drbd: announce FLUSH/FUA capability to upper layers
Unconditionally announce FLUSH/FUA to upper layers.
If the lower layers on either node do not actually support this,
generic_make_request() will deal with it.
If this causes performance regressions on your setup,
make sure there are no volatile caches involved,
and mount -o nobarrier or equivalent.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 83d9913..c74ca2d 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -277,6 +277,9 @@
atomic_t *a = is_net ? &mdev->pp_in_use_by_net : &mdev->pp_in_use;
int i;
+ if (page == NULL)
+ return;
+
if (drbd_pp_vacant > (DRBD_MAX_BIO_SIZE/PAGE_SIZE)*minor_count)
i = page_chain_free(page);
else {
@@ -316,7 +319,7 @@
gfp_t gfp_mask) __must_hold(local)
{
struct drbd_epoch_entry *e;
- struct page *page;
+ struct page *page = NULL;
unsigned nr_pages = (data_size + PAGE_SIZE -1) >> PAGE_SHIFT;
if (drbd_insert_fault(mdev, DRBD_FAULT_AL_EE))
@@ -329,9 +332,11 @@
return NULL;
}
- page = drbd_pp_alloc(mdev, nr_pages, (gfp_mask & __GFP_WAIT));
- if (!page)
- goto fail;
+ if (data_size) {
+ page = drbd_pp_alloc(mdev, nr_pages, (gfp_mask & __GFP_WAIT));
+ if (!page)
+ goto fail;
+ }
INIT_HLIST_NODE(&e->collision);
e->epoch = NULL;
@@ -1270,7 +1275,6 @@
data_size -= dgs;
- ERR_IF(data_size == 0) return NULL;
ERR_IF(data_size & 0x1ff) return NULL;
ERR_IF(data_size > DRBD_MAX_BIO_SIZE) return NULL;
@@ -1291,6 +1295,9 @@
if (!e)
return NULL;
+ if (!data_size)
+ return e;
+
ds = data_size;
page = e->pages;
page_chain_for_each(page) {
@@ -1715,6 +1722,10 @@
dp_flags = be32_to_cpu(p->dp_flags);
rw |= wire_flags_to_bio(mdev, dp_flags);
+ if (e->pages == NULL) {
+ D_ASSERT(e->size == 0);
+ D_ASSERT(dp_flags & DP_FLUSH);
+ }
if (dp_flags & DP_MAY_SET_IN_SYNC)
e->flags |= EE_MAY_SET_IN_SYNC;
