Re: [PATCH] cowlinks v2

Eric W. Biederman
2004-04-03T18:40:32Z

Jamie Lokier <jamie@shareable.org> writes:

> Here's a tricky situation:
>
> 1. A file is cowlinked. Then each cowlink is mmap()'d, one per process.
>
> 2. At this point both mappings share the same pages in RAM.

Why they have different inodes?

> 3. Then one of the cowlinks is written to...

I would not worry about sharing page cache entries unless this becomes
a common case. If you want to avoid the hit of rereading the file when
you have a cow copy it should be simple enough to walk through the list
of cow copies and see if anyone else has it open.

Eric