ADSM-L

[ADSM-L] Upgrade of Linux Client 5.3->5.4 and filesystem ACLs

2008-02-05 06:50:07
Subject: [ADSM-L] Upgrade of Linux Client 5.3->5.4 and filesystem ACLs
From: Rainer Schöpf <rainer.schoepf AT PROTEOSYS DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Tue, 5 Feb 2008 12:49:26 +0100
Hello TSMers!

After upgrading the TSM Linux client on one of our fileservers (x68_64) 
from 5.3.5 to 5.4.1, the next incremental started to backup all files 
again. I traced this to a change in the handling of filesystem ACLs by the 
TSM client.

The filesystem in question is xfs.

For the time being, I went back to 5.3.5 (server is 5.4.1.0 on W2K3). I 
can live with that for a while.

I traced the problem with strace and client -TRACEFLags=service. This 
shows that the 5.4 does not use the libacl interface, but accesses the 
extended attributes directly with the getxattr system call. And indeed, 
the TSM client trace shows this:

04.02.2008 12:48:39.468 : unxfilio.cpp        (1571): fioCmpAttribs: Attribute 
comparison of two directories
Attribute               Old                     New
---------               ---                     ---
File mode            16893                   16893
uid                    501                     501
gid                    100                     100
ACL size               424                       0
ACL checksum    3721320641                       0
Xattr size               0                     494
Xattr checksum           0              3013615671
04.02.2008 12:48:39.468 : fileio.cpp          (4627): fioCmpAttribs(): old 
attrib's data from build (IBM TSM 5.4.1.2)
04.02.2008 12:48:39.468 : unxfilio.cpp        (1825): -->Attribs different: 
returning ATTRIBS_BACKUP

It is interesting that in Technote swg21249081 libacl is mentioned as a 
potential problem to look for, but not getxattr. I made sure that libacl 
is present, but the strace output shows that it isn't used.

This is very annoying. It means that the TSM client will probably force a 
backup of every file with an ACL when I upgrade from 5.3 to 5.4.

Is this change documented somewhere? Is there a way to go back to either 
using libacl with the 5.4 client, or get the same ACL size/checksum from 
the Attributes comparison?
 
 Rainer Schöpf

--------------------------------------------------------
ProteoSys AG
Carl-Zeiss-Straße 51
55129 Mainz

Dr. Rainer Schöpf
Leiter Software/Softwareentwicklung

Mail:   rainer.schoepf AT proteosys DOT com
Phone:  +49-(0)6131-50192-41
Fax:    +49-(0)6131-50192-11
WWW:    http://www.proteosys.com/
--------------------------------------------------------
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Amtsgericht Mainz HRB 7508 - USt.-Id Nr.: DE213940570
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Vorsitzender des Aufsichtsrates: Dr. Werner Zöllner

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