From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37038) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YuYXV-00054f-AD for qemu-devel@nongnu.org; Mon, 18 May 2015 23:49:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YuYXU-0004r9-AB for qemu-devel@nongnu.org; Mon, 18 May 2015 23:49:57 -0400 From: Fam Zheng Date: Tue, 19 May 2015 11:49:33 +0000 Message-Id: <1432036186-29903-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH v4 00/13] Fix transactional snapshot with dataplane and NBD export List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , qemu-block@nongnu.org, Juan Quintela , Jeff Cody , "Michael S. Tsirkin" , mreitz@redhat.com, Stefan Hajnoczi , Amit Shah , Paolo Bonzini v4: virtio-scsi-dataplane: Use assert in ctrl/event queue handler. [Paolo] Protect mirror complete in new patch 13. [Wen] Add Max's rev-by in 02, 03, 04. Fix 05, 06 per Max's comments. Reported by Paolo. Unlike the iohandler in main loop, iothreads currently process the event notifier used by virtio-blk ioeventfd in nested aio_poll. This is dangerous without proper protection, because guest requests could sneak to block layer where they mustn't. For example, a QMP transaction may involve multiple bdrv_drain_all() in handling the list of AioContext it works on. If an aio_poll in one of the bdrv_drain_all() happens to process a guest VQ kick, and dispatches the ioeventfd event to virtio-blk, a new guest write is then submitted, and voila, the transaction semantics is violated. This series avoids this problem by disabling virtio-blk handlers during bdrv_drain_all() and transactions. - Patches 1~3 add the block layer op blocker change notifier code. - Patches 4,5 secure virtio-blk dataplane. - Patch 6 protects virtio-scsi dataplane. - Patch 7 secures nbd export. - Patch 8~11 protect each transaction type from being voilated by new IO generated in nested aio_poll. - Patch 12 protects bdrv_drain and bdrv_drain_all. - Patch 13 protects mirror complete. Fam Zheng (13): block: Add op blocker type "device IO" block: Add op blocker notifier list block-backend: Add blk_op_blocker_add_notifier virtio-blk: Move complete_request to 'ops' structure virtio-blk: Don't handle output when there is "device IO" op blocker virtio-scsi-dataplane: Add "device IO" op blocker listener nbd-server: Clear "can_read" when "device io" blocker is set blockdev: Block device IO during internal snapshot transaction blockdev: Block device IO during external snapshot transaction blockdev: Block device IO during drive-backup transaction blockdev: Block device IO during blockdev-backup transaction block: Block "device IO" during bdrv_drain and bdrv_drain_all block/mirror: Block "device IO" during mirror exit block.c | 35 ++++++++++++++++++ block/block-backend.c | 6 +++ block/io.c | 22 ++++++++++- block/mirror.c | 8 +++- blockdev.c | 49 ++++++++++++++++++++---- blockjob.c | 1 + hw/block/dataplane/virtio-blk.c | 37 ++++++++++++++++--- hw/block/virtio-blk.c | 65 ++++++++++++++++++++++++++++++-- hw/scsi/virtio-scsi-dataplane.c | 82 +++++++++++++++++++++++++++++++---------- hw/scsi/virtio-scsi.c | 4 ++ include/block/block.h | 9 +++++ include/block/block_int.h | 3 ++ include/hw/virtio/virtio-blk.h | 17 +++++++-- include/hw/virtio/virtio-scsi.h | 3 ++ include/sysemu/block-backend.h | 2 + migration/block.c | 1 + nbd.c | 24 ++++++++++++ 17 files changed, 327 insertions(+), 41 deletions(-) -- 2.4.1