btrfs: introduce _in_rcu variants of message printing functions

Due to the missing variants there are messages that lack the information
printed by btrfs_info etc helpers.
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -4039,14 +4039,43 @@ void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 #define btrfs_info(fs_info, fmt, args...) \
 	btrfs_printk(fs_info, KERN_INFO fmt, ##args)
 
+/*
+ * Wrappers that use printk_in_rcu
+ */
+#define btrfs_emerg_in_rcu(fs_info, fmt, args...) \
+	btrfs_printk_in_rcu(fs_info, KERN_EMERG fmt, ##args)
+#define btrfs_alert_in_rcu(fs_info, fmt, args...) \
+	btrfs_printk_in_rcu(fs_info, KERN_ALERT fmt, ##args)
+#define btrfs_crit_in_rcu(fs_info, fmt, args...) \
+	btrfs_printk_in_rcu(fs_info, KERN_CRIT fmt, ##args)
+#define btrfs_err_in_rcu(fs_info, fmt, args...) \
+	btrfs_printk_in_rcu(fs_info, KERN_ERR fmt, ##args)
+#define btrfs_warn_in_rcu(fs_info, fmt, args...) \
+	btrfs_printk_in_rcu(fs_info, KERN_WARNING fmt, ##args)
+#define btrfs_notice_in_rcu(fs_info, fmt, args...) \
+	btrfs_printk_in_rcu(fs_info, KERN_NOTICE fmt, ##args)
+#define btrfs_info_in_rcu(fs_info, fmt, args...) \
+	btrfs_printk_in_rcu(fs_info, KERN_INFO fmt, ##args)
+
 #ifdef DEBUG
 #define btrfs_debug(fs_info, fmt, args...) \
 	btrfs_printk(fs_info, KERN_DEBUG fmt, ##args)
+#define btrfs_debug_in_rcu(fs_info, fmt, args...) \
+	btrfs_printk_in_rcu(fs_info, KERN_DEBUG fmt, ##args)
 #else
 #define btrfs_debug(fs_info, fmt, args...) \
     no_printk(KERN_DEBUG fmt, ##args)
+#define btrfs_debug_in_rcu(fs_info, fmt, args...) \
+	no_printk(KERN_DEBUG fmt, ##args)
 #endif
 
+#define btrfs_printk_in_rcu(fs_info, fmt, args...)	\
+do {							\
+	rcu_read_lock();				\
+	btrfs_printk(fs_info, fmt, ##args);		\
+	rcu_read_unlock();				\
+} while (0)
+
 #ifdef CONFIG_BTRFS_ASSERT
 
 __cold