Btrfs devel - Sep 2009 - [PATCH] Don't exist from cleaner_kthread and transaction_kthread until kthread_should_stop is true

upstream commit 2ad49887150894b9ed6a87a76b409adceee6b074

Motivated from the commit,
I found that cleaner_kthread() and transaction_kthread()
can result similar error since these two function can exit
even though kthread_should_stop() is not true.

In order to resolve the bug, break statements are changed
into continue statements in order to wait until kthread_should_stop()
becomes true.


--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c

--- a/fs/btrfs/disk-io.c   2009-08-17 06:19:38.000000000 +0900
+++ a/fs/btrfs/disk-io.c 2009-09-03 19:09:14.640625000 +0900
@@ -1435,7 +1435,7 @@
        do {
                smp_mb();
                if (root->fs_info->closing)
-                       break;
+                       continue;

                vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
                mutex_lock(&root->fs_info->cleaner_mutex);
@@ -1447,7 +1447,7 @@
                } else {
                        smp_mb();
                        if (root->fs_info->closing)
-                               break;
+                               continue;
                        set_current_state(TASK_INTERRUPTIBLE);
                        schedule();
                        __set_current_state(TASK_RUNNING);
@@ -1468,7 +1468,7 @@
        do {
                smp_mb();
                if (root->fs_info->closing)
-                       break;
+                       continue;

                delay = HZ * 30;
                vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
@@ -1499,7 +1499,7 @@
                        refrigerator();
                } else {
                        if (root->fs_info->closing)
-                               break;
+                               continue;
                        set_current_state(TASK_INTERRUPTIBLE);
                        schedule_timeout(delay);
                        __set_current_state(TASK_RUNNING);
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However, Vitaily Gusev notice me that kthread_stop() has been changed
recently so that it may executed for threads which was existed.
(commit  63706172f332fd3f6e7458ebfb35fa6de9c21dc5
              kthreads: rework kthread_stop())
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However, it seems that the kthread_stop() patch is not yet applied.
Linux 2.6.30.5 still use the order one.

On Fri, Sep 4, 2009 at 9:06 AM, 홍신 shin hong<hongshin@gmail.com>
wrote:
> However, Vitaily Gusev notice me that kthread_stop() has been changed
> recently so that it may executed for threads which was existed.
> (commit  63706172f332fd3f6e7458ebfb35fa6de9c21dc5
>              kthreads: rework kthread_stop())
>
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