MigrationModule: new option --target-deficit-mode

* Control behavior of migrations when the number of replicas requested
  exceeds the number of pools available to satisfy that request.

* Permitted values are "wait" (wait until pools become available), or
  "limit" (job will end when all available pools are hosting a replica
  if the request cannot be met).

modules/dcache-qos/src/main/java/org/dcache/qos/services/adjuster/adjusters/CopyAdjuster.java

@@ -136,7 +136,8 @@ private synchronized void createTask(PoolManagerPoolInformation targetInfo, Stri
               false,   // compute checksum on update; should not happen
               false,   // force copy even if pool is not readable
               true,    // maintain atime
-              1);      // only one copy per task
+              1,       // only one copy per task
+              true);   // wait for new targets if necessary
 
         createTask(taskParameters, source);
 

modules/dcache-resilience/src/main/java/org/dcache/resilience/handlers/FileOperationHandler.java

@@ -380,7 +380,8 @@ public Task handleMakeOneCopy(FileAttributes attributes) {
               false,  // compute checksum on update; should not happen
               false,  // force copy even if pool not readable
               true,   // maintain atime
-              1);
+              1,       // only one copy per task
+              true);   // wait for new targets if necessary
 
         Task task = new Task(taskParameters, completionHandler, source, pnfsId,
               ReplicaState.CACHED, ONLINE_STICKY_RECORD,

modules/dcache/src/main/java/org/dcache/pool/migration/Job.java

@@ -109,7 +109,7 @@ public Job(MigrationContext context, JobDefinition definition) {
               context.getExecutor(), definition.selectionStrategy,
               definition.poolList, definition.isEager, definition.isMetaOnly,
               definition.computeChecksumOnUpdate, definition.forceSourceMode,
-              definition.maintainAtime, definition.replicas);
+              definition.maintainAtime, definition.replicas, definition.waitForTargets);
 
         _pinPrefix = context.getPinManagerStub().getDestinationPath().getDestinationAddress()
               .getCellName();

modules/dcache/src/main/java/org/dcache/pool/migration/JobDefinition.java

@@ -103,6 +103,12 @@ public class JobDefinition {
      */
     public final int replicas;
 
+    /**
+     * Whether to wait for targets to become available to satisfy number of replicas.
+     */
+    public final boolean waitForTargets;
+
+
     public JobDefinition(Predicate<CacheEntry> filter,
           CacheEntryMode sourceMode,
           CacheEntryMode targetMode,
@@ -120,7 +126,8 @@ public JobDefinition(Predicate<CacheEntry> filter,
           boolean maintainAtime,
           Expression pauseWhen,
           Expression stopWhen,
-          boolean forceSourceMode) {
+          boolean forceSourceMode,
+          boolean waitForTargets) {
         this.filter = filter;
         this.sourceMode = sourceMode;
         this.targetMode = targetMode;
@@ -139,5 +146,6 @@ public JobDefinition(Predicate<CacheEntry> filter,
         this.pauseWhen = pauseWhen;
         this.stopWhen = stopWhen;
         this.forceSourceMode = forceSourceMode;
+        this.waitForTargets = waitForTargets;
     }
 }

modules/dcache/src/main/java/org/dcache/pool/migration/MigrationModule.java

@@ -537,6 +537,16 @@ public class MigrationCopyCommand implements Callable<String> {
               usage = "Enables the transfer of files from a disabled pool.")
         boolean forceSourceMode;
 
+        @Option(name = "target-deficit-mode", metaVar = "tdmode",
+                values = { "wait", "limit" },
+                category = "Transfer options",
+                usage = "Behaviour when requested replicas exceeds available targets:\n" +
+                        "wait:\n" +
+                        "    wait for new targets to become available.\n" +
+                        "limit:\n" +
+                        "    limit the number of replicas to that of the currently-available targets.\n")
+        String targetDeficitMode = "wait";
+
         @Argument(metaVar = "target",
               required = false,
               usage = "Required unless -target=pgroup is supplied, in which case we" +
@@ -838,7 +848,8 @@ public String call() throws IllegalArgumentException {
                         maintainAtime,
                         createLifetimePredicate(pauseWhen),
                         createLifetimePredicate(stopWhen),
-                        forceSourceMode);
+                        forceSourceMode,
+                        targetDeficitMode.equals("wait"));
 
             if (definition.targetMode.state == CacheEntryMode.State.DELETE
                   || definition.targetMode.state == CacheEntryMode.State.REMOVABLE) {

modules/dcache/src/main/java/org/dcache/pool/migration/TaskParameters.java

@@ -88,11 +88,16 @@ public class TaskParameters {
      */
     public final int replicas;
 
+    /**
+     * Whether to wait for targets to become available to satisfy number of replicas.
+     */
+    public final boolean waitForTargets;
+
     public TaskParameters(CellStub pool, CellStub pnfs, CellStub pinManager,
           ScheduledExecutorService executor,
           PoolSelectionStrategy selectionStrategy, RefreshablePoolList poolList, boolean isEager,
           boolean isMetaOnly, boolean computeChecksumOnUpdate, boolean forceSourceMode,
-          boolean maintainAtime, int replicas) {
+          boolean maintainAtime, int replicas, boolean waitForTargets) {
         this.pool = pool;
         this.pnfs = pnfs;
         this.pinManager = pinManager;
@@ -105,5 +110,6 @@ public TaskParameters(CellStub pool, CellStub pnfs, CellStub pinManager,
         this.forceSourceMode = forceSourceMode;
         this.maintainAtime = maintainAtime;
         this.replicas = replicas;
+        this.waitForTargets = waitForTargets;
     }
 }