ext4: fix wrong return err in ext4_load_and_init_journal()

The return value is wrong in ext4_load_and_init_journal(). The local
variable 'err' need to be initialized before goto out. The original code
in __ext4_fill_super() is fine because it has two return values 'ret'
and 'err' and 'ret' is initialized as -EINVAL. After we factor out
ext4_load_and_init_journal(), this code is broken. So fix it by directly
returning -EINVAL in the error handler path.

Cc: stable@kernel.org
Fixes: 9c1dd22d ("ext4: factor out ext4_load_and_init_journal()")
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221025040206.3134773-1-yanaijie@huawei.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/super.c

@@ -4886,7 +4886,7 @@ static int ext4_load_and_init_journal(struct super_block *sb,
 	flush_work(&sbi->s_error_work);
 	jbd2_journal_destroy(sbi->s_journal);
 	sbi->s_journal = NULL;
-	return err;
+	return -EINVAL;
 }
 
 static int ext4_journal_data_mode_check(struct super_block *sb)