Revert the bitmap randomization change, which had the side effect of

causing enough disk fragmentation for the base (extent-based) file
system that in some cases tests would fail.  Also, it confused the
hell out of everyone.  Failed experiment.

diff --git a/src/lib/kernel/bitmap.c b/src/lib/kernel/bitmap.c
index 77edf2270b35435538fbbb5adeec52096403f50b..d323b8982e552c1dcc7ab385de78786b661aa36a 100644 (file)
--- a/src/lib/kernel/bitmap.c
+++ b/src/lib/kernel/bitmap.c
@@ -1,7 +1,6 @@
 #include "bitmap.h"
 #include <debug.h>
 #include <limits.h>
-#include <random.h>
 #include <round.h>
 #include <stdio.h>
 #include "threads/malloc.h"
@@ -290,7 +289,7 @@ bitmap_all (const struct bitmap *b, size_t start, size_t cnt)
 \f
 /* Finding set or unset bits. */
 
-/* Finds and returns the starting index of a group of CNT
+/* Finds and returns the starting index of the first group of CNT
    consecutive bits in B at or after START that are all set to
    VALUE.
    If there is no such group, returns BITMAP_ERROR. */
@@ -303,20 +302,15 @@ bitmap_scan (const struct bitmap *b, size_t start, size_t cnt, bool value)
   if (cnt <= b->bit_cnt) 
     {
       size_t last = b->bit_cnt - cnt;
-      size_t middle = start + random_ulong () % (last - start + 1); 
-      size_t i = middle;
-      do
-        {
-          if (!bitmap_contains (b, i, cnt, !value))
-            return i; 
-          i = i != last ? i + 1 : start;
-        }
-      while (i != middle);
+      size_t i;
+      for (i = start; i <= last; i++)
+        if (!bitmap_contains (b, i, cnt, !value))
+          return i; 
     }
   return BITMAP_ERROR;
 }
 
-/* Finds a group of CNT consecutive bits in B at or after
+/* Finds the first group of CNT consecutive bits in B at or after
    START that are all set to VALUE, flips them all to !VALUE,
    and returns the index of the first bit in the group.
    If there is no such group, returns BITMAP_ERROR.