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From:   ira.weiny@intel.com
To:     Dan Williams <dan.j.williams@intel.com>, Jan Kara <jack@suse.cz>,
        "Theodore Ts'o" <tytso@mit.edu>, Jeff Layton <jlayton@kernel.org>,
        Dave Chinner <david@fromorbit.com>
Cc:     Ira Weiny <ira.weiny@intel.com>,
        Matthew Wilcox <willy@infradead.org>,
        linux-xfs@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        John Hubbard <jhubbard@nvidia.com>,
        =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= <jglisse@redhat.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-nvdimm@lists.01.org, linux-ext4@vger.kernel.org,
        linux-mm@kvack.org
Subject: [PATCH RFC 01/10] fs/locks: Add trace_leases_conflict
Date:   Wed,  5 Jun 2019 18:45:34 -0700
Message-Id: <20190606014544.8339-2-ira.weiny@intel.com>
In-Reply-To: <20190606014544.8339-1-ira.weiny@intel.com>
References: <20190606014544.8339-1-ira.weiny@intel.com>
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From: Ira Weiny <ira.weiny@intel.com>

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
 fs/locks.c                      | 20 ++++++++++++++-----
 include/trace/events/filelock.h | 35 +++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 5 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index ec1e4a5df629..0cc2b9f30e22 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1534,11 +1534,21 @@ static void time_out_leases(struct inode *inode, struct list_head *dispose)
 
 static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
 {
-	if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
-		return false;
-	if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
-		return false;
-	return locks_conflict(breaker, lease);
+	bool rc;
+
+	if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT)) {
+		rc = false;
+		goto trace;
+	}
+	if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE)) {
+		rc = false;
+		goto trace;
+	}
+
+	rc = locks_conflict(breaker, lease);
+trace:
+	trace_leases_conflict(rc, lease, breaker);
+	return rc;
 }
 
 static bool
diff --git a/include/trace/events/filelock.h b/include/trace/events/filelock.h
index fad7befa612d..4b735923f2ff 100644
--- a/include/trace/events/filelock.h
+++ b/include/trace/events/filelock.h
@@ -203,6 +203,41 @@ TRACE_EVENT(generic_add_lease,
 		show_fl_type(__entry->fl_type))
 );
 
+TRACE_EVENT(leases_conflict,
+	TP_PROTO(bool conflict, struct file_lock *lease, struct file_lock *breaker),
+
+	TP_ARGS(conflict, lease, breaker),
+
+	TP_STRUCT__entry(
+		__field(void *, lease)
+		__field(void *, breaker)
+		__field(unsigned int, l_fl_flags)
+		__field(unsigned int, b_fl_flags)
+		__field(unsigned char, l_fl_type)
+		__field(unsigned char, b_fl_type)
+		__field(bool, conflict)
+	),
+
+	TP_fast_assign(
+		__entry->lease = lease;
+		__entry->l_fl_flags = lease->fl_flags;
+		__entry->l_fl_type = lease->fl_type;
+		__entry->breaker = breaker;
+		__entry->b_fl_flags = breaker->fl_flags;
+		__entry->b_fl_type = breaker->fl_type;
+		__entry->conflict = conflict;
+	),
+
+	TP_printk("conflict %d: lease=0x%p fl_flags=%s fl_type=%s; breaker=0x%p fl_flags=%s fl_type=%s",
+		__entry->conflict,
+		__entry->lease,
+		show_fl_flags(__entry->l_fl_flags),
+		show_fl_type(__entry->l_fl_type),
+		__entry->breaker,
+		show_fl_flags(__entry->b_fl_flags),
+		show_fl_type(__entry->b_fl_type))
+);
+
 #endif /* _TRACE_FILELOCK_H */
 
 /* This part must be outside protection */
-- 
2.20.1