From b7945d7e44a533d7a9cc26d493f7abb9ebccaae4 Mon Sep 17 00:00:00 2001

Message-Id: <b7945d7e44a533d7a9cc26d493f7abb9ebccaae4@dist-git>

From: Peter Krempa <pkrempa@redhat.com>

Date: Fri, 21 Nov 2014 15:04:11 +0100

Subject: [PATCH] storage: rbd: qemu: Add support for specifying internal RBD

 snapshots

https://bugzilla.redhat.com/show_bug.cgi?id=1164528

Some storage systems have internal support for snapshots. Libvirt should

be able to select a correct snapshot when starting a VM.

This patch adds a XML element to select a storage source snapshot for

the RBD protocol which supports this feature.

(cherry picked from commit 02556606584ef6c065eae6e36c311250fa7a24f4)

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

---

 docs/formatdomain.html.in                          | 16 +++++++--

 docs/schemas/domaincommon.rng                      |  8 +++++

 src/conf/domain_conf.c                             | 38 +++++++++++++++++++---

 src/conf/domain_conf.h                             |  1 +

 src/conf/snapshot_conf.c                           |  6 ++--

 src/qemu/qemu_command.c                            |  3 ++

 src/util/virstoragefile.c                          |  8 +++++

 src/util/virstoragefile.h                          |  1 +

 .../qemuxml2argv-disk-drive-network-rbd.args       |  4 +++

 .../qemuxml2argv-disk-drive-network-rbd.xml        | 17 ++++++++++

 10 files changed, 93 insertions(+), 9 deletions(-)

diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in

index a458067..789f6ee 100644

--- a/docs/formatdomain.html.in

+++ b/docs/formatdomain.html.in

@@ -1661,6 +1661,7 @@

       <driver name="qemu" type="raw"/>

       <source protocol="rbd" name="image_name2">

         <host name="hostname" port="7000"/>

+        <snapshot name="snapname"/>

       </source>

       <target dev="hdc" bus="ide"/>

       <auth username='myuser'>

@@ -1934,15 +1935,17 @@

         is only valid when the specified storage volume is of 'file' or

         'block' type).

-        When the disk type is "network", the source

-        may have zero or more host sub-elements used to

-        specify the hosts to connect.

+        The source element may contain the following sub elements:

           
host

+            When the disk type is "network", the source

+            may have zero or more host sub-elements used to

+            specify the hosts to connect.

+

             The host element supports 4 attributes, viz.  "name",

             "port", "transport" and "socket", which specify the hostname,

             the port number, transport type and path to socket, respectively.

@@ -1995,6 +1998,13 @@

             AF_UNIX socket.

+          
snapshot

+          

+            The name attribute of snapshot element can

+            optionally specify an internal snapshot name to be used as the

+            source for storage protocols.

+            Supported for 'rbd' since 1.2.11 (QEMU only).

+          

diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng

index c010c45..fa17494 100644

--- a/docs/schemas/domaincommon.rng

+++ b/docs/schemas/domaincommon.rng

@@ -1447,6 +1447,14 @@

             </choice>

           </element>

         </zeroOrMore>

+        <optional>

+          <element name="snapshot">

+            <attribute name="name">

+              <ref name="genericName"/>

+            </attribute>

+            <empty/>

+          </element>

+        </optional>

         <empty/>

       </element>

     </interleave>

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c

index 0e977fc..82d321a 100644

--- a/src/conf/domain_conf.c

+++ b/src/conf/domain_conf.c

@@ -3157,6 +3157,22 @@ virDomainDeviceDefPostParseInternal(virDomainDeviceDefPtr dev,

             return -1;

     }

+    /* verify disk source */

+    if (dev->type == VIR_DOMAIN_DEVICE_DISK) {

+        virDomainDiskDefPtr disk = dev->data.disk;

+

+        /* internal snapshots are currently supported only with rbd: */

+        if (virStorageSourceGetActualType(disk->src) != VIR_STORAGE_TYPE_NETWORK &&

+            disk->src->protocol != VIR_STORAGE_NET_PROTOCOL_RBD) {

+            if (disk->src->snapshot) {

+                virReportError(VIR_ERR_XML_ERROR, "%s",

+                               _("<snapshot> element is currently supported "

+                                 "only with 'rbd' disks"));

+                return -1;

+            }

+        }

+    }

+

     return 0;

 }

@@ -5301,10 +5317,14 @@ virDomainDiskSourcePoolDefParse(xmlNodePtr node,

 int

 virDomainDiskSourceParse(xmlNodePtr node,

+                         xmlXPathContextPtr ctxt,

                          virStorageSourcePtr src)

 {

     int ret = -1;

     char *protocol = NULL;

+    xmlNodePtr saveNode = ctxt->node;

+

+    ctxt->node = node;

     switch ((virStorageType)src->type) {

     case VIR_STORAGE_TYPE_FILE:

@@ -5357,6 +5377,9 @@ virDomainDiskSourceParse(xmlNodePtr node,

             tmp[0] = '\0';

         }

+        /* snapshot currently works only for remote disks */

+        src->snapshot = virXPathString("string(./snapshot/@name)", ctxt);

+

         if (virDomainStorageHostParse(node, &src->hosts, &src->nhosts) < 0)

             goto cleanup;

         break;

@@ -5382,6 +5405,7 @@ virDomainDiskSourceParse(xmlNodePtr node,

  cleanup:

     VIR_FREE(protocol);

+    ctxt->node = saveNode;

     return ret;

 }

@@ -5437,7 +5461,7 @@ virDomainDiskBackingStoreParse(xmlXPathContextPtr ctxt,

         goto cleanup;

     }

-    if (virDomainDiskSourceParse(source, backingStore) < 0 ||

+    if (virDomainDiskSourceParse(source, ctxt, backingStore) < 0 ||

         virDomainDiskBackingStoreParse(ctxt, backingStore) < 0)

         goto cleanup;

@@ -5547,7 +5571,7 @@ virDomainDiskDefParseXML(virDomainXMLOptionPtr xmlopt,

                 xmlStrEqual(cur->name, BAD_CAST "source")) {

                 sourceNode = cur;

-                if (virDomainDiskSourceParse(cur, def->src) < 0)

+                if (virDomainDiskSourceParse(cur, ctxt, def->src) < 0)

                     goto error;

                 source = def->src->path;

@@ -5713,7 +5737,8 @@ virDomainDiskDefParseXML(virDomainXMLOptionPtr xmlopt,

                                        _("mirror requires source element"));

                         goto error;

                     }

-                    if (virDomainDiskSourceParse(mirrorNode, def->mirror) < 0)

+                    if (virDomainDiskSourceParse(mirrorNode, ctxt,

+                                                 def->mirror) < 0)

                         goto error;

                 }

                 ready = virXMLPropString(cur, "ready");

@@ -15898,11 +15923,12 @@ virDomainDiskSourceFormatInternal(virBufferPtr buf,

             VIR_FREE(path);

-            if (src->nhosts == 0) {

+            if (src->nhosts == 0 && !src->snapshot) {

                 virBufferAddLit(buf, "/>\n");

             } else {

                 virBufferAddLit(buf, ">\n");

                 virBufferAdjustIndent(buf, 2);

+

                 for (n = 0; n < src->nhosts; n++) {

                     virBufferAddLit(buf, "

                     virBufferEscapeString(buf, " name='%s'",

@@ -15919,6 +15945,10 @@ virDomainDiskSourceFormatInternal(virBufferPtr buf,

                     virBufferAddLit(buf, "/>\n");

                 }

+

+                virBufferEscapeString(buf, "<snapshot name='%s'/>\n",

+                                      src->snapshot);

+

                 virBufferAdjustIndent(buf, -2);

                 virBufferAddLit(buf, "</source>\n");

             }

diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h

index 21d19cf..6768089 100644

--- a/src/conf/domain_conf.h

+++ b/src/conf/domain_conf.h

@@ -2445,6 +2445,7 @@ virDomainDiskRemove(virDomainDefPtr def, size_t i);

 virDomainDiskDefPtr

 virDomainDiskRemoveByName(virDomainDefPtr def, const char *name);

 int virDomainDiskSourceParse(xmlNodePtr node,

+                             xmlXPathContextPtr ctxt,

                              virStorageSourcePtr src);

 bool virDomainHasDiskMirror(virDomainObjPtr vm);

diff --git a/src/conf/snapshot_conf.c b/src/conf/snapshot_conf.c

index c53a66b..27882b8 100644

--- a/src/conf/snapshot_conf.c

+++ b/src/conf/snapshot_conf.c

@@ -107,6 +107,7 @@ void virDomainSnapshotDefFree(virDomainSnapshotDefPtr def)

 static int

 virDomainSnapshotDiskDefParseXML(xmlNodePtr node,

+                                 xmlXPathContextPtr ctxt,

                                  virDomainSnapshotDiskDefPtr def)

 {

     int ret = -1;

@@ -154,7 +155,7 @@ virDomainSnapshotDiskDefParseXML(xmlNodePtr node,

         if (!def->src->path &&

             xmlStrEqual(cur->name, BAD_CAST "source")) {

-            if (virDomainDiskSourceParse(cur, def->src) < 0)

+            if (virDomainDiskSourceParse(cur, ctxt, def->src) < 0)

                 goto cleanup;

         } else if (!def->src->format &&

@@ -352,7 +353,8 @@ virDomainSnapshotDefParse(xmlXPathContextPtr ctxt,

             goto cleanup;

         def->ndisks = n;

         for (i = 0; i < def->ndisks; i++) {

-            if (virDomainSnapshotDiskDefParseXML(nodes[i], &def->disks[i]) < 0)

+            if (virDomainSnapshotDiskDefParseXML(nodes[i], ctxt,

+                                                 &def->disks[i]) < 0)

                 goto cleanup;

         }

         VIR_FREE(nodes);

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c

index 93f02a9..5d34ba3 100644

--- a/src/qemu/qemu_command.c

+++ b/src/qemu/qemu_command.c

@@ -2986,6 +2986,9 @@ qemuBuildNetworkDriveURI(virStorageSourcePtr src,

             virBufferStrcat(&buf, "rbd:", src->path, NULL);

+            if (src->snapshot)

+                virBufferEscape(&buf, '\\', ":", "@%s", src->snapshot);

+

             if (username) {

                 virBufferEscape(&buf, '\\', ":", ":id=%s", username);

                 virBufferEscape(&buf, '\\', ":",

diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c

index ba4d830..6cdc5be 100644

--- a/src/util/virstoragefile.c

+++ b/src/util/virstoragefile.c

@@ -1842,6 +1842,7 @@ virStorageSourceCopy(const virStorageSource *src,

         VIR_STRDUP(ret->driverName, src->driverName) < 0 ||

         VIR_STRDUP(ret->relPath, src->relPath) < 0 ||

         VIR_STRDUP(ret->backingStoreRaw, src->backingStoreRaw) < 0 ||

+        VIR_STRDUP(ret->snapshot, src->snapshot) < 0 ||

         VIR_STRDUP(ret->compat, src->compat) < 0)

         goto error;

@@ -2259,6 +2260,13 @@ virStorageSourceParseRBDColonString(const char *rbdstr,

         *p = '\0';

     }

+    /* snapshot name */

+    if ((p = strchr(src->path, '@'))) {

+        if (VIR_STRDUP(src->snapshot, p + 1) < 0)

+            goto error;

+        *p = '\0';

+    }

+

     /* options */

     if (!options)

         return 0; /* all done */

diff --git a/src/util/virstoragefile.h b/src/util/virstoragefile.h

index 3573ccd..74aa1a3 100644

--- a/src/util/virstoragefile.h

+++ b/src/util/virstoragefile.h

@@ -236,6 +236,7 @@ struct _virStorageSource {

     char *path;

     int protocol; /* virStorageNetProtocol */

     char *volume; /* volume name for remote storage */

+    char *snapshot; /* for storage systems supporting internal snapshots */

     size_t nhosts;

     virStorageNetHostDefPtr hosts;

     virStorageSourcePoolDefPtr srcpool;

diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-network-rbd.args b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-network-rbd.args

index 21d7b64..e4f1389 100644

--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-network-rbd.args

+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-network-rbd.args

@@ -5,4 +5,8 @@ unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -usb \

 -drive 'file=rbd:pool/image:auth_supported=none:\

 mon_host=mon1.example.org\:6321\;mon2.example.org\:6322\;\

 mon3.example.org\:6322,if=virtio,format=raw' \

+-drive file=rbd:pool/image@asdf:auth_supported=none,if=virtio,format=raw \

+-drive 'file=rbd:pool/image@foo:auth_supported=none:\

+mon_host=mon1.example.org\:6321\;mon2.example.org\:6322\;\

+mon3.example.org\:6322,if=virtio,format=raw' \

 -net none -serial none -parallel none

diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-network-rbd.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-network-rbd.xml

index 37e9db5..f6accd8 100644

--- a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-network-rbd.xml

+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-network-rbd.xml

@@ -29,6 +29,23 @@

       </source>

       <target dev='vda' bus='virtio'/>

     </disk>

+    <disk type='network' device='disk'>

+      <driver name='qemu' type='raw'/>

+      <source protocol='rbd' name='pool/image'>

+        <snapshot name='asdf'/>

+      </source>

+      <target dev='vdb' bus='virtio'/>

+    </disk>

+    <disk type='network' device='disk'>

+      <driver name='qemu' type='raw'/>

+      <source protocol='rbd' name='pool/image'>

+        <host name='mon1.example.org' port='6321'/>

+        <host name='mon2.example.org' port='6322'/>

+        <host name='mon3.example.org' port='6322'/>

+        <snapshot name='foo'/>

+      </source>

+      <target dev='vdc' bus='virtio'/>

+    </disk>

     <controller type='usb' index='0'/>

     <controller type='ide' index='0'/>

     <controller type='pci' index='0' model='pci-root'/>

-- 

2.1.3