On 10/13/2015 12:25 AM, Stefan Hajnoczi wrote: > On Fri, Sep 25, 2015 at 02:17:36PM +0800, Wen Congyang wrote: >> +static void backup_job_completed(void *opaque, int ret) >> +{ >> + BDRVReplicationState *s = opaque; >> + >> + if (s->replication_state != BLOCK_REPLICATION_DONE) { >> + /* The backup job is cancelled unexpectedly */ >> + s->error = -EIO; >> + } >> + >> + bdrv_op_block(s->hidden_disk, BLOCK_OP_TYPE_BACKUP_TARGET, >> + s->active_disk->backing_blocker); >> + bdrv_op_block(s->secondary_disk, BLOCK_OP_TYPE_BACKUP_SOURCE, >> + s->hidden_disk->backing_blocker); >> + >> + bdrv_put_ref_bh_schedule(s->secondary_disk); > > Why is bdrv_put_ref_bh_schedule() necessary?
It is copied from block_job_cb(). According to the comments in bdrv_put_ref_bh_schedule(): /* * Release a BDS reference in a BH * * It is not safe to use bdrv_unref() from a callback function when the callers * still need the BlockDriverState. In such cases we schedule a BH to release * the reference. */ If the comment is right, I think it is necessary to call bdrv_put_ref_bh_schedule() here. Because the job is created on the BDS s->secondary disk, backup_job_completed() is called in block_job_completed(), and we will still use s->secondary_disk in block_job_release(). Thanks Wen Congyang > . >