[PATCH v2 2/4] block/export: add blk_by_export_id()

[Vladimir Sementsov-Ogievskiy <vsementsov@xxxxxxxxxxxxx>]

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@xxxxxxxxxxxxx>
---
 include/sysemu/block-backend.h |  1 +
 block/export/export.c          | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 904d70f49c..250c7465a5 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -124,6 +124,7 @@ DeviceState *blk_get_attached_dev(BlockBackend *blk);
 char *blk_get_attached_dev_id(BlockBackend *blk);
 BlockBackend *blk_by_dev(void *dev);
 BlockBackend *blk_by_qdev_id(const char *id, Error **errp);
+BlockBackend *blk_by_export_id(const char *id, Error **errp);
 void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops, void *opaque);
 int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
                                int64_t bytes, QEMUIOVector *qiov,
diff --git a/block/export/export.c b/block/export/export.c
index 6d3b9964c8..613b5bc1d5 100644
--- a/block/export/export.c
+++ b/block/export/export.c
@@ -362,3 +362,21 @@ BlockExportInfoList *qmp_query_block_exports(Error **errp)
 
     return head;
 }
+
+BlockBackend *blk_by_export_id(const char *id, Error **errp)
+{
+    BlockExport *exp;
+
+    exp = blk_exp_find(id);
+    if (exp == NULL) {
+        error_setg(errp, "Export '%s' not found", id);
+        return NULL;
+    }
+
+    if (!exp->blk) {
+        error_setg(errp, "Export '%s' is empty", id);
+        return NULL;
+    }
+
+    return exp->blk;
+}
-- 
2.31.1