[PATCH 2/3] xfs: add tracing to xfs_swap_extents

[Dave Chinner]

TO be able to diagnose whether the swap extents function is detecting
compatible inode data fork configurations for swapping extents, add
tracing points to the code to allow us to see the format of the
inode forks before and after the swap.

Signed-off-by: Dave Chinner <david at fromorbit.com>
---
 fs/xfs/linux-2.6/xfs_trace.h |   53 ++++++++++++++++++++++++++++++++++++++++++
 fs/xfs/xfs_dfrag.c           |    5 ++++
 2 files changed, 58 insertions(+), 0 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_trace.h b/fs/xfs/linux-2.6/xfs_trace.h
index 058fff1..1bb09e7 100644
--- a/fs/xfs/linux-2.6/xfs_trace.h
+++ b/fs/xfs/linux-2.6/xfs_trace.h
@@ -1441,6 +1441,59 @@ TRACE_EVENT(xfs_dir2_leafn_moveents,
 		  __entry->count)
 );
 
+#define XFS_SWAPEXT_INODES \
+	{ 0,	"target" }, \
+	{ 1,	"temp" }
+
+#define XFS_INODE_FORMAT_STR \
+	{ 0,	"invalid" }, \
+	{ 1,	"local" }, \
+	{ 2,	"extent" }, \
+	{ 3,	"btree" }
+
+DECLARE_EVENT_CLASS(xfs_swap_extent_class,
+	TP_PROTO(struct xfs_inode *ip, int which),
+	TP_ARGS(ip, which),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(int, which)
+		__field(xfs_ino_t, ino)
+		__field(int, format)
+		__field(int, nex)
+		__field(int, max_nex)
+		__field(int, broot_size)
+		__field(int, fork_off)
+	),
+	TP_fast_assign(
+		__entry->dev = VFS_I(ip)->i_sb->s_dev;
+		__entry->which = which;
+		__entry->ino = ip->i_ino;
+		__entry->format = ip->i_d.di_format;
+		__entry->nex = ip->i_d.di_nextents;
+		__entry->max_nex = ip->i_df.if_ext_max;
+		__entry->broot_size = ip->i_df.if_broot_bytes;
+		__entry->fork_off = XFS_IFORK_BOFF(ip);
+	),
+	TP_printk("dev %d:%d ino 0x%llx (%s), %s format, num_extents %d, "
+		  "Max in-fork extents %d, broot size %d, fork offset %d",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->ino,
+		  __print_symbolic(__entry->which, XFS_SWAPEXT_INODES),
+		  __print_symbolic(__entry->format, XFS_INODE_FORMAT_STR),
+		  __entry->nex,
+		  __entry->max_nex,
+		  __entry->broot_size,
+		  __entry->fork_off)
+)
+
+#define DEFINE_SWAPEXT_EVENT(name) \
+DEFINE_EVENT(xfs_swap_extent_class, name, \
+	TP_PROTO(struct xfs_inode *ip, int which), \
+	TP_ARGS(ip, which))
+
+DEFINE_SWAPEXT_EVENT(xfs_swap_extent_before);
+DEFINE_SWAPEXT_EVENT(xfs_swap_extent_after);
+
 #endif /* _TRACE_XFS_H */
 
 #undef TRACE_INCLUDE_PATH
diff --git a/fs/xfs/xfs_dfrag.c b/fs/xfs/xfs_dfrag.c
index 97711d8..eb4e404 100644
--- a/fs/xfs/xfs_dfrag.c
+++ b/fs/xfs/xfs_dfrag.c
@@ -254,6 +254,9 @@ xfs_swap_extents(
 		goto out_unlock;
 	}
 
+	trace_xfs_swap_extent_before(ip, 0);
+	trace_xfs_swap_extent_before(tip, 1);
+
 	/* check inode formats now that data is flushed */
 	error = xfs_swap_extents_check_format(ip, tip);
 	if (error) {
@@ -421,6 +424,8 @@ xfs_swap_extents(
 
 	error = xfs_trans_commit(tp, XFS_TRANS_SWAPEXT);
 
+	trace_xfs_swap_extent_after(ip, 0);
+	trace_xfs_swap_extent_after(tip, 1);
 out:
 	kmem_free(tempifp);
 	return error;
-- 
1.6.5