chattr: Add extent conversion support

This patch adds new option, +e to chattr. The +e option
is used to convert the ext3 format (non extent) file
to ext4 (extent) format. This can be used to migrate
the ext3 file system to ext4 file system.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/misc/chattr.1.in b/misc/chattr.1.in
index d1c4cb5..e1e6a85 100644
--- a/misc/chattr.1.in
+++ b/misc/chattr.1.in
@@ -19,7 +19,7 @@
 .B chattr
 changes the file attributes on a Linux second extended file system.
 .PP
-The format of a symbolic mode is +-=[ASacDdIijsTtu].
+The format of a symbolic mode is +-=[ASacDdeIijsTtu].
 .PP
 The operator `+' causes the selected attributes to be added to the
 existing attributes of the files; `-' causes them to be removed; and
@@ -74,10 +74,8 @@
 .BR lsattr (1).
 .PP
 The 'e' attribute indicates that the file is using extents for mapping
-the blocks on disk.  It may not be set or reset using
-.BR chattr (1),
-although it can be displayed by
-.BR lsattr (1).
+the blocks on disk.  It may not be removed using
+.BR chattr (1).
 .PP
 The 'I' attribute is used by the htree code to indicate that a directory
 is being indexed using hashed trees.  It may not be set or reset using