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Subject: [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use
 bdrv_(p)write_sync for metadata writes"
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Kevin Wolf <kwolf@redhat.com>, stefanha@gmail.com, mjt@tls.msk.ru, qemu-devel@nongnu.org, hch@lst.de

  On 08/24/2010 04:40 PM, Anthony Liguori wrote:
>> 1. Allocate a cluster (increase refcount table)
>>
>> 2. Link cluster to L2 table
>>
>> 3. Second operation makes it to disk; first still in pagecache
>>
>> 4. Crash
>>
>> 5. Dangling pointer from L2 to freed cluster
>
>
> Yes, having this discussion in IRC.
>
> The problem is that we maintain a refcount table. 

Are you sure that's the only issue?

> If we didn't do internal disk snapshots, we wouldn't have this 
> problem.  IOW, VMDK doesn't have this problem so the answer to my very 
> first question is that qcow2 is too difficult a format to get right.

One doesn't follow from the other (though I'm no fan of internal 
snapshots, myself).

-- 
error compiling committee.c: too many arguments to function