synchronous metadata update

["Shyam Burkule" <shyam.burkule@xxxxxxxxx>]

Hi, 
I am new to Linux Filesystem. I read that "Most Unix file system use synchronous writes for metadata update to ensure filesystem coverability and data intregrity after system crash." But here I am not understanding how updating metadata helps keeping fs consistent? Does it also means of keeping file data consistent? Please clarify..


Thanks 
Shyam.