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2009-01-06NSM: Release nsmhandle in nlm_destroy_hostChuck Lever
The nsm_handle's reference count is bumped in nlm_lookup_host(). It should be decremented in nlm_destroy_host() to make it easier to see the balance of these two operations. Move the nsm_release() call to fs/lockd/host.c. The h_nsmhandle pointer is set in nlm_lookup_host(), and never cleared. The nlm_destroy_host() function is never called for the same nlm_host twice, so h_nsmhandle won't ever be NULL when nsm_unmonitor() is called. All references to the nlm_host are gone before it is freed. We can skip making h_nsmhandle NULL just before the nlm_host is deallocated. It's also likely we can remove the h_nsmhandle NULL check in nlmsvc_is_client() as well, but we can do that later when rearchitect- ing the nlm_host cache. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-01-06NLM: Move the public declaration of nsm_monitor() to lockd.hChuck Lever
Clean up. Make the nlm_host argument "const," and move the public declaration to lockd.h with other NSM public function (nsm_release, eg) and global variable declarations. Add a documenting comment. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-01-06NSM: Make sure to return an error if the SM_MON call result is not zeroChuck Lever
The nsm_monitor() function reports an error and does not set sm_monitored if the SM_MON upcall reply has a non-zero result code, but nsm_monitor() does not return an error to its caller in this case. Since sm_monitored is not set, the upcall is retried when the next NLM request invokes nsm_monitor(). However, that may not come for a while. In the meantime, at least one NLM request will potentially proceed without the peer being monitored properly. Have nsm_monitor() return an error if the result code is non-zero. This will cause all NLM requests to fail immediately if the upcall completed successfully but rpc.statd returned an error. This may be inconvenient in some cases (for example if rpc.statd cannot complete a proper DNS reverse lookup of the hostname), but will make the reboot monitoring service more robust by forcing such issues to be corrected by an admin. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-01-06NSM: Remove BUG_ON() in nsm_monitor()Chuck Lever
Clean up: Remove the BUG_ON() invocation in nsm_monitor(). It's not likely that nsm_monitor() is ever called with a NULL host pointer, and the code will die anyway if host is NULL. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-01-06NLM: Remove redundant printk() in nlmclnt_lock()Chuck Lever
The nsm_monitor() function already generates a printk(KERN_NOTICE) if the SM_MON upcall fails, so the similar printk() in the nlmclnt_lock() function is redundant. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-01-06NSM: Use sm_name instead of h_name in nsm_monitor() and nsm_unmonitor()Chuck Lever
Clean up: Use the sm_name field for reporting the hostname in nsm_monitor() and nsm_unmonitor(), just as the other functions in fs/lockd/mon.c do. The h_name field is just a copy of the sm_name pointer. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-01-06NSM: Support IPv6 version of mon_nameChuck Lever
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>
2009-01-06NSM: convert printk(KERN_DEBUG) to a dprintk()Chuck Lever
Clean up: make the printk(KERN_DEBUG) in nsm_mon_unmon() a dprintk, and add another dprintk to note if creating an RPC client for the upcall failed. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-01-06NSM: Use C99 structure initializer to initialize nsm_argsChuck Lever
Clean up: Use a C99 structure initializer instead of open-coding the initialization of nsm_args. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-01-06NLM: Add helper to handle IPv4 addressesChuck Lever
Clean up: introduce a helper function to generate IPv4 addresses using the same style as the IPv6 helper function we just added. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-01-06NLM: Support IPv6 scope IDs in nlm_display_address()Chuck Lever
Scope ID support is needed since the kernel's NSM implementation is about to use these displayed addresses as a mon_name in some cases. When nsm_use_hostnames is zero, without scope ID support NSM will fail to handle peers that contact us via a link-local address. Link-local addresses do not work without an interface ID, which is stored in the sockaddr's sin6_scope_id field. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-01-06NLM: Remove AF_UNSPEC arm in nlm_display_address()Chuck Lever
AF_UNSPEC support is no longer needed in nlm_display_address() now that a presentation address is no longer generated for the h_srcaddr field. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-01-06NLM: Remove address eye-catcher buffers from nlm_hostChuck Lever
The h_name field in struct nlm_host is a just copy of h_nsmhandle->sm_name. Likewise, the contents of the h_addrbuf field should be identical to the sm_addrbuf field. The h_srcaddrbuf field is used only in one place for debugging. We can live without this until we get %pI formatting for printk(). Currently these buffers are 48 bytes, but we need to support scope IDs in IPv6 presentation addresses, which means making the buffers even larger. Instead, let's find ways to eliminate them to save space. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-01-06lockd: set svc_serv->sv_maxconn to a more reasonable value (try #3)Jeff Layton
The default method for calculating the number of connections allowed per RPC service arbitrarily limits single-threaded services to 80 connections. This is too low for services like lockd and artificially limits the number of TCP clients that it can support. Have lockd set a default sv_maxconn value to 1024 (which is the typical default value for RLIMIT_NOFILE. Also add a module parameter to allow an admin to set this to an arbitrary value. Signed-off-by: Jeff Layton <jlayton@redhat.com> Acked-by: Neil Brown <neilb@suse.de> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-12-30Merge branch 'devel' into nextTrond Myklebust
2008-12-23NLM: allow lockd requests from an unprivileged portChuck Lever
If the admin has specified the "noresvport" option for an NFS mount point, the kernel's NFS client uses an unprivileged source port for the main NFS transport. The kernel's lockd client should use an unprivileged port in this case as well. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23lockd: convert reclaimer thread to kthread interfaceJeff Layton
My understanding is that there is a push to turn the kernel_thread interface into a non-exported symbol and move all kernel threads to use the kthread API. This patch changes lockd to use kthread_run to spawn the reclaimer thread. I've made the assumption here that the extra module references taken when we spawn this thread are unnecessary and removed them. I've also added a KERN_ERR printk that pops if the thread can't be spawned to warn the admin that the locks won't be reclaimed. In the future, it would be nice to be able to notify userspace that locks have been lost (probably by implementing SIGLOST), and adding some good policies about how long we should reattempt to reclaim the locks. Finally, I removed a comment about memory leaks that I believe is obsolete and added a new one to clarify the result of sending a SIGKILL to the reclaimer thread. As best I can tell, doing so doesn't actually cause a memory leak. I consider this patch 2.6.29 material. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23LOCKD: Make lockd_up() and lockd_down() exported GPL-onlyTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-15Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/e1000e/ich8lan.c
2008-11-24NLM: client-side nlm_lookup_host() should avoid matching on srcaddrChuck Lever
Since commit c98451bd, the loop in nlm_lookup_host() unconditionally compares the host's h_srcaddr field to the incoming source address. For client-side nlm_host entries, both are always AF_UNSPEC, so this check is unnecessary. Since commit 781b61a6, which added support for AF_INET6 addresses to nlm_cmp_addr(), nlm_cmp_addr() now returns FALSE for AF_UNSPEC addresses, which causes nlm_lookup_host() to create a fresh nlm_host entry every time it is called on the client. These extra entries will eventually expire once the server is unmounted, so the impact of this regression, introduced with lockd IPv6 support in 2.6.28, should be minor. We could fix this by adding an arm in nlm_cmp_addr() for AF_UNSPEC addresses, but really, nlm_lookup_host() shouldn't be matching on the srcaddr field for client-side nlm_host lookups. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-11-24nfsd: clean up grace period on early exitJ. Bruce Fields
If nfsd was shut down before the grace period ended, we could end up with a freed object still on grace_list. Thanks to Jeff Moyer for reporting the resulting list corruption warnings. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Tested-by: Jeff Moyer <jmoyer@redhat.com>
2008-11-06Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/wireless/ath5k/base.c net/8021q/vlan_core.c
2008-10-31fs: replace NIPQUAD()Harvey Harrison
Using NIPQUAD() with NIPQUAD_FMT, %d.%d.%d.%d or %u.%u.%u.%u can be replaced with %pI4 Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-30NLM: Set address family before calling nlm_host_rebooted()Chuck Lever
The nlm_host_rebooted() function uses nlm_cmp_addr() to find an nsm_handle that matches the rebooted peer. In order for this to work, the passed-in address must have a proper address family. This fixes a post-2.6.28 regression introduced by commit 781b61a6, which added AF_INET6 support to nlm_cmp_addr(). Before that commit, nlm_cmp_addr() didn't care about the address family; it compared only the sin_addr.s_addr field for equality. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-10-29net: replace %p6 with %pI6Harvey Harrison
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-28misc: replace NIP6_FMT with %p6 format specifierHarvey Harrison
The iscsi_ibft.c changes are almost certainly a bugfix as the pointer 'ip' is a u8 *, so they never print the last 8 bytes of the IPv6 address, and the eight bytes they do print have a zero byte with them in each 16-bit word. Other than that, this should cause no difference in functionality. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-04NLM: Remove "proto" argument from lockd_up()Chuck Lever
Clean up: Now that lockd_up() starts listeners for both transports, the "proto" argument is no longer needed. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-10-04NLM: Always start both UDP and TCP listenersChuck Lever
Commit 24e36663, which first appeared in 2.6.19, changed lockd so that the client side starts a UDP listener only if there is a UDP NFSv2/v3 mount. Its description notes: This... means that lockd will *not* listen on UDP if the only mounts are TCP mount (and nfsd hasn't started). The latter is the only one that concerns me at all - I don't know if this might be a problem with some servers. Unfortunately it is a problem for Linux itself. The rpc.statd daemon on Linux uses UDP for contacting the local lockd, no matter which protocol is used for NFS mounts. Without a local lockd UDP listener, NFSv2/v3 lock recovery from Linux NFS clients always fails. Revert parts of commit 24e36663 so lockd_up() always starts both listeners. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-10-03lockd: Remove unused fields in the nlm_reboot structureChuck Lever
The nlm_reboot structure is used to store information provided by the NSM_NOTIFY procedure. This procedure is not specified by the NLM or NSM protocols, other than to say that the procedure can be used to transmit information private to a particular NLM/NSM implementation. For Linux, the callback arguments include the name of the monitored host, the new NSM state of the host, and a 16-byte private opaque. As a clean up, remove the unused fields and the server-side XDR logic that decodes them. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-10-03lockd: Add helper to sanity check incoming NOTIFY requestsChuck Lever
lockd accepts SM_NOTIFY calls only from a privileged process on the local system. If lockd uses an AF_INET6 listener, the sender's address (ie the local rpc.statd) will be the IPv6 loopback address, not the IPv4 loopback address. Make sure the privilege test in nlmsvc_proc_sm_notify() and nlm4svc_proc_sm_notify() works for both AF_INET and AF_INET6 family addresses by refactoring the test into a helper and adding support for IPv6 addresses. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-10-03lockd: change nlmclnt_grant() to take a "struct sockaddr *"Chuck Lever
Adjust the signature and callers of nlmclnt_grant() to pass a "struct sockaddr *" instead of a "struct sockaddr_in *" in order to support IPv6 addresses. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-10-03lockd: Adjust nlmsvc_lookup_host() to accomodate AF_INET6 addressesChuck Lever
Fix up nlmsvc_lookup_host() to pass AF_INET6 source addresses to nlm_lookup_host(). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-10-03lockd: Adjust nlmclnt_lookup_host() signature to accomodate non-AF_INETChuck Lever
Pass a struct sockaddr * and a length to nlmclnt_lookup_host() to accomodate non-AF_INET family addresses. As a side benefit, eliminate the hostname_len argument, as the hostname is always NUL-terminated. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-10-03lockd: Support non-AF_INET addresses in nlm_lookup_host()Chuck Lever
Use struct sockaddr * and length in nlm_lookup_host_info to all callers to pass in either AF_INET or AF_INET6 addresses. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-10-03NLM: Convert nlm_lookup_host() to use a single argumentChuck Lever
The nlm_lookup_host() function already has a large number of arguments, and I'm about to add a few more. As a clean up, convert the function to use a single data structure argument. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-10-03lockd: reject reclaims outside the grace periodJ. Bruce Fields
The current lockd does not reject reclaims that arrive outside of the grace period. Accepting a reclaim means promising to the client that no conflicting locks were granted since last it held the lock. We can meet that promise if we assume the only lockers are nfs clients, and that they are sufficiently well-behaved to reclaim only locks that they held before, and that only reclaim locks have been permitted so far. Once we leave the grace period (and start permitting non-reclaims), we can no longer keep that promise. So we must start rejecting reclaims at that point. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-10-03lockd: move grace period checks to common codeJ. Bruce Fields
Do all the grace period checks in svclock.c. This simplifies the code a bit, and will ease some later changes. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-10-03nfsd: common grace period controlJ. Bruce Fields
Rewrite grace period code to unify management of grace period across lockd and nfsd. The current code has lockd and nfsd cooperate to compute a grace period which is satisfactory to them both, and then individually enforce it. This creates a slight race condition, since the enforcement is not coordinated. It's also more complicated than necessary. Here instead we have lockd and nfsd each inform common code when they enter the grace period, and when they're ready to leave the grace period, and allow normal locking only after both of them are ready to leave. We also expect the locks_start_grace()/locks_end_grace() interface here to be simpler to build on for future cluster/high-availability work, which may require (for example) putting individual filesystems into grace, or enforcing grace periods across multiple cluster nodes. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29lockd: Update nsm_find() to support non-AF_INET addressesChuck Lever
Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29lockd: Combine __nsm_find() and nsm_find().Chuck Lever
Clean up: Having two separate functions doesn't add clarity, so eliminate one of them. Use contemporary kernel coding conventions where appropriate. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29lockd: Support AF_INET6 when hashing addresses in nlm_lookup_hostChuck Lever
Adopt an approach similar to the RPC server's auth cache (from Aurelien Charbon and Brian Haley). Note nlm_lookup_host()'s existing IP address hash function has the same issue with correctness on little-endian systems as the original IPv4 auth cache hash function, so I've also updated it with a hash function similar to the new auth cache hash function. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29lockd: Teach nlm_cmp_addr() to support AF_INET6 addressesChuck Lever
Update the nlm_cmp_addr() helper to support AF_INET6 as well as AF_INET addresses. New version takes two "struct sockaddr *" arguments instead of "struct sockaddr_in *" arguments. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29NSM: Use sockaddr_storage for sm_addr fieldChuck Lever
To store larger addresses in the nsm_handle structure, make sm_addr a sockaddr_storage. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29lockd: Use sockaddr_storage for h_saddr fieldChuck Lever
To store larger addresses in the nlm_host structure, make h_saddr a sockaddr_storage. And let's call it something more self-explanatory: "saddr" could easily be mistaken for "server address". Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29lockd: Use sockaddr_storage + length for h_addr fieldChuck Lever
To store larger addresses in the nlm_host structure, make h_addr a sockaddr_storage, and add an address length field. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29lockd: Add address family-agnostic helper for zeroing the port numberChuck Lever
Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29lockd: Specify address family for source addressChuck Lever
Make sure an address family is specified for source addresses passed to nlm_lookup_host(). nlm_lookup_host() will need this when it becomes capable of dealing with AF_INET6 addresses. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29lockd: address-family independent printable addressesChuck Lever
Knowing which source address is used for communicating with remote NLM services can be helpful for debugging configuration problems on hosts with multiple addresses. Keep the dprintk debugging here, but adapt it so it displays AF_INET6 addresses properly. There are also a couple of dprintk clean-ups as well. At some point we will aggregate the helpers that display presentation format addresses into a single set of shared helpers. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29NLM: Clean up before introducing new debugging messagesChuck Lever
We're about to introduce some extra debugging messages in nlm_lookup_host(). Bring the coding style up to date first so we can cleanly introduce the new debugging messages. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29lockd: don't depend on lockd main loop to end graceJ. Bruce Fields
End lockd's grace period using schedule_delayed_work() instead of a check on every pass through the main loop. After a later patch, we'll depend on lockd to end its grace period even if it's not currently handling requests; so it shouldn't depend on being woken up from the main loop to do so. Also, Nakano Hiroaki (who independently produced a similar patch) noticed that the current behavior is buggy in the face of jiffies wraparound: "lockd uses time_before() to determine whether the grace period has expired. This would seem to be enough to avoid timer wrap-around issues, but, unfortunately, that is not the case. The time_* family of comparison functions can be safely used to compare jiffies relatively close in time, but they stop working after approximately LONG_MAX/2 ticks. nfsd can suffer this problem because the time_before() comparison in lockd() is not performed until the first request comes in, which means that if there is no lockd traffic for more than LONG_MAX/2 ticks we are screwed. "The implication of this is that once time_before() starts misbehaving any attempt from a NFS client to execute fcntl() will be received with a NLM_LCK_DENIED_GRACE_PERIOD message for 25 days (assuming HZ=1000). In other words, the 50 seconds grace period could turn into a grace period of 50 days or more. "Note: This bug was analyzed independently by Oda-san <oda@valinux.co.jp> and myself." Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Cc: Nakano Hiroaki <nakano.hiroaki@oss.ntt.co.jp> Cc: Itsuro Oda <oda@valinux.co.jp>