On Jan 30, 2009, at Jan 30, 2009, 3:32 PM, Trond Myklebust wrote:
On Fri, 2009-01-30 at 15:10 -0500, Chuck Lever wrote:
Apparently a lot of people need to completely disable IPv6 on their
distribution-built systems, and they do this by blacklisting the
ipv6 module. This causes lockd_up(), and thus NFS mounts, to fail
in all cases (even for IPv4 mounts) if CONFIG_IPV6_MODULE and
CONFIG_SUNRPC_REGISTER_V4 is set.
As a workaround, change lockd to use an AF_INET6 listener only if
IPv6
is built into the kernel.
This allows IPv6 NFS testing to continue, while supporting legacy
IPv4
NFS as before. In the meantime, we will pursue a long-term fix so
that
lockd (and eventually NFSD) will be able to handle this case
correctly.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Tested-by: Steve Dickson <steved@xxxxxxxxxx>
---
fs/lockd/svc.c | 11 ++++++-----
1 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index 64f1c31..39ec7f2 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -54,14 +54,15 @@ unsigned long nlmsvc_timeout;
/*
* If the kernel has IPv6 support available, always listen for
- * both AF_INET and AF_INET6 requests.
+ * both AF_INET and AF_INET6 requests. To avoid breaking lockd
+ * if the ipv6 module was built but has been blacklisted, enable
+ * this only if IPv6 support is built into the kernel.
*/
-#if (defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)) && \
- defined(CONFIG_SUNRPC_REGISTER_V4)
+#if defined(CONFIG_IPV6) && defined(CONFIG_SUNRPC_REGISTER_V4)
static const sa_family_t nlmsvc_family = AF_INET6;
-#else /* (CONFIG_IPV6 || CONFIG_IPV6_MODULE) &&
CONFIG_SUNRPC_REGISTER_V4 */
+#else /* CONFIG_IPV6 && CONFIG_SUNRPC_REGISTER_V4 */
static const sa_family_t nlmsvc_family = AF_INET;
-#endif /* (CONFIG_IPV6 || CONFIG_IPV6_MODULE) &&
CONFIG_SUNRPC_REGISTER_V4 */
+#endif /* CONFIG_IPV6 && CONFIG_SUNRPC_REGISTER_V4 */
/*
* These can be set at insmod time (useful for NFS as root
filesystem),
That issue will affect the NFSv4 callback server too.
I'll submit a separate patch for that.
How about using something like a 'symbol_request(ipv6_getsockopt)' to
probe whether or not IPv6 is available.
That's a good idea. I was about to go looking for the right way to
check if the module is available.
I've been discussing this with Steve. He'd like some way for lockd to
recover if only an IPv4 mount is requested, but the logic to do this
(and to report real errors on IPv6 mounts, and to handle the NFSD
cases) might get complicated. Plus, once we start lockd with an
AF_INET listener, we are stuck with IPv4-only until lockd is restarted
from scratch.
I think we want any issues in this area to be handled at mount/export
time, and not specifically by lockd or the callback server. What do
you think?
--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
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