CLOUDSTACK-9794: Unable to attach more than 14 devices to a VM

Updated hardcoded value with max data volumes limit from hypervisor capabilities.

Author: Suresh Kumar Anaparti

plugins/hypervisors/kvm/src/com/cloud/hypervisor/kvm/resource/LibvirtVMDef.java

@@ -584,18 +584,36 @@ public void defFileBasedDisk(String filePath, String diskLabel, DiskBus bus, Dis
 
         /* skip iso label */
         private String getDevLabel(int devId, DiskBus bus) {
+            if (devId < 0) {
+                return "";
+            }
+
             if (devId == 2) {
                 devId++;
             }
 
-            char suffix = (char)('a' + devId);
             if (bus == DiskBus.SCSI) {
-                return "sd" + suffix;
+                return "sd" + getDevLabelSuffix(devId);
             } else if (bus == DiskBus.VIRTIO) {
-                return "vd" + suffix;
+                return "vd" + getDevLabelSuffix(devId);
+            }
+            return "hd" + getDevLabelSuffix(devId);
+        }
+
+        private String getDevLabelSuffix(int deviceIndex) {
+            if (deviceIndex < 0) {
+                return "";
             }
-            return "hd" + suffix;
 
+            int base = 'z' - 'a' + 1;
+            String labelSuffix = "";
+            do {
+                char suffix = (char)('a' + (deviceIndex % base));
+                labelSuffix = suffix + labelSuffix;
+                deviceIndex = (deviceIndex / base) - 1;
+            } while (deviceIndex >= 0);
+
+            return labelSuffix;
         }
 
         public void defFileBasedDisk(String filePath, int devId, DiskBus bus, DiskFmtType diskFmtType) {
@@ -716,11 +734,6 @@ public DiskFmtType getDiskFormatType() {
             return _diskFmtType;
         }
 
-        public int getDiskSeq() {
-            char suffix = _diskLabel.charAt(_diskLabel.length() - 1);
-            return suffix - 'a';
-        }
-
         public void setBytesReadRate(Long bytesReadRate) {
             _bytesReadRate = bytesReadRate;
         }

server/src/com/cloud/storage/VolumeApiServiceImpl.java

@@ -1433,9 +1433,9 @@ public Volume attachVolumeToVM(Long vmId, Long volumeId, Long deviceId) {
         // that supported by hypervisor
         if (deviceId == null || deviceId.longValue() != 0) {
             List<VolumeVO> existingDataVolumes = _volsDao.findByInstanceAndType(vmId, Volume.Type.DATADISK);
-            int maxDataVolumesSupported = getMaxDataVolumesSupported(vm);
-            if (existingDataVolumes.size() >= maxDataVolumesSupported) {
-                throw new InvalidParameterValueException("The specified VM already has the maximum number of data disks (" + maxDataVolumesSupported + "). Please specify another VM.");
+            int maxAttachableDataVolumesSupported = getMaxDataVolumesSupported(vm) - 2; //IDs: 0 (ROOT) and 3 (CD-ROM) are reserved
+            if (existingDataVolumes.size() >= maxAttachableDataVolumesSupported) {
+                throw new InvalidParameterValueException("The specified VM already has the maximum number of data disks (" + maxAttachableDataVolumesSupported + ") attached. Please specify another VM.");
             }
         }
 
@@ -2527,7 +2527,7 @@ private VolumeVO sendAttachVolumeCommand(UserVmVO vm, VolumeVO volumeToAttach, L
 
             DataTO volTO = volFactory.getVolume(volumeToAttach.getId()).getTO();
 
-            deviceId = getDeviceId(vm.getId(), deviceId);
+            deviceId = getDeviceId(vm, deviceId);
 
             DiskTO disk = storageMgr.getDiskWithThrottling(volTO, volumeToAttach.getVolumeType(), deviceId, volumeToAttach.getPath(),
                     vm.getServiceOfferingId(), volumeToAttach.getDiskOfferingId());
@@ -2585,7 +2585,7 @@ private VolumeVO sendAttachVolumeCommand(UserVmVO vm, VolumeVO volumeToAttach, L
                     _volsDao.update(volumeToAttach.getId(), volumeToAttach);
                 }
             } else {
-                deviceId = getDeviceId(vm.getId(), deviceId);
+                deviceId = getDeviceId(vm, deviceId);
 
                 _volsDao.attachVolume(volumeToAttach.getId(), vm.getId(), deviceId);
             }
@@ -2623,7 +2623,7 @@ private int getMaxDataVolumesSupported(UserVmVO vm) {
             _hostDao.loadDetails(host);
             maxDataVolumesSupported = _hypervisorCapabilitiesDao.getMaxDataVolumesLimit(host.getHypervisorType(), host.getDetail("product_version"));
         }
-        if (maxDataVolumesSupported == null) {
+        if (maxDataVolumesSupported == null || maxDataVolumesSupported.intValue() <= 0) {
             maxDataVolumesSupported = 6; // 6 data disks by default if nothing
             // is specified in
             // 'hypervisor_capabilities' table
@@ -2632,28 +2632,32 @@ private int getMaxDataVolumesSupported(UserVmVO vm) {
         return maxDataVolumesSupported.intValue();
     }
 
-    private Long getDeviceId(long vmId, Long deviceId) {
+    private Long getDeviceId(UserVmVO vm, Long deviceId) {
         // allocate deviceId
-        List<VolumeVO> vols = _volsDao.findByInstance(vmId);
+        int maxDeviceId = getMaxDataVolumesSupported(vm) - 1;
+        List<VolumeVO> vols = _volsDao.findByInstance(vm.getId());
         if (deviceId != null) {
-            if (deviceId.longValue() > 15 || deviceId.longValue() == 3) {
-                throw new RuntimeException("deviceId should be 1,2,4-15");
+            if (deviceId.longValue() <= 0 || deviceId.longValue() > maxDeviceId || deviceId.longValue() == 3) {
+                throw new RuntimeException("deviceId should be 1,2,4-" + maxDeviceId);
             }
             for (VolumeVO vol : vols) {
                 if (vol.getDeviceId().equals(deviceId)) {
-                    throw new RuntimeException("deviceId " + deviceId + " is used by vm" + vmId);
+                    throw new RuntimeException("deviceId " + deviceId + " is used by vm " + vm.getId());
                 }
             }
         } else {
             // allocate deviceId here
             List<String> devIds = new ArrayList<String>();
-            for (int i = 1; i < 15; i++) {
+            for (int i = 1; i <= maxDeviceId; i++) {
                 devIds.add(String.valueOf(i));
             }
             devIds.remove("3");
             for (VolumeVO vol : vols) {
                 devIds.remove(vol.getDeviceId().toString().trim());
             }
+            if (devIds.isEmpty()) {
+                throw new RuntimeException("All device Ids are used by vm " + vm.getId());
+            }
             deviceId = Long.parseLong(devIds.iterator().next());
         }