Re: [PATCH] Journal support for ext2

[Robert Millan]

On Thu, Mar 20, 2008 at 02:03:45PM +0800, Bean wrote:
> On Thu, Mar 20, 2008 at 8:12 AM, Robert Millan <address@hidden> wrote:
> >
> >  Hi!
> >
> >  Is this patch supposed to fix > 32-bit disk addressing in filesystems?  I
> >  just setup a ~4 TB hard disk for testing (in qemu), and added a (gpt) 
> > partition
> >  at the end of it, surely above the 2 TiB barrier.
> >
> >  What I found puzzling is that grub-emu is capable of listing files in that
> >  partition _without_ this patch.  Any idea why?  This wasn't really supposed
> >  to work was it?
> >
> >  Note: grub itself can't read it yet, but this must be due to disk io 
> > problems
> >  (asides from the lba32 limit in bochsbios).
> 
> Hi,
> 
> the sector parameter in grub_disk_read is 64-bit, so it can read from
> disk larger than 4g.The fs interface is using 64-bit address as well,
> so if the implementation is all right, it can handle large partition.

Ah, that explains it.  Note that the disk io part can't handle it yet,
though.  I'll have a look into that (bochsbios itself limits it, but ata.mod
didn't work either).

> The problem is that fshelp function use int for offset and block
> number, which limit the maximum file size to 4g. You can verify this
> with loopback on a large file.

Ah ok.

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call… if you are unable to speak?
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