From a77029a7a8885902edbc0034c15c2a609a1093ba Mon Sep 17 00:00:00 2001
Message-Id: <a77029a7a8885902edbc0034c15c2a609a1093ba@dist-git>
From: Peter Krempa <pkrempa@redhat.com>
Date: Thu, 23 Nov 2017 19:02:18 +0100
Subject: [PATCH] qemu: block: Add function to check if storage source allows
 concurrent access

Storage source format backing a shared device (e.g. running a cluster
filesystem) needs to support the sharing so that metadata are not
corrupted. Add a central function for checking this.

(cherry picked from commit 1fc3cd8731640aefc48bbd9fc489f21cb99c6f67)

 Conflicts:
	src/qemu/qemu_block.c: context of one of the blockdev-add saga
                               refactors not being backported

https://bugzilla.redhat.com/show_bug.cgi?id=1511480
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/qemu/qemu_block.c | 15 +++++++++++++++
 src/qemu/qemu_block.h |  3 +++
 2 files changed, 18 insertions(+)

diff --git a/src/qemu/qemu_block.c b/src/qemu/qemu_block.c
index 0761f89913..86fa565f39 100644
--- a/src/qemu/qemu_block.c
+++ b/src/qemu/qemu_block.c
@@ -390,6 +390,21 @@ qemuBlockGetNodeData(virJSONValuePtr data)
 }
 
 
+/**
+ * qemuBlockStorageSourceSupportsConcurrentAccess:
+ * @src: disk storage source
+ *
+ * Returns true if the given storage format supports concurrent access from two
+ * separate processes.
+ */
+bool
+qemuBlockStorageSourceSupportsConcurrentAccess(virStorageSourcePtr src)
+{
+    /* no need to check in backing chain since only RAW storage supports this */
+    return src->format == VIR_STORAGE_FILE_RAW;
+}
+
+
 /**
  * qemuBlockStorageSourceBuildJSONSocketAddress
  * @host: the virStorageNetHostDefPtr definition to build
diff --git a/src/qemu/qemu_block.h b/src/qemu/qemu_block.h
index f0a2c9aa7d..ebf3149ce8 100644
--- a/src/qemu/qemu_block.h
+++ b/src/qemu/qemu_block.h
@@ -53,6 +53,9 @@ qemuBlockNodeNamesDetect(virQEMUDriverPtr driver,
 virHashTablePtr
 qemuBlockGetNodeData(virJSONValuePtr data);
 
+bool
+qemuBlockStorageSourceSupportsConcurrentAccess(virStorageSourcePtr src);
+
 virJSONValuePtr
 qemuBlockStorageSourceGetBackendProps(virStorageSourcePtr src);
 
-- 
2.15.0