Folks, looks like we have a funny failure mode: we invalidate buffers only
upon close(), right? Well, going through the partition table happens
without open(). So consider the following scenario:
we insmod the driver foo.
it reads partition table for /dev/foo, doing it via bread() and
populating the page cache.
we rmmod it.
change the disk.
insmod again.
oops, we got stale buffer_heads.
Notice that if we actually _did_ something with /dev/foo we would get a
invalidate_buffers() upon closing it. However, even that is not guaranteed
if we only used a partition - it will get invalidate_buffers(), but
partition tables will not.
Options: short-term one - do invalidation in cleanup_module() (some
drivers do, some don't); possibly better variant - don't bother with
buffer cache in partition parsing. For now I'ld go for the former -
implementing the latter will not change interface, so it can be done more
or less at leisure... Comments?
Cheers,
Al
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