Jamie Lokier wrote:
Does O_DIRECT on btrfs still allocate new data blocks? That's not very direct :-) I'm thinking if O_DIRECT is set, considering what's likely to request it, it may be reasonable for it to mean "overwrite in place" too (except for files which are actually COW-shared with others of course).
O_DIRECT for databases is to bypass the OS file data cache. Those (oracle) who have long experience with it on unix know that the physical storage location can change on a filesystem. I do not think we want to make a special case, it should be up to the db admin to choose cow/nocow because if they want SNAPSHOTS they need cow. jim -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
