Hi As you maintain libblkid, I'd like to ask - would it be possible to add detection of filesystem block size to it? libblkid already has description of various filesystem superblocks, so it shouldn't be too hard. LVM needs to know the block size because when it enables caching for a logical volume using the dm-writecache target or integrity protection using the dm-integrity target, the block size of the device mapper target should match the block size of the underlying filesystem (if the cache has smaller block size than the filesystem, it is inefficient, if the cache has larger block size than the filesystem, the filesystem won't mount). Caching or integrity protection can be enabled on the fly for existing logical volumes (mounted or not mounted). XFS creates filesystems with 512-byte block size even on some modern SSDs, so the problem with small block size exists even today. Mikulas
