> --- a/design/XFS_Filesystem_Structure/allocation_groups.asciidoc > +++ b/design/XFS_Filesystem_Structure/allocation_groups.asciidoc > @@ -106,6 +106,10 @@ struct xfs_sb > xfs_lsn_t sb_lsn; > uuid_t sb_meta_uuid; > xfs_ino_t sb_metadirino; > + xfs_rgnumber_t sb_rgcount; > + xfs_rgblock_t sb_rgextents; > + uint8_t sb_rgblklog; > + uint8_t sb_pad[7]; And following on with my ranting about existing bits theme from the previous review: why are we documenting the in-memory xfs_sb here and not the on-disk xfs_dsb? > +| +XFS_SB_FEAT_RO_COMPAT_RTSB+ | > +Realtime superblock. The first rt extent in rt group zero contains a superblock > +header that can be used to identify the realtime device. See the section about > +the xref:Realtime_Group_Superblocks[realtime group superblocks] for more > +information. This is actually gone now. > +*sb_rgcount*:: > +Count of realtime groups in the filesystem, if the > ++XFS_SB_FEAT_INCOMPAT_RTGROUPS+ feature is enabled. ... will be zero if XFS_SB_FEAT_INCOMPAT_RTGROUPS is set, but no realtime subvolume exists ?
