blockdev: acquire AioContext in change-backing-file

Add dataplane support to the change-backing-file QMP commands.  By
acquiring the AioContext we avoid race conditions with the dataplane
thread which may also be accessing the BlockDriverState.

Note that this command operates on both bs and a node in its chain
(image_bs).  The bdrv_chain_contains(bs, image_bs) check guarantees that
bs and image_bs are in the same AioContext.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2014-11-19 14:19:45 +00:00 committed by Kevin Wolf
parent e3442099a2
commit 729962f6db
2 changed files with 14 additions and 6 deletions

View file

@ -197,6 +197,7 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf,
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_RESIZE, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_DRIVE_DEL, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_BACKUP_SOURCE, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_CHANGE, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_COMMIT, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_EJECT, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,