tasks/kclient: add 'debug' option

Signed-off-by: John Spray <john.spray@redhat.com>

tasks/kclient.py

@@ -4,6 +4,7 @@ Mount/unmount a ``kernel`` client.
 import contextlib
 import logging
 
+from teuthology.misc import deep_merge
 from teuthology import misc
 from cephfs.kernel_mount import KernelMount
 
@@ -34,17 +35,38 @@ def task(ctx, config):
         - kclient: [client.1]
         - interactive:
 
+
+    Pass a dictionary instead of lists to specify per-client config:
+
+        tasks:
+        -kclient:
+            client.0:
+                debug: true
+
     :param ctx: Context
     :param config: Configuration
     """
     log.info('Mounting kernel clients...')
-    assert config is None or isinstance(config, list), \
+    assert config is None or isinstance(config, list) or isinstance(config, dict), \
         "task kclient got invalid config"
 
     if config is None:
         config = ['client.{id}'.format(id=id_)
                   for id_ in misc.all_roles_of_type(ctx.cluster, 'client')]
-    clients = list(misc.get_clients(ctx=ctx, roles=config))
+
+    if isinstance(config, list):
+        client_roles = config
+        config = dict([r, dict()] for r in client_roles)
+    elif isinstance(config, dict):
+        client_roles = config.keys()
+    else:
+        raise ValueError("Invalid config object: {0} ({1})".format(config, config.__class__))
+
+    # config has been converted to a dict by this point
+    overrides = ctx.config.get('overrides', {})
+    deep_merge(config, overrides.get('kclient', {}))
+
+    clients = list(misc.get_clients(ctx=ctx, roles=client_roles))
 
     test_dir = misc.get_testdir(ctx)
 
@@ -69,6 +91,11 @@ def task(ctx, config):
 
         mounts[id_] = kernel_mount
 
+        client_config = config["client.{0}".format(id_)]
+        if client_config.get('debug', False):
+            remote.run(args=["sudo", "bash", "-c", "echo 'module ceph +p' > /sys/kernel/debug/dynamic_debug/control"])
+            remote.run(args=["sudo", "bash", "-c", "echo 'module libceph +p' > /sys/kernel/debug/dynamic_debug/control"])
+
         kernel_mount.mount()
 
     ctx.mounts = mounts