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author | Chuck Lever <chuck.lever@oracle.com> | 2008-12-04 14:20:46 -0500 |
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committer | J. Bruce Fields <bfields@citi.umich.edu> | 2009-01-06 11:53:51 -0500 |
commit | 29ed1407ed81086b778ebf12145b048ac3f7e10e (patch) | |
tree | 35523669465a1a37f969054e1c3d7530582701fc /include/linux/lockd | |
parent | f47534f7f0ac7727e05ec4274b764b181df2cf7f (diff) | |
download | linux-stable-29ed1407ed81086b778ebf12145b048ac3f7e10e.tar.gz linux-stable-29ed1407ed81086b778ebf12145b048ac3f7e10e.tar.bz2 linux-stable-29ed1407ed81086b778ebf12145b048ac3f7e10e.zip |
NSM: Support IPv6 version of mon_name
The "mon_name" argument of the NSMPROC_MON and NSMPROC_UNMON upcalls
is a string that contains the hostname or IP address of the remote peer
to be notified when this host has rebooted. The sm-notify command uses
this identifier to contact the peer when we reboot, so it must be
either a well-qualified DNS hostname or a presentation format IP
address string.
When the "nsm_use_hostnames" sysctl is set to zero, the kernel's NSM
provides a presentation format IP address in the "mon_name" argument.
Otherwise, the "caller_name" argument from NLM requests is used,
which is usually just the DNS hostname of the peer.
To support IPv6 addresses for the mon_name argument, we use the
nsm_handle's address eye-catcher, which already contains an appropriate
presentation format address string. Using the eye-catcher string
obviates the need to use a large buffer on the stack to form the
presentation address string for the upcall.
This patch also addresses a subtle bug.
An NSMPROC_MON request and the subsequent NSMPROC_UNMON request for the
same peer are required to use the same value for the "mon_name"
argument. Otherwise, rpc.statd's NSMPROC_UNMON processing cannot
locate the database entry for that peer and remove it.
If the setting of nsm_use_hostnames is changed between the time the
kernel sends an NSMPROC_MON request and the time it sends the
NSMPROC_UNMON request for the same peer, the "mon_name" argument for
these two requests may not be the same. This is because the value of
"mon_name" is currently chosen at the moment the call is made based on
the setting of nsm_use_hostnames
To ensure both requests pass identical contents in the "mon_name"
argument, we now select which string to use for the argument in the
nsm_monitor() function. A pointer to this string is saved in the
nsm_handle so it can be used for a subsequent NSMPROC_UNMON upcall.
NB: There are other potential problems, such as how nlm_host_rebooted()
might behave if nsm_use_hostnames were changed while hosts are still
being monitored. This patch does not attempt to address those
problems.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Diffstat (limited to 'include/linux/lockd')
-rw-r--r-- | include/linux/lockd/lockd.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h index 54dbb458e73c..d3c7247d23e8 100644 --- a/include/linux/lockd/lockd.h +++ b/include/linux/lockd/lockd.h @@ -79,6 +79,7 @@ struct nlm_host { struct nsm_handle { struct list_head sm_link; atomic_t sm_count; + char *sm_mon_name; char *sm_name; struct sockaddr_storage sm_addr; size_t sm_addrlen; |