Re: [Qemu-devel] [RFC PATCH 00/11] Block layer thread-safety, part 2

[Stefan Hajnoczi <stefanha@gmail.com>]

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On Wed, May 31, 2017 at 11:43:19AM +0200, Paolo Bonzini wrote:
> This part takes care of drivers and devices, making sure that they can
> accept concurrent I/O from multiple AioContext.  Only RFC for now because it
> depends on Kevin's QED conversion to coroutines, which is still in flux.
> 
> The following drivers are thread-safe without using any QemuMutex/CoMutex:
> crypto, gluster, null, rbd, win32-aio.
> 
> The following drivers already use mutexes for everything except possibly
> snapshots, which do not (yet?) need protection: bochs, cloop, dmg, qcow,
> parallels, vhdx, vmdk, curl, iscsi, nfs.
> 
> The following drivers already use mutexes for _almost_ everything: vpc
> (missing get_block_status), vdi (missing bitmap access), vvfat (missing
> commit), nbd (s->in_flight not protected), qcow2 (must call CoQueue APIs
> under CoMutex).  They are fixed by patches 1-6.
> 
> The following drivers must be changed to use CoMutex to protect internal
> data: qed (patches 7-9), sheepdog (patch 10).
> 
> The following driver must be changed to support I/O from any AioContext:
> ssh.  It is fixed by patch 11.
> 
> Paolo
> 
> Paolo Bonzini (11):
>   qcow2: call CoQueue APIs under CoMutex
>   coroutine-lock: add qemu_co_rwlock_downgrade and qemu_co_rwlock_upgrade
>   vdi: make it thread-safe
>   vpc: make it thread-safe
>   vvfat: make it thread-safe
>   nbd: make it thread-safe
>   qed: move tail of qed_aio_write_main to qed_aio_write_{cow,alloc}
>   block: invoke .bdrv_drain callback in coroutine context and from AioContext
>   qed: protect table cache with CoMutex
>   sheepdog: add queue_lock
>   ssh: support I/O from any AioContext
> 
>  block/io.c                 |  42 +++++++---
>  block/nbd-client.c         |  30 +++----
>  block/qcow2.c              |   4 +-
>  block/qed-cluster.c        |   4 +-
>  block/qed-l2-cache.c       |   6 ++
>  block/qed-table.c          |  24 ++++--
>  block/qed.c                | 195 +++++++++++++++++++++++++++------------------
>  block/qed.h                |  11 ++-
>  block/sheepdog.c           |  21 ++++-
>  block/ssh.c                |  24 ++++--
>  block/vdi.c                |  48 +++++------
>  block/vpc.c                |  20 ++---
>  block/vvfat.c              |   8 +-
>  include/block/block_int.h  |   2 +-
>  include/qemu/coroutine.h   |  19 +++++
>  util/qemu-coroutine-lock.c |  35 ++++++++
>  16 files changed, 326 insertions(+), 167 deletions(-)
> 
> -- 
> 2.13.0
> 
> 

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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