so that they are committed to storage before their associated metadata. This can be tricky to implement because it requires coordination within the operating system kernel between the file system driver and write cache. An out-of-order write hazard can also occur if a device cannot write blocks immediately to its underlying storage, that is, it cannot flush its write-cache to disk due to deferred write being enabled.

To complicate matters, many mass storage devices have their own write caches, in which they may aggressively reorder