Subject: Re: problem with tmpfs and linux emulation?
To: None <>
From: Matt Thomas <>
List: current-users
Date: 11/09/2005 09:04:36
Thor Lancelot Simon wrote:
> On Wed, Nov 09, 2005 at 10:40:21AM -0500, Steven M. Bellovin wrote:
>>What, precisely, is the problem?  What is there about tmpfs that a 
>>application can detect?
> Linux's libc relies on knowledge of the internal structure of directory
> entries rather than manipulating them with the appropriate system calls.
> This causes chaos for those porting filesystems to Linux (e.g. XFS, JFS),
> as well as for those emulating Linux on other systems (e.g. us) or serving
> directories to Linux over network filesystems (because the Linux clients
> don't translate the structure of directories on read(2) either).

This implies that the linux_sys_read syscall (and friends) needs to know
if it's reading from a directory, and if so, do the getdents dance itself.
This would be filesystem independent.  And ugly as hell.

Matt Thomas                     email:
3am Software Foundry              www:
Cupertino, CA              disclaimer: I avow all knowledge of this message.