ext4: warn if delalloc counters are not zero on inactive

ext4: warn if delalloc counters are not zero on inactive

The per-inode i_reserved_data_blocks count the reserved delalloc blocks
in a regular file, it should be zero when destroying the file. The
per-fs s_dirtyclusters_counter count all reserved delalloc blocks in a
filesystem, it also should be zero when umounting the filesystem. Now we
have only an error message if the i_reserved_data_blocks is not zero,
which is unable to be simply captured, so add WARN_ON_ONCE to make it
more visable.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20240517124005.347221-4-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>