[libvirt] [PATCH] Added snapshot backing store parameters to virsh vol-create-as.

[Justin Clift]

---
  tools/virsh.c   |   52 
+++++++++++++++++++++++++++++++++++++++++++++++++++-
  tools/virsh.pod |    7 ++++++-
  2 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/tools/virsh.c b/tools/virsh.c
index 1279f41..3ba549b 100644
--- a/tools/virsh.c
+++ b/tools/virsh.c
@@ -5274,6 +5274,8 @@ static const vshCmdOptDef opts_vol_create_as[] = {
      {"capacity", VSH_OT_DATA, VSH_OFLAG_REQ, N_("size of the vol with 
optional k,M,G,T suffix")},
      {"allocation", VSH_OT_STRING, 0, N_("initial allocation size with 
optional k,M,G,T suffix")},
      {"format", VSH_OT_STRING, 0, N_("file format type 
raw,bochs,qcow,qcow2,vmdk")},
+    {"snapshot-source-vol", VSH_OT_STRING, 0, N_("the source volume if 
taking a snapshot")},
+    {"snapshot-source-format", VSH_OT_STRING, 0, N_("format of the 
source volume if taking a snapshot")},
      {NULL, 0, 0, NULL}
  };
  @@ -5313,6 +5315,7 @@ cmdVolCreateAs(vshControl *ctl, const vshCmd *cmd)
      int found;
      char *xml;
      char *name, *capacityStr, *allocationStr, *format;
+    char *snapshotStrVol, *snapshotStrFormat;
      unsigned long long capacity, allocation = 0;
      virBuffer buf = VIR_BUFFER_INITIALIZER;
  @@ -5339,6 +5342,8 @@ cmdVolCreateAs(vshControl *ctl, const vshCmd *cmd)
          vshError(ctl, _("Malformed size %s"), allocationStr);
       format = vshCommandOptString(cmd, "format", &found);
+    snapshotStrVol = vshCommandOptString(cmd, "snapshot-source-vol", 
&found);
+    snapshotStrFormat = vshCommandOptString(cmd, 
"snapshot-source-format", &found);
       virBufferAddLit(&buf, "<volume>\n");
      virBufferVSprintf(&buf, "  <name>%s</name>\n", name);
@@ -5351,8 +5356,53 @@ cmdVolCreateAs(vshControl *ctl, const vshCmd *cmd)
          virBufferVSprintf(&buf, "    <format type='%s'/>\n",format);
          virBufferAddLit(&buf, "  </target>\n");
      }
-    virBufferAddLit(&buf, "</volume>\n");
  +    // Convert the snapshot parameters into backingStore XML
+    if (snapshotStrVol) {
+        // Use the name of the snapshot source volume to retrieve its 
device path
+        vshDebug(ctl, 5, "%s: Looking up backing store volume '%s' as 
name\n", cmd->def->name, snapshotStrVol);
+        virStorageVolPtr snapVol = virStorageVolLookupByName(pool, 
snapshotStrVol);
+        if (snapVol)
+                vshDebug(ctl, 5, "%s: Backing store volume found using 
'%s' as name\n", cmd->def->name, snapshotStrVol);
+
+        if (snapVol == NULL) {
+            // Snapshot source volume was not found by name.  Try using 
the snapshot-source-vol parameter as a key
+            vshDebug(ctl, 5, "%s: Looking up backing store volume '%s' 
as key\n", cmd->def->name, snapshotStrVol);
+            snapVol = virStorageVolLookupByKey(ctl->conn, snapshotStrVol);
+            if (snapVol)
+                vshDebug(ctl, 5, "%s: Backing store volume found using 
'%s' as key\n", cmd->def->name, snapshotStrVol);
+        }
+        if (snapVol == NULL) {
+            // Snapshot source volume was not found by key either.  Try 
using the snapshot-source-vol parameter as a path
+            vshDebug(ctl, 5, "%s: Looking up backing store volume '%s' 
by path\n", cmd->def->name, snapshotStrVol);
+            snapVol = virStorageVolLookupByPath(ctl->conn, snapshotStrVol);
+            if (snapVol)
+                vshDebug(ctl, 5, "%s: Backing store volume found using 
'%s' as path\n", cmd->def->name, snapshotStrVol);
+        }
+        if (snapVol == NULL) {
+            vshError(ctl, _("failed to get vol '%s'"), snapshotStrVol);
+            return FALSE;
+        }
+
+        char *snapshotStrVolPath;
+        if ((snapshotStrVolPath = virStorageVolGetPath(snapVol)) == NULL) {
+            virStorageVolFree(snapVol);
+            return FALSE;
+        }
+
+        // Create the XML for the backing store
+        virBufferAddLit(&buf, "  <backingStore>\n");
+        virBufferVSprintf(&buf, " 
<path>%s</path>\n",snapshotStrVolPath);
+        if (snapshotStrFormat)
+            virBufferVSprintf(&buf, "    <format 
type='%s'/>\n",snapshotStrFormat);
+        virBufferAddLit(&buf, "  </backingStore>\n");
+
+        // Cleanup snapshot allocations
+        VIR_FREE(snapshotStrVolPath);
+        virStorageVolFree(snapVol);
+    }
+
+    virBufferAddLit(&buf, "</volume>\n");
       if (virBufferError(&buf)) {
          vshPrint(ctl, "%s", _("Failed to allocate XML buffer"));
diff --git a/tools/virsh.pod b/tools/virsh.pod
index cab931c..b1a8544 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -782,7 +782,8 @@ source volume is in.
  I<vol-name-or-key> is the name or UUID of the source volume.
   =item B<vol-create-as> I<pool-or-uuid> I<name> I<capacity> optional
-I<--allocation> I<size> I<--format> I<string>
+I<--allocation> I<size> I<--format> I<string> I<--snapshot-source-vol> 
I<vol-name-or-key>
+I<--snapshot-source-format> I<string>
   Create a volume from a set of arguments.
  I<pool-or-uuid> is the name or UUID of the storage pool to create the 
volume
@@ -794,6 +795,10 @@ I<--allocation> I<size> is the initial size to be 
allocated in the volume, with
  optional k, M, G, or T suffix.
  I<--format> I<string> is used in file based storage pools to specify 
the volume
  file format to use; raw, bochs, qcow, qcow2, vmdk.
+I<--snapshot-source-vol> I<vol-name-or-key> is the source backing 
volume to be used if
+taking a snapshot of an existing volume.
+I<--snapshot-source-format> I<string> is the format of the snapshot 
backing volume;
+raw, bochs, qcow, qcow2, vmdk.
   =item B<vol-clone> [optional I<--pool> I<pool-or-uuid>] 
I<vol-name-or-key> I<name>
  -- 1.7.0.1