qemu: Reject updating unsupported disk information

If one calls update-device with information that is not updatable,
libvirt reports success even though no data were updated.  The example
used in the bug linked below uses updating device with <boot order='2'/>
which, in my opinion, is a valid thing to request from user's
perspective.  Mainly since we properly error out if user wants to update
such data on a network device for example.

And since there are many things that might happen (update-device on disk
basically knows just how to change removable media), check for what's
changing and moreover, since the function might be usable in other
drivers (updating only disk path is a valid possibility) let's abstract
it for any two disks.

We can't possibly check for everything since for many fields our code
does not properly differentiate between default and unspecified values.
Even though this could be changed, I don't feel like it's worth the
complexity so it's not the aim of this patch.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1007228

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 5a9a88d633b88298d2827d09ea65fb7be5f9e489..73ac5374fd8ba519328c95b27c837a8f3c542300 100644 (file)
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -5690,6 +5690,134 @@ virDomainDiskFindByBusAndDst(virDomainDefPtr def,
     return NULL;
 }
 
+
+/*
+ * Makes sure the @disk differs from @orig_disk only by the source
+ * path and nothing else.  Fields that are being checked and the
+ * information whether they are nullable (may not be specified) or is
+ * taken from the virDomainDiskDefFormat() code.
+ */
+bool
+virDomainDiskDiffersSourceOnly(virDomainDiskDefPtr disk,
+                               virDomainDiskDefPtr orig_disk)
+{
+#define CHECK_EQ(field, field_name, nullable)                           \
+    do {                                                                \
+        if (nullable && !disk->field)                                   \
+            break;                                                      \
+        if (disk->field != orig_disk->field) {                          \
+            virReportError(VIR_ERR_OPERATION_UNSUPPORTED,               \
+                           _("cannot modify field '%s' of the disk"),   \
+                           field_name);                                 \
+            return false;                                               \
+        }                                                               \
+    } while (0)
+
+    CHECK_EQ(device, "device", false);
+    CHECK_EQ(cachemode, "cache", true);
+    CHECK_EQ(error_policy, "error_policy", true);
+    CHECK_EQ(rerror_policy, "rerror_policy", true);
+    CHECK_EQ(iomode, "io", true);
+    CHECK_EQ(ioeventfd, "ioeventfd", true);
+    CHECK_EQ(event_idx, "event_idx", true);
+    CHECK_EQ(copy_on_read, "copy_on_read", true);
+    CHECK_EQ(discard, "discard", true);
+    CHECK_EQ(iothread, "iothread", true);
+
+    if (disk->geometry.cylinders &&
+        disk->geometry.heads &&
+        disk->geometry.sectors) {
+        CHECK_EQ(geometry.cylinders, "geometry cylinders", false);
+        CHECK_EQ(geometry.heads, "geometry heads", false);
+        CHECK_EQ(geometry.sectors, "geometry sectors", false);
+        CHECK_EQ(geometry.trans, "BIOS-translation-modus", true);
+    }
+
+    CHECK_EQ(blockio.logical_block_size,
+             "blockio logical_block_size", false);
+    CHECK_EQ(blockio.physical_block_size,
+             "blockio physical_block_size", false);
+
+    if (disk->bus == VIR_DOMAIN_DISK_BUS_USB)
+        CHECK_EQ(removable, "removable", true);
+
+    CHECK_EQ(blkdeviotune.total_bytes_sec,
+             "blkdeviotune total_bytes_sec",
+             true);
+    CHECK_EQ(blkdeviotune.read_bytes_sec,
+             "blkdeviotune read_bytes_sec",
+             true);
+    CHECK_EQ(blkdeviotune.write_bytes_sec,
+             "blkdeviotune write_bytes_sec",
+             true);
+    CHECK_EQ(blkdeviotune.total_iops_sec,
+             "blkdeviotune total_iops_sec",
+             true);
+    CHECK_EQ(blkdeviotune.read_iops_sec,
+             "blkdeviotune read_iops_sec",
+             true);
+    CHECK_EQ(blkdeviotune.write_iops_sec,
+             "blkdeviotune write_iops_sec",
+             true);
+    CHECK_EQ(blkdeviotune.total_bytes_sec_max,
+             "blkdeviotune total_bytes_sec_max",
+             true);
+    CHECK_EQ(blkdeviotune.read_bytes_sec_max,
+             "blkdeviotune read_bytes_sec_max",
+             true);
+    CHECK_EQ(blkdeviotune.write_bytes_sec_max,
+             "blkdeviotune write_bytes_sec_max",
+             true);
+    CHECK_EQ(blkdeviotune.total_iops_sec_max,
+             "blkdeviotune total_iops_sec_max",
+             true);
+    CHECK_EQ(blkdeviotune.read_iops_sec_max,
+             "blkdeviotune read_iops_sec_max",
+             true);
+    CHECK_EQ(blkdeviotune.write_iops_sec_max,
+             "blkdeviotune write_iops_sec_max",
+             true);
+    CHECK_EQ(blkdeviotune.size_iops_sec,
+             "blkdeviotune size_iops_sec",
+             true);
+
+    CHECK_EQ(transient, "transient", true);
+
+    if (disk->serial && STRNEQ(disk->serial, orig_disk->serial)) {
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
+                       _("cannot modify field '%s' of the disk"),
+                       "serial");
+        return false;
+    }
+
+    if (disk->wwn && STRNEQ(disk->wwn, orig_disk->wwn)) {
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
+                       _("cannot modify field '%s' of the disk"),
+                       "wwn");
+        return false;
+    }
+
+    if (disk->vendor && STRNEQ(disk->vendor, orig_disk->vendor)) {
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
+                       _("cannot modify field '%s' of the disk"),
+                       "vendor");
+        return false;
+    }
+
+    if (disk->product && STRNEQ(disk->product, orig_disk->product)) {
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
+                       _("cannot modify field '%s' of the disk"),
+                       "product");
+        return false;
+    }
+
+    CHECK_EQ(info.bootIndex, "boot order", true);
+
+#undef CHECK_EQ
+
+    return true;
+}
+
 int
 virDomainDiskDefAssignAddress(virDomainXMLOptionPtr xmlopt,
                               virDomainDiskDefPtr def)

diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 50750c1dfa14400b99ae05a524271d124ecd6869..0fe6b1a47c8fdf67b55171ffdb581d20c5075d7e 100644 (file)
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -2474,6 +2474,8 @@ int virDomainDeviceFindControllerModel(virDomainDefPtr def,
 virDomainDiskDefPtr virDomainDiskFindByBusAndDst(virDomainDefPtr def,
                                                  int bus,
                                                  char *dst);
+bool virDomainDiskDiffersSourceOnly(virDomainDiskDefPtr disk,
+                                    virDomainDiskDefPtr orig_disk);
 void virDomainControllerDefFree(virDomainControllerDefPtr def);
 void virDomainFSDefFree(virDomainFSDefPtr def);
 void virDomainActualNetDefFree(virDomainActualNetDefPtr def);

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index eb7ec769ca452f99df1c51a6e386b33356288a32..588b1c4adebd86acffc8ae57114c15fa57cef0d0 100644 (file)
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -249,6 +249,7 @@ virDomainDiskDefFree;
 virDomainDiskDefNew;
 virDomainDiskDefSourceParse;
 virDomainDiskDeviceTypeToString;
+virDomainDiskDiffersSourceOnly;
 virDomainDiskDiscardTypeToString;
 virDomainDiskErrorPolicyTypeFromString;
 virDomainDiskErrorPolicyTypeToString;

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index f352a88e45c24c2ad428807dda493e52aea352ce..9dbe6355b7ba10ca16a8f29f62c99b237e5da50c 100644 (file)
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -7920,6 +7920,9 @@ qemuDomainChangeDiskMediaLive(virConnectPtr conn,
             goto end;
         }
 
+        if (!virDomainDiskDiffersSourceOnly(disk, orig_disk))
+            goto end;
+
         /* Add the new disk src into shared disk hash table */
         if (qemuAddSharedDevice(driver, dev, vm->def->name) < 0)
             goto end;