Re: [gmediaserver-devel] File size limit

[Mark Broadbent]

Jan Ceuleers wrote:
> Wayne Stallwood wrote:
> > On Tue, 2007-07-03 at 20:20 +0200, Jan Ceuleers wrote:
> >  
> > > However, if I strace the process, the stat64() call actually returns 
> > > zero:
> > >
> > > stat64("/home/storage/Test/Eragon-001.avi", {st_mode=S_IFREG|0644, 
> > > st_size=2200526492, ...}) = 0
> > >     
> >
> > Maybe I am being a bit daft here but isn't stat64 actually returning 
> > an exit status of 0 there and a file size of 2200526492 bytes
> >   
> Absolutely correct. But if you check the source code, you'll see that 
> the piece of code that generates the error message is only executed if 
> the stat() call returns a negative value.
>
> So: the source code contains a stat() call; the library appears to 
> translate that into a stat64() call which returns zero; the library then 
> presumably does some more checking and finds that the file is too large 
> to be supported by the stat() call so it returns a negative value instead.
>
> I have since changed the stat() call into a stat64 call myself (along 
> with the necessary changes in variable declarations). This then causes 
> the subsequent open() call to fail. Unfortunately there does not seem to 
> be a 64-bit equivalent of the open() call, so I'm stuck.
>
> Subsequent to my message I also found out that the block size of the 
> ext3 filesystem might be relevant. The block size is 4K, so I would not 
> expect this to be the reason for the failure.

This is fairly easy to fix (provided that all the correct types have 
been used with the stat, open APIs).

You don't need to explicitly use the stat64 call if you add the 
following to compile line:

gcc -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE

This will automatically switch to using the large file compatible system 
call variants (i.e. stat becomes stat64).  When using open you will also 
need to use the O_LARGEFILE flag as well to successfully open it.

See http://www.suse.de/~aj/linux_lfs.html for more information.

Cheers
Mark