Am 09.08.2019 um 15:18 hat Vladimir Sementsov-Ogievskiy geschrieben: > Hi! > > Hmm, hacking around backup I have a question: > > What prevents guest write request after job_start but before setting > write notifier? > > code path: > > qmp_drive_backup or transaction with backup > > job_start > aio_co_enter(job_co_entry) /* may only schedule execution, isn't it ? > */ > > .... > > job_co_entry > job_pause_point() /* it definitely yields, isn't it bad? */ > job->driver->run() /* backup_run */ > > ---- > > backup_run() > bdrv_add_before_write_notifier() > > ... > > And what guarantees we give to the user? Is it guaranteed that write notifier > is > set when qmp command returns? > > And I guess, if we start several backups in a transaction it should be > guaranteed > that the set of backups is consistent and correspond to one point in time...
Do the patches to switch backup to a filter node solve this automatically because that node would be inserted in backup_job_create()? Kevin
