replace genext2fs with populate-extfs.sh

* The benefits:
- Really support ext4
- Support the sparse file (the sparse file became into the common file before)
- Have a uniform code for ext2/3/4 generation
- Remove the depends on genext2fs-native

* Impact
- Build time:
a) If we build fresh core-image-sato, there is nearly no impact.
b) If we do the image generation, which means:
$ bitbake core-image-sato
$ bitbake core-image-sato -ccleansstate
$ bitbake core-image-sato
About 50 extra seconds are needed, here is my test result:
Before the patches: 4m25s
After the patches: 5m17s
This is because the genext2fs is much faster than the populate-extfs.sh, we will replace this script by the mke2fs when it supports create the filesystem from a initial directory.

- Disk space (take core-image-sato as an example)

    a) The image file size is the same as before (529M)
    b) The disk usage is a little different: (du -sh)
              before       now 
       ext2:  364M         388M
       ext3:  381M         404M
       ext4:  380M         387M

We may need to adjust the IMAGE_OVERHEAD_FACTOR from 1.3 to 1.4.

I have done some simple runtime testing on core-image-sato and core-image-minimal, they worked well.

// Robert

The following changes since commit 3472c1f7ab409cd91c1d4782d9e00880b84e3ae8:

grub-efi-native: Cleanup whitespace (2013-05-03 16:37:05 +0100)

are available in the git repository at:

git://git.pokylinux.org/poky-contrib robert/ext4
http://git.pokylinux.org/cgit.cgi/poky-contrib/log/?h=robert/ext4

Robert Yang (4):
e2fsprogs: the max length of debugfs argument is too short
e2fsprogs: let debugfs do sparse copy
e2fsprogs: add populate-extfs.sh image_types.bbclass: replace genext2fs with populate-extfs.sh

 meta/classes/image_types.bbclass                   |   46 ++++----
 .../e2fsprogs-1.42.7/debugfs-too-short.patch       |   28 +++++
 .../e2fsprogs/e2fsprogs-1.42.7/populate-extfs.sh   |   93 ++++++++++++++++
 .../e2fsprogs/e2fsprogs-1.42.7/sparse_copy.patch   |  114 ++++++++++++++++++++
 .../recipes-devtools/e2fsprogs/e2fsprogs_1.42.7.bb |    4 +
 5 files changed, 257 insertions(+), 28 deletions(-)
 create mode 100644 meta/recipes-devtools/e2fsprogs/e2fsprogs-1.42.7/debugfs-too-short.patch
 create mode 100644 meta/recipes-devtools/e2fsprogs/e2fsprogs-1.42.7/populate-extfs.sh
 create mode 100644 meta/recipes-devtools/e2fsprogs/e2fsprogs-1.42.7/sparse_copy.patch

1.7.10.4