The disk cache mode translates to various frontend and backend
attributes for the qemu block layer. For the frontend device the
'writeback' parameter is used and provided as 'write-cache'. Implement
this so that we can later switch to using -blockdev where we will not
pass the cachemode directly any more.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
---
src/qemu/qemu_command.c | 27 ++++++++++++++++++++++
.../disk-drive-write-cache.new.args | 10 ++++----
2 files changed, 33 insertions(+), 4 deletions(-)
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index a1a9e91e49..08c6e4faac 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -1822,6 +1822,30 @@ qemuCheckIOThreads(const virDomainDef *def,
}
+static int
+qemuBuildDriveDevCacheStr(virDomainDiskDefPtr disk,
+ virBufferPtr buf,
+ virQEMUCapsPtr qemuCaps)
+{
+ bool wb;
+
+ if (disk->cachemode == VIR_DOMAIN_DISK_CACHE_DEFAULT)
+ return 0;
+
+ if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_DISK_WRITE_CACHE))
+ return 0;
+
+ if (qemuDomainDiskCachemodeFlags(disk->cachemode, &wb, NULL, NULL) < 0)
+ return -1;
+
+ virBufferStrcat(buf, ",write-cache=",
+ virTristateSwitchTypeToString(virTristateSwitchFromBool(wb)),
+ NULL);
+
+ return 0;
+}
+
+
char *
qemuBuildDriveDevStr(const virDomainDef *def,
virDomainDiskDefPtr disk,
@@ -2134,6 +2158,9 @@ qemuBuildDriveDevStr(const virDomainDef *def,
}
}
+ if (qemuBuildDriveDevCacheStr(disk, &opt, qemuCaps) < 0)
+ goto error;
+
if (virBufferCheckError(&opt) < 0)
goto error;
diff --git a/tests/qemuxml2argvdata/disk-drive-write-cache.new.args b/tests/qemuxml2argvdata/disk-drive-write-cache.new.args
index 90414a100f..3973249d18 100644
--- a/tests/qemuxml2argvdata/disk-drive-write-cache.new.args
+++ b/tests/qemuxml2argvdata/disk-drive-write-cache.new.args
@@ -28,16 +28,18 @@ server,nowait \
-device lsi,id=scsi0,bus=pci.0,addr=0x2 \
-drive file=/dev/HostVG/QEMUGuest1,format=qcow2,if=none,id=drive-ide0-0-0,\
cache=writeback \
--device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 \
+-device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1,\
+write-cache=on \
-drive file=/dev/HostVG/QEMUGuest1,format=qcow2,if=none,id=drive-scsi0-0-0,\
cache=none \
--device scsi-hd,bus=scsi0.0,scsi-id=0,drive=drive-scsi0-0-0,id=scsi0-0-0 \
+-device scsi-hd,bus=scsi0.0,scsi-id=0,drive=drive-scsi0-0-0,id=scsi0-0-0,\
+write-cache=on \
-drive file=/dev/HostVG/QEMUGuest1,format=qcow2,if=none,id=drive-virtio-disk0,\
cache=writethrough \
-device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x3,drive=drive-virtio-disk0,\
-id=virtio-disk0 \
+id=virtio-disk0,write-cache=off \
-drive file=/dev/HostVG/QEMUGuest1,format=qcow2,if=none,id=drive-usb-disk1,\
cache=directsync \
-device usb-storage,bus=usb.0,port=1,drive=drive-usb-disk1,id=usb-disk1,\
-removable=off \
+removable=off,write-cache=off \
-msg timestamp=on
--
2.16.2
--
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