From c00b2f0dd120c81c3bc87f1def154b6f60fc9a8c Mon Sep 17 00:00:00 2001
From: John Ferlan <jferlan@redhat.com>
Date: Thu, 18 Jul 2013 13:18:03 -0400
Subject: [PATCH] conf: Introduce new XML tag "mode" for disk source

There are two ways to use a iSCSI LUN as disk source for qemu.

 * The LUN's path as it shows up on host, e.g.
   /dev/disk/by-path/ip-$ip:3260-iscsi-$iqn-fc18:iscsi.iscsi0-lun-1

 * The libiscsi URI from the storage pool source element host attribute, e.g.
   iscsi://demo.org:6000/iqn.1992-01.com.example/1

For a "volume" type disk, if the specified "pool" is of iscsi
type, we should support to use the LUN in either of above 2 ways.
That's why to introduce a new XML tag "mode" for the disk source
(libvirt should support iscsi pool with libiscsi, but it's another
new feature, which should be done later).

The "mode" can be either of "host" or "direct". Use "host" to indicate
use of the LUN with the path as it shows up on host. Use "direct" to
indicate to use it with the source pool host URI (future patches may support
to use network type libvirt storage too, e.g. Ceph)
---
 docs/formatdomain.html.in                     | 11 ++++-
 docs/schemas/domaincommon.rng                 |  8 ++++
 src/conf/domain_conf.c                        | 22 ++++++++-
 src/conf/domain_conf.h                        | 22 +++++++++
 .../qemuxml2argv-disk-source-pool-mode.xml    | 48 +++++++++++++++++++
 tests/qemuxml2xmltest.c                       |  1 +
 6 files changed, 110 insertions(+), 2 deletions(-)
 create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-source-pool-mode.xml

diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index b1c3bfca3e..7601aaaf54 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -1601,7 +1601,16 @@
         <code>pool</code> and <code>volume</code>. Attribute <code>pool</code>
         specifies the name of storage pool (managed by libvirt) where the disk
         source resides, and attribute <code>volume</code> specifies the name of
-        storage volume (managed by libvirt) used as the disk source.
+        storage volume (managed by libvirt) used as the disk source. For a
+        "volume" type disk, if the underlying storage pool is "iscsi", attribute
+        <code>mode</code> (<span class="since">since 1.1.1</span>) can be used
+        to indicate how to represent the LUN as the disk source. The value
+        "host" indicates to use the LUN's path as it shows up on host, e.g.
+        /dev/disk/by-path/ip-10.11.12.9:3260-iscsi-iqn.2013-06.fc:iscsi.iscsi0-lun-1).
+        The value "direct" indicates to use the storage pool's
+        <code>source</code> element <code>host</code> attribute as the
+        disk source for the libiscsi URI, e.g.
+        file=iscsi://demo.org:6000/iqn.1992-01.com.example/1.
         <span class="since">Since 0.0.3; <code>type='dir'</code> since
         0.7.5; <code>type='network'</code> since
         0.8.7; <code>protocol='iscsi'</code> since 1.0.4;
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 7a6852b377..745b959a8f 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -1173,6 +1173,14 @@
                 <attribute name="volume">
                   <ref name="volName"/>
                 </attribute>
+                <optional>
+                  <attribute name="mode">
+                    <choice>
+                      <value>host</value>
+                      <value>direct</value>
+                    </choice>
+                  </attribute>
+                </optional>
                 <optional>
                   <ref name="startupPolicy"/>
                 </optional>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 308a96beef..297553c23a 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -761,6 +761,11 @@ VIR_ENUM_IMPL(virDomainDiskDiscard, VIR_DOMAIN_DISK_DISCARD_LAST,
               "default",
               "unmap",
               "ignore")
+VIR_ENUM_IMPL(virDomainDiskSourcePoolMode,
+              VIR_DOMAIN_DISK_SOURCE_POOL_MODE_LAST,
+              "default",
+              "host",
+              "direct")
 
 #define VIR_DOMAIN_XML_WRITE_FLAGS  VIR_DOMAIN_XML_SECURE
 #define VIR_DOMAIN_XML_READ_FLAGS   VIR_DOMAIN_XML_INACTIVE
@@ -4645,10 +4650,12 @@ virDomainDiskSourcePoolDefParse(xmlNodePtr node,
 {
     char *pool = NULL;
     char *volume = NULL;
+    char *mode = NULL;
     int ret = -1;
 
     pool = virXMLPropString(node, "pool");
     volume = virXMLPropString(node, "volume");
+    mode = virXMLPropString(node, "mode");
 
     /* CD-ROM and Floppy allows no source */
     if (!pool && !volume)
@@ -4664,6 +4671,14 @@ virDomainDiskSourcePoolDefParse(xmlNodePtr node,
     if (VIR_ALLOC(def->srcpool) < 0)
         goto cleanup;
 
+    if (mode && (def->srcpool->mode =
+                 virDomainDiskSourcePoolModeTypeFromString(mode)) <= 0) {
+        virReportError(VIR_ERR_XML_ERROR,
+                       _("unknown source mode '%s' for volume type disk"),
+                       mode);
+        goto cleanup;
+    }
+
     def->srcpool->pool = pool;
     pool = NULL;
     def->srcpool->volume = volume;
@@ -4674,6 +4689,7 @@ virDomainDiskSourcePoolDefParse(xmlNodePtr node,
 cleanup:
     VIR_FREE(pool);
     VIR_FREE(volume);
+    VIR_FREE(mode);
     return ret;
 }
 
@@ -14157,9 +14173,13 @@ virDomainDiskSourceDefFormat(virBufferPtr buf,
         case VIR_DOMAIN_DISK_TYPE_VOLUME:
             virBufferAddLit(buf, "      <source");
 
-            if (def->srcpool)
+            if (def->srcpool) {
                 virBufferAsprintf(buf, " pool='%s' volume='%s'",
                                   def->srcpool->pool, def->srcpool->volume);
+                if (def->srcpool->mode)
+                    virBufferAsprintf(buf, " mode='%s'",
+                                      virDomainDiskSourcePoolModeTypeToString(def->srcpool->mode));
+            }
             if (def->startupPolicy)
                 virBufferEscapeString(buf, " startupPolicy='%s'", startupPolicy);
 
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 00d3c3a4ab..900fb01f05 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -652,11 +652,32 @@ struct _virDomainBlockIoTuneInfo {
 };
 typedef virDomainBlockIoTuneInfo *virDomainBlockIoTuneInfoPtr;
 
+/*
+ * Used for volume "type" disk to indicate how to represent
+ * the disk source if the specified "pool" is of iscsi type.
+ */
+enum virDomainDiskSourcePoolMode {
+    VIR_DOMAIN_DISK_SOURCE_POOL_MODE_DEFAULT = 0,
+
+    /* Use the path as it shows up on host, e.g.
+     * /dev/disk/by-path/ip-$ip-iscsi-$iqn:iscsi.iscsi-pool0-lun-1
+     */
+    VIR_DOMAIN_DISK_SOURCE_POOL_MODE_HOST,
+
+    /* Use the URI from the storage pool source element host attribute. E.g.
+     * file=iscsi://demo.org:6000/iqn.1992-01.com.example/1.
+     */
+    VIR_DOMAIN_DISK_SOURCE_POOL_MODE_DIRECT,
+
+    VIR_DOMAIN_DISK_SOURCE_POOL_MODE_LAST
+};
+
 typedef struct _virDomainDiskSourcePoolDef virDomainDiskSourcePoolDef;
 struct _virDomainDiskSourcePoolDef {
     char *pool; /* pool name */
     char *volume; /* volume name */
     int voltype; /* enum virStorageVolType, internal only */
+    int mode; /* enum virDomainDiskSourcePoolMode */
 };
 typedef virDomainDiskSourcePoolDef *virDomainDiskSourcePoolDefPtr;
 
@@ -2554,6 +2575,7 @@ VIR_ENUM_DECL(virDomainDiskSecretType)
 VIR_ENUM_DECL(virDomainDeviceSGIO)
 VIR_ENUM_DECL(virDomainDiskTray)
 VIR_ENUM_DECL(virDomainDiskDiscard)
+VIR_ENUM_DECL(virDomainDiskSourcePoolMode)
 VIR_ENUM_DECL(virDomainIoEventFd)
 VIR_ENUM_DECL(virDomainVirtioEventIdx)
 VIR_ENUM_DECL(virDomainDiskCopyOnRead)
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-source-pool-mode.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-source-pool-mode.xml
new file mode 100644
index 0000000000..b907633b96
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-source-pool-mode.xml
@@ -0,0 +1,48 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <disk type='volume' device='cdrom'>
+      <source pool='blk-pool0' volume='blk-pool0-vol0' mode='host' startupPolicy='optional'>
+        <seclabel model='selinux' relabel='yes'>
+          <label>system_u:system_r:public_content_t:s0</label>
+        </seclabel>
+      </source>
+      <target dev='hda' bus='ide'/>
+      <readonly/>
+      <address type='drive' controller='0' bus='0' target='0' unit='1'/>
+    </disk>
+    <disk type='volume' device='cdrom'>
+      <source pool='blk-pool0' volume='blk-pool0-vol1' mode='direct' startupPolicy='optional'>
+        <seclabel model='selinux' relabel='yes'>
+          <label>system_u:system_r:public_content_t:s0</label>
+        </seclabel>
+      </source>
+      <target dev='hda' bus='ide'/>
+      <readonly/>
+      <address type='drive' controller='0' bus='0' target='0' unit='2'/>
+    </disk>
+    <disk type='file' device='disk'>
+      <source file='/tmp/idedisk.img'/>
+      <target dev='hdc' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='3'/>
+    </disk>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <controller type='ide' index='1'/>
+    <controller type='pci' index='0' model='pci-root'/>
+    <memballoon model='virtio'/>
+  </devices>
+</domain>
diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c
index 76570c5c95..77cac3f687 100644
--- a/tests/qemuxml2xmltest.c
+++ b/tests/qemuxml2xmltest.c
@@ -264,6 +264,7 @@ mymain(void)
 
     DO_TEST("disk-scsi-disk-vpd");
     DO_TEST("disk-source-pool");
+    DO_TEST("disk-source-pool-mode");
 
     DO_TEST("disk-drive-discard");
 
-- 
2.47.2