Hello there.
I'm using Ubuntu 10.10 on ext4 file system and have exported a directory "/home/dbs/exp1/" through Samba on Windows(on VirtualBox).
I need to modify the acls for the files in the above directory both from Ubuntu and Windows.
For linux, I'm using setfacl utility to modify ACLs, but it says that "Operation is not supported". From google I got to know that acl and user_xattr support has to be enabled at the mount point to modify the ACLs
So, can anyone tell me clearly, what should I do to enable ACL support?

I tried:
sudo mount /home/dbs/exp1 -o remount,acl

but it says:
mount: can't find /home/dbs/exp1 in /etc/fstab or /etc/mtab

My /etc/fstab looks like:

# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc nodev,noexec,nosuid 0 0
# / was on /dev/sda5 during installation

UUID=66eeee3e-b860-41b0-abf7-074c0e08420e / ext4 errors=remount-ro 0 1

#Entry for /dev/sda2 :
UUID=2080E92980E905DE /media/Data ntfs defaults,uid=dbs,gid=dbs,umask=000,windows_names 0 0

#Entry for /dev/sda1 :
/dev/sda1 /media/Windows_XP ntfs defaults,uid=dbs2,gid=dbs2,umask=000,windows_names 0 0


Please help me!
Thanks in advance.

You need to remount the mount point -- in this specific case, the root / filesystem, not just the desired directory. In other words, try
For future, change the line in /etc/fstab to
and POSIX ACL's will be enabled for you even after a reboot.

(The relatime option relaxes file access time (atime) updates; it reduces writes to disks when you are just reading from it.)

1 members found this post helpful.

Bingo!!
Thank you thank you Nomial Animal.
It's working now.
Thanks a ton!