Subject: Re: problem with tmpfs and linux emulation?
To: Bill Studenmund <>
From: Perry E. Metzger <>
List: current-users
Date: 11/12/2005 12:58:41
Bill Studenmund <> writes:
> On Thu, Nov 10, 2005 at 10:50:07PM +0000, Matthias Scheler wrote:
>> In article <>,
>> 	Matt Thomas <> writes:
>> > 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.
>> Yes, indeed.
>> > This would be filesystem independent.  And ugly as hell.
>> Why? Figuring out that it is a directory can be done by looking on the vnode.
> I think the problem is that the layering doesn't make this convenient. The 
> level that can easily see the vnode, the vn layer, is deep past the place 
> where we abstract away the emulation. So we either add a hook to determine 
> emulation, teach all emulations how to read directories, or cook up a way 
> so that linux opens of directories get a different vn vector which will do 
> the right thing.

Could the linux emulation version of open do an implicit fstat as its
first operation?