Bug 204890 - named pipes (FIFOs) not seen as such over NFS
Summary: named pipes (FIFOs) not seen as such over NFS
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: 10.2-STABLE
Hardware: amd64 Any
: --- Affects Many People
Assignee: freebsd-bugs mailing list
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-11-29 06:47 UTC by Mikhail Teterin
Modified: 2015-11-29 18:21 UTC (History)
2 users (show)

See Also:


Attachments
tcpdump-capture of NFS-client doing an ls (1.33 KB, application/vnd.tcpdump.pcap)
2015-11-29 18:21 UTC, Mikhail Teterin
no flags Details

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Description Mikhail Teterin freebsd_committer 2015-11-29 06:47:31 UTC
A named pipe created on an NFS-server is not seen as such on NFS-clients.

For example, I have a filesystem mounted as /green on an NFS-server (running 10.2-STABLE #0 r289145). After creating a FIFO there with mkfifo, I can see it properly:

prw-r--r--  1 mi  wheel  0 Nov 29 00:05 /green/tmp/test

However, an NFS-client (running 10.2-STABLE FreeBSD 10.2-STABLE #0 r291365) sees the same entry differently:

?rw-r--r--  1 mi  wheel  0 Nov 29 00:05 /green/tmp/test
(note the question mark for type...)

stat(1) demonstrates other differences:

NFS-server:
92 74636334 prw-r--r-- 1 mi wheel 0 0 "Nov 29 00:05:51 2015" "Nov 29 00:05:51 2015" "Nov 29 00:05:51 2015" "Nov 29 00:05:51 2015" 16384 0 0 /green/tmp/test

NFS-client:
973143811 74636334 ?rw-r--r-- 1 mi wheel 4294967295 0 "Nov 29 00:05:51 2015" "Nov 29 00:05:51 2015" "Nov 29 00:05:51 2015" "Dec 31 18:59:59 1969" 16384 0 0 /green/tmp/test
Comment 1 Mikhail Teterin freebsd_committer 2015-11-29 06:51:26 UTC
FWIW, I do not see the same problem on another pair of servers -- both running 10.1-STABLE.
Comment 2 Kurt Jaeger freebsd_committer 2015-11-29 09:16:18 UTC
Tested: nfs server 10.1p24, nfs client 10.2p7, sees:

prw-rw-r--  1 root  wheel  0 Nov 29 10:12 bla
Comment 3 Mikhail Teterin freebsd_committer 2015-11-29 18:21:44 UTC
Created attachment 163657 [details]
tcpdump-capture of NFS-client doing an ls

Attaching the tcpdump-capture as requested by Rick by e-mail.

Meanwhile, I tested the two computers mounting their own shares. The old:

   % mount 192.168.1.8:/green /mnt
   % ls -l /mnt/tmp/test
   ?rw-r--r--  1 mi  wheel  0 29 лис 00:05 /mnt/tmp/test

The new:

   % mount 192.168.1.2:/spare /mnt
   % mkfifo /spare/fifo
   % ls -l /spare/fifo /mnt/fifo
   prw-r--r--  1 root  wheel  0 29 лис 13:12 /mnt/fifo
   prw-r--r--  1 root  wheel  0 29 лис 13:12 /spare/fifo

I then mounted the other way -- with the old system being the NFS-client -- and could not see the bug either. I think, this points conclusively at a bug in NFS-server of 10.2-STABLE #0 r289145 -- which must've been fixed by the time of 
r291365.

I'll rebuild the kernel on the old server to confirm...