For a long time, the receiving side has spread "too large" incoming
requests over multiple bios.  No need to shrink our max_bio_size
(max_hw_sectors) if the peer is reconfigured to use a different storage.

The problem manifests itself if we are not the top of the device stack
(DRBD is used a LVM PV).

A hardware reconfiguration on the peer may cause the supported
max_bio_size to shrink, and the connection handshake would now
unnecessarily shrink the max_bio_size on the active node.

There is no way to notify upper layers that they have to "re-stack"
their limits. So they won't notice at all, and may keep submitting bios
that are suddenly considered "too large for device".

We already check for compatibility and ignore changes on the peer,
the code only was masked out unless we have a fully established connection.
We just need to allow it a bit earlier during the handshake.

Also consider max_hw_sectors in our merge bvec function, just in case.
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>

Symptoms: disconnect after bitmap exchange due to
bitmap overflow (e:49731075554) while decoding bm RLE packet

In the decoding step of the variable length integer run length encoding
there was potentially an uncatched bitshift by wordsize (variable >> 64).

The result of which is "undefined" :(
(only "sometimes" the result is the desired 0)

Fix: don't do any bit shift magic for shift == 64, just assign.
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>

Online adding of new minors with freshly created meta data
to an resource with an established connection failed, with a
wrong state transition on one side on one side of the new minor.

Freshly created meta-data has a la_size (last agreed size) of 0.
When we online add such devices, the code wrongly got into
the code path for resyncing new storage that was added while
the disk was detached.

Fixed that by making the GREW from ZERO a special case.
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>

Since drbd-8.4.0 it is possible to change the allow-two-primaries
network option while the connection is established.

The sequence code used to partially order packets from the
data socket with packets from the meta-data socket, still assued
that the allow-two-primaries option is constant while the
connection is established.

I.e.
On a node that has the RESOLVE_CONFLICTS bits set, after enabling
allow-two-primaries, when receiving the next data packet it timed out
while waiting for the necessary packets on the data socket to arrive
(wait_for_and_update_peer_seq() function).

Fixed that by always tracking the sequence number, but only waiting
for it if allow-two-primaries is set.
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>

If we want to iterate over the (as of yet still empty) list in the
cleanup path, we need to initialize the list before the first goto fail.
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>

Don't emit OOM warnings when k.alloc calls fail when
there there is a v.alloc immediately afterwards.

Converted a kmalloc/vmalloc with memset to kzalloc/vzalloc.
Signed-off-by: NJoe Perches <joe@perches.com>
Acked-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Allow to change the AL layout with an resize operation. For that
the reisze command gets two new fields: al_stripes and al_stripe_size.

In order to make the operation crash save:
1) Lock out all IO and MD-IO
2) Write the super block with MDF_PRIMARY_IND clear
3) write the bitmap to the new location (all zeros, since
   we allow only while connected)
4) Initialize the new AL-area
5) Write the super block with the restored MDF_PRIMARY_IND.
6) Unfreeze all IO

Since the AL-layout has no influence on the protocol, this operation
needs to be beforemed on both sides of a resource (if intended).
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>

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>

Fix to return a negative error code from the error handling
case instead of 0, as returned elsewhere in this function.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
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: NJens Axboe <axboe@kernel.dk>

The value passed is 0 in all but "it can never happen" cases (and those
only in a couple of drivers) *and* it would've been lost on the way
out anyway, even if something tried to pass something meaningful.
Just don't bother.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Use preferable function name which implies using a pseudo-random
number generator.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The only part of proc_dir_entry the code outside of fs/proc
really cares about is PDE(inode)->data.  Provide a helper
for that; static inline for now, eventually will be moved
to fs/proc, along with the knowledge of struct proc_dir_entry
layout.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Recently introduced al_begin_io_nonblock() was returning -EBUSY,
even when it should return -EWOULDBLOCK.

Impact:
A few spurious wake_up() calls in prepare_al_transaction_nonblock().
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>

It was unnoticed for some time that assigning to current->policy is
no longer sufficient to set a real time priority for a kernel thread.
Reported-by: NCharlie Suffin <Charlie.Suffin@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 <axboe@kernel.dk>

With an automatic after split-brain recovery policy of
"after-sb-1pri call-pri-lost-after-sb",
when trying to drbd_set_role() to R_SECONDARY,
we run into a deadlock.

This was first recognized and supposedly fixed by
2009-06-10 "Fixed a deadlock when using automatic split brain recovery when both nodes are"
replacing drbd_set_role() with drbd_change_state() in that code-path,
but the first hunk of that patch forgets to remove the drbd_set_role().

We apparently only ever tested the "two primaries" case.
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>

If single_open() fails in drbd_proc_open(), module refcount is left incremented.
The patch adds module_put() on the error path.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
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 sanity check when receiving P_BARRIER_ACK does expect all write
requests with a given req->epoch to have been either all replicated,
or all not replicated.

Because req->epoch was assigned before calling maybe_pull_ahead(),
this expectation was not met, leading to an off-by-one in the sanity
check, and further to a "Protocol Error".

Fix: move the call to maybe_pull_ahead() a few lines up,
and assign req->epoch only after that.
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 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>

We forgot to free the disk_conf,
so for each attach/detach cycle we leaked 336 bytes.
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 completed empty flushes (blkdev_issue_flush()) with IO error
if we lost the local disk, even if we still have an established
replication link to a healthy remote disk.

Fix this to only report errors to upper layers,
if neither local nor remote data is reachable.
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>

Introduced in drbd: always write bitmap on detach,
the bitmap bulk writeout on detach was indicating
it expected exclusive bitmap access.

Where I meant to say: expect no more modifications,
but testing/counting is still allowed.
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>

Since commit
  drbd: Disallow the peer_disk_state to be D_OUTDATED while connected
trying to invalidate a disconnected Primary returned an error code
that did not really match the situation:
"Refusing to be Outdated while Connected"

Insert two more specific conditions into is_valid_state(),
changing that to "Need access to UpToDate data",
respectively "Need a connection to start verify or resync".
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>

We've seen a spurious full resync, because a connection breakage
raced with drbd_start_resync(, C_SYNC_TARGET),
and the resulting state change request intended to start the resync
ended up looking like a local invalidate.

Fix:
Double check the state inside the lock,
and don't even request that state change,
if we had connection or IO problems.
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>

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>

There may have been more incoming requests while we where preparing
the current transaction. Try to consolidate more updates into this
transaction until we make no more progres.
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 IO accounting of the drbd "queue depth" was misleading.
We only started IO accounting once we already wrote the activity log.
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>

Depending on current IO depth, try to consolidate as many updates
as possible into one activity log transaction.
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>

To make the code easier to follow,
use an explicit find_active_resync_extent(),
and add a "nonblock" parameter to _al_get().
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>

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 is in preparation to be able to defer requests that need to wait
for an activity log transaction to a submitter workqueue.
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>