more weird bugs with mmap-ing via NFS

Mikhail Teterin mi+mx at
Wed Mar 22 02:08:19 UTC 2006

вівторок 21 березень 2006 20:53, Matthew Dillon Ви написали:
>     Ah ha.  That's the problem.  I don't know why you are getting a write
>     error, but that is preventing the client from cleaning out the dirty
>     buffers. The number of dirty buffers continues to rise and the client
>     is just cycling on them over and over trying to write them out,
>     because it's just as confused about why it is getting a permission
>     denied error as you are

Well, whatever it is, this means a big juicy bug, does not it? I mean, the 
client should not get "confused" like this _ever_, but _especially_, when it 
is talking to a fellow FreeBSD NFS-server.

>     If you can figure out why you are getting that error, and fix it, it
>     will solve the problem.

Even if I do, and it is something stupid, why is vmstat stalling the entire 
system, when this is happening?

>     It is an NFS error returned by the server, not 
>     a firewall issue.  So it probably has something to do either with the
>     way the filesystem being exported was mounted on the server, or the
>     export line in /etc/exports.

The export line has no options, it is simply: ``/backup''.

The file was created alright, and written to for some time, so it is not file 
permissions either.

The fs is mounted as:

	/dev/amrd0 on /backup (ufs, NFS exported, local)

(no softupdates). It was created with `-O1 -b 65536 -f 8192' as it is intended 
for large files and needs no ACLs (hence no UFS1).

There is nothing in dmesg either, and the same backup script running locally 
on the NFS server (and outputing to the same fs) has no problems.

Thanks! Yours,


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