JFS: Fix race waking up jfsIO kernel thread

It's possible for a journal I/O request to be added to the log_redrive
queue and the jfsIO thread to be awakened after the thread releases
log_redrive_lock but before it sets its state to TASK_INTERRUPTIBLE.

The jfsIO thread should set the state before giving up the spinlock, so
the waking thread will really wake it.

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>

diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index ff7f1be..16c6268 100644 (file)
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -2354,12 +2354,13 @@ int jfsIOWait(void *arg)
                        lbmStartIO(bp);
                        spin_lock_irq(&log_redrive_lock);
                }
-               spin_unlock_irq(&log_redrive_lock);
 
                if (freezing(current)) {
+                       spin_unlock_irq(&log_redrive_lock);
                        refrigerator();
                } else {
                        set_current_state(TASK_INTERRUPTIBLE);
+                       spin_unlock_irq(&log_redrive_lock);
                        schedule();
                        __set_current_state(TASK_RUNNING);
                }