qmp: Add command 'blockdev-backup'

Similar to drive-backup, but this command uses a device id as target
instead of creating/opening an image file.

Also add blocker on target bs, since the target is also a named device
now.

Add check and report error for bs == target which became possible but is
an illegal case with introduction of blockdev-backup.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1418899027-8445-3-git-send-email-famz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/blockdev.c b/blockdev.c
index 5651a8e140..d6ccc5ebca 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2240,6 +2240,8 @@ void qmp_drive_backup(const char *device, const char *target,
     aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
+    /* Although backup_run has this check too, we need to use bs->drv below, so
+     * do an early check redundantly. */
     if (!bdrv_is_inserted(bs)) {
         error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
         goto out;
@@ -2256,6 +2258,7 @@ void qmp_drive_backup(const char *device, const char *target,
         }
     }
 
+    /* Early check to avoid creating target */
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
         goto out;
     }
@@ -2323,6 +2326,57 @@ BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
     return bdrv_named_nodes_list();
 }
 
+void qmp_blockdev_backup(const char *device, const char *target,
+                         enum MirrorSyncMode sync,
+                         bool has_speed, int64_t speed,
+                         bool has_on_source_error,
+                         BlockdevOnError on_source_error,
+                         bool has_on_target_error,
+                         BlockdevOnError on_target_error,
+                         Error **errp)
+{
+    BlockDriverState *bs;
+    BlockDriverState *target_bs;
+    Error *local_err = NULL;
+    AioContext *aio_context;
+
+    if (!has_speed) {
+        speed = 0;
+    }
+    if (!has_on_source_error) {
+        on_source_error = BLOCKDEV_ON_ERROR_REPORT;
+    }
+    if (!has_on_target_error) {
+        on_target_error = BLOCKDEV_ON_ERROR_REPORT;
+    }
+
+    bs = bdrv_find(device);
+    if (!bs) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+        return;
+    }
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    target_bs = bdrv_find(target);
+    if (!target_bs) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, target);
+        goto out;
+    }
+
+    bdrv_ref(target_bs);
+    bdrv_set_aio_context(target_bs, aio_context);
+    backup_start(bs, target_bs, speed, sync, on_source_error, on_target_error,
+                 block_job_cb, bs, &local_err);
+    if (local_err != NULL) {
+        bdrv_unref(target_bs);
+        error_propagate(errp, local_err);
+    }
+out:
+    aio_context_release(aio_context);
+}
+
 #define DEFAULT_MIRROR_BUF_SIZE   (10 << 20)
 
 void qmp_drive_mirror(const char *device, const char *target,