Where "arbitrary" size is currently 1 MiB, which is the BIO_MAX_SIZE
for architectures with 4k PAGE_CACHE_SIZE (most).
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

We want to avoid bio_split for bios crossing activity log boundaries.
So we may need to activate two activity log extents "atomically".
drbd_al_begin_io() needs to know more than just the start sector.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

This is also checked further below in the same function.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Opening a device only succeeds on a primary node, or when explicitly
setting the allow_oos module parameter to allow opening the device
read-only on a secondary node.  There is no other way that a request can
get into drbd_make_request(), so this code cannot trigger.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

The previous algorithm for dealing with overlapping concurrent writes
was generating unnecessary warnings for scenarios which could be
legitimate, and did not always handle partially overlapping requests
correctly.  Improve it algorithm as follows:

* While local or remote write requests are in progress, conflicting new
  local write requests will be delayed (commit 82172f7).

* When a conflict between a local and remote write request is detected,
  the node with the discard flag decides how to resolve the conflict: It
  will ask its peer to discard conflicting requests which are fully
  contained in the local request and retry requests which overlap only
  partially.  This involves a protocol change.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

fold
	if (x >= (N+1))
		return 0;
	if (x < N)
		return 0;
into
	if (x != N)
		return 0;
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Before submitting a new local write request, wait for any conflicting
local or remote requests to complete.

We could assume that the new request occurred first and that the
conflicting requests overwrote it (and therefore discard the new
reques), but we know for sure that the new request occurred after the
conflicting requests and so this behavior would we weird.  We would also
end up with the wrong result if the new request is not fully contained
within the conflicting requests.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Nothing in this function accesses mdev->tconn->net_conf, so there is no
need for get_net_conf() / put_net_conf() anymore.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Instead of keeping a separate tree for local and remote write requests
for finding requests and for conflict detection, use the same tree for
both purposes.  Introduce a flag to allow distinguishing the two
possible types of entries in this tree.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

This flag is set when a processes puts itself to sleep to wait for a
conflicting request to complete.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Move drbd_update_congested() to drbd_main.c, and drbd_req_new() and
drbd_req_free() to drbd_req.c: those functions are not used anywhere
else.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

sed -i \
       -e 's/mdev->req_lock/mdev->tconn->req_lock/g' \
       -e 's/mdev->unused_spare_tle/mdev->tconn->unused_spare_tle/g' \
       -e 's/mdev->newest_tle/mdev->tconn->newest_tle/g' \
       -e 's/mdev->oldest_tle/mdev->tconn->oldest_tle/g' \
       -e 's/mdev->out_of_sequence_requests/mdev->tconn->out_of_sequence_requests/g' \
       *.[ch]
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

sed -i \
       -e 's/mdev->agreed_pro_version/mdev->tconn->agreed_pro_version/g' \
       -e 's/mdev->last_received/mdev->tconn->last_received/g' \
       -e 's/mdev->ko_count/mdev->tconn->ko_count/g' \
       *.[ch]
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Patch mostly:

sed -i -e 's/mdev->data/mdev->tconn->data/g' \
       -e 's/mdev->meta/mdev->tconn->meta/g' \
       *.[ch]
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Patch partly generated by:

sed -i -e 's/get_net_conf(mdev)/get_net_conf(mdev->tconn)/g' \
       -e 's/put_net_conf(mdev)/put_net_conf(mdev->tconn)/g' \
       -e 's/get_net_conf(odev)/get_net_conf(odev->tconn)/g' \
       -e 's/put_net_conf(odev)/put_net_conf(odev->tconn)/g' \
       *.[ch]
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Besides moving the struct member, everything else is generated by:

sed -i -e 's/mdev->net_conf/mdev->tconn->net_conf/g' \
       -e 's/odev->net_conf/odev->tconn->net_conf/g' \
       *.[ch]
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

We do not do collision detection for read requests, but we still need to
look up the request objects when we receive a package over the network.
Using the same data structure for read and write requests results in
simpler code once the tl_hash and app_reads_hash tables are removed.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Found these with the help of ispell -l.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

It is no longer sufficient to trigger on local WRITE,
we need to check on (rq_state & RQ_IN_ACT_LOG)
before calling drbd_al_complete_io also in the error path.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NOr Gerlitz <ogerlitz@voltaire.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

When we receive a barrier ack, we walk the ring list of drbd requests
in the transfer log of the respective epoch, do some housekeeping,
and free those objects.

We tried to keep epochs of mirrored and unmirrored drbd requests
separate, and assert that no local-only requests are present in a
barrier_acked epoch.

It turns out that this has quite a number of corner cases and would
add bloated code without functional benefit.

We now revert the (insufficient) commits
 drbd: Fixed an issue with AHEAD -> SYNC_SOURCE transitions
 drbd: Ensure that an epoch contains only requests of one kind
and instead fix the processing of barrier acks to cope with
a mix of local-only and mirrored requests.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

The assert in drbd_req.c:755 forces us to have only requests of
one kind in an epoch. The two kinds we distinguish here are:
local-only or mirrored.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

We may not get from SyncSource to Ahead if we have sent some
P_RS_DATA_REPLY packets to the peer and are waiting for
P_WRITE_ACK.

Again, this is not relevant for proper tuned systems, but makes
sure that the not-tuned system does not get diverging bitmaps.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>