1) intent of the patch is to get possibility to store EAs in the body of large
   inode. it saves space and improves performance in some cases

2) the patch is quite simple: it works the same way original xattr does, but
   using other storage (inode body). body has priority over separate block.
   original routines (ext3_xattr_get, ext3_xattr_list, ext3_xattr_set) are
   renamed to ext3_xattr_block_*. new routines that handle inode storate are
   added (ext3_xattr_ibody_get, ext3_xattr_ibody_list, ext3_xattr_ibody_set).
   routines ext3_xattr_get, ext3_xattr_list and ext3_xattr_set allow user to
   accesss both the storages transparently

3) the change makes sense on filesystem with inode size >= 256 bytes only.
   2.4 kernels don't support such a filesystems, AFAIK. 2.6 kernels do support
   and ignore EAs stored in a body w/o the patch

4) debugfs and e2fsck need to be patched to deal with EAs in inode
   the patch will be sent later

5) testing results:
	a) Andrew Samba Master (tridge) has done successful tests
	b) we've been using ea-in-inode feature in Lustre for many months
Signed-off-by: Andreas Dilger <adilger@clusterfs.com>
Signed-off-by: Alex Tomas <alex@clusterfs.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>