f2fs: add tracepoints to debug the block allocation

Add tracepoints to debug the block allocation & fallocate.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Pankaj Kumar <pankaj.km@samsung.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
[Jaegeuk: enhance information]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 71efa37..0e56db2 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -546,6 +546,7 @@
 		inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 		mark_inode_dirty(inode);
 	}
+	trace_f2fs_fallocate(inode, mode, offset, len, ret);
 	return ret;
 }