block/mirror: Add copy mode QAPI interface

This patch allows the user to specify whether to use active or only
background mode for mirror block jobs.  Currently, this setting will
remain constant for the duration of the entire block job.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20180613181823.13618-14-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

4 files changed, 27 insertions, 9 deletions

diff --git a/block/mirror.c b/block/mirror.c
index 99b9b92c30..61bd9f3cf1 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1473,7 +1473,7 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs,
                              const BlockJobDriver *driver,
                              bool is_none_mode, BlockDriverState *base,
                              bool auto_complete, const char *filter_node_name,
-                             bool is_mirror,
+                             bool is_mirror, MirrorCopyMode copy_mode,
                              Error **errp)
 {
     MirrorBlockJob *s;
@@ -1581,7 +1581,7 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs,
     s->on_target_error = on_target_error;
     s->is_none_mode = is_none_mode;
     s->backing_mode = backing_mode;
-    s->copy_mode = MIRROR_COPY_MODE_BACKGROUND;
+    s->copy_mode = copy_mode;
     s->base = base;
     s->granularity = granularity;
     s->buf_size = ROUND_UP(buf_size, granularity);
@@ -1648,7 +1648,8 @@ void mirror_start(const char *job_id, BlockDriverState *bs,
                   MirrorSyncMode mode, BlockMirrorBackingMode backing_mode,
                   BlockdevOnError on_source_error,
                   BlockdevOnError on_target_error,
-                  bool unmap, const char *filter_node_name, Error **errp)
+                  bool unmap, const char *filter_node_name,
+                  MirrorCopyMode copy_mode, Error **errp)
 {
     bool is_none_mode;
     BlockDriverState *base;
@@ -1663,7 +1664,7 @@ void mirror_start(const char *job_id, BlockDriverState *bs,
                      speed, granularity, buf_size, backing_mode,
                      on_source_error, on_target_error, unmap, NULL, NULL,
                      &mirror_job_driver, is_none_mode, base, false,
-                     filter_node_name, true, errp);
+                     filter_node_name, true, copy_mode, errp);
 }
 
 void commit_active_start(const char *job_id, BlockDriverState *bs,
@@ -1686,7 +1687,8 @@ void commit_active_start(const char *job_id, BlockDriverState *bs,
                      MIRROR_LEAVE_BACKING_CHAIN,
                      on_error, on_error, true, cb, opaque,
                      &commit_active_job_driver, false, base, auto_complete,
-                     filter_node_name, false, &local_err);
+                     filter_node_name, false, MIRROR_COPY_MODE_BACKGROUND,
+                     &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         goto error_restore_flags;
diff --git a/blockdev.c b/blockdev.c
index 7f65cd7497..58d7570932 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3586,6 +3586,7 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs,
                                    bool has_unmap, bool unmap,
                                    bool has_filter_node_name,
                                    const char *filter_node_name,
+                                   bool has_copy_mode, MirrorCopyMode copy_mode,
                                    Error **errp)
 {
 
@@ -3610,6 +3611,9 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs,
     if (!has_filter_node_name) {
         filter_node_name = NULL;
     }
+    if (!has_copy_mode) {
+        copy_mode = MIRROR_COPY_MODE_BACKGROUND;
+    }
 
     if (granularity != 0 && (granularity < 512 || granularity > 1048576 * 64)) {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "granularity",
@@ -3640,7 +3644,7 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs,
                  has_replaces ? replaces : NULL,
                  speed, granularity, buf_size, sync, backing_mode,
                  on_source_error, on_target_error, unmap, filter_node_name,
-                 errp);
+                 copy_mode, errp);
 }
 
 void qmp_drive_mirror(DriveMirror *arg, Error **errp)
@@ -3786,6 +3790,7 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
                            arg->has_on_target_error, arg->on_target_error,
                            arg->has_unmap, arg->unmap,
                            false, NULL,
+                           arg->has_copy_mode, arg->copy_mode,
                            &local_err);
     bdrv_unref(target_bs);
     error_propagate(errp, local_err);
@@ -3806,6 +3811,7 @@ void qmp_blockdev_mirror(bool has_job_id, const char *job_id,
                          BlockdevOnError on_target_error,
                          bool has_filter_node_name,
                          const char *filter_node_name,
+                         bool has_copy_mode, MirrorCopyMode copy_mode,
                          Error **errp)
 {
     BlockDriverState *bs;
@@ -3838,6 +3844,7 @@ void qmp_blockdev_mirror(bool has_job_id, const char *job_id,
                            has_on_target_error, on_target_error,
                            true, true,
                            has_filter_node_name, filter_node_name,
+                           has_copy_mode, copy_mode,
                            &local_err);
     error_propagate(errp, local_err);
 
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 7cd7eed83b..74646ed722 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -1031,6 +1031,7 @@ void commit_active_start(const char *job_id, BlockDriverState *bs,
  * @filter_node_name: The node name that should be assigned to the filter
  * driver that the mirror job inserts into the graph above @bs. NULL means that
  * a node name should be autogenerated.
+ * @copy_mode: When to trigger writes to the target.
  * @errp: Error object.
  *
  * Start a mirroring operation on @bs.  Clusters that are allocated
@@ -1044,7 +1045,8 @@ void mirror_start(const char *job_id, BlockDriverState *bs,
                   MirrorSyncMode mode, BlockMirrorBackingMode backing_mode,
                   BlockdevOnError on_source_error,
                   BlockdevOnError on_target_error,
-                  bool unmap, const char *filter_node_name, Error **errp);
+                  bool unmap, const char *filter_node_name,
+                  MirrorCopyMode copy_mode, Error **errp);
 
 /*
  * backup_job_create:
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 96f8da1322..cc3ede0630 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1710,6 +1710,9 @@
 #         written. Both will result in identical contents.
 #         Default is true. (Since 2.4)
 #
+# @copy-mode: when to copy data to the destination; defaults to 'background'
+#             (Since: 3.0)
+#
 # Since: 1.3
 ##
 { 'struct': 'DriveMirror',
@@ -1719,7 +1722,7 @@
             '*speed': 'int', '*granularity': 'uint32',
             '*buf-size': 'int', '*on-source-error': 'BlockdevOnError',
             '*on-target-error': 'BlockdevOnError',
-            '*unmap': 'bool' } }
+            '*unmap': 'bool', '*copy-mode': 'MirrorCopyMode' } }
 
 ##
 # @BlockDirtyBitmap:
@@ -1982,6 +1985,9 @@
 #                    above @device. If this option is not given, a node name is
 #                    autogenerated. (Since: 2.9)
 #
+# @copy-mode: when to copy data to the destination; defaults to 'background'
+#             (Since: 3.0)
+#
 # Returns: nothing on success.
 #
 # Since: 2.6
@@ -2002,7 +2008,8 @@
             '*speed': 'int', '*granularity': 'uint32',
             '*buf-size': 'int', '*on-source-error': 'BlockdevOnError',
             '*on-target-error': 'BlockdevOnError',
-            '*filter-node-name': 'str' } }
+            '*filter-node-name': 'str',
+            '*copy-mode': 'MirrorCopyMode' } }
 
 ##
 # @block_set_io_throttle: