Re: cdrecord produces broken CDs on -CURRENT: The Answer !

2001-11-29 Thread Peter Wemm

Christoph Herrmann wrote:
 
 The Problem was the use of vfs.ioopt=2 !
 As long as vfs.ioopt is 1 or 2 the CDs are broken and with 
 vfs.ioopt=0 the CDs are o.k.
 
 I didn't see any other problems with the use of vfs.ioopt=2,
 especially no Filesystem corruption :-). Are there other known
 problems withs vfs.ioopt != 0 ?

Yes, it breaks read(2) semantics totally.  With a traditional system, if
you read something into your buffer, it never changes.

With vfs.ioopt = 1, that read may be turned into a mmap() if the conditions
are right.  Specifically, if you are doing a page aligned read of one or more
pages, your original page will be released and you will get a copy-on-write
page mapped in.

The problem with that is that it is copy-on-write for *you*, not everybody
else.  If somebody else subsequently changes the file, your buffer will
automagically change.

This is why it is off.  The NFS zerocopy patches made some changes to the
VM and buffer system to fix this.  It was pretty simple to fix if I recall
correctly.

Cheers,
-Peter
--
Peter Wemm - [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED]
All of this is for nothing if we don't go to the stars - JMS/B5


To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-current in the body of the message



cdrecord produces broken CDs on -CURRENT: The Answer !

2001-11-28 Thread Christoph Herrmann


The Problem was the use of vfs.ioopt=2 !
As long as vfs.ioopt is 1 or 2 the CDs are broken and with 
vfs.ioopt=0 the CDs are o.k.

I didn't see any other problems with the use of vfs.ioopt=2,
especially no Filesystem corruption :-). Are there other known
problems withs vfs.ioopt != 0 ?



Ciao


Christoph :-)



To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-current in the body of the message



Re: cdrecord produces broken CDs on -CURRENT: The Answer !

2001-11-28 Thread Alexander Leidinger

On 28 Nov, Christoph Herrmann wrote:
 
 The Problem was the use of vfs.ioopt=2 !
 As long as vfs.ioopt is 1 or 2 the CDs are broken and with 
 vfs.ioopt=0 the CDs are o.k.
 
 I didn't see any other problems with the use of vfs.ioopt=2,
 especially no Filesystem corruption :-). Are there other known
 problems withs vfs.ioopt != 0 ?

At the time I tested this, native netscape died with a bus error (or
segfault?, don't remember).

Bye,
Alexander.

-- 
   There's no place like ~

http://www.Leidinger.net   Alexander @ Leidinger.net
  GPG fingerprint = C518 BC70 E67F 143F BE91  3365 79E2 9C60 B006 3FE7


To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-current in the body of the message