[Libguestfs] [nbdkit PATCH v2 0/2] caching .can_write

[Eric Blake]

This is a subset of the last half of the larger 9-patch series.  The
uncontroversial first half of that series is pushed, but here, I tried
to reduce the size of the patches by splitting out some of the more
complex changes, so that the rest of the changes remaining in the
series are more mechanical.  In turn, it forced me to write timing
tests, which let me spot another spot where we are wasting time, so
patch 2 is completely new.

As we discussed on IRC, we're early enough in the 1.16 release cycle
that I'll probably just push these when I'm happy with them, whether
or not a review turns up something (we can always do followup
patches).  But forcing me to reread the patches for legibility has
been a good exercise, because I really like how it forced me to spend
a good hour on the commit message of patch 1 explaining things, and
how patch 2 then fell out in 10 minutes of hacking to fix the problem
identified in passing in the patch 1 commit message.

Eric Blake (2):
  server: Cache per-connection can_write
  server: Remember .open(readonly) status

 server/internal.h           |  5 ++-
 server/backend.c            | 43 ++++++++++++++++++++-
 server/connections.c        |  5 ++-
 server/filters.c            |  6 +--
 server/plugins.c            |  4 +-
 server/protocol-handshake.c | 74 ++++++++++++++++++-------------------
 6 files changed, 88 insertions(+), 49 deletions(-)

-- 
2.21.0