[Cluster-devel] Recording extents in GFS2

[Bob Peterson <rpeterso@redhat.com>]

----- Original Message -----
> >> once we change the journal format, in addition to recording block numbers
> >> as extents, there are some additional issues we should address at the same
> >> time:

One thing I've always thought we should improve upon was the way we manage
our bitmaps. Right now, if you allocate or free a block, unless it's on the
first block of the rgrp, we need to write two blocks: (1) One for the bitmap
that needs to change and, (2) Another for the rgrp to adjust its allocated and
free numbers. The rgrplvb code will make this faster, but it would be nice if
we would somehow keep "version 2" bitmaps such that each keeps its own statistics.

That way we only need to journal and write the affected bitmap, and not
necessarily its rgrp block as well. I could see us keep separate glocks
for each bitmap, for example, and allowing multiple nodes to work on the
same portion of the file system, but on unique bitmaps.

Bob