On Tue, 11 Jan 2022, Hugh Dickins wrote: > But what is asynchronously reading /dev/loop0 (instantiating pages > initially, and reinstantiating them after blkdiscard)? I assume it's > some block device tracker, trying to read capacity and/or partition > table; whether from inside or outside the kernel, I expect you'll > guess much better than I can. > > Hugh That's udev. It reads filesystem signature on every block device, so that it can create symlinks in /dev/disk/by-uuid. If you open the block device for write and close it, udev will re-scan it. Mikulas
