ext4: add operations on extent status tree

This patch adds operations on a extent status tree.

CC: Lukas Czerner <[email protected]>
Signed-off-by: Yongqiang Yang <[email protected]>
Signed-off-by: Allison Henderson <[email protected]>
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Zheng Liu <[email protected]>
Signed-off-by: "Theodore Ts'o" <[email protected]>
3 files changed