jbd2: track more dependencies on transaction commit

So far we were tracking only dependency on transaction commit due to
starting a new handle (which may require commit to start a new
transaction). Now add tracking also for other cases where we wait for
transaction commit. This way lockdep can catch deadlocks e. g. because we
call jbd2_journal_stop() for a synchronous handle with some locks held
which rank below transaction start.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

include/linux/jbd2.h

@@ -1046,6 +1046,12 @@ struct journal_s
 #endif
 };
 
+#define jbd2_might_wait_for_commit(j) \
+	do { \
+		rwsem_acquire(&j->j_trans_commit_map, 0, 0, _THIS_IP_); \
+		rwsem_release(&j->j_trans_commit_map, 1, _THIS_IP_); \
+	} while (0)
+
 /* journal feature predicate functions */
 #define JBD2_FEATURE_COMPAT_FUNCS(name, flagname) \
 static inline bool jbd2_has_feature_##name(journal_t *j) \