After disconnect (most likely mdev->net_cnt == 0) and we are
still in an unstable state (!drbd_state_is_stable()). When we
get an IO request in drbd_get_max_buffers() (called from
__inc_ap_bio_cond(), called from inc_ap_bio()) we wake up
misc_wait. Misc_wait is also used in inc_ap_bio() to sleep
until the outcome of __inc_ap_bio_cond() changes. => Busy loop!

Solution: Have a dedicated wait queue for get_net_conf() and
put_net_conf().
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Make sure the state engine can deny two primaries to connect
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>

Since we can not thaw the transfer log, the next logical step is
to allow reconnects while the fence-peer handler runs.
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>

If IO was frozen for a temporal network outage, resend the
content of the transfer-log into the newly established connection.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

With that the drbd_fail_pending_reads() function becomes obsolete.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

It was a now abandoned attempt to throttle resync bandwidth
based on the delay it causes on the bulk data socket.
It has no userbase yet, and has been disabled by
9173465ccb51c09cc3102a10af93e9f469a0af6f already.
This removes the now unused code.

The basic feature, namely using up "idle" bandwith
of network and disk IO subsystem, with minimal impact
to application IO, is being reimplemented differently.
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>

Remove the current bio flags and reuse the request flags for the bio, too.
This allows to more easily trace the type of I/O from the filesystem
down to the block driver.  There were two flags in the bio that were
missing in the requests:  BIO_RW_UNPLUG and BIO_RW_AHEAD.  Also I've
renamed two request flags that had a superflous RW in them.

Note that the flags are in bio.h despite having the REQ_ name - as
blkdev.h includes bio.h that is the only way to go for now.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

drbd/drbd_receiver.c: linux/mm.h is included more than once.
Signed-off-by: NAndrea Gelmini <andrea.gelmini@gelma.net>
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>

quoting tcp(7):
    On individual connections, the socket buffer size must be set prior to the
    listen(2) or connect(2) calls in order to have it take effect.

This adds a wrapper to do so, and uses it appropriately.
Improves performance in certain situations.

Note that because we cannot easily determine which socket will be
"meta" and wich "data" (bulk) socket, we adjust both sockets.
Previously, DRBD only adjusted the bufsizes of the "data" socket.

Thanks again to Eduard.Guzovsky@stratus.com.
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>

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>

Now that the peer may handle multi-bio EEs,
we can ignore the peer's limit,
and concentrate on the limits of the local IO stack.

This is safe accross drbd protocol versions,
as our queue_max_sectors() will be adjusted accordingly.
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>

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>

Some wish to be notified of all instances of split brain, not just those that
go unresolved.  The initial-split-brain handler is called to notify someone
upon  detection of all split brain conditions even if auto-recovery policies
are configured.
Signed-off-by: NAdam Gandelman <adam.gandelman@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Even if it should never happen if the peer does behave, we need to
double check, and not even attempt access beyond end of device.
It usually would be caught by lower layers, resulting in "IO error",
but may also end up in the internal meta data area.
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>

Don't forget to drain the digest in case we cannot satisfy a
checksum based resync or online-verify request.

It would additionally cause a protocoll error,
dropping the connection.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

block_id may be ID_SYNCER,
as well as checksum based resync request magic, or online verify magic.

Let's just drop that ASSERT.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

The patch just convert all blkdev_issue_xxx function to common
set of flags. Wait/allocation semantics preserved.
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
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>

This mitigates changes introduced with commit:
http://git.drbd.org/?p=drbd-8.3.git;a=commit;h=4b6803a3276652da3737Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.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>

Situation:
we have diverging data sets, i.e. we had a split brain somewhen,
but currently are connected, one node diskless.

Then we try to attach that disk, figure it is consistent,
but has a diverging data set, we refuse to attach.

This led to strange state changes:
22:18:35 bb drbd1: peer( Unknown -> Primary ) conn( WFReportParams -> Connected) pdsk( DUnknown -> UpToDate )
22:19:30 bb drbd1: disk( Diskless -> Attaching )
22:19:30 bb drbd1: disk( Attaching -> Negotiating )
22:19:30 bb drbd1: drbd_sync_handshake:
22:19:30 bb drbd1: self 97BF25798B9D5222:F33D1F62ADE698DD:4269796F9D027C83:AC45D8B5C3C1BF93 bits:19449 flags:0
22:19:30 bb drbd1: peer 280DFB6E125465D3:F33D1F62ADE698DC:4269796F9D027C82:AC45D8B5C3C1BF93 bits:2575806 flags:0
22:19:30 bb drbd1: uuid_compare()=100 by rule 90
22:19:30 bb drbd1: Split-Brain detected, dropping connection!
22:19:30 bb drbd1: disk( Negotiating -> Diskless )

while the other side says:
22:19:30 aa drbd1: Split-Brain detected, dropping connection!
22:19:30 aa drbd1: Disk attach process on the peer node was aborted.
22:19:30 aa drbd1: conn( Connected -> TOO_LARGE ) pdsk( Diskless -> Consistent )

This should be fixed now.
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>

epoch is always NULL here.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

drbd: Allow online resizing of DRBD devices while peer not reachable (needs to be explicitly forced)
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>

Test the just-allocated value for NULL rather than some other value.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression x,y;
statement S;
@@

x = \(kmalloc\|kcalloc\|kzalloc\)(...);
(
if ((x) == NULL) S
|
if (
-   y
+   x
       == NULL)
 S
)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Test the just-allocated value for NULL rather than some other value.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression x,y;
statement S;
@@

x = \(kmalloc\|kcalloc\|kzalloc\)(...);
(
if ((x) == NULL) S
|
if (
-   y
+   x
       == NULL)
 S
)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>

Immediately after changing the write ordering method, the epoch can already
be finished at this point.
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>

Since 8.3.3 we fail to do the resync when a partial resynch is not
possible, but a full synch is necessary.

This regression was introduced with 7101539930c0a89146959e7a39c09ad9c3516434
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Otherwise the 'state fixup' in the receiver will change to Unconnected,
but the receiver will terminate itself, and any attempt at 'down'ing
that drbd later will block forever.

see also Bugz. #259
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>