question: are the metadata crc elements ready for general use?

[Joe Landman]

I ask as I see this in the 3.2.2 mkfs.xfs command.  The default is to 
leave them off from what I can see on an mkfs.xfs.

root at unison:~/xfsprogs# mkfs.xfs /dev/sda
meta-data=/dev/sda               isize=256    agcount=55, 
agsize=268435455 blks
          =                       sectsz=512   attr=2, projid32bit=1
          =                       crc=0        finobt=0
data     =                       bsize=4096   blocks=14627632640, imaxpct=1
          =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=0
log      =internal log           bsize=4096   blocks=521728, version=2
          =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

But they are there, and I am curious as to the developers/users 
thoughts.  Will they break things (nfs, CIFS/samba)?

Thanks!

Joe