more weird bugs with mmap-ing via NFS
mi+mx at aldan.algebra.com
Wed Mar 22 18:13:22 UTC 2006
середа 22 березень 2006 12:23, Matthew Dillon Ви написали:
> My guess is that you are exporting the filesystem as a particular
> user id that is not root (i.e. you do not have -maproot=root: in the
> exports line on the server).
Yes, indeed, re-exporting with -maproot=0 leads to normal behavior. Thanks for
Here are the stats: As the program is working hard, the incoming traffic on
the client is about 200Kb/s (I guess, all those not yet existant pages being
faulted in) and the outgoing -- about 7Kb/s with occasional spikes to 8Mb/s
(I guess, this is when the flushing takes place).
> What is likely happening is that the NFS client is trying to push out
> the pages using the root uid rather then the user uid. This is a
> highly probable circumstance for VM pages because once they get
> disassociated from the related buffer cache buffer, the cred information
> for the last process to modify the related VM pages is lost. When the
> kernel tries to flush the pages out it winds up using root creds.
So mmap is just a more "reliable" way to trigger this problem, right?
Is not this, like, a major bug? A file can be opened, written to for a while,
and then -- at a semi-random moment -- the log will drop across the road?
Thanks a lot to all concerned for helping solve this problem. Yours,
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