Re: [Qemu-block] [PATCH 1/6] qcow2: use one single memory block for the L2/refcount cache tables

[Alberto Garcia]

On Tue 05 May 2015 01:20:19 PM CEST, Kevin Wolf wrote:

> Though looking at the code again I see now that c->table_size isn't
> consistently used. The I/O requests still use s->cluster_size. We
> should either use it everywhere or not introduce it at all.

c->table_size is necessary in order to calculate the offset of a
particular table, because s->cluster_size is not always available
(e.g. qcow2_cache_entry_mark_dirty()). We could make it a requirement of
the API, though.

Alternatively we could have c->bs instead of c->table_size. That would
spare us from passing the BlockDriverState pointer to all qcow2_cache_
functions.

The assumption would be that the BlockDriverState pointer is the same
for the whole lifetime of the cache, but that's always guaranteed to be
like that, right?

Berto