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Re: [Qemu-devel] [Xen-devel] [PATCH] xen_disk: implement BLKIF_OP_FLUSH_
From: |
Ian Campbell |
Subject: |
Re: [Qemu-devel] [Xen-devel] [PATCH] xen_disk: implement BLKIF_OP_FLUSH_DISKCACHE, remove BLKIF_OP_WRITE_BARRIER |
Date: |
Wed, 25 Apr 2012 10:02:45 +0100 |
On Wed, 2012-04-25 at 09:45 +0100, Christoph Hellwig wrote:
> > - case BLKIF_OP_WRITE_BARRIER:
> > + case BLKIF_OP_FLUSH_DISKCACHE:
> > if (!ioreq->req.nr_segments) {
> > ioreq->presync = 1;
> > return 0;
> > }
> > - ioreq->presync = ioreq->postsync = 1;
> > + ioreq->postsync = 1;
> > /* fall through */
>
> It might be worth documenting the semantics of BLKIF_OP_FLUSH_DISKCACHE
> in a comment here. I haven't found any spec for the xen_disk protocol,
The blkif spec was recently much improved, you can find it at
http://xenbits.xen.org/docs/unstable/hypercall/include,public,io,blkif.h.html
TBH I'm not sure it actually answers your questions wrt
BLKIF_OP_FLUSH_DISKCACHE, if not please let us know and we can see about
improving it.
Ian
- [Qemu-devel] [PATCH] xen_disk: implement BLKIF_OP_FLUSH_DISKCACHE, remove BLKIF_OP_WRITE_BARRIER, Stefano Stabellini, 2012/04/16
- Re: [Qemu-devel] [PATCH] xen_disk: implement BLKIF_OP_FLUSH_DISKCACHE, remove BLKIF_OP_WRITE_BARRIER, Konrad Rzeszutek Wilk, 2012/04/16
- Re: [Qemu-devel] [PATCH] xen_disk: implement BLKIF_OP_FLUSH_DISKCACHE, remove BLKIF_OP_WRITE_BARRIER, Christoph Hellwig, 2012/04/25
- Re: [Qemu-devel] [Xen-devel] [PATCH] xen_disk: implement BLKIF_OP_FLUSH_DISKCACHE, remove BLKIF_OP_WRITE_BARRIER,
Ian Campbell <=
- Re: [Qemu-devel] [Xen-devel] [PATCH] xen_disk: implement BLKIF_OP_FLUSH_DISKCACHE, remove BLKIF_OP_WRITE_BARRIER, Christoph Hellwig, 2012/04/25
- Re: [Qemu-devel] [Xen-devel] [PATCH] xen_disk: implement BLKIF_OP_FLUSH_DISKCACHE, remove BLKIF_OP_WRITE_BARRIER, Stefano Stabellini, 2012/04/25
- Re: [Qemu-devel] [Xen-devel] [PATCH] xen_disk: implement BLKIF_OP_FLUSH_DISKCACHE, remove BLKIF_OP_WRITE_BARRIER, Ian Campbell, 2012/04/25
- Re: [Qemu-devel] [Xen-devel] [PATCH] xen_disk: implement BLKIF_OP_FLUSH_DISKCACHE, remove BLKIF_OP_WRITE_BARRIER, Christoph Hellwig, 2012/04/25
- Re: [Qemu-devel] [Xen-devel] [PATCH] xen_disk: implement BLKIF_OP_FLUSH_DISKCACHE, remove BLKIF_OP_WRITE_BARRIER, Konrad Rzeszutek Wilk, 2012/04/26