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[PATCH v8 14/14] block: Convert 'block_resize' to coroutine
From: |
Kevin Wolf |
Subject: |
[PATCH v8 14/14] block: Convert 'block_resize' to coroutine |
Date: |
Mon, 5 Oct 2020 17:58:55 +0200 |
block_resize performs some I/O that could potentially take quite some
time, so use it as an example for the new 'coroutine': true annotation
in the QAPI schema.
bdrv_truncate() requires that we're already in the right AioContext for
the BlockDriverState if called in coroutine context. So instead of just
taking the AioContext lock, move the QMP handler coroutine to the
context.
Call blk_unref() only after switching back because blk_unref() may only
be called in the main thread.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
qapi/block-core.json | 3 ++-
blockdev.c | 16 ++++++++--------
hmp-commands.hx | 1 +
3 files changed, 11 insertions(+), 9 deletions(-)
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 12a24772b5..90383b0148 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1304,7 +1304,8 @@
{ 'command': 'block_resize',
'data': { '*device': 'str',
'*node-name': 'str',
- 'size': 'int' } }
+ 'size': 'int' },
+ 'coroutine': true }
##
# @NewImageMode:
diff --git a/blockdev.c b/blockdev.c
index bebd3ba1c3..e331f81034 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2439,14 +2439,14 @@ BlockDirtyBitmapSha256
*qmp_x_debug_block_dirty_bitmap_sha256(const char *node,
return ret;
}
-void qmp_block_resize(bool has_device, const char *device,
- bool has_node_name, const char *node_name,
- int64_t size, Error **errp)
+void coroutine_fn qmp_block_resize(bool has_device, const char *device,
+ bool has_node_name, const char *node_name,
+ int64_t size, Error **errp)
{
Error *local_err = NULL;
BlockBackend *blk = NULL;
BlockDriverState *bs;
- AioContext *aio_context;
+ AioContext *old_ctx;
bs = bdrv_lookup_bs(has_device ? device : NULL,
has_node_name ? node_name : NULL,
@@ -2456,9 +2456,6 @@ void qmp_block_resize(bool has_device, const char *device,
return;
}
- aio_context = bdrv_get_aio_context(bs);
- aio_context_acquire(aio_context);
-
if (size < 0) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "size", "a >0 size");
goto out;
@@ -2475,12 +2472,15 @@ void qmp_block_resize(bool has_device, const char
*device,
}
bdrv_drained_begin(bs);
+ old_ctx = bdrv_co_enter(bs);
blk_truncate(blk, size, false, PREALLOC_MODE_OFF, 0, errp);
+ bdrv_co_leave(bs, old_ctx);
bdrv_drained_end(bs);
out:
+ bdrv_co_lock(bs);
blk_unref(blk);
- aio_context_release(aio_context);
+ bdrv_co_unlock(bs);
}
void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 1088d64503..de83a5cc61 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -76,6 +76,7 @@ ERST
.params = "device size",
.help = "resize a block image",
.cmd = hmp_block_resize,
+ .coroutine = true,
},
SRST
--
2.25.4
- [PATCH v8 03/14] monitor: Use getter/setter functions for cur_mon, (continued)
- [PATCH v8 03/14] monitor: Use getter/setter functions for cur_mon, Kevin Wolf, 2020/10/05
- [PATCH v8 05/14] qmp: Assert that no other monitor is active, Kevin Wolf, 2020/10/05
- [PATCH v8 06/14] qmp: Call monitor_set_cur() only in qmp_dispatch(), Kevin Wolf, 2020/10/05
- [PATCH v8 07/14] monitor: Make current monitor a per-coroutine property, Kevin Wolf, 2020/10/05
- [PATCH v8 08/14] qapi: Add a 'coroutine' flag for commands, Kevin Wolf, 2020/10/05
- [PATCH v8 09/14] qmp: Move dispatcher to a coroutine, Kevin Wolf, 2020/10/05
- [PATCH v8 12/14] block: Add bdrv_co_enter()/leave(), Kevin Wolf, 2020/10/05
- [PATCH v8 11/14] util/async: Add aio_co_reschedule_self(), Kevin Wolf, 2020/10/05
- [PATCH v8 10/14] hmp: Add support for coroutine command handlers, Kevin Wolf, 2020/10/05
- [PATCH v8 13/14] block: Add bdrv_lock()/unlock(), Kevin Wolf, 2020/10/05
- [PATCH v8 14/14] block: Convert 'block_resize' to coroutine,
Kevin Wolf <=
- Re: [PATCH v8 00/14] monitor: Optionally run handlers in coroutines, Markus Armbruster, 2020/10/06
- Re: [PATCH v8 00/14] monitor: Optionally run handlers in coroutines, Stefan Hajnoczi, 2020/10/08