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[Qemu-devel] [PATCH 3/3] blockdev: acquire AioContext in block_set_io_th
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH 3/3] blockdev: acquire AioContext in block_set_io_throttle |
Date: |
Wed, 14 May 2014 16:22:47 +0200 |
The block_set_io_throttle QMP and HMP commands modify I/O throttling
limits for block devices.
Acquire the BlockDriverState's AioContext to protect against race
conditions with an IOThread that is running I/O for this device.
Cc: Benoît Canet <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
blockdev.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/blockdev.c b/blockdev.c
index 7810e9f..e0f1978 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1663,6 +1663,7 @@ void qmp_block_set_io_throttle(const char *device,
int64_t bps, int64_t bps_rd,
{
ThrottleConfig cfg;
BlockDriverState *bs;
+ AioContext *aio_context;
bs = bdrv_find(device);
if (!bs) {
@@ -1706,6 +1707,9 @@ void qmp_block_set_io_throttle(const char *device,
int64_t bps, int64_t bps_rd,
return;
}
+ aio_context = bdrv_get_aio_context(bs);
+ aio_context_acquire(aio_context);
+
if (!bs->io_limits_enabled && throttle_enabled(&cfg)) {
bdrv_io_limits_enable(bs);
} else if (bs->io_limits_enabled && !throttle_enabled(&cfg)) {
@@ -1715,6 +1719,8 @@ void qmp_block_set_io_throttle(const char *device,
int64_t bps, int64_t bps_rd,
if (bs->io_limits_enabled) {
bdrv_set_io_limits(bs, &cfg);
}
+
+ aio_context_release(aio_context);
}
int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
--
1.9.0