On Tue, Jun 02, 2026 at 12:10:08PM +0200, Christian Brauner wrote: > fs_holder_ops recovers the owning superblock from bdev->bd_holder, which > forces the holder to be exactly one superblock and prevents several > superblocks from sharing one block device. That's what erofs is doing. > > Introduce a global dev_t-keyed rhltable mapping each block device to the > superblock(s) using it. The holder argument becomes purely the block > layer's exclusivity token (a superblock, or a file_system_type for > shared devices) and is no longer needed by the fs specific callbacks.
Err, no. block devices need to have a specific owner. If erofs wants to share a device between superblock it needs to come up with an entity that owns the block devices which is not a superblock. IMHO sharing devices between superblocks is a bad idea, but that ship has sailed, but please keep it contained inside of erofs.
