Windows: hardlink support is broken on shared drives

[Adrian Buehlmann]

On 24.08.2010 00:35, Patrick Mézard wrote:
> Le 23/08/10 22:22, Gavin Erry a écrit :
>> All
>>
>>  
>>
>> I’ve been reading this thread with interest since I posted the problem on the discussion list.  Thanks for the fix – I will test it in the next build of Hg.  It seemed strange that GetFileInformationByHandle doesn’t work too well so I had a look (in C++ though)
>>
>>  
>>
>> It seems that you can get different results depending on how the handle was created with the CreateFile function.
>>
>> If I use GENERIC_READ or FILE_GENERIC_READ for the desired access in CreateFile then I get an incorrect hardlink count.
>>
>> Using FILE_READ_ATTRIBUTES | SYNCHRONIZE (which is a subset of FILE_GENERIC_READ) then I get the correct hardlink count over the network.
> 
> OK, I have seen correct links count returned with FILE_READ_ATTRIBUTES. Do you need the SYNCHRONIZE flag too? I am asking because I first tried without it and it failed then with it alone and it succeeds and now without it, it succeeds again. It's late and I will retry again tomorrow. But I cannot make sense of SYNCHRONIZE in this context.
> 
> These flags are really promising, I managed to get the correct link count with all my setups, except when reading through Parallels share, in which case the serial number was zero.
> 
> Thanks for this excellent insight.

Bad news.

$ python testlink.py linka
links=1                             <--- should be 2
serial=-1898895920

For 

  Windows 7 x64 (as client) -> Windows 7 x64 (as server)

With

             fh = win32file.CreateFile(pathname,
                                       0x0080 | 0x00100000L,
                                       win32file.FILE_SHARE_READ,
                                       None, win32file.OPEN_EXISTING, 0, None)

and with

             fh = win32file.CreateFile(pathname,
                                       0,
                                       win32file.FILE_SHARE_READ,
                                       None, win32file.OPEN_EXISTING, 0, None)