From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Subject: Re: [PATCHv2 1/2] Xen PV backend: Move call to bdrv_new
 from blk_init to blk_connect
Date: Fri, 5 Apr 2013 15:22:16 +0100
Message-ID: <alpine.DEB.2.02.1304051516460.5078__11250.4734112465$1365284580$gmane$org@kaball.uk.xensource.com>
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To: Alex Bligh <alex@alex.org.uk>
Cc: Ian Campbell <Ian.Campbell@citrix.com>, Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>, George Dunlap <George.Dunlap@eu.citrix.com>, Ian Jackson <Ian.Jackson@eu.citrix.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, xen-devel <xen-devel@lists.xen.org>, Anthony Liguori <anthony@codemonkey.ws>, Paolo Bonzini <pbonzini@redhat.com>
List-Id: xen-devel@lists.xenproject.org

On Fri, 5 Apr 2013, Alex Bligh wrote:
> This commit delays the point at which bdrv_new (and hence blk_open
> on the underlying device) is called from blk_init to blk_connect.
> This ensures that in an inbound live migrate, the block device is
> not opened until it has been closed at the other end. This is in
> preparation for supporting devices with open/close consistency
> without using O_DIRECT. This commit does NOT itself change O_DIRECT
> semantics.
> 
> Commit f3903bbac78a81fcbce1350cdce860764a62783a (in xen's qemu-upstream
> repo but not in qemu's repo) should be reverted prior to applying
> this commit.
> 
> Signed-off-by: Alex Bligh <alex@alex.org.uk>
> ---
>  hw/xen_disk.c |   71 ++++++++++++++++++++++++++++++++-------------------------
>  1 file changed, 40 insertions(+), 31 deletions(-)
> 
> diff --git a/hw/xen_disk.c b/hw/xen_disk.c
> index 69e1d9d..dd5a711 100644
> --- a/hw/xen_disk.c
> +++ b/hw/xen_disk.c
> @@ -701,7 +701,7 @@ static void blk_alloc(struct XenDevice *xendev)
>  static int blk_init(struct XenDevice *xendev)
>  {
>      struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
> -    int index, qflags, info = 0;
> +    int info = 0;
>  
>      /* read xenstore entries */
>      if (blkdev->params == NULL) {
> @@ -744,10 +744,7 @@ static int blk_init(struct XenDevice *xendev)
>      }
>  
>      /* read-only ? */
> -    qflags = BDRV_O_NOCACHE | BDRV_O_CACHE_WB | BDRV_O_NATIVE_AIO;
> -    if (strcmp(blkdev->mode, "w") == 0) {
> -        qflags |= BDRV_O_RDWR;
> -    } else {
> +    if (strcmp(blkdev->mode, "w")) {
>          info  |= VDISK_READONLY;
>      }
>  
> @@ -756,6 +753,41 @@ static int blk_init(struct XenDevice *xendev)
>          info  |= VDISK_CDROM;
>      }
>  
> +    blkdev->file_blk  = BLOCK_SIZE;

This is useless, you are setting file_blk twice. Just remove this please.