Since moving to memalloc_nofs_save/restore, SUNRPC has stopped setting the
GFP_NOIO flag on sk_allocation which the networking system uses to decide
when it is safe to use current->task_frag. The results of this are
unexpected corruption in task_frag when SUNRPC is involved in memory
reclaim.
The corruption can be seen in crashes, but the root cause is often
difficult to ascertain as a crashing machine's stack trace will have no
evidence of being near NFS or SUNRPC code. I believe this problem to
be much more pervasive than reports to the community may indicate.
Fix this by having kernel users of sockets that may corrupt task_frag due
to reclaim set sk_use_task_frag = false. Preemptively correcting this
situation for users that still set sk_allocation allows them to convert to
memalloc_nofs_save/restore without the same unexpected corruptions that are
sure to follow, unlikely to show up in testing, and difficult to bisect.
CC: Philipp Reisner <philipp.reisner@linbit.com>
CC: Lars Ellenberg <lars.ellenberg@linbit.com>
CC: "Christoph Böhmwalder" <christoph.boehmwalder@linbit.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Josef Bacik <josef@toxicpanda.com>
CC: Keith Busch <kbusch@kernel.org>
CC: Christoph Hellwig <hch@lst.de>
CC: Sagi Grimberg <sagi@grimberg.me>
CC: Lee Duncan <lduncan@suse.com>
CC: Chris Leech <cleech@redhat.com>
CC: Mike Christie <michael.christie@oracle.com>
CC: "James E.J. Bottomley" <jejb@linux.ibm.com>
CC: "Martin K. Petersen" <martin.petersen@oracle.com>
CC: Valentina Manea <valentina.manea.m@gmail.com>
CC: Shuah Khan <shuah@kernel.org>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: David Howells <dhowells@redhat.com>
CC: Marc Dionne <marc.dionne@auristor.com>
CC: Steve French <sfrench@samba.org>
CC: Christine Caulfield <ccaulfie@redhat.com>
CC: David Teigland <teigland@redhat.com>
CC: Mark Fasheh <mark@fasheh.com>
CC: Joel Becker <jlbec@evilplan.org>
CC: Joseph Qi <joseph.qi@linux.alibaba.com>
CC: Eric Van Hensbergen <ericvh@gmail.com>
CC: Latchesar Ionkov <lucho@ionkov.net>
CC: Dominique Martinet <asmadeus@codewreck.org>
CC: Ilya Dryomov <idryomov@gmail.com>
CC: Xiubo Li <xiubli@redhat.com>
CC: Chuck Lever <chuck.lever@oracle.com>
CC: Jeff Layton <jlayton@kernel.org>
CC: Trond Myklebust <trond.myklebust@hammerspace.com>
CC: Anna Schumaker <anna@kernel.org>
CC: Steffen Klassert <steffen.klassert@secunet.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
Suggested-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch uses assert_spin_locked() instead of lockdep_is_held()
where it's available to use because lockdep_is_held() is only available
if CONFIG_LOCKDEP is set.
In other cases like lockdep_sock_is_held() we surround it by a
CONFIG_LOCKDEP idef.
Fixes: dbb751ffab ("fs: dlm: parallelize lowcomms socket handling")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch is rework of lowcomms handling, the main goal was here to
handle recvmsg() and sendpage() to run parallel. Parallel in two senses:
1. per connection and 2. that recvmsg()/sendpage() doesn't block each
other.
Currently recvmsg()/sendpage() cannot run parallel because two
workqueues "dlm_recv" and "dlm_send" are ordered workqueues. That means
only one work item can be executed. The amount of queue items will be
increased about the amount of nodes being inside the cluster. The current
two workqueues for sending and receiving can also block each other if the
same connection is executed at the same time in dlm_recv and dlm_send
workqueue because a per connection mutex for the socket handling.
To make it more parallel we introduce one "dlm_io" workqueue which is
not an ordered workqueue, the amount of workers are not limited. Due
per connection flags SEND/RECV pending we schedule workers ordered per
connection and per send and receive task. To get rid of the mutex
blocking same workers to do socket handling we switched to a semaphore
which handles socket operations as read lock and sock releases as write
operations, to prevent sock_release() being called while the socket is
being used.
There might be more optimization removing the semaphore and replacing it
with other synchronization mechanism, however due other circumstances
e.g. othercon behaviour it seems complicated to doing this change. I
added comments to remove the othercon handling and moving to a different
synchronization mechanism as this is done. We need to do that to the next
dlm major version upgrade because it is not backwards compatible with the
current connect mechanism.
The processing of dlm messages need to be still handled by a ordered
workqueue. An dlm_process ordered workqueue was introduced which gets
filled by the receive worker. This is probably the next bottleneck of
DLM but the application can't currently parse dlm messages parallel. A
comment was introduced to lift the workqueue context of dlm processing
in a non-sleepable softirq to get messages processing done fast.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removes a init of an error value to -EINVAL which is not
necessary.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch changes the handling of calling the original
sk_error_report() by not putting it on the stack and calling it later.
If the listen_sock.sk_error_report() is NULL in this moment it indicates
a bug in our implementation.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removes null checks on private data for sockets. If we have a
null dereference there we having a bug in our implementation that such
callback occurs in this state.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch merges the dlm_node_addrs lookup list to the connection
structure. It is a per node mapping to some configuration setup by
configfs. We don't need two lookup structures. The connection hash has
now a lifetime like the dlm_node_addrs entries. Means we add only new
entries when configure cluster and not while new connections are coming
in, remove connection when a node got fenced and cleanup all connection
when the dlm exits. It should work the same and even will show more
issues because we don't try to somehow keep those two data structures in
sync with the current cluster configuration.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removes to allocate the dlm_local_addr[] pointers on the
heap. Instead we directly store the type of "struct sockaddr_storage".
This removes function deinit_local() because it was freeing memory only.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removes save_listen_callbacks() and add_listen_sock() as they
are only used once in lowcomms functionality. For shutdown lowcomms it's
not necessary to whole flush the workqueues to synchronize with
restoring the old sk_data_ready() callback. Only the listen con receive
work need to be cancelled. For each individual node shutdown we should be
sure that last ack was been transmitted which is done by flushing per
connection swork worker.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Since commit 489d8e559c ("fs: dlm: add reliable connection if
reconnect") we have functionality like TCP offers for half-closed
sockets on dlm application protocol layer. This feature is required
because the cluster manager events about leaving resource memberships
can be locally already occurred but other cluster nodes having a pending
leaving membership over the cluster manager protocol happening. In this
time the local dlm node already shutdown it's connection and don't
transmit anymore any new dlm messages, but however it still needs to be
able to accept dlm messages because the pending leave membership request
of the cluster manager protocol which the dlm kernel implementation has
no control about it.
We have this functionality on the application for two reasons, the main
reason is that SCTP does not support such functionality on socket
layer. But we can do it inside application layer.
Another small issue is that this feature is broken in the TCP world
because some NAT devices does not implement such functionality
correctly. This is the same reason why the reliable connection session
layer in DLM exists. We give up on middle devices in the networking
which sends e.g. TCP resets out. In DLM we cannot have any message
dropping and we ensure it over a session layer that it can't happen.
Back to the half-closed grace shutdown handling. It's not necessary
anymore to do it on socket layer (which is only support for TCP sockets)
because we do it on application layer. This patch removes this handling,
if there are still issues then we have a problem on the application
layer for such handling.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch will switch from dlm_allow_conn to check if dlm lowcomms is
running or not to if we actually have a listen socket set or not. The
list socket will be set and unset in lowcomms start and shutdown
functionality. To synchronize with data_ready() callback we will set the
socket callback to NULL while socket lock is held.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Instead of check on list_empty() we can do the same with
list_first_entry_or_null() and return NULL if the returned value is NULL.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removed a twice INIT_WORK() functionality. We already doing
this inside of dlm_lowcomms_init() functionality which is called only
once dlm is loaded.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch introduces leftovers of init, start, stop and exit
functionality. The dlm application layer should always call the midcomms
layer which getting aware of such event and redirect it to the lowcomms
layer. Some functionality which is currently handled inside the start
functionality of midcomms and lowcomms should be handled in the init
functionality as it only need to be initialized once when dlm is loaded.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch drops additionally the sock_mutex when there is a sending
message burst. Since we have acknowledge handling we free sending
buffers only when we receive an ack back, but if we are stuck in
send_to_sock() looping because dlm sends a lot of messages and we never
leave the loop the sending buffer fill up very quickly. We can't receive
during this iteration because the sock_mutex is held. This patch will
unlock the sock_mutex so it should be possible to receive messages when
a burst of sending messages happens. This will allow to free up memory
because acks which are already received can be processed.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch fixes a race if we get two times an socket data ready event
while the listen connection worker is queued. Currently it will be
served only once but we need to do it (in this case twice) until we hit
-EAGAIN which tells us there is no pending accept going on.
This patch wraps an do while loop until we receive a return value which
is different than 0 as it was done before commit d11ccd451b ("fs: dlm:
listen socket out of connection hash").
Cc: stable@vger.kernel.org
Fixes: d11ccd451b ("fs: dlm: listen socket out of connection hash")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch fixes a double sock_release() call when the listen() is
called for the dlm lowcomms listen socket. The caller of
dlm_listen_for_all should never care about releasing the socket if
dlm_listen_for_all() fails, it's done now only once if listen() fails.
Cc: stable@vger.kernel.org
Fixes: 2dc6b1158c ("fs: dlm: introduce generic listen")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch fixes some grammar output in lowcomms implementation by
removing the "successful" word which should be "successfully" but it
can never be unsuccessfully so we remove it.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch will adds #ifndef __CHECKER__ for false positives warnings
about an imbalance lock/unlock srcu handling. Which are shown by running
sparse checks:
fs/dlm/midcomms.c:1065:20: warning: context imbalance in 'dlm_midcomms_get_mhandle' - wrong count at exit
Using __CHECKER__ will tell sparse to ignore these sections.
Those imbalances are false positive because from upper layer it is
always required to call a function in sequence, e.g. if
dlm_midcomms_get_mhandle() is successful there must be a
dlm_midcomms_commit_mhandle() call afterwards.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
The "sock" variable is not initialized on this error path.
Cc: stable@vger.kernel.org
Fixes: 2dc6b1158c ("fs: dlm: introduce generic listen")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch prints the cluster node address if a non-cluster node
(according to the dlm config setting) tries to connect. The current
hexdump call will print in a different loglevel and only available if
dynamic debug is enabled. Additional we using the ip address format
strings to print an IETF ip4/6 string represenation.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch introduces a kmem cache for dlm_msg handles which are used
always if dlm sends a message out. Even if their are covered by midcomms
layer or not.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch introduces a kmem cache for writequeue entry. A writequeue
entry get quite a lot allocated if dlm transmit messages.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch cleanups the code for allocating a new buffer in the dlm
writequeue mechanism. There was a possible tuneup to allow scheduling
while a new writequeue entry needs to be allocated because either no
sending page is available or are full. To avoid multiple concurrent
users checking at the same time if an entry is available or full
alloc_wq was introduce that those are waiting if there is currently a
new writequeue entry in process to be queued so possible further users
will check on the new allocated writequeue entry if it's full.
To simplify the code we just remove this mutex and switch that the
already introduced spin lock will be held during writequeue check,
allocation and queueing. So other users can never check on available
writequeues while there is a new one in process but not queued yet.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Currently we don't care if the DLM application stack is filling buffers
(not committed yet) while we transmit some already committed buffers.
By checking on active writequeue users before dequeue a writequeue entry
we know there is coming more data and do nothing. We wait until the send
worker will be triggered again if the writequeue entry users hit zero.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch will surround the AF_INET6 case in sk_error_report() of dlm
with a #if IS_ENABLED(CONFIG_IPV6). The field sk->sk_v6_daddr is not
defined when CONFIG_IPV6 is disabled. If CONFIG_IPV6 is disabled, the
socket creation with AF_INET6 should already fail because a runtime
check if AF_INET6 is registered. However if there is the possibility
that AF_INET6 is set as sk_family the sk_error_report() callback will
print then an invalid family type error.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 4c3d90570b ("fs: dlm: don't call kernel_getpeername() in error_report()")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch will replace the use of socket sk_callback_lock lock and uses
socket lock instead. Some users like sunrpc, see commit ea9afca88b
("SUNRPC: Replace use of socket sk_callback_lock with sock_lock") moving
from sk_callback_lock to sock_lock which seems to be held when the socket
callbacks are called.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
In some cases kernel_getpeername() will held the socket lock which is
already held when the socket layer calls error_report() callback. Since
commit 9dfc685e02 ("inet: remove races in inet{6}_getname()") this
problem becomes more likely because the socket lock will be held always.
You will see something like:
bob9-u5 login: [ 562.316860] BUG: spinlock recursion on CPU#7, swapper/7/0
[ 562.318562] lock: 0xffff8f2284720088, .magic: dead4ead, .owner: swapper/7/0, .owner_cpu: 7
[ 562.319522] CPU: 7 PID: 0 Comm: swapper/7 Not tainted 5.15.0+ #135
[ 562.320346] Hardware name: Red Hat KVM/RHEL-AV, BIOS 1.13.0-2.module+el8.3.0+7353+9de0a3cc 04/01/2014
[ 562.321277] Call Trace:
[ 562.321529] <IRQ>
[ 562.321734] dump_stack_lvl+0x33/0x42
[ 562.322282] do_raw_spin_lock+0x8b/0xc0
[ 562.322674] lock_sock_nested+0x1e/0x50
[ 562.323057] inet_getname+0x39/0x110
[ 562.323425] ? sock_def_readable+0x80/0x80
[ 562.323838] lowcomms_error_report+0x63/0x260 [dlm]
[ 562.324338] ? wait_for_completion_interruptible_timeout+0xd2/0x120
[ 562.324949] ? lock_timer_base+0x67/0x80
[ 562.325330] ? do_raw_spin_unlock+0x49/0xc0
[ 562.325735] ? _raw_spin_unlock_irqrestore+0x1e/0x40
[ 562.326218] ? del_timer+0x54/0x80
[ 562.326549] sk_error_report+0x12/0x70
[ 562.326919] tcp_validate_incoming+0x3c8/0x530
[ 562.327347] ? kvm_clock_read+0x14/0x30
[ 562.327718] ? ktime_get+0x3b/0xa0
[ 562.328055] tcp_rcv_established+0x121/0x660
[ 562.328466] tcp_v4_do_rcv+0x132/0x260
[ 562.328835] tcp_v4_rcv+0xcea/0xe20
[ 562.329173] ip_protocol_deliver_rcu+0x35/0x1f0
[ 562.329615] ip_local_deliver_finish+0x54/0x60
[ 562.330050] ip_local_deliver+0xf7/0x110
[ 562.330431] ? inet_rtm_getroute+0x211/0x840
[ 562.330848] ? ip_protocol_deliver_rcu+0x1f0/0x1f0
[ 562.331310] ip_rcv+0xe1/0xf0
[ 562.331603] ? ip_local_deliver+0x110/0x110
[ 562.332011] __netif_receive_skb_core+0x46a/0x1040
[ 562.332476] ? inet_gro_receive+0x263/0x2e0
[ 562.332885] __netif_receive_skb_list_core+0x13b/0x2c0
[ 562.333383] netif_receive_skb_list_internal+0x1c8/0x2f0
[ 562.333896] ? update_load_avg+0x7e/0x5e0
[ 562.334285] gro_normal_list.part.149+0x19/0x40
[ 562.334722] napi_complete_done+0x67/0x160
[ 562.335134] virtnet_poll+0x2ad/0x408 [virtio_net]
[ 562.335644] __napi_poll+0x28/0x140
[ 562.336012] net_rx_action+0x23d/0x300
[ 562.336414] __do_softirq+0xf2/0x2ea
[ 562.336803] irq_exit_rcu+0xc1/0xf0
[ 562.337173] common_interrupt+0xb9/0xd0
It is and was always forbidden to call kernel_getpeername() in context
of error_report(). To get rid of the problem we access the destination
address for the peer over the socket structure. While on it we fix to
print out the destination port of the inet socket.
Fixes: 1a31833d08 ("DLM: Replace nodeid_to_addr with kernel_getpeername")
Reported-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removes a list_first_entry() call which is already done by
the previous con_next_wq() call.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch changes the dlm_lowcomms_new_msg() function pointer private data
from "struct mhandle *" to "void *" to provide different structures than
just "struct mhandle".
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch adds tracepoints for dlm socket receive and send
functionality. We can use it to track how much data was send or received
to or from a specific nodeid.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Since commit 764ff4011424 ("fs: dlm: auto load sctp module") we try
load the sctp module before we try to create a sctp kernel socket. That
a socket creation fails now has more likely other reasons. This patch
removes the part of error to load the sctp module and instead printout
the error code.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch changes that we don't ack each message. Lowcomms will take
care about to send an ack back after a bulk of messages was processed.
Currently it's only when the whole receive buffer was processed, there
might better positions to send an ack back but only the lowcomms
implementation know when there are more data to receive. This patch has
also disadvantages that we might retransmit more on errors, however this
is a very rare case.
Tested with make_panic on gfs2 with three nodes by running:
trace-cmd record -p function -l 'dlm_send_ack' sleep 100
and
trace-cmd report | wc -l
Before patch:
- 20548
- 21376
- 21398
After patch:
- 18338
- 20679
- 19949
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch moves the kernel_recvmsg() loop call into the
receive_from_sock() function instead of doing the loop outside the
function and abort the loop over it's return value.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch will add a mutex that a connection can allocate a writequeue
entry buffer only at a sleepable context at one time. If multiple caller
waits at the writequeue spinlock and the spinlock gets release it could
be that multiple new writequeue page buffers were allocated instead of
allocate one writequeue page buffer and other waiters will use remaining
buffer of it. It will only be the case for sleepable context which is
the common case. In non-sleepable contexts like retransmission we just
don't care about such behaviour.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch adds a generic connect function for TCP and SCTP. If the
connect functionality differs from each other additional callbacks in
dlm_proto_ops were added. The sockopts callback handling will guarantee
that sockets created by connect() will use the same options as sockets
created by accept().
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch adds a "for now" better handling of missing SCTP support in
the kernel and try to load the sctp module if SCTP is set.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch combines each transport layer listen functionality into one
listen function. Per transport layer differences are provided by
additional callbacks in dlm_proto_ops.
This patch drops silently sock_set_keepalive() for listen tcp sockets
only. This socket option is not set at connecting sockets, I also don't
see the sense of set keepalive for sockets which are created by accept()
only.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch moves the per transport socket callbacks to a static const
array. We can support only one transport socket for the init namespace
which will be determinted by reading the dlm config at lowcomms_start().
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch introduce a function to determine if something is ready to
being send in the writequeue. It's not just that the writequeue is not
empty additional the first entry need to have a valid length field.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
If send_to_sock() sets CF_APP_LIMITED limited bit and it has not been
cleared by a waiting lowcomms_write_space() yet and a close_connection()
apprears we should clear the CF_APP_LIMITED bit again because the
connection starts from a new state again at reconnect.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Instead of dereference "con->sock" we can get the socket structure over
"sk->sk_socket" as well. This patch will switch to this behaviour.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch renames DEFAULT_BUFFER_SIZE to DLM_MAX_SOCKET_BUFSIZE and
LOWCOMMS_MAX_TX_BUFFER_LEN to DLM_MAX_APP_BUFSIZE as they are proper
names to define what's behind those values. The DLM_MAX_SOCKET_BUFSIZE
defines the maximum size of buffer which can be handled on socket layer,
the DLM_MAX_APP_BUFSIZE defines the maximum size of buffer which can be
handled by the DLM application layer.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Currently the dlm protocol values are that TCP is 0 and everything else
is SCTP. This makes it difficult to introduce possible other transport
layers. The only one user space tool dlm_controld, which I am aware of,
handles the protocol value 1 for SCTP. We change it now to handle SCTP
as 1, this will break user space API but it will fix it so we can add
possible other transport layers.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch checks if possible allowing new connections is allowed before
queueing the listen socket to accept new connections.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
The proper way to allocate ordered workqueues is to use
alloc_ordered_workqueue() function. The current way implies an ordered
workqueue which is also required by dlm.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch fixes the error path handling in lowcomms_start(). We need to
cleanup some static allocated data structure and cleanup possible
workqueue if these have started.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch will clean a dirty page buffer if a reconnect occurs. If a page
buffer was half transmitted we cannot start inside the middle of a dlm
message if a node connects again. I observed invalid length receptions
errors and was guessing that this behaviour occurs, after this patch I
never saw an invalid message length again. This patch might drops more
messages for dlm version 3.1 but 3.1 can't deal with half messages as
well, for 3.2 it might trigger more re-transmissions but will not leave dlm
in a broken state.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch introduce to make a tcp lowcomms connection reliable even if
reconnects occurs. This is done by an application layer re-transmission
handling and sequence numbers in dlm protocols. There are three new dlm
commands:
DLM_OPTS:
This will encapsulate an existing dlm message (and rcom message if they
don't have an own application side re-transmission handling). As optional
handling additional tlv's (type length fields) can be appended. This can
be for example a sequence number field. However because in DLM_OPTS the
lockspace field is unused and a sequence number is a mandatory field it
isn't made as a tlv and we put the sequence number inside the lockspace
id. The possibility to add optional options are still there for future
purposes.
DLM_ACK:
Just a dlm header to acknowledge the receive of a DLM_OPTS message to
it's sender.
DLM_FIN:
This provides a 4 way handshake for connection termination inclusive
support for half-closed connections. It's provided on application layer
because SCTP doesn't support half-closed sockets, the shutdown() call
can interrupted by e.g. TCP resets itself and a hard logic to implement
it because the othercon paradigm in lowcomms. The 4-way termination
handshake also solve problems to synchronize peer EOF arrival and that
the cluster manager removes the peer in the node membership handling of
DLM. In some cases messages can be still transmitted in this time and we
need to wait for the node membership event.
To provide a reliable connection the node will retransmit all
unacknowledges message to it's peer on reconnect. The receiver will then
filtering out the next received message and drop all messages which are
duplicates.
As RCOM_STATUS and RCOM_NAMES messages are the first messages which are
exchanged and they have they own re-transmission handling, there exists
logic that these messages must be first. If these messages arrives we
store the dlm version field. This handling is on DLM 3.1 and after this
patch 3.2 the same. A backwards compatibility handling has been added
which seems to work on tests without tcpkill, however it's not recommended
to use DLM 3.1 and 3.2 at the same time, because DLM 3.2 tries to fix long
term bugs in the DLM protocol.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
