jbd2: export jbd2_journal_[grab|put]_journal_head

Patch series "ocfs2: fix a deadlock case".

This fixes a deadlock case in ocfs2.  We firstly export jbd2 symbols
jbd2_journal_[grab|put]_journal_head as preparation and later use them
in ocfs2 insread of jbd_[lock|unlock]_bh_journal_head to fix the
deadlock.

This patch (of 2):

This exports symbols jbd2_journal_[grab|put]_journal_head, which will be
used outside modules, e.g.  ocfs2.

Link: https://lkml.kernel.org/r/20220121071205.100648-2-joseph.qi@linux.alibaba.com


Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Gautham Ananthakrishna <gautham.ananthakrishna@oracle.com>
Cc: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>