glusterfs-afrv1.git/xlators/mgmt/glusterd, 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: Fixed spurious wakeups in glusterd syncops

2013-04-17T12:46:43+00:00

glusterd syncops perform a barrier_wake whenever rpc_clnt_submit returned -1.
This is based on the wrong assumption that the cbkfn wasn't called.
This would result in one more wakeup than there ought to be.

BUG: 948686
Change-Id: I839fd218a81255fe50c2047d67461d45360e894d
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/4834
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

glusterd: fix segfault on volume status detail

2013-04-16T16:43:23+00:00

If for some reason glusterd_get_brick_root() fails,
it frees the gf_strdup'ed *mount_point in its own error path,
and returns -1.

Unfortunately it already had assigned that pointer value
to the output argument, the caller function
glusterd_add_brick_detail() sees a non-NULL pointer,
and free() again: segfault.

Could be fixed with a one-liner (*mount_point = NULL)
in the error path, but I think glusterd_get_brick_root()
should only assign to the output argument once all checks passed,
so I use a local temporary pointer, which increases the patch a bit.

Change-Id: I3f3035f01e80a5e9bdf2da895e4cf7baa3dfbd2f
BUG: 919352
Signed-off-by: Lars Ellenberg 
Reviewed-on: http://review.gluster.org/4646
Reviewed-by: Krishnan Parthasarathi 
Tested-by: Gluster Build System 
Reviewed-on: http://review.gluster.org/4841
Reviewed-by: Jeff Darcy

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: Fixed volume-sync in synctask codepath.

2013-04-12T12:59:05+00:00

Change-Id: I2911d3ac80825310f84c5ba6bd7890e65e1ee219
BUG: 950048
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/4643
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

mgmt/glusterd: Start fs-crawl in separate thread so as not to block epoll

2013-03-19T17:29:59+00:00

tests/basic/quota.t covers test case for this.

Patch is only for 3.4 branch, http://review.gluster.org/4495 fixes the issue
in master.

Change-Id: I92674f5413441cc896245d5b3d0925f44ce8b2d3
BUG: 919998
Signed-off-by: Varun Shastry 
Reviewed-on: http://review.gluster.org/4680
Reviewed-by: Amar Tumballi 
Reviewed-by: Jeff Darcy 
Tested-by: Gluster Build System

glusterd: Increasing throughput of synctask based mgmt ops.

2013-03-07T06:06:30+00:00

Change-Id: Ibd963f78707b157fc4c9729aa87206cfd5ecfe81
BUG: 913662
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/4638
Tested-by: Gluster Build System 
Reviewed-by: Jeff Darcy

volgen: Use bind-address option for bricks when option set on glusterd

2013-03-07T06:05:38+00:00

Brick processes listen on all the interfaces on a given port.
When multiple glusterds run on one machine, glusterd assumes
that it 'owns' the ports on that machine. This can lead to the
different glusterd instances to step on each other's ports.
This fix ensures that brick processes listen only on the its
host IP when glusterd has bind-address option set.

Change-Id: I4c1b05643c64d3098bf56e977e768e611ffce0f5
BUG: 913662
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/4637
Tested-by: Gluster Build System 
Reviewed-by: Jeff Darcy

Do not call xdr_string() with a NULL error message

2013-03-06T05:04:09+00:00

It is illegal to call xdr_string() with a NULL string. Linux
just retruns false, NetBSD gets a SIGSEGV when xdr_string()
calls strlen(NULL)

BUG: 916439
Change-Id: Ia958470ada6e8e55a86d439922ec942d038f5f13
Original-author: Emmanuel Dreyfus 
Signed-off-by: Emmanuel Dreyfus 
Signed-off-by: Jeff Darcy 
Reviewed-on: http://review.gluster.org/4629

glusterd: Fix check for task-id existence in 'volume status'

2013-03-05T09:05:59+00:00

This fixes the issue of task-id tests failing randomly. The condition used to
check rebalance/remove-brick was running was wrong, which could lead to the
task-id for these tasks to not be displayed even when the actual commit hadn't
occured.

BUG: 857330
Change-Id: I0f86c6bbe7acec586ee0ea6e663369ea26171904
Signed-off-by: Kaushal M 
Reviewed-on: http://review.gluster.org/4617
Reviewed-by: Jeff Darcy 
Tested-by: Gluster Build System