Re: [Qemu-devel] [Qemu-block] [PATCH v5 6/6] docs/interop: add nbd.txt

[Vladimir Sementsov-Ogievskiy]

20.06.2018 23:58, John Snow wrote:
> On 06/20/2018 10:16 AM, Vladimir Sementsov-Ogievskiy wrote:
> > 20.06.2018 14:33, Eric Blake wrote:
> > > On 06/09/2018 10:17 AM, Vladimir Sementsov-Ogievskiy wrote:
> > > > Describe new metadata namespace: "qemu".
> > > >
> > > > Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> > > > ---
> > > >    docs/interop/nbd.txt | 37 +++++++++++++++++++++++++++++++++++++
> > > >    MAINTAINERS          |  1 +
> > > >    2 files changed, 38 insertions(+)
> > > >    create mode 100644 docs/interop/nbd.txt
> > > >
> > > > diff --git a/docs/interop/nbd.txt b/docs/interop/nbd.txt
> > > > new file mode 100644
> > > > index 0000000000..7366269fc0
> > > > --- /dev/null
> > > > +++ b/docs/interop/nbd.txt
> > > > @@ -0,0 +1,37 @@
> > > > +Qemu supports NBD protocol, and has internal NBD client (look at
> > > s/supports/supports the/
> > >
> > > > +block/nbd.c), internal NBD server (look at blockdev-nbd.c) as well as
> > > s/internal/an internal/2
> > >
> > > > +external NBD server tool - qemu-nbd.c. The common code is placed in
> > > s/external/an external/
> > >
> > > > +nbd/*.
> > > > +
> > > > +NBD protocol is specified here:
> > > s/NBD/The NBD/
> > >
> > > > +https://github.com/NetworkBlockDevice/nbd/blob/master/doc/proto.md
> > > > +
> > > > +This following paragraphs describe some specific properties of NBD
> > > > +protocol realization in Qemu.
> > > > +
> > > > +
> > > > += Metadata namespaces =
> > > > +
> > > > +Qemu supports "base:allocation" metadata context as defined in the NBD
> > > s/supports/supports the/
> > >
> > > > +protocol specification and defines own metadata namespace: "qemu".
> > > s/own/an additional/
> > >
> > > > +
> > > > +
> > > > +== "qemu" namespace ==
> > > > +
> > > > +For now, the only type of metadata context in the namespace is dirty
> > > > +bitmap. All available metadata contexts have the following form:
> > > maybe:
> > >
> > > The "qemu" namespace currently contains only one type of context,
> > > related to exposing the contents of a dirty bitmap alongside the
> > > associated disk contents.  The available metadata context has the
> > > following form:
> > Ok
> >
> > > > +
> > > > +   qemu:dirty-bitmap:<dirty-bitmap-export-name>
> > > > +
> > > > +Each dirty-bitmap metadata context defines the only one flag for
> > > > +extents in reply for NBD_CMD_BLOCK_STATUS:
> > > > +
> > > > +    bit 0: NBD_STATE_DIRTY, means that the extent is "dirty"
> > > > +
> > > > +For NBD_OPT_LIST_META_CONTEXT the following queries are supported
> > > > +additionally to "qemu:dirty-bitmap:<dirty-bitmap-export-name>":
> > > s/additionally/in addition/
> > >
> > > > +
> > > > +* "qemu:" : returns list of all available metadata contexts in the
> > > > +            namespace.
> > > > +* "qemu:dirty-bitmap:" : returns list of all available dirty-bitmap
> > > > +                         metadata contexts.
> > > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > > index e187b1f18f..887b479440 100644
> > > > --- a/MAINTAINERS
> > > > +++ b/MAINTAINERS
> > > > @@ -1923,6 +1923,7 @@ F: nbd/
> > > >    F: include/block/nbd*
> > > >    F: qemu-nbd.*
> > > >    F: blockdev-nbd.c
> > > > +F: docs/interop/nbd.txt
> > > >    T: git git://repo.or.cz/qemu/ericb.git nbd
> > > >      NFS
> > > Reviewed-by: Eric Blake <address@hidden>
> > >
> > > At this point, I think I'll touch up the issues I've spotted and
> > > submit a pull request, in order to make it easier for me to test my
> > > libvirt code.
> > Ok, thank you!
> ACK; the x- prefixes will help us get everything rolling together much
> faster and gives us some leeway to change things later as needed.
>
> Vladimir, can you jog our memories and let us know which series still
> need to hit QEMU for 3.0 for safe persistence/migration et al?
>
> (Not including any of my own qemu-img patches which I'll get to by freeze.)

not a trivial question :)

at least, there are the following pending patches:

migration
   [PATCH] migration: invalidate cache before source start

persistance
   [PATCH v2] qcow2: add overlap check for bitmap directory
   [PATCH] block/qcow2: fix logic around dirty_bitmaps_loaded
   thread "bug in reopen arch", there is no final solution for now
   also, I need to finally rethink and make a patch to don't have any 
persistent bitmaps in inactive mode

fleecing
   [PATCH] block/fleecing-filter: new filter driver for fleecing (new 
patch, but I remember, I've already started to discuss this..)

--
Best regards,
Vladimir