From 479c641273df632478cda7fe76b833df64e319bc Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Tue, 21 Jun 2016 11:53:28 +1000 Subject: [PATCH] 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 Reviewed-by: Christoph Hellwig Signed-off-by: Dave Chinner --- fs/xfs/xfs_buf.c | 8 +++++--- fs/xfs/xfs_trace.h | 1 + 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index e71cfbd5acb3..f14daebbc531 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -944,10 +944,12 @@ xfs_buf_trylock( int locked; locked = down_trylock(&bp->b_sema) == 0; - if (locked) + if (locked) { XB_SET_OWNER(bp); - - trace_xfs_buf_trylock(bp, _RET_IP_); + trace_xfs_buf_trylock(bp, _RET_IP_); + } else { + trace_xfs_buf_trylock_fail(bp, _RET_IP_); + } return locked; } diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index ea94ee0fe5ea..68f27f70e1ed 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -354,6 +354,7 @@ DEFINE_BUF_EVENT(xfs_buf_submit_wait); 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);