On Thu, May 14, 2015 at 10:37:21AM +1000, Dave Chinner wrote: > On Tue, May 12, 2015 at 11:48:02PM -0700, Jaegeuk Kim wrote: > > On Wed, May 13, 2015 at 12:02:08PM +1000, Dave Chinner wrote: > > > On Fri, May 08, 2015 at 09:20:38PM -0700, Jaegeuk Kim wrote: > > > > This definitions will be used by inode and superblock for encyption. > > > > > > How much of this crypto stuff is common with or only slightly > > > modified from the ext4 code? Is the behaviour and features the > > > same? Is the user API and management tools the same? > > > > > > IMO, if there is any amount of overlap, then we should be > > > implementing this stuff as generic code, not propagating the same > > > code through multiple filesystems via copy-n-paste-n-modify. This > > > will simply end up with diverging code, different bugs and feature > > > sets, and none of the implementations will get the review and > > > maintenance they really require... > > > > > > And, FWIW, this is the reason why I originally asked for the ext4 > > > encryption code to be pulled up to the VFS: precisely so we didn't > > > end up with a rapid proliferation of individual in-filesystem > > > encryption implementations that are all slightly different... > > > > Totally agreed! > > > > AFAIK, Ted wants to push the codes as a crypto library into fs/ finally, so > > I believe most part of crypto codes are common. > > Can I suggest fs/crypto/ if there are going to be multiple files? No problem at all. I'll do. > > > But, in order to realize that quickly, Ted implemented the feature to finalize > > on-disk and in-memory design in EXT4 as a first step. > > Then, I've been catching up and validating its design by implementing it in > > F2FS, which also intends to figure out what crypto codes can be exactly common. > > Excellent. That will make it easier and less error prone for other > filesystems to implement it, too! > > > As Ted mentioned before, since next android version tries to use per-file > > encryption, F2FS also needs to support it as quick as possible likewise EXT4. > > Fair enough. > > > Meanwhile, surely I've been working on writing patches to push them into fs/; > > currenlty, I did for cryto.c and will do for crypto_key.c and crypto_fname.c. > > But, it needs to think about crypto_policy.c differently, since it may depend > > on how each filesystem stores the policy information respectively; we cannot > > push all the filesystems should use xattrs, right? > > All filesystems likely to implement per-file crypto support xattrs, > and this is exactly what xattrs are designed for. e.g. we already > require xattrs for generic security labels, ACLs, etc. Hence > per-file crypto information should also use a common, shared xattr > format. That way it only needs to be implemented once in the generic > code and there's very little (hopefully nothing!) each filesystem > has to customise to store the crypto information for each file. Ok, I see. Let me take a look at that too. Thank you for sharing your thoughts. :) > > Cheers, > > Dave. > -- > Dave Chinner > david@xxxxxxxxxxxxx -- 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
