linux-toradex.git/drivers/block/drbd/drbd_req.c, branch v3.6.1

drbd: Finish requests that completed while IO was frozen

2012-08-16T15:14:45+00:00

Requests of an acked epoch are stored on the barrier_acked_requests list. In
case the private bio of such a request completes while IO on the drbd device
is suspended [req_mod(completed_ok)] then the request stays there.

When thawing IO because the fence_peer handler returned, then we use
tl_clear() to apply the connection_lost_while_pending event to all requests
on the transfer-log and the barrier_acked_requests list.

Up to now the connection_lost_while_pending event was not applied
on requests on the barrier_acked_requests list. Fixed that.

I.e. now the connection_lost_while_pending and resend events are
applied to requests on the barrier_acked_requests list. For that
it is necessary that the resend event finishes (local only)
READS correctly.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: fix drbd wire compatibility for empty flushes

2012-08-16T15:12:56+00:00

DRBD has a concept of request epochs or reorder-domains,
which are separated on the wire by P_BARRIER packets.

Older DRBD is not able to handle zero-sized requests at all,
so we need to map empty flushes to these drbd barriers.

These are the equivalent of empty flushes, and
by default trigger flushes on the receiving side anyways
(unless not supported or explicitly disabled),
so there is no need to handle this differently in newer drbd either.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: announce FLUSH/FUA capability to upper layers

2012-07-24T13:14:28+00:00

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 
Signed-off-by: Lars Ellenberg

drbd: differentiate between normal and forced detach

2012-07-24T12:06:18+00:00

Aborting local requests (not waiting for completion from the lower level
disk) is dangerous: if the master bio has been completed to upper
layers, data pages may be re-used for other things already.
If local IO is still pending and later completes,
this may cause crashes or corrupt unrelated data.

Only abort local IO if explicitly requested.
Intended use case is a lower level device that turned into a tarpit,
not completing io requests, not even doing error completion.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: fix null pointer dereference with on-congestion policy when diskless

2012-06-12T12:35:19+00:00

We must not look at mdev->actlog, unless we have a get_ldev() reference.
It also does not make much sense to try to disconnect or pull-ahead of
the peer, if we don't have good local data.

Only even consider congestion policies, if our local disk is D_UP_TO_DATE.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: fix list corruption by failing but already aborted reads

2012-06-12T12:34:51+00:00

If a read is aborted due to force-detach of a supposedly unresponsive
local backing device, and retried on the peer, it can happen that the
local request later still completes (hopefully with an error).
As it may already have been completed to upper layers meanwhile,
it must not be retried again now.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: Restore the request restart logic

2012-05-09T15:20:59+00:00

It got lost with the commit 5a7bbad27a410350e64a2d7f5ec18fc73836c14f
"block: remove support for bio remapping from ->make_request"

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: fix resend/resubmit of frozen IO

2012-05-09T13:16:58+00:00

DRBD can freeze IO, due to fencing policy (fencing resource-and-stonith),
or because we lost access to data (on-no-data-accessible suspend-io).

Resuming from there (re-connect, or re-attach, or explicit admin
intervention) should "just work".

Unfortunately, if the re-attach/re-connect did not happen within
the timeout, since the commit
  drbd: Implemented real timeout checking for request processing time
if so configured, the request_timer_fn() would timeout and
detach/disconnect virtually immediately.

This change tracks the most recent attach and connect, and does not
timeout within  after attach/connect.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: move put_ldev from __req_mod() to the endio callback

2012-05-09T13:16:51+00:00

One invocation in the endio handler is good enough,
we don't need mention it for each of the different ways
it calls __req_mod().

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: fix WRITE_ACKED_BY_PEER_AND_SIS to not set RQ_NET_DONE

2012-05-09T13:16:50+00:00

Just because this request happened during a resync does
not mean it may pretend to have been barrier-acked.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg