[Libguestfs] [libnbd PATCH 0/2] fix hangs against nbdkit 1.2

[Richard W.M. Jones]

On Mon, Mar 30, 2020 at 03:16:59PM -0500, Eric Blake wrote:
> On 3/30/20 2:59 PM, Eric Blake wrote:
> >nbdkit 1.2 as a server waits for read() to see EOF, even after the
> >client has sent NBD_CMD_DISC.  That was fixed in mbdkit 1.4; and most
> >modern NBD servers are smarter than this (they close() the write end
> >of their traffic soon after NBD_CMD_DISC).  But it's easy enough to
> >revert nbdkit commit c70616f8 to get back to a server with the same
> >behavior as the older nbdkit, at which point both 'cd /path/to/libnbd
> >&& make check PATH=/path/to/nbdkit'
> 
> Making the obvious correction:
> cd /path/to/libnbd && make check PATH=/path/to/nbdkit:$PATH
> 
> >and 'cd /path/to/nbdkit &&
> >/path/to/libnbd/run make check' will hang without this series.
> >
> >In short, this series is restoring the shutdown(SHUT_WR) call that got
> >lost from plugins/nbd/nbd.c when nbdkit switched to libnbd in commit
> >ab7760fc.

The series looks fine on inspection, although I guess it's the kind of
thing that may reveal weird deadlocks in some corner cases, but we'll
find those through testing.

ACK

Rich.

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