Hi Bruce,
FWIW, I don't think dtrace does/did what NASA is asking for, but that's
really irrelevant. The locks in NFSv4 are application specific locks,
not generic kernel locks, so a service looking for spinlocks, mutexes,
etc... wouldn't really be helpful I don't think. However implementing a
/sys/class, debugfs thingy that dumped the nfsv4 locks held is fairly
simple, although I would think there are security implications.
Tom
On 8/7/2018 3:34 PM, J. Bruce Fields wrote:
On Thu, Aug 02, 2018 at 08:50:20PM +0200, Cedric Blancher wrote:
Solaris and FreeBSD dtrace facility supports this functionality.
Unfortunately, Linux rejected dtrace for license issues, and instead
did... nothing.
I didn't think was this sort of question tracing was designed to
answer--it's a question about the system state at a given time (who
holds what locks), rather than a list of events. But I know nothing
about dtrace.
--b.
Ced
On 10 July 2018 at 04:28, Peter Scott <pjscott@xxxxxxxxxxxx> wrote:
Hello. I am with the institutional hosting service at NASA's Jet Propulsion
Laboratory and we have been trying to find the answer to an apparently
simple question.
We are running an NFSv4 server on Centos 7 and we need to get the server to
tell us which files it thinks are locked by which clients. This is because
we have observed failure modes where something apparently has a lock
(because attempting to lock the file again blocks) but we can't find a
client that has the lock. Finding out what the server believes would be
critical to troubleshooting this.
We tracked down Trond Myklebust and Neil Brown and conversation suggests
that this is a function that is (a) not currently available and (b)
reasonable to ask for. So this is me suggesting that an interface be
provided to have knfsd output its list of locked files and clients.
Regards,
Peter Scott
Office of the CIO
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Cedric Blancher <cedric.blancher@xxxxxxxxx>
[https://plus.google.com/u/0/+CedricBlancher/]
Institute Pasteur
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Thomas Tucker
President
Open Grid Computing, Inc.
(m) 512-826-7622
(o) 512-220-3434
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
