[Qemu-devel] [PATCH v6 03/12] migration: avoid concurrent invoke channel_close by different threads

[Lidong Chen <jemmy858585@gmail.com>]

From: Lidong Chen <jemmy858585@gmail.com>

The channel_close maybe invoked by different threads. For example, source
qemu invokes qemu_fclose in main thread, migration thread and return path
thread. Destination qemu invokes qemu_fclose in main thread, listen thread
and COLO incoming thread.

Signed-off-by: Lidong Chen <lidongchen@tencent.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
---
 migration/migration.c | 2 ++
 migration/migration.h | 7 +++++++
 migration/qemu-file.c | 6 ++++--
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index b7d9854..a3a0756 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -3200,6 +3200,7 @@ static void migration_instance_finalize(Object *obj)
     qemu_sem_destroy(&ms->postcopy_pause_sem);
     qemu_sem_destroy(&ms->postcopy_pause_rp_sem);
     qemu_sem_destroy(&ms->rp_state.rp_sem);
+    qemu_mutex_destroy(&ms->qemu_file_close_lock);
     error_free(ms->error);
 }
 
@@ -3236,6 +3237,7 @@ static void migration_instance_init(Object *obj)
     qemu_sem_init(&ms->rp_state.rp_sem, 0);
     qemu_sem_init(&ms->rate_limit_sem, 0);
     qemu_mutex_init(&ms->qemu_file_lock);
+    qemu_mutex_init(&ms->qemu_file_close_lock);
 }
 
 /*
diff --git a/migration/migration.h b/migration/migration.h
index 64a7b33..a50c2de 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -122,6 +122,13 @@ struct MigrationState
     QemuMutex qemu_file_lock;
 
     /*
+     * The to_src_file and from_dst_file point to one QIOChannelRDMA,
+     * And qemu_fclose maybe invoked by different threads. use this lock
+     * to avoid concurrent invoke channel_close by different threads.
+     */
+    QemuMutex qemu_file_close_lock;
+
+    /*
      * Used to allow urgent requests to override rate limiting.
      */
     QemuSemaphore rate_limit_sem;
diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index 977b9ae..74c48e0 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -323,12 +323,14 @@ void qemu_update_position(QEMUFile *f, size_t size)
  */
 int qemu_fclose(QEMUFile *f)
 {
-    int ret;
+    int ret, ret2;
     qemu_fflush(f);
     ret = qemu_file_get_error(f);
 
     if (f->ops->close) {
-        int ret2 = f->ops->close(f->opaque);
+        qemu_mutex_lock(&migrate_get_current()->qemu_file_close_lock);
+        ret2 = f->ops->close(f->opaque);
+        qemu_mutex_unlock(&migrate_get_current()->qemu_file_close_lock);
         if (ret >= 0) {
             ret = ret2;
         }
-- 
1.8.3.1