Re: [Qemu-devel] [PATCH for-2.6 v2] block: Don't ignore flags in blk_{, co, aio}_write_zeroes()

[Eric Blake <eblake@redhat.com>]

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On 04/15/2016 08:52 AM, Kevin Wolf wrote:
> Commit 57d6a428 neglected to pass the given flags to blk_aio_prwv(),
> which broke discard by WRITE SAME for scsi-disk (the UNMAP bit would be
> ignored).
> 
> Commit fc1453cd introduced the same bug for blk_write_zeroes(). This is
> used for 'qemu-img convert' without has_zero_init (e.g. on a block
> device) and for preallocation=falloc in parallels.
> 
> Commit 8896e088 is the version for blk_co_write_zeroes(). This function
> is only used in qemu-io.
> 
> Reported-by: Max Reitz <mreitz@redhat.com>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
> 
> v2:
> - There are two more places with exactly the same bug [Eric]

Not just me; Pavel spotted it first:
https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg01613.html

> 
>  block/block-backend.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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