xfs: enable buffer deadlock postmortem diagnosis via ftrace
Create a second buf_trylock tracepoint so that we can distinguish
between a successful and a failed trylock. With this piece, we can
use a script to look at the ftrace output to detect buffer deadlocks.
[dchinner: update to if/else as per hch's suggestion]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index ea94ee0..68f27f7 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -354,6 +354,7 @@
DEFINE_BUF_EVENT(xfs_buf_bawrite);
DEFINE_BUF_EVENT(xfs_buf_lock);
DEFINE_BUF_EVENT(xfs_buf_lock_done);
+DEFINE_BUF_EVENT(xfs_buf_trylock_fail);
DEFINE_BUF_EVENT(xfs_buf_trylock);
DEFINE_BUF_EVENT(xfs_buf_unlock);
DEFINE_BUF_EVENT(xfs_buf_iowait);