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kvm: Do not set backing file format of DATADISK in vm start/migration #4800

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Merged
DaanHoogland merged 2 commits into from
Mar 24, 2021
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kvm: Do not set backing file format of DATADISK in vm start/migration #4800

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kvm: Do not rebase DATADISK in vm start/migration
ustcweizhou Mar 11, 2021
ef0321d
#4800: add comment and use isBlank
ustcweizhou Mar 12, 2021
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6 changes: 5 additions & 1 deletion ...rvisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/LibvirtComputingResource.java
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Original file line number Diff line number Diff line change
Expand Up @@ -4266,7 +4266,11 @@ public void setBackingFileFormat(String volPath) {
Map<String, String> info = qemu.info(file);
String backingFilePath = info.get(new String("backing_file"));

@rubieHess rubieHess Mar 21, 2021

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I detect that this code is problematic. According to the Performance (PERFORMANCE), Dm: Method invokes inefficient new String(String) constructor (DM_STRING_CTOR).
Using the java.lang.String(String) constructor wastes memory because the object so constructed will be functionally indistinguishable from the String passed as a parameter.  Just use the argument String directly.

@weizhouapache weizhouapache Mar 22, 2021

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@rubieHess good point. thanks ! I will create a pr for it.

@rubieHess rubieHess Mar 22, 2021

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Happy to help.

String backingFileFormat = info.get(new String("backing_file_format"));
if (org.apache.commons.lang.StringUtils.isEmpty(backingFileFormat)) {
if (org.apache.commons.lang.StringUtils.isNotBlank(backingFilePath)
&& org.apache.commons.lang.StringUtils.isBlank(backingFileFormat)) {
// VMs which are created in CloudStack 4.14 and before cannot be started or migrated
// in latest Linux distributions due to missing backing file format
// Please refer to https://libvirt.org/kbase/backing_chains.html#vm-refuses-to-start-due-to-misconfigured-backing-store-format
s_logger.info("Setting backing file format of " + volPath);
QemuImgFile backingFile = new QemuImgFile(backingFilePath);
Map<String, String> backingFileinfo = qemu.info(backingFile);
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