Hello, I've just realized that JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT breaks guarantees of data=ordered mode in ext4. The problem is that async commit code assumes that when a checksum of a transaction in the journal matches, all necessary data is on disk. This is true for metadata but need not be so for data - the whole transaction may be correctly on pernament storage while some data is still sitting in drive's caches. Thus if a power failure happens at that moment, we have broken guarantees of data=ordered mode. Seeing that async commit code isn't used by default anyway (I remember there used to be some problems with it), shouldn't we just rip it out? Honza -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
