block/export: Move strong user reference to block_exports
commit3859ad36f0bdf45a6610d93296b52c9604b6d6f7
authorKevin Wolf <kwolf@redhat.com>
Thu, 24 Sep 2020 15:27:05 +0000 (24 17:27 +0200)
committerKevin Wolf <kwolf@redhat.com>
Fri, 2 Oct 2020 13:46:40 +0000 (2 15:46 +0200)
tree6f3079b4739c53840a3fe391ead09ef03847115a
parentd53be9ce55a38e430b88985f637f696bf99cbf0b
block/export: Move strong user reference to block_exports

The reference owned by the user/monitor that is created when adding the
export and dropped when removing it was tied to the 'exports' list in
nbd/server.c. Every block export will have a user reference, so move it
to the block export level and tie it to the 'block_exports' list in
block/export/export.c instead. This is necessary for introducing a QMP
command for removing exports.

Note that exports are present in block_exports even after the user has
requested shutdown. This is different from NBD's exports where exports
are immediately removed on a shutdown request, even if they are still in
the process of shutting down. In order to avoid that the user still
interacts with an export that is shutting down (and possibly removes it
a second time), we need to remember if the user actually still owns it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-20-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block/export/export.c
blockdev-nbd.c
include/block/export.h
nbd/server.c