Reconnect hosts for master

_oasis

@@ -30,7 +30,7 @@ Executable "xenvmd"
   MainIs:             xenvmd.ml
   Custom:             true
   Install:            false
-  BuildDepends:       lwt, lwt.unix, mirage-block-unix, mirage-clock-unix, devmapper, threads, lvm, cstruct, oUnit, io-page, io-page.unix, cmdliner, sexplib.syntax, xenvmidl, lvm, lvm.mapper, shared-block-ring
+  BuildDepends:       lwt, lwt.unix, mirage-block-unix, mirage-clock-unix, devmapper, threads, lvm, cstruct, oUnit, io-page, io-page.unix, stringext, cmdliner, sexplib.syntax, xenvmidl, lvm, lvm.mapper, shared-block-ring
 
 Executable "xenvm"
   ByteOpt:            -warn-error +a

_tags

@@ -1,5 +1,5 @@
 # OASIS_START
-# DO NOT EDIT (digest: ff372a3fb61a268f33926cbcbfd6c5ab)
+# DO NOT EDIT (digest: 2190fe0a8a00a6b8cc32c1b1dff4f3d1)
 # Ignore VCS directories, you can use the same kind of rule outside
 # OASIS_START/STOP if you want to exclude directories that contains
 # useless stuff for the build process
@@ -52,6 +52,7 @@ true: annot, bin_annot
 <xenvmd/xenvmd.{native,byte}>: pkg_sexplib
 <xenvmd/xenvmd.{native,byte}>: pkg_sexplib.syntax
 <xenvmd/xenvmd.{native,byte}>: pkg_shared-block-ring
+<xenvmd/xenvmd.{native,byte}>: pkg_stringext
 <xenvmd/xenvmd.{native,byte}>: pkg_threads
 <xenvmd/xenvmd.{native,byte}>: use_xenvmidl
 <xenvmd/*.ml{,i,y}>: pkg_cmdliner
@@ -72,6 +73,7 @@ true: annot, bin_annot
 <xenvmd/*.ml{,i,y}>: pkg_sexplib
 <xenvmd/*.ml{,i,y}>: pkg_sexplib.syntax
 <xenvmd/*.ml{,i,y}>: pkg_shared-block-ring
+<xenvmd/*.ml{,i,y}>: pkg_stringext
 <xenvmd/*.ml{,i,y}>: pkg_threads
 <xenvmd/*.ml{,i,y}>: use_xenvmidl
 <xenvmd/xenvmd.{native,byte}>: custom

cleanup.sh

@@ -22,4 +22,4 @@ if [ "$USE_MOCK" -eq "0" ]; then
   losetup -d $LOOP
 fi
 
-rm -f localJournal bigdisk *.out djstest-* dm-mock
+rm -f localJournal bigdisk *.out*  djstest-* dm-mock

opam

@@ -27,4 +27,5 @@ depends: [
   "ounit"
   "oasis"
   "ocveralls"
+  "stringext"
 ]

setup.sh

@@ -69,14 +69,20 @@ cat test.local_allocator.conf.in | sed -r "s|@BIGDISK@|$LOOP|g"  | sed -r "s|@HO
 sleep 30
 ./xenvm.native host-list /dev/djstest --configdir /tmp/xenvm.d $MOCK_ARG
 
+# Let's check that xenvmd retains its list of connected hosts over a restart
+./xenvm.native host-list /dev/djstest --configdir /tmp/xenvm.d $MOCK_ARG | sort > host-list.out
+kill `cat /tmp/xenvmd.lock`
+./xenvmd.native --config ./test.xenvmd.conf > xenvmd.log.2 &
+sleep 10
+./xenvm.native host-list /dev/djstest --configdir /tmp/xenvm.d $MOCK_ARG | sort > host-list.out2
+diff -u host-list.out host-list.out2 
+
 # destroy hosts
 ./xenvm.native host-disconnect /dev/djstest host2 --configdir /tmp/xenvm.d $MOCK_ARG
 ./xenvm.native host-destroy /dev/djstest host2 --configdir /tmp/xenvm.d $MOCK_ARG
 ./xenvm.native host-disconnect /dev/djstest host1 --configdir /tmp/xenvm.d $MOCK_ARG
 ./xenvm.native host-destroy /dev/djstest host1 --configdir /tmp/xenvm.d $MOCK_ARG
 
-./xenvm.native host-list /dev/djstest --configdir /tmp/xenvm.d $MOCK_ARG
-
 #shutdown
 ./xenvm.native lvchange -an /dev/djstest/live --configdir /tmp/xenvm.d $MOCK_ARG || true
 ./xenvm.native shutdown /dev/djstest --configdir /tmp/xenvm.d $MOCK_ARG

xenvmd/xenvmd.ml

@@ -31,6 +31,8 @@ let fatal_error_t msg =
   error "%s" msg;
   fail (Failure msg)
 
+let connected_tag = "xenvm_connected"
+
 let fatal_error msg m = m >>= function
   | `Error (`Msg x) -> fatal_error_t (msg ^ ": " ^ x)
   | `Error `Suspended -> fatal_error_t (msg ^ ": queue is suspended")
@@ -291,6 +293,11 @@ module VolumeManager = struct
       end else begin
         match Vg_IO.find vg toLVM, Vg_IO.find vg fromLVM, Vg_IO.find vg freeLVM with
         | Some toLVM_id, Some fromLVM_id, Some freeLVM_id ->
+          (* Persist at this point that we're going to connect this host *)
+          (* All of the following logic is idempotent *)
+          write (fun vg ->
+              Lvm.Vg.add_tag vg toLVM connected_tag
+            ) >>= fun () -> 
           Hashtbl.replace host_connections name Xenvm_interface.Resuming_to_LVM;
           let background_t () = 
             Vg_IO.Volume.connect toLVM_id
@@ -305,7 +312,6 @@ module VolumeManager = struct
             ToLVM.resume toLVM_q
             >>= fun () ->
 
-
             Vg_IO.Volume.connect fromLVM_id
             >>= function
             | `Error _ -> fail (Failure (Printf.sprintf "Failed to open %s" fromLVM))
@@ -394,14 +400,18 @@ module VolumeManager = struct
           let to_lvm = List.assoc name !to_LVMs in
           debug "Suspending ToLVM queue for %s" name;
           ToLVM.suspend to_lvm
-          >>= fun () ->
+          >>= fun () -> 
           (* There may still be updates in the ToLVM queue *)
           Lwt_mutex.with_lock flush_m (fun () -> flush_already_locked name)
           >>= fun () ->
           debug "ToLVM queue for %s has been suspended and flushed" name;
           to_LVMs := List.filter (fun (n, _) -> n <> name) !to_LVMs;
           from_LVMs := List.filter (fun (n, _) -> n <> name) !from_LVMs;
           free_LVs := List.filter (fun (n, _) -> n <> name) !free_LVs;
+          let toLVM = toLVM name in
+          write (fun vg ->
+              Lvm.Vg.remove_tag vg toLVM connected_tag
+            ) >>= fun () ->
           Hashtbl.remove host_connections name;
           return ()
         | x ->
@@ -455,6 +465,30 @@ module VolumeManager = struct
             else None in
           return { Xenvm_interface.name; connection_state; fromLVM; toLVM; freeExtents }
         ) !to_LVMs
+
+    let reconnect_all () =
+      read (fun vg ->
+          debug "Reconnecting";
+          Lvm.Vg.LVs.fold (fun key v acc ->
+              debug "Checking LV: %s" v.Lvm.Lv.name;
+              let name = v.Lvm.Lv.name in
+              match Stringext.split name ~on:'-' |> List.rev with
+              | "toLVM" :: host_bits ->
+                let host = String.concat "-" (List.rev host_bits) in
+                debug "This is a 'toLVM' LV";
+                (* It's a toLVM - check to see whether it has the 'connected' flag *)
+                let tags = List.map Lvm.Name.Tag.to_string v.Lvm.Lv.tags in
+                let was_connected = List.mem connected_tag tags in
+                debug "host=%s was_connected=%b" host was_connected;
+                (host,was_connected)::acc
+              | e ->
+                debug "got list: %s" (String.concat "," e);
+                acc)
+            vg.Lvm.Vg.lvs [] |> Lwt.return
+        ) >>= fun host_states ->
+      Lwt_list.iter_s (fun (host, was_connected) ->
+          if was_connected then connect host else disconnect host) host_states
+
   end
 
   let flush_all () =
@@ -740,7 +774,9 @@ let run port sock_path config =
     >>= fun () ->
     FreePool.start Xenvm_interface._journal_name
     >>= fun () ->
-
+    VolumeManager.Host.reconnect_all ()
+    >>= fun () -> 
+
     let rec service_queues () =
       (* 0. Have any local allocators restarted? *)
       FreePool.resend_free_volumes config