Date:	Wed, 23 Nov 2011 19:34:10 +0900
From:	NamJae Jeon <linkinjeon@...il.com>
To:	stern@...land.harvard.edu
Cc:	Jeff Layton <jlayton@...hat.com>, Steve French <sfrench@...ba.org>,
	linux-cifs@...r.kernel.org, samba-technical@...ts.samba.org,
	LKML <linux-kernel@...r.kernel.org>,
	Unix Support <unix-support@....cam.ac.uk>,
	Steve French <smfrench@...il.com>, akpm@...ux-foundation.org,
	Anton Altaparmakov <aia21@....ac.uk>, ashishsangwan2@...il.com
Subject: Re: CIFS: Rename bug on servers not supporting inode numbers

Hi. Alan.
Would you know why there is no upper/lower case table in nls utf8 ?
And Currently Surrogate pair is not supported also in nls utf8. Is
there the reason ?

2011/11/4 NamJae Jeon <linkinjeon@...il.com>:
> 2011/11/4 Steve French <smfrench@...il.com>:
>> What is the actual sequence of events from the wire perspective (the
>> actual smb requests sent)?
>>
>>
>> On Thu, Nov 3, 2011 at 6:25 PM, Anton Altaparmakov <aia21@....ac.uk> wrote:
>>> Hi,
>>>
>>> On 3 Nov 2011, at 17:40, Jeff Layton wrote:
>>>> On Thu, 3 Nov 2011 15:42:13 +0000 Anton Altaparmakov <aia21@....ac.uk> wrote:
>>>>>
>>>>> I should add that we are using iocharset=utf8 mount option which means that the dcache hash/compare functions done in the cifs module do not work because it uses nls_tolower() and nls_strnicmp() both of which for utf8 NLS in the kernel do not do anything at all and effectively behave case sensitively!
>>>>>
>>>>> Thus this bug/problem in all likelyhood only affects utf8 iocharset users on a case-insensitive but case-preserving CIFS server that does not support server inode numbers.
>
> Hi.
> There is no upper/lower case table on nls utf8. so If you use iocharset=utf8,
> filesystem will be case sensitive.
> so we can add upper/lower case table like other charset.
> And Currently surrogate pair is not working on nls utf8.
> because it is limited by MAX_WCHAR_T in nls utf8
> I think that upper/lower case table and surrogate pair support should
> be fixed on nls utf8.
> I should know Andrew's opinion to fix these problem.
>>>>>
>>>>> That probably explains why it has not been noticed before!
>>>>>
>>>>> We need utf8 thus we still need to fix this issue.
>>>
>>>> I'm confused...
>>>>
>>>> If the filesystem being served out by the server is using utf8, then
>>>> how is it handling the case-insensitivity?
>>>
>>>
>>> The file system being served is NSS (the Netware one but now mounted on Open Enterprise Server with Linux kernel rather than actual Netware kernel).  No idea how it works I am afraid.  It supports lots of different namespaces as well as being case-insensitive and case preserving when using the LONG name space (which is now being served through CIFS).
>>>
>>> If it was NTFS or exFAT I could tell you exactly how they work (each volume has an upcase table mapping the 65536 UCS-2 Unicode characters to their upper case equivalents and each 16-bit character is upper-cased individually, more recently Windows has switched to using UTF-16 instead of UCS-2 and the upcase table changed when that happened though it remained the same size and I think for file system purposes the fact that there are surrogates in the above UCS-2   Unicode range is simply ignored)...
>>>
>>> Best regards,
>>>
>>>        Anton
>>> --
>>> Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
>>> Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
>>> Linux NTFS maintainer, http://www.linux-ntfs.org/
>>>
>>>
>>
>>
>>
>> --
>> Thanks,
>>
>> Steve
>> --
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