Re: [Qemu-devel] [RFC V6 07/11] quorum: Add quorum mechanism.

[Eric Blake <eblake@redhat.com>]

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On 01/17/2013 08:51 AM, Benoît Canet wrote:
> Signed-off-by: Benoit Canet <benoit@irqsave.net>
> ---
>  block/quorum.c |  278 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 277 insertions(+), 1 deletion(-)
> 
> diff --git a/block/quorum.c b/block/quorum.c
> index 98052eb..2bffff4 100644
> --- a/block/quorum.c
> +++ b/block/quorum.c
> @@ -14,6 +14,20 @@
>   */
>  
>  #include "block/block_int.h"
> +#include "zlib.h"

Since zlib.h isn't part of qemu.git, this should be <zlib.h>.

> +
> +static unsigned long quorum_compute_checksum(QuorumAIOCB *acb, int i)
> +{
> +    int j;
> +    unsigned long adler = adler32(0L, Z_NULL, 0);

Hmm, adler32() is basically a weak hashing mechanism; are you sure you
won't have any false collisions?  Furthermore, how does this compare
with the series for adding deduplication, which uses much
stronger/longer hashes, but where those take more time to compute?  Is
there any way you can share efforts between the two series?

> +    /* get the index of the first successfull read */

s/successfull/successful/ (several times in this patch)

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


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