Re: [Libguestfs] [libnbd PATCH 0/3] opt_list_meta_context
On Tue, Sep 29, 2020 at 06:51:06AM -0500, Eric Blake wrote:
On 9/29/20 6:23 AM, Richard W.M. Jones wrote:
>This is not related to the current patch, but generally for libnbd:
>
>(1) Should we be testing interop separately for qemu-storage-daemon
>(qsd), or is qsd basically qemu-nbd in a new wrapper so it's not worth
>doing it?
Any thoughts on this one?
>(2) I found a bug in the new nbdinfo behaviour:
>
>$ nbdkit -fv file dir=/scratch
>
>(where /scratch is a directory with a lot of files in it)
>
>$ nbdinfo --version
>libnbd 1.5.3
>$ nbdinfo --list nbd://localhost
>[... lots of files shown ...]
>nbd_opt_info: recv: Connection reset by peer
>
>nbdkit gives this error:
>
>nbdkit: file[1]: error: client exceeded maximum number of options (32)
Yeah, we really ought to raise nbdkit's limits when .list_exports
returns a large list. We haven't yet released nbdkit 1.24 where the
file driver actually has a large .list_exports; but it may also be a
reason to figure out if libnbd should go to the effort of
re-connecting for the later portion of a list on servers like older
nbdkit that limit the length of the negotiation phase.
It raises the question about what the limit needs to be. If I point
nbdkit-file-plugin at a directory, the number of exports could be
pretty much unlimited. But at the smae time the options limit is
there for a fairly good reason. Should we change the client to
request info in groups of <N> (presumably requiring reconnection)?
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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