gfs2: make gfs2_ail1_empty_one return the count of active items

This patch is one baby step toward simplifying the journal management.
It simply changes function gfs2_ail1_empty_one from a void to an int and
makes it return a count of active items. This allows the caller to check
the return code rather than list_empty on the tr_ail1_list. This way
we can, in a later patch, combine transaction ail1 and ail2 lists.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/log.c

@@ -244,13 +244,15 @@ static void gfs2_ail1_start(struct gfs2_sbd *sdp)
  * @tr: the transaction
  * @max_revokes: If nonzero, issue revokes for the bd items for written buffers
  *
+ * returns: the transaction's count of remaining active items
  */
 
-static void gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
+static int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
 				int *max_revokes)
 {
 	struct gfs2_bufdata *bd, *s;
 	struct buffer_head *bh;
+	int active_count = 0;
 
 	list_for_each_entry_safe_reverse(bd, s, &tr->tr_ail1_list,
 					 bd_ail_st_list) {
@@ -265,8 +267,10 @@ static void gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
 		 * If the ail buffer is not busy and caught an error, flag it
 		 * for others.
 		 */
-		if (!sdp->sd_log_error && buffer_busy(bh))
+		if (!sdp->sd_log_error && buffer_busy(bh)) {
+			active_count++;
 			continue;
+		}
 		if (!buffer_uptodate(bh) &&
 		    !cmpxchg(&sdp->sd_log_error, 0, -EIO)) {
 			gfs2_io_error_bh(sdp, bh);
@@ -285,6 +289,7 @@ static void gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
 		}
 		list_move(&bd->bd_ail_st_list, &tr->tr_ail2_list);
 	}
+	return active_count;
 }
 
 /**
@@ -303,8 +308,7 @@ static int gfs2_ail1_empty(struct gfs2_sbd *sdp, int max_revokes)
 
 	spin_lock(&sdp->sd_ail_lock);
 	list_for_each_entry_safe_reverse(tr, s, &sdp->sd_ail1_list, tr_list) {
-		gfs2_ail1_empty_one(sdp, tr, &max_revokes);
-		if (list_empty(&tr->tr_ail1_list) && oldest_tr)
+		if (!gfs2_ail1_empty_one(sdp, tr, &max_revokes) && oldest_tr)
 			list_move(&tr->tr_list, &sdp->sd_ail2_list);
 		else
 			oldest_tr = 0;