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[Qemu-devel] [v1 Patch 3/10]Qemu: Cmd "block_set_hostcache" for dynamic
From: |
Supriya Kannery |
Subject: |
[Qemu-devel] [v1 Patch 3/10]Qemu: Cmd "block_set_hostcache" for dynamic cache change |
Date: |
Sat, 16 Jun 2012 02:17:30 +0530 |
New command "block_set_hostcache" added for dynamically changing
host pagecache setting of a block device.
Usage:
block_set_hostcache <device> <option>
<device> = block device
<option> = on/off
Example:
(qemu) block_set_hostcache ide0-hd0 off
Signed-off-by: Supriya Kannery <address@hidden>
---
block.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
block.h | 2 ++
blockdev.c | 26 ++++++++++++++++++++++++++
blockdev.h | 2 ++
hmp-commands.hx | 14 ++++++++++++++
qmp-commands.hx | 27 +++++++++++++++++++++++++++
6 files changed, 125 insertions(+)
Index: qemu/block.c
===================================================================
--- qemu.orig/block.c
+++ qemu/block.c
@@ -858,6 +858,35 @@ unlink_and_fail:
return ret;
}
+int bdrv_reopen(BlockDriverState *bs, int bdrv_flags)
+{
+ BlockDriver *drv = bs->drv;
+ int ret = 0, open_flags;
+
+ /* Quiesce IO for the given block device */
+ qemu_aio_flush();
+ ret = bdrv_flush(bs);
+ if (ret != 0) {
+ qerror_report(QERR_DATA_SYNC_FAILED, bs->device_name);
+ return ret;
+ }
+ open_flags = bs->open_flags;
+ bdrv_close(bs);
+
+ ret = bdrv_open(bs, bs->filename, bdrv_flags, drv);
+ if (ret < 0) {
+ /* Reopen failed. Try to open with original flags */
+ qerror_report(QERR_OPEN_FILE_FAILED, bs->filename);
+ ret = bdrv_open(bs, bs->filename, open_flags, drv);
+ if (ret < 0) {
+ /* Reopen failed with orig and modified flags */
+ abort();
+ }
+ }
+
+ return ret;
+}
+
void bdrv_close(BlockDriverState *bs)
{
bdrv_flush(bs);
@@ -953,6 +982,34 @@ void bdrv_drain_all(void)
}
}
+int bdrv_change_hostcache(BlockDriverState *bs, bool enable)
+{
+ int bdrv_flags = bs->open_flags;
+
+ /* set hostcache flags (without changing WCE/flush bits) */
+ if (enable) {
+ bdrv_flags &= ~BDRV_O_NOCACHE;
+ } else {
+ bdrv_flags |= BDRV_O_NOCACHE;
+ }
+
+ /* If no change in flags, no need to reopen */
+ if (bdrv_flags == bs->open_flags) {
+ printf("no need to change\n");
+ return 0;
+ }
+
+ if (bdrv_is_inserted(bs)) {
+ /* Reopen file with changed set of flags */
+ bdrv_flags &= ~BDRV_O_CACHE_WB;
+ return bdrv_reopen(bs, bdrv_flags);
+ } else {
+ /* Save hostcache change for future use */
+ bs->open_flags = bdrv_flags;
+ return 0;
+ }
+}
+
/* make a BlockDriverState anonymous by removing from bdrv_state list.
Also, NULL terminate the device_name to prevent double remove */
void bdrv_make_anon(BlockDriverState *bs)
Index: qemu/block.h
===================================================================
--- qemu.orig/block.h
+++ qemu/block.h
@@ -128,6 +128,7 @@ int bdrv_parse_cache_flags(const char *m
int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags);
int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
BlockDriver *drv);
+int bdrv_reopen(BlockDriverState *bs, int bdrv_flags);
void bdrv_close(BlockDriverState *bs);
int bdrv_attach_dev(BlockDriverState *bs, void *dev);
void bdrv_attach_dev_nofail(BlockDriverState *bs, void *dev);
@@ -177,6 +178,7 @@ int bdrv_commit_all(void);
int bdrv_change_backing_file(BlockDriverState *bs,
const char *backing_file, const char *backing_fmt);
void bdrv_register(BlockDriver *bdrv);
+int bdrv_change_hostcache(BlockDriverState *bs, bool enable_host_cache);
typedef struct BdrvCheckResult {
Index: qemu/blockdev.c
===================================================================
--- qemu.orig/blockdev.c
+++ qemu/blockdev.c
@@ -1198,3 +1198,27 @@ BlockJobInfoList *qmp_query_block_jobs(E
bdrv_iterate(do_qmp_query_block_jobs_one, &prev);
return dummy.next;
}
+
+
+/*
+ * Change host page cache setting while guest is running.
+*/
+void qmp_block_set_hostcache(const char *device, bool enable,
+ Error **errp)
+{
+ BlockDriverState *bs = NULL;
+
+ /* Validate device */
+ bs = bdrv_find(device);
+ if (!bs) {
+ error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+ return;
+ }
+
+ if (bdrv_change_hostcache(bs, enable)) {
+ error_set(errp, QERR_HOSTCACHE_NOT_CHANGED, device);
+ }
+
+ return;
+}
+
Index: qemu/hmp-commands.hx
===================================================================
--- qemu.orig/hmp-commands.hx
+++ qemu/hmp-commands.hx
@@ -808,7 +808,6 @@ ETEXI
.mhandler.cmd = hmp_migrate,
},
-
STEXI
@item migrate [-d] [-b] [-i] @var{uri}
@findex migrate
@@ -1314,6 +1313,21 @@ client. @var{keep} changes the password
ETEXI
{
+ .name = "block_set_hostcache",
+ .args_type = "device:B,option:b",
+ .params = "device on|off",
+ .help = "Change setting of host pagecache",
+ .mhandler.cmd = hmp_block_set_hostcache,
+ },
+
+STEXI
address@hidden block_set_hostcache @var{device} @var{option}
address@hidden block_set_hostcache
+Change host pagecache setting of a block device while guest is running.
+ETEXI
+
+
+ {
.name = "expire_password",
.args_type = "protocol:s,time:s",
.params = "protocol time",
Index: qemu/qmp-commands.hx
===================================================================
--- qemu.orig/qmp-commands.hx
+++ qemu/qmp-commands.hx
@@ -821,7 +821,31 @@ Example:
EQMP
+
{
+ .name = "block_set_hostcache",
+ .args_type = "device:B,option:b",
+ .mhandler.cmd_new = qmp_block_set_hostcache,
+ },
+
+SQMP
+block_set_hostcache
+-------------------
+
+Change host pagecache setting of a block device
+
+Arguments:
+
+- "device": the device's ID, must be unique (json-string)
+- "option": hostcache setting (json-bool)
+
+Example:
+-> { "execute": "block_set_hostcache", "arguments": { "device": "ide0-hd0",
"option": false } }
+<- { "return": {} }
+
+EQMP
+
+ {
.name = "balloon",
.args_type = "value:M",
.mhandler.cmd_new = qmp_marshal_input_balloon,
Index: qemu/qapi-schema.json
===================================================================
--- qemu.orig/qapi-schema.json
+++ qemu/qapi-schema.json
@@ -1598,6 +1598,22 @@
{ 'command': 'block_set_io_throttle',
'data': { 'device': 'str', 'bps': 'int', 'bps_rd': 'int', 'bps_wr': 'int',
'iops': 'int', 'iops_rd': 'int', 'iops_wr': 'int' } }
+##
+# @block_set_hostcache:
+#
+# Change host pagecache setting of a block device
+#
+# @device: name of the block device
+#
+# @option: hostcache setting (true/false)
+#
+# Returns: Nothing on success
+# If @device is not a valid block device, DeviceNotFound
+#
+# Since: 1.2
+##
+{ 'command': 'block_set_hostcache',
+ 'data': { 'device': 'str', 'option': 'bool' } }
##
# @block-stream:
Index: qemu/hmp.c
===================================================================
--- qemu.orig/hmp.c
+++ qemu/hmp.c
@@ -836,6 +836,15 @@ void hmp_block_set_io_throttle(Monitor *
hmp_handle_error(mon, &err);
}
+void hmp_block_set_hostcache(Monitor *mon, const QDict *qdict)
+{
+ Error *err = NULL;
+
+ qmp_block_set_hostcache(qdict_get_str(qdict, "device"),
+ qdict_get_bool(qdict, "option"), &err);
+ hmp_handle_error(mon, &err);
+}
+
void hmp_block_stream(Monitor *mon, const QDict *qdict)
{
Error *error = NULL;
Index: qemu/hmp.h
===================================================================
--- qemu.orig/hmp.h
+++ qemu/hmp.h
@@ -64,5 +64,6 @@ void hmp_device_del(Monitor *mon, const
void hmp_dump_guest_memory(Monitor *mon, const QDict *qdict);
void hmp_netdev_add(Monitor *mon, const QDict *qdict);
void hmp_netdev_del(Monitor *mon, const QDict *qdict);
+void hmp_block_set_hostcache(Monitor *mon, const QDict *qdict);
#endif
- [Qemu-devel] [v1 Patch 0/10]Qemu: Dynamic host pagecache change and image file reopen, Supriya Kannery, 2012/06/15
- [Qemu-devel] [v1 Patch 1/10]Qemu: Enhance "info block" to display host cache setting, Supriya Kannery, 2012/06/15
- [Qemu-devel] [v1 Patch 3/10]Qemu: Cmd "block_set_hostcache" for dynamic cache change,
Supriya Kannery <=
- [Qemu-devel] [v1 Patch 4/10]Qemu: Framework for reopening image files safely, Supriya Kannery, 2012/06/15
- [Qemu-devel] [v1 Patch 2/10]Qemu: Error classes for hostcache setting and data sync failures, Supriya Kannery, 2012/06/15
- [Qemu-devel] [v1 Patch 6/10]Qemu: raw-win32 image file reopen, Supriya Kannery, 2012/06/15
- [Qemu-devel] [v1 Patch 5/10]Qemu: raw-posix image file reopen, Supriya Kannery, 2012/06/15
- [Qemu-devel] [v1 Patch 7/10]Qemu: vmdk image file reopen, Supriya Kannery, 2012/06/15
- [Qemu-devel] [v1 Patch 8/10]Qemu: qcow2 image file reopen, Supriya Kannery, 2012/06/15