Merge branch 'stable-3.1' into stable-3.2v3.2.6

* stable-3.1:
  Fix replication to retry on lock errors

Change-Id: Icacd9095feaefd240803405c5b0a16cc0b3a9ed8

4 files changed, 58 insertions, 27 deletions

diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/Destination.java b/src/main/java/com/googlesource/gerrit/plugins/replication/Destination.java
index e2f9515..793bb5b 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/Destination.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/Destination.java
@@ -741,8 +741,8 @@ public class Destination {
     return config.getProjects();
   }
 
-  int getLockErrorMaxRetries() {
-    return config.getLockErrorMaxRetries();
+  int getUpdateRefErrorMaxRetries() {
+    return config.getUpdateRefErrorMaxRetries();
   }
 
   String getRemoteConfigName() {
diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/DestinationConfiguration.java b/src/main/java/com/googlesource/gerrit/plugins/replication/DestinationConfiguration.java
index 4b757ea..1b39374 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/DestinationConfiguration.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/DestinationConfiguration.java
@@ -31,7 +31,7 @@ public class DestinationConfiguration implements RemoteConfiguration {
   private final int rescheduleDelay;
   private final int retryDelay;
   private final int drainQueueAttempts;
-  private final int lockErrorMaxRetries;
+  private final int updateRefErrorMaxRetries;
   private final ImmutableList<String> adminUrls;
   private final int poolThreads;
   private final boolean createMissingRepos;
@@ -60,8 +60,11 @@ public class DestinationConfiguration implements RemoteConfiguration {
         Math.max(0, getInt(remoteConfig, cfg, "drainQueueAttempts", DEFAULT_DRAIN_QUEUE_ATTEMPTS));
     poolThreads = Math.max(0, getInt(remoteConfig, cfg, "threads", 1));
     authGroupNames = ImmutableList.copyOf(cfg.getStringList("remote", name, "authGroup"));
-    lockErrorMaxRetries = cfg.getInt("replication", "lockErrorMaxRetries", 0);
-
+    updateRefErrorMaxRetries =
+        cfg.getInt(
+            "replication",
+            "updateRefErrorMaxRetries",
+            cfg.getInt("replication", "lockErrorMaxRetries", 0));
     createMissingRepos = cfg.getBoolean("remote", name, "createMissingRepositories", true);
     replicatePermissions = cfg.getBoolean("remote", name, "replicatePermissions", true);
     replicateProjectDeletions = cfg.getBoolean("remote", name, "replicateProjectDeletions", false);
@@ -106,8 +109,8 @@ public class DestinationConfiguration implements RemoteConfiguration {
     return poolThreads;
   }
 
-  public int getLockErrorMaxRetries() {
-    return lockErrorMaxRetries;
+  public int getUpdateRefErrorMaxRetries() {
+    return updateRefErrorMaxRetries;
   }
 
   @Override
diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java b/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
index 3c34fb6..bdef2fa 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
@@ -91,6 +91,17 @@ class PushOne implements ProjectRunnable, CanceledWhileRunning, UriUpdates {
   static final String ALL_REFS = "..all..";
   static final String ID_KEY = "pushOneId";
 
+  // The string here needs to match the one returned by Git(versions prior to 2014) server.
+  // See:
+  // https://github.com/git/git/blob/b4d75ac1d152bbab44b0777a4cc0c48db75f6024/builtin/receive-pack.c#L587
+  // https://github.com/eclipse/jgit/blob/8774f541904ca9afba1786b4da14c1aedf4dda78/org.eclipse.jgit/src/org/eclipse/jgit/transport/ReceivePack.java#L1859
+  static final String LOCK_FAILURE = "failed to lock";
+
+  // The string here needs to match the one returned by Git server.
+  // See:
+  // https://github.com/git/git/blob/e67fbf927dfdf13d0b21dc6ea15dc3c7ef448ea0/builtin/receive-pack.c#L1611
+  static final String UPDATE_REF_FAILURE = "failed to update ref";
+
   interface Factory {
     PushOne create(Project.NameKey d, URIish u);
   }
@@ -114,8 +125,8 @@ class PushOne implements ProjectRunnable, CanceledWhileRunning, UriUpdates {
   private final int maxRetries;
   private boolean canceled;
   private final ListMultimap<String, ReplicationState> stateMap = LinkedListMultimap.create();
-  private final int maxLockRetries;
-  private int lockRetryCount;
+  private final int maxUpdateRefRetries;
+  private int updateRefRetryCount;
   private final int id;
   private final long createdAt;
   private final ReplicationMetrics metrics;
@@ -151,8 +162,8 @@ class PushOne implements ProjectRunnable, CanceledWhileRunning, UriUpdates {
     threadScoper = ts;
     projectName = d;
     uri = u;
-    lockRetryCount = 0;
-    maxLockRetries = pool.getLockErrorMaxRetries();
+    updateRefRetryCount = 0;
+    maxUpdateRefRetries = pool.getUpdateRefErrorMaxRetries();
     id = ig.next();
     stateLog = sl;
     createdAt = System.nanoTime();
@@ -391,12 +402,12 @@ class PushOne implements ProjectRunnable, CanceledWhileRunning, UriUpdates {
       Throwable cause = e.getCause();
       if (cause instanceof JSchException && cause.getMessage().startsWith("UnknownHostKey:")) {
         repLog.atSevere().log("Cannot replicate to %s: %s", uri, cause.getMessage());
-      } else if (e instanceof LockFailureException) {
-        lockRetryCount++;
-        repLog.atSevere().log("Cannot replicate to %s due to lock failure", uri);
+      } else if (e instanceof UpdateRefFailureException) {
+        updateRefRetryCount++;
+        repLog.atSevere().log("Cannot replicate to %s due to a lock or write ref failure", uri);
 
         // The remote push operation should be retried.
-        if (lockRetryCount <= maxLockRetries) {
+        if (updateRefRetryCount <= maxUpdateRefRetries) {
           if (canceledWhileRunning.get()) {
             logCanceledWhileRunningException(e);
           } else {
@@ -404,7 +415,8 @@ class PushOne implements ProjectRunnable, CanceledWhileRunning, UriUpdates {
           }
         } else {
           repLog.atSevere().log(
-              "Giving up after %d lock failures during replication to %s", lockRetryCount, uri);
+              "Giving up after %d '%s' failures during replication to %s",
+              updateRefRetryCount, e.getMessage(), uri);
         }
       } else {
         if (canceledWhileRunning.get()) {
@@ -676,7 +688,8 @@ class PushOne implements ProjectRunnable, CanceledWhileRunning, UriUpdates {
     cmds.add(new RemoteRefUpdate(git, (Ref) null, dst, force, null, null));
   }
 
-  private void updateStates(Collection<RemoteRefUpdate> refUpdates) throws LockFailureException {
+  private void updateStates(Collection<RemoteRefUpdate> refUpdates)
+      throws UpdateRefFailureException {
     Set<String> doneRefs = new HashSet<>();
     boolean anyRefFailed = false;
     RemoteRefUpdate.Status lastRefStatusError = RemoteRefUpdate.Status.OK;
@@ -720,8 +733,9 @@ class PushOne implements ProjectRunnable, CanceledWhileRunning, UriUpdates {
                         + " of destination repository.",
                     u.getRemoteName(), uri),
                 logStatesArray);
-          } else if ("failed to lock".equals(u.getMessage())) {
-            throw new LockFailureException(uri, u.getMessage());
+          } else if (LOCK_FAILURE.equals(u.getMessage())
+              || UPDATE_REF_FAILURE.equals(u.getMessage())) {
+            throw new UpdateRefFailureException(uri, u.getMessage());
           } else {
             stateLog.error(
                 String.format(
@@ -760,10 +774,10 @@ class PushOne implements ProjectRunnable, CanceledWhileRunning, UriUpdates {
     stateMap.clear();
   }
 
-  public static class LockFailureException extends TransportException {
+  public static class UpdateRefFailureException extends TransportException {
     private static final long serialVersionUID = 1L;
 
-    LockFailureException(URIish uri, String message) {
+    UpdateRefFailureException(URIish uri, String message) {
       super(uri, message);
     }
   }
diff --git a/src/main/resources/Documentation/config.md b/src/main/resources/Documentation/config.md
index fc3352d..6a2cf26 100644
--- a/src/main/resources/Documentation/config.md
+++ b/src/main/resources/Documentation/config.md
@@ -108,19 +108,23 @@ replication.distributionInterval
 	value for this is approximately the smallest remote.NAME.replicationDelay
 	divided by 5.
 
-replication.lockErrorMaxRetries
-:	Number of times to retry a replication operation if a lock
-	error is detected.
+<a name="replication.updateRefErrorMaxRetries">replication.updateRefErrorMaxRetries</a>
+:	Number of times to retry a replication operation if an update
+	ref error is detected.
 
 	If two or more replication operations (to the same GIT and Ref)
 	are scheduled at approximately the same time (and end up on different
 	replication threads), there is a large probability that the last
-	push to complete will fail with a remote "failure to lock" error.
+	push to complete will fail with a remote "failed to update ref" error.
+	This error may also occur due to a transient issue like file system
+	being full which was previously returned as "failed to write" by git.
+
 	This option allows Gerrit to retry the replication push when the
-	"failure to lock" error is detected.
+	"failed to update ref" error is detected. Also retry when the error
+	"failed to lock" is detected as that is the legacy string used by git.
 
 	A good value would be 3 retries or less, depending on how often
-	you see lockError collisions in your server logs. A too highly set
+	you see updateRefError collisions in your server logs. A too highly set
 	value risks keeping around the replication operations in the queue
 	for a long time, and the number of items in the queue will increase
 	with time.
@@ -135,6 +139,16 @@ replication.lockErrorMaxRetries
 
 	Default: 0 (disabled, i.e. never retry)
 
+replication.lockErrorMaxRetries
+:	Refer to the [replication.updateRefErrorMaxRetries][4] section.
+
+	If both `lockErrorMaxRetries` and `updateRefErrorMaxRetries` are
+	configured, then `updateRefErrorMaxRetries` takes precedence.
+
+	Default: 0 (disabled, i.e. never retry)
+
+[4]: #replication.updateRefErrorMaxRetries
+
 replication.maxRetries
 :	Maximum number of times to retry a push operation that previously
 	failed.