afr: arbiter xlator

This patch adds the arbiter translator into the tree. This is a server
side xlator used for replica 3 volumes. It sits above posix and will be
loaded on the 3rd (last) brick of every afr subvolume in a replica 3
configuration. It intercepts inode read/write operations: reads are
unwound with ENOTCONN, inode writes are unwound with success without
actually passing them down to posix. Metadata operations are allowed to
pass through.

The CLI for creating a 3 way replica with arbiter is also added but kept
disabled (A 'normal' 3 way replica is created instead).

This patch is a part of the arbiter logic implementation for 3 way AFR,
details of which can be found at http://review.gluster.org/#/c/9656/

Change-Id: I395b81f49d5da52c466daf5c8518f1bbad9c16fa
BUG: 1199985
Signed-off-by: Ravishankar N <ravishankar@redhat.com>
Reviewed-on: http://review.gluster.org/9840
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

cli/src/cli-cmd-parser.c

@@ -437,12 +437,13 @@ cli_cmd_volume_create_parse (struct cli_state *state, const char **words,
         char    *bricks = NULL;
         int32_t brick_count = 0;
         char    *opwords[] = { "replica", "stripe", "transport", "disperse",
-                               "redundancy", "disperse-data", NULL };
+                               "redundancy", "disperse-data", "arbiter", NULL };
 
         char    *w = NULL;
         char    *ptr = NULL;
         int      op_count = 0;
         int32_t  replica_count = 1;
+        int32_t  arbiter_count = 0;
         int32_t  stripe_count = 1;
         int32_t  disperse_count = -1;
         int32_t  redundancy_count = -1;
@@ -521,6 +522,25 @@ cli_cmd_volume_create_parse (struct cli_state *state, const char **words,
                                 goto out;
 
                         index += 2;
+                        if (!strcmp (words[index], "arbiter")) {
+                                ret = gf_string2int (words[index+1],
+                                                     &arbiter_count);
+                                if (ret == -1 || arbiter_count != 1 ||
+                                    replica_count != 3) {
+                                        cli_err ("For arbiter configuration, "
+                                                 "replica count must be 3 and "
+                                                 "arbiter count must be 1. "
+                                                 "The 3rd brick of the replica "
+                                                 "will be the arbiter.");
+                                        ret = -1;
+                                        goto out;
+                                }
+                                ret = dict_set_int32 (dict, "arbiter-count",
+                                                      arbiter_count);
+                                if (ret)
+                                        goto out;
+                                index += 2;
+                        }
 
                 } else if ((strcmp (w, "stripe")) == 0) {
                         switch (type) {

cli/src/cli-cmd-volume.c

@@ -2544,7 +2544,8 @@ struct cli_cmd volume_cmds[] = {
           cli_cmd_volume_info_cbk,
           "list information of all volumes"},
 
-        { "volume create <NEW-VOLNAME> [stripe <COUNT>] [replica <COUNT>] "
+        { "volume create <NEW-VOLNAME> [stripe <COUNT>] "
+          "[replica <COUNT> [arbiter <COUNT>]] "
           "[disperse [<COUNT>]] [disperse-data <COUNT>] [redundancy <COUNT>] "
           "[transport <tcp|rdma|tcp,rdma>] <NEW-BRICK>"
 #ifdef HAVE_BD_XLATOR

configure.ac

@@ -115,6 +115,8 @@ AC_CONFIG_FILES([Makefile
                 xlators/protocol/server/Makefile
                 xlators/protocol/server/src/Makefile
                 xlators/features/Makefile
+                xlators/features/arbiter/Makefile
+                xlators/features/arbiter/src/Makefile
                 xlators/features/changelog/Makefile
                 xlators/features/changelog/src/Makefile
                 xlators/features/changelog/lib/Makefile

xlators/features/Makefile.am

@@ -1,4 +1,4 @@
-SUBDIRS = locks quota read-only mac-compat quiesce marker index barrier \
+SUBDIRS = locks quota read-only mac-compat quiesce marker index barrier arbiter\
           protect compress changelog changetimerecorder ganesha gfid-access $(GLUPY_SUBDIR) qemu-block \
           upcall snapview-client snapview-server trash #path-converter # filter
 

xlators/features/arbiter/Makefile.am

@@ -0,0 +1,3 @@
+SUBDIRS = src
+
+CLEANFILES =

xlators/features/arbiter/src/Makefile.am

@@ -0,0 +1,16 @@
+xlator_LTLIBRARIES = arbiter.la
+xlatordir = $(libdir)/glusterfs/$(PACKAGE_VERSION)/xlator/features
+
+arbiter_la_LDFLAGS = -module -avoid-version
+
+arbiter_la_SOURCES = arbiter.c
+_la_LIBADD = $(top_builddir)/libglusterfs/src/libglusterfs.la
+arbiter_la_LIBADD = $(top_builddir)/libglusterfs/src/libglusterfs.la
+
+noinst_HEADERS = arbiter.h arbiter-mem-types.h
+
+AM_CPPFLAGS = $(GF_CPPFLAGS) -I$(top_srcdir)/libglusterfs/src
+
+AM_CFLAGS = -Wall $(GF_CFLAGS)
+
+CLEANFILES =

xlators/features/arbiter/src/arbiter-mem-types.h

@@ -0,0 +1,19 @@
+/*
+  Copyright (c) 2015 Red Hat, Inc. <http://www.redhat.com>
+  This file is part of GlusterFS.
+  This file is licensed to you under your choice of the GNU Lesser
+  General Public License, version 3 or any later version (LGPLv3 or
+  later), or the GNU General Public License, version 2 (GPLv2), in all
+  cases as published by the Free Software Foundation.
+*/
+
+#ifndef __ARBITER_MEM_TYPES_H__
+#define __ARBITER_MEM_TYPES_H__
+#include "mem-types.h"
+
+typedef enum gf_arbiter_mem_types_ {
+        gf_arbiter_mt_inode_ctx_t =  gf_common_mt_end + 1,
+        gf_arbiter_mt_iatt,
+        gf_arbiter_mt_end
+} gf_arbiter_mem_types_t;
+#endif