On 10.07.2015 08:20, Martin Kletzander wrote:

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 Signed-off-by: Martin Kletzander <mkletzan@redhat.com> ---

Notes: v2: - Don't say 'NULL' when it should be 'unspecified' - Don't blindly copy field name into the error message, but use space instead of dot. That way it looks the same as in the XML provided. - Check strings properly instead of addresses

src/conf/domain_conf.c | 133 +++++++++++++++++++++++++++++++++++++++++++++++ src/conf/domain_conf.h | 2 + src/libvirt_private.syms | 1 + src/qemu/qemu_driver.c | 3 ++ 4 files changed, 139 insertions(+)

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 1f7862b00463..69e5df27c270 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -5690,6 +5690,139 @@ 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) +{

Nice work, but I think this should go somewhere into src/qemu/. I mean, some o these fields are not changeable as a domain is running. But some might be depending on the underlying hypervisor. For instance, xen might be able to change serial number of a HDD. On the other hand, that might be just a few corner cases I'm talking about, so it's up to you what you prefer more.

+#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); + + if (disk->transient && STRNEQ(disk->transient, orig_disk->transient)) { + virReportError(VIR_ERR_OPERATION_UNSUPPORTED, + _("cannot modify field '%s' of the disk"), + "transient"); + return false; + } + + 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 50750c1dfa14..0fe6b1a47c8f 100644 --- 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 720afdf4dd11..1c7c492951ba 100644 --- 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 c4b3979f89ef..62bba2ea4054 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -7916,6 +7916,9 @@ 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;

ACK Michal