Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

In case the connection was established and lost again before
the a fence-peer handler returns, ignore the exit code of this
instance. (And use the exit code of the later started instance)
Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NAndreas Gruenbacher <agruen@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We validated resync_after dependencies, if changed via disk-options.
But we did not validate them when first created via attach.
We also did not check or cleanup dependencies that used to be correct,
but now point to meanwhile removed minor devices.

If the drbd_resync_after_valid() validation in disk-options tried to
follow a dependency chain in this way, this could lead to NULL pointer
dereference.

Validate resync_after settings in drbd_adm_attach() already, as well as
in drbd_adm_disk_opts(), and and only reject dependency loops.
Depending on non-existing disks is allowed and equivalent to no dependency.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The issue was that if the connection broke while we did the
gracefull state change to C_DISCONNECTING (C_TEARDOWN), then
we returned a success code from the state engine. (SS_CW_NO_NEED)

The result of that is that we missed to call the fence-peer
script in such a case.

Fixed that by introducing a new error code (SS_OUTDATE_WO_CONN).
This one should never reach back into user space.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Patch best viewed with git diff --ignore-space-change.

Now that we attempt the fallback to local bitmap operation
only when disconnected, we can safely drop the extra "silent"
state request from both invalidate and invalidate-remote.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

To avoid other state change requests, after passing through
sanitize_state(), to be mistaken for an invalidate,
move the "set all bits as out-of-sync" into the invalidate path.

Make invalidate and invalidate-remote behave consistently wrt.
current connection state (need either an established replication link,
or really be disconnected). Also mention that in the documentation.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Now that the on-disk activity-log ring buffer size is adjustable,
the maximum active set can become larger, and is now limited by
the use of 16bit "labels".

This increases the maximum working set from 6433 to 65534 extents,
each of which covers an area of 4MiB.
Which means that if you use the maximum, you'd have to resync
more than 250 GiB after an unclean Primary shutdown.
With capable backend storage and replication links,
this is entirely feasible.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

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

We used to calculate all on-disk meta data offsets, and then compare
the stored offsets, basically treating them as magic numbers.

Now with the activity log striping, the activity log size is no longer
fixed.  We need to first read the super block, then base the activity
log and bitmap offsets on the stored offsets/al stripe settings.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Make it obvious that this value is in units of 512 Byte sectors.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Now we have the cached meta_dev_idx member,
we can get rid of a few rcu_read_lock() sections and rcu_dereference().
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Introduce two new on-disk meta data fields: al_stripes and al_stripe_size_4k
The intended use case is activity log on RAID 0 or similar.
Logically consecutive transactions will advance their on-disk position
by al_stripe_size_4k 4kB (transaction sized) blocks.

Right now, these are still asserted to be the backward compatible
values al_stripes = 1, al_stripe_size_4k = 8 (which amounts to 32kB).

Also introduce a caching member for meta_dev_idx in the in-core
structure: even though it is initially passed in in the rcu-protected
disk_conf structure, it cannot change without a detach/attach cycle.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Add a comment about our meta data layout variants,
and rename a few defines (e.g. MD_RESERVED_SECT -> MD_128MB_SECT)
to make it clear that they are short hand for fixed constants,
and not arbitrarily to be redefined as one may see fit.

Properly pad struct meta_data_on_disk to 4kB,
and initialize to zero not only the first 512 Byte,
but all of it in drbd_md_sync().
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This was introduces when moving the code over from the 8.3 codebase
with commit 328e0f12Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

We need to propagate the configuration into the flag bits,
or it won't be effective.
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>

If we detach due to local read-error (which sets a bit in the bitmap),
stay Primary, and then re-attach (which re-reads the bitmap from disk),
we potentially lost the "out-of-sync" (or, "bad block") information in
the bitmap.

Always (try to) write out the changed bitmap pages before going diskless.

That way, we don't lose the bit for the bad block,
the next resync will fetch it from the peer, and rewrite
it locally, which may result in block reallocation in some
lower layer (or the hardware), and thereby "heal" the bad blocks.

If the bitmap writeout errors out as well, we will (again: try to)
mark the "we need a full sync" bit in our super block,
if it was a READ error; writes are covered by the activity log already.

If that superblock does not make it to disk either, we are sorry.

Maybe we just lost an entire disk or controller (or iSCSI connection),
and there actually are no bad blocks at all, so we don't need to
re-fetch from the peer, there is no "auto-healing" necessary.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Without this, the meta-data gets updates after 5 seconds by the
md_sync_timer. Better to do it immeditaly after a state change.

If the asender detects a network failure, it may take a bit until
the worker processes the according after-conn-state-change work item.

  The worker might be blocked in sending something, i.e. it
  takes until it gets into its timeout. That is 6 seconds by
  default which is longer than the 5 seconds of the md_sync_timer.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

drbd_adm_disk_opts() does
	wait_event(mdev->al_wait, lc_try_lock(mdev->act_log));
	drbd_al_shrink(mdev);

If the device is very busy, this can take a very long time to succeed.
Fix this by temporarily suspending IO,
then quickly change the settings, and resume.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

There is at least the worker context, the receiver context, the context of
receiving netlink packts.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

We need to write the whole bitmap after we moved the meta data
due to an online resize operation.

With the support for one peta byte devices bitmap IO was optimized
to only write out touched pages. This optimization must be turned
off when writing the bitmap after an online resize.

This issue was introduced with drbd-8.3.10.

The impact of this bug is that after an online resize, the next
resync could become larger than expected.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

If for some reason (typically "split-brained" cluster manager)
drbd replica data has diverged, we can chose a victim,
and reconnect using "--discard-my-data", causing the victim
to become sync-target, fetching all changed blocks from the peer.

If we are Primary, we are potentially in use, and we refuse to
"roll back" changes to the data below the page cache and other users.

Rename the error symbol for this to ERR_DISCARD_IMPOSSIBLE.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

We don't discard anything here, really.
We resolve conflicting, concurrent writes to overlapping data blocks.
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 now can schedule only a specific range of sectors for online verify,
or interrupt a running verify without interrupting the connection.

Had to bump the protocol version differently, we are now 101.
Added verify_can_do_stop_sector() { protocol >= 97 && protocol != 100; }

Also, the return value convention for worker callbacks has changed,
we returned "true/false" for "keep the connection up" in 8.3,
we return 0 for success and <= for failure in 8.4.
Affected: receive_state()
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

If you do back to back wait-sync/invalidate on a Primary in a tight loop,
during application IO load, you could trigger a race:
  kernel: block drbd6: FIXME going to queue 'set_n_write from StartingSync'
    but 'write from resync_finished' still pending?

Fix this by changing the order of the drbd_queue_work() and
the wake_up() in dec_ap_pending(), and adding the additional
drbd_flush_workqueue() before requesting the full sync.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Fix asserts like
  block drbd0: in got_BlockAck:4634: rs_pending_cnt = -35 < 0 !

We reset the resync lru cache and related information (rs_pending_cnt),
once we successfully finished a resync or online verify, or if the
replication connection is lost.

We also need to reset it if a resync or online verify is aborted
because a lower level disk failed.

In that case the replication link is still established,
and we may still have packets queued in the network buffers
which want to touch rs_pending_cnt.

We do not have any synchronization mechanism to know for sure when all
such pending resync related packets have been drained.

To avoid this counter to go negative (and violate the ASSERT that it
will always be >= 0), just do not reset it when we lose a disk.

It is good enough to make sure it is re-initialized before the next
resync can start: reset it when we re-attach a disk.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

If the drbd worker thread is synchronously waiting for some userland
callback, we don't want some casual pageout to block on us.
Have drbd_congested() report congestion in that case.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

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

drbd_adm_down() does adm_detach(), which can fail with various error
codes, or be interrupted by a signal.

The interrupted by signal case was not properly handled,
leading to
	block drbd0: ASSERT( mdev->state.disk == D_DISKLESS &&
	                     mdev->state.conn == C_STANDALONE ) in drbd/drbd_worker.c
and further to destroying objects while still in use, and resulting crashes.

Detect the interruption, and take the error path out.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

cherry-picked and adapted from drbd 9 devel branch

DRBD requests (struct drbd_request) are already on the per resource
transfer log list, and carry their epoch number. We do not need to
additionally link them on other ring lists in other structs.

The drbd sender thread can recognize itself when to send a P_BARRIER,
by tracking the currently processed epoch, and how many writes
have been processed for that epoch.

If the epoch of the request to be processed does not match the currently
processed epoch, any writes have been processed in it, a P_BARRIER for
this last processed epoch is send out first.
The new epoch then becomes the currently processed epoch.

To not get stuck in drbd_al_begin_io() waiting for P_BARRIER_ACK,
the sender thread also needs to handle the case when the current
epoch was closed already, but no new requests are queued yet,
and send out P_BARRIER as soon as possible.

This is done by comparing the per resource "current transfer log epoch"
(tconn->current_tle_nr) with the per connection "currently processed
epoch number" (tconn->send.current_epoch_nr), while waiting for
new requests to be processed in wait_for_work().
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

By disabling al-updates one might increase performace. The price for
that is that in case a crashed primary (that had al-updates disabled)
is reintegraded, it will receive a full-resync instead of a bitmap
based resync.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

These macros no longer exist in kernel version v3.5-rc1.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

When a resync or online verify is finished or aborted,
drbd does a bulk write-out of changed bitmap pages.

If *in that very moment* a new verify or resync is triggered,
this can race:
 ASSERT( !test_bit(BITMAP_IO, &mdev->flags) ) in drbd_main.c
 FIXME going to queue 'set_n_write from StartingSync' but 'write from resync_finished' still pending?
and similar.

This can be observed with e.g. tight invalidate loops in test scripts,
and probably has no real-life implication.

Still, that race can be solved by first quiescen the device,
before starting a new resync or verify.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Changes to the role and disk state should be delayed or rejected
while we establish a connection.

This is necessary, since the peer will base its resync decision
on the UUIDs and the state we sent in the drbd_connect() function.

The most prominent example for this race is becoming primary after
sending state and UUIDs and before the state changes to C_WF_CONNECTION.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

Since drbd_bump_write_ordering() is called in the attaching
process while the disk state is D_ATTACHING, it was not
considering these three flags during attach.

A call to this function was missing form drbd_adm_disk_opts().

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

Commit d0ef827e (drbd: switch configuration interface from connector to
genetlink) introduced a regression by removing the ability to set all
bits in the out of sync bitmap and to suspend updates to the activity log
of a disconnected device via the invalidate-remote management call.

Credits for reporting the issue are going to Arne Redlich.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

This is necessary in order to prepare the move of the (receiver side)
epoch list from the device (mdev) to the connection (tconn) objects.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>