On Wed, Feb 03, 2021 at 11:31:28AM -0500, Theodore Ts'o wrote: > On Wed, Feb 03, 2021 at 03:55:06AM -0700, Andreas Dilger wrote: > > > > It looks like this change will break the dirdata feature, which is similarly > > storing a data field beyond the end of the dirent. However, that feature also > > provides for flags stored in the high bits of the type field to indicate > > which of the fields are in use there. > > The first byte of each field stores > > the length, so it can be skipped even if the content is not understood. > > Daniel, for context, the dirdata field is an out-of-tree feature which > is used by Lustre, and so has fairly large deployed base. So if there > is a way that we can accomodate not breaking dirdata, that would be > good. > > Did the ext4 casefold+encryption implementation escape out to any > Android handsets? So from an OOB chat with Daniel, it appears that the ext4 casefold+encryption implementation did in fact escape out to Android handsets. So I think what we will need to do, ultiumately, is support one way of supporting the casefold IV in the case where "encryption && casefold", and another way when "encryption && casefold && dirdata". That's going to be a bit sucky, but I don't think it should be that complex. Daniel, Andreas, does that make sense to you? - Ted
