From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To: qemu-block@nongnu.org
Cc: qemu-devel@nongnu.org, vsementsov@virtuozzo.com,
jsnow@redhat.com, mreitz@redhat.com, kwolf@redhat.com,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Daniel P. Berrangé" <berrange@redhat.com>,
"Eduardo Habkost" <ehabkost@redhat.com>
Subject: [PATCH v5 06/35] qdev: allow setting drive property for realized device
Date: Thu, 10 Jun 2021 14:25:49 +0300 [thread overview]
Message-ID: <20210610112618.127378-7-vsementsov@virtuozzo.com> (raw)
In-Reply-To: <20210610112618.127378-1-vsementsov@virtuozzo.com>
We need an ability to insert filters above top block node, attached to
block device. It can't be achieved with blockdev-reopen command. So, we
want do it with help of qom-set.
Intended usage:
Assume there is a node A that is attached to some guest device.
1. blockdev-add to create a filter node B that has A as its child.
2. qom-set to change the node attached to the guest device’s
BlockBackend from A to B.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
hw/core/qdev-properties-system.c | 43 +++++++++++++++++++++++---------
1 file changed, 31 insertions(+), 12 deletions(-)
diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
index 2760c21f11..e71f5d64d1 100644
--- a/hw/core/qdev-properties-system.c
+++ b/hw/core/qdev-properties-system.c
@@ -36,11 +36,11 @@
static bool check_prop_still_unset(Object *obj, const char *name,
const void *old_val, const char *new_val,
- Error **errp)
+ bool allow_override, Error **errp)
{
const GlobalProperty *prop = qdev_find_global_prop(obj, name);
- if (!old_val) {
+ if (!old_val || (!prop && allow_override)) {
return true;
}
@@ -93,16 +93,34 @@ static void set_drive_helper(Object *obj, Visitor *v, const char *name,
BlockBackend *blk;
bool blk_created = false;
int ret;
+ BlockDriverState *bs;
+ AioContext *ctx;
if (!visit_type_str(v, name, &str, errp)) {
return;
}
- /*
- * TODO Should this really be an error? If no, the old value
- * needs to be released before we store the new one.
- */
- if (!check_prop_still_unset(obj, name, *ptr, str, errp)) {
+ if (!check_prop_still_unset(obj, name, *ptr, str, true, errp)) {
+ return;
+ }
+
+ if (*ptr) {
+ /* BlockBackend alread exists. So, we want to change attached node */
+ blk = *ptr;
+ ctx = blk_get_aio_context(blk);
+ bs = bdrv_lookup_bs(NULL, str, errp);
+ if (!bs) {
+ return;
+ }
+
+ if (ctx != bdrv_get_aio_context(bs)) {
+ error_setg(errp, "Different aio context is not supported for new "
+ "node");
+ }
+
+ aio_context_acquire(ctx);
+ blk_replace_bs(blk, bs, errp);
+ aio_context_release(ctx);
return;
}
@@ -114,7 +132,7 @@ static void set_drive_helper(Object *obj, Visitor *v, const char *name,
blk = blk_by_name(str);
if (!blk) {
- BlockDriverState *bs = bdrv_lookup_bs(NULL, str, NULL);
+ bs = bdrv_lookup_bs(NULL, str, NULL);
if (bs) {
/*
* If the device supports iothreads, it will make sure to move the
@@ -123,8 +141,7 @@ static void set_drive_helper(Object *obj, Visitor *v, const char *name,
* aware of iothreads require their BlockBackends to be in the main
* AioContext.
*/
- AioContext *ctx = iothread ? bdrv_get_aio_context(bs) :
- qemu_get_aio_context();
+ ctx = iothread ? bdrv_get_aio_context(bs) : qemu_get_aio_context();
blk = blk_new(ctx, 0, BLK_PERM_ALL);
blk_created = true;
@@ -196,6 +213,7 @@ static void release_drive(Object *obj, const char *name, void *opaque)
const PropertyInfo qdev_prop_drive = {
.name = "str",
.description = "Node name or ID of a block device to use as a backend",
+ .realized_set_allowed = true,
.get = get_drive,
.set = set_drive,
.release = release_drive,
@@ -204,6 +222,7 @@ const PropertyInfo qdev_prop_drive = {
const PropertyInfo qdev_prop_drive_iothread = {
.name = "str",
.description = "Node name or ID of a block device to use as a backend",
+ .realized_set_allowed = true,
.get = get_drive,
.set = set_drive_iothread,
.release = release_drive,
@@ -238,7 +257,7 @@ static void set_chr(Object *obj, Visitor *v, const char *name, void *opaque,
* TODO Should this really be an error? If no, the old value
* needs to be released before we store the new one.
*/
- if (!check_prop_still_unset(obj, name, be->chr, str, errp)) {
+ if (!check_prop_still_unset(obj, name, be->chr, str, false, errp)) {
return;
}
@@ -408,7 +427,7 @@ static void set_netdev(Object *obj, Visitor *v, const char *name,
* TODO Should this really be an error? If no, the old value
* needs to be released before we store the new one.
*/
- if (!check_prop_still_unset(obj, name, ncs[i], str, errp)) {
+ if (!check_prop_still_unset(obj, name, ncs[i], str, false, errp)) {
goto out;
}
--
2.29.2
next prev parent reply other threads:[~2021-06-10 11:37 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-10 11:25 [PATCH v5 00/35] block: publish backup-top filter Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 01/35] block: rename bdrv_replace_child to bdrv_replace_child_tran Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 02/35] block: comment graph-modifying function not updating permissions Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 03/35] block: introduce bdrv_replace_child_bs() Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 04/35] block: introduce blk_replace_bs Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 05/35] qdev-properties: PropertyInfo: add realized_set_allowed field Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` Vladimir Sementsov-Ogievskiy [this message]
2021-06-10 11:25 ` [PATCH v5 07/35] block: rename backup-top to copy-before-write Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 08/35] block-copy: always set BDRV_REQ_SERIALISING flag Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 09/35] block/block-copy: introduce block_copy_set_copy_opts() Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 10/35] block/backup: set copy_range and compress after filter insertion Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 11/35] block/backup: move cluster size calculation to block-copy Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 12/35] block/copy-before-write: relax permission requirements when no parents Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 13/35] block/copy-before-write: drop extra bdrv_unref on failure path Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 14/35] block/copy-before-write: use file child instead of backing Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 15/35] block/copy-before-write: bdrv_cbw_append(): replace child at last Vladimir Sementsov-Ogievskiy
2021-06-10 11:25 ` [PATCH v5 16/35] block/copy-before-write: introduce cbw_init() Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 17/35] block/copy-before-write: cbw_init(): rename variables Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 18/35] block/copy-before-write: cbw_init(): use file child after attaching Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 19/35] block/copy-before-write: bdrv_cbw_append(): drop unused compress arg Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 20/35] block/copy-before-write: cbw_init(): use options Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 21/35] block/copy-before-write: initialize block-copy bitmap Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 22/35] block/block-copy: make setting progress optional Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 23/35] block/copy-before-write: make public block driver Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 24/35] qapi: publish copy-before-write filter Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 25/35] python/qemu/machine.py: refactor _qemu_args() Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 26/35] python/qemu/machine: QEMUMachine: improve qmp() method Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 27/35] iotests.py: VM: add own __enter__ method Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 28/35] iotests/222: fix pylint and mypy complains Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 29/35] iotests/222: constantly use single quotes for strings Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 30/35] iotests: move 222 to tests/image-fleecing Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 31/35] iotests.py: hmp_qemu_io: support qdev Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 32/35] iotests/image-fleecing: proper source device Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 33/35] iotests/image-fleecing: rename tgt_node Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 34/35] iotests/image-fleecing: prepare for adding new test-case Vladimir Sementsov-Ogievskiy
2021-06-10 11:26 ` [PATCH v5 35/35] iotests/image-fleecing: add test-case for copy-before-write filter Vladimir Sementsov-Ogievskiy
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