NFS client/buffer cache deadlock

[Marc Olzheim]

On Wed, Apr 27, 2005 at 03:06:27PM -0400, Brian Fundakowski Feldman wrote:
> > How can I tell whether it uses transactions ?
> 
> I am not sure -- it should with NFSv3 though.  Does "mount -v" tell
> you anything more detailed?  I suppose that nfsstat may also be used
> -- the "commit" count should only increase when it does an NFSv3
> commit operation.
> 
> > The NFS server is mounted with:
> > 
> > mount_nfs -c -P -a 0 -r 8192 -w 8192 -i -o rw,noatime,nointr host:/path /nfs/host/path
> 
> So the only really visible difference is 6 nfsiod versus 20 nfsiod.  I
> think if you increased the nfsiod on that 4.x box to something much
> higher it would deadlock the same, then, assuming that all else is
> equal.

Well, I took on that challenge and although it seems that the machine
completely hangs itself up for a while, it snaps out of it after it is
done.

tehethereal tells me it is NFSv3, and the commits increase:

baroque:/se3/spiderbak>nfsstat 
Client Info:
Rpc Counts:
  Getattr   Setattr    Lookup  Readlink      Read     Write    Create    Remove
    15272     20119   3401842     82797 548076917    594394     43551     42697
   Rename      Link   Symlink     Mkdir     Rmdir   Readdir  RdirPlus    Access
    13077        27     11573      2957      2959     17178         0  24938388
    Mknod    Fsstat    Fsinfo  PathConf    Commit    GLease    Vacate     Evict
        0     61788        14         0    191593         0         0         0
Rpc Info:
 TimedOut   Invalid X Replies   Retries  Requests
        0         0    210711    330710 577517143
Cache Info:
Attr Hits    Misses Lkup Hits    Misses BioR Hits    Misses BioW Hits    Misses
376190541  24213879  94021997   3401840 325304623 545060579    699854    594394
BioRLHits    Misses BioD Hits    Misses DirE Hits    Misses
  3051125     82797     88340     17145     42013         0

Server Info:
  Getattr   Setattr    Lookup  Readlink      Read     Write    Create    Remove
        0         0         0         0         0         0         0         0
   Rename      Link   Symlink     Mkdir     Rmdir   Readdir  RdirPlus    Access
        0         0         0         0         0         0         0         0
    Mknod    Fsstat    Fsinfo  PathConf    Commit    GLease    Vacate     Evict
        0         0         0         0         0         0         0         0
Server Ret-Failed
                0
Server Faults
            0
Server Cache Stats:
   Inprog      Idem  Non-idem    Misses
        0         0         0         0
Server Lease Stats:
   Leases     PeakL   GLeases
        0         0         0
Server Write Gathering:
 WriteOps  WriteRPC   Opsaved
        0         0         0
baroque:/se3/spiderbak>/home/marcolz/src/writev 100 foo0
nfsstat
baroque:/se3/spiderbak>nfsstat
Client Info:
Rpc Counts:
  Getattr   Setattr    Lookup  Readlink      Read     Write    Create    Remove
    15272     20119   3401879     82797 548082677    607194     43552     42697
   Rename      Link   Symlink     Mkdir     Rmdir   Readdir  RdirPlus    Access
    13077        27     11573      2957      2959     17178         0  24938698
    Mknod    Fsstat    Fsinfo  PathConf    Commit    GLease    Vacate     Evict
        0     61788        14         0    193252         0         0         0
Rpc Info:
 TimedOut   Invalid X Replies   Retries  Requests
        0         0    210711    331410 577537710
Cache Info:
Attr Hits    Misses Lkup Hits    Misses BioR Hits    Misses BioW Hits    Misses
376195207  24214181  94022936   3401877 325306477 545066339    699854    607194
BioRLHits    Misses BioD Hits    Misses DirE Hits    Misses
  3051125     82797     88340     17145     42013         0

Server Info:
  Getattr   Setattr    Lookup  Readlink      Read     Write    Create    Remove
        0         0         0         0         0         0         0         0
   Rename      Link   Symlink     Mkdir     Rmdir   Readdir  RdirPlus    Access
        0         0         0         0         0         0         0         0
    Mknod    Fsstat    Fsinfo  PathConf    Commit    GLease    Vacate     Evict
        0         0         0         0         0         0         0         0
Server Ret-Failed
                0
Server Faults
            0
Server Cache Stats:
   Inprog      Idem  Non-idem    Misses
        0         0         0         0
Server Lease Stats:
   Leases     PeakL   GLeases
        0         0         0
Server Write Gathering:
 WriteOps  WriteRPC   Opsaved
        0         0         0
baroque:/se3/spiderbak>

Marc
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