btrfs: tracepoints: add trace event for log_new_dir_dentries()

log_new_dir_dentries() is an important step called during a fsync, as
well as during rename and link operations on inodes that were previously
logged. Add trace events for when entering and exiting that function.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

2 files changed, 61 insertions, 2 deletions

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index f34dc9771dab..44c7d250b810 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -5902,9 +5902,13 @@ static int log_new_dir_dentries(struct btrfs_trans_handle *trans,
 	struct btrfs_inode *curr_inode = start_inode;
 	int ret = 0;
 
+	trace_btrfs_log_new_dir_dentries_enter(trans, start_inode);
+
 	path = btrfs_alloc_path();
-	if (!path)
-		return -ENOMEM;
+	if (!path) {
+		ret = -ENOMEM;
+		goto out;
+	}
 
 	/* Pairs with btrfs_add_delayed_iput below. */
 	ihold(&curr_inode->vfs_inode);
@@ -6023,6 +6027,8 @@ out:
 			kfree(dir_elem);
 	}
 
+	trace_btrfs_log_new_dir_dentries_exit(trans, start_inode, ret);
+
 	return ret;
 }
 
diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index d16de652a815..c13c1ce0b344 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -1175,6 +1175,59 @@ TRACE_EVENT(btrfs_log_all_new_ancestors_exit,
 			__entry->transid, __entry->ret)
 );
 
+TRACE_EVENT(btrfs_log_new_dir_dentries_enter,
+
+	TP_PROTO(const struct btrfs_trans_handle *trans,
+		 const struct btrfs_inode *inode),
+
+	TP_ARGS(trans, inode),
+
+	TP_STRUCT__entry_btrfs(
+		__field(	u64,     	root_objectid		)
+		__field(	u64,	 	ino			)
+		__field(	u64,		transid			)
+	),
+
+	TP_fast_assign(
+		TP_fast_assign_fsid(inode->root->fs_info);
+		__entry->root_objectid		= btrfs_root_id(inode->root);
+		__entry->ino			= btrfs_ino(inode);
+		__entry->transid		= trans->transid;
+	),
+
+	TP_printk_btrfs("root=%llu(%s) ino=%llu transid=%llu",
+			show_root_type(__entry->root_objectid), __entry->ino,
+			__entry->transid)
+);
+
+TRACE_EVENT(btrfs_log_new_dir_dentries_exit,
+
+	TP_PROTO(const struct btrfs_trans_handle *trans,
+		 const struct btrfs_inode *inode,
+		 int ret),
+
+	TP_ARGS(trans, inode, ret),
+
+	TP_STRUCT__entry_btrfs(
+		__field(	u64,     	root_objectid		)
+		__field(	u64,	 	ino			)
+		__field(	u64,		transid			)
+		__field(	int,	 	ret			)
+	),
+
+	TP_fast_assign(
+		TP_fast_assign_fsid(inode->root->fs_info);
+		__entry->root_objectid		= btrfs_root_id(inode->root);
+		__entry->ino			= btrfs_ino(inode);
+		__entry->transid		= trans->transid;
+		__entry->ret			= ret;
+	),
+
+	TP_printk_btrfs("root=%llu(%s) ino=%llu transid=%llu ret=%d",
+			show_root_type(__entry->root_objectid), __entry->ino,
+			__entry->transid, __entry->ret)
+);
+
 TRACE_EVENT(btrfs_sync_fs,
 
 	TP_PROTO(const struct btrfs_fs_info *fs_info, int wait),