On May 09, 2007 10:02 -0700, Avantika Mathur wrote: > Metablock Groups: > > - Mingming mentioned that in the metablock group feature, the inode > metadata is not moved with the rest of the metadata. Ted will check > this, as he thought this had been implemented. > > - Online resize does not use metablock groups, and is currently limited > to 2TB. > > - Also need to remove sanity checks in the mount code > > - Once these issues are fixed, the metablock group feature can be turned > on by default for ext4 filesysytems In my recent investigation of META_BG, it appears that BOTH the kernel and e2fsprogs do NOT handle group metadata (bitmaps, itable) outside the group. In the kernel ext[234]_check_descriptors() requires the bitmaps and itable to be inside the group even though META_BG is supported for a long time. In e2fsck/super.c check_super_block() also requires that the bitmaps and itable be inside the group even though e2fsck has claimed META_BG for a long time. That means it is virtually impossible to allow the group metadata to move under the META_BG feature. It might be possible to predicate this change under both 64BIT and META_BG, though this is somewhat non-standard. Alternately, we could allow the relocation of bitmaps and itables under BIG_BG, which is itself covers the relocation aspects and also allows the ability to change the group size. Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc. - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
