drbd: Allow online change of al-stripes and al-stripe-size
Allow to change the AL layout with an resize operation. For that
the reisze command gets two new fields: al_stripes and al_stripe_size.
In order to make the operation crash save:
1) Lock out all IO and MD-IO
2) Write the super block with MDF_PRIMARY_IND clear
3) write the bitmap to the new location (all zeros, since
we allow only while connected)
4) Initialize the new AL-area
5) Write the super block with the restored MDF_PRIMARY_IND.
6) Unfreeze all IO
Since the AL-layout has no influence on the protocol, this operation
needs to be beforemed on both sides of a resource (if intended).
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/drbd_limits.h b/include/linux/drbd_limits.h
index 1fedf2b..17e50bb 100644
--- a/include/linux/drbd_limits.h
+++ b/include/linux/drbd_limits.h
@@ -215,4 +215,13 @@
#define DRBD_ALWAYS_ASBP_DEF 0
#define DRBD_USE_RLE_DEF 1
+#define DRBD_AL_STRIPES_MIN 1
+#define DRBD_AL_STRIPES_MAX 1024
+#define DRBD_AL_STRIPES_DEF 1
+#define DRBD_AL_STRIPES_SCALE '1'
+
+#define DRBD_AL_STRIPE_SIZE_MIN 4
+#define DRBD_AL_STRIPE_SIZE_MAX 16777216
+#define DRBD_AL_STRIPE_SIZE_DEF 32
+#define DRBD_AL_STRIPE_SIZE_SCALE 'k' /* kilobytes */
#endif