On 04/24/2012 08:45 AM, Yang Zhang wrote: > I'm considering using ext4 on encrypted LVM (which uses LUKS and > dm-crypt). Will the transactional guarantees in ext4's journaling be > preserved? yes. dm-crypt operates in block layer, so it is filesystem responsibility to properly set needed bits for IO (flush cache, FUA - force unit access) and dmcrypt (device-mapper in general and block layer) must process them. (read http://lwn.net/Articles/400541/ for more info). In short, ext4, xfs, btrfs and similar filesystems supports all features over dmcrypt. (Except very old kernels, but most of stable distros backports patches.) > Bonus: where may I find authoritative information on this (besides the source)? The source is your best friend :-) basically this is the first commit introducing real barrier (later replaced with FUA) support http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=647c7db14ef9cacc4ccb3683e206b61f0de6dc2b You can also use blktrace to see how are fs requests propagated to physical media. Milan _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
