: Lynne Greer Jolitz <ljolitz@cardio.ucsf.edu>
Synthesized-from: 386BSD-0.1

diff --git a/usr/src/sys.386bsd/i386/stand/bmap.c b/usr/src/sys.386bsd/i386/stand/bmap.c
new file mode 100644 (file)
index 0000000..fb50984
--- /dev/null
+++ b/usr/src/sys.386bsd/i386/stand/bmap.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 1982, 1986, 1989 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the University of
+ *     California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *     derived from: @(#)ufs_bmap.c    7.13 (Berkeley) 5/8/91
+ */
+
+#include "param.h"
+#include "dinode.h"
+#include "fs.h"
+#include "errno.h"
+
+/*
+ * Bmap converts a the logical block number of a file
+ * to its physical block number on the disk. The conversion
+ * is done by using the logical block number to index into
+ * the array of block pointers described by the dinode.
+ */
+extern struct fs *fs;
+extern int bdev;
+
+static daddr_t bap[2*1024];
+static daddr_t bnobap;
+
+bmap(dip, bn, bnp)
+       register struct dinode *dip;
+       register daddr_t bn;
+       daddr_t *bnp;
+{
+       register daddr_t nb;
+       int i, j, sh;
+       int error;
+
+/*fprintf(stderr, "bmap %d ", bn);*/
+       if (bn < 0)
+               return (EFBIG);
+
+       /*
+        * The first NDADDR blocks are direct blocks
+        */
+       if (bn < NDADDR) {
+               nb = dip->di_db[bn];
+               if (nb == 0) {
+                       *bnp = (daddr_t)-1;
+/*fprintf(stderr, "%d\n", *bnp);*/
+                       return (0);
+               }
+               *bnp = fsbtodb(fs, nb);
+/*fprintf(stderr, "%d\n", *bnp);*/
+               return (0);
+       }
+       /*
+        * Determine the number of levels of indirection.
+        */
+       sh = 1;
+       bn -= NDADDR;
+       for (j = NIADDR; j > 0; j--) {
+               sh *= NINDIR(fs);
+               if (bn < sh)
+                       break;
+               bn -= sh;
+       }
+       if (j == 0)
+               return (EFBIG);
+       /*
+        * Fetch through the indirect blocks.
+        */
+       nb = dip->di_ib[NIADDR - j];
+       if (nb == 0) {
+               *bnp = (daddr_t)-1;
+/*fprintf(stderr, "%d\n", *bnp);*/
+               return (0);
+       }
+       for (; j <= NIADDR; j++) {
+               daddr_t bno = fsbtodb(fs, nb);
+
+               if (bnobap != bno &&
+(error = bread(bdev, bno, &bap,
+                       (int)fs->fs_bsize))) {
+                       return (error);
+               }
+               bnobap = bno;
+               sh /= NINDIR(fs);
+               i = (bn / sh) % NINDIR(fs);
+               nb = bap[i];
+               if (nb == 0) {
+                       *bnp = (daddr_t)-1;
+/*fprintf(stderr, "%d\n", *bnp);*/
+                       return (0);
+               }
+       }
+       *bnp = fsbtodb(fs, nb);
+/*fprintf(stderr, "%d\n", *bnp);*/
+       return (0);
+}