Re: [PATCH] blktap2: Invalid logic detecting unaligned buffers in vhd_write_block

[Ross Philipson <ross.philipson@gmail.com>]

On 04/06/2016 10:39 AM, Ian Jackson wrote:
> Ross Philipson writes ("[Xen-devel] [PATCH] blktap2: Invalid logic detecting unaligned buffers in vhd_write_block"):
>> It seems the logic is meant to detect sector unaligned buffers for block
>> writes. The NOTing of the logic instead masks off any unaligned bits and
>> also would cause the function to always fail. It seems the function is not
>> used in any of the tools so that is probably why the problem is not seen.
>> In the vhd_read_block function it is correct.
>>
>> Signed-off-by: Ross Philipson <ross.philipson@ainfosec.com>
>> ---
>> diff --git a/tools/blktap2/vhd/lib/libvhd.c b/tools/blktap2/vhd/lib/libvhd.c
>> index 1fd5b4e..4ebe012 100644
>> --- a/tools/blktap2/vhd/lib/libvhd.c
>> +++ b/tools/blktap2/vhd/lib/libvhd.c
>> @@ -2188,7 +2188,7 @@ vhd_write_block(vhd_context_t *ctx, uint32_t block, char *data)
>>         if (block >= ctx->bat.entries)
>>                 return -ERANGE;
>>
>> -       if ((unsigned long)data & ~(VHD_SECTOR_SIZE -1))
>> +       if ((unsigned long)data & (VHD_SECTOR_SIZE -1))
> 
> Notwithstanding the discussion in the rest of the thread, this is a
> clearly-correct bugfix to the code in tree, so I have queued it.
> 
> However, I had to do so rather manually because something had mangled
> the whitespace.  Ross, can you check your patch submission path,
> please ?
> 
> Ian.
> 

Never mind, I found the problem. Tabs got turned into spaces. Sorry about that.

-- 
Ross Philipson

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