[lxc-devel] [lxd/master] migration: fix btrfs live migration

[brauner on Github]

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From 795d74cafced1b4c39c6623d197754ef9d42a83c Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner at ubuntu.com>
Date: Wed, 25 Apr 2018 16:09:42 +0200
Subject: [PATCH] migration: fix btrfs live migration

Closes #4475.

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>
---
 lxd/container_lxc.go     |  5 +++++
 lxd/migrate_container.go |  4 ++++
 lxd/storage_btrfs.go     | 10 ++++++++--
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/lxd/container_lxc.go b/lxd/container_lxc.go
index 63e137031..640dbc552 100644
--- a/lxd/container_lxc.go
+++ b/lxd/container_lxc.go
@@ -5104,6 +5104,11 @@ func (c *containerLXC) Migrate(args *CriuMigrationArgs) error {
 			opts.PredumpDir = fmt.Sprintf("../%s", args.preDumpDir)
 		}
 
+		if !c.IsRunning() {
+			// otherwise the migration will needlessly fail
+			args.stop = false
+		}
+
 		migrateErr = c.c.Migrate(args.cmd, opts)
 	}
 
diff --git a/lxd/migrate_container.go b/lxd/migrate_container.go
index 9e1bd8aca..2d583fc28 100644
--- a/lxd/migrate_container.go
+++ b/lxd/migrate_container.go
@@ -993,6 +993,10 @@ func (c *migrationSink) Do(migrateOp *operation) error {
 	for {
 		select {
 		case err = <-restore:
+			if err != nil {
+				disconnector()
+				return err
+			}
 			controller(err)
 			return err
 		case msg, ok := <-source:
diff --git a/lxd/storage_btrfs.go b/lxd/storage_btrfs.go
index 6c2e02f4f..67ef92d95 100644
--- a/lxd/storage_btrfs.go
+++ b/lxd/storage_btrfs.go
@@ -2097,8 +2097,6 @@ func (s *storageBtrfs) MigrationSink(live bool, container container, snapshots [
 			return err
 		}
 
-		defer os.RemoveAll(btrfsPath)
-
 		err = btrfsSubVolumesDelete(receivedSnapshot)
 		if err != nil {
 			logger.Errorf("Failed to delete BTRFS subvolume \"%s\": %s.", btrfsPath, err)
@@ -2184,6 +2182,7 @@ func (s *storageBtrfs) MigrationSink(live bool, container container, snapshots [
 
 			wrapper := StorageProgressWriter(op, "fs_progress", *snap.Name)
 			err = btrfsRecv(*(snap.Name), tmpSnapshotMntPoint, snapshotMntPoint, true, wrapper)
+			os.RemoveAll(tmpSnapshotMntPoint)
 			if err != nil {
 				return err
 			}
@@ -2215,6 +2214,13 @@ func (s *storageBtrfs) MigrationSink(live bool, container container, snapshots [
 		return err
 	}
 
+	if live {
+		err = btrfsRecv("", tmpContainerMntPoint, containerMntPoint, false, wrapper)
+		if err != nil {
+			return err
+		}
+	}
+
 	return nil
 }