Adding requests to per-device fifo lists as soon as possible after
allocating them leaves a simple list_first_entry_or_null() to find the
oldest request, regardless what it is still waiting for.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Record (in jiffies) how much time a request spends in which stages.
Followup commits will use and present this additional timing information
so we can better locate and tackle the root causes of latency spikes,
or present the backlog for asynchronous replication.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

For diagnostic purposes, track intent, start time
and latest submit time of meta data IO.

Move separate members from struct drbd_device
into the embeded struct drbd_md_io.
s/md_io_(page|in_use)/md_io.\1/
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

drbd_destroy_device means to give up reference counts
on the connection(s) reachable via the peer_device(s).

It must not do that by iterating via device->resource->connections,
resource and connections may have already been disassociated
by drbd_free_resource, and we'd leak connection refs.

Instead, iterate via device->peer_devices->connection.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Now that we have additional asynchronous kref_get/kref_put
via debugfs, make sure we catch access after free.

Poison struct drbd_device, drbd_connection and drbd_resource
before kfree() with 0xfd, 0xfc, and 0xf2, respectively.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

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

If "dirty" blocks are written to during resync,
that brings them in-sync.

By explicitly requesting write-acks during resync even in protocol != C,
we now can actually respect this.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Get rid of dump_stack() debug statements.

There is no point whatsoever in registering and unregistering a reboot
notifier that doesn't do anything.

The intention was to switch to an "emergency read-only" mode,
so we won't have to resync the full activity log just because
we had been Primary before the reboot.

Once we have that implemented, we may re-introduce the reboot notifier.
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 replaces the md_sync_work member of struct drbd_device
by a new MD_SYNC "work bit" in device->flags.

This replaces the resync_start_work member of struct drbd_device
by a new RS_START "work bit" in device->flags.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

The recent fix to put_ldev() (correct ordering of access to local_cnt
and state.disk; memory barrier in __drbd_set_state) guarantees
that the cleanup happens exactly once.

However it does not yet guarantee that the cleanup happens from worker
context, the last put_ldev() may still happen from atomic context,
which must not happen: blkdev_put() may sleep.

Fix this by scheduling the cleanup to the worker instead,
using a couple more bits in device->flags and a new helper,
drbd_device_post_work().

Generalized the "resync progress" work to cover these new work bits.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

This should reduce latency for such in-DRBD-protocol "pings",
and may help reduce spurious disconnect/reconnect cycles due to
 "PingAck did not arrive in time."
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Since the member of drbd_device is called ldev
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Some parts of the code assumed that get_ldev_if_state(device, D_ATTACHING)
is sufficient to access the ldev member of the device object. That was
wrong. ldev may not be there or might be freed at any time if the device
has a disk state of D_ATTACHING.

bm_rw()
  Documented that drbd_bm_read() is only called from drbd_adm_attach.
  drbd_bm_write() is only called when a reference is held, and it is
  documented that a caller has to hold a reference before calling
  drbd_bm_write()

drbd_bm_write_page()
  Use get_ldev() instead of get_ldev_if_state(device, D_ATTACHING)

drbd_bmio_set_n_write()
  No longer use get_ldev_if_state(device, D_ATTACHING). All callers
  hold a reference to ldev now.

drbd_bmio_clear_n_write()
  All callers where holding a reference of ldev anyways. Remove the
  misleading get_ldev_if_state(device, D_ATTACHING)

drbd_reconsider_max_bio_size()
  Removed the get_ldev_if_state(device, D_ATTACHING). All callers
  now pass a struct drbd_backing_dev* when they have a proper
  reference, or a NULL pointer.
  Before this fix, the receiver could trigger a NULL pointer
  deref when in drbd_reconsider_max_bio_size()

drbd_bump_write_ordering()
  Used get_ldev_if_state(device, D_ATTACHING) with the wrong assumption.
  Remove it, and allow the caller to pass in a struct drbd_backing_dev*
  when the caller knows that accessing this bdev is safe.
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>

Note that I do NOT call __drbd_chk_io_error for failed REQ_DISCARD.
That may be wrong, though, or needs to differ between EOPNOTSUPP and
other errors...
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

We plan to use genl_family->parallel_ops = true in the future,
but need to review all possible interactions first.

For now, only selectively drop genl_lock() in drbd_set_role(),
instead serializing on our own internal resource->conf_update mutex.

We now can be promoted/demoted on many resources in parallel,
which may significantly improve cluster failover times
when fencing is required.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Because all administrative requests via genetlink have been globally
serialized via genl_lock(), we used to have one static struct
drbd_config_context "admin context".

Move this on-stack to the respective callback functions.

This will allow us to selectively drop the genl_lock()
(or use genl_family->parallel_ops) in the future.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

In the drbd_thread "infrastructure" functions, only use the resource instead of
the connection.  Make the connection field of drbd_thread optional.  This will
allow to introduce threads which are not associated with a connection.
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

The new function can flush any work queue, not just the work queue of the data
socket of a connection.
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

drbd_device_work is a work item that has a reference to a device,
while drbd_work is a more generic work item that does not carry
a reference to a device.

All callbacks get a pointer to a drbd_work instance, those callbacks
that expect a drbd_device_work use the container_of macro to get it.
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

These functions actually operate on a peer device, or
need a peer device.

drbd_prepare_command(), drbd_send_command(), drbd_send_sync_param()
drbd_send_uuids(), drbd_gen_and_send_sync_uuid(), drbd_send_sizes()
drbd_send_state(), drbd_send_current_state(), and drbd_send_state_req()
drbd_send_sr_reply(), drbd_send_ack(), drbd_send_drequest(),
drbd_send_drequest_csum(), drbd_send_ov_request(), drbd_send_dblock()
drbd_send_block(), drbd_send_out_of_sync(), recv_dless_read()
drbd_drain_block(), receive_bitmap_plain(), recv_resync_read()
read_in_block(), read_for_csum(), drbd_alloc_pages(), drbd_alloc_peer_req()
need_peer_seq(), update_peer_seq(), wait_for_and_update_peer_seq()
drbd_sync_handshake(), drbd_asb_recover_{0,1,2}p(), drbd_connected()
drbd_disconnected(), decode_bitmap_c() and recv_bm_rle_bits()
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Also fix drbd_calc_cpu_mask() to spread resources equally over all online cpus
independent of device minor numbers.
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

in drbd_adm_down(), drbd_create_device() and drbd_set_role()
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

The implicit dependency on a variable inside the macro is problematic.
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

With the polymorphic drbd_() macros, we no longer need the connection
specific variants.
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

DRBD was using dev_err() and similar all over the code; instead of having to
write dev_err(disk_to_dev(device->vdisk), ...) to convert a drbd_device into a
kernel device, a DEV macro was used which implicitly references the device
variable.  This is terrible; introduce separate drbd_err() and similar macros
with an explicit device parameter instead.
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Let connection->peer_devices point to peer devices; connection->volumes was
pointing to devices.
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

So far, connections and resources always come in pairs, but in the future with
multiple connections per resource, the names will stick with the resources.
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

This allows to access the volumes of a resource by number.
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>