[Libguestfs] [nbdkit PATCH v2 00/24] implement NBD_CMD_CACHE

[Eric Blake]

Since v1:
- rework .can_cache to be tri-state, with default of no advertisement
(ripple effect through other patches)
- add a lot more patches in order to round out filter support

And in the meantime, Rich pushed NBD_CMD_CACHE support into libnbd, so
in theory we now have a way to test cache commands through the entire
stack.

Eric Blake (24):
  server: Internal hooks for implementing NBD_CMD_CACHE
  plugins: Add .cache callback
  file, split: Implement .cache with posix_fadvise
  plugins: Implement .pread emulation cache
  plugins: Implement no-op .cache for in-memory plugins
  nbd: Implement NBD_CMD_CACHE passthrough
  sh: Implement .cache script callback
  ocaml: Implement .cache script callback
  plugins: Document lack of .cache in language bindings
  filters: Add .cache callback
  test-layers: Test .cache usage
  test-eflags: Test .can_cache support
  blocksize: Implement .cache rounding
  cache: Implement .cache
  cow: Implement .cache
  delay: Implement .cache
  error: Implement .cache
  log: Implement .cache
  offset, partition: Implement .cache
  readahead, xz: Implement .can_cache via emulation
  stats: Implement .cache
  truncate: Implement .cache
  filters: Pass through .can_cache for remaining filters
  nocache: Implement new filter

 docs/nbdkit-filter.pod                        |  42 +++++--
 docs/nbdkit-plugin.pod                        |  82 +++++++++++++
 docs/nbdkit-protocol.pod                      |   8 ++
 filters/cache/nbdkit-cache-filter.pod         |   6 +-
 filters/cow/nbdkit-cow-filter.pod             |  15 ++-
 filters/delay/nbdkit-delay-filter.pod         |   9 +-
 filters/error/nbdkit-error-filter.pod         |   8 +-
 filters/fua/nbdkit-fua-filter.pod             |   5 +-
 filters/log/nbdkit-log-filter.pod             |  10 +-
 filters/nocache/nbdkit-nocache-filter.pod     |  69 +++++++++++
 filters/noextents/nbdkit-noextents-filter.pod |   2 +
 filters/nozero/nbdkit-nozero-filter.pod       |   2 +
 plugins/lua/nbdkit-lua-plugin.pod             |   3 +-
 plugins/perl/nbdkit-perl-plugin.pod           |   2 +-
 plugins/python/nbdkit-python-plugin.pod       |   2 +-
 plugins/ruby/nbdkit-ruby-plugin.pod           |   2 +-
 plugins/sh/nbdkit-sh-plugin.pod               |  27 ++++-
 plugins/tcl/nbdkit-tcl-plugin.pod             |   3 +-
 configure.ac                                  |   5 +-
 common/protocol/protocol.h                    |   2 +
 filters/cache/blk.h                           |  10 +-
 filters/cow/blk.h                             |  16 ++-
 include/nbdkit-common.h                       |   4 +
 include/nbdkit-filter.h                       |   8 ++
 include/nbdkit-plugin.h                       |   2 +
 server/internal.h                             |   5 +
 filters/blocksize/blocksize.c                 |  29 +++++
 filters/cache/blk.c                           |  50 +++++++-
 filters/cache/cache.c                         |  53 ++++++++
 filters/cow/blk.c                             |  41 ++++++-
 filters/cow/cow.c                             |  90 ++++++++++++++
 filters/delay/delay.c                         |  27 ++++-
 filters/error/error.c                         |  32 ++++-
 filters/log/log.c                             |  29 ++++-
 filters/nocache/nocache.c                     | 113 ++++++++++++++++++
 filters/offset/offset.c                       |  12 +-
 filters/partition/partition.c                 |  12 ++
 filters/readahead/readahead.c                 |  13 ++
 filters/stats/stats.c                         |  23 ++++
 filters/truncate/truncate.c                   |  24 ++++
 filters/xz/xz.c                               |  15 ++-
 plugins/data/data.c                           |  11 ++
 plugins/ext2/ext2.c                           |  10 +-
 plugins/file/file.c                           |  37 ++++++
 plugins/floppy/floppy.c                       |  11 +-
 plugins/full/full.c                           |  13 +-
 plugins/iso/iso.c                             |  10 +-
 plugins/linuxdisk/linuxdisk.c                 |   9 ++
 plugins/memory/memory.c                       |  11 ++
 plugins/nbd/nbd.c                             |  24 ++++
 plugins/null/null.c                           |  13 +-
 plugins/ocaml/ocaml.c                         |  51 ++++++++
 plugins/partitioning/partitioning.c           |  11 +-
 plugins/pattern/pattern.c                     |  13 +-
 plugins/random/random.c                       |  13 +-
 plugins/sh/sh.c                               |  81 +++++++++++++
 plugins/split/split.c                         |  52 +++++++-
 plugins/zero/zero.c                           |  13 +-
 server/filters.c                              |  59 ++++++++-
 server/plugins.c                              |  44 +++++++
 server/protocol-handshake.c                   |   9 ++
 server/protocol.c                             |  26 ++++
 tests/test-layers-filter.c                    |  22 +++-
 tests/test-layers-plugin.c                    |  17 +++
 tests/test-layers.c                           |  36 ++++++
 filters/nocache/Makefile.am                   |  61 ++++++++++
 plugins/ocaml/NBDKit.ml                       |  16 ++-
 plugins/ocaml/NBDKit.mli                      |   5 +
 plugins/sh/example.sh                         |   7 ++
 tests/test-eflags.sh                          |  36 +++++-
 70 files changed, 1570 insertions(+), 63 deletions(-)
 create mode 100644 filters/nocache/nbdkit-nocache-filter.pod
 create mode 100644 filters/nocache/nocache.c
 create mode 100644 filters/nocache/Makefile.am

-- 
2.20.1