Re: 2.4.0-test10-pre3:Oops in mm/filemap.c:filemap_write_pa

From: Linus Torvalds (torvalds@transmeta.com)
Date: Mon Oct 23 2000 - 12:33:15 EST


In article <14832.39946.657679.861952@charged.uio.no>,
Trond Myklebust <trond.myklebust@fys.uio.no> wrote:
>
>As for simply settling for a self-consistent mmap() rather than
>tackling the problem of rereading; the main crime is that you're
>rendering file locking unusable.

This is not a crime.

Anybody who uses file locking over NFS is buggy and nobody sane should
expect it to work reliably. There are good reasons why mail agents etc
depend on other kinds of locking over NFS.

Furthermore, anybody who expects file locking to work _anywhere_ (ie
including local filesystems) in the presense of file mapping is just so
out to lunch that it's ridiculous.

Neither of these issues have anything to do with Linux. They are just
statements of fact.

And yes, I know that file locking can try to be nice in both of these
cases. I know that there are systems that try to revert shared mappings
etc upon file locking (or not allow file locking at all if mappings are
present). Linux is not one of them, and never has been. Neither are
most UNIXes out there.

                Linus

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