qemu: domain: Reject shared disk access if backing format does not support it

Disk sharing between two VMs may corrupt the images if the format driver
does not support it. Check that the user declared use of a supported
storage format when they want to share the disk.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1511480

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index bd96b26172594ec98aadc343e154b9c128517e4d..d068b36f4eaf3b3a753c80c945683a67038612c9 100644 (file)
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -25,6 +25,7 @@
 
 #include "qemu_domain.h"
 #include "qemu_alias.h"
+#include "qemu_block.h"
 #include "qemu_cgroup.h"
 #include "qemu_command.h"
 #include "qemu_process.h"
@@ -3724,6 +3725,29 @@ qemuDomainDeviceDefValidateVideo(const virDomainVideoDef *video)
 }
 
 
+static int
+qemuDomainDeviceDefValidateDisk(const virDomainDiskDef *disk)
+{
+    if (disk->src->shared && !disk->src->readonly) {
+        if (disk->src->format <= VIR_STORAGE_FILE_AUTO) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("shared access for disk '%s' requires use of "
+                             "explicitly specified disk format"), disk->dst);
+            return -1;
+        }
+
+        if (!qemuBlockStorageSourceSupportsConcurrentAccess(disk->src)) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("shared access for disk '%s' requires use of "
+                             "supported storage format"), disk->dst);
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+
 static int
 qemuDomainDeviceDefValidate(const virDomainDeviceDef *dev,
                             const virDomainDef *def,
@@ -3765,6 +3789,9 @@ qemuDomainDeviceDefValidate(const virDomainDeviceDef *dev,
         break;
 
     case VIR_DOMAIN_DEVICE_DISK:
+        ret = qemuDomainDeviceDefValidateDisk(dev->data.disk);
+        break;
+
     case VIR_DOMAIN_DEVICE_LEASE:
     case VIR_DOMAIN_DEVICE_FS:
     case VIR_DOMAIN_DEVICE_INPUT:

diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared-qcow.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared-qcow.xml
new file mode 100644 (file)
index 0000000..ca88a94
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared-qcow.xml
@@ -0,0 +1,28 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-i686</emulator>
+    <disk type='block' device='disk'>
+      <driver name='qemu' type='qcow2'/>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <shareable/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
+  </devices>
+</domain>

diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared.args b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared.args
index e9c7bb9deb379ede2e51f8f907c63a8b23c5a535..f449ddca727990dd5a281392df9f4fc7b9ac5f52 100644 (file)
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared.args
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared.args
@@ -19,7 +19,7 @@ server,nowait \
 -no-acpi \
 -boot c \
 -usb \
--drive file=/dev/HostVG/QEMUGuest1,format=qcow2,if=none,id=drive-ide0-0-0,\
+-drive file=/dev/HostVG/QEMUGuest1,format=raw,if=none,id=drive-ide0-0-0,\
 serial=XYZXYZXYZYXXYZYZYXYZY,cache=none \
 -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 \
 -drive file=/dev/HostVG/QEMUGuest2,format=raw,if=none,id=drive-ide0-1-0,\

diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared.xml
index 9f747237836bf1123134b6d7b1506cc7fdb0e152..677c2b0b7d6d089ecf89f5c3e80bb8dded501a01 100644 (file)
--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-shared.xml
@@ -15,7 +15,7 @@
   <devices>
     <emulator>/usr/bin/qemu-system-i686</emulator>
     <disk type='block' device='disk'>
-      <driver name='qemu' type='qcow2'/>
+      <driver name='qemu' type='raw'/>
       <source dev='/dev/HostVG/QEMUGuest1'/>
       <target dev='hda' bus='ide'/>
       <shareable/>

diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index 66af2d3285ac163e003bfef2cbce0a3bb1052a88..cb8a964d270b2bad6d3d93ef4cf7d8f1040017a4 100644 (file)
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -908,6 +908,7 @@ mymain(void)
             QEMU_CAPS_DRIVE_BOOT);
     DO_TEST("disk-drive-shared",
             QEMU_CAPS_DRIVE_SERIAL);
+    DO_TEST_PARSE_ERROR("disk-drive-shared-qcow", NONE);
     DO_TEST("disk-drive-error-policy-stop",
             QEMU_CAPS_MONITOR_JSON);
     DO_TEST("disk-drive-error-policy-enospace",