Hi Richard, On Mon, Aug 19, 2019 at 07:10:33PM +0200, Richard Weinberger wrote: > Hi! > > struct erofs_super_block has "checksum" and "features" fields, > but they are not used in the source. > What is the plan for these? Yes, both will be used laterly (features is used for compatible features, we already have some incompatible features in 5.3). > > Same for i_checksum in erofs_inode_v1 and erofs_inode_v2. checksum field apart from super_block has been reserved again for linux-next. checksum in the super_block still exists and will be used sooner. The reason I discussed with Chao is since EROFS is a read-only filesystem, we will develop block-based checksum and integrity check to EROFS in the future version. It's more effectively than adding such fields to all metadata (some metadata is too large, we cannot calculate a checksum for the whole metadata and compare at runtime, but we can do block-based metadata chksum since EROFS is a read-only fs). > > At least the "features" field in the super block is something I'd > expect to be used. > ...such that you can have new filesystem features in future. Of course, "features" is for compatible features, "requirements" is for incompatible features. Both will be used in the future. Thanks, Gao Xiang > > Thanks, > //richard
