Several improvements to the operation of the 'compatibility' property:
1) Improved handling of unrecognized features:
Change the way unrecognized features in compatibility files are handled.
* invalid features in files under /usr/share/zfs/compatibility.d
only get a warning (as these may refer to future features not yet in
the library),
* invalid features in files under /etc/zfs/compatibility.d
get an error (as these are presumed to refer to the current system).
2) Improved error reporting from zpool_load_compat.
Note: slight ABI change to zpool_load_compat for better error reporting.
3) compatibility=legacy inhibits all 'zpool upgrade' operations.
4) Detect when features are enabled outside current compatibility set
* zpool set compatibility=foo <-- print a warning
* zpool set feature@xxx=enabled <-- error
* zpool status <-- indicate this state
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Colm Buckley <colm@tuatha.org>
Closes#11861
1f3de97374