* [Qemu-devel] [PATCH] blockdev: acquire AioContext in hmp_commit()
@ 2015-10-30 15:57 Stefan Hajnoczi
2015-10-30 16:01 ` [Qemu-devel] [Qemu-block] " Jeff Cody
2015-11-01 17:50 ` [Qemu-devel] " Denis V. Lunev
0 siblings, 2 replies; 4+ messages in thread
From: Stefan Hajnoczi @ 2015-10-30 15:57 UTC (permalink / raw)
To: qemu-devel
Cc: Kevin Wolf, Denis V. Lunev, Stefan Hajnoczi, Markus Armbruster,
qemu-block
This one slipped through. Although we acquire AioContext when
committing all devices we don't for just a single device.
AioContext must be acquired before calling bdrv_*() functions to
synchronize access with other threads that may be using the AioContext.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
blockdev.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/blockdev.c b/blockdev.c
index 18712d2..d611779 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1120,6 +1120,9 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
if (!strcmp(device, "all")) {
ret = bdrv_commit_all();
} else {
+ BlockDriverState *bs;
+ AioContext *aio_context;
+
blk = blk_by_name(device);
if (!blk) {
monitor_printf(mon, "Device '%s' not found\n", device);
@@ -1129,7 +1132,14 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
monitor_printf(mon, "Device '%s' has no medium\n", device);
return;
}
- ret = bdrv_commit(blk_bs(blk));
+
+ bs = blk_bs(blk);
+ aio_context = bdrv_get_aio_context(bs);
+ aio_context_acquire(aio_context);
+
+ ret = bdrv_commit(bs);
+
+ aio_context_release(aio_context);
}
if (ret < 0) {
monitor_printf(mon, "'commit' error for '%s': %s\n", device,
--
2.4.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [Qemu-block] [PATCH] blockdev: acquire AioContext in hmp_commit()
2015-10-30 15:57 [Qemu-devel] [PATCH] blockdev: acquire AioContext in hmp_commit() Stefan Hajnoczi
@ 2015-10-30 16:01 ` Jeff Cody
2015-11-01 17:50 ` [Qemu-devel] " Denis V. Lunev
1 sibling, 0 replies; 4+ messages in thread
From: Jeff Cody @ 2015-10-30 16:01 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: Kevin Wolf, Denis V. Lunev, qemu-devel, qemu-block, Markus Armbruster
On Fri, Oct 30, 2015 at 03:57:41PM +0000, Stefan Hajnoczi wrote:
> This one slipped through. Although we acquire AioContext when
> committing all devices we don't for just a single device.
>
> AioContext must be acquired before calling bdrv_*() functions to
> synchronize access with other threads that may be using the AioContext.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
> blockdev.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/blockdev.c b/blockdev.c
> index 18712d2..d611779 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -1120,6 +1120,9 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
> if (!strcmp(device, "all")) {
> ret = bdrv_commit_all();
> } else {
> + BlockDriverState *bs;
> + AioContext *aio_context;
> +
> blk = blk_by_name(device);
> if (!blk) {
> monitor_printf(mon, "Device '%s' not found\n", device);
> @@ -1129,7 +1132,14 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
> monitor_printf(mon, "Device '%s' has no medium\n", device);
> return;
> }
> - ret = bdrv_commit(blk_bs(blk));
> +
> + bs = blk_bs(blk);
> + aio_context = bdrv_get_aio_context(bs);
> + aio_context_acquire(aio_context);
> +
> + ret = bdrv_commit(bs);
> +
> + aio_context_release(aio_context);
> }
> if (ret < 0) {
> monitor_printf(mon, "'commit' error for '%s': %s\n", device,
> --
> 2.4.3
>
>
Reviewed-by: Jeff Cody <jcody@redhat.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH] blockdev: acquire AioContext in hmp_commit()
2015-10-30 15:57 [Qemu-devel] [PATCH] blockdev: acquire AioContext in hmp_commit() Stefan Hajnoczi
2015-10-30 16:01 ` [Qemu-devel] [Qemu-block] " Jeff Cody
@ 2015-11-01 17:50 ` Denis V. Lunev
2015-11-02 13:29 ` Stefan Hajnoczi
1 sibling, 1 reply; 4+ messages in thread
From: Denis V. Lunev @ 2015-11-01 17:50 UTC (permalink / raw)
To: Stefan Hajnoczi, qemu-devel; +Cc: Kevin Wolf, Markus Armbruster, qemu-block
On 10/30/2015 06:57 PM, Stefan Hajnoczi wrote:
> This one slipped through. Although we acquire AioContext when
> committing all devices we don't for just a single device.
>
> AioContext must be acquired before calling bdrv_*() functions to
> synchronize access with other threads that may be using the AioContext.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
> blockdev.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/blockdev.c b/blockdev.c
> index 18712d2..d611779 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -1120,6 +1120,9 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
> if (!strcmp(device, "all")) {
> ret = bdrv_commit_all();
> } else {
> + BlockDriverState *bs;
> + AioContext *aio_context;
> +
> blk = blk_by_name(device);
> if (!blk) {
> monitor_printf(mon, "Device '%s' not found\n", device);
> @@ -1129,7 +1132,14 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
> monitor_printf(mon, "Device '%s' has no medium\n", device);
> return;
> }
> - ret = bdrv_commit(blk_bs(blk));
> +
> + bs = blk_bs(blk);
> + aio_context = bdrv_get_aio_context(bs);
> + aio_context_acquire(aio_context);
> +
> + ret = bdrv_commit(bs);
> +
> + aio_context_release(aio_context);
> }
> if (ret < 0) {
> monitor_printf(mon, "'commit' error for '%s': %s\n", device,
I like it in general, but could you pls wait a bit before pushing
it up. I am working at the moment on a more generic series.
I am going to attach this patch to it to consider the situation
as a whole.
It would be much trickier than my previous one. There are
several other places discovered.
Den
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH] blockdev: acquire AioContext in hmp_commit()
2015-11-01 17:50 ` [Qemu-devel] " Denis V. Lunev
@ 2015-11-02 13:29 ` Stefan Hajnoczi
0 siblings, 0 replies; 4+ messages in thread
From: Stefan Hajnoczi @ 2015-11-02 13:29 UTC (permalink / raw)
To: Denis V. Lunev
Cc: Kevin Wolf, qemu-block, qemu-devel, Stefan Hajnoczi, Markus Armbruster
[-- Attachment #1: Type: text/plain, Size: 2160 bytes --]
On Sun, Nov 01, 2015 at 08:50:36PM +0300, Denis V. Lunev wrote:
> On 10/30/2015 06:57 PM, Stefan Hajnoczi wrote:
> >This one slipped through. Although we acquire AioContext when
> >committing all devices we don't for just a single device.
> >
> >AioContext must be acquired before calling bdrv_*() functions to
> >synchronize access with other threads that may be using the AioContext.
> >
> >Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> >---
> > blockdev.c | 12 +++++++++++-
> > 1 file changed, 11 insertions(+), 1 deletion(-)
> >
> >diff --git a/blockdev.c b/blockdev.c
> >index 18712d2..d611779 100644
> >--- a/blockdev.c
> >+++ b/blockdev.c
> >@@ -1120,6 +1120,9 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
> > if (!strcmp(device, "all")) {
> > ret = bdrv_commit_all();
> > } else {
> >+ BlockDriverState *bs;
> >+ AioContext *aio_context;
> >+
> > blk = blk_by_name(device);
> > if (!blk) {
> > monitor_printf(mon, "Device '%s' not found\n", device);
> >@@ -1129,7 +1132,14 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
> > monitor_printf(mon, "Device '%s' has no medium\n", device);
> > return;
> > }
> >- ret = bdrv_commit(blk_bs(blk));
> >+
> >+ bs = blk_bs(blk);
> >+ aio_context = bdrv_get_aio_context(bs);
> >+ aio_context_acquire(aio_context);
> >+
> >+ ret = bdrv_commit(bs);
> >+
> >+ aio_context_release(aio_context);
> > }
> > if (ret < 0) {
> > monitor_printf(mon, "'commit' error for '%s': %s\n", device,
> I like it in general, but could you pls wait a bit before pushing
> it up. I am working at the moment on a more generic series.
> I am going to attach this patch to it to consider the situation
> as a whole.
>
> It would be much trickier than my previous one. There are
> several other places discovered.
Sure. We need to solve the missing AioContext acquires by hard freeze
(2015-11-12, see http://qemu-project.org/Planning/2.5). Until then we
can discuss different solutions.
Stefan
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2015-10-30 15:57 [Qemu-devel] [PATCH] blockdev: acquire AioContext in hmp_commit() Stefan Hajnoczi
2015-10-30 16:01 ` [Qemu-devel] [Qemu-block] " Jeff Cody
2015-11-01 17:50 ` [Qemu-devel] " Denis V. Lunev
2015-11-02 13:29 ` Stefan Hajnoczi
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