commit f0bd95ea72644cbf9210606f6f8edfce13d65d47
author Tsutomu Itoh <t-itoh@jp.fujitsu.com> Mon Oct 01 03:08:37 2012 -0600
committer Chris Mason <chris.mason@fusionio.com> Tue Oct 09 09:15:42 2012 -0400
tree 1d0c37da707984971f14f48966b40d5c86ea63ee
parent 18ec90d63f43cf785f6e73e7a7db546bff3fa380

Btrfs: confirmation of value is added before trace_btrfs_get_extent() is called

We should confirm the value of extent_map before calling
trace_btrfs_get_extent() because the value of extent_map has the
possibility of NULL.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>

fs/btrfs/inode.c

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d24b650..f92def2 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5505,7 +5505,8 @@
 	write_unlock(&em_tree->lock);
 out:
 
-	trace_btrfs_get_extent(root, em);
+	if (em)
+		trace_btrfs_get_extent(root, em);
 
 	if (path)
 		btrfs_free_path(path);