From: Frank van Maarseveen <frankvm@frankvm.com>
To: Linux NFS mailing list <nfs@lists.sourceforge.net>
Subject: 2.6.19.3 client locking bug upon server reboot
Date: Mon, 26 Feb 2007 15:15:17 +0100 [thread overview]
Message-ID: <20070226141517.GA22552@janus> (raw)
2.6.19.3, NFS V3, portmap V2, stat V1, nlm, all UDP
one server, three clients:
client1 has the lock
client2 wants the lock (fcntl blocks)
client3 will try to lock right after server has rebooted and started everything
On the server, /etc/rc2.d/S06xxxx is created to start a
tcpdump -i eth0 -p -w /tmp/log -s 1500 >/dev/null 2>&1 &
upon the next reboot right after eth0 becomes up.
I type alt-sysrq-b on the server after a few "sync" commands. After >5
minutes client1 releases the lock and client3 obtains the lock. A few
seconds later client3 releases the lock.
nothing happens
client2 did not try to obtain a lock anyhow since server reboot. Instead,
it hangs in rpc_wait_bit_interruptible(), only kill -9 could kill it.
The log written by tcpdump has been analyzed afterwards using wireshark
(t=<time since start>):
t=10 server->(all 3 clients): portmap getport STAT, all clients reply
server->(all 3 clients): STAT notify, all clients reply
client1->server: portmap getport NLM, server replies
client1->server: NLM lock, server replies.
t=15 client3->server: portmap getport NLM, server replies
client3->server: NLM lock, server says: NLM_DENIED_GRACE_PERIOD
t=20 client3->server: NLM lock, server says: NLM_DENIED_GRACE_PERIOD
t=25 client3->server: NLM lock, server says: NLM_DENIED_GRACE_PERIOD
t=30 client3->server: NLM lock, server says: NLM_DENIED_GRACE_PERIOD
t=35 client3->server: NLM lock, server says: NLM_DENIED_GRACE_PERIOD
t=40 client3->server: NLM lock, server says: NLM_DENIED_GRACE_PERIOD
t=45 client3->server: NLM lock, server says: NLM_DENIED_GRACE_PERIOD
t=50 client3->server: NLM lock, server says: NLM_DENIED_GRACE_PERIOD
t=55 client3->server: NLM lock, server says: NLM_BLOCKED
t=85 client3->server: portmap getport NLM, server replies
t=115 client3->server: NLM lock, server says: NLM_BLOCKED
[...]
t=383 client1->server: portmap getport NLM, server replies
client1->server: NLM unlock, server replies
server->client3: portmap getport NLM, client replies
server->client3: NLM NULL, client replies
server->client3: NLM GRANTED_MSG
client3->server: portmap getport NLM, server replies
client3->server: NLM NULL, server replies.
client3->server: NLM GRANTED_RES, server replies.
client3->server: reply for NLM GRANTED_MSG
t=390 client3->server: portmap getport NLM, server replies
client3->server: NLM unlock, server replies.
Notice the absence of any client2 traffic for t>10. There is no
interesting traffic around t=10 whatsoever for client2 other than what
has been mentioned. This bug is probably reproducable without the third
client but anyway, the above is what happened during the test.
--
Frank
-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
NFS maillist - NFS@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/nfs
next reply other threads:[~2007-02-26 14:15 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-26 14:15 Frank van Maarseveen [this message]
2007-03-02 20:15 ` 2.6.x client locking bug upon server reboot (2) Frank van Maarseveen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20070226141517.GA22552@janus \
--to=frankvm@frankvm.com \
--cc=nfs@lists.sourceforge.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox