CentOS - Sep 2010 - how to show that a filesystem is ACL-enabled?

currently reading the RHEL deployment guide and i have a short
question about ACLs that i can test on my centos 5.5 box.

  here:

http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Deployment_Guide/ch-acls.html

the manual clearly claims that, in order to use ACLs on a filesystem,
that filesystem must be mounted with the "acl" mount option, and even
shows a sample /etc/fstab entry that represents that.

  however, i just verified that i can use setfacl to give my non-root
account read access to /etc/shadow so, clearly(?), the root filesystem
supports ACLs, but the mount entry for that filesystem in /etc/fstab
reads only "defaults" and, as i read it in the man page for
"mount",
the "defaults" option is not listed as including the "acl"
option.

  can someone clarify this?  is there a command that shows whether a
filesystem is currently acl-enabled?  and is the mount man page
simply incomplete in that respect?  thanks.

rday

-- 

=======================================================================Robert P.
J. Day                               Waterloo, Ontario, CANADA

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>   
>    can someone clarify this?  is there a command that shows whether a
> filesystem is currently acl-enabled?  and is the mount man page
> simply incomplete in that respect?  thanks.
tune2fs -l /dev/[hda1,sda1]

The values between [ ] are an example only. Replace, of course, with 
your own storage device.

Look at "Filesystem features" and "Default mount options".