site_archiver@lists.apple.com Delivered-To: darwin-dev@lists.apple.com But all the filesystem operations _do_ have transactional semantics. fs_begin_transaction(xxx); { ... do stuff ... } fs_{commit,rollback}_transaction(); -tim _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.appl... On Nov 30, 2005, at 1:53 PM, Peter Bierman wrote: The issue here is that someone is trying to read from the disk _behind the back_ of the filesystem. There is NO provision for that while the filesystem is in use. They have transactional semantics in that each individual operation is atomic, but they don't in that you can't group fs operations into a transaction. Imagine some new syscalls: In this particular case, you'd like 'xxx' to specify "don't show me writes made by other processes", but a mode where you can prevent your changes from becoming visible until you commit would be very useful too (say, if you want to create two files and have them show up atomically). Obviously there are a whole ton of design issues with doing this, problems this couldn't solve, and filesystems where this couldn't be implemented easily (if at all). This email sent to site_archiver@lists.apple.com