ext4: Add a tracepoint for ext4_alloc_da_blocks()

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

fs/ext4/inode.c

@@ -3128,6 +3128,8 @@ static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
  */
 int ext4_alloc_da_blocks(struct inode *inode)
 {
+	trace_ext4_alloc_da_blocks(inode);
+
 	if (!EXT4_I(inode)->i_reserved_data_blocks &&
 	    !EXT4_I(inode)->i_reserved_meta_blocks)
 		return 0;

include/trace/events/ext4.h

@@ -10,6 +10,9 @@
 struct ext4_allocation_context;
 struct ext4_allocation_request;
 struct ext4_prealloc_space;
+struct ext4_inode_info;
+
+#define EXT4_I(inode) (container_of(inode, struct ext4_inode_info, vfs_inode))
 
 TRACE_EVENT(ext4_free_inode,
 	TP_PROTO(struct inode *inode),
@@ -710,6 +713,30 @@ TRACE_EVENT(ext4_sync_fs,
 		  __entry->wait)
 );
 
+TRACE_EVENT(ext4_alloc_da_blocks,
+	TP_PROTO(struct inode *inode),
+
+	TP_ARGS(inode),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__field(	ino_t,	ino			)
+		__field( unsigned int,	data_blocks	)
+		__field( unsigned int,	meta_blocks	)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= inode->i_sb->s_dev;
+		__entry->ino	= inode->i_ino;
+		__entry->data_blocks = EXT4_I(inode)->i_reserved_data_blocks;
+		__entry->meta_blocks = EXT4_I(inode)->i_reserved_meta_blocks;
+	),
+
+	TP_printk("dev %s ino %lu data_blocks %u meta_blocks %u",
+		  jbd2_dev_to_name(__entry->dev), (unsigned long) __entry->ino,
+		  __entry->data_blocks, __entry->meta_blocks)
+);
+
 #endif /* _TRACE_EXT4_H */
 
 /* This part must be outside protection */