[PATCH v15 13/22] xfs: Add state machine tracepoints

[Allison Henderson <allison.henderson@xxxxxxxxxx>]

This is a quick patch to add a new tracepoint: xfs_das_state_return.  We
use this to track when ever a new state is set or -EAGAIN is returned

Signed-off-by: Allison Henderson <allison.henderson@xxxxxxxxxx>
---
 fs/xfs/libxfs/xfs_attr.c        | 31 ++++++++++++++++++++++++++++++-
 fs/xfs/libxfs/xfs_attr_remote.c |  1 +
 fs/xfs/xfs_trace.h              | 25 +++++++++++++++++++++++++
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index c7b86d5..ba21475 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -313,6 +313,7 @@ xfs_attr_set_fmt(
 	 * the attr fork to leaf format and will restart with the leaf
 	 * add.
 	 */
+	trace_xfs_attr_set_fmt_return(XFS_DAS_UNINIT, args->dp);
 	dac->flags |= XFS_DAC_DEFER_FINISH;
 	return -EAGAIN;
 }
@@ -378,6 +379,8 @@ 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)
@@ -400,10 +403,13 @@ xfs_attr_set_iter(
 				return error;
 
 			dac->dela_state = XFS_DAS_FOUND_NBLK;
+			trace_xfs_attr_set_iter_return(dac->dela_state,
+						       args->dp);
 			return -EAGAIN;
 		}
 
 		dac->dela_state = XFS_DAS_FOUND_LBLK;
+		trace_xfs_attr_set_iter_return(dac->dela_state, args->dp);
 		return -EAGAIN;
 
         case XFS_DAS_FOUND_LBLK:
@@ -433,6 +439,8 @@ xfs_attr_set_iter(
 			if (error)
 				return error;
 
+			trace_xfs_attr_set_iter_return(dac->dela_state,
+						       args->dp);
 			return -EAGAIN;
 		}
 
@@ -469,6 +477,7 @@ 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:
 		/*
@@ -488,6 +497,9 @@ xfs_attr_set_iter(
 	case 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;
 		}
@@ -545,6 +557,8 @@ xfs_attr_set_iter(
 				if (error)
 					return error;
 
+				trace_xfs_attr_set_iter_return(
+					dac->dela_state, args->dp);
 				return -EAGAIN;
 			}
 
@@ -581,6 +595,7 @@ 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:
@@ -601,6 +616,10 @@ xfs_attr_set_iter(
 	case 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;
 		}
@@ -1214,6 +1233,8 @@ 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;
 		}
 
@@ -1394,6 +1415,9 @@ xfs_attr_node_remove_rmt (
 	 * May return -EAGAIN to request that the caller recall this function
 	 */
 	error = __xfs_attr_rmtval_remove(dac);
+	if (error == -EAGAIN)
+		trace_xfs_attr_node_remove_rmt_return(dac->dela_state,
+						      dac->da_args->dp);
 	if (error)
 		return error;
 
@@ -1513,6 +1537,8 @@ xfs_attr_node_removename_iter(
 
 			dac->flags |= XFS_DAC_DEFER_FINISH;
 			dac->dela_state = XFS_DAS_RM_SHRINK;
+			trace_xfs_attr_node_removename_iter_return(
+					dac->dela_state, args->dp);
 			return -EAGAIN;
 		}
 
@@ -1531,8 +1557,11 @@ xfs_attr_node_removename_iter(
 		goto out;
 	}
 
-	if (error == -EAGAIN)
+	if (error == -EAGAIN) {
+		trace_xfs_attr_node_removename_iter_return(
+					dac->dela_state, args->dp);
 		return error;
+	}
 out:
 	if (state)
 		xfs_da_state_free(state);
diff --git a/fs/xfs/libxfs/xfs_attr_remote.c b/fs/xfs/libxfs/xfs_attr_remote.c
index 6af86bf..b242e1a 100644
--- a/fs/xfs/libxfs/xfs_attr_remote.c
+++ b/fs/xfs/libxfs/xfs_attr_remote.c
@@ -763,6 +763,7 @@ __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;
 	}
 
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 363e1bf..7993f55 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -3927,6 +3927,31 @@ DEFINE_EVENT(xfs_eofblocks_class, name,	\
 DEFINE_EOFBLOCKS_EVENT(xfs_ioc_free_eofblocks);
 DEFINE_EOFBLOCKS_EVENT(xfs_blockgc_free_space);
 
+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_set_fmt_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_node_removename_iter_return);
+DEFINE_DAS_STATE_EVENT(xfs_attr_node_remove_rmt_return);
+DEFINE_DAS_STATE_EVENT(xfs_attr_rmtval_remove_return);
 #endif /* _TRACE_XFS_H */
 
 #undef TRACE_INCLUDE_PATH
-- 
2.7.4