dlm for 3.8

This set fixes some conditions in which value blocks are invalidated,
 and includes two trivial cleanups.
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Merge tag 'dlm-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm

Pull dlm updates from David Teigland:
 "This set fixes some conditions in which value blocks are invalidated,
  and includes two trivial cleanups."

* tag 'dlm-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
  dlm: fix lvb invalidation conditions
  fs/dlm: remove CONFIG_EXPERIMENTAL
  dlm: remove unused variable in *dlm_lowcomms_get_buffer()

fs/dlm/Kconfig

@@ -1,6 +1,6 @@
 menuconfig DLM
 	tristate "Distributed Lock Manager (DLM)"
-	depends on EXPERIMENTAL && INET
+	depends on INET
 	depends on SYSFS && CONFIGFS_FS && (IPV6 || IPV6=n)
 	select IP_SCTP
 	help

fs/dlm/dlm_internal.h

@@ -337,6 +337,7 @@ enum rsb_flags {
 	RSB_NEW_MASTER2,
 	RSB_RECOVER_CONVERT,
 	RSB_RECOVER_GRANT,
+	RSB_RECOVER_LVB_INVAL,
 };
 
 static inline void rsb_set_flag(struct dlm_rsb *r, enum rsb_flags flag)

fs/dlm/lock.c

@@ -5393,6 +5393,13 @@ static void purge_dead_list(struct dlm_ls *ls, struct dlm_rsb *r,
 		if ((lkb->lkb_nodeid == nodeid_gone) ||
 		    dlm_is_removed(ls, lkb->lkb_nodeid)) {
 
+			/* tell recover_lvb to invalidate the lvb
+			   because a node holding EX/PW failed */
+			if ((lkb->lkb_exflags & DLM_LKF_VALBLK) &&
+			    (lkb->lkb_grmode >= DLM_LOCK_PW)) {
+				rsb_set_flag(r, RSB_RECOVER_LVB_INVAL);
+			}
+
 			del_lkb(r, lkb);
 
 			/* this put should free the lkb */
@@ -6025,15 +6032,18 @@ static int orphan_proc_lock(struct dlm_ls *ls, struct dlm_lkb *lkb)
 	return error;
 }
 
-/* The force flag allows the unlock to go ahead even if the lkb isn't granted.
-   Regardless of what rsb queue the lock is on, it's removed and freed. */
+/* The FORCEUNLOCK flag allows the unlock to go ahead even if the lkb isn't
+   granted.  Regardless of what rsb queue the lock is on, it's removed and
+   freed.  The IVVALBLK flag causes the lvb on the resource to be invalidated
+   if our lock is PW/EX (it's ignored if our granted mode is smaller.) */
 
 static int unlock_proc_lock(struct dlm_ls *ls, struct dlm_lkb *lkb)
 {
 	struct dlm_args args;
 	int error;
 
-	set_unlock_args(DLM_LKF_FORCEUNLOCK, lkb->lkb_ua, &args);
+	set_unlock_args(DLM_LKF_FORCEUNLOCK | DLM_LKF_IVVALBLK,
+			lkb->lkb_ua, &args);
 
 	error = unlock_lock(ls, lkb, &args);
 	if (error == -DLM_EUNLOCK)

fs/dlm/lowcomms.c

@@ -1385,7 +1385,6 @@ void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
 	struct connection *con;
 	struct writequeue_entry *e;
 	int offset = 0;
-	int users = 0;
 
 	con = nodeid2con(nodeid, allocation);
 	if (!con)
@@ -1399,7 +1398,7 @@ void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
 	} else {
 		offset = e->end;
 		e->end += len;
-		users = e->users++;
+		e->users++;
 	}
 	spin_unlock(&con->writequeue_lock);
 
@@ -1414,7 +1413,7 @@ void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
 		spin_lock(&con->writequeue_lock);
 		offset = e->end;
 		e->end += len;
-		users = e->users++;
+		e->users++;
 		list_add_tail(&e->list, &con->writequeue);
 		spin_unlock(&con->writequeue_lock);
 		goto got_one;

fs/dlm/recover.c

@@ -717,8 +717,14 @@ void dlm_recovered_lock(struct dlm_rsb *r)
  * the VALNOTVALID flag if necessary, and determining the correct lvb contents
  * based on the lvb's of the locks held on the rsb.
  *
- * RSB_VALNOTVALID is set if there are only NL/CR locks on the rsb.  If it
- * was already set prior to recovery, it's not cleared, regardless of locks.
+ * RSB_VALNOTVALID is set in two cases:
+ *
+ * 1. we are master, but not new, and we purged an EX/PW lock held by a
+ * failed node (in dlm_recover_purge which set RSB_RECOVER_LVB_INVAL)
+ *
+ * 2. we are a new master, and there are only NL/CR locks left.
+ * (We could probably improve this by only invaliding in this way when
+ * the previous master left uncleanly.  VMS docs mention that.)
  *
  * The LVB contents are only considered for changing when this is a new master
  * of the rsb (NEW_MASTER2).  Then, the rsb's lvb is taken from any lkb with
@@ -734,6 +740,19 @@ static void recover_lvb(struct dlm_rsb *r)
 	int big_lock_exists = 0;
 	int lvblen = r->res_ls->ls_lvblen;
 
+	if (!rsb_flag(r, RSB_NEW_MASTER2) &&
+	    rsb_flag(r, RSB_RECOVER_LVB_INVAL)) {
+		/* case 1 above */
+		rsb_set_flag(r, RSB_VALNOTVALID);
+		return;
+	}
+
+	if (!rsb_flag(r, RSB_NEW_MASTER2))
+		return;
+
+	/* we are the new master, so figure out if VALNOTVALID should
+	   be set, and set the rsb lvb from the best lkb available. */
+
 	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
 		if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
 			continue;
@@ -772,13 +791,10 @@ static void recover_lvb(struct dlm_rsb *r)
 	if (!lock_lvb_exists)
 		goto out;
 
+	/* lvb is invalidated if only NL/CR locks remain */
 	if (!big_lock_exists)
 		rsb_set_flag(r, RSB_VALNOTVALID);
 
-	/* don't mess with the lvb unless we're the new master */
-	if (!rsb_flag(r, RSB_NEW_MASTER2))
-		goto out;
-
 	if (!r->res_lvbptr) {
 		r->res_lvbptr = dlm_allocate_lvb(r->res_ls);
 		if (!r->res_lvbptr)
@@ -852,12 +868,19 @@ void dlm_recover_rsbs(struct dlm_ls *ls)
 		if (is_master(r)) {
 			if (rsb_flag(r, RSB_RECOVER_CONVERT))
 				recover_conversion(r);
+
+			/* recover lvb before granting locks so the updated
+			   lvb/VALNOTVALID is presented in the completion */
+			recover_lvb(r);
+
 			if (rsb_flag(r, RSB_NEW_MASTER2))
 				recover_grant(r);
-			recover_lvb(r);
 			count++;
+		} else {
+			rsb_clear_flag(r, RSB_VALNOTVALID);
 		}
 		rsb_clear_flag(r, RSB_RECOVER_CONVERT);
+		rsb_clear_flag(r, RSB_RECOVER_LVB_INVAL);
 		rsb_clear_flag(r, RSB_NEW_MASTER2);
 		unlock_rsb(r);
 	}