Re: [9fans] kfs locks

[jmk@plan9.bell-labs.com]

On Sun Mar  7 15:22:37 EST 2004, dvd@davidashen.net wrote:
> > in a previous message, with various debugging prints turned on
> > and inserted, there seemed to be driver requests to abort a command.
> 
> write is being aborted, because it is asked to write at offset 
> not present on the disk. It looks like the in-memory structure 
> is corrupt.
> 
> > you don't seem to see the problem unless you power cycle,
> > and although i don't use it as much as i did, i still use kfs a
> > fair bit (and i do sometimes just switch off that machine),
> > and i don't see similar problems.
> > now, it's quite likely that i'm running an older version of kfs,
> 
> It is quite likely that your machine is slower. If I slow down
> the kfs or kernel code by inserting more debugging, the problem
> disappears because the structure is flushed before being overwritten.
> 
> > actual cause of wrenwrite errors before trying to guess what and
> > where the problem might be!
> 
> offsets are negative vlongs. 

The offset is supposed to be checked way before getting to the
ATA driver:
1) the write and seek system calls check the offset is not negative;
2) the higher level of the disc driver checks the address requested
   is within the partition.

What does your partition table look like?