Upcall: New xlator to store various states and send cbk events

Framework on the server-side, to handle certain state of the files
accessed and send notifications to the clients connected.

A generic and extensible framework, used to maintain states in
the glusterfsd process for each of the files accessed
(including the clients info doing the fops) and send
notifications to the respective glusterfs clients incase of
any change in that state.

This patch handles "Inode Update/Invalidation" upcall event.

Feature page:
        URL: http://www.gluster.org/community/documentation/index.php/Features/Upcall-infrastructure

Below link has a writeup which explains the code changes done -
        URL: https://soumyakoduri.wordpress.com/2015/02/25/glusterfs-understanding-upcall-infrastructure-and-cache-invalidation-support/

Change-Id: Ie3d724be9a3419fcf18901a753e8ec2df2ac802f
BUG: 1200262
Signed-off-by: Soumya Koduri <skoduri@redhat.com>
Reviewed-on: http://review.gluster.org/9535
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>

3 files changed, 28 insertions, 0 deletions

diff --git a/libglusterfs/src/defaults.c b/libglusterfs/src/defaults.c
index 599f9477dca..a4f8f924b17 100644
--- a/libglusterfs/src/defaults.c
+++ b/libglusterfs/src/defaults.c
@@ -2287,6 +2287,21 @@ default_notify (xlator_t *this, int32_t event, void *data, ...)
                 }
         }
         break;
+        case GF_EVENT_UPCALL:
+        {
+                xlator_list_t *parent = this->parents;
+
+                if (!parent && this->ctx && this->ctx->master)
+                        xlator_notify (this->ctx->master, event, data, NULL);
+
+                while (parent) {
+                        if (parent->xlator->init_succeeded)
+                                xlator_notify (parent->xlator, event,
+                                               data, NULL);
+                        parent = parent->next;
+                }
+        }
+        break;
         default:
         {
                 xlator_list_t *parent = this->parents;
diff --git a/libglusterfs/src/glfs-message-id.h b/libglusterfs/src/glfs-message-id.h
index 35abe472aab..c977206c44d 100644
--- a/libglusterfs/src/glfs-message-id.h
+++ b/libglusterfs/src/glfs-message-id.h
@@ -72,6 +72,10 @@
 #define GLFS_MSGID_COMP_COMMON_END         (GLFS_MSGID_COMP_COMMON +\
                                            GLFS_MSGID_SEGMENT)
 
+#define GLFS_MSGID_COMP_UPCALL             GLFS_MSGID_COMP_COMMON_END
+#define GLFS_MSGID_COMP_UPCALL_END         (GLFS_MSGID_COMP_UPCALL +\
+                                           GLFS_MSGID_SEGMENT)
+
 /* --- new segments for messages goes above this line --- */
 
 #endif /* !_GLFS_MESSAGE_ID_H_ */
diff --git a/libglusterfs/src/glusterfs.h b/libglusterfs/src/glusterfs.h
index c482b3d2242..d5a604d0341 100644
--- a/libglusterfs/src/glusterfs.h
+++ b/libglusterfs/src/glusterfs.h
@@ -562,6 +562,7 @@ typedef enum {
         GF_EVENT_VOLUME_DEFRAG,
         GF_EVENT_PARENT_DOWN,
         GF_EVENT_VOLUME_BARRIER_OP,
+        GF_EVENT_UPCALL,
         GF_EVENT_MAXVAL,
 } glusterfs_event_t;
 
@@ -574,6 +575,14 @@ struct gf_flock {
         gf_lkowner_t l_owner;
 };
 
+struct gf_upcall {
+        char  *client_uid;
+	char  gfid[16];
+        u_int event_type;
+        u_int flags;
+        u_int expire_time_attr;
+};
+
 #define GF_MUST_CHECK __attribute__((warn_unused_result))
 /*
  * Some macros (e.g. ALLOC_OR_GOTO) set variables in function scope, but the