ext4: fix e2fsprogs checksum failure for mounted filesystem

mainline inclusion
from mainline-v5.15
commit b2bbb92f
category: bugfix
bugzilla: 179956 https://gitee.com/openeuler/kernel/issues/I4DDEL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b2bbb92f7042e8075fb036bf97043339576330c3



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Commit 81414b4d ("ext4: remove redundant sb checksum
recomputation") removed checksum recalculation after updating
superblock free space / inode counters in ext4_fill_super() based on
the fact that we will recalculate the checksum on superblock
writeout.

That is correct assumption but until the writeout happens (which can
take a long time) the checksum is incorrect in the buffer cache and if
programs such as tune2fs or resize2fs is called shortly after a file
system is mounted can fail.  So return back the checksum recalculation
and add a comment explaining why.

Fixes: 81414b4d ("ext4: remove redundant sb checksum recomputation")
Cc: stable@kernel.org
Reported-by: Boyang Xue <bxue@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20210812124737.21981-1-jack@suse.cz


Signed-off-by: Zheng Liang <zhengliang6@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>