[Qemu-devel] [libvirt patch] qemu: adds support for virtfs 9p argument 'vii'

[Christian Schoenebeck via Qemu-devel <qemu-devel@nongnu.org>]

This is the counter part patch against latest libvirt git master head to
support the 'vii' feature of patch 5, which introduces the XML config
XML tag "important" on libvirt side.

To stick with the previous example mentioned with patch 5, likewise
libvirt XML configuration might then look like this:

  <domain type='kvm'>
    ...
    <devices>
      ...
      <filesystem type='mount' accessmode='mapped'>
        <source dir='/vm/fs'/>
        <target dir='root'/>
        <important path='/var/shares'/>
        <important path='/tmp'/>
      </filesystem>
    </devices>
  </domain>

Like with the vii qemu virtfs command line argument, the order of the
"important" tag defines which one gets the highest inode namespace
(smallest generated suffix) on guest side.

Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
---
 docs/schemas/domaincommon.rng |  6 ++++++
 src/conf/domain_conf.c        | 30 ++++++++++++++++++++++++++++++
 src/conf/domain_conf.h        |  3 +++
 src/qemu/qemu_command.c       | 10 ++++++++++
 4 files changed, 49 insertions(+)

diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 111b85c36f..c75edfc4d3 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -2515,6 +2515,12 @@
             </choice>
           </attribute>
         </optional>
+        <zeroOrMore>
+          <element name='important'>
+            <attribute name="path"/>
+            <empty/>
+          </element>
+        </zeroOrMore>
         <optional>
           <element name='readonly'>
             <empty/>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index b4fb6cf981..cc75c6a7dd 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -2294,6 +2294,8 @@ virDomainFSDefNew(void)
 
 void virDomainFSDefFree(virDomainFSDefPtr def)
 {
+    size_t i;
+
     if (!def)
         return;
 
@@ -2302,6 +2304,13 @@ void virDomainFSDefFree(virDomainFSDefPtr def)
     virDomainDeviceInfoClear(&def->info);
     VIR_FREE(def->virtio);
 
+    if (def->important) {
+        for (i = 0; i < def->nimportant; i++)
+            if (def->important[i])
+                VIR_FREE(def->important[i]);
+    }
+    VIR_FREE(def->important);
+
     VIR_FREE(def);
 }
 
@@ -10953,6 +10962,7 @@ virDomainFSDefParseXML(virDomainXMLOptionPtr xmlopt,
     VIR_AUTOFREE(char *) usage = NULL;
     VIR_AUTOFREE(char *) units = NULL;
     VIR_AUTOFREE(char *) model = NULL;
+    long n;
 
     ctxt->node = node;
 
@@ -11001,6 +11011,12 @@ virDomainFSDefParseXML(virDomainXMLOptionPtr xmlopt,
                                   1, ULLONG_MAX, false) < 0)
         goto error;
 
+    n = virXMLChildElementCount(node);
+    if (n > 0) {
+        if (VIR_ALLOC_N(def->important, n) < 0)
+            goto error;
+    }
+
     cur = node->children;
     while (cur != NULL) {
         if (cur->type == XML_ELEMENT_NODE) {
@@ -11039,6 +11055,8 @@ virDomainFSDefParseXML(virDomainXMLOptionPtr xmlopt,
 
                 if (virDomainVirtioOptionsParseXML(cur, &def->virtio) < 0)
                     goto error;
+            } else if (virXMLNodeNameEqual(cur, "important")) {
+                def->important[def->nimportant++] = virXMLPropString(cur, "path");
             }
         }
         cur = cur->next;
@@ -11107,6 +11125,8 @@ virDomainFSDefParseXML(virDomainXMLOptionPtr xmlopt,
         goto error;
 
  cleanup:
+    if (def && def->important && !def->nimportant)
+        VIR_FREE(def->important);
     return def;
 
  error:
@@ -24601,6 +24621,7 @@ virDomainFSDefFormat(virBufferPtr buf,
     const char *src = def->src->path;
     VIR_AUTOCLEAN(virBuffer) driverBuf = VIR_BUFFER_INITIALIZER;
     int ret = -1;
+    size_t i;
 
     if (!type) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
@@ -24689,6 +24710,15 @@ virDomainFSDefFormat(virBufferPtr buf,
     if (def->readonly)
         virBufferAddLit(buf, "<readonly/>\n");
 
+    if (def->important) {
+        for (i = 0; i < def->nimportant; ++i) {
+            if (!def->important[i]) continue;
+            virBufferAddLit(buf, "<important");
+            virBufferEscapeString(buf, " path='%s'", def->important[i]);
+            virBufferAddLit(buf, "/>\n");
+        }
+    }
+
     if (virDomainDeviceInfoFormat(buf, &def->info, flags) < 0)
         goto cleanup;
 
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 01c22d8cc3..9bbd66d932 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -818,6 +818,9 @@ struct _virDomainFSDef {
     unsigned long long space_soft_limit; /* in bytes */
     bool symlinksResolved;
     virDomainVirtioOptionsPtr virtio;
+
+    size_t nimportant;
+    char **important;
 };
 
 
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 50b4205267..2005ccadf8 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -2732,6 +2732,7 @@ qemuBuildFSStr(virDomainFSDefPtr fs)
     virBuffer opt = VIR_BUFFER_INITIALIZER;
     const char *driver = qemuDomainFSDriverTypeToString(fs->fsdriver);
     const char *wrpolicy = virDomainFSWrpolicyTypeToString(fs->wrpolicy);
+    size_t i;
 
     if (fs->type != VIR_DOMAIN_FS_TYPE_MOUNT) {
         virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
@@ -2775,6 +2776,15 @@ qemuBuildFSStr(virDomainFSDefPtr fs)
     if (fs->readonly)
         virBufferAddLit(&opt, ",readonly");
 
+    if (fs->important) {
+        for (i = 0; i < fs->nimportant; ++i) {
+            if (i == 0)
+                virBufferAsprintf(&opt, ",vii=%s", fs->important[i]);
+            else
+                virBufferAsprintf(&opt, ":%s", fs->important[i]);
+        }
+    }
+
     if (virBufferCheckError(&opt) < 0)
         goto error;
 
-- 
2.11.0