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Re: [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request
From: |
Jamie Lokier |
Subject: |
Re: [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request |
Date: |
Fri, 28 Mar 2008 15:07:03 +0000 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
Marcelo Tosatti wrote:
> Its necessary to guarantee that pending AIO writes have reached stable
> storage when the flush request returns.
>
> Also change fsync() to fdatasync(), since the modification time is not
> critical data.
> + if (aio_fsync(O_DSYNC, &acb->aiocb) < 0) {
> BDRVRawState *s = bs->opaque;
> - fsync(s->fd);
> + raw_aio_flush(bs);
> + fdatasync(s->fd);
> +
> + /* We rely on the fact that no other AIO will be submitted
> + * in parallel, but this should be fixed by per-device
> + * AIO queues when allowing multiple CPU's to process IO
> + * in QEMU.
> + */
> + qemu_aio_flush();
I'm a bit confused by this. Why do you need aio_fsync(O_DSYNC) _and_
synchronous fdatasync() calls? Aren't they equivalent?
-- Jamie
- [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request, Marcelo Tosatti, 2008/03/28
- Re: [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request,
Jamie Lokier <=
- Re: [kvm-devel] [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request, Marcelo Tosatti, 2008/03/28
- Re: [kvm-devel] [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request, Paul Brook, 2008/03/28
- Re: [kvm-devel] [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request, Marcelo Tosatti, 2008/03/28
- Re: [kvm-devel] [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request, Paul Brook, 2008/03/28
- Re: [kvm-devel] [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request, Marcelo Tosatti, 2008/03/28
- Re: [kvm-devel] [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request, Jamie Lokier, 2008/03/28
- Re: [kvm-devel] [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request, Paul Brook, 2008/03/28
- Re: [kvm-devel] [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request, Jamie Lokier, 2008/03/28
- Re: [kvm-devel] [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request, Paul Brook, 2008/03/28
- Re: [kvm-devel] [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request, Jamie Lokier, 2008/03/28