Fix potential infinite loop in e2fsck on really big filesystems

Prevent floating point precision errors on really big filesystems from
causing the search interpolation algorithm in the icount abstraction
from looping forever.

Addresses Debian Bug: #411838

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/lib/ext2fs/ChangeLog b/lib/ext2fs/ChangeLog
index 7d55e9d90fef3bbbbe89f9df7c0d5b6029cb4a45..b5c9add61da0cd6469df08fada74343b739807cc 100644 (file)
--- a/lib/ext2fs/ChangeLog
+++ b/lib/ext2fs/ChangeLog
@@ -1,3 +1,10 @@
+2007-04-02  Theodore Tso  <tytso@mit.edu>
+
+       * icount.c (get_icount_el): Prevent floating point precision
+               errors on really big filesystems from causing the search
+               interpolation algorithm loop forever.  (Addresses Debian
+               Bug: #411838)
+
 2007-03-21  Theodore Tso  <tytso@mit.edu>
 
        * imager.c (ext2fs_image_inode_write), inode.c

diff --git a/lib/ext2fs/icount.c b/lib/ext2fs/icount.c
index c8cdc2518e875205c10604efddc53d46e7098db9..efc74c0971d74071513010d3f63d260466ded833 100644 (file)
--- a/lib/ext2fs/icount.c
+++ b/lib/ext2fs/icount.c
@@ -247,9 +247,14 @@ static struct ext2_icount_el *get_icount_el(ext2_icount_t icount,
                                range = 0;
                        else if (ino > highval)
                                range = 1;
-                       else 
+                       else {
                                range = ((float) (ino - lowval)) /
                                        (highval - lowval);
+                               if (range > 0.9)
+                                       range = 0.9;
+                               if (range < 0.1)
+                                       range = 0.1;
+                       }
                        mid = low + ((int) (range * (high-low)));
                }
 #endif