This was a very hard to trigger race condition.

If we got a state packet from the peer, after drbd_nl_disk() has
already changed the disk state to D_NEGOTIATING but
after_state_ch() was not yet run by the worker, then receive_state()
might called drbd_sync_handshake(), which in turn crashed
when accessing p_uuid.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

using the global printk_ratelimit() may mask other messages.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

It seems to improve performance if we allow the "p_data" header in its
own frame (no MSG_MORE), but sendpage all but the last page with MSG_MORE.
This is also in preparation of a later zero copy receive implementation.

Suggested by Eduard.Guzovsky@stratus.com on drbd-dev.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

The late-UUID writing is delayed until the next release.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Got introduces with

commit 0c3f3451
Author: Philipp Reisner <philipp.reisner@linbit.com>
Date:   Mon May 17 16:10:43 2010 +0200

    drbd: Create new current UUID as late as possible
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

The choice was to either delay creation of the new UUID until
IO got thawed or to delay it until the first IO request.

Both are correct, the later is more friendly to users of
dual-primary setups, that actually only write on one side.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

This should allow for better performance if the lower level IO stack
of the peers differs in limits exposed either via the queue,
or via some merge_bvec_fn.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

* Only send delay_probes with protocol 93 or newer
* drbd_send_delay_probes() is called only from worker context,
  no atomic_t needed for delay_seq
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

* Mention P_DELAY_PROBE in the packet naming array
* Do not corrupt the mdev->data.work list in case the timer goes
  off before delay_probe_work got handled by the worker
* Do not mod_timer() twice for a single delay_probe pair
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>

Delay_probes are new packets in the DRBD protocol, which allow
DRBD to know the current delay packets have on the data socket.
(relative to the meta data socket)
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>

In case both nodes are "inconsistent", invalidate would
have started a resync anyways, without a chance to ever
succeed, just filling the logs with warning messages.

Simply disallow that state change,
re-using the SS_NO_UP_TO_DATE_DISK return value.

This also changes the corresponding error string to
"Need access to UpToDate Data" -- I found the
"Refusing to be Primary without at least one UpToDate disk"
answer misleading in some situations anyways.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

commit e4f925e1
Author: Philipp Reisner <philipp.reisner@linbit.com>
Date:   Wed Mar 17 14:18:41 2010 +0100

    drbd: Do not upgrade state to Outdated if already Inconsistent

prevented the necessary state transition for attaching while connected
(Diskless -> Consistent respectively Outdated).
This is the fix for the fix.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

There was a race condition:
  In a situation with a SyncSource+Primary and a SyncTarget+Secondary node,
  and a resync dependency to some other device. After both nodes decided
  to do the resync, the other device finishes its resync process.
  At that time SyncSource already sent the P_SYNC_UUID packet, and
  already updated its peer disk state to Inconsistent.
  The SyncTarget node waits for the P_SYNC_UUID and sends a state packet
  to report the resync dependency change. That packet still carries
  a disk state of Outdated.

Impact:
  If application writes come in, during that time on the Primary node,
  those do not get replicated, and the out-of-sync counter gets increased.
  => The completion of resync is not detected on the primary node.
  => stalled.
  Those blocks get resync'ed with the next resync, since the are get
  marked as out-of-sync in the bitmap.

In order to fix this, we filter out that wrong state change in the
sanitize_state() function.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

To document that we know about deprecation of proc_create,
even though we are not affected, as we don't use the ->data member,
open code proc_create_data(..., NULL);
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

We leak memory if "--dry-run" is not supported by the peer.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Fixes a race and potential kernel panic if e.g. the worker was just
about to send a few P_RS_IS_IN_SYNC via the meta socket for checksum
based resync, while the receiver destroys the sockets in
drbd_disconnect.

To make sure no-one is using the meta socket,
it is not enough to stop the asender...
Grab the meta socket mutex before destroying it.
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>

blk_queue_make_request() internally calls blk_set_default_limits(),
so calling blk_queue_max_segment_size() before is useless.
Ergo: move the call to blk_queue_max_segment_size() down a few lines.

Impact:
If, after a fresh modprobe, you first connect a Diskless drbd,
then attach, this could result in a DRBD Protocol Error at first.
The next connection attempt would then succeeded.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

In D_DISKLESS we do not hand out any new references to ldev (local_cnt)
therefore waiting until all previously handed out refereces got returned
is sufficient before actually freeing mdev->ldev.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Remove unused #include <linux/version.h>('s) in
  drivers/block/drbd/drbd_main.c
  drivers/block/drbd/drbd_receiver.c
  drivers/block/drbd/drbd_worker.c
Signed-off-by: NHuang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

rsp->count is unsigned so the test does not work.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Signed-off-by: NEmese Revfy <re.emese@gmail.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

rsp->count is unsigned so the test does not work.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

When IO gets frozen due to a broken fence-peer script, the user
should be able to thaw IO by the resume-io command.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

They should be reimplemented in the current scheme.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

It is force-included on the gcc command line since at least 2.6.15.
Explicit include lines seem to break compilation now in certain configurations.
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NKamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: NSam Ravnborg <sam@ravnborg.org>

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