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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.