On Thu, Oct 05, 2006 at 03:42:24PM +1000, Neil Brown wrote: > As both dm and md create a block device using other block > devices as components, and as components can be added after creation, > it is theoretically possible to create a loop. Userspace LVM2 code takes steps to catch the most likely cases: exclusive open is required to create a PV; device-mapper dependencies are checked for loops when adding a PV to a VG. The general problem is harder as you also have to track through filesystems (losetup) etc. > This would probably give lockdep a major headache, but should detect > loops reliably, including loops involving both md and dm. I reckon the solution involves bd_claim* preventing loops in the device dependency tree. Alasdair -- agk@xxxxxxxxxx -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
