Strangeness with Samba + quota -- pessimistic share free spaces reported

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Linux 2.0.33+ (all security patches + some performance ones) with quota 
supported compiled in
Disk mount table:
/dev/sda1       /               ext2    defaults,usrquota,grpquota 1 1
/dev/sdb2       /u2             ext2    defaults,usrquota,grpquota 1 2

Disk Free Space is as follows:
Filesystem         1024-blocks  Used Available Capacity Mounted on
/dev/sda1            3958767 2537568  1216372     68%   /
/dev/sdb2            4113072  590771  3480913     15%   /u2

Samba 1.9.18p10, compiled with -DLINUX -DSHADOW_PWD -DQUOTAS 
-DFAST_SHARE_MODES -DALLOW_CHANGE_PASSWORD
I have quota ->quota-1.51 directory just fine.

Quota support is enabled for all volumes, testparm reports no errors.  I've 
rebuilt the quota DB (checkquota) as well.
My fs superblock details (very very very short version):
Block count:              4096543
Reserved block count:     204827
Free blocks:              1421198

Disk quotas for user spamhead (uid 19000):
     Filesystem  blocks   quota   limit   grace   files   quota   limit   
grace
      /dev/sda1  636316 2048576 2068576            5907       0       0

Disk quotas for group quantgod (gid 19002):
     Filesystem  blocks   quota   limit   grace   files   quota   limit   
grace
      /dev/sda1 1827498 3000000 3100000           36601       0       0

I have 4 shares....  home, a Public (read+write a group spamhead's a part 
of), Applications (read only same group, write special-group), and webroot 
(read-write only special group, which spamhead's a part of, which does a 
force user and group to my web server's owner).

>From WindowsNT4SP3 shares, I see the following disk space free (in the "root" 
browser window of the Active Crashtop Explorer:

Name             Total Size       Free Space
Applications:      1.95GB           593MB
Public:            1.95GB           593MB
spamhead:          1.95GB           593MB
Webroot:           3.74GB          1.15GB

So... The Total Size of the shares looks like - it makes sense to "clip" the 
values to my soft quota limit.  That's reasonable.  However, why is the free 
space off by 560MB?  Note that Webroot (which has an unlimited quota (the web 
account it's force user'ed to)) displays the correct free space.

My Macintosh clients which use Netatalk display correct free space on the 
same shares (1.15GB)...  So where is samba coming up with these free space 
values?  My quota system is working correctly, I repquota everyone and 
everything's accurate.  I take into account the free space on the devices in 
question, and things look correct.  (I have a larger quota than free space on 
the devices, so I imagine samba would just return the free space of the 
volumes to the clients, no?)

Anyway, what's the matter here?  Since it's over-pessimistic, I suppose from 
a data-loss standpoint, I'm not in any risk of doing something bad.  It's 
just annoying.

Any thoughts?

=Robert=