btrfs: tracepoints: add trace event for btrfs_log_all_parents()

btrfs_log_all_parents() 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, 73 insertions, 9 deletions

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 22066635f75f..90f5d1c830e4 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -7240,9 +7240,13 @@ static int btrfs_log_all_parents(struct btrfs_trans_handle *trans,
 	struct btrfs_root *root = inode->root;
 	const u64 ino = btrfs_ino(inode);
 
+	trace_btrfs_log_all_parents_enter(trans, inode);
+
 	path = btrfs_alloc_path();
-	if (!path)
-		return -ENOMEM;
+	if (!path) {
+		ret = -ENOMEM;
+		goto out;
+	}
 	path->skip_locking = true;
 	path->search_commit_root = true;
 
@@ -7251,7 +7255,7 @@ static int btrfs_log_all_parents(struct btrfs_trans_handle *trans,
 	key.offset = 0;
 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 	if (ret < 0)
-		return ret;
+		goto out;
 
 	while (true) {
 		struct extent_buffer *leaf = path->nodes[0];
@@ -7263,9 +7267,11 @@ static int btrfs_log_all_parents(struct btrfs_trans_handle *trans,
 		if (slot >= btrfs_header_nritems(leaf)) {
 			ret = btrfs_next_leaf(root, path);
 			if (ret < 0)
-				return ret;
-			if (ret > 0)
+				goto out;
+			if (ret > 0) {
+				ret = 0;
 				break;
+			}
 			continue;
 		}
 
@@ -7318,8 +7324,10 @@ static int btrfs_log_all_parents(struct btrfs_trans_handle *trans,
 			 * at both parents and the old parent B would still
 			 * exist.
 			 */
-			if (IS_ERR(dir_inode))
-				return PTR_ERR(dir_inode);
+			if (IS_ERR(dir_inode)) {
+				ret = PTR_ERR(dir_inode);
+				goto out;
+			}
 
 			if (!need_log_inode(trans, dir_inode)) {
 				btrfs_add_delayed_iput(dir_inode);
@@ -7332,11 +7340,14 @@ static int btrfs_log_all_parents(struct btrfs_trans_handle *trans,
 				ret = log_new_dir_dentries(trans, dir_inode, ctx);
 			btrfs_add_delayed_iput(dir_inode);
 			if (ret)
-				return ret;
+				goto out;
 		}
 		path->slots[0]++;
 	}
-	return 0;
+out:
+	trace_btrfs_log_all_parents_exit(trans, inode, ret);
+
+	return ret;
 }
 
 static int log_new_ancestors(struct btrfs_trans_handle *trans,
diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index 9f195d0d5378..2c145240d809 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -1067,6 +1067,59 @@ TRACE_EVENT(btrfs_log_inode_exit,
 			__entry->last_log_commit, __entry->ret)
 );
 
+TRACE_EVENT(btrfs_log_all_parents_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_all_parents_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),