glusterfs.git/xlators/mgmt/glusterd/src/glusterd-utils.h, branch v3.4.0beta1

glusterd: big lock - a coarse-grained locking to prevent races

2013-04-17T12:48:50+00:00

There are primarily three lists that are part of glusterd process,
that are concurrently accessed. Namely, priv->volumes, priv->peers
and volinfo->bricks_list.

Big-lock approach
-----------------
WHAT IS IT?
Big lock is a coarse-grained lock which protects all three
lists, mentioned above, from racy access.

HOW DOES IT WORK?
At any given point in time, glusterd's thread(s) are in execution
_iff_ there is a preceding, inbound network event. Of course, the
sigwaiter thread and timer thread are exceptions.
A network event is an external trigger to glusterd, via the epoll
thread, in the form of POLLIN and POLLERR.
As long as we take the big-lock at all such entry points and yield
it when we are done, we are guaranteed that all the network events,
accessing the global lists, are serialised.

This amounts to holding the big lock at
- all the handlers of all the actors in glusterd. (POLLIN)
- all the cbks in glusterd. (POLLIN)
- rpc_notify (DISCONNECT event), if we access/modify
  one of the three lists. (POLLERR)

In the case of synctask'ized volume operations, we must remember that,
if we held the big lock for the entire duration of the handler,
we may block other non-synctask rpc actors from executing.
For eg, volume-start would block in PMAP SIGNIN, if done incorrectly.
To prevent this, we need to yield the big lock, when we yield the
synctask, and reacquire on waking up of the synctask.

BUG: 948686
Change-Id: I429832f1fed67bcac0813403d58346558a403ce9
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/4835
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

glusterd: allow multiple instances of glusterd on one machine

2013-04-16T11:48:58+00:00

This is needed to support automated testing of cluster-communication
features such as probing and quorum.  In order to use this, you need to
do the following preparatory steps.

* Copy /var/lib/glusterd to another directory for each virtual host

* Ensure that each virtual host has a different UUID in its glusterd.info

Now you can start each copy of glusterd with the following xlator-options.

* management.transport.socket.bind-address=$ip_address

* management.working-directory=$unique_working_directory

You can use 127.x.y.z addresses for binding without needing to assign
them to interfaces explicitly.  Note that you must use addresses, not
names, because of some stuff in the socket code that's not worth fixing
just for this usage, but after that you can use names in /etc/hosts
instead.

At this point you can issue CLI commands to a specific glusterd using
the --remote-host option.  So far probe, volume create/start/stop,
mount, and basic I/O all seem to work as expected with multiple
instances.

Change-Id: I1beabb44cff8763d2774bc208b2ffcda27c1a550
BUG: 913555
Original-author: Jeff Darcy 
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/4838
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

glusterd : Made volume clear-locks use synctask framework.

2013-02-08T22:08:22+00:00

Change-Id: Ia1fe3d0500d999c1f95b43c9e53947834e39d680
BUG: 852147
Signed-off-by: Avra Sengupta 
Reviewed-on: http://review.gluster.org/4490
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

glusterd: Moved node rsp functions to glusterd-utils.c

2013-02-03T19:52:58+00:00

Change-Id: Ib4c4794563a5a694fab16f17c642f788399462f6
BUG: 852147
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/4295
Tested-by: Gluster Build System 
Reviewed-by: Kaushal M 
Reviewed-by: Anand Avati

glusterd: make 'glusterd_is_local_addr' return bool

2013-01-26T19:39:34+00:00

Change-Id: Id3bd0bfc4802c166f7a32b0cc6a726aeb5617b5d
BUG: 890618
Signed-off-by: JulesWang 
Reviewed-on: http://review.gluster.org/4427
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

glusterd, cli: Task id's for async tasks

2012-12-19T21:32:49+00:00

This patch introduces task-id's for async tasks like rebalance, remove-brick and
replace-brick. An id is generated for each task when it is started and displayed
to the user in cli output. The status of running tasks is also included in the
output of "volume status" along with its id, so that a user can easily track the
progress of an async task.

Also,
 * added tests for this feature into the regression test suite.
 * added a python script for creating files, 'create-files.py', courtesy
   Vijaykumar Koppad (vkoppad@redhat.com) into the test suite.

This patch reverts the revert commit 698deb33d731df6de84da8ae8ee4045e1543a168.

BUG: 857330
Change-Id: Id43d7cb629a38f47f733fbc18cb4c5f2f0327c7a
Signed-off-by: Kaushal M 
Reviewed-on: http://review.gluster.org/4294
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

Revert "glusterd, cli: Task id's for async tasks"

2012-12-04T23:59:52+00:00

This reverts commit ed15521d4e5af2b52b78fd33711e7562f5273bc6

Strangely, the test scripts are "silently" passing for failures too. Reverting patch for now.

Change-Id: I802ec1634c7863dc373cc7dc4a47bd4baa72764e
Reviewed-on: http://review.gluster.org/4267
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

glusterd, cli: Task id's for async tasks

2012-12-04T22:44:36+00:00

This patch introduces task-id's for async tasks like rebalance, remove-brick and
replace-brick. An id is generated for each task when it is started and displayed
to the user in cli output. The status of running tasks is also included in the
output of "volume status" along with its id, so that a user can easily track the
progress of an async task.

Also,
 * added tests for this feature into the regression test suite.
 * added a python script for creating files, 'create-files.py', courtesy
   Vijaykumar Koppad (vkoppad@redhat.com) into the test suite.

Change-Id: Ib0c0d12e0d6c8f72ace48d303d7ff3102157e876
BUG: 857330
Signed-off-by: Kaushal M 
Reviewed-on: http://review.gluster.org/3942
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

mgmt/glusterd: Consider nodesvc to be running after online

2012-11-30T01:34:54+00:00

Definition of online in the message below is that the
RPC_CLNT_CONNECT event arrives for the nfs/self-heal-daemon process.

For automated tests, sometimes the script needs to wait until
self-heal-daemon comes online, so that the relevant
commands can be executed. Gluster volume status before this change
printed whether the self-heal-daemon is running or not based on the
lock availability on the pidfile. But there is a small window where
the lock on pid file is present but the process is still not
online. So the commands that were depending on this kept failing in
the test script.

Change-Id: I0e44e18b08d7b653d34fa170c1f187d91c888cd9
BUG: 858212
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/4236
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

geo-rep / gsyncd,glusterd: do not hardcode socket path

2012-11-29T00:54:07+00:00

... in gsyncd python code. Indeed, use the configuration
mechanism to set it suitably from glusterd.

Change-Id: I9fe2088b14d28588d1e64fe892740cc5755b8365
BUG: 868877
Signed-off-by: Csaba Henk 
Reviewed-on: http://review.gluster.org/4143
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati