ext4: avoid allocating blocks from corrupted group in ext4_mb_find_by_goal()

Places the logic for checking if the group's block bitmap is corrupt under
the protection of the group lock to avoid allocating blocks from the group
with a corrupted block bitmap.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20240104142040.2835097-8-libaokun1@huawei.com


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