better estimate for files with holes using "di_blocks"

SCCS-vsn: sbin/dump/itime.c 1.13

diff --git a/usr/src/sbin/dump/itime.c b/usr/src/sbin/dump/itime.c
index 8ea2b37..e3fa877 100644 (file)
--- a/usr/src/sbin/dump/itime.c
+++ b/usr/src/sbin/dump/itime.c
@@ -1,4 +1,4 @@
-static char *sccsid = "@(#)itime.c     1.12 (Berkeley) %G%";
+static char *sccsid = "@(#)itime.c     1.13 (Berkeley) %G%";

 
 #include "dump.h"
 #include <sys/file.h>
 
 #include "dump.h"
 #include <sys/file.h>


@@ -204,20 +204,37 @@ int makeidate(ip, buf)
 
 /*
  * This is an estimation of the number of TP_BSIZE blocks in the file.
 
 /*
  * This is an estimation of the number of TP_BSIZE blocks in the file.

- * It assumes that there are no unallocated blocks; hence
- * the estimate may be high
+ * It estimates the number of blocks in files with holes by assuming
+ * that all of the blocks accounted for by di_blocks are data blocks
+ * (when some of the blocks are usually used for indirect pointers);
+ * hence the estimate may be high.

  */
 est(ip)
        struct dinode *ip;
 {
  */
 est(ip)
        struct dinode *ip;
 {

-       long s;
+       long s, t;

 
 

+       /*
+        * ip->di_size is the size of the file in bytes.
+        * ip->di_blocks stores the number of sectors actually in the file.
+        * If there are more sectors than the size would indicate, this just
+        *      means that there are indirect blocks in the file or unused
+        *      sectors in the last file block; we can safely ignore these
+        *      (s = t below).
+        * If the file is bigger than the number of sectors would indicate,
+        *      then the file has holes in it.  In this case we must use the
+        *      block count to estimate the number of data blocks used, but
+        *      we use the actual size for estimating the number of indirect
+        *      dump blocks (t vs. s in the indirect block calculation).
+        */

        esize++;
        esize++;

-       /* calc number of TP_BSIZE blocks */
-       s = howmany(ip->di_size, TP_BSIZE);
+       s = howmany(dbtob(ip->di_blocks), TP_BSIZE);
+       t = howmany(ip->di_size, TP_BSIZE);
+       if ( s > t )
+               s = t;

        if (ip->di_size > sblock->fs_bsize * NDADDR) {
        if (ip->di_size > sblock->fs_bsize * NDADDR) {

-               /* calc number of indirect blocks on the dump tape */
-               s += howmany(s - NDADDR * sblock->fs_bsize / TP_BSIZE,
+               /* calculate the number of indirect blocks on the dump tape */
+               s += howmany(t - NDADDR * sblock->fs_bsize / TP_BSIZE,

                        TP_NINDIR);
        }
        esize += s;
                        TP_NINDIR);
        }
        esize += s;