Subject: Re: cp(1) vs. UVM/UBC
To: Ignatios Souvatzis <>
From: Matthias Scheler <>
List: tech-userlevel
Date: 07/19/2001 10:44:03
On Thu, Jul 19, 2001 at 10:40:53AM +0200, Ignatios Souvatzis wrote:
> There are other file systems with potential problems, if I recall right...
> e.g., the DOS\0 and DOS\1 variants of adosfs, which always have some=20
> metadata in their datablocks,

It's DOS\0, DOS\2 and DOS\4 which have metadata in the data blocks.

> ... so for this case, data copying always happens. (Chuck?)

Does mmap() do that transperantly?

> Maybe we need to disable mmap()ing for such filesystems inside the kernel,
> and make cp do the right thing if mmap fails? Is this possible?

Sounds reasonable for "cp". But what about other applications?

	Kind regards

Matthias Scheler