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authorJeff Layton <jlayton@redhat.com>2008-12-23 15:21:33 -0500
committerTrond Myklebust <Trond.Myklebust@netapp.com>2008-12-23 15:21:33 -0500
commitdf94f000c46c055cf439f5b92807cd827557ffbc (patch)
treec3b224d3ae7c07a5edc3fc804a6d91c8cbdd5cc1
parent2de59872a7842143f4507832e7c1f5123c47feb7 (diff)
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lockd: convert reclaimer thread to kthread interface
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 Finally, I removed a comment about memory leaks that I believe is obsolete and added a new one to clarify the result of sending a SIGKILL to the reclaimer thread.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>
-rw-r--r--fs/lockd/clntlock.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
index 8307dd64bf46..94d42cc4e393 100644
--- a/fs/lockd/clntlock.c
+++ b/fs/lockd/clntlock.c
@@ -14,6 +14,7 @@
#include <linux/sunrpc/svc.h>
#include <linux/lockd/lockd.h>
#include <linux/smp_lock.h>
+#include <linux/kthread.h>
#define NLMDBG_FACILITY NLMDBG_CLIENT
@@ -191,11 +192,15 @@ __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
void
nlmclnt_recovery(struct nlm_host *host)
{
+ struct task_struct *task;
+
if (!host->h_reclaiming++) {
nlm_get_host(host);
- __module_get(THIS_MODULE);
- if (kernel_thread(reclaimer, host, CLONE_FS | CLONE_FILES) < 0)
- module_put(THIS_MODULE);
+ task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name);
+ if (IS_ERR(task))
+ printk(KERN_ERR "lockd: unable to spawn reclaimer "
+ "thread. Locks for %s won't be reclaimed! "
+ "(%ld)\n", host->h_name, PTR_ERR(task));
}
}
@@ -207,7 +212,6 @@ reclaimer(void *ptr)
struct file_lock *fl, *next;
u32 nsmstate;
- daemonize("%s-reclaim", host->h_name);
allow_signal(SIGKILL);
down_write(&host->h_rwsem);
@@ -233,7 +237,12 @@ restart:
list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
list_del_init(&fl->fl_u.nfs_fl.list);
- /* Why are we leaking memory here? --okir */
+ /*
+ * sending this thread a SIGKILL will result in any unreclaimed
+ * locks being removed from the h_granted list. This means that
+ * the kernel will not attempt to reclaim them again if a new
+ * reclaimer thread is spawned for this host.
+ */
if (signalled())
continue;
if (nlmclnt_reclaim(host, fl) != 0)
@@ -261,5 +270,5 @@ restart:
nlm_release_host(host);
lockd_down();
unlock_kernel();
- module_put_and_exit(0);
+ return 0;
}