glusterfs.git/rpc/rpc-lib/src/rpc-clnt.h, branch v3.7.20

changelog/rpc: Fix rpc_clnt_t mem leaks

2016-07-27T10:13:33+00:00

Backport of http://review.gluster.org/13658

PROBLEM:
   1. Freeing up rpc_clnt object might lead to crashes. Well,
      it was not a necessity to free rpc-clnt object till now
      because all the existing use cases needs to reconnect
      back on disconnects. Hence timer code was not taking
      ref on rpc-clnt object.

      Glusterd had some use-cases that led to crash due to
      ping-timer and they fixed only those code paths that
      involve ping-timer.

      Now, since changelog has an use-case where rpc-clnt
      need to be freed up, we need to fix timer code to take
      refs

   2. In changelog, because of issue 1, only mydata was being
      freed which is incorrect. And there are races where
      rpc-clnt object would access the freed mydata which
      would lead to crashes.

      Since changelog xlator resides on brick side and is long
      living process, if multiple libgfchangelog consumers
      register to changelog and disconnect/reconnect mulitple
      times, it would result in leak of 'rpc-clnt' object
      for every connect/disconnect.

SOLUTION:
   1. Handle ref/unref of 'rpc_clnt' structure in timer
      functions properly.
   2. In changelog, unref 'rpc_clnt' in RPC_CLNT_DISCONNECT
      after disabling timers and free mydata on RPC_CLNT_DESTROY.

RPC SETUP IN CHANGELOG:
   1. changelog xlator initiates rpc server say 'changelog_rpc_server'
   2. libgfchangelog initiates one rpc server say 'libgfchangelog_rpc_server'
   3. libgfchangelog initiates rpc client and connects to 'changelog_rpc_server'
   4. In return changelog_rpc_server initiates a rpc client and connects back
      to 'libgfchangelog_rpc_server'

REF/UNREF HANDLING IN TIMER FUNCTIONS:
Let's say rpc clnt refcount = 1
   1. Take the ref before reigstering callback to timer queue
           >>>>  rpc_clnt_ref (say ref count becomes = 2)
   2. Register a callback to timer say 'callback1'
   3. If register fails:
           >>>> rpc_clnt_unref (ref count = 1)
   4. On timer expiration, 'callback1' gets called. So unref rpc clnt at the end
      in 'callback1'. This is corresponding to ref taken in step 1
           >>>> rpc_clnt_unref (ref count = 1)
   5. The cycle from step-1 to step-4 continues....until timer cancel event happens
   6. timer cancel of say 'callback1'
           If timer cancel fails:
                 Do nothing, Step-4 would have unrefd
           If timer cancel succeeds:
                 >>>> rpc_clnt_unref (ref count = 1)

Change-Id: I91389bc511b8b1a17824941970ee8d2c29a74a09
BUG: 1359363
Signed-off-by: Kotresh HR 
(cherry picked from commit 637ce9e2e27e9f598a4a6c5a04cd339efaa62076)
Reviewed-on: http://review.gluster.org/14993
CentOS-regression: Gluster Build System 
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Raghavendra G

glusterd/rpc : Discard duplicate Disconnect events

2016-03-23T14:50:23+00:00

Backport of http://review.gluster.org/#/c/13790/

If a peer rpc disconnect event has been already processed, skip the furthers as
processing them are overheads and sometimes may lead to a crash like due to a
double free

Change-Id: Iec589ce85daf28fd5b267cb6fc82a4238e0e8adc
BUG: 1320374
Signed-off-by: Atin Mukherjee 
Reviewed-on: http://review.gluster.org/13790
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Jeff Darcy 
Reviewed-on: http://review.gluster.org/13813

rpc: add owner xlator argument to rpc_clnt_new

2015-08-14T10:10:47+00:00

The @owner argument tells RPC layer the xlator that owns
the connection and to which xlator THIS needs be set during
network notifications like CONNECT and DISCONNECT.

Code paths that originate from the head of a (volume) graph and use
STACK_WIND ensure that the RPC local endpoint has the right xlator saved
in the frame of the call (callback pair). This guarantees that the
callback is executed in the right xlator context.

The client handshake process which includes fetching of brick ports from
glusterd, setting lk-version on the brick for the session, don't have
the correct xlator set in their frames. The problem lies with RPC
notifications. It doesn't have the provision to set THIS with the xlator
that is registered with the corresponding RPC programs. e.g,
RPC_CLNT_CONNECT event received by protocol/client doesn't have THIS set
to its xlator. This implies, call(-callbacks) originating from this
thread don't have the right xlator set too.

The fix would be to save the xlator registered with the RPC connection
during rpc_clnt_new. e.g, protocol/client's xlator would be saved with
the RPC connection that it 'owns'. RPC notifications such as CONNECT,
DISCONNECT, etc inherit THIS from the RPC connection's xlator.

Change-Id: I9dea2c35378c511d800ef58f7fa2ea5552f2c409
BUG: 1253212
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/11436
Tested-by: Gluster Build System 
Tested-by: NetBSD Build System 
Reviewed-by: Raghavendra G 
(cherry picked from commit f7668938cd7745d024f3d2884e04cd744d0a69ab)
Reviewed-on: http://review.gluster.org/11908
Reviewed-by: Pranith Kumar Karampuri

client, rpc: make ping-timeout configurable for glusterfs clients

2015-08-13T05:05:57+00:00

Change-Id: Idd94adb0457aaffce7330f56f98cebafa2c4dae8
BUG: 1250810
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/11818
Tested-by: Gluster Build System 
Reviewed-by: Raghavendra G 
Tested-by: NetBSD Build System 
(cherry picked from commit 3403370ebeaf16567b79022c6ac48b2e0cd50db5)
Reviewed-on: http://review.gluster.org/11848

glusterd: nfs,shd,quotad,snapd daemons refactoring

2015-02-20T12:04:08+00:00

This patch ports nfs, shd, quotad & snapd with the approach suggested in
http://www.gluster.org/pipermail/gluster-devel/2014-December/043180.html

Change-Id: I4ea5b38793f87fc85cc9d2cf873727351dedffd2
BUG: 1191486
Signed-off-by: Atin Mukherjee 
Signed-off-by:  Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/9428
Tested-by: Gluster Build System 
Reviewed-by: Anand Nekkunti

client/rpc: Add ping and msgs stats

2014-07-31T16:03:56+00:00

This can be seen as below,

># cat $META/graphs/active/vol-client-0/private |grep ping_msgs_sent
ping_msgs_sent = 2

># cat $META/graphs/active/vol-client-0/private |grep "^msgs_sent"
msgs_sent = 13

where $META is //.meta

Change-Id: I2107ec2b045bac701377760635e18758adb943a3
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/8285
Tested-by: Gluster Build System 
Reviewed-by: Atin Mukherjee 
Reviewed-by: Anand Avati

glusterd: Ping timer implmentation

2014-04-29T21:23:51+00:00

This patch refactors the existing client ping timer implementation, and makes
use of the common code for implementing both client ping timer and the
glusterd ping timer.

A new gluster rpc program for ping is introduced. The ping timer is only
started for peers that have this new program. The deafult glusterd ping
timeout is 30 seconds. It is configurable by setting the option
'ping-timeout' in glusterd.vol .

Also, this patch introduces changes in the glusterd-handshake path. The client
programs for a peer are now set in the callback of dump_versions, for both
the older handshake and the newer op-version handshake. This is the only place
in the handshake process where we know what programs a peer supports.

Change-Id: I035815ac13449ca47080ecc3253c0a9afbe9016a
BUG: 1038261
Signed-off-by: Vijaikumar M 
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/5202
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

rpc: transport may be destroyed while rpc isn't

2014-03-06T05:26:59+00:00

rpc_clnt object is destroyed after the corresponding transport object is
destroyed. But rpc_clnt_reconnect, a timer driven function, refers to
the transport object beyond its 'life'. Instead, using the embedded
connection object prevents use after free problem wrt transport object.

Also, access transport object under conn->lock.

Change-Id: Iae28e8a657d02689963c510114ad7cb7e6764e62
BUG: 962619
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/6751
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

rpc,glusterd: Use rpc_clnt notifyfn to cleanup mydata

2013-12-16T13:03:19+00:00

rpc:
- On a RPC_TRANSPORT_CLEANUP event, rpc_clnt_notify calls the registered
  notifyfn with a RPC_CLNT_DESTROY event. The notifyfn should properly
  cleanup the saved mydata on this event.
- Break the reconnect chain when an rpc client is disabled. This will
  prevent new disconnect events which can lead to crashes.

glusterd:
- Added support for RPC_CLNT_DESTROY in glusterd_brick_rpc_notify
- Use a common glusterd_rpc_clnt_unref() function throught glusterd in
  place of rpc_clnt_unref(). This function correctly gives up the
  big-lock before performing the unref.

Change-Id: I93230441c5089039643fc9f5632477ef1b695348
BUG: 962619
Signed-off-by: Kaushal M 
Reviewed-on: http://review.gluster.org/5512
Tested-by: Gluster Build System 
Reviewed-by: Krishnan Parthasarathi 
Reviewed-by: Vijay Bellur

rpc: Cleanup rpc object in TRANSPORT_CLEANUP event

2013-06-16T05:34:28+00:00

rpc_transport object should be alive as long as the rpc_clnt object is
alive. To ensure this, on rpc_clnt's last unref, we cleanup the
corresponding rpc_transport object and complete the rpc_clnt cleanup
later, in a bottom-up fashion.

Introduced rpc_clnt_is_disabled, to allow higher layers to differentiate
between the 'final'[1] disconnect triggered from upper layers, and a
normal disconnect. This differentiation helps in cleaning up resources,
at higher layers, in a race-free manner.

[1] - 'final' here means that the rpc and the associated connection, is
not going to be used anymore. eg - glusterd_brick_disconnect on
volume-stop.

Change-Id: I2ecf891a36e3b02cd9eacca964e659525d1bbc6e
BUG: 962619
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/5107
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati