[Cluster-devel] [PATCH][GFS2] Given device ID rather than s_id in "id" sysfs file

[Bob Peterson]

On Fri, 2007-11-02 at 09:55 -0500, David Teigland wrote:
> We have to be extremely cautious when changing the kernel abi like this;
> have you verified that it doesn't break any existing programs?

Dave has a good point here.  I've verified that no other gfs2 util
uses the "id" except for gfs2_tool.  However, this kernel change
makes previous userland versions of gfs2_tool stop working in some
cases, for example, gfs2_tool gettune and settune.
Customers would need to upgrade their gfs2_tool to use the new
gfs2 kernel module.

For that reason, perhaps we should revert this patch and instead
export the device id to a separate /sys/fs file called
/sys/fs/gfs2/<s_id>/device_id or some such.  That would ensure
backward compatibility with older userland tools.

BTW, this also led me to discover that the gfs2 quota tool
uses /sys/fs/gfs2/<lock table>/xxx which, in the case of stand-alone
file systems, would be a NULL string.  The quota tool should
be changed to use the same interface as gfs2_tool to determine
the proper path in sysfs.  Perhaps I'll open a bugzilla record on it.

Regards,

Bob Peterson
Red Hat Cluster Suite