[Qemu-devel] [v6 Patch 1/4]Qemu: Enhance "info block" to display host cache setting

[Supriya Kannery <supriyak@linux.vnet.ibm.com>]

Enhance "info block" to display hostcache setting for each
block device.

Example:
(qemu) info block
ide0-hd0: type=hd removable=0 file=../rhel6-32.qcow2 ro=0 drv=qcow2
encrypted=0

Enhanced to display "hostcache" setting:
(qemu) info block
ide0-hd0: type=hd removable=0 hostcache=1 file=../rhel6-32.qcow2
ro=0 drv=qcow2 encrypted=0

Signed-off-by: Supriya Kannery <supriyak@linux.vnet.ibm.com>

---
 block.c         |   20 ++++++++++++++++----
 qmp-commands.hx |    2 ++
 2 files changed, 18 insertions(+), 4 deletions(-)

Index: qemu/block.c
===================================================================
--- qemu.orig/block.c
+++ qemu/block.c
@@ -1812,6 +1812,14 @@ static void bdrv_print_dict(QObject *obj
         monitor_printf(mon, " locked=%d", qdict_get_bool(bs_dict, "locked"));
     }
 
+    if (qdict_haskey(bs_dict, "open_flags")) {
+        int open_flags = qdict_get_int(bs_dict, "open_flags");
+        if (open_flags & BDRV_O_NOCACHE)
+            monitor_printf(mon, " hostcache=0");
+        else
+            monitor_printf(mon, " hostcache=1");
+    }
+
     if (qdict_haskey(bs_dict, "inserted")) {
         QDict *qdict = qobject_to_qdict(qdict_get(bs_dict, "inserted"));
 
@@ -1848,13 +1856,17 @@ void bdrv_info(Monitor *mon, QObject **r
         QObject *bs_obj;
 
         bs_obj = qobject_from_jsonf("{ 'device': %s, 'type': 'unknown', "
-                                    "'removable': %i, 'locked': %i }",
-                                    bs->device_name, bs->removable,
-                                    bs->locked);
+                                     "'removable': %i, 'locked': %i, "
+                                     "'hostcache': %i }",
+                                     bs->device_name, bs->removable,
+                                     bs->locked,
+                                     !(bs->open_flags & BDRV_O_NOCACHE));
+
+        QDict *bs_dict = qobject_to_qdict(bs_obj);
+        qdict_put(bs_dict, "open_flags", qint_from_int(bs->open_flags));
 
         if (bs->drv) {
             QObject *obj;
-            QDict *bs_dict = qobject_to_qdict(bs_obj);
 
             obj = qobject_from_jsonf("{ 'file': %s, 'ro': %i, 'drv': %s, "
                                      "'encrypted': %i }",
Index: qemu/qmp-commands.hx
===================================================================
--- qemu.orig/qmp-commands.hx
+++ qemu/qmp-commands.hx
@@ -1131,6 +1131,7 @@ Each json-object contain the following:
          - Possible values: "unknown"
 - "removable": true if the device is removable, false otherwise (json-bool)
 - "locked": true if the device is locked, false otherwise (json-bool)
+- "hostcache": true if host pagecache enabled, false otherwise (json-bool)
 - "inserted": only present if the device is inserted, it is a json-object
    containing the following:
          - "file": device file name (json-string)
@@ -1152,6 +1153,7 @@ Example:
          {
             "device":"ide0-hd0",
             "locked":false,
+            "hostcache":false,
             "removable":false,
             "inserted":{
                "ro":false,