• Stefan Hajnoczi's avatar
    block: let mirror blockjob run in BDS AioContext · 5a7e7a0b
    Stefan Hajnoczi authored
    The mirror block job must run in the BlockDriverState AioContext so that
    it works with dataplane.
    
    Acquire the AioContext in blockdev.c so starting the block job is safe.
    
    Note that to_replace is treated separately from other BlockDriverStates
    in that it does not need to be in the same AioContext.  Explicitly
    acquire/release to_replace's AioContext when accessing it.
    
    The completion code in block/mirror.c must perform BDS graph
    manipulation and bdrv_reopen() from the main loop.  Use
    block_job_defer_to_main_loop() to achieve that.
    
    The bdrv_drain_all() call is not allowed outside the main loop since it
    could lead to lock ordering problems.  Use bdrv_drain(bs) instead
    because we have acquired the AioContext so nothing else can sneak in
    I/O.
    Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
    Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
    Message-id: 1413889440-32577-10-git-send-email-stefanha@redhat.com
    5a7e7a0b
mirror.c 25.7 KB