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>
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 60c89e5..ee19ba2 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -755,6 +755,14 @@
s32 al_offset; /* signed relative sector offset to activity log */
s32 bm_offset; /* signed relative sector offset to bitmap */
+
+ /* cached value of bdev->disk_conf->meta_dev_idx (see below) */
+ s32 meta_dev_idx;
+
+ /* see al_tr_number_to_on_disk_sector() */
+ u32 al_stripes;
+ u32 al_stripe_size_4k;
+ u32 al_size_4k; /* cached product of the above */
};
struct drbd_backing_dev {
@@ -1862,38 +1870,24 @@
}
/**
- * drbd_md_ss__() - Return the sector number of our meta data super block
- * @mdev: DRBD device.
+ * drbd_md_ss() - Return the sector number of our meta data super block
* @bdev: Meta data block device.
*/
-static inline sector_t drbd_md_ss__(struct drbd_conf *mdev,
- struct drbd_backing_dev *bdev)
+static inline sector_t drbd_md_ss(struct drbd_backing_dev *bdev)
{
- int meta_dev_idx;
+ const int meta_dev_idx = bdev->md.meta_dev_idx;
- rcu_read_lock();
- meta_dev_idx = rcu_dereference(bdev->disk_conf)->meta_dev_idx;
- rcu_read_unlock();
-
- switch (meta_dev_idx) {
- default: /* external, some index; this is the old fixed size layout */
- return MD_128MB_SECT * meta_dev_idx;
- case DRBD_MD_INDEX_INTERNAL:
- /* with drbd08, internal meta data is always "flexible" */
- case DRBD_MD_INDEX_FLEX_INT:
- if (!bdev->backing_bdev) {
- if (__ratelimit(&drbd_ratelimit_state)) {
- dev_err(DEV, "bdev->backing_bdev==NULL\n");
- dump_stack();
- }
- return 0;
- }
- /* sizeof(struct md_on_disk_07) == 4k
- * position: last 4k aligned block of 4k size */
- return (drbd_get_capacity(bdev->backing_bdev) & ~7ULL) - 8;
- case DRBD_MD_INDEX_FLEX_EXT:
+ if (meta_dev_idx == DRBD_MD_INDEX_FLEX_EXT)
return 0;
- }
+
+ /* Since drbd08, internal meta data is always "flexible".
+ * position: last 4k aligned block of 4k size */
+ if (meta_dev_idx == DRBD_MD_INDEX_INTERNAL ||
+ meta_dev_idx == DRBD_MD_INDEX_FLEX_INT)
+ return (drbd_get_capacity(bdev->backing_bdev) & ~7ULL) - 8;
+
+ /* external, some index; this is the old fixed size layout */
+ return MD_128MB_SECT * bdev->md.meta_dev_idx;
}
static inline void
