Add the virFileCache implementation for nbdkit capabilities to the qemu
driver. This allows us to determine whether nbdkit is installed and
which plugins are supported. it also has persistent caching and the
capabilities are re-queried whenever something changes.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
---
 src/qemu/qemu_conf.h   | 3 +++
 src/qemu/qemu_driver.c | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
index 4f610d86a1..a44985fb8b 100644
--- a/src/qemu/qemu_conf.h
+++ b/src/qemu/qemu_conf.h
@@ -318,6 +318,9 @@ struct _virQEMUDriver {
 
     /* Immutable pointer, self-locking APIs */
     virHashAtomic *migrationErrors;
+
+    /* Immutable pointer, self-locking APIs */
+    virFileCache *nbdkitCapsCache;
 };
 
 virQEMUDriverConfig *virQEMUDriverConfigNew(bool privileged,
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 5db42f0753..ad8428948b 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -845,6 +845,8 @@ qemuStateInitialize(bool privileged,
                                                            defsecmodel)))
         goto error;
 
+    qemu_driver->nbdkitCapsCache = qemuNbdkitCapsCacheNew(cfg->cacheDir);
+
     /* If hugetlbfs is present, then we need to create a sub-directory within
      * it, since we can't assume the root mount point has permissions that
      * will let our spawned QEMU instances use it. */
@@ -1078,6 +1080,7 @@ qemuStateCleanup(void)
     ebtablesContextFree(qemu_driver->ebtables);
     VIR_FREE(qemu_driver->qemuImgBinary);
     virObjectUnref(qemu_driver->domains);
+    virObjectUnref(qemu_driver->nbdkitCapsCache);
 
     if (qemu_driver->lockFD != -1)
         virPidFileRelease(qemu_driver->config->stateDir, "driver", qemu_driver->lockFD);
-- 
2.41.0