[libvirt] [PATCH] Add support for disks backed by plain files in LXC
From: "Daniel P. Berrange" <berrange(a)redhat.com>
By using a loopback device, disks backed by plain files can
be made available to LXC containers. We make no attempt to
auto-detect format if <driver type="raw"/> is not set,
instead we unconditionally treat that as meaning raw. This
is to avoid the security issues inherant with format
auto-detection
Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com>
---
src/lxc/lxc_controller.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 65 insertions(+), 2 deletions(-)
diff --git a/src/lxc/lxc_controller.c b/src/lxc/lxc_controller.c
index a7e715e..176e1be 100644
--- a/src/lxc/lxc_controller.c
+++ b/src/lxc/lxc_controller.c
@@ -356,7 +356,7 @@ static int virLXCControllerValidateConsoles(virLXCControllerPtr ctrl)
}
-static int virLXCControllerSetupLoopDevice(virDomainFSDefPtr fs)
+static int virLXCControllerSetupLoopDeviceFS(virDomainFSDefPtr fs)
{
int lofd;
char *loname = NULL;
@@ -377,6 +377,27 @@ static int virLXCControllerSetupLoopDevice(virDomainFSDefPtr fs)
}
+static int virLXCControllerSetupLoopDeviceDisk(virDomainDiskDefPtr disk)
+{
+ int lofd;
+ char *loname = NULL;
+
+ if ((lofd = virFileLoopDeviceAssociate(disk->src, &loname)) < 0)
+ return -1;
+
+ /*
+ * We now change it into a block device type, so that
+ * the rest of container setup 'just works'
+ */
+ disk->type = VIR_DOMAIN_DISK_TYPE_BLOCK;
+ VIR_FREE(disk->src);
+ disk->src = loname;
+ loname = NULL;
+
+ return lofd;
+}
+
+
static int virLXCControllerSetupLoopDevices(virLXCControllerPtr ctrl)
{
size_t i;
@@ -389,7 +410,7 @@ static int virLXCControllerSetupLoopDevices(virLXCControllerPtr ctrl)
if (fs->type != VIR_DOMAIN_FS_TYPE_FILE)
continue;
- fd = virLXCControllerSetupLoopDevice(fs);
+ fd = virLXCControllerSetupLoopDeviceFS(fs);
if (fd < 0)
goto cleanup;
@@ -402,6 +423,48 @@ static int virLXCControllerSetupLoopDevices(virLXCControllerPtr
ctrl)
ctrl->loopDevFds[ctrl->nloopDevs - 1] = fd;
}
+ for (i = 0 ; i < ctrl->def->ndisks ; i++) {
+ virDomainDiskDefPtr disk = ctrl->def->disks[i];
+ int fd;
+
+ if (disk->type != VIR_DOMAIN_DISK_TYPE_FILE)
+ continue;
+
+ switch (disk->format) {
+ /* We treat 'none' as meaning 'raw' since we
+ * don't want to go into the auto-probing
+ * business for security reasons
+ */
+ case VIR_STORAGE_FILE_RAW:
+ case VIR_STORAGE_FILE_NONE:
+ if (disk->driverName &&
+ STRNEQ(disk->driverName, "loop")) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("disk driver %s is not supported"),
+ disk->driverName);
+ goto cleanup;
+ }
+
+ fd = virLXCControllerSetupLoopDeviceDisk(disk);
+ if (fd < 0)
+ goto cleanup;
+
+ default:
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("disk format %s is not supported"),
+ virStorageFileFormatTypeToString(disk->format));
+ goto cleanup;
+ }
+
+ VIR_DEBUG("Saving loop fd %d", fd);
+ if (VIR_EXPAND_N(ctrl->loopDevFds, ctrl->nloopDevs, 1) < 0) {
+ VIR_FORCE_CLOSE(fd);
+ virReportOOMError();
+ goto cleanup;
+ }
+ ctrl->loopDevFds[ctrl->nloopDevs - 1] = fd;
+ }
+
VIR_DEBUG("Setup all loop devices");
ret = 0;
--
1.7.11.7