1 files changed, 8 insertions, 0 deletions

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index a1920da22802..10f524c59ea8 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -639,6 +639,7 @@ do_get_write_access(handle_t *handle, struct journal_head *jh,
         int error;
         char *frozen_buffer = NULL;
         int need_copy = 0;
+        unsigned long start_lock, time_lock;
 
         if (is_handle_aborted(handle))
                 return -EROFS;
@@ -654,9 +655,16 @@ repeat:
 
         /* @@@ Need to check for errors here at some point. */
 
+        start_lock = jiffies;
         lock_buffer(bh);
         jbd_lock_bh_state(bh);
 
+        /* If it takes too long to lock the buffer, trace it */
+        time_lock = jbd2_time_diff(start_lock, jiffies);
+        if (time_lock > HZ/10)
+                trace_jbd2_lock_buffer_stall(bh->b_bdev->bd_dev,
+                        jiffies_to_msecs(time_lock));
+
         /* We now hold the buffer lock so it is safe to query the buffer
          * state.  Is the buffer dirty?
          *