On 26/02/2024 at 01:14, Matthew Wilcox wrote:
- create a logical volume in the free VG space
- blkdiscard the logical volume
Last time I checked, dm-crypt did not pass DISCARD requests through to
the underlying device because it's a security hazard.
AFAICS dm-crypt and cryptsetup have supported discard since Linux 3.1.
crypttab(5) states that "starting with Debian 10 (Buster), this option
is added per default to new dm-crypt devices by the Debian Installer".
Discard can still be disabled at the filesystem or swap level, or you
can disable dm-crypt discard after running blkdiscard.
