jbd2: Make credit checking more strict

mainline inclusion
from mainline-5.5-rc1
commit d090707e
category: bugfix
bugzilla: 25031
CVE: NA
---------------------------

Make checking of available credits in jbd2_journal_dirty_metadata() more
strict. There should be always enough credits in the handle to write all
potential revoke descriptors. Also we warn in case there are not enough
credits since this is a bug in the filesystem.

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20191105164437.32602-22-jack@suse.cz


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

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Reviewed-by: Yang Erkun <yangerkun@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>