RHBA-2013:0530 - Bug Fix Advisory

Topic

Updated sanlock packages that fix several bugs and add various enhancements are
now available for Red Hat Enterprise Linux 6.

Description

The sanlock packages provide a shared storage lock manager. Hosts with shared
access to a block device or file can use sanlock to synchronize their
activities. VDSM and libvirt use sanlock to synchronize access to virtual
machine images.

The sanlock packages have been upgraded to upstream version 2.6, which provides
a number of bug fixes and enhancements over the previous version, including the
new io_timeout setting, which has been added to the lockspace API. I/O timeouts
can now be adjusted directly with sanlock. (BZ#843073)

This update fixes the following bugs:

• In certain cases, an internal sanlock race condition occurred between the

add_lockspace and rem_lockspace API. This made add_lockspace difficult to use
from applications where multiple threads could be adding the same lockspace.
With this update, it is possible for the threads to coordinate the lockspace
operations. As a result, the aforementioned error no longer occurs. (BZ#830736)

• Prior to this update, the sanlock init script was not creating the

/var/lock/subsys/sanlock file. Consequently, the killall init script, which uses
such files to stop init services, did not terminate the sanlock service. This
bug has been fixed, and the /var/lock/subsys/sanlock file is now properly
created. (BZ#830848)

• Previously, the sanlock service ignored undefined UID and GID options, which

led to a segmentation fault during the service startup. This bug has been fixed,
and the segmentation fault no longer occurs. (BZ#831906)

• Previously, the wdmd init script did not start the softdog module when no

watchdog device was loaded. Consequently, the wdmd and sanlock daemons failed to
start. The bug has been fixed, and softdog is now correctly loaded in the
described scenario. (BZ#832935)

• The sanlock inquire API was returning a lease version (lver) of "0" instead of

the real lver in the state string. Consequently, procedures like migrate,
suspend or resume failed to acquire a lease with an inquired version. The bug
has been fixed, and the correct lver number is now returned by sanlock inquire.
(BZ#840063)

• Prior to this update, the sanlock daemon acquired supplementary groups to

allow file access on NFS. Some NFS servers did not recognize these groups and
refused the file access. With this update, the sanlock daemon has been modified
to and the aformentioned problem no longer occurs. (BZ#841305)

This update also adds the following enhancements:

• With this update, when the storage domain (lockspace) is unreachable, the

sanlock manager suspends affected processes instead of killing them. When the
host regains access to lockspace, these processes are resumed. (BZ#826022)

• With this update, the sanlock package has been added to the vdsm subchannel

for supported usage in Red Hat Enterprise Virtualization. As a result, sanlock
is now installed along with the vdsm package. (BZ#837095)

• The fence-sanlock subpackage has been added. It provides a fence agent, that

uses the sanlock and wdmd packages, along with the ability of wdmd to run
scripts as tests. (BZ#858964)

All users of sanlock are advised to upgrade to these updated packages, which fix
these bugs and add these enhancements.

Solution

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/knowledge/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64

Fixes

• BZ - 826022 - sanlock: should support graceful release of resources
• BZ - 830736 - sanlock: race beween add_lockspace and rem_lockspace
• BZ - 830848 - sanlock: initscript should create /var/lock/subsys/sanlock
• BZ - 831906 - sanlock: segfault with SANLOCKOPTS="-w 0" configuration
• BZ - 832935 - sanlock: softdog module should be loaded in case no watchdog driver was loaded
• BZ - 840063 - sanlock: fix inquire lver
• BZ - 843073 - Add the io_timeout to the lockspace api, and make it safe to adjust.

CVEs

(none)

References

(none)