f2fs: add tracepoint for f2fs_file_write_iter()

This patch adds tracepoint for f2fs_file_write_iter().
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/file.c

@@ -3035,15 +3035,21 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct inode *inode = file_inode(file);
 	ssize_t ret;
 
-	if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
-		return -EIO;
+	if (unlikely(f2fs_cp_error(F2FS_I_SB(inode)))) {
+		ret = -EIO;
+		goto out;
+	}
 
-	if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
-		return -EINVAL;
+	if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT)) {
+		ret = -EINVAL;
+		goto out;
+	}
 
 	if (!inode_trylock(inode)) {
-		if (iocb->ki_flags & IOCB_NOWAIT)
-			return -EAGAIN;
+		if (iocb->ki_flags & IOCB_NOWAIT) {
+			ret = -EAGAIN;
+			goto out;
+		}
 		inode_lock(inode);
 	}
 
@@ -3066,7 +3072,8 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 						clear_inode_flag(inode,
 								FI_NO_PREALLOC);
 						inode_unlock(inode);
-						return -EAGAIN;
+						ret = -EAGAIN;
+						goto out;
 				}
 
 		} else {
@@ -3077,7 +3084,8 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 			if (err) {
 				clear_inode_flag(inode, FI_NO_PREALLOC);
 				inode_unlock(inode);
-				return err;
+				ret = err;
+				goto out;
 			}
 		}
 		ret = __generic_file_write_iter(iocb, from);
@@ -3091,7 +3099,9 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 			f2fs_update_iostat(F2FS_I_SB(inode), APP_WRITE_IO, ret);
 	}
 	inode_unlock(inode);
-
+out:
+	trace_f2fs_file_write_iter(inode, iocb->ki_pos,
+					iov_iter_count(from), ret);
 	if (ret > 0)
 		ret = generic_write_sync(iocb, ret);
 	return ret;

include/trace/events/f2fs.h

@@ -533,6 +533,37 @@ TRACE_EVENT(f2fs_truncate_partial_nodes,
 		__entry->err)
 );
 
+TRACE_EVENT(f2fs_file_write_iter,
+
+	TP_PROTO(struct inode *inode, unsigned long offset,
+		unsigned long length, int ret),
+
+	TP_ARGS(inode, offset, length, ret),
+
+	TP_STRUCT__entry(
+		__field(dev_t,	dev)
+		__field(ino_t,	ino)
+		__field(unsigned long, offset)
+		__field(unsigned long, length)
+		__field(int,	ret)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= inode->i_sb->s_dev;
+		__entry->ino	= inode->i_ino;
+		__entry->offset	= offset;
+		__entry->length	= length;
+		__entry->ret	= ret;
+	),
+
+	TP_printk("dev = (%d,%d), ino = %lu, "
+		"offset = %lu, length = %lu, written(err) = %d",
+		show_dev_ino(__entry),
+		__entry->offset,
+		__entry->length,
+		__entry->ret)
+);
+
 TRACE_EVENT(f2fs_map_blocks,
 	TP_PROTO(struct inode *inode, struct f2fs_map_blocks *map, int ret),