xfs: add attr state machine tracepoints

This is a quick patch to add a new xfs_attr_*_return tracepoints.  We
use these to track when ever a new state is set or -EAGAIN is returned
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

fs/xfs/libxfs/xfs_attr.c

@@ -335,6 +335,7 @@ xfs_attr_sf_addname(
 	 * the attr fork to leaf format and will restart with the leaf
 	 * add.
 	 */
+	trace_xfs_attr_sf_addname_return(XFS_DAS_UNINIT, args->dp);
 	dac->flags |= XFS_DAC_DEFER_FINISH;
 	return -EAGAIN;
 }
@@ -394,6 +395,8 @@ xfs_attr_set_iter(
 				 * handling code below
 				 */
 				dac->flags |= XFS_DAC_DEFER_FINISH;
+				trace_xfs_attr_set_iter_return(
+					dac->dela_state, args->dp);
 				return -EAGAIN;
 			} else if (error) {
 				return error;
@@ -411,6 +414,7 @@ xfs_attr_set_iter(
 
 			dac->dela_state = XFS_DAS_FOUND_NBLK;
 		}
+		trace_xfs_attr_set_iter_return(dac->dela_state,	args->dp);
 		return -EAGAIN;
 	case XFS_DAS_FOUND_LBLK:
 		/*
@@ -438,6 +442,8 @@ xfs_attr_set_iter(
 			error = xfs_attr_rmtval_set_blk(dac);
 			if (error)
 				return error;
+			trace_xfs_attr_set_iter_return(dac->dela_state,
+						       args->dp);
 			return -EAGAIN;
 		}
 
@@ -472,6 +478,7 @@ xfs_attr_set_iter(
 		 * series.
 		 */
 		dac->dela_state = XFS_DAS_FLIP_LFLAG;
+		trace_xfs_attr_set_iter_return(dac->dela_state, args->dp);
 		return -EAGAIN;
 	case XFS_DAS_FLIP_LFLAG:
 		/*
@@ -489,10 +496,14 @@ xfs_attr_set_iter(
 		dac->dela_state = XFS_DAS_RM_LBLK;
 		if (args->rmtblkno) {
 			error = __xfs_attr_rmtval_remove(dac);
+			if (error == -EAGAIN)
+				trace_xfs_attr_set_iter_return(
+					dac->dela_state, args->dp);
 			if (error)
 				return error;
 
 			dac->dela_state = XFS_DAS_RD_LEAF;
+			trace_xfs_attr_set_iter_return(dac->dela_state, args->dp);
 			return -EAGAIN;
 		}
 
@@ -542,6 +553,8 @@ xfs_attr_set_iter(
 				error = xfs_attr_rmtval_set_blk(dac);
 				if (error)
 					return error;
+				trace_xfs_attr_set_iter_return(
+					dac->dela_state, args->dp);
 				return -EAGAIN;
 			}
 
@@ -577,6 +590,7 @@ xfs_attr_set_iter(
 		 * series
 		 */
 		dac->dela_state = XFS_DAS_FLIP_NFLAG;
+		trace_xfs_attr_set_iter_return(dac->dela_state, args->dp);
 		return -EAGAIN;
 
 	case XFS_DAS_FLIP_NFLAG:
@@ -596,10 +610,15 @@ xfs_attr_set_iter(
 		dac->dela_state = XFS_DAS_RM_NBLK;
 		if (args->rmtblkno) {
 			error = __xfs_attr_rmtval_remove(dac);
+			if (error == -EAGAIN)
+				trace_xfs_attr_set_iter_return(
+					dac->dela_state, args->dp);
+
 			if (error)
 				return error;
 
 			dac->dela_state = XFS_DAS_CLR_FLAG;
+			trace_xfs_attr_set_iter_return(dac->dela_state, args->dp);
 			return -EAGAIN;
 		}
 
@@ -1176,6 +1195,8 @@ xfs_attr_node_addname(
 			 * this point.
 			 */
 			dac->flags |= XFS_DAC_DEFER_FINISH;
+			trace_xfs_attr_node_addname_return(
+					dac->dela_state, args->dp);
 			return -EAGAIN;
 		}
 
@@ -1422,10 +1443,13 @@ xfs_attr_remove_iter(
 			 * blocks are removed.
 			 */
 			error = __xfs_attr_rmtval_remove(dac);
-			if (error == -EAGAIN)
+			if (error == -EAGAIN) {
+				trace_xfs_attr_remove_iter_return(
+						dac->dela_state, args->dp);
 				return error;
-			else if (error)
+			} else if (error) {
 				goto out;
+			}
 
 			/*
 			 * Refill the state structure with buffers (the prior
@@ -1438,6 +1462,7 @@ xfs_attr_remove_iter(
 				goto out;
 			dac->dela_state = XFS_DAS_RM_NAME;
 			dac->flags |= XFS_DAC_DEFER_FINISH;
+			trace_xfs_attr_remove_iter_return(dac->dela_state, args->dp);
 			return -EAGAIN;
 		}
 
@@ -1466,6 +1491,8 @@ xfs_attr_remove_iter(
 
 			dac->flags |= XFS_DAC_DEFER_FINISH;
 			dac->dela_state = XFS_DAS_RM_SHRINK;
+			trace_xfs_attr_remove_iter_return(
+					dac->dela_state, args->dp);
 			return -EAGAIN;
 		}
 

fs/xfs/libxfs/xfs_attr_remote.c

@@ -696,6 +696,7 @@ __xfs_attr_rmtval_remove(
 	 */
 	if (!done) {
 		dac->flags |= XFS_DAC_DEFER_FINISH;
+		trace_xfs_attr_rmtval_remove_return(dac->dela_state, args->dp);
 		return -EAGAIN;
 	}
 

fs/xfs/xfs_trace.h

@@ -4073,6 +4073,30 @@ DEFINE_ICLOG_EVENT(xlog_iclog_want_sync);
 DEFINE_ICLOG_EVENT(xlog_iclog_wait_on);
 DEFINE_ICLOG_EVENT(xlog_iclog_write);
 
+DECLARE_EVENT_CLASS(xfs_das_state_class,
+	TP_PROTO(int das, struct xfs_inode *ip),
+	TP_ARGS(das, ip),
+	TP_STRUCT__entry(
+		__field(int, das)
+		__field(xfs_ino_t, ino)
+	),
+	TP_fast_assign(
+		__entry->das = das;
+		__entry->ino = ip->i_ino;
+	),
+	TP_printk("state change %d ino 0x%llx",
+		  __entry->das, __entry->ino)
+)
+
+#define DEFINE_DAS_STATE_EVENT(name) \
+DEFINE_EVENT(xfs_das_state_class, name, \
+	TP_PROTO(int das, struct xfs_inode *ip), \
+	TP_ARGS(das, ip))
+DEFINE_DAS_STATE_EVENT(xfs_attr_sf_addname_return);
+DEFINE_DAS_STATE_EVENT(xfs_attr_set_iter_return);
+DEFINE_DAS_STATE_EVENT(xfs_attr_node_addname_return);
+DEFINE_DAS_STATE_EVENT(xfs_attr_remove_iter_return);
+DEFINE_DAS_STATE_EVENT(xfs_attr_rmtval_remove_return);
 #endif /* _TRACE_XFS_H */
 
 #undef TRACE_INCLUDE_PATH