[libvirt] [PATCH 3/3] virsh: Allow display of the physical volume size

[John Ferlan]

Add a new qualifier '--physical' to the 'vol-info' command in order to
dispaly the physical size of the volume. The size can differ from the
allocation value depending on the volume file time. In particular, qcow2
volumes will have a physical value larger than allocation. This also occurs
for sparse files, although for those the capacity is the largest size;
whereas, for qcow2 capacity is the logical size.

Signed-off-by: John Ferlan <jferlan at redhat.com>
---
 tools/virsh-volume.c | 37 +++++++++++++++++++++++++++++++++----
 tools/virsh.pod      |  8 ++++++--
 2 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/tools/virsh-volume.c b/tools/virsh-volume.c
index 96b4a7b..f702627 100644
--- a/tools/virsh-volume.c
+++ b/tools/virsh-volume.c
@@ -996,6 +996,10 @@ static const vshCmdOptDef opts_vol_info[] = {
      .type = VSH_OT_BOOL,
      .help = N_("sizes are represented in bytes rather than pretty units")
     },
+    {.name = "physical",
+     .type = VSH_OT_BOOL,
+     .help = N_("return the physical size of the volume in allocation field")
+    },
     {.name = NULL}
 };
 
@@ -1005,14 +1009,32 @@ cmdVolInfo(vshControl *ctl, const vshCmd *cmd)
     virStorageVolInfo info;
     virStorageVolPtr vol;
     bool bytes = vshCommandOptBool(cmd, "bytes");
+    bool physical = vshCommandOptBool(cmd, "physical");
     bool ret = true;
+    int rc;
+    unsigned int flags = 0;
 
     if (!(vol = virshCommandOptVol(ctl, cmd, "vol", "pool", NULL)))
         return false;
 
     vshPrint(ctl, "%-15s %s\n", _("Name:"), virStorageVolGetName(vol));
 
-    if (virStorageVolGetInfo(vol, &info) == 0) {
+    if (physical)
+        flags |= VIR_STORAGE_VOL_GET_PHYSICAL;
+
+    if (flags) {
+        if ((rc = virStorageVolGetInfoFlags(vol, &info, flags)) < 0) {
+            flags = 0;
+            if (last_error->code == VIR_ERR_NO_SUPPORT) {
+                vshResetLibvirtError();
+                rc = virStorageVolGetInfo(vol, &info);
+            }
+        }
+    } else {
+        rc = virStorageVolGetInfo(vol, &info);
+    }
+
+    if (rc == 0) {
         double val;
         const char *unit;
 
@@ -1028,11 +1050,18 @@ cmdVolInfo(vshControl *ctl, const vshCmd *cmd)
         }
 
         if (bytes) {
-            vshPrint(ctl, "%-15s %llu %s\n", _("Allocation:"),
-                     info.allocation, _("bytes"));
+            if (physical)
+                vshPrint(ctl, "%-15s %llu %s\n", _("Physical:"),
+                         info.allocation, _("bytes"));
+            else
+                vshPrint(ctl, "%-15s %llu %s\n", _("Allocation:"),
+                         info.allocation, _("bytes"));
          } else {
             val = vshPrettyCapacity(info.allocation, &unit);
-            vshPrint(ctl, "%-15s %2.2lf %s\n", _("Allocation:"), val, unit);
+            if (physical)
+                vshPrint(ctl, "%-15s %2.2lf %s\n", _("Physical:"), val, unit);
+            else
+                vshPrint(ctl, "%-15s %2.2lf %s\n", _("Allocation:"), val, unit);
          }
     } else {
         ret = false;
diff --git a/tools/virsh.pod b/tools/virsh.pod
index 74c05c9..f606f4f 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -3862,13 +3862,17 @@ is in. I<vol-name-or-key-or-path> is the name or key or path of the volume
 to output the XML of.
 
 =item B<vol-info> [I<--pool> I<pool-or-uuid>] I<vol-name-or-key-or-path>
-[I<--bytes>]
+[I<--bytes>] [I<--physical>]
 
 Returns basic information about the given storage volume.
 I<--pool> I<pool-or-uuid> is the name or UUID of the storage pool the volume
 is in. I<vol-name-or-key-or-path> is the name or key or path of the volume
 to return information for. If I<--bytes> is specified the sizes are not
-converted to human friendly units.
+converted to human friendly units. If I<--physical> is specified, then the host
+physical size is returned and displayed instead of the allocation value. The
+physical value for some file types, such as qcow2 may have a different (larger)
+physical value than is shown for allocation. Additionally sparse files will
+have different physical and allocation values.
 
 =item B<vol-list> [I<--pool> I<pool-or-uuid>] [I<--details>]
 
-- 
2.7.4