1 files changed, 34 insertions, 10 deletions

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index d6edf8d14f9c..71034f41a2ba 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -97,6 +97,7 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
                    "BdiDirtyThresh:     %10lu kB\n"
                    "DirtyThresh:        %10lu kB\n"
                    "BackgroundThresh:   %10lu kB\n"
+                   "BdiDirtied:         %10lu kB\n"
                    "BdiWritten:         %10lu kB\n"
                    "BdiWriteBandwidth:  %10lu kBps\n"
                    "b_dirty:            %10lu\n"
@@ -109,6 +110,7 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
                    K(bdi_thresh),
                    K(dirty_thresh),
                    K(background_thresh),
+                   (unsigned long) K(bdi_stat(bdi, BDI_DIRTIED)),
                    (unsigned long) K(bdi_stat(bdi, BDI_WRITTEN)),
                    (unsigned long) K(bdi->write_bandwidth),
                    nr_dirty,
@@ -359,6 +361,17 @@ static unsigned long bdi_longest_inactive(void)
         return max(5UL * 60 * HZ, interval);
 }
 
+/*
+ * Clear pending bit and wakeup anybody waiting for flusher thread creation or
+ * shutdown
+ */
+static void bdi_clear_pending(struct backing_dev_info *bdi)
+{
+        clear_bit(BDI_pending, &bdi->state);
+        smp_mb__after_clear_bit();
+        wake_up_bit(&bdi->state, BDI_pending);
+}
+
 static int bdi_forker_thread(void *ptr)
 {
         struct bdi_writeback *me = ptr;
@@ -390,6 +403,12 @@ static int bdi_forker_thread(void *ptr)
                 }
 
                 spin_lock_bh(&bdi_lock);
+                /*
+                 * In the following loop we are going to check whether we have
+                 * some work to do without any synchronization with tasks
+                 * waking us up to do work for them. Set the task state here
+                 * so that we don't miss wakeups after verifying conditions.
+                 */
                 set_current_state(TASK_INTERRUPTIBLE);
 
                 list_for_each_entry(bdi, &bdi_list, bdi_list) {
@@ -456,7 +475,8 @@ static int bdi_forker_thread(void *ptr)
                                  * the bdi from the thread. Hopefully 1024 is
                                  * large enough for efficient IO.
                                  */
-                                writeback_inodes_wb(&bdi->wb, 1024);
+                                writeback_inodes_wb(&bdi->wb, 1024,
+                                                    WB_REASON_FORKER_THREAD);
                         } else {
                                 /*
                                  * The spinlock makes sure we do not lose
@@ -469,11 +489,13 @@ static int bdi_forker_thread(void *ptr)
                                 spin_unlock_bh(&bdi->wb_lock);
                                 wake_up_process(task);
                         }
+                        bdi_clear_pending(bdi);
                         break;
 
                 case KILL_THREAD:
                         __set_current_state(TASK_RUNNING);
                         kthread_stop(task);
+                        bdi_clear_pending(bdi);
                         break;
 
                 case NO_ACTION:
@@ -489,16 +511,8 @@ static int bdi_forker_thread(void *ptr)
                         else
                                 schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10));
                         try_to_freeze();
-                        /* Back to the main loop */
-                        continue;
+                        break;
                 }
-
-                /*
-                 * Clear pending bit and wakeup anybody waiting to tear us down.
-                 */
-                clear_bit(BDI_pending, &bdi->state);
-                smp_mb__after_clear_bit();
-                wake_up_bit(&bdi->state, BDI_pending);
         }
 
         return 0;
@@ -672,6 +686,8 @@ int bdi_init(struct backing_dev_info *bdi)
         bdi->bw_time_stamp = jiffies;
         bdi->written_stamp = 0;
 
+        bdi->balanced_dirty_ratelimit = INIT_BW;
+        bdi->dirty_ratelimit = INIT_BW;
         bdi->write_bandwidth = INIT_BW;
         bdi->avg_write_bandwidth = INIT_BW;
 
@@ -708,6 +724,14 @@ void bdi_destroy(struct backing_dev_info *bdi)
 
         bdi_unregister(bdi);
 
+        /*
+         * If bdi_unregister() had already been called earlier, the
+         * wakeup_timer could still be armed because bdi_prune_sb()
+         * can race with the bdi_wakeup_thread_delayed() calls from
+         * __mark_inode_dirty().
+         */
+        del_timer_sync(&bdi->wb.wakeup_timer);
+
         for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
                 percpu_counter_destroy(&bdi->bdi_stat[i]);