qemuDomainPrepareHostdev: Don't base backend nodename on device alias

QEMU's blockdev nodenames which are used to back SCSI/iSCSI hostdevs are
limited to 32 characters. If a user passes a very long user alias as
name of the host device it's easy to end up with a too-long nodename.

To prevent this from happening don't base the nodename on the possibly
user-specified alias but on the normal sequential node name generator.

We then store the name in the status XML for further use.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/qemu/qemu_domain.c

@@ -10429,7 +10429,8 @@ qemuDomainPrepareHostdev(virDomainHostdevDefPtr hostdev,
             const char *backendalias = hostdev->info->alias;
 
             if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV_HOSTDEV_SCSI)) {
-                src->nodestorage = g_strdup_printf("libvirt-%s-backend", hostdev->info->alias);
+                src->id = qemuDomainStorageIdNew(priv);
+                src->nodestorage = g_strdup_printf("libvirt-%d-backend", src->id);
                 backendalias = src->nodestorage;
             }
 

tests/qemuxml2argvdata/hostdev-scsi-lsi.x86_64-latest.args

@@ -35,41 +35,35 @@ file=/tmp/lib/domain--1-QEMUGuest2/master-key.aes \
 "file":"libvirt-1-storage"}' \
 -device ide-hd,bus=ide.0,unit=0,drive=libvirt-1-format,id=ide0-0-0,bootindex=1 \
 -blockdev '{"driver":"host_device","filename":"/dev/sg0",\
-"node-name":"libvirt-hostdev0-backend","read-only":false}' \
--device scsi-generic,bus=scsi0.0,scsi-id=7,drive=libvirt-hostdev0-backend,\
-id=hostdev0 \
+"node-name":"libvirt-2-backend","read-only":false}' \
+-device scsi-generic,bus=scsi0.0,scsi-id=7,drive=libvirt-2-backend,id=hostdev0 \
 -blockdev '{"driver":"host_device","filename":"/dev/sg0",\
-"node-name":"libvirt-hostdev1-backend","read-only":true}' \
--device scsi-generic,bus=scsi0.0,scsi-id=6,drive=libvirt-hostdev1-backend,\
-id=hostdev1 \
+"node-name":"libvirt-3-backend","read-only":true}' \
+-device scsi-generic,bus=scsi0.0,scsi-id=6,drive=libvirt-3-backend,id=hostdev1 \
 -blockdev '{"driver":"iscsi","portal":"example.org:3260",\
 "target":"iqn.1992-01.com.example","lun":0,"transport":"tcp",\
-"node-name":"libvirt-hostdev2-backend","read-only":false}' \
--device scsi-generic,bus=scsi0.0,scsi-id=4,drive=libvirt-hostdev2-backend,\
-id=hostdev2 \
+"node-name":"libvirt-4-backend","read-only":false}' \
+-device scsi-generic,bus=scsi0.0,scsi-id=4,drive=libvirt-4-backend,id=hostdev2 \
 -blockdev '{"driver":"iscsi","portal":"example.org:3260",\
 "target":"iqn.1992-01.com.example","lun":1,"transport":"tcp",\
-"node-name":"libvirt-hostdev3-backend","read-only":false}' \
--device scsi-generic,bus=scsi0.0,scsi-id=5,drive=libvirt-hostdev3-backend,\
-id=hostdev3 \
--object secret,id=libvirt-hostdev4-backend-secret0,\
+"node-name":"libvirt-5-backend","read-only":false}' \
+-device scsi-generic,bus=scsi0.0,scsi-id=5,drive=libvirt-5-backend,id=hostdev3 \
+-object secret,id=libvirt-6-backend-secret0,\
 data=9eao5F8qtkGt+seB1HYivWIxbtwUu6MQtg1zpj/oDtUsPr1q8wBYM91uEHCn6j/1,\
 keyid=masterKey0,iv=AAECAwQFBgcICQoLDA0ODw==,format=base64 \
 -blockdev '{"driver":"iscsi","portal":"example.org:3260",\
 "target":"iqn.1992-01.com.example:storage","lun":1,"transport":"tcp",\
-"user":"myname","password-secret":"libvirt-hostdev4-backend-secret0",\
-"node-name":"libvirt-hostdev4-backend","read-only":false}' \
--device scsi-generic,bus=scsi0.0,scsi-id=3,drive=libvirt-hostdev4-backend,\
-id=hostdev4 \
--object secret,id=libvirt-hostdev5-backend-secret0,\
+"user":"myname","password-secret":"libvirt-6-backend-secret0",\
+"node-name":"libvirt-6-backend","read-only":false}' \
+-device scsi-generic,bus=scsi0.0,scsi-id=3,drive=libvirt-6-backend,id=hostdev4 \
+-object secret,id=libvirt-7-backend-secret0,\
 data=9eao5F8qtkGt+seB1HYivWIxbtwUu6MQtg1zpj/oDtUsPr1q8wBYM91uEHCn6j/1,\
 keyid=masterKey0,iv=AAECAwQFBgcICQoLDA0ODw==,format=base64 \
 -blockdev '{"driver":"iscsi","portal":"example.org:3260",\
 "target":"iqn.1992-01.com.example:storage","lun":2,"transport":"tcp",\
-"user":"myname","password-secret":"libvirt-hostdev5-backend-secret0",\
-"node-name":"libvirt-hostdev5-backend","read-only":false}' \
--device scsi-generic,bus=scsi0.0,scsi-id=2,drive=libvirt-hostdev5-backend,\
-id=hostdev5 \
+"user":"myname","password-secret":"libvirt-7-backend-secret0",\
+"node-name":"libvirt-7-backend","read-only":false}' \
+-device scsi-generic,bus=scsi0.0,scsi-id=2,drive=libvirt-7-backend,id=hostdev5 \
 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3 \
 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,\
 resourcecontrol=deny \

tests/qemuxml2argvdata/hostdev-scsi-virtio-scsi.x86_64-latest.args

@@ -35,46 +35,46 @@ file=/tmp/lib/domain--1-QEMUGuest2/master-key.aes \
 "file":"libvirt-1-storage"}' \
 -device ide-hd,bus=ide.0,unit=0,drive=libvirt-1-format,id=ide0-0-0,bootindex=1 \
 -blockdev '{"driver":"host_device","filename":"/dev/sg0",\
-"node-name":"libvirt-hostdev0-backend","read-only":false}' \
+"node-name":"libvirt-2-backend","read-only":false}' \
 -device scsi-generic,bus=scsi0.0,channel=0,scsi-id=4,lun=8,\
-drive=libvirt-hostdev0-backend,id=hostdev0 \
+drive=libvirt-2-backend,id=hostdev0 \
 -blockdev '{"driver":"host_device","filename":"/dev/sg0",\
-"node-name":"libvirt-hostdev1-backend","read-only":true}' \
+"node-name":"libvirt-3-backend","read-only":true}' \
 -device scsi-generic,bus=scsi0.0,channel=0,scsi-id=4,lun=7,\
-drive=libvirt-hostdev1-backend,id=hostdev1 \
+drive=libvirt-3-backend,id=hostdev1 \
 -blockdev '{"driver":"host_device","filename":"/dev/sg0",\
-"node-name":"libvirt-ua-test-backend","read-only":false}' \
+"node-name":"libvirt-4-backend","read-only":false}' \
 -device scsi-generic,bus=scsi0.0,channel=0,scsi-id=4,lun=6,\
-drive=libvirt-ua-test-backend,id=ua-test \
+drive=libvirt-4-backend,id=ua-test \
 -blockdev '{"driver":"iscsi","portal":"example.org:3260",\
 "target":"iqn.1992-01.com.example","lun":0,"transport":"tcp",\
-"node-name":"libvirt-hostdev2-backend","read-only":false}' \
+"node-name":"libvirt-5-backend","read-only":false}' \
 -device scsi-generic,bus=scsi0.0,channel=0,scsi-id=2,lun=4,\
-drive=libvirt-hostdev2-backend,id=hostdev2 \
+drive=libvirt-5-backend,id=hostdev2 \
 -blockdev '{"driver":"iscsi","portal":"example.org:3260",\
 "target":"iqn.1992-01.com.example","lun":1,"transport":"tcp",\
-"node-name":"libvirt-hostdev3-backend","read-only":false}' \
+"node-name":"libvirt-6-backend","read-only":false}' \
 -device scsi-generic,bus=scsi0.0,channel=0,scsi-id=2,lun=5,\
-drive=libvirt-hostdev3-backend,id=hostdev3 \
--object secret,id=libvirt-hostdev4-backend-secret0,\
+drive=libvirt-6-backend,id=hostdev3 \
+-object secret,id=libvirt-7-backend-secret0,\
 data=9eao5F8qtkGt+seB1HYivWIxbtwUu6MQtg1zpj/oDtUsPr1q8wBYM91uEHCn6j/1,\
 keyid=masterKey0,iv=AAECAwQFBgcICQoLDA0ODw==,format=base64 \
 -blockdev '{"driver":"iscsi","portal":"example.org:3260",\
 "target":"iqn.1992-01.com.example:storage","lun":1,"transport":"tcp",\
-"user":"myname","password-secret":"libvirt-hostdev4-backend-secret0",\
-"node-name":"libvirt-hostdev4-backend","read-only":false}' \
+"user":"myname","password-secret":"libvirt-7-backend-secret0",\
+"node-name":"libvirt-7-backend","read-only":false}' \
 -device scsi-generic,bus=scsi0.0,channel=0,scsi-id=3,lun=4,\
-drive=libvirt-hostdev4-backend,id=hostdev4 \
--object secret,id=libvirt-hostdev5-backend-secret0,\
+drive=libvirt-7-backend,id=hostdev4 \
+-object secret,id=libvirt-8-backend-secret0,\
 data=9eao5F8qtkGt+seB1HYivWIxbtwUu6MQtg1zpj/oDtUsPr1q8wBYM91uEHCn6j/1,\
 keyid=masterKey0,iv=AAECAwQFBgcICQoLDA0ODw==,format=base64 \
 -blockdev '{"driver":"iscsi","portal":"example.org:3260",\
 "target":"iqn.1992-01.com.example:storage","lun":2,"transport":"tcp",\
-"user":"myname","password-secret":"libvirt-hostdev5-backend-secret0",\
+"user":"myname","password-secret":"libvirt-8-backend-secret0",\
 "initiator-name":"iqn.2020-07.com.example:test",\
-"node-name":"libvirt-hostdev5-backend","read-only":false}' \
+"node-name":"libvirt-8-backend","read-only":false}' \
 -device scsi-generic,bus=scsi0.0,channel=0,scsi-id=3,lun=5,\
-drive=libvirt-hostdev5-backend,id=hostdev5 \
+drive=libvirt-8-backend,id=hostdev5 \
 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3 \
 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,\
 resourcecontrol=deny \