lockd: Fix Oopses due to list manipulation errors.

The patch "stop abusing file_lock_list introduces a couple of bugs since
the locks may be copied and need to be removed from the lists when they are
destroyed.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 15 insertions, 14 deletions

diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
index 0fc0ee267b04..7cf41c1e1a88 100644
--- a/fs/lockd/clntlock.c
+++ b/fs/lockd/clntlock.c
@@ -213,11 +213,12 @@ reclaimer(void *ptr)
         /* First, reclaim all locks that have been marked. */
 restart:
         list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
-                list_del(&fl->fl_u.nfs_fl.list);
+                list_del_init(&fl->fl_u.nfs_fl.list);
 
-                nlmclnt_reclaim(host, fl);
                 if (signalled())
-                        break;
+                        continue;
+                if (nlmclnt_reclaim(host, fl) == 0)
+                        list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
                 goto restart;
         }
 
diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index cb469431bd1d..3e90356b4882 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -446,12 +446,14 @@ nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 
 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 {
-        memcpy(&new->fl_u.nfs_fl, &fl->fl_u.nfs_fl, sizeof(new->fl_u.nfs_fl));
-        nlm_get_lockowner(new->fl_u.nfs_fl.owner);
+        new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
+        new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
+        list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 }
 
 static void nlmclnt_locks_release_private(struct file_lock *fl)
 {
+        list_del(&fl->fl_u.nfs_fl.list);
         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
         fl->fl_ops = NULL;
 }
@@ -466,6 +468,7 @@ static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *ho
         BUG_ON(fl->fl_ops != NULL);
         fl->fl_u.nfs_fl.state = 0;
         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
+        INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
         fl->fl_ops = &nlmclnt_lock_ops;
 }
 
@@ -552,7 +555,7 @@ nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
         if (resp->status == NLM_LCK_GRANTED) {
                 fl->fl_u.nfs_fl.state = host->h_state;
                 fl->fl_flags |= FL_SLEEP;
-                list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
+                /* Ensure the resulting lock will get added to granted list */
                 do_vfs_lock(fl);
         }
         status = nlm_stat_to_errno(resp->status);
@@ -619,12 +622,6 @@ nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
         int             status;
 
         /*
-         * Remove from the granted list now so the lock doesn't get
-         * reclaimed while we're stuck in the unlock call.
-         */
-        list_del(&fl->fl_u.nfs_fl.list);
-
-        /*
          * Note: the server is supposed to either grant us the unlock
          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
          * case, we want to unlock.
diff --git a/fs/lockd/host.c b/fs/lockd/host.c
index f456f8ed9acd..112ebf8b8dfe 100644
--- a/fs/lockd/host.c
+++ b/fs/lockd/host.c
@@ -245,8 +245,12 @@ void nlm_release_host(struct nlm_host *host)
 {
         if (host != NULL) {
                 dprintk("lockd: release host %s\n", host->h_name);
-                atomic_dec(&host->h_count);
                 BUG_ON(atomic_read(&host->h_count) < 0);
+                if (atomic_dec_and_test(&host->h_count)) {
+                        BUG_ON(!list_empty(&host->h_lockowners));
+                        BUG_ON(!list_empty(&host->h_granted));
+                        BUG_ON(!list_empty(&host->h_reclaim));
+                }
         }
 }
 
@@ -334,7 +338,6 @@ nlm_gc_hosts(void)
                                         rpc_destroy_client(host->h_rpcclnt);
                                 }
                         }
-                        BUG_ON(!list_empty(&host->h_lockowners));
                         kfree(host);
                         nrhosts--;
                 }