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[PULL v3 22/28] block/export: add iothread and fixed-iothread options
From: |
Stefan Hajnoczi |
Subject: |
[PULL v3 22/28] block/export: add iothread and fixed-iothread options |
Date: |
Fri, 23 Oct 2020 16:21:41 +0100 |
Make it possible to specify the iothread where the export will run. By
default the block node can be moved to other AioContexts later and the
export will follow. The fixed-iothread option forces strict behavior
that prevents changing AioContext while the export is active. See the
QAPI docs for details.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200929125516.186715-5-stefanha@redhat.com
[Fix stray '#' character in block-export.json and add missing "(since:
5.2)" as suggested by Eric Blake.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
qapi/block-export.json | 11 ++++++++++
block/export/export.c | 31 +++++++++++++++++++++++++++-
block/export/vhost-user-blk-server.c | 5 ++++-
nbd/server.c | 2 --
4 files changed, 45 insertions(+), 4 deletions(-)
diff --git a/qapi/block-export.json b/qapi/block-export.json
index a793e34af9..8a4ced817f 100644
--- a/qapi/block-export.json
+++ b/qapi/block-export.json
@@ -219,11 +219,22 @@
# export before completion is signalled. (since: 5.2;
# default: false)
#
+# @iothread: The name of the iothread object where the export will run. The
+# default is to use the thread currently associated with the
+# block node. (since: 5.2)
+#
+# @fixed-iothread: True prevents the block node from being moved to another
+# thread while the export is active. If true and @iothread is
+# given, export creation fails if the block node cannot be
+# moved to the iothread. The default is false. (since: 5.2)
+#
# Since: 4.2
##
{ 'union': 'BlockExportOptions',
'base': { 'type': 'BlockExportType',
'id': 'str',
+ '*fixed-iothread': 'bool',
+ '*iothread': 'str',
'node-name': 'str',
'*writable': 'bool',
'*writethrough': 'bool' },
diff --git a/block/export/export.c b/block/export/export.c
index a24fadcfb5..c3478c6c97 100644
--- a/block/export/export.c
+++ b/block/export/export.c
@@ -15,6 +15,7 @@
#include "block/block.h"
#include "sysemu/block-backend.h"
+#include "sysemu/iothread.h"
#include "block/export.h"
#include "block/nbd.h"
#include "qapi/error.h"
@@ -63,10 +64,11 @@ static const BlockExportDriver
*blk_exp_find_driver(BlockExportType type)
BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp)
{
+ bool fixed_iothread = export->has_fixed_iothread && export->fixed_iothread;
const BlockExportDriver *drv;
BlockExport *exp = NULL;
BlockDriverState *bs;
- BlockBackend *blk;
+ BlockBackend *blk = NULL;
AioContext *ctx;
uint64_t perm;
int ret;
@@ -102,6 +104,28 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error
**errp)
ctx = bdrv_get_aio_context(bs);
aio_context_acquire(ctx);
+ if (export->has_iothread) {
+ IOThread *iothread;
+ AioContext *new_ctx;
+
+ iothread = iothread_by_id(export->iothread);
+ if (!iothread) {
+ error_setg(errp, "iothread \"%s\" not found", export->iothread);
+ goto fail;
+ }
+
+ new_ctx = iothread_get_aio_context(iothread);
+
+ ret = bdrv_try_set_aio_context(bs, new_ctx, errp);
+ if (ret == 0) {
+ aio_context_release(ctx);
+ aio_context_acquire(new_ctx);
+ ctx = new_ctx;
+ } else if (fixed_iothread) {
+ goto fail;
+ }
+ }
+
/*
* Block exports are used for non-shared storage migration. Make sure
* that BDRV_O_INACTIVE is cleared and the image is ready for write
@@ -116,6 +140,11 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error
**errp)
}
blk = blk_new(ctx, perm, BLK_PERM_ALL);
+
+ if (!fixed_iothread) {
+ blk_set_allow_aio_context_change(blk, true);
+ }
+
ret = blk_insert_bs(blk, bs, errp);
if (ret < 0) {
goto fail;
diff --git a/block/export/vhost-user-blk-server.c
b/block/export/vhost-user-blk-server.c
index f7021cbd7b..286eb5fb9a 100644
--- a/block/export/vhost-user-blk-server.c
+++ b/block/export/vhost-user-blk-server.c
@@ -323,13 +323,17 @@ static const VuDevIface vu_blk_iface = {
static void blk_aio_attached(AioContext *ctx, void *opaque)
{
VuBlkExport *vexp = opaque;
+
+ vexp->export.ctx = ctx;
vhost_user_server_attach_aio_context(&vexp->vu_server, ctx);
}
static void blk_aio_detach(void *opaque)
{
VuBlkExport *vexp = opaque;
+
vhost_user_server_detach_aio_context(&vexp->vu_server);
+ vexp->export.ctx = NULL;
}
static void
@@ -384,7 +388,6 @@ static int vu_blk_exp_create(BlockExport *exp,
BlockExportOptions *opts,
vu_blk_initialize_config(blk_bs(exp->blk), &vexp->blkcfg,
logical_block_size);
- blk_set_allow_aio_context_change(exp->blk, true);
blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
vexp);
diff --git a/nbd/server.c b/nbd/server.c
index e75c825879..08b621f70a 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1517,8 +1517,6 @@ static int nbd_export_create(BlockExport *blk_exp,
BlockExportOptions *exp_args,
return ret;
}
- blk_set_allow_aio_context_change(blk, true);
-
QTAILQ_INIT(&exp->clients);
exp->name = g_strdup(arg->name);
exp->description = g_strdup(arg->description);
--
2.26.2
- [PULL v3 25/28] block/io: bdrv_common_block_status_above: support include_base, (continued)
- [PULL v3 25/28] block/io: bdrv_common_block_status_above: support include_base, Stefan Hajnoczi, 2020/10/23
- [PULL v3 23/28] block/export: add vhost-user-blk multi-queue support, Stefan Hajnoczi, 2020/10/23
- [PULL v3 24/28] block/io: fix bdrv_co_block_status_above, Stefan Hajnoczi, 2020/10/23
- [PULL v3 19/28] util/vhost-user-server: use static library in meson.build, Stefan Hajnoczi, 2020/10/23
- [PULL v3 18/28] util/vhost-user-server: move header to include/, Stefan Hajnoczi, 2020/10/23
- [PULL v3 26/28] block/io: bdrv_common_block_status_above: support bs == base, Stefan Hajnoczi, 2020/10/23
- [PULL v3 20/28] qemu-storage-daemon: avoid compiling blockdev_ss twice, Stefan Hajnoczi, 2020/10/23
- [PULL v3 17/28] block/export: convert vhost-user-blk server to block export API, Stefan Hajnoczi, 2020/10/23
- [PULL v3 27/28] block/io: fix bdrv_is_allocated_above, Stefan Hajnoczi, 2020/10/23
- [PULL v3 28/28] iotests: add commit top->base cases to 274, Stefan Hajnoczi, 2020/10/23
- [PULL v3 22/28] block/export: add iothread and fixed-iothread options,
Stefan Hajnoczi <=
- Re: [PULL v3 00/28] Block patches, no-reply, 2020/10/23
- Re: [PULL v3 00/28] Block patches, Peter Maydell, 2020/10/26