commit c7c539e8fd86de691475eea00409c6c030f312cd
Author: Darrick J. Wong <darrick.wong@oracle.com>
Date:   Tue Jul 22 12:40:56 2014 -0400

    e4defrag: backwards-allocated files should be defragmented too
    
    Currently, e4defrag avoids increasing file fragmentation by comparing
    the number of runs of physical extents of both the original and the
    donor files.  Unfortunately, there is a bug in the routine that counts
    physical extents, since it doesn't look at the logical block offsets
    of the extents.  Therefore, a file whose blocks were allocated in
    reverse order will be seen as only having one big physical extent, and
    therefore will not be defragmented.
    
    Fix the counting routine to consider logical extent offset so that we
    defragment backwards-allocated files.  This could be problematic if we
    ever gain the ability to lay out logically sparse extents in a
    physically contiguous manner, but presumably one wouldn't call defrag
    on such a file.
    
    Reported-by: Xiaoguang Wang <wangxg.fnst@cn.fujitsu.com>
    Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
    Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Index: e2fsprogs-1.42.9/misc/e4defrag.c
===================================================================
--- e2fsprogs-1.42.9.orig/misc/e4defrag.c
+++ e2fsprogs-1.42.9/misc/e4defrag.c
@@ -941,7 +941,9 @@ static int get_physical_count(struct fie
 
 	do {
 		if ((ext_list_tmp->data.physical + ext_list_tmp->data.len)
-				!= ext_list_tmp->next->data.physical) {
+				!= ext_list_tmp->next->data.physical ||
+		    (ext_list_tmp->data.logical + ext_list_tmp->data.len)
+				!= ext_list_tmp->next->data.logical) {
 			/* This extent and next extent are not continuous. */
 			ret++;
 		}