new attribute accessmode to filesystem element

This introduces new attribute to filesystem element
to support customizable access mode for mount type.
Valid accessmode are: passthrough, mapped and squash.

Usage:
        <filesystem type='mount' accessmode='passthrough'>
          <source dir='/export/to/guest'/>
          <target dir='mount_tag'/>
        </filesystem>

passthrough is the default model if not specified, that's
also the current behaviour.

.gnulib @ 2bb63bfb

-Subproject commit b6d1430494cdd252cd52eca6abf88b1a00f6c983
+Subproject commit 2bb63bfb25474ea147ee9f1523c0337997359a4c

docs/schemas/domain.rng

@@ -794,6 +794,13 @@
       </choice>
       <optional>
         <ref name="address"/>
+        <attribute name="accessmode">
+        <choice>
+          <value>passthrough</value>
+          <value>mapped</value>
+          <value>squash</value>
+        </choice>
+        </attribute>
       </optional>
     </element>
   </define>

src/conf/domain_conf.c

@@ -161,6 +161,12 @@ VIR_ENUM_IMPL(virDomainFS, VIR_DOMAIN_FS_TYPE_LAST,
               "file",
               "template")
 
+VIR_ENUM_IMPL(virDomainFSAccessMode, VIR_DOMAIN_FS_ACCESSMODE_LAST,
+              "passthrough",
+              "mapped",
+              "squash")
+
+
 VIR_ENUM_IMPL(virDomainNet, VIR_DOMAIN_NET_TYPE_LAST,
               "user",
               "ethernet",
@@ -1853,6 +1859,7 @@ virDomainFSDefParseXML(xmlNodePtr node,
     char *type = NULL;
     char *source = NULL;
     char *target = NULL;
+    char *accessmode = NULL;
 
     if (VIR_ALLOC(def) < 0) {
         virReportOOMError();
@@ -1870,6 +1877,17 @@ virDomainFSDefParseXML(xmlNodePtr node,
         def->type = VIR_DOMAIN_FS_TYPE_MOUNT;
     }
 
+    accessmode = virXMLPropString(node, "accessmode");
+    if (accessmode) {
+        if ((def->accessmode = virDomainFSAccessModeTypeFromString(accessmode)) < 0) {
+            virDomainReportError(VIR_ERR_INTERNAL_ERROR,
+                                 _("unknown accessmode '%s'"), accessmode);
+            goto error;
+        }
+    } else {
+        def->accessmode = VIR_DOMAIN_FS_ACCESSMODE_PASSTHROUGH;
+    }
+
     cur = node->children;
     while (cur != NULL) {
         if (cur->type == XML_ELEMENT_NODE) {
@@ -1918,6 +1936,7 @@ cleanup:
     VIR_FREE(type);
     VIR_FREE(target);
     VIR_FREE(source);
+    VIR_FREE(accessmode);
 
     return def;
 
@@ -5625,6 +5644,7 @@ virDomainFSDefFormat(virBufferPtr buf,
                      int flags)
 {
     const char *type = virDomainFSTypeToString(def->type);
+    const char *accessmode = virDomainFSAccessModeTypeToString(def->accessmode);
 
     if (!type) {
         virDomainReportError(VIR_ERR_INTERNAL_ERROR,
@@ -5632,9 +5652,16 @@ virDomainFSDefFormat(virBufferPtr buf,
         return -1;
     }
 
+   if (!accessmode) {
+        virDomainReportError(VIR_ERR_INTERNAL_ERROR,
+                             _("unexpected accessmode %d"), def->accessmode);
+        return -1;
+    }
+
+
     virBufferVSprintf(buf,
-                      "    <filesystem type='%s'>\n",
-                      type);
+                      "    <filesystem type='%s' accessmode='%s'>\n",
+                      type, accessmode);
 
     if (def->src) {
         switch (def->type) {

src/conf/domain_conf.h

@@ -236,10 +236,20 @@ enum virDomainFSType {
     VIR_DOMAIN_FS_TYPE_LAST
 };
 
+/* Filesystem mount access mode  */
+enum virDomainFSAccessMode {
+    VIR_DOMAIN_FS_ACCESSMODE_PASSTHROUGH,
+    VIR_DOMAIN_FS_ACCESSMODE_MAPPED,
+    VIR_DOMAIN_FS_ACCESSMODE_SQUASH,
+
+    VIR_DOMAIN_FS_ACCESSMODE_LAST
+};
+
 typedef struct _virDomainFSDef virDomainFSDef;
 typedef virDomainFSDef *virDomainFSDefPtr;
 struct _virDomainFSDef {
     int type;
+    int accessmode;
     char *src;
     char *dst;
     unsigned int readonly : 1;
@@ -1175,6 +1185,7 @@ VIR_ENUM_DECL(virDomainDiskErrorPolicy)
 VIR_ENUM_DECL(virDomainController)
 VIR_ENUM_DECL(virDomainControllerModel)
 VIR_ENUM_DECL(virDomainFS)
+VIR_ENUM_DECL(virDomainFSAccessMode)
 VIR_ENUM_DECL(virDomainNet)
 VIR_ENUM_DECL(virDomainChrDevice)
 VIR_ENUM_DECL(virDomainChrChannelTarget)

src/qemu/qemu_conf.c

@@ -2789,11 +2789,18 @@ char *qemuBuildFSStr(virDomainFSDefPtr fs,
 
     if (fs->type != VIR_DOMAIN_FS_TYPE_MOUNT) {
         qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
-                        _("can only passthrough directories"));
+                        _("only supports mount filesystem type"));
         goto error;
     }
 
-    virBufferAddLit(&opt, "local,security_model=passthrough");
+    virBufferAddLit(&opt, "local");
+    if (fs->accessmode == VIR_DOMAIN_FS_ACCESSMODE_MAPPED) {
+        virBufferAddLit(&opt, ",security_model=mapped");
+    } else if(fs->accessmode == VIR_DOMAIN_FS_ACCESSMODE_PASSTHROUGH) {
+        virBufferAddLit(&opt, ",security_model=passthrough");
+    } else if(fs->accessmode == VIR_DOMAIN_FS_ACCESSMODE_SQUASH) {
+        virBufferAddLit(&opt, ",security_model=none");
+    }
     virBufferVSprintf(&opt, ",id=%s%s", QEMU_FSDEV_HOST_PREFIX, fs->info.alias);
     virBufferVSprintf(&opt, ",path=%s", fs->src);