ext4: add tracepoints for shutdown and file system errors

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/ioctl.c

@@ -481,6 +481,7 @@ static int ext4_shutdown(struct super_block *sb, unsigned long arg)
 		return 0;
 
 	ext4_msg(sb, KERN_ALERT, "shut down requested (%d)", flags);
+	trace_ext4_shutdown(sb, flags);
 
 	switch (flags) {
 	case EXT4_GOING_FLAGS_DEFAULT:

fs/ext4/super.c

@@ -448,6 +448,7 @@ void __ext4_error(struct super_block *sb, const char *function,
 	if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
 		return;
 
+	trace_ext4_error(sb, function, line);
 	if (ext4_error_ratelimit(sb)) {
 		va_start(args, fmt);
 		vaf.fmt = fmt;
@@ -472,6 +473,7 @@ void __ext4_error_inode(struct inode *inode, const char *function,
 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 		return;
 
+	trace_ext4_error(inode->i_sb, function, line);
 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
 	es->s_last_error_block = cpu_to_le64(block);
 	if (ext4_error_ratelimit(inode->i_sb)) {
@@ -507,6 +509,7 @@ void __ext4_error_file(struct file *file, const char *function,
 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 		return;
 
+	trace_ext4_error(inode->i_sb, function, line);
 	es = EXT4_SB(inode->i_sb)->s_es;
 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
 	if (ext4_error_ratelimit(inode->i_sb)) {
@@ -719,6 +722,7 @@ __acquires(bitlock)
 	if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
 		return;
 
+	trace_ext4_error(sb, function, line);
 	es->s_last_error_ino = cpu_to_le32(ino);
 	es->s_last_error_block = cpu_to_le64(block);
 	__save_error_info(sb, function, line);

include/trace/events/ext4.h

@@ -2585,6 +2585,49 @@ DEFINE_GETFSMAP_EVENT(ext4_getfsmap_low_key);
 DEFINE_GETFSMAP_EVENT(ext4_getfsmap_high_key);
 DEFINE_GETFSMAP_EVENT(ext4_getfsmap_mapping);
 
+TRACE_EVENT(ext4_shutdown,
+	TP_PROTO(struct super_block *sb, unsigned long flags),
+
+	TP_ARGS(sb, flags),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__field(     unsigned,	flags			)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= sb->s_dev;
+		__entry->flags	= flags;
+	),
+
+	TP_printk("dev %d,%d flags %u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->flags)
+);
+
+TRACE_EVENT(ext4_error,
+	TP_PROTO(struct super_block *sb, const char *function,
+		 unsigned int line),
+
+	TP_ARGS(sb, function, line),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__field( const char *,	function		)
+		__field(     unsigned,	line			)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= sb->s_dev;
+		__entry->function = function;
+		__entry->line	= line;
+	),
+
+	TP_printk("dev %d,%d function %s line %u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->function, __entry->line)
+);
+
 #endif /* _TRACE_EXT4_H */
 
 /* This part must be outside protection */