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Re: inode64 and 64bit kernel with 32bit userspace

To: Matthias Schniedermeyer <ms@xxxxxxx>
Subject: Re: inode64 and 64bit kernel with 32bit userspace
From: Eric Sandeen <sandeen@xxxxxxxxxxx>
Date: Mon, 18 Feb 2013 10:39:17 -0600
Cc: xfs@xxxxxxxxxxx
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <20130218162032.GA16259@xxxxxxx>
References: <20130218094320.GA24644@xxxxxxx> <512244CE.5030008@xxxxxxxxxxx> <20130218162032.GA16259@xxxxxxx>
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:17.0) Gecko/20130107 Thunderbird/17.0.2
On 2/18/13 10:20 AM, Matthias Schniedermeyer wrote:
> On 18.02.2013 09:12, Eric Sandeen wrote:
>> On 2/18/13 3:43 AM, Matthias Schniedermeyer wrote:
>>> Hi
>>>
>>>
>>> The more or less simple question is:
>>> Is the requirement for 32bit programs to support 64bit inodes the same 
>>> as LFS(Large File Support)?
>>>
>>> IOW if a programs was compiled with FILE_OFFSET_BITS=64 (if i remember 
>>> that name correctly) should it work?
>>
>> I think so (I don't know where the formal documentation is, 
>> http://users.suse.com/~aj/linux_lfs.html is an old but still good
>> over view I think).  From open(2):
>>
>>        EOVERFLOW
>>               (stat())  path refers to a file whose size cannot be 
>> represented
>>               in the type       off_t.  This can  occur  when  an  
>> application
>>               compiled  on  a  32-bit  platform without 
>> -D_FILE_OFFSET_BITS=64
>>               calls stat() on a file whose size exceeds (2<<31)-1 bits.
>>
>> EOVERFLOW can happen if the inode nubmer doesn't fit in a (32-bit)
>> stat struct as well.
> 
> I've looked into /usr/include/sys/stat.h
> 
> And i see this:
> # ifndef __ino_t_defined
> #  ifndef __USE_FILE_OFFSET64
> typedef __ino_t ino_t;
> #  else
> typedef __ino64_t ino_t;
> #  endif
> #  define __ino_t_defined
> # endif
> 
> So ino_t really is __ino64_t when compiled with the LFS option, which 
> answers my original question. :-)
> 
> Besides i don't have that many programs that (should) care about inodes. 
> Of the top of my head i care about rsync/perl/find/ln/ls, which 
> apparently work correctly.

find cares, ls cares . . . but I would assume that they get it right :)

I'm getting a box set up w/ 32-bit F18, I want to re-run my test over it
and see if things have improved at all in 5 years.  :)

-Eric

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