1. 04 8月, 2017 14 次提交
  2. 01 8月, 2017 22 次提交
  3. 20 4月, 2017 1 次提交
  4. 19 4月, 2017 1 次提交
  5. 18 4月, 2017 2 次提交
    • P
      Merge remote-tracking branch 'remotes/famz/tags/block-pull-request' into staging · d1263f8f
      Peter Maydell 提交于
      # gpg: Signature made Tue 18 Apr 2017 15:58:32 BST
      # gpg:                using RSA key 0xCA35624C6A9171C6
      # gpg: Good signature from "Fam Zheng <famz@redhat.com>"
      # gpg: WARNING: This key is not certified with sufficiently trusted signatures!
      # gpg:          It is not certain that the signature belongs to the owner.
      # Primary key fingerprint: 5003 7CB7 9706 0F76 F021  AD56 CA35 624C 6A91 71C6
      
      * remotes/famz/tags/block-pull-request:
        block: Drain BH in bdrv_drained_begin
        block: Walk bs->children carefully in bdrv_drain_recurse
      Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
      d1263f8f
    • F
      block: Drain BH in bdrv_drained_begin · 91af091f
      Fam Zheng 提交于
      During block job completion, nothing is preventing
      block_job_defer_to_main_loop_bh from being called in a nested
      aio_poll(), which is a trouble, such as in this code path:
      
          qmp_block_commit
            commit_active_start
              bdrv_reopen
                bdrv_reopen_multiple
                  bdrv_reopen_prepare
                    bdrv_flush
                      aio_poll
                        aio_bh_poll
                          aio_bh_call
                            block_job_defer_to_main_loop_bh
                              stream_complete
                                bdrv_reopen
      
      block_job_defer_to_main_loop_bh is the last step of the stream job,
      which should have been "paused" by the bdrv_drained_begin/end in
      bdrv_reopen_multiple, but it is not done because it's in the form of a
      main loop BH.
      
      Similar to why block jobs should be paused between drained_begin and
      drained_end, BHs they schedule must be excluded as well.  To achieve
      this, this patch forces draining the BH in BDRV_POLL_WHILE.
      
      As a side effect this fixes a hang in block_job_detach_aio_context
      during system_reset when a block job is ready:
      
          #0  0x0000555555aa79f3 in bdrv_drain_recurse
          #1  0x0000555555aa825d in bdrv_drained_begin
          #2  0x0000555555aa8449 in bdrv_drain
          #3  0x0000555555a9c356 in blk_drain
          #4  0x0000555555aa3cfd in mirror_drain
          #5  0x0000555555a66e11 in block_job_detach_aio_context
          #6  0x0000555555a62f4d in bdrv_detach_aio_context
          #7  0x0000555555a63116 in bdrv_set_aio_context
          #8  0x0000555555a9d326 in blk_set_aio_context
          #9  0x00005555557e38da in virtio_blk_data_plane_stop
          #10 0x00005555559f9d5f in virtio_bus_stop_ioeventfd
          #11 0x00005555559fa49b in virtio_bus_stop_ioeventfd
          #12 0x00005555559f6a18 in virtio_pci_stop_ioeventfd
          #13 0x00005555559f6a18 in virtio_pci_reset
          #14 0x00005555559139a9 in qdev_reset_one
          #15 0x0000555555916738 in qbus_walk_children
          #16 0x0000555555913318 in qdev_walk_children
          #17 0x0000555555916738 in qbus_walk_children
          #18 0x00005555559168ca in qemu_devices_reset
          #19 0x000055555581fcbb in pc_machine_reset
          #20 0x00005555558a4d96 in qemu_system_reset
          #21 0x000055555577157a in main_loop_should_exit
          #22 0x000055555577157a in main_loop
          #23 0x000055555577157a in main
      
      The rationale is that the loop in block_job_detach_aio_context cannot
      make any progress in pausing/completing the job, because bs->in_flight
      is 0, so bdrv_drain doesn't process the block_job_defer_to_main_loop
      BH. With this patch, it does.
      Reported-by: NJeff Cody <jcody@redhat.com>
      Signed-off-by: NFam Zheng <famz@redhat.com>
      Message-Id: <20170418143044.12187-3-famz@redhat.com>
      Reviewed-by: NJeff Cody <jcody@redhat.com>
      Tested-by: NJeff Cody <jcody@redhat.com>
      Signed-off-by: NFam Zheng <famz@redhat.com>
      91af091f