ocfs2: add missing annotations for ocfs2_refcount_cache_lock() and ocfs2_refcount_cache_unlock()

Sparse reports warnings at ocfs2_refcount_cache_lock()
	and ocfs2_refcount_cache_unlock()

warning: context imbalance in ocfs2_refcount_cache_lock()
	- wrong count at exit
warning: context imbalance in ocfs2_refcount_cache_unlock()
	- unexpected unlock

The root cause is the missing annotation at ocfs2_refcount_cache_lock()
and at ocfs2_refcount_cache_unlock()

Add the missing __acquires(&rf->rf_lock) annotation to
ocfs2_refcount_cache_lock()

Add the missing __releases(&rf->rf_lock) annotation to
ocfs2_refcount_cache_unlock()
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-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>
Link: http://lkml.kernel.org/r/20200224204130.18178-1-jbi.octave@gmail.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/refcounttree.c

@@ -154,6 +154,7 @@ ocfs2_refcount_cache_get_super(struct ocfs2_caching_info *ci)
 }
 
 static void ocfs2_refcount_cache_lock(struct ocfs2_caching_info *ci)
+__acquires(&rf->rf_lock)
 {
 	struct ocfs2_refcount_tree *rf = cache_info_to_refcount(ci);
 
@@ -161,6 +162,7 @@ static void ocfs2_refcount_cache_lock(struct ocfs2_caching_info *ci)
 }
 
 static void ocfs2_refcount_cache_unlock(struct ocfs2_caching_info *ci)
+__releases(&rf->rf_lock)
 {
 	struct ocfs2_refcount_tree *rf = cache_info_to_refcount(ci);