more weird bugs with mmap-ing via NFS

Matthew Dillon dillon at
Wed Mar 22 01:54:00 UTC 2006

:>    tcpdump -s 4096 -n -i <interface> -l port 2049
:Now I am thoroughly confused, the lines are very repetative:
:tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
:listening on em0, link-type EN10MB (Ethernet), capture size 4096 bytes
:20:41:55.788436 IP > reply ok 60
:20:41:55.788502 IP > 1472 write 
:fh 1090,6005/15141914 5120 (5120) bytes @ 4943872
:20:41:55.788811 IP > reply ok 60 
:write ERROR: Permission denied
:20:41:55.788872 IP > 1472 write 
:fh 1090,6005/15141914 5120 (5120) bytes @ 4947968
:The only reason for "permission denied" I know, is the firewall, but neither 
:the server nor the client even have ipfw loaded...
:	-mi

    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 :-)

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

					Matthew Dillon 
					<dillon at>

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