drbd: prepare for new striped layout of activity log
authorLars Ellenberg <lars.ellenberg@linbit.com>
Tue, 19 Mar 2013 17:16:44 +0000 (18:16 +0100)
committerJens Axboe <axboe@kernel.dk>
Sat, 23 Mar 2013 00:13:59 +0000 (18:13 -0600)
commit3a4d4eb3cb03fbc66696fc8cd472701d56f3aee7
tree06a5d9a18bb35f23e68c3cca745f28b3f409e41c
parentae8bf312e97d554b6aa32e7b2ceb993812ad0835
drbd: prepare for new striped layout of activity log

Introduce two new on-disk meta data fields: al_stripes and al_stripe_size_4k
The intended use case is activity log on RAID 0 or similar.
Logically consecutive transactions will advance their on-disk position
by al_stripe_size_4k 4kB (transaction sized) blocks.

Right now, these are still asserted to be the backward compatible
values al_stripes = 1, al_stripe_size_4k = 8 (which amounts to 32kB).

Also introduce a caching member for meta_dev_idx in the in-core
structure: even though it is initially passed in in the rcu-protected
disk_conf structure, it cannot change without a detach/attach cycle.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
drivers/block/drbd/drbd_actlog.c
drivers/block/drbd/drbd_int.h
drivers/block/drbd/drbd_main.c
drivers/block/drbd/drbd_nl.c