---

yaml
---
r: 139616
b: refs/heads/master
c: d2caa3c
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 846c151a4de188bb8f7043097518dab2ff5b5c2c
+refs/heads/master: d2caa3c549c74d6476e2c29e13bd4d0e7d21c7fe

trunk/fs/fs-writeback.c

@@ -196,7 +196,7 @@ static void redirty_tail(struct inode *inode)
 		struct inode *tail_inode;
 
 		tail_inode = list_entry(sb->s_dirty.next, struct inode, i_list);
-		if (!time_after_eq(inode->dirtied_when,
+		if (time_before(inode->dirtied_when,
 				tail_inode->dirtied_when))
 			inode->dirtied_when = jiffies;
 	}
@@ -220,6 +220,21 @@ static void inode_sync_complete(struct inode *inode)
 	wake_up_bit(&inode->i_state, __I_SYNC);
 }
 
+static bool inode_dirtied_after(struct inode *inode, unsigned long t)
+{
+	bool ret = time_after(inode->dirtied_when, t);
+#ifndef CONFIG_64BIT
+	/*
+	 * For inodes being constantly redirtied, dirtied_when can get stuck.
+	 * It _appears_ to be in the future, but is actually in distant past.
+	 * This test is necessary to prevent such wrapped-around relative times
+	 * from permanently stopping the whole pdflush writeback.
+	 */
+	ret = ret && time_before_eq(inode->dirtied_when, jiffies);
+#endif
+	return ret;
+}
+
 /*
  * Move expired dirty inodes from @delaying_queue to @dispatch_queue.
  */
@@ -231,7 +246,7 @@ static void move_expired_inodes(struct list_head *delaying_queue,
 		struct inode *inode = list_entry(delaying_queue->prev,
 						struct inode, i_list);
 		if (older_than_this &&
-			time_after(inode->dirtied_when, *older_than_this))
+		    inode_dirtied_after(inode, *older_than_this))
 			break;
 		list_move(&inode->i_list, dispatch_queue);
 	}
@@ -492,8 +507,11 @@ void generic_sync_sb_inodes(struct super_block *sb,
 			continue;		/* blockdev has wrong queue */
 		}
 
-		/* Was this inode dirtied after sync_sb_inodes was called? */
-		if (time_after(inode->dirtied_when, start))
+		/*
+		 * Was this inode dirtied after sync_sb_inodes was called?
+		 * This keeps sync from extra jobs and livelock.
+		 */
+		if (inode_dirtied_after(inode, start))
 			break;
 
 		/* Is another pdflush already flushing this queue? */