LU-12080 lnet: recovery event handling broken
    
Don't increment health on unlink event.
If a SEND fails an unlink will follow so no need to do any
special processing on SEND event. If SEND succeeds then we
wait for the reply.
When queuing a message on the NI recovery queue only do so
if the MT thread is still running.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I4877caebcac5cdfc35a59a18a3e3451b1f23cb0d

LU-12080 lnet: clean mt_eqh properly
    
There is a scenario where you have a peer on your recovery queue
that's down. So you keep pinging it, but every ping times out
after 10 seconds. In the middle of these 10 seconds you perform a
shutdown. First you try to do the rsp_tracker_clean. It goes through
and calls MDUnlink on the MD related to that ping. But because the
message has a ref count on the MD, it doesn't go away. The MD gets
zombied. And just waits for lnet_md_unlink to be called in
lnet_finalize(). Then you hit clean_peer_ni_recovery. We see the peer
on the queue, we try to call Unlink on it, but when we lookup the
MD using lnet_handle2md() we can't find it. Afterwards we try to clean
up the EQ and it asserts. Even if we remove the assert we end up with
a resource leak since the EQ is not actually freed since we won't call
LNetEQFree() again.
   
The solution is to pull the EQ create in the LNetNIInit() and deletion
happens in lnet_unprepare. By this point all the remaining messages
would've been finalized and all references on the EQ are gone,
allowing us to clean it up properly
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I7fd6018ee2e57f82c649fc3658352e89a4309986

LU-12344 lnet: handle remote health error
    
When a peer is dead set the health status to REMOTE_DROPPED
in order to handle health properly for the peer.
When dropping a routed message set REMOTE_ERROR. Routed messages
are dropped when the routing feature is turned off which could
be considered a configuration error if it happens in the middle
of traffic. Therefore, it's better to flag this issue at this
point without resending the message.
    
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I131263215a68fc8607582643a47007ce4d04abbc

LU-11816 lnet: setup health timeout defaults
    
Enable health feature by default.
Setup transaction timeout to a default 10 seconds and
retry count to 3 when health is enabled. When health
is disabled set default transaction timeout to 50.
When toggling between health enabled/disabled the defaults
will always kick in.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I153c2822898b44e33871ec827de7e61f153bb1db

LU-12163 lnet: fix cpt locking
    
In lnet_select_pathway() the call to lnet_handle_send_case_locked()
can result in sd_cpt being changed. If this function returns
REPEAT_SEND, we'll go back to the again label. It is possible at
this time to initiate discovery, which will unlock the cpt.
If the local cpt isn't updated we could potentially be manipulating
the wrong cpt resulting in some form of corruption or dead lock.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ifd39b0d84f8cce859151f7cc900a082481dd7218

LU-12201 lnet: detach response tracker
    
We need to unlink the response tracker from MDs even if the
corresponding message failed to send.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I4f320274576790e3332f66f30aad5c2b3450b955

LU-11297 lnet: invalidate recovery ping mdh
    
For cleanliness, ensure that recovery ping mdh is invalidated when
an peer ni or a local ni are allocated
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: If06448b1602b3680831244923b6b982a555159ea

LU-12249 lnet: fix list corruption
    
In shutdown the resend queues are cleared and freed. The monitor
thread state is set to shutdown. It is possible to get lnet_finalize()
called after the queues are freed. The code checks for ln_state to see
if we're shutting down. But in this case we should really be checking
ln_mt_state. The monitor thread is the one that matters in this case,
because it's the one which allocates and frees the resend queues.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ia077cec7a52ef5cd2e1b231437c6265ba9416b1b

LU-12254 lnet: correct discovery LNetEQFree()
    
The EQ needs to be freed after all the queues are cleaned to avoid
having non-processed events on the event queue on free. This will
prevent the memory from being freed.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ie38ec25e09bf6d7cf2aadc30edd91d298897c51b

LU-12264 lnet: Protect lp_dc_pendq manipulation with lp_lock
    
Protect the peer discovery queue from concurrent manipulation by
acquiring the lp_lock.
    
Test-Parameters: forbuildonly
Signed-off-by: Chris Horn <hornc@cray.com>
Change-Id: If43b877c1c7ea203f346a3d6ea846f00b8f9661f

LU-12199 lnet: Ensure md is detached when msg is not committed
    
It's possible for lnet_is_health_check() to return "true" when the
message has not hit the network. In this situation the message is
freed without detaching the MD. As a result, requests do not receive
their unlink events and these requests are stuck forever.
    
A little cleanup is included here:
 - The value of lnet_is_health_check() is only used in one place, so
   we don't need to save the result of it in a variable.
 - We don't need separate logic to detach the md when the send was
   successful. We'll fall through to the finalizing code after
   incrementing the health counters
    
Test-Parameters: forbuildonly
Cray-bug-id: LUS-7239
Signed-off-by: Chris Horn <hornc@cray.com>
Change-Id: I6301d491090b862d016eed3aac8afd7be8685e57

LU-12199 lnet: verify msg is commited for send/recv
    
Before performing a health check make sure the message
is committed for either send or receive. Otherwise we
can just finalize it.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Id7bd956f8e81e60a2d63059730973f851d4c7abe

LU-12339 lnet: select LO interface for sending
    
In the following scenario
    
Lustre->LNetPrimaryNID with 0@lo
Discover is initiated on 0@lo
The peer is created with 0@lo and <addr>@<net>
The interface health of the peer's <addr>@<net> is decremented
LNetPut() to self on <addr>@<net>
selection algorithm selects 0@lo to send to
    
This exposes an issue where we try and go through the peer credit
management algorithm, but because there are no credits associated with
0@lo we end up indefinitely queuing the message. ptlrpc will then get
stuck waiting for send completion on the message.
    
This was exposed via conf-sanity 32a
    
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I98e9d3428b594a0d041d27d8e8d8de7596825edc

LU-10153 lnet: remove route add restriction
    
Remove restriction with adding routes to the same remote network
via two different gateways.
    
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Iefc5aa10f73e9e7bdd283f5e933fbb8ee819df50

LU-11292 lnet: Discover routers on first use

Discover routers on first use. This brings the behavior when
interacting with routers inline with when dealing with normal
peers.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I8527e41daf2f5f6ab5f04aac1285aaa6cc4ee594

LU-11298 lnet: use peer for gateway

The routing code uses peer_ni for a gateway. However with Mulit-Rail
a gateway could have multiple interfaces on several different
networks. Instead of using a single peer_ni as the gateway we should
be using the peer and let the MR selection code select the best
peer_ni to send to.

This patch moves the gateway from peer to peer_ni. Much of the
code needs to be rewritten in the following patches to account
for that change. This patch disables the routing features by
disabling the code to add/delete routes.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ia7dab552268c4a7fbd7b88122b9a95363d155fd7

lnet_is_route_alive()
lnet_rtr_addref_locked()
lnet_rtr_decref_locked()
lnet_shuffle_seed()
lnet_add_route_to_rnet()
lnet_add_route() # the bulk of the code is removed
lnet_check_routes() # the bulk of the code is removed
lnet_del_route() # the bulk of the code is removed
lnet_parse_rc_info() # the bulk of the code is removed
lnet_destroy_rc_data()
lnet_update_rc_data_locked()
lnet_router_check_interval()
lnet_ping_router_locked()
lnet_prune_rc_data()
lnet_compare_peers()

lpni_rtrq # moved
lpni_rtr_list # moved
lpni_ping_notsent # deleted
lpni_ping_timestamp # deleted
lpni_ping_deadline # deleted
lpni_rtr_refcount # moved
lpni_healthy # this is a remnant code which is cleaned up
lpni_routes # moved

struct lnet_peer *lr_gateway # this is now lnet_peer instead of lnet_peer_ni
__u32 lr_lnet

LU-11299 lnet: lnet_add/del_route()

Reimplemented lnet_add_route() and lnet_del_route() to use
the peer instead of the peer_ni.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I3734098a81ab18d1d74220c691d96a9b9817e6da

lnet_rtr_addref_locked()
lnet_rtr_decref_locked()
lnet_shuffle_seed()
lnet_add_route_to_rnet()
lnet_add_route()
lnet_del_route_from_rnet()
lnet_del_route()

LU-11551 lnet: Do not allow deleting of router nis
    
Check the peer before deleting a peer_ni. If it's a router then do
not allow deletion of the peer-ni.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I372052b4e9b5af3a8f18a49676fc60b4c8077cbd

LU-11300 lnet: router sensitivity
    
Introduce the lnet_router_sensitivity module parameter to control
the sensitivity of routers to failures. It defaults to 100% which
means a router interface needs to be fully healthy in order to be
used.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I3e9333033f049918c1cdca58a72604c71884acbe

LU-11300 lnet: configure lnet_router_sensitivity
    
Allow the configuration of lnet_router_sensitivity from the user space utility lnetctl
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I715059580d3d2d443432a8b550d4cdafc9f9f632

LU-11300 lnet: cache ni status

When processing the data in the PUSH or the REPLY make sure to cache
the ns_status. This is the status of the peer_ni as reported by the
peer itself.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I14de2460f578fb7f47d329a97b8833f49c569b74

LU-11300 lnet: Cache the routing feature
    
When processing a REPLY or a PUSH for a discovery cache the
whether the routing feature is enabled or disabled as
reported by the peer.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I69bd41fade196773af0e1004c2e7fff2fb91392d

LU-11300 lnet: peer aliveness

Peer NI aliveness is now solely dependent on the health
infrastructure. With the addition of router_sensitivity_percentage,
peer NI is considered dead if its health drops below the percentage
specified of the total health. Setting the percentage to 100% means
that a peer_ni is considered dead if it's interface is less than
fully healthy.

Removed obsolete code that queries the peer NI every second since
the health infrastructure introduces the recovery mechanism which
is designed to recover the health of peer NIs.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I506060fbb66c74295808891b689d7d634dc69284

LU-11300 lnet: router aliveness

A route is considered alive if the gateway is able to route
messages from the local to the remote net. That means that
at least one of the network interfaces on the remote net of
the gateway is viable.

Introduced the concept of sensitivity percentage. This defaults
to 100%. It holds a dual meaning:
1. A route is considered alive if at least one of the its interfaces'
health is >= LNET_MAX_HEALTH_VALUE * router_sensitivity_percentage
100 means at least one interface has to be 100% healthy
2. On a router consider a peer_ni dead if its health is not at least
LNET_MAX_HEALTH_VALUE * router_sensitivity_percentage.
100% means the interface has to be 100% healthy.

Re-implemented lnet_notify() to decrement the health of the
peer interface if the LND reports a failure on that peer.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ie97561fb70bf6a558bc90fa9266a6ba38fa3d293

LU-11300 lnet: simplify lnet_handle_local_failure()
    
Pass the struct lnet_ni to lnet_handle_local_failure() instead of the
message structure, since nothing else from the message is being
used. This also makes symmetrical with lnet_handle_remote_failure()
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I10146ec5bf5f378e28a7725382f00132ada32c6e

LU-11299 lnet: Cleanup rcd
    
Cleanup all code pertaining to rcd, as routing code will use
discovery going forward and there will be no need to keep its own
pinging code.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: If31caa3b5703df40b6ae0f758f2fe764991aa4f3

LU-11299 lnet: modify lnd notification mechanism
    
LND notifies when a peer is up or down. If a it notifies
LNet that the peer is up and sets the "reset" flag to true
then this indicates to LNet that the LND knows about the health
of the peer and is telling LNet that the peer is fully healthy.
LNet will set the health value of the peer to maximum, otherwise
it will increment the health by one.
    
If the LND notifies the LNet that the peer is down, LNet will
decrement the health of the peer by sensitivity value configured.
    
LNet then turns around and rechecks the peer aliveness and if its
dead it'll notify the LND. This code is only used by the socklnd
because it needs to teardown connections. This is in keeping with
the original funcionality.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ifa614405fb0c2cd4f6bcb1a2a97e856320eb6cbe

LU-11299 lnet: use discovery for routing

Instead re-inventing the wheel, routing now uses discovery.
Everyone router interval the router is discovered. This will
update the router information locally and will serve to let the 
router know that the peer is alive.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I211bf15af0b0a5d50f9e2a69a385419a1dd5096

LU-11378 lnet: MR aware gateway selection

When selecting a route use the Multi-Rail Selection algorithm to
select the best available peer_ni of the best route. The selected
peer_ni can then be used to send the message or to discover it
if the gateway peer needs discovering.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I376af57611591eed2eb1edb80a1b3a68b5aefd19

LU-11300 lnet: consider router_check_interval

Consider router_check_interval when waking up the monitor thread,
to make sure you wakeup the monitor thread at the earliest possible
time.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ibc4b53886b59a9bc174a29d0da711ac77db3a62c

LU-11475 lnet: allow deleting router primary_nid

Discovery doesn't allow deleting a primary_nid of a peer. This
is necessary because upper layers only know to reach the peer by
using the primary_nid. For routers this is not the case. So
if a router changes its interfaces and comes back up again, the
peer_ni should be adjusted.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I9da056172f35a5f15eed5ba0e02fcb37ac414c54

LU-11475 lnet: transfer routers
    
When a primary NID of a peer is about to be deleted because
it's being transfered to another peer, if that peer is a gateway
then transfer all gateway properties to the new peer.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ib475c389ca5630906416a5112b3088f6f5d03950

LU-11477 lnet: handle health for incoming messages

In case of routers (as well as for the general case) it's important to
update the health of the ni/lpni for incoming messages. For an lpni
specifically when we receive a message is when we know that the lpni
is up.

A percentage router health is required in order to send a message to a
gateway. That defaults to 100, meaning that a router interface has to
be absolutely healthy in order to send to it. This matches the current
behavior. So if a router interface goes down an its health goes down
significantly, but then it comes back up again; either we receive a
message from it or we discover it and get a reply, then in order to
start using that router interface again we have to boost its health
all the way up to maximum.

This behavior is special cased for routers.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ida6c23f95dbef56c2e6ed7b6d03743939d8b30a0

LU-11478 lnet: misleading discovery seqno.

There is a sequence number used when sending discovery messages. This
sequence number is intended to detect stale messages. However it
could be misleading if the peer reboots. In this case the peer's
sequence number will reset. The node will think that all information
being sent to it is stale, while in reality the peer might've
changed configuration.

There is no reliable why to know whether a peer rebooted, so we'll
always assume that the messages we're receiving are valid. So we'll
operate on first come first serve basis.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I421a00e47bc93ee60fa37c648d6d9a726d9def9c

LU-11470 lnet: drop all rule

Add a rule to drop all messages arriving on a specific interface.
This is useful for simulating failures on a specific router interface.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ic69f683fb2caf7a69a1d85428878c89b7b1ee3ad

LU-11641 lnet: handle discovery off

When discovery is turned off locally or when the peer either has
discovery off or doesn't support MR at all then degrade discovery
behavior to a standard ping. This will allow routers to continue
using discovery mechanism even if it's turned off.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I7f0829d37cbff2bf9e41de251efa715fc4c97e5d

LU-11297 lnet: handle router health off

Routing infrastructure depends on health infrastructure to manage
route status. However, health can be turned off. Therefore, we need
to enable health for gateways in order to monitor them properly.
Each peer now has its own health sensitivity. When adding a route
the gateway's health sensitivity can be explicitly set from lnetctl
or if not specified then it'll default to 1, thereby turning health
on for that gateway, allowing peer NI recovery if there is a failure.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ibae33d595e97d0eec432ae8f5d51898ce0776f01

LU-11297 lnet: set gw sensitivity from lnetctl

Allow an optional parameter from the:
lnetctl route add
command to set the health sensitivity of the gateway
lnetctl route add --net <net> --gateway <gw> --sensitivity <value>

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Iee120c78a41b79da6ab6bdf1560f558df89233e2

LU-11664 lnet: push router interface updates

A router can bring up/down its interfaces if it hasn't received any
messages on that interface for a configurable period
(alive_router_ping_timeout). When this even occures the router can now
push its status change to the peers it's talking to in order to inform
them of the change in its status. This will allow the router users to
handle asym router failures quicker.

Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I9530ed7d9bc0a86edc43e3f610cc943f1732dcfd

LU-11299 lnet: net aliveness
    
If a router is discovered on any interface on the network, then
update the network last alive time and the NI's status to UP.
If a router isn't discovered on any interface on a network,
then change the status of all the interfaces on that network to down.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I1d67eb4b3284ccb8306ad4c877a2fcbdf4958d8c

LU-11299 lnet: discover each gateway Net
    
Wakeup every gateway aliveness interval / number of local networks.
Discover each local gateway network in round robin.
    
This is done to make sure the gateway keeps its networks up.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehat <ashehata@whamcloud.com>
Change-Id: I4035e39c286cb599d4eb8f9df7ed5d278e6d744a

LU-12053 lnet: look up MR peers routes
    
An MR peer can have multiple interfaces some of which we might
have a route to. The primary NID of the peer might not necessarily
specify a NID we have a route to. When looking up a route, we must
iterate over all the nets the peer is on and select the one which
we can route to. Taking into consideration the peer can exist on
multiple routed networks we also have a simple round robin algorithm
to iterate over all the networks we can reach the peer on.
    
Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I0651dd4f732c8b71872f73cf2512b08f34129bd9

LU-12200 lnet: check peer timeout on a router
    
On a router assume that a peer is alive and attempt to send it
messages as long as the peer_timeout hasn't expired.
    
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I0806a52c8ad7acc1c93dcf32353f1c4467c618b1