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>
This commit is contained in:
Philipp Reisner
2013-06-25 16:50:08 +02:00
committed by Jens Axboe
parent e96c96333f
commit d752b26960
8 changed files with 188 additions and 53 deletions

View File

@@ -181,6 +181,8 @@ GENL_struct(DRBD_NLA_RESIZE_PARMS, 7, resize_parms,
__u64_field(1, DRBD_GENLA_F_MANDATORY, resize_size)
__flg_field(2, DRBD_GENLA_F_MANDATORY, resize_force)
__flg_field(3, DRBD_GENLA_F_MANDATORY, no_resync)
__u32_field_def(4, 0 /* OPTIONAL */, al_stripes, DRBD_AL_STRIPES_DEF)
__u32_field_def(5, 0 /* OPTIONAL */, al_stripe_size, DRBD_AL_STRIPE_SIZE_DEF)
)
GENL_struct(DRBD_NLA_STATE_INFO, 8, state_info,