xfs: some iget tracing cleanups / fixes

The xfs_iget_alloc/found tracepoints are a bit misnamed and misplaced.
Rename them to xfs_iget_hit/xfs_iget_miss and move them to the beggining
of the xfs_iget_cache_hit/miss functions.  Add a new xfs_iget_reclaim_fail
tracepoint for the case where we fail to re-initialize a VFS inode,
and add a second instance of the xfs_iget_skip tracepoint for the case
of a failed igrab() call.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

diff --git a/fs/xfs/linux-2.6/xfs_trace.h b/fs/xfs/linux-2.6/xfs_trace.h
index 3f2eec2..9efe368 100644
--- a/fs/xfs/linux-2.6/xfs_trace.h
+++ b/fs/xfs/linux-2.6/xfs_trace.h
@@ -561,8 +561,9 @@
 	TP_ARGS(ip))
 DEFINE_IGET_EVENT(xfs_iget_skip);
 DEFINE_IGET_EVENT(xfs_iget_reclaim);
-DEFINE_IGET_EVENT(xfs_iget_found);
-DEFINE_IGET_EVENT(xfs_iget_alloc);
+DEFINE_IGET_EVENT(xfs_iget_reclaim_fail);
+DEFINE_IGET_EVENT(xfs_iget_hit);
+DEFINE_IGET_EVENT(xfs_iget_miss);
 
 DECLARE_EVENT_CLASS(xfs_inode_class,
 	TP_PROTO(struct xfs_inode *ip, unsigned long caller_ip),