On 7/21/24 6:01 PM, Dave Chinner wrote: > +The solution should already be obvious: we can exploit the sparseness of FSBNO > +addressing to allow AGs to grow to 1TB (maximum size) simply by configuring > +sb_agblklog appropriately at mkfs.xfs time. Hence if we have 16MB AGs (minimum > +size) and sb_agblklog = 30 (1TB max AG size), we can expand the AG size up > +to their maximum size before we start appending new AGs. there's a check in xfs_validate_sb_common() that tests whether sg_agblklog is really the next power of two from sb_agblklog: sbp->sb_agblklog != xfs_highbit32(sbp->sb_agblocks - 1) + 1 so I think the proposed idea would require a feature flag, right? That might make it a little trickier as a drop-in replacement for cloud providers because these new expandable filesystem images would only work on kernels that understand the (trivial) new feature, unless I'm missing something. -Eric
