[Cluster-devel] [PATCH][V2] GFS2: Use lvbs for storing rgrp information with mount option

[Bob Peterson]

----- Original Message -----
| Instead of reading in the resource groups when gfs2 is checking
| for free space to allocate from, gfs2 can store the necessary
| infromation
| in the resource group's lvb.  Also, instead of searching for unlinked
| inodes in every resource group that's checked for free space, gfs2
| can
| store the number of unlinked but inodes in the lvb, and only check
| for
| unlinked inodes if it will find some.
| 
| The first time a resource group is locked, the lvb must initialized.
| Since this involves counting the unlinked inodes in the resource
| group,
| this takes a little extra time.  But after that, if the resource
| group
| is locked with GL_SKIP, the buffer head won't be read in unless it's
| actually needed.
| 
| Enabling the resource groups lvbs is done via the rgrplvb mount
| option.  If
| this option isn't set, the lvbs will still be set and updated, but
| they won't
| be verfied or used by the filesystem.  To safely turn on this option,
| all of
| the nodes mounting the filesystem must be running code with this
| patch, and
| the filesystem must have been completely unmounted since they were
| updated.
| 
| Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>

Hi,

Looks good to me.

Bob Peterson
Red Hat File Systems