ext4: check for inconsistent extents between index and leaf block

hulk inclusion
category: bugfix
bugzilla: 109205
CVE: NA
---------------------------

Now that we can check out overlapping extents in leaf block and
out-of-order index extents in index block. But the .ee_block in the
first extent of one leaf block should equal to the .ei_block in it's
parent index extent entry. This patch add a check to verify such
inconsistent between the index and leaf block.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20210908120850.4012324-3-yi.zhang@huawei.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>

conflict:
	fs/ext4/extents.c
Reviewed-by: Yang Erkun <yangerkun@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>