LUDOC-293 protocol: Merge all recent patches

[doc/protocol.git] / ldlm_gl_callback.txt

diff --git a/ldlm_gl_callback.txt b/ldlm_gl_callback.txt
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+Command 104: LDLM_GL_CALLBACK
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+[[ldlm-gl-callback-rpc]]
+
+An RPC that assists with getting a lock back from an entity that has
+it.
+
+.LDLM_GL_CALLBACK Generic Packet Structure
+image::ldlm-gl-callback-generic.png["LDLM_GL_CALLBACK Generic Packet Structure",height=100]
+
+//////////////////////////////////////////////////////////////////////
+The ldlm-gl-callback-generic.png diagram resemgles this text
+art:
+
+       LDLM_GL_CALLBACK:
+      --request---------------------
+      | ptlrpc_body | ldlm_request |
+      ------------------------------
+      --reply------------------
+      | ptlrpc_body | ost_lvb |
+      -------------------------
+//////////////////////////////////////////////////////////////////////
+
+The request RPC resembles the simplest LDLM_ENQUEUE RPC, but only
+identifies the relevant resource that the destination entity already
+had a lock on. It asks the recipient to flush its dirty write cache,
+and notify the requester of size and time attributes once that is
+done.  The reply updates the attributes on the requester.
+
+'ptlrpc_body'::
+RPC descriptor.
+
+'ldlm_request'::
+Description of the lock being requested. Which resource is the target,
+what lock is current, and what lock desired.
+
+'ost_lvb'::
+Attribute data associated with a resource on an OST.
+