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From(H. Peter Anvin)
SubjectRe: 2G file size limitation question
Date7 Jan 1998 09:35:34 GMT
Followup to:  <Pine.LNX.3.95.980106163335.24738A-100000@gumby.dynatec.com>
By author:    Matt Nelson <mnelson@dynatec.com>
In newsgroup: linux.dev.kernel
> as far as i can tell, the ext2 filesystem code limits files to a maximum
> of 2G (although i haven't yet found _exactly_ where this limit is set...).
> 

The size field in the inode.  It is also a limitation of the VFS
layer, and libc (struct stat, for one.)

> we have a need to use files larger than 2G (ugh, dont ask - we also need
> to bump our machine up from 512M to 1G or more of memory...), so i have a
> couple of questions:
> 
>  - why is there a 2G limit?

Because that's where a signed 32-bit integer runs out.

>  - can the 2G limit be _safely_ increased (to, say, about 5G)?
>  - if so, what changes are needed in the ext2 code to do it?

Massive changes, including a format change in the ext2 filesystem
(which should be backward-compatible if done right, though.)

> the machine in question is running a pre-something version of 2.0.31.  i
> wouldn't mind moving to a newer 2.0.x kernel, if need be.

Large files *might* be introduced in the 2.3.x kernels, but no sooner
than that.

	-hpa
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