NFS client/buffer cache deadlock

[Marc Olzheim]

On Wed, Apr 27, 2005 at 03:41:44PM -0400, Brian Fundakowski Feldman wrote:
> Alright, thanks for testing.  So the same bug exists in 4.x but may
> not actually deadlock the buffer cache in the same circumstances.
> If you feel like playing with it anymore, I would expect a certain
> write block size, maximum nfsiod, and total file size being written
> wouldn't be too hard to find that would deadlock 4.x, too.

20 is the maximum number it is willing to start. 21 and above it tells
me:

baroque:~# nfsiod -n 21  
nfsiod: nfsiod count 21; reset to 1
baroque:~#

:-P

Btw.: CPU time was nicely divided amoungst all of the nfsiod's when
doing the writev:

root    87373  0.0  0.0   212   32  ??  I     9:11PM   0:00.18 nfsiod -n 20
root    87372  0.0  0.0   212   32  ??  I     9:11PM   0:00.16 nfsiod -n 20
root    87371  0.0  0.0   212   32  ??  I     9:11PM   0:00.16 nfsiod -n 20
root    87370  0.0  0.0   212   32  ??  I     9:11PM   0:00.18 nfsiod -n 20
root    87369  0.0  0.0   212   32  ??  I     9:11PM   0:00.18 nfsiod -n 20
root    87368  0.0  0.0   212   32  ??  I     9:11PM   0:00.19 nfsiod -n 20
root    87367  0.0  0.0   212   32  ??  I     9:11PM   0:00.18 nfsiod -n 20
root    87366  0.0  0.0   212   32  ??  I     9:11PM   0:00.18 nfsiod -n 20
root    87365  0.0  0.0   212   32  ??  I     9:11PM   0:00.17 nfsiod -n 20
root    87364  0.0  0.0   212   32  ??  I     9:11PM   0:00.17 nfsiod -n 20
root    87363  0.0  0.0   212   32  ??  I     9:11PM   0:00.19 nfsiod -n 20
root    87362  0.0  0.0   212   32  ??  I     9:11PM   0:00.19 nfsiod -n 20
root    87361  0.0  0.0   212   32  ??  I     9:11PM   0:00.20 nfsiod -n 20
root    87360  0.0  0.0   212   32  ??  I     9:11PM   0:00.20 nfsiod -n 20
root    87359  0.0  0.0   212   32  ??  I     9:11PM   0:00.20 nfsiod -n 20
root    87358  0.0  0.0   212   32  ??  I     9:11PM   0:00.19 nfsiod -n 20
root    87357  0.0  0.0   212   32  ??  I     9:11PM   0:00.19 nfsiod -n 20
root    87356  0.0  0.0   212   32  ??  I     9:11PM   0:00.21 nfsiod -n 20
root    87355  0.0  0.0   212   32  ??  I     9:11PM   0:00.21 nfsiod -n 20
root    87354  0.0  0.0   212   32  ??  I     9:11PM   0:00.23 nfsiod -n 20

Marc
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